USMCA 2013

ICUS Report 2013-03 (serial No.73 )the 12th International Symposium
on New Technologies
for Urban Safety of Mega Cities in Asia
October 9-11, 2013
atHilton Hanoi Opera Hotel, Hanoi, Vietnam
andNational University of Civil Engineering, Hanoi, Vietnam
Edited by
Eiko Yoshimoto
Organized byInternational Center for Urban Safety Engineering,
Institute of Industrial Science, The University of Tokyo, Japan
National University of Civil Engineering, Vietnam
andVietnam Federation of Civil Engineering Association, Vietnam
Sponsored by
The Foundation for the Promotion of Industrial Science, Japan,
National Foundation for Science and Technology Development, Vietnam,
JFE Steel Corporation,
Delta Corporation,
SE Corporation,
Vietnam - Japan Engineering Consultant,
Department of Building and Industrial Engineering, NUCE, Vietnam,
Consultancy Company Limited of University of Civil Engineering,
FECON Foundation Engineering and Underground Construction,
JSC,
Consultant and Inspection Joint Stock Company of Construction,
Technology and Equipment – CONINCO,

Coteccons Group,
Aimil International,
Vietnam Geotechnical Engineering JSC
andGETECCO Corporation
Cooperated by
Ministry of Construction, Vietnam,
Ministry of Education and Training, Vietnam,
Japan International Cooperation Agency
And
Japan Society of Civil Engineering

SYMPOSIUM ORGANISERSCHAIRMENLe Van Thanh, President of National University of Civil Engineering (NUCE), Vietnam
Kimiro Meguro, Director of ICUS, IIS, The University of Tokyo
Pham Sy Liem, Vice President of VFCEASTEERING COMMITTEE
Pham Duy Hoa, Vice president of National University of Civil Engineering, Vietnam
Pham Hung Cuong, Vice president of National University of Civil Engineering, Vietnam
Do Huu Thanh, National University of Civil Engineering, Vietnam
Le Trung Thanh, Ministry of Construction, Vietnam
Ha Minh, Coninco, Vietnam
Mehedi Ahmed Ansary, Bangladesh University of Engineering Technology, Bangladesh
Sudhir Misra, Indian Institute of Technology Kanpur, India
Takeo Uomoto, Chief Executive, Public Works Research Institute, Japan
Yoshiaki Nakano, Director, IIS, the University of Tokyo, Japan
Tsuneo Katayama, Real-time Earthquake Information Consortium, Japan
Wei Cheng Fan, CPSR, Tsinghua University, China
Worsak Kanok-Nukulchai, Asian Institute of Technology, Thailand
Yoshifumi Yasuoka, Research Organization of Information and System, Japan
Do Van Hua, VFCEATECHNICAL COMMITTEE
Phan Quang Minh, National University of Civil Engineering, Vietnam
Nguyen Huu Dao, National University of Civil Engineering, Vietnam
Nguyen Truong Tien, President of VSSGME, Vietnam
Nguyen Viet Anh, National University of Civil Engineering, Vietnam
Nguyen Hoang Giang, National University of Civil Engineering, Vietnam
Dinh Van Hiep, National University of Civil Engineering, Vietnam
Chayanon Hansapinyo, Chiang Mai University, Thailand
Haruo Sawada, ICUS, IIS, the University of Tokyo, Japan
Kiang Hwee Tan, National University of Singapore, Singapore
Kimiro Meguro, ICUS, IIS, the University of Tokyo, Japan
Mafizur Rahman, Bangladesh University of Engineering Technology, Bangladesh
Pennung Warnitchai, Asian Institute of Technology, Thailand
Somnuk Tangtermsirikul, Thammasat University, Thailand
Srikantha Herath, United Nations University, Japan
Taikan Oki, ICUS, IIS, the University of Tokyo, Japan
Jiro Kuwano, Saitama University, JapanORGANIZING COMMITTEE
Reiko Kuwano, ICUS, IIS, the University of Tokyo, Japan
Akiyuki Kawasaki, ICUS, IIS, the University of Tokyo, Japan
Kohei Nagai, ICUS, IIS, the University of Tokyo, Japan
Pham Dang Khoa, National University of Civil Engineering, Vietnam
Dinh Van Thuat, National University of Civil Engineering, Vietnam
Contacts:
Nguyen Hoang Giang, National University of Civil Engineering (NUCE), Vietnam
Eiko Yoshimoto, ICUS, IIS, the University of Tokyo, Japan

PREFACE
On behalf of the Organizing Institutes of the 12th International
Symposium on New Technologies for Urban Safety of Mega Cites in Asia
(USMCA2013), I expressed our sincere welcome to all symposium participants
and distinguished keynote speakers.
In the Asia and Pacific-Rim regions, rapid economic development andpopulation growth and concentration is fast accelerating the pace of urbanization.
Unfortunately, the rapid expansion of infrastructure for urbanization is notadequately balanced with appropriate measures for their maintenance andmanagement, and urban disasters have resulted. During the last few years, there
were several big disasters in Asia and the Pacific Rim regions, such as killer
cyclones Sidr in Bangladesh (2007), Nargis in Myanmar (2008), and Aila in
Bangladesh and India (2009), and Typhoon Ketsna in Philippines (2009),
flooding in Mongolia (2009) and Pakistan (2010), the devastating earthquakes in
Sichuan, China (2008), Sumatra (2009), Samoa (2009) and Tohoku, Japan (2011),
and heat waves in Russia and Japan (2010). The number of fatalities and missing
reported due to these disasters was well over 200,000. These unprecedented
events show us the importance of urban safety.
The International Center for Urban Safety Engineering (ICUS) wasestablished in 2001 at the Institute of Industrial Science (IIS), the University ofTokyo, with the objectives of carrying out researches on urban safety andimplementing them towards the realization of safer cities, especially in Asia andthe Pacific Rim regions, in the 21st century. For over a decade, ICUS has been
actively tackling advanced researches, as well as the enhancement of networking,dissemination and information collection in order to fully realize ICUS’s vision.
And as a part of ICUS activities, ICUS has been annually co-organizing USMCA
since 2002 with its partners in the Asian region. In 2013, ICUS jointly organized
the 12th USMCA in Hanoi, Vietnam, with National University of Civil Engineering(NUCE) and Vietnam Federation of Civil Engineering Association (VFCEA).
The objectives of the symposium was to bring together decision makers,
practitioners and researchers involved in the field of urban safety to share theirexpertise, knowledge and experience in tackling the critical issues for safer cities
in Asia and the Pacific Rim regions. It also provided an environment to create andreinforce collaborative networks among experts in the fields relevant to urban
safety. The symposium focused on disaster response and recovery; risk assessment,
prediction, and early-warning; decision-making technologies; planning anddevelopment of urban infrastructure systems; life-cycle management of
infrastructure systems; climate change mitigation and adaptation; andapplication of geospatial technologies.
During the two-day symposium, 130 papers in thirteen parallel sessions
were presented with five papers by keynote speakers. We also had research
exhibitions in 13 booths on the first day. Total participants were 328 from 16
countries such as Vietnam, Thailand, China, Sweden, Bangladesh, Japan, Korea,
Mongolia, India, Indonesia, Singapore, Myanmar, Nepal, Pakistan, Canada andUSA.

I would like to thank all the members of the Steering, Technical andOrganizing Committees as well as the Symposium Secretariat for their hard work,
time and effort in putting this symposium together. I would also like to thank all
our sponsors for their generous support and contribution. Thanks are also due toall those who have contributed towards making this symposium successful.

Kimiro MEGURO
Director of ICUS, IIS, The University of Tokyo(Co-Chairman of Organizing Committee, USMCA2013)

Copyright and Reprint Permission:
Photocopy of an article is permitted for authors and other researchers for their own
reading and research. Abstracting and indexing of the papers are permitted but
acknowledgement should be given to “The 12th International Symposium on New
Technologies for Urban Safety of Mega Cities in Asia” and the authors of each specificpaper. Written permission should be obtained from the publishers prior to any other typeof reproduction.

Please contact:
International Center for Urban Safety Engineering (ICUS),
Institute of Industrial Science (IIS),The University of Tokyo, Japan
Tel: +81-3-5452-6472
Fax: +81-3-5452-6476

2013 Program Overview
Time

Tuesday, 8 October

09:00-16:00

Technical visits & sightseeing pre-conference day
Van Mieu - Imperial Academy – Nhat Tan Bridge

18:00-19:00

Registration at Hilton Hanoi Hotel

19:30-

Welcome dinnerTime

Wednesday, 9 October

08:00-08:30

Registration (Hilton Hanoi Hotel)
Opening address (Ballroom)

08:30-08:55(5*4)

WELCOME Speech (Dr. Le Van Thanh - President of National University of Civil Engineering)
WELCOME Speech (Prof. Kimiro Meguro - Director of ICUS, The University of Tokyo)
Opening Remark (Mr. Hideo Suzuki, Deputy Chief of Mission of Japan Embassy in Vietnam)
Opening Remark (Dr. Nguyen Thanh Nghi - Deputy Minister of Construction)
Opening Remark (Mr Fumihiko Okiura - Senior Representative of JICA Vietnam)
Moderator: Dr. Nguyen Hoang Giang

Keynote Speech (Ball room)

08:55-09:25

Advanced technologies for safety of underground expressway network in Tokyo
metropolitan area
Dr. Hiroshi Dobashi - President, Shutoko Engineering Co., Ltd, Japan
Moderator: Dr. Nguyen Hoang Giang

09:25-10:15

Group photo – Coffee break & Exhibitions
Keynote Speech (Ball room)

10:15-10:45
11:45-11:15
11:15-11:30

The structural design trend of supertall buildings in Vietnam
Prof. Phan Quang Minh - Dean of Building & Industrial Engineering Department – NUCE
Construction technologies for royal city complex
Mr. Tran Nhat Thanh – President of Delta Corporation
Advanced steel technologies for infrastructure
Dr. Hisaya Kamura- JFE Steel Corporation
Moderator: Dr. Nguyen Hoang Giang

11:30-11:40

Sponsor awards

11:40-13:00

Lunch at Hilton Hanoi Hotel 2nd floor

13:00-15:00

Lecture hall 1
Session 1-A：

Lecture hall 2
Session 2-B：

Session Chairs:
Dr. Takaaki KaatoDr.Dinh Van Thuat

Session Chairs:
Prof. Reiko Kuwano
Dr. Nguyen Hoang Giang

Tea-break at Exhibition zone

15:00-15:30
15:30-17:30

18:30-22:00

Session 3-C：

Session 4-D：

Session Chairs:
Prof. Taketo Uomoto
Dr. Nguyen Hung Phong

Session Chairs:
Prof. Haruo Sawada
Prof. Pham Quang Hung

Symposium dinner
Maison Sen Restaurant (bus will be leaving at 18:00)

Time

09:00-10:30

Thursday, 10 October
NUCE
Library building 2nd floor
Session 5-E1：

NUCE
Environmental Inst: 2nd floor
Session 6-F1

NUCE
G3 building 1st floor
Session 7-G1：

Session Chairs:
Prof. Nguyen Viet Anh
Prof. Sudhir Misra

Session Chairs:
Prof. Jiro Kuwano
Dr. Le Quang Hanh

Session Chairs:
Prof. Mehedi Ahmed Ansary
Prof. Do Huu Thanh

NUCE
Library building 2nd floor

Session 5-E2:

NUCE
Environmental Inst: 2nd
floor
Session 6-F2：

Session 7-G2：

Session Chairs:
Dr. Miho Ohara
Dr. Dinh Van Hiep

Session Chairs:
Prof. Tan Kiang Hwee
Dr. Tran. T. Viet Nga

Session Chairs:
Prof. Mikio Koshihara
Dr. Dao Danh Tung

10:30-10:45

10:45-11:25

11:30-12:00
12:00-13:30
13:30-15:50

Tea-break at session area

NUCE
G3 building 1st floor

Campus tour
Lunch at Long Vi restaurant
Session 5-E3

Session 8：

Session 9：

Session Chairs
Dr. Takaaki Kato
Prof. Pham Thuy Loan

Session Chairs:
Dr. Akiyuki Kawasaki
Dr. Win Win ZIn

Session Chairs:
Dr. Kohei Nagai
Dr.Pham Hoang Kien

15:50-16:00

Coffee break at G3 Hall, 2nd floor
G3 HallKeynote Speech (G3 Hall)

16:00-16:30
16:30-17:00
17:00-17:30

Utilization of unused and/or non-familiar materials for construction
Prof. Taketo Uomoto - Chief Executive, Public Works Research Institute / Professor
Emeritus, University of Tokyo
Water management in Vietnamese cities: present status and vision to future
Prof. Nguyen Viet Anh - National University of Civil Engineering
SanrikuTsunami and reconstruction of cities
Prof. Hiroshi Naito - Architect / Emeritus Professor, the University of Tokyo
Moderator: Dr. Nguyen Hoang Giang

Closing ceremony (G3 Hall)
Young award ceremony
Announcement of USMCA2014
NUCE’s closing speech
ICUS’s closing speech
Closing Banquet & Music

17:30-18:30

Moderator: Dr. Nguyen Hoang Giang

Time
08:00-20:00

Excursion Ha Long Bay

Friday, 11 October

Contents
Keynote Session

page

Advanced safety technology for underground expressway
in Tokyo metropolitan area

1

The structural design trend of supertall buildings in Vietnam

11

Utilization of unused and/or non-familiar materials for construction

23

Water management in Vietnamese cities: Present status and vision to future

31

Sanriku Tsunami and reconstruction of cities

43

Hiroshi DOBASHI
Phan Quang Minh
Taketo Uomoto

Nguyen Viet Anh
Hiroshi Naito

Oral Sessions
TECHNICAL PROGRAMME – DAY 1
Session 1-A:
A study on the development of risk assessment method for urban fire according tofire spread phenomena of exterior and wood materials

53

Self-help approach in housing reconstruction and beneficiaries’ satisfaction in
Palestine

63

Roles of self-help and mutual and local government aid in community-based disastermitigation
Midori YAMAGUCHI75

Sustainable safety and security in private rental properties for students in Hanoi:
the tenants’ perspective

83

Tsunami evacuation facilities in the damaged areas due to the Great East Japan
Earthquake: before and after

93

A new parking concept for a living quarter in Hanoi

101

Land use of super levees along the Arakawa River in the low-lying areas of Tokyo113

Anomaly detection of seasonal and annual environment changes of the world

121

Analysis on urban fire hazard and risk zones assessment mapping in Bangkok,
Thailand127

Ground anchors for revetment

137

Young Jin KWON

Adnan ENSHASSINGUYEN Thi Mai
Osamu MURAO

Quang Minh NGUYEN
Hitoshi NAKAMURAI
Haruo SAWADA

Praopanitnan CHAIYASANG
Haruka SAITO

Session 2-B:
Structure maintenance methods and disaster measures of Tokyo Metro

143

For the safety and the sustainable development of Ho Chi Minh City

153

History and recent trend of Tokyo Metro’s tunnel construction technology

165

High-raised urban expressway to mitigate congested heavy traffic

177

Application of water screen fire prevention systems

185

Evaluation of applicability of steel pipe piles in Vietnam

195

Contemporary timber building in Japan, 2013

207

A useful approach to identify and analyze factors affecting safety on construction
site with lifting equipment in Vietnamese environment

209

Hiroyuki SHINSAI

Ngoc Tran NGUYEN
Shinji KONISHI
Yukitake SHIOI
Reiko AMANO

Shunsuke USAMI

Mikio KOSHIHARA
Thanh Long NGO

Session 3-C:
Recycled glass concrete beams under bending and shear

219

Strength of beam-column joint in soft-first story RC buildings

229

Parametric study for displacement based analysis of unreinforced brick masonrywalls subjected to lateral loads

241

A study of the influence of the bending radius of reinforcement bar on the failure
mechanism of L-shaped beam column joint by 3D discrete model251

An experimental investigation of a self-oscillating multi-heat pipe using pure waterand alumina nanofluid, respectively

263

Earthquake behavior of reinforced concrete framed buildings on hill slopes

275

Using surface roughness as a performance parameter for RC wastewater pipes

289

Capacity factors for implementing urban infrastructure projects in India

301

Using GFRP for repair and rehabilitation of RC frames

313

Kiang Hwee TAN

Toshikatsu ICHINOSE
Archanaa DONGRE
Kohei NAGAI

Dao Danh Tung

Ajay K SREERAMA
Rahul YADAV
Yehyun AN

Kunwar K BAJPAI

Session 4-D:
Savar building tragedy in Bangladesh: Way forward

325

Secular changes in people’s consciousness regarding earthquake early warning-Based on national survey (2009-2012) in Japan-

335

Mehedi Ahmed ANSARY
Miho OHARA

Prediction on sediment related disaster through the satellite rainfall data

345

Effect of foreign government advisories on foreigners’ post-disaster action after the2011 Great East Japan Earthquake

353

Further modification and working stress design using K-stiffness method on softand hard foundations

363

Survey of sub-surface cavities in the liquefied ground caused by the Great East
Japan Earthquake

381

Model tests simulating sub-surface cavities formed in the liquefied ground393

Climate change effects in Chindwin River basin, Myanmar

401

Seismic stability of reinforced soil walls in the 2011 Tohoku Earthquake

413

Ideal regional disaster management plan based on the experience from the 2011
Great East Japan Earthquake

423

Yoshikazu SHIMIZU
Akiyuki KAWASAKI

Sowarapan DUANGKHAE
Ryoko SERA

Reiko KUWANO
Win Win ZIN

Jiro KUWANO

Kimiro MEGUROTECHNICAL PROGRAMME – DAY 2
Session 5-E1:
Information collection and vulnerability of foreign students during the 2011
Tohoku Earthquake and 2011 Thai flood

431

Risks from in-city construction works to urban inhabitants’ safety in Hanoi:
the city residents’ perspective

443

Increasing community awareness of earthquake risk through children education:
A case study of Dien Bien City in Vietnam

453

Public housing after hurricane: Urban renewal or removal?
The case study of Beaumont and Galveston,Texas, U.S.A.

467

Flood adaptive cities towards climate change adaption and urban development inMekong Delta

477

Analysis on influencing factors of community participation in disastercountermeasures regarding land subsidence and climate change case study:
North Jakarta (Indonesia)and Shinkoiwa Community,
Katsushika City, Tokyo (Japan)

491

Assessment of multi-hazard risk in mega cities in Japan

501

Development of an innovative stormwater management framework towardbuilding cities resilient to climate change in Vietnam

507

Assessment of potential greenhouse gas emission of domestic solid waste treatment
in Hanoi, Vietnam

519

Michael HENRYNGUYEN Duy Cuong
Pham Thi Hong
Tho TRAN

Thu Trang LE

Maria Bernadet Karina Dewi
Tomofumi IKENAGA
Duong Du Bui

Minh Giang HOANG

Session 5-E2:
Optimisation of indoor environmental quality and energy consumption within
urban office buildings529

A basic study on future strategy for effective disaster information dissemination:
Case study in Thailand

541

Analysis of initial disaster responses for disaster management stakeholders inemergency and recovery phase for sustainable disaster management system

551

Planning tool for urban sustainable development management in Vietnam cities

561

Tran Ngoc Quang

Niwat APICHARTBUTRA
Muneyoshi NUMADA

Nguyen Thi Thanh MAI

Session 5-E3:
The integration approach for broad-scale land-use change prediction modelling

569

China’s growing civil society for disaster response

581

Survey on current system for disseminating disaster early warning
by cell phones in Japan

591

Assessing recovery: existing practices and evaluation measures

599

Study on earthquake early warnings provided to public/advanced users at the2011 off the Pacific coast of Tohoku Earthquake

609

Study on victim transportation planning considering street blockades-Case study of expected Tokyo inland earthquake-

619

Solutions for a higher living quality for people in Hanoi’s Old Quarter629

A study on post-disaster housing by analyzing the pattern between the regional
characteristics and people’s preference

639

Proposed solutions to quality improvement and integrated operations of technicalinfrastructure systems for new urban areas in Vietnam645

Study on applicability of remote building damage assessment system for large-scale earthquake disasters - Focused on the photo upload system -657

Safe and sustainable energy use in tall residential buildings in Hanoi:
Practices and orientation

667

Development of simulation exercise for emergency response headquarters focusedon management by objectives

675

Comparing benefits of hydropower development in two boundary systems in the
Mekong

677

Anh Nguyet DANG
Xiaoge XU

Takanori SAWARA

Yasmin BHATTACHARYA
Ayaka NISHIGUCHIFei JIANG

LE Thi Hoai An

Tomoko MATSUSHITA
Ngoc Khoa HO
Makoto FUJIU

PHAM Thuy An

Shinya KONDO

Seemanta Sharma BHAGABATI

Optimization the use of rice husk ash to increase bearing capacity of difficult soil
foundation for low cost housing in Semarang’s Urban areas.

Silvia Fransisca Herina

679

Session 6-F1:
Scale effects on the shear strength of waste in coastal landfill sites

681

Triaxial tests for elastic wave measurement with associated matric suctionon unsaturated fine content sandy soil

691

Effect of permeability of dam body and foundation on free surface

703

Experimental application of biogrout to sand with fines711

The deformation of flexible pipe buried in soil with different degree of compaction

723

Triaxial test for the evaluation of internal erosion733

A study of bored pile bearing capacities at some locations in Hanoi, Vietnam

743

A technique of image processing analysis recommended for researchof laterally loaded pile using a system of X-ray CT scanner

757

Asessment of urbanization impact to temperature, rainfall and flooding
situation of Ha Noi city taken into account climate change

767

Nguyen Chau LAN

Laxmi Prasad SUWALThi Dieu Chinh LUU
Tsubasa Sasaki

Ngoc Duyen NGUYEN
Mari SATO

Thuy Diep DUONG
Khoa Dang PHAM
Vu Minh Cat

Session 6-F2:
Study on carbonation and pore structure of cementitous materials exposed
to supercritical CO2

777

Effect of the application of surface penetrants on the mass transport
properties of concrete

787

Influence of coexistent ions in seawater on the chloride permeability of concrete

795

Performance of crack self-healing concrete by development of semi-capsulation
technique for functional effective ingredients

803

Ryosuke HIRAI

Nozomu SOMEYA
Toshiya CHIBA
Vu Viet Hung

Session 7-G1:
Response characteristics of R/C buildings considering impulsive forceof tsunami drifting objects

813

NIOM analysis of vertical array records observed in RC structure buildings

823

Residual seismic capacity evaluation of RC frame with weak-beams
based on energy absorption capacity

833

Low temperature behavior and modeling of high damping rubber bearings

843

Ho CHOI

Yusuke ODA

Chunri QUAN

Tomoya MATSUMOTO

The structural performance of traditional frames with through columns
about townhouses in Japan

851

Modeling and earthquake response analysis of traditional timber
frames including Kumimono

859

Optimization of PP-band Mesh Connectivity for Cost and Time
Effectiveness in Seismic Retrofitting of Masonry Structures

869

Monitoring system for Nguyen Van Troi -Tran Thi Ly stay cable bridge
during construction and for service stage

881

Practical evaluation method of collapse limit displacement based on seismic
damage of structural members

889

Hiromi SATO
Iuko TSUWA

Adnan Mahmood DARNGUYEN Phuong Duy
Kazuto MATSUKAWA

Session 7-G2:
Ultra high performance concrete using a combination of silicafume
and limestone in Vietnam

899

Analytical and experimental study for seismic design of a typical bridge
pier according to Vietnamese earthquake design code909

Influence of climate change to loads and actions to buildings

919

Test methods for evaluation of sulfate resistance of limestone powder
replacing cement mortars

929

Nguyen Cong Thang
Pham Hoang KIENNGUYEN Vo Thong

Ittiporn SIRISAWAT

Session 8:
Hanoi towards 2030 - Substance flow analysis supporting the planning process

941

Comparisons nitrogen removal capacities by anammox process using different
biomass carriers

955

Investigation of residential water end-use in urban areas of Hanoi

965

Pollution and eutrophication control in urban lakes

977

Introducing speed humps as a countermeasure for enhancing traffic safetyin urban residential areas: Some insights from experiments in Japan

987

Some research on air quality of Ulaanbaatar City (Mongolia) in wintertime

999

Investigating future yield and adaptation measures in rice production
under climate change scenarios in Quang Nam province, Vietnam

1003

Anaerobic submerged membrance bioreactor (AnMBR) for decentralized
municipal wastewater treatment in Vietnam conditions

1017

Viet Anh NGUYEN

TRAN Thi Hien Hoa
Huyen T.T. DANG
Ha D. TRAN

Do Duy DINH
Enkh-Uyanga

Trang BUI THI THU
T. T. V Nga

HAN-Sense: A solution for traffic air pollution monitoring in hanoi cityusing wireless sensor networks

1025

Towards sustainable transportation through introductionof eco-drive management system for vehicle fuel efficiency

1037

Compressive strength of ordinary and bridge high performance steel plates:
Proposal of nominal design value and corresponding partial safety factor

1053

Hybrid technology of up-flow anaerobic filter and membrane bio-reactor
for recovery energy from rich organic waste stream1065

The risk assessment by the AHP method and characteristics of the landslides
in Sa Pa ,Lao Cai province northern Vietnam

1077

Quang Duc LE

Dinh Van HIEP

Viet Duc DANG

Thu Hang DUONG
Takami KANNO

Session 9:
Crack identification in frame structures by using the wavelet
analysis of mode shapes

1079

Mechanical behavior of high damping rubber bearings at low temperatures

1091

Examples of proposals for emergency countermeasure and research methodsof landslide in Vietnam

1099

Ultra rapid strength development in dry-mix shotcrete for emergency supportand harsh mining conditions

1109

A study of the behavior of a beam column joint with complex arrangementof reinforcing bars by finite element analysis

1119

Effects of crystalline admixture on compressive strength and shrinkage
of concrete with pozzolanic materials

1129

Effect of heating and re-curing on crack characteristics in cement paste

1141

Introduction of CAESAR’s research activity utilizing decommissioned
bridge in Japan

1149

Performance of different sacrificial anode materials on corrosion protectionof reinforcing steel

1159

Investigation on performance of concrete and mortar using active
compound powder1169

A simple method to determine the unsaturated soil shear strengthwith respect to a wide range of matric suction

1179

Large prefabricated pile foundation, a solution for high-rise buildings in Hanoi

1191

Sustainability in the concrete industry for construction of mega cities

1199

TranVan Lien

Dung Anh NGUYEN
Do Ngoc Trung

Jean-Daniel LEMAY
Liyanto EDDY

Viet TRAN HUU

Yuto HARAGUCHI
Akiko HIROE

Pakawat SANCHAROEN

Parnthep JULNIPITAWONG
Hoang Viet NGUYEN
Bao Viet NGUYEN
Kiên TONG

Slump control of fresh concrete by re-dosing polycarboxylic based
superplasticizer and comparison with naphthalene based

Ram Hari DHAKAL

1211

Photograph

ICUS Report 73

ICUS Report 73

Welcome boards

View of registration at Hilton Hotel

Inauguration ceremony

View of participants of opening address

New Technologies for Urban Safety of Mega Cities in Asiaii

October2013,2013,Hanoi,
Hanoi,Vietnam
Vietnam
October

View of participants of keynote speech session

Dr. Le Van Thanh,President, NUCE, Vietnam

Mr. Hirofumi Miyake,Embassy of Japan in Vietnam

ii iiProf. Kimiro Meguro,
Director, ICUS, Japan

Mr. Nguyen Dinh Toan,
Deputy Minister of Construction, Vietnam

Mr. Fumihiko Okiura,
Senior Representative, JICA Vietnam

Technologies
for Urban
Safetyof Mega
CitiesAsia
New New
Technologies
for Urban
Safetyof Mega
CitiesininAsia

ICUS Report 73

ICUS Report 73

Invited speakers (Keynote)

Dr. Hiroshi Dobashi,
President, Shutoko
Engineering Co., Ltd,Japan

Prof. Phan Quang Minh,
Dean, Building & Industrial
Engineering Dept.
NUCE, Vietnam

Dr. Taketo Uomoto,Chief Executive Public
Works Research Institute,Japan

Mr. Tran Nhat Thanh,
Chairman, DELTA Group,
VietnamProf. Nguyen Viet Anh,
NUCE, Vietnam

Dr. Hisaya Kamura,
General Manager,
JFE Steel Corporation,
VietnamProf. Hiroshi Naito, Architect,
Professor Emeritus,
The Univ. of Tokyo, Japan

Exhibition area

New Technologies for Urban Safety of Mega Cities in Asia

iii

iii

October 2013, Hanoi, Vietnam
October 2013, Hanoi, Vietnam

Exhibition area

Invited speakers

Prof. Kiang Hwee Tan,National University of Singapore,
SingaporeProf. Sudhir Misra,
IIT, Kanpur, India

Mr. Khin Maung Maung,
CEC menber,
Myanmar Engineering Society,
Myanmariv
iv

Prof. Mehedi Ahmed Ansary,
BUET, Dhaka, Bangladesh

Dr. Win Win Zin,
Yangon Technological University,
Myanmar

New Technologies for Urban Safety of Mega Cities in Asia
New Technologies for Urban Safety of Mega Cities in Asia

ICUS
ICUSReport
Report7373

Second day at National University of Civil Engineering

Closing ceremony

Prof. Pham Hung Cuong, Vice-Rector, NUCE, Vietnam
View of closing ceremony

Young-Researcher- Award recipientswith Prof. Kuwano (left) and Prof. Meguro (right)
Awardees: Mr. Chunri Quan, ,Mr. Tomofumi
Ikenaga,
Mr. Tsubasa Sasaki, Ms. Naoc Duyen Nguyen,
UTokyo, Japan and Mr. Nguyen Chou Lan, NUCE,
Vietnam(from the second left to the right)
Vietnam student-staff with organizers

New Technologies for Urban Safety of Mega Cities in Asia

vv

October 2013,
October
2013,Hanoi,
Hanoi,Vietnam
VietnamGroup photos

Press coverage by VTV and Hanoi TV

ICUS members meet with Dr. Le Van Thanh, President of NUCE

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Lunch, break, banquet and farewell party

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VietnamWhole day tour : Visit to Van mieu, Imperial Academy and Nhat Tan Bridge on 8th October

Tour

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Whole day tour: Visit to Ha Long bay on 11th October

Visit to Vietnam city

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New Technologies for Urban Safety of Mega Cities in Asia

Keynote Session

Advanced safety technology for underground
expressway in Tokyo metropolitan area
Hiroshi DOBASHI
President, Shutoko Engineering Co., Ltd., Japanh.dobashi118@shutoko.jp
ABSTRACTThe Metropolitan Expressway network serves as a major traffic facility that
supports socio-economic activities in the Tokyo metropolitan area and it currently
extends for approximately 300 km. With economic growth and rapid developmentof the city, effective utilization of urban space is highly required for developmentof infrastructures such as the Metropolitan Expressway and the subways. In
addition, with consideration of environmental conservation, undergroundstructures instead of viaduct structures have been recently employed. As a result,
the Central Circular Shinjuku and Shinagawa Routes of the Metropolitan
Expressway are mostly comprised of tunnel structures with 18km in total length,
which is the longest tunnel in urban areas. Therefore, management and operation
system of the urban long tunnel has been developed to secure safety and prevent
disasters such as fire or other accidents in addition to development of innovative
tunnel construction technology. Advanced safety technology would be expected tocontribute further to effective utilization and development of underground spacein urban areas.
Keywords: environmental conservation, safety and disaster prevention system,
innovative tunnel construction technology
1. INTRODUCTION
The Metropolitan Expressway network, on which construction began more than
50 years ago, currently extends for approximately 300 km (Fig.1). In 2011, it
carried about 1 million vehicles and about 2 million passengers per day. Although
the total length of the network in service is only 15% of the total length of major
city roads in the Tokyo metropolitan area, it carries approximately 30% of thetotal traffic in terms of vehicle-kilometrage, indicating the degree of utilization.
Since it carries approximately 28% of freight transportation in the area, it isconsidered to function approximately twice more in vehicle-kilometrage andapproximately three times more in freight transportation than other major city
roads. As described above, the Metropolitan Expressway network serves as amajor traffic facility that supports socio-economic activities in the Tokyo
metropolitan area, and it is a road system that is indispensable to the lifestyle ofthe people in the area.
The operation of an effective traffic system in the Tokyo metropolitan area
requires the creation of a network with a appropriate balance between radial and1

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 1: The network of Tokyo Metropolitan Expressway
circular routes. The Metropolitan Expressway Company Limited completed theCentral Circular Shinjuku Route in 2009, and is currently in the process ofbuilding the Central Circular Shinagawa Route that forms a southern part of theCentral Circular Route due to be completed in the fiscal year of 2014.
The Central Circular Shinjuku and Shinagawa Route employ a tunnel structure toaccommodate the land use patterns along the route and the concerns forenvironmental conservation, hence enabling the construction of expressways indensely populated urban areas. In order to secure the financial feasibility of the
project, appropriate measures are taken to reduce the costs and construction period
based upon the use of the new technology. Furthermore, an important aspect ofurban long tunnel construction is the need for safety measures especially against
fire. Therefore, traffic and facility operation such as provision of information,
ventilation system and so on, are required.
This paper provides the innovative tunnel construction technology, andmanagement and operation system of the urban long tunnel which has been newly
developed to secure safety and prevent disasters such as fire or other accidents.

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2. THE CENTRAL CIRCULA SHINJUKU AND SHINAGAWA ROUTE
2.1 The Shinjuku Route (Yamate Tunnel)
The Shinjuku Route is an 11 km expressway between Route No.3 and No.5 (asshown in Figure 1) that is designed with two lanes in each direction and has adesign speed of 60 km/h. To accommodate the land use patterns along the route,and in order to conserve a surrounding environment and make efficient use oflimited public urban space, the Shinjuku Route is designed as a tunnel structure
under the circular road Route No.6 (Yamate Dori), which will be widened to 40m
in the same period. Therefore, the alignment of the tunnel, the types ofunderground structures, and the construction methods must take account ofconstraint conditions such as the crossing of rivers, subways, trunk roads andrailways, as well as the accommodation of major existing public utilities. As
further characteristic feature of the Shinjuku route, i.e. the short average distance
between the access ramps, it has a short average distance between access ramps,
with six access ramps to the ground-level street and three junctions connecting theradial routes of other Metropolitan Expressway.
Because of the complicated structure of the ramps and the large number of them,transversal ventilation system is employed with nine ventilation stations installedon this route. Seven of these ventilation stations are installed underneath thecircular road No.6, while only the ventilation towers are built above ground. Thisis due to the limitations in the availability of space above ground. The remaining
two ventilation stations are installed above ground in spaces off the road.
2.2 The Shinagawa Route
The Shinagawa Route is an 9.4 km expressway between Route No.3 and Bayshore Route (as shown in Figure 1) that is designed with two lanes in eachdirection and has a design speed of 60 km/h. The Shinagawa Route is also
employs a tunnel structure under the circular road Route No.6 and beneath
Meguro river to accommodate the land use patterns along the route, and in order
to conserve a surrounding environment and make efficient use of limited public
urban space. The Shinagawa Route has one ramp accessing to the surface street
and two junctions with existing routes.
Since less number of the ramp along the route, the longitudinal ventilation system
is employed with four ventilation stations installed on this route. Two of these
ventilation stations are installed under the circular road No.6. This is due to thelimitations in the availability of space above ground. The remaining two
ventilation stations are installed above ground beside the road
3. INNOVATIVE TUNNEL CONSTRUVTION TECHNOLOGY
The tunnel construction method for the Shinjuku Route was originally planned
to be a cut-and-cover method. However, in the 1990’s, shield tunnels with 14m indiameter were completed and recent developments on shield tunnel have beendeveloped in construction methods for underground junctions and for entrancesand exits. As a result, shield tunneling method with a large diameter is employed

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Vietnamfor approximately 80% of the entire tunnel section instead of a cut-and-covermethod. In addition, upon adopting large diameter shield tunneling, the following
new design and construction technologies have been developed and/or introduced
to reduce construction costs.
3.1 Establishment of a rational design method for shield tunnel segments
In the design of the segment, the structure of joints on a segment is properly
evaluated by using the beam-spring model in the calculation method rather thanby the conventional two-dimensional ring calculation model. The beam-springmodel calculation evaluates reduction of bending rigidity and splice effects ofstaggered arrangement by using a model in which a segment is considered as a
curved beam or a straight beam. A segment joint is considered as a rotational
spring and a ring joint is considered as a shear spring.
In addition to above, a system in which the backfill grouting is recently conductedsimultaneously or almost simultaneously with shield advancement, has beendeveloped and the backfill grouting materials which achieve the required strength
at an early stage after driving, have also come to be used. By employing such abackfill grouting system together with circle shape retaining device and using thethrust force of shield jacks properly, the soil reaction acting on the segments is
considered even against the deformation of the segment caused by its self-weight,
which has not been taken into account so far.
3.2 Reduction in tunnel diameter by eliminating secondary lining
Since shield tunnel construction, waterproofing of segmental lining itself andsealing materials have been improved, segmental joint bolts have become lessexposed and the inside surface of a segmental lining have become flat and smooth.
As a result, the secondary lining of the tunnel is eliminated, enabling several
percent reduction of tunnel diameter.
On the other hand, installation of fire-resistant material on the inside surface of atunnel segments shall be planned to prevent spalling of concrete segment fromtunnel fires. Fire-resistant material has been tested and selected according to theGerman Standard, RABT curve. The mortal with fire resistance is sprayed on thesurface of RC segment and panel of silicic acid calcium or ceramics is installed on
the surface the steel segment. Recently, polypropylene fiber (PP, L=12mm,
d=64.8μm, aspect ratio L/d=185), is mixed with concrete to prevent spalling by
getting vapor enter into the void of concrete generated by the melt of PP fiber.
3.3 Development of shield tunnel enlargement method
The innovative technology has been developed to connect main tunnel with ramp
tunnel. As a result, the structures of underground junction and connection between
main and ramp tunnels can be constructed by excavation from the surface with a
cut-and-cover method or trenchless method after main shield tunnels arecompleted.
With development of this method, the distance of a tunnel excavated by one shieldmachine is dramatically increased, and overall construction cost is reduced andthe construction period is shortened. In addition, the adverse effects on surface

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traffic and the surrounding environment can be reduced by minimizing the widthof open excavation. Finally, it would be possible to minimize a risk for delay ofconstruction schedule and reduce environmental impact for surroundings.
4. TUNNEL MANAGEMENT AND OPERATION
4.1 Basic policy for fire prevention and safety measure
The basic policy is that if a fire breaks out, the Metropolitan Expressway Co., Ltd.
will put human life first and give top priority to evacuation, while also preventing
secondary disasters and ensuring the overall safety of expressways throughcooperation with the related organizations. The policy is unique in that it gives
consideration to traffic congestion. The aim is to further improve fire prevention
and safety by taking multifaceted measures from the viewpoints of both facility
planning and management/operation. Such measures include operating roadtransport systems to reduce traffic congestion on a routine basis and operating thesystems in accordance with traffic congestion at the time of fire as well. In orderto further improve safety, it is important to take operational measures on a routine
basis as well as during time of fire. Based on the following considerations, thecomprehensive fire prevention and safety measures shown in Figure 2 will betaken on a routine basis.
- To take measures to prevent accidents, fire and other irregularities on a routine
basis- To take measures to minimize damage to human life and facilities if a fire occurs
in the tunnel as well as to minimize the effects of the fire on society as a whole- To work with users as well as the related organizations, including police,
firefighters and other road administrators, making efforts to prevent disasters
and ensure the safety of the tunnel- To Carry out on a routine basis educational activities and fire prevention drills toprevent accidents and・Appropriate facility placement planning
fires from developing・Comprehensive management/operation
into serious disasters
Measures are being studied
Measures
Circumstances inside tunnel
to provide information on
Traffic control during normal times
Traffic conditions (Congestion,
people evacuation andto decrease congestionetc.)
guidance so that evacuation
Fire conditions (Place,can be completed at an
Fire evaluation of early stage
scale and the like)early stage of the fire. With
Improvement of the evacuation
data
of
the
past
Evacuation environment
environment with ventilation
inside tunnel
experimental fires, traffic
accidents
andother
Traffic control and providing
information for evacuation
irregularities as a reference,
Evacuation
thecharacteristicsof
Evacuation facility
vehicle fires were analyzed
and road tunnel fire
Cooperation with relatedorganizations (Firefighting/rescue
development was classified
activities, etc.)
into early and late stages.
The time targeted to
Figure 2: Basic policy of fire prevention
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will be discussed in 4.2, 4.3 and 4.4.
4.2 Traffic control and management
To ensure safety and comfort on the Tokyo Metropolitan Expressway, traffic
control is in operation on a round-the-clock basis. Patrol services are mustered todeal with accidents in a speedy manner and recover fallen objects. Information
providing services are also offered to expressway users by processing road data
sent at set intervals in real-time. For example, ultrasonic vehicle detectors are
installed at intervals of approximately 300m to collect traffic data. In this manner,traffic volume, speed, and occupancy data are collected and processed in real-time
to assess traffic conditions. The data is displayed or provided on overhead
information panels on the expressway routes and through a roadside radio service.
In addition, a personal information service called VICS provides congestion andrequired travel time information to individual cars via on-board receivers. In
tunnels, CCTV cameras are installed at intervals of about 100m. Images from thecameras are used by the control staff to monitor traffic conditions in tunnels
around the clock. Emergency telephones and other devices are installed so
expressway users can report accidents and other irregularities. In addition,
because of the recent spread of cellular phones it is now possible to report to thecontrol room using the #9910 speed dial number.
In conjunction with the construction of the Shinjuku Route, a new Traffic Control
and Monitoring Center will be built in addition to the existing one. The objective
is to introduce a more advanced and sophisticated system of traffic control. A
typical example is the newly developed system capable of detecting traffic
extraordinary behaviors instantly by processing CCTV images. The introductionof this type of system will help block vehicular access into the tunnel after a
traffic accident has occurred and ensure a smooth flow of traffic through thetunnel. The traffic control system can also be used to prevent traffic jams intunnels to maintain safety and comfort during normal conditions as well.
4.3 Principles governing the safety of users in case of fireIn the event of a fire outbreak, effective fume control must be provided towithdraw fumes and care has to be taken to improve the escape routing.
Appropriate information must be offered to guide people through emergency exit
to safe areas. It is also of great importance to provide safe escape routing rapidly,
the flow of traffic on the opposite tunnel that is not exposed to fire should be
stopped as quickly as possible.
The Shinjuku Route is provided with all emergency facilities laid down bynational regulations. Consideration is being given to the creation and operation offacilities designed to improve the escape routing through the earliest possible
detection of fire outbreak, accurate assessment of the situation, and effective
operation of fume exhaust facilities and to guide people to safer refuge areas. In
addition, a tunnel design is planned to permit rapid access of the firefighting
services to the site of the fire accident. This may include the construction of a U-

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turn lane in the tunnel to permit fast rescue and firefighting operations by thefirefighting services.
4.3.1 Prohibition of access for vehicles with dangerous loads and emergency
equipment
Since the Shinjuku Route is a tunnel of more than 5km in total length, vehicles
carrying dangerous loads such as explosives and gasoline are not allowed foraccess into the tunnel in accordance with the Road Law. Consequently, fire
accidents on the Shinjuku Route can only involve vehicles that do not carrydangerous loads.
Emergency facilities in the tunnel are subject to the “Technical Standard on the
Tunnel Emergency Equipment” by the central government authorities inaccordance with traffic volume and tunnel length. The Shinjuku Route is ranked
as Class AA, requiring the installation of all necessary and adequate emergency
equipment. Figure 3 shows tunnel classification and Table 1 shows emergency
equipment required for Class AA tunnel.
Table 1: Emergency equipment forClass AA tunnel
Warning andalarm equipment

Fire extinguishingequipment
Escape routeguide system
Other equipment

Emergency telephone
Alarm button
Fire detector
Emergency alarm
Traffic signal
Fire extinguisher
Foam hydrant
Emergency Exit
Escape guide panels
Fume exhaust equipment
Water hydrant
Sprinkler
Radio communications
Radio re-broadcasting
CCTV camera
Uninterrupted power supply
Emergency power supply

Figure 3: Tunnel classification
4.3.2 Arrangement of Escape Routes
Emergency exits in the tunnel are spaced at an interval distance sufficient to allow
people to escape safely on foot. There are 39 emergency exits spaced at intervals
no longer than about 350m. There are following three types of emergency exits on
the Shinjuku Route.
1) Center Evacuation Route Type: The inner and outer lanes of sections built by
the open-cut method are designed as an integral structure and five evacuationroutes are to be built in the center of this type of structure.
2) Connecting Tube Type: In the section built by the shield method, where theinner and outer tunnels are separate the two tunnels are to be connected with
10 escape tubes to enable people to escape safely to the oppose tunnel.
3) Independent Stairs Type: Where it is structurally difficult to install evacuationroute or escape connecting tubes, independent escape stairs are to be provided
for access to the ground. These stairs are to be provided in 19 locations. In
section in which shields are constructed in the vertical configuration the upperand lower tunnels are to be connected by escape stairs to be provided in fivelocations.
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will be able to reach the ground safely through escape stairs (provided in 24
locations) installed in the shield construction shafts where the shield machine is to
be started or in the ventilation locations constructed by the open-cut method.
4.4 Safety measures in case of fire
While vehicles carrying dangerous materials are not permitted access to the
Shinjuku and Shinagawa urban long tunnels, their traffic volume are expected toreach 60,000 - 80,000 and 57,000 – 75,000 vehicles a day, respectively, with large
vehicles to make up about 30%. This means that the traffic volume will be very
high and so will the proportion of large vehicles. In view of past traffic conditions
and fire accident patterns, careful and detailed considerations are given to theopinions and experiences of other countries in designing other details of tunnel
structures. In the event of a fire, its earliest possible detection and ascertaining thesituation comes first. It is essential to efficiently extract smoke to improve theevacuation environment, provide appropriate information, and guide evacuees
through emergency exits to a safe space.
4.4.1 Improvement of evacuation environment with ventilation
In the early stage of a fire, ventilation facilities will be operated to maintain anenvironment for evacuating people safely and efficiently. For the Shinjuku andShinagawa Route tunnels, different methods are being devised for operating
ventilation facilities depending on whether there is congestion or not, and specificoperation systems are currently under consideration. In the last phase of a fire, theoperation of ventilation facilities will be switched to support firefighting operation
by firefighting units, and specific operational systems for this stage are also underconsideration. The Shinjuku Route tunnel uses the transversal ventilation system
based on the specially structured flue method while the Shinagawa Route tunnel
uses longitudinal ventilation system with the simplicity of the entire tunnel
structure. Model tests, numerical fire simulations and other experiments wereconducted to confirm whether or not an evacuation environment could bemaintained for around 10 minutes immediately after a fire breaks out, the goal set＜Congestion period＞
Emergency
exit

Upstreamtraffic

Direction ofvehicular traffic

Direction of Direction ofevacuation
wind

Direction ofvehicular traffic

Direction of Direction ofevacuation
wind

Emergency
exit

Vehicle fire
Air supply＜Non-congestion period＞
Emergencyexit

Air exhaust

Air exhaust

Direction ofevacuation

Air supply
Air exhaust

Air exhaust

Emergency
exit

Direction ofwind

Air supply

Vehicle fire

Figure 4: Concept of ventilation operation in case of fire8

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by the Metropolitan Expressway Co., Ltd. The experimental results confirm thatsuch an evacuation environment can be maintained with the scale of ventilation
facilities that is currently planned. (See Figure 4)
4.4.2 Traffic control and providing information for evacuation
Traffic control for the guidance of vehicles involves utilizing entrances and exits
effectively to control traffic for certain sectors with the aim of reducing thenumber of vehicles in the tunnel. The Shinjuku and Shinagawa Route tunnels will
have a large volume of traffic, and therefore, in order to guide vehicles more
precisely, the Metropolitan Expressway Co., Ltd. plans to install traffic block
facilities such as crossing gate, two or more information boards, and signals bothat the entrance of the tunnel and at the point where the tunnel diverges (See Figure5). The ultimate goal of evacuating and guiding people who escape on foot is toguide them up to the ground smoothly and safely, and appropriate ways ofproviding necessary guidance information along the escape route have beenstudied. Measures have been considered on how to guide people to emergency
exits, the most important measures for evacuating them and ensuring their safety,
and how to complete their evacuation in around 10 minutes: the target set by theMetropolitan Expressway Co., Ltd. After a fire is detected, it is important toimmediately provide initial information of fire to all people in the tunnel in order
to direct their attention to the event. After that, information on fire will be
provided to people inside the car through repeated radio broadcasts and to those
who are outside the car through public address systems. The evacuation andguidance policy is to provide people with information in two ways: providing
visual information by installing guidance lamps pointing to emergency exits andproviding auditory information by using public address systems.
Information board

Traffic block bar
Through the traffic
Fire point

Information board

Exit

Figure 5: Traffic control equipment at the diverging point in the tunnel
4.4.3 Cooperation with related organizations
Since cooperation with related organizations such as firefighting authorities isimportant to prevent secondary disasters and check the spread of fire, the roadadministrator has devised policies on supporting such organizations. The Shinjuku
and Shinagawa Route tunnels exist in urban areas, and therefore, fire stations arelocated relatively close to the route and the time required for firefighters to rush to
the scene is not a major problem. It is necessary, however, that firefighters choose
an efficient and safe route since the Shinjuku Route tunnel has many entrancesand exits. It is of utmost importance to communicate accurate information to firestations quickly, and plans call for direct telephone lines to be installed and visual
images provided by cameras to be exchanged so that the control room cancommunicate with fire stations easily.
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5. CONCLUSION
This paper has described the innovative technologies for the construction oftunnel structures in urban areas, and integrated management and operation system
for long urban tunnel to secure safety and prevent disasters.
Based on the results in this paper, the following conclusions can be drawn.











In order to achieve an efficient operation of traffic network in the Tokyo
Metropolitan area, it is essential to develop the circular route.
Since the Central Circular Shinjuku and Shinagawa Routes are located inhighly densely populated city, it is essential to construct these routes
underground to accommodate the need for minimizing the environmental
impact and complete the routes in a short period.
These underground projects provide a realistic prospect and sustainable
development for reducing construction costs through the use of innovative
construction technologies such as a large diameter of shield tunnel and shieldtunnel enlargement method which has been newly developed by theMetropolitan Expressway Co., Ltd.
Safety measures to be taken at the time of fire are being developed with use of
the latest knowledge and the overall direction of safety measures is being
determined.
The rapid collection of data and providing information by using traffic control
and monitoring systems, and road and traffic control, including restriction ofaccess into the tunnel, will also be an important factor in terms of upgrading
service and safety.
Safety of the Shinjuku and Shinagawa Route tunnels are an important criterion.
In view of this, efforts will be made to develop the facilities, tunnel structures
and their operation taking account of the latest opinions and studies.
Considerations described in this paper will contribute to the urban safety of
the underground space in mega cities such as Tokyo Metropolitan area.

REFERENCES
Furuki, M., Ando K. and Kurohara, I., 2001. Planning a long urban tunnel -project
outline of the Tokyo Metropolitan Expressway Central Circular Shinjuku Route-,
1st World Conference on Urban Road Tunnel, 14th World Congress of theInternational Road Federation (IRF), Paris.
Hamabe, K., Kikkawa, H., Tajima, H., and Tazawa, S., 2005. Safety measures offire prevention in long urban tunnels –Tokyo Metropolitan Expressway Central
Circular Shinjuku Route-, 15th International Road Federation (IRF) World
Meeting, Bangkok.
Ando, K., Ishii, N. and Dobashi, H., 2004. Construction of the Metropolitan
Expressway Central Circular Route, which supports Tokyo Metropolis, The Third
Civil Engineering Conference in the Asian Region(CECAR), Seoul.
Dobashi, H. 2012, Soil improvement for extra soft ground of offshore reclaimed
land and advanced technology for tunnel construction, International Symposium‘Developing bridge and road construction technology in Viet Nam’ VIBRA-MOT,
Hanoi.

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The structural design trend of
supertall buildings in Vietnam
1

Phan Quang MINH1, Pham Thanh TUNG2
Professor, Dean, National University of Civil Engineering,Vietnam
minhpq@nuce.edu.vn
2Dr., National University of Civil Engineering,Vietnam
ptunguce@yahoo.com

ABSTRACTThis paper describes the tendency of the structural design of supertall buildings in
Vietnam. Reference is made to four projects in Hanoi and Ho Chi Minh City.
Besides, typhoon, inducing a huge wind load on high-rise buildings, is required tobe rigorously considered. The wind tunnel test is applied to determine the impact
of typhoon and then the obtained data are used to design both architectural andstructural systems of the mentioned above buildings.
Keywords: supertall building, structural system, wind tunnel test
1. INTRODUCTION
Due to the high growth in population and businesses in Vietnam, the demand of
supertall buildings has been rapidly increasing. As CTBUH (2012), the Keangnam
Landmark Tower, the tallest building in Vietnam, is in Top 100 tallest completedbuildings all over the world (38th). A successful design of a building is anachievement of a mutual collaboration among of the architect and the engineer tofind out an appropriate architectural and effective structural system. However,difference from the design work of low-rise buildings is the more challenges
designers have to deal with high load-bearing foundation, vertical and horizontal
structures to make the high-rise building sustain under the more sophisticatedlateral load as wind load and the complexity of the mechanical systems: fire
distinguisher, vertical transport and human evacuation.
Selecting the structural system has a great impact on both exterior aesthetics andits interior space planning of a building. In this paper, the structural systems offour tallest buildings, mentioned in Table 1, are analyzed to introduce the trend oftall building design in Vietnam.
Table 1: Vietnam’s 4 Tallest Building (up to 2013)
Building
Bitexco Tower
KeangnamLandmark Tower
Lotte
CenterTower
Vietinbank Tower

City

HeightFloorsYear

Ho Chi Minh
City

269 m

68

2010

Hanoi

336 m

72

2011

Hanoi
Hanoi

267 m
362 m

65
68

2013 (roofing)under construction

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VietnamBitexcoFinancial
Tower

KeangnamLandmark
Tower

Lotte Center Tower

Vietinbank Tower

Fig. 1.Four Tallest Buildings in Vietnam (up to 2013)
Besides, the decision of architects on the geometry of the floor plan not only
impact upon the interior space planning, exterior building envelope but also to thestructural design. Generally, the simpler and more regular the floor plan shape, theeasier the demand of the user in floor partitioning is satisfied. Square, rectangularand round floor plans have shown the more efficiency than curved and irregularshapes. The efficiency is based on the ratio of the usable to gross area of a floor(Paul H K HO, 2007). Among of four buildings in the paper, The Vietinbank
Tower is an example with the V- shaped plan and other three buildings are withsmooth and round plan shapes. For these projects, the ratio is about 70 to 80 %.
2. FOUNDATIONS
A well-designed foundation is an important part of a high-rise structure because
its function is to safely transfer the structural loads from the building to theground. Successful geotechnical engineering remains hidden underground and theimportance of a good foundation only becomes visible when errors occur. The
foundation is evaluated based on the criteria of allowable settlements, tilting andbuilding damage.
The reinforced concrete mat supported on bored piles was applied for thefoundation system of the four projects. For example, the mat foundation of Lotte
Project with the dimensions of 92.7 m(W) x 44.1 m(D) x5.7 m(H) was
continuously cast in situ in 52 hours. On basis of aforementioned project data, thesystem is the most practical and economical option.
In Vietnam, the two-level basement is fairly popular but the studied projects havemore than 4 underground floors. That required a rigid perimeter diaphragm wallconstructed by the slurry method

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Bored piles with a wide range of diameter and length based on their design loadbearing capacity are appropriately applied for tall buildings. At the Bitexco Tower,
1500mm diameter bored piles extending to a depth of between 80m to 90m wereconstructed under the main load-bearing structures, while the podium andbasements were supported by bored piles with 1200mm in diameter and 63m inlength (Figure 2). At the Vietinbank Tower, bored piles were 2000 mm indiameter, which extended to the depth of about 45 m from the ground surface withthe observed load-bearing capacity of 35000kN, so far from limit capacity
predicted by the Vietnamese Code.

Figure 2.The Bitexco Tower’s pile arrangement
3. MATERIALS AND SUPERTALL BUILDINGSThe selection of construction materials may be dependent on the height andfunction of a building. Each construction material has its own limitations in termsof mechanical properties and economical feasibility. The total structural material
quantity and its cost have always been an important determinant for thedevelopment of super tall buildings. The structural efficiency can be measured bymeans of the lowest total construction cost which may be minimized by (1) using
local materials and laborers, (2) optimizing the sizes of structural members so as
to increase the usable/rentable floor area and thus its future revenue, (3) reducing
the structural weight so as to reduce its impact on the foundation, and (4)shortening the overall construction time so as to generate income earlier and also

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Vietnamreduce the loan expense. In Vietnam, concrete and steel are two dominantmaterials used to build tall buildings.
3.1. Concrete
In supertall buildings floor slabs and beams can be made of light weight or normal
concrete which reduce their self-weight. The columns are normal or high strength
concrete because they are the main load-bearing structures. High strength concrete
is highly recommended for high-rise buildings due to high strength and durability.
According to the European Norm EN 206-1, high strength concrete is defined asconcrete with a strength class above C50 grade equal to B60 in Vietnamese CodeTCVN 5574-2012. High strength concrete mix requires strictly quality control onsite and is more expensive than normal strength concrete due to the requirementof high cement content and admixtures.
High-strength concrete has not been very common in Vietnam yet, but it was used
for all abovementioned above projects with maximum grade of 70 MPa (cylinder).
Concrete grades used for The Keangnam Landmark Tower and The Lotte Tower
are shown in Table 2 and 3.
Table 2: Concrete strength in The Keangnam Landmark Tower
KeangnamLandmark Tower

Residental Tower (50fls)
Concrete grade

Hotel Tower (72fls)
Concrete grade

Shear walls,
columns, beams

23F↓ 70 MPa
24F↑ 50 MPa

PT slab23F↓ 50 MPa
24F↑ 45 MPa

27F↓ 70 MPa
47F↓ 60 MPa
48F↑ 50 MPa
27F↓ 50 MPa
47F↓ 45 MPa
48F↑ 35 MPa

Table 3: Concrete strength in The Lotte Tower
Tower (65fls)
Concrete grade

Lotte Tower
Shear walls, columns,
link beams
Beams, slab

34F↓ 60 MPa
41F↓ 50 MPa
42F↑ 40 MPa
34F↓ 43 MPa
41F↓ 40 MPa
42F↑ 30 MPa

3.2. Steel:
In Vietnam market, there are limited suppliers for quality structural steel andexperienced contractors in steel fabrication. Using steel material to constructbuildings is normally more expensive than reinforced concrete, when taking
account of the additional fire protection cost for structural steel members.

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For the Vietinbank Office Tower, a mixed system comprised of structural steel
floor framing, perimeter composite columns and concrete core wall was employed(Figure 4). The structural steel grades for rolled shapes are to be as follows: wide
flanges: ASTM A992 (fy = 350 MPa), other rolled shapes: ASTM A36 (fy = 250MPa), built-up shapes: ASTM A572 (fy = 345 MPa).
4. STRUCTURAL SYSTEMS OF TALL BUILDINGSIn addition to transferring the gravity loads to the foundation, another importantrole of the structural system in a tall building is to resist the lateral loads caused
by wind or earthquake. Therefore, main structural systems of tall buildings areclassified mostly based on their relative effectiveness in lateral load resistance.
Another classification of structural systems of tall buildings is on basis of theposition of the dominant lateral load-resisting system at the floor plan including
two broad categories: interior structures and exterior structures (Mir M. Ali andKyoung Sun Moon, 2007). A system is categorized as an interior structure inwhich the major part of the lateral load resisting system is located within theinterior of the building while in an exterior system if the main lateral load-bearing
system is set on the perimeter of the building.
4.1. Interior Structures
The interior structure category consists of two fundamental types as the momentresisting frames and shear trusses/shear walls. These systems are assembled by agroup of planar structures developed in two orthogonal directions. These planar
structures interact to form the spatial stiffness of the building to resist the lateralloads.
A derivation of this category is the core-supported outrigger structure, which is
widely used for supertall buildings. Outrigger systems have been historically usedby sailing ships to help resist the wind forces in their sails, making the tall andslender masts stable and strong. The core in a tall building is analogous to themast of the ship, with outriggers acting as the spreaders and the exterior columns
like the stays. As for the sailing ships, outriggers serve to reduce the overturning
moment in the core that would otherwise act as pure cantilever, and to transfer the
reduced moment to the outer columns through the outriggers connecting the coreto these columns. The core may be centrally located with outriggers extending on
both sides or in some cases it may be located on one side of the building withoutriggers extending to the building columns on the other side (Taranath, 1998).
In comparison with the tube system which requires diagonals or closely spaced
columns, the advantage of the core-outrigger system is that the exterior column
spacing can easily meet aesthetic and functional requirements and the buildings
perimeter framing system may consist of simple beam-column framing without
the need for rigid-frame-type connections. For supertall buildings, connecting theoutriggers with exterior megacolumns opens up the facade system more flexible,
aesthetic and architectural articulation.
This system has a disadvantage is that the outriggers can interfere with theresidential or rentable space and makes the erection process slower due to the lackof the structure unity. Nevertheless, these drawbacks can be overcome by

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Vietnamarchitectural and structural solutions such as placing outriggers in mechanicalfloors and improving erection procedure.
The outrigger systems may be formed in any combination of steel, concrete andcomposite construction. Most of the supertall buildings in Vietnam such as The
Keangnam Landmark Tower, The Lotte Tower and The Bitexco Tower have used
the system as the main load-bearing structures. Figure 3 shows the structural
system of The Keangnam Landmark Tower with details of the outrigger trusses
and belt trusses at the floor 23rd (Byung-Ick Yoon et al., 2010).

Figure.3. Structural system of Keangnam Landmark Tower
In The Bitexco Tower, for wind load design, the outrigger trusses and belt walls
were connected to the core walls and perimeter columns from the floor 29th to 30th.
This allows the outrigger and belt wall systems to collaborate with the concretecore walls in resisting lateral loads. To construct the outrigger system, two of thefour sets of double-story trusses was set aligned with the two primary core crosswalls and the other two trusses was put parallel to the fire stair walls. The
connections between the outrigger trusses (1000mm wide) and the cross walls(400mm) is considered to effectively transfer lateral forces (William J. F., 2009).
4.2. Exterior Structures
The exterior structure of the building is supposed to absorb a great proportion oflateral forces especially wind loads. Hence it should be noted that most of thewind resisting system is concentrated on the perimeter of tall buildings. One of
the most typical exterior structures is the tubular, which consists of a great

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number of rigid joints, acting along the periphery, creating a large tube. In
framed tube system, the exterior tube carries all the lateral loads and the gravity
load is supported by the tube and the interior columns or walls. The columns
connected by a deep spandrel are closely packed on the perimeter of the building.
In braced tube system instead of using closely spaced perimeter columns, widely
spaced columns stiffened by diagonal braces are applied. Another structural
system can be formed by clustering the individual tubes. In the system, the tubes
are interconnected by common interior panels to generate a perforated multi-celltube.
A super-frame system is composed of megacolumns combining with braced
frames of large dimensions at building corners. The systems are linked bymultistory trusses at about every 15 to 20 stories. The designers have been usedthe concept of super-frame for The Vietinbank Tower. The structural layout at
level 5, 27 and 48 of the tower is shown in Figure 4.

Figure 4. Structural Plan Layout of The Vietinbank Tower at level 5, 27 and 48
As mentioned above, the core-outrigger structures and the megacolumns are going
to be dominantly used as the main structural system for supertall buildings. The
combination of these systems should be studied to apply in Vietnam in the near
future.

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4.3. Floors
In terms of structural roles, the floor system is to sustain the self-weighted loadand constructing loads in and after erection. This also works as a diaphragm totransfer and redistribute the lateral loads to vertical structural components such as:
shear walls, cores, tubes...
When it comes to the service duration of the building, the floor system is used todivide the building space in the vertical direction. It plays a role as an anti fire
spreading and sonic insulation components. The floor also carries the mechanicalsystem of the building such as the heating, ventilating and air conditioning
systems.
The floor makes up a large portion of the self-weight of the whole building so thatthe selection of floor system types is really important and greatly influences on
the construction cost. In situ concrete floor is very reliable and economical due tothe development of concrete pumping technology. This type of floor creates avery stiff diaphragm and effective in terms of transverse load transferring. Precast
concrete floor has an advantage because of shortening the construction duration
but the requirement of the large crane work makes it more expensive.
4.3.1. Flat slab floor
A flat-slab floor, with the span from 8.5 to 9.5 m, has the thickness from 280
to320 mm. The self-weight of these flat slabs significantly increases the total
weight of the structure system.
In The Bitexco Tower, the conventional slab with the thickness of 250mm wasconstructed for the lower office floors while the upper office floors used the 250
mm thick flat slab system.
In The Vietinbank Tower, the conventional slab with the thickness of 250mm wasconstructed for the lower office floors while the upper office floors used the 250
mm thick flat slab system.
The flat slab system with the span of 9m combined with the perimeter spandrel
beams were employed for The Lotte Tower.
4.3.2. Prestressed concrete floors
Prestressed concrete is an advance technology for long span slabs. The technology
is effective when the span of the slab is over 9 m due to the reduction of the
thickness. The thickness of the prestressed concrete slab is only about 1/40 of the
span length. In The Keangnam Landmark Towers, the PT slab was used as areplacement for the conventional slab system.
4.3.3. Composite floors
A composite floor is a combination of different materials to develop an economic
structural system. Steel and concrete composite floors are fairly popular in tallbuilding. To form the composite slab, in situ or precast concrete can be used. The
link between two materials is founded by welding shear connector, called shear
studs, which is welded to the steel decking and buried on concrete after hardening.
The use of composite slab and cast in place concrete beam form an effective
system. This was employed by The Steel Deck to design the slab of The

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Vietinbank Tower. The slab was 75mm deep galvanized composite deck per
ASTM A653 with a minimum yield strength fy= 280 MPa (Figure 4).
5. WIND TUNNEL TESTING
The impact of the winds can be reduced by aerodynamic effects based on the
optimization of the shape of the buildings. The building has to design so that thehigher stiffness of building s is to resist the dominant wind. To achieve that goal
the wind tunnel test is required. The data obtained from the test not only is used todesign the structural components including columns, beams, bracing frames andfoundation but also to select the façade systems. The wind tunnel test is more
effective when the building is taller because this helps to collect the more accurate
wind load on the structures. For the high-rise buildings, the serviceability limit
state related to wind loading, sometimes, is more concerned than the ultimate limit
state.
Vietnam is located in an area where typhoon appears frequently. It is important tostudy wind climate in Vietnam in order to accurately estimate impact of the wind
to the structure and the building’s behaviour as well. At the moment, theapplication of the wind tunnel test for determining the wind load for tall building
is not popular and only applied for four abovementioned projects in Vietnam. We
will consider the wind tunnel test of The Vietinbank Tower as an illustration ofusing experimental data in designing work (RWDI, 2011).
A 1:500 scaled model of the tower was set up based on the architectural drawings(Figure 5). 997 pressure tags were mounted on the model to measure the windpressure. All surroundings within 600m from the centre of the building wasmodeled to estimate the interaction between the building and the topography.
Beyond the modeled area, the influence of the upwind terrain of the planetary
boundary layer was simulated in the testing by appropriate roughness on the windtunnel floor and flow conditioning spires at the upwind end of the working section
for each direction.
The wind pressure impacting on the building is a function of the return period. Inorder to predict the pressure, the wind tunnel data were combined with a statisticalmodel of the local wind climate. The wind climate model was based on measuringlocal surface wind and simulating local typhoon on the computer at Noi Bai
International Airport (Hanoi). Over 100,000 years of tropical storms were
simulated to account for variability of typhoon wind speed within direction. The
wind climate model was scaled so that the magnitude of the wind velocity for the
50-year return period corresponding to 3-second gust wind speed was 43.2 m/s ata height 10m on the open terrain, equal to a reference pressure of 11.4 kPa. This50-year reference pressure was obtained by the application of a reliability factorof 1.2 to the code referenced 20-year pressure of 950 kPa. This value is consistent
with that defined for Hanoi area in the Vietnamese Standard TCVN 2737:1995.
The wind load on the cladding system of these projects was obtained from thewind tunnel test data.
The wind pressures obtained from wind tunnel tests would be lower than code
predictions due to the unconventional geometry of buildings, the complexity ofthe surroundings as well as the wind directionality. However, the changes of thesurroundings in the near future need to be controlled and concerned. By that way,
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Figure. 5. The wind tunnel test model of The Vietinbank Tower
CONCLUSION
The appearance of supertall buildings is essential for the big cities of Vietnam sothat their designs are rigorously concerned by engineers. Presently, the coreoutrigger system is widely used for the load-bearing structure of the buildings.
Together with the development of concrete technology, high strength concrete isused as a solution to reduce the construction cost for the type of buildings.
Moreover, to obtain the accurate wind load on the supertall buildings, the windtunnel tests are employed. The effectiveness of these applications has been provenbased on the analysis data of the four reference projects in Vietnam.
REFERENCES
Byung-Ick Yoon et al., 2010. Design and Construction of Keangnam Hanoi
Landmark Tower in Vietnam, Journal of the Korea Concrete Institute, vol. 22,
issue 2 (in korea).
CTBUH, 2012. 100 tallest completed buidings in the world. CTBUH. Retrieved
27 April 2012.
Mir M. Ali and Kyoung Sun Moon, 2007. Structural Developments in Tall
Buildings: Current Trends and Future Prospects. Architectural Science Review,
volume 50.3, pp 205-223.
Paul H K HO, 2007. Economics Planning of Super Tall Buildings in Asia Pacific
Cities. TS 4G - Construction Economics and Development.
Taranath, B.S., 1998. Steel, Concrete and Composite Design of Tall Buildings,
McGraw-Hill, New York.

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RWDI, 2011. Head office of Vietinbank, Draft Final Report. Wind- Induced
Structural Responses.
William J. F. et al. , 2009. Bitexco-Finacial Tower. Structure Magazine, June.

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Utilization of unused and/or non-familiar
materials for construction
Taketo UOMOTO
Chief Executive,
Public Works Research Institute
Professor Emeritus, University of Tokyo
ABSTRACT
Considering the sustainability of structures, it is important to utilize unused
and/or non-familiar materials for construction. In most cases, when theregulations and specifications are used, engineers do not think much about theusage of unused and/or non-familiar materials. It is convenient for the engineers
to use familiar materials than unused and/or non-familiar materials. As a result,the engineers construct similar structures without considering the cost andsustainability of the structure. This paper shows an example of constructing alarge dam utilizing unused material (CSG) in Japan. The result shows thatutilization of unused and/or non-familiar material may give a new way to the
future.
Keywords: utilization, unused material, non-familiar material, CSG, dam
1. INTRODUCTION
In the year 2011, a huge Earthquake occurred on March 11, in the north easternpart of Honshu Island. Not only the earthquake, but also the great tsunami hit theEast coast of Honshu Island. Due to the tsunami, many houses and structures on
the coastal lines were destroyed completely. As a result, tremendous amount ofdestroyed materials, including wood, concrete, steel, mud, stones, bricks, etc.,
were damped on the land of Tohoku area It takes about three years to clean up
the land from these deposits.

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The next problem is how to utilize these deposits: it is difficult to utilize them asconstruction materials in normal manner. Even after they are separated to sand,stones, bricks, wood, etc., they contain various small sized materials with salt, etc.
They cannot meet the requirements of standards of any country to be used as
normal construction materials, such as for concrete.
To deal with the problem, one method may be to utilize these material as unusedmaterial or non-familiar materials for construction. If they are used as
construction materials, we can utilize them to rebuild the structures and land ofdestroyed area. This paper gives an example of utilizing unused material
including river deposits as CSG (Cemented Sand and Aggregate) for dam
construction in Japan. For those who have more interest on the technology, thedetails are given in the following paper: Kenji Sakata: Current Situation ofPlanning and Construction of Dams in Japan, Foro International de Concreto
20122).
2. TRAPEZOIDAL CSG DAM
The trapezoidal CSG dam1) is a new type of dam which differs from theconventional concrete gravity dams and embankment dams, and its dam body istrapezoidal in shape and made of cemented sand and gravel (CSG). In Japan inparticular, the quarry conditions of yield ratio and transport required to obtain dam
body materials are becoming more severe, with aggregate related costs accounting
for approximately 40% of total work costs at recently constructed concrete dams.
There is thus an urgent need to rationalize material-use to cut costs and reduce theenvironmental load imposed by excavated slopes, etc. The trapezoidal CSG dam
is a new type of dam which can be realize rationalization of materials, which iscurrently the biggest challenge to be overcome, and also helps to rationalize thedesign and execution.

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A trapezoidal CSG dam is a trapezoidal shaped dam built using CSG by the CSG
method, and has the following characteristics.
[1]
Rationalization of materials
The dam body of a trapezoidal CSG dam requires less strength, so thematerial strength may be low, permitting the use of low-quality materials andexpanding the range of materials which can be selected.
[2]
Rationalization of design
In addition to the lower strength required for the dam body material, a
trapezoidal CSG dam has fewer requirements for the foundation bedrock,increasing the flexibility for dam site selection.
[3]
Rationalization of execution
A trapezoidal CSG dam can be built with a simple material manufacturing plant,
permitting rapid execution by a continuous mixing system.
Figure 2 shows the standard cross section of trapezoidal CSG dam. A trapezoidal
CSG dam is made using CSG for the main part of dam body, and protection
concrete is placed on its surface to secure durability and water-tightness. A gallery,structural concrete and a seepage control concrete for securing an appropriate
seepage pass length are placed on the upstream side. The CSG on the bottom
surface of the dam body is rich-mix CSG prepared to ensure durability. The
trapezoidal CSG dam is designed in range of an elastic body behavior, so like aconcrete dam, the discharge systems, gallery, etc. can be placed inside the dam
body, and the emergency spillway, etc. placed at the crest.

Protection concrete
Protection concrete
Structural concrete

CSG

Gallery
Seepage
Seepagecontrolcontrol
concrete concreteRich mix CSG
Foundation drain hole
Auxiliary curtain grouting
Curtain grouting

Figure 2 Standard cross-section of a trapezoidal CSG dam 1)
The differences between a trapezoidal CSG dam and a concrete gravity dam,which are designed as an elastic body, are summarized below. Table 1 explains thebasic differences in design, and Figure 3 shows differences in the designing
procedures for the two kinds.
CSG is produced using simple equipment by mixing cement and water withmaterial obtainable nearby without classification, gradation adjustment or
Utilization ofUtilization
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non-familiar
materials formaterials
constructionof unused
and/or non-familiar
for construction25

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamwashing. The CSG method involves spreading CSG with bulldozers, thencompacting it with vibrating rollers to build the structure. This method reduces
costs, speeds up execution, and reduces the impact on the environment. Figure 4
illustrate CSG manufacturing process, Figure 5 shows an example of CSG mixing
facility and Figure 6 shows situation of CSG casting.
Table 1 Differences between designs 1)

Trapezoidal CSG dam- It is not necessary to integrate the dam body andBasic differences
foundation bedrockin design- The dam body volume is larger
The vertical stress at dam bottom surface is
Resistance against compressive, even during an earthquake, over theentire region.
overturning

Concrete gravity dam- It is necessary to integrate the dam body with thefoundation bedrock- It is possible to minimize the dam body volume
During an earthquake, tensile stress is occurred on
dam bottom surface, and its tensile stress is
resisted by integrating the dam body with thefoundation.
Friction between the dam body and bedrock can Sliding safety is secured by integrating the dam
Resistance against
fully resist sliding.
body with the foundation bedrock to use the shear
overturning
strength of the bedrock.

Trapezoidal CSG dam(Dam body designing in accordance withmaterial strength)[1] Study of engineering properties ofmaterials obtainable nearby↓[2] Study of design and execution suited tothe materials
Concrete gravity dam(Dam body designing for minimization of dam
volume)[1] Design of dam body (basically, aright-triangle)↓[2] Ensuring good-quality materials suitable
for the design

Materials, design,and execution arecloselyinterrelated.
Designproceduresare different.
The dam body
shape is designed
first, then materials
are selected tosatisfy its
conditions.

Figure 3 Design procedure 1)
CementRaw Material

Water

CSG

CSG Material

Removing over-sizedmaterials

Placing/CuringMixingFigure 4 CSG manufacturing process 1)

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Primary stock

Cement / watersupply system

Secondary stock

Bulldozer
Wheel loader

Bulldozer

Mixer

BackhoeDump truck

Figure 5 Example of CSG mixing facility 1)

Figure 6 Casting of CSG
3. EXAMPLES OF CSG DAMS
The first structure made of CSG and by a method using this material, the CSG
method, in Japan was the upstream cofferdam at the Nagashima Dam. Since then,
CSG and the CSG method have been used to build many upstream cofferdams andother temporary structures such as embankment work for roads, etc., because it iseasy both to obtain the materials and to execute the method. In response to thisdemand, and with accumulated knowledge of the physical properties andexecution characteristics of CSG and the CSG method, work began in 1999 on
developing a dam design applying a trapezoidal shaped cross section and using
CSG, and the proposed design method was completed the following year.
CSG, which can be produced easily by mixing cement and water with material
obtained nearby without gradation adjustment and washing, is not as strong as
concrete. To overcome this shortcoming, it was combined with a trapezoidal dam
shape, which does not require great strength. The newly developed trapezoidal
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CSG dam design method was applied to design the seepage control structure (damvolume 34,000 m3, height 30 m, Okinawa General Bureau (OGB)) at the Taiho
Dam and the Kawai Sub-dam (dam volume 32,000m3, height 14m, MLIT) of the
Haizuka Dam, and both were constructed by the CSG method. Based on theseresults, the “Engineering Manual for Construction and Quality Control ofTrapezoidal CSG Dams (September 2007)” was compiled as the basis forconstructing a full-scale dam. As full-scale trapezoidal CSG dams, placing of the
body of the Tobetsu Dam (dam volume 813,000m3, height 30m, Hokkaido) and of
the sub-dam of Kasegawa Dam (dam volume 68,000m3, height 30m, MLIT)
began in 2009, and placing of the body of the Okukubi Dam (dam volume339,000m3, height 39m, OGB) began in 2010. At all those dams, CSG casting
completed within one year. Figures 7 and Figures 8 show Tobetsu Dam andOkukubi Dam, respectively.

Figure 7 Tobetsu dam

Figure 8 Okukubi dam
4. UTILIZATION OF UNUSED AND/OR NON-FAMILIAR MATERIAL
It is difficult to utilize unused and/or non-familiar materials as usual construction
material. Even the most familiar construction material; “concrete” has been usedand studied for more than 200 years but yet we still encounter many problems. It

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takes a long period of time to utilize new materials for construction consideringboth strength and durability aspects of a material, but if we can develop a new
method to utilize unused and/or non-familiar materials, we can get a new method
even for the newest constructions.
The important point for such utilization is that we have to consider not only theproperties of concrete, but also the concept of designing a structure using the newmaterial. In some cases, we have to develop technologies to maintain the qualityof the material and develop a new construction method using the material.
Considering the sustainability of structures on earth, it will become an important
issue to utilize unused and/or non-familiar materials when a large scale disaster
happens in the world. I hope we can develop the method in the near future.

REFERENCES
1) The Technical Committee on Engineering Manual For Construction andQuality Control of Trapezoidal CSG Dam: Engineering Manual for
Construction and Quality Control of Trapezoidal CSG Dam, Japan Dam
Engineering Center, September 2007.
2) Kenji Sakata: Current Situation of Planning and Construction of Dams in Japan,
Foro International de Concreto 2012.

Utilization ofUtilization
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non-familiar
materials formaterials
constructionof unused
and/or non-familiar
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Water management in Vietnamese cities:
present status and vision to future
Viet Anh NGUYEN
Associate Professor and Vice Director, Institute of Environmental Science andEngineering (IESE), National University of Civil Engineering, Vietnam.
vietanhctn@gmail.com
ABSTRACT
Water is a crucial component for life in any city. The water issue is often
becoming more and more crucial in fast growing megacities. Adequate
distribution of water among users ensuring water source protection is among
most crucial issues in Vietnamese urban water supply. Besides, other hot issues inurban water are analyzed in the paper. Further, analyzing current status andevolution trend in the last 20 years of wastewater management, the author
proposes recommendations aiming at sustainable urban water management in
Vietnamese urban areas, such as, establishment of a National Strategy and a
National Target Program on urban water management, whereas River basin
management approach should be realized; increase of wastewater tariff toachieve O&M cost recovery and system sustainability; encouragement of PublicPrivate Partnerships (PPP) and Private Sector Participation (PSP) in the sector;
implementation of Sanitation planning on a citywide or river basin wide basis;
application of combination of centralized scheme for dense core urban areas, anddecentralized scheme in the remaining parts; implementation of sustainable flood
management solutions in combination with selection of appropriate wastewatercollection and treatment options; integrated treatment of different waste fractions
for resource recovery in the cities.
Keywords: water supply, wastewater, collection, treatment, resource.
1. URBAN WATER SUPPLY
Water is a crucial component for life in any city. The water issue is often
becoming more and more crucial in fast growing megacities. Up to June 2013,
there are 765 cities and towns in Vietnam providing residence for more than 32%
total population of the country. The total design capacity of urban water supply
systems is about 6.5 million m3/day, whereas actual operation capacity of them is
5.7 million m3/day or 89% of the design capacity. The average ratio of urban
population served with centralized water supply systems is 77% or 32.6 million
persons. This ratio is ranging from 57% as average for grade V towns, to 80% for
cities and towns of grade IV and larger. Non-revenue water is still as high as
27.8 %, ranging from 7.2 to 44.9% from company to company. An average water
consumption rate is 101 l/cap/day, ranging from 33 to 213 l/cap/day (Figure 1).
Average energy consumption for each cubic meter of water produced is 0.35
KWl/m3, ranging from 0.18 to 1.0 KWh/m3. Cost for energy in average is 26.3%,31

October
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Vietnam
October
2013, Hanoi,
Vietnamranging from 4.2% to 47.6% of total water system operation and maintenancecosts.
Adequate distribution of water among users ensuring water source protection isamong most crucial issues in Vietnamese urban water supply. Master plans forurban and industrial water supply for core development zones in Vietnam areunder development and revision. Other key issues in urban water supply in
Vietnam include: (1) Surface water scarcity, salt intrusion, usage conflict; (2)Groundwater depletion; (3) Non-revenue water: (4) Water pollution (NOMs,
industrial chemicals, pathogens, chlorine disinfection, … in surface water, organicand nitrogen compounds, arsenic, salt intrusion, … in ground water); (5) Poor
O&M capacity especially at peri-urban and rural water supply systems; (6) Needin process optimization, energy savings, efficient management; (7) Privatization,
self financing capacity and cost recovery at water utilities.

Figure 1. Average water consumption in urban households from 6 regions in
Vietnam(Source: MOC – WB. Urban water sector database, 2013)
2. URBAN WASTEWATER MANAGEMENTOver last three decades, a legal framework in environmental protection, urban andrural infrastructure development in general, and in sanitation or wastewater
management in particular has been making significant steps forward. The first
Environment Protection Law has been issued in 1995, and its Revision has been
issued in 2005. Since 1998, the Government of Vietnam has initiated policies andprovided investment to improve urban sanitation resulting in significant progressin development of the wastewater sector. Provision of wastewater services to theurban poor has been impressive with open defecation now eliminated.
Environmental Protection Fee imposed to urban and industrial wastewater has
been taken in force in 2003. Important Decrees on Urban and Industrial Water
Supply, Wastewater Management, and Solid Waste Management have been
issued in 2007. The third National Target Program on Rural water Supply andSanitation (NTP3) implemented in the period 2011 – 2015 pays more focus on
sanitation improvement activities (see Figure 2). Effluent standards for different
types of wastewater are being set up. However, number of efforts is required in

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order to make Vietnamese wastewater related legislations more practical andefficient. Access to toilets is now 94%, with 90% of households using septic tanks
as a means of on-site treatment. 60% of households dispose of wastewater to a
public sewerage system, primarily comprising combined systems. By September
2013, some 20 urban wastewater systems had been constructed in Hanoi, Ho Chi
Minh City and other provincial towns and cities, with a total capacity of 600.000
m3/day (Figure 3). Besides, some 30 new wastewater systems are in thedesign/construction phase.

Figure 2. Timeline of development of wastewater management activities inVietnamFigure 3. Functioning wastewater treatment plants in Vietnamese urban areas

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Despite these impressive initiatives, urban sanitation continues to face criticalissues that need to be urgently addressed as follows: (1) Most of urban sewerageand drainage systems are combined (Figure 3), with low household connection
rates (especially in low density urban and peri-urban areas and in urban areas ofcentral region where soil is mostly sandy), and whereas only 10% of wastewater isbeing treated; (2) Only 4% of septage is treated. Fecal sludge management isgenerally poor in most cities; (3) Cost recovery of the capital and O&M costs of
the wastewater systems are generally low (Figure 4); (4) Institutionalarrangements do not encourage efficient system operation with the wastewater
enterprises having limited autonomy to manage operations and undertake systemdevelopment; (5) Financing needs are still very high, estimated to be USD 8.3
billion to provide sewerage to the estimated 2025 urban population of 36 million;(6) Lack of understanding by decision makers of appropriate technical solutions
and the limited land available for the WWTPs has resulted in construction of
expensive treatment facilities with advanced technology and imbalance withhousehold connection and network investment; (7) Integrated, river basin
management concept is not applied; (8) Urban sanitation planning is not being
included properly in master urban planning and planning of other development
plans; (9) Limited participation of private sector in urban wastewater management
activities.

Figure 4. Urban sewerage connections against city GDP per capita(Source: EAP Sanitation review, WB, 2013)
3. RECOMMENDATIONS FOR SUSTAINABLE
MANAGEMENT IN VIETNAMESE URBAN AREAS

URBAN

WATER

Analyzing current status and evolution trend in the last 20 years, the author would
like to propose following recommendations aiming at sustainable urban water
management in Vietnamese urban areas.
Establish a National Strategy and a National Target Program on urban water
management. River basin management approach should be realized. The
principles of integrated water resources management and a river basin approachshould be applied as a means of achieving coordination across sectors andreduction of the current sector fragmentation. An integrated approach to34

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implementation with components of water supply, sanitation and hygiene is likely
to produce more sustainable results and more benefits. There is a need to promoteand develop coordination mechanisms between water resource management andenvironmental protection agencies, water supply and sanitation companies andcommunity organizations at all stages of project planning and implementation,
within a river basin context.
The current commitment by central government to water and sanitation
improvement needs to be sustained.
Co-ordination of government-donor dialogue on sector financing at a high level
and among government agencies at central and local levels needs to be improved.
Besides, additional financing sources, especially for sanitation investment, also
clearly need to be mobilized. These may be government grants in the short tomedium term, but in the longer run may change to other instruments, such as
issuance of government bonds, the introduction of property taxes and theintroduction of earmarked increases of personal income taxes. Increase ofwastewater tariff is a key tool to achieve O&M cost recovery and system
sustainability.
Full recovery of investment and O&M costs should be assured for water supply
systems. For wastewater systems, management and O&M of the wastewatercollection and treatment systems will be funded mostly through wastewater tariffs
paid by households. Besides, financial support for poor households should bemaintained (Figure 6).

Figure 5. Water and wastewater tariffs in selected cities (data from year 2012)(Source: EAP Sanitation review, WB, 2013)
Policies to encourage Public-Private Partnerships (PPP) and Private Sector
Participation (PSP) are to be developed and implemented. It is critical thatinvestments from the private sector in combination with Government result in acomplete wastewater system incorporating connections, network and treatment
facilities, and not just the most profitable element. Policies such as favorable loan
and tax conditions are needed to encourage the private sector to invest in resource
recovery from wastewater and sludge treatment including the use of reclaimed
water and production of wastewater-driven electricity and heat for sale the grid.
Water management in Vietnamesecities: Present
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October
2013, Hanoi,
Vietnam
October
2013, Hanoi,
VietnamFigure 6. Recommended sources for funding in urban water and wastewater
systems
Sanitation planning on a citywide or river basin wide basis should be initiallyconducted prior to mobilization of investment and implementation. The sanitationplans should carefully consider the performance of low cost technology options
and delivery approaches to provide efficient and affordable solutions for the rangeof physical and socio-economic conditions present in a city or river basin. Safe
and efficient resource recovery should be targeted in sanitation planning. The
reuse of treated wastewater and sludge in agriculture would bring significant
benefits to the integrated sanitation system.
With 60-70% of the cost associated with implementation of a wastewater system
resulting from the cost of a sewerage collection system, it is important to consider
alternatives, such as decentralized wastewater scheme, which could effectively
reduce overall investment costs as well as reduce ongoing operation andmaintenance costs. Application of decentralized scheme is site specific, limited toless dense urban areas in which land would be available to site smaller,
decentralized WWTPs. The goal here is to localize the collection of sewerage,
minimizing the use of long conveyance pipelines and pumping stations, as well as
reducing the capacity requirements for WWTPs. Decentralized scheme may not
be appropriate for densely populated urban areas, in which locating of evensmaller WWTPs becomes challenging as well as extremely costly in terms of siteacquisition.
Centralized scheme will cost more in terms of infrastructure improvement,
particularly with respect to sewerage collection aspects. However, centralized
scheme may be unavoidable in densely populated urban areas, where land issimply unavailable and collection systems may be limited to interception of drainsat key locations.
A combination of the use of centralized scheme for dense core urban areas, anddecentralized scheme in the remaining parts, with reasonable set of effluent limits

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would be both a logical and cost effective approach for wastewater collection andtreatment for Vietnamese cities. Decisions on project phasing and selection ofprioritized areas of investment should be based on comprehensive analysis.
Most of the urban wastewater systems in Vietnam are still employing combined
sewerage systems for collecting and conveying wastewater. The reason for this isrelated to both cost, as CSS is less costly, and to the ease of implementation, as
CSS can be implemented with far fewer pipes creating less construction impact inresidential neighborhoods. Further, CSS generally utilizes the existing drainage
system as secondary sewers for collecting wastewater from household, making it
necessary only to intercept that flow by use of combined sewer overflow
structures (CSOs) and then transport that flow to a WWTP for treatment. To date,a formalized program for household connections is generally excluded from theimplementation of CSS, again making it more attractive to decision-makers due toapparent simplicity of execution. It is important to take into account that CSSbased wastewater will usually have a low organic content, which may mean thattreatment is not necessary or at least that only simple treatment processes are
required. Where treatment is required, presence of storm drainage andgroundwater infiltration and seasonal fluctuation of wastewater flows should beconsidered. Awareness raising activities for the customers and public associatedwith proper operation and maintenance of CSS to prevent inclusion of solid waste
and solids retention in network in dray season, and to prevent hydraulic overloadof system during rainy seasons are to be considered. For some cities, investment
in “Flood Storage” facilities allowing “holding” of peak storm water flows which
can then be discharged in a more controlled manner to the WWTP can beconsidered as an promising technical solution (WB, 2012).
Separate sewerage systems (SSS) are designed to collect and convey only
sewerage, with drainage and rainwater specifically excluded. Such a system canoffer very significant benefits to the end user, in that household septic tanks canbe eliminated and households can be connected directly to an enclosed piping
system, which is not impacted by either solid waste or rainfall. Neighborhoododors long associated with CSS, can be effectively eliminated with SSS. The
quality of the wastewater collected and transported to the WWTP is strictly
limited to household sewage and as such, is of high organic load concentration.
The amount of flow collected and pumped is less, allowing downstream WWTPs
to be designed with lesser capacities. In terms of investment cost, the SSS will be
more costly than CSS, as three systems of piping, primary trunk mains, secondary
sewers (located in streets) and tertiary sewers (located in sidewalks) will be
required. However, the investment in SSS results in the inherent advantages
mentioned earlier. The use of separate sewer systems should not be overlooked
for consideration during project formulation, as the benefits to the end user are
significant.
It is recommended to design SSS for all new urban development areas. Strict
urban management measures should take place in order to control construction
design, project implementation and system operation to avoid wrong connectionof drains and sewers. Household connections, construction of the sewerage
network and the downstream WWTP should take place at the same time. For that,

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October
2013, Hanoi,
Vietnam
October
2013, Hanoi,
Vietnamstaged development of WWTP components should reduce financial pressures
keeping high efficiency of the investments. For existing urban areas where
upgrading of CSS and collection of wastewater can’t be realized in a short periodof time, investment in the WWTP should be carried out in stages following
gradually expanding sewerage network and household connections. When
warranted, it is proposed to apply in the first stage the first unit of a combinationof unit processes. Advancing in stages simplifies the handling of the system andmaximizes budget utilization efficiency.
Summary of recommended wastewater collection and treatment schemes ispresented in Figure 7.
Present situation 1. On-site sanitation or Open defecation

Present situation 2. Septic tank (ST) + Combined Sewerage System (CSS)

Recommended Option 1a (ST + CSS + Centralized Wastewater Treatment Plant WWTP), 1b (ST + CSS +decentralized WWTP)

Recommended Option 2a (SSS + Centralized WWTP), 2b (SSS + decentralized WWTP)

Recommended Option 3a (ST + SSS + Centralized WWTP), 3b (ST + SSS + decentralized WWTP)38

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Figure 7. Summary of recommended wastewater collection and treatment schemes
In both CSS and SSS, flood management should be well taken based on river
basin management approach where appropriate “less impact development”
solutions should be considered. Storm water flow delay and attenuation using
natural and constructed systems are now widely used under the concept called“Sustainable urban drainage solutions – SUDS”. Examples of SUDS are given in
Figure 8. SUDS should be widely used in urban and transportation drainage in
Vietnam. Legal framework and system of design standards should be developed
accordingly. Harvesting and storage of storm water can also lead to other benefits
such as stored water can be used for fire protection, car and toilet flushing,gardening, air conditioning, etc.

(a)

(b)

Figure 8 (a, b). Examples of flood prevention solutions SUDS
Ensure balance between treatment facilities and collection systems in investment
programs. Each wastewater project phase should be developed on a holistic basiswith an appropriate investment balance among project components, including
wastewater and septage treatment facilities, household connections, drainage andwastewater collection. A household connection policy with either combined or
separate systems should be identified at each project stage and enforced byregulation. Engineered facilities should be designed together with ‘’soft
interventions’’ such as capacity building, management structures and financial
mechanisms.
Promote efficient institutional and regulatory arrangements at the local level.
Government should encourage local authorities to integrate physical infrastructuredevelopment with improving ongoing service delivery. This implies greater
efforts to improve public awareness, hygiene promotion and institutional
development both at the utility management and regulatory level.

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October
2013, Hanoi,
Vietnam
October
2013, Hanoi,
VietnamGreater emphasis needs to be placed on the selection of water and wastewater
treatment technology. Selection of the most appropriate treatment technology
involves technical evaluation of key criteria, namely: (a) land availability; (b) lifecycle costs, incorporating investment and O&M costs; and (c) suitability toachieve discharge requirements. By using appropriate technology treatment
processes, savings can be made both in investment and O&M cost.
The technical solutions, with an integrated treatment for the different waste
fractions, for example, septic tank sludge, sludge from future wastewater
treatment plants, as well as organic waste, should be encouraged. A central aim isa smooth and sustainable operation of the units especially concerning handling of
the above mentioned waste flows for public health and environmental protection.
The produced biogas caters for an energy self-sufficient operation of the plants.
The digested sludge (residue) is further treated and utilized for hygienically safe
fertilizer to improve the soil quality, because it contains rich nutrients and organic
fibers ideal for plants. In this way integrated solution of sanitation in urbanizedarea for sludge and organic waste treatment becomes feasible. Furthermore, when
farming energy crops in the peri-urban areas, farmers can earn benefit in the newscheme. Once sewage network is established in future in the area, the operation
scheme of the anaerobic digestion system is changed to accept sludge produced
from the wastewater treatment plants. Thus the existing infrastructure can becontinuously used without major additional modification, which saves significant
expenditure of the municipality (Figure 9).

Figure 9. Scheme of integrated waste management system
Engineered facilities should be designed together with ‘’soft interventions’’ suchas capacity building, institutional and financial arrangements. Besides, IEC
programs to promote behavior change should be implemented to increase publicawareness and appreciation of the benefits of water, hygiene practice, andenvironmental sanitation.

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REFERENCES
Le Duy Hung, Corning J, Nguyen Viet Anh, Tran Viet Nga (2013). Vietnam urban
wastewater review. The World Bank. 2013.
MOC – WB (2013). Vietnam urban water supply database. Report of Credit No. 4028VIE. By Invest Consult Group – Toconet Korea Co. Ltd. March 2013.
Nguyen Viet Anh, Nguyen Hong Sam, Dinh Dang Hai, Nguyen Phuoc Dan, Bui Xuan
Thanh (2011). Landscape Analysis and Business Model Assessment in Fecal Sludge
Management: Extraction and Transportation Models in Vietnam. Final Report. For Bill
& Melinda Gates Foundation. December 2011.
Nguyen Viet Anh, Nguyen Khac Hai (2012). Vietnam water supply and sanitation sector
assessment report. For MOH – WHO – UNICEF (in Vietnamese).
World Bank. East Asia Pacific urban sanitation flagship study. 2013.
World Bank. GFDRR report on Cities and Flooding. 2012.

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Sanriku Tsunami and reconstruction of cities

Hiroshi NAITO
Architect / Emeritus Professor, the University of Tokyo

ABSTRACTThe 2011 Tohoku Earthquake and Fukushima nuclear accident were the largest natural disasters
ever experienced in modern Japanese history. As an architect, I am involved in the reconstruction
and urban planning of the damaged cities in the Sanriku Region. There, the meaning andsignificance of Architecture, Urban Planning, Civil Engineering, and our social system surrounding
them are being questioned from their basis. This is because ideal disaster prevention andreconstruction of cities attributes to the relationship between the nation and the individual. There isno single answer there. Yet, we need to seriously think about this issue. We would like to share thisissue with people of Vietnam who are currently witnessing a rapid change in their urban structure.
Keywords: Sanriku Tsunami, Reconstruction of cities and urban planning43

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Sanriku Tsunami and reconstruction of cities

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Sanriku Tsunami and reconstruction of cities

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Sanriku Tsunami and reconstruction of cities

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Sanriku Tsunami and reconstruction of cities

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Oral Sessions

A study on the development of risk
assessment method for urban fire according
to fire spread phenomena of exterior andwood materials
Young Jin KWON1, Bong Chan KIM2, In Hyuk Goo3
1
Professor, Department of Fire & Disaster Protection, Hoseo University, Korea
Jungangman@naver.com
2
M.Eng., Department of Fire & Disaster Protection, Hoseo University, Korea
3
Doctoral course, Department of Fire & Disaster Protection, Hoseo University,Korea
ABSTRACTIn Korea, there is a need for the introduction and investigation of Korea urban
fire simulation that can assess the risk of fire by local unit with fire prevention
districts, fire protect area, and other similar areas vulnerable to fire as targets. In
this regard, this study examined the applicability of the urban fire simulation in
Korea and conducted wood fire-resistance and aluminum composite panel tests toimprove the simulation based on the review of the applicability. A regression
analysis of the final carbonization depth was carried out, and the difference ofvertical combustion expanded properties of non-combustible aluminum composite
panels was identified. In the future, the improvement of urban fire simulation isconsidered to be needed through modeling.
Keywords: Urban fire, simulation, aluminum composite panel, Douglas-fir
1. INTRODUCTION
With the rapid economic gross and progress of urban congestion, developmentof Korea has mainly focused on the convenience of living and efficiency of space.
As a result, the emergence of high-rise, large and in-depth structures has become
more common. However, many deteriorated structures of various structures anduses such as traditional markets, shacks, and traditional village, etc. are also
located, and they have characteristics which are vulnerable to disasters andcalamities, especially to fire. These areas and districts are specified as fire
prevention districts in the ‘National Land Planning and Utilization Act’ and fire
protect area in the ‘Fire Safety Law’. However, the fire prevention districts andfire protect area are designated by local governors, and there is no special
evaluation method on the designation of fire prevention districts and fire protect
area.
The fire prevention districts, fire protect area and similar areas vulnerable tofire have characteristics that lead to the rapid spread of a fire due to overcrowded
structures within a certain district, resulting in the collapse of buildings. For
instance, a fire that occurred in Insa-dong in February 2013 totally destroyed 23

53

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2013, 2013,
Hanoi,Hanoi,
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Vietnam

2013

2011

Figure 1 : Big Fire in Korea
stores as shown in Figure 1, and 13 buildings of a total of 33buildings were burnt
down by a fire that occurred in shacks located in Gaepo-dong, Gangnam-gu inJune 2011. In a related move, the Seoul City Government plans to equip ‘urban
fire simulation’ that can classify the grade of risks with areas vulnerable to fire astarget. However, there are few studies on the urban fire simulations other thaninternational joint research projects implemented by NIST, BRI (Japanese
Building Research Institute) and Hoseo University. In this regard, there is a needto introduce and study Korean urban fire simulation that can assess the risk of fireby local unit with fire prevention districts, fire alert districts and other similar
districts vulnerable to fire as primary target.
Accordingly, this study attempted to examine the applicability of urban fire
simulation improved by the international joint research of Hoseo University, BRI
and NIST in Korea. In addition, this study aims to obtain data used as a basis forthe improvement of the urban fire simulation by conducting aluminum composite
panel test and wood fire-resistance test to improve the simulation based on thereview of applicability.
2. REVIEW ON THE APPLICABILITY OF URBAN FIRE SIMULATION
2.1 Overview of the urban fire Simulation
The urban fire simulation was developed by the BRI, and Ministry of land,
Infrastructure and Transport for five years from 1998, and it was Improved
through and international joint research of Hoseo University, BRI and NIST in
2009. The basic scenario of the urban fire simulation is shown in Figure 2. In theurban fire simulation, a total of five structures can be set, and one kind can beselected among a total of 22 uses. In addition, input is possible with respect tovarious conditions such as damages from earthquake, and detailed data is required
for this.

Figure 2 : Basic scenario of urban fire simulation

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2.2 Analysis conditions of the urban fire simulation
For the review of the applicability of the urban fire simulation, two kind of casestudies were carried at based on fire cases, and a comparison between the firecases and analysis results was conducted.
2.2.1 Case study 1 –Shacks in Gaepo-dong, Gangnam-gu
In Gaepo-dong, Gangnam-gu, deteriorated shacks are concentrated, and 13
buildings were totally destroyed by a large fire that occurred in 2011. The
conditions set for a simulation analysis are shown in Table 1. Originally, woodand sandwich panels were used for most of buildings. However, since theapplication of sandwich panels is impossible, the buildings were set with wood.
Their use was determined to be a residence, and the total analysis times was set to
120 minutes. The fire building, wind speed and wind direction were set inaccordance with the same conditions at the time of the fire.
2.2.2 Case study 2 –Area crowded with restaurants in Insa-dong
In case of the area crowded with restaurants in Insa-dong, deteriorated woodenbuildings are concentrated, and 19 stores were burnt down by a large fire that
occurred in February 2013. The conditions set for a simulation analysis are shownin Table 1. 120 minutes were set as the total analysis time as in the case of shacks
in Gaepo-dong, Gangnam-gu, and the fire building, wind speed and winddirection were set in accordance with the same conditions at the time of the fire.
Table 1 : Detail setting conditions of simulation
Structure

Use

Opening

Time

Case 1

Wooden,Fireproof

Housing

General120minCase 2

Wooden,Fireproof

Sales
facility

General120minIgnition
Point
Actualignition
point
Actualignition
point

Wind
3.4m/sNorthwester
4m/s
Northwester

2.3 Analysis results of the simulation
2.3.1 Case study 1 –Shacks in Gaepo-dong, Gangnam-gu
The simulation results showed that the fire point and neighboring buildings
started to be burnt down in about 60 minutes, and the fire spread to more than
80% of the entire building in about 80 minutes. It can be identified that after 120
minutes, the fire spread to all wooden buildings except for fire-resistance building.
The results of the simulation identified over time are shown in Figure3.

A studyon the developmentof risk method
assessment
methodforaccording
urban firetoaccording
to fireA study on thedevelopmentof risk assessment
for urban
fire
fire spreadspreadphenomenaofexteriorandwoodmaterials
phenomena of exterior and wood materials

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2.3.2 Case study 2 –Area crowded with restaurants in Insa-dong
The simulation results found that the range of the fire spread to about 50m
radius in 60minutes, and the number of buildings which started to burnt down
rapidly increased 70 minutes later. In addition, it was identified that the fire
spread to more than 40% of the entire building in the area after 80 minutes, andmore than 50% of the buildings 100 minutes later. And finally, 10buildings turned
out to be totally destroyed. The results of the simulation identified over time areshown in Figure 4.

Figure 3 : Result of simulation(Case study 1)

Figure 4 : Result of simulation(Case study 2)

2.4 Comparison of actual and simulated fireAs for the Case Study 1, a comparison between the range of the damages
caused by the actual fire after 60 minutes and that of simulation after 60 minutes
is shown in Figure 5. In case of the actual fire, the range of the damages was
totally destroyed after 60 minutes. On the other hand, the range of the fire
expanded was similar, but only some of the buildings turned out to be burnt downin the simulation results.

Figure 5 : Comparability of fire spread
range

56

Figure 6 : Fire spread of exteriormaterial by opening

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Even in case of the Case Study 2, the range of the damages caused by the actual
fire after 60 minutes was found to be similar to that of the analysis on thesimulation, but only some part of the buildings were burnt down in the analysis
compared to the results from the actual fire. In addition, it turned out that a fire in
the outer wall itself does not occur in case an opening is not set as shown in
Figure 6.
2.5 Discussions
The results of performing case studies to review the applicability of urban fire
simulation found that it can be applicable to the range of fire spread in domestic
wooden buildings, but there is a limit to the estimation of the collapse resulting
from the total destruction by fire. In addition, it cannot simulate the actual fire incase the spread of fire to the adjacent buildings is caused by the outer wall. In thisregard, it is required to conduct experiments and analysis on the estimation on thecollapse of wooden buildings and the spread of fire caused by external materials.
3. FIRE-RESISTANCE TEST AND ANALYSIS FOR THE ESTIMATION
OF THE COLLAPSE OF WOODEN BUILDINGS
3.1 Experimental purposes and Methods
As a basic experiment for the estimation of collapse of wooden buildings, afire-resistance test was conducted using a horizontal furnace. For heating
conditions, heat was applied for 60 minutes based on the ISO 834 standard
heating curve. As a timber used as specimen, Douglas-fir, which has mainly used
for building structures, was used. In addition, the specimen was divided into a
total of five kinds according to the flame retardant treatment and moisture content
as shown in Table 2. And the final carbonization depth was measured by cutting
the specimen after the end of the experiment.
Table 2 : Condition of each specimen
Classification
NontreatedTreatedGeneral
Water impregnation
Flame retardant liquid
Oily flame retardant paintAqueous flame retardant paint

Moisturecontent
9.9 %25.3 %
18.1 %
9.6 %9.4 %WeightSize

27.9 kg
26.8 kg
26.2 kg
26.6 kg
26.5 kg

300×300×500(mm)

3.2 Experimental results
The results of cutting the specimen after the cooling process after the end of theexperiment are shown in the Table 3. In case of the general specimen, the depth ofcarbonization was measured at 3.8cm, and it was measured at 3.5cm, in case of
the water impregnation, 3.7cm in case of the flame retardant liquid, 4.0cm in caseA studyon the developmentof risk method
assessment
methodforaccording
urban firetoaccording
to fireA study on thedevelopmentof risk assessment
for urban
fire
fire spreadspreadphenomenaofexteriorandwoodmaterials
phenomena of exterior and wood materials

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October
2013, 2013,
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Vietnam0ctober
Vietnamof the oily flame retardant paint, and 3.8cm in case of the aqueous flame retardant
paint. Figure 7 shows the comparison between the final carbonization depth
measured and data obtained from the Kyoto University in Japan. As a result of theregression analysis, ‘y=28.31ln(x)-79.088’was deduced, and the coefficient ofdetermination (R2) turned out to be high (0.9246).
Table 3 : Charring depth of each specimen after cutting

Charring
depth

Flame
Water
Generalretardant
impregnation
liquid
3.8 cm

3.5 cm

3.7 cmOily flame
retardant
paint

Aqueous flame
retardant paint

4.0 cm

3.8 cmFigure 7 : Regression analysis of charring depth
3.3 Analysis methods
For the estimation of wood carbonization depth, an analysis was conductedusing a simple prediction equation of ‘Kosuke Kajiyama’. The analysis of woodcarbonization depth X can be carried out using the density ρ of the specimen andtemperature measured by equation 1.

X 

2 charL(T 2 T 1)(t  t0 )(1)

The carbonization occurrence temperature T1 was fixed at 288℃, the latent heatof pyrolysis L 4260000J/kg, and the thermal conductivity of coal λchar 0.18W/mk.
As for fire-side temperature T2 and wood density, values measured in theexperiment were used.

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3.4 Analysis results
As a result of conducting an analysis, the difference between the carbonization
depth measured in the experiment and values obtained by the analysis results
turned out to be large as shown in Table 4. Through the results of re-estimation of
the actual carbonization depth measured in the experiment by applying thecorrection value f tocharof equation 1, the actual carbonization depth wasLestimated on each specimen as shown in Figure 8.
Table 4 : The analysis results and correction value of each specimen

Analysis
Correction
value fFlame Oily flame
Water
Aqueous flame
Generalretardant retardant
impregnation
retardant paintliquidpaint
1.2 cm1.82 cm
1.84 cm
1.83 cm
1.83 cm
4.5

3.7

4

4.8

4.3

Figure 8 : Re-analysis for prediction equation
3.5 Discussions
The actual carbonization depth that occurs after the experiment is adjudged tohave no great relevance with the flame-retardant treatment. In addition, theanalysis results showed that it seems to be possible to estimate the carbonization
depth using the correction value f according to changes in time, but additional
experiments is required for securing reliability. In addition, since the correction
value f has a significant impact on the thermal conductivity of the carbonizedlayer in the analysis, more in-depth analysis on the thermal conductivity of the
carbonized layer according to the flame-retardant treatment will be needed.

A studyon the developmentof risk method
assessment
methodforaccording
urban firetoaccording
to fireA study on thedevelopmentof risk assessment
for urban
fire
fire spreadspreadphenomenaofexteriorandwoodmaterials
phenomena of exterior and wood materials

59October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnam4.

VERTICAL COMBUSTION EXPANSIONALUMINUM COMPOSITE PANELSEXPERIMENT

OF

4.1 Experimental purposes and Methods
To identify the fire expansion properties by conducting a vertical combustion
expansion experiment of aluminum composite panels, external materials with aconsistent increase in the frequency of use in Korea, an experiment was carriedout based on the ISO 13785-2 “reaction-to-fire tests for facades –Part 2: Largescale test”. Characteristics of the specimen are shown in Figure 9, and heat flux
and temperature was measured. The experiment was conducted using a propane
gas burner with gas flow rate of 0~120g/s for a total of 25 minutes, and it was
carried out with two conditions of general aluminum composite panels and semi
non-combustible aluminum composite panels. (Figure 10)

Figure 9 : Installation location of
Heat flux and thermocouple

Figure 10 : Installation of aluminumcomposite panel

4.2 Comparison properties of aluminum composite panels
The combustion of general aluminum composite and semi non-combustible
aluminum panels started in 2minutes and 3minutes respectively, and the flamesreached the top of the panels after 5 minutes. In case of the general aluminumcomposite panels, the combustion was rapidly expanded to the top of the opening,along with the side wall after about 8 minutes whereas, a slow process of
becoming inflammatory state was found at the part in which the flame did notreach directly in case of the semi non-combustible aluminum composite panels.
As for general aluminum composite panels, the experiment was terminated after 9
minutes since the flames soared up to 7m, whereas the experiment lasted for 25
minutes in case of the semi non-combustible aluminum composite panels.

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4.3 Comparison of the temperature and heat flux of aluminum composite
panelsFigure 11, 12 show a graph that compares the temperature with some of heat
flux measured in the experiments of the general aluminum composite panels(Experiment 1) and semi non-combustible aluminum composite panels(Experiment 2). The difference between the two experiments can be identified inabout 5 minutes, and the TC-7 of the aluminum composite panels was measured atabout 40℃ higher compared to that of the semi non-combustible aluminumcomposite panels. In case of the heat flux, the highest heat flux of the H/F2
showed a difference of about 20kW/m2, and a difference of about 3 minutes wasfound in case of the point of time when the highest heat flux is reached.

Figure 11 : Comparing the temperature of experiment 1 and 2

Figure 12 : Comparing the heat flux of experiment 1 and 2
A studyon the developmentof risk method
assessment
methodforaccording
urban firetoaccording
to fireA study on thedevelopmentof risk assessment
for urban
fire
fire spreadspreadphenomenaofexteriorandwoodmaterials
phenomena of exterior and wood materials

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Vietnam

4.4 Discussions
The experimental results of the general aluminum composite panels and semi
non-combustible aluminum composite panels found that the flames reached thepanels at the top after 5 minutes, which is attributed to the factors of the side wall,
not the actual combustion expansion. In case of the semi non-combustible
aluminum composite panels, it seems to be possible to delay the combustion
expansion at the part in which direct flames are not reached after 13 minutes.
However, since the combustion was expanded up to 4m at the corner, the risk of
combustion expansions to the upper part is considered to be still great.
5. CONCLUSIONS
From the results of experiments and analysis for the improvement of simulation
and review on the applicability of urban fire simulation, the following conclusions
were obtained.
1) The range of fire spread in wooden buildings was similar to that theactual fire, and different aspects were found in the collapse and total
destruction by fire. In addition, identified that the combustion of the outerwall itself cannot be considered in cased there are no openings.
2) As a result of conducting wood fire-resistance test, it was found that thedifference of the carbonization depth according to the flame-retardant
treatment does not occur in the actual carbonization depth. In addition, theregression analysis was conducted after comparing the final carbonization
depth and data of Japan, subsequently deducing ‘y=28.31ln(x)-79.088’. In
addition, the estimation of the carbonization depth was carried out using
the correction value f obtained from the results of the analysis using asimple prediction equation.
3) The results of the vertical combustion expansion experiment of thealuminum composite panels found that general aluminum panels were
measured about 400℃ higher at the TC-7, and about 20kW/m2 higher atthe H/F2, which indicates that the difference of the vertical combustion
expansion according to the internal core materials is great.
In the future, the improvement is required to apply the urban fire simulation to
Korea through the fire propagation modeling by the external materials between
adjacent buildings, and to conduct analytical research on the vertical combustion
expansion of aluminum composite panels, along with the establishment ofcollapse models through more in-depth experiments and analysis on the
carbonization depth and strength degradation of structural members.
REFERENCES
BongChan, Kim, 2012, A study on the fire spread phenomena of aluminium
composite panel and Douglas-fir for urban fire risk assessment, Master’s Thesis,
Hoseo University, Korea.

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Self-help approach in housing reconstruction
and beneficiaries’ satisfaction in Palestine
Adnan ENSHASSI1 and Mohammed ABU ZAITER2
1,2
Department of Civil Engineering, IUG, Palestine
aenshassi@gmail.com
ABSTRACT
Everyone has a right to adequate housing. Plans to reconstruct damaged ordemolished housing as a result of the conflict remain largely stagnant. Lack ofaccess to raw building materials, remains the major reason for the chronic
weakness of progress in reconstruction in Gaza. The main approach which has
been used in housing reconstruction process in Gaza strip after the war is OwnerDriven approach which is called "Self-help approach", where conditional
financial assistance is given, accompanied by regulations and technical support
aimed at ensuring that houses are built back better. More than 90% of the homes
have been reconstructed by this method. This paper aims to determine theefficiency of the self-help approach of housing reconstruction in Gaza
reconstruction process and to determine the satisfaction of the beneficiaries fromthis approach. The methodology that is used in this study was direct observations,interviews and questionnaire. It was found that there is significant efficacy of theself-help approach and there is a great satisfaction to the beneficiaries of thereconstruction projects in this way.
Keywords: disaster, housing, post-disaster reconstruction, self-help, Gaza Strip
1. INTRODUCTION
Gaza Strip is a coastal strip of land on the eastern shore of the Mediterranean Sea,bordered on the south by Egypt, on the west by the Mediterranean Sea, and on thenorth and east by Occupied Palestinian lands between 31 25 N, 34 20 E (CIA2012). The area of the Gaza Strip is 378 sq km (Encarta 2005). It has one of thehighest overall growth rates and population densities in the world. In 2007 PCPS
indicated that the population was 1,416,543 where the population density was
3,747 persons per sq km (PCPS 2009), and it is estimated to be 1,710,257 in July2012 (CIA 2012).
In December 27th 2008 war was launched in the Gaza Strip which was called“Casted Lead”. The war stopped on January 18th 2009. The estimated value of alldamage caused by Cast Lead war on Gaza Strip is about US$1.1 billion (Barakat
et al., 2009). The Palestinian Central Bureau of Statistics (PCBS) reports that
4100 housing buildings destroyed, 17000 houses damaged, 20 mosques, 25
education and health buildings and 1500 factories, shops and other commercial
facilities completely destroyed. Shelters will require the construction of about

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5000 homes for families who had lived in houses which were destroyed in andbefore the 2009 war (Al-Qeeq & El-Wazir 2010).
Post-disaster reconstruction, if not well planned and implemented, can create
further vulnerabilities in a disaster affected community. According to Schilderman(2004), whilst the number of hazard events does not appear to be increasing
greatly, their impact on people is increasing (Chang et al., 2010). Plans toreconstruct housing damaged or demolished as a result of the conflict remain
largely stagnant (Shelter Sector-Gaza, 2012). Lack of access to raw building
materials, remains the major reason for the chronic lack of progress inreconstruction in Gaza.
A number of strategies and options can be identified based upon previous attempts
at reconstruction in Gaza and also upon international best practices. Any project
should attempt to find social and physical appropriate planning and design
methods to help advancing the post-war reconstruction efforts in the Gaza Strip(Al-Qeeq & El-Wazir 2010). Five predominant approaches are adopted in thecontemporary reconstruction practice: Cash Approach, Owner-Driven,
Community-Driven, Agency-Driven Reconstruction in-Situ, and Agency-Driven
Reconstruction in Relocated Site (Chang et al., 2010; Barakat, 2003; Stephen etal., 2010). The main approach which has been used in reconstruction process in
Gaza strip after the war until now is Owner-Driven approach which is called"Self-help approach". In this approach conditional financial assistance is given,accompanied by regulations and technical support aimed at ensuring that houses isbuilt back better. More than 90% of the homes that had been reconstructed by thisway. This paper aims to determine the efficiency of the Self-help approach ofreconstruction in Gaza reconstruction process in addition to determine thesatisfaction of the beneficiaries from this approach.
2. LITERATURE REVIEWDisasters had great effects on the region and community that they occurred
physically, socially, economically and psychologically. The community
sometimes uses most of its capacity to overcome the situation and sustain their predisaster daily life. The most important problem revealed after the emergency
phase is especially to meet the shelter needs of the affected population (Arslan &Ünlü 2008).The International Federation of Red Cross and Red Crescent Societies
defined disaster as: a sudden overwhelming and unforeseen event. At thehousehold level, a disaster could result in a major illness, death, a substantial
economic or social misfortune (Johns 2008). At the community level, it could be aflood, a fire, a collapse of buildings in an earthquake, the destruction of
livelihoods, an epidemic or displacement through conflict (Hopkins 2008). Other
disaster definition is a widespread human and material or environmental loss
which exceeds the ability of the affected society to cope using its own resources(Coppola, 2007, p.25, cited in Mohapatra 2009).
Communities that have faced natural disasters, classifies disasters as Natural (e.g.,
earth-quakes, hurricanes, floods, wildlife fires etc.) or technological (e.g.,terrorism, nuclear power plant emergencies, hazardous materials etc.) (Hristidis,
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et al., 2010). Conflicts definitely are in need of complicated and interrelated
processes and arrangements to go through reconstruction processes, rehabilitation
and recovery as well (Barakat et al., 2009). Baradan (2006) explained that postdisaster housing reconstruction is a process of planning, defining strategies,
preparation of operation plans, implementations for reconstruction after disasters.
Unlike other relief items such as food aid or medicine, housing is a significant,long-term and non-consumable asset (Barakat 2003).
Post-disaster housing reconstruction can be undertaken through different
approaches, which vary principally in terms of a household’s degree of control
over the reconstruction process. Jha et al (2010) defined five reconstruction
approaches that may be pursued after a disaster:• Cash Approach: Unconditional financial assistance is given without
technical support.
• Owner-Driven Reconstruction (ODR): Conditional financial assistance isgiven, accompanied by regulations and technical support aimed atensuring that houses is built back better.
• Community-Driven Reconstruction: Financial and/or material assistance ischanneled through community organizations that are actively involved
in decision making and in managing reconstruction.
• Agency-Driven Reconstruction in-Situ: Refers to an approach in which agovernmental or nongovernmental agency hires a construction company
to replace damaged houses in their predisaster location.
• Agency-Driven Reconstruction in Relocated Site: refers to an approach inwhich a governmental or nongovernmental agency hires a construction
company to build new houses in a new site.
Barakat (2003) indicated that the Post-disaster housing rebuilding priorities
require special attention to be paid to the implications of resource availability forreconstruction performance and to underlying resourcing bottlenecks in thereconstruction process. Four predominant resourcing approaches are adopted in
the contemporary reconstruction practice: government driven, donor driven,market driven, and owner driven (Chang et al., 2010). The choice of the bestreconstruction approach to be employed is context-specific and should take into
consideration (1) reconstruction costs; (2) improvement in housing andcommunity safety; (3) restoration of livelihoods; (4) political milieu; (5) culturalcontext; and (6) people’s own goals for well-being, empowerment, and capacity(Jhans et al., 2008). It is very important to make deep consultation with thecommunity and evaluation of requirements and capacities is critical before
deciding on any reconstruction approach (Chang et al., 2010).
While people affected by a disaster are the first to engage with the emergency,
they are often perceived as victims of the disaster rather than as the critical driving
force behind reconstruction (Jhans et al., 2008). Sadiqi, et al., (2011) indicatedthat local communities and the survivors of a disaster play a crucial role in postdisaster reconstruction and their participation ultimately determines projectsuccess. Effective community participation in reconstruction process should beinstigated. Empowering communities to participate in the reconstruction process
can be highly inspiring to the recipient stakeholders of resulting projects and________________________________________________________________________
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provides an opportunity for members to contribute their knowledge and skills.
This is made possible when affected communities are effectively involved in all
stages of the post-disaster reconstruction (Sadiqi, et al., 2011). Post-disaster
practices must embrace greater involvement of the affected communities and local
institutions specially households of destroyed home in the process ofreconstruction (Allen 2006). In an ODR approach, people who lost their shelter
are given some combination of cash, vouchers, and in-kind and technicalassistance to repair or rebuild their houses (Jha et al., 2010). They may undertakethe construction or repair work by themselves, by employing family labor, byemploying a local contractor or local laborers, or by using some combination ofthese options. ODR is similar to the “Self-Help approach” (Barakat 2003).
In general, the more intensive the community engagement in reconstruction
planning, house design, beneficiary selection and construction management, thegreater is the beneficiaries sense of ownership of and satisfaction with their new
homes, and the higher are occupancy rates (Westover 2004). ODR requires goodoversight and governance, that is, a government capable of establishing andenforcing standards, and some agency (governmental or nongovernmental) toensure the quality of construction (Jha et al., 2010; Barakat 2003). A self-help
approach encourages the active participation of the disaster-affected community;
it may be a useful way of restoring a sense of pride and well-being in people whohave been through a trauma (Petrini et al., 2012; Barakat 2003).
Success lies in establishing a support system for homeowners appropriate to the
local context, Jha et al., (2010) indicated that to make self-help approach more
effective and efficient, some conditions should be proceeded which may include:• Training of trades people and homeowners.
• Technical assistance and construction supervision and inspection.
• Updating and enforcement of building codes and construction guidelines.
• Mechanisms to regulate prices and facilitate access to building materials.
• A system for providing financial assistance in installments as construction
progresses.
An owner-driven approach entails some risks and drawbacks These risks can beovercome through the introduction of building codes and adequate technicalassistance (Jha et al., 2010). In self-help approach beneficiaries were brought into
assessing the hazards and identifying the design features needed as well as werebrought into the construction process. The participatory housing design
methodology sought beneficiary knowledge through: structured and semi
structured interviews; modified participatory and vulnerability mapping andparticipatory rural appraisal; field observations; focus group discussions and theinclusion of building regulations, donor technical specifications and beneficiary
specifications as well as hazard mapping of the individual sites (Ibrahim 2010).
3. METHODOLOGY
Reconstruction destroyed housing program funded by the grant of the Gulf
Cooperation Council for the reconstruction of Gaza in cooperation with theIslamic Development Bank, where reconstruction process depended on Self-help
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approach (Owner-Driven Reconstruction- ODR) was used as a case study. All therecords of meetings of the Steering Committee for IDB reconstruction programHousing Allocation, and final reports of these projects were studied and analyzed.
Interviews with members of the Steering Committee and number of interviews
were conducted with beneficiaries from these projects.
A questionnaire survey was adopted to determine the extent of satisfaction of thetarget group (beneficiaries from reconstruction project using Self-help approach).
The questionnaires were randomly distributed to 40 beneficiaries of the projects,
33 questionnaires were received.
The questionnaire was divided into two parts:
Section I: This section contains a series of questions related to personal features ofindividuals of the sample.
Section II: Level of satisfaction and their relationship with some variables which
consists of two parts.
The first part: The level of satisfaction in general about the process ofreconstruction-based self-help approach.
The second part: The level of satisfaction with the mechanism of reconstruction of
the beneficiary's house in particular.
Validity and reliability of the questionnaire had been confirmed.
Structure Validity: All the correlation coefficients in all areas of statisticallysignificant questionnaire when it is all scopes of the questionnaire ratified statusmeasured at the level of significance α = 0.05.
The value of Cronbach's alpha coefficient was high for each scope, ranging from(0.657-0.768). As well as the value of the coefficient alpha for all the paragraphsof the resolution was (0.797). This means that the reliability coefficient is high.
4. RESULTS and DISCUSSION
4.1 IDB housing reconstruction program description
The Islamic Development Bank (IDB) is the coordinator for the Program of the
Gulf Cooperation Council for the Reconstruction of Gaza, where thereconstruction process depended on Self-help approach (Owner-Driven
Reconstruction). A Conditional financial assistance is given to the beneficiaries
through payments equal to the reconstruction cost (260$-300$/sq meter),accompanied by regulations and technical support aimed at ensuring that houses
are built back better. The donor forms a steering committee to manage the processof reconstruction, with the following tasks:• Developing standards to beneficiaries.
• Directing the projects implementation.
• Solving problems and obstacles during the implementation.
• Monitoring the reconstruction process.
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Beneficiaries have built houses with area ranging from (90-180 square meters).
The committee policies have given the beneficiaries the flexibility to increase
their home's area and improve its quality from their own recourses provided thatall specifications and reconstruction conditions must be met. Partners andinstitutions overseeing the implementation of projects provide technical support
and guidance to the beneficiaries to complete the reconstruction process within
the planned budget and duration as well as a high quality. Before any financial
payment is paid to the beneficiary they have provided the following documents tosupervisor: (Drawings which is approved from the Municipal and Engineers
Association, time schedule and the implementation mechanism for reconstruction
process, providing a legal insurance for using the financial assistance just forreconstruction purpose.
The payments are paid in a line with the progress report and according to therecommendations of supervisors. The final installment is paid when thebeneficiary complete the reconstruction of their houses.
Table 1 shows the IDB housing reconstruction program components.
Table 1: IDB housing reconstruction program components
Fund
StatusNumber of housing units
allocation
Housing
Mercy
UNDP UN
Executing Agency
council
Completed
first
50
51
0
0

total

Budget$M

101

3,640,000

Completedsecond

39

37

46

0

122

5,432,000

In progress

third

71

71

0

260

402

13,227,700

In progress forth

150

230

0

220

600

29,437,700

In progress fifth

100

100

0

125

325

10,520,000

Total

410

489

46

605

1550

62,257,400

The average grant foreach housing unit

Totally reconstruction

40,000$Rehabilitation

8,860$

4.2 Advantages which is found in this approach (self-help approach)1- Households have taken an active role in rebuilding, which speeds recovery
from disaster psychological and social dependencies.
2- Assistance can be adjusted to the needs of the household related to income,family size, livelihoods, and socio-cultural requirements.
3- Overcoming political problems, which prevent the NGO's to use materials
that are entered by the tunnels.
4- Tends to involve local building industry, thereby contributing torestoration of local economy and livelihoods.
5- Allows people to “top up” housing assistance with their own savings andbuild a house reflecting their specific needs and aspirations.
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6- less subjected to disruptions caused by unstable political situation (forexample, blockade, closure of the crossings)
7- The beneficiaries are highly motivated and more belonging to their houses
in addition to the increasing spirit of cooperation in the community.
4.3 Disadvantages which is found in this approach
1- Beneficiaries' weakness in the management of reconstruction process
specially the financial management.
2- Instability of material prices in the market was the major risk faces thebeneficiaries
3- Beneficiaries had to bear some additional financial burdens as a result ofextensions of the home in excess of the grant.
4- It was more difficult with poor beneficiaries who have not experience inconstruction.
5- Difficulty to contract with technical construction worker for each home,causing price rises in many cases.
4.4 Beneficiaries’ satisfaction in self-help approach
Figure 1 illustrates the level of satisfaction in general about the process ofreconstruction-based self-help approach.

Figure 1: Satisfaction about the process of reconstruction-based self-help
approach
The results indicated that there is a high level of satisfaction in general about theprocess of reconstruction-based self-help approach.
Table 2 shows the level of satisfaction with the mechanism of reconstruction of
the beneficiary's house in particular.
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Table 2: Beneficiaries satisfaction with the mechanism of reconstruction process
Satisfaction
factors

MostlyMostlyDegree ofSatisfied Unsatisfied
satisfieddissatisfied satisfaction

Comfort ofreconstructed
home

46%

46%

6%

3%

83%

Home is hygienic

67%

24%

6%

3%

89%

24%

33%

36%

6%

69%

55%

27%

12%

6%

83%

70%

21%

6%

3%

89%

70%

21%

9%

0%

90%

70%

27%

3%

0%

92%

70%

24%

6%

0%

91%

67%

27%

6%

0%

90%

42%

49%

9%

0%

83%

52%

39%

9%

0%

86%

76%

24%

0%

0%

94%

Home isSafety/security ingeneralGeneral level ofhappiness/wellbeing
Beneficiaries
satisfaction withthe reconstructedhome
Beneficiaries
satisfaction withthe area ofreconstructedhome
Beneficiaries
satisfaction withthe distribution ofrooms andservices
Beneficiaries
satisfaction with
Electrical works
at homeBeneficiaries
satisfaction with
Home ventilation
Beneficiaries
satisfaction with
Speed ofexecution
Beneficiaries
satisfaction with
Speed the flow of
payments
Beneficiaries
satisfaction with
Dealing with the

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supervisory
Beneficiaries
satisfaction withTechnical
supervision of thesupervising party

76%

24%

0%

0%

94%

The result in the above table indicates that there is a high level of satisfaction withthe mechanism of reconstruction of the beneficiary's house in particular.
By analyzing the results of the questioner it can be indicated that:









There is a clear relationship between the method of reconstruction andsatisfaction of target group, since most of the beneficiaries expressed theirgreat satisfaction of this ways of reconstruction (Self-help approach).
The study showed that there is a clear relationship between the level ofsatisfaction and area of houses which were reconstructed. Homeowners
with small home area less satisfied than others.
The result also indicated that beneficiaries are satisfied with the
distribution of rooms and services and building conditions as a whole,because they are the main responsible for drawings and implementation of
construction process.
Most of the beneficiaries satisfied with the method of supervision appliedby the donor.
Most of the beneficiaries satisfied with the value of financial assistanceand the way the flow of payments, although some of them had to pay somemoney to complete the reconstructed home, in order to cover the increasein the area or the improvement in the specifications of the house.

Finally, the results indicated that there is clear consent of the beneficiaries to theself-help approach as an effective and efficient approach to reconstruct theirhomes.
5. CONCLUSION and RECOMMENDATION
The aim of this paper was to determine the efficacy of the self-help approach ofreconstruction in Gaza housing reconstruction process, in addition to determine
the satisfaction of the beneficiaries for this approach. It was found that there issignificant efficacy of the self-help approach, and that the beneficiaries are
satisfied with this approach.
Communities and households must have a strong voice in determining the postdisaster reconstruction approaches and a central role in the reconstruction process.

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Good planning principles and environmental practices should be incorporated,
whatever the reconstructions approach.
There should be a plan and a clear strategy for the reconstruction of Gaza in the
housing sector. Database of the war damages comparative studied and research
results of reconstruction projects should be prepared. Training programs inreconstruction approaches should be organized for policy-makers andpractitioners to exchange experiences from recent recovery operations.
REFERENCES
Allen, K. M., 2006. “Community-Based Disaster Preparedness and Climate
Adaptation: Local Capacity Building in the Philippines”. Disasters, Volume 30(1), pages 81-101.
Al-Qeeq, F. & El-Wazir, M., 2010. “Sustainable Housing Strategies in Post-war,
Reconstruction of the Gaza Strip”. International Congress: Rehabilitation andSustainability. The Future is possible”, Col·legi d Aparelladors & Tècnics i
Enginyers d’Edificació de Barcelona, 4th, October 2010, Barcelona.
Arsalan, H. & Unlu, A., 2008. “The Role of NGO’s in the Context of Post
Disaster Housing in Turkey”. 4th International i-REC Conference, “Building
Resilience: Achieving Effective Post Disaster Reconstruction”, 30 April-2 May
2008, Christchurch.
Baradan, B., 2006. “The Role of Information and Communication Technologies in
The Process of Post-Disaster Housing Reconstruction”. 1st International CIB
Endorsed METU Postgraduate Conference Built Environment & Information
Technologies, Ankara, pages 73-84.
Barakat, S., 2003. “Housing Reconstruction after Conflict and Disaster,”.
Humanitarian Practice Network at ODI, UK.
Barakat, S., Zyck, S. & Hunt, J. E., 2009. “The reconstruction of Gaza: A
Guidance Note for Palestinian and International Stakeholders”. Regional Human
Security Centre, Post- War Reconstruction & development Unit (PRDU).
Central Intelligence Agency, 2012. https://www.cia.gov/library/publications/theworld-factbook/geos/gz.html, Last Accessed date: April 15, 2012.
Chang Y., Wilkinson S., Potangaroa R., & Seville E., 2010. “Resourcing
challenges for post-disaster housing reconstruction: a comparative analysis”.
Building Research & Information, Volume 38(3), Pages 247–264.
Hristidis V., Chen S., Tao Li, Luis S. & Yi D., 2010. “Survey of DataManagement and Analysis in Disaster Situations”. The Journal of Systems andSoftware, Volume 83, pp. 1701–1714.
Ibrahim, M., 2010. “Post-Disaster Housing Reconstruction in a Conflict Affected
District, Batticaloa, Sri Lanka”. Strengthening Climate Resilience Discussion
Paper 6, Institute of Development Studies at the University of Sussex Brighton
BN1 9RE, UK. www.csdrm.org, Last Accessed date: April 15, 2012.
IDB, Fourth Quarter Report, 2012. “Grant of the Gulf Cooperation Council for
The Reconstruction of Gaza in Cooperation with the Islamic Development Bank –Jeddah”. April 2012, Gaza, not puplished.

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Jha, A., B. Jennifer Duyne, P. Daniel & Stephen, S., 2010. “Safer Homes,
Stronger Communities: a Handbook for Reconstructing after Natural Disasters”.
Washington, DC, World Bank.
Johns, H., International Federation of Red Cross & Red Crescent Societies Public
Health, 2008. “Guide for Emergencies“. A textbook, 2008, 2nd Edition,
Switzerland.
Mohapatra, R., 2009. “Community Based Planning in Post-Disaster
Reconstruction: A Case Study of Tsunami Affected Fishing Communities in Tamil
Nadu Coast of India”. A thesis presented to the University of Waterloo in
fulfillment of the thesis requirement for the degree of Doctor of Philosophy inPlanning, Waterloo, Ontario, Canada, 2009.
Palestinian Central Bureau of Statistics, 2009.“Main Indicators by Locality Type”.
http://www.pcbs.gov.ps/DesktopDefault.aspx?tabID=4151&lang=en,
Last
Accessed date: April 15, 2012.
Petrini, F., Vannucchi, S., Miraglia A., & Meringol, P., 2012. “Self-Help Groups
in a City of Tuscany: Reconstruction of the Second Generation Model of Work forProfessionals and Services”. Global Journal of Community Psychology Practice,
Volume 2(3), Pages 1-12.
Sadiqi , Z. Coffey, V. & Trigunarsyah, B., 2011. “Post-Disaster Housing
Reconstruction: Challenges for Community Participation”. In Proceedings of theInternational Conference on Building Resilience: Interdisciplinary Approaches toDisaster Risk Reduction and the Development of Sustainable Communities,
Heritance Kandalama, Sri Lanka. http://eprints.qut.edu.au/42177/, Last Accessed
date: April 15, 2012.
Schilderman, T., 2004. “Adapting Traditional Shelter for Disaster Mitigation andReconstruction: Experiences with Community- Based Approaches”. Building
Research & Information, Volume 32(5), Pages 414–426.
Shelter Sector Gaza, 2012. “Shelter Advocacy Fact Sheet 4”. Unified Shelter
Sector Database (USSD), http://www.sheltergaza.org, Last Accessed date: April
15, 2012.
Snider, H. & Takeda, N., 2008. “Design for All: Implications for Bank
Operations”.
Westover, N., 2004. “Lessons from A Post-Disaster Reconstruction Experiences”.
CIDA in consultation with its reconstruction partners in Indonesia following the
Asian tsunami of December 2004 .http://www.cowater.com/uploads/English.pdf, ,Last Accessed date: April 15, 2012.

________________________________________________________________________
Self-help approachin approachhousing reconstruction
and beneficiaries’satisfaction satisfactionin Palestinein Palestine
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Roles of self-help and mutual and local
government aid
in community-based disaster mitigation
Midori YAMAGUCHI1, Chiaki TAKEKUMA2 and Yoko TOWATARI3
1
Project Lecturer, RN, MPH, Kumamoto Health Science University, Japan
yamaguchi.mi@kumamoto-hsu.ac.jp
2
Professor, BSN, MW, PHN, Ph.D., Kumamoto Health Science University, Japan
3
Lecturer, RN, MW, PHN, MS (Sociology),
Kumamoto Health Science University, Japan
ABSTRACTDisaster mitigation means minimizing the damage occurring when a disasterstrikes. Whereas “disaster prevention” implies protection against damage,“disaster mitigation” involves the active reduction or control of damage,assuming that it is going to occur. There are two aspects to community-based
disaster mitigation. One is the “hardware” aspect, which includes such items as
the maintenance and development of social infrastructure. The other is the“software” aspect, which consists of human behaviors directed against disaster.
Currently, self-help and mutual and local government aid – for example throughcooperative activities – are essential because the human "software" input isessential to managing the social problems that accompany disaster mitigation
efforts. Now, in Japan, the numbers of people who need support in time of disasterare increasing because of the “super aging” nature of our society. There is
therefore an even greater stronger need for cooperative activities so that we canstrengthen the self-help and mutual and local government aid. This reportclarifies the roles of these three kinds of aid in community-based disastermitigation by introducing an example of disaster planning in Fukuoka Prefecture.
Keywords: disaster mitigation, mutual and local government aid, self-help
1. INTRODUCTION
Japan has suffered many disasters, including not only the aftermath of the 2011
Great East Japan Earthquake and Tsunami, but also yearly typhoons, floods, andsevere snowstorms. Japan’s environmental conditions make the country
susceptible to natural disasters, and social factors such as the type of living
environment, population density, and type of land use tend to enhance disasterdamage. Therefore, emergency response to disaster has become a major concern,and many sectors in this country are now collaborating in disaster management.
Community-based disaster mitigation is an essential part of disastermanagement. Disaster mitigation means minimizing or controlling the damage75

October
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Vietnam
October
2013, Hanoi,
Vietnamthat occurs when a disaster strikes. Disasters can destroy communities, andempowering leaders and the public with knowledge of available resources throughthe planning and development of disaster responses can strengthen a community’s
resilience.
Self-help and mutual and local government aid play a role in strengthening
community resilience. Today, the numbers of people in Japan who need support intimes of disaster are increasing because of the “super aging” nature of our society.
Therefore, there is an even greater need for cooperation to strengthen the
mitigative effects of self-help and mutual and local government aid.
This report clarifies the roles of these three kinds of aid in community-based
disaster mitigation by introducing an example of disaster planning in themunicipality of Miyama in Fukuoka Prefecture.
2. SELF-HELP AND MUTUAL AND LOCAL GOVERNMENT AID
Self-help and mutual and local governmental aid express the division of roles of
the individual, the community, and the administration. Under this principle ofsubsidiarity, the small units (individuals and the community) take the initiativeand make decisions, and the government provides subsidies. These cooperative
activities are essential, because human behavior, which can be seen as the“software” input in disaster mitigation, is essential to manage social problems in
the face of disaster.
In the Great Hanshin-Awaji Earthquake in 1995, about 80% of the people under
the rubble were rescued by families or neighboring residents (Kawada, 1997).
One report showed that the rate of self-rescue or rescue by family or neighbors
exceeded 90% in certain area. Despite the serious damage, the safety of allresidents was checked on the day of the earthquake by neighbors or the firebrigade. These examples show that self-help and mutual aid play a big role insaving lives in times of disaster. Moreover, in the Mano district in themunicipality of Kobe, residents used bucket relays to put out post-earthquake fires,
thus relying on self-help and the mutual aid of the local community (Araki, 2013).
Enhancing the capability of local communities is thus essential for disastermanagement and recovery. Such examples as those mentioned above show us thatdaily social connections within neighborhoods and communities are important.
Moreover, communities need to develop partnerships with local government.
Figure 1 shows the relationships among self-help and mutual and local
government aid in community-based disaster mitigation.

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Figure 1: Relationships among self-help and mutual andlocal government aid in community-based disaster mitigation

3. ASSESSING AND SUPPORTING VULNERABILITY
Previously, those who are vulnerable at the time of a disaster were referred to by
the acronym “CWAP”: Children, Women, Aged people, and the Poor or Patients.
In the current Japanese Government’s guidelines on disaster vulnerability, thevulnerable are now referred to as those who need support to collect the
information they need and evacuate to a safe place in time of disaster. These
people include the elderly, the disabled, non-Japanese speakers, infants, children,and pregnant women. Because of the aging of Japan’s population and a shift from
hospital to home-based care, the vulnerability of our population is increasing. We
have learned from previous disasters, including the 1995 Great Hanshin-Awaji
Earthquake and the 2011 Great East Japan Earthquake and Tsunami, that the
proportion of the elderly who are harmed in such disasters is high. Therefore, it isvital that we assess the vulnerable, support their evacuation, and prevent
secondary harm to them.

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4. PLAN FOR SUPPORTING THE VULNERABLE IN TIMES OFDISASTER IN MIYAMA MUNICIPALITY, FUKUOKA PREFECTURE
4.1 Aim and persons covered
A plan for supporting the vulnerable in times of disaster was devised as part ofMiyama municipality’s disaster prevention plan (March, 2011). This plan aims toprecisely assess the vulnerable and to support their safe evacuation when adisaster occurs. To do this, self-help among the vulnerable and mutual aid by thecommunity are fundamental, and social connections need to be strengthened.
More municipality plans to strengthen connections with other organizations suchas community leaders and volunteers. Information on the vulnerable is enteredinto a register and then shared by stakeholders such as community leaders,volunteers, and the leaders of various groups.
In the Plan, the following people are considered to be vulnerable:
a. Those aged over 65 years and living in households by themselvesb. Those certified as requiring long-term carec. The disabledd. Those who have mental disorders
The classification therefore does not apply to people who are receiving support
from families, those who are hospitalized, those living in care houses, or those
who can evacuate themselves.

4.2 Registration on the Vulnerable list
Those who are prepared to be registered on the list need to fill in private andpersonal information such as demographic data, disease history, and contact
persons. In addition, they must agree to give this information to community orgroup leaders. The information that is submitted is registered on the Vulnerable
list so that individual support plans, with mapping and refuge information, can becompiled. After the registration is complete, a “Information card” for urgent
communication is distributed (Figure 2). The registration card, together with theinformation held by local government and community leaders, can thus be used togive precise information to emergency services. Figure 3 illustrates the systemused to support the vulnerable.

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Figure 2: “ Information Card ” on the refrigerator
advice to put on a health insurance ID card, a consultation ID card, drug
information and own photograph, etc.

Modified due to Miyama m. information
Figure3: Plan for supporting the vulnerable in times of disasterin Miyama municipality

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5. FLOODS AND LANDSIDES IN NORTHERN KYUSHU IN 2012: THE
EXPERIENCE OF MIYAMA MUNICIPALITY
Floods and landslides caused by torrential rain “never before experienced”
occurred in 2012 in the prefectures of Fukuoka, Kumamoto, and Oita in northern
Kyushu (Fig. 4). Thirty people were killed and 27 were injured.
The municipality of Miyama is located in the southern part of Fukuoka
Prefecture. Its population is about 40,000, of which more than 31% of which areover the age of 65. Agriculture is a key industry. The Yabe River flows throughthe northern part of the municipality. In 1953, floods affected this area and 29
people were killed in the watershed. In the 2012 floods, 2 people were injured andmany houses and farms suffered huge amounts of damage. The disaster
experience revealed that the main problems were temporary refuge,communication, and support of the vulnerable.

Figure: 4 Map of the Kyushu prefectures affected by floods and landslides
in 2012

6. EVACUATION TRAINING BY A VOLUNTARY DISASTER
PREVENTION GROUP IN THE HONGO DISTRICT OF MIYAMAMUNICIPALITY
After disastrously heavy rain was experienced in 2012 a local volunteer disasterprevention group in the Hongo district of Miyama municipality performed
evacuation training. After refuge information is broadcast, a refuge support person
goes to the houses of vulnerable people and guides them to a temporary refuge.
When they leave the house they hang a towel on the fence or door post as amarker for the firefighting team (Figure 6). The firefighting team then checks allof the houses to ensure that the occupants are safe. The volunteers say that thetraining help them to prepare for disaster: they learn to remain calm and are thus

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better able to act. Training participants who live by themselves say that they feel
uneasy and anxious about evacuating in time of disaster and that they feel a needfor daily communication.

Figure 5: Evacuation by supporting volunteers

Figure 6: Hanging a towel on the fence or door post as a marker for the occupants
are already evacuated

7. DISCUSSION
The Hongo District is located in the sandbank of the river and the area is at highrisk of the flood. Resident awareness of disaster was high. The head of the district
took the initiative to organize the voluntary disaster prevention group and perform
evacuation the training with the cooperation of local government. Residents in theat-risk areas are now aware that they can protect their community by themselves.
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This case shows how mutual aid can be reinforced in an aging society. Voluntarydisaster prevention groups are especially needed in areas where the disaster risk ishigh. The organization rate increases after disasters; in 2012 it reached 70%
according to research on the status of voluntary disaster prevention groups insouthern Fukuoka Prefecture, and it is expected that this rate will increase further
with time. However, the organization rate in 5 of 12 cities is less than 50% in
southern Fukuoka, so there are substantial differences in organization rates amongareas(Tanaka, 2013). A lack of people among the aged who are able to lead groups
is a problem. Nevertheless, high levels of awareness and recognition amongresidents help to promote community-based volunteer activity. It is particularly
important to promote the organization of volunteer groups in areas considered to
be at high risk of disaster.
Support for the vulnerable is essential and beneficial. Even though such a system
has been set up in the Hongo district of Miyama municipality, there have been
problems with its proposal in other areas, as some people are hesitant to registerbecause of the need to reveal personal information.
8. CONCLUSION
Many disasters have occurred in our country, and disasters that are unexpected orthat we have never experienced before affect us every year. Security and safety
are basic human needs, and disaster preparation is indispensable. In disaster
responses we must cater to every situation and provide response measures
strategically. In community-based mitigation, the organization and continuation ofvolunteer disaster prevention groups are important activities. We need a systemthat is based on self-help and mutual aid among local residents, with appropriate
support from local government.
REFERENCES
Araki, C., 2013 Earthquake and Disaster Response in the Japanese Community: A
Strengths and Community Perspective. Journal of Social Work in Disability &Rehabilitation., 12:1-2, 39-47.
Fire and Disaster Management Agency in Japan., 2011 Jisyubousaisosikinotebiki(Guidelinesforvolunteer
disasterprevention
groups),http://www.fdma.go.jp/html/life/bousai/bousai_2304-all.pdf
Kawada, Y., 1997 Prediction of Loss of Human Lives Due to Catastrophic
Earthquake Disaster. Journal of Japan Society for Natural Disaster Science,
Vol.16, N.1, 3-14.
Kawada, Y., 2012 Korekarano bousai,gennsaiga wakaruhonn (Disaster
Prevention and Disaster Mitigation in the Future), Iwanami Junior Paperbacks
Tanaka, N., 2013, July 14. Preparedness for Disaster, Differences among areas,
Nishinihonn shinnbunn, p1
Miyama municipality., 2011 Master Plan: Plan of supporting the vulnerable at thetime of disaster.

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Sustainable safety and security
in private rental properties for students
in Hanoi: the tenants’ perspective
Thi Mai NGUYEN 1, Anh Quan PHUNG 2 and The Quan NGUYEN 3
1
Undergraduate student in 54KT6 class,2
Lecturer, Faculty of Construction Economics and Management,
3
PhD, Vice Dean, Faculty of Construction Economics and Management,
1, 2, 3National University of Civil Engineering, Hanoi, Vietnam
nguyenquan.nuce@gmail.com
ABSTRACT
Sustainable urbanization requires that all forms of development and associatedpolicies be judged on the basis of three criteria: economy, ecology and equity.
Therefore, together with developing economic infrastructure supporting economic
activities, cities need to provide social infrastructure assets for accommodatingsocial services to secure a better living quality for urban inhabitants. This paper
looks into the practices of safety and security in student rentals in Hanoi, using
data collected from a survey with participants as students from universities andcolleges in the city. The paper investigates the issues in student rentals in order tofind out significant influential factors affecting safety and security in this rental
market under the tenants’ perspective as well as important criteria to theiraccommodation choice. According to the survey results, the survey participants
have experienced thirteen factors causing their safety and security risks in rental
accommodation, whose average impact levels are recorded. Among the factors,
the most significant influential factors include “security quality of rental
properties” and “security issues in neighborhood areas” which bring the highest
risks for tenants as students. Among seventeen criteria for rental accommodation
choice and their level of contribution to the choice which are presented andanalyzed, those relates to safety/security risks belong to the most important group.
The influential factors to safety/security risks then are analyzed to measure theirlevel of importance to accommodation choice. The results imply that tenants,
landlords and the local government authorities need to pay attentions to thosefactors in order to contribute to the sustainable development of this rental market
as well as this type of urban citizens.
Keywords: accommodation safety and security, safety/security risks, student
rentals, accommodation choice criteria, living quality.
1. INTRODUCTION
The number of students studying in universities, colleges and vocational schools
account for a significant proportion of the population of Hanoi. In 2009, there
were about 800.000 students studying in Hanoi, accounting for more than 46% the83October
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total number of students all over the country, which was 1.719.499 students in2009 (Phan Duong, 2009). Since 2009, due to the expansion of existing
universities and the entrance of new universities to the market, there are about one
million students currently living and studying in Hanoi and the number is still
increasing. Consequently, the student population accounts for about one-seventh
the total population of Hanoi. This type of citizen also needs a lot of infrastructure
in order to ensure their standards of life at a certain and acceptable level for theirsustainable development.
Lacking functional areas because of limited land fund is a common feature ofuniversities located in Hanoi. There are several universities with the average landarea per student is just around 2m2/student (Phan Duong, 2009). As a result, mostof universities in Hanoi do not have a large dormitory that can serve the need of
their students. According to (Phan Duong 2009), the total areas of dormitories
available in Hanoi can only meet about 15-20% the demand from students. Yet
these universities cannot afford an extension of their dormitories due to financial
and land fund issues. Most of the universities in Hanoi posses only less than 10 haof their areas, especially there are three universities having only an area of lessthan 1 ha. With about 80% students from outside the city, apart from the ones whostay living at home and commute to the universities and the ones who live with
their relatives in the city, there is still a lot of unmet demand for rental houses forstudents in Hanoi (Students from NEU, 2006).
Being provided and managed by households and private developers, privatehouses for rent, including student rentals in Hanoi has been considered as acomplicated and unsafe, low quality sector. This paper, based on an empiricalsurvey, looks into the practices of safety and securities in private student rentals in
Hanoi in order to point out factors related to safety and security issues inresidential rentals and their impact levels. It then measures the level of risk thateach safety and security factors may create to student tenants in Hanoi (hereafterreferred to as safety/security risk with its negative meaning) and the role ofsafety/security risk consideration on their accommodation choice from the tenants’perspective.
2. THE RESEARCH METHODOLOGY
The paper uses results from a survey with respondents who are students fromdifferent universities and colleges in the city of Hanoi to investigate the issues instudent rentals in terms of safety and security. A total of 30 questions were includedin the questionnaire. The factors to be measured in the questions have beendeveloped from interim results collected in a preliminary survey through unofficial
talks with 20 students from the researchers’ faculty. The respondents are requested
to answer the questions regarding their own experience living in private rentals. 184
questionnaires were sent back with a wide range of participants’ age, rental location,
gender, and hometown (Table 1). Among them, 140 questionnaire were done with
self-completion method, the others were filled in an online survey. Participants ofthe survey age from 18 to 24, with an average a number of 20.95. Among theparticipants, apart from 40 people (21.74%) refusing to give information on their84

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age, the female respondents account for 33.15% while the male students constitute45.11%.
Table 1: The survey participants classification
No
1
1.1
1.2
1.3
2
2.1
2.2
2.3
2.4
2.5

Categories
GenderMale
FemaleNot answer
Hometown
Rural areas
Small towns
Class II cities
Class I and special cities
Not answer
Total

No of respondents

%

83
61
40

45.11
33.15
21.74

96
26
27
10
25
184

52.17
14.13
14.67
5.43
13.59
100.00The collected data was transcribed and analyzed using SPSS software and Excel.
The research results are analyzed and discussed in the next sections.
3. INFLUENTIAL FACTORS TO SAFETY AND SECURITY RISKS:CATEGORIES AND LEVELS OF IMPACT TO STUDENT TENANTS
There are 13 factors (generated from the preliminary survey), coded from
Factor_A to Factor_N, being investigated in the study to measure their impact onsafety and security of the students in rentals properties (Table 2). There areseveral new factors emerged from the data, but their rates of happening are verylow (less than 1%), therefore, they are not included to be analyzed in the study.
The figures in Table 2 show the percentage of respondents who claimed that thefactors have happened and brought safety/security risks to some or many of the
respondents.
Table 2: Common influential factors to safety/security risks of student tenants
No

Factor Code1

Factor_A

2

Factor_B

3
4
5
6
7

Factor_C
Factor_D
Factor_E
Factor_F
Factor_G

Influential Factors to Safety/Security
Risks
Structural quality and life of rental
properties
Security quality of rental properties(doors, windows, locks, roofs, security
equipment provided, etc..)
Equipment quality in rental properties
Roommates/flatmates
Tenants in surrounding rental properties
Landlords
People live surrounding the rental
properties

Rate ofhappening
7.10%
18.00%
9.30%
9.30%
7.10%
8.20%
6.00%

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No

Factor Code

8
9
10
11

Factor_H
Factor_I
Factor_K
Factor_L

12

Factor_M

13

Factor_N

Influential Factors to Safety/Security
Risks
Properties’ visitors
Security issues in neighborhood areas
Location of the properties
Quality of surrounding
buildings/construction works
The construction of new construction
works near the properties
Natural environment

Rate ofhappening
5.50%
13.10%
8.20%
4.90%
3.90%
4.90%

Among the factors, Factor_B (security quality of rental properties) and Factor_I(security issues in neighborhood areas) are the ones to be considered as the mostcommon factors to bring safety/security risk to student tenants with the rate ofhappening to the survey participants as 18.00% and 13.10% respectively. Othersignificant and commonly happened factors include Factor_F (landlords),
Factor_K (location of the properties), Factor_C (equipment quality in rental
properties) and Factor_D (roommates/flatmates). There is a surprise that thelandlords have become a common influential factor negatively impacting safety
and security issues of student tenants.
Each factor will also be measured its level of influence with three different scales:high impact (score 2), low impact (score 1), no impact (score 0). The average
influential levels of each factor then are calculated and presented in Table 3.
Table 3: Impact levels of influential factors
No

Factor Code

1
2
3
4
5
6
7
8
9
10
11
12
13

Factor_A
Factor_B
Factor_C
Factor_D
Factor_E
Factor_F
Factor_G
Factor_H
Factor_I
Factor_K
Factor_L
Factor_M
Factor_N

No
impact
4.35%
1.10%
3.30%
9.20%
5.45%
12.60%
6.60%
12.50%
2.20%
2.70%
24.00%
26.25%
10.90%

Low
Impact35.35%
6.00%
44.30%
32.60%
49.20%
40.40%
54.10%
53.10%
12.50%
40.80%
54.10%
55.75%
47.00%

High
Average Impact
ImpactLevel
60.30%
1.56
92.90%
1.92
52.50%
1.49
58.20%
1.49
45.35%
1.40
47.00%
1.34
39.30%
1.33
34.40%
1.22
85.30%
1.83
56.50%
1.54
21.90%
0.98
18.00%
0.92
42.10%
1.31

According to Table 3, most of the influential factors (11 out of 13) are considered
as having low to high impacts to the student tenants. Factor_B and Factor_I, themost commonly influential factors are also the ones that have greatest impact withthe average impact level of 1.92 and 1.83 respectively. What the survey
respondents have experienced with these factors may explain this result, since86

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people tend to judge things more seriously based on their own experiences than
prediction. Factor_A, Factor_K are the other two that come into the top five.
Factor_L (quality of surrounding buildings/construction works) and Factor_M(the construction of new construction works near the properties) are the ones withthe lowest average impact level, of only 0.98 and 0.92 respectively. Though morethan 50% of the respondents have considered those factors as having low impact
on their safety/security risks, a certain percentage of them do not consider thesefactors as having high impact, therefore, the factors generally become having very
low impact on student tenants’ safety and security. The fact that the least numberof respondents having experienced consequences of these factors (rate ofcommonly happening ranked 12th and 13th in Table 2) can explain this researchoutcome.
Being ranked with the 6th position in Table 2 in terms of rate of commonly
happening, Factor_A (structural quality and life of rental properties) jumps up to
position 3 in terms of average impact level, passing Factor_C (equipment quality
in rental properties), Factor_D (roommates/flatmates), Factor_F (landlords) andFactor_K (location of the properties). “Structural quality and life of rental
properties”, therefore, is considered as having high impact to student tenants’safety/security risks. “Location of the properties”, with average impact level of
1.54, has become the fourth factor harming badly to the survey participants. With
the average impact levels ranging from 1.49 down to 1.22, “equipment quality inrental properties”, “roommates/flatmates”, “tenants in surrounding rental
properties”, “landlords”, “people live surrounding the rental properties”, “naturalenvironment” and “properties’ visitors” are considered as having average impact
on tenants’ safety and security. “Equipment quality in rental properties” and“roommates/flatmates”, which have both brought safety/security issues to 9.3% of
the respondents, have been thought generating comparably high safety impact tothe students. The “landlords”, then “tenants in surrounding rental properties”, as8.2% and 7.1% respondents have had issues with (see Table 2), are still
considered as creating average impact on student tenants’ safety/security risk
(average impact level 1.34 and 1.40 respectively) .
Taking the past figures of rate of happening as the probability of occurrence foreach influential factor to safety/security risks, expected risk level then arecalculated and presented in Table 4. Figures in Table 4 are sorted in thedescending order of risk levels. Seven factors (Factor_B, Factor_I, Factor_C,
Factor_D, Factor_K, Factor_A, Factor_F) have highest risk level, more than 10%.
These are the ones which need paying attention to when examining the student
rental accommodation. Among them, “security quality of rental properties” and“security issues in neighborhood areas” (Factor_B and Factor_I) are the ones thatneed to be managed properly due to their substantial high risk levels.
Table 4: Risk levels analysis
No

Factor Code1
2

Factor_B
Factor_I

Probability ofoccurrence
18.00%
13.10%

Average
Impact1.92
1.83

Risk Level
34.52%
23.99%

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No

Factor Code

3
4
5
6
7
8
9
10
11
12
13

Factor_C
Factor_D
Factor_K
Factor_A
Factor_F
Factor_E
Factor_G
Factor_H
Factor_N
Factor_L
Factor_M

Probability ofoccurrence
9.30%
9.30%
8.20%
7.10%
8.20%
7.10%
6.00%
5.50%
4.90%
4.90%
3.90%

Average
Impact
1.49
1.49
1.54
1.56
1.34
1.40
1.33
1.22
1.31
0.98
0.92

Risk Level
13.87%
13.86%
12.61%
11.07%
11.02%
9.93%
7.96%
6.70%
6.43%
4.80%
3.58%

4. CRITERIA FOR STUDENTS’ RENTAL ACCOMMODATION CHOICE
AND THE LEVEL OF IMPORTANCE OF SAFETY/SECURITY RISKFACTORS TO THE RENTAL DECISION-MAKING
4.1 Criteria for rental accommodation choice of students in Hanoi
The survey respondents were asked for factors that can influence their rental choice.
Seventeen factors have emerged from the survey results as significant criteria foraccommodation choice of student tenants in Hanoi (Table 5). There are still several
criteria being mentioned by a couple of respondents, yet due to the low rate of
emergence (less than 5%), they are excluded from the analysis. There is a surprisethat “living with friends/beloved people” is considered as one of the top fiveimportant factors by only 22.28% of the respondents, having the lowest rank in the
Table. Among those seventeen criteria, there are 10 factors having rate of being
mentioned from 50% upward. The results show that, rent is the most significant
perceived factor, as being considered by 99.42% of the survey participants as one of
the important factors (out of the total number of respondents who answered therelevant question, not including the ones who have refused). For more details, thesurvey participants have a tendency to look for a property with monthly rental priceof under 1,600,000 VND (~76 USD) with approximately 18m2 area. In order tominimize the rent, 83.7% of interviewees choose to share the house with otherstudents. Individual rent, therefore is estimated averagely at 839,505 VND (~40
USD) per person per month. In addition, not many landlords in Hanoi requiretenants to pay a deposit or they require only the a minimum deposit of about
600,000 VND, less than a monthly rent.
The next significant factors include “distance to university/college” (Criterion_B),“quality of the property” (Criterion_E), “safety and security issues in the rental
properties” (Criterion_R) and “rental area” (Criterion_D). A percentage of
81.87 % of the respondents considered “distance to university/college” as acriterion for rental choice. This is reasonable because students commute mainly
by bus and bike. Moreover, because of frequent traffic congestion in capital,
tenants want a property in the proximity of the school. “Quality of the property”
aspect is also used by 81.87% of the survey participants when choosing a place to88

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rent while 76.02% of them chose to take into account the “rental area”. That
sharing a rental property can help tenants to save money means they have to accept
smaller area. According to the data, in average, every 2.44 tenant shares a rental
property which is 21.65 m2 in area. Therefore, each student haves a limited area of
9.56 m2 for accommodation. Besides “rent”, “quality of the property” and“distance to university/college”, “safety and security issues in the rental properties”
is agreed by 81.29% of the respondents who replied to the relevant question as animportant factor to be used for rental decision. It is noted that this factor, safety
and security issues in the rental properties, belongs to the top five factors that havegreatest rate of being considered as important criteria to accommodation choice ofstudent tenants in the research.
Table 5: The criteria for accommodation choiceNo

Criterion
Code

1
2
3
4
5
6

Criterion_A
Criterion_B
Criterion_C
Criterion_D
Criterion_E
Criterion_F

7
8
9
10
11
12
13
14
15
16
17

Accommodation Choice
Criteria

Rent
Distance to university/college
Availability of commuting means
Rental area
Quality of the property
Property equipped facilities(equipment, internet access, TV
license, etc…)
Criterion_G Property regulation level of strict
Criterion_H Landlord’s sharing flat
Criterion_I
Availability and quality ofkitchen, WC etc.,
Criterion_K Sharing room with others
Criterion_L Rate of power cut-off
Criterion_M Water supply
Criterion_N Tenants in surrounding rental
properties
Criterion_O People live surrounding the rental
properties
Criterion_P Surrounding natural environment
Criterion_Q Living with friends/beloved
peopleCriterion_R Safety and security issues in therental properties

Rate of being
considered as animportant criterion
99.42%
81.87%
56.73%
76.02%
81.87%
67.84%
53.80%
49.71%
64.33%
40.35%
45.03%
50.88%
46.20%
33.92%
36.84%
23.98%
81.29%In terms of the weights that respondents gave to each criterion, it is observed thatthey have a very wide range. Table 6 shows the maximum value of the weights
recorded from the survey for each criterion in terms of contribution to theaccommodation decision and their mean values. Data in Table 5 reveals that there
is no criterion being considered as important by all of the respondents, even rent(one person did not choose rent as an criterion for his/her accommodation
decision). Yet rent is still considered as the most influential factor to the
Sustainable safety and security in private rental properties for students in Hanoi:
Sustainable safety and security in private rental properties for students in Hanoi. . . . . .
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respondents’ accommodation decision with the maximum weight of 80% and amean value of 31.13%, comparably greater than other factors (Table 6). “Safety
and security issues in the rental properties” is the next great contributor toaccommodation decision with the maximum weight recorded of 50% and a meanvalue of 12.08%. “Living with friends/beloved people” seems to vary a lot, withthe maximum weight noted of 50% but the mean value is only 1.66%. This figure
shows different points of view of students in their choices for accommodation.
Table 6: The criteria’s weights to accommodation decision
No
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

Criterion CodeCriterion_A
Criterion_B
Criterion_C
Criterion_D
Criterion_E
Criterion_F
Criterion_G
Criterion_H
Criterion_I
Criterion_K
Criterion_L
Criterion_M
Criterion_N
Criterion_O
Criterion_P
Criterion_Q
Criterion_R
Total

Maximum weight
80%
30%
30%
30%
35%
30%
40%
25%
30%
30%
10%
15%
20%
10%
50%
30%
50%

Mean of weight
31.13%
7.59%
3.62%
6.40%
9.55%
4.33%
3.30%
2.90%
5.67%
2.27%
2.22%
2.79%
2.04%
0.97%
1.66%
1.48%
12.08%
100.00%4.2 Factors that bring safety/security risks to student tenants and their levelof importance to accommodation choice
It is noted that besides “safety and security issues in the rental properties”, there
are a lot of factors that can bring in safety/security risks to student tenants
appearing as criteria to accommodation choice of the survey participants, such as“quality of the property”, “landlords’ sharing flat”, “tenants in surrounding rental
properties”, “people live surrounding the rental properties”, “surrounding naturalenvironment” etc., with significant percentage of the respondents considered themas important. Table 7 looks into this further by list out the aspects ofsafety/security risks (see Table 2 for the description of each factor code) in termsof their importance to accommodation choice. Respondents were asked to choose
their own list of top five important factors to their rental choice. Scores are given
to the factors with 5 for the most important and 1 for the least important factor.
The average level of importance for each factor then is calculated by taking themean of their importance scores.

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Table 7: The safety/security risk factors in terms of level of importance toaccommodation choiceNo

Factor Code

1
2
3
4
5
6
7
8
9
10
11
12
13

Factor_A
Factor_B
Factor_C
Factor_D
Factor_E
Factor_F
Factor_G
Factor_H
Factor_I
Factor_K
Factor_L
Factor_M
Factor_N

Frequency to be included in
top five important factors
58.64%
89.51%
40.74%
35.19%
43.83%
27.78%
26.54%
22.22%
71.60%
39.51%
5.56%
9.88%
22.84%

Average level ofimportance
2.01
3.55
1.09
1.02
1.32
0.65
0.54
0.50
2.56
0.94
0.09
0.19
0.41

According to the data, the top five most mentioned factors include Factor_B(security quality of rental properties), Factor_I (security issues in neighborhood
areas), Factor _A (structural quality and life of rental properties), Factor_E (tenantsin surrounding rental properties) and Factor_C (equipment quality in rental
properties). These also are the ones which have greatest average level of importanceaccordingly. Among them, “security quality of rental properties” (Factor_B) and“security issues in neighborhood areas” (Factor_I) become the most importantfactors which have average level of importance to the rental choice of more than
2.5/5. This has confirmed their high level of impact as discussed in Section 3. Again,
Factor_L (quality of surrounding buildings/construction works) and Factor_M (theconstruction of new construction works near the properties) which are with thelowest average impact level (Table 3), have lowest frequency to be included in the
top five important factors as well as the average level of importance. The results
show a consistency in the data collected from the survey.
4.3 Trade-off between bearing
accommodation choice criteria

safety/security

risks

and

selected

A certain percentage of 80.8% of the respondents who replied to a relevant
questions in the questionnaire do not choose a location with more safety/security
risks to have a lower rent. Other 33 people (19.2%) may consider the trade-off but
only with a substantial reduction in rent (33.5%). In terms of leveraging the distanceto university/college and safety/security risk, there are 108 out of 173 survey
participants (62.4%) refusing to live in low-security areas in proximity of their
university/college whereas the others accept. Though a limited number of them (lessthan 25%) did not consider living with friend/beloved people as very important,
56.40% of 172 people who have responded to the relevant questions may accept a
trade-off between bearing more safety/security risks and living with friend/beloved
people, 15.12% of them will definitely accept and only 28.49% of them refuse thetrade-off.
Sustainable safety and security in private rental properties for students in Hanoi:
Sustainable safety and security in private rental properties for students in Hanoi. . . . . .
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5. CONCLUSIONS AND RECOMMENDATIONS
Looking into the safety/security risk issues of student rentals in Hanoi under thetenants’ perspective, this research has found out that there are thirteen factors thatcan significantly bring risks to the tenants’ life in rental accommodation. Seventeen
criteria have been selected by the respondents as important factors influencing theirrental accommodation choice. The top six mostly happened influential factors tosafety/security risks include “Security quality of rental properties”, “Security issues
in neighborhood areas”, “Equipment quality in rental properties”,“Roommates/flatmates”, “Location of the properties” and “Landlords” (the last two
have the same rate of happening). The top six with highest average impact level are“Security quality of rental properties”, “Security issues in neighborhood areas”,“Structural quality and life of rental properties”, “Location of the properties”,“Equipment quality in rental properties” and “Roommates/flatmates” (again, the last
two have the same figures). With both greatest impact level and occurrence
probability, “security quality of rental properties” and “security issues inneighborhood areas” become the highest risks for tenants as students. “Location of
the properties” and “Roommates/flatmates” are the next ones with both great impact
level and frequency of happening. This implies that the student tenants need to pay
most attention to those issues in order to reduce and manage properly theirsafety/security risks. The landlords also need to care about those issues to attract
and protect their tenants.
Regarding the criteria for rental accommodation choice, besides “rent”, “quality ofthe property” and “distance to university/college ”, “safety and security issues in therental properties” goes in the top five aspects that have been considered asimportant to accommodation choice. It is noted that there are a lot of criteria thatcan bring in safety/security risks to student tenants appearing as criteria to
accommodation choice of the survey participants. All of these criteria, when being
analyzed under the influential factors to safety/security risks, have contributed tothe importance of safety/security risks consideration in student rental
accommodation choice. Again, “security quality of rental properties” and “security
issues in neighborhood areas” become the most important factors which havegreatest average level of importance to the rental choice. In addition, students do notcare much about trade-off between bearing safety/security risks and selectedaccommodation choice criteria.
This paper adds in the need of raising attention from the landlords, the tenants andeven the government authorities in providing safe and sustainable accommodation
to student tenants in order to have their contribution to the development of thisrental market as well as the sustainable development of this type of urban citizens.
REFERENCES
Phan Duong, 2009. Land for universities in Hanoi: too limited. Vietnam Economy
Students from NEU, 2006. Student research report: student rentals: practice andsolutions. Hanoi, NEU.

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Tsunami evacuation facilities in the damaged
areas due to the Great East Japan Earthquake:
before and after
Osamu MURAO
Professor, International Research Institute of Disaster Science
Tohoku University, Japanmurao@irides.tohoku.ac.jp
ABSTRACT
Vertical evacuation is a very critical countermeasure to prevent damage toresidents in tsunami-prone areas from devastating tsunami. There are two types
of tsunami evacuation facilities; tsunami evacuation buildings and towers. How
they are used will be a very significant matter in tsunami-prone low-lying areas toreduce tsunami casualties in the future. This paper reports those construction
conditions in the damaged areas due to the Great East Japan Earthquake andTsunami as of March 2011, and how they were used just after the occurrence oftsunamis. It also presents the recent construction situation and tsunami
evacuation strategies through the recovery process after the event. The key
findings of the research are as follows: (1) there were 111 tsunami evacuationbuildings and no tower in the damaged areas as of March 2011, (2) the number ofbuildings and towers became 255 and 4 respectively, and (3) construction
situations vary with the damage and recovery conditions. Problems andrecommendations should be shared among every coastal district in Japan.
Keywords: 2011 Great East Japan Earthquake and Tsunami, tsunami evacuationbuilding, tsunami evacuation tower, vertical evacuation, urban recovery
1. INTRODUCTION
The great earthquake on March 11, 2011 caused great tsunamis to the coastal
areas in Tohoku Region in Japan. The death toll by the event, mainly by thetsunamis, went up to 18,493, but some victims might have survived the tsunamis
if those areas had adopted proper evacuation system according to geographic
characteristics. This paper explains the meaning of vertical evacuation system,
which mainly employs tsunami evacuation construction, and its background inJapan at first. Then it reports how many tsunami evacuation facilities existed andhow they worked in the affected coastal areas, Aomori, Iwate, Miyagi, Fukushima,
Ibaraki, and Chiba, when the tsunamis hit. Finally it refers to how they have been
increasing since 2011 and examines regional differences of those situations.

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2. BACKGROUND OF TSUNAMI DISASTER REDUCTIONSTRATEGIES WITH EVACUATION CONSTRUCTION IN JAPAN2.1 Vertical evacuation
There are two types of evacuation from tsunami; horizontal and verticalevacuation. NOAA et.al (2001) define them in “Designing for Tsunamis” asfollows:
 horizontal evacuation—moving people to more distant locations or higher
ground.
 vertical evacuation—moving people to higher floors in buildings.
2.2 Vertical evacuation
Tsunami evacuation strategies should correspond to each geographical conditionand land use regulation. Vertical evacuation systems are necessary for immediate
escape in low-lying areas such as Sendai or Natori in Sendai Plain. There arebasically two types of vertical evacuation facilities as shown in Figure 1; tsunami
evacuation buildings and tsunami evacuation tower.
Vertical Evacuation
by Tsunami Evacuation Building
Horizontal
Evacuation

Land

Vertical Evacuation
by Tsunami Evacuation Tower
Tsunami Water

Figure 1: Horizontal evacuation and two types of vertical evacuation
People can escape from coming tsunami into any kind of buildings if it is stronger
and higher than the tsunami. However, some of them might be inappropriate to be
designated in advance because of lack of space or privacy in daily life. Then local
governments usually designate appropriate buildings as “designated tsunami
evacuation building” according to estimated tsunami height, building structural
type and the number of stories in Japan. It may be an high-rise apartment, anelementary school, a hospital, or a government office building. Figure 2 shows adesignated tsunami evacuation building in Fujisawa City, Kanagawa Prefecture.
On the other hand, tsunami evacuation tower is the one constructed by a local
government in order to save people in the tsunami high-risk districts. This kind of
structure tends to be located in the low-lying areas, where finding existing properbuildings for vertical evacuation is difficult. Figure 3 shows tsunami evacuation
towers in Fujisawa City, Kanagawa Prefecture, and Kushimoto, Wakayama
Prefecture.

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Figure 2: Designated tsunami evacuation building in Fujisawa, Kanagawa(a) in Fujisawa, Kanagawa(b) in Kushimoto, Wakayama

Figure 3: Tsunami evacuation towers
2.3 Tsunami Disaster Reduction Strategies in JapanWe Japanese people, living in the earthquake-prone country surrounded by ocean,
have experienced huge tsunamis since ancient times. The first systematic tsunami
disaster strategy in the 20th century was shown in “Advisory Report for Tsunami
Disaster Prevention” by Council for Earthquake Disaster Prevention (1933). It
contains relocation to higher land, seawall, tsunami control forest, piers, building
regulation, buffer zone, evacuation route, warning system, and commemoration
project. This triggered construction of piers and tsunami control forest in someplaces.
Tsunami disaster reduction strategies were actively examined after World War II.
The tsunami forecast started in the 1950s. The construction for tsunami
mitigation such as levees or seawalls was accelerated after the 1960 Chilean
Tsunami. In the 1970s, disaster reduction human activities began: tsunami
inundation maps were made, tsunami information system was established, andtsunami education activities were carried out. Although the vertical evacuation
strategies were not widely employed in the 1980s, Fujisawa City started toconclude MOU for “designated tsunami evacuation buildings” with about fifty
private buildings.
In the 1990s, the needs of comprehensive disaster management arose socially, and“Guideline to Strengthen Tsunami Disaster Management in Local Plan for
Disaster Prevention” was released (National Land Agency et al., 1997). This
Tsunamifacilities
evacuation
facilities
in thedamageddue to2011
Great
East Japan
Tsunami evacuationin thedamagedareas
due to areas
the Great
East
Japan
Earthquake:
Earthquake:
beforeandafter
before and after95

October
2013, 2013,
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Vietnamcontained basic ideas, basic policy, and planning process for tsunami disastermanagement based on Japanese experience. It refers to tsunami evacuationbuilding utilization, but it is not as a comprehensive vertical evacuation system.
The Great Kobe Earthquake was the most devastating urban disaster that hit
modernized cities in the 20th century, and it influenced future disastermanagement in many fields. One of the remarkable evolutions could be seen in
the spatial information technology. The spread of Geographic Information
System affected the disaster management field, and it changed the way of making
hazard maps in community level. Then Cabinet Office (CAO), et al. (2004)
published “Tsunami and Tidal Wave Hazard Map Making Manual” for coastal
areas. “Guideline for Management of Tsunami Evacuation Buildings,” which
enlarges on tsunami evacuation building management, was released by CAO(2005) next year.
Since then, the local governments facing the Pacific Ocean in East Japan had
prepared tsunami evacuation facilities as well as those in West Japan. However,
the huge tsunamis caused by the Great East Japan Earthquake attacked thosecoastal areas.
3. SITUATION OF TSUNAMI EVACUATION CONSTRUCTION AS OF
MARCH 2011
3.1 Interview
In order to compile information of the tsunami evacuation construction situationin the damaged areas as of March 2011 and August 2013, telephone interviews
with the local governments were conducted as follows:
Date:
August 6-19, 2013
Interviewees: 70 local governments located in front of the Pacific Ocean in
Aomori, Iwate, Miyagi, Fukushima, Ibaraki, and Chiba Prefecture
Questions:
1. the number of tsunami evacuation facilities as of March 2011
2. what happened concerning tsunami evacuation facilities
3. the number of tsunami evacuation facilities as of August 2013
4. problems they faced
3.2 The number of tsunami evacuation facilities as of March 2011
As a result of the interviews, the number of tsunami evacuation facilities,buildings and towers, as of March 2011 and August 2013 in terms of prefecture isshown in Table 1. The situation as of March 2011 is examined in this chapter.
There was no tower in the seven prefectures in those days. On the other hand,
there were 111 tsunami evacuation buildings in the damaged prefectures except
Fukushima and Ibaraki. The most buildings, sixty two, existed in Chiba followed
by Miyagi with 45. There were only two buildings in Aomori and Iwate
respectively.

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Table 1: The number of tsunami evacuation facilities as of March 2011 andAugust 2013 in terms of prefecture
Prefecture
Aomori
Iwate
Miyagi
Fukushima
Ibaraki
Chiba
Total

Tsunami Evacuation Buildings
March 2011
August 2013
2
20
2
1
45
29
0
0
0
28
62
177
111
255

Tsunami Evacuation Towers
March 2011
August 2013
0
0
0
0
0
1
0
0
0
0
0
3
0
4

Table 2 demonstrates the number of tsunami evacuation buildings as of March2011 and August 2013 in terms of local governments, and future challenges. The
municipalities with no building is not included in the table.
Focusing on the number of local governments that had the buildings, Chiba
prefecture had ten followed by Miyagi with eight. Aomori and Iwate had onlyone.
As for the number of buildings in each local government, the most buildings, 22,
were in Shirako Town, followed by 18 in Tateyama City, in a few damaged Chiba
Prefecture. In the devastated Tohoku prefectures, there were 15 buildings in
Kesen-numa City and 12 buildings in Tagajo City.
3.3 Evacuation situation just after the tsunamis on March 11, 2011
Most buildings were helpfully used more or less after the event according to thesurvey. Especially in severely damaged Kesen-numa, Minami-Sanriku, Shiogama,
Tagajo, hundreds or thousands of people escaped to the buildings and survived. Itmeans that most existing designated tsunami evacuation buildings functioned as
expected.
On the other hand, some buildings did not work for survival because ofdestruction. One building was washed away in Sendai, and another building was
not high enough to save people from the huge tsunami in Natori.
The damage situation was not critical from the viewpoint of evacuation in Chiba,
but the data indicates many buildings usefully worked for the affected people.
One good practice was the fact that the usual evacuation drill they had carried out
was effective to escape in Yokoshiba-hikari.
4. SITUATION OF TSUNAMI EVACUATION CONSTRUCTION AS OF
AUGUST 2013
Each local government has increased the number of tsunami evacuation facilities
in water front areas since the earthquake, but there are differences depending on
their recovery process or geological situation. Hereafter, recent construction
situation will be discussed based on the acquired information by the interviews.

Tsunamifacilities
evacuation
facilities
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Great
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Tsunami evacuationin thedamagedareas
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Table 2: The number of tsunami evacuation buildings as of March 2011 andAugust 2013 in terms of local governments, and future challenges
Prefecture
Aomori

Municipality

Iwate

HironoHachinohe

KamaishiMiyagi
Kesen-numa

Minami-sanriku
Ishinomaki

Higashi-matsushima
Shiogama
TagajoSendaiNatori
Ibaraki
Chiba

KamisuChoshi
Asahi
Yokoshibahikari
Sanmu
KujukuriOamishirasato

ShirakoIchinomiya
Isumi
OnjukuKatsuura

Kamogawa

Minamiboso
Tateyama
Total

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Aug-13 Policies and Challenges on Tsunami Evacuation Facilities
Some Tsunami Evacuation Buildings were newly designated, based on the2
20 maximum Tsunami inundation map published by Aomori Prefecture, in October.
0
1 No new plan to designate due to the lack of tall buildings along the shore.
Prioritize alerting the residents higher ground evacuation over evacuating toTsunami Evacuation Buildings. Designation of 2 buildings was removed after the2
0 disaster.
In the area where people have difficulty in evacuation, Tsunami Evacuation
Buildings are planned to be a solution. When the disaster occurred, the evacuees at
the Tsunami Evacuation Buildings couldn't get out of the buildings due to the fire15
2 that broke out.
Higher ground evacuation is more acknowledged than evacuation facilities. It was
better if there were stocks and generators at the Evacuation Buildings when the4
0 disaster occurred.
On Tsunami Evacuation Buildings, there are restrictions because of the use ofprivate facilities. To secure enough land and funds is a challenge to build towers.
3
4 Deal with the specific issues as the reconstruction goes.
Overall evacuation plans are being reconsidered. The designation of the Tsunami
Evacuation Buildings was removed due to the damage the buildings got. The useof private facilities are under consideration, including new designations. One of2
0 the concerns is if the construction of seawalls will go smoothly.
More Tsunami Evacuation Buildings are planned to be constructed since there isn't
4
4 enough.
More designation is planned because of the lack of Tsunami Evacuation Buildings.
12
16 When the disaster occurred, supply/food stocks weren't enough in these buildings.
Both of the buildings and towers are needed to be designated/constructed as soon
2
1 as possible because of the lack of these facilities.
Today, community planning toward reconstruction is progressing, which is related
to Tsunami evacuation planning. The current designated Tsunami Evacuation
3
2 buildings, an elementary school and junior high school, will be broken down.
Because of the low land overall, the city proactively call for designation to privatecompanies, and also there were offers to designate from private businesses. The028 city has 40 more places available for evacuation except the private facilities.
If there are facilities willing to be designated, more Tsunami Evacuation Buildings
0
8 are essential. Communicating information smoothly is a key.
Response to the residents after evacuating to Tsunami Evacuation Buildings need1
8 to be considered.
Some issues need to be solved: ways of guiding evacuees in the case of Tsunami
occurrence at night or on holidays, or securing electricity. To raise residents'
4
4 awareness of evacuation is essential.
No plan to designate more buildings. All the tall buildings on the coast werealready designated. Stairs are planned to be built attached to 2 schools by the coast1
5 for rooftop evacuation. Disaster drills are carried out after the Tsunami.
Had been collecting the basic data. Evacuation procedures will be reconsidered.
0
5 Plans on concluding an agreement on temporary staffing upon disaster occurrence.
One of the current designated Tsunami Evacuation Buildings were underdiscussion when the earthquake hit. Plans on new buildings or towers are on holdsince the predicted flood map published by Chiba Prefecture doesn't meet the0
4 policy of Ministry of Land, Infrastructure, Transport and Tourism.
Buildings under construction in the coastal area. Evacuation procedures, including
evacuee guidance and evacuation by cars through narrow streets, will be
22
29 considered.
No tall buildings in the coastal area, which needs to be improved. Designation of
Tsunami evacuation routes is considered. The downside of the designation is it
may cause traffic issues on those routs due to a small number of primary roads that5
9 goes from the east to the west.
Problems such as ensuring lands for tower constructions and evacuation roads
1
4 need to be solved. The priority of the measures is discussed with the residents.
0
7 Make the use of 7 currently designated Tsunami Evacuation Buildings.
Comprehensive evacuation measures need to be considered, including all types of0
10 temporal evacuation facilities.
Disaster drills are carried out in the area with not enough land for building
Tsunami evacuation facilities. Chiba Prefecture announced the prediction on
Tsunami; about 8 meter high Tsunami would reach Tateyama area in 8-10minutes.
Based on the prediction, a goal has been set to evacuate to sites with 10 meters
above sea level or higher in 10 minutes. In order to raise awareness of evacuationin the daily life, each municipality is putting up sea-level signs (240 signs up in
1
44 total.)Finished designation of Tsunami Evacuation Buildings in the city. Planning on
designating a Children's Center on higher ground. Measures for big crowds, such9
22 as firework events, need to be considered.
Each region are holding disaster drills to escape to higher ground than the18
18 predicted Tsunami height.
111
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4.1 The number of tsunami evacuation facilities as of August 2013
Table 1 also shows the change of the number of tsunami evacuation facilities
between March 2011 and August 2013. The total number of buildings became
255 from 111, which means more than double. Regarding to each prefecture, thenumber of buildings increased by 18 to 20 in Aomori, by 28 from 0 in Ibaraki, andby 115 to 177 in Chiba; the number decreased by 1 from 2 in Iwate, and by 16 to
29 in Miyagi. In Fukushima remains 0.
As for tsunami evacuation towers, the total number was quite small: one tower
was constructed in Miyagi, and three in Chiba.
4.2 Problems and future challenges of tsunami evacuation facilities
Table 2 includes the policies and challenges on tsunami evacuation facilities
clarified by the interviews. Because the tendency of the construction and current
policy with regard to tsunami evacuation system depends on the circumstances
around each district and its recovery plan related to the damage level, this session
examines the problems and future challenges prefecture by prefecture.
Municipalities in Fukushima do not have concrete vision on the evacuation
facilities because of the difficulty of making recovery plans due to the Fukushima
Daiichi nuclear disaster.
In Iwate, there were only two designated evacuation buildings in Kamaishi, butboth were cancelled after the event because of the inundation and destruction by
the tsunami. Although Hirono Town designated one building, the others did nothave a plan to have evacuation buildings yet in near future. It is probably becauseof the rias geography surrounded by mountains.
Miyagi has Sendai Plain in the south, and this geographic characteristic
differentiates its construction situation from Iwate’s. Southern local governments,
Matsushima, Shiogama, Tagajo, Sendai had already increased or planned to havetsunami evacuation facilities. However, we can see some similarities to Iwate.
They cannot discuss concrete evacuation plans in Kesen-numa, Minami Sanriku,
Higashi Matsushima, and Natori City until the new districts are designed
concretely.
Following above three prefectures in Tohoku Region, the cities in Ibaraki werealso severely damaged. However the damage level was less than those in Tohoku,
so their most concern is not the recovery from washed-away districts but
improvement of the existing districts. According to Table 2, Hitachinaka andOarai are focusing on the evacuation to higher lands, and Kamisu City, located on
low-lying ground, had already designated 28 tsunami evacuation buildings since2011.
Damage to the districts by the tsunami in Aomori and Chiba was not significant.
However, the construction situation is different. The number of existing tsunami
buildings as of March 2011 was only two in Aomori, but it became 18 in August
2013.
Chiba Prefecture had the biggest number of buildings among the objective
prefectures. In addition to them, they constructed 115 buildings by August 2013.
The active situation may be related to its dense location, close to Tokyo, andgeographical condition by the long coast of Kujukuri Beach.

Tsunamifacilities
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facilities
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Tsunami evacuationin thedamagedareas
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5. CONCLUSION
This paper reports the construction situation of tsunami evacuation buildings andtowers in the damaged areas due to the Great East Japan Earthquake and Tsunami
as of March 2011, and how they were used just after the occurrence of thetsunamis. It also presents the recent construction situation and tsunami evacuation
strategies through the recovery process after the event. The key findings of theresearch are as follows: (1) there were 111 tsunami evacuation buildings and notower in the damaged areas as of March 2011, (2) the number of buildings andtowers became 255 and 4 respectively, and (3) construction situations vary withthe damage and recovery conditions. Problems and recommendations should beshared among every coastal district in Japan.
ACKNOWLEDGEMENTS
This work was supported by the Japan Society for the Promotion of Science(JSPS) through the Grants-in-Aid for Scientific Research No. 25242036“Resilience of the Urban Recovery System after the 2011 Great East Japan
Earthquake and Regional Vulnerability Assessment to Tsunami” and No.
23404019 “Examination of Urban Recovery Plans after the 2004 Indian Ocean
Tsunami and Urban Risk Evaluation of Tsunami in Asia Influenced by Global
Warming,” and by the Organization for Promoting Urban Development Research
Grant 2012-2013 “Proposition of Tsunami Evacuation Plan in Katase District inFujisawa City.”
REFERENCES
Council for Earthquake Disaster Prevention, 1933. Advisory Report for Tsunami
Disaster Prevention. (in Japanese)
Cabinet Office, Government of Japan (CAO), et al., 2004. Tsunami and Tidal
Wave Hazard Map Making Manual (in Japanese)
Cabinet Office, Government of Japan (CAO), 2005. Guideline for Management of
Tsunami Evacuation Buildings (in Japanese)
National Land Agency et al., 1997. Guideline to Strengthen Tsunami Disaster
Management in Local Plan for Disaster Prevention. (in Japanese)
NOAA, USGS, FEMA, NSF, Alaska, California, Hawaii, Oregon, andWashington, 2001. Designing for Tsunamis Seven Principles for Planning and
Designingfor
TsunamiHazard,http://nthmphistory.pmel.noaa.gov/Designing_for_Tsunamis.pdf.

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A new parking concept for a living quarter in
Hanoi
Quang Minh NGUYEN
PhD, Faculty of Architecture and Urban Planning,
National University of Civil Engineering, Vietnam
ktsquangminh@yahoo.com
ABSTRACT
Parking systems form an integral part of any urban infrastructure, especially insuch a mega-city with a very high building density and huge number of private
vehicles as Hanoi. Parking has now become an urgent issue as the capital city
continues to expand, the number of cars and motorbikes keeps on increasing
quickly and many residents have to drive kilometers away to park and spend half
an hour or more walking home which is of course not so convenient. In mostresidential areas, there is an intersection (and also a conflict) between motorized
and non-motorized traffic flows. In view of traffic safety, this problem must be
solved as soon as possible. The fine concept car-free settlement has beendeveloped in several European towns. Among them, Vauban (Freiburg Germany) may be the best example and thus selected as a case study. The mostimportant factors for success from this pilot project as well as the applicability to
Hanoi are analyzed in the first part of the academic paper. The second part willthen focus on the spatial re-organization of a typical living quarter in Hanoi on
the basis of the periphery-and-core structure, in which the periphery can be used
for parking along with commercial activities while the core will be reserved forwalking and cycling only, instead of the mixed zone quarter as often seen
nowadays. This new paradigm will ensure a much better living quality andcontribute to the long-awaited sustainable city development in the next few
decades.
Keywords: parking system, mixed zone, car-free settlement, periphery-and-core
structure
1. INTRODUCTION
An ecological settlement is usually regarded as a miniature of an ecological city.
It is planned and built on certain eco-disciplines and encompasses a broad
spectrum of solutions, ranging from traffic, townscape, energy, water, building
material and construction technology, recycling of waste, etc. into details such as
design of the room plans and structure of the building envelope. In addition, anumber of social issues should be considered in order to achieve sustainability infull. A car-free living quarter is an outstanding (but also difficult) facet of thisbrand new concept.

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In the world there have been many eco-towns developed at different levels of
success over the past three decades, but very few of them succeeded in solving thetraffic problems with private cars and motorbikes based on the three main criteria:
safety, convenience and environment-friendliness. Most of the sustainable urban
development projects just concentrated on public transport and fuel-saving cars
without solving the problem to a further extent. In fact, in those places, car andmotorbike areas are mixed with bicycle routes and pedestrian zones. No matter
how well planned such a living quarter may be, the local people still feel that their
daily lives are affected to a certain degree: either by noise or by exhaust gas, andeven more seriously by traffic accidents that could suddenly happen to old people
crossing the road or to children playing at the corner of the street if they do not
pay due attention to the cars and motorbikes passing and even when their parents
stay somewhere around them but do not keep an eye on them. In this circumstance,
the city will no longer be a safe place for people to live in. When safety as thevery first requirement and a basic condition cannot be fulfilled, sustainability willseem almost unreal.
Car-free concept does not mean living completely without cars or stopping usingcars, because cars have become an integral part of a modern city and daily life to acertain number of people. On the contrary, people can still drive in the city but
will not park near home. This notion today will lead to the development of a new
car and motorbike parking concept in mega-cities tomorrow.
2. LESSONS FROM VAUBAN (FREIBURG, GERMANY)
Vauban is a new neighborhood in central Freiburg - a small town in the southwestof Germany - initially planned in the early 1990s on a 40-hectare site of a former
barracks of the French army and built a few years later for about 4,800 inhabitants
as a model residential area in terms of sustainability. In Vauban, solar energy isused and all houses as well as public buildings are constructed to low or ultra low
energy standards, just like all the other ecological living quarters in Germany.
However, Vauban became more successful and better known than the others for
its car-free concept - a pilot project of its kind in Europe.
Vauban is very well connected to the center and the other parts of the city with
one excellent public transport network which enables everyone to go anywhere in
the 153 km2 urban region within 20 minutes. Inside Vauban, transportation is
primarily by bicycle and/or by foot. As of 2008, over 70% of the families in
Vauban had no car, according to the statistics of the local authority (Vauban
Project Management Board, 2008). The remaining householders would like to rentor sell their cars as quickly as possible, otherwise they have to pay 18,000 EUR
per year for one family-owned car in the local garage or 3,500 EUR per year for
car-sharing charged by the local authority as an obligatory fee (or tax) for thepollution that the residents’ cars may cause. This fee is very high, of course, but
adequate, since the environmental treatment costs in fact a great deal of money.
The City Council of Freiburg has applied this policy in Vauban in order to makethe community become aware of the great advantages of living in a much simpler,
happier and healthier way without depending largely on private vehicles.

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Figure 1: Vauban as the first car-free community in Germany where the residents
feel happy and care-free with cycling and walking (Freiburg City Council, 2008)

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October
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VietnamThe Vauban experience is based on simple but very effective solutions as follows:--

Developing an excellent public transport service for external circulation: twooptions (tram and bus), in operation 24/24 a day. It takes only five minutes towalk from home to the nearest tram or bus stop. There is one tram or one bus
every ten minutes on an alternate basis. That means when one person misses a
tram, he or she has to wait only five minutes for the forthcoming bus. Anothergood thing is that the ticket is all-in-one. Furthermore, the monthly ticket fareis very reasonable: 48 EUR for adults, 36 EUR for the old people as well as
for students, and 18 EUR for children.
Encouraging all the inhabitants to cycle and to walk within the neighborhood
for a safe, clean and green environment by planning all daily and weekly
services within a short walk from home and by charging car owners a very
high parking fee. The local supermarket is located in the middle of one mainroad side to allow easy access for both cargo trucks and shopping-goers. Thus,
the local people do not often have to go shopping anywhere else by car, as
they can find and purchase almost everything they need near homes. The otherpublic buildings and facilities are not far from home either, just five minutes’
walk. With regard to the car parking fee for one four-member family withhusband, wife and two children selected as a case study, they have to pay
18,000 EUR a year to own a car - equal to one third of the annual total incomeof a middle-class family - and several thousand EUR more for fuel, insurance
and regular maintenance. As an alternative, car-sharing is more economical
than car ownership but not so convenient, because it is possible that two or
three families need to use that car at the same time. If people do not own a car,they will spend only (48 x 2 + 18 x 2) x 12 = 1,584 EUR a year on the public
transport - a considerable expense-saving option that one must think about.
After all, having no car is obviously the best choice and most of the Vauban
householders have decided to change their past lifestyle of their own accord,from driving cars into using public transport means, cycling and walking.

3. BACK TO HANOI: WHY NOT CAR AND MOTORBIKE-FREE?
Since August 2008 Hanoi has become a mega-city in Asia in terms of both area
(3,340 km2) and population (6.7 million inhabitants as of 2012), according to theGeneral Statistic Office. The inner city is extremely populous, 12,000 inhabitants
per km2 on average and 36,000 as the highest (Vietnams Press Agency, 2009).
The number of cars has kept on increasing very fast over the past ten years while
the urban infrastructure has not been properly upgraded. The road systems in
Hanoi fail to support the huge number of private motorized vehicles: 370,000 carsand 3.7 million motorbikes (Vietnams Law Newspaper, 2013). As a consequence,traffic congestions occur frequently throughout the city, not only in rush hours,
causing a lot of damage to the socio-economic development which cannot beeasily estimated or exactly calculated. Hanoi’s chaotic traffic situation is reported
to frighten foreign tourists, even those who have come back here many times.
This also accounts for the fact that Hanoi has never been ranked among the mostlivable cities in Asia and the capital city’s development goals towards 2030 could
hardly be achieved, unless a radical and comprehensive action is taken.

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Figure 2: Traffic congestions in the early morning and in the late afternoon in Hanoi

Figure 3: 101 reasons for traffic jams in Hanoi: heavy rain and road reconstruction

Figure 4: Hanoi old street night market - an example of a pedestrian zone,
but only at weekends, and the surrounding streets become parking areas
On a smaller scale, within a living quarter, many households have problems withparking. Only a few families have a garage (mostly for one car only) or sufficientplaces for two to three (or more) motorbikes. The others have to park their cars
several kilometers away and walk home. Part of the sidewalk or the public
courtyard, even the children’s playground, is occupied by day for parking purpose,
because at home there is no room for motorbikes. Only at night are motorbikes
kept indoors - often in the living room - which is of course troublesome. At
certain times of the day, the traffic flow within the living quarter is heavy. Mixed
together, motorized vehicles are likely to collide with one another or withbicyclists as well as with pedestrians.
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To solve the problems, the city authority in collaboration with the department ofurban planning and building tried to prevent accidents, regulate the traffic flows
and reduce the traffic jams by broadening the roads and streets, building more
footbridges or underground passages, adjusting work time between state-state andstate-private organizations and rejecting new registration for cars and motorbikes,
etc. But all these measures proved to be short-term or provisional actions andtherefore may not be able to deal with the problems to the root.
Back to the success story of Vauban neighborhood, both solutions have alreadybeen considered and partially applied to Hanoi over the last few years, but they
are not so well implemented in reality. For example: Bus is one of only two public
transport options in Hanoi. Compared to taxi, the bus service is much cheaper:
only 5,000 VND for a single trip in any direction within the city, while 12,000 to
15,000 VND per kilometer is charged for a taxi ride, the current exchange rate: 1
USD = 21,000 VND (VietcomBank, 2013). For this reason, bus still remains as apopular choice for low-income people and as a favorite transport means for many
students, despite the substandard service quality. Another problem is that the bus
system has not yet been well planned. In some places there is no (or almost no)bus service while the concentration of five or six bus lines in other parts of thecapital city has resulted in traffic jams. The bus is expected to serve a greaternumber of users in the future and supposed to improve the traffic situation.
Generally, social facilities and everyday life services are not very well organizedin Hanoi: either locally available and cheap but poor in quality and polluting or
good/high quality, environmental-friendly but not convenient in use and far from
home, as seen in the following circumstance: A typical woman working in a state
office brought home many things for dinner after work. Shortly before cooking,she realized that she had forgotten to buy some salad onions. Some street vendors
passing by or the green groceries near her home offered her the salad onions at areasonable price but she felt uncertain of the quality, because those salad onions
might contain preservatives at a higher level than the same category found in the
supermarket which went through a strict quality control. The supermarket was,nevertheless, two kilometers away - too far for her to walk after a long and hardworking day. In order to buy some fresh salad onions (only 3,000 VND a bunch),
she had to pay 5,000 VND for one motorbike parking lot within 20 minutes andhad to wait another 20 minutes just to take her motorbike out of the garage, which
was full at the time - during the day’s peak shopping hour.
The inhabitants have had to accept this inconvenience for years, as there has notbeen any other car parking concept ever proposed than the conventional model
mixed zone. The people will, however, move out as soon as they have enoughspending power to purchase new houses in another ward where the living
conditions and car parking services satisfy their high demand: economical,
convenient and safe. A car-free settlement is regarded as a preeminent concept todeal with the current traffic problems. But architects and city planners need toponder upon the question what makes it work. Otherwise, a car-free living quarter
will turn out to be another castles-in-the-air story, just like an eco-house before
which sounded very nice at first but nobody could afford at last.

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4. HOW DOES THIS NEW CONCEPT WORK?
In phase one, a car-free settlement in Hanoi will provide its inhabitants with ahigh-quality parking service: not only accessible 24/24 for car owners but also
going towards a greener and cleaner urban environment and reaching a more andmore comfortable living standard. In this in-depth view, a parking system in one
residential area should not be put inside (but next to) the housing blocks.
The other factors should also be taken into consideration. Street houses are highly
lucrative in a profit-oriented open market economy. The crucial point of the newliving concept to be proposed is that although the two main functions “residence”
and “business/service” are separated from each other, so that they will not affecteach other so much, they can be combined together - in one building as well as in
one block - to ensure a close and/or direct connection. Based on this symbiotic
relation, a typical settlement in Hanoi for the future will consist of two zones:


Periphery: is reserved for non-pollutant general service buildings such as
supermarkets, offices, stores or shop houses (large and medium-size) andkiosks (small). Car and motorbike parking houses can also be constructed
here. The residents and their guests drive into the garages from the streets,then exit the garages through the doors at the back and walk home.



Core: is planned for residence with various housing forms such as villas,
row-houses, low-rise and high-rise apartments divided into groups, open
for pedestrians and bicyclists only, with a small open space in the center of
each group of houses and a public place with public buildings and a large
open space in the heart of the whole living quarter.

Between the periphery and the core, there is a demarcation line called green line,
marking the end of the car zone and the start of the pedestrian zone to the central
point of the living quarter. But the fire safety requires an inner ring road for fireengines. In another emergency case - strokes at home and cardiovascular diseases
among old people - ambulance cars must approach all the houses or apartmentbuildings. Similarly, if a family moves to another district or buys new furniture, itneeds a cargo van that stops at the front door. Normally, the entrance ways end
with iron pillars or concrete posts that prevent motorized vehicles from entering
the pedestrian zone. If necessary, these posts can be operated to slide up and down
the holes and kept underground until the transport cars go out.
According to this spatial organization and functional separation, all the motorized
vehicles are kept in public parking garages that are optimally planned along theperiphery, taking into account:

the distance between two garages as well as between garages and homes toensure the radius of service and accessibility
the parking capacity of each garage to accommodate all the vehicles of theresidents and their visitors. Underground garages can be built if necessary.

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October
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2010)

Figure 6: Cross section of a car and motorbike-free living quarter in Hanoi(Nguyen, 2010)108

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The car parking service radius may vary between 250 and 300 meters based on theexperiences from other countries in the South East Asia region and the world. At
this distance, the residents do not hesitate to walk between homes and parking lots,
because it only takes them less than ten minutes to do so. At the moment, theconvenience while using parking services is what people concern the most. Thatmeans, aside from paying a reasonable monthly parking fee, people can drive inor out any time they need: 24 hours a day and seven days a week.
In phase two, when the time is right, the number of cars and motorbikes within theliving quarter will decrease step by step through a very high car parking fee which
would make people eventually sell and/or rent their cars as implemented in
Vauban (Freiburg, Germany). Functionally, in view of adaptive use, an old empty
garage could be turned into another public building for the local community, forexample a fitness center, a restaurant or probably an office for rent.
The periphery-and-core structure described above complies with the guiding
principle “simple but effective” and can demonstrate well the main functions thatit should perform: trading and parking (periphery) and living (core). In addition,
the periphery made up of two to three-storey non-residential buildings can help
protect the living space in the core from the negative influences (exhaust gas andnoise) of the surrounding streets. Then all the shop houses in the periphery will
only be used for commercial purposes. Nevertheless, shop-owners could have a
mid-day rest upstairs if they want, and leave their shops at the end of the day forhomes just one or two rows behind, and it will take them just a few minutes to go
back and forth between homes and workplaces.
At the same time, in order to promote the use of urban public transport with bus
and tram as two main options in Hanoi, the current systems should be redeveloped
into a city-wide network in line with the enhancement of the service quality. Eachsettlement has direct access to at least one bus or tram line, with at least one bus
stop or tram station every 400 meters along the road which enables local residents
to walk to the nearest station within 10 minutes from home. When half of the city
population uses public transport means on a daily basis instead of private vehicles,
they will not worry any more about getting stuck hours in traffic congestions.
5. HOW LARGE A CAR-FREE LIVING QUARTER SHOULD BE?
Based on the 400-meter distance between two next bus stops and with reference tothe right location of a bus stop, for example 100 meters from the crossroads, urban
planners can also limit the size of a typical living quarter for easy access, troublefree traffic circulation and effective management. It should not exceed 36 hectares(in form of a 600 m x 600 m square), quite suitable in terms of area and applicable
to most of living quarters in Hanoi at present (30 - 40 hectares). In case of a larger
area, mostly in the suburbs, the living quarter may be divided with one or two
sub-regional streets or lanes into two or three neighborhoods, about 30 hectares
each.

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6. A SURVEY FOR CAR PARKING CAPACITY AS A PRE-REQUISITECONDITION AND PUBLIC PARTICIPATION AS A CRUCIAL FACTOR
For a new urban housing project, before the planning stage begins, the planningteam should calculate the parking capacity, based on the following information:

the number of motorized vehicles within the area at present
the quantitative increase of private transport means in the future
how often a household welcomes guests and what kind of vehicle(s) theyusually drive to come and visit the family. These cars and motorbikes must
be of course added to the local parking capacity.

Without this information as important input data, the parking lots would be either
insufficient or surplus. In form of a questionnaire handed out to the householders
invited to attend a pre-planning conference, the information can be obtained whenpeople have filled in all the sections in the survey sheets and sent them back at
once or a few days later to the professional organization. Each citizen must be
responsible for the future development of his or her own living quarter by
providing accurate and complete information. The experts will analyze all theinformation and propose several development scenarios for the living quarter,
thereby helping the local people put their wishes for a safer and more sustainableliving environment into practice. In a more complicated case - a reconstruction
project - a thorough investigation should be conducted in the same way. Local
people know what they really need better than anybody else and have always
played a decisive role in the success of any urban development program, as also
clearly reflected in the second phase of the project, when they can collaborate
with the local authority to manage the project after it has been brought into action,according to the bottom-up co-management concept.
7. CONCLUSIONS
There is a fact in Vietnam and in Hanoi that new and breakthrough ideas are notoften accepted at the beginning, no matter how good these ideas may be or how
much they can contribute to the socio-economic development, because they lookvery different from what people used to see or imagine and require a significant
change in the long-time behavior and customs of the society. In this context, carfree settlement seems to be a tough nut to crack, but this nut keeps in it a truly finesprout that promises to grow for green. For various reasons, the sprout in the nut
has not taken root yet.
A living quarter organized in the periphery-and-core structure will be able to solve
the traffic and parking problems that most of the conventional living quarters arecoping with. The biggest difficulties while developing this concept will arise insocial aspects, such as the awareness and participation of the public together withthe cooperation between people and their representatives for a common purpose,etc., rather than in planning and design or in technical solutions. Therefore, inorder to make car-free living happen, it is important to start with thinking before
acting, but one should not think too long, because time and tide wait for no man.

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REFERENCES
Nguyen Q. M., 2010. A concept for ecological planning and building applied toresidential areas in Hanoi with Phung Khoang new town as a case study, PhD
dissertation, Bauhaus University Weimar, Germany, p. 93
Rosenthal E. and Sprecht M., 2009. In German suburbs life goes on without cars,
The New York Times, published on May 11, 2009. Electronic version retrievable
at: http://www.nytimes.com/2009/05/12/science/earth/12suburb.html?_r=0
Freiburg City Council and Vauban Project Management Board, 2008
Vauban Official Website www.vauban.de/infoVietcomBank exchange rate on August 24, 2013 www.vietcombank.com.vn
General Statistic Office (GSO), 2011. Population and population density in Hanoi
and other cities and provinces in Vietnam, Report retrievable on-line at
http://www.gso.gov.vn/default.aspx?tabid=387&idmid=3&ItemID=12875
Vietnams Press Agency, 2009. The most populous districts in Hanoi. Electronic
version retrievable at http://www.baomoi.com/Quan-Dong-Da-co-mat-do-dan-socao-nhat-Ha-Noi/121/3286889.epi
Vietnams Law Newspaper, 2013. Over 90% of cars in Hanoi are parking inwrong places. Published on June 8, 2013. Electronic version retrievable at
http://www.phapluatvn.vn/xa-hoi/doi-song/201306/Hon-90-xe-o-to-o-Ha-Noidang-do-sai-quy-dinh-2078921/
Hoang H., 2009. Hanoi old street night market becomes busier at the end of theyear.
http://vnexpress.net/tin-tuc/xa-hoi/nhon-nhip-cho-dem-pho-co-dip-cuoinam-2150967.html
Official traffic information and education websites: www.vovgiaothong.vn,
www.luatgiaothong.vn, www.duongbo.vn

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Land use of super levees along the Arakawa
River in the low-lying areas of Tokyo
Hitoshi NAKAMURAI1 and Takaaki KATO2
Professor, Shibaura Institute of Technology, Japan
nakamu-h@shibaura-it.ac.jp
2
Associate professor, ICUS, IIS, The University of Tokyo, Japan
1

ABSTRACTA super levee is a river embankment with a broad width which can withstand evenif overflow. Because a super levee project is often promoted in conjunction withthe urban development project along the river, the creation zone will exist
discontinuously in the long time. After the super levee project was judged to be"abolishment" by the national budget screening system in 2010, Ministry of Land,
Infrastructure and Transport reviewed its policy drastically in August 2011.
According to this new policy, the creation zone of super levees is narrowed down
to the low-lying area or densely built-up area in the large city where serious
human damage is likelier to occur in the large-scale flood. Especially in the lowlying area, it is necessary to create the space that inhabitants can evacuate safely
in the large-scale flood. In this view, each super levee can be also utilized as alarge-scale upland evacuation area by creating parks and other public facilities
on the site. This paper examined the actual land use of super levees in the lower
reaches of the Arakawa River in Tokyo and considered the possibilities andproblems of promoting a super levee project. Along the Arakawa River, superlevee projects have been complete or in progress at 15 sites. As for the land use of
these 15 super levees, 8 projects include dwelling houses, 4 projects include
public parks, 8 projects include public facilities other than park and 2 projects
include others such as commercial buildings. From the standpoint of securing an
upland evacuation area, it is desirable to create a public park or public open
space on the site, but these cases are only 4 in 15. However, under the certain
conditions, it is possible to use public facilities, roads, private open spaces,
commercial buildings and high-rise dwelling houses on the super levee as anevacuation area.
Keywords: super levee, land use, flood, evacuation area, low-lying area
1. INTRODUCTION
1.1 Super Levee
A super levee is a high standard river embankment with a broad width which canwithstand even if overflow (Stalenberg B. and Kikumori Y., 2008). It is about 30
times as wide (about 200 m to 300 m) as it is high, so that even if it is overtopped,113

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surface (Figure 1, Arakawa-Karyu River Office, 2013).
A previous conventional dike can be transformed into a super levee byheightening of the top and by broadening of the slope. The ownership of the landon the super levee special development zone remains unchanged after the project.
This special zone can be used for urban land use.
In comparison with the conventional dike, Figure 1 shows various advantages of asuper levee such as ground improvement, open space as an evacuation area, gentle
slope and easier access to the river, better landscape and living environment.

Figure 1: Super levee (Arakawa-Karyu River Office, 2013)
1.2 Super Levee project
A high standard levee improvement project (a super levee project) started in 1987
along the six large rivers in Tokyo and Osaka, i.e., Tonegawa, Edogawa, Arakawa,
Tamagawa, Yodogawa and Yamatogawa.
Because a super levee project is often promoted in conjunction with the urban
development project along the river, the creation zone will exist discontinuously
in the long time. According to the report of the Board of Audit of 2011, as of theend of March 2010, a total length of the districts which enforced projects was 50.6
km (123 districts) and its implementation rate was 5.8 % of a total length of the
project zone (872.6 km). As for the project priority zone (223.8 km), a total lengthof the districts which enforced projects was 27.7 km (59 districts) and its
implementation rate was 12.4 %.
By the national budget screening system of 2010, the total project expense of thehigh standard levee for the past 24 years was estimated for 694 billion yen. In
other words when projects are promoted at the same pace, approximately 400
years are necessary before a total project zone is completed, and 12 trillion yen isrequired for overall project costs. Therefore, in the budget screening, the superlevee project was judged with "abolishment."
1.3 Low-lying area
After the judgment by the budget screening in 2010, Ministry of Land,
Infrastructure and Transport (MLIT) reviewed its policy drastically in August
2011. According to this new policy, the creation zone of super levees is narrowed

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down to the low-lying area or densely built-up area in the large city where serious
human damage is likelier to occur in the large-scale flood.
According to MLIT, population in the low-lying areas (the area that the ground islower than a mean sea level) in three major metropolitan areas, i.e., Tokyo, Osakaand Nagoya in Japan, is said to be more than four million in total. These low-lying
areas have been exposed to flood risks and the risks have been increasing due toclimate change.
However, recently, few floods have occurred in these areas because of theenhancement of flood control which is sustained mostly by the structural
measures. As a result, the awareness of flood risk has been declining and the
preparation for the large-scale flood is insufficient for local people in the lowlying areas.
These areas have another flood risk caused by the earthquake. The probability of
the conjunction of an earthquake and an extreme weather causing flood may be
negligible. However, the possibility of having flood for the restoring term of flood
control facilities such as levees damaged by the earthquake cannot be ignored
because the recovery of the facilities will take much time.
1.4 Flood hazard map
The revision of flood prevention law in 2005 has obligated municipalities topublish a flood hazard map which has information about the flood hazard andevacuation areas. However, municipalities in the low-lying areas are facing thedifficulty to make a reasonable hazard map for citizens because there are notsufficient safe evacuation areas in case of the large-scale flood.
For example, Katsushika ward in the eastern part of Tokyo have no choice but toguide more than 27 thousand people to upland evacuation areas with the distancemore than 10 km. In reality, these evacuations will be difficult under the present
conditions. And it is estimated that several tens of thousands people cannot
evacuate even if all tall buildings including the private buildings are assumed tobe evacuation places.
Therefore, especially in the low-lying area, it is necessary to create the space that
inhabitants can evacuate safely in the large-scale flood. In this view, each superlevee can be also utilized as a large-scale upland evacuation area by creating parksand other public facilities on the site.
1.5 City planning master plan
Examining the description of the city planning master plan of the local
governments (5 wards; Sumida, Koto, Adachi, Katsushika, Edogawa) along the
Arakawa River in the lowland of eastern Tokyo, every local government specifies
the necessity of the flood control measures.
Although super levee project zones are specified in the whole lower reaches of the
Arakawa River, they are not specified in the map of the city planning master planof each ward. Exceptionally, in the Katsushika city master plan (Figure 2), only
the generous position of “the evacuation area by the creation of the upland” isshown in a figure of the safety urban development policy (flooding). Some areas
along the Arakawa River are designated as the planned upland evacuation area.
However, there are no urban planning regulations about super levees.

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Katsushika city master plan (Adapted from Katsushika ward, 2012)
1.6 Purpose
The purpose of this study is to examine the actual land use of super levees in thelower reaches of the Arakawa River in Tokyo and to consider the possibilities andproblems of promoting a super levee project.
2. SUPER LEVEES ALONG THE ARAKAWA RIVER
2.1 Super levees along the lower reaches of the Arakawa River
From an interview survey to the Arakawa-Karyu River Office in January 2013, inthe lower reaches of the Arakawa River, super levee projects have been complete
or in progress at 15 sites, 8.75 km as of March 2012 (Figure 3, Table1).
Completed projects are 13 sites, approximately 5.03 km, and projects in progressare 2 sites, approximately 3.72 km. It accounts for about 15 % in a total length of
58.2 km.
It is pointed out that the difficulty of consensus building, the prolongation of the
project, the large scale compensation for removal, influences to the surroundings
including the sunshine condition are the main disincentive of the project.

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Figure 3: Super levees along the lower reaches of the Arakawa River(Adapted from Arakawa-Karyu River Office, 2007)

Table 1: Super levees along the lower reaches of the Arakawa River
Super levee
district

Main land use
Length Area
PublicDwelling Public(ha)facility other Ohters (m)
house
park
than park

1

Shinsuna

2

Komatsugawa

X

3

Hirai

X

4

Hirai 7-chome

X

5

Senju

X

6

Odai

X

7

Odai 1-chomeX

8

Miyagi9

Shinden10

Shikahama

11

Kawaguchi

12

Kita-akabane

13

Ukima

14

Funado15

Toda-koen

X

X

1,140

18

158

2004

X

2,380

23

97

in progress

100

1.5

150

2003

100

1

100

2000

100

0.4

40

1991

670

12

179

2004

300

1.6

53

2001

1,360

27

199

2007

300

10

333

1991

1,340

11.5

86

in progress

500

4.2

84

2003

X
X

X

X
X

X
X

X

FillingMeanwidth completion
year
(m)

X
X

X

provisional completion
X
X

70

0.6

86

2006

150

2.8

187

2008

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Table 2: Public facilities and others on the super leveeDistrict1

Shinsuna

Public facilities other than park + Others
Water station, Water treatment plant, Electric power transmission facility

2 Komatsugawa

Junior high school, Pumping station

5

Community (Lifelong learning) center

Senju

7 Odai 1-chome

New transportation system station, Station square + Commercial buildings

9

ShindenElementary school, Junior high school, Sewerage facility, Fire fighting center

11

Kawaguchi

Elementary school, Junior high school, Kindergarten + Temple, Driving school

12 Kita-akabane

Disaster prevention station (stockpile warehouse for food and materials)

14

Recycling facility

Funado

2.2 Scale of super levees
The scale of these super levees varies. As for the length of these 14 super levees
excluding Ukima district which is regarded as the provisional completion, 5
projects are less than 200 m. 4 projects are more than 200 m and less than 1,000 m.
4 projects are more than 1,000 m.
As for the area of 14 super levees, 6 projects are less than 2 ha. 2 projects are
more than 2 ha and less than 5 ha. 6 projects are more than 10 ha.
As for the mean width, 6 projects are less than 100 m. 7 projects are more than
100 m and less than 200 m. According to the concept of a super levee, it should beconstructed with about 200 m to 300 m width. However, only one project is morethan 200 m.
3. LAND USE OF SUPER LEVEESAs for the land use of these 14 super levees (Table 1), 8 projects include dwellinghouses, 4 projects include public parks, 8 projects include public facilities otherthan park and 2 projects include other land use such as commercial buildings.
Public facilities other than park and other land use are shown in Table 2.
The land use of super levees can be roughly classified into 4 types: a dwellinghouse type, a public park type, a public facility type other than a public park typeand a mixed-use type.
3.1 Dwelling house typeA dwelling house type can be further classified into a detached house residential
area type, a single high rise apartment type, a mixed-use type including theaggregation of high rise apartments.
Hirai 7-chome district corresponds to a detached house residential area type. Hirai,
Senju and Odai district correspond to a single high rise apartment type. But in the
Senju district, there is a public facility in the lower story of the apartment.
Komatsugawa, Odai 1-chome, Shinden and Kawaguchi district correspond to amixed-use type including the aggregation of high rise apartments.

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Hirai 7-chome district

Odai District

Shinden district

Figure 4: Dwelling house type
3.2 Public park type
A public park type can be further classified into a single park type and a mixeduse type including a park.
Miyagi, Shikahama and Toda-koen district correspond to a type that is used only
as a public park. In particular, Shikahama district is used for an agricultural park.
Komatsugawa district corresponds to a mixed-use type including a large
evacuation park.

Miyagi District

Shikahama District

Komatsugawa district

Figure 5: Public park type
3.3 Public facility type
A public facility type other than a public park type can be further classified into asingle use type with the public facility and a mixed-use type including the public
facility.
Shisuna, Kita-akabane and Funado district correspond to a single use type withthe public facility. Komatsugawa, Senju, Odai 1-chome, Shinden and Kawaguchi
district correspond to a mixed-use type including the public facility.

Kita-akabane district

Funado District

Kawaguchi district

Figure 6: Public facility typeLand use of superleveesalong levees
the Arakawa
Riverin the River
low-lyingareasof TokyoLand useof superalong theArakawain thelow-lyingareas of Tokyo

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3.4 Mixed-use type
As has already been pointed out, 5 districts (Komatsugawa, Senju, Odai 1-chome,
Shinden, Kawaguchi) correspond to a mixed-use type. 4 districts except the Senju
district are relatively equivalent to a large-scale super levee.

Komatsugawa district

Odai 1-chome district

Shinden District

Figure 7: Mixed-use type
4. CONCUSION
From the standpoint of securing an upland evacuation area, it is desirable to createa public park or public open space on the site, but these cases are only 4 in 15.
However, under the specific conditions, it seems to be possible to use public
facilities, roads, private open spaces, commercial buildings and high-riseapartments on the super levee site as small-scale distributed evacuation spaces.
From this viewpoint, it is important to reevaluate the need of super levees as theupland evacuation area in the large-scale flood in the low-lying area.
A detailed analysis of possible evacuation spaces on the super levee andevacuation routes to them is the next research theme. And an appropriate costbenefit analysis of the super levee as the upland evacuation area should be further
considered.
REFERENCES
Arakawa-Karyu River Office, 2007. Super Levees Guidebook. Ministry of Land,
Infrastructure and Transport, Tokyo, Japan.
Arakawa-Karyu River Office, 2013. Activities of our Office: Super Levees.
http://www.ktr.mlit.go.jp/arage/english/outline/01.html#1 (accessed 1 July 2013).
Katsushika ward, 2012. Katsushika city master plan. Tokyo, Japan.
Stalenberg B. and Kikumori Y., 2008. Urban Flood Control on the Rivers ofTokyo Metropolitan. In Graaf, R. D. and Hooimeijer, F. (editors), Urban Water inJapan, Taylor & Francis Group, London, UK, 119-141.

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Anomaly detection of seasonal andannual environment changes of the world
Haruo SAWADA
Project Professor, ICUS, IIS, The University of Tokyo, Japan
sawada@iis.u-tokyo.ac.jp
ABSTRACTThis report shows how remote sensing data are used for global environment
health monitoring and development of a new processing methodology for anomaly
detection. Seasonal changes in a year are common phenomena in the world
although they show different severity to human beings. These phenomena
continued for a long time and they characterized natural vegetation and humanbeings whose lives are supported by local ecosystems and global environment.
Global environment changes affect the ecosystem services through the changes ofvegetation health. Cloud free 10 day composite images of MODIS and
SPOT/Vegetation satellite data clearly show not only the seasonal changes ofnatural environmental parameters but also the anomaly of seasonal changes ofEarth surface, which can be used as the influence of environment changes toecosystem, services.
Keywords: environment health, remote sensing, seasonal change
1. INTRODUCTION
Phenological changes of ecosystem are closely related to the changes of naturalenvironment, such as water, temperature, soil and solar radiation. Even tropicalforests show seasonal variations in the presence of new leaves, flowers, and fruits
The National Oceanic and Atmosphere Administration (NOAA) reported thatwarm temperature trends continue near Earth’s surface and datasets of NOAAshow 2012 was among the 10 warmest years on record (Blunden and Arndt, 2013).
This report also explained that the United States and Argentina had their warmest
year on record. Many of the events that made 2012 such an interesting year arepart of the long-term trends we see in a changing and varying climate - carbon
levels are climbing, sea levels are rising, Arctic sea ice is melting, and our planet
as a whole is becoming a warmer place.
Rising temperatures add energy to the atmosphere, and computer models warnthat this will produce wider and wilder swings in temperature and rainfall andalter prevailing wind patterns. Therefore, global warming will likely increase thenumber and severity of extreme weather events. These phenomena continued for along time and they characterized natural vegetation and human beings whose lives
are supported by local ecosystems and global environment. We call these supportsof ecosystem as “ecosystem services”. For example, carbon sequestration, climate
regulation and purification of water are considered ones of regulating services.

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Mitigation of disasters (ex. flood and drought) is one of preserving services.
Global environment changes affect these ecosystem services through the changesof vegetation health. This report shows methodologies for monitoring the trendsof long-term influence of Earth environment to ecosystems and for detecting
anomaly events on land surface by global observation satellite sensors.
2. SATELLITE ENIVIRONMENT INDICES
Since the 1980s, NOAA’s Polar Orbiting Environmental Satellite have provided
daily global coverage of multi-spectral observations of visible and near-infraredsurface reflection as well as surface temperature radiation. The TERRA satellite’s
MODIS (MODerate resolution Imaging Spectrometer) data with advanced
resolutions in both spatial and spectral characteristics have been provided in daily
base since 2000. From these satellite data, some indices related to vegetation
condition, such as the Normalized Difference Vegetation Index (NDVI) (Justice etal.. 1985) and the Leaf Water Content Index (LWCI) (Anazawa et al. 2001) , canbe derived. The NDVI exploits the spectral properties of green vegetation and the
LWCI shows the water contents of plant leaves, which are related to thephotosynthesis process in leaves. The data, however, are often affected by various
atmospheric disturbances (aerosol, water vapor and ozone), cloud cover, solar
illumination. Instrument degradation, insufficient calibration and satellite orbit
drifts as well as the different characteristics of sensor systems even on the same
satellite series. Therefore, appropriate preprocessing to observed data is required
to monitor ecosystems for a long period of time with the same quality.
Global NDVI data have been used to clarify trends of seasonal changes ofvegetated areas. Myneri et al (1997) investigated the 1981-1991 Advanced VeryHigh Resolution Radiometer (AVHRR) NDVI for northern hemisphere anddetected the trends of advance in active growing season of 8±3 days and delay inthe declining phase of 4±2 days over this decade. It is an example of processing
to detect the trends of seasonal changes of vegetated area in global scale. However,in order to address the issues arising due to the various environmental problems
that are currently attracting attention, it is necessary to devise a method thatenables monitoring of fluctuations of vegetation conditions such as moisture,temperature and land cover changes.
3. METHODS
Various research projects on global environment utilize the characteristics of thecyclic nature of multi-temporal satellite data. In those research projects, the n-day
composite imagery (ex. n=8, 10), which is created by selecting the best data in 8
or 10 days for every pixel, is often used for characterizing seasonal changes.
However, the influence of clouds and haze remain even in these 8 or 10-day
composite data and this makes the phenology monitoring with 10-day interval
complicate (Sawada et al., 2005). Monthly composite data, however, are notappropriate to monitor phenology dynamics because the seasonal changes ofvegetation are phenomena taking place in a few weeks for most of cases. Then we

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developed a novel method for time series modeling and spectrum anomaly
detection applicable to SPOT/vegetation and MODIS as well as AVHRR data.
Since this methodology can extract a seasonal change model for each pixel
separately, it is useful to monitor land-cover change and ecological disasters.
3.1 Generation of spectral codebook and encoding
The batch-learning self-organizing map (SOM) algorithm was introduced in orderto generate a spectral codebook which encodes multispectral data. In each pixel,"pure components" (end-members) are extracted throughout the data collection
period by the orthogonal projection analysis (OPA) (Cuesta Sanchez et al., 1996)
for removing influence of cloud, haze and other noise for observing earth surface.
“Pure components” are derived by the batch-learning SOM algorithm. Generated
SOM is used as a codebook in the spectral encoding step. In addition, SOM nodes
which are assigned as cloud and haze are masked out. Then, multi-temporal andmulti-spectral data, such as MODIS data (MOD09A1) and SPOT/VEGETATION(S10) products, are encoded by the nearest-neighbor method. We set the SOM
map as 20 x 20 (the total number of codes is 401 including the “NULL” code).
3.2 Generation of spectral codebook and encoding
The observation data vector and the state vector at (x,y) pixel are denoted byo(x,y) and q(x,y), respectively. Assuming that q(x,y) follows Markov process, we
get the conditional probability of q(x,y) (Rabiner, 1989).
3.3 Classification of seasonal change profile
Since the element of the state vector q(x,y) is a nominal scale value, we developed
a nominal scale vector (and/or strings data) classification method. Firstly,D(q(x,y)) is defined as a characteristic matrix of the state vector q(x,y). The (i,j)
element of D(q(x,y)) is equal one when qj(x,y)= i and otherwise zero. The size ofthe matrix D(q(x,y)) is N x T. In bioinformatics researches, D is called ‘Position
Specific Scoring Matrix’. Next, the centroid of D, qcent (Q), is defined when Q is a
set that consists of state vectors. And we define fij(X) as a function that returns(i,j) element of a matrix X for further convenience. Similarity of Q and anotherstate vector q’ is also defined by a formula.
3.4 Spectral anomaly detection
In general, an anomaly detection methodology is required to clearly distinguishspectral anomaly (i.e. land cover changes) and phenological changes. If theseasonal change profile of the reference year q(x,y) and clustering results Q are
known, we can define observation probability of encoded spectrum p(vt (x,y)) in
another scene t(time) at (x,y) pixel. For setting threshold value to identify anomaly,
we assume that encoded spectra are generated by random process. Then, theanomaly score of each pixel is compared with the threshold of the anomaly.

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4. RESULTS AND DISCUSSION
4.1 Water coverage monitoring
An example of our processing on MODIS (MOD09A1) data is shown in Figure 1.
414 scenes from the early January 2001 until the end of December 2009 wereused. The target area is Amazon River basin (10N-20S, 80W-40W). Figure 1a, 1b
and 1c are raw composite, time-series modeling results (by HMM) and cluster
centroid, respectively. Almost all the influences of cloud and noises are cleaned
up. 23 states were obtained and “state 23” is assigned to water spectra which isclearly distinguished from other states in the spectral shape. Then the water
coverage period map was obtained from the occurrences of “state 23”.

Figure 1 Examples of discrete time-series processed MOD09A1 data (Jan. 122009) (a) original MODIS (b) HMM processed (c) cluster centroid image
5.2 Burned area detection
In order to detect burned areas with 10 day interval, the SPOT/vegetation-S10
products were processed. The target area was far-east Russia (50N-54N, 127E133E). The data collection period as the reference year was from Apr. 1999 toMar. 2000 (one year, 36scenes). We set the SOM node size to 10 x 10 forclustering of seasonal change profile. As the result, 15 states were obtained andthere were mainly four categories, namely “vegetation”, “soil”, “snow” and“water”. The data collection period for anomaly detection was from Jun. to Aug.
2000 (12scenes). For comparison, the products of the same area of the GBA2000(Global Burned Area, Grégoire et al., 2006) is shown in Figure 2. The comparison
shows that our method was effective to identify burned area with pixel bases.
5.3 Forest development area detection
The 10-days composite MODIS data were processed. MODIS data were obtained
from Web-MODIS system (Takeuchi et al., 2005). The result shows that it
identifies deforestation trends by pixel bases (Figure 3, 13.417N, 106.112E).
ASTER VNIR images with 30 m resolution are also used for checking the result.
6. CONCLUSIONS
We developed a discrete time-series model using a self-organizing map (SOM)
and a hidden Markov Model (HMM) to reduce the influence of clouds in order toimprove the quality of the products. The products can clearly distinguish spectral

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anomaly and phenological changes. Our method was effective to identify land
cover changes (i.e. forest fire and deforestation) with pixel by pixel, but further
study will be required to clarify its limitation on usage for land cover change
detection. A small land cover changes will not be identified.
ACKNOWLEDGEMENT
This research used ASTER data beta processed by the AIST GEO Grid from
ASTER data owned by the Ministry of Economy, Trade and Industry. This study
was partially supported by JST
REFERENCES
Anazawa, M., G. Saito, Y. Sawada, and H. Sawada, “Vegetation monitoring study
using leaf water content index (LWCI) and NDVI” Processing 22nd Asian
Conference on Remote Sensing, vol. CD, pp. 1-6, 2001.
Blunden, J., and D. S. Arndt, Eds., 2013: State of the Climate in 2012. Bull. Amer.
Meteor. Soc., 94 (8), S1-S238.
Cuesta Sanchez, F., Toft, J., van den Bogaert, B. and Massart, D. L., 1996.
Orthogonal Projection Approach Applied to Peak Purity Assessment. Anal. Chem.,
68 (1), pp. 79-85.
Gregoire, J. M., Tansey, K. and Silva, J. M. N., 2003. The GBA2000 initiative:
developing a global burnt area database from SPOT-VEGETATION imagery. Int.
J. Remote Sens., 24(6), pp. 1369-1376.
Gribskov, M., McLachlan, A. D. and Eisenberg, D., 1987, Profile analysis:
detection of distantly related proteins. Proc. Natl. Acad. Sci. USA., 84(13), pp.
4355-4358.
Justice, C.O. J. R. G. Townshend, B. N. Holben, and C. J. Tucker, “Analysis of
the phenology of global vegetation using meteorological satellite data,”
International Journal of Remote Sensing, vol. 6, no. 8, pp. 1271-1318, 1985.
Kohonen, T., 2000. Self-Organizing Maps (2nd ed.). Springer, Berlin, chapter 3.
Mynenl,R.B., C. D. Keeling, C. J. Tucker, G. Asrar, and R. R. Nemanl, “Increased
plant growth in the northern high latitudes from 1981 to 1991,” Nature, vol. 386,
pp. 689-702, 1997.
Rabiner, L.R., 1989. A tutorial on hidden Markov models and selected
applications in speech recognition. Proc. of the IEEE, 77(2), pp. 257-286.
Sawada, Y and H. Sawada, “Development of a discrete time series model for
vegetation” International Archives of the Photogrammetry Remote Sensing andSpatial Information Science, vol. XXXVIII, no. 3, pp. 719-724, 2010.

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Sawada, Y., Mitsuzuka, N. and Sawada, H., 2005. Development of a time-seriesmodel filter for high revisit satellite data, Proceedings of the Second International
VEGETATION User Conference (Veroustraete, F., Bartholome, E. and
Verstraeten,W.W. ed.), pp. 83-89, Office for Official Publications of the European
Committees, Luxembourg.
Shannon, C., 1948. A Mathematical Theory of Communication. Bell Syst. Tech.
J., 27, pp. 379-423.
Takeuchi, W., Nemoto, T., Baruah, P. J. and Yasuoka, Y., 2005. Online satellite
data distribution system for the monitoring of environment and disaster over Asia
(in Japanese), Photogrammetry and Remote Sensing, 44(2), pp. 68-72.

Figure 2 Identification of burned area.
Figure 3 Deforestation detection and trend

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Analysis on urban fire hazard and risk zones
assessment mapping in Bangkok, Thailand
1

Praopanitnan CHAIYASANG1, Nitin Kumar TRIPATHI2
Remote Sensing and Geographic Information Systems, Thailand
praopanitnan@hotmail.com
2
Asian Institute of Technology, Thailand

ABSTRACT
Bangkok is the mega city with high vulnerability because of the urbanization.
Many people migrate to urban area because of job opportunity and economic
factors, while their quality of life is decreasing. High population density, low
quality of housing, and infrastructure shortages can lead to the risk. The problem
is they might not know that they are at risk. Therefore, risk identification and themitigation plan should be considered for coping mechanism. According to thedisaster statistics, fire hazard is the one of the main problems in Bangkok. Firehazards are increasing in Bangkok. It is such a problem which is becoming more
intensive. Therefore, Bangkok is also the risk area in case of urban fire hazard
because of the urbanization including population and building density, andhuman activities. Thus, GIS and urban planning knowledge can be used tosupport Bangkok’s abilities to cope with risk, to prevent or reduce the likelihoodof this kind of hazard which may result in death, injury, or property damage. The
risk zones can be both high density community and urban abandoned land. Mostof urban abandoned land in Bangkok is belonging to private sector, thus,
government cannot operate or improve this kind of land. Consequently, theprivate sector should realize that their areas are at risk, they have to manage andgive important by their own to avoid from the causes of urban fire. Certainly, cooperation between government, Department of Disaster Prevention and
Mitigation (DDPM), private sector, and people, will be required to cope withurban fire as a public hazard. Data about past events may help us to findgeospatial pattern/ frequency and hazard hotspots. There are vulnerable
communities and infrastructure. These are to be mapped and geodatabase need tobe created. These data can be used to develop the model for urban fire risk map
and help the urban fire risk management.
Keywords: Urban Fire Risk, Fire Hazard, Urbanization
1. INTRODUCTION
Urban fire is the public hazard which can happen anytime. It directly affected tohuman living such as human health, human property, economy damages, andenvironment. Urban fire hazard can be classified into two types. The first isnaturally occurring fire, for instant, dry leaves friction in the summer or dry
season. The other type is fire caused by human such as grass burning, forgetting
turn off the lights, and short circuit. There are many factors can lead to fire hazard

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related to the urban planning approach which controls urban structure.
Furthermore, it is necessary to integrate geographical technique to make clear inphysical perception. Thus, GIS is the one technique to measure the physicalfactors. It can be used to prevent the fire hazard and decrease the damages. It is
possible to identify the urban fire risk zones by using GIS. People can realize thevulnerable factors of their areas, these factors have to be considered for
preparation and prevention.
Bangkok faced fire hazard increased in every year. It's such a problem which is
becoming more intensive. Therefore, Bangkok is also the risk area in case ofurban fire hazard because of the urbanization including population and building
density, and human activities. Thus, GIS and urban planning knowledge can beused to support Bangkok’s abilities to cope with risk, to prevent or reduce thelikelihood of this kind of hazard which may result in death, injury, or property
damage. The risk zones can be both high density community and urban
abandoned land. Most of urban abandoned land is belonging to private sector,
government cannot operate or improve this kind of land. Thus, if the private
sector realizes that their areas are at risk, they might manage and give importantby their own to avoid from the causes of urban fire hazard. Moreover, cooperation between government, Department of disaster Prevention and Mitigation(DDPM), private sector, and people, will be required to cope with urban fire as apublic hazard.
2. STATEMENT OF PROBLEMS
Urban development in Thailand is likely to grow rapidly especially in Bangkok.
Since the industry has driven to be the main country's income, many labors
migrate from rural to urban because urban has high job opportunity. It can be thecause of slum which lack of efficiency infrastructure including fire system. Due tolacking of proper urban planning, urban problems have occurred; social,economic, environmental problem, and low quality of life with less standard
secure. The one of main problem is the fire risk. Overcrowding communities canbe causes of heat-related activities such as cooking, more power usage, and fuelstorage in household. Furthermore, fire system in Thailand is still inefficient suchas lack of fire mitigation equipment in some area and lack of coordination
between the agencies involved. Therefore, the damage will be very intense.
Urban fire hazard often happens in overcrowded communities with highpopulation density, industrial buildings, shopping centers and theaters where theseplaces often have high electric power usage. It can be lead to thermal energy
which is cause of fire hazard.
Due to fire risk factors, Bangkok is the one of risk area according to the fire
history statistic.

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Figure 1: Urban Fire Hazard in Bangkok 1990 - 2011
The development of economic in Thailand has been rapid in the last 20 years. It
can be seem from the building increasing especially in Bangkok which is the
economic center of Thailand. Bangkok is a modern high-rise building
construction increased steadily, particularly in the areas of business growth. Dueto the convenient location for the urban lifestyle, the high-rise building isincreasing every year. Thus, it is very important to consider structure of thebuilding, it has to be strong and safe follow the building control regulation andengineering standards. According to the disaster statistics, fire was occurred
greater than any other disaster. Fire hazard lead to the loss of life and property,
especially in a public housing, high-rise buildings, and large buildings. If thebuildings do not have the efficiency fire protection and extinguishing systems,
such cases will lead to injury, loss of life, and property that may be invaluable.
If fire occurs without fire prevention and efficiency system, it can lead to the highinjury, death, and property damages. Hence, the high building should set up thefire prevention system follow the law, they have to maintain the system to beavailable all the time. Government should realize about this risk and try to solve
this problem by using law. It can be used to control the building's owner to dofollow the law for more safety. The people who stay in the building have tounderstand about the fire prevention and mitigation as well. The a fire occurs,
they are capable enough to break the cycle of fire spread initially and they also
can help themselves or others to escape the danger of fire which is going in thebuilding.
Therefore, the fire risk assessment is the one tool which was created by
Department of disaster Prevention and Mitigation (DDPM). They would like toprovide this systematic tool for the local area for applying with the particular areaor the community. It can be used to identify, predict, and ranking the community’s
risk. This systematic tool also can help the local government for supporting theefficiency decision making of disaster risk reduction. As well as the geodatabasecan be used to develop policies, strategies and plans, projects. This is a truly
integrated work. The Department of Disaster Prevention and Mitigation can use
the geodatabase from the operation of a fire risk assessment to manage the fire
safety program and also apply it for the local scale.

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3. OBJECTIVES OF STUDY
The following objectives have been defined in the proposed system;
3.1
To analyze fire hazard status and physical condition in Bangkok
3.2
Mapping the urban fire risk zones of Bangkok
4. METHODOLOGYThis stage involves the collection and gathering of digital thematic maps andstatistical data of Bangkok, Thailand relevant to the study. The following thematic
layers are used in GIS analysis.
• Administrative Boundary• Land use• Source of water• Road Network (Accessibility)• Fire Station
4.1 Analytic Hierarchy Process (AHP)
AHP and Weighted Overlay Tool are necessary for this study, the pixel is also
important to calculate the weighting score. Thus, the covert feature to raster tool isshould be used in this step. The overlay method can only be implementing on
raster so that before implementation of the weighted overlay tool, it is necessary
to convert the vector data in to the raster by conversion tools (feature to raster).
Due to the result of AHP, it can be used to rank the importance level of fivecriteria.
Table 1: Analytic Hierarchy Process
Criteria
Land Use (F1)
Water Body (F2)Fire Station (F3)Road Surface (F4)Road Lane (F5)
Sum

Land
Use
1.000
0.5
3
0.33
0.5
3.33

Water
Body
2
1.000
3
0.33
0.5
6.85

Fire
Station
0.33
0.33
1.000
0.25
0.25
2.16

Road
Surface
3
3
4
1.000
2
13

Road
Lane
2
2
4
0.5
1.000
9.5

Table 2: Normalized Matrix
Criteria
Land Use (F1)
Water Body (F2)Fire Station (F3)Road Surface (F4)Road Lane (F5)

130

Sum
0.300
0.150
0.900
0.100
0.150

0.292
0.146
0.438
0.048
0.073

0.153
0.153
0.463
0.116
0.116

0.231
0.231
0.308
0.077
0.154

0.211
0.211
0.421
0.053
0.105
Sum

1.186
0.891
2.530
0.394
0.598
5.599

Priority
Vector
0.212
0.159
0.452
0.070
0.107
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Table 3: Estimating Consistency

F1
F2
F3
F4
F5

F1

F2

F3

F4

F5

1.000
0.5
3
0.33
0.5

2
1.000
3
0.33
0.5

0.33
0.33
1.000
0.25
0.25

3
3
4
1.000
2

2
2
4
0.5
1.000

Consis- Weight
tency
Sum
1.186
6.181
0.891
4.697
2.530
12.730
0.394
2.011
0.598
3.057

Consistency
Vector (λ)
5.212
5.272
5.032
5.104
5.112
5.146

Table 4: Inconsistency Indices (RI)
N
RI

1
0.00

2
0.00

3
0.58

Consistency Index (CI)=(5.146 – 5) / 4

Consistency Ratio (CR)

4
0.90

5
1.12

6
1.24

7
1.32

8
1.41

9
1.45

=

Consistency Vector (λ) – N
N -1=

0.0365==CI / RI
0.0365 / 1.12

=

10
1.49

0.0326

Consistency Ratio = 0.0326 (It is less than 0.1, thus, it is acceptable)
4.2 GIS Data Manipulation and Analysis
Factor Rating is required to classify the level of risk in each factor. There are fourlevels of risk in this study; highest risk, high Risk, moderate risk, and low risk.
Table 5: Risk Level and Its Description
Rating
4

Risk Level
Highest Risk Area

3

High Risk Area

2

Moderate Risk Area

1

Low Risk Area

Description
The areas where are at intensive risk, highvulnerability of urban fire hazard
The area have high risk in the factors whichlead to fire hazard
The area where fire can occur around 50%
The area with low risk and fire is difficult tooccur, it might be occur a few times

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Table 6: Factor Rating

Criteria

4
Highest Risk

Land Use
Water
Body
Fire Station
Road
Surface
Road Lane

Commercial /Industrial Area

Factor Rating
32
Moderate
High Risk
Risk
Residential
AgriculturalArea, OpenArea
Space and Park1
Low Risk
Infrastructure> 500 M.

250 – 500 M.

100 - 250 M.

< 100 M.

> 10 Km.
Far from theroad > 200 M.
1

5 – 10 Km.

3 – 5 Km.
Soil surfaceroad
3< 3 Km.
Composite
Concrete≥4

Pedestrian
2

Table 7: Weighting Criteria
Criteria
Land Use (F1)
Water Body (F2)Fire Station (F3)Road Surface (F4)Road Lane (F5)Sum

Weight
25
20
30
10
15
100 %

4.2.1 Land Use Factor

Figure 2: Land Use Classification

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4.2.2 Water Body Factor

Figure 3: Water Body Classification
4.2.3 Fire Station Factor

Figure 4: Fire Station Classification
4.2.4 Road Surface Factor

Figure 5: Road Surface Classification
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4.2.5 Road Lane Factor

Figure 6: Road Lane Classification
4.2.6 Risk Map

Figure 7: Urban Fire Hazard Risk Map

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Land Use

Water Body

Fire Station

Road Surface

Road Lane

WF1 = 25%

WF2 = 20%

WF3 = 30%

WF4 = 10%

WF5 = 15%

Nhong Jok

Bang Khun Tien

Fire Hazard Risk Map

Figure 8: Conceptual Method of Fire Risk Zones Assessment
According to the risk map, the highest risk areas can be identified into two mainzones of Bangkok; east (Nhong Jok district) and south-west (Bang Khun Tien
district). The five considered factors push these two areas to be the highest riskzones because these zones are located far from the fire station especially Nhong
Jok district which does not have even one station and there are many abandoned
land which are belonging to the private sectors without the good maintenances.
Two main zones also have low accessibility in case of transportation
infrastructure.
5. CONCLUSIONS AND RECOMMENDATIONSThis study will be more accuracy to identify the risk area by considering morecriteria or factors such as density of building, building height, building material,
fire hose location, and available fire trucks. Moreover, it is important to analyst
further in the social and economic contexts.
Furthermore, the model or scenario will be required to create the alternative planfor fire prevention and mitigation. The alternative plans can be both structure andnon-structure plan. In addition, it is possible to simulate the fire situation. Whenthe fire occurs, any organizations can play their roles including the evacuationroute and the route for fire trucks.

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6. REFERENCES
Coyle, G. (2004). The Analytic Hierarchy Process (AHP).
Hadjisophocleous, G.V. and Fu, Z. (2004). Literature Review of Fire Risk
Assessment Methodologies. International Journal on Engineering PerformanceBased Fire Codes, Volume 6, Number 1, 28-45.
Huo, X. N. (2011). Spatial Pattern Analysis of Heavy Metals in Beijing
Agricultural Soils Based on Spatial Autocorrelation Statistics. Int. J. Environ.
Res. Public Health, 2074-2089.
Hurley, M. J. and Bukowski, R. W. (2008). Information and Analysis for Fire
Protection.
Jongkroy, P. (2009). Urbanization and Changing Settlement Patterns in Periurban Bangkok. Kasetsart J. (Soc. Sci) 30, 303-312.
Nour, A. M. (2011). The Potential of GIS Tools in Strategic Urban Planning
Process; as an Approach for Sustainable Development in Egypt. Journal of
Sustainable Development Vol. 4, No. 1, 284-298
Phrommool, S. (2006). The Study on Behavior and Pattern of fire location
distribution within Bangkok District.
Saaty, T. L. (1977). A Scaling Method for Priorities in Hierarchical Structures.
Journal of Mathematical Psychology, 15(3), 234-281.
Saaty, T. L. (1980). The Analytic Hierarchy Process. New York: McGraw-Hill.
Sopholwit, et al., (2007). Integrating Remote Sensing and GIS for Fire Hazard
Zone Modeling in Kalasin Municipality Area.
Srivanit, M. (2011). Community Risk Assessment: Spatial Patterns and GIS-Based
Model for Fire Risk Assessment - A Case Study of Chiang Mai Municipality.
JARS 8(2), 113-126.
Srivanit, M. and Kazunori, H. (2011). Estimating Spatial Disaggregation of
Urban Thermal Responsiveness on Summer Diurnal Range with a Numerical
Modeling Approach in Bangkok, Thailand. Journal of World Academy of Science,
Engineering and Technology 60, 1125-1134.
Triantaphyllou, E. and Mann, S. H. (1995). Using the Analytic Hierarchy Process
for Decision Making in Engineering Applications: Some Challenge. Inter’lJournal of Industrial Engineering: Applications and Practice, Vol. 2, No. 1, 35-44.
Y, Jiaqin. And Shi, P. (2002). Applying Analytic Hierarchy Process in Firm's
Overall Performance Evaluation: A Case Study in China. INTERNATIONALJOURNAL OF BUSINESS, 7(1), 29-46.

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Ground anchors for revetment
Haruka SAITOSE Corporation, Japan
haruka_saito@se-corp.com
ABSTRACT
Ground anchors have been used in numerous projects for the purpose of landslide
control and earth retention at the time of foundation excavation. Today, theirapplications are expanding into broader areas. For instance, nut-fixed groundanchors are so highly regarded for quake resistance of the anchorage and forcorrosion prevention performance of the material that they are used to reinforce
abutments, quays, revetments and other existing structures. For example, thequake resistance improvement work for the Kobe Port Island, designed to
upgrade the functionality of the super core port, adopted a reinforcement method
using ground anchors because of the need to minimize the impact of the work on
the surrounding environment as well as the work period, cost and other factors.
This paper attempts to introduce the way to design ground anchors to reinforce
coastal facilities and cases that ground anchors are utilized for quick recovery
from the Great East Japan Earthquake.
Keywords: ground anchor, revetment
1. INTRODUCTION
Ground anchor is a system that stabilizes the structure by fixing a tension member
such as PC strands to both sides of the underground and the structure and applying
pre-stress. In case of reinforcing quays and revetments, anchor heads are fixed at
the crest of them. By applying pre-stress, these facilities improved the stability
against overturning and sliding. And also displacements caused by an earthquake
are repressed. Ground anchor reinforcement can minimize the influence on
existing facilities, therefore, it is often used to repair them without disturbing
harbor functions.
Through experiments and analyses, the method was appreciated by Coastal
Development Institute of Technology in 2009. Items were evaluated are thefollowing 4 points.
1) The effect which controls the displacement of structures caused by anearthquake is recognized.
2) The function of ground anchors can be kept to a seismic impact and vibration
by nut-fixed anchor head and compression type of anchor body.
3) Even if a tension fluctuates for an earthquake or environmental change, it ispossible to adjust by screwing a nut.
4) Double corrosion protection structure, grease and polyethylene coating, iseffective on coastal areas.

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2. APPRICATION TO REINFORCEMENT OF STRUCTURES
2.1 Design concept
The method aims to improve the stability against overturning and sliding.
Anchor load T is divided into a horizontal component (TH : Tcos) and a verticalcomponent (TV : Tsin). Against the risk of sliding, TH resists directly and TV adds
to friction resistance by increasing of the supposed weight of the structure(equation 1). Against the risk of overturning, both these force generate theopposite moment (equation 2).

  V  TV 

 H TH FS 1(1) M T  x  F M T  y
V

V

H

H

S2

(2)

Where,
V is a vertical force (kN)
H is a horizontal force (kN)MV is a vertical component of moment (kN*m)
MH is a horizontal component of moment (kN*m)
TV is a vertical component of anchor load (kN)
TH is a horizontal component of anchor load (kN)x is horizontal distance from the point applying moment (m)y is vertical distance from the point applying moment (m)is a coefficient of friction
FS1 is a safety factor to sliding (>1.0)
FS2 is a safety factor to overturning (>1.2)

Figure 1: A schematic diagram of ground anchor reinforcement
2.2 Features of ground anchor
There are 3 basis elements of ground anchors (Fig.2).
1) Anchor head – Nut-fixed system
Anchor head is a part which mediates tension between a structure and anchor
body. The system is classified into nut-fixed type and wedge-fixed type. Thismethod adopts the former exceeds in seismic resistance.
2) Cable – Double corrosion protection
Maintaining the long-term performance of ground anchor requires reliablecorrosion protection. Fig.2 gives a example of double corrosion protection, grease138

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and polyethylene coating. This structure is considered to be effective under highly
corrosive environment as coastal areas.
3) Anchor body – Compression type
Anchor body is a part which bonds to rocks through grout. There are 2 types,
tension type and compression type. Fig.2 shows a stress distribution ofcompression type. Generating stresses from the bottom of anchor body, grout isprovided compressive stresses. The structure strongly resists seismic vibrations.

Figure 2: Basis elements of ground anchor
3. Case study 1 ~ Kobe Port Island
Kobe Port Island (2nd) started using from 1998. However, it turned out that theirperformance was not satisfied with the current seismic design standard byreexamination in 2010. Because quays have already used it is necessary to choose
the method considering the utilization of them and also back yards.
The following 3 methods were compared (Fig.3).
a) Ground anchor reinforcementb) Steel pile connecting with tie-wirec) Chemical grouting

Figure 3: The comparison of reinforcement methods

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for revetment
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Ground anchor reinforcement was selected by advantages to minimize theinfluence on using ports and the cost of the construction. In this site, the layer ofclay was distributed thickly and it have not compressed enough. Therefore, thefluctuation of the tension was projected by the settlement of caisson. The structure
was designed to regulate the tension easily as changing with time. For example
setting load cells, adopting nut-fixed anchor head, putting RC lids and so on.
4. RECOVERY EFFORTS AFTER   
THE DISASTER
Most of ports located in the pacificside of East Japan were suffered by thegreat earthquake in 2011. Because of
the impact and vibrations, some quays
fell down and the ground sank. Casestudies was adopted ground anchor
reinforcement show below.
Figure 4: Locations of sites
4.1 Case study 2 ~ Funakoshi fishing port
Funakoshi fishing port is located in the middle part of Iwate prefecture. The quay
subsided by 0.26 m due to the earthquake, making it necessary to increase itsheight. However the recovery by mounding up makes it unstable for increasingpressures from back yards. Several reinforcement methods were compared (Fig.5).
As against methods widening the quay in concrete which need to excavate andremove ripraps, ground anchor reinforcement minimizes the range, term and costof the construction. It was chosen as the best method for the rapid recovery. For
reinforcing the block quay, anchor heads are fixed at the crest of the block and theblocks are pressd vertically.

Figure 5: The comparison of reinforcement methods

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Figure 6: Funakoshi fishing port, working form the land
4.2 Case study 3 ~ Shibitachi fishing port
Shibitachi fishing port is located in the north part of Miyagi prefecture. Before theearthquake it had the plan to improve the quay which had already become too old
for use. However on the way to constructing, the earthquake made a mess of it.
After reconsidering it be under reconstruction. For applying the sheet-pile quay,
anchor heads are fixed at the crest of the sheet piles using base steel plates andwales.

Figure 7: The design of the reconstruction

Figure 8: Shibitachi fishing port, working from the sea
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5. CONCLUSION
Ground anchors are useful to reinforce existing structures as using them and toreconstruct quickly. Some quays had already recovered by ground anchor
reinforcement and others still are being designed. It is hoped that this method
contribute to reconstructions and developments and put the technique to accountfor disaster control.
REFERENCES
CDIT, 2009. Technical examination and certification reports of the reinforcement
method for quays and revetments applying ground anchor. Coastal Development
Institute of Technology, Japan.
Matsuda, T., Suzuki, K. 2010. Examination of seismic reinforcement techniques
utilizing existing revetments. Proceeding of the symposium at Kinki regional
development bureau.
Takeya, K., 2013. Ground anchor structure for seismic resistance and its
applications. Earthquake-induced landslides, pp. 829-838.

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Structure maintenance methods and disastermeasures of Tokyo Metro
Hiroyuki SHINSAI1, Shinji KONISHI2, Kouichi KAWAKAMI3and Yoshihiko MUTOU4
1
Chief Engineer, Structure Engineering Division, Tokyo Metro Co., Ltd., Japanh.sinsai@tokyometro.jp
2
Assistant General Manager, Engineering Division, Tokyo Metro Co., Ltd., Japan
3
Manager, Structure Engineering Division, Tokyo Metro Co., Ltd., Japan
4
General Manager, Engineering Division, Tokyo Metro Co., Ltd., Japan
ABSTRACTTokyo Metro has 9 lines which include Fukutoshin Line open in 2008, total lengthof the lines is 195.1km. The total length of tunnels is 166.5km, about 85% of alllines. The 6.44 million passengers use our lines each day.
For keeping safety and security feeling of passengers, Tokyo Metro gives highpriority to structure maintenance and disaster measures.
This paper describes our activities for them. For former subjects, structure
maintenance by inspection, repair and reinforcement methods of subway
structures, which Tokyo Metro has been performed, are described. For later
subjects, earthquake countermeasures, seismic reinforcement and earthquake
early warning system, and anti-inundation measures of Tokyo Metro aredescribed. Lastly, the reliability of the subway is discussed with.
Keywords: subway, tunnel, structure maintenance, earthquake countermeasure,anti-inundation measure
1. INTRODUCTIONTokyo Metro, it is being checked whether it is normal by round inspection in thedaytime. Tokyo Metro has performed inspection, repair and reinforcement
efficiently within 1.5 hours at night between the last train and first train of the day,every day.
Moreover, Tokyo Metro has performed the configuration of reinforcement against
earthquake or an early earthquake alarm system after the Kobe earthquake whichsuffered the damage in which the railroad of Kansai district in 1994 was serious.
Recently, the anti-inundation measure is also performed to the guerrilla
downpours by weather change in recent years.
This paper describes the reliability and the measures of security on operating
Tokyo Metro that is introduced by details of the maintenance management(inspection, repair and reinforcement), the anti-earthquake procedures, and themeasure against flood Tokyo Metro has performed.

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2. STRUCTURE MAINTENANCE
2.1 Subject and Characteristic
Tokyo Metro has various type structures, for example box tunnel, shield tunnel,
viaduct, bridge, each structure (Figure 1). And over 65% of the structures are 40
years old and up. These structures are our targets of maintenance work. It is a
special feature that over 85% structures of all length are tunnels. We have to carryout the inspection, repair and reinforcement works within 1.5 hours at night
between the last train and first train of the day, every day. For the reason, we
maintain them with various devices and keep safety of our train service.
notes�������������������������������������������

Tunnel 166.8km

����������

（85%）

���������������

�������
��������

Open-cut 117.5km

���������

Shield49.3km�������

Bridge

5.0km

�����

（3%）

������

Viaduct����������

17.4km
（9%）

�����
�

�����

������

������

������

������

������

������

����������������

6.7km
Earth
structure（3%）

Figure 1: Length of structures by each type
2.2 Inspection
Table 1 shows contents of each inspection for Tokyo Metro’s tunnels. We made itwith referring to the Maintenance Standards for Railway Structures of the
Ministry. In general inspection, we extract and check progress of deformations
due to degradation of the lining, for example, crack, leakage and concrete flaking
etc., with observation and hammering. The worst influence on the tunnel byoccurring and developing of deformations is reinforcement corrosion due to theleakage. Once a reinforcement bar corrodes the swelling pressure due to corrosion
sometimes lead to the flaking and spalling of the cover concrete. And the spalling
has a bad influence on train safety and service. When leakage water falls on therails or signal system, some troubles will happen. On the other hand, when areinforcement bar swells by corrosion or a tunnel deforms severely by a large
external force, many cracks will occur. Therefore, in the inspection, we make atunnel soundness diagnosis with considering state of the structure, risk of aspalling and influence on facilities due to extract and check progress ofdeformations, for example, crack, leakage and concrete flaking etc. And according
to the results of the inspection, we carry repair works on a daily basis, such asleakage water stopping, taking off flaking parts and putting back the shape, torequired places. According to the results of the general inspection, we carry out an

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individual inspection of the place where a detail investigation is needed. In theindividual inspection, we investigate and measure by a suitable measuring
equipment for detecting the cause and predicting the deterioration progress withhigh accuracy. Through the activities, for some parts, we take countermeasures ofdeterioration according to the carefully work-out plan with long term view point.
The regular general inspection, which is performed once every two years, isbasically carried out by observation from the floor level. However, on the place
within our reach, we carry out a hammering test and knock flaking parts down.
For doubtful parts of its soundness on the place without our reach, we inspect indetail by the close range observation and hammering test with a temporary highstage at a later day.
The special general inspection, which is performed once every 20 years, is carriedout with the close range observation and hammering test by 4 specialists using avehicle for high place work. The team has other 6 members, a commander, two
drivers, a recorder, a photographer and a worker for cleaning of the tunnel (Figure
2).
Table 2 shows judgments of structure states and standard soundness for structural
performance. For example, C rank indicates that the structure state is slightdeterioration and A2 rank indicates that the structure state is deterioration whichmight cause a future performance drop of structures.
Judgment of structure states and standard soundness for spalling, have 3 ranks. αrank indicates the state that there is some possibility of spalling that threatens
safety in near future and flaking parts have to be knocked down immediately. β
rank indicates the state that there is few possibility of spalling that threatens safety
for the moment. But, there is some possibility of spalling that might result in
future α rank of soundness. γ rank indicates the state that there is few possibilityof spalling that threatens safety.
It is necessary to dicipline and keep skillful inspectors, because the judgment oftunnel soundness is affected heavily by skill of an inspector.
Table 1: Inspection table
Inspection

PurposeInspection
interval

Item ofinspection

Initial Inspection

Understand the initialstate of the structure

Newconstruction,
Reconstruction

Carefully
observation+α if necessary

RegularExtract thedeterioration of thestructure

2 years

Observation

SpecialImprove the precisionof judgment ofSoundness

20 years

Carefully
observation+α if necessary－

Carefully
observation
Detailinvestigations

Divide A into
subdivisions－

Observation+α if necessary

Divide into A・B・
C・S
For spalling, Divide
into α・β・γ

GeneralInspection

Individual Inspection

Presume causes of thedeterioration, estimate
the deterioration, checkof the performance
demands

Extraordinary
Inspection

Put into effect, when it
needs.

Soundness

Divide into
A・B・C・SFor spalling,
Divide into
α・β・γ

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Table 2: Structure states by each judgment
Judgment

Structure states
State that threatens operational safety of passengers, public safety, guarantee of regulartrain operation that might cause this stateA

AA

Deterioration that threatens operational safety, safety of passengers, public safety, or theguarantee of regular train operation, and require emergency countermeasures

A1

Progressive deterioration that causes the performance of structures to fall, or heavy rain,
floods, or earthquakes that might impair the performance of structures

A2

Deterioration that might causes future performance of structures fall

B

Deterioration that might result soundness rank of A

C

Slight deterioration

S

Sound

2.3 Repair and Reinforcement
The most severe problem of Tokyo Metro’s tunnels is the trouble due toreinforcement corrosion. The main cause is leakage.
The leakage of cut and cover tunnels occurs from vertical joints between sidewalls, lateral joints between construction segments and through cracks to thebehind side. The leakage of shield tunnel mainly occurs from ring joints andlongitudinal joints. In old shield tunnels, leakage is incident to occur, because
precision of segments election, backfill grout and water stopping seal of them arepoor. Once leakage happens, it’s very difficult to stop it completely.
Figure 3 shows the leakage stopping work by grouting. After the bad part wasremoved, the place was repaired by polymer cement mortar.
Next, we took reinforcement of a deformed shield tunnel with leakage for 16
years, from 1997 to 1991. We set secondary lining as reinforcement (Figure 4).
Because the reinforcement work was performed only midnight due to train service,
it took long time. But, it already finished and deformation of the tunnel stopped.

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Removing the bad part

Setting pipe for grouting

Grouting

Repairing by polymer
cement mortar

ᵓ⠏⿵ಟFigure 3: Leakage stopping work by grouting

Figure 4: Secondary lining as reinforcement
3. MEASURES AGAINST EARTHQUAKES
3.1 Anti-earthquake reinforcement (Structural measure)
Construction of the oldest tunnel in the Tokyo Metro subway network started in
September 1925. It runs from Asakusa Station on the Ginza Line to Ueno Station.
It was built after the 1923 Great Earthquake, which means all Tokyo Metrotunnels have been designed to withstand an earthquake equivalent in scale to the1923 Great Earthquake. However, when the Hyogo-ken-Nanbu Earthquake(magnitude 7.3) occurred in January 1995, a subway tunnel considered to behighly earthquake-resistant collapsed.
In view of this, Tokyo Metro has measured the ground displacement and the yieldstrength of tunnel center pillars under earthquake conditions and has carried out

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prevent tunnel collapse even when an active-fault induced, shallow inland type
earthquake equivalent to the Hyogo-ken-Nanbu Earthquake occurs.
Consequentially, protection of passengers and securing of the evacuation routes
can be assured.
Moreover, we took earthquake resistance of other structures for preventing the big
earthquake such as Hyogo-ken-Nanbu Earthquake. Some viaducts were
strengthened by steel plate winding method (Figure 6). Some bridges were set
brackets as the prevention work for bridge fall.
The Great East Japan Earthquake, which caused approximately 20,000 fatalities
and missing persons in March 2011. During the Earthquake, seismic motion of up
to 200 gals, with tremors continuing for three minutes or more, occurred in Tokyo.
Tokyo Metro had to halt train operation for at least five hours in each case.
However, post-quake inspections indicated no substantial damage to undergroundstructures, and train operation could be resumed for all routes.

Figure 5: reinforced pillars

Figure 6: strengthened viaducts

3.2 Early Seismic Alert System (Non-structural measure)
For earthquake countermeasures, we took not only structural measures but also
non-structural measures.
3.2.1 Train stop system controlled by seismographs
Regulating train operation is essential to minimizing harm to passengers due toearthquake tremors. In Japan, an earthquake alarm system called “Earthquake
Early Warning” has been provided by the Meteorological Agency since October
2007. This system detects P waves initially transmitted when an earthquake
occurs. The seismographs used for this, which are under the control of the
Meteorological Agency, are connected to alarms that are issued before the arrivalof the S wave that causes destruction of structures. Tokyo Metro utilizes anearthquake alarm system based on the Earthquake Early Warning.
Additionally, Tokyo Metro has installed seismographs at six points along its
subway lines. If any one of these seismographs detects an earthquake motion
exceeding the specified level, the trains on all routes are automatically subject toan emergency stop.

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Through the combined use of the systems outlined above, earthquake motion canbe detected early enough to stop trains before a substantial tremor occurs (Figure7). To a great extent, this can prevent derailment due to tremors and reduce
possible harm to passengers.
Th e Meteorological Agency

P waves

P waves
Earthquake generation
at seismic center

Earthquake
Early
Warning

D i stibutor

Tokyo Metro
Tra ins stop system
6 seismographs

Alert

!

Emergency stop

Figure 7: Outline of emergency trains stop system operated in Tokyo Metro
3.2.2 Raising effectiveness of equipment inspection by area seismography’s
In addition to the six seismographs that can bring trains to an emergency stop,
Tokyo Metro has added “area seismographs” at 36 points along its routes (Figure8). They are provided for the purpose of efficient inspection and confirmation of
the effects of earthquakes on structures.
The area seismographs detect the S waves that exert adverse effects on structures.
In areas where earthquake motion exceeded the specified level, inspections will bemade by walking through the tunnel after the earthquake, for a detailed
investigation to ascertain what damage if any has occurred. In areas where theearthquake motion was less than the specified level, trains will run at reduced
speeds to ensure safety.
Once area seismographs were added, inspection efficiency can be enhanced byfocusing the inspection on the route section where the earthquake motion issubstantial. In this way, the time from the occurrence of the earthquake toresumption of operation can be reduced.

Figure 8: Seismographs installed along Tokyo Metro lines
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4. ANTI-INUNDATION MEASURES
4.1 Estimation of Damage and Targeted places
The light green part in Figure 9 indicates the damaged area due to bank rip of the
Arakawa River where Ministry supposed. Some color lines show train service
lines of Tokyo Metro. The light pink part in Figure 9 indicates flood hazard mapof Tokyo Metropolitan Government and the part is the supposed flooded area
when Kanda River, Sumida River or other rivers flood by a heavy rain. Because
the maps indicate inundation height of each point, we make the plan of antiinundation measures on the data of the map.

Figure 9: Inundation map of Tokyo
4.2 Anti-Inundation Measures
Subway tunnels are prone to inundation when flooding occurs. Inundation not
only makes train operation impossible, it also exposes passengers to harm. Tokyo
Metro is taking various measures to prevent inundation. Targeted points of antiinundation measures are gate ways of underground stations, tunnel entrances andvents.
4.2.1 Cut-off plate and waterproof door at gate way of the station
Cut-off plates or waterproof doors are provided at subway entrances and exits toprevent inundation when flooding occurs. In the normal state, the cut-off plate(Figure 10 left) is housed near the gateway. They are set up to prevent inundation
when the risk of inundation increases due to heavy rainfall. The cut-off plates,
which are about 70 cm high, can be climbed over by passengers when tunnel
evacuation is necessary.
For certain stations located in lowland areas in the eastern parts of Tokyo or nearrivers, waterproof doors (Figure 10 right) are also set up at the gateways toprepare for cases in which a cut-off plate would not be enough to prevent
inundation. The waterproof doors can protect station entrances and exits, ensuringthat inundation of the tunnels will not occur. Stations with low areas have thewaterproof doors, and they are provided with elevated gateways for further
prevention of inundation.

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Figure 10: Cut-off plates and waterproof door at subway entrances and exits
4.2.2 Inundation prevention devices installed at vents
The subway tunnels have vents at various locations. Vents at road surfaces could
allow large volumes of water to flow into tunnels when heavy rain or flooding
occurs. As a countermeasure, inundation prevention devices (Figure 11) areprovided at vent opening on roads. The devices can be remotely controlled from acentral operation panel in stations. As they receive information on conditions
during heavy rain, station personnel can close the vent before any inundation
occurs. In addition, as a means to cope with unexpected localized heavy rainfall,each vent is provided with an inundation sensor that closes the vent automaticallywhen inundation is detected. Improvements are being made to these mechanisms
to enable resistance to water pressure at a depth of six meters.
water

perception device

tunnelFigure 11: Vents and inundation prevention device
4.2.3 Waterproof gate
The possibility of large-scale floods occurring due to heavy rainfall or a storm
surge is high in areas near rivers or in the lowlands spreading to the east of Tokyo.
Moreover, these areas could suffer inundation if a tsunami is caused by anearthquake. In the plateaus on the west side of Tokyo, some subway routes havetunnel openings near a river, which poses the risk of water overflowing into thetunnel when localized heavy rainfall occurs.
To prevent large-scale inundation into tunnels, Tokyo Metro has installed
waterproof gates (Figure 12) at seven locations in the tunnels. Each of these gates
protects the full section of the tunnel to minimize damage and harm to passengers

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Vietnameven in the event of large-scale inundation. These gates are installed around theopening of tunnels in lowland areas, near rivers, and in tunnels running deep
below the rivers. Gates can be closed electrically, hydraulically or manually. The
time needed to close them is 2 to 4 minutes for hydraulic operation, and 15 to 20
minutes for electric operation. Maintenance work on the waterproof gates is done
once a year, using test operation, an air-tightness test, an inspection of electricalequipment parts, and a test of the hydraulic system.
Water entering a tunnel in spite of the waterproof facilities is discharged outside
the tunnel by means of drain pumps provided at various locations.

Figure 12: Waterproof gate at normal times and during flooding
5. CONCLUSION
Subway tunnels are a key link in the infrastructure in large cities. Since tunnels
are spaces isolated from the ground level and pathways that can be used forevacuation are limited, they are exposed to serious risks in the event of a disaster.
Tokyo is frequently hit by typhoons and localized heavy rainfalls every year, andit faces the risk of earthquakes. Therefore, securing the safety of subway tunnels
becomes an important and difficult task. Without succumbing to thesedisadvantages, Tokyo Metro is implementing structural and non-structural
measures for the major purpose of securing safe and stable train operations, while
assigning top priority to the safety of passengers. Tokyo Metro will not besatisfied with what has been done (as outlined in this paper). It will proceed withefforts to improve and renew disaster-prevention facilities. Tokyo Metro
continues efforts daily to enable as many passengers as possible to safely use its
subways.
REFERENCES
Tashiro, Y. and Mutou, Y, 2013. Disaster-Prevention Measures for Tokyo Metro
Tunnels. World Tunnel Congress 2013, Switzerland-Geneva.

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For the safety and the sustainable
development of Ho Chi Minh City
Ngoc Tran NGUYEN
Professor, Director of Mekong River Delta Development Research Center
nntran2010@gmail.com
ABSTRACTIn every country, a megacity has strong impacts on the economy, the environment
and the society, and vice versa is influenced by these factors. Therefore, Ho Chi
Minh City, an Asian megacity in a near future, should be approached in terms of
economic, social, environmental aspects and governance. The tasks are
increasingly necessary in the context of economic globalization and global
climate change. This paper refers to a number of urgent issues according to theauthor’s opinion. Science and technology have a lot of tasks to make practicalcontributions to the safety and the sustainable development of this upcoming
megacity.
Key words: Ho Chi Minh City, FDI, rich-poor gap, environment, sustainable
development.
I. ABOUT MEGACITIESA megacity is understood as a city with the population of over 10 million
inhabitants. With this understanding, the list of the world’s megacities is changing
and constantly increasing.
In 2007, Megacity Challenges report [1] surveyed 25 cities of which 21 arestandard megacities with at least 10 million people.
According to McKinsey Global Institute [2], in 2007, there were 23 megacities in
the world. Ranked by population from high downward are: Tokyo, Mumbai,
Mexico City, New York, São Paulo, Shanghai, Kolkata, Delhi, Beijing,
Chongqing, London, Dhaka, Buenos Aires, Los Angeles, Karachi, Cairo, Rio deJaneiro, Paris, Rhein-Ruhr, Osaka, Manila, Moscow and Istanbul. These 23
megacities account for 5% of the world's population and generate 14% of the
global GDP.
Forecasting the growth of megacities by 2025, based on data of 2007, theMcKinsey Global Institute (MGI) considers further 600 cities, called The City 600
by MGI, composed of 23 megacities, 45 large middleweight cities, 143 midsize
middleweight cities, and 389 small middleweight cities 1 (Figure 1).

A middleweight city has a current population between 150,000 and 10 million. Small: 150,000–
2 million; Middle: 2 million–5 million; Large: 5 million–10 million).

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In 2007, The city 600 accounted for 22% of the global population and generated
54% of the global GDP.
In The city 600, the developing countries had 16 megacities (69.6%), and 407
Cities 600 (67.8%).
To emphasize the importance of megacities, two criteria usually considered are
the rate of population and the rate of GDP of megacities over the world populationand the global GDP.
For a megacity of a nation, two corresponding criteria are the rates of population
and GDP over the population and the GDP of the country.

Figure1. The city 600 in the world (MGI 2007)
Among 23 megacities listed by MGI, the Asia has 11: Tokyo, Mumbai, Shanghai,
Kolkata, Delhi, Beijing, Chongqing, Dhaka, Karachi, Osaka, and Manila.
F. Krass and U. Nitschke (2008) [3] introduced their forecast of megacities in
Asia in 2015 (Figure 3)

Figure 3. Asian megacities in 2015

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It can bee seen that the great majority of megacities (or those soon to become
megacities) are in the developing countries. This is true not only in Asia, but also
on the global scale, as seen when talking about The city 600.
2. HO CHI MINH CITY, A MEGACITY IN A NEAR FUTURE
Table 2 provides the results of the census in the whole country and in Ho Chi
Minh City in 1979, 1989, 1999 and 2009.
Table 2. Data of the census in Ho Chi Minh City
POPULATION OF HO CHI MINH CITY OVER 4 CENSUSES
Ho Chi Minh 01.10.1979 01.10.1989
01.4.1999
01.04.2009
City
Total
3,419,9783,988,124
5,037,155
7,162,864
in urban area
2,700,849
2,946,426
4,204,662
5,968,384
in rural area
2,719,129
1,041,698
832,493
1,194,480
Ratio urban/rural 79.0%
73.9%
73.9%
83.3%
Male
1,622,072
1,890,343
2,424,415
3,435,734
Female1,797,906
2,097,781
2,612,740
3,727,130
The growth rate of the population every 10 years significantly increased: 16.6% in
1989 compared to 1979, 26.3% in 1999 compared to 1989, 42.2% in 2009
compared to 1999.
The ratio of urban population over total population in Ho Chi Minh city decreased
in 1989 compared to that in 1979, and highly increased in 1999 and in 2009.
The above comments are clearly illustrated through the growth of residential builtin land in which construction has been made in the land-use maps in 1985 and2010 of the city (Figure 4)

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Source: Ho Long Phi et al. (Personal communication of Ho Long Phi)
Figure 4. Map for land use of Ho Chi Minh City in 1985 (left) and 2010 (right)
The GDP growth of Ho Chi Minh City over 20 years (1990-2011) is quite rapid,
from 17,993 to 166,423 billion VND (1994 compared value), accounting fornational GDP from 13.63% to 28, 49% (Figure 5)

Figure5. National GDP, GDP of Ho Chi Minh City and ratio
In the 1980s, developed countries promoted foreign direct investment with theaim of seeking for high profits from abundant and cheap human resources in thedeveloping countries.
This intention coincides with the "thirst” for capital and technology of thedeveloping countries. This is time for the arrivals of foreign direct investment inthese countries in the early 1980s [4].
After that, trade liberalization, economic globalization and the establishment of
the World Trade Organization WTO, instead of the General Agreement on Tariffs
and Trade GATT, in 1995, expanded direct investment to the indirect investment.
The concept of trade henceforth included goods, intellectual property and services,
particularly financial services. This means for the developing countries at thesame time opportunities interlaced with challenges to receive investment fromoutside.
Industrial parks, offices, hotels, villas, luxury apartments and recreational
facilities along with transportation infrastructure, communications grew rapidly.
Opportunities for employment attract human resources in different qualifications.
Thanks to that, the urban appearance has been also more modern and spacious.
These are "pushes" for the rapid formation of megacities in developing countries.
It should be also added that some megacities in Asia was formed associated withservices in the Vietnam War during the years of 1960 - 1970 and then when
Vietnam faced embargo until the mid 1990s.
Law on foreign direct investment in Vietnam was first issued in 1987. However,capital flow of foreign investment actualy arrived into Vietnam in general, and Ho
Chi Minh City in particular, only since the mid-1990s after the United States lifted
the embargo and normalized relations with Vietnam.
The number of FDI projects and total investment capital valid till 31.12 every year
has steadily increased since 1995 so far (Figure 6).

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With this momentum of development, in a short time, it is no doubt that Ho Chi
Minh City will become an Asia's megacity.
Among causes for the rapid development of Ho Chi Minh City, state management
factor has exploited the needs of multinational companies investing into foreigncountries, and catched the opportunities opened by the trade liberalization, in
combination with promoting resources and the geographical - political - economic
position of the City and the country.
However, together with those opportunities, there are a lot of economic, social,environmental and state management challenges.
FDI VALID TO 31/12 ANNUALLY

Source: Department of Statistic of Ho Chi Minh
Figure 6.Number of projects valid to 31.12 annuallyand total corresponding investment
3. SOME FACTORS AFFECTING THE SAFETY OF HO CHI MINH CITY
3.1. With regard to the economy
Since the rapid growth of the economy depends mainly on the foreign investment,
this fact itself contains risks of unsafety, when capital flow from outside, for somereason, decreases. Therefore, developing the internal resources of the economy isa task of strategic significance.
In an increasingly globalized economy, the crisis can occur from another country.
The 2007 financial crisis started in Thailand and the 2007 economic crisis erupted
in the United States have impacted on the worldwide economy, on Vietnam and
Ho Chi Minh City in particular. Recently, countries and cities experiencing (or on
the edge of) bankruptcy have provided experiences and lessons of how must be an
active integration.
While focusing the investment for Ho Chi Minh City, the city’s leaders takeinterest for the suburban and the rural areas of the City.
The development of Ho Chi Minh City has to be associated with the Southernmajor economic area and to link with the Mekong Delta, to promote each other's
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strengths and cooperation for the mutual development. Moreover, humanresources necessary for the development of the City come from all over thecountry, the southern provinces at first.
The above guidelines, correct and necessary for the safety and the development of
Ho Chi Minh City, must be pursued with more and more efficiency.
3.2. With regard to the society
Among number of issues, the one should be paid most consideration is the povertyof the urban people because of its significance for the social cohesion, the safety
and the sustainable development of the City.
According to the report Ho Chi Minh City, 35 years of establishment anddevelopment [5], the growth rate of GDP per capita of the City is as follows:
Table 4. Growth rate of GDP per capita of Ho Chi Minh City
76-80
1.32

Gdp Growth Rate Per Capita Of Ho Chi Minh City
81-85
86-90 91-95
96-00
01-05 06-10
2.96
5.57
9.97
7.16
7.51
7.32

From 1996 to 2008, the proportion of households with usual living facilities
increased regularly.
The elimination of a great number of practically insolvable slums, and "black
water hamlets" existed before inside the City, is a renown of Ho Chi Minh City.
Paying continuous attention to citizen in general, migrant workers and especiallythe poor, is a just policy of the City and needs to be continued since many social
issues, starting points of social evils, remain to be solved.
Recently, the project "Monitoring Urban Poverty 2008-2012" by Oxfam Vietnam
has investigated the poverty status of the urban people [6].
According to the project, "in the last 5 years (2008-2012), life of majority of theurban poor at monitoring sites has been improved. (...) Urban poverty in Viet Nam
reduces gradually if looked at only income or expenditure terms, even if thepoverty line is raised. However, once other dimensions are considered, urban
poverty remains a concern."
Multidimensional poverty is understood the lack of basic shortages which prevent
uninterruptedly the urban poor from escaping the poverty.
For the native poor, there are five basic shortages: "lack of labor and skill", "lackof capacity to find alternative livelihoods", "lack of social capital", "limited accessto public services", "uncomfortable and unsafe living environment”.
Five basic shortages for the migrant poor are: "high living costs", "unstable
employment", "lack of social integration", "limited access to public services",“uncomfortable and unsafe living environment”.
The report concludes: If the challenges are not properly dealt with, quality of livesof the local and migrant poor will remain low, their vulnerability will be high, andthe inequalities will continue to be increased.

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The eight recommendations for action on poverty in urban areas proposed by thereport should be paid much concern.
3.3. Environment and flood situation in the City
Traffic congestion, air, sound, water pollutions, flood due to heavy rains and hightides, and greenhouse gases emitted are increasingly urgent issues that Ho Chi
Minh City have to solve the sooner the better in order to avoid heavy difficulties
encountered by other Asian megacities.
Frequent flood situation in the City causes effectively many obstacles for
production activities, business and life of the inhabitants and needs to receive
adequate solutions.
Ho Chi Minh City borders with the East Sea at Can Gio district by a dense
network of rivers and canals. Its center is 50 km crow-fly far from the sea.
Therefore, the City is strongly affected by the climate change and the sea levelrise. Preserving the Can Gio mangrove forest in this context not only means
conserving the green lungs of the City but also means responding to climatechange.
Ho Chi Minh City is at the confluence of Dong Nai, Sai Gon, Vam Co Dongrivers flowing into the East Sea by a network of channels in which the mostimportant are Soai Rap and Long Tau rivers through which the tides come into theCity.
In recent years, the situtation of flood in the city has been happened more often
along with tides and heavy rains. Water resources institutions have proposed
measures to prevent flood such as: placing dikes and sluices along the Vam Co
Dong and Soai Rap rivers (Figure 7). These are quite expensive solutions
generating the profound environmental changes while effectiveness is yetmonitored and evaluated.

Figure 7.Work solution of irrigation sector (stage 1)

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Flood in the city depends on the hydrological regime of the rivers and the tidal
amplitude in the estuary. It aslo depends on the water drainage system of the City,
on the natural and the accelerated land subsidence in the area.
The designed capacity of the water drainage system of the city depends on many
parameters such as population, rainfall in the basin, the area of the water storage
and absorption zones etc... Therefore, when the basin surface becomes
imperviable where it was pervious and/or capable to store water before, thenvolume of water drained into the river will be more and more rapid, causing waterdrainage system and rivers overloaded
Figure 8 shows the remarkable decline of the water storage and absorption since
the urbanization of Ho Chi Minh City so far (See also Figure 4 for the rate ofurbanization).
Accelerated subsidence is caused by groundwater surexploitation, mining,
construction of buildings and urban infrastructures.
Since the 1990s, the City has begun its urbanization, hundreds thousands of cubic
meters of groundwater has been exploited every day, especially in new urban
areas. Groundwater levels of the city have decreased over 20 meters since 1990,
significantly contributing to the deformation of the ground of city.

(Personal communication from Ph.D. Ho Long Phi)
Figure 8. Decrease in area of water storage and absorption of Ho Chi Minh city)
The primary measured results of PS InSAR technique shows the strain rate withrange from -10 to +8 mm / year (Figure 9) and the subsidence in some areas in the
inner City of 30 mm during the period from 1996 to 2003 [7].

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Source: L.V.Trung, H.T.M.Dinh (2009)
Figure 9. Ground deformation in Ho Chi Minh City (1996-2002)
Analyzing hydrological data from 1988 to 2008 shows that during this period at
Vung Tau station the increase trend of the highest annual high tide level on
average is of 3.88 mm / year while at Phu An station that is 14.23 mm / year, 3.7
times higher than in Vung Tau [8]. Does this increase derives from internal
impacts in areas of Saigon and Dong Nai rivers? That is a main question the
research of anti-flood measures for HCMC has to clarify.
4. FOR A SUSTAINABLE DEVELOPMENT OF HO CHI MINH CITYWith a population of 7.7509 million people in 2012, excluding the number ofresidents without registration in the area, the fact that Ho Chi Minh City becomesa megacity in the future is obvious. However, as seen above, to make it a safety
megacity with sustainable development, Ho Chi Minh City has to deal with many
issues.
The City should refer to the achievements and especially the difficulties andchallenges faced by Bangkok, Manila, Jakarta in its development process, to learn
therefrom necessary lessons and experiences, particularly in the context of climatechange [9].
Global Summit on sustainable development in Johannesburg in 2002 agreed thatfor sustainable development, it should be based on three main pillars: economic
growth, social equity and progress, and environmental preservation [10].
Economic growth and social equity and progress satisfied, but the environment
degraded and exhausted will not provide sustainable development.

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Economic growth and preserved environment satisfied, but persists and enlarges
the fracture between rich and poor, it also will not be able to develop stably.
A development model in which the results of achievements are equally divided for
all the people, the environment is protected, but the economy is not growing, thismodel will not survive long time, especially in a world with fierce competitionand large exchanges.
Figure10. Sustainable development modelSocial equity
and progress

Sustainable
Environment
preserved

Economic
growthA nation or a city can only develop sustainably when its development model liesin the intersection of three circles Economy, Society, Environment, i.e the model
must ensure simultaneously economic growth, equity and social progress, andenvironmental preservation (Figure 10).
To develop such a model, the prerequisite is that a nation or city must be wellgoverned.
In all four sectors economic growth, environmental protection, equitable,
democratic and civilized society, and good governance, as seen above, Scienceand Technology can participate largely and effectively.
I would like through this paper, share with the Conference some ideas to make Ho
Chi Minh City a safe and sustainable megacity.
REFERENCES[1] GlobeScan and MRC McLean Hazel, Megacities Challenges, A Stakeholder
Perspective (2007), Research Project sponsored by Siemens.
[2] McKinsey Global Institute, Urban World Mapping the Economic Power ofCities, 2011.
[3] Krass F., Nitschke U. (2008), Mega-urbanisation and Global Change in Asia:
Processes, Problems and Perspectives,
Kraas, F. (2007): Megacities and global change: key priorities. Geographical
Journal 173 (1): 79-82.
[4] Nguyen Ngoc Tran, Foreign Direct Investment in Some of current global
economic issues, 109-184, Thế Giới Publishing House, 2003, in Vietnamese.

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ICUS Report 73[5] Ho Chi Minh city Development Research Institue, Ho Chi Minh city, 35 years
of establishment and development (1975 – 2010), 2012, Ho Chi Minh City
General Publishing House, in Vietnamese.
[6] Oxfam Vietnam, Poverty reduction in Vietnam: new challenges, newapproach, 2012, http://oxfaminvietnam.wordpress.com/resourcesbao-cao/[7] L. V. Trung, H. T. M. Dinh (2009). Monitoring Land Deformation Using
Permanent Scatterer InSAR Techniques (Case study: Ho Chi Minh City). The
7th FIG Regional Conference on Spatial Data Serving People: Land
Governance and the Environment – Building the Capacity. Hanoi, Vietnam,
19-22 October 2009.
[8] Nguyen Van Dang, Nguyen Ngoc Tran, Changes in rain and water level in
Nam Bộ. Analysis of hydrological data in the period of 1988-2008. Technicalreport of Mekong Delta Development Research Center (MDDRC), February,
2010.
[9] World Bank, Climate Risks and Adaptation in Asian Coastal Megacities. A
Synthesis Report, September 2010.
[10] Nguyen Ngoc Tran, Johannesburg Submit Conference 2002 and Sustainable
Development, in Small Stones for the Sustainble Development, p.30-38, Tre
Publishing House, 2011.

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History and recent trend of Tokyo Metro’s
tunnel construction technology
Shinji KONISHI1, Satoshi ITO2, Takashi HIRANO3
and Kazufumi NOYAKI４
1
Assistant General Manager, Engineering Division, Tokyo Metro Co., Ltd., Japans.konishi.r4r@tokyometro.jp
2
Construction Work Office Manager, Renovation & Construction Department,
Tokyo Metro Co., Ltd., Japan
3
Design Section Assistant Manager, Renovation & Construction Department,
Tokyo Metro Co., Ltd., Japan
4
General Manager, Renovation & Construction Department, Tokyo Metro Co.,
Ltd., Japan

ABSTRACTThe Construction of the first subway in Asia was started in 1925 and operationof it was started in 1927, 87 years ago by the former Tokyo Metro Company. Thisis a part of the Ginza line, between Asakusa and Ueno in Tokyo. Since the event,
we constructed a lot of lines. Now, we operate nine subway lines with 195.1
kilometers of track that predominantly serve Tokyo’s 23 wards and carry 6.4
million passengers each day.
The report introduces some topics of our construction history for new subway
lines. After that, it describes recent two cases of tunnel construction, The
Fukutoshin line and the Kotake-mukaihara bypass tunnel, with discussing trend ofrecent technology for tunneling.
Keywords: subway, neighboring construction, shield tunnel, traffic networking

1. INTRODUCTION
The chronological table of subway construction in Tokyo Metro is shown in
Figure 1 (Renovation & Construction Department, Tokyo Metro Co., Ltd., 2005).
Figure 2 shows the distance ratio of cut-and-cover work and shield tunnel
construction in each line. Now, 70% of total tunnel length, 166.8km, is cut andcover tunnel and 30% is shield tunnel. The evolution of cut and cover technology
in Tokyo Metro is shown in Figure 1. The epoch-making changes are that steel
materials started to be used for temporary materials from 1960’s and underground
diaphragms started to be adopted for earth-retaining wall from 1970’s. Owing to
the evolutions, wider and deeper underground space can be constructed safely by
the cut and cover method. After that, fundamental techniques of cut and covermethod haven’t evolved remarkably without some auxiliary methods,
underpinning method and information-oriented construction.
However, technical innovation of shield tunneling method advanced
remarkably in recent years. Therefore, over 70% new tunnels of Tokyo Metro are165

October
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Vietnamconstructed by shield tunneling method. In this paper, the construction history ofTokyo Metro’s tunnel, with focus on shield tunneling method, is described.
Then, it describes recent two cases of tunnel construction, the Fukutoshin line andthe Kotake-mukaihara bypass tunnel, with discussing trend of recent technology
for tunneling, because new technologies were applied for the two tunnels with theobject of reducing costs and environmental load.
Line\Year 1920

1930

1940

1950

1960

1970

1980

1990

2000

2010

Ginza
Marunouchi
HibiyaTozai
ChiyodaYurakucho
HanzomonNanboku
Fukutoshin

Figure1: Chronological table of subway construction in Tokyo Metro
Cut-and-cover
ShieldTable 1: Number of open typeand closed type shieldtunnels
Year
-1965
-1970
-1975
-1980
-1985
-1990
-1995
-2000
2001Total

Open type3 tunnels
16 tunnels
21 tunnels
20 tunnels
1 tunnels
1 tunnels
62 tunnels

Closed type1 tunnels
5 tunnels
9 tunnels
11 tunnels
22 tunnels
10 tunnels
58 tunnels

Figure 2: Distance ratio of cut & cover and shield tunnel

2. HISTORY OF TOKYO METRO’S TUNNEL CONSTRUCTION
2.1 Shield tunnel
Table 1 shows the number of an "open type shield tunnels" and a “closed typeshield tunnels" every five years. Tokyo Metro already constructed over 130 shieldtunnels. At first, a tunnel of the Marunouchi line was constructed by roof shield

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method in 1957. Next, full-scale circular shield tunnel was adopted for the Touzai
line in 1964. Nowadays, the method is used not only for the tunnels between
stations but also stations. Shield tunneling method was used for around 75% of alltunnels recently. Since 1980’s, closed type shield started to be applied. The“closed type shield” is the most common type used over the past 20 years.
Recent topics of shield tunnel evolutions are increasing in size of the crosssection and diversification of the cross section shape. The 10m across in diameterclass shield tunnel, like subway tunnel, had the largest cross section previously.
Subsequently, large size tunnels with from 11m to 14m across in diameter wereconstructed, because the method was adopted for the underground retention basin,
underground river and underground road tunnels.
The biggest railway shield tunnel in Japan, which has 13.92m across indiameter and has 3 track lines, was constructed in the Nanboku line of Tokyo
Metro, opened in 2000 (Figure 3). Technical summaries of the large scale tunnel
are shown in below.
1. To keep tunnel face stability with large difference of earth and waterpressure between the crown and bottom of the tunnel face.
2. To have the full mixing capacity in a chamber and earth-removing capacity.
3. To keep high accuracy of the shield machine and segments.
4. To equip the full cutting power coping with increase of cutting torque.
Regarding the diversification of cross section shape, a round shape is the main
shape of shield machines as yet, because of advantages of simple rotation
structure with one axis and strong ring structure. However, multi circular shield,
such as double faced shield and triple faced shield, are applied recently, as shownin Figure 4. Moreover, elliptic-type shield, rectangular-type shield and compoundcircular shield (Figure 5) were developed for these 10 years due to the necessity.

Figure 3: Mother and childshield machine

Figure 5: Compound circular shield

Figure 4: Triple circular typeshield machine

Figure 6: Transition of shield tunnel shape
between stations in Tokyo Metro

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October
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Metro. Circular tunnel of single-track type, double track type and three-track typeare standard. However, compound circular shield was developed and applied in
Fukutoshin line of Tokyo Metro.
2.2 Station by shield tunnels
Figure 7 shows the transition of shield station tunnel shape. In old times, 1970’s,
the enlarge method between two shield tunnels by mining were used generally.
However, the method need very complicated processes with dangerous work, longterm and high cost. The station tunnels come to be constructed at one stroke by amulti circular face shield machines with the advance of technology, because themethod can improve safety, term and cost of the construction work.
An example of station tunnel construction method with a removable triple
circular shield machine is shown in Figures 8, 9. The method was used for theconstruction of a part of the Nanboku line in Tokyo Metro and can construct astation and tunnels between stations with one shield machine, because themachine can be changed its cross section with putting on and taking off the bothside shields.
Figure 10 shows a construction method of the double track tunnel and triple
track tunnel with one shield machine (Figure 3). The machine is the mother andchild shield machine. The ultra-large shield machine, the mother shield machine,with a diameter of 14m has a shield machine, the child shield machine, with adiameter of 10m build-in.
The triple circular type shield machine with same diameter, is shown in Figure
4, was used for construction of a station tunnel and triple tracks tunnel in the
Hanzomon line of Tokyo Metro. The machine has two circular cutting heads with
one axis respectively on both sides and a shaking cutter in the middle part.

Figure 7: Transition of shield station tunnel shape in Tokyo Metro

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Figure 8: Construction method with the removable triple circular shield machine

Figure 9: Removable triple circularshield machine

Figure 10: Construction method withir
the mother and child shield machine

3. RECENT TREND OF TOKYO METRO’S TUNNEL CONSTRUCTION
3.1 Construction of the Fukutoshin line
The Fukutoshin Line, 11.9km in length and opened Jun.2008, is a subway whichconnects three leading shopping districts (Ikebukuro, Shinjuku, Shibuya) inTokyo (Figure 11). Altogether, ten shields were used for tunnel construction
including stations (Nishimura, 2012). They include machines for two special
shield tunneling methods. They are the compound circular shield and mother-andchild shield.
3.1.1 Compound circular shield
The compound circular shield is the shield made combining circles with threedifferent curvatures. It was adopted for usage in tunnel construction between the
Meiji-jingumae station and Shibuya station. Because the width is greater than theheight, expand-and-contract cutters at the end of the spoke of the shielding
machine are attached (Figure 5). The red portion in the figure is the "expand-and-History and recent
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Vietnamcontract cutter." Although this spoke rotates and it excavates underground, if aspoke comes upwards, the red portion will withdraw.

alignment

Ikebukuro

longitudinal cross section

ShibuyaS h i n ju k uFigure 11: Alignment and longitudinal cross section of the Fukutoshin Line

A : Circular
B : Compound Circular
A/B

Figure.12: Form of compoundcircular tunnel

Space area
46.95m2
46.05 m2
0.98

Digging area
73.90 m2
67.30 m2
0.91

Figure13: Comparison with a circular andcompound circular shield

Figure 12 shows the tunnel form seen from above. Figure 13 shows acomparison with a circular shield and compound circular shield. The area of thespace of a tunnel will be 98% and has almost the same space. However, thedigging area will be 91% therefore reducing 9%. So, this shield tunneling method
is very good for the environment and cost.

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Figure 14: Construction method with the mother & child shield machine
3.1.2 Mother-and-child shield
The mother-and-child shield machine is used for the construction method adopted
for construction of both stations and tunnels between stations (Figure 14). By
using this one machine, we could reduce cost. With this one mother-and-childshield machine, tunnels of two different sizes can be built. The machine has the
structure which included the small shield (called "child shield") inside the large
shield (called "mother shield"). When the "mother shield" reaches theintermediate shaft, we extract the "child shield", and re-start the "child shield" tobuild the structure.
3.2 Construction of the Kotake-mukaihara bypass line
3.2.1 Outline of the Kotake-mukaihara bypass line
The new bypass line is located between the Kotake-mukaihara and Senkawa
station on both the Yurakucho and Fukutoshin Lines. Figure 15 shows the present
state and the improvement plan of this level crossing section (Noyaki, 2011). Here,the line from the north-western area of Tokyo (Nerima) comes in to join thealready existing parallel sections of the Yurakucho and Fukutoshin Lines. The
operation pattern here is extremely complicated, including the four routes shownin Table 2. A seamless network has been established by planning the levelcrossing between Route (2) and Route (3). As the train interval becomes tight
between Routes (2) and (3) in this level crossing section, the following train has tostop temporarily before crossing to wait for the preceding train to pass. This
causes a delay in the diagram. For this reason, the bypass tunnels for the
Yurakuchou line between the Kotaemukaihara and Senkawa station wereconstructed and the level crossing section was removed.

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Table 2: Operation patternsNoTo thestarting
pointcrossing

StationNerimaNo(Yurakucho

StationLine)(Seibu
2

Level

point
Shin-kibaTo
1

To the terminal

Shibuya Station

Yurakuc(Fukutoshin

ho Line)

Yes

Line)
Shin-kiba

3

StationTo(Yurakucho

WakoshiLine)

StationShibuya Station

4

Yes(Fukutoshin

No

Line)

Figure 15: Present state and the improvement plan of this level crossing section

Fig.16: Plan view of the Kotake-mukaihara bypasses line

Scope of connecting structure work about
410 m
Senkawa Station
To W

To Shinkiba (Yurakucho Line)

Wakoshi– Nerima

To Shibuya (Fukutoshin Line)

Mukaihara-side
cut-and-coversectionShieldtunnelsectionSenkawa-side cutandcoversectionNew structure
LegendExisting structure

Fig. 17: Vertical sectional view of the Kotake-mukaihara bypasses line

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Approx. 21m
Approx. 20 -Approx. 36 - 38m

5.5m

5.5m

Shield tunnel section

Mukaihara-side cut-and-cover tunnel section

LegendApprox. 20～

Newstructure

Structures removed
Existing
Approx. 24～

structures

Senkawa-side cut-and-cover section

Fig. 18: Sectional view of the structures
Because of the traffic congestion problem, environment problem of noise andvibration, cost reduction and shortening of construction period, the improving area
was decided to be approximately 410m and the structures were divided into three
sections:(1) A cut and cover tunnel on the Mukaihara side(2) A shield tunnel section(3) A cut and cover tunnel on the Senkawa side
The scope of each structural type is shown in Figures. 16, 17 and a sectionalview is shown in Figure. 18
The cut and cover tunnel had to join into the existing tunnel. Therefore, at firstthe bypass tunnels were set on side or top of the existing tunnels. Then, side walls
and upper slabs of the existing tunnel were removed. The work was very difficult,because it was ultra-adjacent construction to the rail track under operation.
However, we completed the work without any problem due to the detailed
construction plan and suitable process.
3.2.2 Shield tunnel section
The sectional shape of the shield tunnel section was decided to be the combinedcircular section as shown in Figure 19. The principal objectives are as follows:(1) Securing sufficient distance from private land.
(2) Securing sufficient distance from existing structures.
(3) Reducing the environmental impact by reducing the sectional area.
Table 3 shows the comparison of the sectional area relative to the circular section.
History and recent trend of Tokyo Metro’s tunnel construction technology
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R3

Table 3: Comparison of the sectional area relative tothe circular section

R2

R1

Tunnel internal
Excavation
space area
sectional area
A: Circular(Ф6.6m)
34.21m2
26.48m2
2
B: Combined-circular
31.15m
23.64m2
B/A
0.91
0.89
R1=5500mm, R2=7800mm, R3=2000mm(Combined-circular: H6.6m x W5.5m)

Figure 19: Combined circular section

Figure 20: Details of the shield machine
The use of a combined-circular section enables securing trouble-free internal
space for subway operation while reducing the sectional area by 10% from thecircular section. The segments used were reinforced-concrete designed after
considering the working load and economy. The segment thickness wasdetermined on the basis of the thickness needed in terms of design, while attempts
were made to reduce the thickness to secure an internal section (construction
gauge) needed for subway operation. The thickness was set at 300 mm and width
was set at 1,500 mm. For splitting, a six-part unequal split was utilized based onan overall consideration of the assembling workability of K-type segments and to
reduce water leaking points after opening for service.
A 5,700 mm W × 6,800 mm H high-density slurry shield machine was used forshield tunnelling (Figure 20). On the purpose of reduction of the construction costand environment load, we constructed the Route B tunnel by reusing the principal
components, such as the cutter head, soil discharge system, erector, shield jack,and shape protection unit that had been used for the preceding Route A.

4. CONCLUSION
The report introduced some topics of our construction history for new subway
lines. After that, it describes recent two cases of tunnel construction, The
Fukutoshin line and the Kotake-mukaihara bypass tunnel, with discussing trend ofrecent technology for tunneling.

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Lately, Tokyo Metro has been engaged in wide variety of tunnel improvement
projects to improve railway services by securing stable transportation, alleviatingcongestion, and ensuring safety. Our aim is to provide a convenient subway
network for the future, thereby contributing to social development. In thesituation, construction method shifts to the methods that can be reducing thevolume of excavated soil, operation procedures and operation time for the purposeof reducing construction cost and environment load. Moreover, the construction
method which can use leaved small underground space is requested now.
Tokyo Metro will continue to make every effort to challenge to develop andapply new techniques and improve the quality of the subway services it provides.

REFERENCES
Nishimura, T., 2012. Performance of the Construction of Tokyo Metro Line No.
13 -Application of new technology and cost reduction policy-. The 1st Singapore– Japan Tunnel Seminar 2012, Tunnelling and Underground Construction Societyof Singapore, Singapore.
Noyaki, K., 2011. Link-line Construction to Improve Subway Network Functions－ Link-line Construction between Kotake Mukaihara and Senkawa －.
Proceedings-World Tunnel Congress2011,ITA-AITES.
Renovation & Construction Department, Tokyo Metro Co., Ltd., 2005.
Construction History of Tokyo Metro (in Japanese), Tokyo Metro Co., Ltd., Japan.

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High-raised urban expressway to mitigate
congested heavy traffic1

Yukitake SHIOI1 and Hiroshi KUDOH2
Emeritus Professor, Hachinohe Institute of Technology, Japanyshioi@blue.plaia.or.jp
2
Project Manager, Chodai, Japan

ABSTRACT
Many large cities in the developing countries are confronted with traffic heavy
congestion, negatively impacting urban functions such as residents’ daily lives
and socio-economical activities in the future. To mitigate this situation theconstruction of urban expressways is required besides the existing net of roads.
The high-raised viaduct for expressway is more advantageous than theunderground motorway in terms of enclosed space, disaster prevention,
maintenance fees, construction costs, construction period and so on. Besides, theviaduct should solve the problems of vehicle noise, urban landscape, limited
construction spaces, impact on circulation and so on. The authors propose a new
design and technology in response to these problems. The viaduct passes over theroadside trees at a height of 30~40 m with spans of 80~100 m, which has
attractive design features such as rainbows, colonnades, row of trees and so on.
The foundation can be constructed using suspended diaphragm wall machine or
the screw pile method. The piers or columns are made of reinforced concretefilled steel shell (RCFT). The superstructures are fabricated with continuous steel
box girders induced pre-stress by out-cables. This proposal enables a relatively
economical cost and short construction period to realize the high-raised viaduct.
Keywords: heavy congestion, high-raised viaduct, urban expressway, RCFT, prestressed continuous steel girder
1. INTRODUCTION
Many megacities in the developing countries are confronted with heavy traffic
congestion, damaging their urban functions. It is inevitable that residents of suchcities demand improved convenience and better living conditions in line with thedevelopment of the economy, as is the influx of people from the country sides
seeking jobs in the large cities. As a result, the capacity of existing transportation
facilities in urban area is rapidly outstripped by the growing demand forcirculation to sustain economic development and modernized lifestyles. The
heavy congestion due to the excess traffic damages the urban functions such as
residents’ daily lives, economic growth and an ongoing range of various
developing social activities.
In order to mitigate this situation an expansion of traffic facilities up to an area
ratio of 30% is required in such urban areas. However, it is very difficult toconstruct new roads or railways in the established urban districts. Location for177

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamnew traffic facilities must be found in elevated or underground spaces. In case of
motorways, some urban expressways are required besides the existing networks ofroads. For the urban expressway, the hi-raised viaducts along boulevards are moreadvantageous than the underground motorways.
Underground ways possess the disadvantages of enclosed space, risk of fire or
flooding, exhaust fumes, large daily maintenance fees, high construction costs,
long construction periods, disposal of huge amount of excavated soils and so on,
though they can offer relatively free selection of route without the demolition ofhouses. Hi-raised viaducts offer open sight distance, relatively economical
construction costs and short construction period. However, they are subject toconsideration of urban landscaping, diffusion of noise and gases from vehicles,
limited construction space and impact on circulation and so on.
The authors hereinafter explain the advantages and the technical feasibility of the
hi-raised viaduct of urban expressway in the case of the megacities in Vietnam.
2. HI-RAISED VIADUCT OF URBAN EXPRESSWAY IN VIETNAM
The streets in Hanoi and Ho Chi Minh are densely crowded with many
motorcycles, as shown in Photo 1 and Photo 2. It is forecast that the larger part ofthis motorcycle traffic will change over to cars in the future. In this case, thenumber of traffic accidents involving motorcycles may increase apart from issuesof the traffic congestion. To secure the smooth circulation and the road safety, thedevelopment of the bus networks with the dedicated bus lanes and the separationof the traffics for medium and long distance trips are necessary in urban areas.
In separating traffics for medium and long distance trips, hi-raised viaducts have
many advantages over underground motorways. Since the main streets in Hanoi
and Ho Chi Minh are wide boulevards or avenues as shown in Photo 3 and Photo4, it is possible to install the viaduct piers. It is also possible to secure unimpaired
view of the sky from the side walks, owing to the minimized sight obstruction by
the hi-raised girder of viaduct. This ameliorates the feeling of oppression causedby the low height girder. The cost and period of its construction are much better
than for underground motorways, especially on soft ground.
However, because an urban viaduct may potentially damage the quality of street
scenery, it is necessary to elevate the girder to a position of 30~40 m high and to

Photo 1: Swarm of motorcycles (1)178Photo 2: Swarm of motorcycles (2)New Technologies
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Photo 3: Boulevard in Hanoi

Photo 4: Avenue in Hanoi

design the girders and piers with attractive design features such as colonnades,
woods, rainbow and so on. The hi-raised girder over the roadside trees does not
impact the view of the people nearby and it appears as an attractive line in far
sight. It does not yield the reflection noise by the bottom face of girder from thecars passing on the lanes at the ground level. The noise and gases from thevehicles widely are widely scattered in air on the oblique fences and the people
along the viaduct feel noise and gas only slightly. Finally, the hi-raised viaducts
should be a social asset bettering the quality of the townscape.
The design and construction methods of the hi-raised viaduct in an urban area are
given below.
3. DESIGN AND CONSTRUCTION METHODS OF SUBSTRUCTURES
The authors propose a new design and technology to construct this hi-raised
viaduct along the street.
Firstly, firm foundations are required to sustain the high piers on the soft groundsof Hanoi or Ho Chi Minh. The construction of a reliable foundation is restricted ina limited space so as not to disturb the present circulation. For that purpose thesoil improvement diaphragm wall foundation (Figure 1, Photo 5, Figure 2) or thescrew pile foundation (Photo 6, Photo 7, Figure 3) are applicable as theconstruction machines capable of installing a deep foundation.
The soil improvement diaphragm wall foundation is a new type of foundation
H beamPu

Groundsurface
地表面

Steel box

Skin

Over
burden有効pressure

周面摩擦力
friction

Bearing
stratum
支持層

上載土圧

PC wallFigure 1: X type
diaphragm wall
foundation

Figure 2: Various
bone materials

H

FailureL

Steel pipe sheet
il

Steel
pile
鋼管杭

せん断
plane
すべり面

Dw

Blade
羽根

Figure 3: Bearing mechanism

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improvement machine

Photo 6: Shape of
tip of screw pile

Photo 7: Casing
Rotatorwhich consists of the soil cement diaphragm wall dug by the suspended machinein Photo 5 and with bone materials as the core of the foundation as in Figure 2. It
can reach to a depth of 50 m in a narrow working space and mobilize a large
bearing capacity with the skin friction along the surface of wall and the point
resistance of the bone materials.
The screw pile foundation is a steel pipe pile with a spiral blade welded at its
lower end as illustrated in Photo 6. Using a casing rotator (Photo 7), the screw pile
is given a vertical load and a rotating torque, and is twisted into the ground withthe wedge effect of the blade up to a depth of 50 m. The screw pile has a larger
bearing capacity than the normal steel pipe pile (Figure 3). Its bearing capacity
can be confirmed by torque substituting for an in-situ shear test.
Both types of foundation can be constructed in a limited space with little noiseand vibration and the minimum surplus soil, and without disturbance to thepassing vehicles.
The piers of the hi-raised viaduct mainly receive a major vertical load andsometimes horizontal load. Though the reinforced concrete (RC) pier requires alarge section against such major loads, the pier made of reinforced concrete-filledshell (RCFS) shown in Figure 4 can endure such loads with a relatively small
section. Reinforcing bars are very effective in keeping concrete in RCFS (Figure

Figure 5: Modelof
RCFS (RCFT)
Figure 4: Concept of RCFS pier180

Photo 8: Double
reinforcing cage toshear strain

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Figure 6: Shear stress at vertical load (left) and bending moment (right)

Photo 9: Cracks at RCFT (left) and CFT (right)

Steel pipe

Dumping ratio (%)

RCFTs

Displacement (mm)Figure 7: Deformation curves of
RCFT for moment

Figure 8: Damping ratios of RCFT
for displacement5) sound under a large load and deflection because the shear strain in RC
members caused by the vertical force and the bending moment is the maximum atthe central part of the section (Figure 6 and Photo 8) and the binding effect of theouter steel shell becomes week in cases of the larger dimensions. Furthermore, thereinforcing bars in the reinforced concrete-filled tube (RCFT) displayed excellent
ductility (Figure 7) and the restoring force characteristics of RCFT superior to theconcrete-filled tube (CFT) as shown in Photo 9, and the dumping ratio of RCFT iswarranted at 5 % as shown in Figure 8.
The piers may be designed as trees or colonnades to harmonize with the urban
landscape and the top of the piers should be Y-type in order to allow passage of a
gondola for maintenance of the superstructure (Photo 10).
4. DESIGN AND CONSTRUCTION METHODS OF SUPERSTRUCTURES
The hi-raised viaduct may be erected over the wide streets in the urban areas. To
release people nearby the feeling of eyesore or oppression from the wide
superstructure or piers, the hi-raised viaduct is effective because the highly

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for maintenanceand Y type pierPhoto 11: Hi-raised
viaduct (1)Photo 12: Hi-raised viaduct(2)

Sectional view

PC strand

Introduction ofprestress

Composite girder with PC slab

Composite girder of hi-tension steel & PC slab introduced prestressContinuous girder of hi-tension steel introduced prestress

Figure 9: Continuous and composite girders introduced prestresselevated beam is out of the sight of people nearby and the slender piers designed
beautifully supporting the long spans of viaduct are out of the care (Photo 11,
Photo 12). The viaducts visible over long sight should be designed in an attractive
manner and harmonize with the streets.
To realize the hi-raised viaduct with a long span, a new type of continuous box
girder is proposed as shown in Figure 9. The introduced prestress for continuousand composite box girders is indicated in Figure 9 and Figure 10. Figure 10
explains the process of an easily erected composite girder and introduced prestress,
with a thick prestressed concrete (PC) slab. The box girder makes reverse
deflection by the introduction of prestress to the lower flange. Therefore, the thickPC slab installed on the box girder becomes an important element of thecomposite girder. The thick slab is also durable and it enables usage of hightensile-strength steel and strong stiffness of the girder.

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Stress distribution
Erection of box girder

Hi-tension steel

Introduction of prestress to lower flange

Reverse deflection by prestress

Installation of PC slab (over 30 cm thick)Figure 10: Process of erecting composite girder with introduced prestress

The steel box girder is more advantageous in introducing prestress than the PC
girder because it is elastic without creep and drying shrinkage, and it has good
rigidity. The prestress is introduced to the girder by the out cables and realizes thespans of 90~150 m. A traveling gondola for maintenance is installed along the rail
under the box girder as shown in Photo 10 and a few dryers are set for
maintenance free inside of the box girder.
It is necessary for the designs of the box girders and the piers over the trees tomatch the street configuration and building skyline and to take consideration in
avoiding negative impact on residents’ daily lives, such disturbance due to noise,
vibration, air pollution, etc. emanating from the traffic lanes on the viaduct. To
connect the viaduct with the existing road network smoothly, some rational

Photo 13: Example of interchange

Photo 14: Example of junction

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Vietnaminterchanges (Photo 13) and junctions (Photo 14) should be disposed in theimportant points.
These concepts are applicable to the megacities in other developing countries
besides Vietnam.
5. SUMMARIES
1. Since, in line with the rapid development of economy, many megacities in thedeveloping countries are confronted with heavy traffic congestion which
adversely impacts the urban functions, the expansion of traffic facilities isrequired in the urban area to mitigate this situation.
2. The hi-raised expressway viaduct is more advantageous than the undergroundmotor way from many viewpoints.
3. The construction of the hi-raised viaduct can be realized with economical costand short period but its several problem points in relation to the surrounding
urban area are to be resolved by the design so as to adverse impacts on
residents’ daily lives.
4. As the foundation of the hi-raised viaduct, the soil improvement diaphragmwall foundation and the screw pile foundation are recommended in viewpointof reliable bearing capacity, easy construction in a limited space, less pollution,
little disturbance to the passing vehicles and so on.
5. As the pier of the hi-raised viaduct, the reinforced concrete-filled shell (RCFS)
is proposed from the viewpoints of major load-carrying capacity, large
ductility to vertical load and moment, superior restoring force characteristics
and constant value of damping ratio.
6. As the superstructure of the hi-raised viaduct, the continuous and thecomposite box girders with introduced prestress, with a thick prestressed
concrete (PC) slab, is devised to realize long spans, strong stiffness, use ofhigh quality steel, and long durability with a gondola for maintenance anddryers inside.
7. The viaduct composed of box girders and high piers shall be attractively
designed to match the street configuration and needs rational interchanges andjunctions near the important points.
8. The concept discussed here is applicable to the megacities in other developing
countries besides Vietnam.
AKCNOWLEDGEMENT
The authors would like to express their deep gratitude to Messrs. Kiyosi Matsui
and Narutoshi Okabe for their cooperation in producing some perspectives of the
hi-raised viaduct and Dr. Akira Ohwada who provided materials on screw pilemethod. Furthermore, the authors would also like to offer their thanks to Prof.
Akira Hasegawa who is a co-researcher on RCFT and Dr. Phan Le Binh whooffered some pictures of the streets in Hanoi.

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Application of water screen
fire prevention systems
Hideaki KUWANA1,
Reiko AMANO , Takuzo IDA , Osamu IMAZEKI4,
Toshihide TSUJI5
1
Senior Research Engineer, Technical Research Institute, Kajima Co., Japankuwana-hideaki@kajima.com
2-4
Kajima Co., Japan
5
Hochiki Co., Japan2

3

ABSTRACTThis study originally aims at understanding the characteristics of water screen
systems as one part of the various technologies used in the construction of fire
safety systems for structures in deep underground tunnels. The water screen(hereafter referred to as WS) aims at restraining the spread of the heat and smoke
generated by fires to other compartments or reducing the speed of their spread aswell as controlling the heat release rate during fires in tunnels. Furthermore, theobjects of this study are to reduce heat radiation generated from the origin of afire and to support evacuation and activities for firefighting and rescue utilizing
the transparency of water. The WS system has been applied to buildings and civilengineering structures. Several applications are described.
Keywords: Water Screen, application, fire prevention, evacuation, heat flux, fire
safety engineering, performance design
1. INTRODUCTION
When fires break out in closed tubular spaces such as tunnels or subway
stations where air inflows are restricted, heat, smoke and toxic compounds such ascarbon monoxide spread throughout the entire spaces. As a result, activities forevacuation, rescue and fire-fighting are retarded by the fires naturally expanding
to nonflammable materials.
This study aims at understanding the characteristics of the WS systems as one
part of the various technologies used in the construction of fire safety systems fortunnels, offices, stations, etc. The WS aims at restraining the spread of the heatand smoke generated by fires to other compartments or reducing the speed of theirspread as well as controlling the heat release rate during fires in compartment. The
objects of this study are to reduce heat flux generated from the origin of a fire andto support evacuation and activities for firefighting and rescue utilizing the sight
through property of water.
Carrying out of plenty of fire experiments at the Miyagi fire prevention test
center of Hochiki Corporation using a 1/2 scaled tunnel model (height 2.7m,
width 5.4m, length 43.7m) equipped with the WS assuming a fire for a passenger
car has verified the effectiveness of the WS system.
Various fire experiments have resulted in clarifying the high effectiveness ofthe WS system on the reduction of heat and smoke. In 2000, Kajima Corporation

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October
2013, 2013,
Hanoi,Hanoi,
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Vietnamcarried forward the technical development with regard to“compartment technology for fire zones using water
droplets screen=Water Screen System” as a Kajima’s
original technology and in 2001 this WS system was
authorized first in Japan by the Minister of Land,
Infrastructure, Transport and Tourism (MLIT) based on
the performance evaluation as a special fire prevention
equipment in the architectural field.
The WS is a system that creates screens of water byspraying water from spiral nozzles (Fig.1) arranged inlines in compartmented positions. This fire prevention
Fig.1
system creates the compartments that can restrict theSpiralnozzledamage of structures to limited areas and support
firefighting activities as well as securing the evacuation safety for victims by
restraining the spread of heat and smoke and washing out toxic floating particles.
2. PERFORMANCE TESTSThe outline of the tests carried out in 2003 is briefly shown below.
1. Test model (Fig.2): A tunnel space with a section of 2.7m height×5.4m width,
43.7m long.
2. WS equipment: WS pressure 1.0(MPa), average particle diameter 200(µm),
water amount 10(Liter/min/nozzle), water spray angle 150 – 170(degrees).
3. Blower equipment: 20 fans installed at the position 2m away from the modelend on the air supply side.
4. Measurement details: The heat release rate was obtained using the oxygen
consumption law and weight conversion law. In order to understand theeffectiveness of the WS in washing out soot generated during fires, the behaviorof soot in smoke at high temperatures was studied using a duct installed at the endof the opening of the model. Furthermore, for the purpose of understanding theburning behavior of the fire source, the spray behavior of the WS and flow
behavior of the smoke as well as investigating the fire source and evacuation
directions during evacuation and fire fighting, observations were carried out using
video cameras and thermo-cameras.
5. Test conditions: Test factors were set as ① Wind speed (0.0, 1.4, 1.8, 2.2(m/sec), ② Fuel (n-heptane, gasoline), ③ The heat release rate (1.5, 5.0 (MW)),④ Activation of WS equipment. On thebasis of the Froude Law underconsideration of the reduced scale ratio
as a similitude ratio, the heat release
rate was set at 1.5(MW) on theassumption that a single automobile
burnt. The standard value for the windvelocity which prevents the heat flux
from reversing flow on the windwardside during a fire under the conditionsof having a natural ventilation or a
Fig.2 Test model
longitudinal ventilation method was set
to be 1.4(m/sec).

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2.1 Test Results
Tests were carried out in 22 cases by combining test factors. And to report thistime, test results are described in cases of [Wind Speed=0.0(m/sec), Fuel=gasoline,
Heat release rate=1.5(MW), Case 1=without WS, Case 2= with WS].
2.1.1 Effects on received radiation calorie
Fig.3 shows the time history of the received radiation calorie measured using aradiometer installed on the outside of the model opening. The received radiation
calorie in Case 1 (without WS) reached about 120 – 140(W/m2), in Case 2 (withWS) was about 5(W/m2). It is indicated that the received radiation ratio becomes
small due to the activation of WS.

2000

160

発熱速度
[KW] [kW]Heat release
Rate

1800

140

1600

120

Case 1Case 2

100
80

1400

Case 1Case 2

1200
1000

200
720

660

600

540

480

420

time[sec]
[sec]
Time

Fig.3 Radiation receiving calorie

Fig.4 Heat release rate

CO2 [%]CO [ppm]

2.1.3 Effects on gas concentration
Fig.5 shows the time history of CO
gas concentration and CO2 gas
concentration. In Case 2, not only theeffects of the decrease in the heatrelease rate upon the restraint of theamount of gas generated, but also thegentle decrease in the latter half period
after fire extinguishment were shown.
The cause was that the gas confined in
the compartments gradually flowed out.

360

0time[sec]
[sec]
Time

300

0
240

0

400

180

20

600

120

40

800

60

60

0
60
120
180
240
300
360
420
480
540
600
660
720

Radiation receiving
calorie [W/m2]
放射受熱量 [W/m2]

2.1.2 Effects on heat release rate
Fig.4 shows the time history of the heat release rate. In Case 1, the heat release
rate attained a maximum value of 1.5(MW). In Case 2, it was 1.0(MW). In bothcases, we have put the same amount of fuel. It can be assumed that the value forthe heat release rate became small because of the restraining effect which was
produced by the retardation of combustion due to the compartments created by the
WS and water particles.

Time [sec]Fig.5 Gas concentration
Application ofwater screen
fire prevention
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prevention system

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3. ACQUISITION OF GENERAL AUTHORIZATION
The WS system acquired general authorization as a piece of designated fire
preventive equipment in 2005 based on the results obtained from the performance
tests.
The designated fire preventive equipment is a piece of fire prevention
equipment prescribed in Article 112 of the Building Standards Law Enforcement
Order. It must be built ① using the construction methods prescribed by the MLITor must be ② authorized by the MLIT, under the condition that caloric heat
induced by an ordinary fire will never produce flame on any surfaces except thesurface of the fire origin within one hour after the heating begins.
3.1 Outline of General Authorization
With regard to the prescribed value forthe performance evaluation of special fire
prevention equipment, in the case of a fire
resistance furnace being heated over one hour,the maximum temperature and averagetemperature of an unexposed surface (themaximum temperature in the furnace is945℃) are required to be 200℃ or less and
160℃ or less respectively.
Fig.6 shows the conditions when theheating begins in the furnace and Fig.7 shows
the conditions when the WS are activated 20
minutes after the heating begins.
It was confirmed from the test results thatthe maximum temperature was 156℃ and theaverage temperature was 77℃ in the case of
one line arrangement. As the result ofconfirming that these values from the tests
were below the prescribed values, the generalauthorization was obtained (Fig.8).

Fig.7 Conditions during heating ina furnace (WS activated)Since
obtainingthegeneralauthorization, the WS system has been
applied to buildings and civil engineering
structures.
Several applications are described below.

1000

Temperature [℃]
Temperature[℃]

4. APPLICATIONS

4.1 Rental Office Building

Fig.6 Conditions when heating
begins in a furnace (WS not
activated)

In Furnace

600
WS start and stop

400

Unexposed Side

200
0

The WS system was applied to thelocation connecting the 1st basement andthe subway concourse for an office building

188

800

0

5

10

15

20

Time[min]
[min]
Time

25

30

Fig.8 Time history of
Temperature

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completed in Oct. 2005. This place where many unspecified people pass throughwas assumed to be a closed space when shutters were pulled down.
It can be seen that the area opposite to the compartment partitioned by the WS
is open to the outside. The WS compartment is composed of a height of 4.0m,
width of 5.6m and 19 spiral nozzles. Fig.9 shows the entire building to which the
WS system is applied and Fig.10 shows the conditions when people pass throughin the case of the WS being activated.

SteelshutterWS

Fig.9 WS system is Right side

Fig.10 WS activated

4.2 Office Building for a Construction Equipment Manufacturing Plant
The WS was applied to the compartment between the central atrium and thecorridor of the administration building of a construction equipment manufacturing
plant. The safety in relation to the spread of smoke in this space was confirmed
using the whole building evacuation safety verification method (=performance
design).
Before completion of the building, tests were carried out in order to confirm
the actual activation conditions of the WS. About 50 people concerned in thejurisdiction fire station and architectural guiding section who participated in thetests confirmed that all the fire victims, including the injured, could easily passthrough the compartment by observing the formation of the WS as a compartment
or having actual experience of passing through. Fig.11 shows the conditions for
those passing through, in the case of the WS being activated. Fig.12 shows thecompartment line is indicated with the curved lines not straight one.

Fig.11 Conditions for those passing
through in the case of WS activated

Application ofwater screen
fire prevention
Applicationof waterscreen firesystems
prevention system

Fig.12 Compartment Line
indicated with curves

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4.3 Utility Shield Tunnel (Demolition work for shield machines)
With regard to the demolition of shield machines after completion of shield
excavation work, a method for removing machines that have been broken into
small pieces using gas cutting equipment and then lifting the pieces throughaboveground openings made for the vertical opening where the machine reaches
is mainly used. Before conducting operations using flames generated by gas
cutting equipment, oil in the machines is extracted and grease is mostly wiped off.
The oil, however, cannot be completely removed beforehand. Due to this, sparks
induced by the gas cutting equipment set fire to residual lubricant during
demolition work and a large amount of smoke, which is blackish with soot inmost cases, is generated.
As for the above mentioned problems, demolition work has been simplified
while exhausting the smoke by using dust collectors. However, it has been fearedthat the working environment deteriorates due to smoke permeating the wholetunnel and that smoke rising up to the above ground has bad effects upon the
peripheral environment.
Accordingly, the WS equipment should be installed both in the front and rearof the shield machine for decreasing smoke generated from the demolition work.
Fig.13 shows the conditions on the inside of the tunnel and Fig.14 shows theactivation conditions of WS on the vertical opening side where the machinereaches. The smoke concentration decreased by 80% due to the WS. Answers to
the questionnaires given after the demolition work such as “Odor of burning andsmoking decreased” or “The amount of smoke rising from an opening above
ground decreased” were obtained.

Fig.13 Inside of shield machine
before demolition

Fig.14 WS Activated

4.4 Subway Station Platform
4.4.1 Fire Prevention for Station Buildings
In February of 2003, a major accident with 192 dead and 148 injured resulted
from an incendiary fire in a subway train in Daegu, Korea. Most casualties wereconfined to the train, but some passengers were killed in front of fire prevention
shutters because they had lost their directions of escape in the black smoke. Basedon this major accident, the Railway Bureau of the MLIT revised “The ministerial

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ordinance establishing technological standards with regard to railways” and “Thestandards for interpreting this ministerial ordinance” and notified the parties
concerned with new standards for the prescribed improvement of noncombustible
passenger car, fire safety of station yards and evacuation safety.
4.4.2 Process of WS Installation
The space of ceilings for the existing stations is too limited to install fire
prevention shutters. Moreover, it is assumed that a number of people would gather
in front of stairways during evacuation from fires. The WS equipment was
installed in front of the central stairs connecting the platform stairs and the ticket
gate stairs. In March, 2009, the WS equipment tests were carried out in thepresence of staff of the authorities concerned. Fig.15 shows the activation
conditions of WS.
4.4.3 Evacuation Efficiency
The evacuation calculation is carried out under the condition that the effective
movement coefficient at the opening part is 1.5[persons/m/sec]. The number of
persons passing through per hour can be increased by widening the effective
width of the opening part. Although the effective width of a fire door or a side
door is about 0.9m, the effective width for the WS equipment can be set to be up
to 50m owing to the general authorization. (Fig.16 shows)Due to the fact that the compartments can be created using only water, theopposite side can be clearly seen and evacuees can move forward while
confirming the conditions in the stairways.

1.6m+opposite 1.6m
=3.2m
Fig.15 WS ActivatedFig.16 Availability width

4.5 Furniture Factory
The Furniture Factory is connected by a bridge from assembles building toother buildings. The designated fire preventive equipment with WS to be installed
to the opening (Area compartment as Article 112, the Building Standard Law
Enforcement Order) challenge heat insulation property required for thecompartmentation. There is a rail conveyor hanging on to pass through the
opening.
The heat insulation property in the opening that the through section can be
sufficiently exhibited is the outstanding features of WS, but this time, things havebeen proven in the practice of the CFD analysis in specific cases.

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fire prevention
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calculation result from CFD. The heat release rate has given 0.113t2 (t<=163(sec)),
3000(kW) (t>163(sec)) in fire sources. Both edges of these areas are freeboundary. When WS system activated, the maximum temperature is 88℃. Fig.18
shows that WS nozzles are installed. Fig.19 shows activation conditions of WS.
(Imazeki, 2005)
800

Upper Area

4500

Rail Conveyor
4500

WS nozzles
Fire Sources
6000
[mm]

WS

Lower Area

3200

Fig.17 Calculation model

6800

Table.1 CFD Calculation Result (Temperature)
Upper area fromWS nozzles
Lower area fromWS nozzles
Total area

Average
Maximum
Average
Maximum
Average
Maximum

WS not activated
58.6
194.0
106.7
171.5
84.8
194.0

WS activated
63.3
88.0
39.0
39.4
50.1
88.0

WS

Fig.18 Installed WS nozzles

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Fig.19 WS Activated

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5. CONCLUSION
It was also confirmed that the occupants could survive in the fire zone
partitioned by using the WS and that activities for refuge and fire-fighting could
be effectively carried out. As a result, the WS as partitioning technology for a fireis very useful.
The WS has won the award of two major in Japan.
1. Association of Building Engineering and Equipment,
Environmental and Equipment Design Award 2007, category 1(Mechanical and Electrical Equipment/System Design) Best
Design Award
2. Architectural Institute of Japan, the Prize of Architectural
Institute of Japan 2011, Building Engineering Division AwardREFFERENCES
R.Amano, Y.Izushi, H.Kurioka, H.Kuwana, T.Tsuruda, T.Suzuki, Y.Ogawa,2004.01, Water Screen Fire Disaster Prevention System -Characteristics of Water
Screen as Partitioning Technology-, ICUS/INCEDE Report 2, New Technologies
for Urban Safety of Mega Cities in Asia, Agra, India
R.Amano, Y.Izushi, H.Kurioka, H.Sato, H.Kuwana, T.Tsuruda, Y.Ogawa,T.Suzuki, 2004.03, Water Screen Fire Disaster Prevention System in
Underground Space, Proceedings of the 6th Asia-Oceania Symposium on Fire
Safety and Technology, Daegu, Korea
Imazeki O., Kurioka H., Oka Y., Takigawa S., Amano R. , 2005.09,
Computational Fluid Dynamics of Hot Current from a Fire Source near a Tunnel
wall, 8th The International Association for Fire Safety Science Symposium,
Beijing, China
Amano R., Kurioka H., Imazeki O. , 2005.10, Computational Fluid Dynamics
Simulation of Thermal Behavior under Working Water Screens in a Tunnel, the
4th International Symposium on New Technologies for Urban Safety of Mega
Cities in Asia, Nanyang Technological University, Singapore
Amano R., Izushi Y., Kurioka H., Kuwana H., Tsuruda T., Suzuki T., Ogawa Y. ,2006.03, Prevention Measures against Fires in Road Tunnels and Water Screen
Fire Prevention System, The International Symposium on Management Systems
for Disaster Prevention, Kouchi, Japan
Amano R., Kurioka H., Kuwana H., Murakami M., Tsuruda T., Suzuki T., Ogawa
Y. , 2006.05, Applicability of Water Screen Fire Disaster Prevention System toRoad Tunnels in Japan, 3rd International Conference Tunnel Safety andVentilation -New Developments in Tunnel Safety, Graz, Austria
H.Kuwana, H.Kurioka, R.Amano, Y.Izushi, T.Tsuruda, T.Suzuki, Y.OGAWA，2006.07, Effects of Water Screen system in compartments, 12th International
Conference on Aerodynamics and Ventilation of Vehicle Tunnels, Portoroz,
Slovenia
Application ofwater screen
fire prevention
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Evaluation of applicability of steel pipe piles
in Vietnam
Shunsuke USAMI1, Dinh Van THUAT2, Yasushi WAKIYA3,
Eiji KATAYAMA4 and Dinh Van HIEP5
1

Senior researcher, Civil Engineering Research Department, JFE SteelCorporation, Japan;s-usami@jfe-steel.co.jp
2
Asst. Prof., Department of Steel Structures, National University of Civil
Engineering, Vietnam
3
Deputy General Manager, JFE Steel Vietnam Co., Ltd., Japan
4
Construction Materials & Business Development Department, JFE SteelCorporation, Japan
5
Asst. Prof., IPTE Director, National University of Civil Engineering, Vietnam
ABSTRACTIn Vietnam, many infrastructure development projects (e.g., bridges, expressways,
port facilities and high-rise buildings) are ongoing now and rapidity, safety andenvironmental considerations are required for their constructions. These
structures are often constructed on the soft surface ground. Therefore, pilefoundations need to be used in order to support superstructures. Bored piles andprestressed concrete spun piles are commonly used as pile foundations, while theapplication of steel pipe piles is not popular yet due to some causes such as thehigh material cost. However, steel pipe pile has merits such as a high material
quality, high strength, easy handling and rapid construction. Therefore, steel pipe
pile can be an effective and safe solution for construction of new infrastructure
projects. In addition, a standard for design of steel pipe piles has not been
completely regulated in Vietnam. In this paper, the applicability of steel pipe piles
for bridge and high-rise building foundations is examined. The trial design ofsteel pipe piles and bored piles is carried out and competitiveness of applying
steel pipe piles is clarified. The Vietnamese and Japanese design formulas areapplied to steel pipe piles. Bearing capacities obtained from the two formulas arecompared and their difference is found. In conclusion, the authors suggest adesign method of steel pipe piles in Vietnam.
Keywords: steel pipe pile, bored pile, design standard, bearing capacity
1. INTRODUCTION
In Vietnam, a high economic growth is expected in medium and long terms andthe infrastructure development is declared as one of high priority policy issues.
Curently, some big infrastructure projects such as Nhat Tan Bridge, Lach Huyen
Port and Cai Mep - Thi Vai Port are ongoing and there are many other plans
required to improve the country’s infrastructures in future. The rapidity, safety,

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Vietnamcost and environmental considerations are required in the construction of
infrastructures and ground condition is one of the important examination issues. In
Vietnam, the soft soil ground often widely spreads on the surface layer. Therefore,
deep pile foundations need to be used in order to support superstructures. There
are various types of pile foundations as shown in Figure 1 and the features ofthese pile foundations are given in Table 1. Steel pipe piles have a high quality
and high strength compared to concrete bored and spun piles. Steel pipe piles also
have a large bearing capacity against axial loads and a large horizontal resistanceagainst horizontal forces such as due to seismic and wind loads.

(a) Steel pipe pile(b) Concrete bored pile(c) Concrete spun pile
Figure 1: Types of pile foundations
Table 1: Features of pile foundations

Items
Material
strength
Bearing
capacity
Corrosion
Construction
speed
Reliability of
construction
Environmental
impactSteel pipe pile
-High reliable-High ductility-High compression
stress-High tensile stress

Bored pile
-Brittleness

Large

Large

Average

Fair

LittleLittleRapid

Low

AverageGood
Little soil removal

Spun pile-Brittleness-High compression -High compression
stressstress-Low tensile stress -Low tensile stress

Fair (collapse of
Fair
excavation hole)
So much soil
Little soil removal
removalAs for the construction, a construction machine of steel pipe piles is compact.
Steel pipe piles can be rapidly driven because some construction procedures suchas excavation hole and concrete curing as required for bored piles are not needed.
In addition, steel pipe piles are easily handled during transportation andconstruction because of their light weights. Therefore, steel pipe piles have beenrecognized as an effective and safe solution for construction in many countries
such as Japan. However, the construction technology of steel pipe piles is still
new in Vietnam and as a result the application of steel pipe piles is rare.
Furthermore, the design standard has not been completely regulated. Therefore,

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the purpose of this paper is to evaluate the applicability and suggest a design
method of steel pipe piles in Vietnam.
2. DESIGN OF STEEL PIPE PILES
The design of steel pipe pile foundations requires considerations of geotechnicaland structural capacity, stresses in pile and displacement. There are various
calculation methods depending on the country’s standard/specification. In
particular, the authors focus on the calculation methods of the geotechnical andstructural capacity of steel pipe piles in Vietnam and Japan in this paper.
2.1 Design standard/specification
Table 2 summarizes the standard/specification/manual used in the design of steel
pipe piles in Vietnam and Japan. In Vietnam, the specification 22TCN272-05
which was compiled based on the AASHTO LRFD 1998 has been applied tobridge design and the construction method of driven piles has been mentioned.
The standard TCXDVN 205-1998 has still been limited in calculation of the
bearing capacity of steel pipe piles. The book “Pile foundation analysis anddesign” compiled by Professor Vu Cong Ngu published in 2006 is only areference design manual. In Japan, the design method of steel pipe piles has
already been established and followed the allowable stress design (ASD) approach.
The “Specifications for Highway Bridges” for bridge foundations and“Recommendations for Design of Building Foundations” for building foundations
are generally used and updated as necessary.
Table 2: Standard/specification/manual for the design of steel pipe piles
Country

Title

Field

Designapproach

22TCN272-05 “Specification for bridge
Bridges
LRFD
design”, Section 10.7 Driven pile
TCXD 205-1998 “Pile foundation Vietnam
Specifications for design”
Book “Pile foundation analysis and
ASD
design” by Prof. Vu Cong Ngu“Specifications for highway bridges”,
Bridges
ASD
Chapter 12: Design of pile foundations
Japan“Recommendations for design of
Buildings ASD
building foundations”
Notes: ASD: Allowable stress design, LRFD: Load and resistance factor design
2.2 Bearing capacity of groundThe bearing capacity of ground includes the end bearing resistance and shaft
friction resistance as given by Equation 1. Allowable bearing capacity in ASD andthe factored bearing resistance in LRFD are taken as Equations 2 and 3,
Evaluation ofEvaluation
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Vietnamof applicability
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Vietnamrespectively. Table 3 summarizes the resistance factor (φ) used in 22TCN207-05
and safety factor (SF) in the Schmertmann SPT and Japanese methods. Moreover,the unit end resistance and unit shaft friction resistance for building and bridgefoundations are shown in Tables 4 and 5 and Tables 6 and 7, respectively.

ASD:
LRFD:

Qu  Q p  Q f  q p Ap  q f Af(1)

Qa  Qu / SF
QR   pQ p   f Q f   p q p Ap   f q f Af

(2)
(3)

where Qu is the ultimate bearing capacity of ground; Qa is the allowable bearing
capacity of ground; Qp is the end resistance; Qf is the shaft friction resistance; qp
is the unit end resistance; qf is the unit shaft friction resistance; φp, φf are theresistance factors; Ap is the cross sectional area of pile; Af is the surface area ofpile and SF is the safety factor.
Table 3: Resistance factor (φ) in 22TCN207-05 and safety factor (SF) in
Schmertmann SPT method and Japanese method
Vietnam
SPT method(22TCN207-05)
φ
SPT: 0.45
Sand
CPT: 0.65
End
resistance Clay 0.70
Rock 0.50
SPT: 0.45
Sand
CPT: 0.65
Shaft
friction
α method: 0.70
resistance Clay β method: 0.50
γ method: 0.55
Formula198

QR = φpQp + φfQf

Schmertmann
SPT method
SF

Japan

SF
Bridge3(Ordinary)
2(Seismic)

Building
3(Ordinary)
1.5(Seismic)

2

3(Ordinary)
2(Seismic)

3(Ordinary)
1.5(Seismic)

Qa=(Qp/2+Qf)/2

Qa = (Qp+Qf)/SF

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Table 4: Unit shaft friction resistance, qf (kN/m2)

Sand

VietnamJapanusing Schmertmann
SPT method
10/3N
5.55+14.56 lnN60

Soft limestone, shelly sand

1.72+12.83 lnN60(≦100)

Clay

18.58+20.93 lnN60

1/2qu

Mixed clay, powdery fine sand23.27+14.07 lnN60(≦100)

Soil types

Note: N60 is the SPT N value corrected for field procedures
Table 5: Unit end resistance, qp (kN/m2)
Soil types
Sand
Soft limestone, shelly sand
Clay
Mixed clay, powdery fine sandVietnamJapanusing Schmertmann
SPT method
46N60
300N
92N60
126N60(≦18,000)
184N60

Table 6: Unit shaft friction resistance, qf (kN/m2)
Soil
types

Vietnam
SPT method(22TCN207-05)－

Sand0.0019Nfor driven displacement piles

Schmertmannmethod
5.55+14.56 lnN60
for sandJapan
2N

1.72+12.83 lnN60(≦100)
for soft limestone, shelly
sand
18.58+20.93 lnN60
for clay

Clay

SPT

C or 10N

23.27+14.07 lnN60(≦150)
for mixed clay, powdery
fine sand－－Note: N is the average SPT blow count along the pile shaft
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Table 7: Unit end resistance, qp (kN/m2)
Soil
types

Sand

Clay

Vietnam
SPT method(22TCN207-05)
0.038Ncorr (Db/D)<0.4Ncorr for sand
<0.3Ncorr for nonplastic silts
1.92
N corr  0.77 log10 (
)N
σv '

Japan

Schmertmann
SPT
method46N60
for sand
92N60
300N
for soft limestone, shelly
sand*Db/D≧5
126N60for clay
184N60－for mixed clay, powdery
fine sandNote: Db is the embedment depth into the bearing layer

2.3 Structural capacity of piles

When the structural capacity of steel pipe pile is calculated in Vietnam, it needs torefer to relevant specifications in foreign countries because the calculation
formula has not been regulated adequately. Therefore, the authors refer to theJapanese manual and AASHTO ASD and evaluate the structural capacity of steel
pipe piles by using allowable stress design approach. The allowable structural
capacity can be given by Equation 4.
p    A    Fy  A(4)where P is the allowable structural capacity, σ is the allowable stress in piles, φ is
the reduction factor, Fy is the yield strength of steel and A is the cross sectional
area of pile.
The structural capacity of steel pipe pile is reduced from an ultimate value to anallowable value by a reduction factor. Table 8 summarizes the reduction factor
used in the Japanese method and AASHTO ASD. The reduction factor used inJapan is determined in consideration of the effect of local buckling based on the
results of compressive tests for short steel pipes. In contrast, the reduction factor
in the AASHTO ASD accounts for uncertainty in resistance and applied load suchas the effects of driving stress levels, eccentricity of applied load, damage to piles
due to driving and inherent variability in pile material. The reduction factor in theJapanese method is about twice larger than that in the AASHTO ASD and thismeans that the AASHTO ASD is much more conservative than the Japanesemethod. Therefore, it is recommended that the Japanese method is applied to thecalculation of the structural capacity of pile when an economical design isrequired.

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Table 8: Reduction factors in the Japanese method and AASHTO ASD
Japan

t(0.8  2.5 )r

1 .0

Equation

Valuet: 0.01  ≦ 0.08
rt
: ≧ 0.08r

AASHTO ASD(φ)( ecc )( HDF )LF

where:
t: Thickness of steel piper: Radius of steel pipe

where:
φ: Product manufacturing
variability
ecc: Load eccentricity factor*SF = 1.5 is considered in the HDF: Hidden defect factor due
calculation of allowable stress of to damage during pile driving
steel pipe pile.
LF: Load factor
Driving damage likely: 0.25
0.55～0.67
Driving damage unlikely: 0.33

3. TRIAL DESIGNSThe trial design of steel pipe piles and bored piles is examined for bridge andhigh-rise building foundations in order to evaluate the applicability and suggest adesign method of steel pipe piles in Vietnam. Further details can be found in the
research report by JFE-IPTE/NUCE in 2012.
3.1 Design of steel pipe piles for building foundations

The trial design is examined for three typical types of 35-story buildings with 3
basements, including reinforced concrete (RC) building, steel building and hybrid
building (Figure 2). These buildings are assumed to be constructed in Hanoi anddesigned in accordance with the Vietnamese standards. A typical groundcondition in the Hanoi area as shown in Figure 3 is used as the site condition. The
piles are embedded into the gravel layer. The center pile cap and the surrounding
pile cap are subjected to axial forces of about 13,300 tons and 1,600 ~ 2,500 tons,
respectively. The bearing capacity of bored piles is calculated using the Japanese
formula and Meyehof’s formula specified in the TCXD 205-1998 while thebearing capacity of steel pipe piles is calculated using the Schmertmann SPT
method and Japanese formula. Table 9 summarizes the obtained design results.

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Vietnam(a) Structural model(b) Plan of pile caps

Figure 2: Structure model and plan for pile caps
Layer
Thicknes
s
1.1

Depth

7.4

8.5

1.1

Data

Soil classification
Surface fill soil

0
5

0
4

Sandy clay

7
9
7
6

6
8
6
5

6

5

7
9

6
8

11
13
17

9
11
14

24
26

20

25

21

25
30

21
25

32

27

39

33

70
70

58
58

100

60

Sandy clay
6.7

15.2
Sandy clay

5.6
4.5

20.8
25.3

Fine sandMedium sand

15.3
4.6

40.6
45.2

GravelGravel and rock9.8

N value N60 value

0

10

20

30

SPT chart
40

50

60

70

80

90 100

0

10

20

22
30

40

L=43.6m
50

55.0

Figure 3: Site condition in Hanoi area

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Table 9: Design results of bored and steel pipe pilesa) 35-story steel buildings

Dimensions
LengthNumber of piles
Bearing capacity
Structural capacity

mm
m
kN
kN

Bored pile
TCXD
2051998
D1200
43.6
72
8500.09160.0

Steel pipe pile
Schmertmann
SPT method
D1200×t30
43.6
728500.09024.5

Japanese
formulaD1100×t14, 15
43.6
36
36
9182.98249.1 8922.5

Bored pile
TCXD
2051998
D1200
43.6
120
8500.09160.0

Steel pipe pile
Schmertmann
SPT method
D1200×t30
43.6
1208500.09024.5

Japanese
formulaD1100×t14, 15
43.6
80
36
9182.98249.1 8922.5

Bored pile
TCXD
2051998
D1200
43.6
86
8500.09160.0

Steel pipe pile
Schmertmann
SPT method
D1200×t30
43.6
868500.09024.5

Japanese
formulaD1200×t14, 15
43.6
12
56
10583.2
8957.6 9685.6b) 35-story RC buildings

Dimensions
LengthNumber of piles
Bearing capacity
Structural capacity

mm
m
kN
kN

c) 35-story hybrid buildings

Dimensions
LengthNumber of piles
Bearing capacity
Structural capacity

mm
m
kN
kN

3.2 Design of steel pipe piles for bridge foundations

The bridge structure comprises of six simple spans with I-shaped girders(A1~P1~P2 and P8~P11~A2) and six continuous spans (P2~P8) with composite
pre-stressed RC girders (Figure 4). The total length of the bridge structure is 855.9
m. The pile foundations are calculated for the pier P3 and the load combinations
are shown in Table 10. A typical ground condition in the Hanoi area is shown in
Figure 5 as the site condition. The piles are embedded into the gravel layer. The
bearing capacity of bored piles is calculated using the Japanese formula andMeyehof’s formula specified in the TCXD 205-1998 and that of steel pipe piles iscalculated using the SPT method specified in 22TCN207-05, Schmertmann SPT
method and Japanese formula.

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The bending moment and axial force generated at the top of pile is calculated byusing an analysis software. Table 11 summarizes the design results. The diameterof steel pipe piles by the Japanese method is about two-third compared to those ofbored piles and steel pipe piles by the 22TCN207-05 and Schmertmann SPT
method while remaining the same bearing capacities. The diameter and thicknessof steel pipe piles by the Japanese method can be reduced compared to theVietnamese method since there is about ten times of difference in the bending
moment generated at the top of piles as shown in Table 11. The difference in anassumption of the stiffness of footing between Japanese and Vietnamese method
is one of the reasons and the further investigation is required.

Figure 4: Bridge structure (A1, P1~P4)
Elevation
(m)

(m)

Layer
Thicknes
(m)

10.5

4.6

4.6

5.5

-0.8

-6.1

Depth

9.6

15.9

21.2

5.0

6.3

5.3

Data

Soil classification

33.6

Clay, yellowish grey, lightgrey
very stiff

9

13

10

Sandy clay, brownish grey
medium stiff

4

3

5

4

Clay, yellowish grey, lightgrey
very stiff

16

12

21

15

22

16

9

6

7

5

9

6

32
30
34

24
22

45

33

41

30

53

39

73

54

75

56

78

58

Sandy clay, greenish grey
very stiff

12.4

45.6

12.0

10

20

30

40

50

60

70

80

90 100012Gravel, cobble with coarse
sand, saturated
very dense-30.5

SPT chart
0

Gravel sand, saturated
dense to very dense-18.5

N value N60 value

5

10

15

20

25

25
30

35

40

45

L=40.0m

Figure 5: Site condition in Hanoi area

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Table 10: Load combination at bottom footing and axial load
Vertical
load
N
(kN)

Service I(Longitudinal wind 71,880
load - LWL)
Strength I(LWL- 94,426
Longitudinal)
Extreme event(Earthquake
88,583Longitudinal - LWL)

Horizontal load
Hx
(kN)

My
(kNm)

3,292

57,8583,293

59,057

11,509195,714

Table 11: Design results

Diameter
Length
Bending moment
Axial force
Bearing capacity

Bored pile
Reese&O’neillmm φ1500m
40.0
kNm 6331.0
kN10050.0kN
23698.6

Diameter
Length
Bending moment
Axial force
Bearing capacity

Steel pipe pile
Using SPT
22TCN207-05
mm φ1500×t28
m
40.0
kNm 6322.0
kN
9185.5kN
7935.0Reese&WrightMeyerhof

13583.97667.9Schmertmann
SPT method

Japanese
methodφ1000×t14
40.0
543.4
8708.210291.99496.0

4. CONCLUSIONSThis study has examined the applicability of steel pipe piles for bridge and highrise building foundations in Vietnam by means of trial designs. The conclusions
and recommendations for the application of steel pipe piles and further studies are
as follows.
(1) The 22TCN272-05 specification has been applied to design bridge and driven
piles can be designed in accordance with this specification in Vietnam. On theother hand, the design specification of steel pipe piles for high-rise building
foundations has not been regulated.

Evaluation ofEvaluation
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Vietnamof applicability
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October
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Vietnam0ctober
Vietnam(2) The diameter of steel pipe piles obtained by using the Japanese formula can beequal to or smaller than that of bored piles while remaining the same bearing
capacity as that of bored piles.
(3) As for the calculation of structural capacity of piles, the diameter andthickness of steel pipe pile can be reduced by using the Japanese formula since
the reduction factor in the calculation of allowable stress in piles is different.
(4) It is recommended that the design specification of steel pipe piles subjected toboth axial forces and bending moments can be developed in Vietnam based on
the Japanese specification with consideration of constructional and material
conditions.
REFERENCES

22TCN272-05, 2005, Specification for Bridge Design, The Ministry ofTransportation, Hanoi.
Architectural Institute of Japan, 2001, Recommendations for Design of Building
Foundations, 2nd edition, Japan.
Davisson, M. T., Manuel, F. S., and Armstrong, R. M., 1983. Allowable Stresses
in Piles, FHWA-RD-83-059, Federal Highway Administration.
Japan Road Association, 2012, Specifications for Highway Bridges, Japan.
JFE-IPTE/NUCE, 2012, Research for Introduction of JFE R&D Steel Productsfor High-rise Buildings and Bridges in Vietnam, Research report, Hanoi.
Ngu, V. C., and Thai, N., 2006, Pile foundation: Analysis and design, Hanoi. (inVietnamese)
TCXD 205-1998, 1998, Pile foundation - Specifications for design, The Ministryof Construction, Hanoi.

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Contemporary timber building in Japan, 2013
Mikio KOSHIHARA
Professor, Institute of Industrial Science,
the University of Tokyo, Japan
kos@iis.u-tokyo.ac.jp

ABSTRACT
Revision of the Building Standards Law 2000 allowed the construction of timber buildings fourstory or taller with fire-resistance performance. The possibilities of mid-rise and large timberbuildings in Japan are extended.
For fire-resistance three type of members were developed and achieved in Japan. First type is amembrane member covered with fireproof elements like gypsum boards. Second type is a built-in
steel member for self-extinguish. Last third type is a fire-stop, ‘Moedomri’, member covered withwood and non-combustible treat wood. First layer wood functions as a ‘Moeshiro’ layer for making
fire-prevention time and second layer wood functions as a ‘Moedomari’ layer for self-extinguish.
With membrane member many large timber building have been built from 2005. Typical structural
system is 2x4 system and post and beam system. Shimouma building reported in 2012 used this fireprevention system. M-Bldg. reported in 2012 use a built-in steel system. Finally timber buildings
with ‘Moedomari’ are completed in 2013.
This paper describes the detail of large timber buildings with three fire prevention system in Japan,
2013.
Keywords: Mid-rise timber building, Large timber building, Fire prevention,

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A useful approach to identify and analyze
factors affecting safety on construction
site with lifting equipmentin Vietnamese environment
Thanh Long NGO1, Van Gon BUI2, Dinh Sung PHAM3
Quoc Dung NGUYEN4 and Chi-Chen TSAI5
1
Assistant Professor, Department of Construction Mechanical Engineering,
National University of Civil Engineering, Vietnam
ntlongntu@yahoo.com
2
Lecturer, Department of Construction Mechanical Engineering, National
University of Civil Engineering, Vietnam
3
Lecturer, Department of Construction Mechanical Engineering,
National University of Civil Engineering, Vietnam
4Lecturer, Department of Construction Mechanical Engineering,
National University of Civil Engineering, Vietnam
5Ph.D. Candidate, Department of Civil Engineering, National
Taiwan University, Taiwan
ABSTRACT
Lifting equipment is the centerpiece of production on today’s typical building
construction sites. Lifting equipment hoists and transports a variety of loads nearand above people and other construction types of equipment, working under thecrowded environment, overlapping zones, time, budget, and labor constraints. The
safety risk relating to lifting equipment further increases on construction sites in
the world, especially in Vietnam, and it has not been paid any adequate attention
by researchers and users as well. This paper presents a useful approach toidentify and analyze factors affecting safety in lifting equipment environments inconstruction sites in Vietnam. The research methodology is based on previous
studies’ results and real construction environment in Vietnam. The proposed
approach includes comprehensive questionnaire of experts who have lifting
equipment working experience, such as lifting equipment operators, safety
managers, equipment managers, and designers in order to identify these factors,
and it has been used statistical techniques to analyze and evaluate them. The stepsof the proposed approach are showed in this paper. The result of the paper is very
useful for future studies in the construction machines safety management field in
Vietnam.
Keywords: lifting equipment, construction sites, fatalities, safety, Vietnam
1. INTRODUCTION
Vietnam’s construction industry has been increasing to meet the needs of its rapid
economic growth. The construction sector contributes 42% to Vietnam’s gross209

October
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Hanoi,Hanoi,
Vietnam0ctober
Vietnamdomestic product (GDP) in 2007 (Bloomberg, 2008). However, safety
performance in construction industry has raised concerns in recent years(Mohamed et al., 2009), and construction industry has very high injury andfatality rates compared to other industries (Rivara and Alexander, 1994; Tam andFung, 2011).
Types of lifting equipment including mobile cranes, tower cranes, and lifts
are the really important machines in construction sites in the world and in
Vietnam as well. Lifting equipment certainly contributes to the high number of
construction injuries and fatalities (Shapiro and Shapiro, 2004; Skinner et al.,2006; Neitzel et al., 2001; Van Hamptom and Lawis, 2008; Shapira et al., 2012).
For example, according to the statistics from Occupational Safety and Health in
the United States (Kang and Miranda, 2007), there were 137 crane-related
fatalities recorded from 1992 to 2001 in the United States. Japan recorded 41
fatalities resulting from crane accidents in 2006 (Kawata, 2007). Tam and Fung(2011) showed that there were 12 accidents of tower cranes from 1998 to 2005 in
Hong Kong. A British study found that cranes are involved in 17% of all
construction fatalities in British (Health and Safety Executive, 1978). Vietnam
reported that there were 74 accidents of lifting equipment from 2000 to 2004
(Ministry of Labour-Invalids and Social Affairs, 2013). However, there had no
specific information about the activities or actions leading to these injuries, andthey did not identify causal factors or environments (Neitzel et al., 2001).
Identification and analysis of factors affecting safety on construction sites
with types of lifting equipment have become urgent issues. As a result, there aresome studies in this field, but they have done in American and European
construction sites (Shapira and Lyachin, 2009). In addition, these studies have
only focused on one or some types of lifting equipment, and it can come acrosssome difficulties during using result of these studies in Vietnamese construction
environment. This paper addresses an approach that can be effectively applied to
identify and analyze factors affecting safety on construction sites with lifting
equipment in Vietnam. The proposed approach includes comprehensive
questionnaire of experts, and statistical techniques have been used to analyze andevaluate them.
2. LITERATURE
Construction sites are increasing use of lifting equipment as the dominantmachines in recent years, but they have a fairly numerous number of accidents
involving types of lifting equipment have occurred (Shapira et al., 2012).
Therefore, lifting equipment safety management field at construction sites has
attracted some leading studies.
Some studies have used statistics as knowledge source to show major
causes of fatalities in the use of crane. Neitzel et al. (2001) reviewed crane related
injury data to find and evaluate major causes of fatalities in the use of crane.
Beavers et al. (2006) used the Occupational Safety and Health Administration’s(OSHA) case files from crane-related fatality investigations during the years
1997–2003, the paper examined the data to determine the proximal causes andcontributing physical factors. In reality, however, statistics suitable to serve the210

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purposes of current study hardly exist-for tower or mobile cranes (Shapira andLyachin, 2009).
There have been some studies that proposed some quantitative approaches
to identify and measure factors affecting crane safety on construction sites.
Shapiro and Shapiro (2004) showed that in crane and rigging, most failures ariseout of one or ten categories, such as deficient equipment; pressure from cost or
time constraints; inexperienced management; lack of training, knowledge, or skill;inadequate planning; unreasonable demands of owner or management;
environmental conditions; unclear instructions; operator errors; changed
circumstances. Shapira and Lyachin (2009) showed twenty one major factors
affecting safety in tower-crane environments and evaluated the degree to which
each factor influences ongoing safety on site. Twenty one factors are divided into
four factors groups including project conditions factor (ten factors), environment
factor (three factors), human factor (five factors), and safety management factor(three factors). The research was based on comprehensive questioning of anexpert team that included the safety managers and equipment managers of leading
construction companies with Delphi technique. Shapira and Simcha (2009a) used
nineteen senior construction equipment and safety experts interviewed and led
through the analytic hierarchy process (AHP). The research found out the final
weights of thirteen major factors affecting safety on construction sites, and thesefactors include site-level safety management, operator proficiency, wind,superintendent character, maintenance management, company-level safety
management, overlapping cranes, operator character, signalperson experience,
blind lifts, type of load, employment source, and length of work shift. These
weights can be used to produce a tower crane safety index for any individual site.
Shapira and Simcha (2009b) proposed a method, which addresses quantitative
measurement and risk scales of safety hazards on construction sites due to thework of tower cranes. The research focused on two factors overlapping cranes andoperator proficiency. A probability-based method was prescribed for themeasurement of overlapping cranes, while the analytical hierarchy process
method and knowledge elicitation from experts were applied to develop metrics
for operator proficiency. Shapira et al. 2012 presented an integrative model for
quantitative evaluation of safety on construction sites with tower cranes. The
model integrated for modules: (1) nonsite-specific relative weights of safety
factors, (2) measurement of the magnitude of each safety factor actually present
on site, (3) scales to convert each measured magnitude into a value representing
the potential risk generated by each factor present on site, and (4) multiplying
factors to convert the cumulative risk generated by all factors into actual risk.
However, these studies only focus on crane safety management and measurement,
and they were done in construction environments with enough information andhigh levels of reliability while construction environments in Vietnam are different
from them. As a result, these models may need to modify during applying them inconstruction environments in Vietnam.
3. METHODOLOGY
Following approaches from the previous studies and basing on construction
environment in Vietnam, the paper analyzes and evaluates them and then proposes
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October
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Vietnama useful approach to identify and analyze factors affecting safety on construction
site with lifting equipment in Vietnam. The whole research methodology ispresented as in the Figure 1.
Current approaches

Construction
environment in Vietnam

Analyze and evaluate

Propose a useful approachfor construction
environment in Vietnam
Figure 1: Research methodology
4. A USEFUL APPROACH FOR CONSTRUCTION ENVIROMENT IN
VIETNAMAn approach can be effectively used to identify and analyze factors that affectsafety on construction sites with lifting equipment in Vietnamese environment
including 6 steps described as in Figure 2.
4.1 Step 1: An initial list of factors from literature and the condition of
construction site in Vietnam
The valuable studies include Shapiro (2004), Shapira and Lyachin (2009), Shapira
and Simcha (2009a, 2009b). These studies offered important factors that affectsafety of lifting equipment on construction sites, and in which many factors can beused in Vietnamese Environment. However, in Vietnam, there are someconditions differing from these studies’ conditions, such as project conditions,environment, human factor, design and manufacture, and safety management.
Thus, initial list of factors need to base on both of literature and Vietnamese
environment.
4.2 Step 2: Exploratory interviews
An open-ended questionnaire survey first is conducted with some professionals
through face-to-face, e-mail, or phone calls. All these experts are either the safetyor equipment managers of leading construction companies in Vietnam. Theseexperts include equipment managers, safety managers, hold both positions,designers and manufacturers, and they have at least five years of working
experience in this field (Ling and Poh, 2008; Bo and Chan, 2012). This step is

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often used to determine the major facets of a set of data, by simply counting thenumber of times an activity happens, or a topic is depicted (Fellow and Liu, 2008).
Step 1An initial list of factors from literature and theconditions of construction site in Vietnam
Step 2
Exploratory interviews
Step 3
Surveys (Identify factors according to a
five-point Likert scales)
Step 4: Methods of data analysis
Mean score ranking technique
Cronbach’s Alpha reliability test
Kendall’s concordance analysis
t-TestStep 5
Analysis and discussion of survey results
Step 6
Conclusions and recommendations
Figure 2: The approach to identify and analyze factors affecting safety on
construction site with lifting equipment in Vietnamese environment
4.3 Step 3: Surveys
A three-part questionnaire is designed. The first section comprises general
instructions that guide the respondents how to tick in the questionnaire. The
second section is to take general information of the respondents. The third section
includes a list of factors that affect safety on construction site with lifting
equipment. The respondents are asked to rate the extent to which they agree witheach statement, where 1 = strongly agree, 2 = agree, 3 = neither agree nor disagree,
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4 = disagree, and 5 = strongly disagree. The respondents are invited to state otherfactors and rate them. Questionnaires can be sent by post and e-mails to about 50
respondents who have working experience in this field.
4.4 Step 4: Methods of data analysis
4.4.1 Mean score ranking technique
Descriptive statistics and the mean score ranking technique is adopted to therelative importance of various factors that affect safety on construction site withlifting equipment using the Statistical Package for Social Sciences (SPSS). The
five-point Likert scale described above is used to calculate the mean score foreach factor, which is then used to determine their relative ranking in descendingorder of importance.
4.4.2 Cronbach’s alpha reliability test
The Cronbach’s alpha reliability (the scale of coefficient) measures are used toverify the internal consistency amongst the respondents under the adopted Likert
scale of measurement regarding factors affecting safety on construction site withlifting equipment in Vietnamese environment. The Cronbach’s alpha coefficients
range from 0 to 1 in value and may be used to show the reliability of factors
extracted from multi-point formatted questionnaires or scales (Sanotos, 1999). If
the items making up the score are all identical and perfectly correlated, then  = 1.
If the items are all independent, then  = 0. Thus, the higher the score, the morereliable the generated scale will be. Tuckman (1999) and Yip and Poon (2009)
recommended acceptable alpha values of 0.5 for attitude/perception assessment.
The Cronbach’s alpha tests are applied to test the reliability of the scales of factors
in the questionnaire survey.
4.4.3 Kendall’s condordance analysis
The Kendall’s coefficient of concordance (W) is used to measure the agreement ofdifferent respondents on their rankings of factors based on mean values within aparticular survey group. This analysis aims to find out whether the respondents
within an individual group respond in a consistent manner or not (Chan et al.,2011). Values of W can range from 0 to 1, with 1 exhibiting perfect agreement
and 0 indicating perfect disagreement. In the other hand, a high or significant
value of W reflects that different parties are essentially applying the same
standard in ranking factors (Daniel, 1978; Chan et al., 2011). However, according
to Siegel and Castellan (1988), W is only suitable when the number of attributes isless than or equal to 7. If the number of attributes is greater than 7, chi-square isused as a near approximation instead. If the actual calculated chi-square value
equals or exceeds the critical chi-square value got from the table for a certain levelof significance and a particular value of degrees of freedom, then the null
hypothesis that the respondents’ sets of ranking are unrelated to each other withina survey group can be rejected.

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4.4.4 t-Test
t-Test of the mean is carried out with the help of SPSS to ascertain whether the
respondents will agree that the factors affecting safety on construction sites withlifting equipment. For each attribute, the null and alternative hypotheses are set
out below.  is the population mean, and 0 is fixed at 3, ratings below 3
represented respondents’ agree with the problem. Null hypothesis H0:   0. The
decision rule was to accept H0 when p  0.05. Therefore, when the calculated t
value has significance of  0.05, it is concluded that the issue is not a significant
problem to the owner. Alternative hypothesis H1:  < 0. The decision rule was toaccept H1 (and reject H0) when p < 0.05 and the t value is negative. Thus, when
the calculated t value has significance of < 0.05, it is concluded that the factor hasa significant influence of safety on construction site (Ling and Poh, 2008).
4.4.5 Step 5 and 6: Analysis and discussion of survey results; conclusions andrecommendations
The results derived from the analysis of empirical questionnaire survey will becross-referenced to the literature and to complement each other for validation.
Finally, valuable conclusions and helpful recommendations for parties involved(e.g., construction firms, regulatory and enforcement authorities, etc.) should beshowed.
5. CONCLUSIONS AND FUTURE RESEARCHThis paper presented steps of the useful approach to identify and analyze factorsthat affect safety in lifting equipment environment in Vietnam. The approach isbased on the experience and expertise of safety managers, equipment mangers,and designers and manufacturers. These experts will assess the influence of eachof the factors, thus making it possible to distinguish between factors that exert astrong influence and those that exert a moderate influence on site safety. In
addition, the proposed approach uses fairly reliable methods of data analysis.
However, the proposed approach needs to be verified by some real studies, so it isvery important for the research directions in the future.

REFERENCES
Beavers, J. E., Moore, J. R., Rinehart, R., and Schriver, W. R., 2006. Cranerelated fatalities in the construction industry. Journal of Construction Engineeringand Management 132, 901-910.
Bloomberg, 2007. Vietnam’s economy grew by a decade high in 2007. Bloomberg,
Jan. 1, 11.
Bo, X., and Chan, A. P. C., 2012. Investigation of barriers to entry into the designbuild market in the people’s republic of China. Journal of Construction
Engineering and Management 138, 120-127.
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identify andanalyzefactors
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Chan, D. W. M., Chan, A. P. C., Lam, P. T. I., and Wong, J. M. W., 2011. An
empirical survey of the motives and benefits of adopting guaranteed maximum
price and target cost contracts in construction, International Journal of ProjectManagement 29, 577-590.
Daniel,W.W., 1978. Applied nonparametric statistics. Houghton Mifflin, Boston.
Fellow, R., and Liu, A., 2008. Research methods for construction, Wiley
Blackwell, UK.
Health and Safety Executive, 1978. One hundred fatal accidents in construction.
Her Majesty’s Stationary Office: London, England.
Kang, S., and Miranda, E., 2007. Physics based model for simulating the
dynamics of tower cranes. Stanford University, United Kingdom.
Kawata, M., 2007. Safety use of cranes in the construction industry. Occupational
Safety and Health Council, Hong Kong Special Administrative Region.
Ling, F. Y. Y., and Poh, B. H. M., 2008. Problems encountered by owners ofdesign–build projects in Singapore. International Journal of Project Management26, 164-173.
Ministry of Labour-Invalids and Social Affairs, 2013. Labour accidents withcauses <http://www.molisa.gov.vn/Default.aspx?tabid=193&temidclicked=342>
Mohamed, S., Ali, T. H., and Tam, W. Y. V., 2009. National culture and safe
work behaviour of construction workers in Pakistan. Safety Science 47, 29–35.
Neitzel, R. L., Seixas, N. S., and Ren, K. K., 2001. A review of crane safety in theconstruction industry. Applied Occupational Environmental Hygiene 16, 1106–
1117.
Rivara, F. P., and Alexander, B. H., 1994. Occupational injuries in clinical.
Occupational, and Environmental Medicine, Saunders, Philadelphia.
Sanotos, J. R. A., 1999. Cronbach's alpha: a tool for assessing the reliability of
scales. Journal of Extension 37, 1-5.
Siegel, S., and Castellan Jr, N. J., 1988. Nonparametric statistics for behaviouralsciences, 2nd ed., McGraw-Hill, New York.
Shapira, A., and Lyachin, B., 2009. Identification and analysis of factors affecting
safety on construction sites with tower cranes. Journal of Construction
Engineering and Management 135, 24-33.
Shapira, A., and Simcha, M., 2009a. AHP-based weighting of factors affecting
safety on construction sites with tower cranes. Journal of Construction
Engineering and Management 135, 307-318.
Shapira, A., and Simcha, M., 2009b. Measurement and risk scales of crane-related
safety factors on construction sites. Journal of Construction Engineering andManagement 135, 979-989.
Shapira, A., Simcha, M., and Goldenberg, M., 2012. Integrative model for
quantitative evaluation of safety on construction sites with tower cranes. Journalof Construction Engineering and Management 138, 1281-1293.
Shapiro, L. K., and Shapiro J. P., 2004. Cranes and derricks, 4th Ed., McGrawHill, New York.
Skinner, H., Watson, T., Dunkley, B., and Blackmore, P., 2006. Tower cranestability. CIRIA C654, CIRIA, London.
Tam, V. W. Y., and Fung, I. W. H., 2011. Tower crane safety in the constructionindustry: A Hong Kong study. Safety Science 49, 208-215.
Tuckman, B.W., 1999. Conducting educational research, 5th ed., Wadsworth
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Yip, R. C. P., and Poon, C. S., 2009. Cultural shift towards sustainability in theconstruction industry of Hong Kong. Journal of Environmental Management 90,
3616-3628.

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Recycled glass concrete beams
under bending and shear
Kiang Hwee TAN
Professor, Department of Civil & Environmental Engineering
National University of Singapore, Singapore
tankh@nus.edu.sg

ABSTRACTAs an effort towards the sustainability of concrete as a construction material,
waste glass was considered as a substitute for fine aggregates in this study. The
flexural and shear behavior of reinforced concrete (RC) beams with recycled
glass as 50% and 100% of fine aggregates were investigated. The recycled glassconsisted of green and brown glass particles in equal proportions. The beams
were examined in terms of cracking and deformation characteristics, as well as
ultimate strength and mode of failure. Test results indicated that recycled glass
concrete beams similar flexural and shear characteristics as normal concretebeams. The findings therefore demonstrated the technical viability of using waste
glass particles as fine aggregates in concrete.
Keywords: flexure, recycled glass, reinforced concrete, shear, sustainability.

1. INTRODUCTION
Concrete is the second most used commodity after water, and has been used since
the 5th century BC. It is typically mixed with 6% air, 10% cement, 18% water,
25% sand (that is, fine aggregates) and 41% gravel (that is, coarse aggregates).
The manufacture of cement, which results in 0.8 to 1.0 ton of CO2 being released
into the atmosphere for every ton of cement production, has raised concerns on its
impact on the global carbon footprint. At the same time, the harvesting of sandand gravel which results in deforestation and ecological damage has become anenvironmental issue in many countries. As such, initiatives have been set up toaddress the issue of sustainability of concrete as a construction material.
On the other hand, the effluence of society has resulted in more and more urban
waste such as paper, plastic and glass, being generated. These wastes have amuch lower recycling rate compared to construction waste. The disposal of such
waste poses an environmental problem, as landfills are limited. It is therefore
natural to consider the use of such waste in the production of concrete. This study
was carried out to investigate the feasibility of using waste glass as sandreplacement in structural concrete members.
The flexural and shear behavior of reinforced concrete (RC) beams with mixedcolor glass as 50% and 100% of fine aggregates were investigated. The mixed-219

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color glass consisted of green and brown glass particles in equal proportions. The
beams were examined in terms of cracking and deformation characteristics, aswell as ultimate strength and mode of failure. The results were compared tonormal RC beams with natural sand as fine aggregates

2. TEST PROGRAM
In this study, soda-lime glass in the form of waste glass bottles were collectedfrom a local recycler. Those bottles were originally used to contain beer or wine.
Glass for this purpose is primarily produced in green or brown colors. Green
glass is colored by oxides of Cr and Co, while brown glass is produced by adding
oxides of Mn, Fe, Ni, and Co (Christensen and Damaggard, 2010). The glass
bottles were delivered from the recycling plant in the condition just prior todisposal into landfills.
Before crushing, the glass bottles were cleaned and sorted in the following
manner. First, the bottles were immersed in tap water for one day. Next, themetal/plastic caps and neck-caps, wooden corks, as well as plastic/paper labels
were removed. Then, the surface of glass bottles was cleaned with tap water, andfinally, the glass bottles were separated by color. The green and brown glass
bottles were found to have negligible contamination after washing.
The crushing process was done using a jaw crusher, with the output size of theglass particles manually adjusted. Glass bottles were efficiently reduced in size
into the range specified by ASTM C 33 (2003) for sand, as shown in Figure 1.
The crushed glass particles exhibited angular shape, sharper edge, smooth surface
texture and higher aspect ratio than natural sand, because of its brittle
characteristics (see Figure 2).

Percentage passing, %100

ASTM C33 limit

80
60

Glass sand40
20

Natural sandCoarse aggregate

0
0.1

1

10

Sieve size, mm

Figure 1: Gradation of glass particles and natural aggregates

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Figure.2: Appearance of typical glass and natural sand
The saturated surface dry (SSD) specific gravity and water absorption capacity ofglass particles were determined according to ASTM C 128 (2007) to be 2.53 and
0.07% respectively. Chemical compositions of glasses with different colors wereanalyzed by energy dispersive spectrum X-ray spectroscopy (EDS) and the results
are shown in Table 1 together with those of natural sand and cement..
Table 1: Chemical compositions of glass particles, natural sand and cement
Composition, %
SiO2
Al2O3
Fe2O3
CaO
MgO
Na2O
K2O
TiO2
Cr2O3
SO3

Glass particles
Green Brown
71.22
72.08
1.63
2.19
0.32
0.22
10.79
10.45
1.57
0.72
13.12
13.71
0.64
0.16
0.07
0.1
0.22
0.01
—
—

Natural sand

Cement

88.54
1.21
0.76
5.33
0.42
0.33
0.31
0.05
—
—

20.8
4.6
2.8
65.4
1.3
0.31
0.44
—
—
2.2

2.1 Test Specimens
Eighteen beams were fabricated and tested. The beams were divided into two
main groups, with nine beams for flexural tests (Group BF) and another nine forshear tests (Group BS), as shown in Table 2. The main test parameter was thetensile steel ratio for former group, and shear span to effective depth ratio for thelatter group. For each test parameter, the glass-to-fine-aggregate content wasvaried as 0%, 50% and 100%. Group GF beams were designated BFm-n, wherem denotes the diameter of tensile reinforcing bars, and n denotes the glass-to-fineaggregate ratio, in percentage (%). Group BS beams were designated BSx-y,

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where x denotes the shear span-to-effective depth ratio, and y the glass-to-fineaggregate ratio (%).
Table 2: Test parameters and results
GlassUltiConcrete
to-finecompress- mate
FailBeamaggregload,ure
Gp. designative
ate
Pu
mode
ion
strength,ratio,(kN)
fcm (MPa)
g/fa
BF10-0
0
44.4
39.1
FT
1.24
BF10-50
50
42.0
36.7
FT
BF10-100
100
39.0
37.2
FT
BF13-0
0
48.0
57.2
FT
BF
4.7~4.8
2.12
BF13-50
50
42.0
51.9
FT
100
39.0
53.4
FT
BF13-100
BF16-0
0
40.0
81.1
FC
3.24
BF16-50
50
39.5
77.8
FC
BF16-100
100
37.6
65.4
FC
BS1.8-0
0
42.0
121.0
FT
1.8
BS1.8-50
50
42.3
122.0
SC
100
39.7
134.3
BS1.8-100
FT
BS2.4-0
0
39.7
36.0
SB
2.4
BS BS2.4-50
1.24
50
42.3
54.7
SB
BS2.4-100
100
39.7
52.6
SB
BS3.5-0
0
39.0
41.6
SB
3.5
BS3.5-50
50
42.3
39.6
SB
BS3.5-100
100
39.7
49.8
SB
Note: FT – flexural tension; FC – flexural compression; SC – shear-compression;
SB – shear-bond.
Tensilesteel
ratio,ρ (%)

Shearspan –
effective
depth
ratio,
a/d

The concrete mix consisted of cement, fine aggregates, coarse aggregates, andwater in the proportion of 1 : 1.90 : 1.61 : 0.49 by weight. The cement content
was 460 kg/m3. The target slump was 100 mm and characteristic cylinder
strength was 30 MPa.
The reinforcement cages for the beams are shown in Figure 3. For Group BF
beams, each beam measured 2 meters in length. The longitudinal reinforcement
consisted of two deformed bars with diameters of 10 mm, 13 mm or 16 mm (seeTable 2), and except for the middle third-length, the beams were provided withclosed links with a diameter of 6 mm at a spacing of 90 mm. For Group BS
beams, the length varied according to the desired shear span-to-effective depth
ratio. The longitudinal reinforcement consisted of two deformed bars with adiameter of 10 mm, and no transverse reinforcement was provided.

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AA
225 / 300 / 450

225 / 300 / 450

124
/ 125
/ 127

/ 2xφ13/ 2xφ10

Cross-section A-A

Figure 3: Reinforcement details of test beams (All dimensions are in mm)

2.2 Material Properties
Ordinary Portland Cement (OPC) was used. The fine aggregates consisted ofboth natural sand and waste glass particles. The glass particles were obtained bycrushing waste soda lime glass bottles and sieving to remove particles which arelarger than 4.75mm. Granite of a maximum size of 10 mm was used as coarse
aggregates.
The average yield strength of 6, 10, 13 and 16 mm bars were 452, 573, 480 and
503 MPa, respectively, each determined based on three samples.
The
corresponding elastic moduli were 199, 205, 193 and 199 GPa, respectively.
2.3 Beam Fabrication and Test Instrumentation
The reinforcement cage was assembled and strain gauges were fixed on thelongitudinal steel bars at mid-length and on the closed links as shown in Figure 4.
The beams were cast in wooden formwork, which was removed one day later.
They were then placed under wet gunny sacks for a week.
Accompanying cubes and cylinders for the determination of concrete compressive
strength were prepared at the same time and cured in the same manner. After that,the beams were placed in the laboratory under ambient condition until the day of
testing, which was typically 28 days after casting.

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P/2

P/2

Curvature measuring device
Strain gauges

Displacement transducer

Figure 4: Test set up and instrumentation
The test set-up is also shown in Figure 4, with the beam subjected to four-point
bending. Strain gauges were placed on the top of the beam at mid-span and on theside face of the beam in both the transverse and longitudinal directions in the caseof Group BS beams, at approximately one effective-depth distance from theloading points. A device using two transducers placed one each above and below
the beam was used to measure the beam curvature at mid-span. In addition, themid-span deflection of the beam was monitored using a linear variabledisplacement transducer (LDVT). The cracking characteristics were noted as thebeam was loaded to failure.

3. TEST RESULTS AND DISCUSSION
In general, the behavior of the beams was found to be similar regardless of theglass-to-fine-aggregate ratio, g/fa. The appearance of the beams after testing isshown in Figure 5. As indicated in Table 2, the beams exhibited approximately
the same ultimate load-carrying capacity, Pu, and the same failure mode,
especially for Group BF beams that failed in flexure. For Group BS beams, somedifference in shear capacity was observed with different g/fa ratios, but this wasprobably due to the scatter nature related to shear resistance of structural concrete,especially for small span-to-effective depth ratio, a/d. The failure was by shearbond except for BS1.8-y beams. Due to a small a/d ratio of 1.8, BS1.8-y beams
failed by shear-compression or flexural tension, as the corresponding beam
capacities were close to one another.
3.1 Flexural characteristics
The load versus mid-span deflection curves for BF-10-n, BF-13-n and BF-16-n
beams are shown in Figure 6. BF-10 beams with a tensile steel ratio of 1.24%,
were designed as under-reinforced beams. In these beams, cracks were firstobserved at about 6 kN. This was followed by a reduction in beam stiffness as
cracks developed further. The longitudinal steel was observed to yield at about 35
kN. The beams exhibited ductile behavior before they finally failed in flexural
tension, with the extreme concrete compressive fiber reaching a strain of 0.0035
to 0.0045. There was no difference in the flexural characteristics due to thedifferent g/fa ratios.

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ICUS Report 73(a) BF-10 beams (ρ = 1.24%)(d) BS-1.8 beams (a/d = 1.8)(b) BF-13 beams (ρ = 2.12%)(e) BS-2.4 beams (a/d = 2.4)(c) BF-16 beams (ρ = 3.24%)(f) BS-3.5 beams (a/d = 3.5)

Figure 5: Appearance of beams after tests (bottom to top: g/fa = 0, 50, 100%)

Load, P (kN)g/fa = 0
50% 100%

g/fa = 050%

g/fa = 0
50%
100%

100%
BF10

BF13

BF16

Mid-Span Deflection, ∆ (mm)Figure 6: Load versus deflection characteristics of Group BF beams
BF-13 beams had a tensile steel ratio of 2.12%, approximately equal to thebalanced steel ratio. The beams exhibited similar behavior as BF-10 beams
except for a smaller reduction in beam stiffness after cracking, a higher yield load
and a limited ductility at failure. Again, there was no significant difference
among the beams. BF-16 beams were designed with a tensile steel ratio of 3.24%,
that is, as over-reinforced beams. After cracking at about 8.5 kN, there was a

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small reduction in beam stiffness, and the beam failed by concrete crushing justprior to the yielding of the longitudinal steel reinforcement. The difference inbehavior among the beams was small. The maximum concrete strain measured at
the extreme compressive fiber was between 0.003 and 0.004 for these two subgroups of beams.

Load, P (kN)

Figure 7 shows the observed maximum width of flexural cracks in the beams. The
maximum crack width was measured at the level of the tensile longitudinal
reinforcement. It is noted the crack widths tend to be smaller with a higher
percentage of glass particles; however, the difference is not significant.

100%

100%

100%

g/fa = 50%

g/fa = 50%

BF10

BF13

g/fa = 50%
BF16

Maximum crack width, wcr (mm)Figure 7: Maximum crack widths in Group BF beams
3.2 Shear characteristics
The load versus mid-span deflection curves for Group BS beams are shown in
Figure 8. Except for BS1.8-0 and BS1.8-100, which failed by flexural tension, allbeams failed abruptly by shear bond or shear compression.
No significant
difference due to different glass-to-fine aggregate ratios was observed.

50%
Load, P (kN)g/fa = 0%
g/fa=0%
100%
50%
BS1.8

100%

100%
g/fa = 0%

50%

BS2.4

BS3.5

Mid-Span Deflection, ∆ (mm)Figure 8: Load versus deflection characteristics of Group BS beams

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4. CONCLUDING REMARKS
Previous studies (Du, 2011) have shown that recycled glass concrete with glass
particles as fine aggregates do not differ much from normal concrete in properties
at the freshly mixed state. Only a slight reduction in fresh density, marginalincrease in air content and negligible change in slump, were observed.
Also, the mechanical properties of concrete were not affected by the use ofrecycled glass particles. On the contrary, there could be an increase in thecompressive strength, flexural and splitting tensile strengths, and static modulus.
Drying shrinkage was also found to reduce in recycled glass concrete with lower
water-cement ratio. Resistance to chloride ion penetration was found to besignificantly higher in recycled glass concrete. Furthermore, recycled glass
concrete was found to show innocuous alkali-silica expansion in accelerated
mortar bar tests using mortar screened from recycled glass concrete.
The tests carried out and reported herein demonstrated that both the flexural andshear behavior of reinforced concrete beams with glass particles as fineaggregates are essentially the same as those of normal reinforced concrete beams.
Hence, it is feasible to use waste glass particles in concrete without compromisingon the mechanical and structural properties of concrete and concrete members.
Further field studies would be appropriate before it can be implemented inpractice.

REFERENCES
ASTM C 33-03, 2003. Standard Specification for Concrete Aggregates. WestConshohocken, PA: ASTM International.
ASTM C 128-01, 2007. Standard Test Method for Density, Relative Density(Specific Gravity), and Absorption of Fine Aggregate. West Conshohocken, PA:
ASTM International.
Christensen, T. H., and Damaggard, A., 2010. Recycling of Glass. In Christensen,
T. H. (editor), Solid Waste Technology & Management, John Wiley & Sons,
Chichester.
Du, H., 2011. Glass Sand Concrete and “Sandless” Concrete. PhD Thesis,
National University of Singapore, Singapore.

Recycled glass
concretebeams
underbeams
bendingandbending
shear and shear
Recycled
glass
concrete
under

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Strength of beam-column joint
in soft-first story RC buildings
Toshikatsu ICHINOSE1, Sefatullah HALIM2, Susumu TAKAHASHI3,
Masaomi TESHIGAWARA4, Takashi KAMIYA5 and Hiroshi FUKUYAMA6
1
Professor, Nagoya Institute of Technology, Japan.
ich@nitech.ac.jp
2
Ph.D Student, Nagoya Institute of Technology, Japan
3
Assistant Professor, Nagoya Institute of Technology, Japan.
4
Professor, Nagoya University, Japan.
5
Chief Research Engineer, Yahagi Construction Co., Ltd, Japan.
6
Director, Building Research Institute, Japan.

ABSTRACTThis paper describes the strength of reinforced concrete (RC) beam-column joints
in buildings with soft-first story. In such a building, the sections of first story
columns are usually much larger than those of second story columns. To
investigate the strength of the joint, specimens are constructed and tested. Test
parameters are hoops in the beam-column joint, beam reinforcements, stirrups in
the beam and axial force. The test result shows that the beam reinforcements andstirrups are effective to prevent joint failure. The force-resistant mechanisms ofthese joints are different from those of usual beam-column joints, because sign ofbending moment in the second story column is same as that of the first story
columns in these joints. Failure modes of these joints are also different from thoseof usual beam-column joints. Strut-and-tie models are developed for the
specimens. The developed models agreed with the test results.

Keywords: strength, reinforced concrete, beam-column joint, strut-and-tie model,
soft-first story, seismic design

1. INTRODUCTION
Reinforced concrete (RC) buildings with soft first story are popular because thelarge space in the first story serves as a parking lot, commercial space, or othersimilar purposes. However, as shown in Fig. 1, many collapses occurred in soft
first story in the 1995 Kobe earthquake. In Japan, researchers proposed tostrengthen the columns in the soft first story after the 1995 Kobe earthquake. As aresult of such experiences and researches, many RC buildings are being
constructed in Japan with a soft first story in which the sectional area of the firststory column is larger than those of the upper stories to prevent story collapse as
shown in Fig. 2. In this paper, the joints shown in Figs. 2a and 2b are called “Itype” and “O-type” joints, respectively, where the first-story columns areextended toward the inside and outside of the frame.

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In either case, the vertical reinforcements in the extended area of the first-story
column are anchored to the beam-column joint. A question arises whether thejoint may fail before the column exhibit its strength. In fact, the joint in Fig. 1 ismore damaged than the column.
In this study, a test is conducted to investigate the strength and failure modes ofboth loading directions and both type of joints. In addition, the reinforcements
effective in strengthening the beam-column joint in soft first story are discussed.

Figure 1 Joint failure in soft story

Closing

Closing
2800 mm

Opening

Opening(a) I-type joint(b) O-type joint
Figure 2 Two types of buildings with soft-first story

2. EXPERIMENTAL PROGRAM
Two specimens of each type of building are constructed: Specimens I-1 and I-1t
for the building shown in Fig. 2a and Specimens O-1 and O-1t for the building
shown in Fig. 2b. The area around the joint denoted by the dashed line in Fig. 2 isused as specimen to investigate the strength of the beam-column joint. The
specimens are 1/2 scale models constructed upside down to easily apply the forces.
Figure 3 shows the test setup and the dimensions of Specimen I-1, where thespecimen and test setup are drawn upside down to treat the specimen as a part ofan actual building. The stub column at the left end of the specimen is constructedto prevent the flexural failure of the wall panel that never occurs in real buildings.
The loading point is assumed to be the middle point of the clear height of the first230

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story; therefore, 700 mm in Fig. 3 corresponds to one-fourth of the story height(2800 mm in Fig. 2). The displacement is controlled at the lateral loading point.
The lateral drift is defined as the ratio of the lateral displacement at the loading
point to 700 mm. The applied axial load is shown in Table 1 where the positive
value represents compressive axial force. The axial load is constant up to the driftof 0.5%. Considering the overturning mechanism of the building due to larger
displacements, the axial load is changed for opening and closing directions.
Figure 4 shows the detail of Specimen O-1t. The detail of Specimen I-1t isreported by Ogawa et al (2012). The shape of Specimens I-1 and O-1 are identicalto those of I-1t and O-1t, respectively. However, the numbers of stirrups, hoops in
the joint, and beam reinforcements of I-1t and O-1t are larger than those of I-1 andO-1, respectively (red-, blue-, and green-colored reinforcements in Fig. 4 areprovided only in I-1t and O-1t). The yield strengths of the steel bars are between
369 and 389 MPa. The pro compressive strengths of concrete are between 25.5
and 26.4 MPa.

500

1250

250

Lower stubReaction floor

Pin

Pin

Negative

Positive← →←Axial load

1750 mm

700 mmStub column

Reaction wall

Horizontal load

Pin

RollerCounter weight

Figure 3 Test set up and dimensions of specimen I-1 [mm]Table 1 Applied axial load
SpecimenI-1

R ≤ 0.5 %

Open

O-1

Close

I-1t

Open

1125 kN(η = 0.15)

500 kN(η = 0.07)

R > 0.5 %0 kN2250 kN(η = 0.30)-450 kN

1450 kN(η = 0.20)
η : Ratio of the axial force to the compressive
capacity of the first story column
O-1t

Close

Strength of beam-column
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250

36 74 51 78 51 74 36400

152(152 for O-1)

36 50

Hoop
5-D6@40（ 0.80%）

570

450
278

50 36

Horizontal bars
2-D6@100（ 0.64%）Top bars
Stirrup
12-D196-D6@125（ 1.91%）（ 0.38%）

Bottom bars
12-D19（ 1.91%）Figure 4 Specimen O-1t [mm]3. EXPERIMENTAL RESULTS OF SPECIMENS I-1 AND I-1t
The load–drift relationship of I-1 is shown in Fig. 5, where the loading cycles
smaller than 0.5% drift are not shown because the scope of this study is to discuss
the strength and failure mode of the beam-column joints. Blue lines represent thestrengths based on the flexural failure of the first-story column at the beam bottom
face. These strengths are computed using the stress–strain relationship of concrete
proposed by Hognestad et al. (1955). In the opening (positive) direction, during
the cycle to +1% drift, the beam bottom reinforcements and stirrups yielded. The
maximum strength is recorded at +2% drift and corresponds to 66% of thecomputed strength. Figure 7a shows the crack pattern at +2% drift at which the
maximum strength is recorded. A crack in the beam (thick line in Fig. 6a) is
prominent. This crack proceeds to the joint above the hooks of the verticalreinforcement in the extended area of the first-story column. The verticalreinforcements in the second-story column yielded during the cycle to +2% drift(C4 in Fig. 5). In this failure mode as depicted in Fig. 6b, the beam bottom
reinforcements and the vertical reinforcements in the second-story column are
yielded. In the following, the failure associated with the yielding of the beam
reinforcements and vertical reinforcements in the second-story column is calledjoint failure. The arrows in Fig. 6b represent the sign of the bending moments ofthe first-story column (Mc1), the beam (Mb), and the second-story column (Mc2).
The bending moment of the second-story column is opposite to that in the usual
beam-column joints. Therefore, the force-resistant mechanism of this joint isdifferent from that of the usual beam-column joints. The failure mode ofSpecimen I-1 in the opening direction is a joint failure and it has large ductility.
The strength remains almost constant up to +5% lateral drift.
In the closing direction, during the cycle to -2% drift, the beam-top
reinforcements yielded (B4 in Fig. 5). Figure 7a shows the crack pattern at −2%drift. In addition, the lateral strength degraded during this cycle as shown in Fig. 5.

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The compressive failure of the wall panel was observed. As discussed above, theforce-resistant mechanism of this joint is different from that of the usual beamcolumn joints; the failure of the wall panel triggered strength degradation (see thephoto in Fig. 7a). An inclined crack in the beam is prominent in the closing
direction. On the basis of these results, as shown in Fig. 7b, the failure mode
corresponds to the joint failure, which is a brittle failure mode, and the lateral loaddecreases rapidly when the wall panel fails under compression (Fig. 5).
The load–drift relationship of I-1t is shown in Fig. 8. In the opening direction, thevertical reinforcements in the first-story column yielded prior to the beam bottom
reinforcements during the cycle to +1% drift. The maximum strength is recorded
at +2% drift, which corresponds to 92% of the analytical strength based on the
flexural capacity of the first-story column. In the closing direction (the left half ofFig. 9), the vertical reinforcements in the first-story column yielded during thecycle to −1% drift. The yielding of the beam-top reinforcements and thecompressive failure in the wall panel are not observed in I-1t. The specimen I-1t
has large ductility in the closing direction as well as in the opening direction.
800

Load (kN)

▲

▲

400

Test result
Analytical strength
Maximum strength
Bar yielding

Opening▲

B1,B2 C4 +436kN
S1,B3

0
Closing

B4

-400

S1
C4

-800
C5

B4 ▲ -950kN

C5

B1 B2 B3

-1200
-5

-4

-3

-2

-1
0
1
Lateral drift (%)

2

3

4

5

Figure 5 Load-drift relationship of I-1

Mc2
4.0
3.0

Mb

Mc1

(a) Observed damage at +2% drift(b) Failure mode

Figure 6 Failure of I-1 in opening loading
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0.5

Mc2
1.8

Mb

4.0

Mc1

(a) Observed damage at -2% drift(b) Failure mode

Figure 7 Failure of I-1 in closing loading
800

Load (kN)

▲

▲

400

C1 W1
B4
W2
W3

Test result
Analytical strength
Maximum strength
Bar yielding+519kN

C5
C7
H1

C4
H3

Opening0
Closing

W1

-400

W2

S1

-800
C7

-1200
-5

-4

C4

C3
C6
C1(Comp.)
C5 S1 -899kN C2
C8

-3

-2

-1
0
1
Lateral drift (%)

W3 C7
H3
C5

B4
C1

2

3

C8

H1 C6
C2 C3

4

5

Figure 8 Load-drift relationship of I-1t

4. EXPERIMENTAL RESULTS OF SPECIMENS O-1 AND O-1t
The load–drift relationship of O-1 is shown in Fig. 9. In the opening (positive)
direction, during the cycle to +1.5% drift, the beam bottom reinforcements yielded
while the stirrups yielded during the cycle to +2% drift. Figure 10a shows thecrack pattern at +2.5% drift at which the maximum strength is recorded. The threecracks depicted in Fig. 10b are prominent. Therefore, the failure mode in the
opening direction is regarded as joint failure. The strength of the failure is 72% of
the computed strength, but it has large ductility similar to Specimen I-1. The
failure modes of I-1 (Fig. 6b) and O-1 (Fig. 10b) in the opening direction appear
different. However, the strengths of these failures are similar to each otherbecause they are governed by the beam bottom reinforcements and verticalreinforcements in the second-story column, contributing to Mb and Mc2 (Figs. 6band 10b, respectively) as discussed later.
In the closing direction, the beam-top reinforcements yielded during the cycle to−2% drift at which the maximum strength is recorded. Figure 11a shows the crack

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pattern at the maximum strength. The crack at the reentrant corner above the joint
is more prominent than those in the beam and column. Figure 11b shows thefailure mode of the closing direction, which is again a joint failure and has a larger
ductility than that of Specimen I-1 in the closing direction. The compressive
failure of the wall panel was not observed in O-1. The maximum strength of O-1
is also larger than that of I-1 in the closing direction.
The load–drift relationship of O-1t is shown in Fig. 12. In the opening direction,
during the cycle to +1.5% drift, the reinforcements in the first-story column andthe beam yielded. The maximum strength is recorded at +4% drift, which is close
to the analytical strength of the first-story column. In the closing direction, during
the cycle to −1.5% drift, the reinforcements near the reentrant corner above thejoint yielded (B9 and C8 in Fig. 12), indicating joint failure. The maximum
strength is recorded at −2.5% drift and the hoop reinforcements in the upper partof the joint (H3 in Fig. 18) yielded during this loading cycle. During the cycle to−3% drift, the vertical reinforcements in the first-story column (C3) yielded,
indicating column failure.
The failure modes of the specimens are summarized in Table 2. Because the joint
failure of Specimen I-1t is prevented in both directions of the loading, it isconcluded that the stirrups and beam reinforcements increase the strength of thejoint failure of the I-type joints. Because the joint failure of Specimen O-1t isprevented in the opening loading and reduced in the closing direction, it isconcluded that the hoops in the joint and beam reinforcements increase thestrength of the joint failure of the O-type specimen.
800

Load (kN)

▲

▲

0

C1 S1
B2
B3

B1

▲

400

Test result
Analytical strength
Maximum strength
Bar yielding+436kN

Closing

B4

-400

S1
C3

-800
C2

-1200

Opening

B4 ▲ -1065kN

C3

-5

-4

-3

-2

C1
（ Comp.） B1 B2 B3 C1 C2-101
Lateral drift (%)

2

3

4

5

Figure 9 Load-drift relationship of O-1

Strength of beam-column
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Mc2

0.5
0.6

Mb
2.0

Mc1

(a) Observed damage at +2% drift(b) Failure mode

Figure 10 Failure of O-1 in opening loading

Mc2
2.2
1.1

Mb
Mc1

(a) Observed damage at -2% drift(b) Failure mode

Figure 11 Failure of O-1 in closing loading
800

Load (kN)

▲

▲

400
0

+525kN

H1

Test result
Analytical strength
Maximum strength
Bar yielding

C1
B4

Opening
C8

Closing

B9
H3

-400
-800

C3

-1200
-5

-4

C8
C5 B9
C2 -826kN S1
H3

-3

-2

-1
0
1
Lateral drift (%)

2

S1

C5

B4
C1

C2

3

4

H1
C3

5

Figure 12 Load-drift relationship of O-1t

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Table 2 Failure modes of specimens

Specimen

Open

Close

I-1

Joint

Joint

I-1t

ColumnColumn

O-1

Joint

Joint

O-1t

ColumnJoint**The degree of joint failure was reduced andsome symptoms of column failure is observed.

5. STRUT-AND-TIE ANALYSES
Figures 13 and 14 show the strut-and-tie models for I-1 and O-1 specimens. Solidblue lines indicate the bars in the tensile yielding, while dashed lines indicate
below the yield point. Red zones indicate struts in compression. The effective
compression strength of concrete to determine strut’s width is assumed to be 85%of the concrete strength. Because the thickness of the wall panel was 100 mm and1/4 of the width of the beam (400 mm), the width of each strut widens by fourtimes at the boundary of the beam and the wall panel. Similar changes also occur
at the boundary of the beam and the column. The strut distribution agreed with thecrack pattern observed in the test. The lateral load carrying capacity based on
STM agreed with the test result with error less than 10% (Fig. 15).

Figure 13 Strut-and-tie models for I-1 specimen

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Figure 15 Observed strengths vs. strut-and-tie models

6. CONCLUSIONSThe strength of the joints in soft first story is experimentally investigated. Twotypes of joints are tested: 1) first-story column is extended toward the inside of thebuilding (I-type joint; Specimens I-1 and I-1t) and 2) first-story column is
extended toward the outside of the building (O-type joint; Specimens O-1 and O1t). On the basis of the test results, the following conclusions are obtained:
1. In Specimens I-1 and O-1, the failures associated with the yielding of the beam
reinforcements and cracks in the joint (Figs. 7b, 8b, 16b, and 17b) are observed inboth directions of the loading. These failures are called “joint failures.” The

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strengths of these failures are much smaller than those of the flexural strength of
the first-story column.
2. In both types of specimens, the beam-top and bottom reinforcements are
effective to prevent the joint failure in the closing and opening directions,
respectively.
3. The stirrups in the beam are effective to prevent the joint failure of I-type joint.
4. The hoops in O-type joint are effective to prevent the joint failure both in the
opening and closing loads.
5. The observed crack pattern and the strut-and-tie analyses indicate that theforce-resistant mechanisms of these joints are different from those of the usual
beam-column joints because, in contrast with the usual beam-column joints, thesign of the bending moment of the second-story column is the same as that of thefirst-story column.

REFERENCES
Ogawa, T., Teshigawara, M., Ichinose, T., and Kamiya, T., 2012. The effects ofhaunches, axial force and anchorages on the beam-column joint of soft first story.
Transactions of JCI, Vol. 34, No. 2, 269-264 (in Japanese).

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Parametric study for displacement based
analysis of unreinforced brick masonry walls
subjected to lateral loads
Archanaa DONGRE1 and Pradeep K RAMANCHARLA2
1
Associate Professor, Civil Engineering Department, IPEC Ghaziabad,Ghaziabad-201010, India
raut@research.iiit.ac.in
2
Professor of Civil Engineering, Earthquake Engineering Research Centre, IIIT
Hyderabad, Gachibowli, Hyderabad-500032, India
ramancharla@iiit.ac.in

ABSTRACT
Brick masonry construction can be widely seen in Asian countries as well as
globally. Past earthquakes proved the vulnerability of brick houses. Research isgoing on worldwide to understand the behavior of brick masonry buildings.
In this research work, in order to understand the behavior of brick masonrybuildings during earthquake and damage to such buildings, a numerical study isconducted to understand the level of damage by crack occurrences, theirevolution, block separation and material loss before collapse and mitigation
measures of retrofitting of weak buildings can be suggested. In this parametricstudy; three cases have been considered i.e. Effect of mortar volume, effect ofspan ratio and effect of opening on strength and stiffness of wall.
Keywords: Displacement based analysis, mortar volume, span ratio

1. INTRODUCTION
Masonry buildings are brittle structures and one of the most vulnerable whencompared with the all building types under strong earthquake shaking. Groundvibrations during earthquakes cause inertia forces at locations of mass in thebuilding. These forces travel through the roof and walls to the foundation.
Masonry building consist of three main components i.e. wall, roof and foundation,in which walls are most vulnerable to damage caused by horizontal forces due toearthquake. As, during earthquake ground shakes simultaneously in vertical aswell as horizontal direction and horizontal vibrations are the most damaging tonormal masonry buildings. Horizontal inertia force developed at the roof transfers
to the walls acting either in the weak or in the strong direction. To ensure goodseismic performance, all walls must be joined properly to the adjacent walls. In
this way, walls loaded in their weak direction can take advantage of the goodlateral resistance offered by walls loaded in their strong direction. Walls also need
to be tied to the roof and foundation to preserve their overall integrity.

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2. NUMERICAL STUDY USING APPLIED ELEMENT METHOD
2.1 Description:
In AEM, structure is assumed to be virtually divided into small square elements
each of which is connected by pairs of normal and shear springs set at contact
locations with adjacent elements. These springs bear the constitutive properties ofthe domain material in the respective area of representations (Fig. 1). Global
stiffness of structure is built up with all element stiffness contributed by that ofsprings around corresponding element. Global matrix equation is solved for threedegrees of freedom of these elements for 2D problem. Stress and strain are
defined based on displacement of spring end points of element edges. Details ofApplied Element scheme can be found in literatures by Meguro et al (1998).

Figure 1. Element shape, contact point and degrees of freedom(Meguro et al, 1998)
2.2 Discretization for brick masonry:
Anisotropy of the masonry is accounted by considering masonry as a two phasematerial with brick units and mortar joint set in a regular interval. Structure isdiscretized such that each brick unit is represented by a set of square elements
where mortar joints lie in their corresponding contact edges (see Figure 2).
In spring level, springs that lie within one unit of brick are termed as ‘unit springs’.
For those springs, the corresponding domain material is brick as isotropic natureand they are assigned to structural properties of brick. Springs those accommodate
mortar joints are treated as ‘joint springs’. They are defined by equivalent
properties based on respective portion of unit and mortar thickness. Figure 2
shows the configuration of brick units, joints and their representation in this study.
The initial elastic stiffness values of joint springs are defined as in Eq. 1 and 2(Bishnu, 2004).

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Figure 2. Masonry discretization: Details of brick unit spring and mortar joint spring

K nunit =Eu t dEu Emt d; K njo int =a
Eu x t h + Em (a − th )(1)

K sunit =Gu t dGu Gmt d; K sjo int =a
Gu x t h + Gm (a − th )(2)

Where Eu and Em are Young’s modulus for brick unit and mortar, respectively,
whereas Gu and Gm are shear modulus for the same. Thickness of wall is denotedby ‘t’ and ‘th’ is mortar thickness. Dimension of element size is represented by ‘a’and ‘d’ is the fraction part of element size that each spring represent. Whileassembling the spring stiffness for global matrix generation, contribution of all
springs around the structural element are added up irrespective to the type ofspring. In the sense, for global solution of problem, there is no distinction ofdifferent phase of material but only their corresponding contribution to thestiffness system.
2.3

Masonry material model

Material model used was a composite model that takes into account of brick andmortar with their respective constitutive relation with elastic and plastic behaviorof hardening and softening. Brick springs were assumed to follow principal stressfailure criteria with linear elastic behavior. Once there is splitting of brickreaching elastic limit, normal and shear stress are assumed not to transfer throughcracked surface in tensile state. The brick spring’s failure criterion is based on a
failure envelope given by Eq. 3:

fb ft
+ =1
fb. ft '(3)

Where fb and ft are the principal compression and tensile stresses, respectively, andf’b and f’t are the uniaxial compression and tensile strengths, respectively.

Parametric study for displacement based analysis of unreinforced brick masonry walls
Parametric study for displacement based analysis of unreinforced brick masonry walls
subjected to lateral loads
subjected to lateral loads

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Figure 3: Cohesion degradation(Bishnu Pandey, 2002)

Figure 5: Failure criteria for joint spring(Sutcliffe et al, 2001) (Lourenco, 1996)

Figure 4: Bond degradation(Bishnu Pandey, 2002)

Figure 6: Hardening andsoftening applied for joint springin compression cap (Lourenco,
1996)

Coulomb’s friction surface with tension cut-off is used as yield surface after
which softening of cohesion and maximum tension takes place in exponential
form as a function of fracture energy values and state variables of damage. The
cohesion and bond values are constant till the stress first time when stress exceeds
the respective failure envelopes. Figure 3 and 4 shows the degradation scheme ofbond and cohesion. Failure modes that come from joint participation of unit andmortar in high compressive stress is considered by liberalized compression cap asshown in Figure 5. The effective masonry compressive stress used for cap mode
follows hardening and softening law as shown in Figure 6. The tension cut-off, f1,
and the sliding along joints, f2, exhibit softening behavior whereas thecompression cap experiences hardening at first and then softening. The failuresurfaces used in this study derived from Lourenço, (1997), with some
simplification are as given in Eqs. (4), (5) and (6). (Figure 5)
 f
f1 (σ , K1 ) = σ − ft exp  − tI K1 
(4)
 G

f


 c

f2 (σ , K2 ) = τ + σ tan(φ1 ) − c exp  − II K2 
(5)
 G

f


f3 (σ , K3 ) = τ + σ tan(φ2 ){(σ 3 (K3 ) − σ )}(6)
In above equations, K1, K2 and K3 are hardening and softening parameters fortension, shear and compression behavior respectively. GIf and GIIf is fractureenergy in tension and shear respectively.

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2.3.1 Material model for concrete and steel:As a material modeling of concrete under compression condition, Maekawa
compression model (Okamura and Maekawa, 1991), as shown in Figure 7 (a), is
adopted. The tangent modulus is calculated according to the strain at the spring
location and whether the spring is in loading or unloading process. For moredetails, refer to (Okamura and Maekawa, 1991). After reaching the peakcompression stresses, stiffness is assumed as a minimum value (1% of initialvalue) to avoid having a singular stiffness matrix. The difference between
calculated spring stress and stress corresponding to the strain at the spring location
are redistributed each increment. And for shear springs, model is assumed. Till thecracking point stresses are assumed to be proportional to strains and after thatstiffness is assumed as minimum value (1% of initial value) to avoid having a
singular stiffness matrix. For reinforcement, bilinear stress strain relation isassumed. After yield of reinforcement, steel spring stiffness is assumed as 1% of
the initial stiffness as shown in Figure 7(b). No model is used, up to this stage, forcut of reinforcement because the behavior of the structure becomes mainly
dynamic behavior and the static stiffness matrix becomes singular.
It should be emphasized that some other failure phenomena, like buckling of
reinforcement and spalling of concrete cover, are not considered in the analysis in
this analysis. However, the shear transfer and shear softening are approximately
considered in the analysis. For more details about material models used and theresults in case of monotonic loading conditions, refer to [Meguro and Tagel-din,
2001](a) Concrete in Tension and compression(b) SteelFigure 7: Material models for concrete and steel

3. PARAMETRIC STUDY OF URM BUILDING USING AEM
Description of geometry: Building considered for the analysis is as shown in
Figure 8. Building height is 4m and width is 3.9m. Column and beam crosssection is considered as 0.3m X 0.3m. Reinforcement is provided as per therequirement. Brick wall panel has dimension of 3.3m X 3.7m X 0.3m. Brick size
is considered as per the local brick in practice. In this study, initially a framedwall building (see Figure 8) with reinforcement (see Figure 9 (a) and (b)) is
considered and it has been studied under displacement control cases for
Monotonic static condition. Displacement control is capable to give the response
Parametric study for displacement based analysis of unreinforced brick masonry walls
Parametric study for displacement based analysis of unreinforced brick masonry walls
subjected to lateral loads
subjected to lateral loads

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October 2013, Hanoi, Vietnam
0ctober 2013, Hanoi, Vietnamof building in post yield. Response of the Infill wall in terms of Base shear
versus drift ratio is plotted and structures behavior is studied through this response.
Loading Parameters: A displacement control technique for monotonic staticcase has been considered, as this method is capable of giving post peak behavior.
A lateral displacement of 0.02m is applied in 100 increments on the wall.
Geometry boundary conditions and loading are as below:
Geometry:

4.0m

3.9m
Figure 8 Numerical model of brick infill wall

(a)

(b)

Figure 9: Reinforcement details for (a) Beam (b) Column
Boundary conditions: Base elements are considered as fixed
Loading: Displacement control used. 0.02m displacement applied in 100 loading
steps.
3.1 Parameters Considered: Three parametric studies have been considered inthis analysis. i.e. Effect of span ratio, effect of opening and mortar volume.
3.1.1 Effect of span ratios: In order to study effect of wall span ratio (h/w) on
strength of the wall, four cases have been considered in this analysis as shown in
Figure 10. Span ratio (h/w) of 0.5, 1.0, 2.0 and 4.0 is considered and displacementof 0.02m is applied laterally in 100 increments.
Geometry, boundary conditions and loading are as given below:
Geometry: Geometry is as shown in Figure 10
Boundary conditions: Base elements are considered as fixed
Loading conditions: Displacement control used.0.02m displacement applied in
100 loading steps

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Effect of aspect ratio can be observed in above Figure 11. Aspect ratio of 0.5
shows more loads carrying capacity than other cases; this is due to high stiffnessof wall pertaining to less aspect ratio. Shear is predominant in this case. Case 2
having aspect ratio 1 shows lesser load carrying capacity than case 1, as in thiscase though shear is predominant but stiffness of wall is less when compared tocase 1 due to high aspect ratio. Strut action can be observed in this case. Case 3

Case 1h/w = 0.5

Load (kN)

Case 2
Case 3
Case 4h/w = 2h/w = 4h/w =1Figure 10: Cases considered for understanding effect of Aspect ratio

0

0.002

0.004

0.006

0.008

0.010
0.012
Displacement (m)

0.014

0.016

0.018

0.02

Figure 11. Effect of aspect ratio on wall strengthshows lesser load carrying capacity as aspect ratio is higher at 2, still shear is
predominant in this case, but strut action cannot be observed here. Case 4 shows
very less load carrying capacity as in this case bending is predominant. In suchcases provision of horizontal bands should be considered to avoid weaker sections.
From this analysis, It is understood that with increase in aspect ratio, load carrying
capacity of the wall decreases (see Figure 11)
Parametric study for displacement based analysis of unreinforced brick masonry walls
Parametric study for displacement based analysis of unreinforced brick masonry walls
subjected to lateral loads
subjected to lateral loads

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October 2013, Hanoi, Vietnam

Load (kN)

3.1.2 Effect of openings
In order to understand the effect of opening on behavior of wall, an Infill wall ofsize 3.9m X 4.0m is considered in the analysis. Five cases were considered for the
study. In first case, full infill wall without opening is considered. In second case,
opening in the centre of wall has been considered. In third case, door opening inleft side is considered whereas in fourth case door opening in the middle has been
considered. In fifth case lintel has been provided on door opening.
Geometry, boundary conditions and loading are as given below (Figure12 and
13):
Boundary conditions: Base elements are considered as fixed
Loading: Displacement control used.
0.02m displacement applied in 100 loading steps.
Details of opening:
Case 2: Central opening of size 1.2m X 1.2m
Case 3: Door opening of size 1.0m X 2m
Case 4: Door opening of size 1.0m X 2m
Case 5: Lintel of size 75mm provided. Main reinforcement in Lintel is of 2-8mm
dia. bars and hooks of 6mm dia. used.
Figure 12 shows base shear versus drift ratio relation for the four cases considered.
It can be clearly seen that infill wall without opening having more load carrying
capacity due to more strength and stiffness of wall when compared with othercases. For second case of central opening shows lesser load carrying capacity thanother cases. In this case, at first diagonal zigzag cracks arise along opening incompression diagonal, as loading increases these cracks progress further. As shear
is predominant in this case, central opening in wall makes it weaker.

0

0.002

0.004

0.006

0.008

0.010
0.012
Displacement (m)

0.014

0.016

0.018

0.02

Figure 12. Effect of opening on capacity of wall

For case 3 and 4, positioning of door is considered in left side and in the middle.
In case 3, at the initial stages of loading wall shows better load carrying capacity(270kN) as opening does not fall in the middle of the tension diagonal but in laterstages stiffness of the wall is continuously decreasing due to weaker pier at left
side where stresses are more at the base. Whereas in case 4, as opening is in the248

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middle, cracks initiated in the left diagonal at first due to which load carrying
capacity can be seen less initially in Figure 12, but as loading increases, load is
distributed in both the piers which makes wall to carry more load (310kN), but atlater stage decrease in strength and stiffness can be seen due to progressing cracks
in piers due to tensile stresses.
3.1.3 Effect of Mortar Volume
Boundary conditions: Base elements are considered as fixed
Loading: Displacement control used.
0.02m displacement applied in 100 loading steps.
Overall four cases have been considered:
Case1: Brick size 0.21m X 0.10m X 0.07m with mortar thickness 10mm
Case2: Brick size 0.21m X 0.10m X 0.07m with mortar thickness 20mm
Case3: Brick size 0.40m X 0.20m X 0.10m with mortar thickness 10mm
Case4: Brick size 0.40m X 0.20m X 0.10m with mortar thickness 20mm
Mortar thickness is considered as 10mm and 20mm respectively for the brick sizeof 0.21m X 0.10m X 0.07m. In case 1, mortar volume accounts as 0.448m3 andfor case 2 it is 0.630m3 this due to high mortar thickness considered in this case.
Considering high mortar thickness actually reduces strength of the wall, as mortar
being weaker bond in the wall, further increase in thickness increases weaker zone
in the wall which reduces strength of the wall. Case 3 and 4; mortar thickness is
considered as 10mm and 20mm respectively for the brick size of 0.40m X 0.20m
X 0.1m. In case 3, mortar volume accounts as 0.525m3 and for case 4 it is 0.784
m3 this due to high mortar thickness considered in case4.
Table 1 illustrates about mortar volume and brick size considered for each caseand their respective volumetric ratio. For case1 and 3 for different brick sizes withmortar thickness as 10mm volumetric ratio is lesser when compared with case 2
and 4 where mortar thickness is 20mm.
Table 1 Volumetric ratio for masonry and mortar

Cases Brick sizes (m)12
34Mortar Mortar Masonry
thickness Volume Volume
(m3)
(m)
(m3)

0.21 X 0.1 X 0.07 10
0.21 X 0.1 X 0.07 20
0.40 X 0.2 X 0.1 10
0.40 X 0.2 X 0.1 20

0.448
0.629
0.525
0.784

1.324
1.324
1.324
1.324

Volumetric ratio (=
Mortarvolume/Masonry volume)
0.338
0.475
0.394
0.588

Effect of mortar thickness contributes in strengthening of wall. But the mortar
thickness if not considered properly or if considered in higher side then it cancreate a weaker zone in wall, whereas a very thin mortar in brick wall will lead to
improper bonding between the bricks. To understand how the volume of mortar
affects the strength of the wall under loading following study has been done. In
this study, effect of mortar volume on brick masonry wall has been studied byconsidering 2 different sizes of bricks and two different mortar thicknesses. Brick
Parametric study for displacement based analysis of unreinforced brick masonry walls
Parametric study for displacement based analysis of unreinforced brick masonry walls
subjected to lateral loads
subjected to lateral loads249

0ctoberVietnam
October
2013, 2013,
Hanoi,Hanoi,
Vietnamsizes considered were 0.21m X 0.10m X 0.07m and 0.40m X 0.20m X 0.10m andmortar thickness considered were 10mm and 20mm for each case.

4. CONCLUSIONS:
Past earthquake witness most of the disasters in brick masonry building. In viewof this there is a need to study the behavior and damage to brick masonry
structures and to explore the mitigation measures of retrofitting of weak buildings.
In this work, a numerical study has been done to understand the behavior of brickmasonry building. A brick masonry wall is modeled using AEM (Applied element
method) and parametric study has been done by considering different parameters
as, effect of mortar volume, effect of span ratios and effect of opening on strengthof wall. More span ratio is responsible for less strength and vice versa. Effect of
opening makes it difficult to form a diagonal strut action which causes its strength
to degrade with the more opening in the wall. Effect of mortar thickness causes a
weaker zone in masonry wall, so mortar thickness used in construction should beappropriate as per IS code.

REFERENCES
Bishnu Pandey, Meguro, Kimiro, 2004, “Simulation of brick masonry wall
behavior under in-plane lateral loading using Applied Element method”, 13th
World Conference on Earthquake Engineering, Canada.
K.S Nanjunda Rao, IISC Bangalore, 2008, “Structural masonry properties andbehavior” IISC Bangalore seminar
Lourenco and Rots, 1997, “Multi surface interface model for analysis of masonry
structures”, Journal of engineering mechanics, ASCE
Meguro K. and Hakuno M., 1989, “Fracture analyses of structures by themodified distinct element method”, Structural Eng./Earthquake Eng., Japan
Society of Civil Engineers, Vol. 6. No. 2, pp. 283s-294s.
Meguro K. and Tagel-Din H.,1998, “A new simple and accurate technique for
failure analysis of structures”, Bulletin of Earthquake Resistant Structure
Research Center, IIS, University of Tokyo, No. 31, pp. 51-61.
Page, A.W., 1978, “Finite element model for masonry”, J. Struc. Div., ASCE, Vol.
104(8), pp. 1267-1285.
Paola Mayorca, 2006, “Report on the state – of-the art in the seismic retrofittingof unreinforced masonry houses by PP-Band meshes”.
Sutcliffe DJ, Yu H.S, Page AW., 2001, "Lower Bound Limit Analysis of
Unreinforced Masonry Shear Walls." Computer & Structures 2001; (79):12951312

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New Technologies
for Urban
Safetyof MegaA study of the influence of the bending
radius of reinforcement bar on the failure
mechanism of L-shaped beam column joint
by 3D discrete model
1

Kohei NAGAI 1, Liyanto EDDY2, and Koichira IKUTA3
Associate Professor, International Center for Urban Safety Engineering
Institute of Industrial Science, the University of Tokyo, Japannagai325@iis.u-tokyo.ac.jp
2
Doctoral Student, Department of Civil Engineering
The University of Tokyo, Japan
3
Project Engineer, JGC Corporation, Japan

ABSTRACTThe reduction of reinforcement congestion, mainly located in beam column
joints where reinforcements meet from many directions, is required as thereinforcement congestion at beam column joints can cause difficulties during thecompaction of concrete inside the beam column joint during the casting of
concrete, especially when larger bending radius of reinforcement bar is used. On
the other hand, the influence of the reinforcement bar, especially the bending
radius of the reinforcement bar, on the failure mechanism of the beam column
joint has not been clarified well. In this study, in order to reduce thereinforcement congestion at beam column joints, the influence of the bending
radius of the reinforcement bar, on the failure mechanism of L-shaped beamcolumn joints, is investigated. Thus, 3-dimensional models of the L-shaped beamcolumn joints with simple reinforcement bars are simulated by using a discrete
analysis, called Rigid Body Spring Model and the bending radius of thereinforcement bar is varied. Furthermore, the analysis results, including loaddisplacement relationships and crack propagations, are also compared with theexperimental observations. Based on the analysis results, the load-displacement
relationships and the crack propagations are roughly the same with theexperimental investigations. Eventually, based on both the analysis results and theexperimental investigations, it is concluded that the strength of the beam column
joint depends on the bending radius of the reinforcement bar. When a smaller
bending radius of the reinforcement bar is used, the strength of the beam column
joint will be smaller as the compression region inside the radius of thereinforcement bar becomes smaller. Thus, the compressive force will concentratein the small region and causes crushing of concrete.
Keywords: rigid body spring model, L-shaped beam column joint, bending radius,
local failure.

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1. INTRODUCTION
Nowadays, the performance requirements of the building in the seismic code are
more stringent. To satisfy the strict requirement, large numbers of reinforcement
bars must be placed in the reinforced concrete members. As a result,
reinforcement congestion, especially located in a beam column joint where
reinforcement bars of beams are anchored into a column, occurs. Furthermore,
reinforcement congestion may cause difficulties during the compaction of
concrete inside the beam column joint during the casting of concrete, especiallywhen a larger bending radius of reinforcement bars is used.
The requirement of the large bending radius of reinforcement bars is one of thecauses of the reinforcement congestion in beam column joints, particularly whenlarge diameter of reinforcement bars are used. In Japan Code (2007&2011), i.e.
for the beam column joint of viaduct structures, the bending radius ofreinforcement bars is determined by 10 times of the diameter of the embedded
longitudinal bars. However, there is no clarification why the value is determined.
In order to reduce the bending radius of reinforcement bars of beams, a study ofthe influence of the bending radius of reinforcement bars on the failure
mechanism of L-shaped beam column joints, is needed.
Through the experimental work, Yoshitake et al. (2012) studied the effect of thebending radius of reinforcement bars on the failure mechanism of L-shaped beamcolumn joints, and found that both the maximum load and the failure behavior of
the beam column joint will not change as the bending radius of the reinforcement
bars is different. On the other hand, Hotta et al. (2012) also studied the effect of
the bending radius of reinforcement bars on the failure mechanism of L-shaped
beam column joints, and found contrary that both the maximum load and thefailure behavior of the beam column joint will change as the bending radius ofreinforcement bars of beams is different. Thus, the influence of reinforcement bars,
especially the bending radius of reinforcement bars, on the failure mechanism of
the beam column joint has not been clarified well yet. Furthermore, more studies
are needed to clarify the effect of the bending radius of reinforcement bars on the
failure mechanism of L-shaped beam column joints.
Our research groups have used a 3-dimensional discrete analysis, Rigid Body
Spring Model (RBSM), to simulate the behavior of concrete by 3-dimensionalmodels, such as Nagai et al. (2005); Hayashi et al. (2012), and others. In thisstudy, by using Rigid Body Spring Model (RBSM), the influence of the bending
radius of reinforcement bars on the failure mechanism of L-shaped beam column
joints is studied, including the load-displacement relationship, the internal strain
and stress inside the L-shaped beam column joint, and the crack distribution
propagated on the L-shaped beam column joint.
2. ANALYSIS METHOD
In this study, the simulation was carried out by a 3-dimensional discrete analysis,
Rigid Body Spring Model (RBSM), proposed by Kawai et al. (1978). In RBSM, a3-dimensional reinforced concrete model is meshed into some rigid bodies. Eachrigid body consists of 6 degree of freedoms, i.e. 3 transitional degrees of freedom
and 3 rational degrees of freedom within its interior and connects with other rigid
bodies by 3 springs i.e. 2 shear springs and 1 normal spring (Figure 1).

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6DOF
3 SPRINGS
6DOF(a) Model of 3D Re-bar
Concrete Element
Steel Element

Figure 1: Mechanical Model of 3-D
RBSM(b) Cross Section of Elements
Figure 2:
Mesh Arrangements ofConcrete and Re-bar

As the propagation of cracks in the reinforced concrete is one of the mostimportance factors in investigating the behavior of reinforced concrete members,
the mesh arrangement of the model in RBSM is important. In order to prevent
cracks propagated in a non-arbitrary direction, a random geometry, called Voronoi
Diagram, is used for the element meshing. The size of the concrete element was
set to about 1000 mm3, similar to the size of the coarse aggregate. The geometryof steel elements is modeled in an accurate manner, by modeling a 3-dimensionalarrangement of the reinforcement bar, to properly account for the interlock
between the reinforcement bar and concrete. Mesh arrangement of concrete andthe reinforcement bar at meso-scale in this study is shown in Figure 2. To model a3-dimensional reinforced concrete member, two types of elements are used, i.e.
concrete element and steel element. The properties of the spring are determined sothat the elements, while combined together, enable to predict the behavior of themodel as accurate as that of the experimental result. In this study, the simulation
system, developed by Nagai et al. (2005), is used and the constitutive models of
the elements are described below.
2.1 Concrete Element
The constitutive model of a normal spring and a shear spring of the concreteelement is shown in Figure 3. In the compression zone, the normal spring of theconcrete element behaves elastically as crack, between 2 rigid bodies, occurs
when the tensile strength of the normal spring exceeds the tensile strength of theconcrete (ft). After exceeding the tensile strength (ft), the tensile strength of anormal spring is assumed to decrease linearly, depending on the maximum crack
width between 2 rigid bodies (wmax), which is assumed 0.003 mm (see Figure 3(a)).
An elastic-plastic behavior is assumed for the spear spring of the concrete element(see Figure 3(b)), that the value of τmax can be calculated based on equation 1,
adopted from Muto et al. (2004) (see Figure 3(c)). Here, the value of Ф isassumed 37o.
if σ ≥ 0.5 fc(1)
if σ > 0.5 fc
where: c = ft (1-tanФ)Moreover, when fracture occurs in the normal spring, the shear stress is reduced
according to the reduction ratio of the normal stress. As the result, the shear spring
A study
the influencebending radiusof reinforcement
bar on the failure
A study of the influenceof the ofbendingradius ofof thereinforcement
bar onthe failure mechanism
mechanismofL-shaped
beam
columnjoint
by
3D
discrete modelof L-shaped beam column joint by 3D discrete model253

October
2013, 2013,
Hanoi,Hanoi,
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Vietnamcannot carry the stress when the crack width of the normal spring reaches wmax
(see Figure 3(d)).
Generally, the behavior of the normal spring of the interface element, between theconcrete element and the steel element, is assumed to be as same as the normal
spring of the concrete element. Since the behavior of the interface element,
between the concrete element and the steel element is considered more brittle thanthe concrete element, the tensile strength of the interface element is assumed 0.5
times the tensile strength of the concrete element and the maximum crack width
between 2 rigid bodies (wmax) for the interface element is assumed 0.001 mm.
σftτ

Unreload& Reloadτmaxɛ

wmax = 0.003
Controlled by crack width

Compression

Tension(b) Shear Spring(a) Normal Spring

γ

τ

τ
Ф
ft

0.5fc

σ

c
wmax w(c) Failure Criterion(d) Shear Reduction

Figure 3: Constitutive Model of Concrete
2.2 Steel Element
A bi-linear model, both in the compression zone and the tension zone, wasassumed for modeling the normal spring and the shear spring of the steel element.
3. ANALYSIS OF L-SHAPED BEAM COLUMN JOINTS
3.1 Detailed Analysis
In order to clarify the effect of the bending radius of reinforcement bars on the Lshaped reinforced concrete beam column joint, numerical simulations wereconducted for experiments carried out by Hotta et al. (2012) (Figure 4). Since theexperiments were purposed to study the effect of the bending radius ofreinforcement bars on the failure mechanism of the L-shaped beam column joints,

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the bending radius of reinforcement bars in the analysis models was also varied.
In order to reduce the computational time, the model of reinforcement bars of thebeam and the column were simplified. Eventually, the analysis results will becompared with the experimental results.
200

600

500

124

(a) Specimen-1
N

N

V

V

(b) Specimen-2
Figure 4:

Experimental Specimens (Hotta et.al. (2012))

3.2 Analysis Model
The analysis models are shown in Figure 5. Further, the material properties ofconcrete and reinforcement bars are shown in Table 1. The dimensions of the Lshaped beam column joint of analysis models were modeled roughly as same as
those of experimental specimens and the material properties of the analysis
models are as same as those of experimental specimens. The diameter of
longitudinal bars of beams and columns of analysis models is as same as
experimental specimens, i.e. deformed bars of 10 mm. The diameter of transversebars of beams and columns of the experimental specimens, i.e. plain bars of 6 mm,
was changed, becoming deformed bars of 10 mm, due to meshing simplificationin numerical simulation. For easier recognition of the variables in each model, thefollowing notation was used, i.e. C3, C8, C11.5. The number of 3, 8, and 11.5 of
C3, C8, and C11.5, respectively, indicates the bending radius of reinforcement
bars of beams, i.e. 3 times diameter of the embedded longitudinal bars for C3 (30mm), 8 times diameter of the embedded longitudinal bars for C8 (80 mm), and11.5 times diameter of the embedded longitudinal bars for C11.5 (11.5mm). C3 ofthe analysis model represents specimen-1 of the experimental specimen and C8 of
the analysis model represents specimen-2 of the experimental specimen. In order
to simplify the meshing arrangement of the numerical simulation, the bending
radius of Specimen 1 of experimental specimens, i.e. 20 mm, is enlarged into 30
mm for the bending radius of C3 of analysis model. The beam column joint of
C11.5 was only done by the numerical simulation.

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200

Pin
776

80
3D

200

(a) C3776
8D

200

Steel Plate(b) C8

Pin
200
11.5D

80

(c) C11.5
Figure 5: Analysis Models (Units: mm)
Bending
Model

Radius

C3
C8
C11.5

(mm)
30
80
115

Table 1: Material Properties

Concrete Properties
ModulusCompressive TensileofStrength
Strength Elasticity
(MPa)
(MPa)
(MPa)
39.3

2.97

29900

Steel Properties
Modulusof
Yield
No. ofElasticity Stress
Elements
(MPa)
(MPa)
234393190000457
223143217541

3.3 Boundary Condition
The boundary condition of analysis models was modeled as similar as possible tothe experimental set up. Steel plates, located at the end of the beam and thecolumn (Figure 5), were modeled as same as those of the experimental set up(Figure 4). A random meshing was also used for modeling the steel plates. The
stiffness of the steel plates was assumed rigid enough, by increasing the modulus
elasticity of shear springs and normal springs of steel plates, so that the
deformation of steel plates will be prevented. In order to model the hinged
condition of the experimental set up, a pin element is introduced in the analysis
models (Figure 5), located in the middle of the steel plates. Furthermore, in thepin element, forces are transferred only through normal springs of the pin element.
Similarly to the experimental set up, fix condition in all direction was assumed as
the boundary condition of the pin element which is located at the end of the
A study of the Influence of the Bending Radius of Reinforcement Bars on the Failure

Technologies
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256 Mechanism of L-shaped Beam Column JointNew
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column. Moreover, a monotonically displacement-load controlled was applied tothe pin element, which is located at the end of the beam, in a 45-degree diagonal
direction, so that a close mode deformation of beam column joint will occur.
4. ANALYSIS RESULT
4.1 Load-displacement Relationship
Load-displacement relationship of the analysis models is shown in Figure 6.
Load-displacement relationship of the experimental specimens is shown in Figure
7. Furthermore, Table 2 shows the maximum load of the analysis prediction,compared with the experimental observation. The load-displacement relationshipis calculated based on the 45-degree diagonal direction in which direction, load
was applied. The maximum load of the analysis model is roughly as same as thatof the experimental specimens, about 15% difference between the analysis modeland the experimental specimens.
: Specimen 1(2D)Figure6:
Load-Displacement
Relationship of Analysis Models: Specimen 2(8D)Figure7:
Load-Displacement
RelationshipofExperimental
Specimens (Hotta et.al. (2012))

Table 2: The Maximum Load of Analysis Models and Experimental Specimens
Model
C3
C8
C11.5

Maximum LoadExperimental Specimens
Analysis Model
Pexp [kN]
Pana [kN]
38.6
33.6
39.7
38.8
38.9

Pana /Pexp
[%]
87
97.7
-

Based on the experimental observation, the reinforcement bars yield first withoutcausing crush of concrete inside the radius of the bending bar when the maximum
load of Specimen-2(8D) is reached. Therefore, there is no reduction of load
capacity when the displacement is larger than the displacement at the maximum
load. The same behavior was observed by the analysis prediction.
Based on the experimental observation, the compressive failure of concrete occurs
inside the radius of the bending bar, when the maximum load of Specimen-1 (2D)
A study of the influence of the bending radius of reinforcement bar on the failure mechanism
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bar. Therefore, the compressive failure of concrete that occurs inside the radius of
the bending bar, causes the maximum load of Specimen-1(2D) is lower than thatof Specimen-2 (8D). Lower load capacity was observed when the displacement islarger than the displacement at the maximum load.
Based on the analysis prediction, the same diagonal cracks also occur inside theradius of the bending bar as the result of the stress concentration inside the radiusof the bending bar. But, the load capacity of C3 increases as the displacement islarger than the displacement at the maximum load. There are 2 reasons that may
cause the difference behavior between the experimental observation and theanalysis prediction, i.e. the constitutive model of the normal springs of concrete
has not modeled perfectly the compressive softening behavior of concrete and thesimplification of transverse bars of the beam and the column that may cause theshear deformation of the beam and the column is larger than that of experiment.
In addition, in case of C11.5, a beam column joint model that was only done by
the numerical simulation shows the same behavior with C8. Compressive failure
does not occur inside the radius of the bending bar. Therefore, it can be concluded
that after a certain value of the bending radius of reinforcement bars, the stressconcentration will occur inside the radius of the bending bar and further, causes
the compressive failure inside the radius of the bending bar. Moreover, it also canbe concluded that if the compressive failure occurs inside the radius of thebending bar, the maximum load of the beam column joint will be reduced.
4.2 Internal Strain-Stress and Crack Propagation
Stress condition of the beam column joint at the displacement of 2.8 mm andcracks of the beam column joint at the displacement of the maximum load will be
described below. In addition, the displacement of 2.8 mm was chosen, since thedifference of the load-displacement relationships, among C3, C8, and C11.5,
starts to occur when the displacement is larger than this value.
4.2.1 Stress condition of the beam column joint at the displacement of 2.8 mm
Figure 8 shows the internal stress of the analysis model of C3. When a close mode
deformation of the beam column joint occurs, compressive stresses will be
generated along the inner portion of the beam and the column (1) and from thebending part of the reinforcement bars to the corner of the beam column joint (2).
The compressive stresses, which are generated along the inner portion of the beamand the column, were also observed the same in all analysis cases. On the other
hand, the compressive stresses, which are generated from the bending part of thereinforcement bars to the corner of the beam column joint, are different each other,among the analysis model of C3, C8, and C11.5, since the bending radius of thereinforcement bars is also different each other. Furthermore, it is observed that thecompression region of concrete, inside the radius of the bending bar, becomes
smaller when a smaller bending radius of reinforcement bars is used. Furthermore,
the compressive force will concentrate in this small region and causes crushing of
concrete. Because of the difference of stress condition inside the radius of thebending bar, the difference of load-displacement relationship, among C3, C8, andC11.5, starts to occur when the displacement is larger than 2.8 mm.

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1

3Stress-15(MPa)

2

1

3

(a)C3

-15(MPa)

Stress(b) C8(c) C11.5(Deformation × 10)

Figure 8: Internal Stress of C3(Displacement of 2.8 mm)

Figure 9: Internal Stress of Beam Column
Joint Portion of Analysis Models

4.2.2 Cracks of the beam column joint at the maximum load
Figure 10 shows the surface cracks of the analysis model of C3, C8, C11.5,
respectively, at the maximum load.

(a) C3Figure 10:(Deformation × 10)(b) C8(c) C11.5

Surface Cracks of the Analysis Models

Based on surface cracks of the analysis model of C3 (Figure 10 (a)), cracks
propagate easily inside the radius of the bending bar, as the result of thecompressive stress concentration inside the radius of the bending bar. On the other
hand, based on surface cracks of the analysis model of C8 and C11.5 (Figure10(b) & Figure 10(c)), more cracks propagate outside the radius of the bending
bar. It is also observed that many shear cracks occur on the surface of the beamand the column as the result of the simplification of the transverse bars of thebeam and the column.
Figure 11 shows the internal cracks of the analysis model of C3, C8, C11.5,
respectively. Based on internal cracks of the analysis model of C3 (Figure 11(a)),
compressive cracks propagate inside the radius of the bending bar. On the other
hand, based on the internal cracks of the analysis model of C8 and C11.5 (Figure11(b) & Figure 11(c)), no compressive crack was observed inside the radius of the
A study of the influence of the bending radius of reinforcement bar on the failure mechanism
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bending bar and flexural cracks propagate at the beginning of the bending portion.
Thus, the same behavior as the distribution of surface cracks was observed.

: Crack width = 0.03 mm(b) C8(a) C3Figure 11:(c) C11.5

Internal Crack of the Analysis Models

Figure 12 shows the surface cracks of the experimental specimen of Specimen-1(2D) & Specimen-2(8D), respectively. The crack propagation of the experimental
specimens was observed roughly as same as that of the analysis models, i.e.
compressive cracks propagate inside the radius of the bending bar when a smaller
bending radius of reinforcement bars is used, however, no compressive crack was
observed inside the bending radius of the bending bar and flexural cracks
propagate at the beginning of the bending portion when a larger bending radius ofreinforcement bars is used. Therefore, the crack propagation of the analysis modelis roughly as same as that of experimental specimens and the analysis results can
explain well why both the maximum load and the failure behavior of beamcolumn joint will change as the bending radius of reinforcement bars is different.

(a) Specimen-1 (2D)
Figure 12:(b) Specimen-2 (8D)

Surface Cracks of the Experimental Specimens

A study of the Influence of the Bending Radius of Reinforcement Bars on the Failure

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5. CONCLUSION
Based on the numerical simulation using a three-dimensional discrete analysis
method, 3-dimensional Rigid Body Spring Model (RBSM), the reinforcement
bars in the L-shaped beam column joint, especially the bending radius of thereinforcement bars, affects the failure mechanism of the L-shaped beam column
joint.
Thus, the following conclusions are made.
1. 3-dimensional discrete analysis method can simulate well the failure
mechanism of the L-shaped beam column joint with simple reinforcement.
The analysis explains well the failure mechanism inside the beam column
joint.
2. By the numerical simulation, the dimension of the bending radius ofreinforcement bars affects the failure mechanism of the L-shaped beamcolumn joint. In addition, when a smaller bending radius is used,compressive failure occurs inside the radius of the bending bar and further,decreases the maximum load of the beam column joint. On the other hand,when a larger bending radius is used, the reinforcement bar at the
beginning of the bending portion yields and flexural failure may occur atthe beginning of the bending portion. The same behavior was also foundby the experimental observation.
3. By the numerical simulation, the dimension of the bending radius ofreinforcement bars affect the internal strain and stress inside the beamcolumn joint, the crack propagation on the surface of the beam column
joint and the crack propagation in the beam column joint. When a smaller
bending radius is used, the compressive force is concentrated inside theradius of the bending bar and further, local failure will occur. On the other
hand, when a larger bending radius is used, the compressive force may
distribute well in the larger area of compression zone and further, local
failure will not occur.
REFERENCES
Japan Society of Civil Engineering, 2007. Standard Specification for Concrete
Structures.
Concrete Technical Series, 2005. Design System of Reinforced Concrete
Structure –Back to the Future-.(in Japanese)
Yoshitake, K., Ogawa, A., Ogira, D., and Maezono, T., 2012. The Effect of Bond
Behavior of Longitudinal Reinforcement of Beam and Column on Beam Column
Joint. JCI Vol.34, No.2, pp. 541-546. (in Japanese)
Hotta, H., Nishizawa, N., 2012. An Experimental Study on the Effect of the
Position of Longitudinal Reinforcement for Reinforced Concrete Beam-Column
L-shaped Joint. JCI Vol.34, No.2, pp. 282.83-282.88. (in Japanese)
Nagai, K., Sato, Y., and Ueda, T., 2005. Mesoscopic Simulation of Failure ofMortar and Concrete by 3D RBSM. Journal of Advanced Concrete Technology
Vol.3, No.3, pp. 385-402.

A study of the influence of the bending radius of reinforcement bar on the failure mechanism
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Yoshitake, K., Ogawa, A., and Ogira, D., 2010. Bond Performance ofLongitudinal Reinforcement of Column and Beam at Joint Part Considering
Positional Relation. JSCE Vol-555, pp. 947-948. (in Japanese)
Hayashi, D., Nagai, K., Yoshitake, K., and Ogura, D., 2012. Assessment of theEffect of the Reinforcement Spacing on Bond Performance by 3D-RBSM. JCI
Vol.34, No.2, 559-564. (in Japanese)
Kawai, T., 1978. New Discrete Models and Their Application to Seismic
Response Analysis of Structure. Nuclear Engineering Design. 48. pp.207-229.
Muto, S., Worapong, S., Nakamura, H., 2005. Investigation of Bond Behavior ofDeformed Bar by Meso Scale Simulation. JCI Vol. 27, No.2, pp. 763-768. (inJapanese)

A study of the Influence of the Bending Radius of Reinforcement Bars on the Failure

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262 Mechanism of L-shaped Beam Column JointNew
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Discrete ModelAn experimental investigation of a selfoscillating multi-heat pipe using pure waterand alumina nanofluid, respectively
Danh Tung DAO 1,3, Shuichi TORII2
PhD student, Kumamoto University, Kumamoto, Japan
daodanhtung@gmail.com
2
Professor, Kumamoto University, Kumamoto, Japan
3
Lecturer, National University of Civil Engineering, Ha Noi, Viet Nam
1

ABSTRACTThis experimental study is performed to investigate heat transfer performance of aself-oscillating multi-heat pipe in the condition of different fill charge ratios anddifferent constant heat fluxes. In this experiment, pure water and alumina (Al2O3)
nanofluid are employed as the working fluid, respectively. The heat pipe iscomposed of an evaporator section, a condenser section and an adiabatic section.
The evaporator and condenser sections have the same size and are connected byfour circular parallel tubes. The corresponding external dimensions are 45mm inlength, 45mm in width and 8mm in thickness, and the internal dimensions are
42mm, 42mm and 5mm, respectively. The adiabatic section is consisted of fourparallel circular tubes whose dimension is φ6 (external diameter) x φ5 (internal
diameter) x 45 (length) mm. A series of experiments with different fill charge
ratios and constant heat fluxes were carried out to measure temperature of theheat pipe. It is found that: this self-oscillating multi-heat pipe has capability
increasing heat transfer performance corresponding with the increase of heat
flux; With this type of heat pipe, from 30% to 100% of fill charge ratio at 10%
intervals of working fluid, when applied low heat flux until 10W/cm2, the higher
the fill charge ratio is, the higher the heat transfer performance is. When applied
higher heat fluxes 15W/cm2 and 20W/cm2, the highest effective thermal
conductivity of the multiple-heat pipe appears around 40% of fill charge ratio; theheat transfer performance of this self-oscillating multi-heat pipe is enhanced
when working fluid – pure water is replaced by alumina (Al2O3) nanofluid 0.1%.
Keywords: Heat transfer performance; self-oscillating multi-heat pipe; working
fluid; alumina nanofluid; fill charge ratio; effective thermal conductivity

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1. INTRODUCTION
One of the most common cooling devices is heat pipe. It works based on boilingheat transfer and condensation heat transfer principles. Working fluid inside theheat pipe absorbs heat and boils at a certain pressure value in the evaporator
section. After boiling, working fluid becomes vapor and evaporates to thecondenser section and the vapor releases latent heat to this section and iscondensed to working fluid again. After that, working fluid travels back theevaporator section with the use of capillary forces in a wick or gravitational,
centrifugal, electrostatic, and osmotic forces. The two-phase closed thermosyphon
is one of types of heat pipe using gravitational force. It is a simple, but effective
heat transfer device. Due to its high equivalent axial thermal conductivity, andcost effectiveness, it has been used in many applications, such as: preservation
permafrost, de-icing roadways, turbine blade cooling, and applications in heatexchangers - Faghri [1995].
There were studies that investigated the heat transfer capability of the two-phaseclosed thermosyphon. S.H. Noie [2005] studied experimentally the effects of
input heat transfer rates (100 to 900W at 100W intervals), the working fluid filling
ratios (30%; 60%; 90%) on the heat transfer characteristics of a two-phase closed
thermosyphon. Yong Joo Park et al. [2002] investigated experimentally the heattransfer characteristics of a two-phase closed thermosyphon on the effects of fillcharge ratio 10-70% at 10% intervals and heat flow rate 50-600W … It can beconcluded from literatures that the different fill charge ratios and different heat
fluxes have effects on the heat transfer performance of the two-phase closed
thermosyphon. Wei Guo and Darin W. Nutter [2009] had a deep study andshowed the results of an experimental study of axial conduction through athermosyphon pipe wall. The experimental data showed that the conduction
through the pipe wall caused the wall temperature to decrease along theevaporator section. It also increases the overall heat transfer coefficient,evaporation heat transfer coefficient, and condensation heat transfer coefficient of
the thermosyphon. However, the heat transfer associated with axial conduction
decreased as the heat flux increased.
With the same purpose to develop heat pipe, this study developed andinvestigated a self-oscillating multi-heat pipe with a very simple structure (Fig. 2).
In addition, the heat pipe was investigated with the application of new class fluid nanofluid.
Modern technology makes it possible to produces particles < 100 nm indiameter for suspending in conventional fluids such as water, engine oil, andethylene glycol. This new class of fluids is referred to as "nanofluids". Whoseterm is first named and used by Choi [1995]. Compared with micron-sizedparticles, nanoparticles have much larger relative surface areas and a great
potential for heat transfer enhancement. Based on this idea, many studies wereconducted to explore superior properties of nanofluids, such as large surface-areato-volume ratio, stable suspension, and no flow passage clogging, which aresuitable in heat transfer applications. This is because the much larger surface areasof nanophase powders relative to those of conventional powders not only
markedly improve conduction heat transfer capabilities but also increase thestability of suspensions. Eastman et al. [1996] demonstrated that oxide
nanoparticles such as Al2O3 and CuO have excellent dispersion properties in

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water, oil, and ethylene glycol and form suspensions. Lee et al. [1999] measured
thermal conductivity of fluids containing Al2O3 and CuO particles so that for thecopper oxide/ethylene glycol system, thermal conductivity can be enhanced bymore than 20% at 4 vol %. In particular, they disclosed that the thermal
conductivity of nanofluids depends on that of both the base fluids and particles.
Lee and Choi [1996] estimated the performance of microchannel heat exchangers
with water, liquid nitrogen, and nanofluids as the working fluid and showed thesuperiority of nanofluid-cooled microchannel heat exchanger. Shuichi Torii and
Wen-Jei Yang [2009] also demonstrated the superior property of nanofluid thatsignificant enhancement of heat transfer performance due to suspension of
nanodiamond particles in the circular tube flow is observed in comparison withpure water. Tun-Ping Teng et al. [2010] studied about effect of alumina nanofluid
particle size on thermal conductivity and showed that adding nanoparticles to
fluid can effectively increase the thermal conductivity ratio of the fluid. Applying
nanofluid to heat pipe, S.H. Noie et al. [2009] studied about heat transfer
enhancement using Al2O3 nanofluid in a two-phase closed thermosyphon (TPCT)and the results showed that nanofluids of 1%, 1.5%, 2%, 2.5% and 3% have better
thermal performance than pure water. They improved efficiency of the TPCT up
to 14.7%. Temperature distributions on the TPCT were lower level using
nanofluid compared to pure water. Temperature differences between theevaporator and condenser sections with nanofluid were less than that of purewater.
Based on the foregoing good results of researchers about application of nanofluids
to heat exchanger, in this research, Al2O3 nanofluid was also applied to the selfoscillating multi-heat pipe to study the heat transfer performance with different
fill charge ratios and different constant heat fluxes. The particles used here were
Al2O3 size less than 30 nm diameter. The base working fluid is pure water.

2. EXPERIMENTAL APPARATUS AND METHOD
2.1 Experimental apparatus
A schematic diagram of experimental apparatus is described in Fig 1. In thisfigure, the self-oscillating multi-heat pipe was made in Laboratory of Kumamoto
University – Japan, the heat pipe was heated on the evaporator section by theheater block made by copper containing 5 heaters (HAKKO) inside with the useof thermo-glue (AINEX) between two surfaces to improve heat transfer (5 heaters
are not shown in this figure). 5 heaters were connected with the transformer(YAMABISHI) and its voltage and power were measured by the digital multimeter (AC/DC POWER HITESTER 3334). The transformer was connected withpower supply in the Laboratory. An adequate amount of pure water was filled
inside of the self-oscillating heat pipe by the burette (NALJENE). Vacuum
pressure inside the self-oscillating multi-heat pipe was generated by the vacuum
pump (GHD-030) with the measurement by the vacuum gauge (SMC) and thePower indicator transducer (SMC). The condenser section of the heat pipe wascooled by cooling water set at 15oC by the thermostatic bath (NCC-1100) with themeasurement of flow by the flow meter (RK400). The temperature of the heatpipe was measured by thermocouples type K with the aid of the data logger
An experimentalof a self-oscillating
multi-heatpipe waterusing pure water and
An experimental
investigationinvestigationof a self-oscillating
multi-heat pipeusing purealumina
nanofluid,
respectively
and alumina nanofluid, respectively

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Vietnam(KEYENCE NR-250) and a personal computer. The working fluids in thisexperimental study were pure water and alumina (Al2O3) nanofluid.

12
13

11

10

17
16

14

20
15
18

9

19
8
6

7

4

3
5

2

1 Data logger
2 Personal computer
3 Digital multimetter
4 Transformer
5 Vacuum valve

6 Burrette
7 Heater block8 Heat pipe
9 Water tank
10 Outlet cooling water1

11 Power indicator for transducer 16 Vacuum valve
12 Pirani gauge Transducer
17 Vacuum pump
13 Vacuum valve
14 Vacuum valve
15 Vacuum valve

18 Inlet cooling water
19 Flow metter
20 Themostatic bathFig.1 Schematic diagram of experimental apparatus
Fig. 2 is detailed drawing of the self-oscillating multi-heat pipe. Duringexperiment, the adiabatic section, the evaporator section and the heater block were
insulated with glass fiber to prevent heat loss, the condenser section was inserted
to a water tank made by plastic containing cooling water flowed circularly fromthe thermostatic bath. In order to fill in the working fluid and make vacuum
pressure, each link part was manufactured.
2.2 Experimental method
In this experiment, the working fluids were pure water and alumina (Al2O3)
nanofluid, respectively. The fill charge ratios fcr between fill charge volume ofworking fluid and internal evaporator section volume were 30%; 40%; 50%; 60%;
70%; 80%; 90% and 100%. The corresponding constant heat fluxes applied to theevaporator section for each case of fill charge ratio were 5W/cm2 (50kW/m2);
10W/cm2 (100kW/m2); 15W/cm2 (150kW/m2) and 20W/cm2 (200kW/m2). The
angle between heat pipe axis and vertical direction was 0o (Fig. 3a). As shown in

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Fig. 2, the temperature of each section of the heat pipe was measured withthermocouples type K as follows: for the evaporator section: point H1, H2, H3, H4,
H5; for the condenser section: point C1, C2, C3. The inlet temperature of thecooling water was set at 15oC using the controllable thermostatic bath and coolingwater was supplied to the water tank at a rate of 3.5l/min. After filling an adequate
amount of working fluid in the heat pipe, the vacuum pressure would be generated
by vacuum pump and its value was maintained at 7400 Pa for all cases. In order to
get accurate vacuum pressure value, the vacuum pressure value was read on the
power indicator transducer after 20 minutes and when changing from one fillcharge ratio to another, the working fluid was filled in when whole experimental
system was 25oC. Temperature was measured until the experiment reached steadystate and the steady state time was at least 30 minutes. After finishing all
experiments, we could obtain the variation of heat transfer performance of theheat pipe corresponding with the change of the fill charge ratio and heat flux andtwo results between the use of pure water and nanofluid were compared
A

45
42

8

Cooling part
1.5

C1
1.5

42

C3

10
φ6

φ6

φ6

φ6

φ5

φ5

φ5

φ5
45

Four tubes

10

135

7.5

45

1.5

C2

Heating part

10

H2
H5

1.5

45

42

H1

H3

H4

8

42

A

45

A

A

Fig.2 Structure of the self- oscillating heat pipe

An experimentalof a self-oscillating
multi-heatpipe waterusing pure water and
An experimental
investigationinvestigationof a self-oscillating
multi-heat pipeusing purealumina
nanofluid,
respectively
and alumina nanofluid, respectively

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3. EXPERIMENTAL RESULTS AND DISCUSSION
3.1 The effect of fill charge ratio and heat flux on the temperature of the heatpipe
Fig. 3b shows how the temperature changes in the evaporator section and thecondenser section at fill charge ratio from 30% to 100%.

x
V ertical direction

TH

TC

y
Fig. 3. a) Vertical direction of the heat pipeb) Temperature form of the evaporator section TH
and the condenser section TC
We can see the temperature changes around a certain value. This can be explained
briefly as follows: when the heat pipe was heated, the temperature of evaporator
section was increased and the working fluid became vapor and it would be
evaporated to the condenser section. The evaporator section reached the highest
temperature until the working fluid film refluxed and cooled it. When the vapor
met the condenser section, it would transfer latent heat to the condenser section
and then condensed to working fluid again. Therefore, the temperature of thecondenser section would be increased. When the condensed fluid traveled backdown the evaporator section, it would absorb heat from the evaporator section anddid make the temperature of the evaporator section decreased. At the same time,
the condenser section was cooled by circulated cooling water contained in watertank.
Figs.4 and 5 show the effect of fill charge ratio on mean temperatures of theevaporator and condenser section of the heat pipe with the use of pure water andalumina nanofluid 0.1% volume fraction, respectively. To get mean temperature
TH of the evaporator section and TC of the condenser section, local temperatures
were measured and averaged. With the measurement by thermocouples type K,
points H1, H2, H3, H4 and H5 are for the evaporator section and C1; C2; C3 are forthe condenser section. These points were depicted in Fig. 2.
TC + TC 2 + TC 3
TH + TH 2 + TH 3 + TH 4 + TH 5
TH = 1; TC = 1. As shown in Figs. 45
3
and 5, we can see that the variation of mean temperature of the evaporator andcondenser section corresponding with the increase of fill charge ratio in two casesof working fluid is similar. Mean temperature of the evaporator section tends todecrease corresponding with the increase of fill charge ratio. For the condenser

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section, the variation trend has a difference, which is mean temperature also has
trend to decrease corresponding with the increase of fill charge ratio, however, at
40% of fill charge ratio, temperature of the condenser section get maximum value
when heat flux goes up. From this phenomenon, it can be guessed the heat pipe
reaches the maximum of heat transfer performance at 40% of fill charge ratio
when applied much much higher heat flux.
Also from this results, we can see that with the same heat flux and fill charge ratio,
mean temperature of the evaporator section of the heat pipe using Al2O3 nanofluid
0.1% Vol is lower than that of using pure water. In contrast, mean temperature of
the condenser section of the heat pipe using Al2O3 nanofluid 0.1% Vol is higher
than that of using pure water. This demonstrates an excellent sign for this heatpipe when applied nanofluid as working fluid.

Fig.4 Mean temperature of the evaporator section
versus fill charge ratio with the use of pure water and Al2O3 nanofluid 0.1% vol

An experimentalof a self-oscillating
multi-heatpipe waterusing pure water and
An experimental
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multi-heat pipeusing purealumina
nanofluid,
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Fig.5 Mean temperature of the condenser section
versus fill charge ratio with the use of pure water and Al2O3 nanofluid 0.1% Vol
3.2 Heat transfer characteristic of the self-oscillating heat pipe
Effective thermal conductivity keff of the heat pipe was calculated as follows:
Q = NAq' = NAkeff

TH − TC
L

QL
k eff =NA (TH − TC )

(1)
(2)

Where, Q is total heat load (W), q’ is the heat flux from the evaporator section to
the condenser section (W/mK), L is the length from center of the evaporator
section to center of the condenser section (m), that is the approximate distance
between TH measuring point and TC measuring point. N is the number of tubes of
the adiabatic section (N = 4). A is the flux area of the inner part of a tube in the
adiabatic section (m2).

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Fig.6 Effective thermal conductivity of the heat pipe
versus fill charge ratio with the use of pure water and nanofluid
Fig. 6 shows the variation of effective thermal conductivity keff as a function of fillcharge ratio fcr of the heat pipe with the use of pure water and alumina nanofluid
0,1% volume fraction, respectively. As shown in Fig. 6, we can see that at
5W/cm2 and 10W/cm2 of heat flux, in both cases of working fluid, effective
thermal conductivity of the heat pipe tends to increase when fill charge ratio
increases, in other word, the higher the fill charge ratio is, the higher the effective
thermal conductivity is. However, from 15W/cm2 and over, the relationshipbetween effective thermal conductivity of the heat pipe and fill charge ratio isdifferent. Namely at 15W/cm2 of heat flux, the effective thermal conductivity of
the heat pipe still increases corresponding with the increase of fill charge ratio, but
the maximum effective thermal conductivity occurs at 50% of fill charge ratio. At
20W/cm2, the relationship between effective thermal conductivity of the heat pipeand fill charge ratio is inverse, the effective thermal conductivity of the heat pipe
tends to decrease when the fill charge ratio increases, and the maximum effective
thermal conductivity occurs at 40% of fill charge ratio. This can be explained thatwhen heat flux applied to the evaporator section of the heat pipe increases andexceeds a certain value, a high amount of heat from the evaporator section istransferred through the wall of the heat pipe to the condenser section and makes itreaches high temperature even when it was being cooled by cooling water. In
addition, with a high amount of working fluid inside the heat pipe fcr = 100%, ityields too much vapor when working fluid evaporated and this causes lack of
inner space in the heat pipe and condensation temperature of vapor will be
increased. Therefore, heat transfer efficiency is decreased. In other words, hightemperature at the condenser section combines with much vapor makes
condensation performance decreases and this corresponds with the decrease ofheat transfer performance.
Also from this figure, it is easy to see that with the same heat flux and fillcharge ratio, the effective thermal conductivity of the heat pipe with the use of
An experimental investigation of a self-oscillating multi-heat pipe using pure water andalumina
nanofluid,ofrespectively
An experimental
investigationa self-oscillating multi-heat pipe using pure waterand alumina nanofluid, respectively

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4. CONCLUSION
From the observation of the results in this study, the following conclusions are
drawn:
With the conditions of the experiment• With this type of heat pipe, from 30% to 100% of fill charge ratio at 10%
intervals of working fluid, when applied low heat flux until 10W/cm2, thehigher the fill charge ratio is, the higher the heat transfer performance is.
When applied higher heat fluxes 15W/cm2 and 20W/cm2, the highest
effective thermal conductivity of the multiple-heat pipe appears around
40% of fill charge ratio.
• This self-oscillating multi-heat pipe has capability increasing heat transfer
performance corresponding with the increase of heat flux.
• The heat transfer performance of this self-oscillating multi-heat pipe isenhanced when working fluid – pure water is replaced by alumina (Al2O3)
nanofluid 0.1%.

REFERENCES
A. Faghri,. 1995. Heat pipe science and technology, Taylor & Francis.
S.H. Noie,. 2005. Heat transfer characteristic of a two-phase closed thermosyphon,
Applied Thermal Engineering 25 495 - 506.
Y.J. Park, H.K. Kang, C.J. Kim,. 2002. Heat transfer characteristic of a two-phaseclosed thermosyphon to the fill charge ratio, International Journal of Heat andMass Transfer 45 4655-4661.
Wei Gue, Darin W. Nutter,. 2009. An experimental study of axial conduction
through a thermosyphon pipe wall, Applied Thermal Engineering 29 3536 - 3541.
Choi, S.U.S.,. 1995. Enhancing thermal conductivity of fluids with nanoparticles,
in Developments Applications of Non-Newtonian Flows, FED-vol. 231/MD-vol.
66, ASME: 99-105, edited by D.A. Siginer and H. P. Wang. New York.
J. A. Eastman, Stephen U. S. Choi, Shaoping Li, L. J. Thomson, and Shinpyo Lee,.
1996. Enhanced thermal conductivity through the development of nanofluids,
Proceedings of the Symposium on Nanophase and Nanocomposite Materials II,
Material Research Society, Bonton, MA, pp. 3-11.
S. Lee, Choi, S. U. S., S. Li, and J. A. Eastman,. 1999. Measuring thermal
conductivity of fluids containing oxide nanoparticles, Journal of Heat Transfer
121 280 - 289.
Lee, S.P., and Choi, U.S., 1996. Application of metallic nanoparticles suspensionsin advanced cooling system, in: Y. Kwon, D. Davis, H. Chung (Eds.), Recent
Advances in Solid/Structures and Application of Metallic Materials, PVPVol.342/MD-Vol.72, The America Society of Mechanical Engineering, New York,
pp. 227-234.
S. Torii, W.J. Yang,. 2009. Heat transfer augmentation of aqueous suspensions of
nanodiamonds in turbulent pipe flow, Journal of Heat Transfer 131 043203-1-5

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T.P. Teng, Y.H. Hung, T.C. Teng, H.E. Mo, H.G. Hsu,. 2010. The effect ofalumina/water nanofluid particle size on thermal conductivity, Applied ThermalEngineering 30 2213-2218.
S.H. Noie, S. Zeinali Heris, M. Kahani, S.M. Nowee,. 2009. Heat transfer
enhancement using Al2O3/water nanofluid in a two-phase closed thermosyphon,International Journal of Heat and Fluid Flow 30 700-705.

An experimentalof a self-oscillating
multi-heatpipe waterusing pure water and
An experimental
investigationinvestigationof a self-oscillating
multi-heat pipeusing purealumina
nanofluid,
respectively
and alumina nanofluid, respectively

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Earthquake behavior of reinforced concrete
framed buildings on hill slopes
Ajay K SREERAMA1 and Pradeep K RAMANCHARLA2
1
Ph.D Student, Civil Engineering, IIIT Hyderabad,
Gachibowli, Hyderabad-500032, India
ajay.s@research.iiit.ac.in
2
Professor of Civil Engineering, Earthquake Engineering Research Centre, IIIT
Hyderabad, Gachibowli, Hyderabad-500032, India
ramancharla@iiit.ac.in
ABSTRACT
Recent earthquakes, 18 Sep 2011, Sikkim earthquake, M6.9 and 1 May 2013 Doda
earthquake, M5.8 produced two major effects, namely on buildings and on hillslopes. The maximum intensity of ground shaking experienced during theseearthquakes was only about VI or less on the MSK scale. Considering the low
intensity of ground shaking in the affected areas, the damage attributed wasdisproportionately higher. It is mainly due to high amplification in local site areas.
In this regard, a research is carried out to understand the performance ofbuildings on hill slopes.
In this paper, the study of the behavior of a G+3 building on varying slope angles
i.e., 15°, 30°, 45° and 60° is studied and compared with the same on the flatground. Building is designed as per IS 456 and later subjected to earthquake
loads. It was observed that as the slope angle is increasing, building is becoming
stiffer. Two types of analyses were conducted viz., lateral load analysis andincremental dynamic analysis. It was observed from the initial results that thecolumns on the higher side of the slope i.e., short columns were subjected to moreshear force then longer columns on the lower side. Finite element method is used
to study the static behavior where as Applied Element Method (AEM) is used toperform incremental dynamic analysis.
Keywords: hill-slopes, incremental dynamic analysis
1. INTRODUCTION
North and northeastern parts of India have large scales of hilly terrain, which are
categorized under seismic zone IV and V. In this region the construction ofmultistory RC framed buildings on hill slopes has a popular and pressing demand,due to its economic growth and rapid urbanization. This growth in construction
activity is adding to tremendous increase in population density. Whileconstruction, it must be noted that Hill buildings are different from those in plainsi.e., they are very irregular and unsymmetrical in horizontal and vertical planes,275

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and torsionally coupled. Since there is scarcity of plain ground in hilly areas, itobligates the construction of buildings on slopes.
Recent earthquakes i.e., 18 Sep 2011, Sikkim earthquake (M6.9) and 1 May 2013
Doda earthquake(M5.8) produced two major effects, namely on buildings and on
hill slopes. To perform well in an earthquake, a building should possess four main
attributes i.e. simple and regular configuration, adequate lateral strength, stiffnessand ductility (as per clause 7.1 of IS 1893-2002).
1.1. SEISMIC BEHAVIOUR OF BUILDINGS ON SLOPES IN INDIA
Shillong Plateau earthquake (M8.0) of 1897 and the Kangra earthquake (M7.8) of
1905, were the major of several devastating earthquakes to occur in northern India.
An estimated of more than 375,000 population were killed in epicentral region,and over 100,000 buildings were destroyed by the earthquake. Similarly in recent
earthquakes like Bihar-Nepal (1980), Uttarkashi (1991), Sikkim (2011), and Doda
(2013) affected many buildings on hill slopes.
India having a great arc of mountains consisting of the Himalayas defines thenorthern Indian subcontinent. These were formed by the ongoing tectonic
collision of the Indian and Eurasian plates where housing densities ofapproximately 62159.2 per Sq Km are around as per 2011 Indian census. Hence
there is a need to study on the seismic safety and design of these structures onslopes.
Dynamic characteristics of hill buildings are significantly different from thebuildings resting on flat topography, as these are irregular and unsymmetrical inboth horizontal and vertical directions. The irregular variation of stiffness andmass in vertical as well as horizontal directions, results in centre of mass andcentre of stiffness of a storey not coinciding with each other and not being on a
vertical line for different floors. When subjected to lateral loads, these buildings
are generally subjected to significant torsional response. Further, due to site
conditions, buildings on hill slope are characterized by unequal column heights
within a story, which results in drastic variation in stiffness of columns of thesame storey. The short, stiff columns on uphill side attract much higher lateralforces and are prone to damage.

Figure 1: An aerial view of houses located on hill slopes in Sikkim

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2. CASE STUDY AND ANALYSIS
A five different cases of G+3 buildings on varying slope angles i.e., 0°,15°, 30°,
45° and 60° are designed and analyzed as per IS 456 in SAP2000 as shown in
Figure 2 and 3. The properties of the considered building configuration in thepresent study are summarized below.
Structural element sizes

Beams :
Columns:
Slab :

300 x 300 mm
300 x 300 mm
120 mm thickMaterial properties
Grade of concrete:
Grade of Steel reinforcement bars:

M25
Fe 415

Live load:
Floor finish load :Self-weight of slab :3 kN/m2
1kN/m2
3kN/m2

Loading

4@
3000 mm

Col 1

Col 2

Col 3

Col 4

Col5

4 @ 3000 mm
Figure 2: G+3 RC framed structure (Reference building)
The building has been subjected and analyzed for earthquake load i.e., N90E
component of Northridge ground motion with a PGA of 0.565g and magnitude
M6.7.

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Table 1: Buildings considered for study: Details of 5 buildings
Number
Bottom column lengths (m)of bays
Buildi
Description(Both
Col Col Col Col Col
ng
direction
1
2
3
4
5
s)
A

G+3 Regular building
(0°)

4

3

3

3

3

3

B

G+3 building on 15°
slope

4

6.2

5.4

4.6

3.8

3

G+3 building on 30°
slope

4

9.92

8.19

6.46

4.73

3

D

G+3 building on 45°
slope

4

15

12

9

6

3

E

G+3 building on 60°
slope

4

23.8

18.6

13.4

8.2

3

C

Two types of analyses were conducted viz., lateral load analysis and incremental
dynamic analysis. It was observed from the initial results that the columns on thehigher side of the slope i.e., short columns were subjected to more shear force
then longer columns on the lower side. Finite element method is used to study thelinear and non linear static and dynamic behavior of building on slopes, where as
Applied element method is used for incremental dynamic analysis.

30°
30
°

Figure 3: Model of Building on slope

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3. RESULTS AND DISCUSSION
From the linear static analysis it is observed that the Shorter Columns is observed
to take more loads since shorter columns are stiffer and hence has more stresscarrying capacity. From Figure 4 column 1 is observed to have base reaction
reduced to zero as slope angle increase because of long column effect.

Col 4

Col 5

Col 3
Col 2
Col 1

Figure 4: Base reaction Vs Slope
3.1. DYNAMIC CHARACTERISTICS OF BUILDING
An inertia force is caused due to the oscillation of building during an earthquake,where it is foremost for us to understand the mode of oscillation i.e., Natural
period and deformed shape. Numerical results are used to study the dynamic
behavior and the factors that influence it.
Table 2: Natural time period of Buildings on varied slope angles
0°

15°

30°

45°

60°

T1

0.724

0.881

0.994

1.0604

1.1545

T2

0.236

0.276

0.296

0.312

0.343

T3

0.14130.1544

0.159

0.162

0.1691

From table 2, time period of buildings on slopes increase with increase in theslope angle. Since there is an increase in column length of the building thestiffness and mass of it is varying which alters the natural time period. We know
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that time period of structure is directly proportional to both mass and stiffness as
below
T

2



;



k
m

T m

; T

1
k

Stiffness influencing natural period:
Increasing the length of column because of building position on slope decreases
the stiffness and increases mass of the structure. A study has been carried out onbuildings A, B, C, D and E; where the top three storey of the building has same
mass and stiffness, only the bottom portion of the building varies. It has been
observed that due to the increase of column length the building becomes more
flexible with less stiffness. Figure 5 shows the Stiffness degradation of whole
structure as well as the effective stiffness of bottom storey of the structure withrespect to the increase of slope.

Figure 5: % Stiffness Vs Slope
Mass influencing Natural period:
An increase in mass of a building increass its natural period. Buildings B, C, D
and E are with same paln size, column sizes but with different columns length atbottom (Figureure 6). The total seismic mass of the reference building A is1055.12 kN while that in other buildings there is an increase in mass.

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Figure 6: % Mass Vs Slope
3.2. TIME HISTORY ANALYSISThe building has been analyzed for Northridge ground motion with a PGA of
0.565g and magnitude M6.7.

Figure 7: Fourier amplitude of Northridge ground motion
Figure 9 shows the evaluation results of the linear time history responses of thefive buildings. Since the natural frequency of structure is resonating with thepredominant frequency from Figure 8 we can observe the response of building on
60° and 30° slope is observed to have maximum displacement when compared tothat of others. When observed the mass participation of the five buildings we cansay the every structure is predominant in its first mode of vibration. It is also
observed from below plot the storey drift of the building on 45° slope is very lesswhen compared to that of other slope angles.

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Figure 8: Maximum time history response of each storey for five cases

Figure 9(a): Northridge ground motion

Figure 9 (b): Time history response of A, B, C, D and E buildings

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3.3. PUSH OVER ANALYSIS

Figure 10: Pushover curves of A, B, C, D and E buildings
After designing and detailing the RC frame structure, a linear static pushover
analysis is carried out for evaluating structurtal response.Figureure 10 shows theresulting capacity curves for the five cases. Initially they are linear where axial
load is predominant but falls under inelastic range where the flexure and shear
comes into picture. From Figure 10 the area under the pushover curve i.e. thecapacity of building on flat surface is more than that of buildings on slopes.
PLASTIC HINGES MECHANISM
From Figure 11 we can easily observe the formation of hinge mechanism whereas the slope increases the zone near the shoter coulmn is falling under E and D
performance levels, which clearly indictaes the complete collapse of the structure.
Comparision of Figureures b, c,d and e reveals that the pattern of forming hinges
are quite similar. Plastic hinges formation starts with base columns of lower
stories and end beams, then propagates to upper stories and continue with yieldingof intermediate columns.

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0ctober 2013, Hanoi, Vietnam(a) Building A(b) Building B(c) Building C(d) Building D(e) Building E
Figure 11: Hinge mechanism of A, B, C, D and E buildings

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FRAGILITY CURVES
To undertstand the expected damage of the structures of varying time periods,
fragility curves are plotted. Equation used to calculate the damage of the structure
as explained below

Emax = Area under the pushover curve with line dropped parallel to initial stiffness
at the end point.
Ei = Energy dissipated at every displacement (Area under the curve at every
displacement with line dropped parallel to initial stiffness.
Conversion from Roof Displacement to Spectral Acceleration:

Sdi: Spectral Displacement∆roof: Roof displacement obtained from pushover curve
PF1: Participation factors for the first natural mode of the structure
Ø1, roof: Roof level amplitude of the first mode

T: Time Period of the structure
g: Acceleration due to gravity

Figure 12: Fragility Curves

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From Figure 12 we can observe that for a given ‘g’ value the expected damage ismore in 15° and 30° slope buildings than building on falt surface. Whereas thedamage of structure on 45° and 60° slope are less than 15° and 45° because ofincrease in column dimensions, but relatively the damage level is more in 60° thancompared to that of 45° slope building.
3.4. INCREMENTAL DYNAMIC ANALYSIS
To understand and to estimate the structural performance thoroughly underseismic loads a method so called as Incremental dynamic analysis is performed on
to the structures. It involves subjecting a structure to one or more ground motions
scaled to multiples levels of intensity. The main advantage of IDA is that it
addresses both demand and capacity of structure. In the present study Appliedelement method (AEM) is used to perform IDA.
Applied element method is a discrete method in which the elements are connectedby pair of normal and shear springs which are distributed around the element
edges. These springs represents the stresses and deformations of the studied
element. The elements motion is rigid body motion and the internal deformations
are taken by springs only. The general stiffness matrix components corresponding
to each degree of freedom are determined by assuming unit displacement and theforces are at the centroid of each element. The element stiffness matrix size is 6x6.

Figure 13(a): IDA response of the Building on flat surface with spring failure
pattern
In present study Northridge ground motion is scaled to 4 levels i.e. up to 1g andapplied incrementally on to the structures. From Figure 13 we can observe theresponse of the structure increases as the ‘g’ value is amplified. At the end of eachground motion the damage of structure and the spring’s failure pattern can beobserved at the top and bottom of the plot. For building on 45° and 60° slope thestructure is unstable.

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Figure 13(b): IDA response of the Building on 15° slope with spring failure
pattern

Figure 13(c): IDA response of the Building on 30° slope with spring failure
pattern
4. CONCLUSIONSThe study clearly helps us to understand the significant difference between theseismic behaviors of building on slopes to building on flat surface. In summary,the natural period of building depends on the distribution of mass and stiffness
along the building. As the slope angle increases, it is observed that the shortcolumn resist almost all the storey shear since other columns are flexible and tend
to oscillate. A hinge mechanism is formed near the shorter column zone and is

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damaged earlier as the slope angle increases. From the fragility curve we caneasily observe the damage of the structure is more when it is on steep angle.
Major challenge which has to be focused further is considering together plan
irregularity (i.e. Torsional effect) and vertical irregularity. It would be desirable tostudy more cases before reaching some definite conclusions about the behavior ofreinforced concrete framed buildings on slopes.
REFERENCES
1. A.R.Vijaya Narayanan, Rupen Goswami and C.V.R. Murty., 15WCEE
2012 Performance of RC Buildings along Hill Slopes of Himalayas during
2011 Sikkim Earthquake.
2. Pandey A.D, Prabhat Kumar, Sharad Sharma., International Journal of
Civil and Structural Engineering Volume 2, No 2, 2011 Seismic soilstructure interaction of buildings on hill slopes.
3. B.G. Birajdar, S.S. Nalawade., 13WCEE 2004 Seismic analysis ofbuildings resting on sloping ground.
4. ATC 40, Seismic evaluation and Retrofit of Concrete Buildings, Volume 1.
5. Nicholas A, Roger B., Current science, Vol.79, No.1, 2000., A Note on the
Kangra Ms=7.8 Earthquake of 4 April 1905.
6. Dimitrios Vamvatsikos, C.Allin Cornell., Incremental Dynamic Analysis,
Earthquake Engineering & Structural Dynamics 2002
7. Tagel-Din Hatem, Kimiro Meguro., Applied Element Method for
simulation of Nonlinear materials: Theory and application for RC
structures, Structural Eng./Earthquake Eng., JSCE, Vol 17,No.2,2000

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Using surface roughness as a performanceparameter for RC wastewater pipes
Rahul YADAV 1, Himanshu SINGH 2, Sunil SINHA 3 and Sudhir MISRA 4
1
Former, Graduate Student, Dept of CE, IIT Kanpur, India
2
Final Year Student, Dept of CE IIT Kanpur, India
3
Professor, Dept of CE, Virginia Tech, Blacksburg VA, USA
4
Professor, Dept of CE, IIT Kanpur, India
sud@iitk.ac.in
ABSTRACT
Wastewater concrete pipelines constitute an important part of the undergroundinfrastructure assets, and there is an urgent need to develop reliable tools andparameters to quantitatively understand and predict the performance of thesepipes, which deteriorate under the action of wastewater, groundwater, etc.
Effort in this work was directed to study changes in the surface characteristics ofconcrete specimens drawn from normal RC wastewater pipes subjected toaccelerated deterioration under the action of artificial sewage (biogenic sulfide).
The water-cement ratio of the concrete was kept at two levels and the exposure
media was prepared from sulfate reducing (SR) media with cow dung as thesource for SR bacteria. The samples kept at room temperature in sealed plastic
boxes, were removed at designated times for investigation and were studied
visually before a more detailed investigation was carried out at a few locations.
Results from the preliminary studies suggest a definite possibility of usingchanges in roughness of RC pipes as an indicative parameter for forecasting theirperformance in the field, and, that (a) both the water cement ratio and exposure
duration affected the surface characteristics of the concrete, (b) more changes inthe surface roughness were found in cases when the water-cement ratio washigher, and, (c) samples drawn from concrete having a higher water-cement ratio
had higher instances of ‘tuberculation’ on the surface.
Keywords: Reinforced concrete, sewage, deterioration, surface roughness,
infrastructure monitoring
1. INTRODUCTION“The Energy and Resources Institute in New Delhi has estimated that by 2047,
waste generation in India's cities will increase five-fold to touch 260 million
tonnes per year”- Acharya, 2012289

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamWith this kind of demand, there is a huge pressure on existing wastewater
pipelines in urban areas and the Municipal Corporations face an infrastructure
crisis requiring renewal of pipelines, which in most of the cases is beyond theircapacity. A schematic variation of the present worth of replacement, repair andtotal costs is shown in Figure 1. It is clear that ‘waiting till failure’ approach is
economically not viable, as the optimal time to replace the pipe is when the totallife cycle cost reaches its minimum, besides the fact that that approach has several
other implications as well.

Figure 1: Economic Breakdown Even Analysis of a Pipeline
In order to tackle the demand for adequate maintenance of wastewater pipelines, arobust mechanism that assists in their condition evaluation and prediction, risk
analysis, and renewal prioritization, is urgently needed. Monteny, et al., (2001)
found that in many places in sewer pipes, sulfuric acid causes degradation of
concrete. Hudon, et al. (2010) found that (a) bio-deterioration of concrete starts
initially with pH decrease by carbon dioxide and hydrogen sulfide gases, which
also react with cement paste, and, (b) microorganisms facilitate formation of
sulfuric acid which attacks concrete. Ayoub, et al. (2004) conducted hydrogensulfide assessment in cementitious sewer pipes and concrete culverts (morethan 30 years old) in four major cities and found that only a negligible amount ofsulfide was generated and also at a very slow rate.
2. BACKGROUND
In a wastewater RC pipe, a sulfur cycle is formed due to bacterial and chemical
activity leading to the formation of sulfuric acid as can be seen in Figure 2, which
is a schematic representation of the inside conditions. Sulfur is a substrate formany thiobacilli such as Thiobacillus thiooxidans, Thiobacillus neapolitanus, andThiobacillus intermedius (Kelly, 1982; Hazeu, et al., 1988). In anaerobic
conditions (due to long retention time or slow flow of the sewage), sulfate
reducing bacteria, e.g., Desulfovibrio, reduce sulfur-compounds to H2S, which
may react with oxygen to precipitate elemental sulfur on the sewer wall (Vincke,

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2009). The CO32-, HCO3- in the water or CO2 in the air react with Ca(OH)2 in the
cement paste to generate calcite, a reaction that decreases the alkalinity of thecement paste and threatens decomposition of the calcium silicate hydrate (CSH)
gel in the hydrated paste. The sulfate and carbonate erosion products react with
the CSH gel in the presence of excess water to generate thaumasite[Ca3Si(OH)6(CO3)(SO4).12H2O] (Yang & Yang, 2012). Ultimately, the cement
hydrates in the concrete structures are gradually broken down forming the erosion
products of gypsum, ettringite, calcite and thaumasite.

Figure 2: Schematic representation of processes in a sewer pipe
(Adapted from Hudon, et al., 2010)

3. EXPERIMENTAL DETAILS
3.1 Test programme
Experiments were carried out using concretes having two water-cement ratios(45% and 55%), with the changes in the specimens being recorded at 15, 30 and
90 days of exposure for 45% and 15, 30 and 45 days of exposure for 55%. The
specimens were closely scrutinized visually and the roughness measured using
surface profiling. Though chemical analysis using concrete powder drawn fromthe surface was also carried out, the results have not been reported here.
3.2 Preparation of concrete test specimens
Special effort was made to keep the effect of manufacturing method andworkmanship to a minimum. The concrete specimens were drawn from pipes
manufactured in a factory using the normally used material and methods, with________________________________________________________________________
Using surfaceUsing
roughnessa performanceparameter for
RC wastewater
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only the proportions being decided according to the requirement of this research
project and given in Table 1.
Table 1: Materials required to make the pipes
Materials
Cement Content
Coarse Aggregates (FM = 3.4)
Fine Aggregates (FM = 2.19)
Water Content
Chemical Admixture

Quantity (kg/per pipe)
0.45 w/c ratio
0.55 w/c ratio
200
200
546.12546.12303.60303.6090 litres
110 litres
1
1

The following steps were followed in obtaining the specimens used for testing:a) Casting and curing of pipes – The concrete was mixed manually (as is thepractice in the plant), and cast into 500mm long pipe segments conforming
to Class NP3 (IS 458:2003) with internal diameter as 1000 mm having awall thickness as 115 mm. The reinforcement in the pipes was kept in the
middle of the wall. After feeding the concrete, the internal surface wasfinished with cement slurry, as per the usual practice. The pipes were
cured in pond for 8 days before being transported to the laboratory, where
they were left in air during which time the cores were drawn, etc.
b) Drawing and slicing of cores: Several cores (dia: 70 mm, length: 115 mm)
were drawn from along the circumference of the pipes. These cores werethen sliced using a diamond cutter into 20mm thick ‘discs’, to remove thecement finish layer and obtain specimens finally used for exposure. The
process is schematically shown in Figure 3.

Figure 3: Schematic representation of process of obtaining samples

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3.3 Exposure Media Used
Test samples were exposed to biogenic sulfide environment created using sulfate
reducing media and sulfate reducing bacteria (SRB), sourced from cow dung,which was easily and freely available.
Table 2: Composition of sulfate reducing bacteria enrichment media
Ingredients
Part A
Dipotassium phosphate
Peptic digest of animal tissue
Beef extract
Sodium sulfate
Magnesium sulfate heptahydrate
Calcium chloride

gms/L
0.5
2
1
1.5
2
0.1

Ingredients
Part B
Ferric ammonium
Sodium ascorbate
Part C
Sodium lactate

gms/L
0.392
0.1
3.5

Final pH (at 25°C) : 7.5±0.3a) Details of SRB Media: The sulfate reducing (SR) media used was from the
manufacturer HiMedia Laboratories. The product code for media was M803,
and it came in a triple pack with each designated as part A, B, and C. The
composition of the media is shown Table 2.
b) Preparation of the exposure media for the test specimens: The proceduresuggested by the SR media supplier was adopted in the study. For preparationof 1 litre of SR media, 7.1 grams of Part A was suspended in 900 ml distilledwater, and then sterilized by autoclaving at 15 psi (121°C) for 15 minutes.
Solution of Part B was prepared on the day of use by suspending 0.492 gramsof Part B in 100 ml distilled water. It was then sterilized by filtration througha 0.45 µm membrane filter and this 100 ml solution was added aseptically to
900 ml Part A medium. Then 3.50g of Part C was separately sterilized by
autoclaving at 15 psi (121°C) for 15 minutes and aseptically added to the
mixture of Part A and B and thoroughly mixed. The complete medium was
aseptically transferred to the sterile screw capped tubes. Finally it was purged
with nitrogen gas for 20 minutes before pouring into the test boxes.
c) Source of SR bacteria: Fresh cow dung was used as the source of SRB(Shokes & Moller, 1999). Thus the media for exposure of the concrete
specimens was prepared by mixing the SRB media with SR reducing bacteria.
3.4 Experimental Setup
The discs prepared from the concrete cores (See Figure 3) were immersed in theabove exposure media to study the changes in the concrete undergoing accelerated
deterioration under the action of (artificial) sewage – in the biogenic sulfide
environment created using SR media and bacteria, as described above.
The setup was such that three discs could be placed in a test box, as shown in
Figure 4. To prevent ingress of material from the lateral surface, it was effectively________________________________________________________________________
Using surfaceUsing
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2 liters of SR media along with the SR bacteria, which was derived from about
100g of cow dung added to each box. The three concrete specimens in each box
were tied to a glass fiber rod with the help of glass fiber cloth, which arechemically inert, and held in position during the whole exposure period. The
boxes were sealed and maintained at ambient temperature (30°–35°C) under
Figure 4: Box used for tests showing
concrete specimens held vertically andin position before addition of SR media
and SR bacteria

anaerobic conditions. Five such boxes were used to house a total of 15 specimens
for each of the water-cement ratios. Thus a total of ten test boxes were used.
3.5 Testing procedure
The boxes were opened only at the end of predetermined periods of exposure time
when the concrete specimens were taken out for tests.
a) Numbering of specimens: Specimens made with water-cement ratios 45%
and 55% were stored in separate boxes, and one box of each containing
three ‘discs’ was opened at the end of each of the three exposure periods.
Thus, boxes 45_1, 45_2 and 45_3, for specimens having a water-cement
ratio of 45% were opened at the end of 15 days, 30 days and 90 days,
respectively. Similarly boxes named 55_1, 55_2, and 55_3 were used toobtain specimens having a water-cement ratio of 55% at the end of 15days, 30 days and 45 days, respectively. Suffices a, b and c have been
added to the above to refer to the individual ‘discs’ drawn in each case.
b) Tests carried out: Specimens drawn at the end on an exposure period withlightly washed with tap water, before being carefully observed for changes.
Finally spots were identified on the surface, where ‘profiling’ was carriedout using a 3-D surface profiler (AEP Technology). The contact mode
operation stylus tip diameter was 5 micron. The scanning frequency was
selected to be 35 points per line with the scanning area of 1500*1500
microns as can be seen in Figure 5. Image obtained were processed using
SPIP (Scanning Probe Image Processing)294

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Figure 5: Selection of Scanning Areac) Defining ‘peak distance’ and roughness numbers: Figure 6 shows a schematic
representation of a roughened surface, with a certain profile. With themeasurement of the ‘depth’ of the surface at different points, the peak distance isthe maximum of such measurements and the roughness number is the average ofthe readings, as shown.

Figure 6: Calculating peak distance and roughness values
4. RESULTS AND DISCUSSION
4.1 Effect on pH of exposure media
The pH of the SR media was recorded initially and also at the time of opening ofboxes at different times. The initial pH of all boxes was in the range of 7.26 to
7.34, which changed to slightly more acidic value depending on the duration of
exposure and the water-cement ratio of the concrete specimens in the box (Yadav,2013). This decrease can be attributed to the formation of acidic hydrogen sulfide,
though only a marginal decrease in the pH is seen over the very brief period of
exposure in this study and more data is required to be collected to substantiate thehypothesis.

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4.2 Changes in roughness of concrete surface
Surface profiling at a few places on the mortar phase of the concrete was carriedout in areas measuring 1.5 x 1.5 mm, and the results are discussed here in terms ofthe changes in the peak and average roughness values as defined above. The
results are shown in Figures 6 and 7. The observations made from all the three
discs which had been exposed for the same period are also shown in the figures. A
photographic representation of the observations from the profilometer is given in
Figure 8.
Though there is considerable variation in the observations, as can be seen in the
Figures 6 and 7, which show the values obtained from chosen areas on all thethree specimens (a, b and c, as explained in Section 3.5 above), it can still be
stated that:a) The parameters peak distance and the average roughness can be used as
performance parameters to monitor the changes in the surface condition ofa concrete pipe, as has been done here. They are capable of resolving a
difference on account of parameters such as the water-cement ratio, andmost importantly time. In other words, with sufficient data, a criticalnumber can be defined for these parameters as a threshold before it may beadvisable to actually change a pipe.
b) In the case of both parameters – peak distance and average roughness –there is an increasing trend with exposure period.
c) The increase in both parameters is greater in the case of concrete having a
w/c = 55% compared to result in the case of concrete having a w/c =45%.

50

0.45 w/c Roughness values

0.55 w/c Roughness values
50

40

40

30

30

20

20

10

10

0

0
0

15

30

Exposure Days

90

0

15

30

45

Exposure Days

Figure 6: Variation of roughness values with exposure period

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0.45 w/c peak to peak values

0.55 w/c peak to peak values
500

500

400

400

300

300

200

200

100

100

0

0
0

15

30

Exposure Days

90

0

15

30

45

Exposure days

Figure 7: Variation of peak distance with exposure period
4.3 Visual observations of concrete samples
Visual observation of the concrete specimens in the course of the study showedthat whereas there are no changes in the characteristics of the coarse aggregates,
some sites in the mortar matrix could be identified, where ‘nucleation’ for further
deterioration on account of attack by the sewage was taking place. Representative
photographs of the concrete surfaces are given in Figure 8.

Figure 8: Changes in the roughness of the concrete surface of 45_2_c and
55_3_c; Surface Profile (as imaged from the surface profiling)
5. CONCLUDING REMARKS
Though only limited data has been obtained so far in the research directed atstudying the possible use of changes in surface roughness as a parameter for
deterioration of RC wastewater pipes, the following remarks can nonetheless bemade:________________________________________________________________________
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exposure time.
b) Both, water-cement ratio and exposure duration, affect the surface
characteristics of the concrete in the experiment.
c) The two parameter used in the study – peak to peak distance androughness value can be used to characterize the change in roughness
characteristics of the concrete. Both these parameters indicate an increasein the roughness values with (increase in) exposure time, with greaterchanges being identified in the case of concrete having a higher watercement ratio
Further investigations however, need to be carried to relate remaining service lifeor the need to repair the deterioration of surface in term of roughness. In fact the
problem can be effectively handled only when samples from the field are also
tested for changes in these parameters over time. The present study also suffersfrom an important limitation in that there was no ‘flow’ of the media and therefore
the erosion products could not be (continuously) removed from the system. This
limitation is likely to significantly affect the changes in the pH (of the medium)and also formation of reaction products.
ACKNOWLEDGEMENT
The work reported in this paper was partly supported by the research grant under
the Obama-Singh Knowledge Initiative administered by the Univeristy Grants
Commission of India (Research Project No. UGC/CE/20120147 at IIT Kanpur).
The support is gratefully acknowledged.
REFERENCES
Ayoub, G., Azar, N., Fadel, M. E. & Hamad, B., 2004. Assessment of hydrogensulfide of cementitious sewer pipes: a case study. Urban Water Journal, 1(1), pp.
39-53.
Hazeu, W. et al., 1988. The production and utilization of intermediary elemental
sulfur during the oxidation of reduced sulfur compounds by Thiobacillus
ferrooxidans. Archives of Microbiology, 150(6), pp. 574-57
Hudon, E., Mirza, S. & Frigon, D., 2010. Biodeterioration of Concrete Sewer
Pipes: State of the Art and Research Needs. Journal of Pipeline Systems
Engineering and Practice, 2(2), pp. 42-52.
Acharya, K., August 1, 2012. “India Drowning in Waste, Experts Warn”, Inter
Press Service news agency
Kelly, D., 1982. Biochemistry of the chemolithotrophic oxidation of inorganic
sulfur. Philosophical Transactions of the Royal Society of London. B, Biological
Sciences, 298(1093), pp. 499-528.
Monteny, J. et al., 2001. Chemical and microbiological tests to simulate sulfuric
acid corrosion of polymer-modified concrete. Cement and Concrete Research,
31(9), pp. 1359-1365.

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Shokes, T. E. & Moller, G., 1999. Removal of dissolved heavy metals from acidrock drainage using iron metal. Environmental science \& technology, 33(2), pp.
282-287.
Vincke, E., 2009. Biogenic sulfuric acid corrosion of concrete: microbialinteraction, simulation and prevention.
Yadav, R., 2013, “Condition and Performance Assessment of urban drinking
water and wastewater pipelines”, Thesis submitted to IIT Kanpur in partial
fulfillment of requirements of M Tech degree
Yang, L. & Yang, L.,2012, “Erosion in Weak Sulfate Environment”, Journal of
Civil Engineering and Architecture Concrete.

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Capacity factors for implementing urban
infrastructure projects in India
Yehyun AN1 and Ralph HALL2
Doctoral Candidate, School of Public and Intl. Affairs, Virginia Tech, USA
yehyun@vt.edu
2
Assistant Professor, School of Public and Intl. Affairs, Virginia Tech, USA

1

ABSTRACT
Since the 1950s, Capacity Development (CD) has been one of the most important
items on development agendas. The problem is that the concept has been included
in development projects without due consideration to how it should be applied.
The circumstance of CD for urban infrastructure projects in India is an example
of an application of CD without sufficient review. Recognizing the shortage ofurban infrastructure, the Government of India (GOI) launched Jawaharlal Nehru
National Urban Renewal Mission (JNNURM) in 2005 to provide substantial
central financial assistance to cities over a period of seven years. The GOI
expected the JNNURM to reform institutions and strengthen human resource
capability related to many areas of project delivery. During its implementation,
however, the JNNURM has been confronted by problems relating to a lack of
capacity. This paper reviews the capacity challenges related to the JNNURM
program and considers the broader implications for urban infrastructuredevelopment in India. The paper 1) explores conceptual frameworks of CD byreviewing the existing literature, 2) finds operational elements of the concept
applicable to empirical studies, and 3) determines capacity factors in accordancewith the context of urban infrastructure in India.
Keywords: capacity development, urban infrastructure, project implementation,
JNNURM, India
1. INTRODUCTION
It is estimated that the urban population in India will reach 600 million by 2030,
which is nearly double the urban population of 377 million in 2011 (Planning
Commission 2012). Along with rapid urban growth, socio-economic conditions inurban areas have changed significantly (MOUEPA and MOUD 2005). One
approach adopted by the Government of India (GOI) to manage this rapid
urbanization is the development of urban areas as an accelerator for inclusive
economic development. The Jawaharlal Nehru National Urban Renewal Mission(JNNURM), established in December, 2005, was a first step in realizing thisobjective. This paper covers capacity development challenges related to theprogram with broader implications for urban infrastructure development ingeneral. In the following section, this paper investigates Capacity Development(CD) frameworks provided by international organizations, and reviews the301

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JNNURM in terms of its stated objectives, evaluations, and CD interventions.
Providing an overview of the JNNURM, this paper attempts to articulate thecapacity issues related to urban infrastructure development in India. Considering
the various features of CD, the identified capacity issues are classified into threecapacitylevels:enabling
environment,
organization/network,andindividual/project. Lastly, this paper modifies the CD framework in accordancewith the context of urban infrastructure development in India.
2. CAPACITY DEVELOPMENT
Capacity Development (CD) has its roots in Institution-Building, InstitutionStrengthening, Human Resource Development, and New Institutionalism from the
1950s to 1990s. Each concept has its own objectives and emphasis. Human
Resource Development focuses on the individual, Institution-Building andInstitution-Strengthening approach capacity issues from the perspective oforganizational learning and development, and New Institutionalism highlights thesystem in which organizations operate. CD considers the interdependencies
between each of these levels and utilizes a multiple-level approach, which deals
with specific interventions targeted at a given context. Thus, CD is an umbrella
concept under which various approaches to development are subsumed (Kühl
2009).
The transition through these concepts has been accompanied by an evolution in
the approach to development. Capital-focused development aid needed
institutions to manage funds, which led to Institution-Building and InstitutionStrengthening. Technical assistance and cooperation, which relied on knowledgetransfer, required Human Resource Development in the recipient nations. In the
1980s, New Institutionalism emerged and emphasized a system approach, such as
macro-economic policy and administration improvement.
The classification of capacity reflects its origin, which is derived by combining
various concepts focusing on endogenous forces at different levels. Most literatureuses hierarchical levels of capacity to specify capacity. In spite of minor
differences in the naming of the levels, the levels can be divided into individual,organizational, and environmental levels. It is not possible to offer clear cut
definitions for each of these levels (Pearson 2011). However, there are common
components for each level.
The individual level usually refers to a person’s competencies, including skills
and knowledge. It may also include motivations, attitudes, and personalities thatcan be affected by other higher levels. Second, components shared in an agency or
broad networks of agencies—such as goals, structure, policies, behavioral norms,
partnership, communications, incentive systems, etc.— belong to theorganizational level. At this level, the benefits of the enabling environment are put
into action when a collection of individuals come together (UNDP 2009). Lastly,
the enabling environment contains elements at sub-national, national, regional,
and global levels that are related to broad social systems. This level includes
policies, laws, politics, social norms, cultures, and other important
institutional/environmental factors that form settings where people andorganizations function.

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Capacity interventions should be designed to work within the context in which
they will be deployed. Further, if capacity development initiatives are to achievesustainable results, capacity needs to be considered not just at one level, but interms of the linkages between levels and the complexity of the whole system(Pearson 2011). In other words, the levels are interrelated, and an intervention in
one level may not bring the intended CD results.
Recognizing the lack of a common approach to CD, many development agencies
have developed their own CD framework in order to facilitate a more systemic
process of CD. Even though many differences exist between the frameworks ofthe development agencies, a common feature is that they follow an ‘inputs–
outputs–outcomes–impacts’ model. The frameworks encourage the connection ofchanges in capacity and changes in development results by allowing capacity to
be measured as both a means and as an end. Figure 1 presents the outputsoutcomes-impacts identified by WBI (World Bank Institute) and UNDP (United
National Development Programme). Both agencies imply that changes in outputs
and outcomes can be linked and promoted by specific CD activities. As the twoframeworks show different components in each step, many agencies use
analogous terms for different purposes or in different stages of CD. In other words,
the applications of CD vary widely by different agencies. Consequently, theagencies have flexibility to apply the concept of CD depending on their focus.

Inputs↓

Outputs↓
Outcomes↓
Impacts

WBI
UNDP
Capacity Interventions↓↓

Leaning outcomes:
Raised awareness
Enhanced skill
Improved consensus &teamwork
Fostered coalitions & networks
Formulated policy & strategy
Implemented strategy & plan

Change in Capacity Level
across Core Issues:Institutional arrangement
Leadership
Knowledge
Accountability

Capacity factors:
Conduciveness of sociopoliticalenvironment
Efficiency of policy instruments
Effectiveness of organizationalarrangements

Change in
Institutional performance
Institutional stability
Institutional adaptability

Local ownership, effectiveness,
efficiency of resource use↓
Development Goals

Change in people’s wellbeing

↓

↓

↓

↓

Figure 1: Diagrams of Capacity Development Frameworks by WBI and UNDP

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3. JAWAHARLAL NEHRU NATIONAL URBAN RENEWAL MISSION
In 2005, the Government of India (GOI) launched the Jawaharlal Nehru National
Urban Renewal Mission (JNNURM) as a comprehensive package covering
projects, reforms, and CD. In addition to construction projects, state governments
and municipalities were required to implement reforms as a pre-requisite forassistance from central government. The JNNURM has seven mandatory state
reform agendas, six municipal mandatory reform agendas, and ten optional reform
agendas. These reforms are one of the key components emphasized by the GOI,
and are closely related to the empowerment of local government for
decentralization. As a comprehensive package, the JNNURM aimed to implement
programs more efficiently through projects and maintain outcomes for long-run
sustainability through reform(MOUEPA and MOUD 2005).
It is generally believed that the JNNURM has contributed to significant
investments and improvements to the physical infrastructure of cities(Sivaramakrishnan 2011, p.xxv). According to the mid-term appraisal of the GOI,
the program has been achieving its goals effectively. The Planning Commission(2011a) notes that, “the JNNURM has been effective in renewing focus on theurban sector across the country, and has helped initiate a comprehensive processof urban reforms within states and Urban Local Bodies (ULBs)”. Even though the
JNNURM has been somewhat successful in terms of total number of sanctioned
projects and size of allocated funds, many projects and reforms have remained
incomplete. By 2012, only 172 (31 percent) of 551 sanctioned projects werecompleted. 65 percent of the reform agendas were realized, but depending on thestate, the achievement rates vary from 33 percent to 90 percent.
In spite of the positive evaluation, during its implementation, the JNNURM has
been challenged by issues related to a lack of capacity. For example, the mid-term
appraisal notes that “many states and ULBs are facing significant shortages infinancial, social, and governance capacity that limit their ability to steer urban
development and create self-sustaining administrative units at the local level”(Planning Commission 2011a, p.390). The large gap of capacity has beenrecognized as an impediment of the program from the beginning, so the GOI
earmarked 5 percent of the program budget to solve the problem when the
program was designed. However, while the lack of capacity has received
sufficient attention at the central government level, a large portion of the budget
for CD at the local government level remains unspent.
In this regard, many initiatives for CD have been implemented under the
JNNURM to fill the capacity gap by the GOI. The Indian Planning Commission(2011b) reviewed the capacity interventions undertaken by the GOI while creating
the Twelfth Five Year Plan. They found the GOI’s interventions for CD throughthe program to be ad hoc. The commission found that insufficient attention wasgiven to identifying ULBs’ demand for capacity interventions, resulting in a large
gap between demand and supply of the capacity interventions. Further, thecommission found that the capacity interventions were biased towards hard
capacities such as technical skills and knowledge for development results.

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4. IDENTIFYING CAPACITY FACTORSAs explained above, CD is a multi-dimensional concept, and requires a holistic
approach at multiple levels of intervention. In order to investigate capacity in theurban infrastructure sector in India, the capacity gaps at each level need to be
identified. In this section, the capacity factors in the context of the urban
infrastructure sector in India are examined based on the literature of the JNNURM
and expert interviews undertaken by the lead author in October, 2012, in India.
Twenty interviewees from different agencies including major internationalorganizations and local governments participated in an individual interview, anddiscussed issues relating to infrastructure development in India. The interviews
were a semi-structured, open-ended, and face-to-face, and the questions focusedon the participant’s experience, opinion, and knowledge on the following subjects:
1) Identification of capacity gaps for infrastructure development in India; 2)
Status quo of current infrastructure development program; 3) Perspectives onsustainable infrastructure development in India; 4) Evaluation of capacity of the
GOI including local governments for sustainable infrastructure development; and
5) Needs for an alternative capacity development program. The identified factors
from these interviews are described at environment, organization, and individuallevels.
4.1 Enabling Environment Level
This level includes factors related to sub-national and national systems which canencourage or discourage individuals and organizations to demonstrate theircapacity.
Devolution of power to cities
Urban governance in India is described as muddled, ineffective, and nowhere near
ready to face rapid urbanization (MGI 2010). Ineffective governance is closely
related to the lack of capacity of local governments. CEPT University (2012)
states that, “the challenge of urban capacity building is high, not only due to thenumber of staff needs to be trained, but also due to the complexity of institutional
mechanism in city governance”. Concerning the complexity of urban governance,
many studies have referred to nonfulfillment of the 74th Constitutional
Amendment Act (CAA). Municipal institutions in India, so-called ULBs, have a
300-year history (Vaidya 2009). Despite this history, the lack of legal frameworks
for Local Self Government has created a weak structure for decentralization. In
June 1993, the 74th CAA came into force to facilitate decentralization in India.
The 74th CAA has accorded constitutional status to the ULBs to manage urban
governance effectively. However, because devolution is a voluntary-based option,
no state has fully devolved the functions to cities, and although the transfer has
happened on paper, most decision-making power remains with the states (MGI2010). Recognizing the need to facilitate the implementation of the 74th CAA, thecentral government included the fulfillment of the 74th CAA as a mandatory state
reform agenda, and has provided incentives to those states achieving the reforms.
Most literature on the JNNURM (Sivaramakrishnan 2011, Planning Commission
2011b, Vaidya 2009, MGI 2010, Planning Commission 2012) argues thatempowering ULBs through the devolution of functions, functionaries, and funds

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the JNNRUM, there are five agendas related to empowering ULBs—the transferof 12 scheduled functions, the constitution of District Planning Committee (DPC)and Metropolitan Planning Committee (MPC), the transfer of city planning, andmanagement of water supply and sanitation. The achievement rates of the reforms
related to the functions transferred vary depending on the state, and they can beconsidered as one of the enabling environment capacity factors.
Access to human resources
Lack of supply of qualified human resources can be a hindrance for CD. As thepool of human resources increases, local governments have more opportunities to
employ qualified persons. However, in general, the urban sector in India isstruggling with shortage of skilled manpower. For example, MGI (2010) notes
that, “The Ministry of Urban Development (MOUD) estimated that India needsaround 40,000 planners across its cities, while the number of registered planners is
closer to 3,000”. According to Gupta, Gupta, and Netzer (2009), in theconstruction industry, “70-80 percent of the existing workforce is untrained,
which impacts the pace and quality of project implementation, and the situation is
expected to worsen with infrastructure investments driving high growth indemand for skilled manpower”. Hence, the human development level, that
includes literacy and the presence of relevant educational institutions, can have anindirect influence on availability of qualified persons for implementation of the
program.
Other environmental factors
The Enabling Environment level includes policies, laws, politics, social norms,
cultures, etc. Since the JNNURM is a national program, its policies and laws are
fixed. However, some environmental factors are different among states, and many
experts insist that economic (e.g., Gross State Domestic Product), socio-cultural(corruption), and political factors (e.g., political alignment with the central
government) can have influences on the enabling environment indirectly.
4.2 Organization/Network Level
In addition to the typical elements at the organizational level, the complexity ofurban governance can be considered as one of the issues related to the expanded
organizational network.
Institutional structure and involving agencies
In the current institutional structure under the JNNURM, there is considerable
overlap in responsibility for the functions of policy making, regulation, andservice provision (WB 2011), and there may exist fragmentation of
responsibilities without any platform for coordination (MOUEPA and MOUD
2006). The situation relates to the project implementation and service delivery,and has a strong influence on the capacity of local governments.
Sivaramakrishnan (2011) argues that project implementation was entrusted toparastatal agencies thereby “marginalizing the municipalities further”.
In other words, due to the lack of capacity, the ULBs are not fully engaged in
implementation of projects, but the service delivery should be provided by the306

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ULBs, “which often are not financially independent, client-oriented or
professionally specialized” (WB 2011). This ineffective institutional structureoften creates a vicious cycle, and weakens the capacity of the ULBs.
Organizational development strategy
There is a lack of organizational development strategies at the local government
level in India. The lack of organizational development strategies leads to an
absence of formal structures, comprehensive rules, staffing norms, procedures, job
descriptions, pay scales, and the introduction of new technologies (Planning
Commission 2011b). In addition, the absence of organizational systems results in
deficiency in shared values amongst staff, commitment to vision, etc. Moreover,the lack of an organizational system can have a negative influence on capacities atother levels.
Financial viability
One of the main objectives of the JNNURM is to attract investment in urban
infrastructure services. Hence, the JNNURM emphasizes local government’s
financing capabilities. As of September 2010, 36 ULBs were awarded aninvestment grade credit rating, but none of the 36 credit-rate-awarded cities haveborrowed from the market (Sivaramakrishnan 2011). As a result, state
governments and ULBs fell short of their required shares for projects. Thus,
financial viability is closely related to the local governments’ creditworthiness.
Partnership
In the JNNURM, communication channels with the private sector and civilsociety are not very effective (Planning Commission 2011b). The success of cities
like Ahmedabad, Rajkot, and Surat, which have clearly reaped the benefits ofpartnerships at the city level for closing the critical information or knowledge gap,
highlighted the greater needs for “Urban Partnerships” between the cityadministration and various other stakeholders including civil society, academia,
research institutions, media, and private sector (CEPT University 2012).
Accountability
Accountability is one of the critical capacity factors identified by many studies,and most literature on the JNNURM puts emphasis on accountability for better
project implementation and service delivery. From a CD perspective, the focus ison the interface between public service providers and its clients (UNDP 2009). In
the case of the JNNURM, accountability between state governments as oversightbodies and ULBs as responsible bodies and between the ULBs as service
providers and the public as a client can be critical to improving project delivery.
Other organizational factors
The organizational level includes internal structure, internal policies, procedures,
behavioral norms, partnership, etc. One of the key capacity factors identified by
the existing studies is leadership. In India, the recruitment, deployment, andretention system of government officials is not flexible, and is centralized. Thus,
India’s cities at the metropolitan and municipal levels do not have a single-point
empowered leader with tenure to deliver against explicit mandates (MGI 2010).
Hence, the organizations without leadership have less autonomy to pursue

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its mayor or not needs to be considered as a capacity factor at the organizational
level.
4.3 Project/ Individual Level
An urban knowledge needs assessment study by CEPT University (2012)
identified the knowledge gaps and barriers—such as a lack of good engineeringskills and technical know-how, limited awareness, language barriers, poor
computer literacy, over dependence on consultants, etc.—that can be connectedwith capacity at the individual level.
Skill and knowledge gaps
In the current context of rapid urbanization in India, there are many challenges in
the urban sector, and the ULBs will require specialized knowledge andexperiential learning to confront these challenges (Planning Commission 2011).
“Unless the ULBs have skilled manpower to undertake the various additionaltasks entrusted to them” (Vaidya 2009), the actual empowerment and reforms will
not be achieved, and the projects under the JNNURM will face long-termsustainability challenges. Therefore, the skill and knowledge level of the officials
in charge is considered a main capacity factor at the individual level.
Dependence on consultants / Outsourcing
The lack of capacity of local governments in some states causes over-dependency
on consultants. When the JNNURM was launched, the ULBs were expected tolead the preparation of City Development Plans (CDPs) and Detailed Project
Reports (DPRs). However, there were few states in which the ULBs could play amajor role as a planning authority. Regarding this, Sivaramakrishnan (2011) notesthat “in most cases, the municipalities did not understand or discuss the CDPs in
the municipal councils but they were prevailed upon to adopt resolutions
endorsing the CDP prepared so that projects could be submitted to the Centre andfunds obtained” and “consultants were used in preparing or updating or evenpolishing up previously prepared project reports”. The consultants from mega
cities were more equipped with the methodology and techniques of CDP than
ULBs, and there have been sufficient funds to hire the outside consultants. The
availability of funds might have led to an over-dependence on outside consultants,
which meant that ULBs were excluded from the planning process. Through thecase of Patna Municipal Corporation, CEPT University (2012) notes that “overdependence on consultant is blocking the city officials from engaging in
information and knowledge hunting mode”.
Other project factors
Some of the individual factors, such as soft skills, are difficult to measure and set
up criteria to evaluate. However, characteristics of a project may have an
influence on how individuals handle the project. For example, when projects arecomparatively large, use new technology, and involve many stakeholders, the soft
skills that manage the process and engage stakeholders are more critical than forsmall projects. The features of a project can be considered as an indirect capacity
factor at the individual level.

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4.4 Conceptual Framework
Integrating the identified capacity factors, this paper revises the existing CD
frameworks (Figure 2). The modification is based on the following elements toreflect the Indian context:
1) General dimensions of capacity;2) Identified capacity gaps by the GOI’s documents and expert interviews;
3) Formulated CD strategy for JNNURM-II; and
4) Hidden factors which can have influences on CD interventions.
Similar to the existing WBI/UNDP frameworks, this conceptual framework
follows the “input-output-outcomes-goal” model. The input is the CD
interventions by the GOI, and the output is the changes caused by the CD
interventions. The changes will have impacts on the outcomes such as the
project’s implementation, service delivery, and reform achievement. These
outcomes are targeted at meeting the main objectives of the JNNURM.

Impact: Goals of JNNURM
Provision of infrastructure and service
Outcome: Projects and Reforms under JNNURM
Project
Municipal
Service Delivery
Implementation
Reform(Stability)(Performance)(Adaptability)
1HHGV

2EVWUXFWV(IIHFWV

Output: Capacity factors under JNNURM

Organization level:
Enabling
environment level:• Governance• HR supply• Economic factors• Socio-cultural factors• Politics• Institutional structure/

Partnership• Organizational
development strategy• Financial viability/
accountability• Communication/
information• Accountability• Leadership

Individual level:• Skills andKnowledge• Dependency on

consultants

Project factors:•Project budget•Modalities•SectorInput: CD interventions

Figure 2: Capacity Development in the Context of Indian Urban Infrastructure

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5. Conclusion
Many studies have identified the dimensions of capacity to clarify its operational
meaning. As an umbrella concept, CD emerged from a multi-dimensional
approach covering various levels of agency. By reviewing the existing literatureand conducting expert interviews on the JNNURM, this paper presents a
conceptual framework that considers CD at each of the three levels – i.e., enabling
environment, organization, and individual. Operational factors for CD targeted aturban infrastructure development in India are presented.
The identified factors can individually and collectively have influences on projectdelivery and development goals. There have been many studies contributing
theoretical discussions to CD, but few studies apply the theoretical discussions in
empirical ways. In this regard, capacity factors should be examined empirically toconfirm a positive impact on development goals. In addition, there are limited
studies that attempt to evaluate a comprehensive CD approach based on multiple
levels. Since the interaction between different levels is regarded as one of the key
factors for CD, research studying how capacity factors at different levels affectdevelopment goals is needed. By empirically investigating the impact of capacity
factors on project outcomes, better approaches to operationalizing CD can be
developed.
REFERENCES
CEPT University. 2012. Urban Knowledge Needs Assessment. Ahmedabad,
India: Centre for Environmental Planning and Technology University.
Gupta, Prashant, Rajat Gupta, and Thomas Netzer. 2009. Building India Accelerating Infrastructure Projects. Mumbai, India: McKinsey and Company.
MGI. 2010. India's Urban Awakening: Building Inclusive Cities, Sustainaing
Economic Growth. McKinsey Global Institute.
MOUEPA, and MOUD. 2005. Jawaharlal Nehru National Urban Renewal
Mission: Brochure. Delhi, India: Ministry of Urban Employment and Poverty
Alleviation/ Ministry of Urban Development.
MOUEPA, and MOUD. 2006. Jawaharlal Nehru National Urban Renewal
Mission Toolkit. New Delhi, India: Ministry of Urban Employment and Poverty
Alleviation/Ministry of Urban Development.
Planning Commission. 2011a. Mid-Term Appraisal of the Eleventh Five Year
Plan 2007-2012. New Delhi, India: Planning Commission, Government of India.
Planning Commission. 2011b. Report of the working groups for the Twelfth Five
Year Plan (2012-2017). In Housing & Urban Development: Planning Commission,
Governmnet of India.
Planning Commission. 2012. Report of the Committee on JnNURM II: Clean
bastis, safe communities and people's cities. Planning Commission, Governmentof India.
Sivaramakrishnan, K. C. 2011. Re-visioning Indian cities : the urban renewal
mission. New Delhi, India; Thousand Oaks, Calif.: SAGE Publications.
UNDP. 2009. Capacity Development : A UNDP Primer. New York: United
Nations Development Programme.

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Vaidya, Chetan. 2009. Urban Issues, Reforms and Way forward in India. In
Working Paper. New Delhi, India: Ministry of Finance, Government of India.
WB. 2011. INDIA: Capacity Building for Urban Development Project. In
PROJECT APPRAISAL DOCUMENT. New Delhi, India: The World Bank.

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projects in India
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312

New Technologies for Urban Safety of Mega Cities in Asia

Using GFRP for repair and rehabilitation of
RC frames
AMARENDRA 1, Kunwar K BAJPAI 2, Sudhir MISRA 3 and Durgesh C RAI 4
1
Formerly Student, Dept of CE, MNIT, Allahabad, India
2
Senior Scientific Officer, Dept of CE, IIT Kanpur, India
3
Professor, Dept of CE, IIT Kanpur, India
4
Professor, Dept of CE, IIT Kanpur, India
Email for correspondence: kunwar@iitk.ac.in
ABSTRACT
RC buildings are perhaps the most common type of building in urban
areas across the world. In cases of being subjected to earthquake loads, thesebuildings are often damaged near the end of columns due to formation of plastic
hinges, attributed to high bending moments at these regions. Hence, there is aneed to develop a simple and efficient retrofitting technique to restore andpossibly enhance the structural capacity of a damaged building.
Fiber reinforced polymers (FRPs) are emerging as very effective
retrofitting materials due to their superior properties such as low weight and highstrength and easy applicability. In the present experimental study, a damaged RC
frame which was tested under cyclic loading (up to 4.5% drift level) in an earlier
study was used and then retrofitted using glass fibre reinforced polymer (GFRP)
fabrics repaired damaged portions using epoxy mortar. This ‘repaired’ frame wasthen again tested and its stiffness compared by forced vibration and load
controlled slow cyclic tests (Stiffness of damaged RC frame: 1.0 kN/mm; Stiffnessof FRP strengthened RC fame: 3.43 kN/mm). Further the displacement controlled
reverse cyclic tests were repeated up to 4.5% drift level (as per ACI
recommendations) on the FRP strengthened specimen. The test results indicates amarked increase in the performance levels compared to the original specimen
tested up to same drift level.
Keywords: Reinforced concrete frame, earthquake, damage, rehabilitation,
GFRP, stiffness, lateral loading, hysteresis loops
1. INTRODUCTION
Reinforced concrete buildings are most commonly used form of construction inrecent times. RC buildings are generally analyzed such that moment resisting
frames actions are developed in each member. Masonry infill walls are used in RC
frame buildings partition walls and thus are considered as non structural elements
and ignored in analysis and design of RC buildings. However, strength andstiffness of these members play a major role in determining the overall responseof the building during an earthquake.

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Now-a-days almost all the new construction is in the form of RC buildings, ofwhich a large number have open ground story, making them vulnerable toearthquakes. So strengthening of buildings is needed to avoid damage and loss oflife and property. Incidentally, there are few strengthening techniques available toimprove seismic performance of buildings. Many of the existing strengthening
techniques are costly and labor intensive, and often cause reduction in floor area
capacity of the building. Moreover, most of them are not supported by analyticaland experimental investigations.
2. OVERVIEW
Most of the existing structures are not designed as per seismic design provisions
and have abundant deficiencies in their overall configuration. As a result, most of
the RC frames are observed to have inherent deficiencies such as insufficientlongitudinal reinforcement, transverse reinforcement, with wide spacing, open
stirrups and hoops with 90-degree bend, inadequate lap splicing of longitudinal of
longitudinal reinforcement etc (Bai and Hueste 2003). Such buildings are more
prone to severe damages during an earthquake. Generally columns of a non
ductile RC frame suffer more damage under earthquake shaking as compared tobeams due to inadequate lateral load resistance capacities. Most common
observed modes of column failure are in the form of premature shear failure,
brittle crushing of unconfined concrete, reinforcement splice failure near potential
plastic hinge region, shear cracking and column shortening.
Strengthening techniques used can be broadly classified into two groups. First
aims at increasing strength and ductility of concrete section by enlarging theircross-section or by attaching the longitudinal steel plates. Second method aims at
passive confinement to the concrete section due to additional elements to enhancestrength and ductility. Presently the most common retrofitting techniques areconcrete jacketing, steel jacketing and steel caging.
2.1 Concrete Jacketing
Concrete jacketing involves the encasement of RC columns with an additional
layer of concrete and reinforcement cage. Concrete is poured in the formwork
containing newly placed additional reinforcement around the column after thesurface of the column has been roughened by trimming and chipping. In addition
to strengthening columns, this technique is also used to upgrade the beams andbeam-column joints of RC buildings. The construction procedure involves a)
welding of the ends of the jacket stirrups and poured concrete jacket b) welding,ends of Jacket stirrups, dowel placement at the interface and a poured concrete
jacket, and c) bent down bars connecting the jacket bars to the longitudinal bars oforiginal column and a shortcrete jacket. Lateral strength of the columns wasenhanced by jacketing even if there was no treatment at the interface of jacket andold concrete columns.
Concrete jacketing improves seismic resistance of the structural element (CEN,
2005). However, increase in the lateral stiffness of the strengthened structural314

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system can attract more seismic forces (Wu et al., 2006). The main disadvantage
of concrete jacketing is that it is labour intensive and causes reduction in usable
floor area due to significant increase in size and self weight of jacketed column
system. Ferro-cement jacket has been considered as an alternative to strengthen
the RC columns of inadequate shear strength and ductility. Ductility of RC
columns is increased by providing external confinement over the entire height.
Ferro-cement jacketing with expanded meshes produce distributed fine shear
cracking at large displacement ductility level.
2.2 Steel Jacketing
To improve the lateral strength, stiffness and ductility of deficient columns, steeljacketing is the most common technique. In this method wrapping of steel plates,
strips or bars in the transverse directions of column sections is done after removalof damaged concrete cover. The main advantage of steel jacketing over concrete
jacketing are relatively less increase in the column section, speed of fabrication,
lower cost and interruption of use of structure, and also relatively less increase in
the stiffness.
Steel jackets can also be pre-stressed in the hoop direction to improve the concreteconfinement in the columns. The pre-heated jackets are used prior to welding andleft to shrink while cooling after welding. This technique provides the active andpassive lateral pressure to overcome the lateral expansion of the concrete undercompression. The uses of this technique are reported extensively for retrofittingof damaged columns in the past earthquakes (Wu et. al. 2006, Murty et. al. 2005).
The main disadvantage of steel jacketing are a) it is labour intensive b) very time
consuming c) involves lot of investment and skill and, d) it cannot be used inthose places which are prone to electric and magnetic radiations.
2.3 FRP Jacketing
Recently advanced composite materials made up of fiber-reinforced jackets
formed by bonding the continuous carbon, glass, or other synthetic fibers, fiber
sheets to wrap the concrete surface along with matrix materials such as epoxy,vinyl ester resins etc. The primary function of transversely continuous jackets is toprovide passive confinement to concrete similar to steel. Based on comprehensive
experimental studies, advanced composite material jackets have proven to beeffective measure to repair and retrofit squat circular and rectangular columns
with insufficient shear reinforcement (Haroun et al, 2003). Fiber reinforced
composite jackets have shown superiority over steel jackets since they do not alterweight of the columns significantly.

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3. EXPERIMENTAL DETAILS
3.1 Description of test RC Frame
The RC frame used in current study is a partially damaged 1:2.5 scale model of a
prototype RC building (figure 1) which was tested for seismic performance using
various strengthening schemes such as use of steel braces, strengthening ofcolumns by means of external steel cage and energy dissipation device (aluminum
shear yielding device) in an earlier study (Sahoo and Rai, 2008).
160

160

(

Slab 800X500

)

50

180

(

Beam 160X180

)

2130

(

Footing 250 X 300
300

)

2280

300

3200

Figure 1: Dimensions of test frame
Properties of the frame under study
Excited mass (consisting of self weight of beam, slab and 1/3rd of mass ofcolumns + imposed load) = 1905 Kg.
Dimensions of the column = 160mmX160mm
Longitudinal reinforcement = 4 numbers of 16mm diameter Fe-415 bars
Unconfined compressive strength of concrete = 35 MPa
Initial lateral stiffness = 7.8 KN/mm
Lateral Stiffness after partial damage =2.1 kN/mm
Final stiffness of the frame as reported = 1.00 KN/mm (after damage)(Sahoo and Rai, 2008)

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3.3 Strengthening Scheme
The RC frame used in the study was damaged considerably. It was repaired andretrofitted in three stages using epoxy, epoxy mortar and finally by means of FRP
jacketing.
3.3.1 Use of Epoxy and Epoxy Mortar
Fine cracks in beams and columns were filled by low-viscosity epoxy SIKADUR52 using injecting needle (figure 3) and allowed to cure for at least one day. The
epoxy had a mix density of 1.14 kg/L and consisted of two parts A and B mixed in
the ratio 8:1. Its viscosity at 30º is 250 CP. Its tensile strength is 34 MPa andcompressive strength greater than 60 MPa after 14 days.

Figure 3: Epoxy Injection and repair using epoxy mortar
Major cracked and damaged concrete cover was removed first and then portions
were repaired using epoxy mortar SIKADUR-31 and the damaged frame wasbrought back to its original dimensions. The epoxy mortar is a solvent free,
thixotropic mortar based on the combination of epoxy resins and speciallyselected high strength fillers. It consists two parts A and B mixed in the ratio 2:1.
The density of the mix is 1.85 kg/Ltr and compressive strength at 14 days equals
to 60 MPa. A small form work was constructed so as to maintain the original
dimensions of repaired columns.
3.3.3 Retrofitting using fiber-reinforced polymers
The main objective of retrofitting consists of strengthening the columns byconfining the unconfined concrete by means of fiber reinforced composite
jacketing. The standard provisions given in ACI 440-2R was used to calculate thenumber of layers of GFRP fabric required to bring back the confined compressive
strength of cracked/damaged concrete equivalent to that of the unconfinedcompressive strength of initial concrete used in the construction original RC
Frame.
The axial compressive strength of a normal weight concrete member confinedwith an FRP jacket can be calculated using formula (ACI 318-05)
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VietnamΦPn = 0.85 Φ [0.85 fc (Ag-Ast) +fy ×Ast]
where,
fc,as-built = unconfined compressive strength of cracked concrete
fc,target = target unconfined compressive strength of concrete
fcc= target confined compressive strength of concretefl= Maximum confining pressure due to FRP JacketAg= gross area of concreteAst= area of longitudinal reinforcementfy= yield strength of main reinforcementΦ= constant =0.65
fc,as-built = 20 MPa
fc,target = 35 MPafcc= 38.15 MPafl= 14.63 MPa= constant =0.95
ΨfNumber of Plies = [fl × (b2 + h2)2] / [Ψf×2×Ef×tf×€f]
Property of GFRP used in the experimental program:
Bidirectional woven FabricArea density = 360 g/m2
Volume fraction = 40%
Thickness per layer, tf = 0.75mm
Ultimate tensile strength = 220 MPa
Modulus of elasticity, Ef = 19 GPa
Rupture strain, €f = 0.015
Number of layers of GFRP required = 8
The eight layers of GFRP were applied after initial repair of the damage columns
by means of epoxy and epoxy mortar and allowing sufficient time for curing. First,
a layer of SIKADUR 52 Epoxy was applied over the surface which was alreadycleaned off any loose mortar or dust remaining over it. Then the first layer of
GFRP fabric was applied over it and another layer of epoxy was applied so as tocomplete impregnate the fibers completely. This layer was allowed to cure for aday, and following day remaining seven layers of GFRP sheets were applied
providing sufficient time for curing.
Two layers of GFRP fabric were applied to the tension face of the beam because
minor cracks were observed in the tension face of the beam.
3.4. Instrumentation and Test Set-up
The objective of this experimental investigation is to evaluate the linear elastic
behavior of frames using the vibration and slow-cyclic tests. Thus, a test set-up(figure 4) was prepared which consisted of loading devices, reaction frame, andinstrumentation consisting of various sensors and data acquisition system (Sahoo,
and Rai 2008) to record load deformation data. Following are the details of theexperimental test setup:

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LVDT’’s

Actuator
L1

190

L2

570

L3
570

L4

260

L5

150

Figure 4: Schematics showing instrumentation and test setup
4. TEST RESULTS AND DISCUSSIONS
4.1 Force vibration test (Partially Damaged Frame)
The main objective of force vibration test was to determine the damp natural
frequency of the frame. Natural frequency is considered as the frequency at which
the maximum response of the frame is observed. The partially damaged test frame
was subjected to the harmonic vibrations of varying frequencies by the electrodynamic shaker placed at the center of the slab. The observed natural frequency
was 2.75 Hz (equivalent to initial stiffness of 0.6 kN/mm) as shown in figure 5.
1.2

Velocity FFT Amplitude,Normalised

1

0.8

0.6

0.4

0.2

0
0

2

4

6

8

10

12

14

16

Frequency (Hz)Figure 5: Frequency response of the partially damaged test frame

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4.2 Evaluation of Frame Retrofitted with GFRP
4.2.1 Forced Vibration Test
After initial damage repair, the test frame was retrofitted using 8 layers of GFRP
fabric as per calculations done using ACI 440-2R and allowed to cure for twenty
four hours. First, a layer of SIKADUR 52 Epoxy was applied over the surface
which was already cleaned off any loose mortar or dust remaining over it. Thenthe first layer of GFRP fabric was applied over it and another layer of epoxy wasapplied so as to complete impregnate the fibers completely. This layer wasallowed to cure for a day, and following day remaining seven layers of GFRP
sheets were applied providing sufficient time for curing. After curing the frame
was tested under forced vibration test (figure 6) which yielded a significant
improvement in stiffness. The natural frequency observed was 7.0 Hz and thestiffness calculated was 3.84 kN/mm.
4.2.2 Load-controlled slow-cyclic test
Load-controlled slow-cyclic test was carried out to determine the initial stiffnessof the frame. The frame was subjected to a cyclic lateral load of 5kN in addition to
constant gravity load of 18.7kN uniformly distributed over the slab. Figure 7
shows the lateral load-roof displacement response of the RC frame under cyclicloading. The peak displacement at roof of the frame was measured in push andpull direction of lateral loading of magnitude ±5kN. Initial lateral stiffness of theRC frame which was computed as the ratio of peak lateral load to lateraldisplacement was computed as 3.43 kN/mm, showing an increase of over 500% ascompared to original damaged frame.
1.2

Velocity FFT Amplitude,Normalised

1

0.8

0.6

0.4

0.2

0
0

2

4

6

8

10

12

14

16

18

20

Frequency (Hz)Figure 6: Frequency response of retrofitted Frame320

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8

6

4

Load (kN)

2

0
-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

-2

-4

-6

-8

Displacement (mm)Figure 7: Load Displacement response of retrofitted Frame
4.3 Displacement controlled slow cyclic test
The strengthened RC frame was also subjected to displacement controlled slow
cyclic test as per ACI recommendations [ACI 374.1-05] starting at different storey
drift levels. The displacement history consisted of gradually increased storey
drifts of 0.20%, 0.35%, 0.50%, 0.75%, 1.00%, 1.40%, 1.75%, 2.20%, 2.75%,
3.50% and 4.50%.Cyclic lateral load was applied to the RC beam of the frame in
the form of a series of ramps at varied rate of loading such that the time required
to complete the three cycles of each drift level was about five minutes.
Initially the fame was subjected to a storey drift of 0.20% and the response of theframe was recorded using LVDT’s. During the loading cycle for storey drift of
0.35% first cracking sound was observed, probably due to debonding of the layerof GFRP, however no major crack was observed in the column even at storey driftof 2.2%.Very gradual decrease in the value of stiffness was observed up to thestorey drift of 2.2%, after which there was somewhat large decrease in the
stiffness. At the storey drift level beyond 2.75%, continuous cracking sound washeard due to debonding of GFRP. Cracks also began to appear near ends of thecolumn due to formation of plastic hinges.
The extent of damage in various storey drift is shown in Table 1, along with thetest data of earlier study on the same frame (Sahoo & Rai,2008).
By comparing the values obtained from displacement controlled slow cyclic testwith that of the earlier study [Sahoo and Rai,2008], a significant improvement inlateral load carrying capacity as well as lateral stiffness at various drift level
varying from 0.20% to 4.5% has been observed . The hysteretic loops formed arealso very stable without any sudden drop in stiffness of the frame up to 2.2% drift
storey level.

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Storeydrift(%)

Lateral
disp.
(mm)

0.20

2.92

TABLE 1: Test results
Lateral Load, kN
Lateral stiffness,(Sahoo & Rai,2008)
kN/mm[% increase](Sahoo &Rai,2008)[% increase]9.49(5.29)[79.4]
3.25(1.81)[79.55]

0.25

3.72

11.83(6.56)[80.33]

3.18(1.76)[80.68]

0.35

5.12

16.18(8.66)[86.88]

3.16(1.69)[86.98]

0.50
0.75
1.00

7.43
11.01
14.71

22.14(11.77)[88.10]
31.82(17.05)[86.62]
38.83(22.69)[71.13]

2.98(1.58)[88.60]
2.89(1.54)[87.66]
2.64(1.54)[71.42]

1.40

20.67

52.50(31.62)[66.03]

2.54(1.53)[66.01]

1.75

25.77

63.14(39.39)[51.00]

2.45(1.53)[60.13]

Cracks injointsDebonding

2.20
2.75

32.38
40.59

75.45(49.97)[50.99]
86.88(61.43)[41.42]

2.33(1.54)[51.03]
2.14(1.51)[41.72]

Debonding
Debonding

3.5

51.62

88.27(69.20)[24.66]

1.71(1.34)[27.61]

4.5

66.35

89.2071.26[25.17]

1.34(1.07)[25.23]

ObservationsFirst cracking
sound

Crack
widening
Plastic hinges
in column

5. CONCLUDING REMARKSThe performance of the partially damaged moment resisting frame was evaluatedafter GFRP retrofitting scheme by means of forced vibration test, load controlled
slow cyclic test and finally by displacement controlled monotonic cyclic loading
test. The results of the tests clearly shows that there was a significant
improvement in the stiffness of the damaged frame from 0.6 kN/mm to 3.84
kN/mm, an increase of over 600%. There was also substantial improvement in thelateral strength of the frame. The displacement controlled slow cyclic tests also
show that the RC frame retrofitted with GFRP fabric performed very well. No
sudden drop in stiffness or load was observed in the specimen up to a storey driftof 2.2% which shows its excellent behavior considering the fact that the allowable
storey drift of the moment resisting frames is considered as 1.5% for buildings ofless than four storey and 2.0% for buildings of more than four storeys (IBC, 2000).
The load –displacement curve (figure 8) shows that that the hysteresis loops arestable without much pinching which is an indication of good retrofitting technique.

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100
80

Lateral Load (kN)

60

-80

40
20
0
-60

-40

-20

0

20

40

60

80

-20
-40
-60
-80
-100
Displacement (mm)Figure 8: Load –displacement at various drift levels
REFERENCES
Bai,Jong-Wha and Hueste, M .B .(2003) “seismic Rehabilitation for Reinforced
Concrete Building structures”. Consequence-Based Engineering Institute, Final
Report, Texas A&M university.
CEN.(2005).”Design of structures for earthquake Resistant Part 3: Assessment
and retrofitting of buildings.” Eurocode-8.
Wu,Y., Liu,T. and Oehlers,D.J.(2006) “Fundamental principles that govern
Retrofitting of Reinforced Concrete Columns by Steel FRP Jacketing.” Advancesin Structural Engineering, Vol 9, No. 4, PP 507-533.
Murty C.V.R., Greene M., Jain S.K., Prasad N.P., and Mehta V.V. (2005) “A
Recovery Reconnaissance Report” Earthquake Engineering Research Institute,
Oakland, CA
Haroun.M A.Mosallam,A. S., Feng, M. Q. and Elsandedy,H.M (2003).
“Experimental investigation of seismic repair and retrofit of bridge columns bycomposite jackets”. Journal of reinforced plastics and composites, Volume 22,
No 14.pp 1243-1268.
Sahoo, Dipti R. and Rai, Durgesh C.(2008), “Siesmic Strengtheningof OpenGround-Storey RC Frame Using Steel –Caging And Aluminium Shear-Yielding
Dampers”. IIT Kanpur.

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324

New Technologies for Urban Safety of Mega Cities in Asia

Savar building tragedy in Bangladesh:Way forward
Mehedi Ahmed ANSARY
Professor, Department of Civil Engineering,
BUET, Dhaka, Bangladesh
ansary@ce.buet.ac.bd
Naima RAHMAN
Research Planner, BNUS, Dhaka, Bangladesh
naima.rahman05@gmail.com

ABSTRACTAs garments industries have become the main source of foreign income of
Bangladesh, many new factories have been established in Dhaka City. But due tolack of concern from authorities, this industry has become one of the highly risk
working sector for workers. Garment industry has been experienced many fire
accidents in the last decades taking life of many workers. But the recent accidentof building collapse in Savar is the worst of all. This incident took lives of 1132
people and left many disabled. About 332 people are still missing according totheir families. Six garments factories, one bank and many shops are going into
debris within a few minutes without any shake from outside. In this study, theauthors discuss the reason behind the accident, the role of authorities in searchand rescue, overall co-ordination, rehabilitation and legal activities. The authors
also recommend some measures to avoid this type of disaster in Bangladesh.
1. INTRODUCTION
1.1 BackgroundOn 24 April at 9am, a nine-storey building collapsed in Savar, 25
kilometers north of the Bangladesh capital, Dhaka (see Figure 1). As of August,1132 people died (CPD, 2013), 2438 people were rescued and were provided withimmediate basic first aid or transferred to nearby hospitals for medical attention.
The building housed several garment factories, a bank and several shops. The
factories manufactured apparel for brands including Benetton, Bonmarché, CatoFashions, the Children's Place, El Corte Ingles, Joe Fresh, Mango, Matalan,Primark and Wal-Mart. According to BGMEA (Bangladesh Garments
Manufacturers and Exporters Association) 2800 workers of the 6 garment
factories were in the building during the accident. But the actual number is around3900 (CPD, 2013). Day before the incident, some cracks developed on somepillars and a few floors of the building following a jolt, causing panic among thepeople working there. They rushed out of the building and some even got injuredin the process, said a number of garment workers and locals. The industrial police

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Vietnamvisited the building that day and asked the building authorities not to open thebuilding. But the warnings and instructions were ignored. The shops and the bankon the lower floors immediately closed after cracks were discovered in thebuilding. But workers of at least two garment factories at Rana Plaza were forced
to join their workplaces following a false assurance on the building’s safety froma local engineer, relatives of the victims alleged. As a result the deadliest garmentfactory accident in the history of Bangladesh occurred which is also considered as
the deadliest accidental structural failure in the modern world.

Figure 1. Location of the collapsed building
1.2 Purpose of the Study
The purpose of the study is to focus on overall scenario of the Savar tragedy.
This article presents the search and rescue effort undertaken by different agencies
in Bangladesh to rescue people from underneath the collapsed building and tries
to explain the reasons behind the building collapse. Figure 2 shows the collapsedbuilding.

Figure 2. The collapsed building

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2. REASONS BEHIND THE BUILDING COLLAPSE
Rana Plaza was a 9-storied industrial building with a single basement. The local
municipality gave the owner permission to construct a 5 storey commercial
building with one basement in 2005 and later allowed the owner to extend it up to
9-storey, without considering the consequence of such action. The width of thebuilding was around 25 m and length around 80 m. A typical grid of the buildingis 5.2 m by 8.2 m. The column sizes vary from 35 cm by 35 cm to 45 cm by 45
cm. The building was supported by pile foundation having 450 mm diameter andlength of 18.3 m. Three main reasons can be attributed to the collapse of thestructure: (i) Addition of four extra floors; (ii) Conversion of the building fromcommercial to industrial use and (iii) Placement of Power Generators at the higher
floors. The steel grade used was 60 grade deformed bar and concrete strength was
found around 3000 psi [see Figure 3].

Figure 3. (a) Broken samples collected from the building site and (b)Concrete cores collected from beams, columns and slabs of the collapsedbuilding
2. SEARCH AND RESCUE OPERATIONS
2.1 Search and Rescue
Local Volunteers, volunteers of Bangladesh Red Crescent Society,personnel from Bangladesh Fire Service and Civil Defense, Bangladesh Armed
Forces personnel, Border Guard Bangladesh and local police were involved insearch, rescue and evacuation operation of trapped garment workers at Savar
Building collapse site. On the day of incident, these organizations rescued 1762
people alive.

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October
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The local people started rescue operation immediately after the incident. Then
Bangladesh Army, Navy, Fire Service, BGB, Police and different volunteer teams
joined in the rescue activities. Police and RAB are engaged to maintain law andorder situation at the site. Rescue operation is continuing.1200 volunteer from
Dhaka, Keraniganj and Narayanganj area (trained by Comprehensive disastermanagement Programme (CDMP) under Ministry of Disaster Management andRelief) are working in Rescue operation. To purchase rescue equipment instantly,
MoDMR has given BDT 5,00,000 to Fire Service and Civil Defense. Figure 4 and5 shows the acticity of people during Search and rescue operation

Figure 5. Search and rescue operation
More than 200 volunteers under the Department of Fire Service and Civil Defense(FSCD) who have received training under the previous DIPECHO VI Project
implemented under the NARRI Consortium were immediately deployed after theincident and are working on location.
2.2 Overall Coordination
Armed Forces Division (AFD) of Bangladesh coordinated the search andrescue operation. Eman medical hospital played an important role for the injured
victims by providing medical support. Fifteen Medical teams from Bangladesh
Army, two from Navy, one from Air Force, one from BGB and ten teams fromhealth department, the doctors and medical workers of local hospital and clinic areengaged for treatment of injured people.

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2.3 Contribution of local volunteer
Some local people involved in search and rescue operation among themsome died unexpectedly. Figure 6 shows the number of death and rescued alivefrom the day of accident to the day of last dead body found.

Figure 6. Number of death and rescued alive
From the day of accident, 574 people were rescued alive whereas 124 people were
found dead. On the second day the highest number of people (1762) was saved
alive. Alive people were found up to 4 days of the accident. But a woman named
Reshma was found and rescued alive and almost unhurt under the rubble 17 days
after the accident on 10 May. Dead bodies were found almost every day from 24
April to 12 May.
The Bangladesh Red Crescent Society was among the first responders on thescene. 100 trained volunteers are on the ground on a rotation providing search andrescue, basic first aid and safe drinking water. The organization also established amobile medical team assisting the wounded. The Red Crescent Society ambulanceservice transported wounded people to various hospitals, and the organization also
helped with the management of dead bodies. Restoration of Family Link (RFL)
volunteers provided mobile phone services for the injured (see Figure 8) toconnect with their families and relatives, and also compiled a list of the missing,injured and dead.

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October
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Armed Forces Division (AFD) of Bangladesh engaged in the disaster managementof the accident most as their name came in newspaper articles for 37 times. They
appeared every day in newspaper from the day of accident to 14 May. Then comeBangladesh Fire Service and Civil Defence (BFSCD) with 20 times. Local
volunteers contributed significantly with 15 times appearance in newspaper. The
Department of Disaster Management (DDM) which is responsible for disastermanagement in the whole country appeared only 3 times in newspaper articles.
The figure 7 shows the number of key words in newspaper articles from 24 April
to14 May.

Figure 8. Some of the critically injured garments workers
3. MENTAL TRAUMA AND REHABILITATION
After the Savar tragedy, many victims and volunteers have been suffering from mental
trauma of accident. One volunteer named Rubel committed suicide from the shock. Manyof those who survived have lost their limbs, many have become paralyzed. Ironically, allthose people are in their productive age and most of them are the only earning member of
their family. With disability and deformity, it has become extremely difficult for them to get

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back to work again. But with long term rehabilitation support, they can lead a better life
with acquiring productivity and mobility. After such traumatic experiences, nearly
everyone will have the symptoms of stress and grief for the first month which is a natural
grieving process. Some will still experience those symptoms and they cannot come to termswith what has happened and suffer Post Traumatic Stress Disorder (PTSD). Mental trauma
can be solved by rehabilitation for a long time
4. NATIONAL VS. INTERNATIONAL RESPONSE
The Savar tragedy took limelight of both national and international media after the day ofincident. Many international leaders including Pope, Secretary General of United Nations,
ILO and international NGOs showed their deepest concern for the victims. The European
Union (EU) has raised strong concern over labor conditions and declared appropriate action
to encourage improvements in working conditions in Bangladeshi factories. Major western
clothing retailers are squeezing Asian suppliers and a flawed approach to ensuring evenbasic working standards are fuelling conditions for tragedies like the Savar disaster.
United States of America suspended the Generalized System of Preferences (GSP) facilities
on the entrance of Bangladeshi product into the US market after Savar tragedy considering
the accident of Savar Rana Plaza, Tazrin Fashion, and unsolved case of murder of a tradeunion leader. They have also concerned about the safety, development of the standards ofthe laborers in Bangladesh as the biggest labor union of the USA, AFL-CIO has been
convincing the government of USA to stop the GSP facilities for Bangladesh since 2007.
World Health Organization is going to provide more emergency drugs as per government
request and has already provided blood transfusions sets, dressing and first aid materials
along with emergency medicines to Savar Upazila Health Complex and Enam Medical
College Hospital for the injured persons.
Islamic Relief, Bangladesh provided various equipments to support search and rescue toFire Service and Civil Defense (FSCD). Action Aid, Bangladesh has provided emergency
rescue equipment worth BDT 2,00,000 for FSCD’s rescue team and food worth BDT
50,000,00 for Urban Community Volunteers. Emergency medicine of BDT 10,000.00 isalso supplied for injured people.
BDT 20000.00 has been provided to each deceased family. Total BDT 86,60,000 has been
distributed to 433 families. Each injured person will get BDT 5000. BDT 47,15,000 has
been distributed among 943 injured. BDT 4,00,00,000 has been allocated from MoDMR to
DDM. DDM has allotted BDT 3,00,00,000 to District Administration for distribution.
The following graph shows the number of national and international articles on Savar
tragedy in the Daily Star Bangladesh.

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October
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collapse
After the disaster, government of Bangladesh promised to give about $1,250 incash and $19,000 in savings certificates to the families or relatives of diedworkers, but yet has provided about $1,250 to $5,000 to some 777 families.
Nearly 300 bodies were not identified and claimed by families or relatives.
5. RECOMMENDATION
Bangladesh faced its worst human tragedy through Rana Plaza building collapse
at Savar, Dhaka. In 1996 at Kalabagan, in 1997 at Khilgaon, in 2004 at
Sakaribazar, in 2005 in Savar, in 2006 at Mahakhali, in 2010 at Hatirjheel and at
Kathalbagan similar incidence occurred where altogether several hundred people
were killed. Enforcement of Bangladesh National Building Code (BNBC) has
become the top priority.
Immediately, we need to set up a Building Regulatory Authority (BRA) as
prescribed in BNBC. BRA will aim to deliver: Better safeguards for consumers;
Building industry transformation and Legislative reform. The Building Authority
will work closely with four statutory bodies to provide industry leadership andwill regulate building quality. The associated bodies will be the Building
Advisory Council, Building Appeals Board, Building Practitioners Board and the
Building Regulations Advisory Committee. The Authority and four bodies will332

Regulate Bangladesh’s building industryAdminister the registration of a country’s building practitioners andmonitor their conductAdvise the relevant Minister and the Government on building regulatory
development

Administer building legislation, the Building Act 1952 and Building
Regulations 2008

Resolve disputes and appeals arising from the Building Act

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Inform consumers about building and renovatingCommunicate changes that occur in building legislation

Promote improved building standards nationally and internationallyProvide comprehensive information on building activity

Inform industry decision making through data and analysis

Facilitate industry researchSupport the uptake of information technology and e-commerceEncourage sustainable and accessible building design, construction anduse

The BRA will carry out these functions in consultation with a wide variety of
stakeholders.

6. CONCLUSIONS
Many questions have already been raised about the future of the garments industry
in Bangladesh after a number of accidents like Spectrum Garment Accident,
Tazreen Fashion Disaster and the latest Savar Building Collapse. A large numberof foreign buyers including Disney have decided not to buy clothes from
Bangladesh because of the poor working condition in the garments industry. It
may severely damage the social and economic future of Bangladesh in long term.
The government, the leaders of the garments industry, the NGOs, and the civilsociety have to come forward in unity to increase the quality of working
conditions and livelihood of the workers of this sector. The foreign buyers needassurance from the government that they will never again face this kind of disasterin Bangladesh.

REFERENCES

BNUS field survey, 2013.
Centre for Policy Dialogue (CPD), “Independent Monitoring Report”,
August, 2013.
The Daily Star. Accessed from 24 April to 25 May 2013.

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Secular changes in people’s consciousness
regarding earthquake early warning-Based on national survey(2009-2012) in Japan-

Miho OHARA1 and Atsushi TANAKA2
1
Associate Professor, International Center for Urban Safety Engineering (ICUS),
Institute of Industrial Science/ Interfaculty Initiative in Information Studies,
The University of Tokyo, Japanohara@iis.u-tokyo.ac.jp
2
Professor, Center for Integrated Disaster Information Research,
Initiative in Information Studies
the University of Tokyo, Japan
ABSTRACTIn Japan, earthquake early warnings (EEWs) have been broadcast to the generalpublic since October 1, 2007. Issuance times of EEW increased drastically after
the Great East Japan Earthquake, and citizens had much more frequent
experience with EEWs. However, frequent missing and overlook of EEWs also
occurred after the Great Japan East Earthquake, possibly adversely affecting thetrustworthiness of EEWs.
This study analyzes secular changes in rates of recognition and reception
experiences of EEW based on the regular disaster information survey from fiscal
2009 to 2012. It also analyzes awareness regarding EEW accuracy by comparing
study results with EEW issuance history nationwide. Secular changes in the
expectations of the general public regarding EEWs are also clarified.
As a result, the rates of recognition and reception experience of EEWs increased
significantly after the Great East Japan Earthquake. It was confirmed that therates of recognition and reception experience tend to rapidly increase whenissuance times of EEWs increases. The both rates exceeded approximately 70%
when the average issuance times exceeded roughly 10. The rate of responding“warnings should positively be issued in spite of the possibility of missing
warnings” was as high as 85.6%. The decrease in the accuracy of EEWs did not
clearly affect intention to use of EEWs. Meanwhile, reception experience leaded
to positive intention to use.
As expectations for future EEW, needs for information about predicted intensity
and time until ground motion arrives are increasing. Needs for information about“what to do specifically after EEW“ are decreasing, suggesting a possibility of
insufficient understanding for proper behaviors. Interest in behaviors when
receiving EEWs should be enhanced especially in the regions where EEWs rarely
issued.
Keywords: Earthquake Early Warning, people’s consciousness, Great East Japan
Earthquake

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1. Introduction
Earthquake early warnings (EEWs), also known as alerts, have been issued to thegeneral public since October 1, 2007, especially in regions with predicted
intensity of 4 or more when predicted intensity of 5 lower or more is anticipated.
According to records from the Japan Meteorological Agency (JMA) website,
EEWs were issued 18 times before the March 11, 2011, Great East Japan
Earthquake and 114 times from that date until the end of December 2012.
Issuance times increased drastically after the March 2011 quake, and citizens hadmuch more frequent experience with EEWs. Frequent missing and overlook of
EEWs occurred after the Great Japan East Earthquake, possibly adversely
affecting the trustworthiness of EEWs.
The University of Tokyo’s Center for Integrated Disaster Information Research(CIDIR) has annually conducted “regular survey on the degree of disaster
information recognition and trends in disaster awareness” (hereafter, regulardisaster information survey) since fiscal 2009. This paper analyzes secularchanges in rates of recognition and reception experience related to EEWs bycomparing results of 2012 with those since 2009. Issuance times and hit, missing,overlook rates of EEWs nationwide thus far are also calculated and calculation
results are compared with those of regular disaster information survey to analyze
regional differences among awareness of the general public concerning EEW
accuracy. Expectations of EEWs are also analyzed.
EEWs include two types of warning; the one is the alerts for the general public
receiving by TV or radio etc., the other is the alerts for advanced users receivingby special receiving devices. EEWs for advanced users are issued, as a rule, when“the amplitude of the P wave or S wave is 100 gal or more” and “the calculated
magnitude is 3.5 or more or the maximum predicted intensity is 3 or more”. The
EEW in this paper means the former one, the alerts for the general public.
2. Analysis of Rates of Recognition and Reception Experience with EEWs
2.1 Issuance Times of EEWs Nationwide
The JMA website gives detailed data on the EEWs issued, such as issuance date,location, and estimated magnitude. Based on this, Figure 1 shows EEW issuancetimes by month from October 2007 to December 2012. The highest numbers were
46 in March 2011, when the Great East Japan Earthquake occurred, and 26 inApril 2011. Since then, issuance times have increased drastically due toaftershocks and induced earthquakes, although they decreased to 1–3 times amonth after October 2011 and remained at that level thereafter. All issuances inMarch 2011 were after the great earthquake. EEWs are issued to approximately
200 prediction regions nationwide. Miyagi Prefecture, for example, is divided into
north, central, and south regions. Average issuance by prefecture was calculated
based on issuance for individual prediction regions as shown in Fig.2. The highest
after the Great East Japan Earthquake was 56 times for Ibaraki Prefecture, 51 for
Fukushima Prefecture, 33 for Tochigi Prefecture, 31 for Chiba Prefecture, and 28
for Miyagi Prefecture. Fukushima and Ibaraki Prefectures thus received morewarnings than Iwate or Miyagi Prefectures where the damage from the336

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concomitant tsunami was significant. For comparison, no warnings were issued
until December 2012 to the prefectures of Kyoto, Osaka, Hyogo, Nara, Tottori
Okayama, Yamaguchi, Tokushima, Kagawa, Ehime, Kochi, Fukuoka, Saga,
Nagasaki, Kumamoto, Oita or Miyazaki Prefectures. No regions in the Shikoku
district received warnings, either. The first EEW was issued on April 13, 2013, tothe 10 prefectures of Kyoto, Osaka, Hyogo, Nara, Kagawa, Tokushima, Ehime,
Kochi, Tottori, and Okayama when an earthquake hit Awaji Island in Hyogo
Prefecture (Please note, that the scope of this paper does not include this in Fig. 2).

200804
200805
200807
200807
200809200811
200908200910201002
201003
201009201010201012
201103
201104
201105
201106
201107
201108201109201110201111
201112
201201
201202
201203
201204
201205
201206201207
201208201209201210201211
201212（times）
50
46
45
40
35
30
26
25
20
15
10
5 5 5
4
3 3 2
3
3 4
2 1 1 2 1 1 1 1 1 1
5 1 1
1 2 1 210 1 0 0 0 1
0Figure 1: Issuances of EEWs from 2007 to 2012
（times）

56

60
50

From Mar 11, 2011, to Dec 31, 2012

40
30
20
10

33

31

28
21

20

22

25

23

20

13
10
7 6
7 6
5
5
5
4 6
4
4 2
4 2 2 2 33
11 1
1
0 0 01 1 1 0 1 01 00 01 00 00 00 00 01 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 10 10
13

Hokkaido
Aomori
Iwate
Miyagi
Akita
Yamagata
Fukushima
Ibraki
Tochigi
Gunma
Saitama
Chiba
Tokyo
Kanagawa
NiigataToyamaIshikawa
Fukui
Yamanashi
NaganoGifu
Shizuoka
Aichi
Mie
Shiga
Kyoto
Osaka
Hyogo
Nara
Wakayama
Tottori
Shimane
Okayama
Hiroshima
Yamaguchi
Tokushima
KagawaEhime
Kochi
Fukuoka
Saga
Nagasaki
Kumamoto
Oita
MiyazakiKagoshima
Okinawa0

Before March 10, 2011

51

Figure 2: Average issuance of EEWs by prefecture
2.2 Overview of Regular Disaster Information Survey
The CIDIR, The University of Tokyo has annually conducted regular survey onrecognition degree of disaster information and disaster awareness since fiscal
2009. The surveys were performed as follows.
• Research region: Entire Japan• Research period: December of 2012, 2011, 2010, and 2009
• Research method: Internet questionnaire• Research target: Males and females aged 20 to 69. Two-thousand people for2009 and 2010 and 3000 people for 2011 and 2012. The sample number foreach prefecture was distributed proportionally to the population composition
ratios.

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2.3 Secular Changes in Rates of Recognition and Reception Experience with
EEWs
This section analyzes the secular changes in rates of recognition and reception
experience of EEWs by comparing the results of the regular disaster information
survey conducted in 2009-2012. The “recognition rate” is defined as a “rate ofpeople who have heard of information.” EEWs for the general public can bereceived by TV, radio, cell phones, and radio communications for disasterprevention and administration. Here, the “reception experience rate” is defined asa rate of people who have received EEWs by themselves by those means. The“recognition rate” is 56.1% in 2009 and 61.3% in 2010 before the March 2011
quake. The rate significantly increased to 79.3% as of December 2011 after theGreat East Japan Earthquake, approximately 1.29 times compared to the figure in
the previous fiscal year. This can be considered due to the effect of numerous
EEWs issued after the March 2011 quake.
Figure 3 shows the age-based secular changes in rates of recognition andreception experience of the EEW. Here, the reception experience rate is shown
only after 2010 because this item was not included in the survey in 2009. The
recognition rate in 2009 and 2010 are highest for those who are in their 20’s,
while it increased from December 2011 after the Great East Japan Earthquake forall generations.
The reception experience rate is 27% on average for all generations in 2010 and
54.9% in December 2011 after the March 2011 quake, increasing approximately
twofold. The reception experience rate decreased for all the generations in 2012. It
is worrying that the memory of receiving numerous EEWs will fade and theconsciousness about EEWs will diminish after the next fiscal year as time passes
from the Great East Japan Earthquake.
Figure 4 shows the district-based secular changes in rates of recognition andreception experience of the EEW. The recognition rate exceeded 50 % in all the
districts as of 2009. In 2009, the highest value of 61.9% is for Tohoku district,
whereas the lowest of 50.5% is for Kyushu Okinawa district. In 2011 after the
March 2011 quake, the highest value increased to 92.3% for Tohoku district andthe lowest to 67.3% for Kyushu Okinawa district.
The results of district-based reception experience rate show a larger regional
difference than those of recognition rate. The reception experience rate for
Tohoku district is the highest in every year, increasing approximately 1.88 times
from 47.3% in 2010 to 88.8% in 2011. The rate slightly decreased to 83.7% in
2012. In contrast, the rates for Hokkaido and Chubu district in 2012 are as low as
approximately 40% and those for western Japan, Kinki, Chugoku, Kyushu,
Okinawa districts are all approximately 20%. 13.0% for Shikoku district in 2012is the lowest.
2.4 Analysis of Relationship Between Issuance Times per Region and
Recognition Rate/ Reception Experience Rate of EEWs
Based on the results above, this section analyzes the relationship between average
issuance times per prefecture and recognition rate/ reception experience rate of
EEWs. Figure 6 plots the average issuance times of each prefecture from March

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(%)

（％）

90
80
70
60
50
40
30
20
10
0

70

20's
30's
40's
50's
60's

60

20's

50

30's

40

40's

30

50's

20

60's

10
0

2009

2010

2011

2012

2010

2011

2012

(a)
Recognition rate(b) Reception experience rate
Figure 3: Age-based secular change in rates of recognition and reception
experience of EEWs
（%）

（%）

100

100

Hokkaido
Tohoku

80

Kanto
60

Chubu

60

40

Kinki

40

Chugoku

20

Kyusyu, Okinawa
2009

2010

2011

Tohoku
Kanto
Chubu
Kinki
Chugoku

20

Shikoku0

Hokkaido

80

Shikoku
Kyusyu, Okinawa

0

2012

2010

2011

2012

100
90
80
70
60
50
40
30
20
10
0

Reception experience rate
as of 2012

Recognition rate as of 2012(a) Recognition rate(b) Reception experience rate
Figure 4: District-based secular change in rates of recognition and reception
experience of EEWs

0

20

40

60

Issuance times after March 11, 2011

100
80
60
40
20
0
0

20

40

60

Issuance times after March 11, 2011(a) Recognition rate(b) Reception experience rate
Figure 5: Relationship between issuance times and rate of recognition or reception
experience of EEWs
11, 2011 to the end of December, 2012 (Fig. 2) against the recognition rate andthe reception experience rate as of 2012. Each plot in the figure indicates
individual values for each prefecture. When the average issuance times exceed 20,
the recognition rate is approximately 80-90% and the reception experience rate isapproximately 70% or more. In addition, when the average issuance times exceed
10, the rates of recognition and reception experience exceed approximately 70%.
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It is confirmed that the rates of recognition and reception experienceexponentially increase when the issuance times increase to a certain level.
However, the rates of recognition and reception experience are not the highest for
Ibaraki and Fukushima Prefectures, for which average issuance times are as
considerably high as more than 50. The rates of recognition and reception
experience per region are likely to differ depending on issuance time of a day,daytime or night. In the prefectures with the average issuance times of 0 or 1, therecognition rate ranges widely from 50 to 100%, while the reception recognition
rate 10 to 60%. The recognition rate exceeds 50% for prefectures that have notreceived the warning. The issuance times are 0 and the reception experience rates
are as low as slightly over 10% in Tokushima, Kochi, Ehime Prefectures in
Shikoku district, and Fukuoka, Saga, Nagasaki, Oita, Kumamoto Prefectures in
Kyushu district. Meanwhile, in Chugoku and Kinki districts, the issuance times
are 0 or 1, but the reception experience rate dispersed from about 20% to 60%. If
some TV program is being broadcasted nationwide when an EEW is issued, its
warning message can be seen in regions that are not the target. This is thought toincrease the reception experience rate for Kinki and Chugoku districts to which
warnings were quite rarely issued.
3. Analysis of Awareness of General Public Concerning Accuracy of EEWs
Next, the awareness of the general public concerning the accuracy of EEWs is
analyzed. The accuracy of EEWs for aftershocks and induced earthquakes after
March 11, 2011 decreased due to the facts such that concurrent multiple
earthquakes cannot be separated and the number of available seismometers
decreased because of blackouts and disruption of communication lines. According
to the press release of the JMA (2011), 70 warnings issued from 11 March to 28
April included many missing cases. At 17 earthquakes (24%), an EEW was issued
to the regions whose observed seismic intensity was 2 or less by mistakes.
In addition, among 46 earthquakes with the observed maximum intensity of 5
lower or more, 20 cases (43%) were overlooked with no warnings although EEWs
were issued to 26 cases (57%). They say these issues were partly resolved by the
upgrade of software as of August 10, 2011. However, missing and overlook of
EEWs may have affected motivation for use and recognition of usefulness
regarding the warning.
3.1 Regional Trends in Accuracy Based on EEW Issuance History
This section discusses the regional trends in accuracy based on issuance history
thus far. Here, trustworthiness of information offered by the JMA is focused on.
The regional trends in accuracy of EEWs is analyzed by comparing EEWs issued
to all or part of each prefecture with actually observed intensity, which is obtainedin the intensity database of the JMA website. EEWs is issued to regions withpredicted intensity of 4 or more when predicted intensity of 5 lower or more is
anticipated in some regions. Ohara analyzed issuance history until the end of
March, 2012 using a similar method. This paper includes comparison using thelatest data, expanding the target period to the end of December, 2012.

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Figure 6 aggregates hit, missing, overlook times of EEWs per prefecture before
and after the great earthquake. It excludes prefectures to which EEWs was issued
only once before and after the great earthquake. EEWs is issued to regions withpredicted intensity of 4 or more when predicted intensity of 5 lower or more is
anticipated in some regions. “Hit” warnings are therefore defined as those issued
to all or part of a prefecture concerning an earthquake with observed intensity of 4
or more in the same prefecture when intensity of 5 lower or more is observed inany region in the country. “Missing A” warnings are defined as those issued to allor part of a prefecture when no earthquakes occur in the country. “Missing B” isthe case in which a warning is issued to all or part of a prefecture when intensityof 4 or more is not measured in the same prefecture, but measured in otherprefecture. The case of missing A is inferior to the case of missing B. “Overlook”
warnings for a prefecture means the case in which EEWs is not issued when an
earthquake with intensity of 5 lower or more is measured in any region in the
country and intensity of 4 or more is also measured in the same prefecture.

青森
Aomori
岩手
Iwate
宮城
Miyagi

空振りＢ率（震災前）
Rate before March, 2011

Rate after March, 2011
空振りＢ率（震災後）

東京（伊豆諸島）Tokyo(Izuislands)
千葉
Chiba
神奈川
Kanagawa
Nagano長野
Niigata
新潟（佐渡以外）
Shizuoka静岡(d) Rate of Missing B
100％
90
80
70
60
50
40
30
20
10
0

東京（伊豆諸島）Tokyo(Izuislands)
千葉
Chiba
神奈川
Kanagawa
Nagano長野
Niigata
新潟（佐渡以外）
Shizuoka静岡

山形
Yamagata
秋田
Akita
福島
Fukushima
茨城IbarakiTochigi
栃木
Gunma
群馬
Saitama埼玉Tokyo
東京（23区・多摩）

青森
Aomori
岩手
Iwate
宮城
Miyagi

北海道
Hokkaido

空振りＡ率（震災前）
Rate before March, 2011
空振りＡ率（震災後）Rate after March, 2011山形
Yamagata
秋田
Akita
福島
Fukushima
茨城Ibaraki
栃木
Tochigi
Gunma
群馬
Saitama埼玉Tokyo
東京（23区・多摩）

見逃し率（震災前）
Rate before March, 2011
見逃し率（震災後）
Rate after March, 2011

100 ％
90
80
70
60
50
40
30
20
10
0

北海道
Hokkaido

山形
Yamagata
秋田
Akita
福島
Fukushima
茨城IbarakiTochigi
栃木
Gunma
群馬
Saitama埼玉Tokyo
東京（23区・多摩）

Hokkaido
北海道

100％
90
80
70
60
50
40
30
20
10
0

青森
AomoriIwate
岩手
Miyagi宮城(c) Rate of Overlook

東京（伊豆諸島）Tokyo(Izuislands)
千葉
Chiba
神奈川
Kanagawa
長野
Nagano新潟（佐渡以外）
Niigata
静岡
Shizuoka

的中率（震災前）
Rate before March, 2011
的中率（震災後）
Rate after March, 2011

東京（伊豆諸島）Tokyo(Izuislands)
千葉
Chiba
神奈川
Kanagawa
Nagano長野
Niigata
新潟（佐渡以外）
Shizuoka静岡(b) Rate of Missing A

Yamagata
山形
秋田
Akita
Fukushima
福島
Ibaraki
茨城Tochigi
栃木
Gunma
群馬
Saitama埼玉Tokyo
東京（23区・多摩）

Hokkaido
北海道

青森
AomoriIwate
岩手
Miyagi宮城(a) Rate of Hit
100 ％
90
80
70
60
50
40
30
20
10
0

Figure 6: Rates of hit, missing, overlook by prefecture
before and after the Main March 2011 quake
From the above, the rough tendency is that the hit rate decreased and overlook andmissing A rate increased with no major difference in missing B rate in Hokkaido
and Tohoku districts. The increase in the overlook rate in Iwate and Miyagi
Prefectures is considered to be largely affected by the decrease in the number ofseismometers available in the coastal area. In Ibaraki and Tochigi Prefectures,
where EEWs were relatively frequently issued, the hit rate increased and overlook
rate decreased after the great earthquake, indicating higher accuracy. The
accuracy of Tokyo 23 wards and Tama area and Saitama Prefecture decreased
with lower hit rate and higher overlook rate although they are far away fromTohoku district. In the regions with decreased accuracy after the Great East
Earthquake, Intention to use and consciousness of usefulness regarding EEWs
might presumably be decreased.

Secular changes in people’s consciousness regarding earthquake early warning
Secularsurvey
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regarding earthquake early warning-Based on national(2009-2012)
Japan-

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3.2 Intention to Use EEWConsidering the results in the previous section, the regular disaster information
survey in December 2012 asked comments on whether EEWs should positively be
issued in spite of possibility of missing warnings. 33.1% of the total responded“warnings should positively be issued in spite of possibility of missing warnings,”
52.5% responded “warnings should be issued in spite of possibility of missing
warnings,” resulting in 85.6% of respondents accepting missing warnings.
Figure 7 shows the cross-aggregation results between the reception experience
rate and intention to use considering missing warnings. As a result of chi-square
test, a statistically-significant difference was confirmed when p < 0.001. 40% of
those who have received EEWs responded “warnings should positively be issued
in spite of possibility of missing warnings.” The reception experience is assumed
to lead to positive intention to use. In order to study the effect of the decrease inaccuracy of EEWs on motivation for use, figure 8 plots the decrease value of the
hit rate after the great earthquake per prefecture against the rate of answering“warnings should positively be issued in spite of possibility of missing warnings”
in the same prefecture. This figure indicates that the decrease in the hit rate do notdirectly cause intention to use EEWs to decline because there is no correlation
between the two.
0%

20%

40%

60%

80%

100%

Should positively be
issuedShould be issued

Actually received（N=1,436)

Should not
positively issued
Should never be
issuedNo idea, haven’t
experienced
No idea, notinterested in

Have not received(N=1,301)
No idea(N=263)Figure 7: Reception experience and intention to use considering missing warnings
Approval rate for positive
issuance as of 2012

100

(%)

80
60

y = 0.0242x + 32.755
R² = 0.0117

40
20
0

-50

0

50

100

Decrease value of hit rate after earthquake (%)

Figure 8: Relationship between decrease value of hit rate after the greatearthquake and approval rate for positive issuance342

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4. Analysis of Expectations for EEWs
Finally, this section analyzes the secular changes in expectation for EEWs basedon the results of the regular disaster information survey from 2010 to fiscal 2012.
Figure 9 shows the answer rate of choices to the question “what should be done inorder to make EEWs more easy to use?” The most popular answer in 2010 is“automatically turn on deactivated TV or radio to receive warnings” at 56.0%.
However, the rate of this answer decreases together with “make warnings
receivable by every kind of cell phones.” This seems to be the effect of the recent
increased rate of receiving the warnings using cell phones. The rates of “tellearthquake intensity” and “tell after how many seconds the shock will occur”
increased from 2011 to 2012 after the Great East Japan Earthquake. The rate of“tell earthquake intensity” is the highest among all choices in 2012 at 55.6%. The
motivation for more positively using EEWs enhanced after the March 2011 quake,
resulting in desire to know predicted intensity and time until ground motion
arrives. Currently, EEW for the general public don’t tell predicted intensity or
time until ground motion arrives, whereas EEW for advanced users inform of
these information. It means interests in the information only for advanced users
are increasing recently. Meanwhile, the rate of “want to know what to do
specifically when receiving EEWs” decreased significantly from 41.8% in 2009 to
26.8% in 2012. It is possible that situations during earthquake disasters are moreclearly imaged after the Great East Japan Earthquake but interest in proper
behaviors is waning due to easy understanding. Nevertheless, this image is likely
to include incorrect understanding for proper behaviors, so awareness for proper
behaviors should continuously be raised. Interest in behaviors when receiving
EEWs need be enhanced by means of training and materials of EEWs in regions
to which EEW have rarely been issued so far and where the reception experience
rate will fluctuate at a low level in the future, such as western Japan.
5. Conclusions
In this paper, the secular changes in the rates of recognition and reception
experience of EEWs were analyzed by comparing the result of the regular disaster
information survey from fiscal 2009 to 2012. In addition, the regional differencesof the awareness of the general public regarding the accuracy of EEWs wereanalyzed by comparing issuance history of EEWs nationwide thus far with theresults of the regular disaster information survey. Finally, the secular changes in
expectations of citizens for EEWs were clarified. Major findings obtained are as
follows.
• The rates of recognition and reception experience of EEWs increased
significantly after the Great East Japan Earthquake.
• The recognition rate exceeded 50% as of 2009 in all districts, while the reception
experience rate showed larger regional differences than the recognition rate.
The reception experience rate in western Japan is as low as approximately
20%.
• It was confirmed that the rates of recognition and reception experience tend to
rapidly increase when issuance times of EEWs increases. The both rates

Secular changes in people’s consciousness regarding earthquake early warning
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changesin people’sinconsciousness
regarding earthquake early warning-Based on national(2009-2012)
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• The rate of responding “warnings should positively be issued in spite of thepossibility of missing warnings” was as high as 85.6%.
• The decrease in the accuracy of EEWs did not clearly affect intention to use of
EEWs. Meanwhile, reception experience leaded to positive intention to use.
• Needs for information about predicted intensity and time until ground motion
arrives are increasing for the future EEW. Needs for information about “whatto do specifically after EEW“ is decreasing, suggesting a possibility of
insufficient understanding for proper behaviors. Interest in behaviors when
receiving EEWs should be enhanced in the regions where EEWs rarely issued.
Note that the analysis in Section 3 focuses on whether EEWs is issued or not toeach prefecture. However, the relationship between whether or not EEWs was
issued before the arrival of the main shock and the awareness of the general publiccannot be analyzed due to the constraints of data. In addition, the relationshipbetween the observed intensity in each prefecture and the awareness of the generalpublic is not analyzed. Further analyses considering these points are required as
future issues.
ACKNOWLEDGEMENT
Regular disaster information survey was conducted using donation for the courseof cooperation between lifeline companies and mass medias at the CIDIR, forwhich the authors are deeply grateful.
REFERENCES
Japan Meteolological Agency, Earthquak Early Warning, ,http://www. Jseisvol.kishou.go.jp/eq/EEW/kaisetsu/joho/
Japan Meteolological Agency, Press Release: Issurance of Earthquak Early
Warning after the Great East Japan Earthquake, April 28, 2011.
Japan Meteolological Agency, Press Release: Improvement of Earthquak Early
Warning, Japan, August 10, 2011.
Japan Meteolological Agency, Search Engine of Intensity Database,
http://www.seisvol.kishou.go.jp/eq/shindo db/
M. Ohara, K. Meguro, and A. Tanaka, “A study on Regional Tendency ofEarthquake Early Warning Proveded to the Public in All Parts of Japan,”
Proceedings of the 32th JSCE Earthquake Engineering Symposium, Japan
Sociery of Civil Engineers, 2012.

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Prediction on sediment related disasterthrough the satellite rainfall data
Yoshikazu SHIMIZU1 , Toshio OKAZUMI2, and Tadanori ISHIZUKA3
1
Senior Researcher,International Centre for Water Hazard and Risk Management under the auspicesof UNESCO (ICHARM),
Public Works Research Institute (PWRI), Japanshimizu@pwri.go.jp
2
Chife Researcher, ICHARM, PWRI, Japan
3
Chief Researcher, Volcano and debris-flow Research team, PWRI, Japan

ABSTRACTIn this study, the sediment-related disaster prediction method currently practiced
in Japan was coupled with satellite rainfall data and applied to domestic largescale sediment-related disasters. The study confirmed the feasibility of thisintegrated method.
In Asia, large-scale sediment-related disasters which can sweep away an entire
settlement occur frequently. Leyte Island suffered from a huge landslide in 2004,
and Typhoon Molakot in 2009 caused huge landslides in Taiwan. In the event ofthese sediment-related disasters, immediate responses by central and local
governments are crucial in crisis management.
In developing countries, however, only limited rainfall information is available
from regular and radar rain gauge networks. For this reason, the International
Centre for Water Hazard and Risk Management (ICHARM) of the Public Works
Research Institute has developed and has been disseminating the Integrated Flood
Analysis System (IFAS) to establish flood warning and evacuation systems indeveloping countries with insufficient hydrological information.
This study confirmed that it is possible to deliver information on the risk level ofsediment-related disasters such as slope failures and debris flows in addition toflood warning by IFAS. The prediction method tested in this study is expected toassist sparsely gauged areas in timely emergency responses to rainfall-induced
natural disasters.
Keywords: prediction, shallow landslide, debris flow, satellite rainfall, IFAS
1. Introduction
In Japan, projects to control sediment and erosion (hereinafter “sabo”) have been
implemented continuously since the late 1800s. These projects have contributed toprevention of sediment disasters by means of structural measures such as sabodams. However, hazardous areas in which five houses or more are at immediaterisk of sediment disaster amount to approximately 210,000, and in only about
20% of them have prevention measures been implemented. On top of this, there

345

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Vietnamare approximately 520,000 areas where the risk of sediment disaster exists. Thus,taking infrastructure-based measures for all these disaster risk areas would require
enormous amounts of time and cost.
Consequently, “non-structural measures”, i.e., prediction, forecast, and control
measures when disasters occur, must be taken to save human lives.
2. Measures and policies on the prevention of sediment related disaster inJapan
In Japan, new residential areas have been developed in suburban areas, and suchdevelopment leads to a yearly increase in the number of sediment disaster-prone
areas. Thus, in addition to infrastructure-based approaches, such as construction toprevent sediment disasters, it is important to take activity-based measures,
including identification of sediment disaster risk areas, establishment of warningand evaluation systems in risk areas, and control of the location of new housing inhazardous areas. The Sediment Disaster Countermeasures for Sediment DisasterProne Areas Act took effect on May 8, 2000, to implement these holistic
approaches. The following are some of the measures listed in this law.
2.1 Implementation of basic surveys and designation of sediment disasterprone areas
The measures listed below must be implemented to identify areas that are at riskof sediment disaster and establish a site-specific warning and evacuation systemthat are appropriate to cope with the characteristics of such disasters (e.g., they
may occur suddenly without any signs, it may cause human damage, etc.) for
individual locations.
1) Implementation of basic surveys2) Designation of sediment disaster-prone areas and special sediment disasterprone areas.
2.2 Establish the early warning system and regulation of land-use
The following measures must be implemented for sediment disaster-prone areasand high-risk sediment disaster-prone areas.
1) Disaster-prone area:
Establishment of an early warning system
2) High-risk disaster-prone area:
Permit system for certain development activities
Structural regulations for buildings
Recommendation of building relocation
3. Methodology of setting sediment related disaster warning and evacuation
critical rainfall
Mayors of municipal governments are responsible for taking timely, appropriate
response measures, such as calling for disaster prevention activities and issuing

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evacuation advisories to local residents, if the risk of sediment disaster due toheavy rainfall becomes dangerously high. To help mayors, the Sediment Disaster
Warning and Evacuation Critical Rainfall (the Cooperative Proposal) has beendeveloped jointly by the Sabo (Erosion and Sediment Control) Department of theRiver Bureau with the Information Division of the Meteorological Agency of the
Ministry of Land, Infrastructure and Transport as judgment criteria. Mayors areadvised to use the Cooperative Proposal to set “critical lines”.
Critical lines are set based on assessment of the risk of a sediment related
disaster within a specified area based on rainfall. It is important to note that thisassessment considers only rainfall, and does not consider local topography,
geology, vegetation and other factors of individual locations.
3.1 Target phenomenon
The target phenomena are debris flows and concentrated cliff collapses. A
concentrated cliff collapse is defined as “cliff collapses that occur within a
specified range near the peak of a series of rains in a case where the soil-water
index is at or above a specified value.”
3.2 Rainfall indices
A criterion is set by combining two indices: the short-term rainfall index andlong-term rainfall index. The short-term rainfall index is defined as the 60-minutetotal rainfall; the long-term rainfall index as the soil-water index, which is an
estimation of the retention status of fallen rainfall in soil (for a detailed
explanation of the soil-water index, see Attachment 1, and obtain information
provided as necessary from the regional meteorological observatory, etc.).
3.3 Setting procedure of Critical Line

Figure 1: Image of critical line (CL) and rainfall index

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The sediment disaster occurrence risk critical line (CL) is set as the boundary
between two types of zones. The first type is called the “low-risk zone”, where theoccurrence probability of rainfall that is unlikely to cause a sediment disaster ishigh. This probability is determined in reference to past rainfall that did not cause
a sediment disaster (no-occurrence rainfall). The CL is set between a safe zone
and a high sediment disaster risk zone in consideration of the occurrence
probability and past records of sediment disasters as well as response measures,such as evacuation advisories, taken at the time.
3.4 Maintenance of Critical Line
Critical Line is revised as necessary based on new rainfall data and disaster dataobtained after their establishment.
4. Prediction on sediment related disaster through the satellite rainfall data
In general, there are not enough rainfall gauge stations in developing countries.
Therefore national and local governments have little information to determine therisk level of water induced disasters in their service areas.
In consideration of this situation, a feasibility study was conducted on theJapanese prediction methodology for sediment related disasters by using satellite
based rainfall data.
4.1 Satellite based rainfall data
Table 1: Specification of satellite based rainfall data
Products
Providers
Coverage
SpatialresolutionTimeresolution
Delay
Datum
Providing
periodSensor

3B42RT
NASA/GSFC
50N~50S

CMORPH QMORPHNOAA/CPC
60N~60S
60N~60S

GSMaP
JAXA/EORC
60N~60S

0.25°

0.25°

0.25°

0.1°

3 hours

3 hours

0.5 hour

1 hour10 hours

15 hours

2.5 hours
WGS
RecentDec. 2002~
2days

4 hoursMar. 2000 ~Mar. 2000

TRMM/TMI
Aqua/AMSR-E
AMUS-B
DMSP/SSM/IIR
ADEOSII/AMSR
Table1 shows near-real-time satellite rainfall data products. The products havedifferent space and time resolutions, using different sensors and algorisms. In thisstudy, we used GSMaP provided by JAXA and 3B42RT by NASA.
TRMM/TMI
Aqua/AMSR-E
AMUS-B
DMSP/SSM/IIR

348

TRMM/TMI
Aqua/AMSR-E
AMUS-B
DMSP/SSM/IIR

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4.2 Case study on prediction of sediment related disaster through the satellite
rainfall data
In July 2009, a high-density sediment related disaster, or a debris flow, occurredin Hofu City of Yamaguchi Prefecture, Japan. This event was calculated by using
the Japanese standard methodology such as like third section, and then analyzed
for its feasibility.
4.2.1 Overview of phenomenon
Figure 2 shows hourly rainfall data and soil water index between the early June
and the late August in 2009 at Manao hydrological station of MLIT, which islocated near the disaster-hit area where many people were victimized.
The monthly rainfall reached 688mm in July 2009, exceeding July’s average
rainfall of 294.9mm between 1981 and 2010. In addition, hourly rainfalls of over
30 mm were recorded before July 21, when multiple sediment disasters occurred,
and the total rainfall between July 1 and July 20 reached 213 mm.
Hofu city, Yamaguchi prefecture Manao gauged Station（MLIT）
300

0
10

250

30

Soil Water Index

200

40
150

50
60

100
70

Hourly Rainfall (mm/h)

Soil Water Index (mm)20

Hourly Rainfall

80
50
90

0
/3

4

/8

/2
/8

20
09

8
/1
/8

09
20

/1
20
09

/8

2

6
8/
20
09

9/

1
/3
20
0

20
09

/7

/2

5

9

/7

/1
/7

20
09

/1

20
09

/7

3

7
7/
20
09

9/

1
9/
20
0

20
0

7/

/2

5

9
/6

/1
/6

20
09

3
/1

20
09

/6

6/

6/

20
09

9/
20
0

9/
20
0

7

100

1

0

Date (UTC)

Figure 2: Rainfall data at Manao rain gauged station（Jun 2009〜Aug 2009）

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4.2.2 Result of calculation of satellite rainfall data and compared groundbased rainfall data’s
21 July 2009 Hofu city, Yamaguchi Prefecture

5km mesh code：34310209

100

Hourly rainfall

Critical line

Heavy rain warning

Heavy rain advisory80

12pm July 21

60

40

20

0
0

50

100

150
Soil Water Index

200

250

300

Hourly rainfall - Soil Water Index Manao gauged Station （MLIT）
20 July 〜23 July 2009
250

80

70

Hourly Rainfall
Ground based rainfall

60

Soil Water Index (mm)

3B42RT
GSMaP original

150

50

GSMaP corrected
40

100
30

Hourly rainfall (mm/h)

200

20
50
10

0

2009/7/20 0:00

0

2009/7/21 0:00

2009/7/22 0:00

2009/7/23 0:00

Time (UTC)

Figure 3: Comparing between ground based and satellite based rainfall data
Figure 3 shows sediment related disaster risk calculated based on the rainfall data
between July 20 and July 23, 2009.
The upper graph of Figure 4 shows snake curves based on ground and satellite
rainfall, and the lower graph shows hourly rainfall and soil water index. In bothgraphs, the thick solid line is ground based rainfall, the thick dashed line is350

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3B42RT satellite rainfall, the light solid line is GSMaP original rainfall, and thelight dashed line is GSMaP corrected rainfall. Corrected GSMaP rainfall isaverage rainfall of the given hour and the hours before and after that inconsideration of the movement of the rainfall area.
The snake curves from satellite rainfall data look relatively flatter than thosefrom ground based rainfall data because of their underestimating tendency. On theother hand, in terms of soil water index, the curves from both types of data show avery similar temporal trend.
5. Conclusion
In this research, we have conducted a feasible study to compare grand based
rainfall data with satellite based rainfall data for prediction of sediment related
disasters, using a Japanese standard methodology.
As Figure 3 shows, hourly satellite based rainfall has an underestimating
tendency compared with ground based rainfall data. In addition, due to time
resolution and delay from real time, it was found not feasible to use satellite data
for early warning systems though it may still be useful in risk management by
central and local governments as information to facilitate crisis response by the
public. As the Global Precipitation Measurement (GPM) Plan progresses, spatial
resolution, time resolution and accuracy of rainfall data should be further
improved and will be more effective in practical use.
We are planning to conduct longer term analysis and examine applicability toother regions in addition to studying when, where and how this methodology canbe best used..
Reference
Osanai, N., Shimizu, T., et.al, Japanese early-warning for debris flows and slope
failures using rainfall indices with Radial Basis Function Network, Landslides,
Volume 7, Issue 3, 325-338
JAXA EORC, TRMM JAXA, http://www.eorc.jaxa.jp/TRMM/index_e.htm
Nishi, M., et.al, 2009, July 2009 northern Kyushu and Chugoku regional heavy
rainfall induced sediment related disaster at Hofu city, Yamaguchi Prefecture,
Civil Engineering Journal, Vol.51, No.9, 4-7 (in Japanese)
Okada, N., et al., 2001, Soil water index, Weather, vol.48, no.5, 349-356, (inJapanese) .

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Effect of foreign government advisories on
foreigners’ post-disaster action
after the 2011 Great East Japan Earthquake
Akiyuki KAWASAKI1, Michael HENRY2,
Ichigaki TAKIGAWA3, and Kimiro MEGURO4
akiyuki@iis.u-tokyo.ac.jp
1
Project associate professor, International Center for Urban Safety Engineering,
Institute of Industrial Science, the University of Tokyo, Japan
2
Assistant professor, Division of Field Engineering for the Environment,
Faculty of Engineering, Hokkaido University, Japan
3
Assistant professor, Creative Research Institute, Hokkaido University
4
Professor and Director, International Center for Urban Safety Engineering,
Institute of Industrial Science, the University of Tokyo, Japan
ABSTRACT
Immediately after the Great East Japan Earthquake, many foreign governments
issued advisories to their citizens residing in Japan to relocate to the western partof the country or to leave Japan entirely, whereas other governments issued noadvisory at all. The post-disaster response of many foreigners was to flee Japan,
but it is not clear how much influence the government advisories had on thisdecision making or if other factors may have been involved. Through aquestionnaire survey given to foreigners residing in the Kanto region at the timeof the disaster, the relationship between the advisories issues by overseas
governments and the behavior of foreigners residing in Japan was investigated inorder to examine the differences among people who did and did not follow therecommendations of their government. Three sample groups were created basedon the foreign governments’ advisory level, and the effect on post-disaster action
was examined and compared to other characteristics.
Keywords: post-disaster action, relocation or evacuation advisory, foreigner,
information
1. INTRODUCTION
After the 2011 Great East Japan Earthquake disaster, many important issues arosewith relation to the differences in the post-disaster response of foreign
governments. Notably, some governments issued a variety of official advisories totheir citizens residing in Japan, such as orders to evacuate areas around the
Fukushima Daiichi nuclear power plant, recommendations to consider evacuationfrom eastern Japan (including Tokyo), and temporary travel restrictions on
visiting specific areas of Japan or to travel to Japan in general. On the other hand,
many countries did not issue any particular advisory.

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October
2013, Hanoi,
Vietnam
October
2013, Hanoi,
VietnamWhat was the relationship between the advisories issued by foreign countries in
response to the 2011 Great East Japan Earthquake disaster and the post-disasterevacuation action of their citizens? Similarly, what were the reasons why
foreigners decided to remain in the Kanto region despite the recommendation of
their home country’s government to evacuate or relocate? To understand these
relationships, an analysis of the results of a questionnaire survey taken of
foreigners residing in the Kanto region of Japan at the time of the earthquake wascarried out based on the advisory level of foreign governments around the world.
First, the responses of foreign governments in the aftermath of the earthquake areorganized and divided into three groups based on the level of their advisory. Next,
the actual post-disaster actions, along with the timing and reason for those actions,of respondents are analyzed considering the government advisory level.
2. SUMMARY OF GOVERNMENT ADVISORIES
2.1 Temporary closure and relocation of embassies in Tokyo
As of March 23rd, 2011, the Japanese Ministry of Foreign Affairs (MOFA)
reported that 25 countries had temporarily closed their embassies. In addition to
the announced countries, it was reported that other countries such Thailand,
France and Iraq also closed their embassy, resulting in closure of 29 out of the 150
embassies. In contrast to the embassies of Asian countries, which generally
continued operations after the earthquake, a relatively large number of Africancountries closed their embassy. These embassies gradually resumed operations inTokyo, with all of them returning to service by the end of May 2011.
2.2 Foreign government-issued advisories
A summary of the advisories issued by governments after the earthquake is shownin Tables 1 and 2. This information was collected from a variety of sources:
MOFA (as of April 12th, 2011), major foreign media such as Reuters and ABC
news, the websites of MOFA and embassies, and via direct inquiry to embassies.
In this paper, the advisories are divided into four major categories: “evacuationfrom a specific area,” such as from within x kilometers of the Fukushima Daiichi
nuclear power plant; “leave Japan,” including travel from eastern Japan; “travel
restrictions to specific areas;” and “travel restriction to Japan,” intended for
citizens planning to visit Japan.
After the earthquake, a variety of notices and announcements were officially
issued not only from embassies but also from government representatives such as
prime ministers, foreign ministers, or ministers of foreign affairs. For the purposeof this paper, those notices and announcements related to evacuation or travel
restrictions are all included as official advisories.

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October 2013, Hanoi, Vietnam

Australia

SerbiaDenmark

Bulgaria

Portugal

Netherlands

Austria

Switzerland

Italy

FranceEnglandSingapore

TaiwanHong Kong

Thailand

Table 1: Countries who advised leaving Japan

Evacuate from a○ ○ ○ ○ ○ ○ ○ ○ ○ ○○○specific area
Travel restrictions○○ ○ ○ ○○○
to specific areas
Evacuate from○ ○ ○○4 ○1 ○ ○3 ○2 ○5 ○ ○ ○ ○ ○Japan
Travel restriction○4 ○ ○○2 ○5 ○ ○to Japan
1
Tokyo 2Metropolitan area 3Greater area of Tokyo and Yokohama 4North ofTokyo 5Kanto and areas north

China
S. Korea
Philippines
Malaysia
India
USA
CanadaGermany
Beglium
NorwaySwedenFinland
Croatia
Hungary
PolandRomania
Slovakia
Slovenia
RussiaSpain
New ZealandTurkeyTable 2: Countries who advised region-specific relocation in Japan

Evacuatefrom aspecific area

○ ○ ○ ○ ○ ○ ○ ○Travelrestrictions to ○specific areas

○ ○

○

○

○

○

○

○ ○ ○

○

○

Evacuatefrom Japan
Travelrestriction to
Japan

○
1

○
4

○ ○ ○ ○

○
6

○ ○ ○

○
1

○ ○ ○ ○ ○ ○ ○ ○○4Tokyo 4North of Tokyo 6Tokyo and northern Honshu

2.3 Timing of advisory issuance
When examining the timing of advisory issuance, it can be seen that many
countries responded promptly in the aftermath of the earthquake. On March 11th,
the day of the earthquake, the National Tourism Administration of The People’s
Republic of China issued an advisory emphasizing that Chinese citizens should
stay away from affected areas such as Fukushima Prefecture and Sendai City. The
Effect of foreign government advisories on foreigners’ post-disaster action
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following day, a variety of countries – including South Korea, Taiwan, Hong
Kong, Malaysia, Singapore, Canada, the United States, England, and France –issued various advisories for evacuation and restrictions on travel to Japan.
Those advisories – particularly those relating to travel restrictions – were
eventually lifted or gradually relaxed. For example, Denmark lifted a voluntary
ban on traveling near Tokyo on April 16th. On the following day, England
removed Tokyo from its designated list of areas with a travel ban. Furthermore,on April 14th the United States lifted a travel warning to areas in Japan, excluding
the area within an 80 kilometer radius of the Fukushima Daiichi nuclear power
plant (which remained restricted), as the situation improved. However, somecountries such as South Korea, Taiwan, Hong Kong, and Australia continued theirtravel restriction advisories until June.
Overall, it could be seen that while the issuance of advisories was concentrated ina short period immediately after the earthquake, the period until those advisories
and restrictions were lifted or relaxed varied over a long period of several months,
depending on the country.
3. SURVEY METHODOLOGY AND SAMPLE CATEGORIZATION
3.1 Survey contents and distribution
An online survey focusing on people in the Kanto region of Japan was carried out
to understand the information collection behavior and post-disaster action after the2011 Great East Japan Earthquake disaster. Complete details of the survey
contents and distribution can be found in Kawasaki et al. (2012). The survey
questions analyzed in this paper are summarized in Table 3.
Table 3: Selected survey contents analyzed in this paper
Theme

Question contents
Post-disaster action (remain in Kanto area, relocate to another
Post-disaster area of Japan, or leave Japan)
Timing of decision on post-disaster action
actionReason(s) for post-disaster action decision making*
Demographics Nationality* This question allowed for multiple responses
3.2 Sample characteristics & categorization
A total of 1,357 responses were collected, of which 497 (36.6%) were fromJapanese and 860 (63.4%) from foreigners representing 73 countries. Of the 860
responses from foreigners, 856 valid responses were identified: 492 from Asia, 24
from Oceania, 178 from Europe, 80 from North America, 52 from Central andSouth America, 12 from the Middle East, and 18 from Africa.
Based on the level of government advisories summarized in Tables 1 and 2, thesample of foreigners was categorized into three groups. After categorization

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October 2013, Hanoi, Vietnam“Group 1” consists of 207 respondents from 13 countries whose governments
issued the most cautious advisory; “Group 2” consists of 510 respondents from 30
countries whose government issued a less cautious advisory; and “Group 3”
consists of 139 respondents from 29 countries whose government issued no
specific advisory.
4. RESULTS AND DISCUSSION
4.1 Post-disaster evacuation or relocation action
The results of post-disaster action by government advisory level are shown in
Figure 1. It could be seen that more cautious advisories lead to a greater numberof respondents evacuating and vice versa. This result was statistically significant
at a confidence level of 99%; that is, there appeared to be a correlation between
the level of advisory and the post-disaster action.
Left

100%

Relocated

Remained22%% respondents

80%

51%

40%
19%

60%
21%
40%

20%
59%

20%

29%

0%

N=856

Group 140%

Group 2

Group 3

(χ =36.10427, df=4, p<.01)
2

Figure 1: Effect of government advisory on post-disaster action
In Group 1, which issued the most cautious advisory, 71% of respondents
evacuated from the Kanto region; 51% of the total chose to leave Japan entirely
whereas 20% relocated to another area in Japan. In Group 2, which advised only
from specific areas such as the Tohoku region, a majority of the respondents(61%) evacuated from the Kanto region; 40% of the total chose to leave Japan
entirely while 21% just relocated within Japan. In contrast to the other two groups,
only 41% of Group 3 respondents decided to leave the Kanto region; 22% left
Japan entirely and 19% evacuated to other regions.
When examining the differences between these groups, it can be seen that thepercentage of respondents who evacuated Japan was considerably higher in Group
1 than in Group 3, while nearly double the percentage of respondents in Group 3
did not evacuate compared to Group 1. The results of Group 2 fell between thoseof Groups 1 and 3. This result indicates that the difference in government advisoryexerted a certain level of influence on respondents’ post-disaster action to relocate.

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4.2 Timing of post-disaster action
To examine the effect of government advisory on the timing of post-disasteraction, respondents who left Japan entirely or relocated to another area in Japan
during the two weeks following the earthquake were extracted. The results areshown in Figure 2. From the chi-square test we can conclude that there is no
statistically significant difference between the timing of post-disaster action andthe distributions of the respondents who relocated and those who left for all threegroups.
In Group 1, the cumulative percentage of respondents who made their decision to
relocate within 1 to 3 days of the earthquake was 53%; over the same period, 54%
of respondents decided to leave Japan. The cumulative value increased to 93%
and 85% for relocation and leaving, respectively, when the time period reached 1
week. From these results, it can be observed that the majority of respondents
made their decision to evacuate the Kanto region or Japan in a very short periodof time after the earthquake.
Group 1 (N=134)< 1 day

10%
7%

1日以内
43%
47%

< 3 days

40%
31%< 1 week< 2 weeks> 2 weeks

8%
15%
0%
0%

Group 2 (N=295)
3%
4%

1日以内
23%
30%

3日以内

4%
0%

3日以内

20%

53%
1週間以内
48%

1週間以内

Relocated
2週間以内(n=40)
Left
2週間後以上(n=94)

Group 3 (N=57)

19%
14%
2%
5%

Relocated
2週間以内(n=100)Left
2週間後以上(n=195)

37%
37%
47%

27%
4%
7%

19%

Relocated(n=27)
Left(n=30)

0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100%
% respondents% respondents% respondents22(χ2=2.2457, df=3, p=0.523)(χ =4.0251, df=4,
p<0.4026)(χ =3.5442, df=4,
p=0.4712)

Figure 2: Effect of government advisory on timing of post-disaster action
In Group 2, the most-cited period for making the decision for post-disaster action
was within 1 week (4 days to 1 week), as around half of the respondents decided
to either leave the Kanto region (53%) or Japan (48%). The cumulative
percentages at the time point were 79% for relocation and 82% for leaving Japan
entirely.
In Group 3, the cumulative percentage of respondents who decided to relocate
within Japan or evacuate the country entirely within 1 week were 78% and 67%,
respectively. However, the total number of respondents in this group who decided
to relocate or evacuate was much lower than the other two groups. The
percentages of people who took their action within 2 weeks (between 1 and 2
weeks) or after more than two weeks were slightly higher than for Groups 1 and 2,
which shows that the timing of decision making for respondents in Group 3 wasslightly later than in the other two groups.

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Overall, regardless of the countries’ advisory level, it appeared that people madetheir decision at a very early time after the earthquake: the majority of respondents
in Group 1 made their decision within 3 days, and even in Group 3 – where no
specific advisory was issued – most respondents made their decision within 1
week. However, this question only focused on the timing of the respondents’decision-making, and does not clarify whether they acted upon that decision,
whether they returned to the Kanto region later if they did, in fact, relocate or
evacuate, nor does it clarify the timing of their return.
4.3 Reasons for post-disaster action
Figure 3 shows the reasons why respondents made their decision to leave Japan,
relocate within Japan, or to remain in the Kanto area by government advisorylevel.
When examining Group 1, it can be seen that, among respondents who left Japan,
the most-cited reason was “family request” (60%) followed by “personal decision”(51%). The third and fourth most-cited reasons were “concern for babies orchildren” (16%) and “government directive” (14%), but these are cited by 35%
and 37% fewer respondents, respectively, compared to the second most-cited
reason. Among respondents who remained in the Kanto region, the primaryreason was “personal decision” (80%) followed by “job obligation” (54%). The
percentage of respondents who cited these two reasons in this group wasnoticeably higher than for respondents who relocated to another area of Japan orleft Japan entirely. For respondents who relocated within Japan, the results
generally tended to fall between the percentages of the other two groups (leftJapan or remained in the Kanto area).
Group 1 (N=207)
Personal
decisionGroup 2 (N=510)
56%
51%

Job
obligation

8%

Couldn't
evacuate

13%
7%
3%

Familyrequest8%

Concern forthe young
Government
directive
0%

54%

24%

80%
個人の判断

34%

乳児や子供たちへの配慮
Remained (n=61)

5%
10%
14%

Relocated (n=41)
政府による指示Left (n=105)
40%

60%

% respondents

40%

6%
6%
13%
4%
0%

家族・親戚
60% からの要望

8%
27%
16%

20%

55%
46%

業務命令

避難したかったが、できなかったGroup 3 (N=139)

80% 100% 0%

87%
59%
60%

業務命令

4%
3%

避難したかったが、できなかった

0%
0%

1%

1%

83%
個人の判断

5%
3%
8%
20%

6%

乳児や子供たちへの配慮
Remained (n=203)
Relocated (n=105)
政府による指示Left (n=202)

40%

60%

% respondents

21%

2%

家族・親戚
69%
からの要望
73%
18%
18%

29%

27%

63%
73%
19%

12%
0%
3%

80% 100% 0%20%

Remained (n=82)
Relocated (n=27)
Left (n=30)

40%

60%

80% 100%% respondents

Figure 3: Effect of government advisory on reasons for post-disaster action
The results for Group 2 were similar to those of Group 1. The most-cited reason
among both respondents who relocated to another of Japan and left Japan entirely
was “family request” (69% and 73%, respectively). This was followed by“personal decision” (55% and 46%, respectively). Again, there was a large
difference between the second and third most-cited reason for both groups:“concern for babies and children” (18% for both groups) was third andEffect of foreign government advisories on foreigners’ post-disaster action
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October 2013, Hanoi, Vietnam“government directive” (3% for respondents who relocated and 8% for
respondents who left) was fourth. Among respondents who remained in the Kanto
region, “personal decision” (83%) and “job obligation” (40%) were the most-cited
reasons, following the pattern shown by Group 1.
In Group 3, the trend among respondents who relocated or left Japan was similar
to that of Groups 1 and 2. The most-cited reasons were “family request” (63% and73%, respectively), “personal decision” (59% and 60%, respectively), and“concern for babies or children” (19% and 27%, respectively). However, among
respondents who elected to remain in the Kanto area, “personal decision” (87%)
was the most-cited reason, followed by “job obligation” (29%).
Although, when comparing the results of each group, a general trend can beobserved, it is difficult to fully clarify the true reason for the post-disaster action
because the most-cited reason – regardless of the action – was “personal decision,”
the meaning of which will vary widely between individuals. Respondents fromcountries which issued more cautious advisories had a slightly higher tendency tocite “government directive” as their reason for post-disaster action. However, it
was much less cited than “family request” or even “concern for babies or children.”
Furthermore, respondents who remained in Kanto despite their government’s
advisory to leave had a higher tendency to cite “job obligation.”
Finally, for respondents who evacuated from Japan even though their government
issued no specific advisory, “family request” was the most-cited reason and,
understandably, they did not cite “government directive.” In addition, “jobobligation” was clearly another reason why these respondents chose to stay in the
Kanto region.
5. CONCLUSION
This paper first gathered and sorted the previously undocumented information on
the temporary closure and relocation of embassies in Tokyo and the advisories
issued by foreign governments. Next, a combination of descriptive and statisticalanalyses were presented on how those advisories affected the post-disasterevacuation or relocation action of foreigners residing in the Kanto region of Japan.
A clear relationship between the level of government advisory and post-disasteraction was observed, as respondents from countries with more cautious advisories
appeared more likely to leave or relocate. However, further analyses must
consider these results together with the trend in other factors such as demographic
characteristics. A comprehensive analysis examining all these factors will be very
helpful in understanding the foreigner exodus phenomenon observed after the2011 Great East Japan Earthquake disaster.
ACKNOWLEDGEMENT
This research was partially supported by the Japan Society for the Promotion of
Science (Challenging Exploratory Research: “Investigation on disaster360

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information dissemination to foreigners after the great earthquake in Tokyo
metropolitan area”). In addition, the authors would like to express their gratitude
to everyone who cooperated with and supported this investigation.
REFERENCES
Kawasaki, A., Henry, M., Meguro, K., 2012. Analysis of disaster information
gathering behavior and language ability after the 2011 Tohoku Earthquake. 2012
New Technologies for Urban Safety of Mega Cities in Asia (ICUS Report 201203), Ulaanbaatar, Mongolia, 263-271.

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Further modification and working stressdesign using K-stiffness method on soft andhard foundations
Sowarapan DUANGKHAE1, Dennes T. BERGADO2, Pankaj BARAL3 and Barry
T. OCAY4
1
D. Eng. Graduate, Asian Institute of Technology, Thailand
2
Professor, Asian Institute of Technology, Thailand
bergado@ait.ac.th, dbergado@gmail.com
3
Research Assistant, Asian Institute of Technology, Thailand
4
M .Eng. Graduate, Asian Institute of Technology, Thailand

ABSTRACTIn this paper, current design methods for internal stability design of geosynthetic
and steel reinforced soil structures that are based on limit equilibrium concepts
were compared with working stress K-stiffness method based on the data obtained
from five full-scale reinforced embankments – two were constructed on hardground and three on soft ground. A common element of this data set is that all theembankments were backfilled with cohesive-frictional soils. These embankments
were reinforced with steel wire grids, metallic strips, hexagonal wire mesh andgeogrid materials particularly polyester (PET), polypropylene (PP) and highdensity polyethylene (HDPE). Generally, the reinforcement loads predicted by
AASHTO simplified method and FHWA structure stiffness method wereconsistently higher than those of working stress K-stiffness method and themeasured reinforcement loads for all cases of embankments on hard and soft
ground immediately after construction and at any periods after the completion of
the embankment. Moreover, the load distribution factor, Dtmax, and thereinforcement load prediction approach for geogrid and hexagonal wire meshreinforced embankments were also modified to be the same as both types ofembankment showed the same behavior on the distribution and magnitude ofreinforcement loads.
Keywords: reinforced embankment, soft ground, hard ground, load distribution
factor, limit equilibrium method and working stress method.

1. INTRODUCTION
For the internal stability design of geosynthetic and steel reinforced soil walls,
appropriate determinations of soil reinforcement loads and deformations arenecessary. The predicted reinforcement loads impact the strength and spacing
required for the reinforcement as well as the reinforcement length to resist pullout.
Two limit equilibrium methods can be found in recent North American design
specification to determine reinforcement loads: (i) the Tieback Wedge/Simplified363

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0ctober 2013, Hanoi, Vietnam

Method (AASHTO 2002), and (ii) the FHWA Structure Stiffness Method(Christopher et al. 1990). Current design methodologies uses limit equilibrium
concepts to calculate reinforcement loads. K-stiffness methods, which is a novel
working stress analytical method, as an original method (Allen et al, 2003) andmodified method (Miyata and Bathurst, 2007b) have been proposed asalternatives of the conservative limit equilibrium methods. Tin et al. (2011)
modified the K-stiffness method combining the effects of cohesion andsettlements. The content of this paper is successful to validate the K-stiffness
method for reinforced embankment on hard foundation and to compare thecorresponding performance of reinforced embankments on soft foundation.
Moreover, further modifications of K-stiffness method were made byinvestigating the effects of cohesion and settlement factors separately.

2. TEST EMBANKMENTS ON DMM IMPROVED SOFT FOUNDATION
AND HARD FOUNDATION
2.1 Reinforced embankments on DMM improved soft foundation
The reinforced soil test embankment with 6m vertical height, 19 m length and 6 m
width was erected at Wangnoi District of Ayuthaya province located 35 km northof AIT campus in Thailand (Lai et al. 2006 and Lai, 2009). The embankment was
backfilled with silty sand material and reinforced with hexagonal wire mesh
strips. Vertical precast concrete panel having a dimension of 1.5m x 1.5m x 0.15m
per panel/element was utilized as facing material of the wall. The compressible
foundation of the embankment was improved by DMM cement-clay piles using
jet grouting pressure of 20MPa. Circular soil-cement piles of diameter 0.6m wereplaced at 1.5m spacing at the middle section and 2 m spacing at the edge portionof the embankment in square pattern. Immense field instrumentation program was
employed to study the behavior and performance of the embankment and its
foundation. The sectional view of the embankment and location of
instrumentations are shown in Fig. 1. The foundation loads and settlements of theembankment at ground surface are plotted in Fig. 2.

Figure 1:364

Full schematic diagram of the instrumentation program at test
embankment (Lai, 2009; Lai et al, 2006)
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ICUS Report 73(Note: Solid symbols on piles
Hollow symbols on clay between piles)
Figure 2: Foundation loads and settlements with time on ground and on piles near
the centre of embankment (Lai, 2009; Lai et al, 2006)
2.2 Reinforced embankment on hard Foundation
A full scale reinforced earth embankment was designed and constructed by
Thailand Department of Highways (DOHs) and studied by Baral (2012). The
construction site is near the Highway No.11 in Phitsanulok Thailand. The backfill
soil consists of 50% lateritic soil and 50% silty sand with effective cohesion
ranging from 5 to 20kPa and effective friction angle of 37 degrees measured fromCU tension triaxial tests. The embankment consisted of reinforced soil slope(RSS) with 70 degrees from the horizontal with soil bags facing on one side. The
other side consisted of mechanically stabilized earth wall (MSEW) with concrete
panel facing. The RSS and MSEW test embankment were designed to 6 m ofheight, 15 m of width and 18 m of length. Three different types of polymericgeogrids reinforcement were installed, namely: polypropylene (PP), high density
polyethylene (HDPE) and polyester (PET) on the reinforced soil slope (RSS) side.
At the other side, the mechanically stabilized earth wall (MSEW) was constructedwith two types of metallic reinforcements such as metallic strip (MS) and steel
wire grid (SWG). The polymer and metallic reinforcements are shown in Fig. 3.
The vertical spacing of the reinforcement layer was 0.5 m and the length was 5 m(Upper layers of metallic strip from layer 7 to layer 12 have 5.80 m length). The
monitoring instruments are shown in Figs. 4 and 5 in plan and section views,
respectively, consisting of inclinometers, strain gauges, piezometers, plate
settlements and pressure cells. The metallic reinforcements consist of vibrating
wire strain gauges while fiber optic was utilized in the polymer reinforcements.
The hard foundation consists of interlayering of dense to very dense sand and very
Further modification
workingusingmethod
Further modification
and workingand
stressdesignstressusingdesign
K-stiffness
K-stiffness
method
on
soft
and
hard
foundations
on soft and hard foundations

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0ctober 2013, Hanoi, Vietnam

stiff to hard clay. The embankment was constructed to 6m in height for 125 days.
Subsequently, a surcharge of 20 kPa (1.2 m thick) was added until 186 days after
construction as shown in Fig. 5. The vertical settlements are plotted across thesection with polyester (PET) and steel wire grid (SWG) reinforcements of theembankment as shown in Fig. 6. A sensitivity analysis varying the effective
cohesion such as 5, 10 and 15 kPa were done, which indicated that 10 kPa
confirmed the predictions.

Figure 3: Polymer and metallic reinforcing materials

Figure 4: Plan of MSE wall/embankment

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Figure 5: Cross section of MSE wall/embankment indicating the location of themonitoring instrument

Figure 6 Compression profile of PET-SWG section at level 0.00m (bottom ofembankment) at 186 days after construction.

3. PREVIOUS TEST EMBANKMENTS ON UNIMPROVED SOFTGROUND FOUNDATIONS
To validate the original and modified K-stiffness method, the data obtained
previously from two test embankments constructed on unimproved soft Bangkok
clay at AIT Campus were used by Tin (2009) and Tin et al. (2011). One
Further modification
workingusingmethod
Further modification
and workingand
stressdesignstressusingdesign
K-stiffness
K-stiffness
method
on
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and
hard
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0ctober 2013, Hanoi, Vietnam

embankment was reinforced with steel grids with three different backfill materials
consisting of clayey sand (CS), lateritic soil (LS) and weathered clay (WC) as
briefly described in section 3.1. The other was reinforced with two types ofhexagonal reinforcement with silty sand backfill as briefly described in section 3.2.
Details of this embankment were described by Tin (2009) and Tin et.al (2011).
3.1 Steel grid reinforced wall/embankment
Shivashankar (1991) and Bergado et al. (1991 a,b) noted the behavior of a weldedwire wall with poor quality, cohesive-friction backfills on soft Bangkok clay. The
wall with a vertical wire mesh facing had the height of 5.7 m, length of 14.64 m at
the top and was divided into three sections along its length (Fig 7). The weldedwire mats were 2.44 m wide and 5.0 m long and consisted of W4.5 x W3.5 (6.07 x
5.36 mm diameter) size bars with 6 x 9 in. (0.15 x 0.225 m) grid opening. There
were seven mats instrumented with self-temperature compensating electricalresistant strain gauges for each section (Fig. 8). The vertical spacing between thereinforcement mats was 0.45 m. The backfill soil parameters as tabulated in Table
1 were deduced from CIU tests (Bergado et al, 1991a,b). The tensions in thereinforcement immediately after construction for the three types of backfills
consisting of clayey sand, lateritic soil and weathered clay were similar. Figure 9shows the typical values of reinforcement tension for clayey sand backfill.
Moreover, the surface settlements were also observed as plotted in Fig. 10. The
settlement profiles are also plotted at the bottom of Fig. 9. The soil profile of theembankment foundation consists of the uppermost 2.0 m thick weathered clay
layer underlain by 6.0 m thick soft clay layer and followed by 6.0 m thick stiffclay layer. The strength and compressibility parameters are given in Bergado et al.
(2000) and Bergado and Teerawattanasuk (2008).

Figure 7: Front (longitudinal) section of the welded wire wall (Bergado et al.,1991 a,b)

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Figure 8: View of the welded wire wall along section A-A (Bergado et al., 1991).
Note: mats 1 to 7 are instrumented; mats 8 to 14 are not instrumented.
Table 1: Parameters used to validate the data obtained from previous studies of
MSE structures at AITClayeysand

Lateritic
soil

Weatheredclay

Voottipruex(2000), Bergado
et al. (2000)
Reinforcement
type
PVC-coated wiremesh

Peak triaxial friction angle,tx’ (degrees)

24

25.2

24

30

Cohesion c’ (kN/m2)

10

20

30

5

17

19.3

16.3

18

Height of the wall H (m)

5.7

5.7

5.7

6

Equivalent height of uniform
surcharge pressure S (m)

0

0

0

0

Tributary area Sv (m)

0.45

0.45

0.45

0.5

Tensile stiffness Ji = J2%(kN/m)

36000

36000

36000

1140

Shivashankar (1991) ,Bergado et al. (1991)
Fill material type

Unit weight(kN/m3)

of

the

soil

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Figure 9: Variation of tensions in the longitudinal bars immediately after
construction and for different periods after construction (clayey sand)(Bergado et al., 1991 a,b)

Figure 10: Observed surface settlements (Bergado et al., 1991a,b)

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3.2

Hexagonal Wire Mesh Reinforced Wall

Voottipruex (2000) and Bergado et al (2000) investigated the behavior of fullscale hexagonal wire grid reinforced embankment constructed in AIT campus
with 6m height and 10 degree slope of gabion facing as shown in Fig. 11. The
facing consisted of large rectangular wire baskets with 1m by 1m in cross section
linked together and filled with rocks. Two types of hexagonal wire reinforcements,
namely: zinc-coated and PVC-coated with different apertures, were used in two
different sections along the length of the wall; and the vertical spacing between
the reinforcement layers was 0.5 m. The silty sand backfill was found to have aneffective internal friction angle of 30o and effective cohesion intercept of 5 kPa as
tabulated in Table 1 (Bergado et al., 2000; Bergado and Teerawattanasuk, 2008).
The strength parameters were deduced from CIU triaxial tests with soil specimen
compacted at maximum dry density (γdmax=18kN/m3) and optimum moisture
content (w=13%). The foundation subsoil layers were similar to the previously
mentioned steel grid reinforced embankment. The tensions in the PVC-coatedhexagonal wires with distance from the back face of the wall after construction
are given in Fig. 12. In addition, the corresponding surface settlements were also
observed for a period of 400 days as plotted in Fig. 13.

Figure 11 Front and section views of the hexagonal wire reinforced wall
(Voottipruex, 2000)

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Figure 12: Reinforcement tension of PVC-coated wire mesh at different periods
after construction (Voottipruex, 2000)

0

25

50

Duration (Days)

75 100 125 150 175 200 225 250 275 300 325 350 375 400

0-40

Settlement (mm)

-80
-120
-160
-200
-240
-280
-320
-360
-400

Figure 13: Observed ground surface settlement for embankment reinforced with
PVC coated wire mesh (Voottipruex, 2000)

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4. FURTHER MODIFICATION OF K-STIFFNESS METHOD FOR
REINFORCED EMBANKMENT ON SOFT AND HARD GROUND
The contribution of consolidation settlements to the reinforced embankment interms of distribution and magnitude of reinforcement loads as well as the lateral
movement of the embankment facing were observed in the reinforced
embankment case histories considered in this study. The embankments were
evaluated for their performance immediately after construction and at different
periods after completion of the embankment. Current design methods are notcalibrated and evaluated for possible post-construction load increase. Thus,
further modification of K-stiffness method to include settlement factor in addition
to cohesion factor is proposed. The zinc-coated hexagonal wire mesh reinforced
embankment section studied by Voottipruex (2000) were eliminated in theanalysis because these embankments were judged poorly on the criterion set by
Miyata and Bathurst (2007b) that the strain rates in the reinforcements should
decrease as the time after the construction increases. The above statement isparticularly applicable in this study for periods after the completion of theembankment when the ground has already attained considerable consolidation
settlement. When the ground attains stability i.e. during the end of the primaryconsolidation of the foundation, the increase in strain rates of the reinforcementsin the embankment should decrease.
The settlement factors, Фs, for the reinforced embankment case histories were
back-calculated from the maximum measured reinforcement load in theembankment for each period after the construction. Subsequently, the backcalculated settlement factors were plotted against the normalized settlement ratio
expressed as S/γH as shown in Fig. 18 for geogrid and hexagonal wire mesh, andmetallic reinforcements, respectively. Considering the type of reinforcements usedin the embankments and the range of values for the normalized settlement ratio,
S/γH, the settlement factor, Фs, is expressed as follows in Equations 1 and 2.
For geogrid and hexagonal wire mesh reinforced embankments:
For S/γH ≤ 4.00:

Фs = 1.37(S/γH) + 0.5(1)

For metallic reinforced embankments:
For S/γH > 4.00:

Фs = 0.076(S/γH) + 2.00

(2)where Фs is the foundation settlement factor, S is the magnitude of foundation
settlement at ground surface (mm) at any particular period, γ is the unit weight ofbackfill material (kN/m3) and H is the height of the reinforced embankment.

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As observed in Figs. 14 a,b to 17 a,b ,the maximum measured reinforcement loads
in the embankment were generally found at the base of the reinforced soil
embankment. Consequently, the load distribution factor, Dtmax, for geogrid andhexagonal wire mesh reinforced soil structure was further modified based on thisobservation. Subsequently, a uniform value of Dtmax equal to 1.0 was used startingfrom the normalized depth, (z +S)/(H + S), value of 0.4 to the base of thereinforced soil structure where the normalized depth, (z +S)/(H + S), value isequal to 1.0. The Dtmax for the metallic reinforced soil structure was not modified
and the load distribution factor still applies. Finally, with the further modificationsof the K-stiffness method, the maximum reinforcement load per unit width of theembankment is expressed in Equation 3.
Tmax = ½ K γ (H + S) Sv DtmaxΦgΦlocal ΦfsΦfbΦcΦs(3)where the terms have been defined previously.

(a) Comparison of measured and predicted reinforcement load

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ICUS Report 73(b) Comparison of measured and predicted reinforcement strain
Figure14a,b: Measured and predicted reinforcement load and strain for SWG
embankment withpoor quality backfills (clayey sand) on soft
ground (Shivashankar, 1991)(a) Comparison of measured and predicted reinforcement load

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October 2013, Hanoi, Vietnam
0ctober 2013, Hanoi, Vietnam(b) Comparison of measured and predicted reinforcement strain
Figure 15 a,b: Measured and predicted reinforcement load and strain for SWG
embankment with poor quality backfills (lateritic residual soil) on
soft ground (Shivashankar, 1991)(a) Comparison of measured and predicted reinforcement load

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ICUS Report 73(b) Comparison of measured and predicted reinforcement strain
Figure 16a,b: Measured and predicted reinforcement load and strain for SWG
embankment with poor quality backfills (weathered clay) on soft
ground (Shivashankar, 1991)(a) Comparison of measured and predicted reinforcement load

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October 2013, Hanoi, Vietnam
0ctober 2013, Hanoi, Vietnam(b) Comparison of measured and predicted reinforcement strain

Figure 17 a,b: Measured and predicted reinforcement load and strain for HWM(PVC-coated) embankment on soft ground (Voottipruex, 2000)

Figure 18: Back-calculated settlement factor, Фs for geogrid and hexagonal wire
mesh (HWM) reinforcements and metallic strip reinforcements versus
normalized settlement ratio, S/γH

5. CONCLUSIONSIn this study, current reinforcement load prediction methods were presented andapplied to assess the data obtained from four full-scale and fully instrumented
reinforced embankments previously studied in AIT. Two of these reinforced

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embankments were constructed on hard ground while the rest were constructed on
soft ground. These embankments were reinforced with steel wire grids, metallic
strips, hexagonal wire mesh and geogrid materials particularly polyester (PET),
polypropylene (PP) and high density polyethylene (HDPE). From the results of
the analyses performed on the embankment case histories, the following
conclusions were drawn:
1. The rate of increase in the magnitudes of the reinforcement load withrespect to time was minimal for the embankments on hard ground but
significant for the embankments on soft ground. The increase in themagnitude of the measured reinforcement loads especially at the base of
the embankment is therefore proportional to increase in value of groundsettlement.
2. Further modification of K-stiffness method was proposed by introducing aseparate settlement factor, Фs, on the modified K-stiffness method in orderto take into account the effect of foundation settlement on the magnitude
and distribution of reinforcement load.

REFERENCES
AASHTO, 2002. Standard specifications for highway bridges. 17th Edition.
American Association of State Highway and Transportation Officials (AASHTO),
Washington, D.C., U.S.A.
Allen T.M., Bathurst R.J., Holtz R.D., Walters D. and Lee W.F., 2003. A newworking stress method for prediction of reinforcement loads in geosynthetic walls.
Canadian Geotechnical Journal 40: 976-994.
Bergado D.T. and Teerawattanasuk C., 2008. 2D and 3D numerical simulations ofreinforced embankments on soft ground. Geotextiles and Geomembranes 26: 3955.
Bergado D.T., Sampaco C.L., Shivashankar R. et al., 1991a. Performance of
welded wire wall with poor quality backfills on soft clay. In ASCE
GeotechnicalEngineering Congress, Boulder, Colorado, U.S.A. pp. 909-922.
Bergado D.T., Shivashankar R., Sampaco C.L., Alfaro M.C. and Anderson L.R.,
1991b. Behavior of welded-wire wall with poor quality cohesive-frictional
backfills on soft Bangkok clay. Canadian Geotechnical Journal 28: 860-880.
Bergado D.T., Teerawattanasuk C., Youwai S. and Voottipruex P., 2000a. FE
modeling of hexagonal wire reinforced embankment on soft clay. Canadian
Geotechnical Journal 37: 1209-1226.
Lai Y.P., 2009. Performance and Behavior of Full Scale Reinforced Soil
Embankment/Wall on DMM Improved Foundation. D. Eng. Dissertation No.GE08-02, AIT, Bangkok, Thailand.

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K-stiffness
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and
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foundations
on soft and hard foundations379

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0ctober 2013, Hanoi, Vietnam

Lai Y.P., Bergado D.T., Lorenzo G.A. and Duangchan T., 2006. Full-scale
reinforced embankment on deep jet mixing improved ground. Ground
Improvement 10(4): 153-164.
Miyata Y. and Bathurst R.J., 2007a. Evaluation of K-stiffness method for verticalgeosynthetic reinforced granular soil walls in Japan. Soils and Foundations 47(2):319-335.
Miyata Y. and Bathurst R.J., 2007b. Development of the K-stiffness method forgeosynthetic reinforced soil walls constructed with c-ϕ soils. Canadian
Geotechnical Journal 44: 1391-1416.
Baral P., 2012. Simulation and Back-analyses of Design Parameters of MSE
wall/embankment on Hard Foundations using PLAXIS 3D Software. M. Eng.
Thesis No. GE-11-, AIT, Bangkok, Thailand.
Shivashankar R., 1991. Behavior of Mechanically Stabilized Earth (MSE)
Embankment with Poor Quality Backfills on Soft Clay Deposits, Including a Studyof the Pullout Resistances. D. Eng. Dissertation No. GT-90-03, AIT, Bangkok,
ThailandTin N., 2009. Factors Affecting The Kinked Steel Grid Reinforcement andModification of K-Stiffness Method in MSE Structures on Soft Ground. M. Eng.
Thesis No.GE-08-03, AIT, Bangkok, Thailand.
Tin N , Bergado DT and Voottipruex P., 2011. Modification of K-stiffness
method in MSE structures on soft ground. Geosynthetic International 18(5): 304321.
Voottipruex P., 2000. Interaction of Hexagonal Wire Reinforcement with Silty
Sand Backfill Soil and Behavior of Full Scale Embankment Reinforced with
Hexagonal Wire. D. Eng. Dissertation No. GE-99-1, AIT, Bangkok, Thailand.

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Survey of sub-surface cavities
in the liquefied groundcaused by the Great East Japan Earthquake
Ryoko SERA1, Yutaka KOIKE2 and Haruto NAKAMURA2,
Reiko KUWANO3 and Jiro KUWANO4
1
Geo Search Co., Ltd., Japanr-sera@geosearch.co.jp
2
Geo Search Co. Ltd., Japan
3
Professor, ICUS, IIS, The University of Tokyo, Japan
4
Professor, GRIS, Saitama University, Japan
ABSTRACT
A ground penetration radar survey was conducted on the roads of Urayasu-city,
Shinkiba-area and Narashino-city, all of which suffered damage caused by theground liquefaction during the Great East Japan Earthquake. A large amount of
fluidized sand, or sand boiling, was observed and a significant number ofsubsurface cavities were found in the liquefied ground. In this study, patterns of
sub-surface cavities observed in the disaster areas are reported andcharacteristics of sub-surface cavities obtained by the survey are analyzed. It was
found that cavities had a tendency to form near manholes and joints in the
pavement. These cavities have a larger area, but are thinner compared to cavities
normally observed in non-liquefied ground. Most of the cavities have been
repaired by either grouting or open-cut method.
Keywords: subsurface cavity, ground liquefaction, sand boiling, ground loosening
1. GROUND LIQUEFACTION ALONG THE TOKYO BAY COASTAL AREA
CAUSED BY THE GREAT EAST JAPAN EARTHQUAKEThe Great East Japan Earthquake of March 2011 (hereafter, “the Earthquake”)
brought about disasters unprecedented in magnitude to the nation of Japan.
Restoration work in the disaster area is still going on even after two years. The
Earthquake played havoc in areas other than East Japan which was directly hit by
the main quake and tsunami. The Japanese Geotechnical Society in its two reports
1) 2)
describe the ground foundation damage caused by the Earthquake as“extensive disasters that occurred in various locations covering a large
geographical area outside of East Japan”.

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October
2013, 2013,
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VietnamFig. 1: Subsurface cavity survey at a location where sand boiling and subsidence
occurred
The most notable among these are ground liquefaction disasters. They occurred
widely in reclaimed land sites along the coast of Tokyo Bay and in soft grounds
along the lower stream of the Tone River. The ground liquefaction took its toll on
the daily life of citizens by causing not only subsidence and tilting of stand-alone
private residential houses, but also causing damage to the undergroundinfrastructure. Sewer systems, for example, malfunctioned because of lifting,breaking, and clogging of sewer pipelines3), and cave-ins occurred on highways
and roads as shown in Fig. 1.
2. STATE AND ANALYSIS OF SUBSURFACE CAVITY FORMATION IN
LIQUEFIED GROUND AREAS
2.1 Location of subsurface cavities studied
This study was made based on data of 709 subsurface cavities which wereconfirmed through the inspection surveys covering a distance of 355km of paved
roads. Fig. 2 shows the locations of subsurface cavities, and Table 1 shows asummary of the subsurface cavities studied.
Narashino-city
Chiba Pref.
Urayasu-city
Chiba Pref.
Shinkiba
Koto-ward,Tokyo

Symbols:● Cavity
Locations
Surveyed
Road

JAPAN
Study area

Mar.11
2011

Fig. 2: Locations of subsurface cavities caused by ground liquefaction

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Table 1: Summary of subsurface cavities studied
Subsurface Cavity Survey (Paved Roads)
Municipality
Covered Distance (km)Number ofSurvey Period
Cavities
Road
Surveyed
Koto-ward
March 2011
5.75
47.78
54
Urayasu-city
April 2011-Aug 2012136.28307.23
528
Narashino-city
March- May2011
44.85
98.34
127
3 Municipalities in Total
142.03355.01709
2.2 Trend of subsurface liquefaction cavity formation
Cavities under roads are not only caused by ground liquefaction as described inthis study, but also by natural disasters like earthquakes or localized heavy rains.
There are other contributing factors under the normal situation as well, such as
breakage of degraded underground pipelines. Subsurface cavities form when avoid develops as soil particles or subbase materials wash away or settle due toconsolidation for some reason. Cavities thus formed expand over time, and when
the strength of the pavement exceeds its limit, a cave-in ultimately ensues. After
frequent road cave-ins occurred in Tokyo in 1988, which became an object ofsocial concern, regular subsurface cavity inspection surveys have been introduced
on a nation-wide basis in Japan. Table 2 show a comparison between theliquefaction cavities covered in this study and normal cavities which are foundwith regular surveys.
Table 2: Comparison of cavities according to cause
Normal Cavities
Liquefaction Cavities
Occurrence ratio
0.22 cavities/km
1.56 cavities/km
Area
1.68 m2
2.38 m2
AverageThickness
0.20 m0.13 mDepth
0.38 m0.37 m2.2.1 Cavity occurrence ratio
Fig. 3 summarizes the cavity occurrence ratio based on 709 subsurface cavities
which were confirmed in the areas that suffered ground liquefaction after the
Earthquake. The cavity occurrence ratio is defined as the number of subsurface
cavities found in 1km of survey distance. In the surveyed area, the occurrence
ratio is 1.56 cavities/km. This is more than 7 times compared with the cavity
occurrence ratio of 0.22 cavities/km 4) of the regular inspection surveys conductedin the 12 government ordinance cities in Japan. The surveyed roads can beclassified into 3 types, ‘arterial roads’, ‘sub-arterial roads’ and ‘community roads’.
They differ in the number of buried objects that contribute to cavity formation,and they have a different pavement structure. The cavity occurrence ratios are
1.06 cavities/km for arterial roads, 1.30 cavities/km for sub-arterial roads, and2.07 cavities/km for community roads.

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Survey of sub-surface
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0.22: Average of normal cavities
Arterial
roads

Liquefaction
cavities
Normalcavities

7 times

4.8 times

Community
Sub-arterial
roads
roads

5.8 times

Communityroads

9.4 times

Fig. 3: Cavity occurrence ratio in ground liquefaction area (total area, according toroad types)
2.2.2 Cavity area, thickness, and depth
Fig. 4 shows histograms of the liquefaction cavities area, thickness and depth.
Additionally average and maximum values are shown.
Area
Normal average: 1.68m2

Thickness

Depth

Normal average: 0.20m
Normal average: 0.38m

Average: 2.38m2, Max: 93.29,
Min: 0.15, Median: 1.43, Mode: 0.80

Average: 0.13m, Max: 0.78,
Min: 0.01, Median: 0.11, Mode: 0.05

Average: 0.37m, Max: 0.95,
Min: 0.06, Median: 0.38, Mode: 0.40

Fig. 4: Histograms of liquefaction cavities (Area, Thickness, Depth)
When compared with the average area of normal cavities, liquefaction cavities(2.38m2) are larger. Furthermore the shape of the distribution histogram showsthat more than 30% of the liquefaction cavities lie within the range of 1-2m2, and17 cavities have an area larger than 10m2. This distorted distribution results in arather large value for the average area. The average thickness is 0.13m and half ofthe cavities found had the thickness of less than 0.1m. If those cavities less than
0.2m in thickness were included, the number of cavities in this category exceeded
80% of the distribution. As a result, their average thickness is smaller than the
average thickness of normal cavities. Regarding the depth of the liquefaction
cavities, their average is equivalent to the average of normal cavities, which is
close to the lower subbase depth. Furthermore the distribution was found to beapproximately similar to the normal distribution. From this it was concluded thatthe cavity depth is not significantly different from the depth of normal cavities.
The conclusion in this study is that liquefaction cavities tend to have larger areaand smaller thickness.
2.3 Characteristics of liquefaction cavities
2.3.1 Large scale cavities
Analysis made in this study showed that liquefaction cavities tend to have larger
areas and are thinner. Fig. 5 shows pictures of typical cavities (No. 1-4), and very
thick cavities formed by liquefaction and damaged buried pipe and breakage of a384

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manhole (No. 5, 6).
No. 1: A large crack across andsubsidence
Size (W x L ): 5.7m x 5.7m
Cavity shape
Borehole Picture

No. 2: Occurred near a manhole
Size (W x L ): 3.7m x 2.3m
Cavity shape
Borehole Picture

Crack

ManholeSize (W x L ): 6.8m x 4.1m
Cavity shape
Borehole Picture

No. 5: Reoccurrence in repaired part of

the road, subsidence observed
Size (W x L ): 3.9m x 3.4m
Cavity shape
Borehole Picture

Asphalt

Pavement joint

Slag

CavityThickness 0.11m

Slag
ManholeCavityCavityCrushedrock
Thickness 0.12m

No.6: Occurred near a manhole
Size (W x L ): 1.8m x 1.8m
Cavity shape
Borehole Picture
Asphalt

Asphalt

Repaired part

Crushedrock

Slag

Asphalt

CavityThickness0.03m

Crushedrock
Thickness 0.05m

No.4: Occurred at a joint of the pavement

Size (W x L ): 1.9m x 3.8m
Cavity shape
Borehole Picture

Asphalt
Slag

Asphalt

CavityNo. 3: Occurred near a manhole

ManholeSlag

CavityThickness
0.73m

Thickness
0.62m

Crushedrock

Sand

Fig. 5: Examples of large scale cavities
2.3.2 Strings of cavities
One of the characteristics of the liquefaction cavities covered in this study is thepresence of “strings of cavities”, which are multiple cavities within a shortdistance. Although they form in very close proximity, each of those cavities in astring is an independent cavity. In fact, on the arterial roads, those strings ofcavities occurred in the same traffic lane within a distance of 50-100m. Along the
sub-arterial roads and community roads, such cavities were concentrated within adistance of 10-30m. In terms of a cavity occurrence ratio, this is equivalent tomore than 100 cavities per km. Such cavities were found at locations wherelarge-scale sand boiling occurred, or sometimes there were sewer mains directly
under the traffic lane. Fig. 6 shows borehole pictures of cavities found in thearterial roads. All the cavities eroded the road subbase or base course materials in
upward direction, and the bottom of these cavities is covered with fallen subbase
materials or fallen sand, and also the bottom of these cavities is not consistently
flat, the ground foundation underneath the pavement became undulated.
Asphalt

CavitySlagsubbaseCavityFallen slag,
Sand, etc

Fig. 6: Borehole pictures of a string of cavities in liquefied ground (14 cavities/100m)

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Survey of sub-surface
cavities in the liquefied ground caused by the Great East Japan Earthquake
Earthquake

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2.4 Condition of the inside and bottom of liquefaction cavities
The result of a survey carried out more than one year after the Earthquake showsthat there is sand ingress and groundwater inside many of the liquefaction cavities(Fig. 7). Although the groundwater level before the Earthquake was 1.5-3.0m2),
the groundwater at the bottom of 26 cavities had not yet receded and the waterlevel had been less than 1m (0.32-0.81m). Furthermore at the time of roadrestoration work, there were many pavement sections which showed soil ingressin what should have been the crushed rock layer, as shown in Fig. 7. These facts
show that liquefaction sent a large volume of sand upwards, an example of whichis shown in Fig. 8. The liquefaction at the time of the Earthquake left a strong
mark on the road structure in a wide area. In addition, loose soil was confirmed at
the bottom of many cavities. This condition indicates that the liquefaction brought
about not only the sand ingress into the road subbase, but also structurally
weakened the road beds in the affected areas.

Asphalt
Upper layers of road subbase
Lower layers of road subbase(originally crushed rocklayers)Remnants of crushed rock(small amount found)Fig. 7: Inside and bottom of liquefaction
cavities

Ingress of sand incrushed rock layer

Fig. 8: Cross section of pavement under repair(left) and borehole picture (right)

2.5 Analysis of the spatial distribution of liquefaction cavities
2.5.1 Age of reclaimed land and cavity distribution
The studied areas are reclaimed land sites where dredged sea sand was used asland fill, but the work was performed at different times. Though the reclamation
technique and ground improvement method were different depending on thelocation, it seems that reclamation work was carried out in two separate phases,
before and after the legislative revision of reclamation regulations. According toTable 3, the location and characteristics of cavities found in the studied areas, theolder the time of reclamation, that is, the older the time of community
construction and burying of underground piping system, the higher the number ofcavities. The number of cavities per ha is 5 times larger in older areas.
Table 3: Reclamation period and number of cavities
After 1975(after revision of the
Before 1974
reclamation regulation)

Number of Cavities
Reclaimed Area
Cavity Occurrence Ratio

386

600 cavities
1,214 ha0.49 cavities/ha

109 cavities
1,045 ha0.10 cavities/ha

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2.5.2 Conditions around liquefaction cavities
In order to know what kind of local conditions influenced the formation of the 709
liquefaction cavities, detailed data of the local conditions for each cavity werecollected in the inspection survey. The results confirmed that, in addition to thoselocations with large scale sand boiling and irregular road surface such as cave-ins,
cavities formed under pavement joints, close to gaps around the peripherals of
manholes, and around buried structures associated with drainage systems.
Examples of cavities in areas where ground liquefaction was observed are shownin Fig. 9 and Fig. 10.
Near a pavement joint

Near manholes

Pavement joint
0.3m
0.4m

CavityManholeManholeCavityFig. 9: Confirmed liquefaction cavities

Fig. 10: Conditions aroundliquefaction cavities

2.6 Analysis of liquefaction cavities and subbase materials
As the surveyed locations were along Tokyo Bay coast, 524 (70 %) out of thetotal 709 cavities were found in locations where iron and steel slag was used as
the lower subbase of the road structure. Slag is easy to obtain as byproduct of
pig-iron and steel making process. The use of slag as subbase material, however,involves a risk of dilation. For this reason, in Japan, quality control of slag
material is indispensable, and there is a JIS regulation especially for the use ofslag as subbase material. For the use of slag in the lower layers of subbase, amodified CBR (California Bearing Ratio) is specified for various possible cases.
In the studied areas it was inferred that the modified CBR value is the same as thatof crushed rock or higher, and slag with a more than sufficient strength andthickness was used.

↑Shallow ●(mode=0.17m)

Depth (m)↓Deep ●(mode=0.40m)

Subbase material:● Crushed rock

● Iron and steel Slag
○ Soil cement stabilization

Area (m2)

Fig. 11: Analysis of the relation between subbase material and cavity area
Fig. 11 shows the relation between the subbase material and the cavities area. The
analysis result shows the mode value of the upper end of cavities found in crushedrock subbase is more than 0.1m shallower than those of the slag subbase. It is
presumed that the strength intensified slag subbase prevented cavities under theSurvey of sub-surface cavities in the liquefied ground caused by the Great East Japan
Survey of sub-surface
cavities in the liquefied ground caused by the Great East Japan Earthquake
Earthquake

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Vietnampavement from migrating upwards because of the liquefaction. Furthermore,cavities found in cement stabilized locations (the cement stabilization isrecognized to have the highest bearing strength) are larger than those in the caseof the other two subbase materials, and the observed value shows there was no
upward migration of cavities.
2.7 Cavity survey in a non-liquefied area
2.7.1 Outline of the survey
About two years after the Earthquake, a cavity inspection survey was conducted in
Motomachi area of Urayasu-city where there was no liquefaction damage found,even though the area was located adjacent to where liquefaction damage occurred.
The survey was conducted for the purpose of comparison of the site conditions
and covered a distance of 10km. The survey revealed the possible existence ofcavities in 17 locations. An open-cut inspection was conducted at one of the sites(a shallow cavity close to a manhole) to confirm the conditions of the cavity,
followed by a penetration resistance test to measure the looseness of the soil on
the cavity bottom.
2.7.2 Analysis result
Through a borehole inspection, a cavity was ascertained at the shallow depth of
0.14m in the crushed rock layer immediately under the pavement. The area of thecavity was 1.19m2, the thickness was 0.34m, and the soil on the bottom was loose.
The site inspection revealed a rain water drain, a trace of chemical grouting in theside wall of a sewer manhole, and noticeable loosening of the soil on the cavity
bottom. The loose soil continued near as deep as the installed position of thesewer pipe. From these results, it is presumed that there could be one or moreholes in the sewer pipe joints, and soil washed away these holes caused a cavity toform and loosened the soil on the cavity bottom. (Fig. 12)
Plane view of open-cut site

Picture of open-cut site

W=0.7m
L=1.7mCavityCavity immediately
under asphalt

Thickness0.34m

Fig. 12 Result of open-cut inspection

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2.8 Follow-up inspection of liquefaction cavities repaired using grout
injection
2.8.1 Outline of inspection
The follow-up inspection was conducted using a borehole inspection in thoselocations of Narashino-city where liquefaction cavities were repaired using grout
injection. The inspection was conducted in four locations; about one year after the
grout injection took place. The grout material used was two-component fastcuring cement.
2.8.2 Inspection of grouted cavities and their surroundings
No changes to the road condition, such as subsidence were noticed, and no newcavities were found. It was confirmed that there were no gaps or voids under the
pavement. Only in No. 4 location, loose soil up to 0.34m in thickness was foundin the sand layer at the cavity bottom, but the position of the grout material was
confirmed to be at the same depth as the original cavity. Table 4 shows thecomparison between borehole pictures taken before the grout injection and thosetaken one year later.
Table 4: Internal conditions of cavities repaired by grouting
No.1

Borehole pictures
Left: Before grouting
Right: 1year after
grouting

SurveyResults

Groutmaterial
Bottom ofcavityNo.2

Before 1year later

Asphalt
Slag

Asphalt
Slag

CavityNo.3

Before 1year later
CavityBefore 1year later
CavityGroutmaterial
Sand

Grout
material
Sand

AsphaltGroutmaterial
Crushedrock

No.4
Before 1year later
Asphalt
Slag

CavityGroutmaterial

Loose
sand

Filling (No gap or void)
No loosening

Loosening
thickness:0.34m

2.8.3 Core sample study of grout materialCore samples show that the grout material was solidified in layers and there were
unevenly colored layers, presumably because of unsatisfactory mixing of cement
and curing agent (Fig. 13). A needle penetration test was used to measure uniaxial
compressive strength under different condition: moistened, dry, and saturated(cured). It was ascertained that there was no problem in terms of compressive
strength even though water is included. Through density measurements it wasdetermined that there was no shrinkage or age related deterioration (Table 5 ).
Cement (Gray)

Curing agent (White)

Fig. 13: No. 1 Core Sample
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Table 5: Uniaxial compressive strength and density measurements

qumin
quavg
2*
379kN/m
24,143kN/m2(cured state in
3,384kN/m2(dry state)water)
0.6-1.5g/cm3 (equivalent to the result of proportioning test of
Density
1.2g/cm3 )Note:* Even at qumin, the compressive strength is 3 times as high corresponding to CBR=6.
Uniaxial
compressive
strengthqumax

The core samples were broken easily by applying high pressure washing of
7.5MPa for about a minute. This indicates that there would be no difficulty incarrying out excavation in case repair is needed in the future. It was also
confirmed that even in the unlikely case of grout material leaking into pipelines, itwould be easy to remove the leaked grout material using high pressure washing.
2.9 Presumed mechanism of liquefaction cavity formation
The mechanism of liquefaction cavity formation is presumed to follow the process
shown in Fig. 14. The process was deduced based on the field observation of theliquefaction cavities and analysis of cavity interiors as reported in this study, in
addition to information from Kuwano’s model tests5) simulating the formation ofliquefaction cavities.
Good pavement

Liquefaction

Sand boilingpavement joints, etc.

Continued sandboiling

End of sand boiling(formation of a cavity)

Asphalt
Road subbase

Loosened
subgrade

Road subgrade
Groundwater

Groundwater

Groundwater

Fig. 14: Presumed mechanism of liquefaction cavity formation
3. PREVENTION OF SUBSIDENCE CAUSED BY LIQUEFACTIONCAVITIES
Fig. 15 describes the knowledge obtained in the present study as to how thedegree of safety (risk of subsidence or cave-ins) of roads relates to the progress ofcavity formation under the road surface.

Fig. 15: Relation between the safety of the road and occurrence of subsurface
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It is necessary to consider proactive measures to prevent subsidence due toliquefaction cavities in two distinctive cases: one for normal times and the otherimmediately after earthquake disasters. In normal times, the main targets are thosecavities which are yet to be repaired and cavities which were already repaired
using grout injection. At the same time attention has to be paid to detect thepossible spreading of loose soil around the cavities. Until cavities are repaired
properly, constant attention has to be maintained by regular patrols, etc. Presently
in Japan, the possible recurrence of large scale earthquakes is anticipated. It was
confirmed by this study that the groundwater level in those areas where cavities
formed still has not receded to less than GL-1m, and it is not expected that thiswill return to the previous safe level. Therefore, if a major earthquake occurs
again in those areas, the recurrence of liquefaction is unavoidable. Especiallyalong those arterial roads where strings of cavities were found, cavity inspection
surveys to assure the safety of the roads will have to be conducted urgently after
an earthquake before the start of emergency relief activities.
4. CONCLUSION
Research in this study focused on those cavities formed under the road surface
due to liquefaction on an unprecedented scale. Traditionally, the formation ofcavities under the roads is considered as one of the phenomena which occur
because of age related deterioration of underground infrastructure. Accordingly,
countermeasures were taken from the view point of maintenance and repair ofroad infrastructure. The liquefaction cavities caused by the Great East Japan
Earthquake are clearly different from those cavities found during regular surveys.
The following summarizes the findings of this study:
1. Liquefaction caused many cavities under the roads in a very short period oftime. Sewer lines damaged by the Earthquake also caused cavities, whose
formation spread out over a relatively longer period of more than a few months.
2. The cavity occurrence ratio in liquefied areas was 7 times larger than thenormal condition. Many of these cavities were thin, had large areas, and eroded
the road subbase leaving undulation at the cavity bottom.
3. Locations where many cavities formed coincided with large scale sand boiling,subsidence or cave-in of the road surface, and cavities were formed especiallyalong pavement joints, around manholes where there were gaps, and aroundburied sewer line structures.
It is hoped that this study will serve as a basis of a practical guide for roadadministrators who have to carry out emergency countermeasures to prevent theformation of cavities under the similar situations when a large scale earthquake
strikes in the future. By that time, solutions for the following issues will certainly
be needed: standardized inspection surveys methods, selection of repair methods,
and countermeasures to suppress cavity formation. We hope from the bottom of
our heart that, in addition to this study, the precious experiences of many of those
involved and the fruits of effectively executed measures will be systematicallycompiled to act as a road map.

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ACKNOWLEDGMENTS
This study was carried out with grants provided by the project of The Japanese
Geotechnical Society for investigation aimed at the improvement of geotechnicalengineering for road management. Details are found in relevant reports listed in
the References. Koto-ward of Tokyo, Urayasu-city, Chiba Pref., andNarashino-city, Chiba Pref., responded wholeheartedly.
REFERENCES
1) The Japanese Geotechnical Society., 2012. Issues and Countermeasures ofFoundation Disaster at the Time of Earthquake (Secondary) - Lessons Learned
and Recommendations from The Great East Japan Earthquake 2011, Page 119.
(in Japanese)
2) The Ministry of Land, Infrastructure and Transport, Kanto Regional
Development Bureau & The Japanese Geotechnical Society., 2011. Report ofActual Conditions of Ground Liquefaction in the Kanto Region which due to the2011 off the Pacific coast of Tohoku Earthquake, Page 103. (in Japanese)3) Tatsuhiko K, The Annual Technical Survey Report of Tokyo Bureau sewerage.,2012. About Countermeasures against Liquefaction in Shinkiba (Pipe Line)caused by The Great East Japan Earthquake., Page 65. (in Japanese)4) Yutaka K, Ryoko S., 2012. Study on the Occurrence of Liquefaction Cavities
under Roads (Part I): Characteristics of the Formation of Liquefaction Cavities,
47th Geotechnical Symposium, 1457-1458. (in Japanese)5）Reiko K., 2013. Model Tests Simulating Sub-surface Cavities Formed in the
Liquefied Ground, USMCA2013

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Model tests simulating sub-surface cavities
formed in the liquefied ground
Reiko KUWANO1, Jiro KUWANO2, Shinpei TAIRA3, Mari SATO4,
Ryoko SERA5 and Yutaka KOIKE5
1
Professor, ICUS, IIS, the University of Tokyo, Japankuwano@iis.u-tokyo.ac.jp
2
Professor, GRIS, Saitama University, Japan
3
Former student, Saitama University, Japan
4
Graduate student, IIS, the University of Tokyo, Japan
5
GEO SEARCH CO. LTD., Japan
ABSTRACT
Significant number of subsurface cavities was found in the liquefied ground after theGreat East Japan earthquake. Using the results of the radar exploration conducted in
Urayasu-city, Shinkiba-area and Narashino-city, all of those suffered from damage by
the ground liquefaction, characteristics of sub-surface cavities are investigated. It was
found that cavities tended to form near man-holes and joints in pavement. Size/shape ofthe cavities is larger and thinner compared to those of cavities observed in the nonliquefied ground.
A series of model tests was conducted in order to understand the mechanism ofunderground cavity formation when liquefaction occurs. Liquefaction and sand boiling
was simulated in the model test. Sand grains initially moved horizontally and thenvertically, causing disturbance and loosening in the ground. Gaps and voids near the
ground surface were eventually generated at the location of the boiled sand.
Penetration resistance of the model ground was measured after the test, indicating thatthe buried structure may have some effects on the extent of ground loosening around thestructure.
Keywords: subsurface cavity, liquefaction, boiled sand, ground loosening

1. INTRODUCTION
A ground penetration radar survey was conducted on the roads of Urayasu-city,
Shinkiba-area and Narashino-city, all of which suffered from damage caused by theground liquefaction during the Great East Japan Earthquake. A large amount of
fluidized sand, or sand boiling, was observed and a significant number of subsurface
cavities were found in the liquefied ground. Sera et al (2013) reported patterns of subsurface cavities observed in the disaster areas and characteristics of sub-surface cavities
obtained by the survey are analyzed. It was found that cavities had a tendency to form
near manholes and joints in the pavement. These cavities have a larger area, but are
thinner compared to cavities normally observed in non-liquefied ground.

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In this study, a series of model test was conducted to investigate the mechanism of subsurface cavity formation. Penetration resistance was also measured to evaluate theground loosening created around the cavities

2. TEST PROCEDURE
2.1 Apparatus
A model ground was prepared in a soil chamber of 30cm long, 8cm wide and 20cm high,as shown in Figure 1. Water was supplied from the bottom of the model ground.
Hydraulic gradient of the water supply could be adjusted by the elevatable water tankconnected to the bottom of the soil chamber. Surface of the model ground was coveredby an acrylic lid having 2mm wide openings, from those boiling sand could be erupted.
Water table was adjusted by the drainage at the side wall of the chamber.

Figure 1. Photo and schematic figure of apparatus
2.2 Model ground
Silica sand No.7 was used for the material of the model ground. It has mean diameter of
0.15mm. Maximum and minimum void ratios are 1.24 and 0.74 respectively. Loose

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sand ground,sand ground,
relative
relative
densitydensityof approximatelyof approximately
75%,75%,was prepared
was preparedby thebyair-pluviation.
the air-pluviation.
-3
cm/s.
cm/s.
ColoredColoredsand wassandputwasonputtheon theThe permeability
The permeabilityof theofgroundthe ground
was around
was around
3.4 ×10
3.4 -3×10
surfacesurfaceand inandfront
in frontof theofground,
the ground,as shown
as shown
in Figurein Figure2, for2,theforobservation
the observationof sandof sandgrains’grains’movement.
movement.

FigureFigure2. Set-up
2. Set-up
of modelof modelgroundground

2.3 Test
2.3 procedure
Test procedure
WaterWater
was slowly
was slowly
penetrated
penetrated
and theandmodelthe model
groundgroundwas saturated
was saturated
in advance.
in advance.
Then Thenthe thewaterwatertank wastank elevated
was elevated
to apply
to apply
additional
additional
hydraulichydraulicgradient
gradient
to generate
to generateliquefactionliquefactionin theinground.
the ground.
Sand Sand
grainsgrains
lost effective
lost effective
stressesstressesand upward
and upward
seepageseepageflow flowcausedcausedsand sandboilingboilingfrom fromthe opening
the opening
in theinlid.
the After
lid. Afterthe test,
the water
test, waterin theinmodel
the model
groundgroundwas wasdraineddrainedfor morefor morethan than
24 hours
24 hours
and penetrationand penetration
resistanceresistance
was measured
was measured
at five
at fivelocationslocationsusingusing
a 3mm
a 3mm
diameterdiameterneedle.
needle.
In total,
In total,
six tests
six tests
were wereconducted
conducted
as shown
as shown
in inTableTable
1. 1.
TableTable
1: Test
1: condition
Test conditionand sandand boilingsand boilingphenomena
phenomena
observed
observed
Case Case
Opening
Opening Buried
Buriedstructure
structure Water
Water
Water
Water
head headdifference
difference
No. No.(x: cm)(x: cm)tabletable
Shape,
Shape,
size size
Location
Locationwhenwhenverticalvertical(z: cm)(z: cm) at theat the(x, z)(x, z)
beginning
beginningof of movement
movementof sandof sandsand sandboilingboilinggrains
grainswas identified
was identified0
0 x=0 x=0
Not observed
Not observed- z=-1.5z=-1.5 60cm60cm

Model
tests
sub-surface
cavities
formedin thetheinliquefiedgroundModelModeltests simulating
simulating
tests simulating
sub-surface
sub-surface
cavities
cavities
formedformedinliquefiedthe liquefied
groundground395

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1

2

3

4

5

1 x=0 x=0

-

-

-

-

z=0 z=030cm30cm

90cm90cm

35cm35cm

Not observed
Not observed

30cm30cm

70cm70cm

30cm30cm

110cm
110cm

55cm55cm

Not observed
Not observed

Rectangular(-1, -5)(-1, -5) z=0 z=0
2 x=0 x=0 Rectangular2×10cm2×10cm3 x=0 x=0 Pipe φ6cm
Pipe φ6cm (0,-9)(0,-9) z=0 z=0

4 x=0 x=0 Pipe φ6cm
Pipe φ6cm (9,-9)(9,-9) z=0 z=05x=±7.5
Pipe φ6cm (0,-9)(0,-9) z=0 z=0
x=±7.5Pipe φ6cm

3. TEST
3. TESTRESULTSRESULTS
2.1 Sand
2.1 Sandboilingboiling
Sand Sandboilingboiling
was observed
was observedin allinthealltest
thecases.
test cases.
HydraulicHydraulicgradient
gradient
at theatbeginningthe beginningof ofboiling,boiling,
and atandtheatmoment
the moment
whenwhenverticalverticalmovement
movementof sandof sandparticles
particles
was identified
was identified
is isshownshownin Tablein Table
1. Although
1. Although
the drain
the drainlines lines
were werelocatedlocatedat or atbelow
or below
the surface,
the surface,
the thedrainagedrainage
couldcould
not keepnot keepup withup withthe supply
the supplyof water.
of water.
Therefore
Therefore
the water
the water
table table
at theat the
beginning
beginningof sandof sandboilingboiling
camecame
to be toabove
be abovethe groundthe groundsurface.
surface.
WhenWhen
the water
the water
head headdifference
difference
becamebecamelargerlarger
than 30cm,
than 30cm,
sand sandboilingboiling
startedstartedin casesin cases
1 to 4.
1 toConsidering
4. Consideringthat thethat heightthe heightof theof model
the model
groundgroundwas 20cm,
was 20cm,
hydraulichydraulicgradient
gradientwas 1.5,
was which
1.5, which
exceededexceeded
criticalcriticalhydraulichydraulicgradient.
gradient.
In caseIn 1,
case
the1,flow
the rate
flowofratewaterof waterat theatopening
the opening
was wasmeasuredmeasured
to beto0.75cm/s,
be 0.75cm/s,
whichwhichapproximately
approximately
coincided
coincidedwith withthe value
the valueof flowof flow
rate rate
calculated
calculatedby thebyassumption
the assumptionof uniformof uniform
waterwater
seepageseepagefrom frombottom.
bottom.

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After for a while from the beginning of sand boiling, it was observed that sand grains
moved horizontally toward the opening in the gap between the lid and ground surface asshown in Figure 3. Further increasing hydraulic gradient caused vertical movement ofsand grains. Especially when buried structure or pipe was located near the opening,water flow path seemed to concentrate around the buried structure, which often caused
ground disturbance and loosening, as shown in Figure 4. At the end of the test, thesurface of the ground became undulated as shown in Figure 5.

a) Case 1 (water head difference: 60cm)b) Case 2 (water head difference: 60cm)

Figure 3. Horizontal movement of sand particlesa) Case 3 (water head difference: 70cm)b) Case 3 (water head difference: 100cm)

Model Modeltests simulating
sub-surface
cavities
formedin theinliquefiedgroundtests simulating
sub-surface
cavities
formedthe liquefied
ground397

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Figure 5. Undulated surface of the ground after the test (Case 4)
2.2 Ground disturbance and loosening around cavities
Figures 6 to 10 show the results of penetration test conducted after test cases 0, 2, 3, 4
and 5. For case 0, as shown in Figure 6, penetration resistance at all the locations
showed similar results, indicating that the deep ground was not disturbed since themagnitude of sand boiling was small and only sand particles near the surface moved
horizontally. In case large scale sand boiling occurred, especially when buried structure
was located near the opening, there was significant reduction of penetration resistance.

Figure 6. Penetration resistance after the test (Case 0)398

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Figure 7. Penetration resistance after the test (Case 2)

Figure 8. Penetration resistance after the test (Case 3)

Figure 9. Penetration resistance after the test (Case 4)

Model Modeltests simulating
sub-surface
cavities
formedin theinliquefiedgroundtests simulating
sub-surface
cavities
formedthe liquefied
ground399

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3. CONCLUSIONSA series of model tests was conducted to simulate liquefied ground under the pavement
in order to investigate the effects of sand boiling on the formation of subsurface cavities.
Following conclusions were drawn from the study.
� Horizontal movement of sand grains was observed in the early stage of sand boiling.
When larger hydraulic gradient was applied, vertical movement of sand occurred.
� There was little disturbance in deep ground for the case of small scale sand boiling.
In large scale sand boiling, especially when the some buried structures exist, deep
ground may have loosening due to the disturbance cause by vertical sand movement
along the water flow paths.
� In general, sub-surface cavities due to sand boiling locate near the surface and thebottom of the cavity tends to undulate. This feature was also confirmed in the fieldsurvey.

ACKNOWLEDGEMENT
This study was carried out with grants provided by the project of The Japanese
Geotechnical Society for investigation aimed at the improvement of geotechnicalengineering for road management.

REFERENCES
Sera, R., Koike, Y., Nakamura, H., Kuwano, R. and Kuwano, J., 2013. Survey of subsurface cavities in the liquefied ground caused by the Great East Japan Earthquake,
Proc. 12th International symposium on new technologies for urban safety of mega cities
in Asia, USMCA, Hanoi Vietnam, October 2013.

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Climate change effects
in Chindwin River basin, Myanmar
Win Win ZIN1 and Khin Than YU2
Associate Professor, Civil Engineering Department,
Yangon Technological University, Myanmar
winwinzin@gmail.com
2
Pro-rector, Yangon Technological University, Myanmar
1

ABSTRACTThis paper examines the possible effects of climate change on hydrological andmeteorological variables in Chindwin river basin. These variables are important
indicators of climate change. Chindwin river has the catchment area of 115,300
km2. One of the commonly used tools for detecting changes in climatic andhydrologic time series is trend analysis. In this study, the Mann-Kendall nonparametric test, which is widely used to detect trends, was applied. The change
per unit time was estimated by applying Sen’s estimator of slope. Annual
maximum rainfall at Minkin displayed a significant increasing trend. The
application of a trend detection framework results in the identification of somesignificant trends in the annual minimum flow. Noteworthy was strong decreasing
trend in the annual minimum flow of Kalaewa and Monywa. A noticeable increasein the monthly mean temperature was observed mostly in Mawlaik, Kalaewa andMonywa. It is important to investigate present and probable future climaticchange patterns and their impacts on water resources so that appropriate
adaptation strategies may be implemented.
Keywords: climate change, trend analysis, non-parametric test, Mann-Kendall,
Sen’s slope
1. INTRODUCTION
River systems have been changed in the global context as a result of both natural
factors (climate change) and anthropogenic factors (land use change, river
regulations, and water abstraction etc.) (Walling and Fang, 2003). The availabilityof long-term records of hydrological data enables identifying the presence ofchanges in the river systems and deciphering the possible influencing factors ofthe detected changes. The detection of changes in the long-term time series ofhydrological data is of scientific and practical importance in the water resource
management and is regarded as a permanent exercise with the continuously
updated data (Kundzewicz, 2004).
Most water resources projects are designed and operated based on the historicalpattern of water availability, quality and demand, assuming constantly climatic
behaviour (Westmacott and Burn, 1997; Abdul Aziz and Burn, 2006).
Precipitation, streamflow and evapotranspiration are important variables in401

October
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Vietnamdiagnosing climate change as well as revealing the eco-environmental response to
climate change in regional scale. It is important to investigate present andprobable future climatic change patterns and their impacts on water resources sothat appropriate adaptation strategies may be implemented. Since thegeomorphologic evolution of watershed is quite slow in comparison with climatechange, the detectable changes in the hydrologic regimes of stable, unregulated
watersheds may be considered as the reflection of changes in climate.
Consequently hydrologic variables might be used as indicators to detect andmonitor climate change (Kahya,2004). Analysing different hydrological andmeteorological variables will indicate which variable is most affected by changes
in the climate. Burn and Soulis (1992) suggest having a wide range of hydrologic
variables to monitor since it is expected that climatic change will result in adiversity of environmental responses.
There are eleven different variables used in this study that are anticipated to beaffected by climate change. Trend detection will be conducted in the monthly,
seasonal and annual time series. The variables include the mean annual flow,mean monthly flow, extreme annual flow, mean seasonal flow, mean annual
rainfall, mean monthly rainfall, annual maximum rainfall, annual total rainfall,mean seasonal rainfall and mean monthly temperature. Annually extreme
variables, such as annual maximum and minimum values, are also to be examined.
This paper examines the possible effects of climate change on hydrological andmeteorological variables in Chindwin river basin. These variables are important
indicators of climate change. One of the commonly used tools for detectingchanges in climatic and hydrologic time series is trend analysis. In this study, theMann-Kendall non-parametric test, which is widely used to detect trends, wasapplied. The change per unit time was estimated by applying Sen’s estimator ofslope.
2. STUDY AREAThe Chindwin river is naturally configured with tremendous segments of rivulets,
streamlets and tributaries and it could of course be ranked as the largest tributaryof the Ayeyarwaddy river. The source of the entire river system approximately
falls at 97.00 degree Eastern longitude and 26.50 degree Northern latitude. The
basin is situated in North-West part of Myanmar and is covered with thick tropicalforest. The Chindwin river has the catchment area of 115,300 km2. The rivercourse between Hkamti and the confluence has a gentler slope of 1:11,000, on thecontrary, for the upstream of Hkamti with a steeper slope of 1:2300. There are
only six rain gauge stations and five discharge gauge stations within the basin.
Location of study area is shown in Figure 1.
Hydroclimatologists are concerned with analyzing time series by concentrating on
differences in 30-year normals along the whole period of records. This is why theperiod of 30-year is assumed to be long enough for a valid mean statistic. It alsoamounts to describing hydroclimatic time series as non-stationary with local
periods of stationary (Kite, 1991). Burn and Elnur (2002) stated that the selectionof stations in a climate change research is substantial at the initial step and that a402

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minimum record length of 25 years ensures validity of the trend results
statistically.
The length of data set in this study, mostly 46 years, suffices the minimum
required length in searching evidence of climatic change in hydroclimatic timeseries. The majority of rainfall and streamflow records include observations of 46
years spanning from 1967 to 2012. The basin covers annual total rainfall from 760
mm in the south to about 3820 mm in the north. The majority of temperaturerecords include observations of 38 years spanning from 1975 to 2012. Annual
average temperature of basin is 25.7 C. Land use types in the basin are closed
forest, degraded forest, agricultural land, open land and water. The dominant land
use type in the basin is closed forest. According to some researchers’ results, it isseen that land use changes in the river basin.

Figure 1: Location map of Chindwin river basin
Climate change
effects
in Chindwin
Riverbasin, river
Myanmar
Climatechangeeffects in
Chindwinbasin, Myanmar403

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Hanoi,Hanoi,
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Vietnam

3. METHODOLOGY
The detection of trends in measured time series data can be posed as a hypothesis
testing problem in which the null hypothesis (Ho) is that there is no trend in thedata, and the alternate hypothesis (H1) is that there is a trend in the data. A numberof parametric and non-parametric tests have been applied for trend detected. There
are trend detection tests such as Mann-Kendall test, Spearman’s Rho test, Sen’s T
test and linear regression test. One of the widely used in non-parametric tests for
detecting trends in the time series is the Mann-Kendall test. In this study MannKendall test was applied.
3.1 Serial correlation
The presence of serial correlation can complicate the identification of trends inthat a positive serial correlation can increase the expected number of false positive
outcomes for the Mann-Kendall test (von Storch and Navarra,1995). Several
approaches have been suggested for removing the serial correlation from a data
set prior to applying a trend test. The two common approaches are to pre-whiten
the series or to ‘prune’ the data set to form a subset of observations that are
sufficiently separated temporally to reduce the serial correlation.
The pre-whitening approach is adopted herein and involves calculating theserial correlation and removing the correlation if the calculated serial correlation
is significant at 5% level. The pre-whitening is accomplished throughypt = yt+1 - r yt

(1)

where ypt is the pre-whitened series value for time interval t, yt is the original timeseries value for time interval t, and r is the estimated serial correlation coefficient.
3.2 Mann–Kendall test
The Mann–Kendall (MK) statistical test (Mann,1945; Kendall,1975) is a nonparametric approach for the monotonic trend. It has been widely used to assess thesignificance of trends in hydro-meteorological time series due to its robustness
against nonnormally distributed, censored and missing data as well as its
comparable power as parametric competitors (Helsel and Hirsch, 1992; Serrano etal., 1999; Yue et al., 2002).
This test has been widely used to test for randomness against trend in hydrology
and climatology. It is a rank-based procedure, which is robust to the influence of
extremes and good for use with skewed variables. According to this test, the null
hypothesis H0 states that the deseasonalized data (x1, . . ., xn) is a sample of n
independent and identically distributed random variables. The alternative
hypothesis H1 of a two-sided test is that the distributions of xk and xj are not
identical for all k, j  n with k  j. The test statistic S, which has mean zero and avariance computed by Equation (4), is calculated using Equations (2) and (3), andis asymptotically normal (Hirsch and Slack, 1984):������������������������������������������������� � ∑������ ∑����� ������ � �� �

404

(2)

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ICUS Report 73������(�� − �� ) > 0��������������������������������������(�� − �� ) = � 0�����(�� − �� ) = 0 �−�����(�� − �� ) < 0����������������(�) = ��(� − �)(�� � �) − ∑� �(� − �)(�� � �)����

(3)
(4)

The notation t is the extent of any given tie and t denotes the summation over all
ties. In cases where the sample size n > 10, the standard normal variate z iscomputed by using Equation (5) (Douglas et al., 2000).
��������(�) ������ > 0������������������������������������������������������� = 0��������������� = 0� ����������(�) ����� < 0 �
�
�

(5)

In a two-sided test for trend, H0 should thus be accepted if z  z /2 at the  levelof significance. A positive value of S indicates an ‘upward trend’; likewise, anegative value of S indicates ‘downward trend’. The significance level thatindicates the trend’s strength.
3.3 Sen’s estimator
If a linear trend is present in a time series, then the true slope (change per unittime) can be estimated by using a simple non-parametric procedure developed by
Sen (1968b). The slope estimates of N pairs of data are first computed by��������������������������������������������� =(�� ��� )(���)for i = 1,……,N(6)

where xj and xk are data values at times j and k (j > k) respectively. The median ofthese N values of Qi is Sen’s estimator of slope. If N is odd, then Sen’s estimatoris computed by Qmedian= Q(N+1)/2 and if N is even, then Sen’s estimator is computedby������������������������������������������������������������ =���� ��(���) �
�

�

��

(7)

The detected value of Qmedian is tested by a two-sided test at the 100(1 -)%confidence interval and the true slope may be obtained by the non-parametric test.
4. RESULTS AND DISCUSSION
4.1 Streamflow
It is seen that some significant negative trends in annual minimum streamflow.
The largest negative trend was occurred in Kalaewa. There are no significant

Climate change effects in Chindwin river basin, Myanmar
Climate change effects in Chindwin River basin, Myanmar405

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamtrends detected in the annual maximum streamflow and annual average
streamflow series. The mean monthly flow represents a further breakdown ofmean annual flow analysis. Stations located in southern part of basin such as
Kalaewa and Monywa display negative trends in monthly mean streamflow.
Homalin located in northern part of basin displays positive trends, suggesting
increase in monthly mean streamflow. In contrast, Hkamti and Mawlaik, ingeneral, show no trends.
It is seen that monthly mean streamflow in Monywa for most months decreased,with the strongest decrease in summer and winter. The results of Mann-Kendall
test with Sen’s slope estimator for discharge time series of Homalin, Kalaewa andMonywa are summerised in Table 1, Table 2 and Table 3 respectively. In thisstudy, the tested significance level  are 0.05,0.01 and 0.001.Figure 2 shows theresults for the annual minimum daily flow for study period.
Table 1: Results of Mann-Kendall test with Sen’s slope estimator for discharge
time series for HomalinTime series(m3/s)
Annual time series
Mean
Maximum
MinimumMonthly time series
January
February
March
April
May
June
July
AugustSeptember
OctoberNovember
December
Seasonal time series
Summer-season
Rainy-season
Winter -season

Mann-Kendall test
z

trend

significa
nce

3.0

+

2.4
2.1
2.1
1.9
2.3
0.2
1.2
2.1

+
+
+
+
+
+
+
+







3.0
2.0

+
+

**

**



*

Sen’s slope
estimator
Q
Qlowe Qupp
r

er

-3.72
-38.60
4.95

1.87

11.5
29.6
8.32

4.59
4.47
5.04
4.84
8.66
-11.79-9.27-30.54-16.83
5.76
4.99
4.75

0.94
0.37
0.26
0.02
1.00
-2.44
0.63

8.42
8.38
9.02
10.1
16.3
28.7
66.9
25.7
31.0
39.9
12.3
8.67

7.09
-13.03
4.83

2.73
0.23

11.5
17.0
8.64

Data series with significant trends are shown in bold. Qlower and Qupper are slope
confidence limits at the 95% confidence level.
* = 0.05 level of significance**  = 0.01 level of significance406

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ICUS Report 73***  = 0.001 level of significance
Table 2: Results of Mann-Kendall test with Sen’s slope estimator for discharge
time series for Kalaewa
Time series(m3/s)
Annual time series
Mean
Maximum
MinimumMonthly time series
January
February
March
April
May
June
July
AugustSeptember
OctoberNovember
December
Seasonal time series
Summer-season
Rainy-season
Winter -season

Mann-Kendall test
z

trend

0.0
-

+
-

0.0
0.2
0.5
0.7
0.7
-

+
+
+
+
+
-

0.1
-

+
-

significa
nce

***
*
***
**
*

Sen’s slope
estimator
Q
Qlowe Qupp
r

er

0.58
-70.00
-4.43

14.8
23.1
-6.00 -2.67

-2.80
-3.24
-3.21
-3.67
0.26
-1.27
12.79
-25.53
13.47
21.54
3.84
-2.94

-5.54
-5.16
-5.59
-6.97
-8.50
-7.38

-0.15
-1.43
-1.17
-0.83
10.7
43.7
93.8
35.8
69.1
64.4
18.8
1.46

-1.14
3.62
-0.91

-5.06
-6.52

3.09
38.4
3.28

Table 3: Results of Mann-Kendall test with Sen’s slope estimator for discharge
time series for Monywa
Time series(m3/s)
Annual time series
Mean
Maximum
MinimumMonthly time series
January
February
March
April

Mann-Kendall test
z

trend

-

-

-

-

significa
nce

**
**
**
*

Climate change
effects
in Chindwin
Riverbasin, river
Myanmar
Climatechangeeffects in
Chindwinbasin, Myanmar

Sen’s slope
estimator
Q
Qlowe Qupp
r

er

-9.21
-5.81
-4.73

6.29
103.
-7.57 -1.22

-6.62
-5.25
-3.13
-4.47

-3.52
-8.74 -1.86-6.90 0.31
-8.92 -0.06407

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May
June
July
AugustSeptember
OctoberNovember
December
Seasonal time series
Summer-season
Rainy-season
Winter -season

0.3
-

+
-

-

-

***

-2.33
-23.2310.01-28.86-9.54-26.06-13.56
-9.10

**

-3.13
-4.63
-10.73

-

7.48
29.3
76.1
20.9
45.5
36.1
1.67
-3.96

-9.15 2.33
27.3
-4.42

Figure 2: Trend results for annual minimum flow for the study period408

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4.2 Rainfall
Rainy season rainfall (from June to middle of October) accounted for about 85%
of annual rainfall. The rainfall stations in Chindwin river basin displayed
insignificant trends for annual total rainfall and annual average rainfall. Minkinstation indicated increasing trend in annual maximum rainfall. There are no
significant trends in most of the monthly rainfall time series in Hkamti, Homalin,
Mawlaik, Kalaewa and Monywa. It is seen that some significant positive trends inmonthly rainfall in Minkin.
4.3 Temperature
Geographically, the increasing trends of monthly mean temperature wereconcentrated in the southern regions of the river basin while the decreasing trends
monthly mean temperature appeared primarily in the northern regions of the river
basin.
5. CONCLUSION
The results of Mann-Kendall test showed some strong significant decreasing
trends in the annual minimum flow. The application of trend detection techniqueto Chindwin river basin has resulted in the identification of significant trends ofappearing in the southern parts of the river basin. The direction of trends ofmonthly flow is, in general, downward. The decrease in annual mean flow plays adominant role in the determination of reservoir capacity and the reservoir
management works afterward.
A noticeable increase in the monthly mean temperature was observed mostly in
Mawlaik, Kalaewa and Monywa. Noteworthy was strong decreasing trend in theannual minimum flow of Kalaewa and Monywa. The timing of a hydrologic event
was found to be influenced to the greatest extent by changes in temperature. The
hydrologic variables would have decreasing flow trends and negative correlations
with temperature.
It is important to investigate present and probable future climatic change patterns
and their impacts on water resources so that appropriate adaptation strategies may
be implemented. The trend attribution and the relation between the observed
streamflow trends and climate change should be addressed in future studies with
the inclusion of the influence of evapotranspiration variable. It may be concluded
the climate change has caused the downward trends in streamflow in lower partsof Chindwin river basin.
REFERENCES
Abdul Aziz, O.I., and Burn, D.H., 2006. Trends and variability in thehydrological regime of the Mackenzie River Basin. J. Hydrol. 319, 282–294.
Burn, H.B., and Elnur, M.A.H., 2002. Detection of hydrologic trends andvariability. Journal of Hydrology 255, 107–122.

Climate change
effects
in Chindwin
Riverbasin, river
Myanmar
Climatechangeeffects in
Chindwinbasin, Myanmar409

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Hanoi,Hanoi,
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VietnamBurn, D.H., and Soulis, E.D., 1992. The use of hydrologic variables in detecting
climatic change: possibilities for single station and regional analysis. In: Kite,
G.W., Harvey, K.D. (Eds.), Using hydrometric data to detect and monitor climaticchange, Proceedings of NHRI Workshop No. 8, National Hydrology ResearchInstitute, Saskatoon, Saskatchewan.
Douglas, E.M., Vogel, R.M., and Kroll, C.N., 2000. Trends in floods and low
flows in the United States: impact of spatial correlation. Journal of Hydrology
240, 90–105.
Helsel, D.R., and Hirsch, R.M., 1992. Statistical Methods in Water Resources.
Elsevier, Amsterdam.
Hirsch, R.M., and Slack, J.R., 1984. A nonparametric trend test for seasonal datawith serial dependence. Water Resources Research 20 (6), 727–732.
Kahya, E., and Kalayc, S., 2004.Trend analysis of streamflow in Turkey.Journalof Hydrology. 289,128-144.
Kendall, M.G., 1975. Rank Correlation Methods. Griffin, London, UK.
Kite, G., 1991. Looking for evidence of climatic change in hydrometeorologicaltime series. Western Snow Conference, April 12–15, Washington to Alaska.
Kundzewicz, Z.W., 2004. Searching for change in hydrological data.
Hydrological Sciences Journal 49, 3–6.
Liu, Q., Yang, Z.F., and Cui, B.S., 2008. Spatial and temporal variability ofannual precipitation during 1961–2006 in Yellow River Basin, China. J. Hydrol.
361, 330–338
Mann, H.B., 1945. Nonparametric tests against trend. Econometrica 13, 245–259.
Sen, P.K., 1968b. Estimates of the regression coefficient based on Kendall’s tau.
Journal of American Statistical Association 39, 1379–1389.
Serrano, A., Mateos, V.L., and Garcia, J.A., 1999. Trend analysis of monthly
precipitation over the iberian peninsula for the period 1921–1995. Physics andChemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere 24, 85–90.
Von Storch, H., and Navarra,A.,1995. Analysis of climate variability. Springer,
New York.
Walling, D.E., and Fang, D., 2003. Recent trends in the suspended sediment loadsof the world's rivers. Global and Planetary Change 39, 111–126.
Westmacott, J.R., and Burn, D.H., 1997. Climate change effects on the hydrologic
regime within the Churchill–Nelson River Basin. J. Hydrol. 202 (1), 263–279.

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Yue, S., Pilon, P., Phinney, B., and Cavadias, G., 2002. The influence ofautocorrelation on the ability to detect trend in hydrological series. Hydrological
Processes 16, 1807–1829.

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Seismic stability of reinforced soil wallsin the 2011 Tohoku Earthquake
Jiro KUWANO1, Yoshihisa MIYATA2 and Junichi KOSEKI3
1
Professor, GRIS, Saitama University, Japan
jkuwano@mail.saitama-u.ac.jp
2
Professor, Dept. of Civil and Environmental Eng., National Defense Academy,Japan
3
Professor, IIS, the University of Tokyo, Japan
ABSTRACTThe 2011 off the Pacific coast of Tohoku Earthquake of Mw=9.0 with a hugesource region of about 450km by 200km caused extensive damage of various
structures. This paper briefly reviews the reinforced soil walls in Japan first. After
discussing limit state levels of reinforced soil walls, the paper reports thesummary of seismic performances of about 1600 walls in the 2011 Tohoku
earthquake. It also reports some case histories on the reinforced soil walls whichwere subjected to the direct impact of the earthquake (shaking). Just less than 1%of the walls were seriously damaged but more than 90% of the walls did not show
any serious damage. Repair works of the damaged reinforced soil walls are
introduced as well.
Keywords: reinforced soil wall, limit state, damage statistics, repair works
1. INTRODUCTION
The 2011 off the Pacific coast of Tohoku
Earthquake (The 2011 Tohoku Earthquake) of
Mw=9.0 with a huge source region of about
450 km by 200 km occurred on March 11,2011 as shown in Figure 1 (USGS, 2012a). It
is the largest earthquake ever recorded inJapan and the fourth largest in the world after
1900 (USGS, 2012b). Seismic motions
observed in this earthquake are shown in
Figure 2 (Yamanaka, 2011). As comparedwith the 1995 Hyogoken-Nanbu (Kobe) andthe 2004 Chuetsu earthquakes, the 2011
earthquake has two main shocks withextremely long duration of vibration for morethan two minutes. Because of the huge source
region of the earthquake, the failure of thecrust (energy discharge) did not take place atonce but separately and gradually within thesource region. It caused extensive damage ofliquefaction in Tokyo and its surroundings. A

Figure 1: Source region and seismic
intensity （USGS, 2012a)

413

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamlot of failures of slopes and embankments occurred in Tohoku and Kanto regions.

Figure 2: Observed seismic motion during recent earthquakes
in Japan (Yamanaka, 2011)
Almost 20,000 people are dead or missing by the 2011 Tohoku earthquake.
Tsunami was the most serious impact of the earthquake. Inundation height andrun-up height were as high as about 40 m. It killed thousands of lives and caused
extensive damage of various structures such as seawalls and bridges. Many
seawalls and river dikes were washed out by the tsunami. However, many
reinforced soil walls survived the tsunami impact, though they were partly or fully
submerged.
There are numbers of reinforced soil walls in Tohoku region. Miyata (2012)
reported the damage of the walls by the earthquake and summarized that just lessthan 1% of the walls were seriously damaged (some walls were damaged by thetsunami) but more than 90% of the walls did not show any damage.
This paper briefly reviews the reinforced soil walls in Japan first, then reports thesummary of seismic performances of about 1600 walls in the 2011 Tohoku
earthquake. It also reports some case histories on the reinforced soil walls whichwere subjected to the direct impact of the earthquake (shaking) and repair works
for them.

Figure 3: Diffusion of reinforced soil wall technology in Japan (Ochiai, 2007)

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Basic

Advanced

Figure 4: Reinforced soil wall technology in Japan (modified Miyata, 2012)
2. REINFORCED SOIL WALLS IN JAPAN
Application of reinforced soil walls in Japan begun in the 1970s and increased
with time as shown in Figure 3 (Ochiai, 2007). Reinforced soil walls in Japan can
be classified into four types by the reinforcement, metal or geosynthetics, and thedevelopment phase, basic and advanced, as summarized in Figure 4 (modified
Miyata, 2012). They are a steel strip wall, a geosynthetic wall, a multi-anchor wall
(Fukuoka et al., 1980) and a geosynthetic wall with full-height rigid facing(Tatsuoka et al., 1989). The right-hand picture (Tatsuoka et al., 1996) in Figure 3
indicates the survived reinforced soil wall with full-height facing and the seriously
damaged adjacent houses in the 1995 Kobe earthquake (Great Hanshin
earthquake). The performances of reinforced soil walls proved their high seismic
resistance. Therefore, the application of this technology increased especially after
the 1995 Kobe earthquake (Koseki et al., 2006).

Figure Figure
5: Site 5:
investigationof earthquake
damagedamage
to reinforced
soil wallsoil
in theSite investigationof earthquake
to reinforcedwall2011 Tohoku
earthquake(Miyata,
2012)
in the 2011 Tohoku earthquake (Miyata, 2012)
Seismic stabilityof reinforced
walls in the
TohokuSeismic
Stability ofsoil
Reinforced
Soil2011
Walls
in the Earthquake2011 Tohoku Earthquake

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Table 1: Damage statistics of reinforced soil wall in the 2011 Tohoku earthquake(Miyata, 2012)
Steel strip walls

Geogrid walls

Multi-anchor walls

Ultimate limit state

0.3%

0.7%

0%

Restorability limit state

1.0%

4.3%

0%

Serviceability limit state

7.0%

0.7%

3.0%

No damage

91.7%

94.3%

97.0%

3. PERFORMANCE OF REINFORCED SOIL WALLS IN THE 2011
TOHOKU EARTHQUAKEThe 2011 Tohoku Earthquake is the largest earthquake ever recorded in Japan andthe fourth largest in the world after 1900 (USGS, 2012b). Wide area in the
Tohoku and Kanto regions were strongly shaken by the earthquake as shown in
Figure 1 (USGS, 2012a). At some locations, very high accelerations of more than
1000 gal, or even more than 2000 gal at particular sites, were recorded. Largesettlement, sliding failure, and collapsing of conventional type retaining wall of
unreinforced soil structure, such as road and railway embankments, earth dams
and housing sites, occurred by the earthquake.
With respect to the performances of reinforced soil walls, various teams went to
the wall sites, where the JMA (Japan Meteorological Agency) seismic intensity
scales were mostly greater than 5 upper. Although the current JMA scale is hard
to be converted to the MMI (Modified Mercalli intensity) scale, the former JMA
scale, IJMA, was roughly connected with the MMA scale, IMM, through theequation of IMM=0.5+1.5IJMA. If the sinusoidal seismic motion with a period of 1
second continues for a few seconds, IJMA of 5 upper corresponds to about 100 gal.
For IJMA of 7, about 600 gal is necessary for a period of 1 second, however about
2700 gal for a period of 0.1 second (JMA, 2012). Figure 5 shows the number ofinvestigated reinforced soil walls by prefecture in the Tohoku region for three
types of walls, i.e. steel strip walls (Terre Armee), multi-anchor walls and geogrid
walls.
The damage of reinforced soil walls can be classified into four levels, namely,
ultimate limit state, restorability limit state, serviceability limit state, and nodamage. Table 1 summarizes the damage statistics of investigated reinforced soil
walls in the 2011 Tohoku earthquake. The ultimate limit state is only less than 1%of investigated walls for all the three types. More than 90% of the walls show nodamage. It is to be mentioned that the 2011 Tohoku earthquake was so huge, andits aftershocks were also very strong. Such a strong seismic load was notconsidered in the design of reinforced soil walls. However, most of the walls

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showedshowedvery very
high highseismic
seismic
resistanceresistancein theinearthquake.
the earthquake.
This Thisimplies
impliesthat thethatactual
the actual
seismic
performanceof reinforced
soil walls
is considerably
higherseismic
performanceof reinforced
soil walls
is considerably
higherthan than
the thedesigntarget.
designtarget.

Case Case
1: Ultimate
1: Ultimate
limit limit
state stateof a geogrid
of a geogrid
wall wallCase Case
2: Ultimate
2: Ultimate
limit limit
state stateof a steel
of a steel
strip strip
wall wall

Case Case
3: Restorability
3: Restorability
limit limit
state state

Case Case
4: Serviceability
4: Serviceability
limit limit
state stateof a geogrid
of a geogrid
wall wall

Case Case
5: Serviceability
5: Serviceability
limit limit
state stateof a wallof a withwall withconcreteconcretefacingfacing
panelspanelsSeismicSeismic
stabilityof reinforced
walls
in Walls
theTohokuSeismic
Stability
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Case 6: collapsed embankment (left) and geogrid wall with no damage (right)
Figure 6: Performance of reinforced soil walls to the direct impact of seismic
motion (Cases1: Kaneko and Kumagai, 2011; 2: courtesy of Dr. Otani, 3 to 6:
JC-IGS Technical Committee)
4. PERFORMANCE OF REINFORCED SOIL WALLS TO THE DIRECTIMPACT OF SEISMIC MOTION
Some case studies of different level seismic performance of reinforced soil walls
shown in Figure 6 are introduced in the followings.
4.1 Case 1: Ultimate limit state of a geogrid wall
A 5 m high geogrid reinforced wall with expanded metal mesh facing collapsed.
Not only internal slippage but also connection failure was observed. This damage
state can be classified into the “ultimate limit state.” The estimated seismic
intensity was 6 lower at this location. The equivalent ground acceleration was
estimated to be 300 gal. The site investigation indicated that this collapse wascaused by the fact that the ground water level in this wall was very high becauseof the lack of a drainage system.
4.2 Case 2: Ultimate limit state of a steel strip wall
A 10 m high steel strip wall on the soft soil ground collapsed owing to the 7 mhorizontal sliding of the foundation slope caused by seismic motion. The
estimated JMS seismic intensity was 6 lower at this site. The equivalent groundacceleration estimated for the period of 0.5 sec was about 300 gal. The site
investigation revealed that this slope failure occurred because the foundation soil
was not sufficiently treated. Adequate ground improvement should have been
carried out.
4.3 Case 3: Restorability limit state of a geogrid wall
A 5.4 m high geogrid reinforced wall with wire mesh facing was damaged. A
considerable amount of horizontal deformation of the facing and a gap between
the reinforced soil wall and the rigid reinforced concrete structure were observed.

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This damage can be classified into the “restorability limit state” damage because
the horizontal deformation was more than the allowable limit. The estimatedseismic intensity was 6 lower at this location. The equivalent ground acceleration
was estimated to be 300 gal. Further, the site investigation revealed that thisdamage could be attributed to the fact that the fill material had a considerable
amount of fine contents and the ground water level in the wall was very high.
4.4 Case 4: Serviceability limit state of a geogrid wall
Although a gap between the geogrid reinforced soil wall and the concrete bridge
abutment was found similar to the Case 3, the horizontal facing deformation waswithin the allowable limit and the damage of the wall was ranked as the“serviceability limit state”. This wall was repaired using soil nailing, soil cement,
and vegetation technique, as shown in Figure 7.
4.5 Case 5: Serviceability limit state of a wall with concrete facing panels
A steel strip wall and a multi-anchor wall have concrete panel facing. After theearthquake, damage of the concrete panels was found at some points. This damage
is categorized as the “serviceability limit state.” A repairing method for thedamaged concrete panel has already been developed as shown in Figure 8. Only
the damaged part in the panel was cut, and concrete milk was injected into the
spot. Whole the panel can be replaced as well.

Figure 7: Repairing of differential deformation between geogrid reinforced walland RC structure

Figure 8: Repairing of concrete panel facing of steel-reinforced soil wall

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4.6 Case 6: No damage of a geogrid wall
A 5.4 m high geogrid reinforced wall with wire mesh facing was found to have nodamage. This wall was constructed as a repair work of housing embankment
failed due to heavy rain. However, an ordinary embankment without
reinforcement failed due to the seismic motion in the slope beside the reinforced
wall as seen in the figure. At this site, a strong seismic motion having the JMA
seismic intensity of 6 lower seemed to act on both the structures. This is the casehistory which clearly indicates the high seismic resistance of a reinforced soil wall
5. SUMMARY
The 2011 off the Pacific coast of Tohoku Earthquake of Mw=9.0 caused extensive
damage of various structures. Damage caused by tsunami was tremendous and a
lot of lives were lost. Performance of reinforced soil walls in the 2011 Tohoku
earthquake was reported in this paper. It was found through approximately 1600
site investigations that reinforced soil walls showed very high seismic resistancein the 2011 Tohoku earthquake. Just less than 1% of the walls were seriously
damaged but more than 90% of the walls did not show any damage. Repair worksof the damaged reinforced soil walls were introduced as well.
REFERENCES
Fukuoka, M., Imamura, Y., Kudoh, K., Naitoh, S. and Fukahori, T., 1980.
Research on multi-anchor wall, Proceedings of 15th Japanese GeotechnicalSociety Annual Meeting, Hiroshima, Japan, 1525-1528 (in Japanese).
Japan Meteorological Agency, 2012. Seismic intensity and acceleration.
http://www.seisvol. kishou.go.jp/eq/kyoshin/kaisetsu/comp.htm, viewed on
September 11, 2012 (in Japanese).
Kaneko, K. and Kumagai, K., 2011. Damages of reinforced earth walls at Iwate
area in the 2011 off the Pacific coast of Tohoku Earthquake and tsunami,
Geosynthetics Technical Information, JC-IGS, 27 (2), 16-23 (in Japanese).
Koseki, J., Bathurst, R.J., Guler, E., Kuwano, J. and Maugeri, M., 2006. Seismic
stability of reinforced soil walls, Proceedings of the 8th International Conference
on Geosynthetics, Yokohama, Japan, 1, 51-77
Miyata, Y., 2012. Reinforced soil walls during recent earthquakes in Japan andgeo-risk-based design. Keynote Lecture, Second International Conference on
Performance-Based Design in Earthquake Geotechnical Engineering, May 28-30,
2012, Taormina, Italy, draft.
Ochiai, H., 2007. Earth reinforcement technique a role of new geotechnicalsolutions - memory of IS Kyushu, Proceedings of the International Symposium on
Earth Reinforcement, IS-Kyushu 2007, Fukuoka, Japan, 1–23.
Tatsuoka, F. Tateyama, M. and Murata, O., 1989. Earth retaining wall with a shortgeotextile and a rigid facing, Proceedings of the 12th ICSMFE, Rio de Janeiro, 2,1311-1314.
Tatsuoka, F., Tateyama, M. and Koseki, J., 1996. Performance of soil retaining
walls for railway embankments, Soils and Foundations, Special Issue for the 1995

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Hyogoken–Nambu Earthquake, 311-324.
US Geological Survey, 2012a. Magnitude 9.0 - Near the east coast of Honshu,
Japan,
http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0001xgp/,
viewed on September 11, 2012.
US Geological Survey, 2012b. Magnitude 8 and Greater Earthquakes Since 1900,
http://earthquake.usgs.gov/earthquakes/eqarchives/year/mag8/magnitude8_1900_
mag.php, viewed on September 11, 2012.
Yamanaka, H., 2011. Strong motion characteristics and aftershock observations,Center for Urban Earthquake Engineering (CUEE), Tokyo Institute of Technology
Newsletter No.11 - 2011 Tohoku Pacific Earthquake.

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Ideal regional disaster management plan
based on the experience fromthe 2011 Great East Japan Earthquake
Kimiro MEGURO
Professor, Director, ICUS, IIS, The University of Tokyo, Japanmeguro@iis.u-tokyo.ac.jp

ABSTRACTAt 14:26 (Japan local time) on March 11, 2011, gigantic earthquake with Mw 9.0,
called Great East Japan Earthquake, occurred off the coast, approximately 70 km
east of Miyagi Prefecture, Japan. The earthquake triggered powerful tsunami
waves that reached heights of up to 40.5 m in Miyako City, Iwate Prefecture.
Approximately twenty-thousand people were killed mainly due to Tsunami andover 100 thousand houses and buildings were completely collapsed. The numberof municipalities in severely affected areas was over 240. In this paper, lessons
learned from the disaster due to the 2011 Great East Japan Earthquake and thesubsequent reconstruction process, issues and problems of the current regional
disaster management plan are examined and the ideal regional disastermanagement plan and its implementation strategy are introduced. A
comprehensive disaster management system is introduced based on three relief
types (self-help effort, mutual assistance, and public support) and seven stages ofdisaster countermeasures (damage mitigation, preparedness, prediction & early
warning, damage assessment, disaster response, recovery and reconstruction).
Also, specific action plan with appropriate priorities is proposed.
Keywords: disaster management plan, total disaster management, disaster life
cycle, self-help effort, mutual assistance, and public support
1. INTRODUCTION
In this paper, based on the lessons learned from the disaster and subsequent
reconstruction process from the 2011 Great East Japan Earthquake and Tsunami
disaster, issues and problems of the current regional disaster management plan are
examined. In order to reduce the damage anticipated from Tokyo metropolitan
earthquake and huge earthquakes along the Nankai Trough, the plan needs to berevised and the strategy for implementing ideal regional disaster management planand specific action plan with appropriate priorities are introduced.

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2. ISSUES OF THE REGIONAL DISASTER MANAGEMENT PLAN
2.1 Summary of regional disaster management plan
Within the legal system of the Disaster Countermeasures Basic Act enacted in1961 in the wake of the damage caused by the Ise Bay typhoon of 1959, theregional disaster management plan is formulated by the local governments basedon national basic disaster management plan prepared by the Central Disaster
Management Council. It is positioned at the top of legal system and comprises ofa comprehensive disaster management plan composed of damage estimation andplans for disaster prevention, response, recovery and reconstruction for each typeof disaster.
2.2 Issues of Disaster Countermeasures Basic Act
The regional disaster management plan is determined by the municipalities andprefectures based on the national basic disaster management plan specified in the
Disaster Countermeasures Basic Act, considering both social and naturalenvironment of the region. Disaster Countermeasures Basic Act which provides
the framework for regional disaster management plan specifies the policies andbasic disaster response measures. It is intended to adjust the overall system andpolicies of disaster management organizations. Due to the nature of disastermanagement which is in close contact with the residents, the authority of themayor of a municipality is enhanced. However, there are issues with thisapproach which have been pointed out for a long time and they were also
recognized during the 2011 Great East Japan Earthquake and Tsunami Disaster.
Five major issues pointed out are as follows:
1) Scale of disaster
Strengthening of disaster response plan in case of a large-scale disaster over awide area that exceeds the border between prefectures is needed.
2) Administrative coordination
Administrative coordination among the adjacent municipalities, especiallythose under different prefectures, is difficult.
3) Resident participation
The opportunity for the local residents and NPO/NGO staffs to participate in
the planning phase is extremely low and the activity for publicizing disasterrelated information is insufficient.
4) Principles in Disaster Relief Act or provision of public fund
The disaster related laws are applied based on the scale of disaster however it
is unfair considering at individual’s level.
5) Coordination among the responsible authorities
While the Disaster Relief Act is under the jurisdiction of a Ministry of Health,
Labor and Welfare, the Disaster Countermeasures Basic Act is under the
Cabinet Office. Cooperative work between these two ministries is required inorder to realize rapid and efficient disaster response.

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2.3 Problems of regional disaster management plan
Facing the devastation beyond expectation caused by the Tsunami during the2011 Great East Japan Earthquake, the administrative function of manymunicipalities has dropped drastically. Under such circumstances, could theexisting regional disaster management plan function properly? Many of theexisting plans do not reflect the natural and social environment that is unique tothe region and that the way it is described is too abstract to follow at the time ofdisaster. The main problems are summarized into the following five points:
1) The request of help must come from the disaster affected municipalities toprefectures or adjacent municipalities during the large-scale disaster and thecountermeasures for regional coordination including the national government isinsufficient.
2) The current plan focuses on post-disaster countermeasures rather than on predisaster ones with an assumption that the work environment of the municipal
officers is safe and unaffected by the disaster. It is necessary to prepare
Business Continuity Plan based on the worst-case scenario.
3) There is a lack of regional cooperation and countermeasures involving the local
actors including residents based on the idea of “total disaster management” and“public support, mutual assistance and self-help effort”.
4) There is a lack of understanding for a proper disaster management based on thedisaster life cycle.
5) The countermeasures for recovery and reconstruction are poor.
In order to minimize the impact by the future big disaster, the problems describedabove must be solved and through reexamination of regional disaster management
plan is the most urgent issue.
2.4 Problems with municipalities
What are the problems municipalities would face when formulating the regional
disaster management plan? According to the surveys conducted to the prefecturesand municipalities along the coast of Pacific Ocean along the Nankai Trough in
February 2012, many of them have started to reexamine the regional disastermanagement plan and are recognizing the difficulty such as lack of man-power
especially staff with special knowledge and skills in disaster management, andlack in budget, etc.
3. IDEAL REGIONAL DISASTER MANAGEMENT PLAN
AND ITS IMPLEMENTATION STRATEGY
3.1 Vision for ideal regional disaster management plan
Based on the problems and issues discussed so far, the vision for ideal regional
disaster management plan is stated below. This is aimed at the entire frameworkof the plan including all types of disasters.
Ideal regional disaster management plan based on the experience
regional
disastermanagement plan based on the experience from . . . . . . . .
from the 2011Ideal
Great
East Japan
Earthquake

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The regional disaster prevention plan shall be on top of all disaster management
measures of local public body and truly effective to mitigate the disaster. The
plan must be comprehensive so that it is influential to all related planning such asurban planning. Its content shall include disaster prevention plan with clearlystated management plan to protect the lives and properties of all people and it
shall be able to sustain its minimum function against mega-scale disaster based onagreements made with related agencies and residents.
3.2 Implementation strategy
In order to make truly effective regional disaster management plan, the following
implementation strategy is proposed.
3.2.1 Structuring and practice for comprehensive management system
for minimizing disaster impact
Comprehensive countermeasures can be broken down into seven stages as shownin Figure 1, starting with disaster mitigation, preparedness, prediction and early
warning as a part of pre-disaster countermeasures and damage assessment,
disaster response, recovery and reconstruction as a part of post-disastercountermeasures. All seven countermeasures combined is called “Disaster Life

Figure 1: Total disaster management system for minimizing negative impact
Cycle” and information and communication play important role at all seven stages.
3.2.2 Disaster Countermeasure Matrix for Total Disaster Management
At all seven stages of disaster management, it is necessary to understand that the
government is not the only actor in disaster management but the collaboration
among local community and resident participation is vital. And it is necessary to
act based on the idea that one must protect one’s own life and recognize the threeforms of relief effort described as public support (PS), mutual assistance (MA)and self-help effort (SE).

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After the 1995 Kobe Earthquake, the importance of mutual assistance and selfhelp effort has been recognized, however during the 2011 Great East Japan
Earthquake Disaster, private companies’ involvement in mutual assistance andself-help effort was recognized as important, collaborating with the local people inaction such as rescue and firefighting.
Disaster Countermeasure Matrix shown in Figure 2 represents the idea that in all

Figure 2: Disaster countermeasure matrix
seven stages, there are tasks for three types of relief effort – public support,
mutual assistance and self-help effort. The countermeasure by three types ofrelief effort is often complementary to each other and it must be well-balanced. In
other words, if the work is concentrated in public support part, the cost could beenormous while if each individual put an effort and cooperate with each other, it
could be much more effective with less cost. Public support should promotemutual assistance and self-help effort rather than enhancing people’s dependency
to public support. In order to realize this situation, disclosure of information about
the disaster risk to the general public becomes important.
3.2.3 Promotion method for comprehensive disaster management
In order to efficiently conduct disaster reduction countermeasures, it is important
to make appropriate combinations of regional characteristics, target disaster types,
available time and budget at each stage. Specific procedure is as follows (Figure3). Local government offices should start by filling up the matrix with effective
countermeasures. This approach can be applied not only for earthquake andtsunami but also for all other various types of disaster. However the contents will
differ based on the type of hazard and thus Disaster Countermeasure Matrix foreach type of disaster needs to be created and all necessary disaster matrixes should
be integrated (Figure 4).

Ideal regional disaster management plan based on the experience
regional
disastermanagement plan based on the experience from . . . . . . . .
from the 2011Ideal
Great
East Japan
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Figure 4: Making of integrated action item matrix
1) Describe specific countermeasures to achieve (G: goal) in order to implement
the ideal regional disaster prevention plan as well as current situation (P:present) in Disaster Countermeasure Matrix (M).
2) The difference between the “Ideal situation M” and “Current situation M”
indicate the “Action item M” that needs to be done.
3) Fill in the responsible section, necessary time & budget and effect into the“Action item M”. It is important to work this section together with site
operators.
4) Examine available time and budget with the result of 3) and determine realistic
countermeasures that can achieve maximum effect within the given condition.
Combine the result and create project plan.
5) By practicing this process over several years, PDCA management cycle is put
into practice and effective progress management is realized (Figure 5).

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Figure 5: PDCA cycle of making action item matrix and its implementation

3.2.4 Relations among national, prefectural and city, town and village–levelgovernments
According to the Disaster Countermeasures Basic Act, the mayor of themunicipality, such as city, town, and village should have the first responsibility
for disaster operation and response. Therefore, when they discuss the disastermanagement plan and countermeasures, they tend to consider hazard, which they
can manage by themselves, as a scenario hazard. It was very difficult, or
practically impossible for them to take a consideration of much larger-scaledisaster that they could not manage and such that the local governments in

Figure 6: Three levels of players for public support

Ideal regional disaster management plan based on the experience
regional
disastermanagement plan based on the experience from . . . . . . . .
from the 2011Ideal
Great
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Vietnamaffected areas due to the 2011 Great East-Japan Earthquake faced. One of themain causes was that they put only them, municipality level government, indisaster countermeasure matrix when they discussed disaster management planand countermeasures as shown in the upper figure in Figure 6. In order to solve
this problem, they should put prefectural and national governments besides themin public support column, then, they can write what they cannot do in the columns
of prefectural and national governments. While from the prefectural governments’viewpoint, they considered that what they should do in case of disaster was just
waiting for requests from municipalities and respond them. But, prefectural
governments can recognize that when the affected municipalities cannot respondbecause of too large disaster for the municipalities to manage, without waiting forrequests from the affected the municipalities, prefectural governments should visit
the affected sites and carry out operation and response of disaster instead of theaffected municipalities. And also, when three-level governments fill all
countermeasure items together that each government should do in the bottom
matrix in Figure 6, they can recognize spontaneously duplications and/or gap
among different governments.
4. CONCLUSION
In this paper, lessons learned from the disaster due to the 2011 Great East Japan
Earthquake and Tsunami, and the subsequent reconstruction process, issues andproblems of the current regional disaster management plan are examined and theideal regional disaster management plan and its implementation strategy was
introduced. A comprehensive disaster management system was examined basedon three relief types (self-help effort, mutual assistance, and public support) andseven stages (damage mitigation, preparedness, prediction & early warning,damage assessment, disaster response, recovery and reconstruction) and a system
to categorize seven countermeasures from each stakeholders and specific action
plan with appropriate priorities were proposed.
ACKNOWLEDGEMENT
The author wishes to express his sincere gratitude to all the members of thespecial committee for regional disaster management plan established in Japan
Society for Civil Engineers after the 2011 Great East Japan Earthquake.

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Information collection and vulnerabilityof foreign students during the2011 Tohoku Earthquake and 2011 Thai flood
Michael HENRY1, Akiyuki KAWASAKI2, and Kimiro MEGURO3
Assistant professor, Division of Field Engineering for the Environment,
Faculty of Engineering, Hokkaido University, Japanmwhenry@eng.hokudai.ac.jp
2
Project associate professor, International Center for Urban Safety Engineering,
Institute of Industrial Science, the University of Tokyo, Japan
3
Professor and Director, International Center for Urban Safety Engineering,
Institute of Industrial Science, the University of Tokyo, Japan
1

ABSTRACTThe number of students studying abroad is rising around the globe, and thus it isnecessary to consider foreign students as a particularly vulnerable group and toclarify their vulnerability in disaster situations as well as understand how theycollect disaster information. This paper briefly introduces two investigations on
disaster information collection carried out after the 2011 Tohoku Earthquake and2011 Thai flood, and analyzes the results focusing on the affected foreign students
in each country. It was found that, in both disasters, foreign students were more
vulnerable than foreigner non-students, as indicated by their greater tendency toleave Japan or to be affected by the flood waters in Thailand. Within the sample
of foreign students in Japan there was a greater diversity of language levels
which could be seen to have a large affect on what language the students used toaccess media. In general, however, the primary media modes were traditional
Internet media and television. Conversely, in the case of the flood, most students
were not skilled in the local Thai language so they relied almost entirely on
English- or other-language media modes. The media they used was different thanthat used by comparable foreign students in Japan who were only skilled in
English, with a much higher usage of social media and crisis mapping.
Keywords: foreign students, language ability, Internet, social media, government
directive, earthquake, flood
1. INTRODUCTION
2011 was characterized by the occurrence of many large disasters, including theGreat East Japan Earthquake disaster and the 2011 Chao Phraya River Flood in
Thailand. One unique characteristic of these two disasters is that very large, dense,and diverse metropolitan areas were affected, both indirectly (Tokyo, Japan) anddirectly (Bangkok, Thailand).

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VietnamDuring these disasters, people in the affected areas were dependent upon disasterrelated information in order to keep abreast of the developing situation and to
make decisions, such as whether to evacuate or not. However, due to the diversityof the populations in these areas, the disaster information-related needs of theaffected people may have varied widely. In particular, Tokyo and the surrounding
Kanto area is home to the largest population of foreigners in Japan; similarly,
Bangkok is also home to a large population of foreigners, and a large number offoreign companies have industrial facilities in the area around the city.
While foreigners in disaster-affected areas represent a unique population groupwith different needs than the native population, foreign students are an even moreunique and vulnerable group due to their special characteristics: that is, they have
low economic resources but high educational level and high access to information
resources. The OECD (2010) reported that there has been a steady increase in thenumber of students pursuing education outside their own country, as from 2000 to
20007 the number of international students doubled and reached more than 2
million worldwide. As this number increases, it becomes increasingly important toconsider foreign students as a particularly vulnerable group in the event of adisaster due to cultural differences, separation from their families, their lack offamiliarity with the local language, and so forth. Therefore, it is necessary to
clarify their vulnerability in disaster situations as well as understand how theycollect disaster information in order to consider their specific needs in disaster
information dissemination systems.
In this paper, the results of two investigations on disaster information collection
after the 2011 Tohoku Earthquake and 2011 Thai flood are presented focusing
specifically on foreign students and analyzing their disaster information collection
behavior considering language ability and vulnerability compared to non-students.
2. 2011 TOHOKU EARTHQUAKE
2.1 Survey methodology
An online survey focusing on people in the Kanto region of Japan was carried out
to gather information on the information collection behavior and post-disasteraction after the 2011 Tohoku Earthquake. The details of this survey are more fullysummarized in Kawasaki et al. (2012), with Table 1 outlining the topics discussed
in this paper.
Table 1: Selected survey contents (2011 Tohoku Earthquake)
Theme
Question contents
Vulnerability Post-disaster action and reason for action
Information
Media modes utilized for disaster information collection*collection
Information
Difficulties experienced when collecting disaster information*difficulties* These questions allowed for multiple responses

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2.2 Sample characteristics & categorization
The survey received 1,357 responses. Foreigners made up 63.1% (856) of the total,
with responses from 73 different countries, and respondents who identified
themselves as students made up 50.9% (436) of that number. Further details on
the foreign respondents’ demographics are available from Henry et al. (2011).
A previous study examining the relationship between language ability andinformation collection behavior found that foreign respondents with differing
English and Japanese language abilities gathered information in distinctly
different ways (Kawasaki et al., 2012). In order to explore this phenomenon forforeign students, the student sample was categorized based on their Japanese andEnglish proficiency (Table 2). From these results, three distinct groups wereextracted: those highly skilled in both Japanese and English (JPN+ENG), thosehighly skilled in English only (ENG only), and those highly skilled in Japanese
only (JPN only). While these three groups represent the most extreme cases oflanguage ability, it can be seen that a majority of foreign students’ language
abilities fall somewhere between these selected extremes.
Table 2: Language ability distribution of foreign students (N=436)
Japanese proficiency (speaking/listening)
Advance
NativeInter.
Basic
Noned
JPN+ENG: 55
66
ENG only: 90 (20.6%)(12.6%)(15.1%)
46
57 (13.1%)
43 (9.9%)(10.6%)Englishproficiency

NativeAdvanced
Intermediate
Basic
JPN only: 34 (7.8%) 25 (5.7%)
6 (1.4%)None
Note: 14 respondents (3.2%) did not provide their complete language ability
information
The analysis of the post-disaster action and its associated reason was carried out
comparing foreign students with non-students. Selected demographic
characteristics of these two groups are summarized in Table 3. As may be
expected, students tended to be younger and have lower annual income.

Informationcollection
and vulnerabilityof foreign
students during the 2011 Tohoku
Information collection
andvulnerabilityof foreign students
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Table 3: Characteristics of foreign students and non-students in Japan (N=856)

Govt.
adv.

Annualincome(106 JPY)

Age

Demographics
20-29
30-39
40-59
60 or higher
Other, no response< 1.951.95 to 6.95
6.95 to 18
18 <No response
G1 (most cautious)
G2 (less cautious)
G3 (no specificadv.)

Students (n=436)
Freq.
%
336
77.1%
90
20.6%
0
0
10
2.3%
234
53.7%
2
0.5%
1
0.2%
2
0.5%
197
45.2%
78
17.9%
271
62.2%
87

20.0%

Non-students (n=420)
Freq.
%
0
67
16.0%
279
66.4%
43
10.2%
31
7.4%
56
13.3%
118
28.1%
29
6.9%
80
19.0%
137
32.6%
129
30.7%
239
56.9%
52

12.4%

This analysis also examined the effect of government advisory on post-disasteraction. After the earthquake, foreign governments issued advisories of varying
levels, from very cautious (Group 1: advising their citizens to leave Japan) to lesscautious (Group 2: advising limiting travel to certain areas) to no specific advisory(Group 3). Based on their nationality, respondents could thus be classified into
three groups depending on the advisory level of their home government(Kawasaki et al., 2013). The distributions of students and non-students bygovernment advisory is also given in Table 3, where it can be seen that students
appeared more likely than non-students to come from countries with either a lesscautious advisory or no specific advisory at all.
2.3 Utilized media and information difficulties by language ability
The media modes utilized by foreign students are shown in Figure 1 and theaverage number of utilized modes are summarized in Table 4 by language ability.
The most-used mode for foreign students skilled in both Japanese and English was
Japanese television, followed by Japanese and English traditional internet media,
which were all used by more than 60% of respondents. While Japanese was thedominant language for many modes, more respondents used other languages thanJapanese or English when communicating interpersonally, whereas English was
the most-used language for social media. This diversity of media usage isreflected in the average number of modes per respondent by language. For
students skilled only in English, however, English traditional internet media was
the most-used media mode, followed by English television and English social
media. English was the most-used language across all modes, and other languages
were generally more utilized than Japanese, as can be seen when looking at the
average number of modes per respondent. The case of foreign students only
skilled in Japanese, however, is the opposite of the previous group: English isbarely used and Japanese-modes are dominant – particularly television and434

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traditional internet media. Unlike students skilled in English, however, there is agreater usage of other language media.

Figure 1: Utilized media of foreign students in Japan by language ability
Table 4: Average number of utilized media modes per respondent
Media mode
language
Japanese
EnglishOther

Japanese+ English
3.15
2.35
1.93

Language ability group
English only
0.66
2.82
0.96

Japanese only
3.53
0.06
1.65

Figure 2 shows the various information difficulties of the foreign students by theirlanguage ability. Confused by conflicting and differing information was the mostcited reason regardless of language ability, with more than 70% of respondents ineach group indicating they experienced that problem. A much larger disparity
could be seen for the difficulty caused by inability to understand due to language
ability: while 64% of students skilled only in English experienced this problem,
only 11% of those skilled in both Japanese and English had the same difficulty.
The inability to access information due to mobile congestion, power outage, etc.
was also relatively highly cited among the three groups.
N=179
Unable to access information(mobile congestion, power outage,
etc.)

56%

39%
47%

76%
72%
74%

Confused byconflicting or differing information
11%

Couldn't understand(language ability)

64%

3%

Couldn't understand(terminology)

18%
18%
21%

Unable to find information(difficulty in searching or locating)

16%
23%
12%
0%

20%

JPN+ENG (n=55)
ENG only (n=90)
JPN only (n=34)

40%
60%
80%
% Respondents

100%

Figure 2: Information difficulties of foreign students in Japan by language ability
Informationcollection
and vulnerabilityof foreign
students during the 2011 Tohoku
Information collection
andvulnerabilityof foreign students
duringEarthquake
and
2011
Thai
flood
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2.4 Post-disaster action by country directive
The vulnerability of foreign students in Japan was compared to that of nonstudents while examining the effect of government directive. The results for postdisaster action are given in Figure 3. It could be seen that the percentage ofstudents who chose to leave Japan increased as the severity of the government
directive increased, with 2.8 times more students from Group 1 countries leaving
than from Group 3 countries (by percentage). Correspondingly, the ratio ofstudents who chose to remain decreased as the advisory level increased, whereas
there was only a small fluctuation in the percentage who merely relocated within
Japan. Compared to students, non-students tended to leave Japan less, regardlessof the advisory level, and also appeared less affected by the government advisory.
Figure 4 shows the reasons for post-disaster action. Among students who
remained, the most-cited reason was personal decision, with little difference
between the advisory levels. However, job obligation was cited by students fromGroup 1 countries more than twice as often as by students from other countries.
For students who chose to relocate, family request was the most-cited reason,
followed by personal decision. The government advisory level did not appear tohave much effect on the reason for relocation, except among students who cited
government directive or unable to leave as their reasons, for which thepercentages were much higher for students from Group 1 countries. Finally,among students who left Japan entirely, the most-cited reason was again family
request, followed by personal decision. In this case, however, students fromGroup 3 countries appeared more likely than students from other countries to cite
personal reason as their motivation for leaving Japan.
Students
Left

Relocated

Non-students
Remained

100%
24%
46%
67%

25%

40%
20%
0%

55%

15%
18%

N=436

21%

Group 1(n=78)

28%
Group 2(n=271)

Group 3(n=87)

80%% Respondents% Respondents

80%
60%

Left

Relocated

100%
41%

20%
0%

N=420

17%
17%

15%

60%
40%

32%

Remained

22%36%Group 1(n=129)53%

Group 2(n=239)65%

Group 3(n=52)

Figure 3: Post-disaster action of foreign students and non-students

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Remained (N=139)
Personal decision

Students

58%
55%
Personal decision
67%

Family request

75%
Familyrequest
80%
78%

7%
1%
2%

Family request
Job obligation

19%
21%

Concern for the young

1%
4%

Government directive

14%
16%
25%

Unable to leave
0%43%

Job obligation

Concern
for theGroup
1 young(n=14)

6%
10%

Relocated (N=99)

93%
Personal
84% decision
88%

3%

4%

Group 3
Unable to leave(n=48)

4%

20% 40% 60% 80% 100% 0%% Respondents

Non-students

9%
2%
3%

57%
52% Job obligation
41%

Job obligation
Concern for the young

11%
2%
9%

Government directive

6%
5%
15%

Unable to leave

13%
11%
15%
0%

Concern
for theGroup
1 young(n=47)
Group directive
2
Government(n=126)
Group 3
Unable to leave(n=34)

20% 40% 60% 80% 100% 0%% Respondents

Group 3(n=21)

20% 40% 60% 80% 100%
% Respondents

Left (N=139)

55%
Personal decision
56%
44%
17%

11%
11%

47%
33%
34%

47% Family request
33%

3%

30%
38%
15%
12%

Government directive
Group 1 (n=29)
Group 2 (n=36)
Unable to leave
Group 3 (n=9)

66%

55%
67%

13%
14%

Job obligation
34%
36%
Concern for the young
56%

7%Group 2(n=125)

4%Group 3
Unable to leave(n=18)

Relocated (N=74)

Family request

Group 1(n=52)

13%6%
5%

20% 40% 60% 80% 100% 0%% Respondents

77%
Personal
decision
83%
85%

Family request

2%
6%
14%

Group directive
2
Government(n=69)

25%

Remained (N=207)
Personal decision

2%
2%
5%

Concern
for theGroup
1 young(n=12)

17%

71%

87%
84%
76%

Job obligation

8%
9%Group directive
2
Government(n=77)Left (N=198)
37%
46%

2%

20% 40% 60% 80% 100% 0%% Respondents

56%

Group 1 (n=53)
Group 2 (n=77)
Group 3 (n=9)

20% 40% 60% 80% 100%
% Respondents

Figure 4: Reason for post-disaster action of foreign students and non-students
Compared to foreign students, non-students who remained more highly cited job
obligation, with the percentage of respondents increasing slightly with an increasein the severity of the government directive. The responses of non-students who
relocated or left Japan entirely, however, was markedly different from that ofstudents: a greater percentage of non-students cited concern for the young and job
obligation, whereas fewer non-students cited family request. Additionally, thegovernment directive appeared to have a larger effect on non-students who choseto relocate or evacuate, particularly those who cited personal decision, family
request, and concern for the young.
3. 2011 THAI FLOOD
3.1 Survey methodology
Data on information collection behavior and vulnerability were collected using asurvey similar to that used for the investigation after the 2011 Tohoku Earthquake.
Complete details of the survey contents and collection methodology are given in
Henry et al. (2012), but the topics addressed in this paper are summarized in Table
5. Furthermore, unlike the prior investigation, the 2011 Thai flood survey was
distributed via two methods: an anonymous online survey and a paper-based fieldsurvey which collected responses directly from people in the field.
Information collection and vulnerability of foreign students during the 2011 Tohoku
Information collectionof foreign students during
Earthquakeand
andvulnerability
2011 Thai floodthe 2011 Tohoku Earthquake and 2011 Thai flood

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Table 5: Selected survey contents (2011 Thai flood)
Theme
Question contents
Situationofflooding
andevacuation
Vulnerability
Information
Media modes utilized for disaster information collection*collection
Information
Difficulties experienced when collecting disaster information*difficulties* These questions allowed for multiple responses
3.2 Sample characteristics and categorization
In total the survey received 975 responses, of which foreign respondents made up
21.5% (210 responses) representing 28 countries. Among these, 46.7% (98people) identified themselves as students. A detailed overview of the foreign
respondents’ demographics can be found in Henry et al. (2012).
For understanding information collection behavior the students’ language ability
was first examined (Table 6). Unlike the case of the 2011 Tohoku Earthquake
investigation, very few students were highly skilled in Thai and English and none
were skilled in Thai only; furthermore, only 67 could be classified as highly
skilled in English only. Therefore, for simplicity, the analysis of informationcollection was conducted without any categorization of the students.
The analysis of vulnerability was conducted by comparing foreign students tonon-students. Table 7 shows that, compared to non-students, students tended to be
younger, have much lower income, and live outside Bangkok.
Table 6: Language ability distribution of foreign students (N=98)

Englishproficiency

NativeNativeAdvanced
Intermedia
te
Basic
None

Thai proficiency (speaking/listening)
Advance
Inter.
Basic
d

None

2 (2.0%)2 (2.0%)67 (68.4%)

2 (2.0%)-23 (23.5%)--

2 (2.0%)

Table 7: Characteristics of foreign students and non-students in Thailand (N=210)

Age

Demographics

438

20-29
30-39
40-59
60 or higher
Other, noStudents (n=98)
Freq.
%
70
71.4%
22
22.4%
2
2.0%
0
4
4.1%

Non-students (n=112)
Freq.
%
11
9.8%
42
37.5%
49
43.8%
9
8.0%
1
0.9%

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Livingarea

Annualincome(103 USD)ICUS Report 73

response
Very low (<3.2)
Low (3.2 – 4.8)
Middle (4.8 – 16)High (>16)
No response
BangkokGreater Bangkok
Sub-central
Other

34
6
4
10
44
9
88
1
0

34.7%
6.1%
4.1%
10.2%
44.9%
9.2%
89.8%
1.0%
-

26
3
10
58
15
71
30
3
8

23.2%
2.7%
8.9%
51.8%
13.4%
63.4%
26.8%
2.7%
7.1%

3.3 Utilized media and information difficulties
Figure 5 summarizes the media modes utilized by foreign students during the2011 Thai flood. The most-utilized mode was crisis mapping at 64%, followed bydirect communication tools (61%) and social media (51%), all of which wereprimarily utilized in English. Very little usage of Thai or other-language media
could be observed. The foreign students used, on average, 3.01 different English
media modes.
The information difficulties experienced by the foreign students are summarized
in Figure 6. The two most-cited difficulties were being confused by conflicting ordiffering information and being misled or confused by rumors and/or exaggerated
or false information, which were encountered by 70% and 67% of the respondents,
respectively. The next highest difficulty was unable to understand information due
to a lack of language comprehension, at just under 50%.
3.4 Situation of flooding and evacuation
In order to examine the vulnerability of foreign students during the 2011 Thai
flood, two factors were examined: first, whether they were affected by the flood ornot; and second, whether they chose to evacuate or not. In Figure 7, it can be seenthat the percentage of students who were flooded was more than twice that of nonstudents. However, Figure 8 shows that students were more likely to haveevacuated than non-students.

Informationcollection
and vulnerabilityof foreign
students during the 2011 Tohoku
Information collection
andvulnerabilityof foreign students
duringEarthquake
and
2011
Thai
flood
the 2011 Tohoku Earthquake and 2011 Thai flood

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Radio

Printed media
Inter-personal(N=98)

39%
61%

4%
2%

Social media

51%

2%
2%

Crisis mapping

20%

40% 60% 80%% Respondents% Respondents

80%

Not flooded

40%

76%
66%

20%
0%

N=210

Flooded

34%

60%

24%
Students(n=98)

49%

Misled or confused (rumors
and/or exaggerated or false
information)

67%

Confused by conflicting ordiffering information70%

Non-students(n=112)

Figure 7: Flooding situation of foreign
students and non-students

20%
0%

100%

Figure 5: Utilized media of foreign
students in Thailand
100%

24%

Did not have informationdifficulties

64%

16%
0%

(N=98)

9%

Couldn’t understand(language ability)

30%

3%
5%

Directcomm. tools

Unable to access information(mobile congestion, power
outage, etc.)
Unable to find the information(difficulty in searching or
locating)

3%
6%

Traditional
internet media

Thai
English
Other

38%

1%
2%
8%
0%
4%
8%
3%
3%

Loudspeaker

Internet

11%

20% 40% 60% 80% 100%
% Respondents

Figure 6: Information difficulties offoreign students in Thailand
100%% Respondents

2%
2%
1%

Television

Evacuated

Didn't evacuate

80%
60%
40%
20%
0%

N=92

98%

74%

2%

26%

Students(n=65)

Non-students(n=27)

Figure 8: Evacuation action of foreign
students and non-students(for flooded respondents only)

4. DISCUSSION
4.1 Information collection
When examining the information collection, distinctly different behavior could beobserved between the foreign students in Japan and Thailand. In the case of Japan,
the language ability of foreign students was more diverse than that of foreign
students in Thailand. While the media language was strongly affected by language
ability, there was less of a difference in the utilized mode; the most-utilized modes
were television and traditional internet media regardless of language ability. The
most-cited information difficulty, confused by conflicting or differing information,
was also similarly cited regardless of language ability; however, a large difference
could be seen for the difficulty unable to understand due to language difficulties,
which was very strongly cited by foreign students skilled only in English butbarely noted by students with other language abilities.

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The language ability of the Thai students was less diverse, with the majority ofthem being moderately to highly skilled in English. Comparing this group to theforeign students in Japan skilled only in English, it can be seen that the foreign
students in Thailand utilized internet-based media much more and television muchless than the students in Japan. In both cases, being confused by conflicting ordiffering information was the biggest difficult, but foreign students in Thailand
had less of a tendency to cite language difficulties. This may be that, due to theirusage of only English-language media modes, they did not have to deal with Thailanguage information, whereas foreign students in Japan may have encountered
more Japanese-language information in their information seeking.
4.2 Vulnerability
The analyses found that both the foreign students in Japan and in Thailand
appeared to be more vulnerable to the effects of the respective disasters, but thereason for that vulnerability differs. In Japan, foreign students were more likely to
relocate or leave Japan than non-students, and were also more affected by thegovernment advisory level than non-students. When examining the reason for the
relocation or evacuation, family request was much stronger for this group than for
non-students, regardless of advisory level. These results suggest that disaster
information dissemination not only in Japan but also in overseas countries may
have a large effect on the post-disaster decision making of foreign students inside
Japan due to the perception of foreign students’ families of the severity of thedisaster event as perceived from their home country.
On the other hand, the vulnerability of foreign students in Thailand may beclosely related to their location of residence. It was found that students were more
likely to have been flooded than non-students, but it could also be seen thatstudents were more likely to live outside the Bangkok area than non-students.
This may be due to the distribution of universities outside the city center as wellas the concentration of wealthier foreigners in the city proper. Since the areas
around Bangkok were more likely to be flooded, this would help explain why
students were more vulnerable. However, among those respondents who were
flooded, students were more likely to evacuate. In this instance, non-students may
be more likely to have family or possessions which could have hindered
evacuation compared to students, who are generally more mobile.
5. CONCLUSION
This paper found that foreign students are vulnerable to disasters in different ways
than non-students and that, furthermore, even among foreign students thedifference in language ability can strongly affect how those students gather theirdisaster information. The type of disaster or location where students are studying
may also have an affect on this collection behavior and, certainly, on theirvulnerability. Considering the trend towards greater globalization and theanticipated growth of foreign students into the future, disaster-prone countries
with high numbers of foreign students should consider them as a particularly
vulnerable group and prepare means to support them in the event of a disaster.
Informationcollection
and vulnerabilityof foreign
students during the 2011 Tohoku
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andvulnerabilityof foreign students
duringEarthquake
and
2011
Thai
flood
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ACKNOWLEDGEMENT
This research was partially supported by the Japan Society for the Promotion of
Science (Challenging Exploratory Research: “Investigation on disaster
information dissemination to foreigners after the great earthquake in the Tokyo
metropolitan area”). In addition, the authors would like to express their gratitude
to everyone who cooperated with and supported these investigations.
REFERENCES
Kawasaki, A., Henry, M., Meguro, K., 2012. Analysis of disaster information
gathering behavior and language ability after the 2011 Tohoku Earthquake. 2012
New Technologies for Urban Safety of Mega Cities in Asia (ICUS Report 201203), Ulaanbaatar, Mongolia, 263-271.
Kawasaki, A., Henry, M., Meguro, K. 2013. Advisories by foreign governments
and the behavior of foreigners residing in Japan after the 2011 Great East Japan
Earthquake. Journal of the Institute of Social Safety Science, submitted. (inJapanese)
Henry, M., Kawasaki, A., Meguro, K., 2011. Disaster information gathering
behavior after the Tohoku Earthquake Part 2: Results of foreign respondents. 2011
New Technologies for Urban Safety of Mega Cities in Asia (ICUS Report 201102), Chiang Mai, Thailand, 149-161.
Henry, M., Kawasaki, A., Meguro, K., 2012. Disaster information collection by
Thai and foreigners during the 2011 Thai flood. 2012 New Technologies for
Urban Safety of Mega Cities in Asia (ICUS Report 2012-03), Ulaanbaatar,
Mongolia, 43-54.
Organization for Economic Cooperation and Development (OECD), 2010.
International Migration Outlook: SOPEMI 2010 English Summary.
http://www.oecd.org/migration/mig/45612617.pdf (Accessed Sept. 13, 2013)

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Risks from in-city construction works
to urban inhabitants’ safety in Hanoi:
the city residents’ perspective
NGUYEN Duy Cuong1, MA Xuan Minh2 and NGUYEN The Quan3
1
Undergraduate student, University of Civil Engineering, Hanoi, Vietnam
3
PhD, Vice Dean, Faculty of Construction Economics and Management,
University of Civil Engineering, Hanoi, Vietnam
nguyenquan.nuce@gmail.com
ABSTRACTIn a growing city like Hanoi, there always are lots of construction works being
carried out while the city is still in operation. The construction processes in thoseprojects, if not being managed properly, can create risks that have negative
impacts on urban inhabitants’ safety, leading to accidents or a lower living
quality of the city’s residents which harms the city’s sustainable development.
This paper presents the results from a research into the safety risks from in-city
on-going construction works in Hanoi. The paper lists out twenty four risks fromthe construction works to urban inhabitants’ safety that are perceived by thesurveys’ participants. The risks are then classified into twelve categories with
their causes and analyzed to measure their probability of occurrence and impact.
It is concluded that “construction noise”, “construction dust”, and “constructionwaste” become the most significant causes to urban residents’ safety. Urban
inhabitants care much more about their living quality than life safety regarding
safety risks the in-city projects may bring to them.
Keywords: safety risk, urban inhabitants’ safety, in-city construction works.
1. INTRODUCTION
The development of a city can be seen in two major ways: new urban areas arebuilt up next to the current cities and old construction works inside the city aredestroyed for new construction. Some cities apply both of the ways: together withbuilding up new urban areas in the surrounding green fields, there are lots ofconstruction works being conducted in the city while the city is still in operation.
According to Biddy (2009), cited by Spillane, Oydele et al (2011), an expansionof urban centers may not be seen very clearly and fast, they are being
redeveloped from inside of the city. Being considered as one of the fastest
developed cities in Vietnam, Hanoi has experienced similar situation with lots ofprojects being carried out in the inner city. Those construction works, more or less,influence the life safety and living quality of the city inhabitants. This paper will
investigate the risks caused by construction activities to urban residents, under
their perspective.

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2. LITERATURE REVIEW
Risk can be defined as “an uncertain event or condition that, if it occurs, has apositive or negative effect on one or more project objectives such as scope,schedule, cost, and quality” (PMI 2012), p.310). When investigating a risk, it isnecessary to look at two elements: the happening likelihood or probability, andthe consequences or impacts if the risk happens (Cooper, Grey et al. 2005), p.3).
The Merriam-Webster Dictionary defines safety as “freedom from harm or
danger”, “the state of not being dangerous or harmful” (Merriam-Webster 2013).
However, in construction, safety can also mean “health”, because safety andhealth are being managed together and in the same way (Holt 2008), p.3).
Consequently, safety risk can be regarded as something that is likely to go wrong
and harm the safety. Safety risk are related to accident, which is “an incident plus
its consequences” or “an undesired event, which results in physical harm and/or
property damage”, as well as to hazard – “the potential to interrupt or interferewith a process or person” (Holt 2008), p.3).
There have been a number of works in the literature writing about safety inconstruction projects. Researchers and practitioners in the field are concernedmuch about measuring accidents in construction (Ale, Bellamy et al. 2008),
occupational health and safety (Rikhardsson 2006; Badri, Nadeau et al. 2012),
developing and managing safety management systems of construction sites(Ismail, Doostdar et al. 2012), developing tools for safety risks analysis andprevention (Gangolells, Casals et al. 2010; Aminbakhsh, Gunduz et al. 2013),
reviewing laws and regulations on safety in construction (Baxendale and Jones
2000). Some are concerned about the planning and management of construction
processes in confined, narrow construction sites with regard to health and safetyissues (Spillane, Oyedele et al. 2011). Others go for specific solutions for selectedissues on the sites such as noise emission (Ballesteros, Fernández et al. 2010),
motivation for safe work (Helander 1991), constructing road safety (Ma, Shao et
al. 2011), etc. Regarding the impact of construction works in city to the city
citizens, several works have been found from the literature, including the safety
management in construction of tunnel in city (Ding, Zhang et al. 2014), risk fromconstruction of adjacent buildings such as deep excavation (Shin, Kim et al. 2006;
Abdel-rahman 2007), managing risk for pedestrian (Bilton 2012), etc. That is tosay, there is very limited research having been done in terms of safety risk to citydwellers from in-city construction works.
3. THE RESEARCH APPROACH
As stated above, there are very limited references found in the literature relevantto the topic of risks from in-city construction works to urban inhabitants’ safety.
Therefore, a combination of exploratory and descriptive approaches would be themost suitable research approach to be adopted for this study. A questionnaire was
first designed for the purpose of data collection. 60 questionnaires then have been
completed with face-to-face mode of interview. However, since the datacollection process was very slow, the questionnaire was converted into an online
survey using Google Form. 83 people have responded to the survey, but only 54

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questionnaires are accepted to be used in the research, making it 114 completed
questionnaires in total. Those additional questionnaires also add in several
respondents who have been impacted by an on-going construction work inside thecity in regularly passing by and/or working nearby.
Table 1: Categories of respondents
No

Categories

1
1.1
1.2
1.3
1.4
1.5
1.6
2
2.1
2.2
2.3
3
3.1
3.2
3.3
3.4

Age group
Under 30
30-39
40-49
50-59
60+
Not answer
Sex
Male
FemaleNot answer
Education
Secondary and lower
University graduate
Post-graduate
Not answer
Total

No of
respondents%

38

31.93%

19
21

15.97%
17.65%

14

11.76%

46
49
19

38.66%
41.18%
15.97%

29
50
5
30
114

24.37%
42.02%
4.20%
25.21%
100.00

Table 1 presents the research sample using several categories. The data show that
respondents are dispersed over a wide range in terms of age, sex and education.
The sample includes all groups of people being classified by the aforementioned
criteria. Since internet access is more popular to younger people than to the older,this explains the significantly bigger number of respondents from the age group ofunder 30 most of whom participated in the survey through responding to theonline questionnaires.
Table 2: Type of construction works and their modes of impact to participants
No
1
1.1
1.2
1.3
1.4
2
2.1
2.2
2.3

Categories
Type of construction work
Buildings
Urban roads
Bridges (overbridges)
Tunnels, underground cellars etc.,
Mode of impact
Regularly passing by
Living nearlyWorking nearly
Total

No of respondents

%

52
27
27
8

43.70%
22.69%
22.69%
6.72%

39
69
6
114

32.77%
57.98%
5.04%
100.00Risks construction
from in-city construction
works
to urban inhabitants’safety in Hanoi: the city
Risks from in-city
works to urban
inhabitants’safety in Hanoi:
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In terms of construction works that the survey participants have been impacted,
they can be put into 4 large groups: (1) buildings, (2) urban roads, (3) bridges(overbridges), (4) tunnels, underground cellars and open trenches (Table 2).
Among three modes that those construction works can have influence on urban
citizens, the survey participants mentioned “living nearly” the most (57.98%),
then “regularly passing by” (32.77%) (Table 2). Of course, there are lots of people
who might be impacted by in-city construction works in more than a mode, yet
the respondents were asked about the work that brings them the greatest impacts.
4. RESULTS AND DISCUSSIONSThe survey results show that the on-going construction works in Hanoi can havebad influences on urban inhabitants, and therefore, can create causes that bringrisks to them. Table 3 presents the results of grouping the risks with regard to theircauses, presenting the results in descending order in terms of the total number ofbeing mentioned in the survey for the risk causes. Twelve causes have emerged
from the survey, according to information provided by the respondents. Twentyfour risks then have been identified. Among them, “construction dust causing
respiratory disease” becomes the most popular risk, being mentioned by 23.33%of the respondents. The next popular ones include “construction noise – causing
insomnia or sleeping difficulties”, “construction noise – causing stress andinhibition”, “reduction of road areas – causing traffic jams”, “construction waste –causing hygienic problems for the environment and citizens’ health” and “fallingmaterials – causing accidents to citizens” with the occurrence rates vary from
5.76% to 14.85% (see Table 3). That is to say, the risks identified harm the city
residents in both their life safety and their living quality.
Table 3 also presents the risks in terms of their level of occurring probabilities andimpact levels. Low probability of occurrence is scored 1 while high probability ofoccurrence is assigned a score of 3. Similarly, impact levels are assigned scorefrom 1 to 3. Average scores for both the occurring probabilities and impact levels
then are calculated. According to the results, the top five risks in terms ofoccurring probability are “construction dust - causing hygienic problem for theenvironment”, “construction dust - causing eye disease”, “construction waste causing drainage system’s block leading to flooding”, “construction workers causing social evil/crime surrounding the construction sites” and “construction
noise - causing stress and inhibition” (risks coded 2.2, 2.3. 4.4, 11.2 and 1.2), but
if their occurrences in the survey being taken into account, the top five change to“construction dust - causing respiratory disease”, “construction noise - causing
insomnia or sleeping difficulties”, “construction noise - causing stress andinhibition”, “reduction of road areas - causing traffic jams” and “constructionwaste - causing hygienic problems for the environment and citizens’ health” (risks
coded 2.1, 1.1, 1.2, 3.1 and 4.1). With regard to impact levels, the top five risks
include “construction dust - causing eye disease”, “construction dust - causing
hygienic problem for the environment”, “construction noise - causing stress andinhibition”, “reduction of road areas - causing traffic accidents”, “constructionwaste - causing drainage system’s block leading to flooding” and “construction
workers on site - causing theft and burglary” (risks coded 2.3, 2.2, 1.2, 3.2, 4.4
and 11.1 – the last two have the same risk level). If their occurrences in the survey

446

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Construction noisecausing
insomniaorsleeping difficulties
causing stress and inhibition
causing working distraction
Construction dust
causing respiratory diseasecausing hygienic problem
for the environment
causing eye disease
Reduction of road areas due
to construction sites
causing traffic jams
causing traffic accidents
Construction wastecausing hygienic problems
for the environment andcitizens’ healthcausing traffic jams
causing traffic accidents
causing drainage system’s
block leading to flooding
causing
damageto1
1.1

Risks from in-city construction works to urban inhabitants’ safety in Hanoi:
the city residents’ perspective

4.5

4.2
4.3
4.4

3.1
3.2
4
4.1

2.3
3

1.2
1.3
2
2.1
2.2

Risk categorized by causes

No
26.97%
14.85%
11.82%
0.30%
24.45%
23.33%
1.82%
0.30%
13.64%
10.61%
3.03%
9.09%
6.06%
1.52%
0.61%
0.61%
0.30%

49
39
1
84
77
6
1
45
35
10
30
20
5
2
2
1

%

89

Occurrencesin the survey

0
0

1
0
1

5
0

0
1

8
2
0

23
8

0
0

32

1
0
0

15
9
1

2
0

11
3
1

7
2

6
1

44

32
29
0

3.00
2.00

2.50
2.60
2.00

2.06
2.20

3.00
3.00

2.56

2.61
2.72
2.00

Occurring probability
Average High Average
2
3
score

2
1
0

Low
1

0
0

1
1
0

8
0

0
0

7

3
2
0

Low
1

1
1

12
2
2

19
4

1
0

25

21
10
1

1
0

7
2
0

8
6

5
1

45

25
27
0

Impact level
Average High2
3

Table 3: Risks categorized by causes and their occurrence in the survey, occurring probabilities and impact levels

2.50
2.00

2.30
2.20
2.00

2.00
2.60

2.83
3.00

2.49

2.45
2.64
2.00

Averagescore

ICUS Report 73

447

448

11.1
11.2

10.1
11

10

9.1

8.1
9

8

7.1

5
5.1
5.2
6
6.1
7

No

commuting vehicles
Road damage
causing traffic jams
causing traffic accidents
Falling materials
causing accidents to citizens
Adjacent buildings’ sinking
and cracking
harming safety of people
next door
Brokenandcollapsed
equipment
causing accidents to citizens
Vibrationdue
toconstruction activities
causing
damagestosurrounding buildings
Lacking of lighting andsignboards
causing traffic accidents
Public disorder due toconstruction
workers’
coming to the sitecausing theft and burglarycausing social evil/crime

Risk categorized by causes

0ctober 2013, Hanoi, Vietnam

3.64%
3.44%
3.33%
1.82%
1.82%
1.21%
1.21%
1.21%
0.61%
0.61%

11
11
6
6
4
4
4
2
2

3.64%

12
12

6.67%
3.64%
3.03%
5.76%
5.76%

%

22
12
10
19
19

Occurrencesin the survey

0
0

0

0

2

1
0

2

2

5

9

10

1

3

4
6

New Technologies for Urban Safety of Mega Cities in Asia

2.50
3.00

2.50

2.67

2.18

1.75

1

1.33
1.60

0
0

1

3

4

1

4

0
0

Low
1

1
2

1

1

4

5

11

8
6

1
0

2

2

3

6

4

4
4

Impact level
Average High
2
3

2.50
2.00

2.25

1.83

1.91

2.42

2.00

2.33
2.40

Averagescore

New Technologies for Urban Safety of Mega Cities in Asia

1
2

2

4

4

0

8

0
0

Occurring probability
Average High Average
2
3
score

8
4

Low
1

October 2013, Hanoi, Vietnam

Risks from in-city construction works to urban inhabitants’ safety in Hanoi:
the city residents’ perspective

surrounding the construction
sites
Material trucks commuting
causing traffic jams
causing traffic accidents
Total

12
12.1
12.2

4
2
2
330

Occurrencesin the survey

1.21%
0.61%
0.61%
100%

%

0
0
29

Low
1

1
1
140

1
1
161

2.50
2.50
2.40

Occurring probability
Average High Average
2
3
score

Risks from in-city construction works to urban inhabitants’ safety in Hanoi: the city residents’ perspective

Risk categorized by causes

No

0
0
35

Low
1

2
2
142

0
0
153

Impact level
Average High
2
3

2.00
2.00
2.36

Averagescore

ICUS Report 73449

October 2013, Hanoi, Vietnam

is considered, the top five of risks in terms of impact level change to “construction
dust - causing respiratory disease”, “construction noise - causing insomnia orsleeping difficulties”, “construction noise - causing stress and inhibition”,“reduction of road areas - causing traffic jams” and “construction waste - causing
hygienic problems for the environment and citizens’ health” (risks coded 2.1, 1.1,
1.2, 3.1 and 4.1). It is noted that if we include the occurrence rates of the survey
respondents in the calculation, the most significant risks do not change much.
These are the risks that the respondents pay the greatest attention to because of
their occurrence and impact.
In order to rate the perceived risks, each risk’s average occurring levels is
multiplied with its impact level (Table 4). Top five of risks with the highest risk
levels include “Construction dust - causing eye disease”, “construction dust causing hygienic problem for the environment”, “construction waste - causing
drainage system’s block leading to flooding”, “construction noise - causing stressand inhibition” and “construction noise - causing insomnia or sleeping
difficulties” (2.3, 2.2, 4.4, 1.2 and 1.1). Integratedly, risk causes that may bring
the highest risk (top five) are “construction noise”, “construction dust”,“construction workers’ coming to the site”, “construction waste” and “lack oflighting and signboards”. However, when taking into account the occurrence ratesof the risks, they are “construction noise”, “construction dust”, “reduction of roadareas”, “construction waste” and “road damage”. Apparently, noise, dust andwaste are the most significant causes to risks to city dwellers from in-city
construction works. Therefore, the greatest safety issues for urban inhabitants are
related to their quality of life, not life safety. The omission of fatal and serious
injuries from the risk list supports this conclusion.
Table 4: The risk levels of the perceived risks
No

Risk categorized by causes

1
1.1

Construction noisecausing insomnia or sleeping
difficulties
causing stress and inhibition
causing working distraction
Construction dust
causing respiratory diseasecausing hygienic problem for theenvironment
causing eye disease
Reduction of road areas due toconstruction sites
causing traffic jams
causing traffic accidents
Construction wastecausing hygienic problems for theenvironment and citizens’ healthcausing traffic jams

1.2
1.3
2
2.1
2.2
2.3
3
3.1
3.2
4
4.1
4.2

450

Occurring
level
2.53

Impact
level
2.65

Risk
level
6.70

2.45
2.64
2.00
2.52
2.49

2.61
2.72
2.00
2.60
2.56

6.40
7.18
4.00
6.55
6.38

2.83
3.00

3.00
3.00

8.50
9.00

2.13
2.00
2.60
2.27

2.09
2.06
2.20
2.50

4.46
4.11
5.72
5.67

2.30
2.20

2.50
2.60

5.75
5.72

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ICUS Report 73

0ctober 2013, Hanoi, Vietnam

No

Risk categorized by causes

4.3
4.4

causing traffic accidents
causing drainage system’s blockleading to flooding
causing damage to commuting
vehiclesRoad damage
causing traffic jams
causing traffic accidents
Falling materials
causing accidents to citizens
Adjacent buildings’ sinking andcracking
harming safety of people next door
Broken and collapsed equipmentcausing accidents to citizens
Vibration due to construction
activities
causing damages to surrounding
buildings
Lacking of lighting and signboards
causing traffic accidents
Public disorder due to construction
workers’ coming to the sitecausing theft and burglarycausing social evil/crime surrounding
the construction sites
Material trucks commuting
causing traffic jams
causing traffic accidents
Total

4.5
5
5.1
5.2
6
6.1
7
7.1
8
8.1
9
9.1
10
10.1
11
11.1
11.2
12
12.1
12.2

Occurring
level
2.00

Impact
level
2.00

Risk
level
4.00

2.50

3.00

7.50

2.00
2.36
2.33
2.40
2.00
2.00

2.00
1.45
1.33
1.60
2.37
2.37

4.00
3.44
3.11
3.84
4.74
4.74

2.42
2.42
1.91
1.91

1.75
1.75
2.18
2.18

4.23
4.23
4.17
4.17

1.83

2.67

4.89

1.83
2.25
2.25

2.67
2.50
2.50

4.89
5.63
5.63

2.25
2.50

2.75
2.50

6.19
6.25

2.00
2.00
2.00
2.00
2.36

3.00
2.50
2.50
2.50
2.40

6.00
5.00
5.00
5.00
5.66

5. CONCLUSIONSThe paper has presented results from an empirical survey in terms of risks createdby construction activities in in-city projects in Hanoi. Emerging from the survey
results, twelve risk causes which create twenty four risks have been categorized
and then analyzed by their probability of occurrence and level of impact. Most of
the significant risks only harm the respondents’ living quality, not their life safety.
Among the risks, repeated top five include “construction dust - causing eye
disease”, “construction dust - causing hygienic problem for the environment”,“construction waste - causing drainage system’s block leading to flooding” and“construction noise - causing stress and inhibition”. Among the causes, noise, dust
and waste are the most significant causes to risks to city dwellers due to in-city
construction works, meaning life safety, more or less, has been ensured by the
project executors, then urban inhabitants mostly consider their living quality as
significantly important when considering in-city projects safety risks.
Risks from in-city construction works to urban inhabitants’ safety in Hanoi:
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October 2013, Hanoi, Vietnam

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Ale, B. J., L. Bellamy, et al. (2008). "Accidents in the construction industry in the
Netherlands: an analysis of accident reports using storybuilder." Reliability
Engineering & System Safety 93(10): 1523-1533.
Aminbakhsh, S., M. Gunduz, et al. (2013). "Safety risk assessment using analytic
hierarchy process (AHP) during planning and budgeting of construction projects."
Journal of Safety Research.
Badri, A., S. Nadeau, et al. (2012). "Proposal of a risk-factor-based analytical
approach for integrating occupational health and safety into project risk
evaluation." Accident Analysis & Prevention 48: 223-234.
Ballesteros, M. J., M. D. Fernández, et al. (2010). "Noise emission evolution on
construction sites. Measurement for controlling and assessing its impact on thepeople and on the environment." Building and Environment 45(3): 711-717.
Baxendale, T. and O. Jones (2000). "Construction design and management safety
regulations in practice—progress on implementation." International Journal of
Project Management 18(1): 33-40.
Bilton, P. (2012). Pedestrian Risk Management during Urban Construction
projects. Australasian College of Road Safety Conference 2012, Sydney, NewSouth Wales, Australia.
Cooper, D. F., S. Grey, et al. (2005). Project risk management guidelines:
managing risk in large projects and complex procurements, John Wiley & Sons.
Ding, L., L. Zhang, et al. (2014). "Safety management in tunnel construction:
Case study of Wuhan metro construction in China." Safety Science 62: 8-15.
Gangolells, M., M. Casals, et al. (2010). "Mitigating construction safety risks
using prevention through design." Journal of Safety Research 41(2): 107-122.
Helander, M. G. (1991). "Safety hazards and motivation for safe work in theconstruction industry." International Journal of Industrial Ergonomics 8(3): 205223.
Holt, A. S. J. (2008). Principles of construction safety, Wiley. com.
Ismail, Z., S. Doostdar, et al. (2012). "Factors influencing the implementation of asafety management system for construction sites." Safety Science 50(3): 418-423.
Ma, Z., C. Shao, et al. (2011). "Constructing road safety performance indicators
using fuzzy delphi method and grey delphi method." Expert Systems with
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Merriam-Webster (2013). "Merriam-Webster Dictionary." Retrieved 12 May,
2013, from http://www.merriam-webster.com/dictionary/safety.
PMI (2012). A guide to the Project management body of knowledge. Newtown
Square, Pennsylvania, USA, Project Management Institute.
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Shin, H.-S., C.-Y. Kim, et al. (2006). "A new strategy for monitoring of adjacentstructures to tunnel construction in urban area."
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Risks from in-city construction works to urban inhabitants’ safety in Hanoi: the city
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residents’ perspective

Increasing community awarenessof earthquake risk through children
education: A case study ofDien Bien city in Vietnam
Thi Hong PHAM 1, Pennung WARNITCHAI2, and Akiyuki KAWASAKI3
1
Graduate student, Department of Disaster Preparedness Mitigation Management
Asian Institute of Technology (AIT), Thailand
2
Coordinator and Associate Professor, Department of Disaster Preparedness
Mitigation and Management, Asian Institute of Technology (AIT), Thailand
3
Visiting Associate Professor, Asian Institute of Technology (AIT), Thailand
ABSTRACT
Raising awareness program plays an important role in mitigating earthquake
damages. However, there are still existing challenges to successfully aware
citizens about earthquake vulnerability and protection in urban areas. In thisstudy, a new approach for conducting earthquake raising awareness programs inurban communities through children education was proposed. Two hypotheses
were investigated: (1) if primary school children can learn earthquake mitigation,
which includes complicated parts in class; (2) if children can transfer earthquake
knowledge to parent in their family at home; and the exposure to this approach
can help the parent living in urban communities improve their understanding ofearthquake risk. In order to examine the hypothesis, an experiment using primaryschool children at age 10 to 12 and parent as participants was implemented. The
result shows the statistically significant differences in students’ pre and post test
performance on earthquake knowledge test. It also showed children have ability
to improve the parent’s understanding of earthquake. Thus, the high effectivenessof the approach was proved. In this research, an earthquake concern survey was
conduct to explore concern level of citizens about earthquake and factors
effecting on their concern. The results of survey showed that, earthquake ishighest concern of Dien Bien people and age, education, having earthquake
experience effected on their concern.
Keywords: Earthquake education, children education, children psychology,transforming knowledge, urban areas,
1. INTRODUCTION
Big earthquakes happening continuously in the world are becoming dangerous
threat of human being. Earthquake, depending on its magnitude and distance fromthe epicenter and location characteristics may cause a number of adverse effects
including structural damages and non-structural damages. Logically, earthquake453

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamprediction is expected to help warning people from earthquake hit; however,short-term earthquake prediction have been studying but not all of them havegood scientific explanation (CSEP, 2011), (Kirschvink, Joseph L, 2000), (Andrew
Coburn, Robin Spence, 1992). Therefore, people used to rely on countermeasures
to protec themselve from earthquake. Among of earthquake mitigation methodes,
earthquake education is becoming more and more important method because it
can find the answer for the hard question how to remind public about destructive
damages of big earthquakes which have long return period comparing to human
life. Earthquake education also creates the earthquake safety culture of a society(Parsizadeh, 2007).
The system, however, have not been adequately conducted in most coutries.
Earthquake safety in school curriculumn focuses much on earth science which is
not enough to promote risk awareness or action for earthquake protection(Wisner, 2006). Therefore, a good assessment of the role of parent in encourage
earthquake knowledge among community need to be explored (Parsizadeh, 2007).
Moreover, it was found that most of raising awareness activities are applied withhigh effectiveness in rural sides but in urban areas. A heterogeneous community
in urban area with immigrant issues and low concern about campaigns activities
would generate tensions in conducting awareness campaigns (Pelling, 2010).
This study explore the way to trainning public in city about earthquake risk
protection through children education. Earthquake safety content including fourparts: earthquake basis knowledge, preparedness for earthquake, response during
and after earthquake, was prepared for children at age 10 to 12 year olds learning.
Guidline teaching parent contact to their children and learn earthquake knowledge
was provided for the parent.
Two of the issues raised in prevous studies are addressed here. First, could
children at age from 10 to 12 learn earthquake safety which combines concent ofearthquake science and earthquake protection drills? Second, did children cantransfer what they learn in class to parent in their family at home? To ourknowldege, no research exists checking the children’s abilities in transfering
earthquake knowledge to parent in their family and teach them to protect adultfrom earthquake; therefore, the package including guiline and lectures should be
developed as a tool to raising awareness earthquake safety in urban city.

2. EARTHQUAKE EDUCATION
Earthquake formal education in this study is defined as a systematic education
model to educate about earthquake mitigation. This system is structured according
to a given set of laws and presented in the curriculum as regards objectives,content and methodology.
Curricula teaching about earthquake risk is vary largely in approach and intensity
in different countries. Iran has a nationwide earthquake safety education, for 16
million primary and secondary students (Ghafory-Ashtiany and Parsizadeh 2005)
while Bangladesh, the country frequently suffered earthquakes set up disaster

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ICUS Report 73

management chapters in the school curriculum but does not include earthquake
education. In Japan, earthquake topics have been taught in the environment anddisaster mitigation courses in 5 prefectures including Shizuok, Aichi, Wakayama,
Osaka and Hyogo for total 1065 primary and secondary schools students(Shiwaku, 2007). In developing countries, earthquake integrating in school
curriculum is limited.
Many teaching methods were applied accommodating with age of learners.
Lectures based on drill exercise, earthquake simulators, lab experiment will
employ most learning skills such as listening, writing, reporting and mapping forunderstanding and memorizing of children (Wisner, 2006). Tori Zobel, a teacher
in the CleveHill Middle School proposed integrating earthquake education intoelementary school curriculum by a whole language approach including such as art,
math, music and science (Zobel, 1992). Lab experiment about dynamic movementof the building, a bench-scale shake table program earthquake engineering
curriculum for undergraduate students (S.J. Dyke et al, 2000).
Non-formal earthquake education has been used in this research to describe thesystem that organized learning outside of the formal education with non –contiguous communication. This system includes training, drills and raisingawareness activities. Learners from different responsibilities can participate in avariety of earthquake mitigation training courses such as teachers, staffs, pupils,
authority, communities. Normally, basic knowledge about earthquake safety andearthquake preparedness in emergency case for individual safety and society
safety are offered for community level and local government. Earthquake risk
mitigation and preparedness plan are introduced to improve knowledge of theauthorities according to following main issues: Earthquake safety basis;
Emergency preparedness for individual safety and society safety; Preparedness
plan; Rescue method, triage; Earthquake evacuation. Raising awareness activities
also extended by linking with publications, demonstrations, simulations andexhibitions to remind public about destructive damage of earthquake.
4. METHODOLOGY
4.1 Survey of earthquake concern in Dien Bien city
Dien Bien is located in the Northern part of Vietnam where the active fault called
Lai Chau – Dien Bien running through has caused significant damages to local
people. According to scientists (Duong, 2010); (Thanh, 2007); (Phuong, 2011),
Lai Chau- Dien Bien Phu fault is one of the active faults in Asia, therefore,
Northern part of Vietnam especially Dien Bien city is the most vulnerable place toearthquake. Many small and medium earthquake happed in Dien Bien in the past.
Earthquakes magnitude 6.7 recorded in 1983 ruined a large number of
infrastructures and agricultural land of this area. Recently, number of earthquake
is increasing, especially, earthquake M5.3 in 2001 damaged 2916 buildings, 58
office buildings and 264 schools in Dien Bien (Duong, 2010). Nowadays, Dien
Bien has been suffered increasing number of earthquakes recently; therefore,
citizens are expected to understand about earthquake risk in their living. However,
Increasingawareness
communityofawarenessofriskearthquake
throughchildren education: A case
Increasing community
earthquake
through riskchildreneducation:
study
of
Dien
Bien,
Vietnam
A case study of Dien Bien City in Vietnam455

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamuntil now, there is lack of awareness raising program for earthquake safety in thiscity; as the result, citizens still do not know how to protect themselves when an
earthquake strikes.
To evaluate earthquake concern of people in the studying area, our researchrandomly chose 100 samples in the whole city. These respondents answered sixquestions in questionnaire about earthquake concern and their demand in thecontext of disaster mitigation. As our knowledge, no survey about earthquake
disaster concern was conducted before in this city.
4.2 Earthquake mitigation teaching tool development
As noted earlier, the first step is to develop a teaching tool to educate children
aged 10 to 12 about earthquake protection and mitigation in class.
The earthquake mitigation-teaching tool contains both earthquake training
primary children in class and guideline for parent contacting and learning fromchildren.
The first part of teaching content was designed to stimulate learning by allow
children at age 10 to 12 can understand earthquake mitigation, which iscomplicated knowledge beyond their knowledge at primary level. The designer
began by reviewing earthquake - teaching materials around the world and scienceknowledge at primary school level. The appropriated content of the earthquake
training was selected with the purpose of helping primary students understanding
and memorizing earthquake mitigation knowledge. It applied number of teaching
methods including drawing, game, watching video, drills, which helped children
enjoin in class better.
The second part of teaching tool was guideline handbook for parent contacting
and learning from children was developed. The purpose of guideline is improving
conversation between parent and their children focusing on what children learnt
about earthquake in class. The study started to interview each parent to get
information about their children’s behavior and their free time to set up aappropriated guideline for each participant.
This tool can be used by teachers, volunteers, or disaster experts in term of raising
earthquake awareness among community. Learning module with student learning
objectives and activities is presented in bellowing table.
Table 1: Earthquake mitigation teaching tool development
LecturePurpose of lecture
Materials
Activities ofchildren
What is an students understand: Fresh eggs, Drawing,
earthquake? Structure of The
boiling
watching videos
earth;
eggs,
and pictures;
Internal and external orange
coloring theirforces;Pens, color picture; observing
Cause of earthquake pencils,
and amazing
and type of
white

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movement
Earthquake in
Locationwhat arethe effectsofearthquakes

students understand:Special terms
relating about
earthquake risk:
seismic wave,
magnitude ofearthquake, intensityof earthquake,
hypocenter,epicenter of theearthquake
What to expect
during earthquake
happen? (Student
quake might see,feel, hear, during anearthquake)
Damages of anearthquake mightoccur incommunities indifferent intensity
levelsOther adverse
damages ofearthquake
How toChildren would help
prepare for their parents
preparing for ananearthquake? earthquake throughearthquake homeplan
Help students being
aware with the risk
place with earthquake
in their houses
Understanding whatshould be preparedin emergency kits
will help them
prepare thenecessary for they
won in emergency
case

papers,rulers,Pictures,projectors,
Pens, color
pencils,
white
papers,rulers,glues,
scissors,
Color
pictures,projectors,
video

play a matchinggame to recall
their knowledge;
Drawing,
watching videos
and pictures;

Picture,power
point,
Projector,

Coloring thepictures, identify
the vulnerable
place in room
Working with
their friend toshare idea about
earthquake plan
watching thevideos andpicturesobserving andamazing

Increasingawareness
communityofawarenessofriskearthquake
throughchildren education: A case
Increasing community
earthquake
through riskchildreneducation:
study
of
Dien
Bien,
Vietnam
A case study of Dien Bien City in Vietnam457

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnam

To understand thelong-term
preparation for anearthquake
What toAfter class, students
respondknow skills toduringbehave when they
earthquake? meet earthquake in
different situation.

What toresponse inpostearthquake?

After class, students
know skills to
behave in post
earthquake

Video,
projector,
pencils,
papersVideo,
projector,
pencils,piece ofpaperschildren enjoined
to practical drills;
therefore, they
will not to bepanic inemergency caseChildren watch
video and design
their own action
Children have
responded after
learning
Watching video
to memorize
During classchildren watch
videos and they
fix their own
wrong actions inpost earthquake

4.3 Experimental design
An experimental prep-test and post-test research design was used. Several factors
were taken into account in designing the experiment. Permission of experiment
was signed by heard of primary school so that the main teachers helped to contact
with parent and organized meeting. The researcher contacted directly to parent toaccess general situation of each family, which would help in writing earthquake
learning guidance for parent.
93 children were randomly chosen in two primary schools, Thanh Luong primaryschool and Hanoi- Dien Bien primary school. These students were devised into
three groups which were received different treatments in experiment process. For
group 1, previous test were introduced to children participants. Children in group
1 were taught earthquake knowledge in the 5 hours (1 hour per day). Afterteaching, participants had to do post- test to check the knowledge improvement.
Children in the second group enjoined class after testing knowledge. They also
did post test after 5 class hours but they won’t asked to share what they learnt inclass to parent in their family. In control group, children did pre-test and post-test
without class participation.
In this research, adult participation would be the parents or other family membersof children who were willing to join to the experiment. For the adult groups,
several socio-demographic variables that effect to children and parent
communication were assessed. These included children age, parent’ education and458

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family size. Base on the information, researcher chose those parent frequently
make conversations with children to participate in the experiment. Then
researcher and the main teacher contact directly to parent in the group 1 to clear
about purposes of the requirements. They were asked to read the guidance forcontact to their children do homework with them. Parent in group and in group 2
and 3 were asked to answer question in earthquake exam before and after theirchildren learning but they did not participated in learning.
4.4 Pre- and Post- examination evaluation
The pre- and post-examination are designed to measure the students’ abilities oflearning and transformation earthquake knowledge to parent in their family.
Moreover, these tests also evaluated capability of parent in the new approach. The
test consists 4 parts and associated questions. There are 3 questions were opened –ended, 2 multiple choice questions and 22 true or false question. There was 1
ranking question. Maximum score is 30 point. Higher scores indicated higher
levels of earthquake awareness, while lower scores indicated lower levels ofearthquake awareness knowledge.
The design allowed comparisons between groups and pre- and of post- test amonggroups. The main analysis is pair t-test checking the score difference in pre- andpost-examination within group. Statistically significant paired differences indicate
the students and parent in their family performed differently on the post-test. To
examine how age, education and gender impact the test score of parent
To comply with regulation on research on human subjects, both children andparent were informed the nature of research. Only those students and parent
indicated a willingness to be included in the study were included. Students andparent who did not complete research both pre and post-test were deleted from thelist.
5. RESULT AND DISCOUSSION
5.1 How people in Dien Bien concern about earthquake?
Demographic information
Gender distribution: Many researchers found men and women have different
social worries because of different responsibilities in society. In this survey,(64%) female responded which was much more than that of males (36%);
therefore, the perception of the answers would be effected because of genderviews
Age group: The human age might determine their experiences and knowledge
about social problems. In Dien Bien, old people who are more than 60 year olds
would have different perception about earthquake mitigation because they alreadyexperienced a lot of big earthquakes including a big earthquake in 1935 (M= 6.75),
1983 (M= 6.7) and earthquake in 2001 (M= 5.3). Those who are more than 30
Increasingawareness
communityofawarenessofriskearthquake
throughchildren education: A case
Increasing community
earthquake
through riskchildreneducation:
study
of
Dien
Bien,
Vietnam
A case study of Dien Bien City in Vietnam459

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamyear old suffered less big earthquake, some small earthquake including a damaged
earthquake in 2001 with magnitude is 5.3. Young people who do not haveexperience about earthquake, so they might not respond to questions in the sameas the older one.
In this survey, average of respondents 37.39 showed that most of the citizens haveexperiences about some small earthquakes especially big earthquake magnitude
5.3 in 2001. The standard deviation is age group distribution is 12.54 therefore,
the information reflected ideas of citizens at a variety of ages.
Table 2: Summarizing results of earthquake concern survey in Dien Bien city (N= 100)
Number of Percentage
respondents
Gender distribution
male
36
36%
female64
64%
Age group
14 to 25
21
21%
26 to 54
71
71%
55+
8
8%
Educational level
Primary school22%Secondary school
21
21%
High school
57
57%
Bachelor or higher
20
20%
Experience about earthquake
Have earthquake experience83
83%
No earthquake experience17
17%
Need to understand earthquake
need
69
69%
No need31
31%
Educational level: Education is the process by which the knowledge,
characteristic and behavior of respondents are formed and modified. Table 2
showed education level of respondents in Dien Bien city is also quite high withmore than 70% of citizens graduated high school degree. These people were
expected to have right access and concern about earthquake risk in their living
area. Only 2% of samples was at primary school level and 21% of total
respondents at secondary school level.
Disaster is the most worry of people in Dien Bien today
In life, people have to face with number of living problems including disaster,road accident, low income and diseases. Depending on different areas, one factor
may be more or less important than others. In this survey, local people ranked
their concerns among above problems according to weight from 1 (absolute don’t
worry) to 4 (very worry). The result showed that both disaster and low income
received the highest worry from local people average points were 3.13 and 2.9

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respectively with no significant difference in one-way ANOVA test between theTwo (p value = 0.555> 0.05). The highest mean score was disaster which show
how important role of disaster mitigation activities in this area. Disease factor androad accident got lower concern. There were no significant difference in meanscore of two this factor (p value in one way ANOVA = 0.078>0.05).
Earthquake is the most concern of Dien Bien people among disasters
Storm, flood, earthquake and landslide are four types of disaster frequently
happened in Dien Bien city. Local people ranked their concern about theses
disasters according to different worry levels from 1 to 4. The result showed that,earthquake was most worry of people in the city (mean score = 3.89). After
earthquake, storm was the second concern of local people in Dien Bien which also
had significant difference from flooding (sig value = 0> 0.05_) and landslide (sigvalue = 0< 05).
In fact, respondents live in the city, where does not locate in the flash flooding
root; therefore, this place rarely suffers from flash floods. Moreover, there are 5
lakes surrounding the city which can help people manage and reduce water flow
and store water in the raining season. Concerning about storm worry in the city,
the infrastructure including houses, road, and other constructions in the city arequite good to resist storm. Comparing to damage of other disasters, earthquake
damage 2001 in Dien Bien happened in short time but caused huge damages,
which easier to recall them their concern while responding the question.
Factors effect on local people need to understand earthquake
Success of earthquake mitigation programs at community strongly depends on theneed to understand about earthquake of local people. As the result of research
69% of respondents did not want to understand earthquake mitigation even thepercentage of people have earthquake experiment quite high, 81%.
A logistic regression test was utilized to find relation of earthquake educational
need and age, having earthquake experiment of respondents. Result of the test
demonstrated that it would predict “yes” answer success at 92% and predict “no”
answer 32.3%. in general the model can predict the decide of local people about
need or don’t need earthquake education successfully at 74%.
Table 3: Summarizing the result of checking logistic regression of relation
between the earthquake educational need of respondents and factors education,age, having earthquake experimentfactors
B
S.E. Wald
Sig.
Exp(B)
Education.717 .357 4.039
.044
2.49
age

.044

.022 4.017

.045

1.045

Earthquake
experience

1.423

.613

5.388

.020

4.150

Constant-4.022 1.538

6.797

.009

.018

Results from table 2 shows that predictors age, education and “having earthquake
experience” significant effect on earthquake educational need of local people with
Increasingawareness
communityofawarenessofriskearthquake
throughchildren education: A case
Increasing community
earthquake
through riskchildreneducation:
study
of
Dien
Bien,
Vietnam
A case study of Dien Bien City in Vietnam461

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamits sig value = 0.044, 0.45, 0.2 respectively < 0.05. The value of coefficients (Exp(B) from table 2 show there was positive relation between these predictor and theearthquake educational demand of local people. That is, the more local people got
earthquake experience, high age and higher education the more they need andunderstand about earthquake. Among of three factors, the factor “having
earthquake experience” significantly effects on demand of earthquake educationof Dien Bien people.
Where does earthquake information mostly come from?
According to our research, television is the most popular source that provides
earthquake risk information for studying the area. Other three sources such as
newspaper, radio, and the internet received less concerned from local people. The
result of analyzing SPSS also show that mean score of TV source is higher
significantly than other sources (Sig value = 0.000). The finding suggests that, forremote area, television is the best way to raise awareness about earthquake risk
5.2 Can primary children learn earthquake mitigation?
The results of the paired t-test are given in the table 2 for each of four parts (basic
earthquake knowledge, preparedness for earthquake, response during earthquake,
response in post-earthquake) plus all question combination in test. Anpha level of
5% is assumed. For control group, none of the post- and pre-test score arestatistically different (p value = 0.348).
All t-tests show significant differences between the post and pre-tests of students
in group 1 (p value = 0.000) and group 2 (p value = 0.000) who participated inclass. These significant differences indicate primary children can comprehend andlearn as the earthquake mitigation-teaching tool applied. Result also shows thatmean score in the post-examination of children group 1 with parent participationis 21.16 which is higher than that of children in group 2 without parent
participation ( the mean score =19.16). This finding may suggest that, adultparticipation would be one of the factors improve children learning disastermitigation. Previous study also confirmed this finding by concluding that kids at 5
to 6 age can learn earthquake education better when they learn with their children(Gulay, 2010).
Table 4: pre-and post-test mean score associated with the null hypothesis ofequality of pre- and post test score of students by T-test
Questions in different part
score
Total
Part 1 Part 2
Part 3
Part 4
Basic EQ
Respond Respond in
EQ
preparedness during
post EQ
EQ
Control group n = 31
Post test
11.42
4.73
2.45
2.23
2.13
mean
Pre-test
11.03
4.60
2.22
2.26
1.96
mean
P -value
0.348
0.73
0.09
0.459
0.591

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Group1 – parent participation (n = 31)
Post test
21.16
6.9
3.45
mean
Pre-test
8.13
3.06
1.39
mean
P -value
0.00
0.000 0.000
Group 2 - non parent participation (n = 31)
Post test
19.16
5.64
3.49
mean
Pre-test
11.42
3.5
1.97
mean
P -value
0.00
0.000 0.000

6.39

3.45

2

1.67

0.000

0.000

6.06

3.97

2.065

3.80

0.000

0.572

In all four parts, score of children in group 1and group 2 in post-test remarkably
higher on the pre-test with p = 0.000. From table 2, ratio mean cores in posttest
and maximum score in part 1 (6.9/7; 5.64/77) and in part 3 (6.39/7; 6.06/7) ofchildren of group 1 and 2 were higher than that in the part 2 (3.45/7; 3.49/7) andpart 4 (3.45/7; 3.97/7) . This illustrates that, the teaching tool have higheffectiveness in training basic earthquake knowledge and response during
earthquake. The reason for these successes would be, learners already have theirown perception these issues in their past in the study area. Second, children may
more concern about what to do during earthquake than other issues. Third,
teaching material was good enough to teach people. Therefore, the teaching tool
need to be more developed to provide earthquake knowledge for participants.
5.3 Can parent learn earthquake knowledge from their children?
As mentioned before, adult participants in this research were chose purposely withassume that most of them followed the guidance. Results from Two-way ANOVA
analysis combining data of all adult participants in 3 groups showed that, gender,
education and age did not have significant effected to score of parent’ pretest with
p value equal 0.08, 0.055 and 0.23 respectively.
According to table 4, while there was a significant difference in score of pre andpost-test of parent in group1, non-difference could be found in that of parent
group 2 and group 3. This result indicates those parent following the guideline andcontact frequently to children would improve their earthquake knowledge.
Table 5: pre-and post-test mean score associated with the null hypothesis ofequality of pre- and post test score of parent by T-test
Questionsscore
Mean score
Std. Deviation
P value
Control group n = 31
0.348
Post test mean
20.35
2.45
Pre-test mean
9.23
2.32
Group1 – parent participation (n = 31)
0.000
Post test mean
12.9
2.44
Pre-test mean
13.32
2.73
Group 2 - non parent participation (n = 31)
Increasingawareness
communityofawarenessofriskearthquake
throughchildren education: A case
Increasing community
earthquake
through riskchildreneducation:
study
of
Dien
Bien,
Vietnam
A case study of Dien Bien City in Vietnam463

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamPost test mean
Pre-test mean

12.42
11.13

2.28
2.58

0.521

To examine which factor have significant effects to posttest score of parent ingroup 1, two-way ANOVA showed that while education factor and age andeducation combination have significant effect on the score (p- education = 0.025,
p age-education = 0.032) age factor, gender or combination of age, education andgender factor did not effect to the score. This means parent in family in different
age, gender and education following the guidance can learn earthquake
knowledge from student.
Concerning 4 parts in content of the teaching program, mean score of parent inpart 3 was even better than that of children in part 3. That mean parent not only
learnt from their children but also have their own experience from indigenous
knowledge. Therefore, the most importance in training adult is raising awarenessfor them to get them involve in earthquake mitigation activities; from that, they
can learn and achieve knowledge by themselves. In this case, children was one of
the most important factors make them pay attention on earthquake mitigation
activities. In looking beyond this study, this approach can be used effectively toraising awareness about earthquake protection in urban city.
6. CONCLUSIONS
While earthquake cannot be predicted accurately, raising awareness activities
including formal and informal education is considered as one of the mostimportant activities for Dien Bien city.
From the experiment, the findings indicated that the program carried out in urban
city with children and adult participation was effective. Children at age 10 to 12
years-olds can learn earthquake mitigation and can transfer earthquake knowledge
to their family members. Parent in urban city improved earthquake knowledge
through learning from their children without effect of age, education and gender.
In other words, the approach raising earthquake awareness for citizens throughchildren education is effective.
The results of social concern survey in Dien Bien city showed that, local people
are worry most disaster and income following these are other problems likedisease and road accidents. Among disasters happened in city, earthquake is themost concern of citizens. People have experienced earthquake in the past
recognized the importance of earthquake education while those who don’t haveearthquake experience neglect that. The research found out that, the more local
people having earthquake experienced getting older, having higher education, themore they need earthquake education. This survey also presented the limitation ofdisaster information sources in the city. Among number of information sources
such as, TV, Internet, Newspaper, radio, Television is the most popular for them.

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REFERENCES
Andrew Coburn, Robin Spence. (1992). Earthquake protection. New York: John
Wiley & Sons.
Anh, D. N. (2010). Seismic Hazard of Territory of Viet Nam. Hanoi, Ha Noi, Viet
Nam.
CSEP. (2011). Independent Expert Panel on New Madrid Seismic Zone
Earthquake Hazards. New York: USGS.
Dinh, X. N. (1993). Vietnam systemartic strategy is begining to take shape.
Seismic Risk Management for Countries of the Asia Pacific Region (p. 167).
Bangkok, Thailand: WSSI (World Seismic Safety Initiative).
Gulay, H. (2010). An earthquake education program with parent participation forpreschool children . Educational Research and Review , 624.
Izadkhah, Y. O. (2005). Toward resilient communities in developing countries
through education of children for disaster preparedness. Int. J. Emergency
Management , 138.
Kirschvink, Joseph L. (2000). Earthquake Prediction by Animals. Evolution andSensory Perception , 312-323.
Parsizadeh, F. (2007). School Earthquake Safety education Present and Future.
First global Platform Intergrated Disaster Risk Management. Geneva: United
Nations.
Pelling, M. (2010). Review and Systematization of Disaster Preparedness
Experiences in Urban Areas in the Caribbean Region. German: Oxfam.
Phuong, N. H. (2011). Eartquake - Tsunami assessment and Risk mitigation in
Vietnam using GIS. Hanoi, Hanoi, Vietnam.
Phuong, N. H. (2012). Seismic Hazard Studies in Vietnam. GEM semi- anual
meeting. Taipei, Taiwan: Institude of Geophysic.
Wisner, B. (2006). Let Our Children Teach Us. Bangalore, India: Book for
Change.
Shiwaku, K. (2007). Disaster Education in Japan and Nepal. Kyoto, Kyoto, Japan.
Wisner, B. (2006). Let Our Children Teach Us. In Let Our Children Teach Us (p.
2). India: Books for Change
Zobel, T. (1992). Intergrating Earthquake Education Into the Elementary School
Curriculum: A Whole Language Approach. Buffalo: National Center for
Earthquake Engineering Research

Increasingawareness
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through riskchildreneducation:
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Public housing after hurricane: Urban
renewal or removal? The case study of
Beaumont and Galveston, Texas, U.S.A.
Tho TRAN1, Shannon VAN ZANDT2, and Walter G. PEACOCK31
PhD Student in Urban and Regional Sciences,
Department of Landscape Architecture and Urban Planning,
Texas A&M University, United States of America
ductho2211@neo.tamu.edu
2
Associate Professor, Director of Center for Housing and Urban Development,
Texas A&M University, United States of America
3
Professor, Director of the Hazard Reduction and Recovery Center,
Texas A&M University, United States of America
ABSTRACT
Decent housing is a goal for many people not only in the United States but
elsewhere in the world. A house becomes the symbol of family spirit whether it isa single-family or multiple-family home. Public housing in the United States ishousing of “last resort,” for families whose incomes do not allow them to findhousing in the private market. Yet, many studies focusing on public housing finda host of social issues plaguing these units. The US Government has initiatedvarious programs to improve the quality of public housing as well as the living
condition of local resident through agenda of Department of Housing and Urban
Development (HUD). HOPE VI is one of the major programs that focuses on
distressed public housing. This program funds local government and housing
authority in order to revitalized or rebuild public housing. This program has beenvery successful in providing high-quality housing for public housing residents.
However, as any type of construction, housing usually received great damage
when natural disaster happening. It can be partly damaged or completely
destroyed due to the direct and indirect effects of disaster. Public housing, likemost affordable housing, is often built in highly vulnerable areas, such as
floodplains or other low-lying areas. When disasters such as hurricanes strike,housing located in these areas is likely to receive the greatest damage andrecovery may be slower.
This study looks at the case study of public housing in Galveston and Beaumont
after Hurricane Ike (2008) and Rita (2005). After Hurricane Rita in 2005,
Beaumont has rebuilt some public housing developments with a HOPE VI grantawarded in 2007. These areas have successfully rebuilt through the cooperationof housing authority, local government, local residents, and developers. In
contrast, Galveston could not reach agreement about the destiny of public
housing after Hurricane Ike in 2008. This story becomes more serious when HUD
announced that if Galveston cannot rebuild public housing in disaster area, theymust refund the money to the Federal Government. These two cities provide a467

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamcomparative case study of the response and recovery of public housing after
disaster, where on one successfully rebuilt while other did not.
By looking at the secondary data sources, this research analyzes the situation ofthese places in different period: before the Hurricane, when the Hurricane
happened, and after the Hurricane. The paper will address the similarities as well
as differences between two case studies in term of historical profile, demography,
public housing program characteristics, damage, and recovery. Besides,
economic change after hurricane approached is addressed. The housing situation
will be further analyzed in Galveston to clearly show the obstacles in which thiscity coped with. Finally, the study will conclude by suggesting some implications
for theory, housing policy, management, and further research.
Keywords: public housing, affordable housing, hazard management, response,
recovery, hurricane, United States, Galveston, Beaumont, Texas.
1. INTRODUCTION
Decent housing is a goal of every family in the United States as well as elsewherein the world. It can be appeared with different styles and layouts such as singlefamily home or multiple-family complex. After World War II, US government
has released different Housing Acts through periods with the general purpose ofbringing more housing opportunities for people. As one part of the working
agenda, public housing had been placed as the center of social concentration. This
type of social housings play important role in dealing with housing necessary of
distressed families who are unable to purchase a house according to the private
market. Public housing receives different support from the Federal government aswell as agencies. There are several programs that greatly contributed to thedevelopment of public housing in the US such as Section 8, Community
Development Block Grants (CDBG), HOPE VI, among others. Each program has
their own features as well as requirements and supported objectives due to their
mission. However, HOPE VI is a special program that is designed to support
community to recovery after natural disaster such as hurricane, flooding, or
earthquake.
Located in the large continent, the US has to face different types of natural
disaster. Hurricane appears as one of the major threats that directly affect humanlife because of it devastated effects. Like other construction’s elements during thecatastrophe, housing is vulnerable coping with the anger of nature. They are easily
wiped out as well as destroyed partly or entirely due to the level of the hurricane.
When it happen, public housing received more negative impacts due to its larger
number of resident in compare with single family construction.
Based on the United States natural disaster risk map, Texas Gulf Coast is an area
where hurricane visit frequently every year. Many coastal cities have been
affected by the activities of hurricanes in the area. From those, Galveston and
Beaumont are two places sharing the unhappy experiences with natural disaster.
In 2005, hurricane Rita visited City of Beaumont on the way approaching Gulf
Coast areas of the US. Rita had an impact on large area within multiple states
including Florida, Louisiana, Mississippi, and Texas. According to the report,

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25% of the trees in the city of Beaumont were uprooted by the hurricane.
Together with that damage, an enormous number of houses and business had
suffered damage by heavy wind as well as falling trees and debris in the air. Someareas did not have power for more than a month due to serious damage to city
infrastructure.
Galveston is an barrier island on the south of Texas state. The City of Galveston is
one of the high frequency place that hurricane approach each year in the US. In
fall 2008, the major hurricane in the season namely Ike had visited Galveston.
This hurricane last for more than a week and make huge damage for the City ofGalveston. Hurricane Ike hit Galveston Island and damaged about 88% of theresidential units. While the majority had minor damage, approximately 1,000
were substantially damaged. At that time, Galveston Housing Authority (GHA)
was managing 990 units of public housing, including 356 units in two high rises
for the elderly, 34 scattered sites, 20 new duplexes for the elderly, and 569 family
units. According to the GHA’s report, more than half of public housing stock wasdamaged beyond repair by the hurricane. Ike became the costliest hurricane in
Texas history with the total damage approximately reach $29.5 billion dollars.
2. RESEARCH QUESTIONSBoth cities had received huge damages after storms left. There remains many
works and efforts needed in order to bring normal life back to local areas. Besides
all of the recovery processes, housing rebuild and recovery plays fundamental rolethat directly affect the residential and their family. This research focuses on therecovery issues of public housing where vulnerable population was waiting forexternal supports.
Housing recovery after hurricane is an inevitable part of revitalization process
after disaster events. However, what happen in each place is different due toparticular characteristics. Moreover, some processes happen with reverse direction
with others. Those are the case of public housing after hurricane in Beaumont andGalveston, Texas. They share the same situation of being damage by devastatedhurricanes. Housing stock in both cities has received negatively affected by storm
while the shortage of affordable housing was their temporary problem. And, theyboth work in recovery process in order to rebuild public housing for low income
people. However, the results of their efforts are totally different. Beaumont has
rebuilt some public housing development with a HOPE VI grant awarded in 2007.
These areas have successfully rebuilt through the cooperation of housing authority,
local government, local residents, and developers. While Beaumont has a
successful revitalization program with public housing after hurricane Rita,
Galveston stuck in a debate about public housing’s redevelopment plan. Housing
authority in Galveston tried to create the most appropriate redevelopment plan for
public housing while local community and some conservative city councilmen
opposed bringing public housing back to the island. This story becomes more
serious when Department of Housing and Urban Development (HUD) announced
that if Galveston cannot rebuild public housing in disaster area, they must returnthe funding to the federal Government. These two cities provide a comparative
case study of the rebuilding of public housing after disaster, where on one
successfully rebuilt while other did not.
PublicafterUrban
hurricane:Urban
renewal or removal? The case study of Beaumont
Public housing
afterhousing
hurricane:renewalor removal?
andGalveston,
Texas,U.S.A.
The case study of Beaumont and Galveston,Texas, U.S.A.

469

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamThere are some questions have been raised through the study of both cities. Firstly,
the overall change of demography in entire two cities is expected to find bylooking at the data before and after hurricane. Secondly, the process of rebuilding
public housing in each city might suggest the reason leading to redevelopment
plan. In addition, by looking at closely at public housing area through various
topics and data set, the author hopes to find quantitative evidences that support towhat happen in both cities. The latter part of this paper will indicate two casestudies with population data set in order to find the responses for above concerns.
3. METHODOLOGY
By looking at the secondary data sources, this research will address thesimilarities as well as differences between two case studies in term of demography,
public housing program characteristics, damage, and recovery. Besides, economicchange after hurricane approached is addressed. The housing situation will befurther analyzed in Galveston to clearly show the obstacles in which this city
coped with. Finally, the study will conclude by suggesting some implications fortheory, housing policy, management, and further research.
3.1 Public Housing Areas Analysis
In order to observe the general picture in public housing areas as well as theirfluctuations between 2000 and 2010, this study conducts equivalent analysis in a
local level in terms of age groups, race, and housing characteristics. Gaining
access to the location of each public housing development enables the author to
precisely indicate in which block groups public housings were located. Then,census data for block group level in each city is accessed through U.S. Census
Bureau web site. By adding up data of all block groups that contain public
housing developments, the author analyzes basic trend as well as alteration ofeach topic in public housing areas from 2000 to 2010.
3.1.1

Races

Table 1 shows race data in public housing area in Beaumont. The Not Hispanic
Black people took the largest share in total public housing population. In 2000,
there were 5,900 people accounted for 70% people living there were Not Hispanic
Black. This number increased to 6,107 people, equivalently to 73% of total
population in 2010. Furthermore, Not Hispanic White is clearly perceived to be
the group bearing the largest drop in in public housing population over this period.
In 2010, they declined 607 people equivalent to 34.5% of their population in
public housing neighborhood in 2000. In other hand, Galveston race has beenshown some changes according to the Table 2. In contrast with Beaumont, Not
Hispanic White in Galveston increased in this period from 963 people to 1,579
people while Not Hispanic Black decreased about 540 people represented 22% of
their population in 2000. Although Not Hispanic Black remained the mostpopulated group living in public housing, each city shows reverse direction ofchanging. While public housing areas in Beaumont increased from 70% to 74%,
Galveston greatly decreased from 53% to 38% of total population living in public
housing areas.

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Table 1. Race in Public Housing Areas in Beaumont, TX
BEAUMONT, TX

Population 2000
Count Share
1,760 21.02%
5,900 70.48%
230
2.75%
481
5.75%
8,371 100%

Not Hispanic White
Not Hispanic BlackNot Hispanic Others
Hispanic or Latino
Total Population:

Data Source: Census Bureau 2000, 2010

Population 2010
Count Share
1,153 13.90%
6,107 73.63%
190
2.29%
844
10.18%
8,294 100%

Population Change
Share
Count
-607
-34.5%
207
3.5%-40-17.4%
363
75.5%
(X)
(X)

Table 2. Race in Public Housing Areas in Galveston, TX
GALVESTON, TX

Population 2000
Count Share963
20.69%
2,459 52.84%
71
1.53%
1,161 24.95%
4,654 100%

Not Hispanic White
Not Hispanic BlackNot Hispanic Others
Hispanic or Latino
Total Population:

Data Source: Census Bureau 2000, 2010

Population 2010
Count Share
1,579 30.97%
1,919 37.63%
160
3.14%
1,441 28.26%
5,099 100%

Population Change
Share
Count
616
-540
89
280
(X)

64.0%
-22.0%
125.4%
24.1%(X)

3.1.2 Housing Units
Table 3 and Table 4 show statistical data of housing characteristics in public
housing in Beaumont and Galveston, TX. According to the data set, the number ofowner occupied units in public housing areas of Beaumont reduced by 122 units
from 1,511 in 2000 to 1,389 in 2010. At the same time, the renter occupied unitgroup only saw an increase of 25 units, which equaled to 1.5% of total rental
occupied units in public housing area in 2000. More importantly, while thenumber of vacant units in Beaumont increased 145 units, the equivalent amount in
Galveston was 520, approximately 136% of total vacant units in 2000 in public
housing areas. Through Exhibit 6, a dramatically change in housing stock in
Galveston has been depicted. Renter occupied unit dropped from 62% in 2000 to
45% in 2010 while vacant units increased from 16% to 34%. In Beaumont, there
were stable trends except for a slight reduction in the number of owner occupied
units.
Table 3. Housing Characteristics in Public Housing Areas in Beaumont, TX
BEAUMONT, TX
Owner Occupied
Renter Occupied
Vacant
Total

Units 2000
Count
1,511
1,650
317
3,478

Units 2010
Count
43.4% 1,389
47.4% 1,675
9.1%
462
100.0% 3,526

Share

Data Source: Census Bureau 2000, 2010

Share
39.4%
47.5%
13.1%
100.0%

Change
Share
Count
-122
-8.1%
25
1.5%
145
45.7%
(X)
(X)

PublicafterUrban
hurricane:Urban
renewal or removal? The case study of Beaumont
Public housing
afterhousing
hurricane:renewalor removal?
andGalveston,
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Table 4. Housing Characteristics in Public Housing Areas in Galveston, TX
GALVESTON, TX
Owner Occupied
Renter Occupied
Vacant
Total

Units 2000
Count
516
1,489
382
2,387

Data Source: Census Bureau 2000, 2010

Share
21.6%
62.4%
16.0%
100%

Units 2010
Count
572
1,186
902
2,660

Share
21.5%
44.6%
33.9%
100%

Change
Share
Count
56
10.9%
-303
-20.3%
520
136.1%(X)(X)

3.2 Economic Analysis in Two Cities before and after Hurricanes
3.2.1

Job Earning Analysis

Table 5 and Table 6 show the statistical data about jobs respectively in 2004 and2006, in Beaumont and Galveston. The category includes different monthly
earning jobs such as low wage job, moderate wage job, and high wage job. In
Beaumont, all of job categories increased from 2004 to 2006 with a total of about
4,047 jobs. Overall, high wage job experienced the fastest enhancement with morethan 2,000 newly increased jobs while low and moderate-wage job shared thesame improvement of more than 900 ones. Galveston experienced a different
scenario after Hurricane Ike in 2008. Before that, moderate wage job group had
the largest share with 40.9% while low wage job compromised only 27% of total
jobs in Galveston in 2007. While both of these job groups reduced in 2009, highwage job slightly increased with 115 jobs equally 1.5% of total jobs in 2007. Low
wage jobs in Galveston experienced a great lose after Hurricane Ike with morethan 1,600 jobs. This reduction equals one quarter of low wage jobs in Galveston
at the time of 2007. This decrease suggested the effect of Hurricane Ike as well as
its damage towards the low income group in Galveston.
Table 5. Jobs in Beaumont, TX Before and After Hurricane Rita (2005)
BEAUMONT, TX
Jobs by Earnings$1,250 per month or less
$1,251 to $3,333 per monthMore than $3,333 per month
Total

2004
Count Share
14,863 32.2%
18,885 40.8%
12,465 27.0%
46,213 100%

2006
Count Share
15,783 31.4%
19,871 39.5%
14,606 29.1%
50,260 100%

Change after
Hurricane Rita (2005)
Count
Share
6.2%
920
5.2%
986
17.2%
2,141
4,047
(X)

Data Source: U.S. Census Bureau, OnTheMap Application at onthemap.ces.census.gov

Table 6. Jobs in Galveston, TX Before and After Hurricane Ike (2008)
GALVESTON, TX
Jobs by Earnings$1,250 per month or less
$1,251 to $3,333 per monthMore than $3,333 per month
Total

2007
Count Share
6,302
27.0%
9,557
40.9%
7,482
32.1%
23,341 100%

2009
Count Share
4,682
23.0%
8,098
39.7%
7,597
37.3%
20,377 100%

Change after
Hurricane Ike (2008)
Count
Share
-25.7%-1,620-15.3%-1,4591.5%
115-2,964(X)

Data Source: U.S. Census Bureau, OnTheMap Application at onthemap.ces.census.gov

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3.2.2

Inflow – Outflow Analysis

One of the important features of economic flow analysis is the natural of
movement in population in term of joining economic activities. Table 7 and Table
8 show the inflow and outflow of labor force in Beaumont and Galveston before
and after disaster events. In Beaumont, the number of people living and working
inside the city increased from 27,453 in 2004 to 29,768 in 2006. Thisphenomenon can be considered as an advantage of redevelopment projects thattook place in Beaumont after Hurricane Rita. Clearly, it shows the advantage ofurban renewal trend in this area where people can work and live inside the city.
Together with the general trend of economic improvement, the number of people
working in Beaumont but living outside greatly increased by 7,230 people,
equally to 18.1% of the population before Hurricane Rita. Conversely, the numberof Beaumont residents working outside marginally increased with approximately
1,732 people from 2004 to 2006.
Galveston shows a totally opposite trend in term of economic movements of thearea. The number of people who lived and worked in Galveston declined morethan 3,300, or more than a quarter of the previous figure obtained in 2007 before
Ike. This trend might as well relate to the previous analysis of the decline in the
low wage jobs in Galveston. More importantly, the author believes the issues of
housing redevelopment processes greatly attributed to this trend in the Galveston
area. In addition, the number of people working in Galveston but living outside as
well as people living in Galveston but working outside both shared some minorchanges. While the former group decreased by 725 people, the latter groupincreased by about 357 residents. These changes only equaled to 3.9% and 3.3%of total numbers in the same groups before Hurricane Ike approached Galveston.
Table 7. Work Movement Before and After Hurricane Rita (2005)

Employed in Beaumont
Living in Beaumont
Living Outside

2004
Count
Share
67,366 100%
27,453 40.8%
39,913 59.2%

2006
Count
Share
76,911 100%
29,768 38.7%
47,143 61.3%

Change after
Hurricane Rita (2005)
Count
Share
(X)
9,545
8.4%
2,315
18.1%
7,230

Living in the Beaumont
Employed in Beaumont
Employed Outside

46,21327,45318,76050,26029,76820,492

4,047
2,315
1,732

BEAUMONT, TX

100%
59.4%
40.6%

100%
59.2%
40.8%

Data Source: U.S. Census Bureau, OnTheMap Application at onthemap.ces.census.gov

(X)
8.4%
9.2%

PublicafterUrban
hurricane:Urban
renewal or removal? The case study of Beaumont
Public housing
afterhousing
hurricane:renewalor removal?
andGalveston,
Texas,U.S.A.
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Table 8. Work Movement Before and After Hurricane Ike (2008)

Employed in Galveston
Living in Galveston
Living Outside

2007
Count Share
30,853 100%
12,416 40.2%
18,437 59.8%

2009
Count
Share
26,807 100%
9,095
33.9%
17,712 66.1%

Change after
Hurricane Ike (2008)
Count
Share
(X)
-4,046-26.7%-3,321-3.9%-725

Living in Galveston
Employed in Galveston
Employed Outside

23,341
12,416
10,925

20,377
9,095
11,282-2,964-3,321357

GALVESTON, TX

100%
53.2%
46.8%

100%
44.6%
55.4%

Data Source: U.S. Census Bureau, OnTheMap Application at onthemap.ces.census.gov(X)-26.7%
3.3%

3.3 Discussion
Natural disaster is unexpected event happening out of human control. However,with nowadays technology, we are able to predict as well as proactive withpreparations in order to minimize the damage caused by natural disasters. Oncethey happen, the process of recovery plays a critical role in bringing people backto normal life. What happened in Beaumont and Galveston are regarded as twointeresting stories. Both cities suffered from severe damages caused by some of
the most devastated hurricanes in Texas history. Beaumont was not hit directly by
Hurricane Katrina or Hurricane Rita as Galveston was, in the situation of
Hurricane Ike. The impacts levels that hurricanes affected both cities varied
according to their own features and their reactions to the events.
Beaumont was really an opportunity-catcher when wisely dealing with thesituation of the city especially housing stock after Hurricane Rita dissipated.
Although the public housing areas in Beaumont did not experience as hugedamages as Galveston did, Beaumont still planned to rebuild the old public
housing areas based on the nature of recovery processes after the disaster. Thechanges that Beaumont brought to ground for public housing areas as well assurrounding communities are considered as one of the most successful urban
renewal achievements. They did not only achieve the goal of recovery after
disaster but also turned this opportunity into a great catalyst for housingdevelopment. The success of Beaumont Public Housing redevelopment camefrom different elements. They had a clear plan with careful preparation, strongly
support from the city as well as residents and most importantly, a great housing
authority that understood the situation and knew how to realize the goal withflexible strategies as well as passionate willingness. This strong factor turned thehurricane into an opportunity for urban renewal that supported mixed-income
developments.
Conversely, Galveston experienced a more depressing situation after Hurricane
Ike. What happened in Galveston distressed every element of the whole
redevelopment efforts. First and foremost, the public housing residents were themost distressed subjects since they lost everything because of the natural disaster.
Many of them became the victims of hurricane damages which negatively
affected their life, work, and properties. More seriously, they were unable to comeback to their places because of others’ opinions. This clearly was not fair with themost vulnerable group in population. In addition, what happened in Galveston

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after Hurricane Ike also affected local resident who were not public housing
dweller. They had to spend their time and efforts in order to protect their opinions
toward redevelopment of public housing. The author believes that many of themhad to work extra hours as well as spend additional money for their debating.
Besides the public housing resident group, the public authority was affected by
the hurricane as well. These effects stand out-side the normal curriculum of
recovery process. They are in the middle of two sides who shared reverse opinions
towards public housing redevelopment after hurricane. These conflicts factored tothe public authority’s delay in recovery work. It not only affected the victims ofhurricane but also the city in general since public works had been postponed due
to deferred decisions. Last but not least, federal programs are another element thathas been negatively affected by Hurricane Ike. They are forced to become
involved in the debated of public housing in Galveston. In order to pursue thegeneral goals of affordable housing and social equity, public programs needed tointervene with this debate. Clearly, if the problem had not been existed, theredevelopment processes would increase economic development as well as bring
improvement for the island. One strong example is the case study of Beaumont,
Texas. Therefore, Hurricane Ike was not only costly with regards to its damage on
physical properties but also socially distressed for every side of the recovery
processes.
3.4 Policy Implication
Beaumont and Galveston are two strong examples of the policy implication
process. In Beaumont, the key of successfully redeveloping public housing after
hurricane is the cooperation between each participant of recovery processes.
Beaumont Housing Authority plays a crucial role in this collaboration. They
reacted to the situation with adequate preparation as well as creative responses
within their power. The damage of Beaumont did not get enough attention offederal agencies as it should because of the overwhelming attention drawn to New
Orleans after Katrina. BHA was proactive in their responsibility in order to recall
the support from federal agencies through many necessary actions by different
groups. In addition, they took a wise move when collaborating with academic
scholars and students from Department of Landscape Architecture and Urban
Planning, Texas A&M University. This cooperation helped BHA effectively
develop a comprehensive neighborhood revitalization plan to spur investment andredevelopment in public housing neighborhood. In addition, besides theinnovation in financial solutions, BHA also developed an effective management
mechanism that supported housing development. The public – private partnershipalso prove the successful result in supporting residents by abundant service fromdaily needs to professional skills as well as necessary consultancies.
In contrast, Galveston faced many issues related to policy implementation. Aftersuffering from devastated damage from Hurricane Ike, Galveston could haveaccomplished this opportunity to redevelop housing stock and improve the spillover effects of these developments as part of the urban renewal process. However,the cooperation between Galveston Housing Authority and City government
proved an unsuccessful relationship when GHA could not get the support fromresidents as well as public authority despite of their great efforts. GHA is an
example of housing authority who acts as a bridge that connects residents, public
PublicafterUrban
hurricane:Urban
renewal or removal? The case study of Beaumont
Public housing
afterhousing
hurricane:renewalor removal?
andGalveston,
Texas,U.S.A.
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negatively affected every party of this triangle. Therefore, Galveston could well
be considered an example of ineffective policy implementation in relationshipwith housing recovery in post-disaster.
3.5 Practical Recommendations
Recommendation #1: Housing Authority should be more proactive with
substantial preparations and innovative solutions.
Recommendation #2: Housing for low income population needs to be developedin mixed-income community in order to support the individual as well as family
improvement.
Recommendation #3: Public-private partnership should be executed in any stepsof the development as long as it shares the same goal of supporting community.
Recommendation #4: Collaboration between housing authority and academic
experts or professional firms should be accessed as an effective way to conduct
successful development for new project.
REFERENCES
Peacock, W. G., Zhang, Y. and Dash, N. 2005. Single Family Housing Recovery
after Hurricane Andrew in Miami-Dade County. College Station, TX:
Hazard Reduction & Recovery Center, Texas A&M University.
Schwartz, Alex F. 2010. Housing Policy in the United States. Second Edition.
Routledge, New York
Van Zandt, Shannon, Edward Tarlton, June Martin, Dawn Jourdan, and Cecilia
Giusti. 2012. Magnolia Garden HOPE VI Evaluation. College Station, TX:
Center of Housing and Urban Development, Texas A&M University.
United States Census Bureau website: www.census.gov

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Flood adaptive cities
towards climate change adaption
and urban development in Mekong Delta
Thu Trang LE
Lecturer, Faculty of Architecture and Urban Planning,
National University of Civil Engineering, Vietnam
Graduate student, Department of Urbanism,
Faculty of Architecture, Delft University of Technology, Netherlands
trangb16186@yahoo.com

ABSTRACTDeltas are the magnetic regions to inhabit for half of the world’s population
because of their rich natural resources and strong economic potentials for
agriculture, aquaculture, tourism, and port development (UN-Habitat, 2006).
However, frequent floods, salt-water instruction, and freshwater scarcity arecommon challenges that put a large number of people living in the deltas at risks.
The Mekong Delta is considered as one of the largest delta in the world where ishome for more seventeen millions people concentrating along the watercourses ofrivers and canals. For a long time, local communities have traditionally adapted
their lives to the presence of water. In the recent decades, water however has nolonger plays the important roles in the social, economic and cultural activities of
the citizens. As consequences of economic development and urban expansion,waterways have been replaced by roads and space for water in the delta-cities
have been diminished. The city is losing its unique characteristic and inhabitants
are facing more vulnerable to flooding. Therefore, finding innovative solutions toadapt to floods is crucial, especially in times of climate change. A new strategy is
not only solely relying on technology of flood-defense but also has to combine
water management with the urban development.
By using “Layer approach”, this paper firstly determines the current problems of
the Mekong Delta. Secondly, relevant strategies that can be visible the interaction
between climate change adaption, water management and urban development of
the Dutch delta are reviewed. Finally, the paper explores the possibility to apply
these strategies in a case study of the Mekong Delta. We strongly argue that theseflooding adaptive solutions can be useful for other delta-cities worldwide.
Keywords: climate change, integrated strategy, water management, urban
development, flood adaptive cities, the Mekong Delta

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1. INTRODUCTION
Deltas, where river flows into the sea, ocean, lake or reservoir, are the magnetic
areas to inhabit for half of the world’s population and also half of the world’s
urbanized areas (UN-Habitat, 2006) because of the most fertile land for
agriculture and the most strategic locations for industrialization and urban
development. Living close to the waterfront is now attracting a new stream of
inhabitants, tourists, services and business to the cities. Since most of the large
cities are located in delta region, an unintended side effect of the growth and theensuing concentration of population is the increased challenge. The changing
global climate recently puts additional pressure on this challenging situation.
How people deal with sea level rise, with erosion, with salinity intrusion, withsubsidence and drought, and with the interactions between climate and urban
areas?
Accommodating this question will involve the development of hydraulicinfrastructure, such as: flood defenses, land reclamation, etc. In the Netherlands,
answering this question is matter of survival. For a thousand year, the inhabitants
built dikes to protect themselves and their properties against floods. After thedevastating storm surge in 1953, Delta Works were created to keep the North Sea
out of the estuaries and tidal inlets using dams, sluices and storm surge barriers(Delta program, 2012). The protection practices continue until the present day
situation, however, the relation between Dutch people and water has changed:‘The main characteristics of the delta landscape in the past were the dynamicchanges in water tables, the erratic and uncontrolled flooding and seepage andthe vast, inaccessible stretches of low-lying land during winter inundations… This
image has completely changed. Nowadays land is land, and water is water…
Erratic changes in water tables are not allowed anymore’ (Nienhuis, 2008).
Traditional approaches focus exclusively on the primary function: protection
against flooding might not be efficient in the new challenge situation.
In the Mekong Delta region, people in the delta consider water dangers to benormal phenomenon and have generally adapted their lives to their presence. Thus,
countries such as China, Vietnam and Thailand are known as some of the world’s
biggest exporters of rice (USDA, 2011). For hundred years, the water system
including natural and manmade canals used for agriculture, irrigation, watertransportation and military has been a foundation for other systems to be laid on(Shannon, 2009). However, in the last decades, as the rapid expansion of urban
areas, road has replaced water to become the main economic, social and cultural
life of the delta (Tayler, 2006). The canals are filled up and many flood plains are
removed. Delta cities in this region are now separating from water and facing
additional threats.
Therefore, sustainable development is crucial in deltas all over the world. This is
not solely relying on technical solutions to fight against and control the delta
environment, but a new approach that utilizes natural processes for water safety
and sustainability for both the delta and its inhabitants. This approach is targeted478

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at different disciplines: hydraulic engineering, urbanism and landscapearchitecture. Although there already exists a large body of knowledge on thecharacteristics and functioning of many deltas, most of this information is of amono-disciplinary. There is relatively little knowledge that enables an overview
of delta management in which these disciplines would be integrated. By using“Layer approach”, this paper firstly determines the current problems of the
Mekong Delta. Secondly, relevant strategies that can be visible the interaction
between climate change adaption, water management and urban development of
the Dutch delta are reviewed. Finally, the paper investigates the possibility toapply these strategies in a case study of the Mekong Delta.

2. LAYER APPROACH
Urbanized river deltas demonstrate different characteristics depending on theirlocal climate, geographical condition, economic and political circumstances.
Therefore not all deltas can easily be compared to other deltas. But many deltas
have developed along the same patterns and have experienced the same problems
as other deltas did at the same phase in their development. Delta cities all over theworld, such as: New York, Rotterdam, Ho Chi Minh city, are the result of a longtime interrelation between the nature and urban system. The natural complexity ofthe deltas, as the meeting of rivers and sea, with the complexity of urban pattern,
as result of economic, cultural and social life creates unique areas with a double
complexity (Meyer, 2009). Between these systems, infrastructure including
waterways and roads play the key role in creating conditions for the developmentof the urban systems and influencing the nature system.
To provide insight in these complex systems, it is proposed to apply a simplified
structure in the form of a “Layer model” (Figure 1) that is a component of threelayers: the natural landscape (base layer), the infrastructural/ network layer(middle-layer) and the occupation layer (top-layer). This approach firstly was
introduced by Ferdinand von Richthofen (1833-1905) to describe the chorologicaland topological relationships in the landscape. In the late sixties, Ian McHarg, alandscape architect, applied and developed it into ‘layer cake model’ for reasonsof spatial analysis and planning in his seminal work: Design with Nature (McHarg,
1969). Recently, “Triple 3 layers approach”, a more comprehensive planning anddesign oriented approach towards urban delta landscapes, was introduced by
Meyer and Nijhuis (2010). This ‘Layer model’ presents a physical hierarchy in thesense that the layers enable and/ or constrain activities in another layer.

Flood adaptive
citiestowards
climatechangeadaption
andadaption
urban developmentin Mekong Delta
Floodadaptive
citiestowards
climatechangeand urban development......

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3. MEKONG DELTA AND ITS FORMATIVE LAYERS
3.1 Overview of the Mekong Delta
The Mekong River is the 7th longest river in Asia and 12th longest river in theworld. Its estimated length is 4,350 km (2,703 mi), and it drains an area of
795,000 km2 (307,000 sq mi), discharging 475 km3 (114 cu mi) of water annually(MRC, 2010). Mekong River as the hydrological backbone of its basin travels
4200 km from its headwaters in the Tibetan plateau to China, Myanmar, Thailand,Laos, Cambodia and to its delta in Vietnam. The complexity of Mekong delta is
ecologically shaped by water of the Mekong River, monsoon climate and tide of
the South China Sea (Hans Dieter, E. and Simom, B, 2009). Annually, MekongRiver carries 16 million tons of sediment. This sediment transport has created a
fertile soil for agriculture production that provides food for approximately 60
million people living in riparian countries (Pham, 2011).
The Mekong River Delta, one of the largest deltas in the world, was formed by thedeposition of sediments transported from the Mekong. Mekong delta is defined asa vast triangle plain, beginning at the downstream of Phnom Penh (Cambodia)(Pham, 2011). For two third the Mekong delta is situated in southern Vietnam andfor one third in Cambodia. It is one of the most productive and intensively
cultivated areas in Vietnam (known as ‘Rice basket’) and a priority area for
economic development (Bucx, T., Marchand, M., Makaske, A., Van de Guchte, C.,2010). The Mekong Delta is a wave- and tide-dominated delta; as a result of
meeting of the two branches of the Mekong River.
3.2 Natural landscapeMekong Delta or “Cuu Long” Delta (“Cuu Long” refers to “Nine Dragon” inVietnamese) is the region in south-western Vietnam where the Mekong River480

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approaches
approaches
and andempties
empties
intointo
the thesea seathroughthrougha networka networkof nineof nineestuaries.
estuaries.
TheThenaturalnaturalprocesses
processesof erosionof erosion
and andsedimentation
sedimentation
processes,
processes,
which
which
are areinfluenced
influenced
by by
sea seacurrent
current
fromfrom
bothboththe the
South
South
China
China
Sea Sea
and and
GulfGulfof Thailandof Thailand
and andannualannualflood
flood
condition,
condition,
formformcomplexity
complexityof theof thedelta.
delta.
A variety
A varietyof deltaof delta
landscapelandscapeis displayed
is displayedin thisin thisregion:region:riverriverlandscape,landscape,floodplain
floodplain
and andcoastalcoastallandscape.
landscape.
Each
Each
of theseof thesenaturalnaturallandscapes
landscapes
is bestis bestsuitedsuitedfor fordifferent
different
landlanduses,uses,
suchsuch
as: as:agriculture,
agriculture,
recreation
recreation
and andurbanization.
urbanization.
3.3 3.3
Formation
Formationof infrastructureof infrastructure
andandoccupation
occupation
layer
layer
Urbanization
Urbanizationis theis thesecondsecondstepstep
forming
formingdeltadeltalandscapes.
landscapes.
‘Building‘Buildingdeltaic
deltaic
citiescitiesin ainmannera mannerthatthataccommodates
accommodates
seasonal
seasonal
flooding
flooding
by primarily
by primarily
urbanizing
urbanizing
higherhighernaturalnaturallevees,levees,leavingleaving
low-lying
low-lyingswampsswampsandandmarshesmarshes
undeveloped
undeveloped
to storeto storewater,
water,
andandstrategicallystrategically
perforating
perforating
riverfront
riverfront
leveesleveesbalancesbalances
urban
urban
requirements
requirements
withwithdeltaic
deltaic
processes’
processes’(Campanella,(Campanella,2010).
2010).
TheTheMekongMekongDelta
Delta
has hasonlyonly
beenbeen
occupied
occupiedby theby theVietnamese
Vietnamese
for for
about
about
three
three
centuries.
centuries.
Nevertheless,
Nevertheless,thisthis
short
short
historyhistory
has hasexperienced
experienced
a varietya varietyof changing
of changing
regimes,
regimes,
warfarewarfareand andrevolution
revolution(Figure(Figure2): 2):

TheTheHolocene
Holocene
Pre-colonial
Pre-colonial
periodperiod French
Frenchlandscapelandscapeperiodperiodcolonialcolonial
From
From
AmericanAmericanwarwarto topresent
present

FigureFigure2. Development
2. Developmentof urbanof urbanpatternpatternin thein Mekong
the Mekong
Delta
Delta

3.3.1
3.3.1
TheTheHolocene
Holocenelandscapelandscapeas aasfoundationa foundation
TheThehighhighterraces
terracesof Mekongof Mekongdeltadelta
is believed
is believed
to haveto haveformedformedas early
as early
as 1asmillion
1 million
years
years
ago ago(Gupta,(Gupta,2008).
2008).
TheThenaturalnaturalprocesses
processesof sedimentation,of sedimentation,changechangeof seaof sealevel,
level,
tidaltidal
and andcurrent
current
effects
effects
for approximately
for approximately
8000
8000
years
years
createdcreateddifferent
differentdeltadeltalandscapes
landscapesin thisin thisregionregion(Pham,(Pham,
2011).
2011).
AccordingAccordingto Milton
to Milton
Osborne,Osborne,a Southeast
a Southeast
Asian
Asian
historian,historian,
the delta
the delta
waswas‘a largely‘a largely
waterloggedwaterlogged
world
world
of blackof black
mudmudandandmangrovemangrovetrees,
trees,
borderedborderedby thickby thick
tropicaltropicalforests
forests
where
where
the landthe landroseroseaway
away
fromfrom
the flooded
the flooded
plain’.
plain’.

Flood adaptive
citiestowards
climatechangeadaption
andadaption
urban
in MekongFloodadaptive
citiestowards
climatechangeandurban
development
Flood
adaptive
citiestowards
climatechangeadaption
anddevelopment
urban
development. . . Delta.. .. .. . . .

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October
2013, 2013,
Hanoi,Hanoi,
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ridges and barrier beaches that offered dry and safe land for the first urban
settlements (Meyer, H.et al.2009).
3.3.2 Pre-colonial period-Nguyen dynasty (1802-1867): River city
The delta started to form its own landscape since the mid of 16th century when
Nguyen Lords introduced a policy of land reclamation and breaking fresh groundto create villages (Pham, 2011). A large amount of inhabitants from the north andcentre parts of Vietnam had come and reclaimed new lands. Therefore, the first
type of settlement was created: villages around high ground areas along rivers(natural levees) and watercourses where the fresh water could be collected and thesettlers could survive from flooding. At the same time, a system of canal andsmall ditches were built up for transportation and irrigation purposes. This process
played an important role in transforming the uncultivated area of the delta into afertile plain for wet paddy productions.
3.3.3 French colonial period: Canal city
The canalization process were introduced far later in the Mekong delta. Until the
19th century, canal systems were introduced and played a key role in thedevelopment of new urban form. Silt from digging these canals created highmanmade levees for settlements. In these cities, waterways as rivers and canals
were mainly transportation and goods exchanged routes. Moreover, they were also
used for irrigation, drainage and fresh water supply purposes. Aware of thechanging environment conditions, inhabitants in these cities developed adaptive
strategies, often called “shaking hand with floods”, that accepted rather than resist
the potential catastrophic risk (Miller, 2006). These strategies resulted in a typicaldelta image with stilt houses, boat houses, floating markets, three sided canoes
that are still visible in the current delta cities.
3.3.4 From American war to present: Cross-road city
Starting from the sixties, the system of land-based infrastructure and flood-control
became a national concern for economic development. Settlements and cities
developed at the meeting points of motor roads and waterways that are high anddry places in times of flooding. The road replaced the water as the domain of cityand played a role in the embellishment of the city (Pham, 2011).
After a long history, cities in Mekong delta have always adapted with the dynamicchanging environments. These adaptive processes resulted in different types ofdelta cities: river city, canal city and cross-road city.

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3.4 Problems
3.4 Problems
For three
For threehundredhundredyears,years,
the Mekong
the Mekong
DeltaDelta
has becomehas becomea watera watersocietysocietywhere
where
inhabitants
inhabitantsin thisin thisregionregiondeveloped
developed
adaptiveadaptivestrategies,
strategies,
oftenoften
calledcalled“shaking“shaking
handhandwith withfloods”,
floods”,
that acceptedthat accepted
ratherrather
than thanresistresist
the potential
the potential
catastrophic
catastrophic
risk risk(Miller,(Miller,2006).
2006).
OverOvertwentytwentyyearsyears
after after
the introduction
the introductionof “DOIof “DOI
MOI”
MOI”
policypolicy(innovation),(innovation),
MekongMekongdeltadeltain Vietnam
in Vietnam
has experienced
has experienced
significant
significant
expansion
expansionof ofcitiescities
and rapid
and rapid
growth
growthof population.
of population.
The Thewaterwater
citiescities
are transforming
are transforming
into into
the theroad roadcitiescities
in which
in whichthe role
the ofrole
water
of waterin theincity
the structure
city structureis goingis going
to betoneglected.
be neglected.
Thus,Thus,
the cities
the cities
are losing
are losing
its unique
its uniquecharacteristic
characteristic
and inhabitants
and inhabitants
are facing
are facing
moremorevulnerable
vulnerable
to flooding.
to flooding.
Furthermore,
Furthermore,
the consequences
the consequencesof humanof humaninterventions
interventions
into into
naturalnaturalprocess
process
havehavecausedcausedan essential
an essentialchangechangein thein natural
the naturallandscapelandscape(Meyer,(Meyer,H. andH. Nijhuis,and Nijhuis,S., 2011).
S., 2011).
The Thetransformationtransformation
fromfroma naturala natural
dynamic
dynamic
waterwater
systemsystemin which
in which
peoplepeopleadaptedadaptedto thetoforces
the forcesof natureof nature
into anintoinfrastructure
an infrastructure
systemsystemin which
in whichthe forces
the forcesof natureof nature
are attempted
are attempted
to betocontrolled,
be controlled,
turnsturns
out toout
beto bemoremore
problematic
problematic(Figure(Figure3). 3).

FigureFigure3. Human
3. Humaninterventions
interventionsin theinMekong
the Mekong
DeltaDelta
Finally,
Finally,
climateclimatechangechangewill havewill havea servea serve
impactimpacton theonnatural
the natural
systemsystemof theofdelta
the delta
and inandtheinlives
the livesof thoseof those
livinglivingin thesein theseareas,areas,
namely:namely:floodflood
events,events,stormstorm
surge,
surge,
waterwater
scarcity,scarcity,
subsidence
subsidence
and salinization.
and salinization.
3.5 Can
3.5 CanTho ThoCity CityCan CanTho Thocity city
is a issuitablea suitablecase caseto explore
to explore
becausebecauseof itsof experiences
its experiences
in in
urbanization
urbanizationand floodand flooddefensedefenseapplication.
application.
Can CanTho Thois theis fifth
the fifth
largestlargestcity cityin inVietnamVietnamand theandlargest
the largest
city iscity
Mekongis Mekongdelta.delta.
It is noted
It is noted
for itsfortypical
its typicalwaterwater
basedbasedlandscapelandscapewith withfloating
floating
markets,
markets,
ruralrural
canalscanalsand stilt
and stilt
houseshousesalongalongwaterways.
waterways.
The city
The iscity
locatedis locatedalongalong
the Southern
the Southernbenchesbenchesof Hauof HauRiver,
River,
the southern
the southernbranchbranchof Mekongof MekongRiver.
River.
BecauseBecauseof itsofadvantages,
its advantages,
Can Tho
Can isTho
striving
is striving
to becometo becomea citya cityof industry-trade-service
of industry-trade-service
and andhigh-techhigh-techagriculture.
agriculture.
The Thecity city
maintained
maintained
an anaverageaverage
GDPGDP
growth
growthrate rateof 16%of 16%
per yearper yearfor thefor 2006-2010
the 2006-2010
periods,
periods,
and andis is
expected
expected
to haveto havea GDP
a GDP
growth
growthrate ofrate17.1%of 17.1%
for thefor2011-2015
the 2011-2015
periodperiodand 18%and 18%for 2016-2020
for 2016-2020
period.
period.
On theOn otherthe otherhand,hand,
its population
its population
has increased
has increased
fromfrom
180,000
180,000
in 1979
in 1979(same(samepopulation
population
as Caoas CaoLanhLanhcity nowadays)
city nowadays)
to approximately
to approximately
1.2 million
1.2 million
in 2011.
in 2011.
By 2015,
By 2015,
it is forecasted
it is forecasted
to riseto to
rise
1.5tomillion
1.5 million
and 2.1
andmillion
2.1 million
in 2030
in 2030(Nedeco,(Nedeco,1993).
1993).

Flood adaptive
citiestowards
climatechangeadaption
andadaption
urban
in Mekongadaptivetowards
climatechangeand urban
development
FloodFloodadaptive
citiescities
towards
climatechangeadaptionand development
urban
development. . . . Delta......

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October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamAs the result, Can Tho had to transform to support the increasing population andeconomic development. City is becoming larger and denser. During 20 years, theurban areas have expanded double in size. The population growth led to thedevelopment of unplanned areas in the inner cities. This population movement
promoted an increasing of risky settlements located on lands sensitive to flooding.
Historically, the system of canals inside the city worked as a sewage system thathelps to drain off floodwater quickly to the rivers and store rainwater to other uses.
This system, however, did not work anymore in the dense urban areas. Many of
the waterways were polluted and cause health’s problems. They were filled andreplaced by underground drainage system that is not sufficient for the high rainfall
in Mekong delta. As the consequence, in 2006 rainy season, more than 80 percentof the city was flooded, water level reached to 0.5 meters. The historic flood of
2000, in particular, destroyed many rice crops, aquaculture farms, housing andother infrastructure in the flooded areas. The local government’s response to thisdisaster was to build a dyke system which should prevent such negative impacts
and after 2004, dykes were constructed throughout the province. Although the
new dyke system helped to reduce flood damages in whole of Can Tho city andthe lower flooding areas such as Kien Giang, Hau Giang, Soc Trang, Tra Vinhprovinces and secure agriculture in the flood protected areas, it also has
disadvantages to other areas in various ways. It is one of the main causes leading
to erosion, plant diseases, soil fertility decline and natural degradation in theprotected flooding areas of the Mekong Delta (Tran Nhu Hoi 2005; Duong Van
Nha 2006; Sarkkula et al 2008). Other negative impacts are changes in flow
velocity and annual flooding levels with negative effects in both protected andnon-protected flooding areas. Especially the high dyke system obstructs the finesediment flow into agricultural lands that causes a big conflict between Can Tho
City with the whole region.
These consequences are not only coming from unstable urban development
strategy or insufficient water management, but also from the lack of theintegration between these two disciplines. Without interventions, other delta cities
in Mekong Delta are predicted to develop in the same way and experience thesame problems as Can Tho City does in recent years. Despite new techniques,
however, the question then remains: How to integrate urban planning and water
management in the Mekong Delta?
4. LESSONS LEARNT FROM THE NETHERLANDS
Today, most delta areas in the world are dealing with the increasing complexity
and changing dynamics, because of two reasons: first, the changes in the naturaldynamics of the delta due to climate change and human interventions, and second,the changes in the dynamics of land-use, dominated by urbanization,industrialization, port-development, agriculture and leisure/tourism (Meyer, H.
and Nijhuis, S., 2011). Traditional approaches “protecting against flooding” or“building in nature” have not only separated nature from human and their urban

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development, but also damaged damaging to the nature system and humancivilization. Therefore, these damage forces people to take a step back rethink
about the problem, about their relationship with nature and understand intensely
the natural landscape before impacting nature. ‘Man and nature are indivisible,
and our survival and health are contingent upon an understanding of nature andprocesses’ (McHarg, 1969, p.27).
In the Netherlands, numerous long term planning studies and policies have been
implemented. The new approach is no longer about “protecting against flooding”
but instead respecting it and giving space for water and its natural landscape.
Based on a clear understanding of the delta system, the Dutch attempt to plan their
future with natural landscape, creating both healthy ecosystems and a safe country.
4.1 Room for the river
The process of urbanization in the Netherlands started from the 11th century thatwas based on agricultural exploitation of fertile soils. The Dutch landscape wassoon transformed from a natural swamp of peat and clay into a number of“polders” surrounded by dikes and drained by a system of ditches, canals andlocks (Meyer, H. and Nijhuis, S., 2011). Cities in these polders grew from theagricultural markets to the centres of regulation for the polder’s water system(Burke, 1960).
After disaster in 1953, the Delta committee was recognized to explore the cause offloods and asked to formulate an alternative approach on flood management in the
Netherlands. A new flood control approach was constructed to design the flood
defense system including: dams, sluices, locks, dikes, levees and storm surge
barriers. Nowadays, the flood prone parts of the country are protected by morethan 50 dike rings.
However, throughout a thousand years of protecting against flood, space for therivers has become only more limited. Drivers of change put greater threats on thedevelopment of the country. So to make the Netherlands a safe, comfortable andpleasant place to live, trend has to be reversed. The answer lies in the plan tomake more room for the river. As the Spatial Planning Key Decision, “Rooms for
the River” (Ruimte voor de Rivier 2007) policy was proved by Dutch government
in 2007. The policy outlines numerous designs to provide more space for the riverand lower high water levels (Figure 4). These designs present an integrated spatialplanning with the main objectives of flood protection, master landscaping and theimprovement of overall environmental conditions.

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October
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4.2. Multi-layer safety
Recent floods in Europe and hurricane Katrina have made the Dutch government
realize that flood protection policy should be wider in scope than just preventionof floods. Therefore, in 2008, the Dutch Government developed a sustainableapproach, multi-layer safety, that consists of three different layers. The first layer
is about flood prevention with strong dikes, dunes and storm flood barriers. The
second layer is sustainable, water proof and spatial planning. This layer aims at
reducing victims and limiting the damage from possible flooding. The third layer
is crisis management in case of flooding (Figure 5).
While old policy was just based on prevention, theconcept of multi-layer safety creates a more
complex environment for flood protection. It
requires the balance of roles and responsibilities ofpublic authorities, private institutions and citizens.
Thus, the effectiveness of appling this concept andthe roles of different actors in this, have to bediscovered in order to decide whether and how
muliti-layer safety can be organized, coordinatedand institutionalized (van den Heuvel, J. , Roovers,
G.J. , Eijer,M.M).
Figure 5. Model of multilayer safety
5. CONCLUSION AND RECOMMENDATIONSThe Mekong Delta today is a product of different engineering decisions
throughout three hundred year history. On one hand, agricultural production has
developed successfully, and economic growth and urbanization has been very
rapid. On the other hand, intensifying agriculture and large scale water control
structures have challenged the natural landscape and social equity (Käkönen,2008). The proposed strategy needs to create a new balance between safety,

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spatial quality, natural preservation and economic values that will benefit in all
local, regional and international scales.
Achievements from “Room for the river” and “Multi-layer safety” in the
Netherlands have marked a dramatic change in policy and thinking about water
management. It showed that the protection paradigm has changed from“protecting against flooding” to “living with flooding” and towards a tendency ofintegrating water management and spatial planning. It can be seen as a suitablestrategy to apply in the case of the Mekong Delta because:- Indeed, water as the basic element in nature landscape of the delta, have become
an indispensable element in the development of urban delta. The new strategy for
the Mekong Delta requires a sustainable water management that can provide asustainable use of floodwater, groundwater, surface water, waste water anddrinking water. This water management combining with the green spaces, such as:parks and pedestrian paths functions as an attractive place for social interaction.
- Infrastructure layer as the middle layer connecting nature and urban landscape
has achieved a lot of successes in creating safe conditions for human activities andurban development. Innovative infrastructure can design with more than just one
purpose, that is aligned with natural process rather than traditionally working
against them and that is adaptive to cope with changing conditions, such as:climate change and sea level rise (De Vriend, H.J. and Van Koningsveld, M.,2012). Especially when used in combination with the traditional approach, the
new infrastructure system can lead to cheaper, more economic potential and moreaesthetically appealing solutions.
- As a developing country, Vietnamese economy cannot support for large scale
infrastructure and high cost flood control project. Using natural processes of thedelta can help to make flood risk management more sustainable and cost-effective
than hard, engineered defenses. As Ian Mcharg argued each of the naturallandscapes is best suited for different land uses, spatial planning can work in a
way that flood resistance zone, buffer zones and flood hazards zones are identified.
For example, flood resistance zones are suitable for urban development, while inthe buffer zones, space for future defense measures is reserved, other economic
and recreation activities such as: ports, beaches and national park might bepossible.
- In recent years, Vietnamese government has built many residential clusters andencouraged people to migrate to safer locations in order to avoid flood damages.
However, this strategy received little attentions of the farmers who do not want toleave their farms. Therefore, the new strategy has to take into account providing
inhabitants a safe and attractive living and working environment. It is targeted at
different actors: government, developers, business owners, inhabitants…etc.

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REFERENCES
Bucx, T., Marchand, M., Makaske, A., Van de Guchte, C. (2009). Comparative
assessment of the vulnerability and resilience of 10 deltas– synthesis report.
Aquaterra 2009. Amsterdam: Delta Alliance.
Campanella, R. (2010). Delta Urbanism: Lessons from New Orleans. In New
Orleans: New Orleans (pp. 181-186). New Orleans: Amer Planning Assn.
De Vriend, H.J. and Van Koningsveld, M. (2012). Building with nature: Thinking,acting and interacting differently. Dordrecht, the Netherlands: EcoShape,
Building with nature.
Gupta, A. (2008). The Mekong River: Morphology, Evolution, Management. In A.
Gupta, Large Rivers: Geomorphology and Management. John Wiley & Sons Ltd.
Hans Dieter, E. and Simom, B. (2009). Strategic group formation in the Mekong
delta: the development of modern hydraulic society. WISDOM, Department of
Political and Cultural Change. Bonn: WISDOM.
McHarg. (1969). Design with Nature. New York: The Natural History Press .
Meyer, H. and Nijhuis, S. (2011). Towards a typology of urbanizing deltas.
Department of Urbanism, Faculty of Architecture Delft University of Technology.
Meyer, H., Nijhuis, S., Pouderoijen, MT. (2009). A Tale of Two Urbanized Areas.
In V. M. Meyer, Dutch Dialogues: New Orleans-Netherlands. Common
Challenges in Urbanized Deltas. Amsterdam: SUN Publishers.
Miller, F. (2006). Environmental risk in water resource management in the
Mekong Delta: a multiscale analysis. In T. a. Tvedt, A history of water. New
York: I.B.Tauris.
MRC. (2010). State of the Basin report. Mekong River Commission. Vientiane,
Laos: MRC.
Nedeco. (1993). Master plan for the mekong delta in Vietnam: A perspective
development of land and water resources. Ho CHi Minh City, Vietnam: GOV.
Nienhuis, P. (2008). An ecological story on evolving human environmental
relations coping with climate change and sea-level rise. In Environmental historyof the Rhine-Meuse Delta (p. 550). Springer Verlag.
Pham, D. (2011). Urbanized Mekong delta: A dialogue between water and land.
Shannon, K. (2009). Landscape as Urban Structure: the Case of Cantho, Vietnam.
In L. L. SCHWAB, Landscape-Great Idea. Vienna: ILA - Institute of LandscapeArchitecture.
Tayler, P. (2006). River into Roads: the terrestrialisation of a South - east AsianRiver Delta. In M. &. LEYBOURNE, Water: histories, cultures, ecologies.
Melbourne: University of Western Australia Press.
UN-Habitat. (2006). State of the Worlds Cities 2006/7:The Millennium
Development Goals and Urban Sustainability: 30 Years of Shaping the HabitatAgenda. Nairobi.
USDA. (2011). United States Department of Agriculture. Retrieved 2012, fromhttp://www.usda.gov: http://www.usda.gov/wps/portal/usda/usdahome

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van den Heuvel, J. , Roovers, G.J. , Eijer,M.M. (n.d.). Multi-layer cooperation inflood management: How to cooperate within flood management in public area's.

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Analysis on influencing factors ofcommunity participation in disastercountermeasures regarding land subsidence
and climate changecase study: North Jakarta (Indonesia) and
Shinkoiwa Community, Katsushika City,
Tokyo (Japan)
Maria Bernadet Karina Dewi 1, Takaaki KATO 2
Graduate student, ICUS, IIS, The University of Tokyo, Japandewi@iis.u-tokyo.ac.jp
2
Associate Professor, ICUS, IIS, The University of Tokyo, Japankato-t@iis.u-tokyo.ac.jp
1

ABSTRACT
Both Shinkoiwa in Katsushika City and North of Jakarta have been facing land
subsidence. Year by year the subsidence rate is increasing. Moreover, by the sea
level projection as an impact of climate change, flood risk will be higher. Floodcountermeasures should be approached not only by structural mitigation, but alsosocial adaptation which involves community. Those can be implemented throughpreparedness and response activities. This paper aimed to analyze the requiredcondition for successful process, and to find additional required condition forcommunity based activity in disaster countermeasures. With case study of
Shinkoiwa community in emerging community participation by experts and NPO,and community disaster risk reduction in Jakarta supported by NGO andprofessional urban planners group.
This paper analyzed the
Keywords: climate change, land subsidence, community participation, support
system1. INTRODUCTION
Land subsidence and climate risk are the background of this study. One impact ofclimate change is the rising sea level, which means increasing the inundation areaof flood. Land subsidence will make the climate risk higher. Therefore, we needto adapt to climate change, including various layer and approach, from the policy
making to the community based. Focus of this study is in adaptation measures incommunity based. As climate change continue gradually, adaptation measuresneeds continuity or sustainability.

491

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamThis research aimed to understand the hazard and risk and its community
participation for countermeasures, to clarify the required condition for successfulprocess, and to find additional required condition.

2. BACKGROUND OF SHINKOIWA AND NORTH JAKARTA
The land subsidence rate in Jakarta is -0.5 to -17 cm/year, and in Shinkoiwa is -4
m in total. Climate projection for sea level rise is 0.35 m or 0.23 to 0.47 m per 100
years. (IPCC, 2007). It will increase the inundation level of flood. The 5 researchareas have emerging community-based activity for flood countermeasures. Thereare 3 areas in North Jakarta supported by Indonesia Red Cross from 2007 to 2010,
which are Muara Angke, Muara Baru, and Marunda; 1 area has been supported byIndonesia Association of Planners from 2012 to present named Kamal Muara(Refer to Figure 3). And the area in Shinkoiwa has been supported by experts and
NPO A! Safety and Amenity Machidzukuri from 2006 to present.
2.1 Background of Shinkoiwa situation

Figure 1: Below sea-level area inTokyo(Kato, 2011)

Figure 2: Ground subsidence due toindustrialization(Kato, 2011)

Katsushika city is located on the eastern part of Tokyo. With its below sea level
geographic location, it has 31.5 km2 area under low tide sea level, 124.3 km2 area
under high tide sea level (Kato, 2010). To control the tidal flood, several
mitigation efforts have been done, such as super-high embankment constructedalong urban river (MLIT, 2006). Local government has also established flood
hazard map on the Arakawa River in 2007 (Katsushika City, 2007 in Kato, 2011).
However, many countermeasures need to be taken into account, such as moreevacuation space, and the mitigation during flood occurrence. Land subsidence
has started since 1909, and became apparent from 1945 to 1958. It was caused byindustrialization. The total subsidence is 4 meter.

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Figure 3: The water level in Shinkoiwa, Katsushika City in caseof flood (Kato, 2011)

2.2 Background of North Jakarta situation
The current situation of land subsidence in Jakarta has been increasing. As a
metropolitan city located in the urban area, its urbanization contributes into
ground water extraction. The groundwater extraction leads into increasing floodcatchment area. The mitigation and preparedness activity itself is not enough.
Utilizing community activity will give significant contribution towards disaster
preparedness countermeasures. During 1982-1987, the subsidence was from 20 to
200 cm in several points in Jakarta (Abidin, et.al, 2009). And though GPS
observation, in June 1997, there has been 7.5 cm to 32.8 cm subsidence within 4
years, depends on the local area where the points of measurement were located(Djaja, et.al, 2004). Generally, there has been approximate subsidence level of 1
to 15 cm per year, whereas in several locations reached 20-25 cm per year (Abidin,
et.al, 2009).

Figure 4: Subsidence map of Jakarta 19742010 by GPS:
Total subsidence -25 up to -400 cm ; rate 0.5 up to -17 cm/year (Andreas, et al, 2011)

Figure 5: Simulation of flood
considering the factors of tides, sealevel rise, land subsidence, ENSO,
and storm surge/tidal flood &exposure (Hadi, 2012)

Analysis on influencing factors of community participation in disaster countermeasures
Analysison influencing
factorsof communityin (Indonesia)
disaster . . . . . . . . . . .
regarding land
subsidence
and climatechangecase study:participation
North Jakarta
and Shinkoiwa Community, Katsushika City, Tokyo (Japan)493

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamBased on Andreas, et al (2011), due to land subsidence in the year 2010, there was
10.26% (66.355 x 106 m2) of Jakarta area below the sea level. This was following
as before 1990, there was none of the area below sea level. And based on his
prediction, in the year 2030, there will be 131.914 x 106 m2 or 20.41% of area
will be located below sea level. A simulation consists of hazard elements such astides (0.62), sea level rise (0.0057), land subsidence (0.001-0.035), ENSO (0.15),
and storm surge (2.5) (Hadi, 2012). The worst case is predicted to occur on thenorthern part too, indicated by red and orange colour in figure 5.

3. FIELD INVESTIGATION
Field investigation in Shinkoiwa, Katsushika City was done through interview tothe urban planning experts and participation in community activities towards
disaster preparedness from November 2011 until April 2013. Field survey inNorth Jakarta was done in January and March 2013, covering the 4 area. It wasdone by interview to the support groups, community leaders, community members,
and volunteers; also by participation in field investigation and survey by support
group members in order to find flood evidence and infrastructure survey.

Figure 6: Field survey in Shinkoiwa (2011-2013)

Figure 7: Field visit in North Jakarta (Muara Angke and Muara Baru), 2013

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Field investigation was aimed to get the risk-hazard by community, and thecountermeasures done by community, and the scheme and process of community
based activity towards disaster countermeasures. The current hazard in North
Jakarta is flood, caused by tide and rainfall, and in Shinkoiwa is flood andearthquake.
Support system by Red Cross to Muara Angke, Muara Baru, and Marunda wasdone in 2007 to 2010, with the activity as workshop, survey, disaster response andadaptation, and information dissemination. The objective of the support system isto achieve disaster preparedness and mitigation skills for community, and to have
network amongst them for disaster response. Support system by Association ofplanners to Kamal Muara has been done in 2012 until present, within the activities
of workshop, meetings survey, and technical support. The objective is to findcurrent problem of hazard, propose guideline for better and safer neighbourhood,and empower community for disaster preparedness and response. Support byexperts and NPO A! Safety and Amenity Machidzukuri has been done in 2006
until present, through workshops, stakeholders meeting, and disaster mitigation
simulation. The objective is to understand the risk of natural hazard, get important
key persons, and enabling sustainability of the activity.

4. ANALYSIS
The required condition for successful process has 3 findings:
First, focusing on definition of success by stakeholders (community leaders andsupport group) and the program achievement, all cases are successful. But
considering the aspect of sustainability, 3 cases are successful: Muara Baru,
Shinkoiwa, and Kamal Muara; and 2 unsuccessful cases: Muara Angke andMarunda. For the unsuccessful case, eventhough community has alreadyunderstand the risk, but they feel that they have no risk at all, they began to thinktheir ideal situation and do not have attention on disaster preparedness activities.
In general for all case studies, the definition of successful is when community
understand the risk, able to do the countermeasures, able to continue their effort,
and able to make the effort sustainable for the future and attracts more participants.
Success is related with sustainability, because of the climate change and land
subsidence risk. Climate change will give the risk of sea level rise. For example,
as predicted by the IPCC, the prediction of sea level rate 2 mm/year in Jakarta(IPCC, 2007). With the continuing climate risk, the sea level rise will also higher.
It is also influenced by the land subsidence level which is higher from time totime. While in period of 2010-2030 Heri predicted that with assumption of linear
trend, no act on stopping ground water extraction, another addition maximum is 2.6 meter subsidence might happened in north of Jakarta (Heri, 2012). By
increasing land subsidence and climate risk, the continuity of community
participation is needed to tackle with the future disaster.

Analysis on influencing factors of community participation in disaster countermeasures
Analysison influencing
factorsof communityin (Indonesia)
disaster . . . . . . . . . . .
regarding land
subsidence
and climatechangecase study:participation
North Jakarta
and Shinkoiwa Community, Katsushika City, Tokyo (Japan)495

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Table 1: Success definition and achieved goals
Support groups consists of several types, such as non-government organizations(NGOs), professional groups, and non-profit organizations (NPOs). They
approach the community, who already has their own characteristics, history, andlocal knowledge. Those communities has been facing the risk and hazard by time.
Thus the communities has its own countermeasures. The involvement of support
agency into this system creates a new support approach and process, and renewed
countermeasures.
Second, in order to be successful, this kind of process will be required: 1)
Someone from the outside must inspire the community, 2) After inspiration fromoutside, keypersons emerge from inside, 3) Community starts to understand thenatural hazard/risk precisely, 4) They need support system from outside, 5)Community starts to involve many people in the neighbourhood, and 6)
Community starts to make the activity sustainable. Those 6 factors was obtained
from the analysis in process of 4 cases.

Figure 8: The six steps of successful process of community
participation for disaster countermeasures

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Third, analysis on timeline of support group corresponding to the factors ofsuccessful process. All 5 case studies corresponds to the six factors of success asshown by the graph below.

Figure 9a: Support by Indonesia Red Cross to Muara Angke, Muara Baru, andMarunda corresponds to the 6 factors of successful process

Figure 9b: Support by Indonesia Association ofPlanners to Kamal Muara community corresponds to
the 6 factors of successful process

Analysis on influencing factors of community participation in disaster countermeasures
Analysison influencing
factorsof communityin (Indonesia)
disaster . . . . . . . . . . .
regarding land
subsidence
and climatechangecase study:participation
North Jakarta
and Shinkoiwa Community, Katsushika City, Tokyo (Japan)497

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 9c: Support by experts and NPO A! Safety and Machidzukuri to Shinkoiwa
Community corresponds to the 6 factors of successful process
The additional required condition for successful process has 2 findings:
First, both physical and social countermeasures are influencing each other. Strongsocial countermeasures tend to make the community have stronger physicalcountermeasures. Somehow, it will make people feel safe, thus they have lessactivity on social countermeasures. So it is the space where support group canhave role whether it will strengthen the social of physical countermeasures, bylooking at the community characteristics and risk-hazard.

Figure 10: Balance of physical and social countermeasures
There are two kinds of countermeasures, which are hazard control and awarenessto flood risk. Hazard control corresponds to physical facilities to control hazard,
such as dike and sewer facilities. This kind of physical countermeasures makes
the frequency of flood reduce, while at the same time it can make the awarenessof citizen to flood risk decrease. Countermeasures in community level have two
aspects, physical and social aspects. In social aspect it means that498

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countermeasures related to organizational or planning matters such as disaster
response plan and evacuation plan, and social system for confirmation of thesafety by community members. Physical factors is one to support social system in
a community such as construction of evacuation road and evacuation site. Thiskind of physical factors makes social system effective or should be combined withsocial system.
Balance between physical and social countermeasures is important to encourage
people preparedness towards hazard, and because both physical and social
countermeasures are influencing each other.
Second, the use of indigenous and local knowledge. As Shaw explained, due toexposure and proximity to hazardous conditions, a local population responds firsteven before assistance from aid-givers arrives at time of crisis (Shaw, 2012).
Based on his explanation, there are several terminologies of indigenous and local
knowledge, and the writer used in this is indigenous technical knowledge andcommunity-based knowledge. Shaw said that indigenous technical knowledge ismore framed on a technological perpective. It is related with traditional technicalculture. In the case study, the technical knowledge can be indicated by the twostorey houses of Bugis ethnic people who live in Kamal Muara, also mizuya houseand in Shinkoiwa case study.
In Kamal Muara, there are only 10% of total are the traditional two storey wooden
houses by newcomers from Bugis ethnic. This kind of house is adopted frompeople who are living in coastal area, thus it is responsive to flood. In Shinkoiwa
there are mizuya, which means traditional 2 storey annex to a house which islocated on elevated land. Basically people live on the first floor of main house. As
it is built on the elevated land, the first floor can be protected against small flood.
This type of houses only a few existing in Shinkoiwa. Because of modernization,
this housing type was demolished. Then they changed for wooden and concrete
houses.

Figure 11a: Traditional two storeys wooden
houses by Bugis ethnic people in Kamal Muara

Figure 11a: Mizuya in Shinkoiwa

The community-based knowledge is explained as the knowledge that community
Analysis on influencing factors of community participation in disaster countermeasures
Analysison influencing
factorsof communityin (Indonesia)
disaster . . . . . . . . . . .
regarding land
subsidence
and climatechangecase study:participation
North Jakarta
and Shinkoiwa Community, Katsushika City, Tokyo (Japan)499

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamget by interaction with other community members. This can be indicated by theheightening level of the house and the furniture for the community in North
Jakarta. Therefore, all stakeholders should consider the advantage of indigenous
and local knowledge in flood adaptation.
5. CONCLUSION
The required condition for successful process has 3 findings. First, focusing on
definition of success by stakeholders (community leaders and support group) andthe program achievement, all cases are successful. But considering the aspect ofsustainability, 3 cases are successful: Muara Baru, Shinkoiwa, and Kamal Muara;
and 2 unsuccessful cases: Muara Angke and Marunda. Second, in order to be
successful, this kind of process will be required: 1) Someone from outside must
inspire the community, 2) After inspiration from outside, keypersons emerge frominside, 3) Community starts to understand the natural hazard/risk precisely, 4)They need support system from outside, 5) Community starts to involve many
people in the neighbourhood, and 6) Community starts to make the activity
sustainable. Third, the timeline of support system corresponds to the 6 factors ofsuccessful community participation process, although all cases have different
activities and approach.
The additional required condition has 2 findings. First, social and physicalcountermeasures are influencing each other, and should be in balance. Second,Community use the indigenous and local knowledge such as traditional housing in
Kamal Muara and traditional structure called mizuya in Shinkoiwa. In
community-based activity, stakeholders have to consider the advantage ofindigenous and local knowledge.
REFERENCES
Abidin, et.al. (2009). Land Subsidence and Urban Development in Jakarta(Indonesia)
Andreas, et.al. (2011). Jakarta Subsidence: More Info. Jakarta Coastal Defense
Strategy (JDCS) Study Team. Institute of Technology Bandung and DeltaresDelft Hydraulic. Second Atlas Workshop JDCS June 28th 2011.
Djaja, et.al. (2004). Land Subsidence of Jakarta Metropolitan Area
Hadi, Safwan. (2012). Pemetaan Risiko sebagai Dasar Penanganan Dampak
Perubahan Iklim di Kawasan Pesisir. Studi Kasus DKI-Jakarta
Intergovernmental Panel on Climate Change (IPCC). (1997). IPCC Fourth
Assessment Report: Climate Change 2007. http://www.ipcc.ch
Kato, Takaaki. (2011). The Community-based Planning and Consideration ofCountermeasures through Workshop in “Below-sea-level city” against
Forthcoming Flood Disasters – Case in Katsushika City in Tokyo. ICUS.
Institute of Industrial Science, the University of Tokyo.
Ministry of Land , Infrastructure and Tranport (MLIT), Arakawa-Karyu River
Office. (2006). The Arakawa: River of the Metropolis – A comprehensive
guide to the lower Arakawa.
Shaw, Rajib. 2012. Community, Environment and Disaster Risk Management
Volume 10- Community-Based Disaster Risk Reduction. Bingley: Emerald
Group Publishing Limited.

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Assessment of multi-hazard risk
in mega cities in Japan
Tomofumi IKENAGA1, and Miho OHARA2
Undergraduate Student, Department of Civil Eng.,The University of Tokyo, Japanikenaga@iis.u-tokyo.ac.jp
2
Associate Professor International Center for Urban Safety Engineering (ICUS),
Institute of Industrial Science, The University of Tokyo, Japan
1

ABSTRACTThe 2011 Great East Japan Earthquake was historically huge disaster in Japan.
However, it should not be overlooked that the possibility of such a big disaster
was much lower than that of other disasters, which would cause less but still
serious effect. This earthquake also taught us the necessity of considering various
risk of natural hazards in addition to single hazard. It is necessary to identify
where safer lands are considering multi-hazard risk and to plan better use of
these safer lands.
This paper aims to integrate the risk of various disasters such as flood orlandslide, earthquake disasters, etc. and analyze regional multi-hazard risk inmega cities in Japan. Moreover, the number of people exposed to the multi-hazard
risk was analyzed. At first, existing hazard maps for various kinds of natural
hazards were collected and overlaid on GIS database. As a result, the areas withor without hazards were identified. The correlation among different types ofnatural hazard in mega city was also analyzed. Then, the population who exposed
to single or several hazards in mega city was assessed and regional vulnerability
was evaluated. The land with no disaster risk should be recommended to be
developed more in the future. On the other hand, in the area with high risk ofseveral disasters, countermeasures just considering single kind of disaster are notsufficient, but considering complex disasters are necessary.
Keywords: multi-hazard risk, population exposure, hazard map
1. INTRODUCTION
The 2011 Great East Japan Earthquake was historically huge disaster in Japan.
This earthquake taught us the importance of taking prepared measures for tsunami
such as regular evacuation drills. But this does not just mean that the measures fortsunami are the most important than others. In spite of the big economic loss inthe affected areas, some disasters have not got much attention specially if there
are few deaths. In 2013 Japan had much longer rainy season in early summer.
This abnormal weather caused unprecedented heavy rain bringing serious damage
in some region, especially in Shimane and Yamaguchi. Fortunately this series of501

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Vietnamcalamity did not kill many people, but it also shows the threat of strong rain inmega cities seems to be paid less attention than that of earthquake or tsunami.
There are various kinds of natural disasters, and what is the important thing is tomake fair comparison of these risks to formulate the best strategies for multihazard risk of disasters. Emotional anxiety about big disasters should not bringexcessive investments for a particular hazard and cause lack of measures foranother hazard, which does not attract much attention from society but probably
cause serious damage.
The 2011 Great East Japan Earthquake also taught us the necessity of consideringvarious risk of natural hazards in addition to single hazard. Many people living
near the sea were killed by the tsunami regardless of the eagerness to decrease therisk of earthquake. It is necessary to identify where safer lands are considering
multi-hazard risk and to plan better use of these safer lands.
This paper aims to integrate the risk of various disasters such as flood or landslide,earthquake disasters, and analyze regional multi-hazard risk of Japanese land. The
correlation among different types of natural hazard in mega city was also analyzed.
Then, the population who exposed to single or several hazards in mega city wasassessed and regional vulnerability was evaluated.
2. METHODOLOGY
2.1 The definition of the risk area
In this paper, the risk area of single hazard is defined as follows. If the J-SHIS(Japan Seismic Hazard Information Station) suggests that the big earthquake
which comes approximately once in one hundred years causes an earthquake witha seismic intensity of a lower 5 or greater on JMA scale, such area is regarded as
the risk area of earthquake. And the risk area of inundation by river water andlandslide is determined based on the hazard map published by prefectures or
MLIT (Ministry of Land, Infrastructure, Transport and Tourism). The multihazard area is the area that has overlap of two or three dangerous areas. The risks
of inundation inside a levee, high tides, tsunami, and volcanic eruption are notconsidered because of the difficulty on getting hazard maps in digital format.
2.2 Risk assessment
At first, existing hazard maps for various kinds of natural hazards were collected
and overlaid on GIS database. As a result, the areas with or without hazards wereidentified. Then the risk of single or several hazards was assessed by calculating
the size of risk area in each mega city and the population exposure, that is, thenumber of people living in there. The size was calculated by geometric operation,
one of the functions of Arc GIS. In the evaluation of the population exposure, 1
kilometer mesh data of population in 2005 was used. With regard to each mesh,
the size of the areas with hazards and the population exposure was assessed asfollows (equation 1). Population exposure to hazards is calculated based on theratio of risk area over total mesh area and the total population in the mesh.
Ph = P ×Sh / S(1)

Ph: Population exposure in the mesh

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P: All population in the mesh
Sh: Size of area with hazards in the mesh
S: Size of the mesh
After figuring out the size and population exposure of hazardous areas, mutual
correlation between these two factors was depicted with a graph. If many people
live densely in the area with several high risks, the area seems to have especiallyhigh vulnerability to natural disasters.
3. RESULTS
The risk was assessed in the three mega cities in Japan, Tokyo, Aichi, and Osaka.
These cities are located in eastern, middle, and western area of Japan, and they
have 13 million, 7.2 million, and 8.8 million people, respectively. There are 30
million people, a quarter of all population in Japan, in these three mega cities
although their size is just 3% of the country. The results of overlaying hazard
maps are shown in figures 1, 3 and 5. And figures 2, 4 and 6 show the rate of risk
area to the whole prefectural area in terms of size and population.

Figure 1: Hazard maps of Tokyo

Assessment ofAssessment
multi-hazard
risk in mega risk
citiesJapanof multi-hazard
in in
mega
cities in Japan503

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Figure 3: Hazard map of Aichi

Figure 4: The rate of risk area in Aichi

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Figure 5: Hazard maps of Osaka

Figure 6: The rate of risk area in Osaka
These maps show almost all the lands have the risk of earthquake. And many
people live densely with flood risk while few people live with the danger oflandslide.
The flood risk area is located in the vicinity of a river or sea while that oflandslide is near mountainous area, so these two areas has less overlap. But thelarge area with flood risk also has the high earthquake risk probably because of
the soft soil condition with fluvial sedimentation.
It can be found that the proportion of those who live with multi-hazard risk to thewhole population is roughly within a range from quarter to half.

Assessment ofAssessment
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citiesJapanof multi-hazard
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4. CONCLUSIONSIn this paper, existing hazard maps for various kinds of natural hazards werecollected and overlaid on GIS database. As a result, the areas with or withouthazards were identified. The correlation among different types of natural hazard
in mega city was also analyzed. Then, the population who exposed to single orseveral hazards in mega city was assessed and regional vulnerability wasevaluated.
It is necessary to assess multi-hazard risk in the whole area of Japan although theassessment is confined to three mega cities in this paper. Evaluating the risk of all
prefectures will make possible cluster analysis of them, which can be useful tounderstand the characteristics of disasters risk and formulate the best strategies for
totally mitigating the threat of disasters. The risk of each single hazard should beclassified according to the magnitude of disasters to analyze the risk in moredetail.
REFERENCES
Nojima, N. 2004. Macroscopic assessment of seismic risk in Gifu prefecture interms of population exposure to seismic intensity. Tono Research Institute ofEarthquake Science, Gifu, 37-53.
J-SHIS (Japan Seismic Hazard Information Station).
http://www.j-shis.bosai.go.jp/en/
National Land Numerical Information download service.
http://nlftp.mlit.go.jp/ksj-e/index.html

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Development of an innovative stormwater
management framework toward building
cities resilient to climate change in Vietnam
Duong Du BUI1,2,*, Kieu Duy TRAN1, Thanh Ngoc TONG3, Tung Son
NGUYEN1
1
Hanoi University of National Resources and Environment (HUNRE), Vietnam
2
NUSDeltares, National University of Singapore (NUS), Singapore
duongdubui@gmail.com; bui@hunre.edu.vn
3
National Center of Water Resources Planning and Investigation, Vietnam(NAWAPI)
ABSTRACT
Frequent urban floods have remained as key challenges to various socioeconomic activities and threaten sustainable development of many regions andcountries around the world. Growing evidences show that traditional approachesof urban stormwater management in Vietnam, which mainly depend on
engineering measures to immediately release stormwater to drainage system,
have failed to manage recent urban floods, especially extreme floods due toclimate change and rapid urbanization, and “wasted” rainwater resources. This
study thus proposed an innovative approach, which is based on concepts of a
traditional indigenous knowledge widely practiced in rural areas in Vietnam:
Vuon-Garden, Ao-Pond, Chuong-Livestock (VAC). The proposed approach,namely VAC Infrastructure (VACI), deals with urban stormwater at sources, on
pathways and at receptors with uses of various infrastructures related to concepts
of VAC agricultural system. VACI is preliminarily examined with case study ofHanoi city. The findings showed that the proposed framework provides promisingsolutions toward building a livable city resilient to climate change because it
helps to bring people closer to nature in cities where water, green, andbiodiversity are enhanced. Though the proposed approach was initially developed
at conceptual level, the findings provide useful foundation for developing aholistic framework which manages stormwater as “resource” rather than
“waste” or “problem”.
Keywords: urban flooding, stormwater management, VAC system, city resilience,climate change, Hanoi
1. INTRODUCTION
1.1 Current flood situation
In recent years, along with the erratic, extreme weather, sea level rise and changes
in surface conditions caused by urbanization process, the frequency and severity
level of floods have tended to increase (Tong, 2012, Bui, et al., 2010). According
to statistics in the number of global disasters from the World Health Organization(EM-DAT, WHO), in the last 30 years, floods accounted for 33% of all natural507

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disasters, and the number of people affected by flooding is about 52% of the total
number of people affected by natural disasters (Figure 1). It is noticed that Asian
regions most suffered from flooding in both aspects of the number of incidents
and the level of damage (number of people affected), with over 50% of the total
floods and 90% of the total number of people affected (Bui, et al., 2011).
Recently, the number offloods (Figure 2) andlosses of life due tofloods tend to rise andmay continue to increasein the future. The main
reasons are the highdensity of population incities due to process ofurbanization and theincreasing of extreme
weather
events.
Increasing trend in flood
events and damages areclearly
revealedin
Figure 1: Numbers of people affected by climatedeveloping
countries.
related natural disasters (1979-2008) (Bui, 2011)
Accordingtotheprojection, the number of people affected by flooding will increase toapproximately 2 billion by 2050 and the consequences are unpredictable in the
future due to effects of climate change, sea level rise, global warming,
urbanization, among others. [1].

Figure 2: Global trends in numbers of natural disasters during the period of 19792008. (Source: ICHARM, 2008 (Bui, 2011)).
1.2 Impacts of urbanization on rainfall-runoff process
Among different types of floods, urban flooding likely occurs most frequently andcan cause the most property damages and death toll. To be able to propose
effective solutions for urban flooding, we should first understand the causes ofurban flooding and the impacts of urbanization on floods. Typically, floods are theresults of a synthesis process of three main driving factors: meteorological (rain,

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storm, snow ...), hydrological (humidity and soil permeability, rivermorphology...) and anthropogenic factors (land-use pattern, urbanization,
deforestation ...). Depending on the dominance of each factor, flooding can havedifferent characteristics. Generally, floods can be grouped into the several
categories: local flooding, riverine flooding, flash flood…

Figure 3: Conceptual diagram presenting effects of urbanization on rainfall-runoff
process Source: FISRWG, 1998

Flood peak (Natural)

Runoff (Natural)
Runoff (Urban)

Figure 4: Effects of urbanization on flood hydrograph and lag time (time fromrainfall peak to flood peak)
Development of an innovative stormwater management framework toward building
Development of an innovative stormwater management framework toward building cities
cities resilient
to climatechangechange
in Vietnam
resilientto climate
in Vietnam509

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October 2013, Hanoi, Vietnam

In urban areas, the decline of natural infiltration due to built-up areas has resulted
in the generation of higher surface runoff flow in comparison to the natural
watershed (Figure 3). Moreover, urbanization led to the reduction of lag time- thetime from rainfall peak to flood peak (Figure 4) thus made the flooding faster andmore difficult to cope with. In other words, urbanization would increase flood
risks in both terms of occurrence and level of severity.
2. THE CONCEPT OF FLOOD RISK MANAGEMENT
Traditional approaches in flood management are primarily using structural
solutions to achieve the goals of flood control. Practices and studies [3],[4],[6]showed that this method is difficult to implement and ineffective in cases ofabnormal complex weather events, as well as to assess the damage caused by thefloods in areas with different infrastructures and socio-economies conditions.
Therefore, in recent years, new approach of “flood risk management”, rather thana traditional approach of “flood crisis management” has been implemented, inwhich, we can take into account three factors: Hazard, Vulnerability and Exposure.
This method has proven to be more flexible and more holistic than the old ones,
especially in developing countries.
What is Flood Risk
Management?
As defined by the United
Nations
International
StrategyforDisaster
Reduction (UN/ISDR) andthe
UnitedNations
University
InstituteforSustainability and Peace(UNU-ISP),
flood
risk
management concerns aboutfour main factors:
Hazards:
The
possibility, severity level andFigure 5: Proposed Urban Flood Risk
duration of floods;
Management based on the concept of Natural
Exposure: Elements
Disaster Risk Management by UNU (Bui, et
at risk when floods happen;
al, 2010) &UN/ISDR)
Vulnerability:The
population, social, economicand environmental factors;
Capacity: Awareness, preparedness and ability to cope with floods.
As given by the above definition: Flood risk is proportional to three factors:
hazards, exposure, vulnerability and inversely proportional to the ability to adapt(capacity). In context of urban flooding assessment and management, enhancing
our "adaptive ability" also means that we reduce the "vulnerability" thus thedefinition of UNISDR can be shortened as described in the formula (1) andillustrated by Figure (5).
Flood Risk = F (Flood hazard, Vulnerability, Exposure)

510

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3. GROUPS OF KEY MEASURES
3.1 Measures for flood hazard reduction
3.1.1 The proposed conceptual framework
As discussed previously, the main difference between the an urban catchment anda natural one is the increasing of built-up areas resulting in the higher surface
runoff and flood peaks in urban area. Therefore, promising solutions to reduce
urban flood risks are to enhance more “natural” built elements while constructing
infrastructure in urban areas in order to restore the natural rainfall-runoff process.
This approach will increase the use of "natural" structures with characteristic ofhigh permeability and ability of storing water such as water infiltration trench,
ponds, artificial wetlands, artificial vegetation cover, environmental buffers, etc.,.
to slow down the rainfall-runoff process and reduce the flood peaks thereby
reduce flood risks. At the same time, proposed infrastructure also helps improving
water quality, beatifying the landscape and the environment of urban area,
increasing biodiversity in urban areas as well as the ability to adapt to climatechange, with abnormal weather events and phenomenon of "heat islands" inurbanized areas.
In Vietnam, many cities have been struggled to solve the problems of urban
flooding by using traditional approaches which focus more on improving thedrainage system to drain stormwater as quickly as possible. Most of the rain water
is not adequately treated before flowing into the flood conveyance systems (i.e.
river, channel...), resulting in many environmental adverse consequences that
affect people's health during the flood season. The practical evidences have shownthat traditional approaches have many drawbacks, such as: the ineffectiveness offlood drainage, avoiding floods in certain areas but increasing floods in others,
wasting valued rainwater, causing environmental pollutions, depletion of riverflows in the dry season, etc.,.
Therefore, the key idea is to reduce urban flood risks by integratedly managing
the entire rainfall-runoff process: at the Sources, on the Pathway, to the
Receptors (Figure 6) with various environmental-friendly structural measures,such as: green roof, green wall, underground storages and infiltration systems,
bio-treatments, bio-detentions, bio-swales, etc.,. Using this approach, we not only
reduce flood risks (i.e. deduction of flood peak and volumes), but also retain andtreat stormwater which would later be used to relief water supply stresses,
increase groundwater recharges, maintain base flow in the rivers, improve habitat,
increase biodiversity and create beautiful city landscape.
In that sense, a Vietnamese traditional knowledge, namely VAC that is widelypracticed for poor families to be self-sustainable in rural regions, is highly
appropriate and adoptable. Originally, VAC means "Vuon-Garden, Ao-Pond,
Chuong-Livestock" which provides vital foods and water for family's daily needs(Figure 6). In the context of cities, VAC has its new meanings: Green-WaterBiodiversity, which are essential components shaping Livable and Sustainable
Cities. With these VAC Infrastructures, so called “VACI”, urban area will begreener, cleaner, more beautiful, sustainable and harmonious with nature, where
flowers and green (Vuon-Garden), water (Ao-Pond) and Biodiversity (ChuongLivestock) will be will be the core components of a sustainable cities.

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cities resilient
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October 2013, Hanoi, Vietnam

Figure 6: Simplified sketch of Vietnamese VAC Integrated farming system@SDWA
Figure 7: Proposed VACI framework for urban stormwater management

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Figure 8: VACI framework in reducing urban flood risks: case study of Hanoi city.
Illustrative figure adapted from urban flood risk management measures by A. K
Jha, R. Bloch and J. Lamond, 2011.

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October 2013, Hanoi, Vietnam

3.1.2 Application of VACI framework to reduce flood risks in Hanoi city
Applying VACI stormwater management framework (Fig. 7) to given urban areas
requires different specific measures to suit the local conditions of the areas. In thisstudy, VACI framework is initially examined to Hanoi, the capital of Vietnam asa case study. As Hanoi located in the lowland of the Red River Delta, the risks ofboth internal flooding and external flooding caused by the Red River during flood
season are very high. Flood risk management strategies for Hanoi thus must be
developed from integrated and holistic perspectives which cover different scales:
catchment, city, community and household scales as shown in Figure 8.
At each scale, specific solutions need flexible combinations between structuraland non- structural measures and a right balance between short term and longterm strategies to minimize the cost and maximize the effectiveness. For example,
flood risk management strategies at catchment scale need a right mix between
structural measures such as forest plantation, flood storages, dams and reservoirs,
barrier and barrages systems, etc., and non- structural measures such as flood
insurance, compensation, emergency planning, etc.,.
3.2 Solutions for increasing resilience/reducing vulnerability
Although the application of VACI strategies is promising and potential to reduce
the flood risk in cities; it cannot guarantee the absolute avoidance from the flood
risks, particularly in the context of erratic weather caused by climate change.
Therefore, it is necessary to combine between risk management measures and thesolutions that increase resilience/reduce vulnerability in order to minimize flood
risks effectively. These types of solutions also need a flexible combination andright mix between structural measures (such as flood shelter, emergency
assistance systems and evacuation routes) and non-structural measures (softsolutions). Non-structural measures can be divided into four main categories asfollowings:

Figure 9: Proposed integrated communication system to respond to floods in
Hanoi

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Figure 10: Spatial distribution of temporary wooden houses and homeless people
in Tokyo(Source: Takahashi, 1998)- (1) Raising public awareness and improving preparedness before flood events:
We need to implement educational programs, promote media to raise publicawareness about the possibility of flood risks in their living areas and the extent ofpossible damage might occur, as well as the preparatory work to minimize
damages caused by floods. Raising public awareness can be done in a number ofways, such as: using bulletin board in highly populated areas, posters, newspapers,
meetings, presentations, TV/Radio, photo exhibitions, training courses, or
integrating useful information related to floods into local social activities.
- (2) Planning for emergency assistance during flood events: implementation of
rescue and evacuation plans, providing food, water and other basic needs(medicines, shelters...) play important roles in reducing flood damages when thefloods is occurring. In addition, early warning systems and communication
systems that help convey flooding information to people quickly and accurately isalso very necessary. Figure 9 illustrates the proposed integrated communication
system to respond effectively to the floods in Hanoi.
- (3) Improving damage recovery after flood events: During and after the flood
events, the rapid deployment of remedial solutions, security, food, energy,
sanitation, health care, financial assistance is necessary to help people quickly
recover to daily life.
- (4) Assessing vulnerability: The comprehensive assessment of vulnerability,
including economic, infrastructural, social and cultural aspects is necessary. Whenflooding occurs, vulnerable groups of people such as poor families, the elders,single people, homeless people, foreigners, etc.,. will bear higher risks to floods.
Currently, the vulnerability in terms of culture, society, traditions is often
improperly cared and not incorporated into practical flood risk management
planning, though various researches have been highlighted the importance of
these factors in reducing flood damages. For example, in Tokyo (Takahashi,1998), in the 1970s, up to 70% of the elders (> 65 years old) lived with theirchildren, but currently, this dropped to only about 32%. With people living inTokyo, radio and TV are the only sources of information when disasters happen
and most families are of only 1 or 2 people (higher risk than families of more
people). Despite of the increasing in the number of foreigners in recent decades,
all the forecasts, warning, guiding to shelters, evacuation… related to natural
disasters remain entirely in the local language- Japanese. Takahashi (1998)
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October 2013, Hanoi, Vietnam

studied the relationship between disaster risk capabilities with social factors suchas the distribution of temporary wooden houses and homeless people in Tokyo(Figure 10).
4. CONCLUSION
Annual flooding has caused serious damage to the economic and social activities,
threatening the sustainable development of countries and territories around theworld. The planning for strategic direction and implementation of the appropriate
measures to prevent flooding damages in urban areas is the urgent but challenging
tasks to many countries. Under the impacts of climate change and urbanization,
the traditional methods to cope with flooding revealed many shortcomings
especially with the recent floods. Therefore, a new approach based on theprinciples of risk management methods is proposed. This approach is primarily
composed of two main groups of measures: measures of reducing the flooding
hazards (i.e. reduction of flood occurrences and severity), and measures toincrease resilience or reduce vulnerability. In this approach, we need to implement
flexible combination between short-term and long-term solutions as well as
between structural and non-structural measures. Solutions of reducing flood risk
were studied within conditions of Hanoi, while the solutions of increasing
resilience / reducing vulnerability are analyzed with illustrations from the actual
data from the recent study conducted in the city of Tokyo. The results showed thatin Hanoi, the solutions should be implemented comprehensively in different
scales from river basins to residential households in order to reduce the risk offlooding effectively. Research in Tokyo has shown that comprehensive
assessment of vulnerability, including culture, society, traditions ... also plays avery important role. The methodology developed in this research has opened apromising approach for a more holistic and flexible management of urban
flooding.
ACKNOWLEDGEMENTS
This study was carried out as a part of the project “Improvement of Groundwater
Protection in Vietnam-IPGVN” supported by Germany Government and the
project “Hanoi inundation mapping in context of climate change”, financed by the
Hanoi Metropolitan Government.
REFERENCES
Tong, N. T., et al., 2012. Technical Report of the Hanoi’s Government-funded
project “Hanoi inundation mapping”, National Centre for Water Recourses
Planning and Investigation (NAWAPI), 297 pages.
Tran, D. K., 2012. Managing Extreme Floods in the Lam river basin, Vietnam.
PhD thesis, Water Resources University, 165 pages.
Bui, D. D., et al., 2010. Understanding Flood Hazard, Vulnerability and Coping
capacity in mega cities: Reflections from Tokyo. The United Nations University
Institute for Sustainability and Peace (UNU-ISP), 93 pages.
Bui, D. D., et al., 2011. Technical guideline on water-related disastermanagement for drought (part IV). World Federation of Engineering
Organizations - WFEO, 135 pages.

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Federal Interagency Stream Restoration Working Group (FISRWG), 1998. Stream
Corridor Restoration: Principles, Processes, and Practices, 653 pages.
The United Nations International Strategy for Disaster Reduction (UN-ISDR),
2009. Terminology on Disaster Reduction, 35 pages.
Takahashi, S. 1998. Social Geography and Disaster Vulnerability in Tokyo.
Applied Geography 18 (1): 17-24.
Workshop to Produce an Information Kit on Farmer-proven. Integrated
Agriculture-aquaculture Technologies (IIRR; 1992; 119 pages)
A. K Jha, R. Bloch and J. Lamond, 2011, Cities and Flooding: A Guide toIntegrated Urban Flood Risk Management for the 21st Century, The World Bank,
637 pages.

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Assessment of potential greenhouse gas
emission of domestic solid waste treatment
in Hanoi, Vietnam
Minh Giang HOANG
Lecturer, Department of Environmental Technology and Management, IESE,
National University of Civil Engineering, Vietnam
hmgiang83@gmail.com
ABSTRACT
Domestic waste in most of developing world cities including Hanoi havediseperately collected and primarily landfilled. It caused a large amount ofgreenhouse gas (GHG) emissions. This study aim to estimate and compare theamount of GHG emission from operating domestic solid waste treatment facilities
in Hanoi city by using the IPCC 2006 method from various possible scenarios. Inoder to use Tier 2 model of IPCC 2006 for GHG estimation, an analysis on
current household solid waste management system of the city was obtained byusing MFA approach. There was a reduced of around 70% of the amount of CH4
emissions and up to 60% of total GHG saving (CO2-eq) from avoiding organic
waste to landfill as well as increasing material recovery through composting andrecycling of household waste.
Keywords: waste treatment alternatives, GHG emission, household solid waste
1. INTRODUCTION
Climate change is a major international concern for modern society. Since the preindustrial era, atmospheric concentrations of carbon dioxide (CO2) have increased
by 35% and methane (CH4) concentrations have more than doubled (ISWA, 2010).
Together with greenhouse gas mitigation strategies and technologies from main
emitters according to the Intergovernmental Panel on Climate Change (IPCC)
such as Energy sector; Industrial processes and product use sector (IPPU),
Agriculture, forestry, and other land use sector (AFOLU) etc… Scientists all over
the world has clearly taken on the commitment to make a contribution so that thewaste sector may change its status at the global level – from being a net
greenhouse gas emitter to becoming a net GHG saver (Savino, 2009).
Cities in developing countries, Hanoi included have unsorted solid waste
collection system and landfill is the primary disposal method, which is a major
source of GHG emissions from the waste sector (UNEP, 2010). Low efficiency ofwaste collection system leads to a great amount of household solid waste released
to the environment. Solid waste is not separated at source resulted in lost
opportunities for resource and energy recovery as well as treatment technology519

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Vietnamapplication. Moreover, contemporary practices of dealing with waste in Hanoi
gave way to less environmentally friendly alternatives, such as the disposal ofwaste in riverbanks, empty space or open burning within urban areas. The current
solid waste treatment facilities contributed a great amount of GHG emission,
especially methane from sanitary landfill and it plays an important role of impact
on global warming.
The 2006 IPPC (IPCC, 2006) provided a methodology for annual accounting of
GHG emissions for the waste sector, defined by the IPCC, is different from how
the waste management industry perceives itself (Gentil et al., 2009). Certainly, thereporting methodology of the IPCC waste sector identifies only the directemissions of post-consumer waste management and recycling, intermediate waste
facilities as well as waste transportation are excluded. The method is crucial inassessment of the potential of GHG emission/mitigation associated with allactivities or sectors within a reporting country.
This study aimed to assess the impact of solid waste treatment practices,
especially household waste towards GHG mitigation for the IPCC waste sector.
Thus, the study proposes to use the 2006 IPCC method to evaluate greenhouse gas
emission. A case study for Hanoi city in 2011 has been conducted under somepossible scenarios, which are suitable for the current situation of the city.
However, because of the complex waste management in the city, a material flow
analysis (MFA), therefore, have carried out on household solid waste management
system in order to obtain a database of waste stream for applying the Tier 2 modelof 2006 IPCC guidelines.
2. METHODOLOGY
2.1 Research target area
The purpose of this study assessed the amount of GHG emission from solid waste
treatment activities in Hanoi city, which had a great size of population of around
6,5 million in 2010. The number of urban residence accounted for 43%, while thenumber of peopel living in countryside is 3,8 million, 57,4% (HSO, 2011). The
concerning target of the research was systematical an analysis of the household
waste stream of the city in 2011 and calculation the directed greenhouse gases
according to the 2006 IPCC guidelines such as CH4 and N2O, emitted fromlandfill and composting plant activities. The 3 main landfills and 3 composting
facilities in Hanoi was taken into acount in this study including Nam Son, Xuan
Son, Kieu Ki as well as Cau Dien, Kieu Ki, Seraphin respectively.
2.2 Scenarios description
In order to assess the potential contribution of GHG mitigation of solid waste
management alternatives for Hanoi city. Some reasonable waste management
scenarios were assumed with the priority of keep using temporary solid waste
treatment technologies but improving collection efficiency and seperation atsource application. Scenarios description was illustrated in Table 1.

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Table 1. Scenarios description
Scenarios

S1

Collection
rate
Urban area
95%
Countryside
60%
100%.

S2

100%

HT
(business as
usual)

Separation at source
Not
separatesourceTechnologies descriptionatLandfilled without LFG recovery
CompostingYes
The percentage ofrecyclable
waste
recovered up to 80%.
Yes
The percentage ofrecyclable
waste
recovered up to 80%.

Use current technologies:
Landfilled without LFG recovery
Composting 100% organic waste
LFG recovery:
Landfill with LFG recovery with the rateof 20% of CH4 recovered
Composting 100% organic waste

2.3 Waste material flow analysis
2.3.1 Waste quantity and composition data
The data of household waste related to analysis in this study have been obtained
from published report in 2011 of Hanoi urban environment one member limited
company (URENCO, 2011) and National report on environment 2011: solid waste
by Ministry of Natural Resource and Environment (MONRE, 2011). In addition,
research data conducted by JICA was used in the study. The household waste
generation and collection rate of urban area and countryside area of Hanoi in 2011
have been introduced in those reports above and also calculated in Table 2.
Table 2. Household waste generation and collection of Hanoi in 2011
Area
Waste generation in the whole city
Waste generation in urban area
Waste generation in countryside area
Waste collected in urban area
Waste collected in countryside area
Total waste collected

Collection rate (%)
95%
60%

Amount (t/d)
6500
4100
2400
3895
1440
5335

The household solid waste information including waste quantity and compositionby physical categories of the city as well as landfills was provided by URENCO
and MONRE, also calculated and summarized in Table 3.
Table 3. The composition of waste of the city and landfills in 2011
Urban Area
Composition
Paper i
Plastic i

Countryside Area

Percent(%)*

Amount(t/d)

Percent(%)*

Amou
nt (t/d)

4,85
4,02

198,85
164,82

2
2,05

48
49,2

Percent ofwhole thecity (%)***
3,80
3,29

Percent of waste
composition in LF
Nam
Xuân Kiêu
Sơn
Sơn
Kị
**
**
****
6,53
5,38
5,47
13,57
8,35 11,89

Waste
moisture
(%)
***
57,63
53,91

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Vietnam0ctober
VietnamNylon i
Metal i
Organic waste
Rubber, leather
TextileWood
Glass
Ceramic
inert
Hazardous waste
Amount (t/d)**, ***

8,48
2,18
38,03
4,15
2,15
3,02
2,79
7,36
22,74
0,23

347,6889,38
1559,23
170,1588,15
123,82
114,39301,76932,34
9,43

5,35
0,4
56
1,8
1,86
2,24
1,3
0,7
12,2
14,1

4100

128,4
9,6
1344
43,2
44,64
53,76
31,2
16,8
292,8
338,4

7,32
1,52
44,67
3,28
2,04
2,73
2,24
4,90
18,85
5,35

0,87
53,81
0,15
5,82
2,51
1,87
0,39
14,31
0,17

0,25
60,79
0,22
1,76
6,63
5,08
1,26
9,46
0,82

0,46
56,84
0,83
4,32
4,44
2,5
0,84
12,14
0,27

2400

6500

3468

227

118

(*)

Source: Report on Solid waste in 2011 of Hanoi URENCO (URENCO, 2011)(**)

Source: National report of environment 2011 – Solid waste (MONRE, 2011)

53,91
70,00
0,72
9,9
30,9
-

(***)

Source: Report on solid waste management research in Vietnam 3/2011 (JICA, 2011)(****)

Calculated based on data of waste composition of some landfills in the northern Vietnam such as Nam
Son, Xuan Son, Trang Cat, Dinh vu (MONRE, 2011)i

Type of recycle waste in private business and recycling villages

According to URENCO, the amount of waste collected in 2011 was 5335 tons/day,
meanwhile that of waste treated was only 3972 tons per day according to JICA
(2011), accounted for 75%. It was possibly as a result of recycle activities throughwaste pickers and junk-man as well as low efficiency of waste collection activities.
The two official household waste treatment methods in Hanoi currently arelandfills and composting. In 2011, the total amount of organic waste treated incomposting plants was 159 tons per day while that of house hold waste landfilled
in Nam Son, Xuan Son and Kieu Ki was 3468, 227 and 118 tons per day
respectively. The preferably recycled waste was collected through many activities
of including mostly junk-shops and waste pickers on street as well as landfills.
The percentage of waste recycled was at about 10% of total waste generation(MONRE, 2011), mainly recovered in some recycling villages which are privateand small producers, as a result it was difficult to determine the amount ofrecycled waste exactly.
2.3.2 Waste stream calculation
The study was applied MFA approach to calculate the amount of waste recoveredfrom landfills (Gtc-BCL), as following equations
Gtc  BCL  Gtc  10% xGktg    Gtc ,i    Gi NS   Gi XS   Gi KK   (t/d) (1)
i
i
 i

 i
Where,- Gktg, the total amount of household waste was not collected (t/d);- Gtc ,i , the total amount of recyclable waste generated within the city,
Gtc ,i  ri NT  G NT  ri NgT  G NgT (t/d)(2)+ ri NT , ri NgT , the percent of recyclable waste i generated in urban and countryside;+ G NT , G NgT : the total amount of waste in urban and countryside was 4100 and
2400 t/d respectively;- Gtc, the total amount of waste recycled of the city in 2011, accounted for 10% of
the total generation (MONRE, 2011), Gtc  10%  6500  650 (t/d);522

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ICUS Report 73- GiNS , XS ,KK , the amount of recyclable waste i transported to Nam Son, Xuan Son
NS , XS , KK
 ri NS , XS ,KK (t/d)
and Kieu Ki landfills, GiNS , XS ,KK  GCL(3)

NS , XS , KK
CL

, the total amount of waste transported to Nam Son, Xuan Son, Kieu
+G
Ki landfills;+ ri NS , XS , KK , the percent of recyclable waste type i such as paper, metal, plastic…
transported to Nam Son, Xuan Son, Kieu Ki landfills;- the term   Gtc ,i    Gi NS   Gi XS   Gi KK   presented the amount of
i
i
 i

 i
(4)
recyclable waste recovered outside landfills (t/d)
The amount of recyclable waste type i landfilled was accounted as difference
between amount of waste i transported to landfills and that of i recovered fromlandfills. An assumption is made that percentages of recyclable waste recoveredfrom landfills including paper, metal, plastic and nylon are equal. The amount ofother waste landfilled in 2011 was calculated by their percentages in table 2.
2.4 Estimation of GHG emission from treatment facilities
2.4.1 CH4 emission from landfills
The study propose to use 2006 IPCC guideline – model Tier 2 (IPCC, 2006) for
estimating methane emission from landfills. The input data of composition ofwaste landfilled was used are the results from waste material flow analysis as well
as some defualt parameters suggested by IPCC (presented in Table 3). In order tocalculate the direct CH4 emitted from landfilling the amount of household solid
waste in 2011, author assumed that landfills in Hanoi operated within 1 year andclosured in the end of 2011 when completed the treatment for the waste of 2011.
The CH4 emissions from solid waste disposal for a single year can be estimatedusing the general Equations 5. Part of the CH4 generated is oxidized in the coverlayer, or can be recovered for energy or flaring. The CH4 actually emitted fromthe landfill will hence be smaller than the amount generated (IPCC, 2006).


LCL CH 4    (CH 4 gen ,i ,T  RT )   (1  OX T ) (thousand tons) (5) iWhere:LCL CH 4 , CH emitted in year T, (thousand tons);
RT, recovered CH4 in year T (thousand tons);
T, inventory year ;OXT, oxidation factor in year T, (fraction);

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Table 3. Default parameters used in IPCC model

DOC (% wet
waste)
Organic waste
Paper
Wood
TextileDOCf (%)
K (Year-1)
Organic waste
Paper
Wood
Slowly degradingorganic waste
Delay time(month)F
Oxidation factor
MCF

IPCC
default

Used

0.08-0.20
0.36-0.45
0.39-0.46
0.20-0.40

0.15
0.4
0.43
0.24

0.5
0.17–0.7
0.06–
0.085
0.03–0.05
0.15–0.2

0.4
0.07
0.035
0.17
6
0.5
0
0.6

Explaination
Degradable organic carbon (DOC) is the organiccarbon in waste that is accessible to biochemical
decomposition. The DOC in bulk waste is estimatedbased on the composition of waste and can becalculated from a weighted average of the degradable
carbon content of various components (waste types) of
the waste stream.
Fraction of degradable organic carbon (DOCf) is an
estimate of the fraction of carbon that is ultimately
degraded and released from landfill.
The reaction constant k =ln(2)/t1/2, where t1/2 is halflife-time, which depended on various factors including
mostly climate conditions factors. With MAP>1000m,
The climate of Vietnam is moist and wet tropical.
Delay time should not be chosen more than 6 months
according to IPCC suggestion.
Methane fraction in LFG
Methane correction factor. With landfills in Hanoi,
author chose as Semi-aerobic managed solid waste
disposal sites

2.4.2 GHGs emission from composting facilities

Composting is an aerobic process and a large fraction of the degradable organiccarbon (DOC) in the waste material is converted into CO2. CH4 is formed inanaerobic sections of the compost, but it is oxidized to a large extent in the
aerobic sections of the compost. This process also emitted N2O and acounted forabout from 0,5% (Beck-Friis et al., 2001) to 5% of total nitrogen in solid
waste.Thus, according to 2006 IPCC guidelines, the study used default CH4 andN2O emission factor at about 4gCH4 per 1 kg waste and 0,3gN2O per 1 kg waste
respectively.
2.4.3 Global warming potential

The Global warming potential (GWP) provides a metric for evaluating andcomparing the potential climate change associated with emissions of different
GHGs (Scheutz et al., 2009). The IPCC provides the GWP for a time horizon of20, 100 and 500 years, but a time horizon of 100 years is employed mostcommonly (Forster, 2007). According to Fuglestvedt et al. (2001) the choice oftime horizon depends on the policy objective. This study adopted the 100 years
horizon with GWP of CH4 and N2O equal to 25 and 298 respectively suggested by
Forster (2007) in order to determine the maximum change in climate.

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3. RESULTS AND DISCUSSION
3.1 Waste material flow analysis

The amount of recyclable waste recovered outside landfills is determined by theequation 4 and it equal to 1036 – 780 = 256 tons per day, where 780 is amount ofrecyclable waste transported to landfills (in equation 3). Thus, the amount ofrecyclable waste recovered from landfills, determined by equation 1 is 277.5 tons
per day.
Within landfills in Hanoi city, activities of waste recovery of waste pickers andjunk-mans contributed an amount of 277.5 tons recyclable waste a day. In
addition, debris material released from composting plants and recycle village ofabout 55.55 (35% mass of organic waste input) and 65 tons per day (10% mass ofrecycle waste input) respectively (MONRE, 2011), was landfilled likewise. Thus
the actual total amount of waste landfilled daily was 3656 tons and thepercentages of recycled paper, plastic and nylon, metal in Hanoi in 2011 was 36%,
53% and 79,64%. Figure 1 describes the waste material flow in 2011 of Hanoi andthe table 4 illustrated waste stream information of comparative scenarios.

Figure 1. Waste material flow analysis in 2011 of Hanoi
Table 4. Waste material flow analysis for scenarios
Scenarios

Compost(tons/day)Landfill(tons/day)

HT
S1
S2

159
2903
2903

3656
3141
3141

Percentage of different waste landfilled
Organic
Paper
Textile Wood
Others56,65%
4,32%
5,77% 2,94% 30,32%
0
1,57%
4,23% 5,65%
88,5%
0
1,57%
4,23% 5,65%
88,5%

Recycle(tons/day)Untreated(tons/day)

650
829
829

2155,500Assessment of potential greenhouse gas emission of domestic solid waste treatment inAssessment ofHanoi,
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3.2 GHG emission from treatment facilities
3.2.1 CH4 emission from landfills

Organic the waste, paper, wood and textile are the main sources of CH4 emission
in landfills. The figure 2 illustrated the potential quatity of CH4 emissiom ofabove types of waste. Results showed that the capacity of CH4 emission are
different from various waste and organic waste contributed the largest propotionof 70%, followed by paper with the percentage of approximately 17%. The
smallest contributer in landfill is wood accounted for about 14% of total CH4
emitted from landfills.
The CH4 emission factor waste presents the amount of CH4 released per 1 ton ofthat kind of waste landfilled. That of textile and paper waste was very high at
around 90 kg CH4 per tom of waste treated. On the other hand, the CH4 emission
factor of organic waste was smallest though that is the largest source of CH4
emission from landfills.

Figure 2. CH4 emission from landfills of different materials
3.2.2 GHGs emission from composting plants

Results of CH4 and N2O emission from composting facilities and there GWP100
were summarized in the Table 5.
Table 5. Quantity of GHG emission from composting

GHG

Total organic
waste, 2011

(thousands ton)
58,04
CH4
58,04
N2O
Total GWP100

526

EmissionfactorAmount

GWP100(g/kg)
4
0,3(tons)
232,14
17,41(tons CO2 -eq)
5803,55188,33
10 991,7

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3.2.3 Potential GHG emission and mitigation

The total potential amount of GHG emission from treatment of household solid
waste generated in 2011 in Hanoi city is the sum of nearly 100 years of emission.
As a result, the potential the total amount of GHG emission from treatment
facilities in Hanoi was approximately 855 thousand tons CO2-eq, landfills
accounted for 99% and made a contribution of 845 thousand tons CO2-eq.
The GHG emission of comparative scenarios S1 and S2 was 426 and 386
thousand tons CO2-eq respectively. It means these scenarios contributed to GHG
emission mitigation which was calculated as a comparison between the GHG
emission and the GHG of current status emission. Figure 3 presented the GHG
emission of scenarios. It is shown that GHG emission reduction can reach up to
about 60% when use scenarios S1 or S2. The results showed that scenario S2 was
the most GHG emission mitigation practice due to applying LFG recovery
technology.

Figure 3. GHG emission and reduction

4. CONCLUSIONS

Result of waste flow analysis in 2011 of Hanoi showed that there were a greatamount of waste untreated, 2100 tons per day. That reflected accurately the low
efficient solid waste collection system of the city.
The result of this study also certified the importance of separation at source andrecycling practices including composting in order to avoiding landfilling organic
waste and others emitted CH4. Hargreaves et al. (2008) reported that organic
waste composting had a potential as a beneficial recycling tool for waste
management and treatment. Furthermore, this method reduced the volume ofwaste which goes to landfill and the production appropriated for applying
agriculture fields as safety fertilizer as well as avoiding biogenic CO2 emission bylong time C storage in soil (Boldrin et al., 2009).
Assessment of potential greenhouse gas emission of domestic solid waste treatment inAssessment ofHanoi,
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REFERENCES

Beck-Friis, B., Smars, S., Jönsson, H., Kirchmann, H. (2001) Gaseous emissionsof carbon dioxide, ammonia and nitrous oxide from organic household waste in acompost reactor under different temperature regimes. Journal of agricultural
engineering research 78, 423-430.
Boldrin, A., Andersen, J.K., Møller, J., Christensen, T.H., Favoino, E. (2009)
Composting and compost utilization: accounting of greenhouse gases and global
warming contributions. Waste Management & Research 27, 800-812.
Forster, P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D.W. Fahey, J.
Haywood, J. Lean, D.C. Lowe, G. Myhre, J. Nganga, R. Prinn, G. Raga, M.
Schulz and R. Van Dorland, (2007) Changes in Atmospheric Constituents and in
Radiative Forcing, in: Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis,
K.B. Averyt, M.Tignor and H.L. Miller (Ed.), Climate Change 2007: The PhysicalScience Basis. Contribution of Working Group I to the Fourth Assessment Reportof the Intergovernmental Panel on Climate Change. Cambridge University Press,
Cambridge, United Kingdom and New York, NY, USA.
Fuglestvedt, J.S., Berntsen, T., Godal, O., Sausen, R., Shine, K.P., Skodvin, T.
(2001) Assessing the metrics of climate change: current methods and future
possibilities. Report/CICERO-Senter for klimaforskning.
Gentil, E., Christensen, T.H., Aoustin, E. (2009) Greenhouse Gas Accounting andWaste Management. Waste Management & Research 27, 696-706.
Hargreaves, J.C., Adl, M.S., Warman, P.R. (2008) A review of the use ofcomposted municipal solid waste in agriculture. Agriculture, Ecosystems &Environment 123, 1-14.
HSO, (2011) Hanoi Statistical Year book 2010, in: Office, H.S. (Ed.). Statistic
Publisher, Hanoi, Vietnam.
IPCC (2006) 2006 IPCC Guidelines for National Greenhouse Gas Inventories Vol 5: Waste. IPCC National Greenhouse Gas Inventories Programme, Institutefor Global Environmental Strategies (IGES), Hayama, Japan.
ISWA, (2010) ISWA White Paper: Waste and Climate Change, in: Gary
Crawford, C.F., Jens Aage Hansen, Antonis Mavropoulos (Ed.). International
Solid Waste Association, Vienna, Austria.
JICA, (2011) Report on solid waste management research in Vietnam 3/2011
Hanoi, Vietnam.
MONRE, (2011) Nationa Report on Environment 2011: Solid Waste, in:Environment, M.o.N.R.a. (Ed.). Ministry of Natural Resource and Environment,
Hanoi, Vietnam.
Savino, A.A. (2009) Editorial. Waste Management & Research 27.
Scheutz, C., Kjeldsen, P., Gentil, E. (2009) Greenhouse gases, radiative forcing,global warming potential and waste management — an introduction. Waste
Management & Research 27, 716-723.
UNEP (2010) Waste and Climate Change: Global trends and strategy framework
UNEP, Osaka/Shiga.
URENCO, (2011) Solid Waste Report. Hanoi urban environment one member
limited company, Hanoi, Vietnam.

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Optimisation of indoor environmental quality
and energy consumption
within urban office buildings
Tran Ngoc QUANG
Department of Building Service Engineering and Built Environment
National University of Civil Engineering, Hanoi, Vietnam
tnq.qut@gmail.com
ABSTRACTThis paper summaries the author’s PhD work, which has been conducted in
Brisbane, a capital city of the State of Queensland, Australia. The research aimed
to investigate particle characteristics and dynamics inside and around officebuildings, together with their relationship to one another and the factors which
affect them. Based on the above, a multi-component model, including indoor
particle number (PN) model, was developed and applied to optimise indoor
environmental quality and energy consumption in office buildings. The significant
contributions of this study include: (i) an improved understanding of particle
characteristics (particle number size distribution - PNSD and PM2.5) aroundbuilding envelopes under the influence of vehicle emissions and nucleation events;(ii) an improved understanding of indoor particle characteristics and dynamics
inside mechanically ventilated office buildings; (iii) acknowledgement of the roleof nucleation events in producing particles, and their influence on urban
environment (this is the first time that the effect of new particle formation on thevertical profiles of particle concentrations around building envelopes and PN
concentration inside office buildings has been identified and quantified); (iv) the
first multi-component model consisting of indoor PN and CO2 concentration,
thermal comfort and energy usage, which can be applied to optimise HVAC
systems in mechanically ventilated office buildings; and finally (iv) provision ofscientific and practical information on which to base the selection, location andoperation of filters and outdoor air intakes in a building’s HVAC system, in orderto optimise its operation, in terms of energy conservation and improvements inindoor environmental quality.
Keywords: ultrafine particle, particle number (PN), particle number size
distribution (PNSD), vehicle emission, nucleation event, multi-component model
1. INTRODUCTION
In most urban environments, vehicle emissions and new particle formation are thedominant source of outdoor particles ((Perez et al., 2010; Pey et al., 2008; Shi etal., 2001; Shi and Harrison, 1999; Shi et al., 1999; Wahlina et al., 2001) and(Cheung et al., 2011; Cheung et al., 2012; Pey et al., 2009), respectively).

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VietnamAmbient air quality legislation regulates airborne particulate matter, in terms ofparticle mass concentration, expressed as PM2.5 and PM10 (mass concentrations ofparticles smaller than 2.5m and 10m respectively), and to date, these are also
the most common parameters measured for research purposes. However, themajority of particles emitted by vehicles, in terms of number, belong to theultrafine size range (UF < 0.1m). UF particles contribute very little to PM2.5 andPM10, however they contain the majority of toxins emitted by combustion
sources. Epidemiological research has consistently shown an association between
fine (< 2.5 µm; PM2.5) particle concentrations and increases in both respiratory
and cardiovascular morbidity and mortality (Davidson et al., 2005; Pope, 2000;
Schwartz and Neas, 2000). The health effects of UF particles are less wellunderstood, however recent research indicates that they may be equally or moredetrimental than those of PM2.5 and PM10 (Franck et al., 2011; Oberdorster, 2000).
Significant population growth and urbanisation has been experienced by mostlarge cities in the world, including capital cities in Australia, where population
growth was by 17% between 2001 and 2011, faster than the remainder ofAustralia (11%) (Statistics, 2011).New approaches to land and urban planning areneeded in order to accommodate significant population growth, however suchapproaches, which include transit oriented urban development, can increase thenumber of public and residential developments located close to transport corridors.
Given that outdoor particles can penetrate the building envelope via doors,
windows, building structure leakages and mechanical ventilation systems, theexposure of building occupants to outdoor particles is on the rise.
In Australia, most public buildings are equipped with mechanical heating,ventilation and air conditioning systems. The function of these systems is toremove pollution generated indoors from the indoor environment, to filter outdoor
air supplied to the building, and to provide the required thermal comfort
conditions within the building. However, mechanical ventilation systems always
require considerable amounts of energy to operate. Many efforts have been madeto optimise building HVAC systems, however most studies have focused onindoor thermal comfort and energy consumption (e.g. Al-Sanea and Zedan (2008),
Chowdhury et al. (2008), Freire et al. (2008), Taylor et al. (2008), Conceição et al.
(2009)). Some studies also considered indoor air quality, but only indoor CO2
concentration was taken into account (Atthajariyakul and Leephakpreeda, 2004;
Congradac and Kulic, 2009; Kavgic et al., 2008; Mathews et al., 2001; Nassif etal., 2008; Wong et al., 2008a; Wong et al., 2008b).
An urban environment is characterised by the presence of a large number of roads,
bordered on either side by buildings of various sizes. Changing building heights
and small local structures in street canyons can generate very complex wind
patterns and turbulence, which result in localised areas that experience low wind
flow. Vehicle movement, together with wind induced turbulence and efficient
mixing, can lead to inconsistencies in the vertical profile of particle concentrations
around building envelopes, which has been reported regularly in scientific
literature.

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The contribution of outdoor and indoor particle sources to the concentration ofindoor particle varies and depends on many factors, including the type of particle
source, air exchange rate in the building and the type of filters used. Besides
dominant outdoor sources in the urban environment consisting of vehicle
emissions and new particle formation, printing and vacuum cleaning wererecently reported as the main sources of indoor particles in office buildings.
Ventilation systems that utilise filter media can reduce indoor particle levels
which originated from both outdoor and indoor sources. However, information on
the impact of such systems on indoor particle concentration, especially fine andUF particles in office buildings, is very limited.
Given that fine and UF particles are ubiquitous, emitted from both indoor andoutdoor sources and can be toxic to human health, they could be considered justas, or even more dangerous than many other indoor pollutants. However, due to alack of information regarding the characteristics and dynamics of particles in andaround office buildings, fine and UF particle concentrations have yet to beconsidered in the optimisation of building HVAC systems.
The main goal of this research project was to develop a tool that will allowbuilding designers and managers to maximise indoor environmental quality while
minimising energy consumption to provide better indoor office environments inorder to protect the health of building occupants within office buildings located inhigh outdoor particle concentration areas. The following specific objectives were
implemented to achieve the study goal: (1) Assess the variation of PNSD, PN andPM2.5 concentrations at the rooftop and street levels of three urban officebuildings located close to busy roads in Brisbane, Australia; (2) Quantify verticalprofiles of PNSD and PM2.5 concentration around these buildings and analyse theinfluence of vehicle emissions and nucleation events on these vertical profiles; (3)Quantify and interpret differences between PNSD and PM2.5 concentration at
different levels around these buildings; (4) Determine indoor and outdoor particle
concentrations in these buildings; (5) Quantify the in-situ efficiency of different
filter types in these buildings; (6) Assess the impact of ventilation systems using
these filters on indoor particle levels under the influence of different indoor andoutdoor particle sources; (7) Adopt, validate, assess and apply an existing
dynamic indoor particle number concentration model to evaluate their importantfactors affecting indoor particle levels; (8) Develop a multi-component model forthe optimisation of indoor air quality, thermal comfort and energy consumption;and (9) Apply the multi-component model for assessing indoor air quality andenergy usage in mechanically ventilated office buildings.
2. SUMMARY OF THE RESEARCH METHODS
The research was conducted in the subtropical city of Brisbane, which is thecapital city of Queensland, Australia. Three urban office buildings, located close
to busy roads with different terrains, heights, and mechanical ventilation systems,
were selected.

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VietnamTwo sets of instruments including TSI 3934 Scanning Mobility Particle Sizer(SMPS), TSI 3781 Condensation Particle Counter (CPC), and TSI 8520 DustTrak
aerosol monitor, were used to simultaneously measure PNSD, PN, and PM2.5
concentrations, respectively at different levels surrounded building envelopes, andat upstream and downstream of central plant room filters at all three buildings.
At the same time, other set of instruments including TSI 3025 CPC, TSI 8520
DustTrak, and TSI 8552 QTrak, were used to measure indoor air quality,
consisting of PN, PM2.5, CO2, CO, Temperature, and Relative Humidity,
respectively.
Relevant meteorological parameters and traffic densities were obtained from the
Queensland Bureau of Meteorology weather station located in Brisbane CBD andQueensland Department of Transportation, respectively.
An existing indoor particle concentration model was modified, validated to model
indoor particle concentrations under different sources and ventilation scenarios.
An indoor CO2 concentration model was also developed to integrate with theindoor particle concentration model to optimal outdoor ventilation rates.
Finally, an HVAC energy consumption model related to outdoor air ventilation
was built up based on the optimal outdoor ventilation rates and optimal indoor
thermal comfort.
All statistical analyses (correlation, regression, t-test, One-Way ANOVA, …)
were conducted using SPSS for Window version 18 (SPSS Inc.). The 5% level
was used to indicate statistical significance in all cases.
The detail description of the research methods is provided in the author’s journal
papers (Quang et al., 2013a; Quang et al., 2012; Quang et al., 2013b).
3. SUMARY OF THE MAIN STUDY RESULTS AND DISCUSSION
In the first paper (Quang et al., 2012), the vertical profiles of particle
concentrations around three office buildings in Brisbane were quantified and theinfluence of vehicle emissions and new particle formation were determined. The
major findings of this work are summarised below.
As expected, vehicle emissions strongly influenced both PN and PM2.5
concentrations at both street and roof levels, especially during rush-hours at all
three buildings. Similarly, building topography, distance from the emission
sources, and wind speed and direction also had an observed effect on particle
concentrations at the three buildings.
On the other hand, new particle formation events were found to influence andcontribute to increases in PN concentrations at both rooftop and street levels at all
three buildings. However, the factors that contributed to the observed phenomena

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were different between buildings. For those buildings close to busy roads, the newparticles were mainly formed from local vehicle emissions and therefore, theformation process was expected to depend mainly on local conditions, such as
high condensable gas concentrations and solar radiation intensity, together withlow pre-existing particle concentrations. Meanwhile, for buildings where the
newly formed particles were blown in from the direction of a nearby industrial
zone, new particle production was not the result of local sources but was strongly
influenced by wind speed, wind direction and the origin of incoming air masses.
Therefore, all of these factors need to be undertaken into consideration prior tomodelling urban canyon particle profiles and concentrations, and a ‘one-size-fitsall’ approach is unlikely to be able to account for the specific determinants at eachindividual building. In addition, nucleation events are often studied in the context
of their role as physical phenomena, and typically within the context of producing
natural and anthropogenic aerosols that may affect climate change. This study has
shown that the typically under-valued role of nucleation can produce particles that
can affect large numbers of people, due to the high density and occupancy ofurban office buildings and the fact that the vast majority of people’s time is spentindoors.
The vertical profiles of PM2.5 concentrations around building envelopes were
found of decreasing concentrations with increasing height. However, verticalprofiles of PNSD were building-specific and the rate of change with height wasdifferent at all three buildings. The results indicate that it is not only vehicle
emissions that influence particle vertical profiles, but new particle formation as
well, with both increases in particle number and a reduction in particle massobserved during nucleation events. These results serve to further define thespecific effect of roadway proximity and nucleation formation on the verticalprofiles of PN and PM2.5 concentrations around building envelopes. Moreover,the highly building-specific nature of these profiles and factors affecting them,
indicate that measurements should form the basis of any modelling or planning
exercise prior to or after the construction of a new building. Such an approach,which is currently lacking for the most part, will ensure the greatest reliability.
This has important implications for selecting appropriate sites for the air intakesof building HVAC systems, in order to minimise occupant exposure to
combustion products and also to investigate how street-level exposures may be
mitigated via improved design practices.
Correlations between PNSD and PM2.5 were characterised by a significant
variability and dependence on particle size fraction, measured height and particle
emission sources. The linear correlations for the building envelopes, especiallyduring rush-hours and nucleation events, varied fluctuated significantly. This
indicates that it is not appropriate to use particle mass concentrations to infer PN
concentrations when modelling vertical concentrations around the building
envelope and at a street level. This finding, while not a novel observation, adds
weight to the existing case for considering particle mass and number separately
during any urban modelling or exposure assessment exercise.
In summary, vertical profiles of PM2.5 concentration around building envelopes
showed a consistent decrease in concentration with increasing distance from
Optimisation of indoor environmental quality and energy consumption within urban
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October
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Vietnamnearby streets. However, vertical profiles of PN size fraction concentrations werebuilding-specific and its rate of change was inconsistent with height. These results
were not unexpected, in view of the complex flow patterns around the building
envelopes, as well as in the busway and street canyons that were proximate tosome of the buildings. The results of simultaneous measurements indicated that itwas not only vehicle emissions, but also new particle formation that influenced
the vertical profiles of particle concentrations. Time series ratios of PN and PM2.5
concentrations at street and rooftop levels showed clear diurnal variation, whichsuggests that it is impossible to generalise vertical profiles of particle
concentrations for all buildings, and that there is a need to conduct measurements
or model these vertical profiles for a specific case when planning building
morphology and air intake locations. Furthermore, newly formed particles andbuilding-scale variability should also be taken into account when modelling
particle concentrations around the building envelope, and also for urban
environments and the exposures that occur within them.
The results of this work serve to provide better insight into the impact of
nucleation and local scale variability on particle concentrations, and will also help
to better define particle behaviour and variability around building envelopes,
which has implications for studies of both human exposure and particle dynamics.
The influence of ventilation and filtration on indoor particle concentration within
office buildings located close to busy traffic areas was reported in the second
paper (Quang et al., 2013a). The findings and their implications can besummarised accordingly.
The average indoor PN and PM2.5 concentrations were (2.46 – 5.71) ×103 p cm-3
and 5.2 – 6.81 µg m-3, respectively, and the average outdoor PN and PM2.5
concentrations were (8.94 – 17.4) ×103 p cm-3 and 9.25 – 13.9 µg m-3, respectively,
for the three buildings. The significantly higher indoor and outdoor particle
concentrations for Building A compared to Buildings B and C were due to theproximity of this building’s air intakes to a strong outdoor particle source (i.e.
busway). This suggests that the location of the HVAC system’s outdoor air
intakes can significantly reduce the impact of outdoor particles on indoor air.
The in-situ efficiency of deep bag (DB) filters ranged from 26.3 to 46.9% for thethree buildings, while the efficiency of the electrostatic (ES) filter in Building C
was 60.2% and the efficiency of the fan coil unit (FCU) filter in Building A was
21%. The results show that the efficiency of the DB filters was strongly affectedby particle characteristics, in particular particle size and particle upstream
concentration. The efficiency of the ES filter was lower than those tested in thelaboratory, which could be due to the different operating conditions and upstream
particle characteristics between the real-world and laboratory environments.
However, this work only measured one ES filter in one office building andtherefore, further investigations into in-situ ES filter efficiency under different
conditions is recommended. Additionally, the overall filtration efficiency of the
FCU filter was significantly lower than those applied in the central plant rooms.
This result strongly suggests that a better filter needs to be used for the FCU, inorder to clean outdoor air, if it contains high particle concentrations.

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The I/O particle concentration ratios showed that mixing air filters not only
prevent outdoor particles penetrating indoors, but they also reduce the impact ofindoor particle sources on indoor particle concentrations. On the other hand, theutilisation of both outdoor and mixing air filters can significantly reduce and keep
indoor particle concentration lower when compared to the use of only mixing air
filters.
Based on the comparison of I/O particle concentration ratios and their I/Ocorrelation during rush-hours, nucleation events and overall working-hours, theresults indicate that indoor PN concentration was strongly influenced by outdoor
PN concentration during rush-hours and nucleation events. Many studies haveinvestigated new particle formation and its effect on regional environments or
climate change, but they are yet to focus on indoor environments, especially officebuildings. Once again, this work draws attention to the under-valued role ofnucleation in generating particles that can penetrate inside buildings and affectlarge numbers of people, due to the high density and occupancy of urban officebuildings.
A previously reported dynamic model for indoor PN concentration was modified,evaluated and applied to assess the influence of the filtration/ventilation systems
on indoor particle levels under different indoor and outdoor particle source
conditions. The results of the 24 h modelling indicated that the model performed
very well when outdoor air was the main source of indoor particles, with lessuncertainty for indoor source emissions, or when the ventilation system wasturned off. These results also highlighted the fact that the filtration of both mixing
air and outdoor air can significantly reduce indoor particle levels.
These findings provide scientific grounds for the selection and location of
appropriate filters and air intakes in building HVAC systems, in order to minimise
occupant exposure to high outdoor particle concentrations from combustion
products and new particle formation. The results also serve to provide a better
understanding of indoor particle dynamics and behaviours in office buildings,
under different ventilation scenarios.
Based on the findings of the first and second papers, a multi-component model
was developed, in order to optimise indoor environmental quality and energy
consumption in mechanically ventilated office buildings located close to highoutdoor PN concentrations originating from vehicle emissions and/or new particle
formation (Quang et al., 2013b). Indoor PN and CO2 concentrations, and energy
usage were evaluated under different operation modes, for optimal indoor
temperature settings (according to a survey of building occupant preferences)during summer and winter. It was found that indoor air quality and potential
energy savings increased significantly when the ventilation system as operated
according to optimal operation modes compared to the normal modes used during
the summer and winter months. If combined with other building thermal load
components, the model will become more comprehensive and highly effective forthe simulation and operation of HVAC systems to maximise indoor air quality and

Optimisation of indoor environmental quality and energy consumption within urban
office buildings
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October
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Vietnamminimise energy consumption within office buildings located close to busy traffic
areas.
4. CONCLUSIONSThis is the first time that the influence of new particle formation on the particle
concentrations around the building envelopes and inside the office buildings has
been identified and quantified. This research developed the first multi-component
model consisting of indoor PN and CO2 concentrations, thermal comfort andenergy usage, and it can be applied to optimise building HVAC systems. Overall,this study not only improves scientific understanding and knowledge regarding
the characteristics and dynamics of particles around and inside office buildings,
but also provides scientific and practical information for the design, upgrading
and operation of HVAC systems in mechanically ventilated office buildings.
ACKNOWLEGEMENT
The author would like to express his sincere appreciation and gratitude to his
principal supervisor, Professor Lidia Morawska, for her continuous advice,suggestions and encouragement throughout the course of this study. Without her
close supervision, this study would have never come to fruition. The author
expresses his profound gratitude to his co-supervisor, Dr Congrong He, for his
constructive comments and valuable suggestions during the course of this research.
The author is also grateful to the Queensland University of Technology (QUT) for
providing a tuition fee waiver scholarship, together with the Vietnamese
Government, the School of Physical and Chemical Sciences, QUT and theInternational Laboratory for Air Quality and Health - ILAQH, QUT for providing
living allowance scholarships.

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A basic study on future strategy
for effective disaster information
dissemination: Case study in Thailand
Niwat APICHARTBUTRA1, Miho OHARA2
1

Doctor Course Student, Department of Civil Engineering,
Graduate School of Engineering, the University of Tokyo, Japanniwat-a@iis.u-tokyo.ac.jp
2
Associate Professor, International Center for Urban Safety Engineering,
Institute of Industrial Science
The University of Tokyo, Japanohara@iis.u-tokyo.ac.jp
ABSTRACT
Information Dissemination is considered as one of the most important tools to
disaster risk reduction; yet, if poorly managed, it can pose hindrances to disastermitigation process. This paper examines disaster information dissemination
system in Thailand. It intends to investigate how disaster-related information was
disseminated during Thailand’s most extensive inundation in 2011; and, attempts
to draw recommendations. During the flood, the Thai government tried toestablishment disaster information communication with the people. However, its
attempt was not successful. This led to frustration of a majority of Thai people
and, in turn, triggered a momentum of information flow in various forms andmeans of informal communication. In the latter part of this report strategies for
effective disaster information dissemination are also proposed in a 3-tiered
framework.
Keywords: disaster information dissemination, Thailand flooding 2011
1. INTRODUCTION
In July 2011, Thailand was hit severely by the build-up of waters brought
by a 25% increase in average season rainfall. The inundation later spread throughprovinces of the Northern, North-Eastern and Central Thailand along the
Mekhong and the Choa Phraya river basins and became the country’s mostextensive inundation in 70 years. The flood claimed more than 600 lives; and theWorld Bank (2011) estimated economic losses were at 45.7 billion USS. Due tothe exorbitant lost, there were a number of evidence pointing that Thailand was
unable to deliver effective disaster information to the people, which led to poor
management of the flood and an urgency to develop a comprehensive framework
to manage disaster. (Larnard and Sandman, 2011; Coben, 2011; Reuters, 2011;
Bangkok Post, 2013)541

October
2013, 2013,
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VietnamFlood risk communication studies have been carried out extensively in the
US and Europe as one of the most important tools to disaster risk reduction. (ColeT.W. and Fellows K.L, 2008; Tinker T.L. and Galloway, Jr. E.G., 2009; Bradfordand O’Sullivan, 2011) In case of Thailand, however, there is a limited number ofstudies carried out in terms of flood disaster information dissemination during theworst flood in 2011. Therefore, this paper intends to investigate how disasterrelated information was disseminated during Thailand’s most extensive
inundation in 2011. It focuses on disaster information dissemination in Thailand;and, attempts to draw recommendations. In this study, strategies for effective
disaster information dissemination are also proposed.
2. THAILAND’S 2011 FLOOD DISASTER INFORMATIONDISSEMINATION
To investigate disaster information dissemination during the 2011 flood,
this report employs documentary research methodology and breaks lines ofcommunication during Thailand’s 2011 inundation into 2 periods using October 8,
2011, as the breakpoint because October 8, 2011, was when the Prime Minister ofThailand ordered a setup of Flood Relief Operations Centre (FROC) as the “onestop service” for flood-related matters including information and warning
dissemination. The 2 periods comprises (1) Thailand’s disaster information
dissemination before October 8, 2011, and (2) Thailand’s disaster information
dissemination after October 8, 2011.
2.1 Thailand’s disaster information dissemination before October 8, 2011
According to the National Disaster Prevention and Mitigation Plan B.E.
2553-2557 (2010-2014), Thailand’s latest disaster prevention and mitigation
scheme, general requirements have been introduced for effective disaster
information dissemination. The following government agencies responsible fordisaster information dissemination have to make notifications.
 Thai Metrological Department (TMD) and National Disaster Warning
Center (NDWC) are responsible for close surveillances and warning at
national level.
 Department of Disaster Prevention and Mitigation (DPM) receives
warning information from TMD and NDWC and some relevant
agencies and further disseminates warning information to the provincial
government.
 Provincial government is responsible for the watch-out anddissemination of warning information at provincial level.
 District office is responsible for surveillance and dissemination of
warning information at district level.
 Civil Defense Volunteer and warning information dissemination
network are responsible for surveillance and dissemination of warning
information at community level.

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2.2 Thailand’s disaster information dissemination after October 8, 2011
On October 8, 2011, the Prime Minister of Thailand set up the Flood
Relief Operations Centre (FROC) in an effort to solve floods in a coherent andcomprehensive manner. One of FROC main duties was to be the center of floodrelated information to send out important information to people such as situation
evaluation and warning. The Justice Minister was appointed to take charge FROC
along with the Interior Ministry’s Deputy Permanent Secretary. The Science andTechnology Minister was put in charge of operations. The Transport Ministermanaged FROC’s information and public relations. Governors of local entities
were to follow FROC’s orders in managing the floods in their respective localities
and encouraged to set up provincial versions of FROC. The armed forces as wellas other governmental agencies were to take orders from the Prime Minister’s
Office. Later in October 20, 2011, the Prime Minister invoked Section 31 of the2007 (B.E. 2550) Disaster Prevention and Mitigation Act which gave the prime
minister a single control to all officials.
In the setup day, FROC was assigned as the focal point to disseminate
disaster information to people. Apart from regular announcement through mass
media, FROC opted to send information in short messages (SMS) through mobile
phone. It appointed the National Broadcasting and Telecommunications
Commission (NBTC) to look after the task. NBTC summoned ad hoc cooperation
with the 3 major mobile phone network carriers in Thailand, namely AIS, DTAC,
and TRUE.
The Government would like tosend information from the
Flood Relief Operations Centre(FROC) through SMS.
Volunteers are invited at
FROC, 1st floor, Don Muang
Airport. Everyday from8.00-21.00 hrs.
Now FROC successfully
controlled water in Prapa
canel.
FROC has already ordered
the Bangkok Metropolitan toimmediately drain flood waterin Don Muang and Laksi.

Table 1 : The 4 short messages sent by FROC
Unfortunately, FROC did not mount a united front in its management of
the floods crisis and lost its credibility. (Chinchit, 2011) The FROC’s chief often
gave contradictory statements to the media, issued a false sense of confidence tothe public and, most importantly, delivered irrelevant information that people did
not really need. (Thairath, 2011) Its first SMS was released on October 11, 2011
and the last one was reported to be received on the October 23, 2011. Altogether,
it was reported in Thairath newspaper (2011) that there were 4 messages sent by
FROC and the people were not satisfied with the content of them because they did
not serve the purpose of early warning and evacuation. Figure 1 shows the 4messages with translation. On October 24, 2011, FROC officially announced thatit had stopped sending SMS to the people by giving the reasons that “sending
information via SMS messages is limited to 70 alphabets. The limitation would
cause messages confusing and subjected to people’s interpretation.”
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Matichon Newspaper (2011) reported that Assumption University’s
ABAC Poll Research Centre surveyed 415 people living in Bangkok and adjacentprovinces in October 2011 regarding FROC’s credibility. The survey revealed thatnearly 90 percent of the respondents said they were confused by announcementsfrom FROC. 87% said they did not trust information from FROC and 86% said
FROC did not provide clear information as to whether their homes would be
flooded. They gave average score of 3.36 out of 10.
Now FROC still exists but appears to be inactive under the Ministry of
Natural Resources and Environment.
3. THAI GOVERNMENT AGENCIES RELATED TO FLOOD DISASTERDISSEMINATION
Apart from the aforementioned agencies, there are also a number ofgovernment agencies that routinely take part in disseminating flood information in
Thailand. Some send warning and useful information directly to the people whilesome are in charge of information gathering, monitoring as well as issuing
warning and useful information to concerned agencies. This part of the paper
attempts to gather relevant agencies that disseminate disaster information
particularly flood-related information to the people. Through an observation, there
are 10 following agencies related to flood information dissemination in Thailand.
Ones marked have warning systems.
1. Thai Meteorological Department (TMD)
2. National Disaster Warning Centre (NDWC)
3. Department of Disaster Prevention and Mitigation (DPM)
4. Department of Mineral Resource (DMR)
5. Department of Water Resources (DWR)
6. Department of National Park, Wildlife and Plant Conservation (DNP)
7. Royal Irrigation Department (RID)
8. Hydro and Agro Informatics Institute (HAII)
9. Electricity Generating Authority of Thailand (EGAT)
10. Bangkok Metropolitan Administration
All 10 agencies have established their own means to communicate withthe people mostly through websites and some have certain system that issues
warnings to (1) concerned agencies and/or (2) areas or people that might be at risk.
Table 1 shows agencies that have warning systems, while Table 2 shows agencies
that have monitoring function. To mention some, DPM and DMR haveestablished a network of trained volunteers that can disseminate disaster
information to the local people and collect information from the at-risk sites tosend back to central authorities. DWR has developed early warning systems inlocal areas where sound alarm can be triggered after detecting dangerous level ofrainfall.

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Table 1 : Agencies that have warning systems
Agencies

Issuing warnings
to relevant agencies

Thai Meteorological
Department (TMD)
Department of Disaster
Prevention and
Mitigation (DPM)
Department of Mineral
Resources (DMR)
Royal Irrigation
Department (RID)

Electricity Generating
Authority of Thailand(EGAT)
Thai Meteorological
Department (TMD)

Issuing warning to people

National disasterwarning center(NDWC)

Department of Disaster
Prevention and
Mitigation (DPM)
Department of Mineral
Resources (DMR)

Department of Water
Resources (DWR)

Content of Information

Means of
Warning
Disaster warning
announcement,
SMS
Disaster warning
announcement,
SMS
Disaster warning
announcement,
SMS
Disaster warning
announcement

Weather Forecast by
weather radar andsatellite picture
Disaster information
received from relevant
agencies
Rainfall information,
Geo-hazard and landslide
information
River Water and Rainfall
Information by rain
gauging stations,
Medium- and Large-sized
Reservoir Water Level by
Telemetering system
Dam Water Level by
Disaster warning
Telemetering Systemannouncement
Weather Forecast by
weather radar andsatellite picture
Deep-ocean Assessment
and Reporting ofTsunami (Dart),
Landslide, Disaster
information received
from relevant agencies
Disaster information
received from relevant
agencies
Geo-hazard andlandslide, Heavy rain
warning

Mass media*
Mass media,
Mobile Phone
Application (iOS& Android),
Tsunamiwarning towers
Mass media,
Mr.Warning**
Mass Media,
SMS, Volunteer
Network (13,857
volunteers in 39
provinces),
Village warning
tower
Early Warning
station at risk
areas
Warning throughWebsitePossibility of flood andlandslide (in 1,587 at-risk
villages)
Department ofForest flood and rainfall
National Park, Wildlife information by Rainfall
and Plant Conservation Monitoring Stations in(DNP)
National Conservation
Forests (1,034 stations)*Mass media means making a national broadcast through TV and Radio.
**Mr.Warning is a network of trained community coordinators who givewarning to people as well as monitor and send useful information back to
central authorities.

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Table 2 : Monitoring Agencies
Agencies

Content of Information

Thai Meteorological
Department (TMD)

Rainfall Statistics, Weather
Forecast by Weather Radar,
Meteorological Satellite Picture,
Dam Water Level Data Analysis,
Meteorological Information,
Storm Tracking
Geo-hazard and landslide
information, Rainfall information
Water Level Monitoring by CCTV
(27 sites), Main rivers’ water level
report by remote water-level
gauging stations (114 stations),
Flood and Water Information
through Mekhala (Centre for
Water Crisis)
Rainfall Monitoring Stations in
National Conservation Forests(1,034 stations)

Department of Mineral
Resources (DMR)
Department of Water
Resources (DWR)

Department of
National Park, Wildlife
and Plant Conservation(DNP)
Royal Irrigation
Department (RID)

Hydro and Agro
Informatics Institute(HAII)
Electricity Generating
Authority of Thailand(EGAT)
Bangkok Metropolitan
Administration

Means ofCommunication
WebsiteWebsiteWebsiteWebsiteRiver Water and Rainfall
Information by rain gauging
stations, Medium- and Largesized Reservoir Water Level by
Telemetering system
Information on rainfall and storm
by Mini Telemetering
System/Satellite/Radar
Dam Water Level by Telemetering
SystemWebsiteRainfall Information by radar,water drainage monitored byTelemetering system

WebsiteWebsiteWebsite

4. FLOOD-RELATED INFORMAL COMMUNICATION
Since the government’s attempt to deliver flood information to the people
was not successful, frustration of a majority of Thai people was developed and, inturn, triggered a momentum of information in various forms and means of
informal communication. One of the channels that Thai people favorably opted
for getting information was through the Internet and social networks such as
Facebook, Twitter, YouTube, and Weblog. There were statistics showing a sharp
increase in messages shared through Twitter during flood disaster in Thailand
from 1.5 million messages a day in normal time to about 2.2 million messages a
day during the flood (Bangkok Biz, 2011).
Informal communication during the flood can be grouped into 3
following categories with some examples.
Category I Communication that have already existed before the flood and its
function changed to disseminate flood information.

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ICUS Report 73Seub Nakhasathien, YouTube channel, normally served the purpose ofpromoting forest conservation. During the flood, Sasin Chalermlarp,
Secretariat-General of the foundation, used the channel to broadcast his flood
analysis. The number of accumulative viewers reached almost a million. The
most popular VDO reached 450,000 viewers.
Muang Ake community used its existing platform such as website andFacebook page to communicate with its inhabitants within the community
during flood crisis. Its original function was to share general andadministrative information.

Category II Communication that was created for flood purpose but now inactive
 Roosuflood (know and beat the flood) is a YouTube channel that have anime
VDO concerning how to fight the flood. Some VDO reached more than
300,000 views. The last activity was May 2012.
 ThaiFightFlood, ThailandFlood2011 and NamKunHaiReepBok (when waterrises, we tell) are Facebook account that updated news regarding flood. Theirlast activities were October and September 2012.
Category III Communication that was created for flood purpose and havefunctioned up till now.
 www.thaiflood.com and its Facebook and Twitter account were lunchedduring flood in 2010 and now continues to broadcast flood-related
information. Now it has over 70,000 likes.
 Volunteers watchdog for Bangkok flood (in Thai) is Facebook account thatcreated during the flood and still posts flood information.
Though social media has proven to be a popular and effective tool forsharing information, it can hinder response efforts especially when theinformation is incorrect, malicious, outdated, and inaccurate. In some cases, thelocation of the hazard or threat was inaccurately reported, or some requests forhelp were retransmitted repeatedly even after victims were rescued.
5. RECOMMENDATIONS FOR DISASTER INFORMATIONDISSEMINATION IN THAILAND
The 2011 flood has led to the necessity that the government established acomprehensive framework for better management of flood disaster in the future.
As a result, on 13 February 2012, the government issued the Regulations of the
Office of the Prime Minister to improve flood and water prevention andmitigation by integrating work plans of relevant agencies and establishing acentral unit that gives command on water management. This directed to theestablishment of the Office of the National Water and Flood Management Policy(NWFMP), run by the National Water and Flood Management Policy Committee,
chaired by the Prime Minister, with the hope to make comprehensive national
water and flood management policy.
However, information communication and dissemination is one of theessential aspect determining whether or not Thailand is to achieve water and flood
management. Some hindrances can pose threat to the credibility, and the
basic
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disaster information
dissemination: Case
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Vietnamgovernment might not be able to achieve what it has hoped for. To avoid
repeating the 2011 flood’s history, strategies for effective disaster information
dissemination are proposed in a 3-tiered framework; 1) decision making andwarning issuance, 2) information dissemination, and 3) disaster preparation andrisk reduction.
Tier I Decision making and warning issuance So far, there have been at least 2 government agencies whose duties are todisseminate flood-related information in times of crisis; for example, NDWC
and FROC. As a result, there is possibility that Thai people will be confusedover which agency they should listen to. Choosing only one agency isrecommended to create a true single command to avoid redundancy andconfusion.
 This single command must be focal for disaster-related matters. It must be theplace where information from monitoring agencies is concentrated andprocessed, decision is made, and warning is issued.
 It is recommended that NDWC takes the leading role in disaster information
dissemination as its objective was aimed to respond to any disaster that mightoccur in Thailand, unlike any other agencies in Thailand. Also, since its
establishment in 2005, NDWC has gradually matured and developed a strong
institution needed for disaster information dissemination especially in termsof relationship with other agencies, existing disaster-related technology, andties with the people.
Tier II Information dissemination
 It is encouraged that the government should use as many and various
channels as possible to deliver message to the people since the people are nothomogenous and can be categorized in various groups like the handicapped,
the flood-inexperienced, foreigners, and the elderly.
 The use of high-technology devices as a means to deliver information must be
encouraged such as issuing warning through mobile phones, and sending
useful information through websites and social network.
 However, an on-site information dissemination cannot be left out as it is very
crucial to deliver information to the people who have no access to hightechnology devices. It also help complete a 2-way communication as an onsite information officer can bring some input voiced by the people back to thecommand center, so that the government can supply accurate solutions.
 Since FROC’s messages were reported that they were irrelevant informationthat people did not really need. The content of messages during flood disasteris recommended to focus on reporting current situation, issuing warning whenneeded, informing of an evacuation, and providing information regarding risk
reduction and activities that help reduce risk.
Tier III Disaster preparation and risk reduction
 The government should also focus on the preparation. Disaster education andpreparation should be continuous even though there is no coming disaster.
 Behavioral changes are more likely if they are self-motivated, rather than
imposed, and it is likely that some people will have to hear the message
coming at them from multiple directions before it has any impact. Therefore,

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developing an awareness of current flood information sources such as
websites, brochures, and flood campaigns offers potential for empowering
individuals and communities to mitigate flood risk in an appropriate manner.
Scope of content can be larger than that needed in times of disaster andstakeholders can be anyone in the society, from government agencies toparents, sidewalk posters to school teachers.
Means of promoting information sources includes dissemination throughmass media and circulation by post or through recognized access points suchas train station, council officers, bus stops, universities, and libraries.

ACKNOWLEDGEMENT
This study was done as a part of the research project “Design of Disaster
Information Dissemination system and Proposal of Technical Strategies for
Supporting Asian Rural Communities” supported with Grants in Aid for Scientific
Research by Japan Society for the Promotion of Science.
REFERENCES
Bangkok Biz, 2011. Thai Social Network Behaviour during Flood Crisis (in Thai).
October 26, 2011. Retrieve July 2013, from www.bangkokbiznews.com
Bangkok Post, 2013. Government shows its intractability. May 20, 2013.
Retrieved July 2013, from http://www.bangkokpost.com/opinion/opinion/350880/
government-shows-its-intractability.
Bradford, R.A., and O’Sullivan, J.J., 2011. Improving Communication Strategies
for Effective Flood Risk Management. Unpublished paper for National Hydrology
Conference. Retrieved July 2013, from http://www.opw.ie/hydrology/data/speeches/05%20-%20Bradford%20-%20Improving%20 Communication%20
strategies%20for%20effective%20flood%20risk%20management.pdf
Chingchit S, 2011. Thailand Flood: Not Enough to Destroy the Government. In
IPRIS Viewpoint, Volume 78, December 2011.
Coben R., 2011. UN: Southeast Asian Floods Trigger Humanitarian Crisis.
October 17, 2011. Retrieved July 2013, from http://www.voanews.com/content/
thai-soldiers-rush-to-reinforce-bangkok-flood-walls-132036703/ 146797.html
Cole T.W., and Fellow K.L., 2008. Risk Communication Failure: A Case Study of
New Orleans and Hurricane Katrina. In Southern Communication Journal,
Volume 73, Issue 3, Page 211-228. Routledge, London.
Larnard J., and Sandman P. M., 2011. Over-Reassuring Thai Crisis
Communication about the Great Flood: When “Restoring Trust” is too Much to
Expect. Retrieved July 2013, from http://www.psandman.com/col/Thai-flood.htm
Matichon, 2011. ABAC Poll Revealed Majority Distrusted FROC and Evaluated
3.36 from 10. October 18, 2011. Retrieve July 2013, fromhttp://www.matichon.co.th/news_detail.php?newsid=1318911293&grpid=03&catid=03
Reuters, 2011. Thai Govt Faces Lawsuit over Flood Crisis Handling. December
22, 2011. Retrieved July 2013, from http://www.trust.org/item/?map=thai-govtfaces-lawsuit-over-flood-crisis-handling/
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dissemination: Case
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dissemination:
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VietnamThairath, 2011. People unsatisfied: FROC SMS were useless (in Thai). October24, 2011. Retrieve July 2013, from http://www.thairath.co.th/content/tech/211564
Tinker L.T., and Galloway E.G., 2009. “How to communicate flood risks
effectively” in Journal of Business Continuity & Emergency Planning. Volume 3.
Number 3.
World Bank, 2011. The World Bank Supports Thailand’s Post-Floods Recovery
Effort. December 13, 2011. Retrieved July 2013, from http://www.worldbank.org/en/news/feature/2011/12/13/world-bank-supports-thailands-post-floods-recoveryeffort

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Analysis of initial disaster responses
for disaster management stakeholders
in emergency and recovery phasefor sustainable disaster management system
Muneyoshi NUMADA1 and Kimiro MEGURO2
1
Research Associate, ICUS, IIS, The University of Tokyo, Japannuma@iis.u-tokyo.ac.jp
2
Professor, ICUS, IIS, The University of Tokyo, Japan
ABSTRACTThis research aims to develop a “Sustainable disaster/emergency management
system” that enables “seamless transfer from ordinary times to emergency
situations”.
The system is a time-series disaster management system for that the disastermanagement stakeholders will no longer be confused by unexpected conditions. In
ordinary times, vulnerable or weak points and problems are analyzed and solved.
Just before a disaster occurs, emergency alert will be run. In after disaster phase,damages are accurately assessed and are responded accordingly.
To develop this system, it is necessary to make a "spatio-temporal disastertransition model". Because no such model exists today, many disastermanagement stakeholders have no idea what they should actually do or how theiractivities contribute to disaster reduction. When they all become aware of themeaning of their roles, effective disaster management cycle would be put into
practice.
The key factor in developing effective spatio-temporal disaster transition model is
to make accurate estimation ahead of time even from limited information, andthen making the best response.
Needless to say, no matter how well we grasp the spatio-temporal transition, it isnecessary that each stakeholder has the correct understanding of his/her
assignment, or else appropriate disaster response will never be possible.
This paper focus on making and defining disaster response flows for each disastermanagement stakeholders by analyzing the responses during the Pacific coast of
Tohoku earthquake on March 11, 2011. Yabuki town located in Fukushima
prefecture is used for the case study of this analysis. The results show that theanalyzed flow can clearly explain the role of each stakeholder to response in theemergency and recovery phase.
Keywords: initial disaster response, disaster management stakeholders,sustainable disaster management system551

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1. INTRODUCTION
At 14:46 JST (5:46 UTC) on March 11th, 2011, an earthquake of a moment
magnitude 9.0, the largest earthquake ever recorded in Japan, struck off the shoreof the Sanriku area in the Tohoku Region. The “mega tsunami” followed, deeply
hitting indented coastal areas and bringing enormous and devastating damage tomany cities and villages in the area. Damage by the “mega tsunami” was not only
limited to buildings, but the resulting fires destroyed many communities, taking
lives of thousands. Moreover, nuclear power plant (NPP) facilities sufferedcomplicated and serious damage. This earthquake was later officially named “The2011 off the Pacific coast of Tohoku Earthquake” by the Japan Meteorological
Agency (JMA).
The Magnitude 9.0 “off the Pacific coast of Tohoku earthquake” on March 11,
2011, has caused extensive damage that still continues today. Although Japan had
been recognized as one of the leading countries in disaster management, its poorlevel of risk management or numerous problems in disaster reduction wererevealed by this unexpected and unprecedented disaster.
Throughout the centuries, Japan has suffered from natural disasters of manydifferent kinds. And now that the country has entered a seismically active period,
damage mitigation is addressed as the major national issue. The Great East Japan
Earthquake has taught us the priceless value of safety and sustaining the quality oflife.
As one of the solutions to minimize damage, we suggest a total disaster response
cycle featuring measures on the following: pre-disaster damage prevention,
damage reduction, disaster prediction, alert system, damage assessment,
emergency response according to damage assessment, and smooth
recovery/reconstruction. Current efforts by regions and organizations should be
reviewed (in terms of hard/software and disaster response) while different kindsof hazard and its levels (in terms of intensity, extension and frequency) should
also be taken into consideration. After a careful checkup, weak points are sorted
out, prioritized under limitations of time and budget, and then starting from theweakest agenda, things move ahead for improvement. This process is the mosteffective and efficient way to change "the way things are today" into "what theyneed to be in the future".
Our research aims to develop a “sustainable disaster/emergency management
system” to accomplish the above-mentioned process. By following this system,
problems will be sorted out accurately, improvements made at ordinary times,
alert will be heightened before urgent danger, damage precisely assessed after
disaster, and damage response conducted appropriately according to theassessments. It realizes “seamless transfer from ordinary times to emergency
situations”.
The biggest challenge lying ahead is to develop a "model which accurately
estimates spatio-temporal disaster transition". Because no such model exists
today, many disaster management stakeholders have no idea what they should
actually do or how their activities contribute to disaster reduction. When they all
become aware of the meaning of their roles, effective disaster management cycle

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would be put into practice. The key factor in developing effective the spatiotemporal disaster transition model is to make accurate estimation ahead of timeeven from limited information, and then making the best response. Needless tosay, no matter how well we grasp the spatio-temporal transition, it is essential thateach stakeholder has the correct understanding of his/her assignment, or else
appropriate disaster response will never be possible.
Effective initial responses in crisis management are important to reduce or
minimize the impact of large-scale disasters such as the Great East Japan
Earthquake for the prevention of secondary disasters and rescue.
However, it is difficult to operate initial disaster responses effectively for thedisaster response headquarters just after the disasters under the condition of thelimitation of human and product resources.
In order to solve these problems, there are the current researches such as
standardization and system of disaster responses1,2).
This study analyze the patterning the kinds of disaster response, defining its flow
and evaluating its amount of volume which are expected in advance to build
effective the spatio-temporal disaster responses model. By understand these
operations for each different actors or players, it will be possible to carry out
disaster responses immediately under the condition of confused disaster phase.
This paper provides the case study that the initial responses of Yabuki town inFukushima prefecture are analyzed during the 5days after the Tohoku earthquake
to achieve the effective disaster system.
2. Analysis data
The analysis data in this paper is obtained from the staffs who worked for thedisaster response immediately after the earthquake from 11th to 15th March for 5
days.
Table 1 shows the analysis data for a staff which are divided into six time sections
for one day as the early morning, morning, daytime, afternoon, evening, night.
The around half numbers of staffs answered to that with the exception of the staffs
who could not engage in disaster responses at the time and who have already leftor retired after the earthquake (Figure 1). If the staffs transferred to the new
department from the department at the disaster, we collected the data as that staffs
belongs to previous department.
3. Analysis of disaster responses
3.1Time historical analysis
Table 2 shows the change of the time history of disaster emergency responses.
The number inside of this table is the total number of working staffs during thetime division. The vertical line is ordered from the higher total numbers ofworking staffs for a response category item.
According to this result, "food supply", "water supply", "damage investigation"and "evacuation management" are frequent in the order during the five days. 33
Analysisof initialdisasterforresponses
for disaster management
in emergency
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disaster management
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in emergency
andrecoveryphaseforsustainabledisastermanagement
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October
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Hanoi,Hanoi,
Vietnam0ctober
Vietnamstaffs worked for the damage investigation on March 11. Many staffs worked forthe food supply from March 11.
The number of staffs gradually increased for the water supply and the most of thestaffs worked for that on March 14. Because the water in the water tank on theroof of the government building was used up immediately after the disaster, it wasnecessary to supply water to the people. The water supply was carried out by thetruck with water tank at the entrance of the government building.
For evacuation centers, in addition to the distribution of goods, the staffs walked
around the all evacuation places to check the number of evacuee.
Due to the damage of JR (Japan railways), some passengers could not move on
March 12. Yabuki town received the people who could not go home, and Yabuki
town transferred the people to the Shinshirakwa station by the bus of town on thenext day of the earthquake
Table 1: example for the analysis data (shown from 11th to 12th March)
2013/3/11
Immediate
Eveningly
Division/ Namedamagesurvey2013/3/12

NightdamagesurveydamagesurveyMidnight

Early
morningmorning

DaytimedamagesurveyFood supply

Water
supplydamagesurveyafternoon Evening
Water
supplyWater
supplyNight
Food supply

Staffs (People)
15

13

12

11

9
6

5

6

7
4

3

5

5

6
4
1

2

0

Figure 1: The number of respondents according to divisions
3.2 Analysis for each division
We analyzed the disaster responses for the each department of the town. Table 3
shows that all numbers of working staffs for the each department during 5 days
totally. The number in the table describes the working load in each departmentthat the total working people times the total working hours (people × working
hours) assumed as 3 hours for each time sections.

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Table 2: Time history of disaster response (unit: number of people)
2013/3/12

2013/3/13

2013/3/14

2013/3/15

Immediately
EveningNight
Midnight
Early morning
morning
Daytimeafternoon
Evening
Night
Early morning
morning
Daytimeafternoon
Evening
Night
Early morning
morning
Daytimeafternoon
Evening
Night
Early morning
morning
Daytimeafternoon
EveningNight

2013/3/11

Response items

Food supply
Water supply
Damage investigation
Evacuation
Information collecting
Goods supply

6 8 8 13 6 9 8 9 9 12 1 14 1 12 8 13 1 16 12 14 11 7 11 13 13 13 9
1 1
3 6 3 7 12 3 6 12 9 16 11 7 9 2 17 18 16 14 8 16 14 14 11 7
33 13 8 6 4 16 17 11 7 5 2 6 6 3 4 5 2 4 9 9 5 7 5 8 4 7 5 3
1 7 11 5 4 6 3 5 4 8 4 11 9 9 4 2 5 7 4 5 5 5 5 6 5 6 6 9
4 1 8 7 5 2 4 5 3 4 4 2 1 2 2 3 5 4 3 2 2 4 4 2 5 4 4 4
2 2
2 2 4 3 2
2 3 3 1
1 3 4 4 3 3 2 3 5 6 5 1
Emergency safety check of house
1 1
2 3 3 3 3 1 2 3 3 3 3 2
2 2 2 2 2 2 3 3 3 3 1
Meeting
1 1 2 3 2
5 1 4 2 2 1 8 1 3 1
1 7 1 2 4 1 1 2 1
Staying at home
6 1 5 4 3 2 4 4 2 4 4 4 5 4 1
1 1
2
Restoration
2
1 1 3 3 2 1 2 2 2 3 2 1 1 2 1 2 2 2 1 4 4 4 4 3Others
5 2 3 2 3 3 2 1 2 4 4 1 1 2 1 2 4 1
1
2 1
1
2
Safety check
1 2 2
6 5 7 6 3 1 3 2 3 1 1
1
1
1
1
Office counter work2
1 2 1 11 3 2 3 3 3 2 3 3 3 2
Traffic control
2 5 4 1 1 1 1 1 1 1 1 1 1 1 1
2 1 1 1 1
1 1 1 1 1
Disaster wireless system
1 1 1
2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Clearing up
1
1 2 2 4 3
4 2 2
1
1 1 1
1
A child's delivery
6 8 2Fire-fighting round
1 1
1 1 1 1 1 1 1 1 1 1 1 1
Disaster waste
1 1 1 1 1 1 1
1 1 1
1 1 1
Suffering certificate
1 1 1
1 1 1
1 1 1
Temporary house
1 1
1
1
1 1 1
Liaison and adjustment
1 1
2
1 1 1
Acceptance wide-area support
2 2 1
1
Evacuation guidance
4 1 1Parliamentary correspondence 1 1
12
Support disabled persons
1
1
1
1
1
Volunteer1
1 1 1
Supply of food for school children
1 1
11Information arrangement
1 1 1 1
Installation of a temporary lavatory
1
1
1
Check a school road
1 1
1Victim unable to return home
1 1
Defense
1
1

Sum

284
261
214
161
109
66
58
57
57
55
50
47
35
34
28
26
16
14
13
9
7
7
6
6
5
5
4
4
4
3
3
2
2

Division

Project management
General Affairs
Tax
Residential life
Health and Welfare
Industrial development
Urban construction
School education
Lifelong learning
Kindergarten

Food supply
Water supply
Damage investigation
Evacuation
Information collecting
Goods supply
Emergency safety check of house
Meeting
Restoration
Safety check
Office counter work
Traffic control
Disaster wireless system
A child's delivery
Fire-fighting round
Disaster waste
Suffering certificate
Temporary house
Liaison and adjustment
Acceptance wide-area support
Evacuation guidanceParliamentary correspondence
Support disabled persons
VolunteerSupply of food for school children
Information arrangement
Installation of a temporary lavatory
Check a school road
Victim unable to return home
DefenseTable 3: disaster response and division (unit: people times hours)Sum

138 90 15 27

9

15

0

33

0

0

0

0

0

0

0

0

0

0

0

9

0

0

0

0

0

12

0

0

0

3

351

3

96 30 42

6

90

0

0

93

0

0

6

0

0

0

0

0

0

0

0

0

0

0

3

0

0

0

0

6

0

375

75 186 24 99

9

33

0

0

3

0

0

3

0

0

42

0

0

0

0

0

3

0

0

0

0

0

0

0

0

0

477

81

6

3

0

36

0

0

0

30

3

84

0

0

39 27

0

6

0

0

0

0

0

0

0

0

0

0

0

321

3 129 6

21

0

3

0

6

48

0

0

0

0

0

0

0

15

0

3

0

15

9

0

0

0

0

0

0

342

21 123 84 24 24

0

0

0

0

0

0

18

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3

297

0

0 138 0

18

6

0

72

0

0

0

0

0

21

0

0

0

0

0

0

0

0

0

0

0

0

438

0 120 18 15

0

0

0

15

0

0

0

0

0

0

0

3

0

0

12

0

0

9

0

0

789

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

291

36 84 390

9

3 114 3

0

0

33

0

0

0

0

0

9

12

0

0

0

0

0

9

0

0

0

669

39 45

6

0

0 183 00

99 36 222 90 150 0
42 111 66 36 36
234 7590Parliamentary office work

0

15

0

0

0

0

0

6

30

0

0

0

0

0

0

0

0

0

0

0

0

12

0

0

0

0

0

0

0

0

63

Teller's cage

120 0

0

0

0

0

0

0

0

0

24

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

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For the project management division, "food supply (138 [people × time])" is thehighest, "water supply (90 [human × time])" followed by it. As the managementof "Conference" is the one of the role of the disaster response headquarters, thiswas controlled by the project management division. The "meeting" by the school
education division means that they discussed about how to response to thestudents and restart the classes.
The project management division takes a role of the wide-area supports from themunicipalities located in outside of damaged area (9 [human × time]) as well.
Yabuki town were received the supports from Mitaka city, Towada city,
Kawaminami city and the others.
The General Affairs Division mainly worked for "water supply", "goods supply","Recovery". In addition, the operation of evacuation centers and theunderstanding of the number of the evacuees are managed.
The Tax Division mainly worked for water supply, operation of evacuation
centers and food supply. The evacuation guidance shows that the division induced
the people who came to the governmental building just after the earthquake.
The residential life division mainly worked for the community wireless system,
food supply, building inspection survey, disposal of wastes, issuances of a victim's
certificate.
With regard to the community wireless system, three kinds of those systems thoseof Yabuki town, volunteer fire group and Fukushima prefecture were used.
On March 11, information was provided to the people in every one hour, and thenon March 12 the frequency of information was provided in every two hours.
Immediately after the disaster, information about severed road was send to thegovernment from a volunteer fire group, and then the staff in the room of thecommunity wireless system sends its information to the urban construction
division. The room of the community wireless system played the role of theinformation hub in the town.
The Health and Welfare Division worked for care of evacuees and provide food in
evacuation centers.
The Industrial Promotion Division conducted a damage survey and water supply
mainly. For damage investigation, they checked the function of agricultural
related facilities.
The Urban construction division conducted a damaged survey of infrastructures,
recovery of infrastructures.
The School Education Division conducted a damage survey of school facilities,
food supply, and operation of evacuation center.
4. Comparing the responses in the Great East Japan Earthquake and theregional disaster prevention plan
By comparing the responses in the Great East Japan Earthquake and the regional
disaster prevention plan, we analyze the important view for rebuilding theregional disaster prevention plan.
Figure 2 shows the relationship between disaster responses in the Great East Japan
Earthquake and the second chapter of emergency response of Yabuki town
regional disaster prevention plan.

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Table 4 shows the responses for classification of each division. In order tounderstand the working load for each division, we estimate those values by
calculating the denominator that the total working hours each tissue wasdetermined by dividing each task.
According to the Figure 2, "Gathering and transmission of Information in Section
3" was spent the most frequently. This is due to the damaged survey and safety
confirmation by the School Education Division and the urban construction
division (Table 4).
Food supply in Section 12", water supply in Section 13, operation of evacuation
center in Section 6 and goods supply for daily necessities in Section 14.
Here we want focus on the responses those were not carried out in the earthquake
such as "Section 7 rescue measures," "Section 8 emergency measures", "Section
15 Medical Measures", and "search dead bodies in Section 18 ", and some actions.
This is because that the human damage was very slightly, those actions were notrequired such as emergency response or rescue in Yabuki town.
Figure 2: Comparing the responses in the Great East Japan Earthquake and theregional disaster prevention plan
Work load ( People × hours)








Setting disaster countermeasures office
Asignment of staffs
Information collecting and communication
Management of information system
Measures to prevent floods
Evacuation
RescueEmergency responses
Removal of an obstacle
Transportation
Disaster defense
Food supply
Water supply
Goods supply
Medical measure
Sanitation
Environmental measures
Dead body
SchoolHousing measure
Public facilities
Electric power public telecommunication
Volunteer cooperation
Disaster Relief Law
disaster restoration plane for public…
disaster restoration for damaged people
fire prevention plan
Support disabled persons
others (parliamentary)

Analysisof initialdisasterforresponses
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Teller's cage

Parliamentary office work

Kindergarten

Lifelong learning

School education

Urban construction

0
0
0
0
36 33
0
0
0
0
48 102
0
0
0
0
0
0
6
3
0
0
3
75
96 186
90 33
0
0
0
0
0
0
0
0
0
0
21
0
0
0
0
0
3
0
0
0
72
3
0
0
0
42
0
0
0
0

Industrial development

33
9
36
0
0
27
0
0
0
0
3
138
90
15
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

Health and Welfare

Setting disaster countermeasures office
Asignment of staffs
Information collecting and communication
Management of information system
Measures to prevent floods
Evacuation
RescueEmergency responses
Removal of an obstacle
Transportation
Disaster defense
Food supply
Water supply
Goods supply
Medical measure
Sanitation
Environmental measures
Dead body
SchoolHousing measure
Public facilities
Electric power public telecommunication
Volunteer cooperation
Disaster Relief Law
disaster restoration plane for public facilities
disaster restoration for damaged people
fire prevention plan
Support disabled persons
others (parliamentary)

TaxSec. 1
Sec. 2
Sec. 3
Sec. 4
Sec. 5
Sec. 6
Sec. 7
Sec. 8
Sec. 9Sec. 10
Sec. 11
Sec. 12
Sec. 13
Sec. 14
Sec. 15
Sec. 16
Sec. 17
Sec. 18
Sec. 19
Sec. 20
Sec. 21Sec. 22
Sec. 23
Sec. 24
Other
Other
Other
Other
Other

Residential life

disaster responses/ Division

General Affairs

SectionProject management

Table 4: Comparing the responses in the Great East Japan Earthquake and theregional disaster prevention plan in each division

Sum

0
3
0
0 120 0
9
6
0 171
0
0
0
0
0
0
9
0
0
18
51 30 108 327 387 102 207 0
0 1317
84
0
0
0
0
0
0
0
0
84
0
0
0
0
0
0
0
0
0
0
0 132 24
0
90 36 48
0
0 507
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3
0
18 72
0
0
0
0
0 102
0
0
3
0
0
0
0
0
0
6
81 39 21
0 111 42 234 0 120 864
6
45 123 0
36 111 75 15
0 783
0
21
0
0
0
0
39
0
0 198
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
39
0
0
0
0
0
9
0
0
48
0
0
0
0
0
0
0
0
0
0
0
0
0
21 24
0
33
0
0
78
0
0
0
0
0
0
0
0
0
21
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
9
0
0
0
0
0
0
0
12
0
0
0
0
0
0
0
0
0
0
0
0
0
18 18
0
3
30
0 144
57 48
0
0
0
0
3
0
24 132
0
0
0
0
0
0
0
0
0
42
0
15
0
0
0
0
0
0
0
15
0
0
0
0
3
0
0 12
0 15

Thus, empirical knowledge on disaster medical responses were not accumulated
based on experiences. However, as there are many medical facilities in Yabuki
town, the cooperation with medical institutions is very important to take aneffective disaster response in an aging society. The important things is to analyze
what kinds of disaster responses experienced or not experienced, with following
this results, it is necessary to build the regional disaster prevention plans
We found that many officials worked for the responses (food supply, water supply,and etc.) most of those are available not only government people.
The staffs belong to the management division such as the project management
division or The Tax Division and etc. worked for those responses which everyone
can do.
In order to perform disaster responses effectively with around 130 Yabuki town
officials, all disaster responses need to be classified according to the level orcharacteristics of the responses.
Then, we can apply the responses in accordance with the characteristics.
In this paper, the disaster responses are divided into four types.
(1) the responses by everyone can work immediately after disaster such as such as
management of the Volunteer Center etc., (2) the responses by government staff at
first stage of disaster but gradually shifting to the other people such as food supply,
water supply etc. (3) the responses by every government staff such as residents

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support, issuance of certificate, etc., (4) the responses by government staff with a
special skills such as restoration of infrastructure and lifelines, health issues etc.
It is important to make a category for each disaster response according to thesekinds of types in a regional disaster prevention plan. Then we can understandwhat kinds of disaster responses are necessary by staffs with special skills or
without those, and manage the limited resources effectively.
5. CONCLUSIONS
Our research aims to develop a “sustainable disaster/emergency management
system” to accomplish the above-mentioned process. By following this system,
problems will be sorted out accurately, improvements made at ordinary times,
alert will be heightened before urgent danger, damage precisely assessed after
disaster, and damage response conducted appropriately according to theassessments. It realizes “seamless transfer from ordinary times to emergency
situations”.
This study analyze the patterning the kinds of disaster response, defining its flow
and evaluating its amount of volume which are expected in advance to build
effective the spatio-temporal disaster responses model. By understand these
operations for each different actors or players, it will be possible to carry out
disaster responses immediately under the condition of confused disaster phase.
This paper provides the case study that the initial responses of Yabuki town inFukushima prefecture are analyzed during the 5days after the Tohoku earthquake
to achieve the effective disaster system.
AKCNOWLEDGEMENT
To write this paper, many staffs in Yabuki town support us. I describe here andappreciate deeply.
REFERENCE
1) IWASA Yuichi, HAYASHI Haruo and KONDO Tamiyo: Business Activity
Analysis of the "Basic Plan for Disaster Prevention" for More Standardized
Emergency Response, Institute of Social Safety Science (5), pp.193-202, 2003.
(in Japanese)2) Muneyoshi Numada, Shinya Kondo, Masashi Inoue, and Kimiro Meguro:
Analysis of Description of Local Disaster Management Plan for Smoothand Effective Wide-Area Support System During Large-Scale Disaster,JDR (Journal of Disaster Research), Vol.7 No.2, pp. 147-159, 2012.

Analysisof initialdisasterforresponses
for disaster management
in emergency
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disaster management
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in emergency
andrecoveryphaseforsustainabledisastermanagement
systemand recovery phase for sustainable disaster management system

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560

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Planning tool for urban sustainable
development management in Vietnam cities
NGUYEN THI THANH MAI
PhD. Head of Urban Infrastructure Planning (UIP), National University of Civil
Engineering (NUCE), Ha noi
Maixaydung@yahoo.com
ABSTRACT:
Viet nam is one of the Asian countries where there has been a fast economic
growth in recent years. Many challenges have emerged in urbanization process,such as the rapid increase of urban population and the continuing expansion ofurban periphery. As result, agricultural land and open space have gradually been
declined and replaced by buildings, roads with high density and increasingly
numerous motobikes and autos. This causes the excessive consuming the naturalenergy and destruction of human living environment. The more seriousness is thedeepened social cleavage and the urban poverty. It is clear that the traditional
urban management tools is becoming out of date and not overtaking the growthdemands of cities nowadays. So the question is that which is a effective
management tool for local government to deal with the problems and challenges
in urbanization, as well as to attain the objectives of sustainable development. In
this article, the author focus on studying on planning methods utilized in urban
development management. The assess and comparision between the traditional
planning tool and new planning methods like CDS will indicate that we shouldchange our mind on applying the new initiative in urban development
management for the era of deep integration in global economy.
Keywords: Urban management, Urban planning, Sustainable development.
1. INTRODUCTION:
Like other cities in Asia, Vietnam cities have been in the process of rapid
urbanization 1 under the context of globalization. The speed and scale ofurbanization have profoundly impacted urban areas, especially in the biggest
cities ( Ha noi, Ho chi minh, Danang). The challenges that those cities face with isincreasing population along with spatial extension on the urban periphery where
local management capacity is still weak and lack of development control
regulations. The impacts of urbanization process hence are narrowing the
agricultural land and open space, declining the natural resources (river, lake,
1

According to a MOC report in June 2013, Viet nam has 765 cities in which there are 2 largest
cities at special rank ( Ha noi and Ho chi minh), 13 cities at the first rank, 10 cities at the second
rank, 53 cities at the third rank, 60 towns at the fourth rank and 627 towns at the fifth rank .
Urbanization scale is 33%.

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Vietnamforest ecology, ...), pollutting air and bringing about accidents by using excessive
private vehicles (cars, motorcycles), degrading the infrastructure and service
system, creating an unbalance between economic growth and poverty that finallyexacerbating social issues.
The international organizations suppose that the best choice for all fast-growing
cities to deal with the challenges is implementing the targets of urban sustainable
development. The World Bank refers to 5 criteria for urban sustainable
development include economic growth bases on enhancing urban
competitiveness; making good living conditions to gether with decreasing urban
poverty, ensuring financial healthy and taking municipal governance relies on thestrength of the social community.
However the question for leaders of Vietnam cities is which effective
management tools could solve the problems and challenge in order to attain thetargets of urban sustainable development. Meanwhile, it seems that the traditional
planning methods for development management have not yet kept pace with therapid changes of socio-economic growth in the cities.
Some international organizations have actively contributed their initiatives to findout the innovative management tools that could assist the municipalities to solve
the urban challenge regarding land use management, infrastructure development,
environment protection and community economic development. In particular, theCity Development Strategy (CDS) tool proposed by the Cities alliance and its
member organizations, including the World Bank, is considered as a new
approach for municipality to overcome the disadvantages of traditional planning
tool (Son [1]). CDS aims at integrative and multi-sectoral planning process by
forsting the community participation with all their potential and enthusiasm.
The article below provides a review on traditional planning method being used in
Vietnam today, after that compares with the CDS approach to conclude of theessential changes in applying the innovative planning tool on city development
management aiming at sustainable socio-economic growth in the context ofinternational integration.
2. TRADITIONAL PLANNING METHOD IN VIETNAM.
The current planning process in Viet nam is generally inherited from the priorreforms in the subsidized economy and has not changed much so far. Traditional
planning method was profoundly affected by previously centralized planned
economy and has been adjusted in order to agree with the demands of socialistoriented market economy since 1986 (Quang, 2007).
2.1 Planning process: (diagram 1)
As regulation in Viet Nam, general development strategies were approved will befoundation to build socio-economic planning and sectoral plannings ( such astransport, agriculture) which are concretized by middle term and short term
development plans including groups of investment projects (Đạt, 2009)

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General socio-economic
development strategies,
sectoral development
strategies.

Socio-economicplanning and sectoralplanning

Socio-economic plans
and sectoral plans ofinvestment projects

Deploying the selected
investment projects

Diagram 1: General process on planning and implementing plans of investment projects in Viet nam
This process is implemented for most of socio-economic sectors as well as appliedon the different territories that belong to administrative hierarchies from central tolocal levels (province, city, district). There is mutual relationship among thespecialistic sectors and administrative levels in development management process(Achieve, 2009). In the sphere of city, the implementing process is a part of wholeplanning process and also comply with general principles.
Regarding the planning period, there are 3 types of basic planning: socioeconomic development planning, sectoral development planning and (spatial)
construction planning (diagram 2).
Socio-economic development planning leads the sectoral development plannings
to implement comply with general missions in the direction of hamonized andbalanced development among setors. While sectoral plannings stem fromrequirements of themselves will contribute their recommendations on completingthe content of general socio-economic development planning (Viêm, 2009).
Approved plannings will be basis for proposing the socio-economic development
plan and sectoral including a list of priority of investment projects. Likes this,those planning/plans will be implement at different territories belong toadministrative hierarchies. The planning/plan at higher level will regulate the theplanning/plan at lower level.
Construction planning is mentionned as creating physical environment where allsocio-economic sectors can operate.

Construction planning
Minstry or Department ofConstruction

Planning/Plan of socio-economic
development (Minstry or Department ofPlanning and Investment)

Planning/Plan of sectoraldevelopment (Minstry or
Department of related sector)

Nationally urban system
planning, regional planning andmetropolitan planning

Planning/Plan of socio-economic
development at national/ regional/
provincial level

Planning/Plan of sectoraldevelopment at national/ regional/
provincial level

Master planning

Planning/Plan of socio-economic
development at municipal level

Planning/Plan of sectoraldevelopment at municipal level

Zonning /Detail planning

Planning/Plan of socio-economic
development at district level

Planning/Plan of sectoraldevelopment at district level

Direct relationship
Co-ordinative relationship
Basis to propose investment projects
Diagram 2: Relationship among 3 types of basic planning, including socio-economic
development planning, sectoral development planning and (spatial) construction planning
Planning tool for urban sustainable development management in Vietnam Cities
Planning tool for urban sustainable development management in Vietnam cities

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2.2 Master planning tool:
In Viet nam, construction planning ( spatial planning) considered as an output ofdevelopment planning process. It is impacted by 2 planning components, socioeconomic planning and sectoral planning. The product of construction planning
represented by the land use planning drawings These drawings will be basis toselect a land for investment projects as well as to manage deploying the projects
in practice. Besides this, there are more sectoral plannings be proposed by otherministries/departments, for example the transport development planning proposedby Ministry of Transportation, agricultural land use planning set up by Ministry ofagriculture and rural development… It is obviously by this method there is issuesof overlapping and unfitness among the sectoral plannings, even when there ispresence of experts from varioius departments/ ministries to consult and to give
opinions in construction planning.
Today the master planning tool is considered as old approach in making theconstruction planning. This method has a quite long history of thousands of years
and was popularly utilized in the 60s, 70s in the socialist countries where
centralized planned economy existed (Son, 2005). The master planning is
supposed that get high technically and inflexible by its products are colourful
drawings regulated through rigid standard system. The ideas of master planning is
mainly decided by specialists like planners and architects who have responsibility
to concretize the point of views of central government and municipal leaders byplanning solutions. The participation of social community, such as residents,
businesses and private economic sectors was recently regulated in the law of
construction, however, it seems quite fomalistic and low effective. Therefore, land
use planning formed by the traditional planning tool is considered as impracticaland unadaptable with self-motivated market economy (Son, 2005).

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2.3 Development plan on investment projects
National development strategies
Municipality (DPI)
Sending forecasts, objectives,budget and other mobilized
resources ... to districtauthority.
After that, getting draft plans
and recommendations from
district authority.

Construction planning(Department of construction)

Review and approval base on
sector planning of
departments (MONRE,
MARD…)

Step 1

Step 2District/ departments

Synthesising and adjusting thegeneral plan according to the draft
plans received from local authorities.
Guiding local authority to adjust
Finishing Official Plan, and submit toPeople's Committee.
Approved Official plan is foundation
to deploy the investment projects

Budget distribution to investment projects belong tosocio-economic sectors/departments and to districts

DPI

Deploying theinvestment projects
Independent non-state
investors.

Agree and license
apply for aninvestment license

Diagram 3: Process of proposing plans on investment projects in Vietnam
Development plan on investment projects is proposed on the territorial units
according to administrative management levels and in the socio-economic
industries (ministries/departments). The process of proposing plan is carried out
through 2 steps ( Sơn, 2007, Đạt, 2009) (diagram 3) :Step 1: Municipality (DPI) sends the forecasts, objectives, informs budget andmobilized resources... to the district authorities and departments. These units willbuild up draft plan of investment projects for themselves.
Step 2: Municipal agencies (DPI) synthesis and correct the general plan bases onrecommendations mentionned in the draft plans of the districtauthorities/departments.
After that municipal agencies guide the
districts/departments to adjust their plan. An official plan will be complete andsubmit to People’s committee in order to have approval. Ratified official plan
including a long list of priority of investment projects is basis to manage theconstruction activities in practice.
In theory, this process shows an unity amongs general plan of municipality andspecific plans of districts/departments relied on two-dimension information fromtop-down to bottom-up, and vice versa. However in reality, the investment
projects proposed by districts/departments just focus on particular benefits anddemands of themselves without multi-sectoral coordination. The approved official
plan does not represent for the benefits of all departments/sectors at once, as wellas has not created yet a coordinative action plans between stakeholders. There isPlanning toolPlanningfor urban
sustainable
managementmanagementin Vietnam cities
tool
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and to contribute their oppinions in the making process. As results, it has notmobilized yet various financial resources out of state budget, particularly in theinfrastructure development projects.
In the traditional planning method , the role of municipality as an exclusive
provider and market must comply with ( Alan coulhard, 2007).
3. CITY DEVELOPMENT STRATEGY (CDS):
3.1 CDS process:City Development Strategy CDS

Targets on urban sustainable
development
Com
perati
vness

Liva
ble
city

Finacialhealth
y

Good
gover
nance

Planning(ISP),
composed ofdevelopment
strategies andstructureplanning

Plans oninvestment
project groups(MSIP)

Implementationof selected
projects forannual plan

Participation of social partners, community, private investor( idea, financial resources, labor, initiatives…)

Diagram 4: General process of implementing CDS
CDS combines 2 phases (planning and proposing plan of investment projects) into
one complete process in which the preferential mechanism is set up to encourage
the community participation. There are 3 initiative tools applied in CDS
implementation process:- Integrated Strategic Planning (ISP)- Multi-Sectoral Investment Plan (MSIP)- Community participation (CP)
3.2 Integrated Strategic Planning (ISP):
Integrated Strategic Planning (ISP) covers 3 planning components such as socioeconomic planning, spatial planning and environmental planning (land use
planning, environment) (diagram 4). ISP promotes cooperation among thestakeholders including the state, social community, organizations and the private
sector to mobilize resources and to coordinate in operation aims to planningtargets of urban sustainable development. Outputs of ISP include the development
strategies (Son, 2005) and structure planning which is an innovative planning canreplace the traditional master planning.

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Structure planning was formed in 1950 applied on new city planning in UK andpopularly utilized in the 1970s. Structure planning does not regulate specific typesof construction or rigid stadards on planning drawing. It prepares a long term
development plan for land use and proposes the orientation of spatial structuredevelopment for the city future. Structure planning approach is conformably
utilized to establish the city general planning. It permits easily adjusting at detailplanning because of its flexibility (Son, 2005)
3.3 Multi-Sectoral Investment Plan – (MSIP)
ISP development strategies are important basis to establish the MSIP. These
strategies will be translated into medium-term and long-term development plansincluding a long list of investment projects. MSIP process is deployed base on theprinciples of multi- sectoral coordination to propose priority of construction
projects. Beside this, a capital investment program CIP also be annually done withpreparation of the municipal budget each year for construction. (Dat, 2009)
3.4 Community Participation (CP)Community participation approach is paid attention in performing CDS. The
social community and stakeholders such as local government, businesses,
residents ... by their commitment efforts to involve in the CDS implementation
process, from the step of identifying existence, defining opportunities untill topropose a future vision and to find out the coordinative action plans aiming at a
multi-sectoral and comprehensive strategies.
In summary, CDS is the integrated, multi-sectoral planning tool that assists
effectively the authority to propose development strategies and investment plans.
Spatial planning is a part of whole process, not a final output as it is in traditional
planning process. Results of CDS represents an coodianative action program
between stakeholders. It assigns concretely who, when and how to participate in
implementation process. Hence CDS tool will bring a new way in urban
development management, the market orders and city as a provider (Alan
CoulHart, 2007).
4. CONCLUSIONS:
Thus, the CDS approach is as an initiative to assist the municipal authority toestablish the development plan by encouraging the enthusiastic participation ofcommunity and promoting the close coordination between social-economic
sectors. CDS is considered as effective tool to find out the actions aiming at theequitable growth and sustainable social development. It's time that themunicipalities needs to change their inherent mind on deploying the city
development planning by inserting the CDS approach into traditional methods.
Although the CDS has been studied by the international organizations in the casesof Ho Chi Minh, Ha Long, Hai Phong and Can Tho, it still considered as pilot tool.
It has not yet been executed in reality for experts to draw experiences.
However, CDS tool want to go into our life and effectively utilized in practice, itis necessary to adjust the current management mechanism in order to create

Planning toolPlanningfor urban
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professional departments.
REFERENCES
Tien, Nguyen Hong, 2013. Role of Ministries, Industries in drainage andsewerage management in Vietnam, Conference on Role of Stakeholders insewerage and Wastewater treatment Management, Ministry of Land,
Infrastructure Transport and Tourism, Japan and MOC, Vietnam.
World bank, 2012. Assessment on urbanization in Vietnam, publish by WB.
Son, Nguyen Dang, 2005. Toward swifting the planning method, Publish House ofConstruction
Dat, Nghiem Xuan, 2009. Multi-Sectoral Investment Plan. Trainning course on
capacity building for urban planners in VietNam, Modul 1, publish by Vietnam
institute of Architecture, Urban and Rural Planning.
CoulHart, A., 2007. Urban planning and management , Training course on
environment management, course material approved by World bank and MOC.
Quang, Nguyễn, 2007. Changes on Planning method in Viet Nam, Training course
on environment management, course material approved by World bank and MOC.
Hai, Ngô Trung, 2009. City Development Strategy in Hạ long city, Trainningcourse on capacity building for urban planners in VietNam, Modul 1, publish by
Vietnam institute of Architecture, Urban and Rural Planning.
Viem, Đo Duc, 2009. Socio-economic planning, sectoral planning andconstruction planning in Vietnam, Trainning course on capacity building for
urban planners in VietNam, Modul 1, publish by Vietnam institute of Architecture,
Urban and Rural Planning
Tuan, Hoang Ngoc, 2007. Some challenges in building CDS in Hai phong city,
Training course on environment management, course material approved byWorld bank and MOC.

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The integration approach for broad-scaleland-use change prediction modelling
Anh Nguyet DANG1 and Akiyuki KAWASAKI2
1
Research Assistant, Regional Network Office for Urban
Safety (RNUS) Asian Institute of Technology (AIT), Thailand.
dang@ait.ac.th2
Associate Professor, International Center for Urban Safety
Engineering (ICUS) Institute of Industrial Science (IIS), the University of Tokyo,
Japan.
ABSTRACTThe magnitude and pace of human intervention on land surface has markedly
increased and become unpredicted. Half of the Earth’s ice-free land surface has
been transformed by humankind and most of the rest has been managed forhuman purposes over the past 10 millennia or so. Land-use change models havebeen developed to analyze the causes and consequences and assess the impacts ofland-use change on ecosystems as well as supporting land-use planning andpolicy. At broad-scale, the complexity of land-use systems has called for a
multidisciplinary analysis. However, there is a challenge of abstracting theinteraction among a large number of multi-level factors to explain broad-scaleland-use change processes. No single model is able to do so. Recently, a newer
approach known as integrated models has been carried out with the promise ofovercoming the limitation of single model application. In this study, theconceptual framework was introduced to facilitate integration approach in broadscale land-use modeling. We do this by:(1) summarize the most importantconcepts and characteristics of broad- scale land-use models from previous
studies, (2) discuss about the framework for modelling land-use change at broadscale and (3) propose the application of this framework for land-use change for
DakLak province, Vietnam. This work could be used for better understanding of
the potential of integrated approach and provide scientific support for land-use
planning and managements at broad-scale.
Key words: land-use change model, broad-scale, integrated model
1. INTRODUCTION
Most estimates suggest that half of the Earth’s ice-free land surface has beentransformed by humankind and most of the rest is managed for human purposesover the past 10 millennia or so (Global Land Project, 2005). However, themagnitude, scale and pace of human intervention on land surface has markedly569

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Ecosystem Assessment, 2005). There still exist confusion and misunderstandingsof what is exactly meant “land-cover” change and “land-use” change (Agarwal etal., 2002; Verburg et al., 2006). Actually, the linkage between land-use and landcover change is emphasized that the impacts of land-use change and theircontribution to local and global change are mediated by land-cover changes(Turner et al., 1999). In other words, human intended land-use determinate theconversion of land-cover along with the natural land-cover change.
Land-use change put the negative impacts on the hydrological system, air quality,
soil properties, ecosystem processes and function. These changes, ultimately,
contribute to local, regional and global climate change through greenhouse gas
fluxes and surface Aledo effect etc. Land-use change issues, in-turn, increase thevulnerability of people to climatic, economic or socio-political perturbations.
Human have become ever more adept at appropriating and altering the land forhuman needs. Therefore, the way people use the land has become a source ofwidespread concern for the future of the world (Mohamed, 1999).
Questions of the causes and the consequences of land-use change have attracted
interest among a wide variety of researchers (Lambin et al., 2003; Ronneberger,
2006). At first, most land-use change research was focused on land-coverconversions (e.g., deforestation, urbanization) by a simple comparison of
successive land-cover maps (Irwin et al., 2001). However, land-use change is acomplex process including a number of interactions between associated drivers
and feedback from land-use change to these drivers (Pijanowski et al., 2005). The
driver factors of land-use change are described in detail by Lambin et al (2003)
including natural variability, economic and technological factors (e.g. rural
income, agricultural productivity), demography (e.g. population growth,
immigration), institution, culture and globalization related factors.
The complexity of land-use change process has called for the development ofland-use change model over the last decades (Briassoulis, 2000; Parker et al.,
2003; Pontius Jr et al., 2001; Turner et al., 1999; Veldkamp et al., 2001). It help
for better understand of land-use dynamics, to develop hypotheses that can betested empirically, and to make predictions and/or evaluate scenarios for land-use
planning and policy (Müller, 2003; Verburg et al., 2004a; Verburg et al., 1999). In
simple word, land-use change projection model have been developed to address
why, how, when and where the changes occurred. The development of land-use
change model may aim at one of the six main purposes: description, explanation,
prediction, impact assessment, prescription and evaluation of land-use change
process. However, the most important purpose of analysis land-use change is topredict future changes in land-use (Lambin et al., 2000; Veldkamp et al., 2001).
In this research, we aim at the appropriate framework for broad-scale land-use
modeling (the term “broad-scale” will be explained in the next section). The
reason is that modeling broad-scale land-use changes requires a robust method
which is able to seize the complicated interactions among the factors as well as
deal with the issue of data limitation. Review from the previous studies addressthat a large variety of concepts, approaches and techniques is already applied forbroad-scale land-use change research. Nevertheless, there remains the issue of
duplication within the land-use models. There are several models addressing
similar systems often are developed independently. Hence, this has the advantage
for our research of demonstrating a more organized modeling framework to avoid

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the competition and duplication between models. This framework is expected to
be flexible and transparent to apply for different case studies. We also proposed
the application of this framework to DakLak province in Vietnam. With thepotential for economic development, recently, DakLak has witnessed the increaseof population due to immigration from other provinces. The province has also
attracted more domestic and foreign investment. As a result, DakLak is facing theintense changes in land-use especially for infrastructure and agriculture
development. This calls for exploration of land-use model to support ofsustainable development in Daklak.
2. DEVELOPMENT OF FRAMEWORK FOR BROAD-SCALE LANDUSE MODELING
2.1 Broad-scale definition
The term “scale” may cause confusion because it has different meanings acrossdisciplines. Geographers define “scale” as the ratio of a distance on a map and thatsame distance in reality. Scientists from social sciences give opposite meanings to
the terms “scale”. To them, a large-scale study means it covers a large extent(correspond to small-scale maps of geographers), and a small-scale study is adetailed study covering a small area (are large scale, to use the geographer’s term)(Agarwal et al., 2002). From literature of land-use model, we figure out that mostmodels occupied the word “scale” as the extent of study area (Agarwal et al.,
2002; Heistermann et al., 2006; Lagarias, 2012; Schaldach et al., 2011; Valbuena
et al., 2010; Verburg et al., 2008). To avoid the confusion, instead of using theterm “large-scale”, we employ the term “broad -scale” which refers to the study
area with large extent. The broad-scale model can be subnational, national,
continental and global scale studies.
2.2 Reviews of broad-scale land-use models
Due to the variety of application purposes, each model was built to answer
specific questions. In this section, we will discuss about the common
characteristics as well as the methodological insights of representative models.
An inspection of the literature on broad-scale models reveals that, most of thetime, these are integrated models. At large extent, the high level of aggregation ofdata obscures the variability of situations and relationships calls for
multidisciplinary analysis. Therefore, no one model is capable of capturing thewhole range of land use change’s characteristic (Briassoulis, 2000; Lambin et al.,
2000; Verburg et al., 2004a). Integrated model, based on combining elements ofdifferent modeling techniques, has been widely used because of its capacity to
explicitly deals with temporal and spatial dynamics, and achieves a higher level ofmultidisciplinary approach (Michetti, 2012; Upadhyay et al., 2006; Verburg et al.,2009). Examples of such integrated land-use models include AGE, IMAGE,
IMPACT, CLUE, IIASA LUC and LandSHIF etc.
These models present different dimension of integration. The CLUE model, oneof the commonly used models, occupied the combination of different modelingtechniques: geographic-based and statistical analysis (regression analysis). The
The integration approach for broad-scale land use change prediction modelling
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projections, since the empirical relationships cannot necessarily be assumed
constant over long time periods. Another issue is that the CLUE model is not able
to reflect the macro-demand for land-use based on the given socio-economic
scenario. In some cases, the objectives of the authorities are used as the input dataof the land demands. In other researches, to solve the limitation of CLUE, somerelated models were introduced to calculate the land demands, for example GTAP
(Global trade Analysis Project) (Luo et al., 2010).
Meanwhile, AGE, IMPACT, IMAGE, IIASA LUC and LandSHIF represent for
the integrated model group in which the integration is defined as the combinationof sub-model adopted from a wide range of disciplines. However, almost modelsof this group, are not specifically developed for land use studies. IAM for the
Asian-Pacific region e.g. is designed to study impacts on the market and on
greenhouse gas emissions of land-using sectors rather than on land-use change
prediction (Matsuoka et al., 2001). The IMAGE, IMPACT models are specific for
agriculture sector (Strengers et al., 2004). And LandSHIFT model has the purpose
to provide a tool for assessment of environmental impacts of land-use change(Schaldach et al., 2011). Of these models, IIASA-LUC is currently the most fully
integrated model. Although this model incorporates many sub-systems,
interactions and feedbacks, it has become complex to operate and, above-all,difficult to parameterize due to the high data requirements for most countries(Fischer and Sun 2001). The other disadvantage of highly complex, integrated
models is that the degree and type of integration often appears to be subjective
based on the modelers disciplinary background (Agarwal et al., 2002). In somecases, highly aggregated assessments obscure the variability of geographic
situations through the high aggregation level of the data, and cause anunderestimation of the effects of land-use change for certain regions (Verburg etal., 1999).
Land-use models of regional, continental to global scale (broad-scale) require
specific methodologies that are different from local scale approaches. They haveto cope with data limitation for many variables and parameters, and for many
regions of the world and face the challenges of abstracting local land-use
decision-making to explain regional or global processes (Heistermann et al., 2006).
This issue infuses appropriate frameworks that influence modeling, from datacollection, to data analyses, to interpretation of results. The framework is a fully
integrated approach, qualitative modelling allows a focus on the system as awhole.
2.3. Appropriate framework for broad-scale land-use modelling
A number of review papers characterized integrated models by modular
components. Modularity might help facilitate modeling land-cover change byassigning a particular disciplinary aspect of the model to a separate module. We
found the majority of the modular models tended to consider multiple disciplines.
Judging from our review of the recent literatures, the integrated model framework
is mostly the combination of demand module and allocation module, respectively(Heistermann et al., 2006; Schaldach et al., 2011; White et al., 2012). The
demand module can be economic model purpose trend analysis, simple demandmodels (Kok et al., 2001) or complex multi-sectoral models are used

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ICUS Report 73(Heistermann et al., 2006; Verburg et al., 2008). This module is used for markets
and policies analysis and ultimately quantify demand and supply of land-intensive
commodities. The geographic module is occupied for the actual allocation of landuse. The geographic module have been supported by the rapid improvement of
remote sensing and GIS. This combination can help to utilize the strengths andminimize the weaknesses of individual model. For example, economic models canconsistently address demand and supply of land use. Yet, they are limited in
representing behavior of land use change. On the other hand, geographic models
are strong in capturing the spatial determination of land use and in quantifying
supply side constraints based on land resources. However, they lack the potential
to treat the interplay between supply, demand and trade endogenously.
Driving factors of land-use changeTime loop

Demand modelLand allocation model

Land-use at time t

Figure 1: General framework for land-use prediction model at broad scale
3. PROPOSE LAND-USE MODELLING FRAME WORK FOR DAKLAKPROVINCE
DakLak has the largest forest area in Vietnam and been at the high risk under thedevelopment pressure. The main problem in DakLak is the increase of population,
especially due to a high rate of immigration. Increasing population creates a
growing demand for agricultural land and forest products, which leads to adegradation of forest quality and a decrease in forest cover. The emergence of thelarge-scale cultivation of coffee is also one the most prominent which led to atransformation of the rural economy in the recent history of DakLak and inducing
massive land-use change and widespread deforestation.
Previously, some researches of land-use change were carried out in DakLak
province and some other researches in the Mekong river region encompassed
land-use change in Daklak in some extent. However, there has not been any
comprehensive model for land-use change in DakLak. Some crucial problems still
remain in the context of land-use change modeling for DakLak. Firstly, theprevious studies pointed out the limitation of excluding economy and policy
factors in land use change measurement. The research of Müller et al. (2004) put
effort to examine the complexity of natural, social and economic issues in two
district (Lak and Krong Bong) of Daklak, but only two factors, policy andtechnology, were taken into account.
The framework proposed in our research is expected to fill the gap in land-use
research in DakLak in particular and Mekong river basin in general. The
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Vietnamproposed integrated land-use model is the combination of System Dynamic Modeland GIS-based Model for land-use change prediction at DakLak. It can contributeas the technical assistance for DakLak to address future land use change. From themodel result, the researchers, policy makers and planners can gain initiative intheir land use planning and management for sustainable development.

Figure 2: Land-use modeling framework
3.1. System Dynamic model for land-use demandLand use is never static, but it is constantly changing in response to dynamic
interaction between drivers and feedback from land-use change to these drivers(Lambin et al., 2003). Case studies show that not all drivers of land-use change
and all levels of organization are equally important. The important step is how
best to represent these drivers in a model. This requires linking dynamically the574

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processes of land-use change to biophysical processes (Veldkamp et al., 2001).
Once a systems model has been constructed, what-if scenarios can be explored
more easily than with other modeling approaches that are not systems oriented.
The application of System Dynamic (SD) in land-use model was demonstrated inprevious study. Patuxent Landscape Model (Voinov et al., 1999) was designed tosimulate fundamental ecological processes on the watershed scale, in interaction
with a component that predicts the land-use patterns. The research of Luo et al.
(2010) described an integrated methodology in which the conversion of land use
and its effect model (CLUE), a spatially explicit land use change model, has beencombined with a system dynamic model (SD) to analyze land use dynamics at
different scales. This application of combination of SD and CLUE suggests that
this methodology have the ability to reflect the complex behavior of land use
system at different scales to some extent and be a useful tool for analysis ofcomplex land-use driving factors such as land-use policies and assessment of its
impacts on land-use changes.
SD methodology is a simulation technique that models large-scale, complex social
economic systems using stock and flows and explicitly including feedback loops.
It attempts to understand how physical processes, information flows andmanagerial policies interact to create the dynamics of the variables of interest (Liuet al., 2013). System components can be described by a set of state variables(stocks or reservoir), such as population or crop production etc. These statevariables are influenced by process (flow), such as the birth process or investment
process etc. The converter play an important role in the system as a rate at which
reservoir or stock contents changes.
Development of modeling tools allows us to build more sophisticated models. As
for SD analysis, STELLA with good documented references is our selection. It
provides a platform for dynamic modeling that has a very intuitive graphic userinterface and can be used to develop from simple to very complex models. The
structure of STELLA model on land use is drawn with the causality functions andfeedback loop structure between number of socio-economic and policy.

Figure 3: System Dynamic model for land-use demand in DakLak province

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3.2. ArcGIS Model builder for allocation module
For the allocation module, the driving factors will bed translated into suitability or
preference maps, which are a key component of the allocation. Such suitability
maps can be created using theory or expert knowledge of the land-use system,
empirical analyses or rules based on neighboring cells (Verburg et al., 2004b).
Using this suitability and the magnitude of change, an allocation algorithm willthen allocate the claims in the best suited areas. This allocation algorithm can be asimple cut-off value that selects the most suitable locations, but can also be amore sophisticated algorithm that takes the competition between different land
uses into account (Verburg et al., 2006).
ArcGIS Model Builder is selected to open black box of other land allocation
models. In Model Builder, the model is represented by a flux diagram in a graphic
user interface that facilitates to create, visualize, edit, and execute geo-processing
workflows. Model Builder is an easy-to-use application for creating and runningworkflows containing a sequence of tools. In addition, tools created with Model
Builder can be used in Python scripting and integrated ArcGIS with otherapplication.
4. CONCLUSION
Modeling involves making trade-offs between realism, precision and generality(Wainger et al., 2007). The more precisely a model captures a particular system,
the less likely it can be applied to another area (generality). As for the demand
module, the selection of factors and modeling the integration among factors
depend on the practical socio-economic circumstance of DakLak. Therefore themodel cannot directly applied to other study area. However, the research is
expected to demonstrate the potential of the integrated framework for broad-scaleland use modeling. The framework is designed in such a way that it is flexible inincluding other models and indicators if needed for a specific policy scenario
application. Our further task will be done to complete the System Dynamic model
as well as land use allocation module.
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China’s growing civil society
for disaster response
Xiaoge XU1, Koide OSAMU2, and Takaaki KATO3
1
Graduate Student School of Eng., The University of Tokyo, Japan
xuxiaoge@city.t.u-tokyo.ac.jp
2
Professor, School of Eng., The University of Tokyo, Japan
3
Associate Professor, ICUS, IIS, The University of Tokyo, Japan
ABSTRACTPrevious studies on civil society responding disaster suggest that, the disaster
often present an opportunity for civil society organizations (CSOs). This article
firstly examines the impact of the 2008 Wenchuan Earthquake on China’s civilsociety as a background, points out that the disaster served as a turning point topush existing CSOs into the field of disaster response, and gave birth to a numberof grassroots CSOs. Their participation in disaster relief and reconstruction work
indicates the changing disaster management mode of China, which used to bemonopolized by the state. Case study is used in the second section to illustrate thegrowth process of grassroots CSOs in the past five yeas, and their performance inthe field of disaster response. The case study indicates that transparency andprofessionalism are two factors contribute to the growth of grassroots CSOs,
while the cooperation between CSOs is still under dispute. Based on the findings
and issues, the author argues that Chinese government should further relax its
related regulation on CSOs to promote its self-sufficiency. Weak tie between the
CSOs should be established as a sustainable mode for disaster response.
Keywords: Disaster Response, Civil Society Organizations, China.
1. INTRODUCTION
Previous studies suggest disasters brought changes to civil society in Japan (Shawand Goda, 2004; Yatsuzuka, 2007), Turkey (Jalali, 2002; Kubicek, 2002), andIndia (Özerdem and Jacoby, 2005). On May 12th, 2008, Wenchuan Earthquake
attacked Sichuan Province in West China, led to a death toll of nearly 70,000(CNCDR and UNDP, 2009). Accompanying this tragedy was an unprecedented
participation of volunteers and civil society organizations (CSOs) in disaster relief
activities. Their participation changed the disaster relief mode of China, whichused to be monopolized by government. Scholars regard the year of 2008 as the“First Year of Civil Society” (Xu, 2008; Gao and Yuan, 2008; Xiao, 2009), whileother scholars hold an opinion that China is still on the way to civil society (Wang,2009). However, the dispute exists in the abstract concept of civil society. Both ofthem admit that CSOs have made significant progress experiencing the earthquake.
On the other hand, active roles of CSO responding disasters have been examinedin Kobe Earthquake (Atumi, Sugiman, Mori and Yatsuzuka, 1995), Mozambique581

October
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VietnamFloods (Moore, Eng and Daniel, 2003) and Indian Ocean Tsunami (Kilby, 2008).
In China, there are also many preliminary studies on CSOs’ roles to response
disaster (Gao and Yuan, 2008; Teets, 2009; Xiao, 2009; Zhu, Wang and Hu,
2009). However, most of these researches concentrate in 2008-2009, and focus on2008 Earthquake. On April 20th, 2013, a 7.0 magnitude earthquake struck Sichuan
again. The epicenter is located in Lushan, which is only about 200 kilometers
away from Wenchuan. The author was in Sichuan at that time to attend the fifth
anniversary forum of Wenchuan Earthquake, noticed that a number of CSO
members who actively participated in 2008 relief contributed themselves in theaffected areas again. Most of their organizations were born being touched by
Wenchuan earthquake after 2008. Thus, how did these CSOs perform in the lastdisaster, and how did these CSOs develop during the past five years?
This paper aims make clear to the growth of China’s CSOs, particularly in thefield of disaster response, during 2008-2013. Method of multiple case studies isused for in-depth and multi-faceted explorations. The author interviewed CSOs,
government officers, volunteers, and local victims from April to May in 2013. Inorder to be more objective, reports, news and other literature were also reviewed
to collect more comprehensive data. The paper is divided into three major sections.
In the first section, the impact of 2008 Wenchuan Earthquake on China’s civilsociety is presented as a background. Secondly, multiple case studies are used toillustrate the growth of China’s CSOs in the field of disaster response, by
examining their establishment motivations, organizational structure, evolution
process and activities in the past five years. The paper closes with a discussion of
the issues and lessons based on findings.
2. IMPACT OF 2008 EARTHQUAKE ON CHINA’S CIVIL SOCIETY
It is necessary to define civil society firstly because the contemporary meaning of
this term is contested. The definition of civil society used in this paper refers to thesphere of voluntary associations in which individuals engage in activities ofpublic consequence, distinguished from the public activities of government, andfrom the private activities of markets. CSO refers to an organization which is selfgoverning, not profit distributing, and formed voluntarily by members, including
NGOs, NPOs, volunteer organizations and foundations for the commonweal. One
fact need be mentioned is that relation between government and CSO in China iscloser than in Western countries. It is a consequence not only of unique social andpolitical context, but also the CSOs’ own understanding of their roles. Most CSO
leaders do not see their objective in confronting government or protecting society
from the state. Rather, they see the mission as fulfilling their citizen responsibility
in collaborating with government (Edele, 2005). In addition, more and moregovernment-organized NGOs (GONGOs) are detaching link from government inrecent years. For example, China Foundation for Poverty Alleviation (CFPA) has
sought to distance itself from its past identity as a GONGO, making efforts toprofessionalize and increase transparency and accountability. It is also famous for
its consistent support on grassroots CSOs. Therefore, although the focus of thispaper is the real grassroots CSOs, it is also impossible to exclude involvement ofthese transforming GONGOs in China’s civil society.

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CSO development in China has been quick. Economic reform process initiated in
the late 1970s created the possibility for China’s emerging civil society. Before
the commencement of economic reforms in 1978, the provision of social services
such as housing, health insurance, schools and pensions were all organizedthrough state systems related mainly to work units, resulted in no living space forautonomous organizations. Since the 1980s, the government has been establishing
GONGOs formally situated outside the state system in order to address social andenvironmental problems. At the same time, international NGOs (INGOs) began toenter China. The rapid economic growth led to emergence of a middle class withstronger economic level and higher education. They became the first generation
organizing autonomous groups. The first real grassroots CSO Friends of Nature
was set up in 1993. From then, more and more homegrown grassroots CSOs havebeen established. According to the official data from the Ministry of Civil Affairs(MOCA), at the end of 2007, China had almost 381,000 CSOs. The data only
indicates the number of registered CSOs which had registered at MOCA, while alarge number of unregistered CSOs are not included.
However, although the number is so huge, only few GONGOs and INGOs had
participated in disaster relief before 2008 earthquake (refer to Table 1). There arevarious factors contribute to absence of grassroots CSOs such as: (1) Insufficient
priority. The rapid economic development has led to a mass of social problems.
Comparatively, CSOs had paid more attentions to the issues such as poverty andchildren, identified these issues as their missions, rather than disaster response. (2)Shortage of funds. Only two GONGOs, Red Cross Society of China (RCSC), a
nominally NGO but actually a part of the central government, and China Charity
Foundation (CCF), another agency affiliated with MOCA, had been permitted toreceive donations and relief materials. Public foundations, most of which are
GONGOs, may raise fund publicly in peacetime, while had been excluded toreceive donations when disaster occurred until the enactment of Administrative
Measures for Disaster Relief Donations on April 28, 2008. Most of grassroots
CSOs had survived depending on the aid from INGOs, lacking of ability to carryout long-term activities in affected areas. (3) Political pressure. Although the
National Preparatory Plan for Disaster Relief and Emergency Response issued by
the State Council in 2006 had encouraged participation of CSOs nominally, there
had been no approach available in practice. For example, in January 2008, when asnow disaster occurred, some grassroots CSOs located in Guangdong tried toparticipate in disaster relief, but refused by local government. Instead, themembers were permitted to take actions in the name of individuals (Yu, 2010).
Wang, the former director of MOCA disaster relief department, describes thecharacteristics of disaster management system in China as: “unified led by the
Party and government, divided responded by each department, and managed at
different administrative levels”. From the interview of a local government officer
in Sichuan, disaster relief “is the responsibility of government. The participationof other organizations outside the state system would disturb the social order.” Insummary, before 2008 earthquake, the disaster response used to be monopolized
by the state in China.
Wenchuan Earthquake triggered changes from May 12th, 2008. After the disaster,
outpour of citizens provided their aid and funds to the affected areas. They helped

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Vietnamwith health, sanitation, medical aid, food distribution, and security in days andmonths following the quake. Official data from MOCA indicates that more than
3,000,000 volunteers contributed their time and efforts in the disaster affectedareas until the end of 2008; donations for emergency relief and post-disasterreconstruction achieved 76.7 billion Yuan, in which donation from the individual
reached 45.8 billion Yuan. It is the first time that individual donation exceeding
donations from the enterprises historically (Charity and Donation Information
Center, 2009). The nationwide participation ignited CSOs’ enthusiasm. According
to an incomplete statistics survey, more than 264 CSOs have taken actions in
disaster relief and reconstruction work (Zhu, Wang and Hu, 2009). They havecarried out projects in the field of emergency rescue, health care, reconstruction of
housing, livelihood support for residents, etc. Their behaviors are regarded as “thefirst exposition of the Chinese CSO sector” by a CSO leader.
The disaster also featured an unprecedented large-scale cooperation of CSOs. It isvery significant because there had been almost no autonomous network andumbrella bodies due to legislative restrictions in the past. According to the reportfrom NGO Research Center (2006), only a bit more than 6% of CSO stakeholders
thought that CSOs were active in sharing information amongst each other; nearly
40% of stakeholders thought that Chinese CSOs had few or none cooperation with
one another; nearly nobody thought they cooperate very well before 2006. Mostof the CSOs began to choose cooperation in disaster relief because the devastating
earthquake had made them recognize their limited capacity to address this severe
damage. On May 13, a joint declaration sponsored by Narada Foundation, CFPA
and Friends of Nature called on CSOs to unite to response disaster attracted 164
CSOs nationwide. A survey of 70 CSOs indicates that 58.6% of the respondents
belong to an alliance with 3 or more than 3 CSOs (Wang, 2009). According to an
incomplete statistics investigation, there were 19 CSO-networks formed after theearthquake (Zhu, Wang and Hu, 2009). One example is Sichuan United Office for
NGO Disaster Relief (SUND), which was set up on a few hours after theearthquake. Although it was closed on May 30, more than 100 organizations hadjoined using the internet. It had raised materials of 1.8 million and mobilized
thousands of volunteers. Another network located in the disaster affected areas is
Sichuan 512 Voluntary Relief Service (SVRC), which was established on May 15
to united 34 NGOs, including 18 homegrown CSOs, 6 INGOs, 4 foundations, 3
volunteers associations and 3 internet-based associations. Different SUND, SVRC
was restructured after the emergency period of 2008 earthquake. Until now, it has
still played the active roles as a regional platform to share information andcoordinate disaster relief efforts among local CSOs. There were also some CSOnetworks located outside the affected areas helping to gather supplies donated byenterprises and transport them to Sichuan, such as Xintuofeng Action, a smaller
network involving One Foundation and 4 NGOs located in Shanghai.
Moreover, the increasing need of victims could not be met only by governments,
which had been also severely destroyed in the earthquake. The pressing shortageof relief personnel and resources led to the welcome attitude of national and local
government. In addition to RCSC and CCF, 18 public foundations were permitted
to receive donation after this disaster. Some public foundations such as RCSC andChina Youth Development Foundations, and some private foundations such as

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Narada Foundation, began to realize the importance of grassroots organizations’participation in disaster management after 2008 earthquake. On the one hand,these existing CSOs began to take actions in the following disasters; on the other
hand, they have contributed to the birth of new-established CSOs providing themfunds. Touched by 2008 earthquake, a number of grassroots organizations in thefield of disaster response were established as stated in Table 1. For example, after
the closure of SUND, one leader established NGO Disaster Preparedness Center(NDPC). Beichuan China Heart Association is another CSO located in Sichuan
evolved from an embryonic temporary association of volunteers after earthquake
to deal with disaster relief. The influence is not only within Sichuan, but alsobrought impact on the regions outside affected areas: 2 volunteers worked in
SUND went back to their hometown and established Ying Team located in Yunnan
Province. Will Gathering Disaster Mitigation Center was also established in
Guizhou Province by a volunteer experiencing 2008. In the next section, a casestudy of One Foundation is presented. One thing need to notice is that, the casestudy cannot represent all of these CSOs. Actually, within the limited space for
CSOs in China, these CSOs must have their own unique advantages.
Table 1: Part of CSOs involving disaster response in China
Type

Name

Founded
Time*
1991
1987
1989
2001
1950
1994
1989

Time into
DR field
1991
1991
2008
2008
1987
1998
2002

Oxfam
Tzuchi Foundation
INGO
Save the Children
Mercy Corps
RCSC
AgencyCCF
CFPA
GOChina Charities Aid
1981
2008
NGO
Foundation for Children
PublicChina Youthfoundation
Development
1989
2008
Foundation
One Foundation
2007
2008
China Social
2007
2008
PrivateEntrepreneur Foundation
foundation
Narada Foundation
2007
2008
National
Huaxia Commenweal
Grass
2010
2010
organization Service Center-roots
NDPC
2008
2008
CSO
Yixing Team
2008
2008
Regional
Will Gathering Disaster
2008
2008
organization Mitigation Center
Beichuan China Heart
2008
2008
Association* For INGOs, the time indicates they began their activities in China Mainland.

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3. CASE STUDY: GROWTH OF CSO RESPONDING DISASTER
As a case study, One Foundation is described in details in this section, while other
CSOs cooperated with it such as NDPC will also be involved. Given the relative
young age of these organizations, it may be too early to proclaim success or
failure, while much can be learned by understanding their growth process during
the past five years.
3.1 Establishment motivation
One Foundation was founded by international kung fu star Jet Li in 2007. The
motivation to establish such an organization primarily involved in disaster relief
activities is related to his own survivor experience in 2004 Indian Ocean Tsunami.
On Dec 25th, 2004, he was in the Maldives and almost lost his children during an
island vacation. Touched by this life-shaking experience, he announced his plans
to start the One Foundation a few days later. The formula is very simple: one
person + one Yuan per month = one big family. However, he did not quite know
where to begin at that time (Li, 2008). The status of a public foundation is needed
to be authorized to raise funds publicly, but it was difficult to register as a public
foundation without any connection with the government at that time. Finally, he
had to set up an attached special project under RCSC in 2007, named as the Jet Li
One Foundation Project to share its right to raise funds publicly, and registered asa private foundation with the named of Shanghai-based Jet Li One Public Welfare
Foundation to legitimize its legal entity in 2008.
3.2 Performance in Wenchuan Earthquake
The Wenchuan Earthquake is the first massive disaster One Foundation faced
after its establishment. The identity under RCSC made it become the only
grassroots organization to receive public donations after the disaster. Within 3days, the donations had reached 60 million Yuan, excluding mountainous reliefmaterials donated from enterprises and individuals. It was a challenging task forthis young organization with 13 staffs totally, in which only 3 staffs in Shanghai
office to manage the donations at that time. The shortage of personnel pushed itcooperate with 4 NGOs located in Shanghai on May 14th. Their united action wasnamed as Xintuofeng Action. All of the information, such as lists of materials andreceipted signed by local victims were open on the internet, and supervised by the
public. The high transparency, different from the government and GONGOs in thepast, earned One Foundation a growing reputation afterwards. According to its
annual financial statement audited by Deloitte, the donations earmarked for
Wenchuan Earthquake had reached 96,891,706 Yuan until the end of 2008. The
abundant funds made it possible to carry out continued activities in the disaster
affected areas for reconstruction. Until April 30th, 2011, three years after theearthquake, One Foundation had put about 108,021,201 Yuan into affected areas,
including 42 projects covering education, poverty alleviation, community
development, health care and many other fields. It claims more than 5 million
people had been directly and indirectly benefited in its open report published on
May 12, 2011.

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The outstanding performance of One Foundation pushed it becomes the firstgrassroots public foundation without government backing. In December of 2010,
One Foundation was eventually able to register as a public foundation in
Shenzhen, where the registration regulation had been reformed and relaxed. Bothof the identities before along with funds, projects and personnel were integrated to
the Shenzhen One Foundation Charity Fund.
3.3 Current system for disaster response
The legal status as a public foundation further guarantees the abundant fund for
rapid development. Two networks, One Foundation Rescue Alliance (OFRA) and
One Foundation United Rescue (OFUR), as well as five Disaster Preparedness
Warehouses (DPW) located in disaster-prone areas have been established as its
main channels to response disasters during the past five years. OFRA was set up
to unit 30 rescue volunteer teams on May 12th, 2009. It is an open system towelcome groups, as well as the individuals who are enthusiasts in outdoor sports.
At present 163 voluntary rescue teams has joined; the number of volunteers(includes the member of teams and individuals) has reached nearly 5000.Anothernetwork, OFUR, was set up to unite 11 regional CSOs involving disaster response
on Feb. 23rd, 2012, including NDPC and Yixing Team. OFUR is seeking to build
a dynamic, interconnected response mechanism to carry out emergency disaster
relief, reconstruction work and routine disaster prevention education. In the eventof disaster, the local partner CSO establish a working platform and assume theresponsibility of coordinating and providing services, while other partner agencies
support operations and resources. Different from OFRA, members of OFUR are
all in the forms of organizations. They participate in all the periods of disastermanagement cycle: response, recovery, mitigation and preparedness.
In the recent years, OFRA and OFUR have played their active roles in Sichuan,
Qinghai, Guizhou, and Yunnan Province for earthquakes, mudslides, droughts,
floods and other natural disasters. The network of regional teams guarantees thequick response for disaster. In the case of 2013 Lushan Earthquake, the leader of
OFRA Sichuan Team was feeling the shakes and immediately organized local
team for preparedness. 10 minutes after the quake, pioneering team departed tothe affected areas and arrived 2 hours later. It is a disgrace for my profession if wecannot arrive the disaster affected areas within 24 hours.” A member said. For
reference, the response timeline is presented in Table 2. At the same time, OFUR
partner proceeded to deliver relief materials from DPW in Sichuan, Guizhou andShaanxi Province. The Emergency Response Plan was officially announced earlymorning 4 am, April 21st: Stage One for Rescue, with rescuing of lives andsalvaging of materials as main focus in the first month after the disaster; Stage
Two for Relief, the settlement of disaster victims within 4-8 weeks, ensuring thedelivery of basic living necessities; Stage Three for Rebuilding, within 1-2 years
after the disaster, providing psychosocial rehabilitation facilities and services forpost-disaster children. Within 72 hours after the disaster, emergency rescue andtransportation of the injured is the focus. During the two days after Lushan
Earthquake, OFRA rescued 20 people serious injured, 56 people lightly injured,and transported more than 600 people injured. A total of 182 personnel was
dispatched in the disaster area until April 27th.

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Table 2: Quick response of OFRA after Lushan Earthquake on April 20, 2013
Time
08:02
08:12
10:05
10:08
10:30
14:40
16:40
22:45

EventsEarthquake occurred.
2 members departed as reconnaissance group.
The first two pioneer members arrived in affected areas,
returned feedback to the headquarters and began rescue.
1st group, Sichuan rescue team, departed for affected areas
with dogs and equipments.
2nd group, including 6 rescue teams from other provinces:
Hebei, Henan, Guangxi, Beijing, Qinghai and Yunnan had
been assembled, departed to the affected areas.
1st group arrived. Field command was set up.
Logistical support team for 1st group arrived.
Henan rescue team of the 2nd group arrived.

4. FINDINGS AND ISSUES
Characteristics of One Foundation are summarized as the following:
TRANSPERANCY Different from the government-backed public foundations,
One Foundation has adopted its transparency mechanism from its establishment.
All the public donations to One Foundation is hosted by China Merchants Bank,
audited by Deloitte, and accounted by KPMG. List of relief materials, financial
statements, procurement notices and invoices can be checked on its official
website. The public has expressed distrust of GONGOs, using the checkbooks tovote for the bottom-up CSO over the government-backed RCSC. A recent survey
by newspaper China Youth Daily reflects that 60% of interviewees expressed trustin NGO, while only 10% trusted GONGO. After 2013 Lushan Earthquake, One
Foundation has received donations worth 28.5 million Yuan until May 12th, 2013.
PROFESSIONALISM OFRA members have outstanding capabilities in various
fields such as diving, flying, carving, mountaineering, psychological counseling,cross-country driving, and radio communication and so on. Some of them hold theinternational rescue license, and have participated in international operations.
Moreover, most of the member teams are equipped with professional tools
including satellite phones, SUVs, rescue dogs and generators. The professionalism
is also reflected in the procedure. Once a disaster occurs, members are assembled
following an agreed process: in order to avoid unnecessary waste of personnel, thereconnaissance team is sent out as the pioneer firstly, while others are standby.
The regional leader decides whether to send follow-up team according to the
feedback from the reconnaissance team. In the case of Lushan Earthquake in 2013,
the leader of Sichuan Team only sent two members for damage assessment at the
beginning. The reconnaissance returned the message two hours after the quake,
indicate that the situation is very serious. Then, the leader immediately sent thesecond team to the affected areas, followed up by the third.

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LINKS WITH LOCAL CSOs Members of OFRA are distributed in 30 provinces,while members of OFUR are distributed in 11 provinces. The alliance is not only
able to response the emergency events in each region, but also to coordinate theinter-provincial relief efforts. The network of local volunteers and organizations
also guarantees its quick response for disaster. However, it is not easy to maintainthese independent CSOs in the peacetime. Members of OFRA usually have theirown jobs, and join in the actions of rescue voluntarily. They participated only theperiod of emergency rescue, while the connections in OFUR are tighter because
the members of OFUR participated in all periods of disaster cycle. Although the
CSOs have accumulated experience in disaster relief over the years, they are stillfacing problems such as insufficient staffs for community disaster preparedness
training, lack of daily office expense. The leader of NDPC, who is the first person
to come up with the idea of United Rescue, openly expressed his dissatisfaction to
the media. “One Foundation hopes us to wear their uniforms in the disaster relief,
but our organizations also need our own influence to develop ourselves. Funds
received from only one foundation is not enough to maintain an organization. We
have to find other foundations for cooperation.” The founder of Yixing Team also
expressed his opinions as “Some foundations see local CSOs as merely a shortterm instrument. They hope they can all on organizations to be effective in adisaster even without providing them with support on an ongoing basis.”
5. CONCLUSIONS AND DISCUSSIONSThe 2008 earthquake serves as a turning point for many existing CSOs to intake
the disaster response to their main fields, and also offers opportunity for thosegrassroots organizations established in a bottom-up way. Case study indicates thattransparency and professionalism should be the future direction for those powerfulorganizations, while its link with local organizations is still under disputation.
Localized and community-based disaster prevention and disaster mitigation
measures tend to provide the most effective and rapid disaster relief to response
the more complicated natural disaster. The mode of CSO-network is a good vision
for a sustainable development of disaster affected community, but realizing it stillrequires further considerations. Galaskiewicz (1985) argued while the hierarchicalmodels of resource allocation and movement emphasize the power during interorganizational transactions. Thus, to avoid the possible unequal connections
among member organizations, the problems such as insufficient staff and shortageof funds have diminished the development of grassroots CSOs should be firstly
addressed.
Chinese government encourages CSOs to participate in disaster response in manystatements. However, there are not operational laws formulating mechanism andprocedure on the participation of CSOs so far. Moreover, the regulation on public
fund-rising is so strict even celebrities as well-connected as Jet Li, have a difficult
time acquiring public foundation status. As the first step, government need further
relax the regulation on public foundation to support these grassroots local CSOs.
And then, when the local CSOs become self-sufficient and more independent, aorganizational structure like OFRA with weak ties can be established to be moreequal and effective.

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REFERENCES
Charity and Donation Information Centre, 2009. 2008 Annual Report of Chinese
Charitable Contributions. Retrieved from http://www.mca.gov.cn
CNCDR, and UNDP, 2009. The Research Report of the Sichuan Earthquake
Emergency Relief. Retrieved from http://ch.undp.org.cn/downloads/CPR/2.pdf
Edele, A., 2005. Non-Governmental Organizations in China. Centre for Applied
Studies in International Negotiations, Geneva.
Gao, B., & Yuan, R. (editors), 2008. The Blue Book on Chinese Civil Society
Development. Peking University Press, Beijing.
Galaskiewicz, J., 1985. Interorganizational relations. Annual Review of Sociology,
11, 281-304.
Jalali, R., 2002. Civil society and the state: Turkey after the earthquake. Disasters,
26, 120-139.
Kilby, P., 2008. The strength of networks: the local NGO response to the tsunami
in India. Disasters, 32, 120-130.
Kubicek, P., 2002. The earthquake, civil society, and political change in Turkey:
assessment and comparison with Eastern Europe. Political Studies, 50, 761-778.
Li, J., 2008. My turn: the tsunami that changed my life. Newsweek, 152 (14).
Moore, S., Eng, E., and Daniel, M., 2003. International NGOs and the roles of
network centrality in humanitarian aid operations: a case study of coordination
during the 2000 Mozambique floods. Disasters, 27, 305-318.
NGO Research Center of Tsinghua University, 2006. A nascent civil society witha transforming environment. CIVICUS civil society report, Beijing.
Özerdem A., and Jacoby T., 2005. Disaster Management and Civil Society:earthquake relief in Japan, Turkey and India. I.B.Tauris, London.
Shaw, R., and Goda, K., 2004. From disaster to sustainable civil society: the Kobe
experience. Disasters, 28, 16-40.
Tweets, J., 2009. post-earthquake relief and reconstruction efforts: the emergenceof civil society in China? The China Quarterly,198, 330-347.
Wang, M (editors), 2008. Emerging Civil Society in China, 1978-2008. Social
Sciences Academic Press, Beijing
Wang, M (editors), 2009. Reports on the Civil Society Action in Wenchuan
Earthquake: China NGOs in Emergency Rescue. Social Sciences Academic Press,
Beijing.
Xiao, Y., 2009. Wenchuan Earthquake Witnesses: the Growth of China’s Civil
Society. Peking University Press, Beijing.
Xu, Y., 2008. The first year of Chinese civil society, NPO Journal, Vol 4, 1-5.
Yatsuzuka, I., 2007. Recording volunteer activities after the Great Hanshin
Earthquake and their transition: their functions and possibilities from theviewpoint of social change. The Japanese Journal of Experimental Social
Psychology, 47, 146-159.
Yu, X., 2010. How Chinese Civil Society Organizations involved in Responding to
Climate Disasters. Friends of Nature, Beijing.
Zhu, J., Wang, C., and Hu, M., 2009. Obligation, Action, and Cooperation: Case
Studies on NGO’s Participation in Wenchuan Earthquake Relief. Peking
University Press, Beijing.

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Survey on current systemfor disseminating disaster early warning
by cell phones in Japan
Takanori SAWARA1, and Miho OHARA2
1
Graduate Student, Graduate school of Eng., the University of Tokyo, Japansawara@iis.u-tokyo.ac.jp
2
Associate Professor, International Center for Urban Safety Engineering (ICUS),
Institute of Industrial Science, the University of Tokyo, Japan
ABSTRACT
Dissemination of disaster early warning to cell phone users is becoming more
effective for disaster mitigation and preparedness as a lot of people are getting
their own cell phones. In Japan, the ratio of the cell phone users exceeded morethan 90-percent of the total population. Now, two kinds of systems fordissemination disaster early warning to cell phone users are popular in Japan.
One is cell broadcast service called “Area-mail” that is provided by several
cellular service providers to send e-mails informing disaster early warning to all
the cell phone users in the high risk area. Under this system, earthquake early
warning and tsunami warning are automatically sent to all the cell phone users.
In addition, local disaster information such as evacuation counsels is also sent if
local governments adopt this system. The other system is e-mail service by local
governments that provide disaster warning or information to the people who
registered their e-mail addresses through the website in advance.
This research aims to understand current situations of both systems fordisseminating disaster early warning by cell phones in local area. A questionnaire
surveys to the 33 local governments in Kanagawa Prefectures were conducted toknow how both systems are used for information dissemination between
governments and local residents. The survey revealed that both systems were
widely adopted by many local governments in Kanagawa Prefectures. Theirtarget disasters and criterion for sending warnings, frequency of their emergency
and daily uses were verified. Especially, e-mail service with pre-registration by
local governments was frequently used for various purposes such as disaster
drills or sending information on normal events. Finally, issues to improve thesesystems were discussed based on the survey results.
Keywords: information dissemination, disaster warning, cell phone
1. INTRODUCTION
Dissemination of disaster early warning is effective for disaster mitigation andpreparedness. In Japan, local governments have introduced many measures todisseminate disaster early warnings.

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One of the major systems for disseminating disaster information is "disasterprevention administrative radio system." When a local government sends disaster
information by the radio system, the information is disseminated instantly by
loudspeakers and radio transmitters. Other measures to disseminating theinformation are local government official websites, official accounts in a social
networking service such as twitter, community radio by the governments, official
channels in cable TV, and data broadcasting system in local television companies.
In addition, some local governments can disseminate the information to cell
phones of local residents. Disseminating disaster early warning to cell phone users
is becoming more effective. Two kinds of systems for disseminating information
to cell phone users are becoming popular in local governments in Japan.
One is cell broadcast service called “Area-mail” that is provided by several
cellular service providers to send e-mails informing disaster early warning to all
the cell phone users in the high risk area. Under this system, earthquake early
warnings and tsunami warnings are automatically sent to all the cell phone users
without residents’ registering their e-mail address. In addition, local disaster
information such as evacuation counsels is also sent if local governments adopt
this system. To send local disaster information by this system, local governments
send text messages to each cellular service providers.
The other system is e-mail service by local governments that provide disasterwarning or information to the people who registered their e-mail addresses
through the website in advance.
As local governments can decide the use of the two systems for cell phone users
and the contents of the information, there are some differences among local
governments to the use. This research aims to understand current situations andthe difference between both systems.
2. METHODOLOGY
2.1 Outline of questionnaire procedures
To understand current situations of two systems for disseminating disaster
information to cell phone users, a questionnaire survey to almost thirty three local
governments in Kanagawa Prefectures were conducted to evaluate the efficiency
of both systems for information dissemination between local governments andresidents. The questionnaire was sent by fax to disaster prevention section orcrisis management section in each local government’s office before the beginningof August 2013, and twenty two local governments answered.
2.2 Contents of the questionnaire
Table 1 provides the information of all questions on the questionnaire. At first, allavailable media to disseminate disaster information for local governments are
asked in the questionnaire survey. If a local government has adopted either cellbroadcast system or e-mail system with pre-registration by the local government,
the current situation such as the contents of information sent by the systems,
history, frequency of their usages, and problems of the systems which isrecognized by the local governments was asked.

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Table 1: Contents of the questionnaire

Current situationsof information
dissemination

Cell broadcast
serviceE-mail service
by localgovernments

All available media to disseminate disaster information
The number of outside loudspeakers for disasterprevention administrative radio system
The number of individual receivers in residents’ houses
for disaster prevention administration radio system
Current situation of adopting the national early warning
system which is called “J-ALERT”
Adoption of the service by major cellular service
providersContents of disseminated information by the service
Comparison of the use between disaster prevention
administrative radio system and cell broadcast service
Past use of the service during disasters
Past use of the service for drills
Problem of the service
Common question asked by residents
Adoption of the service by the local governments
The number of registered people
Contents of disseminated information by the service
Comparison of the use between disaster prevention
administrative radio system and e-mail service
Frequency of sending e-mail by the service
Problem of the service

3. RESULTS
3.1 All available media for local governments
Based on the answers obtained from local governments in Kanagawa Prefecture,most of the local governments can use multiple media to disseminate disaster
information. Table 2 provides the information regarding the media adopted by
local governments. It shows that almost all the local governments use
loudspeakers for disaster prevention administrative radio system and that
information dissemination for cell phones is also commonly used by local
governments.
Table 2: Available media for local governments (N=22)
Media
Loudspeakers for disaster prevention
administrative radio system
E-mail system by local governments

Num. of local
governments

Percentage

21

95.5%

20

90.9%

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Official website of each governments
Cell broadcast service
Data broadcasting by local TV
Community radio
Social networking service (Twitter etc.)
Cable TV

19
15
12
10
9
8

86.4%
68.2%
54.5%
45.5%
40.9%
36.4%

In two systems for information dissemination for cell phone users, cell broadcast
service is used by 68.2% of local governments, and e-mail system by local
governments is used by 90.9% of local governments. Figure 1 shows which cityuses two systems. Big cities such as Yokohama, Kawasaki, and Sagamihara tend
to use both systems.

Figure 1: Available system for disseminating information to cell phones
3.2 Contents of disaster early warnings for cell phones
Survey revealed the difference of contents between the information sent by cellbroadcast service and by e-mail system with pre-registration by local governments.
Figure 2 shows the contents disseminated by the systems.
Information surrounded by red lines is urgent disaster early warnings
disseminated by both systems. For example, many local governments use both
systems to disseminate evacuation orders, evacuation advisory, Tokai Earthquake
prediction information, and emergency warnings which are issued to alert people
to the significant likelihood of catastrophic disasters. Missile information andsediment disaster bulletins which are issued at the high risk of sediment disasterare disseminated by both systems in many cities or towns. Since heavy rain
warnings and flood warnings are frequently issued, less local governments
disseminate the warnings by cell broadcast system.
Information surrounded by green lines is earthquake early warnings and tsunami
warnings. Approximately forty percent of local governments disseminate thesewarnings by e-mail service, but these warnings are disseminated to all areas likely
to be affected by earthquake or tsunami.
On the other hand, e-mail service by local governments is used for disseminatingother kinds of information which is not urgent and not related to disaster such as

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photochemical smog, crime, request for searching for person, fire, and public
relations by governments. The information is surrounded by orange lines in the
figure 2. The information is not disseminated by call broadcast service at all.

Figure 2: Contents of disseminated information
3.3 History and frequency of past use
Result of survey revealed that frequency of usage is completely different in two
systems. Figure 3 shows how many times cell broadcast service was used by each
local governments in the past. This service has been used only three times at most.
Furthermore, more than a half of all the local governments which introduced theservice have never used the service.

History of cell broadcast service

0%

10%

20%

30%

40%

50%

60%

70%

80%

90% 100%

3 times
2 times
1 time0 timeFigure 3: Number of times when cell broadcast service was usedby each local government
On the other hand, e-mail service by local governments has been used more
frequently than cell broadcast service. Most local governments introduced thesystem before the introduction of cell broadcasting service. Figure 4 shows thefrequency of e-mail sent by e-mail service by local governments. This service isused at least once a month in almost all of local governments.

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0%

10%

20%

30%

40%

50%

60%

70%

80%

90% 100%

EverydaySeveral times a week
Several times a month
Several times per a half of year
Several times a year

Figure 4: Frequency of e-mail sent through e-mail service
by each local government
3.4 Problems in the two services
Survey has also elaborated the problems of the two systems which are considered
by local governments, as shown in figure 5 and 6.
One of the most serious problems of cell broadcast service is a time-consuming
work to send the same message to each cellular service provider. If a local
government sends a message to cell phones by cell broadcast service via threecellular service providers, the staff has to send the same message three times toeach cellular service provider. Another problem is that some cell phones cannot
receive the information by the system. In addition, it may be difficult todisseminate information to elderly people because the ratio of elderly cell phoneusers is low. Another problem is that local governments cannot designate specificarea at high risk. When a city decides to use the system for information
dissemination, information will be disseminated in the whole city regardless ofrisk. For example, tsunami warning may be disseminated in mountainous area.
E-mail service by local governments has different problems. The most serious
problem of this system is that the number of registered residents is limited. Basedon the answers obtained from local governments, the average ratio of registeredpeople to the total population of each city or town is 8.8 percent, although someregistered people are not residents in the city or town. If urgent disaster early
warnings are sent by the e-mail service, limited people will receive the warnings.
Local governments cannot increase the number of registered residents easily
because residents decide whether they register their e-mail address or not. Anotherproblem is that it takes long time to send e-mail to all registered people. When lotsof e-mail is sent at the same time, the e-mail will be likely to delay. In addition toit, the limitation of the office staff is also a problem. When members of staff in a
local government’s office are not enough such as night time, they cannot send email to registered people.

Figure 5: Problems of cell broadcast service

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Figure 6: Problems of e-mail service by local governments
4. CONCLUSION
Current survey has revealed that both systems were widely adopted by many local
governments in Kanagawa Prefectures. Their target disasters and criterion forsending warnings, frequency of their emergency and daily uses were verified.
Especially, e-mail service with pre-registration by local governments was
frequently used for various purposes such as disaster drills or sending information
on normal events. Cell broadcast service is used only for urgent situations.
To improve these systems, cellular service providers should adapt new cell phone
to cell broadcast service. Secondly, information disseminating area should be
divided into small areas. In terms of local governments, cell broadcast service
should be used more actively as a drill. This service has never been used in somecities or towns, so residents don’t understand the system. To improve e-mailservice by local governments, an increase of registered residents is important.
Public relations of this service should be done and the procedure of registration
should be made more user friendly.
REFERENCE
Miho OHARA, Akiyuki KAWASAKI, Shinya KONDO, Atsushi TANAKA,
2012. A Survey on Information Dissemination by Area-mail during Storm
Disaster due to Typhoon Talas in September 2011: Quick Report on Survey inMiki-cho, Kagawa Prefecture, Seisan Kenkyu, Vol 64, No 4, 553-556.
Japan meteorological agency, Weather, Climate & Earthquake Information, from:http://www.jma.go.jp/jma/indexe.html
NTT docomo Inc., 2013, the user policy for “Area-mail” service.
Fire disaster management agency, 2013. A guidance for developing disaster
information dissemination method.

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Assessing recovery: existing practices
and evaluation measures

1

Yasmin BHATTACHARYA1 and Takaaki KATO2
Graduate Student, Department of Urban Engineering, the University of Tokyo,
Japan,
yasmin@iis.u-tokyo.ac.jp
2
Assistant Professor, ICUS, IIS, the University of Tokyo, Japan

ABSTRACT
Recovery is an essential part of the disaster cycle and perhaps the one that
requires immense combined efforts from several parties, more so compared toother phases such as mitigation and preparedness measures. It is also an area
which requires considerable study and contemplation due to its process andimpacts being long-term. However, this is exactly where the complexity arises;
recovery is also that much harder to study and define because of its long-term
nature and impact. This paper is a literature review of the field of disaster studies
in regards to recovery: when it emerged; how it was defined and conceptualized;
and how it has developed to the present day. It will further focus on the aspect of‘quality’ of recovery and provide perspectives on how recovery manuals andguidelines offer the assurance of quality in their approaches. Existing measures
for assessing recovery are also discussed in brief and some future considerations
for evaluating recovery are identified.
Keywords: recovery, disasters, methodologies
1. INTRODUCTION
The term “Recovery” is so often used and applied to so many contexts, that it is amajor dilemma to try to define it let alone measure and evaluate it. Furthermore, amajor obstacle in the field of recovery research is the long-term nature of recovery
embedded within the broader context of regional development, which makes it
even more difficult to track, measure and analyze.
This paper conducts a literature review on all of these aspects to understand theexisting methods of analysis and the difficulties that arise when following
manual-oriented approaches to recovery. Thus, it separates the ideologies from therealities and further aims to observe what have been highlighted as crucial to themethods of assessing recovery to give a foundation for future development ofrecovery assessment measures.

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2. DEFINITION OF RECOVERY
Though most of the defined phases in the disaster cycle lack a specific definition(Neal 1997), ‘recovery’ is perhaps the most vaguely defined concept among them.
As Neal (1997) notes, recovery research did not receive much attention in theearly stages of disaster research and thus it is still in its nascent stages ofdevelopment (with only about twenty years of history).
2.1 Sub-categories of Recovery
Although across literature, there are various usages of recovery, so far reviews
have identified these major categories: reconstruction, restoration, rehabilitation,
restitution, repopulation, redevelopment and recovery (Quarantelli 1999; Neal
1997; Aldrich 2012).
Overall differentiation of these categories as shown by Neal (1997) andQuarantelli (1999) are as follows: While ‘Reconstruction’ focuses exclusively on
the rebuilding of the physical structures, ‘Rehabilitation’ considers more of thesocial aspects. Moreover, ‘Restoration’ has a stronger emphasis on bringing thesociety back to the pre-disaster status whether it be the physical or social structure.
‘Restitution’ implies legal actions to return to a former state of affairs, while‘Repopulation’ is dependent on statistical data of human occupancy. Further tothis, ‘Redevelopment’ stresses the facilitation of a new or reformative
development as opposed to the restoration-oriented thinking, while ‘Recovery’signifies bringing back the post-disaster situation to some level of acceptability
which may or may not be the same as the pre-disaster level.
2.2 The Problem of Aim
Furthermore, while ‘prevention & mitigation’, ‘preparation’ and ‘response’ canstill provide a clearer indication of what to aim for, the understanding of‘recovery’ is troubled by its lack of direction. Its aim is an unidentifiable entity(because “there is no common solution” (Kato et al. 2013)) which is subject toconstant criticisms by insiders and outsiders alike due to either theirdissatisfaction or incomprehension. In addition, its complexity is furthered by thefact that it is a long-term process and therefore unable to be properly defined as ashort-term project which is achievable and thus measureable.
3. EXISTING MEASUREMENTS OF RECOVERY
As mentioned previously, the measurement of recovery is immensely difficult due
to the complexities involved as well as its long-term nature. Still, in looking at
long-term recovery, some form of measurement is required to evaluate recovery.
The following are some of the existing methods for evaluating the quality ofrecovery.

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3.1 Housing Reconstruction
Monitoring housing reconstruction has been the most widely used measure ofrecovery. Physical reconstruction of infrastructure and housing appear to be mostprominent because they are seen as the “key to revitalizing communities
following major disasters” (Zhang & Peacock 2009), and provide a physicalmeasure of permanent settlement population. Bolin and Stanford (1991) discuss
recovery in terms of housing recovery arguing that that economic recovery andhousing recovery are the precondition for psycho-social recovery of the victims.
Similar discussion is also carried out by Peacock et al. (2007). Thus the level of
housing restoration in a neighborhood has been directly related to the level and/or
quality of recovery in many studies. In many cases, authorities also equate thereconstruction of housing with the end of population outflow from the region, andthus positive recovery from then on. Remote sensing is a frequently used method
to observe this recovery process by the means of infrastructure and housing
reconstruction (Vinci et al. 2011).
3.2 Domestic Assests Index
Bates and Peacock (2008: 3) carry out a cross-cultural, cross-disaster impact
measure which “utilizes a conceptualization of living conditions and theirrelationship to household functioning.” The basic idea revolves around measuring
household recovery through observing the recovery of functionality necessary to
carry out a household’s routine activities. This is different from recovery
measured in terms of physical reconstruction of houses at a community scale,because it considers recovery at a more micro level scale. It focuses on “domestic
assets” (capital equipment used to perform normal household functions –i.e. stove,tables, light, etc.) acquired by a household over time and the need to reaccumulate
those in the event of a disaster. It further considers how the introduction of
housing recovery programs changes the processes through which thereaccumulation occurs and how this might affect the overall recovery process.
This methodology allows for a novel way to measure recovery cross-culturally(without being hindered by the national development status i.e. allowing
comparisons between a developing and a developed country).
3.3 Social CapitalThough Aldrich (2012)’s study is not directly related to measuring the quality ofrecovery, it measures the pace of post-disaster recovery in terms of social capital.
He studies four different disasters which vary across time and scale: Tokyo
Earthquake 1923; Kobe Earthquake 1995; Indian Ocean Tsunami 2004; andHurricane Katrina 2005 to show that “high levels of social capital –more thansuch commonly referenced factors as socioeconomic conditions, population
density, amount of damage or aid –serve as the core engine of recovery” (Aldrich
2012: 15). For measuring these recoveries, various data sets used include voter
turnout rates, participation in political activities, involvement in communal
festivals, connections to extralocal organizations and such.

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While the above have highlighted the existing methods for evaluating recovery,
they may not be the best method for evaluating the quality of recovery. For
example, in the case of housing reconstruction, many problems may continue topersist within the social fabric which may not be easily visible as discussed by
Wisner (2004) and Pais (2008). Moreover, for the case of Great East Japan
Earthquake recovery, Nakabayashi (2012) states that the first aim of recovery inthe current era of depopulation should be to restore the “human-ware” (referringto the restoration of jobs and means of livelihood), while the reconstruction of theurban spaces, urban facilities and houses, or in other words the “hard-ware” aspect,should be last.
The approach of measuring Domestic Assests Index is a useful one. However, thisis limited to measuring the recovery on the household scale. While one is likely torelate this to the overall recovery of the region, this may not be ideal. There areother layers of recovery involved such as the recoveries of the organizations,social networks, psychological rehabilitation, etc., which may not be adequately
addressed in this method.
Similarly, the application of social capital for measuring recovery pace may not
be so easy in a case like New Zealand where aftershocks are still continuing andtherefore slowing down the pace of recovery considerably (Wilson 2012). Morein-depth consideration of interactions among the different levels of social entities
and how social capital copes with reoccurring disasters in a short period of time
may be necessary.
4. MYTHS ANDRECOVERIESREALITIESOFEXECUTING

SUCCESSFUL

This section focuses on few of the general methods and practices that areconsidered to enable a good recovery. Elements such as citizen participation,
recovery speed and are emphasized in several recovery manuals and guidelines(Natural Hazards Center 2005; Department of Homeland Security & Federal
Emergency Management Agency 2005; Hyogo Prefectural Government 1995;
Canterbury Earthquake Recovery Authority 2012; The Reconstruction Design
Council in Response to the Great East Japan Earthquake 2011) but how well are
they implemented? It aims to disentangle the mythical ideologies from therealities of recovery by discussing implementation difficulties and questioning
orthodox ideas.
4.1 Citizen Participation = Successful Recovery
Citizen participation is no doubt important when it comes to recovery, andaccordingly, almost all recovery manuals worldwide have incorporated ‘public
involvement’ in their design for a successful recovery (Natural Hazards Center
2005; Department of Homeland Security & Federal Emergency Management
Agency 2005; Hyogo Prefectural Government 1995; Canterbury Earthquake
Recovery Authority 2012; The Reconstruction Design Council in Response to theGreat East Japan Earthquake 2011). “Bottom-up” community based plans are602

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hailed as successful representations of recovery, while “top-down” approaches arehighly criticized. These are evident in the recovery stories of Kobe after the Great
Hanshin Earthquake and New Orleans after Hurricane Katrina. For example,
Kondo (2008) and Edgington (2010) note that the initial selection of targeted
development areas in Kobe (the twenty-four Intensive Restoration Zones or jūtenfukkō chiiki) within a two month period after the earthquake, met with intense
resistance from the citizens due to its non-participatory nature. This led to thedevelopment of the “two stage planning process” where local governments would
set the basic urban structure and local communities would be involved in theneighborhood-level rebuilding and planning (Kondo 2008). Likewise, the New
Orleans early planning initiatives like the ‘Bring New Orleans Back’ plan
(autumn 2005 – spring 2006) also met with widespread criticisms for notincluding participatory procedures, necessitating the formulation of newparticipatory plans such as the ‘Lambert Plan’ (summer 2006) and ‘Unified New
Orleans Planning’ (autumn 2006 – spring 2007) (Barrios 2011).
Although the necessity of citizen participation is agreed upon by all researchers,
its successful implementation remains an overwhelming task. How to adequately
involve citizens? How frequently and to what extent? These are issues that needfurther deliberation. For example, Maki (2006, cited in Kondo 2008), observes
that in the case of the Great Hanshin-Awaji Earthquake recovery “community
participation in Kobe was limited to local level rebuilding planning, and did notencompass a citywide planning vision and goals for recovery” –indicating that
local level community involvement may not be sufficient. In regards to thefrequency of citizen participation, Kato et al. (2013) note that in the case of theGreat East Japan Earthquake recovery, due to the deadlines set forth by the central
government and the local municipalities’ obligations to meet these deadlines, thepublic participation and consensus building has become limited. A similar casecaused due to the “tension between simultaneous desires for speed and fordeliberation” is also observed in recovery planning of New Orleans (Olshansky2008). Moreover, as observed by Kondo (2008) and Barrios (2011), more thanoften, “citizen participation” just remains a term on recovery manuals while therigid application of professional planners’ knowledge that is without considerationof the cultural, political and historical particularity, prevails –thus “threatening theenvironmental sustainability and creates conditions of social marginalization”.
The above shows a greater dilemma in the context of how to facilitate proper
citizen participation. Clearer guidelines regarding the extent of citizen
involvement and further assessment in regards to what is adequate and what is not
is needed. And additionally, the co-relations between the time required for citizenparticipation and its effect on the pace of overall recovery needs to be thought
about. Perhaps a “total-management” system as suggested by Kato et al. (2013)need to be put in place.
4.2 Fast is Good?
In general, there exists a strong image of fast recovery being equated to successful
recovery. The Japanese recovery system tends to be especially focused on thisissue. For example, Hayashi (2007) notes that the infrastructure of Kobe was

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Vietnamrestored in two years while the economic and social recovery continued to beunderway 13 years later. Likewise, China’s rapid recovery from the large-scale
damage of the Sichuan Earthquake was completed in two and a half years
astonishing the whole world (Kato et al. 2013). Accordingly, the slow recovery of
New Orleans on the other hand, encountered severe criticisms by the public(Aldrich 2012; Barrios 2011; Olshansky 2008). The ongoing recovery from theGreat East Japan Earthquake also puts emphasis on how to achieve a fast recovery(with the official recovery duration set to five years).
However, in recent times there have been some debate regarding whether a fast
recovery is really ideal (Kato et al. 2013). For instance, Olshansky (2008) notes
how haste can create chaos and problems: decisions often occur at a faster pacethan people can absorb; planning processes may proceed even in the face of
discord; time for citizen participation may be limited (noted above as well); andmistakes in planning efforts are likely to occur. In New Zealand, the ongoingaftershocks have forced authorities to realize the dangers of a recovery proceedingin haste. The Canterbury Earthquake Recovery Authority declares the following
in their Recovery Strategy manual:“Recovery activities need to be sequenced carefully to avoid bottlenecks
and minimise frustrations. Although a fast recovery is desirable, going
too fast can create further problems. It creates competition for resources
between projects, drives up costs and creates pressure on existing
services and facilities. It may also not produce the best outcomes in thelong term. As the aftershocks are continuing, time is needed for the land
to settle down or be remediated. It is important to obtain the rightinformation, including scientific data, and take a considered approach toplanning and developing robust solutions before implementing them.”(CERA 2012)
Citing the cases of New Orleans and Canterbury recoveries, Kato et al. (2013)
also suggest that perhaps recovery does not necessarily have to be ‘fast’ indeveloped countries, but rather it is necessary to have a clear identification of theshort-term and long-term goals.
4.3 Resilient Recovery, an unachievable aim?
‘Resilience’ is the buzzword of today, at least in the field of disaster research. It
too, like recovery, is an ambiguous concept with multiple definitions given bydifferent researchers. Guo (2012) lists the chronology of the term’s use andincorporation into urban planning (presented in brief here): stemming from thefield of ecological sciences, the term originally referred to the “time required foran ecosystem to return to an equilibrium or steady-state following a perturbation”(Holling 1973, cited in Guo 2012), which was modified in the context of disasters
as the “capacity to adapt to stress from hazards and the ability to recovery quickly
from their impacts” (Timmerman 1981, cited in Guo 2012). The term was further
broadened by Pelling (2003, cited in Guo 2012) as the "capacity to adjust to
threats and mitigate or avoid harm" –which also accommodated the need toconsider and prepare against future potential disasters. An all-inclusive definition
provided by Comfort et al. (2010) provides a clearer picture:604

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ICUS Report 73“Resilience is the capacity of a social system (e.g., an organization, city,or society) to proactively adapt to and recover from disturbances that areperceived within the system to fall outside the range of normal andexpected disturbances.”
While defining a resilient system is one thing, recognizing one is an even bigger
challenge as noted by Comfort et al. (2010). In terms of recovery, this requires theconsideration of many factors, especially the state of return that resilience would
need to accomplish as mentioned by (Comfort et al. 2010: 8). Although disaster
research in recent years have put much emphasis on the resilience factor inrecovery and highlighted the need to rebuild to a better standard than the preimpact level not only in terms of infrastructure, but also through social means, thepolicy implementation of this remains to be seen. For example, Edgington (2010)
notes that “until the Kobe catastrophe there had been a notable lack of interest ineither personal recovery or the long-term revival of stricken urban areas after adisaster.” Though, after the Kobe earthquake, there have been considerable debate
among scholars regarding the insufficiencies of a system which only aims forrestoration and physical infrastructure improvement (Ota et al. 2010; Aota et al.
2010), Kato et al. (2013) note that in the current Japanese Disaster
Countermeasures Basic Act, still the term fukko (referring to “longer term
recovery”) is only used only once and even then it is used in conjunction with themore frequently used fukkyu (referring to “recovery to original state”). One reasonof such lack of implementation may be due to the fact because restoration or
rehabilitation enables the definition of a clear and measurable goal, while
recovery that emphasizes “improvement of the previous state” is more ambiguous
as well as being controversial (Ota et al. 2010).
Perhaps the same reason can be applied to the field of disaster research. The scopefor increasing resilience (or improvement) is unlimited; there will always besomething more that can be done. Thus constructing an evaluative criteria forrecovery is difficult. In addition, recovery quality comparisons are also difficult tomake because the achievable level of improvement may vary across regions orcountries due to their economic situation, political climate, cultural acceptability,
and other various issues. Furthermore, validating resilience is another difficult
task: it would be easy if the disaster occurred routinely; the capability
comparisons in dealing with the disaster could be easily studied. However, apartfrom the routinely occurring floods, disasters rarely occur at the same place withthe same criteria. Thus, measuring the quality of improvement remains
problematic and the policy aims of long-term recoveries end up being vague atbest and non-existent at worst.
5. PITFALLS OF ASSESSING RECOVERYThis section will focus on the six points raised by Quarantelli (1999) as essential
in assessing recovery and discuss what existing methods there are for evaluating
successes or failures in recovery and whether these methods address the issues
mentioned here. In brief, these are: 1) Goals of recovery; 2) Levels of recovery; 3)Size of the recovering unit; 4) Perspective on recovery; 5) Recovery from

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1) In regards to the goals of recovery, unclear goals can invite
miscommunication between those that are assisted and those that are assisting.
This is especially evident in the consideration of what the end product ofrecovery is (i.e. the state of return mentioned in the previous section).
Moreover, if a better standard than the pre-impact level is the goal, then how
to measure the improvement is also a necessary consideration.
2) The levels of recovery refers to the fact that “the [recovery] process might notproceed at the same rate or in the same way at different levels of the social
units involved” and thus any assessment of recovery has to specify what social
level unit is being evaluated Quarantelli (1999). Furthermore, considerable
research is still required to clarify the relationships between individuals,
households, organizations, and community.
3) In extension to the above point, “the larger the social unit involved, the more
likely there will be postimpact recovery” Quarantelli (1999). This refers to thefact that on a bigger scale considering overall community recovery, the (lackof) individual recoveries tend to appear insignificant, implying that smaller
units have more recovery problems which can go unaddressed. Thus, it isnecessary to recognize that the assessment of recovery will be affected by thesize of the recovering social unit considered, with the larger ones more likely
to recovery well.
4) Success or failure of recovery is also a matter that depends on the viewpoint of
the actors involved (municipality, national government, or individuals).
Quarantelli (1999) emphasizes that this may be dependent on priorexperiences; and a higher level organization such as the government, which
may have to deal with several disasters, would have a more realistic rather
than idealistic conceptions of recovery.
5) There are secondary or “ripple effects” of a disaster which may tend to go
unaddressed (for examples and details see Quarantelli 1999). Thus inassessing recovery it is necessary to take into account whether or not only
direct effects but the wider ranging indirect consequences of the disaster havebeen dealt with in the recovery process.
6) It is necessary to understand that disasters are different to catastrophes. This
important in the observation is that: community and regional level disasterthere is typically a convergence of assistance from nearby community(Quarantelli, 1999). Yet the more a disaster encompasses nearby
geographically contiguous areas, the less likely will those localities
themselves impacted, be able to help in emergency relief or recovery activities.
Thus, the larger the disaster, not only is there more likely to be greater shortand long run needs, but there is less likely to be available certain kinds ofnearby assistance that would be present in smaller type disasters. Thus, there

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is need for different kinds of planning and managing for catastrophes
compared with disasters.
6. CONCLUSION
This literature review has provided an overall survey in regards to the ongoingdebate about the concept of recovery. Along with the multiple definitions of theterm, some existing measures for assessment have been identified including the
housing recovery measurement approach, domestic assets index and social capital,
and their applicability discussed. Furthermore, by questioning the conventionallyestablished views of what an ideal recovery consists of, the paper has highlighted
the need to reconsider the means to address and assess recovery. And finally, it
has highlighted the points raised by Quarantelli (1999) which can serve as a
guideline for structuring recovery assessment studies. It is hoped that muchneeded further discussions will focus on these aspects and drive the developmentof future recovery assessment methods.
REFERENCES
Aota, R., Tsukui, S.,Yamasaki, E., Yamanaka, S. and Yamamoto, S. Special
Feature: On the Draft of the Disaster Recovery and Rehabilitation Basic Act.
Studies in Disaster Recovery and Revitalization. No.2, pp. 1-115, 2010 (inJapanese),http://ci.nii.ac.jp/naid/40017216647/en/ [accessed May 1, 2013]
Aldrich, D. P. 2012. Building resilience: social capital in post-disaster recovery.
University of Chicago Press.
Barrios, R. 2011. Post-Katrina Neighbourhood Recovery Planning, inDowty, Rachel A., and Barbara L. Allen, eds., Dynamics of Disaster: Lessons on
Risk, Response and Recovery. EarthScan: 97-114.
Bates, F. L., & Peacock, W. G. 2008. Living conditions, disasters anddevelopment: An approach to cross-cultural comparisons. University of Georgia
Press.
Bolin, R., & Stanford, L. 1991. Shelter, housing and recovery: a comparison of
US disasters. Disasters, 15(1), 24-34.
Canterbury Earthquake Recovery Authority. 2012. Recovery Strategy for Greater
Christchurch Mahere Haumanutanga o Waitaha. Christchurch: Canterbury
Earthquake Recovery Authority.
Comfort, L. K. (Ed.). 2010. Designing resilience. University of Pittsburgh Press.
Department of Homeland Security & Federal emergency management Agency.
2005. Long-term recovery planning process: A self-help guide. Washington, D.C.
The Federal Emergency Management Agency.
Edgington, D. W. 2010. Reconstructing Kobe: The Geography of Crisis andOpportunity. UBC Press.
Guo, Y. 2012. Urban resilience in post-disaster reconstruction: Towards a resilient
development in Sichuan, China. International Journal of Disaster Risk Science,
Vol.3, No.1, pp. 45-55, 2012, http://link.springer.com/article/10.1007%2Fs13753012-0006-2 [accessed May 1, 2013]
Hayashi, H. Long-term Recovery from Recent Disasters in Japan and the United

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VietnamStates. Journal of Disaster Research Vol.2, No.6. 413-418.
Hyogo Prefectural Government 1995. Hashin-Awaji Earthquake Recovery Plan
https://web.pref.hyogo.lg.jp/wd33/wd33_000000043.html [accessed on August
2013]
Kato, T., Bhattacharya, Y. Sugata, H. Otagiri, R. 2013. The Six Principles of
Recovery: A Guideline for Preparing for Future Disaster Recoveries. Journal ofDisaster Research Vol.8, No.sp. 737-745.
Kondo, T. 2008. Planning for Post-disaster Recovery in New Orleans after
Hurricane Katrina. International Symposium on City Planning, Tokyo. 2008.
Nakabayashi, I. 2012. How to Optimize the Urban Recovery After Earthquake
Disaster –Preparedness for Recovery from the Next Tokyo Earthquake- Journal ofDisaster Research Vol.7 No.2. 227-238.
Natural Hazards Center. 2005. Holistic Disaster Recovery: Ideas for Building
Sustainability After a natural Disaster. Boulder, Colorado.
Neal, D. M. 1997. Reconsidering the phases of disasters. International Journal ofMass Emergencies and Disasters, 15(2), 239-264.
Olshansky, R. B., Johnson, L. A., Horne, J., & Nee, B. 2008. Longer view:
Planning for the rebuilding of New Orleans. Journal of the American Planning
Association, 74(3), 273-287.
Ota, T., Johnson,L., Maki, N. and Hayashi, H. Planning Process of Long-term
Disaster Recovery Plan – a comparative study of planning process with Kobe and
New Orleans. Proceedings of Institute of Social Safety Science, No.13, pp.335345, 2010 (in Japanese).
Pais, J. F. 2008. Places as Recovery Machines: Vulnerability and Neighbourhood
Change After Major Hurricanes. Social Forces, Vol.86.No.4., June 2008.
Peacock, W. G., Dash, N., & Zhang, Y. (2007). Sheltering and Housing Recovery
Following Disaster*. In Handbook of disaster research (pp. 258-274). Springer
New York.
Quarantelli, E. L. 1999. The disaster recovery process: What we know and do notknow from research. Preliminary Paper. University of Delaware Disaster
Research Center.
The Reconstruction Design Council in Response to the Great East Japan
Earthquake 2011. Towards Reconstruction “Hope Beyond the Disaster” (Reportto the Prime Minister).
Vicini, A., Bevington, J., Davidson, R., & Hill, A. 2011. Post-disaster Evaluationof Community-based Housing Recovery from Aerial Imagery. Ninth International
Workshop on Remote Sensing for Disaster Response, Stanford, CA. 15-16
September 201.
Wilson, G.A. 2012. Community resilience, social memory and the post-2010
Christchurch (New Zealand) earthquakes. Area. Vol. 45 No. 2, pp. 207-215.
Royal Geographical Society (with the Institute of British Geographers).
Wisner, B. (Ed.). 2004. At risk: natural hazards, people's vulnerability anddisasters. Psychology Press.
Zhang, Y., & Peacock, W. G. 2009. Planning for housing recovery? Lessons
learned from Hurricane Andrew. Journal of the American Planning
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Study on earthquake early warnings
provided to public/advanced users
at the 2011 off the Pacific coastof Tohoku Earthquake
Ayaka NISHIGUCHI1 and Miho OHARA2
1

Master student, Department of Civil Engineering, The University of Tokyo,
a-nishi@iis.u-tokyo.ac.jp
2
Associate Professor, International Center for Urban Safety Engineering (ICUS),
Institute of Industrial Science, The University of Tokyo, Japan
ABSTRACTJapan has Earthquake Early Warning (EEW) system that provides prompt
warnings before strong tremors arrive at an earthquake. EEWs include two types
of warning; the one is the alerts for the general public receiving by TV or radio,
cell phones etc., the other is the alerts for advanced users receiving by special
receiving devices. The EEWs have a possibility to reduce physical and human loss
due to a coming earthquake. EEW for advanced users includes more detailed
information such as expected intensity or lead-time before the strong tremors
although it needs a special receiving device. It can be more effective warning to
reduce earthquake damage especially in the densely-populated or industrial area
compared with the warnings for public users.
Japan experienced the 2011 off the Pacific coast of Tohoku Earthquake on March
11, 2011. At this earthquake, EEW was provided to the general public in the partof the shaken area. However, the areas where EEW for advanced users wasprovided are not clearly understood because the reception and use of the warning
depends on the expected seismic intensity at the receiving location. Therefore, thisresearch aims to understand the situation of EEW issuance both for the public
and advanced users at the Tohoku Earthquake. The issuance times of the both
warnings were plotted on the observed seismic wave data in several cities in theeastern Japan. Considering the population and industrial activity in these cities,
the effects for reducing physical and human loss by the issuance of the both
warnings were discussed.
Keywords: Earthquake Early Warning, Disaster Reduction, the 2011 off the
Pacific coast of Tohoku Earthquake
1. INTRODUCTION
Japan has Earthquake Early Warning (EEW) system that provides prompt
warnings before strong tremors arrive at an earthquake. EEWs include two types
of warning; the one is the alerts for the general public receiving by TV or radio,609

October
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Vietnamcell phones etc., the other is the alerts for advanced users receiving by special
receiving devices. EEW for the general public started since October 1, 2007 and it
is provided especially to the regions with predicted intensity of 4 or more when
predicted intensity of 5 lower or more is anticipated. On the other hand, EEW foradvanced users includes more detailed information such as expected intensity or
lead-time before the strong tremors although it needs special receiving devices. It
is issued, as a rule, when “the amplitude of the P wave or S wave is 100 gal ormore” and “the calculated magnitude is 3.5 or more or the maximum predicted
intensity is 3 or more”. It can be more effective warning to reduce physical andhuman loss due to a coming earthquake especially in the densely-populated orindustrial area, compared with the warnings for public users.
On March 11, 2011, Japan experienced “The 2011 off the Pacific coast of Tohoku
Earthquake”. It occurred in the Pacific Ocean, and its hypocenter was 38°6’12”N,
142°51’26”E at a depth of 24km. Its magnitude (Mw) was 9.0 and maximum
JMA seismic intensity was 7 (it is maximum lank of it). Figure 1 shows the
distribution of observed JMA seismic intensity, showing the wide area in theeastern Japan was attacked by the strong tremors. The earthquake and greattsunami attacked the coastal area
caused about 18,000 dead andmissing people.
At this earthquake, EEW wasprovided to the general public in thepart of the shaken area. However,
the areas where EEW for advanced
users was provided are not clearly
understood because the reception
and use of the warning depends onthe expected seismic intensity at thereceiving location. Therefore, thisresearch aims to understand thesituation of EEW issuance both forthe public and advanced users at the
Tohoku Earthquake. The issuancetimes of the both warnings wereplotted on the observed seismic
wave data in several cities in theeastern Japan. Considering the
population and industrial activity inthese cities, the effects for reducing
physical and human loss by the
Figure 1 Distribution of observed JMA
issuance of the both warnings wereseismic intensity of the Tohoku Earthquake
discussed.
2. EEW PROVIDED AT THE 2011 OFF THE PACIFIC COAST OFTOHOKU EARTHQUAKE
2.1 Mechanism of EEW
The mechanism of EEW is shown in Figure 2. The Japan Meteorological Agency(JMA) locates about 220 seismographs in Japan which are continuously

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monitoring ground motion. When an earthquake occurs, seismometers near the
epicenter detect seismic waves and the location of its hypocenter, magnitude isdetermined by the analysis of the obtained seismic wave data. As time passes,
more seismometers can observe seismic wave and the accuracy of the estimatedinformation increases. Then, the JMA repeatedly estimates every time when it
receives new data from seismometers, and updates the warning information until
the result becomes stable. Advanced users can get all the warnings from the firstto the end of the estimation. It contains the information such as time of wave
detection, the location of estimated hypocenter and epicenter, estimatedmagnitude. It is received with a special receiving device that can estimate
additional information such as expected seismic intensity and expected arrival
time of S-wave of the earthquake at the receiving location.
On the other hand, when more than two seismometers observe ground motion andthe maximum seismic intensity is expected to exceed 5 lower, the warning isregarded as the one for the general public and provided to the regions withpredicted intensity of 4 or more by TV, radio, cell phones. In this case,information such as seismic intensity and expected arrival time of S-wave is notprovided.

Figure 2 Mechanism of EEW system
2.2 EEWs provided at the 2011 off the Pacific coast of Tohoku Earthquake
EEWs issued at the 2011 off the Pacific coast of Tohoku Earthquake on March 11,2011 are shown in Table 1. EEWs for advanced users were issued 15 times intotal. The first announcement was issued at 14:46:45, after which the informationof estimated hypocenter became accurate, and final announcement was issued at
14:48:36. The estimated magnitude was changed every time although the locationof estimated hypocenter was not altered much. During the first four warnings, themagnitudes increased drastically. It is because the earlier warnings only use thelimited number of observed seismic waves during very short time. In case of the
Tohoku earthquake, the fault size was too huge to estimate the correct magnitude
Study onearly
earthquake
early
warnings
provided to public/advanced
users
Study on earthquake
warnings
provided
to public/advanced
users
at
the
2011
off
the
Pacific
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Vietnamusing the limited number of wave observations. Then, the estimated magnitude
was decided to be 8.1 finally at the 15th warnings, which caused underestimationof the magnitude compared to the real gigantic one.
The EEW provided for public users is the fourth warning that is highlighted inyellow color in table 1. Figure 3 shows the warning message actually broadcast
for the general public on TV. It addressed only five prefecture names in Tohoku
area, Miyagi, Iwate, Fukushima, Akita and Yamagata prefecture due to theunderestimation of the magnitude mentioned above, whereas many people inother areas experienced strong tremors without receiving any EEW for public
users.
Table1 : EEWs provided at the 2011 off the Pacific coast of
Tohoku Earthquake

Time of EEW Time of EQ
Issuance
Occurrence1
14:46:45
14:46:192
14:46:46
14:46:19
3
14:46:47
14:46:19
4
14:46:48
14:46:19
5
14:46:49
14:46:19
6
14:46:50
14:46:19
7
14:46:51
14:46:19
8
14:46:56
14:46:17
9
14:47:02
14:46:16
10
14:47:10
14:46:16
11
14:47:25
14:46:16
12
14:47:45
14:46:17
13
14:48:05
14:46:17
14
14:48:25
14:46:17
15
14:48:36
14:46:17

No.

latitude
38.2N
38.2N
38.2N
38.2N
38.2N
38.2N
38.2N
38.1N
38.1N
38.1N
38.1N
38.1N
38.1N
38.1N
38.1N

Expected Hypocenter
longitude
depth magnitude
142.7E
10 km
4.3
142.7E
10 km
5.9
142.7E
10 km
6.8
142.7E
10 km
7.2
142.7E
10 km
6.3
142.7E
10 km
6.6
142.7E10 km
6.6
142.9E
10 km
7.2
142.9E
10 km
7.6
142.9E
10 km
7.7
142.9E
10 km
7.7
142.9E
10 km
7.9
142.9E10 km
8.0
142.9E
10 km
8.1
142.9E
10 km
8.1

Figure 3 EEW for public users shown on TV at the Tohoku Earthquake
3. METHODOLOGYAt this earthquake, EEW was provided to the general public in the part of the
shaken area as shown in figure 3. However, the areas where EEW for advanced
users was provided are not clearly understood because the reception and use of the612

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warning depends on the expected seismic intensity at the receiving location.
Therefore, this research aims to understand the situation of EEW issuance both forthe public and advanced users at the Tohoku Earthquake.
At first, among the prefectures hit by strong tremors, 14 prefectures in the easternJapan, Aomori, Iwate, Akita, Miyagi, Yamagata, Fukushima, Niigata, Ibaragi,
Chiba, Gunma, Tochigi, Saitama, Tokyo and Kanagawa are selected. From these
prefectures, 1 to 3 cities in each prefecture with the largest populations on thenational census (2010) are selected.
Then, the issuance times of the both warnings are plotted on the observed seismic
wave data in several cities in the eastern Japan. As the observed seismic wave
data, K-NET data in the selected cities is used. K-NET is a nation-wide strongmotion seismograph network consisting of more than 1,000 observation stations
operated by the National Research Institute for Earth Science and Disaster
Prevention (NIED) . Authors downloaded acceleration records from the website.
The estimated seismic intensity at each K-NET station is calculated using thelocation of K-NET and information of EEW shown in table 1 following thetechnical guideline of JMA. From this, the time when the estimated seismic
intensity reached to the JMA intensity 3, 4, 5 lower is obtained and plotted on the
K-NET data.
Finally, considering the population and industrial activity in these cities, the effectfor reducing physical and human loss by the issuance of the both warnings werediscussed. K-NET
4. EFFECT OF EEW ISSUANCE IN 19 CITIES
Table 2 is a list of 19 cities with large population that were selected based on thenational census (2010) . The cities with the largest population in each prefecture
and additional several cities which have more than 500,000 population wereselected and colored with red in table 2. In case of Tokyo prefecture, many cities
and wards have more than 500,000 people. So, the largest 2 cities were chosen.
Table 3 shows K-NET stations corresponded to 19 cities. Since the nearest KNET to Setagaya-ku and Nerima-ku was the same, only one station for Tokyo wasselected. In table 3, the observed instrument seismic intensity, JMA intensity andthe expected seismic intensity for each city calculated by each EEW from the firstto the fifteenth were shown. The instrument seismic intensity and JMA intensity
scale has the relationship shown in table 4. The cells of expected seismic intensity
in the table 3 were colored by this relationship.
Regarding the EEWs for public users, 5 cities in 5 prefectures (colored in red fontin table 3) exceeded the criteria and received the warnings. From this, it is shownthat there were many cities which were not received EEW for the general public
although they experienced tremors with more than 5-lower in JMA intensity scale.
At the third or fourth EEW for advanced users, the expected seismic intensities
are small with the JMA intensity 3(light blue in table 3) in almost all the cities. It
is because of the underestimation of the magnitude. However, at the later EEWs,
the expected seismic intensities increased to be around 4 and these colors changed
to be green. As mentioned before, the EEW for public uses were the fourth
warning. If an advanced user had set their criteria for receiving and using thewarnings as the intensity 4, they could not use the warnings prior to the warnings
for public use.
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Table 2 : Selected 19 cities in large population in 14 prefectures
prefecture

population [people]

more than 1,000,000 more than 500,000 more than 250,000

AOMORIIWATEAKITAMIYAGI
SendaiYAMAGATAFUKUSHIMANIIGATA
IBARAGITOCHIGIGUNMASAITAMA
Saitama
CHIBA

Aomori, Hachinohe
Morioka
Akita

NiigtaYamagata
Iwaki, Kooriyama,Fukushima
Nagaoka
Mito

Utsunomiya

TOKYO
KANAGAWA Yokohma, Kawasaki

Kawaguchi
Chiba, Funabshi
Setagaya, Nerima,
Ota, Adachi,
Edogawa, Hachioji,
Suginami, Itabashi
Sagamihara

Takasaki, Maebashi
Kawagoe,Tokorozawa, Koshigaya, Souka
Matsudo,Ichikawa,Kashiwa,Ichihara
Koto,Ktsushika,Machida,Shinagawa,Kita,
Shinjuku,Nakano,Toshima,Meguro,Fuchu,S
umida
Yokosuka,Fujisawa,Hiratsuka

Table 4 : Observed and expected seismic intensities in 19 cities
City

Expected instrumental seismic intensity at the EEW announcement
K-net Observed intensity
station JMA instrumenta 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th13th14th 15th

Aomori
AOM020 4
Akita
AKT010 4
Morioka
IWT018 5-lower
Sendai
MYG013 6-upper
Yamagata YMT010 4
Niigata
NIG010 4
Iwaki
FKS011 5-upper
Utsunomiya TCG007 5-lower
Mito
IBR006 6-lower
Takasaki
GNM013 5-lower
Saitama
SIT0105-upper
Kawaguchi SIT011 5-upper
Funabashi CHB028 5-upper
Setagaya
TKY007 5-lower&Nerima
Chiba
CHB009 5-upper
Sagamihara KNG008 4
Kawasaki KNG001 5-upper
Yokohama KNG002 5-upper

4.1 -0.22 1.40 2.34 2.78 1.81 2.12 2.12 2.67 3.14 3.26 3.26 3.51 3.64 3.77 3.77
3.9 0.21 1.83 2.77 3.22 2.24 2.56 2.56 3.09 3.56 3.68 3.68 3.93 4.06 4.20 4.20
4.8 0.41 2.03 2.98 3.42 2.44 2.76 2.76 3.29 3.76 3.88 3.88 4.14 4.28 4.42 4.42
6.3 1.04 2.66 3.62 4.08 3.08 3.40 3.40 3.92 4.41 4.53 4.53 4.80 4.94 5.09 5.09
4.2 0.40 2.02 2.97 3.42 2.44 2.76 2.76 3.29 3.77 3.89 3.89 4.15 4.29 4.43 4.43
3.9 -0.13 1.48 2.43 2.87 1.90 2.21 2.21 2.77 3.23 3.36 3.36 3.61 3.74 3.87 3.87
5.4 0.36 1.98 2.93 3.38 2.40 2.72 2.72 3.32 3.80 3.93 3.93 4.19 4.33 4.47 4.47
4.7 -0.17 1.45 2.39 2.83 1.86 2.18 2.18 2.78 2.78 3.25 3.25 3.62 3.75 3.89 3.89
5.8 -0.01 1.61 2.55 3.00 2.02 2.34 2.34 2.96 3.43 3.55 3.55 3.81 3.94 4.08 4.08
4.9 -0.75 0.87 1.81 2.25 1.28 1.59 1.59 2.20 2.66 2.78 2.78 3.03 3.16 3.29 3.29
5.1 -0.44 1.18 2.12 2.56 1.59 1.91 1.91 2.53 2.99 3.11 3.11 3.36 3.49 3.62 3.62
5.0 -0.39 1.23 2.17 2.61 1.64 1.96 1.96 2.58 3.04 3.16 3.16 3.41 3.54 3.67 3.67
5.0 -0.44 1.18 2.12 2.56 1.59 1.91 1.91 2.54 3.00 3.12 3.12 3.37 3.50 3.64 3.64
4.8 -0.46 1.05 2.10 2.54 1.57 1.88 1.88 2.51 2.97 3.09 3.09 3.34 3.47 3.60 3.60
5.1 -0.21 1.41 2.35 2.79 1.82 2.14 2.14 2.77 3.24 3.36 3.36 3.61 3.74 3.87 3.87
4.4 -0.79 0.83 1.77 2.21 1.24 1.55 1.55 2.17 2.63 2.75 2.75 3.00 3.13 3.26 3.26
5.1 -0.42 1.19 2.14 2.57 1.61 1.92 1.92 2.55 3.01 3.13 3.13 3.38 3.51 3.64 3.64
5.1 -0.24 1.37 2.31 2.75 1.79 2.10 2.10 2.73 3.19 3.31 3.31 3.56 3.69 3.82 3.82---- (1)---- (2)(a) Expected travel time of the S-wave (estimated according to JMA method)(b) Elapsed time until publishing EEW from detecting of EQ(c) The publish time of EEW (on Table1)(d) The expected time of earthquake occurrence (on Table1)

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Figure 2 Map of K-NET stations and EEW issuance on observed seismic waves
Study onearly
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early
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provided to public/advanced
users
Study on earthquake
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the
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TohokuEarthquakeat the 2011 off the Pacific coast of Tohoku Earthquake

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October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 5 : Scatter diagram of population and lead-time in large population cities
Figure 4 is a map of K-NET station and EEW issuance on JMA instrumental
observed seismic wave. Regarding the EEW for advanced seismic seismic intensity
under0.5
users, EEW issuance when they got EEWs with expected 0
1
over0.5-under1.5
seismic intensities 3,4 and 5-lower was plotted. In addition,2
over1.5-under2.5
the expected lead-time before the arrival of S-wave by the3
over2.5-under3.5
EEW was calculated by the equation 1 and also plotted on 4
over3.5-under4.5
figure 4. Here, lead-time doesn’t include the time required 5-lower over4.5-under5.0
for information transmission and calculation.
5-upper over5.0-under5.5
The red stars in figure 4 show the time when the city got 6-lower over5.5-under6.0
EEW for the public users. The red stars mean that the EEW 6-upper over6.0-under6.5
over6.5
for public users in the 5 cities was successfully provided 7
before the strong tremors. On the other hand, the cities Table 3 : Definition
without red stars could not get EEW for public users butof JMA intensity
EEW for advanced users.
Figure 5 is a scatter diagram of population and lead-time in large population cities.
It shows that many cities had more than 1 minute as the expected lead-time if they
set their criteria for receiving EEW as intensity 3. But when they got an EEW of
intensity 4 or 5-lower, some cities had minus lead-time and had been alreadysuffered from initial tremors before getting EEW. The number of advanced users
who had set the criteria for receiving EEW as intensity 3 might be small because
intensity 3 is quite low compared with the public use case. From this, it is said thatthe effect of the EEWs for advanced users at this earthquake was limited.
On the other hand, due to the underestimation of the magnitude, real S-wave took
more time for reaching at the each city than calculated by EEW. It might
fortunately give more time for people to prepare for the coming shaking.

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5. EFFECT OF EEW ISSUANCE IN INDUSTRIAL CITIESIn this chapter, the effect of EEW issuance in industrial cities was focused. Six
cities with the largest population of industrial workers were selected based onacademic census (2009). The issuance times of EEWs were calculated following
the same methodology in the previous chapter. In table 5, the observed instrument
seismic intensity, JMA intensity and the expected seismic intensity for each city
calculated by each EEW from the first to the fifteenth were shown. Figure 6 is ascatter diagram of population and lead-time in these cities.
2 cities among 6 got both EEWs for the public and advanced users, although 4
cities only got EEWs for advanced users. All the cities got the EEW of intensity 3
and most of them had more than 40 seconds as lead-time before the strong tremors.
When the expected intensity reached to intensity 5-lower, there was almost no
lead-time before the shaking. It means that the industrial companies using
advanced EEW could get lead-time for preparing for the shaking only if they had
set their criteria for receiving EEW as intensity 3 or 4.
Table 5: Observed and expected seismic intensities in 6 industrial cities
City
Hachinohe
Kitakami
Ishinomaki
Hitachi
Oota
MinatoExpected instrumental seismic intensity at the EEW announcement
K-net Observed intensity
station JMA instrumenta 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th13th14th 15th

AOM012 5-lower
IWT012 6-lower
MYG010 6-lower
IBR003 6-upper
GNM011 5-upper
TKY007 5-lower

4.9 -0.22 1.40 2.34 2.78 1.81 2.12 2.12 2.67 3.14 3.26 3.26 3.51 3.64 3.77 3.77
5.9 0.21 1.83 2.77 3.22 2.24 2.56 2.56 3.09 3.56 3.68 3.68 3.93 4.06 4.20 4.20
5.9 0.41 2.03 2.98 3.42 2.44 2.76 2.76 3.29 3.76 3.88 3.88 4.14 4.28 4.42 4.42
6.4 1.04 2.66 3.62 4.08 3.08 3.40 3.40 3.92 4.41 4.53 4.53 4.80 4.94 5.09 5.09
5.0 0.40 2.02 2.97 3.42 2.44 2.76 2.76 3.29 3.77 3.89 3.89 4.15 4.29 4.43 4.43
4.8 -0.13 1.48 2.43 2.87 1.90 2.21 2.21 2.77 3.23 3.36 3.36 3.61 3.74 3.87 3.87

Figure 6: scatter diagram of population and lead-time in industrial cities

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early
warnings
provided to public/advanced
users
Study on earthquake
warnings
provided
to public/advanced
users
at
the
2011
off
the
Pacific
coastof
TohokuEarthquakeat the 2011 off the Pacific coast of Tohoku Earthquake

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6. CONCLUSIONSThis research aimed to understand the situation of EEW issuance both for the
public and advanced users at the 2011 off the Pacific coast of Tohoku Earthquake
on March 11, 2011. The issuance times of the both warnings were plotted on theobserved seismic wave data in several cities in the eastern Japan. Considering the
population and industrial activity in these cities, the effects for reducing physicaland human loss by the issuance of the both warnings were discussed.
All the targeted cities with large populations got EEW for the advanced users,
although the number of the cities provided with the EEW for the public users waslimited. Regarding EEW for advanced users, many cities with large populations
had more than 1 minute as the expected lead-time if they set their criteria forreceiving EEW as intensity 3. But when they got an EEW of intensity 4 or 5lower, some cities had minus lead-time and had been already suffered from initial
tremors before getting EEW. From this result, it is said that some of the public or
advanced users of EEW could get much lead-time to prepare for the shaking, but
unfortunately, these populations might be limited due to the underestimation of
the magnitude of the Tohoku Earthquake in 2011.
As a future study, the effect of EEWs at the aftershocks had better be analyzed.
Now, the technologies for source estimation are being improved based on thelessons from the Tohoku earthquake. It is expected that EEW could give more
effect for reducing physical and human loss at the coming earthquakes.
ACKOWLEDGEMENT
We would like to thank Dr. Hiroshi TSURUOKA, Associate Professor of
Earthquake Research Institute for providing the records of EEW and helping withseveral estimations. We also thank NIED for permitting the use of K-NET data.
REFERENCES
Japan Meteorological Agency, http://www.jma.go.jp/jma/en/Activities/eew.html
National Research Institute for Earth Science and Disaster Prevention (NIED),
http://www.kyoshin.bosai.go.jp/
Statistics Bureau, Ministry of Internal Affairs and Communications, 2010
Population Census, 2010
Statistics Bureau, Ministry of Internal Affairs and Communications, 2009
Economic Census, 2009

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Study on victim transportation planningconsidering street blockades-Case study of expected Tokyo inland earthquake-

Fei JIANG1, Miho OHARA2
1
Master Course Student, Graduate School of Interdisciplinary Information Studies
The University of Tokyo, Japanjiangfei@iis.u-tokyo.ac.jp
2
Associate Professor, International Center for Urban Safety Engineering (ICUS),
Institute of Industrial Science, the University of Tokyo, Japan
ABSTRACTTokyo Metropolitan area has high risk of the Tokyo Inland Earthquake in the
future. In case of the earthquake, disaster base hospitals have missions toaccommodate seriously-injured victims and provide medical treatment for them.
According to the lessons from past disasters, medical treatment within 72 hours
after the disaster is essential to increase the possibility of saving the lives ofvictims. Rapid transportation of seriously-injured victims to disaster basehospitals and immediate medical treatment are very important to avoid their“Preventable Death”.
In this research, effect of street blockades to transportation of seriously-injured
victims to hospitals in case of the expected Tokyo Inland Earthquake wasanalyzed considering road network. The maximum transportable area where
victims could be transported to some hospitals by car within certain time was
identified using a software “ArcGIS Network Analyst”. After the Kobe
Earthquake in January 1995, road blockades due to the debris from collapsedbuildings caused problems on medical transportation. This research simulated theeffect of road blockades on maximum transportable area. As a result, almost all
the areas in Tokyo Prefecture were accessible to disaster base hospitals within 10
minutes by car in normal situation. However, maximum transportable area
drastically shrank when road blockades in case of disaster was considered. This
analysis identified the areas where rapid transportation to the nearest disasterbase hospitals was impossible in case of the earthquake. Increase in the numberof disaster base hospitals or dispatch of medical treatment team with portablefacilities such as DMAT (disaster medical assistance team) may be necessary inthese areas.
Keywords: Tokyo Inland Earthquake, seriously-injured victims, disaster basehospitals, transportation619

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1. INTRODUCTION
It is believed that in the Tokyo Metropolitan Area, massive trench-type
earthquakes with magnitudes of 8 or greater, such as the Great Kanto Earthquake(1923), will occur at intervals of 200-300 years. Additionally, it is presumed thatseveral Tokyo Inland Earthquakes of magnitude 7 will occur prior to a magnitude
8 earthquake, and the imminent possibility in the first half of this century has been
pointed out. Because of that, many types of Tokyo Inland Earthquakes are
assumed by the cabinet office of Japanese government and Tokyo metropolitan
government with various possible epicenters and the complicated mechanism ofoccurrence. According to the estimation of The Tokyo metropolitan government,
the number of seriously-injured victims will be about 150 thousand in theearthquake with an epicenter in the northern part of Tokyo Bay (assumed scale ofM7.3, 18p.m.). So, it is essential to provide the medical treatment within 72 hours
after the disaster to increase the possibility of saving the lives of victims due tothe lessons from past disasters. Rapid transportation of seriously-injured victims
to disaster base hospitals and immediate medical treatment are very important toavoid their “Preventable Death”.
A disaster base hospital is responsible to accommodate seriously-injured victims
whom the medical aid stations are not able to treat, based on the stations’ request(Tokyo metropolitan disaster base hospital installation management guidelines,
2003). A disaster base hospital is designated as huge hospitals with enoughseismic strength of buildings. In Tokyo metropolitan area, there are 70 disasterbase hospitals and 182 emergency hospitals, with an average number of beds of
574 and 158. Figure 1 shows the distribution of seriously-injured victims based on
the occurrence of the earthquake with an epicenter in the northern part of Tokyo
Bay (assumed scale of M7.3, 18p.m.). The darker the color is, the higher thenumber of the seriously-injured victims is. The circles with black dots are thedisaster base hospitals and the empty circles are the emergency hospitals, where
the size of the circles shows the number of beds. According to this figure, theeastern part of the Tokyo metropolitan area has more seriously-injured victims but
has fewer disaster base hospitals.

Figure 1: Distribution map of heavily-injured victims and hospitals in Tokyo

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However, as figure 2 shows, the eastern part of the Tokyo metropolitan area is themost severe part according to building collapse. The debris may cause serious
street blockades and traffic jams which could impede the speed of medical
treatment and decrease the possibility of saving the lives of victims.

Figure 2: Distribution of the total collapse of buildings(Assumption by Tokyo metropolitan government)
There are mainly two previous researches on the seriously-injured victims
transported to disaster base hospitals. Ohara (2008) estimated the number ofseriously-injured victims transported to disaster base hospitals and emergency
hospitals using an entropy model. However, the direct distance between thelocation of the injury and the hospital has been used in calculations instead of theroad network. Maruyama (2010) analyzed the level of function loss of disasterbase hospitals. Road network and decrease of the speed of transportation due tothe street blockades based on the intensity of earthquake were considered.
However, it still needs some more detailed calculations on the effect of street
blockades.
Based on the background and previous researches, this paper aims to consider theroad network and the effects of street blockades on transportation to identify theareas where rapid transportation to the nearest disaster base hospitals are
impossible in case of the expected Tokyo Inland Earthquake. This kind ofanalysis would become a basis to provide a plan for increasing number of disasterbase hospitals by strengthening existing emergency hospitals or the dispatch of
medical treatment teams with portable facilities such as DMAT (disaster medical
assistance team) in these areas.
2. METHDOLOGY
To identify the areas where rapid transportation to the nearest disaster basehospitals is impossible, “ArcGIS Network Analyst” is a useful tool. It can be used
to identify the maximum transportable area up to which victims could betransported to a specific hospital by car or on foot within a certain time. This

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October
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October
2013, Hanoi,
Vietnamsection describes the outline of the methodology to analyze the traffic situation
both in normal and disaster situations using “ArcGIS Network Analyst”.
2.1 Method of traffic simulation in normal situation
First, a hospital database was made based on the list of disaster base hospitals inTokyo metropolitan area. Next, the map, hospitals and road network (Table 1) of
Tokyo metropolitan area were plotted on GIS. The maximum transportable areas
have been identified for time distance of 5 and 10 minutes traveled by car, using“ArcGIS Network Analyst”. Figure 3 and 4 show the maximum transportableareas within 5 minutes and 10 minutes, respectively. According to the Fire andDisaster Management Agency of Japan, the average time from the ambulance callto reach was 10.2 minutes (2012). Figure 4 shows the result that almost all thearea in Tokyo Prefecture is accessible to disaster base hospitals within 10 minutes
by car after an ambulance call.

Table 1: Velocity table of roads in Tokyo metropolitan area

Figure 3: The maximum transportable areasof disaster base hospitals in 5 minutes

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Figure 4: The maximum transportable areasof disaster base hospitals in 10 minutes
2.2 Method of traffic simulation in disaster situation
The Method of traffic simulation in disaster situation is almost the same as that innormal situation except for the road network changes. Here, the effect of street
blockades on transportation was considered. Figure 5 shows the flow of themethod of traffic simulation in disaster situation.

Figure 5: Flow of the method of traffic simulation in disaster situation
At first, using the 250 mesh data of expected partial damage rate and the totalcollapse rate of buildings in case of the earthquake with an epicenter in the

Study on victim transportation planning considering street blockades
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October
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October
2013, Hanoi,
Vietnamnorthern part of Tokyo Bay, building damage rates was calculated by the equation
below:
Building Damage Rate = Total Collapse Rate + 1/2 Partial Damage Rate -----Eq.1
Next, the expected blockade rates of the links were calculated using building
damage rate. Ieda (1997) surveyed the relationship between building damage andblockade rates in the affected district in Kobe City after the 1995 Kobe
Earthquake. According to these survey results, equations based on the widths ofroads were proposed by the Cabinet Office of Japanese Government forcalculating blockade rates of links in the damage estimation of the Tokyo Inland
Earthquake. In this research, the calculation using the equation based on the worst
situation by Ieda’s survey was defined as case 1, the equation used in the damage
estimation of the Cabinet office as case 2 and the equation based on the best
situation by Ieda’s survey as case 3. In figure 6, case 1, 2 and 3 according to thewidths of the roads are shown in red, green and orange lines, respectively.

Figure 6: The relationship between building damage rate and blockade rate of link
Then, the blockade rates of the meshes were calculated by the blockade rates ofthe links using the equation below:

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Eq.2

Case 1Case 2

Case 3Figure7: Distribution of blockade rates of meshes of case 1, case 2 and case 3
Based on the result of the blockade rates of the meshes of case 1, 2 and 3 shownin figure 7, restriction polygon barriers or scaled cost polygon barriers were added
to the meshes. Figure 8 and 9 show examples of restriction polygon barrier andscaled cost polygon barrier, respectively. Barriers are feature classes in network
analysis layers that restrict or alter impedances of the underlying edges andjunctions of the associated network dataset. There are two types of polygon
barriers; one type is restriction polygon barrier that prohibits travel anywhere thepolygon intersects the network, and the other type is scaled cost polygon barrierthat doesn't restrict travel on the edges and junctions it covers; rather, it scales thecost of traversing the covered edges and junctions by a factor you specify. For
example, a factor of 2 would mean it is expected to take twice as long as normal.

(Example)
Figure 8: Restriction polygon barrier(Example)
Figure 9: Scaled cost polygon barrier

According to Hagita (2009), in the case of Hanshin-Awaji Earthquake, therunning speed of Route 2 of the Kobe city fell down from 25 km/h of rush hours
in normal situation to less than 3km/h at the day of the occurrence. Because therunning speed fell down to almost 1/10 of the normal situation, a factor of 10 was
adapted as scaled cost polygon barriers as shown in figure 10. Furthermore,according to Ieda’s survey (1997), almost all the road users gave up using theStudy on victim transportation planning considering street blockades
Studyon victim
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Vietnamblockade links or areas which had been blocked with 20% or more. Based on this,restriction polygon barriers were added to the links with 20% or more blockades
as shown in figure 10. According to the result of blockade rates of the meshes ofcase 1, 2 and 3, restriction polygon barriers were added in case 1.
Lastly, by operating the “ArcGIS Network Analyst” within 10 minutes based on
the changes of the roads, the maximum transportable areas in disaster situation
were identified.

Figure 10: Relationship between cost and blockade rate of mesh
3. SIMULATION RESULTS
The result of inaccessible meshes of case 1 (Figure 11) shows that most of theinaccessible meshes were in the eastern part of Tokyo, which led to seveninaccessible hospitals and much shrank of maximum transportable areas (Figure12) to the nearest hospitals compared with case 2 and case 3. Furthermore,compared with the normal situation, the maximum transportable areas also shrankseriously when road block in case disaster was considered. However, themaximum transportable areas could be expanded when transportation to disasterbase hospitals and emergency hospitals were both considered as shown in figure
13.

Figure11: Inaccessible meshes of case 1

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Figure12: Transportable areas of disaster base hospitals

Figure13: Transportable areas of disaster base hospitals and emergency hospitals
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4. CONCLUSION
This study simulated the effect of street blockades on the transportation ofseriously-injured victims to hospitals using “ArcGIS Network Analyst” in case of
the expected Tokyo Inland Earthquake. The simulation results showed that almost
all the areas in Tokyo Prefecture were accessible to disaster base hospitals within
10 minutes by car in normal situation. However, maximum transportable area
drastically shrank when road block in case of disaster was considered. This
analysis identified that the rapid transportation of the eastern part of Tokyo
metropolitan area to the nearest disaster base hospitals would be impossible incase of the earthquake.
According to this result, a series of countermeasures such as upgrading existing
emergency hospitals as disaster base hospitals, increasing in the number ofdisaster base hospitals by new construction, preparation for accommodating
victims rapidly in the hospitals in surrounding areas with little damage or dispatchof on-site medical treatment team with portable facilities such as DMAT (disastermedical assistance team) could be considered in those areas.
As future studies, various scenarios should be considered such as expanding the
maximum transportable areas to within 30 minutes or 1 hour or changing theparameters of the scaled cost polygon barriers, etc. Additionally, transportation to
the hospitals on foot should also be considered in the next steps.
REFERENCES
Tokyo Metropolitan Government, 2012. Damage Estimation of Tokyo Inland
Earthquake.
Cabinet Office, Government of Japan, 2013. Damage Estimation of Nankai
Through Earthquake
Ohara, M., Meguro, K.,2008. Estimation of the number of heavily injured victims
transported to hospitals in case of expected Tokyo Inland Earthquake. Industrial
Research vol. 60, No. 6, pp. 33-38.
Sho, L., Maruyama, Y., 2010. Analysis of wide area road network of disaster basehospitals in case of expected Tokyo Inland Earthquake, proceedings ofundergraduate’s thesis, Chiba University.
ArcGIS help 10.0: Restriction polygon barrier and scaled cost polygon barrier
http://resources.arcgis.com/en/help/main/10.1/index.html#//004700000056000000
Ieda, H., Kaminishi, S., Inomata, I., Suzuki, I., 1997. Street Blockades in Hanshin
Earthquake'95 and Its Influence on Disaster Relief Activities. Doboku Gakkai
No.576/ IV-37, 69-82.
Kagita, K., Yamashiro, T., Hongo, K., 2009. Operating simulation of police
rescue corps on the next Tokyo Metropolitan Earthquake. National ResearchInstitute of Police Science Report 60 (1.2), pp. 30-36.

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Solutions for a higher living quality for people
in Hanoi’s Old Quarter
1,2

Thi Hoai An LE1 and Anh Quan PHUNG2
Lecturers, Faculty of Construction Economics and Management,
National University of Civil Engineering, Vietnam
hoaian102@gmail.com

ABSTRACT
Locating in the centre of Hanoi, the Old Quarter (OQ) has been establishedthousands years ago and become one of the most significant heritages of this city.
The paper first presents a set of indicators developed to be used in a survey formeasuring aspects of living quality of Hanoi’s Old Quarter inhabitants and theirdwelling expectations. The result shows that people living in the Old Quarter have
faced with so many problems that impact on the quality of their life such as
unsecured life, environmental pollutions, cramped shelters, and infrastructure
downgraded. It can be seen the main cause of this serious situation is overloaded
population, so the key solution for the OQ is the decrease in population density.
Therefore, 3 main groups of the inhabitants are indentified: (1) People compelled tomove out; (2) Inhabitants want to change dwelling location; and (3) Residents keep
staying in the OQ. Based on the three categories, the paper puts forward somerecommendations for the government to support inhabitants in each group to
improve their quality of lives in the Old Quarter. Moreover, the research notices arelationship between people’s dwelling expectation and financial benefits that theygained when running a type of business in the OQ. The Government should takethis relationship in account when considering and implementing further solutions.
Keywords: old quarter, life quality improvement, dwelling expectations, reduce
population density
1. INTRODUCTION
Hanoi’s Old Quarter (OQ) is located in the center of Hanoi. It is well-known
because of the unique architectures and significant heritages in the area. The OQ
was formed in Ly dynasty (in the 11th century) and it has become a heavily
populated and the most bustling trading area since that time.
The OQ is recognized as a preserved area because it represents many historical andcultural heritages of the capital city and becomes one of the famous features of
Hanoi’s tourism. As in an old saying: “Birds of a feather flock together”, people
living nearby in the OQ often formed specific guilds trading and/or producing thesame type of products. Thus, in the OQ, each street was addressed a name closely
related to a particular traditional trading product, e.g. “Hang Muoi” (salt market) for
the street selling salt, “Hang Manh” (curtain market) for the street selling bamboo
curtains. Currently, Hanoi’s OQ covers 100ha, including 10 wards of Hoan Kiem

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VietnamDistrict and up to 76 streets [MOC, 1995]. Over thousands years of development,
the OQ has changed significantly. The infrastructure there has been downgradedwhile the population density is very high and seems to be increasing in the future.
There are about 82.300 people per square kilometers, that it is classified in one of
the most crowded areas in the country [Statistic, 2009]. Consequently, the OQ
inhabitants are living in a lower level of living quality than people in others parts ofHanoi. Being aware of that serious problem, various agencies of the city and thenational government have been trying to find out effective methods for theenhancement of life quality in the OQ. Unluckily, there are no solutions worked
effectively so people there continues living in unfavorable conditions.
2. METHODOLOGY
The paper uses results from survey with respondents who include people living in
the OQ, civil servants in the area and selected experts to determine the failurecauses of previous living quality upgrade plans as well as to measure significant
aspects of living quality of the OQ inhabitants and classify their dwelling
expectations in the situation. A total of 52 factors were included in the questionnaire.
The interviewees are requested to answer the questions according their own
experience and feeling of life in the OQ. 57 results of the questionnaire werereceived back from plenty of age, occupation, house location, gender, and time ofliving in the OQ of interviewees. Collected data was transcribed, coded, andanalyzed using SPSS software. Moreover, authors had met some experts andplanning officer to interview for their expectations, as well as experience andcurrent situation of implementing related OQ project.
3. CURRENT LIVING QUALITY STATUS OF THE OQ INHABITANTS
According to previous researches and the survey results, there are both advantages
and disadvantages living in the OQ. Significant advantages include improvingsocial status, experiencing diversity in cultural and spiritual activities, getting more
opportunities in doing business and servicing tourists and being highly prioritized inselected government policies. Besides, narrow houses and environment pollution
can be considered as major disadvantages of living in the OQ.
3.1 Advantages- Improving social status: Because of specific history and culture, the OQ isrecognized as the most centralization area and a pole status of Hanoi city [H.H.Phe,2000]. The survey shows that the residents are very proud to be the residents of the
OQ and they feel satisfactory with convenience of living in this area. There are 87%
people live there stated that they are proud and very proud to be inhabitants of the
OQ. In detail, the distance from their houses to some important facilities likeschools, hospitals, administrative offices is short. Moreover, it is very convenient
for their daily life activities because supermarkets, restaurants, shops, andentertainment places are located inside and around the OQ. In addition, the630

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inhabitants said that living in the OQ gave them many priorities in getting jobs,
borrowing capital from banks and obtaining school admission for children.
- Diversity in cultural and spiritual activities: Because of its 1000-year history withtrading unions and villages, residents in the OQ experience a diverse environment
in terms of united community, cultural and spiritual life. Firstly, one positive
consequence of the living conditions in the quarter is that people tend to help eachother even in small matters such as shopping, cooking meals and looking after one
another’s houses and children. Sharing a living space with many other family
members, people must harmonize their individual personalities in order to live
together happily as a united community. Secondly, Hanoi People Council organizes
a lot of annual cultural and entertainment activities such as Flower festival, Firework, Mid-term festival which can enrich the spiritual life of the OQ inhabitants.
Last but not least, there are many temples in the OQ to commemorate the foundersof their trade or craft, for instance Lo Ren temple (blacksmith), Thuong temple,
Kim Ngan temple (jewelery). This, thus they feel safe in soul and make them wantto live there in long time.
- Advantages in doing business and providing tourism services: The OQ is alocation that attracts tourists, especial foreign tourists, because of its unique features,
millennial culture and history. As a result, traditional trading activities, souvenir
shops, restaurants, hotels have been developed and have created job opportunities
for people in the area. If a household has a house for rent they can earn muchmoney from the status of their location.
- Get priorities in government policies: In order to preserve the OQ as a historicalcultural heritage, on the 4th June 1999, Hanoi People’s Committee issued theTentative Regulations on Management of Construction, Preservation, andRestoration of Hanoi’s OQ. Consequently, more priorities are given to theimprovement of infrastructure in the OQ than in other areas in Hanoi. The
Regulations also state that, in the near future, the drainage and sanitary system in
the Old Quarter will be improved and rebuilt. The networks of electric wires andcommunication cables weaving above the streets in the Quarter will be replacedwith underground systems. Recently, Ministry of Construction, being supported byexperts from Toulouse city (France) has succeeded in the project of “Preservation,
Renovation and Refurbishment apart of Ta Hien street” and the similar projects will
be carried out in other streets in the OQ in the future.
3.2 Disadvantages- Cramped living in narrow house: In the past, the most popular structure for housesin the OQ was the old type of house named “tube house”. In this type of house, thestructure nevertheless was deeply influenced by life style, old handicraft industrial
production and old trading. The house was narrow in width and about tens of meters
long. Sunlight entered the structure through open yards and courts, giving the housean open feeling and healthy atmosphere. On the ground floor of each house, there
was a shop, and the back was used to produce goods and people lived there. The
inner yard, kitchen and the back garden were used by both families.

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Figure 1: Typical architect of houses in the OQ in 1800s
When the next generations were born and grew up, the situation has changed
dramatically. The number of people living in the house keeps increasing whereas
the area of the house stays limited. Although they expanded living area by using
open yards, courts and lane areas, the average area per person in the OQ is verysmall. In Hang Buom Street, there is a two-member family with a dad and a son
living in an area of about 3m2 (1.9mx1.2m) participated in the survey. According to
the data collected from the survey, the average area per person in the OQ is
12.275m2/per person while the average figure for Hanoi is 21.5 m2/person [Hanoi
People Committee, 2013].

Figure 2: Revolution of old houses

Figure 3: A typical house in the OQ in 2000s- Pollution in the living environment: Living in a small area and sharing a kitchen
and a WC makes people unsatisfactory even in personal demands. For example, inthe house No 44 at Hang Buom street, there are 3 families with up to 40 people
sharing a water closet The water closet is old and shabby so that local people feelvery inconvenient. In addition, the low graded sanitation system has bad influenceon the surrounding environment. Lanes are often small and dark. Almost all of lanesin the surveyed area are just from 0.60 to 1.0 meter in width and always ininsufficient lighting condition. Similarly, the buildings always lack natural light,
natural wild, especial houses in inner lanes. Even worse, in the rainy seasons andespecially after some terribly heavy rains, some streets, for instance Phung Hung,
Ha Trung, Dinh Liet etc.., have been flooded polluting the area and may bring highrisky diseases to the inhabitants. Furthermore, several respondents in the survey
stated that they were unhappy due to the sound pollution from tourism activities, forexample a night market at weekends in streets.

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4. PROBLEMS IN THE ENHANCEMENT OF THE LIVING QUALITY IN
THE OQ
The main cause of the problems mentioned above is the high population density in
the OQ. Since 1998, Hanoi People committee has issued plans for moving people
from the OQ to other parts of the city, and for improving living conditions.
However, these previous plans were not successful as expected because of their low
feasibility. In 9th January 2013, Hanoi issued Decision No 168/QĐ-UBND whichapproved the plan for moving people out of the OQ in order to attempt solving the
problems for the majority of people living there. According to the literature reviews,
expert judgment, and the survey result, the difficulties in moving inhabitants out
from the OQ and in improving their living quality include:- Problems related to perception change of the OQ inhabitants: For the residents, theadvantage of their dwelling location as mentioned above is meaningful. Although
they know their unsafe living status, they do not want to move out of the OQ. In thesurvey, 70.4% of the participants do not want to move out and only 1.9% of themwant, but in the near future. They do not want to move because they worry if living
conditions in the new place can be as convenient as in the OQ. People are afraid oflosing their current job and having difficulties in applying new jobs in the newlocation. Besides, they enjoy interesting culture and living a spiritual life as well aswith good neighborhoods and community relationship in the OQ.
- Problems of people who want to move houses: These people account for only
1.9% of the participants, yet most of them have financial problem. They do not haveenough money to buy a new house while it is difficult for them to sell their current
house in the OQ because of the tiny area (approximately 10m2)- Problems with the authorities’ actions: Because the OQ is a conservation area, any
minor changes must be reviewed and approved before being executed. For thedowngraded, crowded and old apartments in other areas of Hanoi, it is easy todemolish them, and then build new ones on the former ground with many more
floors. However, this solution cannot be applied here. The height of buildings in the
OQ is controlled by Hanoi Department of Planning and Architecture. Accordingly,
all buildings are required not exceeding 3 floors (not counting the mezzanine in the
1st floor), the maximum height (from the ground to the top of the roof) is prohibitedto exceed 12 meters. Moreover, as the budget for solving the problem is limited,authorities have insufficient source to implement expensive and complete solutions
such as relocation allowance, housing subsidization for all householders in the OQ.
5. SET OF INDICATORS TO MEASURE THE LIVING QUALITY OF OQRESIDENTS - RESULTS AND RELATIONS
5.1 Result of the survey
A special set of indicators was created in order to measure the current living qualityof OQ residents. The measurement of indicators was based on the 5-point likert
scale with code 1 to code 5. Code 1-5 mean strong disagree, disagree, neutral, agree

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Vietnamand strong agree, respectively. This set of indicators based on 10 types of indicatorsof “The quality of Life indicators project” that New Zealand government was
implementing in their country. There are 10 categories of indicators used toestimate the living quality of residents in Hanoi’s OQ.
Table 1: Indicators of the survey
No

Sectors1

Education2

Health caresystem3

Safety andsecurity

4a

Housing andartificial
environment

5

Traffic

6

Convenienceof service andproducts

78910Socialconnection
Civil and
Political
RightsEconomic
standard oflivingEconomicdevelopment

Indicators
Short distance from house to school, quality ofthe education system, convenience in reaching
extra education, effort of the government indeveloping education
Effort of the government in preventing
infections, distance from the house to the nearest
health care center, quality of health care system
Sense of safety, safety for children and oldpeople, frequency of accidents, criminal rates
Satisfaction of: the living (area, house structure,equipment), population density, surrounding
building, air quality, green rate, noise pollution
Satisfaction of the services: Electricity, watersupply, sewage system, garbage collection,
vehicle parking
Traffic jam, convenience, fluency, public
transportation system

Range
of
Means
3.524.2
3.583.98
3.984.73
2.073.22
3.053.8
3.0-3.58

Convenience in reaching to markets, places ofamusement, other services and products

3.264.19

Harmony with neighbors,
community activitiesin3.243.94

Strong voice to related policies, understand ofcurrent policies and plans

2.5
-3.06

Total income, total expense, comparison ofliving cost, financial trouble

1.932.84

Running business in the house, total profit
gained, difficulties in running business2.614.07

diversity- Education and health care system: The people in the OQ highly appreciate thehealth care system and preschool-primary education in this area. The median valueof the all these variables achieved level 4/5 (Good).

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ICUS Report 73- Safety and security: The inhabitants believe this is a very safe area to live. Over
three-quarters of respondents agreed and strongly agreed that the sense of security;and safety for the elderly and children in this area is good. Accidents and criminals
in this area is very low. Actually, people rarely have witnessed robbery or accident
within recent 12 months.
- Housing and artificial environment: Contrary to the position of a status pole inHanoi, the quality of housing in this area is rated in low levels. Indicators in section
4 of the table illustrate that people do not satisfy with their houses and surrounding
buildings in terms of construction quality, and especially for noise pollution, which
frequently occur day and night because of animated business activities. However,the quality of supporting services is good and meets almost demands of residents.
- Traffic in the area: Data in section 5 of table 1 demonstrates that the transportation
system of people living here is relatively favorable. This convenience was createdby the centralization of roads in this area, and great success of OQ scheme inarranging and distributing transport flows. Therefore, traffic jams have not occurred
frequently in this region.
- Convenience of services and products: The people can be very favorable for
shopping, eating, drinking and entertaining in this area. As this is a diverse area interms of commercial products and services, people can easily buy all products theyneed without going far. Moreover, the OQ also focuses a big number of restaurants,
markets and malls, small shops at acceptable prices.
- Social connection and Civil and Political Rights: With high average scores ofindicators in section 7 of the table, people in this area represent a strong link among
their neighbor community as the content of 3.1 in this paper. Besides, through thecriteria in Section 8 of the table and the results of open-answer questions in thesurvey, people living here found their voice in terms of affecting politics and policy
issue is in normal level. Besides, activity of announcement responded by local
government seems not to work effectively.
- Economic development and Economic standard of living: It is easy to see thatmajority of local people are not pleased about their income. The result of the survey
illustrated that 70.5% of asked households have total income under 700US$ permonth. However, their monthly expenditure is quite high and it is expected to be
more expensive than other regions (94.4% of respondents agreed with thisstatement). In addition, about one half of the asked households run a business in or
nearby their house in order to take commercial advantage of the location. In fact,
this is a good place to trade any kind of goods and products. Furthermore, there are
not many difficulties with the local authorities as well as the people living around.
5.2 The relationship between the living quality and dwelling expectation
By analyzing data, hypotheses testing was carried out (with 5% accepted error) tofind down the relationship of ordinal variables (indicators), the scale variables andnominal variables (which identified the decision whether or not to move out of OQ).
There are several interesting findings:

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Vietnam- There is a relationship between owning a type of business in or nearby the houseand dwelling related decision. Specifically, if residents run a business in their house,
they trend to keep staying in that house. On the contrary, when local people cannot
make profit by using their house, they rather choose to move out. The strength of
this relationship is reflected by the value of the gamma coefficient, at a rate of 0.567.
Error of this hypotheses testing is 3.8% (Lower than accepted rate of 5%).
- There are unrelated or weak relations between dwelling related decision and thesevariables in pairs: average living area per person; rated value of living quality(presented in the result table); number of years that they have been living there; andproudness to be an OQ resident.
6. SOLUTIONS OF IMPROVING LIVING QUALITY IN THE OQ
Through the investigation, it can be seen that the key solution to improve living
quality in the OQ is successes in moving people out of the OQ project. And
according analysis of the set of indicators, the research notices a relationshipbetween people’s dwelling expectation and financial benefits that they gained whenrunning a type of business in the OQ. Good quality of life should satisfy people's
desire for their own lives. Therefore, the Government should give priority to solve
business problem or occupation opportunities for people who want to move out.
6.1 Solutions for business or occupation problem
Obviously, the people are afraid of losing their current jobs and having difficulties
in applying new jobs in the new location, especially for households that run abusiness in the OQ area. Therefore, this problem must be considered in solutions.
There are several ways to solve this: Initially, the government is supposed to give
good business conditions for people after resettlement. In detail, 1st floor ofapartment blocks in resettlement area need to be designed as series of shops to help
the households continue their current business. Secondly, the authority could open
skills training, vocation classes in accordance with the industries in nearby districts
for resettlement people to help them having more work opportunities in the new
relocated area. Besides, opening more factors for city establishment (like industry
area, service and entertainment centre, and education system) must be implemented
simultaneously to create employment. Moreover, the government should takesources of competitive advantage in account when researching and making city
plans. Thirdly, the public transport system from new resettlement area to the center
should be improved in terms of capacity, and service quality.
6.2 Classifying groups of inhabitants’ expectations“Divide and conquer” is always a good strategy. In order to resettle the inhabitantsin the OQ, a realistic and feasible classification must be identified. Under particularconditions of the OQ, there are three groups of the residents:- The 1st group includes the people living in the public or historical places likemonument, campus of the school, state offices. Once their appearance in these636

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places makes bad impact to public activity, they are forced to change dwelling assoon as possible. It is very easy to define household in that group by investigating
public places in the area. For this group, they should be announced strictly about
resettlement requirement. The priority policy will depend on their collaboration
with the government.
- The 2nd group is people living in private area but willing to move out. The 2ndgroup can be identified by a simple survey of the local government. Preferential
policies for this group could be priority of buying new house in the newresettlement areas, especially for households that currently living in small house(less than 5m2 per person). Other subsidized policies like relocating support, loaned
with low interest rate from state banks will be considered.
- The 3rd group is largest. They are residents that do not want to change dwelling.
For these households, if their residential area is so small, they should have priority
to buy the area of the households in the 2nd group surrounding their houses.
Authorities will play a mediating role to ensure purchase price is reasonable andreflected the true value of that area. The households must sign one commitment, in
collaboration with the government in improving the living environment there likereconstructing toilets, and alleys.
6.3. Appropriated design solutions and attractive life in the resettlement.
Hanoi People's Committee is currently investing in Viet Hung urban area, which islocated far from 6km to the city center to relocate people. This project is giving
priority registration for people in 1st and 2nd groups. This urban area need to meet
three requirements of architecture, community connection and living facilities.
Firstly, the architecture solution in new settlements should retain the specificcharacteristic activities of the ancient OQ like traditional trade, food, andcommunity. Architecture of buildings needs to be flexible with various apartments’area. It is required to be suitable with the financial condition of each household. Incase of paying by installments, payment schedule need to be long enough and beflexible to help people in buying new houses. Secondly, community events, which
is familiar with normal life in OQ could be organized to attract people living in new
settlement are. For example, night markets, flea markets and other exciting activity
like farmers market. Lastly, transportation system, infrastructure, and other facilities
in resettlement are expected to meet requirement of the former residents;
kindergartens, schools, and health care centers will be built in the resettlement area.
6.4. Solutions to improve the quality of life of residents staying in the OQ
After project of reducing population density succeeded, living quality of Hanoi’s
Old quarter will have precious opportunity to be improved. Therefore, the residents
should support the local government in term of buying the houses of their former
neighbour (who moved out) to increase living area. Moreover, they need to repair
and restructure the current house to improving living quality under legal framework
and preservation rules. A commitment might be made to change the situation and toforce the residents to implement. Moreover, they ought to do their duty ofpreserving historical and cultural buildings in Hanoi’s Old quarter. On the other

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Vietnamhand, local government should give favourable conditions for these people to repair
and reconstruct building under legal framework and preservation rules.
6.5. Using mass media to raise awareness of the people
It is a good suggestion for the authorities to organize community meeting topropagate of reducing population policies. These events will to make people realize
the whole profit of the policies for all of them. In order to get effectiveness, they
can use mass media to share experiences and stories of people who moved and havea better life after moving from the OQ. This solution based on trust of people on
their former neighbors, it will encourage people living in difficult conditions in the
OQ to have wise plans about their dwelling decision. Moreover, these meetings aregood circumstance for people to raise their voice, as well as for authorities tocollecting ideals.
7. CONCLUSION
The paper points out the practice of living quality in OQ. It also concentrates on an
important factor of improving living quality: the decrease of population density.
Basing on data analysis, OQ residents’ choices of moving out or staying there
depend on what economic benefits they gained from that house in the OQ. This
must be the starting point for all solutions of the government in the future.
According to the project of reducing population density in the OQ, which is
implemented by Project Management Board of Hanoi’s OQ, the objective of thescheme is reducing the population density of the area from 823 persons/ha (in 2010)
down to 500 persons/ha (in 2020). The solutions in Section 4 are expected
contributing to the success of the project, and provide a safer life, higher living
quality for residents in that significant historical and cultural area of Hanoi.
REFERENCES
Figure 1: Vietnam Association of Architects, The golden age of Hanoi - ThangLong
Figure 2: www.toulouse-hanoi.org/english/co-operation-initiatives/architecturaland-urban-heritage/
Figure 3: Project of reducing population density in the OQ, Project Management
Board of Hanoi’s OQ, 2013
MOC, Decision 70, 1995. Ministry of Construction, Decision No 70/BXD/KT-QH
dated on 30th May 1995 determined the scope of the Old Quarter.
Statistic, population census 2009. General statistics of Vietnam, The 2009
Population and Housing Census.
Hanoi People Committee, 2013. Hanoi House Development Program (2012-2020).
Hoàng Hữu Phê and Patrick Wakely 2000. Status, Quality and the Other TradeOff: Towards a New Theory of Urban Residential Location, in Urban Studies, No. 1,
Vol. 37, Taylor & Francis, England.
Quang Minh Nguyen, 2013. Social sustainability and public responsibility in
Vietnam modern city development context with Hanoi as a case study.
Sustainable Built and Environment for Now and the Future. 79-85.

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A study on post-disaster housing
by analyzing the pattern between the regional
characteristics and people’s preference
Tomoko MATSUSHITA1 and Kimiro MEGURO2
1
Graduate Student, School of Eng., The University of Tokyo, Japanmatsu-t@iis.u-tokyo.ac.jp
2
Professor, Director, ICUS, IIS, The University of Tokyo, Japan
ABSTRACT
Almost two and a half years after the 2011 Great East Japan Earthquake,approximately 290,000 people are still living in temporary housing. Local
governments are preparing to provide lots for building new houses or units ofpublic housing based on the surveys conducted of the affected people. The survey
results were similar throughout the fourteen more severely damaged
municipalities and certain patterns were observed. This paper will analyze theresults of the surveys by recognizing correlations between the regional
characteristics and peoples preferences. By extracting specific patterns foundduring the housing reconstruction process, this research aims to support policy
makers at regional level by suggesting an analysis of their geographic as well as
demographic characteristics to prepare for future disasters more effectively.
Keywords: temporary housing, post-disaster housing, the 2011 Great East Japan
Earthquake
1. INTRODUCTION
1.1 Background
Almost two and a half years after the 2011 Great East Japan Earthquake, 95% ofevacuated people still live in temporary housing (including hospitals, public
housing, etc.) while 5% live with relatives and friends and total of approximately
290,000 people need to move out from their ‘temporary housing’ by specified
time which is causing great anxiety for displaced people. The government’s latest
plan which is supposed to reflect people’s choice will provide either apartment
units or lots for building houses for approximately 130,000 people and it will takeat least next 3 to 4 years to complete.
1.2 Issues
According to the latest government plan, 24,577 ‘post-disaster’ public housing
units will be newly provided while 53,537 ‘temporary’ housing (constructed typeonly) have already been built and provided. This simply implies that 46% of the
housing is provided twice with public fund as a part of relief measures. Even639

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Vietnamthough this is merely the result of peoples preferences, it is wasteful in terms of
the use of public fund, land, time, human resources and building materials.
Buildable vacant land is scarce in the disaster-affected area and such precious land
which could possibly be used for building the post disaster housing may be taken
up by temporary housing. The data shows that in Iwate Prefecture, approximately
40% of the land used for temporary housing was privately owned and unlike othertype of land such as school grounds or parks that cannot be occupied for a longtime, privately owned land is negotiable to be used as future housing property.
The construction of temporary housing was delayed partially due to lack of land
and the same can happen for the post-disaster housing. Another serious problem
is the future maintenance issue. A majority of future occupants at newly provided
approximately 24,600 public housing are elderly and soon the local government
will face a high rate of vacancy. The central government’s policy is to provide
housing as per people’s request however the local government must take care of
the consequences of its action. This issue is only one of many problems causedby the current policy for the post-disaster housing and a better and effective
system is needed.
2. FINDINGS
2.1 Result of Survey
The surveys conducted at 14 severely damaged municipalities in Iwate andMiyagi Prefectures are selected for this analysis (see municipalities marked with *in Figure 1). In general, no significant differences amongst the municipalities
were observed. However there were a number of observations made regarding the
profile of respondents and people’s preference.
2.1.1 Profile in generalMore than half of the respondents to the surveys were aged over 60 years old andmajority of the household was two-person. This tendency of aging and smaller
household size is not surprising considering the prevailing conditions prior to thedisaster. In terms of form of housing, a majority were homeowners before thedisaster with an exception in Sendai-city where homeowners and tenants counted
about the same. A majority of respondents wishes to live and own a house again.
2.1.2 Profile by preference of temporary housing
Respondents are living either in prefabricated / constructed type or apartment typeof temporary housing. The survey revealed that those who live in the former tend
to be elderly, smaller household, low employment rate, and wish to return to theirprevious neighborhood while those who live in the latter type of housing(apartment type) tend to be younger with higher employment rate and do not wish
as strongly as the elderly to return to the previous neighborhood.
2.1.3 Profile by the age group
Younger respondents preferred to build or own their house while the elderly
preferred to move into public housing. According to the survey result in Wataritown, 90% of respondents in the 30’s wish to build a house on their own while

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72.5% of elderly respondents wished the same. This reflects the reality of the
majority of elderly’s economical condition.
2.1.4 Profile with time factor
The delay of housing provision affects people’s decisions. In Kamaishi city, agroup of researchers conducted surveys twice asking the same questions one year
apart. The results indicated that as time passed 1) more people preferred to moveinto public housing (increased from 14% to 44%), 2) single-person households
have increased (increased from 23% to 32%), and 3) households with residents
over 65 years of age have increased (increased from 47% to 52%). The reason forincrease in the number of people who wish to move into public housing can bethat people obtained more information and became more realistic in making
decisions. The increase of single-person and older household can be explained byfamilial separation. It is more convenient and sometimes necessary for young
people to stay at apartment type housing while elderly tend to stay at constructed
type that are normally built in groups. During the prolonged period of ‘temporary
life’, the young and elderly who have different agenda and priorities in life may
become separated and elderly-only household can be more prone to choose public
housing that will increase the need for construction as a result.
3. ANALYSIS
3.1 Correlation between regional characteristics and people’s preferences
The severely affected regions in Iwate and Miyagi Prefecture along the coast of
the Pacific Ocean can be categorized into two types shown as GROUP A andGROUP B in the Figure 1. Group A includes 10 municipalities in Iwate andMiyagi and these municipalities have in common a deeply indented coastal
geography and steep rise in elevation known as a rias coastline. GROUP B
includes 11 municipalities in Southern Miyagi and is characterized by a straightcoastline and flat low land in contrast to the rias coastline. Generally GROUP A
can be regarded as ‘rural’ while GROUP B is closer to ‘urban’ (or suburban)
environment.
Both groups have similar population structures and average number of household
members which is driven by the national phenomena of decreasing birthrate andaging population. However, examining the two groups by various other factors
such as property ownership and industry structure (shown in the Table 1) revealed
distinguishing characteristics both in geographic parameters as well as in people’s
preferences for housing.
The government’s housing reconstruction plan includes two main publicly funded
housing projects requested by people. Residents can request a developed piece ofland for building a house on their own or a housing unit in a post-disaster public
housing development and this decision could be correlated to the regional
characteristics. The result shows that in GROUP A, for both temporary housing
and post-disaster housing, people tend to show preference for constructing a new
structure as opposed to moving into an apartment unit. GROUP B on the other
hand shows the opposite result with higher preference for apartment type.

A study on post-disasterhousing by
the pattern
A study on post-disasterhousing by analyzing
theanalyzing
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the between
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characteristics and people’s preference641

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VietnamFigure 1: Map of affected municipalities of Iwate and Miyagi along the Pacific
Coast and the number of temporary housing provided per municipality(the source: MLIT, Reconstruction Agency, Iwate and Miyagi)

Table 1: Regional characteristics and peoples’ preferences regarding post-disasterhousing categorized by GROUP A and GROUP B
Regional characteristics & people’s
choice1) Age: 65 years old + (%)

GROUP A
‘Rural’32

GROUP B
‘Urban’
23

2.5

2.7

80 / 2073 / 2719715) Industry Type: 1st / 2nd / 3rd (%)

13 / 29 / 58

5 / 24 / 71

6) Temporary housing:
Constructed /Apartment (%)

86 / 1447 / 53

7) Post-disaster housing:Lot / Unit in Public housing (%)

56 / 44

33 / 67

2) Number of Household member (person)3) Homeowners / Tenants (%)4) Urban / Rural: Inhabitable land (%)

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3.2.1 Homeowners vs. Tenants: 3) in Table 1
Both GROUP A and B indicate a relatively high rate of homeowners, 80% and
73% respectively, compared to tenants, with GROUP A showing a slightly higher
rate. A high rate of homeownership implies that there is a relatively small stockof apartments in the region and therefore the need for constructing housing is high.
However when one looks at the rate for each municipality, Iwate Prefecture showsa high rate of homeowners overall while Sendai city and Tagajo city in Miyagi,
which are both relatively urbanized, have an average of 52% rate ofhomeownership. In Iwate with an average of 82% ownership, 58% chose to build
a new house on a lot provided by the government, while 42% chose to move into
public housing. On the other hand, in the urbanized part of Miyagi with anaverage of 52% ownership, only 17% chose to build a new house while 83%
chose public housing. This implies that homeowners tend to wish to build a houseon a lot rather than moving into an apartment unit as a tenant.
The rate of homeownership is also closely related to people’s work environment.
People tend to settle when their work is inseparable from the land as in the 1st or
2nd industry such as fishing or processing. Thus high rate of homeownership canbe translated as high rate of employment in primary and secondary industries.
3.2.2 Urban vs. Rural: 4) in Table 1
GROUP A suggests a low rate (19%) of inhabitable land while GROUP B
indicates a much higher rate (71%). This is mainly due to the geographicalcondition and in GROUP B with a high rate of ‘inhabitable land’, there is a higher
rate of people choosing apartment type of temporary housing as well as public
housing for post-disaster housing. There is a higher need for apartment stock inthe urban area naturally and this result confirms that people tend to choose theapartment type when there is a choice. This may lower the need for constructing
temporary housing or public housing, however it can also scatter the originalcommunity which could undermine the effort of recovering the damaged
community in the reconstruction process.
3.2.3 Industry Type: 5) in Table 1
According to the statistics taken before the 2011 Great East Japan Earthquake, theratio of industry structure indicated that in GROUP A, 42% were engaged in the
1st and 2nd industry while in GROUP B the ratio was lower (29%). It may be said
that the higher rate of 1st and 2nd industry implies peoples’ willingness to own ahouse rather than renting a place.
4. CONCLUSION
By analyzing the correlation between the regional characteristics and people’s
preferences, the results of this study indicated certain patterns found in the processof housing reconstruction.
Even though the Disaster Relief Act sets the procedure for providing post-disasterhousing universally at the national level, the result of this research indicated thatpeople’s decisions about housing can be preconceived to some degree by theirregional characteristics. This suggests that policy making at a regional level
rather than national level is necessary and effective. For example in the urban
A study on post-disasterhousing by
the pattern
A study on post-disasterhousing by analyzing
theanalyzing
pattern between
the between
regionalthe regional
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characteristics and people’s preference643

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Vietnamregion where people prefer to choose rental housing, finding appropriate land forconstructing temporary housing is not so necessary. Rather than negotiating andpreparing buildable land, it may be more effective for the local government tomake arrangements with real estate industry. On the other hand, in rural areas,since people prefer constructing a house rather than renting it, it may bereasonable to plan and construct temporary housing with the intention of selling as
public housing in the future at lower cost. This would help to ease the issue of“double” public funding by effectively eliminating the extra cost and time.
A correlation was identified by factors that are indicative of natural environment
such as homeownership, the rate of inhabitable land or industry type. However
there should be other factors that are more personal that influence people’s
preferences thus further research is required.
REFERENCES
Reconstruction Agency. 8.22.2013. Total Number of Evacuees.
Ministry of Land, Infrastructure, Transport and Tourism (MLIT). 4. 1. 2013.
Construction Situation of Temporary housing.
MLIT. 2.4.2013. Number of private rental housing leased as temporary housing.
MLIT. 6.30.2013. Housing Reconstruction Schedule. <http://www.mlit.go.jp/toshi/toshi-hukkou-arkaibu.html> (accessed 8.2013)
Iwate prefecture. 2.7.2012. Complete List of Temporary Housing Constructed in
Iwate. http://www.pref.iwate.jp/~hp0608/F_eizen/3rd/kasetsu.pdf (accessed
8.2013)
Rikuzentakata-city. Residents Intention Survey 8-9.2012.
Research group on Kamaishi-city. Residents Intention Survey 7-8.2011.
Research group on Kamaishi-city. Residents Intention Survey 7.2012.
Ofunato-city. Residents Intention Survey. 4-5. 2012.
Miyako-city. Residents Intention Survey. 11-12.2013.
Otsuchi-town. Residents Intention Survey. 1.2012.
Yamada-town. Residents Intention Survey. 2.2012.
Sendai-city. Residents Intention Survey. 4.2012.
Ishinomaki-city. Residents Intention Survey. 2-3.2012.
Kesennuma-city. Residents Intention Survey. 7-8.2012.
Higashi-Matsushima-city. Residents Intention Survey. 2-3.2012.
Watari-town. Residents Intention Survey. 7.2012.
Watari-town. Residents Intention Survey. 10-11.2012.
Yamamoto-town. Residents Intention Survey. 6-8.2012.
Onagawa-town. Residents Intention Survey. 7-11.2012.
Onagawa-town. Residents Intention Survey. 7-8.2012.
Minamisanriku-town. Residents Intention Survey. 12.2011-1.2012.
Ministry of Internal Affairs and Communications Statistics Bureau. 6.3. 2013.
Statistical Observations of Shi, Ku, Machi, Mura. <http://www.e-stat.go.jp/SG1/
estat/List.do?bid=000001046053&cycode=0> (accessed 8.2013)

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Proposed solutions to quality improvement
and integrated operations of technicalinfrastructure systems for new urban areasin Vietnam
Ngoc Khoa HO1, Hong Hai TRAN2 and Nguyen Van Phuong PHAM3
1
Phd, Faculty of Building and Industrial Construction,
National University of Civil Engineering, Vietnam
hnkhoa@yahoo.com
2
Phd, Faculty of Building and Industrial Construction,
National University of Civil Engineering, Vietnam
3
Msc, Faculty of Building and Industrial Construction,
National University of Civil Engineering, Vietnam
ABSTRACTIn recent years, in Vietnam, along with economic and population growth, thedemand for housing and community living space have rapidly increased, leading
to urbanization trend and the development of new urban areas and megacities.
Technical infrastructure in urban areas is a basic system consisting of particularfunctional components that operate continuously during the whole service life of
the areas. Construction of urban technical infrastructure therefore plays animportant role. However, the majority of urban infrastructure project has faced
various problems relating to quality and integrated operation, which can affectproject investment efficiency negatively. The paper examined these issues andproposed solutions to improve the quality and ensure the integration of technicalinfrastructure systems in megacities’ urban areas under Vietnamese conditions.
Accordingly, the solutions could be applied in reality and contribute significantly
to the enhancement of investment effectiveness for that kind of project.
Keywords: Technical infrastructure, integration, new urban areas, megacities
1. INTRODUCTION
In recent years, the world has witnessed unprecedented population growth inhuman history. The world population has been approximately 7 billion by 2013
and is expected to reach 10 billion by 2025 (Seitz, 2008). The world’s population
is becoming increasingly urban. There are many megacities with a population ofover 10 million people have been formed. By 1950, the world counted two
megacities, New York with 12,3 million and Tokyo with 11,3 million. After 60
years, there were 23 megacities, including 12 Asian megacities. The United
Nations (2012) projected the number of Asian megacities will increase to 21 by
2025. Particularly, big cities such as Chongqing, Guangzhou, Jakarta, Lahore, andShenzhen are predicted to reach 10 million people quickly. According to megacity
definitions, Vietnam does not have any megacity; however, with rapid
urbanization and population growth, it cannot be doubt that numerous cities arepotential to become megacities in the future.

645

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VietnamWorld Bank (2006) stated that urbanization is an indispensable trend and essential
motivation for economic growth of nations. Urbanization and long-term
development of an economy have a well-known positive relationship, driven byachievementsfromindustrialization,commercialization,
productivity
improvement, employment opportunities, development of infrastructure and otherfacilities. Nations with higher levels of urbanization invariably have higher levelof per capita income (World Bank, 2006).
Infrastructure is the heart of urbanization process. According to Le (2012),
sustainable urbanization must proceed with the harmony of economic, social
development, ecological protection, and appropriate infrastructure systems thatcreate close connections between rural and urban areas. In particular, technicalinfrastructure is a key factor in order to achieve sustainability. Successful lessonsof developed countries show that technical infrastructure built synchronously andmodern is a material prerequisite for urban development. Sufficient technicalinfrastructure can help in improving living quality of urban residents, reducing
poverty, narrowing gaps between developed and backward regions, and support
economic growth (World Bank, 2006; Nagesh and Prabir, 2008).
World Bank (2006) recommended that during urbanization process, as adeveloping country, Vietnam should call for more investments in technicalinfrastructure development. In 2012, the Vietnamese Government highlighted that
construction of urban infrastructure is one of the core investment areas insustainable development strategy to 2020. During last 12 years, although the total
investment for technical infrastructure projects accounted for 10% of GDP, urban
cities have still faced many weaknesses of technical infrastructure systems(Nguyen, 2010). In Vietnam, urbanization took place early but in recent years, it
has grown rapidly. Hoang (2013) identified that existing urban technicalinfrastructure has been showing poor quality, rapid degradation, and lack ofintegrated operation. Therefore, it is vitally important for finding out reliable
solutions that could help ensure quality, integrated operation, stability, andsustainability of technical infrastructure components in new urban development
projects as well as take into account the ability of connecting with other regions
and enlarging spaces in response to urban development in the future.
This paper firstly will focus on examine the status of Vietnamese urban technicalinfrastructure. Difficulties and challenges arising from the implementation of
infrastructure construction projects will be identified and analysed. The paper thenwill propose some solutions in order to improve quality, integration of urban
technical infrastructure components, and enhance investment effectiveness of forthat kind of project, towards sustainable urban development.
2. THE DEVELOPMENT AND CHARACTIRISTICS OF NEW URBAN
AREAS IN VIETNAM
2.1 The status of urbanization process in Vietnam
In recent years, the pace of urbanization in Asia has become faster. Althoughurbanization in Asia had a relatively low starting point, it has taken place

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increasingly on a large scale compared to other regions. Asian Development Bank
(2011) predicted that the process would continue to rise until 2050, in which thenumber of megacities as well as the size of cities will rise rapidly, including
Hanoi and Ho Chi Minh City of Vietnam.
After the administrative boundary expansion by 2012, Hanoi’s population reachedto 6,87 million. Hanoi are about 7.1 million people and is expected to reach about
8,1 – 9,2 million by 2020 based on the fluctuation in population growth Urban
spatial development of Hanoi is oriented towards the model of urban clusters
including five satellite towns: Hoa Lac, Son Tay, Xuan Mai, Phu Xuyen and Soc
Son. These towns and the centre are separated by green corridors, linked together
by road belts and roads oriented to the central city, and belonged to the regionaland national transport network (Vietnamese Government, 2011).
According to development strategies, Ho Chi Minh City will meet criteria forbeing a modern metropolis by 2020 (Ho Chi Minh City’s Committee, 2012). The
city’s population will increase to approximately 10 million people by 2025. At thesame time, there will be four new urban areas formed, namely Thu Thiem, Hiep
Phuoc, Tay Bac, and Sai Gon Hi-Tech Park. Elevated railway system, railway forspecial purposes and highway bridges crossing Dong Nai, Sai Gon, and Nha Be
rivers are expected to complete. Ho Chi Minh City Area will be constructed,
including a nucleus (consisting of Ho Chi Minh City and some neighbourhoods)
and five satellite towns for developing towards nearby provinces such as Dong
Nai, Ba Ria – Vung Tau and Binh Duong. It is expected that population of Ho Chi
Minh City Area will reach about 20 – 22 million by 2020.
Generally, urbanization process in Vietnam has increased rapidly, in particular thenumber of urban areas. Last century, there were about 600 urban areas, now thisfigure rises to more than 750, and is predict to reach 1000 by 2025 (Hoang, 2013).
The urbanization rate is leading to rapid urban population growth whereas despite
significant improvements, urban infrastructure systems are becoming unable tosatisfy residents’ requirements, and come under pressure increasingly. It isessential to take into account two answers for these problems, including: firstly,
existing technical infrastructure is incapable of meeting the needs of urbanization
growth; and secondly, technical infrastructure in new urban areas presents many
limitations, for example, poor quality, lacks of operational integration andflexibility in association with the existing systems.
2.2 The development and characteristics of new urban areas in Vietnam
Vietnamese regulations define a new urban area as a part of city territory, with thehigh degree of integration of technical, social infrastructure, residential buildings
and other service facilities. It may be either the expansion of an existing urban
area or a completely new urban zone that has its own boundaries and determinedfunctions in accordance with urban plans approved by the government. Its
administrative boundaries belong to a province (Vietnamese Parliament, 2009).
The majority of new urban areas projects must comply with Construction Law,
Decrees on investment and construction management, and other related legal
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Vietnamdocuments. In fact, these documents are not brought up-to-date in order to beappropriate for rapid urbanization. Additionally, policies on land management,compensation and acquisition are not adequate. The level of construction andmanagement is low. As a result, these projects have not been delivering
successfully. The size and quality of technical infrastructure systems seem not tosatisfy requirements of social infrastructure development and residents’ demands.
Most of urban projects are delayed frequently.
According to statistics made by Vietnamese Construction Ministry, the country
currently has around 2,500 new urban projects that are mainly residential, officebuildings and other properties. In Hanoi, there are more than 800 projects with anarea of about 75,189 ha. Urbanized and residential areas account for nearly 390
projects with an area of 39,000 ha. Ho Chi Minh City counts about 1,400 projects
with an area 4,490 ha. Meanwhile, Hai Phong City approves approximately 260
projects with the nearly 2,600 ha of land, and 100 projects have been implemented
and generate approximately 700.000m2 contributing to the city's housing fund. Da
Nang City invests in more than 120 projects of constructing new urban zones,
offices, commercial and residential buildings with an area of about 2,300 ha.
However, 19 provinces still do not have any urbanized area. There are main
characteristics in urban development process found, as follows:
Regarding to customer focus, new urban zones primarily serve needs of thosewith high incomes while the main objective of urbanization strategies is to address
demands of housing, living spaces for all different people groups, including thosewith low incomes. However, it seems that this objective is unlikely to achieve due
to various reasons in terms of economic, social and custom issues.
Regarding to land acquisition, there are many problems causing a waste of timeand money of all involved stakeholders. Their reasons mainly come from the lackof coordination among related authorities. Investigations for planning landacquisition are conducted slowly. Compensation for damages to residents’properties is not reasonable. In various projects, compensation process did notcarry out overtly. Adjustment policies made by the government leading to avariance of compensation resulted in residents’ claims and disagreements.
Regarding to urban design, master plans seem to be inappropriate. For example,
urbanized areas mostly present inadequate layout of spaces. Low-rise buildings
are situated alternately among tall buildings, or high-rise buildings are locatedmainly either along arterial roads or surrounding the boundary of urbanized areas.
Master plans also do not take into account an idea of making a high-rise building
complex become the highlight of an urban area. Approval process of architecturaldesign always requires the harmony of architecture and climate and landscape ofurbanized regions. However, in current practice, architecture of new urban areas isof poor quality with undefined and irrational styles, using many colours andboring box-shaped buildings. Urban designs show the lack of breakthrough ideasthat can create different and original characteristics of a new urban zone. Besides,
residential buildings account for the majority of a total urbanized area whereas theland area for social infrastructure, static traffic system, plants and trees, squares
and lakes is limited.

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Regarding to the quality of technical infrastructure and its operation, there aresome serious problems. Due to the rapid development of new urban projects,
infrastructure construction is of poor quality and lacks the consistency between
new and existing systems. Drainage systems generally do not guarantee
operational capacity as required. Flooding occurs frequently during the rainyseason. In Hanoi, new urban areas such as Trung Hoa - Nhan Chinh, My Dinh,
and Keangnam Complex, often face flooding after heavy rains, because of
insufficient investment in drainage systems, lacks of integration and flexibility
with existing systems and the nature of low-relief land areas. In many urban zones,
wastewater treatment plants are putting pressure to meet defined requirements,
causing the phenomenon of discharging wastewater directly into sewers, ponds
and lakes. Consequently, the urban environment has been polluted, affecting thequality of residents’ life adversely. “Dead pits” caused by local subsidence ofurban transportation system due to poor quality of construction works arereceiving negative feedback of the society. New urban zones are often located insuburbs. Therefore, excluding fence systems constructed, during site preparation
investors have to face difficulties relating to traffic, water supply, and electricity.
The handover of technical infrastructure components to clients do not provide
enough all their operational relevant documents. Warranty and maintenanceactivities are not effective and efficient.
3. THE STATUS OF QUALITY AND INTEGRATION OF TECHNICALINFRASTRUCTURE SYSTEMS IN NEW URBAN AREAS
Urban infrastructure consists of social and technical components. Social
infrastructure are residential buildings; public service facilities for health care,
culture, education, entertainment, sports, parks, commercial purposes and others;
and buildings for urban administration works. Technical infrastructure includes
the following items: transport system, surface water drainage system (drains,detention reservoirs, storm-water pump stations), sewage system (sewers,
wastewater treatment plants), water supply system (water supply plants, pipelines,
pump stations - tanks), power and gas supply system, lighting system,
communication and telecommunication system, and tunnel engineering system(Choguill, 1996; Hardwicke, 2008; Vietnamese Construction Ministry, 2012).
Technical infrastructure is defined as a system including particular functional
components that are first built and operate continuously during the whole service
life of an urban area. The quality and efficiency of technical infrastructure will beenhanced when all their components are integrated and linked closely.
The status of poor quality and integration of technical infrastructure of new urban
areas in Vietnam comes from many perspectives at all stages of investment
process, particularly management mechanism, legal documents, and problems inproject planning and implementation. Owing to a diversity of scales, nature,investment capital, client requirement and duration, as well as impacts of acomponent upon others, technical infrastructure system needs to be managed
strictly by stakeholders during and after investment process.

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3.1 Management mechanism of government authorities
Inadequate legal documents: Although there are numerous legal documents about
urban planning, construction investment and quality management, in fact,
Vietnam still lacks a legal document system for technical infrastructure projects,
which is holistic and comprehensive, in order to create favourable conditions for
related authorities and parties involving in construction activities.
Lack of inspection and supervision during construction process of stakeholders
who directly operate technical infrastructure components: After construction
process, project products will be handed over to different local authorities tooperate and manage in relation to their functions. For example, transportation
authorities of urban zones are responsible for managing transportation systems.
Nevertheless, during project implementation phase, the respective related
authorities did not play a vital role in inspection and supervision works. Therefore,
they do not fully comprehend the real status of project quality.
3.2 Problems in project planning phase
Poor quality of project planning: In various projects, detailed master plans ofscale 1:2000 and 1:500 do not present clearly the predictability of motivations andopportunities supporting for development of urban zones, and do not consider
variations of economic and social factors, especially urbanization and migration
growth. Thus, many detailed master plans have to be adjusted, leading to a wasteof time and money and affecting investment efficiency. Besides, urban planning is
conducted by the Planning Institute (under the Department of Planning –Architecture of a city or province) based on client requirements. This department
is also responsible for evaluation and approval of the scheme. Therefore, urban
planning process is not transparent and effective.
Inappropriate capacity of consultants: To plan an urban development projectrequires many knowledgeable experts from different majors for example, finance,
environment, technology and construction. Especially, the participation ofcompanies, professionals with experience in infrastructure construction during the
project planning and project evaluation phases is vitally important. However,many consultants, who do not have essential capacity and experience, are often
involved in the projects because of bidding assignment or becoming the bidding
winner by using the virtual profile. Data investigated in project planning are
generally not reliable, and mostly replicated from other projects. Planningdocuments therefore do not meet defined requirements and affect project successseriously.
Limited predictability of socio-economic development growth of urbanized areas:
Findings from investigations of economic and social factors (inflation, land andconstruction costs and urbanization rate) are initially not accurate and useful for
project planning. The whole project particularly implementation phase thus will
face challenges such as price fluctuations, inflation, cost overrun, policy
adjustments, rapid urbanization, interest conflicts and land acquisition difficulties.

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In fact, after handing over, many projects have not achieved economic efficiency
as planned and deteriorated quickly.
Inadequate basic design of technical infrastructure: Basic design schemes are
cursory and sketchy. They do not reflect in actual conditions and provide
sufficient evidence in order to deploy next design steps. Many projects have tovary design solutions from basic schemes and calculate total investment capitalagain. While carrying out basic design, clients often do not have sufficientgeological data because they are unable to conduct surveys in land areas withoutownership. They therefore replicate other nearby projects’ geological findings.
Obviously, this phenomenon is the cause of inadequate basic design schemes.
3.3 Problems in surveys, engineering design and construction drawings
Poor quality of geological, topographical and hydrological surveys: In many
infrastructure projects, surveys are not supervised and inspected closely, andneglect many important stages. Drilling data provided by surveying consultants
largely do not meet basic requirements of design works. Meteorological andhydrological specifications are not studied and applied properly especially fordrainage systems and detention reservoir projects.
Lack of inheritance and development of basic design schemes: Basic design
scheme plays a key role in producing engineering and construction drawings.
However, many projects do not comply with prime principles highlighted in basic
designs such as technical specifications, sizes and boundary lines, therefore
approval processe must lengthen to adjust and amend these documents.
Inappropriate indicators of technical infrastructure and project scale: During
implementation stage, many projects are allowed to vary from the original scheme
approved, by the increases in building density, the number of floors, plot ratio andurban population size. Meanwhile, specifications of technical infrastructure still
depend on the original basic design, without any adjustment in accordance withthese changes. Thus, urban technical infrastructure will become overloaded andcannot satisfy residents’ demands.
Limited synchronization and integration of technical infrastructure components
when designing: Owing to inadequate design led by clients’ ineffective
management, there are a plenty of significant adjustments in implementation
phase that result in wastes of money and time. In fact, normally engineering
design works are responsible by different consultants without discussion or
coordination among them. The lack of integration of infrastructure components inengineering designs could cause serious omissions, considerable overlaps andproject delays that affect project quality directly during construction phase.
3.4 Problems in construction phase
Improper land acquisition and construction schedule: In various projects,
schedules of land acquisition and construction do not present any connection andconsistency. Because of the complex nature of land acquisition, many clients
Proposedsolutions
to quality improvement
andoperations
integrated operations of technical
Proposed solutions
to quality
improvement
and integrated
infrastructure
systems
for
new
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in
Vietnamof technical infrastructure651

October
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Vietnamcannot be active in deploying and controlling the schedule while construction
schedule is prepared improperly. In some actual cases, construction phase muststop unexpectedly due to disagreements of those who are influenced directly byland acquisition; or construction equipment, machines and materials are gathered
but there is not enough space at the site to place them because land acquisition
does not finish.
Poor quality of construction works: There are serious problems in construction
phase of urban infrastructure projects. Firstly, technical infrastructure system isdesigned in linear form with different altitudes and many intersecting points. Thus,
the amount of earth works is considerable and affected directly by weather andhydrology factors. Secondly, despite undertaking construction works, a main
contractor handovers their tasks to other subcontractors and get the variance ofcontract prices. This phenomenon could reduce the actual capital value and cause
numerous difficulties in managing project quality. Thirdly, there is a variety ofcontractor and supervision consultant performing in the site at the same time.
Their cooperation and communication seem to be limited; therefore, if there is any
problem occurring and their works overlap others then it is difficult and takes time
to solve. Another issue is that project management units do not have theappropriate capacity to control and monitor effectively construction activities.
Ineffective supervision: In infrastructure projects, supervision consultants often
show the limitations of manpower and qualifications to achieve client satisfaction.
Processes of checking, inspecting and approving construction works, equipment,machines and input materials are often undertaken cursorily with poor teamwork.
Limited connection with existing technical infrastructure: One of the mostsignificant challenges in urban zones is that the new infrastructure built does not
integrate with existing infrastructure systems nearby or beyond the urban area. In
many urbanized zones, the integration of their technical infrastructure systems is
paid more attention than others located beyond the boundary.
4. SOLUTIONS TO QUALITY AND INTEGRATION IMPROVEMENT OFTECHNICAL INFRASTRUCTURE SYSTEMS IN NEW URBAN AREAS
Based on the analysis of status and reasons for poor quality and limited
integration of urban technical infrastructure systems in Vietnam, it can be seenthat the management of authorities and clients, and the capacity of consultants andcontractors play important roles. Accordingly, this study identifies two solutiongroups in order to help improve the effectiveness of urban infrastructure projects.

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Solutions

For problems
relating togovernment
management
Project planning

For problems relating toproject stages

Project design

Construction

Figure 1: Solution groups for improvement of urban infrastructure systems
4.1 Solutions for problems relating to government management
It is vitally important to enhance the Vietnamese Government’s role in urban
planning, monitoring and controlling all project activities in order to improve
quality and integration of technical infrastructure systems in new urban zones.
This below figure presents three proposed solutions to handle with problems
coming from ineffective management of the Government.

Solutions forproblems
relating togovernment
management

Issue regulations on planning, checking, and approving
procedures of detailed master plans (scale: 1:2000,
1:500)
Issue decrees, regulations on quality management ofurban technical infrastructure projects
Issue regulations on inspection of operation
organizations that exploit urban technical infrastructure
after handover

Figure 2: Solutions for problems relating to government management
4.2 Solutions for problems relating to project stages
There are four solutions proposed for project planning phase (shown in figure 3).
The first solution concerns about how to improve quality of detailed master plansof scales 1:2000 and 1:500 and to reflect actual conditions of projects. Therefore,
it is essential for clients in selecting appropriate consultants and the third party
responsible for checking consultants’ tasks and give advice prior to submission
for approval. The second is to improve the predictability of economic-social
development of urban zones. Clients should be allowed to be active in managing
financial risks, land acquisition, interest conflicts led by changes in master plansand project schedule due to policy adjustments. Thirdly, the construction of urban
technical infrastructure should be considered as an independent project and ensurethat it will be deployed shortly in accordance with land acquisition schedule. Thissolution will enable clients to focus more on project management and quality
improvement. Another solution is to improve the accuracy of basic design schemethat is vitally important for ensuring the efficiency of engineering andconstruction drawings in next project stage.
Proposedsolutions
to quality improvement
andoperations
integrated operations of technical
Proposed solutions
to quality
improvement
and integrated
infrastructure
systems
for
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in
Vietnamof technical infrastructure653

October
2013, 2013,
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Vietnam1) Quality improvement of detailed master plans (scale: 1:2000,
1:500)

Appropriate selection of consultants
Check, ask for advice before submission for approval
Effective procedures of checking and approving

Solutions forproblems
relating toproject
planning phase2) Improve predictability of economic-social development of new
urban areasSufficient survey of economic-social conditions in the area
Investigate the status and trends of development
Investigate government mechanism and policies
Appropriate selection of consultants conducting projectplanning activities
3) Consider urban infrastructure construction as an independent
project of the whole urban construction project.
After the whole project approved
After detailed master plan of scale 1:500 approvedCarried out in accordance to land acquisition schedule4) Quality improvement of basic design schemes
Improve management skills of clients
Improve efficiency of surveys for basic design works

Change participants who prepare basic design:, calls for
involvements of experienced experts, organizations.

Improve efficiency of the approval process of basic design

Figure 3: Solutions for problems relating to project planning phase
There are three solutions proposed for the production of engineering andconstruction drawings. The efficiency of surveys should be paid more attention tocollect accurate and reliable data for preparing the drawings. The synchronizationand integration of infrastructure components presented in design documents playconsiderable roles. They should inherit and develop from basic design scheme by
selecting a general design-construction contractor and appropriate chief engineers.
Additionally, to enhance the quality of approvals, the role of consultants who
approve design documents and the compliance of approval procedure are essential.
1) Quality improvement of geological, topographical and hydrological surveys
 Additional surveys for creating inadequate construction design
 Changing implementation procedure: contractors conduct surveys according
to design consultants’ requirements.
 Monitoring surveys and inspecting the findings carefully
Solutions forproblems
relating to thephase ofproducingengineeringandconstruction
drawings

2) Ensure the synchronization and integration of infrastructure components indesign documents
 Prefer design consultants to continue preparing construction drawings.
 Select a general contractor responsible for design and construction works
 Do not separate infrastructure components into different design packages
executed by different consultants
 Ensure the relationship between infrastructure design and the whole projectscale, particularly if any adjustment.
3) Quality assurance of approval procedure of design documents
 Improve management capacity of clients
 Select adequate consultants responsible for approvals
 Define prerequisites for approvals to construction drawings of infrastructurecomponents and related others which are located in a same urban area, forinstance: integration, important information relating to infrastructurecomponents, and solutions for intersecting points.

Figure 4: Solutions for problems relating to engineering and construction
drawings

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With regard to problems occurring in construction phase, there are four solutions
identified. Firstly, it is essential for clients (or project management units) to
become effective in managing projects by building a qualified manpower structure,
applying appropriate management models and methods. Land acquisition
completed on schedule is considered as a prerequisite for deploying construction
works. To ensure construction quality, clients should prefer to select a generalcontractor to build all infrastructure components instead divided them into small
packages with different subcontractors. Besides, the selection of a generalsupervision consultant for the whole project instead of employing various
supervision organizations is more effective in ensuring the quality of construction
works. The involvement in supervision activities of organizations responsible for
operation of infrastructure systems should be obligated.
1) Improve the capacity of clients (or project management units) Management skills (training, education, applying management models) Qualified manpower (education, recruitment) Employ professional project management consultants2) Complete land acquisition on schedule Resource mobilization (capital, manpower, coordination of authorities)
 Appropriate and flexible application of policies
 Monitored closely and timely by clients Adjust construction schedule in accordance with land acquisition schedule

Solutions forproblems
relating toconstructionphase3) Quality assurance of construction works
 Prioritize application of the general contractor model Infrastructure components that may intersect or be linear have to beconstructed simultaneously Apply advanced methods of project management such as ISO, TQM
 Require organizations that operate infrastructure components to involve in
inspection of construction works
 Strengthen design consultants’ inspection activities Plan adequate connections between new and existing infrastructure items

4) Ensure the efficiency of supervision activities

 Apply the model of general supervision consultant
 Enhance the role of clients in managing supervision activities
 Select qualified and experienced supervision consultants
 Comply with supervision procedures and regulations
 Require the involvement of organizations that operate infrastructurecomponents in supervision activities

Figure 5: Solutions for problems relating to construction phase
5. CONCLUSIONS AND RECOMMENDATIONSIn Vietnam, urbanization growth has associated with the national strategies ofindustrialization and modernization. In recent years, urbanization has increased
rapidly and begun to reveal a variety of limitations. The number of urbanizedzones and the density of urban population have risen dramatically. These issues
have led existing technical infrastructure systems become overloaded. Besides,
although the government has paid considerable attention, limited integration andsynchronization of technical infrastructure components have not been addressed
yet. The main reasons identified include ineffective management of authorities,
inappropriate basic design schemes and limited predictability of economic-social
development of an urban area during project planning; inaccurate data collected
Proposedsolutions
to quality improvement
andoperations
integrated operations of technical
Proposed solutions
to quality
improvement
and integrated
infrastructure
systems
for
new
urban
areas
in
Vietnamof technical infrastructure655

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamfrom surveys, insufficient engineering and construction drawings, difficulties ofland acquisition and poor quality of supervision activities.
Through the status of rapid urbanization and challenges of implementing technicalinfrastructure projects, it is assumed that Vietnamese urban areas have been facing
unsustainable development. In order to strengthen the effectiveness of managing
that kind of project, which contributes to the success of urban development
strategies, it is important to apply multiple solutions. First solution group
comprises the enhancement of Government role in urban planning, introduction ofadequate legal documents and regulations on urban construction issues. Anothergroup is to handle with issues during project planning, preparation of design
documents and construction phase.
Economic – social development of the country in general and urbanized zones inparticular, have a close relationship with sustainable technical infrastructure
systems. Therefore, successful technical infrastructure project should be one of
the most important national concerns that need to be focus. Further researches
should be conducted to evaluate the effectiveness and ability of applying these
proposed solutions in reality under Vietnamese conditions.
REFERENCES
Asian Development Bank, 2011. Asia 2050: realizing the Asian Century.
Choguill, C., 1996. Ten steps to sustainable infrastructure. Habitat International,
20(3), 389-404.
Hardwicke, L., 2008. Transition to smart, sustainable infrastructure. In P. W.
Ho Chi Minh City’s Committee, 2012. Master planning project of economicsocial development of HCMC in 2020, vision to 2025.
Hoang, C. L., 2013. Difficulties in urbanization process in Vietnam. Journal of
economy and forecast 11.
Le, H. K., 2012. Urbanization and sustainability. Journal of VietnameseArchitecture 3, Hanoi.
Nagesh, K. and Prabir, D., 2008. East Asian Infrastructure development in acomparative global perspective: an analysis of RIS infrastructure index. ERIA
research project report 2007-2, IDE-JETRO, Chiba, 7-28.
Newton (Editor), Transitions: Pathway towards sustainable urban development inAustralia, CSIRO Publishing, Victoria, 599-608.
Nguyen, X. T., 2010. Challenges of Infrastructure in Vietnam. Phu Sy, Hanoi.
Seitz, J. L., 2008. Global issues: An introduction, 3rd Edition. Blackwell
Publishing, Malden, Oxford, Victoria.
The United Nations, 2012. World urbanization prospects: the 2011 revision.
World Bank, 2006. Vietnam’s Infrastructure Challenges.
Vietnamese Parliament, 2009. Urban planning law.
Vietnamese Construction Ministry, 2012. National technical regulation on rulesof classifications and grading of civil and industrial buildings and urban
infrastructures.
Vietnamese Government, 2011. Decision No 1259/QĐ-TTG on approvals of
Hanoi planning in 2030 and vision to 2050.

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Study on applicability of
remote building damage assessment system
for large-scale earthquake disasters- Focused on the photo upload system Makoto FUJIU1, Miho OHARA2 and Kimiro MEGURO3
1
Project Researcher, Institute of Industrial Science,
The University of Tokyo, Japanfujiu@iis.u-tokyo.ac.jp
2
Associate Professor, International Center for Urban Safety Engineering (ICUS),
Institute of Industrial Science / Interfaculty Initiative in Information Studies,
The University of Tokyo, Japan
3
Professor, International Center for Urban Safety Engineering (ICUS),
Institute of Industrial Science / Interfaculty Initiative in Information Studies,
The University of Tokyo, Japan
ABSTRACT
Building damage assessment is necessary for governments to issue the Victim
Certificates for residents who suffered from housing damages. The process ofassessment needs quickness, efficiency, accuracy, objectivity and fairness because
the results of the assessment are used as the criteria for providing public
monetary supports for rebuilding their livelihood. In order to solve the problems
with building damage assessment in the past disasters, authors have proposed a
new assessment system using photos of damaged houses taken by residents or
volunteer fire corps in damaged area.
The proposed remote building damage assessment system consists of four subsystems: photo uploading system used inside damaged area, remote assessment
system for supporting experts such as registered inspectors outside damaged area,e-learning system for users and Web-GIS server located outside damaged area
under cloud condition. Although the authors have already developed a prototype
system, the evaluation of its effectiveness was not fully done. Then, in thisresearch, operation trial was conducted in order to verify applicability of thedeveloped photo upload system as a part of remote building damage assessment
system. As a result, it became clear that the developed system have enoughresolution to determine damage level of the houses.
Keywords: earthquake disaster, building damage assessment, smartphone, IT
1. INTRODUCTION
In Japan, several big earthquakes are expected to occur in the near future. A lot ofstructural damages due to these earthquakes will cause enormous needs forbuilding damage assessment. Building damage assessment is necessary for657

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Vietnamgovernments to issue the Victim Certificates for residents who suffered housing
damages. However, current number of human resources who are trained with theprocedure of building damage assessment is not enough. The result of building
damage assessment is used for issuing the victim certificate. Then, the building
damage assessment during large-scale earthquake disaster requires some
performances such as quickness, efficiency, accuracy, objectivity and fairness.
The guidelines of general procedure for inspecting building damage andevaluating loss due to disasters were published by the Cabinet Office in 2001 and2009. Tanaka (2008) pointed out various problems of building damage assessment
such as inaccurate inspection, difficulty in quick inspection and lack of humanresources with sufficient skill of assessment in past disasters.
Considering the future risk of big earthquakes, it is necessary to develop a new
system which can correspond to next large-scale earthquake disaster. So far, Fujiu(2012) has proposed new remote system for building damage assessment using IT
system and developed its prototype system. These systems have some featuresthat can solve some problems pointed out at the past building damage
assessments and execute building damage assessment with quickness, efficiency,
accuracy, objectivity and fairness after a large-scale earthquake disaster. The
proposed system consists of four sub-systems as shown in figure 1: photo
uploading system used in damaged area, assessment system for supporting experts
such as registered inspectors outside damaged area, e-learning system for users
and Web-GIS cloud server located outside damaged area. Although the authors
have already developed a prototype system, the evaluation of its effectiveness was
not fully done. Then, in this research, authors conduct an operation trial to verify
the usability and resolution of photos of the developed photo uploading system.
This trial aims to verify applicability of photo upload system as a part of remotebuilding damage assessment system.
System２
Remote assessment system
for specialists

System１
Photo upload systemin damaged area
Residents

Architect

Interactive
condition

Smartphone

Region B Execute theRegion A

building damage Architectassessment Experienced

Region C

Volunteerfire corps
Provide some
information

System3
e-learning
systempersonExperienced
person Region E

Region D

Photo upload ofdamaged house

Provide GIS
information anddamaged photo

Input thedamage level

Arrangementof inspectors

Evaluationof training
resultManagement of damaged photo, inspector’s name, GIS information, progress of building
damage assessment and so on.

S�stem� �eb�GIS cloud server

Figure 1: Concept of remote building damage assessment system

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2. OUTLINE OF DEVELOPED PHOTO UPLOAD SYSTEM IN REMOTE
BUILDING DAMAGE ASSESSMENT SYSTEM
2.1 Flow of building damage assessment
After the request from residents of damaged houses, building damage assessment
is executed based on building damage assessment guideline, issued by Cabinet
office in Japan. Figure 2 shows the flow of building damage assessment based on
the guideline. The building damage assessment has three steps; the first one is theoverview judgment which is the judgment of the building damage from theoverview, the second one is the inclination judgment which is the measurement of
the building inclination, and the third one is the building element judgment whichis the measurement of the damage level and the damage area of roof, wall andfoundation. In each step, the damage ratio is calculated based on the building
damage level and the building damage area. When the damage ratio reaches thestandard value in each step, the damage level is decided as major damage, majormoderate damage, moderate damage or minor damage.
Ⅰ Overview judgment
A: The house is totally collapse.
B: A part of floors in the house is collapse.
C: A part of foundation in the house is broken by liquefaction.
Not applicable

Major damage

Ⅱ Inclination judgment（Damaged ratio
50％ over)

Inclination of external walls is over 1/20.
Not applicable

Ⅲ Building elements judgment (roof, wall, foundation)
The damage ratio of fundamental is over 75%.
Not applicable

Over 50％

Major damage

The damage ratio of thedamaged house

From 40% to less than 50%

Major-moderate damage

The damage ratio of thehouse is calculated fromthe damaged elements.

From 20% to less than 40%

Moderate damage

Less than 20%

Minor damage

Figure 2: Flow of building damage assessment (Primary inspection)
Judgments of damage level and calculation method of damage area are explainedin this paragraph as an example of damaged wall. Each damage level has a basic
damage ratio. Figure 3 shows the relationship between damage level and basic
damage ratio. The damaged wall has small and short crack as shown in Figure 3a,and the corresponding basic damage level is evaluated as 10%. The damaged wall
has a long crack and small peeling off of the wall facade as shown in Figure 3b,
and the corresponding basic damage level is evaluated as 25%. The damaged wall
has a long crack and medium peeling off of the facade as shown in Figure 3c, andthe corresponding basic damage level is evaluated as 50%. The damaged wall has
peeling off of greater part of the exterior wall facade as shown in Figure 3d, andbasic damage level is evaluated as 75%. The damaged wall has peeling off ofalmost the whole wall facade as shown in figure 3e, and the corresponding basic
damage level is evaluated as 100%. The damaged area is calculated based on thedecomposition method. The method is decomposition of the damaged wall to
calculate the damaged area as shown in Figure 3f. The red dotted line shows thedecomposition line of the damaged wall. If there is some damage in one part, thepart is defined as a damaged part.
Study on applicabilityof remotebuilding
damage systemassessment
system for large-scale
Study on applicabilityof remote building
damageassessment
for large-scale
earthquake
disasters
Focused
on
the
photo
uploadsystemearthquake disasters - Focused on the photo upload system -659

October
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Vietnam

Basic damage ratio: 10%
Damage level:1

Basic damage ratio: 25%
Damage level:2a) Small and short crack of the wall
facadeb) Long crack and small peeling off ofthe wall facade

Basic damage ratio: 50%
Damage level:3

Basic damage ratio: 75%
Damage level:4c) Long crack and medium peeling offof the wall facaded) Peeling off of greater part of theexterior wall損傷面積の考え方
facade

④
② ③
①

⑩

⑥

Basic damage ratio: 100%
Damage level: 5e) Peeling off of almost the whole wall
facade

⑤ ⑦ ⑧

⑪

⑫

⑯

⑬

⑭

⑱
⑰

⑲

⑳

⑨ ⑮

f) Method of decomposition of thedamaged wall to calculate thedamaged area

Figure 3 Typical damage levels of walls
The damage ratio calculation has four steps: evaluation of basic damage ratio,
calculation of damage ratio, calculation of sub total damage ratio and total
damage ratio. The basic damage ratio is evaluated based on the damage level. The
damage ratio is the value which is multiplied by basic damage level and damage
area for each element, directions and damaged level as in equation (1). The sub
total damaged ratio is calculated by summation of damage ratio for each elementand directions as in equation (2). Finally, the total damage ratio is the value
multiplied by sub total damage level and coefficient for each element as equation
(3).

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�

�

�

���� = � � �������� � ����� �
�=1 � =1 �=1������� = � ������ �
�=1 � =1���� = ������� � ������������ �

(1)
(2)
(3)

�=1

i:Element, j:Direction, k:Damage level���� : Damage ratio where i,j , ������ : Basic damage ratio where i,j,k���� � : Damaged area where i,j,k , ����� :Sub total damage ratio where i��� :Total damage ratio, ������������ : Element coefficient
2.2 DEVELOPMENT OF PHOTO UPLOAD SYSTEM
Here, the prototype of “Photo upload system in the damaged area” was developed.
Photos of a damaged house are taken by residents or volunteer fire corps in thedamaged area and uploaded to the server. This system was developed for mobile
phones based on Android operating system which is installed in almost all thesmart phones except iPhone. The photo upload application should be installed oneach Android smart phone by the users who are residents or volunteer fire corps inthe damaged area.
Flow of the photo upload system is shown in figure 4. Firstly, residents or
volunteer fire corps as users input the basic information such as GPS information,
address and owner name. Secondly, they upload some photos such as overview ofthe damaged house, inclination of the damaged house and the damaged point ofroofs, walls and foundations. Finally, they confirm the input data and some photos.
Transition of the screen
start

Upload and confirm contents
Confirm the GPS information, zip
code, address, owner name, phone
number, etc.

Step 1

Basic information screen

Step 2

Photo upload main screen

Confirm the inspection site, houseand GIS data.

Step 3

Overview photo screen

Take and upload the photos ofdamaged house such as over viewphoto.

Step 4

Incline screen

Take and upload the photos ofinclineStep 5

Building element screen

Take and upload the photos of roofs,
walls and fundamentals

Step 6

Damaged point screen

Take and upload the photos of roofs,
walls and fundamentals

Step 7

Relationship screen

The damaged point photo is related
to the overview photo.

Step 8

Final comment screen

Input the comments which are
special situation of damaged house,consideration and so on.

end screen

Figure 4 Flow of photo upload system
Method of completing photo upload in the damaged area using upload application
is as follows: The users take some full view photos of a damaged house (entrance
Study on applicabilityof remotebuilding
damage systemassessment
system for large-scale
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damageassessment
for large-scale
earthquake
disasters
Focused
on
the
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October
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Vietnamside, opposite side of the entrance, left side of the entrance and right side of theentrance) and close-up view photos of the damaged points.
Figures 4 and 5 are the prototype system for primary inspection. After taking
photos of a damaged house, residents or volunteer fire corps select some photos
for uploading to each factor page. They should take pictures of the damaged houseconcerning three factors: overview, building inclination and building elements(roof, exterior walls and foundation). Further, they should relate the close-up
views of the damaged points to the full views using touch screen functions. The
red circle in prototype system shows damaged point which is related to overview
photo. After taking some pictures, users need to upload them to an exclusive
server in cloud condition using the upload application. Using this application
makes it easier to select and upload photos which are taken by the users in thedamaged area as smart phone has touch screen functions such as tap, drag, flick
and pinch out/in operations.
The
entranceside

The right
side of theentrance

The leftside of theentrance

The opposite
side of theentrance

Red circle shows damaged
point which is related toover view photo

Over view photo
Check mark ofmajor damage

Photo ofdamaged point

Upload button

Back button

Figure 5 Photo upload systemin the damaged area (wall upload)

Save button

Clear button

Figure 6 Photo upload systemin the damaged area (relationship)

Table 1 shows number of photos to be taken for remote assessment. The users
take some pictures of damaged building such as overview photos, incline photos
and close-up photos of damaged points. The overview and incline need 4 photos
respectively. The close-up photos of damaged points depend on the number of662

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damaged points of the building. Total number of required photos amounts to thesum of 4 overview photos, 4 incline photos and close-up photos of damaged
points.
Table 1 Number of photos for remote assessment

Part
Overview photo
Incline photo

Points of taking picture
Four directions
Four directions
Close-up photo
Roof*Number of damaged point
Close-up photo
Element
Wall*Number of damaged point
Close-up photo
Fundamental*Number of damaged point
Total number of photos

Number of photos
Total 4 photos
Total 4 photosܰ‫݂݋݋ݎ‬ܰ‫݈݈ܽݓ‬݂ܰ‫ ݀݊ݑ‬Ǥܰ‫ ݂݋݋ݎ‬+ ܰ‫ ݈݈ܽݓ‬+ ݂ܰ‫ ݀݊ݑ‬Ǥ +8

3. TRIALS OF PHOTO UPLOAD SYSTEM
3.1 EXAMPLE OF PHOTOS UPLOADED BY PHOTO UPLOAD SYSTEM
The authors tried to use photo upload system in Sendai city, Miyagi prefecture
suffered from the 2011 off the Pacific coast of Tohoku Earthquake, on March 26,
2013. Some damaged houses are still remaining in Sendai city without repair, and
10 of the damaged buildings were selected as the sample. Figures 7 and 8 are theexample of overview photos of damaged houses that are classified to be major
damage, major moderate damage, moderate damage and minor damage,respectively. These photos implies that identification of major or moderate
damage based on overview photos of a house is reratively easier compared withthat of small damage. This suggests that additional close-up photos of damaged
parts were especially important in case of small damage in order to achive thedamage assessment accurately.

a) Major damageb) Major moderate damage
Figure 7 Overview photos of damaged houses (1)Study on applicabilityof remotebuilding
damage systemassessment
system for large-scale
Study on applicabilityof remote building
damageassessment
for large-scale
earthquake
disasters
Focused
on
the
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October
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Vietnamc) Moderate damaged) Minor damage
Figure 8 Overview photos of damaged houses (2)3.2 CONFIRMATION OF DAMAGE FROM PHOTOS
Figure 9 is four overview photos of a house classified as minor damage. These
photos were taken from the four different directions. This house suffered fromsome damages due to the strong ground motions on b) the right side of theentrance and d) the left side of the entrance. However, these damages cannot be
confirmed from the overview photo due to the limitation of photo resolution.
Damages such as small cracks or peel off from the wall were difficult to be
identified only by overview photos. In addition, these photos show that things
surrounding a house such as plants, stone wall, etc. can be obstacles of the photos
for assessment. Climate conditions such as too much sunlight or shadow mightalso reduce the quality of the photos for assessment. In these cases, close-up
photos of the damaged points are especially important for accurate assessment. In
our developed photo upload system, a function for users to add some commentswith a photo was attached in case the photos don’t have enough quality due tothese reasons.

a) The entrance sideb) The right side of the entrancec) The opposite side of the entrance sided) The left side of the entrance
Figure 9 Four overview photos of a minor damage house

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Figure 10 is the example of photos of both overview and close-up. By using
additional close-up photos of damaged points, it become possible to identify thesmall damages of damage level 1 or level 2 such as small cracks and peel off fromthe wall. These photos are the example taken by a smart phone camera with theresolution of 1MB pixels. It was verified that both the overview photos andadditional close-up photos are essential to enhance the accuracy of the assessment
especially in case of small damage houses.
Close-up
photo
玄関右側

Overview photo
Close-up photo

Damage level:2
Damage level:2

Close-up photo

Damage level:1a) The right side of the entrance
Overview photo
Close-up photo

Damage level:1
Close-up photo

Damage level:1

Close-up photo

Damage level:1b) The opposite side of the entrance side
Figure 10 Photos of the some damages related to overview photos
According to the authors' verifications in previous research, the small damage
such as cracks and peel off from the wall can be confirmed from photo which hasover 1MB pixels. This photo upload system can change the resolution to 1MB
pixels automatically. If the file size of a photo is very large, the photo taken by
photo upload system cannot upload to cloud server due to the 3G/LTE line
capacity. That point was also confirmed through this trial of photo upload systemin the damaged area.

Study on applicabilityof remotebuilding
damage systemassessment
system for large-scale
Study on applicabilityof remote building
damageassessment
for large-scale
earthquake
disasters
Focused
on
the
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4. CONCLUSIONSIn this research, developed photo upload system as a part of remote building
damage assessment system was used for trial in order to verify its applicability to
the actual assessment. It became clear that big damage such as major damage andmajor moderate damage can be confirmed using overview photos. On the other
hand, small damages such as minor damage might be difficult to be confirmed
using only overview photos. In these cases, close-up photos of the damage points
are necessary to identify the small damages accurately. From the trial, it wasverified that damaged points of small damage with damage level 1 or 2 such as
cracks and peel off from the wall can be confirmed from photo which has over
1MB pixels. However, in the actual damaged area, there might be many obstacles
surroundings a damaged house such as plants, stone wall, etc, which reduce thequality of photos for assessment. Climate conditions such as too much sunlight or
shadow can be another obstacles. Then, small damage in moderate damage andminor damage cannot be confirmed using overview photos. In our developed
photo upload system, a function for users to add some comments with a photo was
attached. In these cases, comments at taking photos can help the understandings ofthe photos of damaged houses. The education and training of these techniques tothe users of photo upload system is essential.
As future study, we plan to conduct more practical operation tests with some local
government staffs to evaluate the effectiveness of both photo upload system andremote assessment system using photos taken in the damaged area.
REFERENCES
Tanaka, S., 2008, A Study on the Building Damage Assessment Processes for the2007 Niigata Chuetsu Oki Earthquake Disaster : Kashiwazaki Case Study ,Proceedings of social Safety Science No.22, pp.35-38
Fujiu, M., Ohara, M., Meguro, K., 2012, Development of remote building damage
assessment system during large-scale earthquake disaster, Proceedings of the
15th World Conference on Earthquake Engineering, CD-ROM, Lisbon, Portugal

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Safe and sustainable energy use in tall
residential buildings in Hanoi:
Practices and orientation
Thuy An PHAM1 and The Quan NGUYEN2
1
Undergraduate student in class of 54KT6,
National University of Civil Engineering, Vietnam
thuyanpham91@gmail.com
2
PhD, Vice Dean, Faculty of Construction Economics and Management,
National University of Civil Engineering, Vietnam
ABSTRACT
Hanoi is the city that has a highest rate of tall residential buildings at 16.64%
among the whole country. Currently, the press and media keep reporting on unsafe
cases in those tall residential buildings due to the use of different energy sources.
This research has been done in order to investigate the current use of energy types
provided in those tall buildings, the residents’ assessment of safety level of eachsource, the practice of safety equipment use, their perception on design standards
related to safety in energy provision system and the orientation of switching to newand more sustainable energy sources. The implications from the research results
can be useful for real estate developers in their development projects as well as for
Governmental authorities in issuing relevant policies, plans, standards, guidelines
for sustainable construction in general and the use of safe and sustainable sourcesof energy in tall buildings in particular.
Keywords: energy safety, tall residential buildings, apartment-buying decision,
safety protection facilities, sustainable energy
1. INTRODUCTION
Recently, residential buildings have proved to be an effective remedy for thecomplicated problem of providing accommodations for citizens in developing cities.
Residential buildings have quickly predominated the real estate markets in Hanoi inparticular and Vietnam in general. This type of accommodation helps authorities totake advantage of utilizing Hanoi’s urban area which have the highest population
density in Vietnam. According to the statistical figures issued by the Construction
Ministry, the nationwide proportion of residential buildings in urban areas only
accounts for 3.72 % of total living area and Hanoi have the highest residentialbuilding percentage (16.64 %), followed by Ho Chi Minh city, Hai Phong and Da
Nang (6.13%, 5.8%, 2.1 % respectively) (Linh Van 2011). Until 2012, there wereover 5000 multi-storey buildings including 927 over-nine-storey buildings in
Vietnam. All most all of the over-nine-storey buildings at the time were located in
major cities, such as Ho Chi Minh City (440 buildings), Hanoi (368 buildings), Hai
Phong (36 buildings), Quang Ninh (18 buildings), Thanh Hoa (13 buildings) (Lan667

October
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VietnamHuong 2012). As a result, more attention has been paid to the issue of safety related
to energy using for citizens in tall residential buildings due to a series of factors
such as structure quality, security and so forth. However, the number ofconflagration in residential buildings in Hanoi is rising to an alarming rate.
According to the Fire Protection Office, in the first 9 months in 2012 there were 15
fires in residential buildings nationwide (12 fires in Hanoi and the 3 others in Ho
Chi Minh City) with 1 case due to electric weld, 9 cases due to electricity problem
and 5 cases under investigation. Significant causes for fire are mainly associatedwith energy-supply issues created by unconformity in construction processes,
occupants’ lack of perception and sense of safety (Lan Huong 2012).
This paper looks into the practice of the utilize of safe and sustainable energy in tall
residential buildings in Hanoi in order to investigate the related issues such as safety
behavior and residents’ choice for sustainable energy sources, which may be ofinterest for real estate developers as well as urban management authorities in Hanoi.
2. RESEARCH METHODOLODY
The research is based on a survey using face-to-face interviews with 175
respondents, who engage in the decision-making of buying their apartments. The
survey respondents are selected across a spectrum of major districts of Hanoi
including Hoang Mai, Hai Ba Trung, Cau Giay, Ha Dong, and Dong Da districts
with convenient sampling method. They are at different age groups, educationlevels and levels of household income. Then, data collected was coded andanalyzed with SPSS software. Table 1 below presents the survey sample in terms ofage group, education and household income.
Table 1. Classifications of the survey participants
No
1
1.1
1.2
1.3
1.4
1.5
2
2.1
2.2
2.3
2.4
3
3.1
3.2

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Classification criteriaAge20-30 years
30-50 years
50-70 years>70 years
Not answer
Education level
High school
University/ college degree
Postgraduate degree
OthersMonthly household income
5-10 mil
10-20 milNumber

%

54
79
21
3
18

30.86
45.14
12.00
1.71
10.29

10
120
38
7

5.72
68.57
21.71
4.00

46
75

26.29
42.86

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No
3.3
3.4
3.5

Classification criteria
20-30 mil
>40 mil
Not answer
Total

Number
28
9
17
175

%
16.00
5.14
9.71
100

As can be seen from the table, a large majority of survey respondents are 30-50
years old, accounting for 45.14%, and the proportion of people aged 20-30 is
30.86% whilst the percentage of the over-fifty-year-old respondents is 13.71% ….
The number of graduates with at least one university qualification constitutes
approximately 90.28 %. The figures reveals that tall building residents who aredecision-makers in buying houses are mostly young and middle-aged with higheducation level. Nevertheless, income of a typical household is just above theaverage level of the country; nearly half of interviewed households earn 10-20
million VND per month. The average number of family members in a household isaround 3.5 people, which means that each person is provided about 19.529 m2 forliving.
3. DATA ANALYSIS AND DISCUSSIONS
3.1. The sources of energy used in tall buildings and their safety levels
It can be seen from the survey figures that every apartment is using energy fromnational electricity network. In detail, nearly two-thirds (61.7%) of the households
use gas cylinders whereas the proportion of central gas system and solar energy aresmaller, at 17.5% and 1.9% respectively. Meanwhile, 97.8 % of total households
admitted that electricity is the major energy taking the highest power expenditure.
Grid electricity predominates a powerful role in the total consumption, making ahuge the demand for electricity in the city. It is predicted that the energy demand
within the period of 2001 to 2020, with the average GDP of 7.1-7.2%-GDP growth,is 201 billion kWh and the demand in 2030 is estimated to reach 327 billion kWh.
Whereas, maximum domestic energy supply is estimated to be at 165 billion kWh
in 2020 and 208 billion kWh in 2030, leading to the shortage of 119 billion kWh(Minh Hanh 2006).
In order to measure the safety level of each source of energy, the survey
respondents have been asked to score each source from 1 (the least safe) to 5 (themost safe). Sources of energy that have been included in the survey are gridelectricity, gas vessels (cylinders), centre gas system, solar energy and nuclear
energy. Table 2 presents the results generated from the respondents assessments
using SPSS.

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Table 2. Respondents’ assessments on safety level of each source of energy

N
Mean

Valid
Missing

Safe assessment for type of energy
Grid
Gas
Center gas
electricity
cylinderssystem
160
160
156
15
15
19
3,72
2,49
2,95

Solar

Nuclear

155
20
4,17

154
21
2,10

Solar energy has the highest score (4.168) which means it is considered as the safest
source of energy. Electricity ranks second with 3.719, preceding central gas system
and gas cylinders (2.949 and 2.488 respectively) and nuclear energy has the lowest
credibility (2.097). It seems that the survey respondents less trust on nuclear energy
since the media keeps reporting about accidents with nuclear power plants on over
the world, such as Fukushima accident. According to the survey, evidently,
consumers favor solar energy most. Nevertheless, this type of energy is not popularin Hanoi in particular and in Vietnam in general.
3.2. The use of safety equipment and firefighting equipment in the surveyedapartments
The survey results reveal that approximate 60.3% of the respondents’ apartments
being bought in the post-construction stage. A certain number of apartments havebeen bought during the construction of the buildings (17.3%) or resold by aprevious owner (not the developer – 16.7%) (Table 3). Safety equipment inhouseholds, therefore, are inherited from the previous owners or provided by thedevelopers as in design documents.
Table 3. Classification of respondents’ apartment by purchasing timeNo

Time of purchasing

Number of apartment

Percentage (%)

1
2
3
4
5

Before construction stage
In the construction stage
Post-construction stage
Buying from previous owner
Not answer
Total

9
27
94
26
19
175

5.14
15.43
53.71
14.86
10.86
100%

The survey data point out that over a quarter (28.6 %) of the total participatedhouseholds do not use any safety devices (like automatic fuse, gas-leaking alarm,smoke alarm), and the rest have installed at least one. Among the one that selfequipped safety devices, 27.5 % of households installed only one device, roughly
38.5 % of them have fixed over two fixtures and there are only 5.5 % having
installed more than 3 safety devices.

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In comparison to the use of safety devices in the participants’ apartments,
firefighting equipment (fire extinguishers) is more concerned by the majority ofhouseholds, with up to 64.5% of apartments are fully equipped. Among thehouseholds’ flats in the survey that have not been equipped with fire extinguisher
devices, only 6.5% of the respondents don not have any intention of installing
firefighting equipment while 23.7% of them do. As can be seen from the results
above, there is an increasing awareness of safety among residents in terms of using
energy sources in their apartments.
In order to analyze the effect of safety equipment in the buying decision of
respondents for apartments, respondents were asked if they agreed to buy anapartment without their desired energy sources, yet the apartments were equippedwith safety equipment. Up to 52.2 % respondents accept the apartment; 36.9% ofthem show a hesitation and only 10.8% of them refuse to buy since they doubt theequipment quality. Based on the above results, it can be concluded that safety
devices in tall residential buildings catch customers’ attention. Nonetheless, safety
equipment provided in Hanoi market must be examined thoroughly, since they are
not completely reliable (Bao Linh 2011).
3.3. Tall residential building citizens’ knowledge about standards for designand construction of energy supply and firefighting system in residentialbuildings
When considering buying an apartment, up to 57 % of residents who participated in
the survey pay no attention to the energy sources provided with the apartment; only
20.4% of them examine this issue. The survey results show that the energy sources
provided with apartments do not influence the buying decision of a majority of
respondents. There are 25 % of them do not pay attention to this factor when they
can balance different factors such as price, convenience, area of the apartment.
42,4% of the participated citizens think that this factor only accounts for nearly 20%of their decision of choosing to buy a flat. Consequently, the survey part on theawareness of construction and design standards of energy provision system havebrought up similar information. There are 57.2 % of citizens living in the surveyedapartments are not aware of these standards, 30.2% of them only know about their
existence and there is only 11.9% of them knowing the contents while just 0,6% ofthem can understand the standards thoroughly. With an alarming of awareness ofthe standards like that, it is necessary to raise more attention of the tall residentialbuildings citizens on this issue.
In practice, a wide range of legal documents relevant to the issue have been
published. The most important regulations include Decree 169/2003/NĐ-CP about
electricity safety which indicates standards in generation, transferring and using
electricity; Decision 51/2008/QD-BCT decision issued national technicalregulations on safety in the storage, transport, use and disposal of industrial
explosives; Vietnam Standard TCVN 6160 - 1996 - Fire Fighting building - Design
requirements: This standard specifies the basic requirements for fire protection(PCCC) when designing new construction, renovation and expansion of the houses,
tall residential buildings; Vietnam Regulation QCVN 06: 2010/BXD by theInstitute for Construction Science and Technology compiled, Department of
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Science, Technology and Environment browsers, the Ministry of Construction
issued Circular No. 07/28 2010/TT-BXD in 7/2010 - National Technical Regulation
on fire safety for houses and works; system of national standards for electricalsafety as TCVN 7441 - LPG supply system in consumption - Requires design,
installation and operation..... These have become guidelines for the designers anddevelopers of tall buildings to do their development job, but have not beenpromoted enough to become popular to the potential residents.
3.4. Tall building residents’ perspective on future sustainable energy sources
When being asked about their choice on future sustainable energy sources,
participants came up with a wide range of ideas. Figure 1 shows the research resultson the choice of the survey respondents in terms of future sustainable energy
sources.

Figure 1. Choice for future sustainable energy sources
The data shows that electricity is still the most selected source of energy, even in
the future. This fact raises the need of more investment into this type of powersource.
Investigating residents’ concern over sustainable energy, it is observed that only
2.5% of the survey respondents find it unnecessary but nearly a half (44.6%) ofthem will decide to switch on to the new source but need to make priceconsideration. The rest (52.9%) completely support new energy sources which aresafe and environment-friendly. This fact indicate a good sign for investor inapplication of sustainable and renewable energy. On the other hand, installation andoperation cost is an issue of broad concern.
The correlation between age and the concern for new energy source was tested withSPSS with testing results presented in Table 4. Age and the concern are supposedly
not mutually related. After analyzing the collected data, the results are represented
in the following table:

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Table 4. Chi-Square Tests for the correlation between age
and concern for new energy source
Chi-Square Tests
Value
df
Asymp. Sig. (2-sided)
Pearson Chi-Square
5.899a2.052
Likelihood Ratio
6.328
2
.042
Linear-by-Linear Association 2.431
1.119
N of Valid Cases
166
a. 0 cells (,0%) have expected count less than 5. The minimum expected
count is 10,41.
Based on the calculation results, Sig = 5.2% <Pearson Chi-square = 5.899% toreject the initial assumption. It is then can be concluded that age and concern for
new energy source have an interactive relationship with each other. To proceed tolearn more about this relationship, an additional test was conducted. The symmetricmeasures are presented in Table 5.
Table 5. Symmetric Measures Results
Symmetric Measures
Value Asymp. Std. Errora Approx. Tb Approx. Sig.
Ordinal by Ordinal Gamma -.190.131-1.424.154
N of Valid Cases
166
a. Not assuming the null hypothesis.
b. Using the asymptotic standard error assuming the null hypothesis.
It is noticed that the two quantities have an inverse correlation, which means
residents having higher age have less desire to change the current energy sources
than young people. However, due to limited number of samples, this relationshipcannot be validated accurately.
4. CONCLUSIONS
The results of survey illustrates that grid electricity is the most popular energy
resource used in the investigated household, but the solar energy is evaluated as thesafest source of energy. This has contributed to the raising need of the country inmore investment for this type of power. Residents of the tall residential building,especially the ones from young intellectual class, have increasingly consideredsafety issues as important in the use of energy sources. However, due to solar andother sustainable energy sources are not popularly used, citizens are timid in
deciding to switch to these sustainable energy sources.

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The survey respondents often purchase apartments when they have been notequipped with adequate safety facilities to guarantee their families’ safety in usingof energy whilst the fire safety equipment are more concerned. This is because of anenhancement in the society's perception of the risk of fire due to news and reportsby the mass media and the availability of this type of equipment and their ease of
installation in comparison to safety devices which must be installed during
construction time. Nevertheless, still people are not really aware of their rights
related to safety when buying apartments, since very few people in the survey knowor care to the design standards related to safety of energy supply for tall buildings.
Since people in Vietnam in general and Hanoi in particular have raised interest in
saving energy and developing sustainable sources of energy, as well as the risingawareness of city dwellers in sustainable development and the needs of sustainablebuildings such as the ones that meet LOTUS standards, real estate developers needto pay more attention on alternatives of sustainable sources of energy to be used intheir projects. Though some of them still think of the cost they have to bear whenswitching to a new source of energy that is more sustainable, most of the tallbuilding residents in the research are ready to switch to a new and more sustainableenergy source. The Government, however should be aware of this issue indeveloping plans and policies on sustainable construction in general and standards
and guidelines for sustainable energy use in buildings in particular.
REFERENCES
Bao Linh (2011) Gas leaking sensor: Safe or unsafe?. An Ninh Thu Do Newspaper
OnlineLan Huong (2012) Hanoi takes the lead in quantity of fire in tall buildings. Dan Tri
OnlineLinh Van (2011). Hanoi become a champion in terms of tall buildings. Dien Dan
Doanh Nghiep Online Newspaper.
Minh Hanh (2006) One solution for the problem of electricity insufficiency. Dang
Cong San Vietnam Online

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Development of simulation exercise
for emergency response headquarters
focused on management by objectives
Shinya KONDO1, Akiyuki KAWASAKI2, Miho OHARA3, Akira KODAKA4and Adisorn SUNTHARARUK4
1
Chief Researcher, Disaster Reduction and Human Renovation Institution, Japankondo2@dri.ne.jp
2
Project Associate Professor, ICUS, IIS, The University of Tokyo, Japan
3
Associate Professor, ICUS, IIS, The University of Tokyo, Japan
4
Loei Fund for Nature Conservation and Sustainable Development, Thailand
ABSTRACT
Our research group hopes to propose a disaster information system for improving local
communities’ disaster response ability in rural and agricultural mountainous areas where support
from the national and local governments cannot be expected. A disaster information dissemination
system is based on lessons and knowledge of disaster management accumulated in Japan, and thissystem is localized according to needs and current situation of each country.
Thailand has disaster risks everywhere in the country, including drought, flood, and landslide in
the northeast, cyclone in the northwest, tsunami in the south coastal area, and flood in Bangkok city.
The fast and wide transmission of disaster information by communications infrastructure isimportant for implementation of disaster mitigation measures. In the northeast, the economy has
lagged behind compared with other regions, people become migrants in urban areas such as
Bangkok, and education level is generally low. In such areas, it is considered that people could notuse disaster information effectively, even if they can get disaster information.
In this paper, the authors organized the reality and problems of disaster information dissemination
system in Loei province (Thailand) from the perspective of “planning and output of disaster
information”, “disaster information generation flow” and “disaster information distribution flow”.
Furthermore, issues and improvements of disaster information dissemination systems in Loei
province were revealed in comparison with the case of disaster management for typhoon Talas ofthree municipalities in the southern part of Wakayama Prefecture from the view point of“multiplexing communication network” and “early evacuation before dark”.
Keywords: disaster information dissemination system, flood disaster, sediment disaster,
localization, area-mail, rural and agricultural mountainous area675

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676

New Technologies for Urban Safety of Mega Cities in AsiaComparing benefits of hydropower development in twoboundary systems in the MekongaSeemanta Sharma BHAGABATIa, Akiyuki KAWASAKIa,bRegional Network Office for Urban Safety, Asian Institute of Technology, Thailand.
E-mail: seemanta0605@gmail.combInstitute of Industrial Sciences, The University of Tokyo, Japan

ABSTRACT
Hydropower dam development, although is a very promising source of energy, has enormous
economic, environmental, and social impacts at a local, national, and trans-national level which
may result to transboundary conflicts among the riparian countries. Past literature has suggested
that the conflicts arising from hydropower development may be approached through benefit sharing.
Selecting different sets of riparians (such as countries (Political boundary) and river sub-basins(Natural boundary)) within the same study area may lead to different benefit sharing system. Whilea lot of research has been done in the country aspect (political boundary), the natural boundary
aspect has been left simply untouched. This study shows promising results of the natural boundary
approach. The study attempts to investigate the difference in benefit sharing in the transboundary
sub-basin, the Sekong, Sesan and Srepok (commonly known as 3S) sub basin, covering areas ofLaos, Cambodia and Vietnam in the Mekong River Basin using a game theory approach. Two setsare defined, based on Political boundary (National boundaries) and based on Natural boundary(3S boundaries). A wide range of parameters such as energy production, irrigational benefits, flood
control socio-economic costs etc. have been incorporated to define models and methodologies. This
study then compares these two sets using the game theory concepts, such as core stability andincentive compatibility. Here we show that depending on the type of riparians chosen, the extent ofbenefit sharing changes. The results of the study will provide a basis for local policy decisions andregional planning in the Mekong River and beyond.
Keywords: Mekong River Basin, 3S sub-basin, Hydropower development, Game Theory, Natural
boundary, Political boundary, Optimization




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Optimization the use of rice husk ash to increase
bearing capacity of difficult soil foundation for low
cost housing in Semarang’s Urban areas.
Silvia Fransisca Herina
Senior researcher
Research Institute for Human Settlements,
Ministry of Public Works, Indonesia
silvia_herina@yahoo.com
ABSTRACTFor any kind of Urban areas the need of housing is one of the important aspects. Often theimbalance in between high buildings demand and limited land trigger an increasing of land
prices followed by the driving up of the using of unstable soils as ground foundation. For highrise building that condition is not a problem, because they will selecting foundation’s type thatis safe, but for low cost housing, the selection of a more secure foundation ,deep foundation for
example, lead to more expensive consequences, and this is a constraint, because the foundation
could be much more expensive than the building’s cost.
Rice husk ash which had been a waste materials, content fairly high SiO2 (55 to 58%) which isone of the chemical elements essential in the formation of cement, if SiO2 mixed with lime (CaO)
would produce a product cementation . Optimization of the composition of a mixture of local
sand and in situ soil result in concreting effect which possible to increase bearing capacity ofthe soil, so that simple shallow foundations can be used to support building on it.
In addition to economic considerations, this research also consider the issue of environment
friendly by reducing material waste. The case project is the ground foundation of low cost
housing in expansive soils in Semarang, center of Java.

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Scale effects on the shear strength of waste
in coastal landfill sites
Nguyen Chau LAN1, Toru INUI2, Kazuki IKEDA3
and TakeshiKATSUMI4
1
PhD, Faculty of Civil Engineering, University of Transport andCommunications, Vietnam
nguyenlan1981@gmail.com
2
Associate Professor, Gradual School of Global Environmental Studies, Kyoto
University, Japan
3
Former Graduate Student, Faculty of Engineering, Kyoto University, Japan.
4
Professor, Gradual School of Global Environmental Studies, Kyoto University,
Japan

ABSTRACTIn Japan, a significant volume of municipal solid waste incinerator ash (MSWIA),
slag and soil are disposed in coastal landfill sites located in Tokyo and Osaka bay.
Future reclamation of these final disposal sites is an important goal. Thus, it isrelevant to understand the shear strength properties of the waste layers in coastal
landfill sites to utilize the land after closure. However, the particle size
distribution of the waste ranges from fine-grained to coarse-grained (gravel,
glass, etc.) affecting the estimation of the shear strength properties of the waste
sample in coastal landfill sites. There is no available research on the effects ofoversize particle on the shear strength of waste samples in coastal landfill sites.
Therefore, this paper presents the results of larger triaxial test (150 mm x 300mm) for waste samples. In the large triaxial test, the pore water pressure
generated is higher compared to the results obtained for small samples due to thelonger dissipation time of pore water pressure. The smaller values of shear
strength for large samples are also related to the crushability of large particle
size. Thus, the frictional angle of large specimens is slightly smaller than that ofsmall ones. Moreover, to calculate the stability of coastal landfill sites, if thestrength parameters results from large triaxial test are used, the safety factor
might decrease due to the lower of friction angle of large triaxial test and it would
be more precise compared to the value obtained from a small triaxial test.
Keywords: waste, ash, coastal landfill, large triaxial test, mechanical properties

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Vietnam

1. INTRODUCTION
In Japan, a significant volume of municipal solid waste incinerator ash (MSWIA),
slag and soil are disposed in coastal landfill sites located in Tokyo and Osaka bay.
Future reclamation of these final disposal sites is an important goal. Thus, it isrelevant to understand the strength properties of the waste mixture layers incoastal landfill sites to utilize the land after closure. However, the particle size
distribution of the waste mixture ranges from fine-grained to coarse-grained(gravel, glass, etc.) affecting the estimation of the strength properties of the waste
mixture sample in coastal landfill sites. Generally, the strength properties of asample material is investigated by a triaxial test. When triaxial tests are run, themaximum particle size of the samples must be less than one-sixth of the diameterof the specimen. Therefore the standard triaxial test, with a specimen of 50 mm indiameter, cannot be used if the diameter of the waste mixture sample is larger than
9.5 mm. Numerous research studies have attempted to increase the maximum
particle size of the specimens tested by increasing the size of the testing apparatus
in order to accurately measured the mechanical behavior of geomaterials (Hennes,
1952; Holtz & J., 1956). Previous studies have investigated the effect of large
particles on shear strength of soil by using large triaxial test and reported that theincrease in gravel content decreases the density and shear strength of the material(R. Fragaszy, Su, & Siddiqi, 1990; R. J. Fragaszy, Su, Siddiqi, & Ho, 1992).
Kirkpatrick (1965) studied the Leighton Buzzard sand with uniform particle sizes
using triaxial tests; the results showed a reduction in friction angle as the mean
particle size increased while the porosity was kept constant. However, otherresearchers concluded that the shear strength of mixture (soil and gravel) increases
with gravel content.
Direct shear test is another method that can be utilized to determine the shear
strength. Hennes (1952) and Simoni and Houlsby (2006) used this method to test
sand and gravel samples; the results showed that the addition of gravel to the
mixture causes an increase in friction angle. However, Cerato and Lutenegger(2006) studied the scale effect of direct shear tests on sands and observed adecreased in friction angle when the maximum particle size increased. Their study
showed that the friction angle measured by direct shear testing depends on sample
size and that the influence of sample size is also a function of sand type andrelative density. They concluded that for dense sand, the friction angle measured
by direct shear tests is reduced as the box size increases at a ratio of at least 1:50
between box width and particle size.
However, there is no available research on the effects of large particle on the shear
strength of waste mixture samples in coastal landfill sites. Therefore, in thisresearch, large-scale (150 mm x 300 mm) and small-scale (50 mm x 100 mm)
triaxial tests were carried out on waste mixture samples to study the effect ofspecimen size on the shear strength of the samples. This paper deals with theeffects of particle size and confining pressure on the shear strength of waste
mixture samples.

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2. MATERIAL AND METHODS
2.1. Material
The waste samples and the simulated water in coastal landfill site employed inthis study were obtained from the coastal landfill site in Osaka Prefecture. The
waste samples were collected before being disposed at the coastal landfill site.
Approximately 200 kg of wet waste sample include incinerator ash; slag andsurplus soil, etc. were collected and then dried in a room with an averagetemperature of 20oC. For conducting small specimen, large pieces such as glasses
or rocks were removed and the sample was sieved with 9.5mm opening sieve andset aside until use. For large specimen, all large pieces were used except pieces
larger than19mm. The maximum diameter of waste mixture for small and large
triaxial test is 9.5mm and 19 mm, respectively. Figure 1 shows the particle size
distribution for small and large samples, determined according to JIS A1204. The
specific gravity of the waste sample was 2.67.

100

Percentage of finer (%)

80

60

40

20

0
1E-3

Large sample
Small sample
0.01

0.1

1

10

100

Particle size distribution (mm)Figure 1: Particle size distribution of waste mixture samples
for small and large triaxial tests
X-ray florescence Spectroscopy (XRF) was performed to determine the chemicalcomposition of the waste samples. The chemical composition of the sample isshown in Table 1. The main components of the sample are CaO; Fe2O3 and SiO2.
The XRF shows that lime (CaO) is the main component of the sample (51.6 %).
Table 1 Chemical composition of waste sample (%)
CaO
51.6
1

Fe2O

SiO

Al2O

TiO

3

2

3

2

20.40

9.11

4.28

3.30

SO3

K2
O

Zn
O

Cr2O
3

Mn
O

Cu
O

2.7
7

1.66

1.87

1.57

0.54

0.52

Scale effects Scaleon theeffects
shear onstrengthof wastein coastal
siteslandfill sites
the shearstrengthof wastelandfill
in coastal

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2.2. Methods
In this study, small specimens were prepared by compacting 5 layers of waste in
to a split cylindrical mold (50 mm diameter and 100 mm in height) 80% of
maximum dry density (1.28 g/cm3) with optimum water content of 34.5%
according to the value obtained from the Standard Proctor Compaction Test.
For large CU triaxial test, specimens were prepared by compacting 5 layers ofwaste mixture in to a split cylindrical mold (150 mm diameter and 300 mm inheight) with the same maximum dry density and optimum water content as small
specimens. In this test, D/dmax= 15/1.9= 7.89 (where D is diameter of specimen inlarge triaxial test and dmax is the maximum particle size of waste mixture).
Small and large CU triaxial tests were carried out on waste mixture specimens
following the same procedure. These specimens were saturated by applying avacuum procedure (Rad & Clough, 1984) to keep a constant confining pressure of
20 kPa. After reaching the final step (-70 kPa for cell pressure and -90 kPa forsample pressure) de-aired water was circulated into the specimen for 3 hours andthen sample pressure and cell pressure were reduced to -20 kPa and 0 kPa
respectively. Back pressure was increased step by step until it reached 240 kPa
and cell pressure was 220 kPa. After that, pore pressure coefficient (B-value) was
checked to have B-values larger than 0.95 and ensure that samples were fully
saturated. The samples were consolidated with an effective confining pressure of50, 100 and 150 kPa and sheared at a constant strain rate of 0.5%/min until 15%
of axial strain was reached.
The target of conducting small and large samples in triaxial test is to consider theeffect specimen size on shear strength of waste mixture is considered. It is crucial
to estimate the shear strength of waste mixture in coastal landfill sites for future
land utilization. The initial conditions for large and small triaxial test are shown in
Table 2.
Table 2: Initial condition of waste mixture samples
Type ofTriaxial
test

Confiningpressure(kPa )

Dry density
after
consolidated(g/cm3 )Void ratio e(afterconsolidated )

B
value

For
small
triaxial
test

50

1.02

1.62

0.95

100

1.02

1.62

0.95

150

1.02

1.62

0.95

50

1.02

1.61

0.95

100

1.03

1.56

0.95

150

1.06

1.53

0.95

For large
triaxial
test

684

Dmax
(mm)

9.5

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3. RESULT AND DISCUSSION
3.1. CU test for small triaxial test
Figure 2 shows the stress-strain curves for small samples. Generally, the deviator
stress increases dramatically from 0 to 2 % of axial strain and reaches a peak after
6% of axial strain. After that the deviator stress reaches a constant value until 15%
of axial strain. The stress-strain curves illustrate the strain hardening
behavior of waste mixture samples.

400

Deviator stress (kPa)

300

200

50 kPa100

 100 kPa

150 kPa

0
0

2

4

6

8

10

12

14

16

Axial strain(%)

Figure 2: Stress-strain curves for small samples
Figure 3 shows the pore pressure results versus axial strain. For samples under aconfining pressure of 50 kPa, the pore water pressure shows an increase trend at
the initial stage until it reached a peak value of about 20kPa and then it is reduced
steadily to nearly zero at 15% of axial strain. Pore water pressure generated insamples that sustained 100 kPa confining pressure, showed a similar trend thansamples under 50 kPa but reaching a pore pressure peak value of about 50 kPa
and then reducing steadily until reaching about 35 kPa. However, for samples
under 150 kPa, pore water pressure increases and reaches a peak at 2% and thenkeeps a constant value until an axial strain of 15% is reached. The samples under
initial conditions in small triaxial test showed a contractive behavior in shearing
process due to the positive value of the pore water pressure when the axial strain
increased from 0 to 15 %.

Scale effects Scaleon theeffects
shear onstrengthof wastein coastal
siteslandfill sites
the shearstrengthof wastelandfill
in coastal

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Vietnam100

Pore water pressure kPa)

80

60

40

50 kPa100 kPa
150 kPa)

20

0

0

2

4

6

8

10

12

14

16

Axial strain (%)

Figure 3: Pore pressure results versus axial strain for small triaxial test

400

Deviator stress (kPa)

300

200

50 kPa100 kPa
150 kPa

100

0
0

50

100

150

200

250

300

350

400

Axial strain(%)

Figure 4: Stress paths for small triaxial test
The deviator stress (q) and the mean effective stress (p’) are calculated byfollowing Eqs. (1) and (2):(1)
� � �� �� � � � �(2)�� � �� �� � �� � � )⁄3

where ’1 and ’3 are the effective axial and confining stress. Fig. 4 shows theeffective stress paths for samples in small triaxial test were plotted in a p’-q plane.
In this figure, from the beginning, stress paths showed an increase of porepressure with the stress path moving to the left until pore pressure reduces and theeffective pressure increases moving the stress path into the right direction.
3.2. CU test for larger triaxial test
Figure 5 shows the stress-strain curves for large samples. The deviator stress

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increases dramatically from origin to reach a peak value at about 2% of axial
strain. After that, the deviator stress decreases steadily until 15% of axial strain
and the stress-strain curves illustrate the strain softening behavior of waste
mixture samples. This behavior significantly change compare with the results forsmall samples.
Figure 6 shows the pore water pressure versus axial strain. For specimens thatsustained 100 and 150 kPa of confining pressure, the pore water pressure
increases dramatically from 0% to 2% of axial strain and from 2% to 15% it has amild but steady increases. In the case of specimen that sustained 50 kPa ofconfining pressure, pore water pressure has a constant value from 2% to about
15% axial strain.

Figure 5: Stress-strain curves for large samples

Figure 6: Pore pressure results versus axial strain for large triaxial test

Scale effects Scaleon theeffects
shear onstrengthof wastein coastal
siteslandfill sites
the shearstrengthof wastelandfill
in coastal

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2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 7: Stress paths for large triaxial test
Fig. 7 shows the effective stress paths for large triaxial test. In this figure it can beobserved that from the beginning, stress paths moves to the right until the deviator
stress reach a peak value and after that the deviator stress starts decreasing due toan increase in pore water pressure and moving the stress path into the right
direction.
.
3.3 Effect of particle size on shear strength of waste mixture sample
In order to compare the peak strength envelopes and the shear strength parameters
for large and small samples, the shear strength parameters are determined using alinear interpolation. Figure 8 shows the peak strength of small samples and large
samples. The shear strength parameters-cohesion intercept c’ and the angle offriction ’- associated with these peak strength envelopes can be obtained using
the following two equations:��(3)� � = ����� ������ � ����� � )�(4)
� = ��
�� ����� � )where M is the slope of peak strength envelope and f is the q-intercept of the peakstrength envelopes in p’-q stress space.

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Figure 8: Peak strength envelopes of small samples and large samples
The cohesion and angle of friction obtained are 0 kPa, 46.7 for small sample, and2.8 kPa, 44.78 for large sample, respectively. The direction of peak strength
envelope for samples and larger samples is similar. Thus, the strength parameters
results are almost no change. The most important reason for the change in shear
strength is related to pore water pressure generated. In the large sample, due tolarge diameter of mixture waste and large specimen the pore water pressure
generated are higher compare to those in small samples. The change in pore waterpressure contributed to the change in shear strength of large sample compare withsmall samples. Thus, most important reason for the change in shear strength isrelated to pore water pressure generated. In the large sample, due its the large
diameter, the pore water pressure generated is higher compare to the results
obtained for small samples. The change in pore water pressure contributed to theincreased in shear strength for large sample compare with small samples.
The differences in stress paths for small and large samples could be related to thecrushability of the larger samples. The crushability of larger samples wereobserved, although the initial of dry density for small and large samples are thesame but the void ratio were reduced in consolidated step for large samples
compared with small samples. These results showed that the volume of large
samples was reduced due to crushability. This behavior has been observed in aprevious research conducted by Kokusho (2004). The two major factors
governing the shear strength of granular materials are interlocking between
particles and particle breakage. The interlocking between particles increases theshearing resistance, while the breakage of particles decreases the shear strength. In
this test, the larger samples had larger breakage of particle and that lead to lower
shear strength compare with results obtained from small samples. The results ofthis study show that as the size of particles increase, the shear strength of waste
mixture decreases. These results are consistent with results presented by
Kirkpatrick (1965); Fragaszy et al. (1990) and Kokusho et al. (2004).

Scale effects Scaleon theeffects
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siteslandfill sites
the shearstrengthof wastelandfill
in coastal

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4. CONCLUSION
Based on the experimental results, the following summarizes about the scaleeffects of specimens on the mechanical properties of waste mixture in coastal
landfills:
1) In coastal landfill sites, the presence of large particles in waste mixture canchange the results of triaxial test. It is necessary to estimate the change ofshear strength if the waste mixture sample contains large particles. Thus, thecomparison between small and large triaxial test is necessary to understandbetter the shear strength behavior and pore water generated from waste
mixture samples. In this research, the particle size of the larger samples forlarge triaxial test 15cmx30cm is larger than 9.5mm. In the large triaxial test,
the pore water pressure generated is higher compared to the results obtained
for small samples due to the longer dissipation time of pore water pressure.
2) The value of shear strength obtained from the triaxial tests for large samples
are smaller than with the results obtained for small samples due to thedissipation of pore water pressure that affect stress paths and that in turn
reduce in the strength of large samples. The smaller of the shear strength forlarge samples are also related to the crushability of large particle size. Thus,
the frictional angle of large specimens is slightly smaller than that of small
ones. Therefore, in order to estimate the shear strength in the coastal landfill
sites, it is suggested that the large triaxial test should be conducted due tolarge particle size of sample collected from the sites (23% of particle size
larger than 9.5mm for the samples in Osaka coastal landfill sites). Moreover,for calculating the stability of coastal landfill sites, if we use the strengthparameters results from large triaxial test, the safety factor will be lower due
to the lower of friction angle of large triaxial test and it is more precise
compare to the value of the small triaxial test.
REFERENCE
Cerato, A. B., and Lutenegger, A. J., 2006. Specimen size and scale effects ofdirect shear box tests of sands. Geotechnical Testing Journal, 29(6), 507-516.
Fragaszy, R., Su, W., and Siddiqi, F., 1990. Effects of oversize particles on thedensity of clean granular soils. Geotechnical Testing Journal 13(2), 106-114.
Fragaszy, R. J., Su, J., Siddiqi, F. H., and Ho, C. L., 1992. Modeling strength of
sandy gravel. Journal of Geotechnical Engineering-ASCE, 118(6), 920-935.
Hennes, R. G., 1952. The strength of gravel in direct shear. ASTM special
technical publication, STP 131, 51-62.
Holtz, W. G., and J., G. H., 1956. Triaxial shear tests on pervious gravelly soils.
Journal of the Soil Mechanics and Foundation Division, 82, 1-22.
Kirkpatrick, W. M., 1965. Effect of grain size and grading on the shearing
behavior of granular materials. Paper presented at the Proceedings of the sixthInternational Conference on Soil Mechanics and Foundation Engineering.
Rad, N. S., and Clough, G. W., 1984. New procedure for saturating sandspecimens. Journal of Geotechnical Engineering-ASCE, 110(9), 1205-1218.
Simoni, A., and Houlsby, G. T., 2006. The direct shear strength and dilatancy ofsand-gravel mixtures. Geotechnical and Geological Engineering, 24(3), 523-549.

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Triaxial tests for elastic wave measurementwith associated matric suction on
unsaturated fine content sandy soil
1

Laxmi Prasad SUWAL1, Reiko KUWANO2, and Takeshi SATO3
Project Researcher, ICUS, Institute of Industrial Science, The University of Tokyo
Suwal@iis.u-tokyo.ac.jp
2
Associate Professor, Institute of Industrial Science, The University of Tokyo
kuwano@iis.u-tokyo.ac.jp
3Integrated Geotechnology Institute Ltd., Tokyo, Japantsato@iis.u-tokyo.ac.jp
ABSTRACT
Most of engineering infrastructures are constructed in shallow depth soil where
moisture contents are being varied due to natural phenomena as well as humanactivities. The ground inevitably possesses variation of matric suction; sandy soils
possess low suction in such shallow ground. In order to cope with the complex
behaviour of sandy soil, the materials properties with associated suction variation
are needed to evaluate. However there is still lacking of good tools for evaluating
material`s properties of sandy soils; consisting of various degree of saturation
with accounting matric suction and other elastic parameters. The triaxial
apparatus enabling to measure elastic waves and matric suction, mainly low
suction, was initially employed in this study. Triaxial tests were performed using
natural sand; Edosaki sand, containing fines in various degree of saturation to beacquainted with elastic properties of sandy soil possessing low suction. Improved
triaxial apparatus enabling to measure both elastic waves and matric suction was
adopted. A specimen was prepared by tamping method with (5% - 15%) initialmoisture content. The experiments were performed applying 50 kPa effective
isotropic stresses. The elastic waves were measured in several moisture contents
with monitoring the associated matric suction variation.
Keywords: Triaxial test, partially saturated soil, elastic wave, matric Suction

1. INTRODUCTION
Collapse of soil structures is generally known as the additional deformation within
the short time period. So collapse is believed to be responsible to damage or failof many kinds of infrastructures such as embankments, earthen dams, levee andbuildings resting on not well compacted soil etc. Collapsing behavior consists ofsaturation process of unsaturated meta-stable soil. So, the theory of unsaturated
soil is crucial for understanding this phenomenon. The mechanical behavior of aloosely deposited soil is strongly depends upon the amount of fines, volume massof soils properties such as void ratio (e), water content (w) and degree ofsaturation (Sr.) (Fredlund and Morgenstern1977). Most of the infrastructures are691

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamconstructed on shallow depth ground and the ground is generally composed bysandy soils like Edosaki sand. In this study, Edosaki sand was tested on thetriaxial apparatus to evaluate collapse potential and elastic properties inunsaturated condition.

2. MATERIAL AND APPARATUS
2.1 Edosaki sand
It is natural sand of containing fines collected from the Ibaraki prefecture, Japan.
Grains are mostly round with yellowish orange color. It is mostly used in earthen
infrastructures as filling materials in japan. The photograph taken from optical
microscope of the sample of Edosaki sand including gradation curve are shown in
Figure 1

Figure1 Edosaki sand and its gradation curve
2.2 Apparatus and Transducers
Small size, gear driven and strain controlled triaxial apparatus was used for
performing experiments. The axial loading system consists of an AC servomotor
and a reduction gear system, electro-magnetic clutches and brakes. Experiments
were precisely controlled by high speed computer. As shown in Figure 2, thespecimen and other accessories were set up. The upper and lower tanks with loadcell were hung to monitor the inflow and outflow of the water through thespecimen. Local Deformation Transducer (LDT) as per Goto (1991) was
employed for axial deformation of the specimen. A couple of LDT was attachedon surface of the specimen. Clip gauge was used for radial deformation (strain)measurement. Three clip gauges were attached on the specimen. Recently
developed technique for elastic wave measurement; disk transducer method andpressure membrane technique for suction measurement were merged in themodified triaxial testing apparatus enabling to acquire both elastic wave andmatric suction on cyclindrical specimen, was employed. A pair of disk transducer,
one in top cap and the other in pedestal, was encapsulated in the triaxial apparatus.

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Micro-porous membrane (made of polyether sulfone, thickness: 140 µm, air entry
value: 250 kPa) was utilized as a pressure membrane (Nishimura, 2010).

Figure2 Schematic plot of experimental set up
3. SPECIMEN PREPARATION AND TESTING PROCEDURE
3.1 Specimen preparation
This study had two motives; first, to study of the relevant deformation
characteristics of sand containing fines due to first infiltration as well as
successive infiltration within few hours. Second is to perform the test acquiring
elastic wave velocities and matric suction on fine sandy soil. Former case wasdealt with preparing the specimen having dimension 75 mm diameter by150 mm
height. The total soil was divided in 15 parts and each part is compacted within 10mm. Similarly, the specimen of 75 mm diameter and 75 mm height was preparedby tamping method for later case. The total soil was divided in 8 parts and eachpart is compacted within 10 mm. The specimen of 80 mm height was trimmed at
the top by 5mm that generated a 75 mm heighted specimen on the pedestal.
3.2 Testing procedure
The tested materials were tamped at atmospheric pressure and around 25 kPa
isotropic stresses (suction through top-cap and pedestal) were applied before
removing the mold. With setting cell cover, the cell pressure was gradually
increased up to 25 kPa with releasing suction at same rate. These all reflected thatthe specimen was prepared at isotropic stress state of 25 kPa. Then the stress level
was raised to 50 kPa. Two test procedures were employed to achieve thetestswave
for elastic
wave measurement
withmatricassociatedmatric suction on
Triaxial testsTriaxial
for elastic
measurementwith associatedsuctionunsaturated
fine
content
sandy
soil
on unsaturated fine content sandy soil693

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamaforementioned two goals. As schematically shown in Figure 3(a), the specimen
was subjected in creep condition controlling constant stress state for sufficient
time (nearly 12 – 18hrs). This creep stage is maintained for a long period to allow
measuring the consolidation deformation precisely and to distinguish thedeformation due to stress including creep with water induced collapse. A smallstrain cyclic loading and elastic wave measurement by disk transducer were
employed before starting wetting. The wetting of specimen was done bysupplying water from upper tank. The water was fed through pedestal and drainedout through top cap. To simulate the repeated infiltration condition in laboratory
specimen, the input water was stopped after initiating to outflow of water andthen allowed to deplete the water from the specimen through pedestal. For asufficient time, the specimen was kept in depleting condition and again fed thewater from bottom of the specimen. The strain and other parameters are measured
during the whole processes.
The next proceduce was shown in Figure 3 (b). In this process, the specimen was
subjected to constant stress state for sufficient time to maintain the stabilized
matric suction.The specimen was subjected in the several water content condition
by adding little amount of water and waited for stabilized matric suction. Withgetting the stabilized matric suction, elastic wave measurement was carried out.

a. Water induced deformation measurement

b. Matric suction and associated parameters measurement

Figure 3 Test procedure
4. TEST RESULT AND DISCUSSION
The list of the tests with the general information; size of specimens, initial
density, initial void ratio and initial water content are given in the Table 1. The

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first series of tests were carried out on higher specimens (h= 150 mm) and second
series were performed on shorter specimens (h = 75 mm).
Table 1: List of experiments on Edosaki sandInitial
Initial
InitialExperiment Speicmen
Relative
dry unit
void
water
RemarksNo.
dimension
densityweightratio
content3
mm x mm gm/cm %e%149.95 x
Edosaki-1
1.336
69.6
1.025
9.9
Isotropic
Ф74.97150.65 x
Edosaki-2
1.399
87.3
0.934
1.8
Isotropic
Ф74.92149.9 x Ф
Edosaki-3
1.304
60
1.074
2
Isotropic
74.64
150.85 x
Edosaki-4
1.34
70.8
1.019
1.9
Isotropic
Ф 74.75
150.45 x
Edosaki-5
1.386
83.8
0.952
4.5
Isotropic
Ф 74.55
151.25 x
Edosaki-6
1.371
79.6
0.973
1.8
Anisotropic
Ф 74.89
149.45 x
Edosaki-7
1.308
61.2
1.068
6.4
Isotropic
Ф 74.274.85 x Ф
Edosaki-8*
1.65
144.4
0.639
7.5
Isotropic
75.9
Edosaki76.25 x Ф
1.435
96.7
0.885
4
Isotropic
9**
72.53
76.55 x Ф
Edosaki-10
1.307
60.9
1.07
9.4
Isotropic
74.5
76.05 x Ф
1.366
78.2
0.98
6.5
Isotropic
Edosaki-11
74.81
76.85 x
Edosaki-12
1.42
92.8
0.905
7.9
Isotropic
Ф75.07
Note: *: densely compacted and **: reused specimen of Edosaki- 7
4.1 Water induced collapse (deformation)
The water infiltration process including repeated wetting was simulated in thelaboratory allowing water to be stopped and supplied as shown in the testing
sequence. The typical strain variations (axial, radial and volumetric) achieved on
the test, Edosaki-1 was shown in Figure 4. In this figure, the elapse time ofexperiment is plotted in X-axis in hours (Hrs.) and strain variations are plotted in
Y-axis in percentage (%). The axial, radial and volumetric strain increments areplotted in black, red and blue lines respectively. As shown in the figure, the strain
increments are always found to be contractive and significant changes can bebroadly separated into two parts. The initial variation was observed during stressspiking from 25 kPa e to 50 kPa. Behavior on creep was confirmed subjecting thetestswave
for elastic
wave measurement
withmatricassociatedmatric suction on
Triaxial testsTriaxial
for elastic
measurementwith associatedsuctionunsaturated
fine
content
sandy
soil
on unsaturated fine content sandy soil695

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnam

specimen into the creep condition for approximately 12 -18 Hrs. During creep
condition, slight changes in strains were observed.
The pre-eminent strain increments (both axial and radial direction) were observed
while the water was passed inside the specimen. This is generally termed as thecollapse during wetting. The water was stopped at time when just started to

Figure 4 Typical strain variations obtained in time domain series
outflow through top of specimen. Then water was then allowed to be depleted
from bottom of the specimen. After depletion, the specimen was again subjected
into wetting process by supplying water as previous. The experiments wereaccomplished performing wetting and drying processes as prior described. The
strain variations during all processes are monitored well in each case. It is noticed
that the strain increments in first wetting process was paramount. The volumetricstrain increments, calculated by axial and radial strains were plotted against theinitial density in Figure 5. The water induced volumetric strain was confirmed tobe nearly 7% at the loose state (ρ =1.3gm/cm3 and ρmax = 1.78gm/cm3 by standard
proctor test).
4.2 Matric suction and elastic wave velocity
The experiment was conducted in many steps by injecting a little water. Nearly 10– 20 ml of water was poured into the specimen and waited in creep condition
which tended to stabilize matric suction. The water was gradually added step bystep and elastic waves were measured in each step. Degree of saturation andmatric suction, for instance, as shown in Figure 6 were achieved. The apparent
drop down of the matric suction was noticed at tiny water adding. It indicates thatthe matric suction is highly sensible to water content. However, the possibility ofover-estimation was suspicious because the water content is locally increased inbottom. Erroneous in experiment was tried to reduced measuring the values on the
shorter specimen (h = 75 mm). The results obtained on Edosaki sand are plotted in

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Figure 7. The average trend line (red line in Figure 7), following to Fredlund andXing, 1994, was drawn. This figure shows the variation trend of the matric suctionof Edosaki sand and it possesses low range ofl matric suction (less than 100 kPa).

Figure 5 Volumetric strain increments obtained on Edosaki sandFigure 6 Degree of saturation and matric suction in time series

testswave
for elastic
wave measurement
withmatricassociatedmatric suction on
Triaxial testsTriaxial
for elastic
measurementwith associatedsuctionunsaturated
fine
content
sandy
soil
on unsaturated fine content sandy soil

697

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure7 Matric suction obtained on Edosaki sandThis study mainly focused on the unsaturated soil and its behavior. So, elastic
waves, both P and S waves, were propagated each step. P and S waveforms
achieved on the test: Edosaki – 8 at several moisture content conditions are traced
on Figure 8 [right: P waveforms and left:S waveforms]. The input signals areshown in lowest row in volt and the outputs in increasing order of degree ofsaturation. The output signals are plotted in millivolt unit. The estimated points ofarrival of received signal are pointed in the figure and it is seen that, withincreasing degree of saturation, the travel time is getting longer. As compared to
P wave, S waves are more sensitive to the moisture content. The travel time isnoticed to be significantly changed with degree of saturation. Same trends wereobserved in all tests. Observing the waveforms obtained on the Edosaki sand, theamplitude of the received signals are found to be very small. However, the signals
are enough to detect the arrival of the real signal. This is good evidence thatshows the well performance of the disk transducer method in unsaturated as wellas fine content sand.

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Figure8 P and S waveforms obtained on Edosaki sand specimen
The purpose of the performing test on the shorter specimen was to obtain thehigher reliable data to interpret the relations among the matric suction, elastic
wave velocities and water content or degree of saturation. The normalized P wave
velocities obtained on four tests (Edosaki -8 to Edosaki 12) are plotted against thedegree of saturation are given in Figure 9. Similarly S wave velocities obtainedon those tests are drawn with respect to the degree of saturation in Figure 10. The
normalized velocities; both P and S wave velocities, have found to not be
concisely normalized. P wave velocity have shown two trend lines, one resulted
by tests; Edosaki- 8 and Edosaki-12, another is resulted by tests; Edosaki – 10 and
Edosaki-11. Normalized shear wave velocities are also found to be scattering insome extent.

Triaxial testsTriaxial
for elastic
measurementwith associatedsuctiontestswave
for elastic
wave measurement
withmatricassociatedmatric suction on
on unsaturated
fine content
soilsandy soil
unsaturated
finesandy
content699

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 9 P wave velocity obtained on Edosaki sandFigure 10 S wave velocity obtained on Edosaki sand
4. CONCLUSIONS
Edoasaki sand, fine content sand collected from the Ibaraki prefecture of Japan
was tested to investigate the collapse behavior and mechanical properties. The
findings on the experiments are summarized as;
The strain variations due to water infiltration in edosaki sand reconstituted in
the laboratory were measured by means of LDT and clip gauges on triaxial
specimens. The collapse potential (volumetric strain) was observed to be varies

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in the ranges of 5 % - 7 %. These values are achieved on medium dense toloose specimens.
The first wetting induced volumetric strain increment are confirmed to be themost significant and following repeated wetting and drying cycles are notmuch worthy.
The matric suction activated in soil specimens of the Edosaki sand were
evaluated on triaxial specimen. It is confirmed that Edosaki sand possesses alittle matric suction (less than 100 kPa).
Elastic wave measurement on the Edosaki sand specimens were performed inpartially saturated conditions and its varying patterns were studies. The
received waveforms at varying degree of saturation were shown. The changes
in the elastic wave velocities were investigated.
Elastic wave measurement technique by disk transducer showed its
competency on unsaturated soil.

REFERENCES
Fredlund, D. G. and Xing, A., 1994. Equations for the soil-water characteristic
curve, Canadian Geotechnical Journal, Vol. 31, pp.: 521 – 532
Fredlund, D.G., and Morgenstern, N. R. 1977. Stress state variables forunsaturated soils, Journal of Geotechnical Engineering, ASCE, 103(5):447-466
Goto, S., Tatsuoka, F., Shibuya, S., Kim Y-S.and Sato, T. 1991. A simple Guage
for Local small strain Measurements in Laboratory. Soil and Foundations,31(1):169-180
Nishimura, T., Koseki, J., Fredlund, D. G., and Rahardjo, H. 2010. Microporous
Membrane Technology for Measurement of Soil-Water Characteristic Curve,
Geotechnical Testing Journal, 35 (1): 1-8

testswave
for elastic
wave measurement
withmatricassociatedmatric suction on
Triaxial testsTriaxial
for elastic
measurementwith associatedsuctionunsaturated
fine
content
sandy
soil
on unsaturated fine content sandy soil

701

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New Technologies for Urban Safety of Mega Cities in Asia

Effect of permeability of dam bodyand foundation on free surface
Thi Dieu Chinh LUU
Lecturer, Water resources and Hydropower engineering Department,
National University of Civil Engineering, Vietnam
luuthidieuchinh@nuce.edu.vn
ABSTRACTIn the stability analysis of slopes, particularly those related to earth dams, it isnecessary to estimate the location of the free surface or the phreatic surface. In
this paper, the finite element method is used to investigate the effect of thepermeability coefficients of the dam body and foundation on the free surface
location. Then these results are used to analyze the stability of Buon Kuop
embankment dam.
Keywords: permeability, embankment, free surface, dam, stability
1. INTRODUCTION
Seepage problem is one of the most important issues in design and construction ofdams and hydraulic structures. Seepage problems can be categorized into confinedand unconfined problems. First one refers to problems with known boundaries andthe second one refers to problems with unknown boundaries. Seepage flow
through the earth dams and groundwater seepage in unconfined aquifer are
samples of unconfined seepage problems. In unconfined seepage problems
determination the location of the free surface is the most important step in thesolution. Free surface is the boundary of the saturated and unsaturated zones in the
problem domain. (Ouria and Toufigh, 2009).
The slope stability and safety operation of earth dams are influenced greatly fromseepage problem which is characterized by the location of the free surface (Huang,1983). However the position of the free surface in earth dams cannot be
determined easily. Thus, free surface detection has been studied by many
researchers as a significant issue. (Mishra and Singh, 2005).
There are some methods to determine the free surface such as graphical flow net,
application of the Dupuit theory (Cedergren, 1977; Harr, 1962). However, thesemethods only apply for the cases with simple boundary conditions; the real works
often have the complicated boundary conditions which can be solved by using
many numerical methods such as the routine finite difference method, the finitevolume method, the boundary-fitted coordinate transformation method, the finite
element method, the numerical manifold method, the meshless method etc. (Bathe703

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamand Khoshgoftaar, 1979; Darbandi et al., 2007; Desai 1976; JIANG et al., 2010;
Jie et al., 2004; Lam & Fredlund, 1984; Li, Ge & Jie, 2003; Zheng et al., 2005).
Normally, the permeability coefficient of dam body will be determined exactly bysampling the compacted soil of dam body and testing in laboratory (Nguyễn et al.,1978), therefore its reliability is high. Meanwhile the geology in the dam
foundation is often very complicated including geology in the river-bed and two
abutments in which the number of the geological survey bores are often limited,
so it is difficult to determine the exact permeability coefficient of dam foundation.
In this paper, the Finite Element Method (FEM) is used to model a series of casesof earth dam with toe filter in which permeability coefficients of dam body (Kd)and foundation (Kf) are ranged within: Kf/Kd = 1÷50 times and Kd/Kf = 1÷50
times in order to survey the effect of permeability coefficients of dam body andfoundation on free surface location.
2. PERMEABILITY ANALYSIS
2.1 Two-dimensional flow, stream function
Physically, all flow systems extend in three dimensions. However, in many
problems the features of the groundwater motion are essentially planar, with the
motion being substantially the same in parallel planes. For these problems weneed concern ourselves with two-dimensional flow only, and thereby we are able
to reduce considerably the work necessary to effect a solution. Fortunately, incivil engineering the vast majority of problems fall into this category.
Assuming the y axis as vertical (positive up) and the x axis as horizontal, velocity
potential (x,y) will satisfy the Laplace’s equation (1) and equation of continuity(2) as follows: 2  2   2  2 0
x
y

(1)

u v

0
x y

(2)

2

where u, v are the components of the seepage velocity in x axis and y axis
respectively.
The stream function (x,y) also satisfies the equation of continuity and the
Cauchy-Riemann equations and hence the equation of Laplace, (Harr, 1962).
 2 

704

 2  20x 2 y 2(3)

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The free surface is the upper streamline in the flow domain. It separates thesaturated region of flow from the part of the soil body through which no flow
occurs. The determination of its locus is one of the major objectives ofgroundwater investigations.
2.2 Increasing permeability coefficient of foundation, Kf/Kd = 1÷50
A series of calculations in case of earth dam with toe filter and Kf ≥ Kd are
conducted and the changes in free surface are shown in Figure 1.
Ear t h dam wit h t oe f il t er
Kd=Kf
5Kd=KfCoefficient of permeability of foundation is increased
K f K d= 1.e-006 (m/s)

Kf  Kd= 1 to 50

K = 1.e-001 (m/s)

15Kd=Kf
100
90
80

Y (m)

70

TF

50Kd=Kf
Upstream level

30Kd=Kf

60
50

Downstream level

40
30
20
10
0

5 15 25 35 45 55 65 75 85 95 105 115 125 135 145 155 165 175 185 195 205 215 225 235 245 255 265 275 285 295 305 315 325 335 345 355 365 375

X (m)Figure 1: The free surface in case of earth dam with toe filter and Kf ≥ Kd
The results show that when increasing the proportion of Kf/Kd = 1÷50, the freesurface goes down according to the increase of permeability coefficient of Kf or
the more permeability coefficient of Kf increases, the more free surface goesdown.
2.3 Increasing permeability coefficient of dam body, Kd/Kf = 1÷50
A series of calculations in case of earth dam with toe filter and Kd ≥ Kf are
conducted and the changes in free surface are shown in Figure 2.

Effect of permeability of dam body andfoundation
on free of
surface
Effectof permeability
dam body and foundation on free surface705

October
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Vietnam

EARTH DAM WITH t oe FILTER
Permeability coefficient of dam body is increased
Kd=50Kf
Kd=10Kf
Kd=Kf

Kd Kf = 1.e-006 (m/s)
K = 1.e-001 (m/s)
TF

Kd / K f = 1 to 50

100
90
80

Y (m)

70

Kd=5Kf
Upstream Level

60
50

Downstream Level

40
30
20
10
0

5 15 25 35 45 55 65 75 85 95 105 115 125 135 145 155 165 175 185 195 205 215 225 235 245 255 265 275 285 295 305 315 325 335 345 355 365 375

X (m)Figure 2: The free surface in case of earth dam with toe filter and Kd ≥ Kf
The results show that when increasing the proportion of Kd/Kf = 1÷50, the freesurface rises according to the increase of permeability coefficient of Kd or the
more permeability coefficient of Kd increases, the more free surface rises.
3. Case study of Buon Koup earth dam
Earth dam seepage problem in the initial working time of the dam is the mostimportant factor to consider. According to Vietnamese regulations, all the earthrock dam of grade I to V must install the permeability monitoring equipment. It isnecessary to analysis these data to evaluate the stability of dam.
Buon Kuop hydropower project which is the second largest in the Central
Highland of Vietnam has an installed capacity of 280 (MW) and its electricity
output is 1458.6 million kWh per year. Buon Kuop dam foundation is basalt rock,
especially it has the porous basalt layers mixed with foam, and therefore thepermeability of this layer is very complex. The installation of the monitoring
equipment aimed to control the work of Buon Kuop dam.
It is considered the typical cross section 9-9 of the dam which includes theseepage observation holes: QTT9-1 (at crest dam of 415.5 (m)), QTT9-2 (atdownstream slope elevation of 407.5 (m)) and QTT9-3 (at downstream slope
elevation of 402.5 (m)). In the cross section 9-9, it is started to monitor the
seepage holes from 25th February 2009 (at downstream water level of 397 (m)).
The seepage monitoring data of the cross section 9-9 in dam-body showed that the
seepage water level are pulled down much lower than the downstream water level(from 25-27 (m)), and the difference among the observation holes is not highwhich indicates that the earth-fill is consolidated and the observed free surface issuitable.

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In this study the seepage of the Buon Kuop embankment dam body is numericallymodel by FEM. This analysis is numerically modeled by observational headpiezometric data and it is compared between the predicted free surface and theobserved free surface. As a result, it is showed that the observed free surface ismuch lower than the predicted free surface. The reason for this result is that Buon
Koup dam foundation is porous basalt layers mixed with foam of whichpermeability coefficient is much larger than the permeability coefficient taken in
the design stage. The free surface is dropped significantly and it is comply withpermeability analysis in Figure 1. Then the comparison is shown in the Figure 3.
Cross Section 9-9
QTT 9_1
QTT 9_2

Normal water level = 412.0

QTT 9_3

Predicted free surface
Observed free surface
X

X

X
X

X

X

X

X

X

X

XX

X

X

XX

Figure 3: The predicted free surface and the observed free surface
In next step, the stability of dam in the cross section 9-9 is analyzed according to
the locations of the predicted free surface and the observed free surface
respectively.

Figure 4: The stability analysis result of Cross section 9-9 according to thelocation of the predicted free surface; stability coefficient K = 1.65

Effect of permeability of dam body andfoundation
on free of
surface
Effectof permeability
dam body and foundation on free surface707

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 5: The stability analysis result of Cross section 9-9 according to thelocation of the observed free surface, stability coefficient K = 1.85
The stability analysis results as shown in Figure 4 and Figure 5 clearly illustratethat when the free surface goes down, the stability coefficient of dam increases.
On the other hand, it is obvious that when the permeability coefficient of dam
foundation is too high such as the foundation of gravel, pebble, it is not necessary
to layout the toe filters in dam body because the coefficient of permeability offoundation is nearly equivalent to the permeability coefficient of toe filters indesign.
4. CONCLUSIONS AND RECOMMENDATIONSIn this study, FEM is used to analyze the case of earth dam with toe filter of whichpermeability coefficients of dam body (Kd) and foundation (Kf) are ranged within:
Kf/Kd = 1÷50 times and Kd/Kf = 1÷50 times. The results show that due to thecoupling effect of permeability coefficient of dam body and foundation, thelocation of free surface depends on the proportion of Kd/Kf. In addition, the more
permeability coefficient of Kf increases, the more free surface goes down; and themore permeability coefficient of Kd increases, the more free surface rises.
Based on the analysis results of seepage observation data of Buon Kuop dam, it isrecommended that in case of limitation of the geological survey in the river-bed
and two abutments of dam foundation, the permeability coefficient of foundationin design calculation should have a smaller value bias in order to ensure safe
operation of the dam.

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REFERENCES
Bathe, K. J. and Khoshgoftaar, M. R., 1979. Finite element free surface seepage
analysis without mesh iteration. International Journal for Numerical andAnalytical Methods in Geomechanics 3, 13–22.
Cedergren, H. R., 1977. Seepage Drainage and Flow Nets. John Wiley, NewYork.
Darbandi, M., Torabi, S. O., Saadat, M., Daghighi, Y., and Jarrahbashi, D., 2007.
A moving-mesh finite-volume method to solve free-surface seepage problem inarbitrary geometries. International Journal for Numerical and Analytical Methods
in Geomechanics 31, 1609–1629.
Desai, C. S., 1976. Finite element residual schemes for unconfined flow.
International Journal for Numerical Methods in Engineering 10, 1415–1418.
Harr, M. E., 1962. Groundwater and Seepage. Dover Civil and MechanicalEngineering Series, Dover.
Huang, Y., 1983. Phreatic Surfaces. Stability Analysis of Earth Slopes, Springer
US, 40–51.
Jiang, Q., Deng, S., Zhou, C., and Lu, W., 2010. Modeling Unconfined Seepage
Flow Using Three-Dimensional Numerical Manifold Method. Journal of
Hydrodynamics, Ser. B 22, 554–561.
Jie, Y., Jie, G., Mao, Z., and Li, G., 2004. Seepage analysis based on boundaryfitted coordinate transformation method. Computers and Geotechnics 31, 279–283.
Lam, L., and Fredlund, D. G., 1984. Saturated-Unsaturated Transient Finite
Element Seepage Model for Geotechnical Engineering. In Laible, J. P., Brebbia, C.
A., Gray, W., and Pinder, G. (editors), Finite Elements in Water Resources,
Springer Berlin Heidelberg, 113–122.
Li, G., Ge, J., and Jie, Y., 2003. Free surface seepage analysis based on theelement-free method. Mechanics Research Communications, vol. 30, 9–19.
Mishra, G., and Singh, A., 2005. Seepage through a Levee. International Journalof Geomechanics, vol. 5, 74–79.
Nguyễn, C. C., Nguyễn, V. C., Lưu, C. Đ., and Hoàng, V. Q., 1978. Thủy lực, vol.
2, Đại học và Trung học chuyên nghiệp, Hà Nội.
Ouria, A., and Toufigh, M. M., 2009. Application of Nelder-Mead simplex
method for unconfined seepage problems. Applied Mathematical Modeling 33,
3589–3598.
Zheng, H., Liu, D. F., Lee, C. F., and Tham, L. G., 2005. A new formulation of
Signorini’s type for seepage problems with free surfaces. International Journal
for Numerical Methods in Engineering, vol. 64, 1–16.

Effect of permeability of dam body andfoundation
on free of
surface
Effectof permeability
dam body and foundation on free surface709

October 2013, Hanoi, Vietnam

710

New Technologies for Urban Safety of Mega Cities in Asia

Experimental application of biogrout
to sand with fines
1

Tsubasa Sasaki1 and Reiko Kuwano2
Graduate student, Dept. of Civil Engineering, The University of Tokyo, Japantsubasas@iis.u-tokyo.ac.jp
2
Professor, IIS, The University of Tokyo, Japan

ABSTRACT
Soil improvements with biogrout have the potential to mitigate geodisasters withminimal adverse consequences on the environment. However, applicability of thistechnique remains unaddressed for sand which contains fines. In this research,small specimens were prepared using two different sorts of sand, namely Toyoura
sand and Edosaki sand, with only the latter containing fines, for the effect of the
improvement on the sand with fines can be compared with that on the normal
sand which has already proven to be suitable for biogrout. The specimen was
injected with Biogrout containing Sporosarcina pasteurii (ATCC 11859), an
ubiquitous microbial strain capable of mediating calcium carbonate precipitation,and urea-calcium ion medium, in order to induce calcium carbonate among thespecimen, which binds soil particles together and increases the strength. The
result showed that while the efficiency of calcium carbonate precipitation wasalmost 100 % for Toyoura sand and its strength doubled, that for Edosaki sandwas merely about 40 % and there was not a distinct increase in its strength. Thesefindings might indicate that the effectiveness of biogrout could be hindered forsand with certain levels of fines content.
Keywords: soil improvement, biogrout, microbe, sand with fines, calcium
carbonate precipitation
1. INTRODUCTION
Biogrout has a great prospect of mitigating soil-related disasters such asliquefaction and landslides while presenting the minimal level of harsh effects on
the environment. Biogrout normally means a solution containing specificmicrobes, urea and calcium sources; they work to solidify soil as follows. Firstly,
the specific microbes produce urease enzymes, which decompose urea into
ammonia and carbon dioxide. Then, the ammonia raises pH in the surrounding
environment, helping the carbon dioxide to become carbonate ion. With thepresence of ample calcium ion in addition to the carbonate ion, calcium carbonate
precipitation happens near particle-particle contacts among soil, eventually
reinforcing soil structures and increasing its strength.
Many pieces of existing research has already suggested that biogrout can beeffective in improving the soil in terms of its undrained behaviors (DeJong et al.
2006), unconfined compressive strength (van Paassen et al., 2009) and confined711

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamcompressive strength (Whiffin et al., 2007). However, all of these studies
employed soils which contain no or marginal amount of fines (i.e. soil particles
smaller than 75 �m in diameter), partly owning to the convenience provided byhigh permeability of these soils, with which biogrout can readily infiltrate andinduce calcium carbonate precipitation.
Several studies have been carried out in an attempt to cement clay or sandwith high levels of fines content using biogrout, and difficulties were experienced
in most cases. Rebata-Landa (2007) applied biogrout to kaolinite clay, which
resulted in no precipitation of calcium carbonate. In the same study, survivabilityof microbes was examined by putting them in soils with various grain sizes undera wide range of overburden stress, and it was found that in the soils whose d10 (i.e.
10 % of the soil particles by weight is smaller than this value in diameter) is lessthan 1 �m, microbes are not likely to survive for longer than 72 hours under the
overburden stress levels equivalent to a depth of 1 m or deeper from the groundsurface. Mortensen et al. (2011) employed a fine soil whose d10 was 2 �m andcame up with a similar result, showing delayed and reduced precipitation of
calcium carbonate.
Among the possible contributing factors to the reduced calcium carbonate
precipitation in sand with fines are mechanical constraints which prevent asmooth transfer of microbes to the soil, giving rise to their entrapment, and low
permeability which often causes delayed delivery of biogrout, leading to theprecipitation before biogrout is disseminated throughout the target soil. Hence, inthis study an experiment was carried out, where biogrout was infiltrated at anincreased flow rate into the specimen comprising sand with or without fines, in an
attempt to make calcium carbonate precipitation occur in a better way in terms of
its efficiency and distribution.
2. MATERIALS AND METHODS
2.1 Biogrout Preparation
As was already mentioned, biogrout is often recognized as urea-calcium ion
medium containing microbes capable of producing urease enzyme. However, it
was anticipated that it would take long duration to infiltrate biogrout into thespecimen of Edosaki sand, meaning calcium carbonate precipitation could occur
before the specimen is saturated with biogrout. Hence, biogrout was separated
into microbial solution and cementation solution; the former contained themicrobes and the latter was constituted of urea-calcium ion medium.
2.1.1 Microbial Solution
Microbial solution was prepared by inoculating an arbitrary amount of
Sporosarcina pasteurii (ATCC 11859), which had been cultivated on culture
plates, into 0.13M Tris buffer at around pH 9.0 that also contained 20 g of yeast
extract and 10 g of ammonium sulfate per 1 liter. Yeast extract and ammonium
sulfate were put into separate flasks containing Tris buffer, and they weresterilized at 121 oC for 20min before mixing. The recipe for the culture plate is
identical to that for microbial solution except 20 g of agar per liter being added to712

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make it gelled. After the inoculation, the solution was incubated for 24 to 26 hours
at 30 oC in order to let the microbes to augment up to a stationary phase.
2.1.2 Cementation Solution
Cementation solution mainly comprised urea and a calcium source; the former
provides energy for the microbes and the latter is essential to induce calcium
carbonate precipitation. Specifically, cementation solution employed in theexperiment contained 30.03 g of urea, 73.507 g of calcium chloride bihydrate, 3 gof nutrient broth, 10 g of ammonium chloride and 2.12 g of sodium bicarbonate
per liter of distilled water. Nutrient broth provides necessary nutrition for the
microbes to augment, and ammonium chloride and sodium bicarbonate stabilize
pH levels of the solution. Cementation solution was not sterilized prior to theinjection to the specimen. All the chemicals used to prepare microbial andcementation solution were obtained from Wako Pure Chemical Industries, Ltd.,
Japan.
2.2 Specimen Preparation
The specimen of Toyoura sand (Gs = 2.656, emax = 0.992, emin = 0.632, d50 = 180
�m, Fc = 0 %) was prepared by water-pluviating the sand into a cylindrical plastic
mold (�50 mm×100 mm), aiming at a relative density of 90%. A filter paper wasplaced at the top and bottom of the sand column to prevent a loss of sand particles.
As for the specimen of Edosaki sand (d50 = 156 �m, Fc = 17.5 %), the waterpluviation method was not applicable since Edosaki sand has high fines content
and those fine particles were expected to be suspended in the water instead ofbeing deposited with the larger particles, making it difficult to prepare a specimen
with uniform grain size distribution. Hence, Edosaki sand had been compacted
into the mold using a brass rod until its dry density was stabilized at 1.55 g/cm3,and then a filter paper were put at the top and bottom of the column. Figure 1
shows the grain size distribution of Toyoura sand and Edosaki sand.
Percentage finer by weight (%)

100
90
80
70
60
50
40

Toyoura sand
Edosaki sand

30
20
10
0

0.1

Grain size (mm)1Figure 1: Grain size distribution of Toyoura sand and Edosaki sand
2.3 Test Procedures
2.3.1 Specimen Solidification with Biogrout
The specimen was fitted with an acrylic hollow cylinder at the top of the mold anda plastic tube at the bottom so that the infiltration of biogrout (i.e. microbial
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The tube was connected to a small tank where negative pressure was applied tocontrol the flow rate of biogrout (Figure 2), and microbial solution was transferredfirstly to the specimen followed by cementation solution. Various levels ofnegative pressure were used, ranging from 0 kPa to -40 kPa, and the pressure wasadjusted manually so that hydraulic gradient could be maintained when the waterlevel declined as the infiltration proceeded. 90 ml of microbial solution andcementation solution were used for the solidification of a single specimen. Further
details about test conditions for each specimen are summarized in Table 1. The
infiltration was stopped while the top surface of the column was still slightly
covered by the solution. The specimen was detached from the tank after the
infiltration, and its top and bottom end were sealed properly in order to prevent
drying of the sand. The specimen was retained for 20 hours after the infiltration of
cementation solution had started, in order to let calcium carbonate precipitation
develop. Then, distilled water was added from the top to cease the precipitation
process and to wash out all the remaining chemical substances in the specimen.
biogrout

Pressure tank (negative
pressure applied inside)

Effluent

A plastic moldpacked with sandFigure 2: Infiltration of biogrout to the specimen
2.3.2 Measurement Procedures
The degree of cementation and its distribution were evaluated by needle
penetration tests, in which the cemented sand column was pierced for a designateddepth (e.g. 20 mm for Toyoura sand and 30 mm for Edosaki sand) from the top
surface with a needle whose diameter was 3 mm. The resistance on the needle wasrecorded as it descended in the specimen at a speed of about 30 mm/min. After the
first layer was done, it was excavated from the mold, and the next layer underwent
the test. This had been repeated until the entire column was finished with thepenetration test. In addition, the amount of precipitated calcium carbonate wasestimated in two different ways; one was based on the concentration of calcium
ion in the effluent of cementation solution ejected from the specimen (i.e.
chemical efficiency), and the other is derived by comparing the weight differenceof the specimen before and after the treatment (i.e. precipitation efficiency). The
effluent was also examined to assess its pH level.

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3. RESULTS AND DISCUSSION
The results of penetration tests are shown in Figure 3 and 4. Specifically, theresults with the specimen of Toyoura sand are shown in Figure 3, and Figure 4
reveals those of Edosaki sand. Each symbol shown in the graphs (e.g. 1-a)corresponds to a combination of Test number and Column in Table 1.
Test number

Table 1 : Test conditions and results for each specimen
12

ColumnMaterial
Relative density (%)
Dry density (g/cm3)

a

b

c

d

89.
3
1.5
9

Toyoura sand91. 96. 91.
1
95
1.6 1.6 1.6
0
2
0

BM
102.
5
1.64

a

b

c

d

Edosaki sand

B
M

-

-

-

-

-

1.5
5

1.5
5

1.5
5

1.5
5

1.5
5

Hydraulic gradient for
30 40 10
1
5
30
5
1
MS
Duration of MS
0.4 0.7
1.2 3.2
68 34 80 380
infiltration (min)6
8
Hydraulic gradient for
1
1
1
1
5
5
5
1
CS
Duration of CS
5.8 6.8 7.0 4.6
93 112 95
infiltration (min)Chemical efficiency
96. 97. 98. 97.
12. 27.
38.
0
(%)
5
3
1
0
7
6
6
Effluent pH
7.5 7.3 7.5 7.3
7.1 7.0 6.8 6.8
Note: MS = microbial solution; CS = cementation solution; BM = benchmark-

In the case of the specimen of Toyoura sand, calcium carbonate precipitation
successfully took place with high degrees of chemical efficiency; it was almost
100 % for all the treated specimens. The strength of the sand represented bypenetration resistance is about twice as high as that of the benchmark result (i.e.
no treatment with biogrout) at the end of each layer: as high as 40 N for theuntreated benchmark specimen compared to up to 200 N for the solidified
specimen with biogrout. In addition, it can be inferred that the quicker the
infiltration of microbial solution was, the more uniform precipitation happened,since the relationships between penetration depth and resistance for different
layers were more similar to each other as the duration of the infiltration was
shortened. Note that the drop in penetration resistance near the end of the fifthlayer is because of the outlet hole drilled at the bottom of the mold, which
provided much less penetration resistance to the needle compared to the upper
layers, so the decrease in the fifth layer can be ignored.

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Penetration depth (mm)01-aChemical efficiency : 96.5%

5

1st layer
2nd layer
3rd layer
4th layer
5th layer

10

15

20
0

(b)
Penetration depth (mm)

0

50

100

Penetration resistance (N)

150

200

1-b
Chemical efficiency : 97.3%

5

1st layer
2nd layer
3rd layer
4th layer
5th layer

10

15

20
0

(c)
Penetration depth (mm)

0

50

100

150

Penetration resistance (N)

200

1-c
Chemical efficiency : 98.1%

5

1st layer
2nd layer
3rd layer
4th layer
5th layer

10

15

20
0

716

50

100

150

Penetration resistance (N)200

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Penetration depth (mm)01-dChemical efficiency : 97.0%

5

1st layer
2nd layer
3rd layer
4th layer
5th layer

10

15

20
0

(e)

50

100

150

Penetration resistance (N)200

Penetration depth (mm)

0

1-BM
5

(No treatment)

1st layer
2nd layer
3rd layer
4th layer
5th layer

10

15

20
0

50

100

150

Penetration resistance (N)200

Figure 3: Result of penetration tests for the specimen of Toyoura sand;(a) ~ (d) solidified specimens with biogrout; (e) untreated specimen(a)Penetration depth (mm)02-aChemical efficiency : 12.7%

5
10

1st layer
2nd layer
3rd layer

15
20
25
30

0

5
10
Penetration resistance (N)ExperimentalExperimental
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Penetration depth (mm)

0

10

20
25
0

Penetration depth (mm)

0

(d)

15

20

10

1st layer
2nd layer
3rd layer

15
20
25
0

0
Penetration depth (mm)510Penetration resistance (N)2-cChemical efficiency : 0%

5

30

5
10
Penetration resistance (N)

15

20

2-d
Chemical efficiency : 38.6%

5
10

1st layer
2nd layer
3rd layer

15
20
25
30

718

1st layer
2nd layer
3rd layer

15

30

(c)

2-b
Chemical efficiency : 27.6%

5

0

5
10
Penetration resistance (N)1520

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Penetration depth (mm)

0

2-BM

5

(No treatment)

10

1st layer
2nd layer
3rd layer

15
20
25
30

0

5
10
Penetration resistance (N)15

20

Figure 4: Result of penetration tests for the specimen of Edosaki sand;(a) ~ (d) solidified specimens with biogrout; (e) untreated specimen

Precipitation Efficiency (%)

100

Toyoura sand
Edosaki sand

80
60
40
20
0

-20

0

20

40

60

Chemical Efficiency (%)

80

100

Figure 5: Correlation between chemical and precipitation efficiency
On the other hand, biogrout seemed ineffective in solidifying the specimen of
Edosaki sand as the increase in penetration resistance was minimal compared tothe benchmark result. Moreover, chemical efficiency was merely as high as about
40 % and no precipitation occurred in one of the specimens treated with biogrout.
This tendency was further evidenced by the low pH levels in the effluent, which
imply that there was not as successful microbial decomposition of urea in Edosaki
sand as in Toyoura sand. Quicker transfer of biogrout by higher hydraulic gradientappeared meaningless in helping the distribution of the precipitation become more
uniform in Edosaki sand as opposed to the case of Toyoura sand; the bottom layer
saw the biggest increase in penetration resistance for most of the treatedspecimens regardless of test conditions, although usually precipitation of calcium
carbonate (i.e. increase in the strength) tends to concentrate near the inlet of thespecimen from which biogrout is infiltrated (Martinez et al. 2011, 2013,
Mortensen et al. 2011, Whiffin et al. 2007, van Paassen et al. 2009). These results
might suggest that microbes could not attach themselves on the surface of soil
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Vietnamparticles when microbial solution was infiltrated into the specimen and were
washed out during the subsequent infiltration of cementation solution, leaving theresidual microbes around the bottom of the specimen. Whether this was caused
due to the presence of fines or other factors including effects of minerals in
Edosaki sand needs to be investigated.
The correlation between precipitation efficiency and chemical efficiency isshown in Figure 5. It seems that the efficiency acquired by measuring theconcentration of residual calcium ion in the effluent (i.e. chemical efficiency)
yields similar values to the ones derived by comparing the weight difference ofthe specimen before and after the treatment (i.e. precipitation efficiency),
indicating that chemical efficiency can be used as an alternative to estimate theamount of precipitated calcium carbonate in the soil.
4. CONCLUSIONSIn this study, biogrout was used to solidify the specimen of Toyoura sand andEdosaki sand, with only the latter having fines content. Even though Toyoura sandwas readily cemented with calcium carbonate, with its strength almost doubled,
Edosaki sand was precipitated with merely 40 % maximum possible amount ofcalcium carbonate, resulting in no distinct increase in the strength. The pH levelsin the effluent also demonstrated this tendency; lower values were recorded for
Edosaki sand, indicating that the microbes were not active enough to decompose
all the urea molecules in biogrout. Potential causes for the reduced precipitation of
calcium carbonate in Edosaki sand need to be investigated, in order to find a way
to effectively solidify sand with fines using biogrout.
REFERENCES

Dejong, J.T., Fritzges, M.B. and Nüsslein, K. (2006):”Microbially induced
cementation to control sand response to undrained shear”, J. Geotech.
Geoenviron. Eng., 132, pp1381-1392
Martinez, B.C., DeJong, J.T., Ginn, T.R., Montoya, B.M., Barkouki, T.H., Hunt,C., Tanyu, B. and Major, D. (2013): “Experimental optimization of microbialinduced carbonate precipitation for soil improvement”, J. Geotech.
Geoenviron. Eng., 139, pp587-598
Martinez, B.C., Barkouki, T.H., DeJong, J.T. and Ginn, T.R. (2011); “Upscalingof microbial induced calcite precipitation in 0.5m columns: experimental andmodeling results”, Proc., ASCE Geo-Frontiers 2011 Conf., ASCE, Reston,
VA., pp4049-4059
Mortensen, B.M., Haber, M.J., DeJong, J.T., Caslake, L.F. and Nelson, D.C.
(2011): “Effects of environmental factors on microbial induced calcium
carbonate precipitation”, Journal of Applied Microbiology, 111, pp338-349
Rebata-Landa, V. (2007): Microbial activity in sediments: effects on soil behavior,
Doctoral Dissertation, Georgia Institute of Technology, Atlanta, GA, U.S.A.
van Paassen, L.A., Harkes, M.P., van Zwieten, G.A., van der Zon, W.H., van derStar, W.R.L. and van Loosdrecht, M.C.M. (2009): “Scale up of BioGrout: a

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biological ground reinforcement method”, Proc., the 17th International
Conference on Soil Mechanics and Geotechnical Engineering, pp2328-2333
Whiffin, V.S., van Paassen, L.A. and Harkes, P.M. (2007): “Microbial carbonate
precipitation as a soil improvement technique”, Geomicrobiology Journal, 24,
pp417-423

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The deformation of flexible pipe buried in soil
with different degree of compaction
1

Ngoc Duyen NGUYEN1 and Reiko KUWANO2
Master Student, ICUS, IIS, the University of Tokyo, Japanduyen@iis.u-tokyo.ac.jp
2
Professor, ICUS, IIS, The University of Tokyo, Japan

ABSTRACT
Flexible pipes have been utilized widespread in over the world for water, gas,
sewage pipelines and many other purposes, especially in megacities. The need forstudies on pipes becomes necessary for design and construction. One of importantfactors affecting its performance is the compaction of backfill around the pipe.
Moreover the pipe’s behavior under cyclic loading has not been fully investigated.
A series of model tests with different degree of compaction has been conductedusing the 32 sensor mounted pipe. It was found that with the better backfill
compaction the lesser deformation the pipe showed. The study also clarifies thechange in pipe deformation under the cyclic loading. The bending strain in thelooser backfill compaction at the last cyclic loading is largely higher than thedense case, which further proves the importance of compaction work in practice.
The performance of buried pipe when the backfill soil was improved only aroundthe pipe was also studied.
Keywords: flexible pipe, cyclic loading, deformation, density of backfill.

1. INTRODUCTION
The urbanization and expanding the big cities in all over the world are the reasonsfor the large application of pipes such as water supply, sewage and many otherpurposes. Therefore, research for the influential factors on their lifespan plays animportant role. Besides the subjective factors such as pipe stiffness (PS), site
conditions, etc., backfill compaction and loading modes also significantly impact
on pipe behavior. The role of compaction has been affirmed, however, theperformance under the cyclic loading which is another form of traffic loading has
not been fully investigated. A series of model tests with different degree ofcompaction under the cyclic loading has been conducted using the 32 sensor
mounted pipe.
This paper presents the results of this series of experiments, which again confirm
the critical effect of compaction to the buried pipe performance. Additionally, thebehavior of buried pipe when backfill soil was improved only around the pipe wasalso studied. Under the same cyclic loading mode, the extent of deformation
belongs to the pipe is clarified.

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2. METHODOLOGY
2.1 Material
The material using for experiments is silica sand, the artificial standard sand forlaboratory, which is fine-sized, uniformly graded sand. It is milky white in color
with mostly well-rounded particles. Manufactured by grinding the natural rocks
with specific strength, the silica sand has become a good substitute for the natural
sands.
In this research, silica sand No. 7 was used. Figure 1 exhibits the grain size
distribution curve.

Figure 1: Grain size distribution curve of silica sand No. 7
2.2 Apparatus
2.2.1 Soil chamber
The experiments were all conducted in a large soil chamber having a dimension of
98 cm long, 40 cm wide and 80 cm high. The chamber which is made oftransparent acrylic board is strong enough so that not to be deformed in theexperiments.
2.2.2 Automated stress-controlled loading system

Figure 2: Soil chamber and loading system

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The loading apparatus is automated stress-controlled loading system that consistsof a bellofram cylinder, a pressure tank, E/P transducer, regulators and boosters.
The air pressure is applied and amplified by control panel. Figure 2 shows the soilchamber and loading system.
2.2.3 Model Pipe
The model pipe is PVC pipe (VU125 – 140 mm diameter and 4.1 mm thick). In
order to fully study the pipe behavior, the normal stress, shear stress anddeformation of pipe were taken into account, which were derived from the sensors
evenly attached on the pipe at different location. The sensor quantity is as in Table
and theirs allocation is as Figure 3.
Table 1: The sensor quantity
Force
Normal stress
Shear stress
Inner strain
Outer strain
Vertical displacement transducer
Horizontal displacement transducer

Quantity
08
08
08
08
01
01

Figure 3: The sensor allocation
The two-way load cells have been utilized to measure the normal stress and shear
stress; the strain gauges that attached directly to the pipe are used to measure thestrain inner and outer of buried pipe. Figure 4 shows imagines of the two-way
load cell and strain gauge that were used in these experiments.

(a)(b)
Figure 4: Two-way load cell (a) and strain gauge (b)The deformation of flexible pipe buried in soil with different degree of compaction
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2.3 Testing procedure
The experiments were all conducted in the soil chamber. To completely describe
the interaction between backfill and pipe as well as the effect of different degreeof compaction under the cyclic loading, the subsequences of the tests were thesame except for the relative density of the initial backfill around the pipe: loose(Case 1), dense (Case 2) and improved backfill only around the pipe (Case 3). All
the model grounds were prepared by the air pluviation method. The relative
density for two states loose and dense is 33% and 89%, respectively. Figure 5
shows the experiment schematic of Case 1, Case 2 and Case 3.

Figure 5: Experiment schematic
The pipe was placed on the 20 cm thickness of dense sand as the base. Then, thebackfill of which relative density was controlled by the size of the hole in themetal plate was pouring into the soil chamber from the constant height. The
footing plate made of high stiffness duralumin was placed onto the surface.
Finally, the cyclic loading was applied.
Due to the high stiffness of soil chamber and footing plate, the model tests were
all considered to be one-dimensional compression. A vertical pressure of 10 kPa
was first applied, then a cyclic loading of 50 kPa following by 30 minutes creep.
Each loading stage including cyclic loading and creep repeated 3 times.
3. RESULTS
3.1 Footing settlement
Under the cyclic loading, the ground surface tends to settle down. Its magnitudedepends mainly on the compaction of backfill. Among three cases, Case 1 ispredicted to have the largest displacement, following by Case 3 and Case 2.
However, the disparity in magnitude of three cases needs clarifying.
The experiment results show the close coincidence with the expectation.
Undergoing 50 kPa cyclic loading, the settlement magnitude of Case 1 is as twice
as Case 2. However, Case 2 and Case 3 exhibit the similar movement. Figure 6
shows the relationship between displacement and vertical tress in three cases.

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Case 1 - Loose

Vertical stress (kPa)

60

50

40

30

20

10

0

0

5

15

Case 2 - Dense

60

Vertical stress (kPa)

10

Displacement (mm)

50

40

30

20

10

0

0

5

10

15

Displacement (mm)Vertical stress (kPa)

60

Case 3 - Improved around the pipe

50

40

30

20

10

0

0

5

10

Displacement (mm)15Figure 6: The relationship of vertical stress and displacement in three cases
In Case 3, there was no stable boundary between the dense and loose backfill
around the pipe, which means when the model pipe was subjected to the cyclicloading, there was a shift in these two zones. This shift became larger when thepipe experienced three-stage cyclic loading, which reasons for why even when thepipe was improved by denser backfill around, the displacement is the same with
Case 1.

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3.2 Pipe deformation
Three cases of experiment investigated the reaction of buried pipe when cyclicloading applied in three stages for 100 cycles. The stress acting on the pipe invertical and horizontal direction was plotted against the respective displacementof the pipe.
The Figure 7 shows the relationship in vertical displacement in dense and loose
case. The normal stress was derived by LC1 and LC5 against the pipe’s verticaldisplacement. It is clear that in Case 2 the displacement is critically smaller thanin Case 1 not only in the magnitude of displacement but the normal stress as well.
Moreover, the recorded data in LC1 and LC5 (approximately 150 kPa) exceeded
the loading applied (60 kPa) causes wondering. The reason for this phenomenon
can be explained by arching effects. Arching effect is stress redistribution bywhich stress is transferred a region of soil mass, which then subjected to lower
stress. In loose backfill, the sand around the pipe is stronger than the other areas.
That is the explanation when the model pipe undergoes the cyclic loading, thesearea support larger load than other zones.
Case 1 - Loose

LC5
LC1

Normal stress (kPa)

150

100

50

0

Case 2 - Dense
150

100

50

0

0.0

0.5

1.0

1.5

2.0

2.5

Vertical displacement (mm)

3.0

3.5

Figure 7: The relationship of vertical displacement and normal stress in Case 1
and Case 2
The influence of cyclic loading involving the direction is apparently different. In
one-dimensional loading condition, especially the cyclic loading was verticallyoriented; the magnitude of normal stress and displacement in lateral direction

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should be lesser than the other way. This expectation was proved when plotting
the horizontal displacement against the normal stress (LC3 and LC7)
The Figure 8 presents the comparison in Case 1 and Case 2 in horizontal direction.
In spite of the smaller magnitude than in vertical condition, the denser backfill
still shows the lesser displacement and normal stress acting on the pipe.
Case 1 - Loose

LC3
LC7

Normal stress (kPa)

60
50
40
30
20
10
0

Case 2 - Dense
60

45

30

15

0
-2.5

-2.0

-1.5

-1.0

-0.5

0.0

Horizonatal displacement (mm)Figure 8: The relationship of horizontal displacement and normal stress in Case 1
and Case 2

Figure 9: Bending strain in 100th cycle
Besides load-cells attached on the pipe, there are 16 strain gauges mounted insideand outside which reported the bending strain. Bending strain provides how muchthe pipe is bent by averaging the difference of inner and outer strain. Figure 9shows the bending strain in Case 1 and Case 2 in the last cycle of loading.
The deformation of flexible pipe buried in soil with different degree of compaction
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Bending strain in the last 100th cycle in Case 1 is greatly larger than in Case 2,
which means that in loose sand, the pipe is much easier to deform than in thedense case, while in Case 2 there is a slightly different in two parameters. The
model pipe also has intention to deform in lateral direction, expressing in larger
magnitude at location number 3 and 7. This result once again confirms theimportance of the backfill compaction to the pipe behavior.
3.3 Effect of cyclic loading
The effect of cyclic loading is clarified by plotting the normal stress against theelapsing time. In loose backfill (Case 1) the vertical stress decreased, meanwhile
the horizontal stress increases when raising the loading number. Reversely, for thedenser backfill Case 2 expressed the same behavior with the slightly change inboth vertical and horizontal stress. In another hand, for Case 3, the normal stressat locations except number 5 exhibited the same behavior with Case 2. At location
5, the normal stress increased gradually. Figure 10 presents the relationship ofelapsing time and normal stress in all locations in three cases.

Figure 10: The relationship of elapsing time and normal stressDue to the confinement in Case 2, normal stress according to elapsing time did
not change much. However, as mentioned above, the Case 3 had no stableboundary, the movement of sand around the pipe also caused the increase innormal stress.

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3. CONCLUSION
The results of a series of experiment achieved so far have confirmed the role ofcompaction to the pipe behavior.
1, The dense of backfill influence on the ground surface settlement as well as thedisplacement of the pipe subjected to different direction. The denser the backfill iscompacted, the lesser the magnitude of settlement and deformation of buried pipeachieve.
2, The bending strain in the dense backfill is much smaller than in the loose case.
3, When the buried pipe experiences the cyclic loading, the normal stress acting invertical orientation gradually reduces while horizontal normal stress increases
progressively in loose backfill. On contrary, in dense backfill compaction thenormal stress in both horizontal and vertical direction does not change much.
4, The buried pipe when the backfill soil is improved around shows the same
behavior to the dense case, however because of the unstable boundary also theeffect of cyclic loading, the settlement of footing surface is still large.

REFERENCES
Ko, Donghee, 2010. Behavior of flexible liner in buried double-layered pipe bytrenchless renewal. Doctor Thesis, The University of Tokyo.
Clarke, N.W.B, 1968. Buried pipelines – A manual of structural design andinstallation. Maclaren And Sons London.
Plastic
Pipe
Institute.
Handbook
of
PE
Pipe.
http://plasticpipe.org/publications/pe_handbook.html

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Triaxial test for the evaluationof internal erosion
Mari SATO1, Reiko KUWANO2
1

Ph.D Student, Dept. of Civil Engineering,
Faculty of Engineering, the University of Tokyo, Japanmsato@iis.u-tokyo.ac.jp
2
Professor, ICUS, IIS, the University of Tokyo, Japan

ABSTRACTInternal erosion is the phenomenon washing fine particles out of the ground. It
causes various ground disaster such as cave-in accidents and landslides, thoseare supposed to happen due to water penetration into the ground with rainfalls.
Underground water penetration is sometimes concentrated at a certain area suchas a boundary of fill and original ground, and surroundings of undergroundstructures. Therefore it is considered that internal erosion repeatedly occurs
peculiar areas with rainfalls, but influence of repetition of internal erosion on themechanical properties of soil is not well understood.
In this research, new triaxial test apparatus was setup for the evaluation of theinfluence of internal erosion on the soil. A pedestal of the triaxial apparatus had
small holes which allow soil particles outflow when applying high hydraulicgradient. In addition, soil stiffness was measured by cyclic loadings.
Keywords: internal erosion, landslides, cave-in accident, triaxial test１
1. INTRODUCTION
Many ground disasters are caused by underground water flow1). Water flow
sometimes concentrates at the gaps between original fills and buried fills, whereinternal erosion happens. Internal erosion was a phenomena of soil particle loss
inside the ground through water flow. Large amount of internal erosion caused
collapse of the ground, which had been studied mainly about rock-fill dams. On
the other hand, small amount of internal erosion had not been studied so much. It
supposed to occur repeatedly by rainfall but the influence of small amount ofinternal erosion on the ground was not clarified.
In this study, triaxial test apparatus for internal erosion was installed forevaluating influence of internal erosion on soil stiffness and deformation.

2. TEST APPARATUS AND PROCEDURE
Schematically figure was shown in Figure 1 and picture was shown in Figure2.
The bottom and upper plate of the apparatus had many holes as shown in Figure 3.
Each hole’s diameter was 5mm. Soil specimen’s size was 160mm height and 75733

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2013, Hanoi,
Vietnammm diameter. 3 LDTs and 3 Clip gages were adapted.(Referring to Figure 4) LDT
was for vertical displacement and Clip gage was for radial displacement. EDT
was put outside the specimen, which was not accurate such as LDT and Clip gage
but had longer ranges than those. The position of LDTs and Clip gages on thespecimen was shown in Figure 4.
Test procedure was shown as below. First, mesh paper which was changed by
the test conditions (Referring to chapter 2) was put on the bottom plate and below
the upper plate. Then specimen was compacted under the optimum water content(around 14%). Specimen was kept on 25kPa confining compression stress puttingby cell pressure, which was monitored by HCDPT. Inside the specimen was kept
on atmospheric pressure. LDTs and Clip gages were fixed like Figure 4. After the
specimen preparation, Water was infiltrated from an outside water tank,simulating the condition under the ground under water level. After water
infiltration, 2 water tanks were connected to the specimen like Figure 1. One wasconnected to the top of the specimen and the other was connected to the bottom of
the specimen. In this paper, one was called “upper water tank” and the other wascalled “bottom water tank”. -75kPa, negative pressure was put on the bottom tankfor making downward water flow from upper tank to the bottom tank. Upper
water tank was released to the atmospheric condition during the downward water
flow. Load cell was put to each water tank, which the change of the weight of thetank was measured. Mesh paper controlled the amount of internal erosion by
downward water flow. Weight of soil loss and turbidity of drained water wasmeasured. Turbidimeter was 2100P, made by Ⓒ Hach, which applied
nupherometory method. Turbidity was represented by the unit “NTU”. Larger
value meant water got cloudier. (Referring to Figure 5
After the downward water flow, the specimen was sheared with 0.06%/min withdrained condition. During the test, 0.002% vertical strain of 11 times cyclicloading was carried out 3 times:1) after the preparation of the specimen 2) after
the water infiltration 3) after the downward water flow to measure the Young’s
Modulus and Poisson’s ratio.(Reffering to Figure 6)

3. TEST CONDITIONS
Figure 1. Schematic figure of test apparatus

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Figure 2. Photo of
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Figure 3 The bottom plate of test apparatus

Figure 4. LDT and Clipgage (left: photo, right: position)

Figure 5. Turbidimeter(left) and sample cells(right)

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VietnamFigure 6 Schematic figure of test procedure

2. TEST CONDITIONSAll experimental conditions were shown in Table 1. Test material was Edosaki
sand (ρdmax=1.76g/cm3 , Wopt=14.2%, ρs=2.705g/cm3, emin= 0.868, emax =1.383) and particle size distribution of that was shown in Figure 7. From Figure 7,
Edosaki sand was “unstable material” which was suggested by Kenny et al.
(1985)2). Dc (Compaction Degree) was a value before downward water flow,which was estimated from initial condition and deformation during water
infiltration.
5 different kinds of mesh paper were applied; filter paper, cloth, 1mm meshpaper, 0.05mm mesh paper and holes of filter paper. Filter paper and cloth
prevented almost all internal erosion. Especially filter paper prevented internal
erosion completely. 1mm mesh paper and 0.05mm mesh paper caused someamount of erosion. The amount was larger in 1mm mesh. 0.05mm mesh paper
only made fine particles’ erosion. 2 holes were made in the filter paper mean
“2holes”. Each hole’s size was 5mm diameter. This condition caused internal
erosion easiest.
The amount of inflow water was changed in some test conditions. Twice and 5
times means twice or 5 times amount of water was flowed down as other test
conditions’ (around 1.5L)
Table 1. Test conditions

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Code

Soil loss(%)

Turbidity

Soil loss

Dc

1mm212

0.18

580

Small

86.7%

0.05mm217

0.06

328

Small

85.8%

filterpaper227

0

1.92

Limited85.8%

twice305

0.4

862

Small

85.5%

4times509

0.61

1265

Large

86.2%

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rosi5240

8.65

Limited85.2%

1mm610

0.21

598

Small

83.8%

2holes619

0.993

1500

Large

85.2%

2holes630

0.873

1140.3

Large

84.9%

cloth703

0.03

141

Limited85.3%

cloth708053Limited86.4%

Figure 7. Particle size distribution of Edosaki sand

3. TEST RESULTS
3.1 Turbidity and weight of eroded soil
Turbidity and weight of eroded soil of all test conditions were shown in Table 1.
In twice of 5 times test cases turbidity was the sum of each bottom tank’s turbidity
value. Weight of eroded soil was in dry condition. Test result was separated from3 types depending on weight of eroded soil; limited (almost no) erosion case,small erosion case and large erosion case.
Relationships between turbidity and weight of eroded soil were shown in Figure 8.
Weight of eroded soil was proportionate to turbidity, which was consent to Sato etal.(2012)3) mentioned.

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October
2013, Hanoi,
VietnamFigure 8. Relationships between weight of eroded soil and turbidity

3.2 Stress-Strain Curve
Stress-Strain curve of all test cases was revealed in Figure 9. For calculating ofshear stress, cross-sectional area of the specimen was measured from Clipgages’
data by around 5% of axial strain and then estimated from EDT’s data (Poisson’s
ratio=0.2) Figure 9 revealed that residual stress was not so changed in all test
conditions. On the other hand, large erosion case and limited erosion case of filter
paper was compared in Figure 10. Figure 10 suggested that around 10%
difference of peak stress. The reason why peak stress of cloth case was weaker
than that of filter paper but one possibility was cloth was deformed during
shearing.
Figure 12 represented relationships between turbidity and ratio of q at eachpeculiar small axial strain: 1%, 2%, 3%, 4% and 5%. Value 1 of Ratio of q was
calculated from average q of filter paper test cases. From Figure 12, it was
supposed that q decreased most due to increasing of turbidity in 1% axial strain.
Then an relationships between turbidity and decreasing of ratio of q was stablefrom 2% to 4%. At 5%, Ratio of q didn’t decreased so much by rise of turbidity. It
was suggested that influence of erosion disappeared by increasing of shear stress.
Finally influence vanished completely and residual stress were similar in all test
conditions.

Figure 9. Stress-Strain curve of all test conditions

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Figure 10. Details of Stress-Strain curve

Figure 11. Turbidity and decreasing of shear stress

3.3 Young’s Modulus and Poisson’s Ratio
Young’s modulus was calculated by Eq.1.
E=∆σ 1∆ε axial∆σ 1 = range of axial stressEq.1∆ε axial = range of axial strain

Axial stress was measured from the load cell and axial strain was measured from
4 LDTs during cyclic loading.
Poisson’s ratio was calculated by Eq.2.

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October
2013, Hanoi,
VietnamE=∆ε radial∆ε axial

Eq.2

Cyclic loading was repeated 11 times and 10th cycle was applied to calculate
Young’s Modulus and Poisson’s Ratio.
Result of Young’s Modulus was shown in Figure12. Vertical axis was a change
ratio of Young’s Modulus from previous condition. Limited erosion case wasplotted in right of Figure 12. Small and large erosion cases were plotted in left of
Figure 12. By comparing left and right of Figure12, it was suggested that
decreasing tendency by water infiltration was similar in both cases. However,
only small and large erosion test cases caused decreasing of Young’s Modulus by
downward water flow, which was influence of internal erosion.
Result of Poisson’s ratio was shown in Figure 13. Clip gage’s data had noises
and not so accurate as LDT’s. It was failed to get collects data of Clip gages insome test conditions. Poisson’s ratio was not so changed during the test. The
average value was around 0.2, which was applied for calculating σ(Referring to
3.2).

Figure 12. Change of Young's Modulus(right: limited erosion, left: small&large erosion)

Figure 13. Change of Poission's Ratio

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4. DISCUSSION AND CONCLUSION
� Erosion caused decreasing of mobilized deviator stress, which disappearedby increasing of axial strain. Probably because during shearing andconsolidation, small voids created by internal erosion vanished assuggested by(Samanthi et al.(2011)4).
� Young’s modulus decreased by erosion but Poisson’s ratio did notsimilarly change. It seemed to be affected by the direction of water flow.
� Maeda et al.(2012)5) simulated effect of particle loss on soil stiffness by
DEM. Tendency of the simulation was similar as our test result. Theysuggested small particle movement for long distance through connectedvoids in the ground was difficult. In this research, large holes at the bottomcaused erosion easily. Therefore, large particles’ unstable conditions anddrainage changed particle structure inside the specimen. Then small
particle moved out easily from the soil.
� For evaluating degree of erosion, turbidity of the drained water can be canbe a good indicator..
� In the ground, repetition of small erosion maybe caused deterioration of
the soil structure. If it has some loosened part or cracks like gaps of theburied structures (Sato et al.(2011)6) and (2012)7)) , water flow concentrate
there and high water pressure may be generated, which made internal
erosion easily and sometimes made soil pipes.

REFERENCES
1) Sato, M. & Kuwano, R. Model Tests for the Evaluation of Formation andExpansion of a Cavity in the ground. Proc. of the 7th International Conference on
Physical Modelling in Geotechnics 2010. Zurich, June 2010, pp.581-586
2) Kenny,T.C.,Lau.D. (1985). Internal Stability of granular filters. Canadian
Geotechnical Jornal Volume 22:215-225
3) Sato,M. and Kuwano,R. “Evaluation of internal erosion by turbidity of drainedwater”, Proc. of 11th International Symposium on New Technologies for Urban
Safety of Mega Cities in Asia, No.23, Ulaanbaatar, Mongolia, October 2012.
4) Renuka,S. & Kuwano,R. “Evaluation of ground loosening behavior andmechanical properties of loosened sand associated with underground cavities”,
master thesis of the Department of Civil Engineering, the University of Tokyo,
September 2012
5) Maeda.K, Wood.D.M, and Kondo, A. Micro and macro modelling of internal
erosion and scoring wih fine particle dynamics, Proc. of 6th International
Conference on Scour and Erosion. 2012, Paris, France: ISCE-000197
6) Sato,M. and Kuwano,R. “Influence of Underground Structures on Cavity
Formation”, Proc. of 10th International Symposium on New Technologies for
Urban Safety of Mega Cities in Asia, Session11-4, Chiang-Mai, Thailand,
October 2011.
7) Sato,M. and Kuwano,R. “Influence of underground structures on cavity
formation due to various conditions of water flow”, Proc. of 2nd International
Conference on Transportation Geotechnics, pp.617-622, Hokkaido,
Japan ,September 2012.

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A study of bored pile bearing capacities atsome locations in Hanoi, Vietnam
Thuy Diep DUONG1, Hung Quang PHAM2, Hieu Duc KIM3, Lam Thai GIANG4
1
Master of Science, University of Civil Engineering, Hanoi, Vietnam
thuyxd0582@gmail.com
2
Associate Professor, University of Civil Engineering, Hanoi, Vietnam
3
Engineer, Geotechincal and Construction Engineering Institute, Hanoi, Vietnam
4
Master of Science, University of Civil Engineering, Hanoi, Vietnam.
ABSTRACTThe paper presents test results of 06 bored/Barrette pile tests that installed strain
gauges at three locations in Hanoi city. From the t-z and q-z curves obtained fromthe tests, the authors constructed the P-S curves of the piles. The estimated pile
bearing capacity using the Davisson (1972) for each pile were then comparedwith the calculated ones using common equations for calculating bearing capacityof the pile from the soil profile. It is found that the bearing capacity calculated ismuch smaller than the one estimated from the test results. The paper also presents
some suggestions for reasonable lengths of bored piles in gravel layer fordifferent pile diameters and concrete grades at the three locations.
Keywords: Bearing capacity, bored pile, Barrette pile, pile test, suitable length,
Hanoi.
1. INTRODUCTION
Thousands of bored and Barrette piles were built in Vietnam each year. In Hanoi,
a bored/Barrette pile is normally designed with a length in the range from around
40 m to 80 m and pile toe is usually in the gravel or stone layer. Bored pile
diameter is from 0.8 m to 2.5 m with allowable bearing capacity in the range fromround 500 to 3,500 tons.
1 North Thang Long

2 Thanh Xuan

3 Ha Dong

Figure 1. Three locations of the test piles in Hanoi city (Google, 2013)743

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamWhen applying common equations in standards for calculating bored/Barrette pile
bearing capacity in Hanoi city, toe bearing is around 30% to 60% bearing capacityof the pile. There is a fact that thick mud layers are usually found at toes of most
cast-in-place piles. However, pile load test results show that most of designs are
acceptable or even over design (Vu and Pham, 2010; Trinh, 2011; Bui and
Nguyen, 2011). It means that the applied equations may not be appropriate for thesoils in Hanoi city. Therefore, further study on the bearing capacity ofbored/Barrette pile in Hanoi city is very necessary.
In this paper the author used load test results of 06 piles which used strain gauges
along the piles in three locations (North Thang Long Urban area, Thanh Xuan
District and Ha Dong District) to study the actual shaft and tip bearing capacity.
In details, the author analyzed the test results to: 1) find the (t-z) curve knowing as
the curve presents the relationship between the unit shaft friction versus therelative movement between the pile shaft and the soil and the (p-z) curve knowing
as the curve presents the pile end bearing unit versus the pile toe movement; and2) reconstructed the axial compression curve (P – S). The pile bearing capacities
with different lengths and sizes are estimated from the P-S curves using Davisson(1972) method. Pile bearing capacity estimated is then compared with the pile
bearing capacities calculated using some common equations in standards(Japaness standard; Meyerhoff, 1956 and FHWA, 2006). Also, a suggestion forreasonable lengths for different pile diameters and locations are presented.
2. THEORY
2.1 Construct the axial static load test curve (P-S)
P0

0

0
t–z

1

Load (tons)

dh

P1
Pi
t–z

t–z

p–z

i

i

Straingauges

Pi+1

S

…..

…

i

P

Settlement (mm)

P

Pn

n

n

n

Pile toea) t-z and p-z curves ofsoil layers

Ptb) Pile segmentc) P-S curve

Figure 2. Construction of the pile axial compression test curve (P-S)
From the static load test for bored pile with strain gauges installed, the t-z curves
and p-z curves for soils could be obtained (Hayes and Simmonds, 2002; Vu and744

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Pham, 2010 and Duong et al., 2013). The P-S curve could be reconstructed fromthe t-z and p-z curve by dividing the pile into multiple small segments with alength of dh. The load on top of the pile segment #i could be calculated as follows:
Pi = Pi+1 + Fi
(1)
where: Fi = total shaft friction of the pile segment.
By assuming a small movement of the pile toe, S0. From the p-z, the end bearingof the pile, Pt, could be calculated as follows:
Pt = pt . A(2)where: pt = unit end bearing resistance and A = pile cross section area.
Total shaft friction in a pile segment #i could be calculated as follows:
Fi = ti.u.dh(3)
where: u = perimeter of the pile, dh = length of the pile segment and ti =unit shaft friction of the pile segment equivalent with the movement.
Elastic deformation, Si, of the pile segment #i could be calculated as follows:Si= (Pi+Pi+1).dh/(2EA)(4)
where: Pi and Pi+1 are axial forces at the top and bottom of the pilesegment, dh = length of the pile segment, A = pile cross section area and E= elastic modulus of the pile material.
Using the above method to calculate the elastic deformation of pile and the axial
force at the top of the pile, the P-S curve could be constructed.
2.2 Estimate the pile bearing capacity using Davisson (1972)
Davisson (1972) method is introduced in the Vietnamese standard and widelyused for estimating pile bearing capacity. In this method, the ultimate pile bearing
capacity is the load value that equivalents with the following pile settlement:PLD 0.0038 
( m)
EA
120

(5)

where: P = pile load, L = pile length, A = pile cross section area, E =material elastic modulus, D = pile diameter.
2.3 Pile structure bearing capacity
In Vietnam, beside the Vietnamese standards, other international standards could
be used with acceptance of the owner. In the Vietnamese standard TCXD 1951997, the pile structure bearing capacity could be calculated as follows:P  Ru .Ac  Ra . As
(6)
where: Ru  strength of the concrete. For bored pile, Ru  R / 4.5 but notover 60 kG/cm2. Ra  strength of steel (for rebar diameter less than 28mm) and Ra  Rc / 1.5 (for rebar lager than 28 mm) but not over 2,200
kG/cm2. Ac = concrete area and As = steel area.
For the International Building Code (IBC-2009), the pile structure bearing
capacity could be calculated as follows:P  0.25 f c'. Ac  0.4 f s .As(6)where: f '  strength of the concrete; f  yield stress of the steel; A cconcrete area; As  steel area.

s

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2.4. Estimating the suitable length of piles
Based on the reconstructed P-S curve and the Davisson (1972) method as
described above, bearing capacity of bored piles with different pile lengths andpile diameters at three locations in Hanoi were estimated. The authors suggested
reasonable lengths for different bored pile diameters in the three locations bycomparing pile bearing capacity estimated using the above method and thestructure bearing capacity of the pile. The reasonable length is the length thatbearing capacity of the structure is approximately equal to the bearing capacity
estimated for the soil.
3. TESTING PROGRAM
3.1 Pile tests at North Thang Long areaa) Introduction

The first research location is in the North Thang Long urban area, Tay Ho district,Hanoi. The depth of the gravel layer is from -40 m compared with the groundsurface. This area has 7 soil layers and gravel is the 7th layer with N-value fromthe SPT greater than 80. Detailed description of the soil profile is shown in Figure3.
b) Description of the test piles

Two test piles in this area: 1) Barrette P1 with a size of 1.0 x 2.8 (m) and a lengthof 45 m; and 2) Bored pile P2 with diameter of 2.0 m and a length of 57.2 m. The
Geokon model #4911 strain gauges were installed in both piles at 7 levels withfrom 2 to 4 gauges at each level (Loadtest, 2011). Locations of the strain gauges
are presented in Figure 3.

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ICUS Report 73a) Barrette pile P1b) Bored pile P2

Figure 3. Soil profile and strain gauges levels for test piles in North Thang Longurban areac) Test results
Analyzing the test results, the t-z and p-z curves for each soil layer could beobtained and presented in Figures 4 and 5.
Mobilized net unit side shear (kPa)

600
500
Very dense sandy to gravel

400

Very dense gravel and cobbles

300

Medium dense to dense sandy clay
Stiff to very stiff clay of low plastic

200

Stiff to very soft sandy clay

100
0
0

4

8
12
16
20
24
Average Shear Zone Displacement (mm)28

32

Figure 4. Mobilized unit shaft friction for soils at the North Thang Long urban
area

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Mobilized unit end Bearing (kPa)

4500
4000
3500
3000
2500
2000
1500
1000
500
0
0

10

20

30

40
50
60
70
Displacement (mm)

80

90

100

110

120

130

Figure 5. Mobilized end bearing for the gravel soil at the North Thang Long urban
area (layer #7)d) Estimating pile bearing capacities

From the t-z and p-z curves of soils at the testing location, the P-S curve isconstructed. Using the Davisson (1972) method, the pile bearing capacity could
be constructed (Figure 6).
Load P(T)
0

1000

2000

3000

4000

5000

6000

7000

0
10

Settlement (mm)

20
30
40
50

Davisson (1972)

60
70
80

Figure 6. P-S curve and estimation of bearing capacity using Davisson method fora bored pile with diameter of 2.0 m and length of pile in the gravel layer is 4.0 m
By changing the diameter as well as the length of the pile in the gravel layer,
corresponding pile bearing capacity could be obtained using the above method.
Figures 7 to 9 present pile bearing capacities calculated using common equations
based on the soil profile and estimated using Davisson (1972) methods for boredpile with diameter of 1.0, 1.5, and 2.0 (m) at various lengths in the gravel layer. In
each figure, the structure pile bearing capacity is also presented for 1) Vietnamesestandard (TCXD) and 2) International Building Code (IBC).

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Load P(T)
400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

Length of pile in gravel (m)2Davission (Fs=2)
4

Jananess (Fs=3)
Meyerhoff (Fs=3)

6

FHWA (Fs=2)

IBC

8
10
12

TCXD

14

Figure 7. Comparison between the estimated bearing capacities using Davisson(1972) method and calculated values using soil profile for bored pile D1000(diameter of 1.0 m at various depth in gravel layer)
Load P(T)
500

1000

1500

2000

2500

3000

3500

4000

Length of pile in gravel (m)2Davission (Fs=2)

4

Jananess (Fs=3)

6

Meyerhoff (Fs=3)
IBC

8

FHWA (Fs=2)

10
12

TCXD

14
16
18

Figure 8. Comparison between the estimated bearing capacities using Davisson(1972) method and calculated values using soil profile for bored pile D1500(diameter of 1.5 m at various depths in gravel layer)

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Load P(T)

Length of pile in gravel (m)

1000
2

1500

2000

4

2500

3000

3500

4000

4500

5000

TCXD

5500

6000

Davission (Fs=2)
Jananess (Fs=3)

6

Meyerhoff (Fs=3)8

FHWA (Fs=2)

IBC

10
12
14
16
18

Figure 9. Comparison between the estimated bearing capacities using Davisson(1972) method and calculated values using soil profile for bored pile D2000(diameter of 2.0 m at various depths in gravel layer)
Table 1. Reasonable length of pile in gravel layer for various pile diameters andconcrete grades for North Thang Long area.
Pile D1000
Pile
structure
bearing
capacity

IBC
TCVN

Factorofsafety

Fs=2
Fs=3
Fs=2
Fs=3

Pile D1500

Concrete
B40

Concrete
B45

Concrete
B40

P
(T)

P
(T)

P (T)

745
553

Ls
(m)
<2
<2
<2
<2

822
605

Ls
(m)
<2
<2
<2
<2

1,668
1,234

Ls
(m)
<2
5
<2
3

Pile D2000

Concrete
B45
P (T)
1,843
1,350

Ls
(m)
<2
7
<2
5

Concrete
B40
P (T)
2,984
2,220

Ls
(m)
3
11
<2
5

Concrete B45
P (T)
3,295
2,427

Ls
(m)
4
14
3
7

Note: P is the pile structure bearing capacity determined using the two standards with assumptionthat the rebar area is 1.0% of the cross section. Fs is the factor of safety for pile bearing capacity
determined using the Davisson (1972) method. Ls is the length of the pile in the gravel layer that
results in the bearing capacity for soil structure is approximately equal to the one estimated using
the Davisson (1972) method.

3.2. Pile test at Thanh Xuan areaa) Introduction

The second pile test was at the Thanh Xuan district, Hanoi city. The gravel layer
exists from the depth of -48 m from the ground surface. There are 18 soil layers
and the 18th layer is the dense gravel with N-value from the SPT test is over 100.
This layer appears to be very thick (Figure 10).
b) Description of the test pile

There are two test piles: 1) Barrette pile (TP3) with a size of 1.2 x7.0 (m) and a
depth from -0.9 m to -50.45 m, and 2) Barrette T shape pile (TP4) with a size of750

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2.8mx4m and a depth from -0.9 m to -49.45 m. Each pile has 24 strain gauges
installed at 4 levels (Figure 10).

a) Barrette pile TP3b) Barrette T-shape pile TP4

Figure 10. Soil profile and strain gauges levels for test piles in Thanh Xuan areac) Test results and estimation of pile bearing capacity

The authors analyzed the test results as in the North Thang Long urban area
(Loadtest, 2008). The pile bearing capacities calculated using common equations
based on the soil profile and estimated using Davisson (1972) methods for boredpile with diameter of 1.0, 1.5, and 2.0 m with various lengths in the gravel layer
are presented in Figures 11 to 13.
Load P(T)

Length of pile in gravel (m)

300

600

900

1200

1500

1800

2100

2400

2700

2
4

IBC

6
8

Davission (Fs=2)
Jananess (Fs=3)
Meyerhoff (Fs=3)

TCXD

FHWA (Fs=2)

10
12
14
16

Figure 11. Comparison between the estimated bearing capacities using Davisson(1972) method and calculated values using soil profile for bored pile D1000(diameter of 1.0 m at various depths in gravel layer)

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Load P(T)
500

1000

1500

2000

2500

3000

3500

4000

2
Davission (Fs=2)

Length of pile in gravel (m)4Jananess (Fs=3)

6

Meyerhoff (Fs=3)8

FHWA (Fs=2)

10
IBC

12
TCXD

14
16

Figure 12. Comparison between the estimated bearing capacities using Davisson(1972) method and calculated values using soil profile for bored pile D1500(diameter of 1.5 m at various depths in gravel layer)

Length of pile in gravel (m)Load P(T)
1000
2

1500

2000

2500

3000

3500

4000

4500

TCXD

4

5000

5500

Davission (Fs=2)
Jananess (Fs=3)

6

Meyerhoff (Fs=3)
FHWA (Fs=2)

8

IBC

10
12
14
16

Figure 13. Comparison between the estimated bearing capacities using Davisson(1972) method and calculated values using soil profile for bored pile D2000(diameter of 2.0 m at various depths in gravel layer)
Table 2. Reasonable length of pile in gravel layer for various pile diameters andconcrete grades for Thanh Xuan area
Pile
structure
bearing
capacity
IBC
TCVN

Factorofsafety
Fs=2
Fs=3
Fs=2
Fs=3

D1000
B40
P
(T)
745
553

Ls
(m)
<2
<2
<2
<2

D1500
B45

P
(T)
822
605

B40

Ls
(m)
<2
3
<2
<2

P (T)
1,668
1,234

D2000
B45

Ls
(m)
<2
7
<2
<2

P (T)
1,843
1,350

B40
Ls
(m)
<2
9
<2
3

P (T)
2,984
2,220

B45
Ls
(m)
3.5

11.5
<2
5.5

P (T)
3,295
2,427

Ls
(m)
5.5
14
<2
7

Note: P is the pile structure bearing capacity determined using the two standards with assumptionthat the rebar area is 1.0% of the cross section. Fs is the factor of safety for pile bearing capacity

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determined using the Davisson (1972) method. Ls is the length of the pile in the gravel layer that
results in the bearing capacity for soil structure is approximately equal to the one estimated using
the Davisson (1972) method.

3.3 Pile test at Van Khe, Ha Dong areaa) Introduction

The third pile test location was at the Ha Dong district, Hanoi city. The gravel
layer exists from the depth of -41 m from the ground surface. There are 7 soil
layers and the 7th layer is gravel and coarse sand at very dense state with N-value
from the SPT test is over 100. This layer appears to be very thick (Figure 13).
b) Description of test piles

There are two piles were tested at this location (Loadtest, 2009): 1) Bored pile
TP5 having diameter of 1.5 m at the depth of -10.5 m to -66.55 m and 2) Boredpile TP6 having diameter of 2.0m from the depth of -9.1 m to -51.15 m (Figure14)a) Bored pile TP5b) Bored pile TP6

Figure 14. Soil profile and strain gauges levels for test piles in Ha Dong areac) Test results and estimation of pile bearing capacity

Similar to the other pile test location, the pile bearing capacities calculated using
common equations based on the soil profile and estimated using Davisson (1972)
methods for bored pile with diameter of 1.0, 1.5, and 2.0 m at various depths in
the gravel layer are presented in Figure 15.

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capacities
some locations
in locations
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Load P(T)
500

700

900

1100

1300

1500

1700

1900

2100

2300

Depth pile in gravel or stone (m)24D1000 (Fs=2)

6

D1500 (Fs=2)

8

D2000 (Fs=2)

10
12
14
16
18

Figure 15. Estimated bearing capacities using Davisson (1972) method for boredpile D1000, D1500 and D2000 (diameter of 1.0; 1.5; 2.0 m at various depths ingravel layer)
Table 3. Reasonable length of pile in gravel layer for various pile diameters andconcrete grades for Ha Dong area
Pile
structure
bearing
capacity
IBC
TCVN

FactorofsafetyFs=2
Fs=2.5
Fs=2
Fs=2.5

D1000
B30
P
(T)
589
467

D1500
B35

Ls
(m)
<2
4
<2
<2

P
(T)
667
510

Ls
(m)
<2
9.5
<2
<2

B30
P (T)
1,328
1,054

D2000
B35

Ls
(m)
11.5
>20
<2
11

P (T)
1,503
1,151

B30
Ls
(m)
18
>20
5
16

P (T)
2,361
1,873

B35
Ls
(m)
>20
>20
13
>20

P (T)
2,672
2,046

Ls
(m)
>20
>20
18
>20

Note: P is the pile structure bearing capacity determined using the two standards with assumptionthat the rebar area is 1.0% of the cross section. Fs is the factor of safety for pile bearing capacity
determined using the Davisson (1972) method. Ls is the length of the pile in the gravel layer that
results in the bearing capacity for soil structure is approximately equala to the one estimatedusing the Davisson (1972) method.

3.4. Comments on the test results:

Pile bearing capacity is increased significantly when increasing the length ofbored pile in the gravel layer in the all three locations. The calculation results
showed that the pile bearing capacity calculated using some common equations
are significantly less than the value estimated from the P-S curve using theDavisson (1972) method. By comparing the structure bearing capacity and the one
estimated from the P-S curve, reasonable length of bore pile could be estimated aspresented in the Tables 1 to 3.
For all three locations in Hanoi city, it was found that the length of bored pile
D1000 in the gravel layer should be from 2.0 to 3.0 m. For the D1500 bored pile,the length of pile in the gravel layer should be from 3 to 9 m depending on theconcrete grade as well as the selected factor of safety. For the D2000 pile,reasonable length of the pile in the gravel layer is in a range from 5 to over 20 m.

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The test results also show that the soil profiles are quite different between thethree locations.
4. CONCLUSIONS

Some conclusions could be drawn from the research as follows:
1. The test results of a pile load test that installed strain gauges could provide
the useful information that could be used to: 1) estimate the shaft firction andend bearing capacity of the pile and 2) estimate bearing capacity of otherbored piles with different diamaters and lengths at the same location.
2. The prediction of the pile bearing capacity using common equations aremuch less than the one estimated from the P-S curve using the Davisson(1972) method.
3. Resonable lengths of bored piles with different diamters in the threelocations have been presented. These values could be used as references for
future projects with an attempt to have cost-effective foundation designs.
REFERENCESBùi Đức Hải và Nguyễn Bảo Việt, 2011. Thí nghiệm nén tĩnh cọc có kết hợp đobiến dạng dọc thân cọc - một phương pháp nâng cao độ chính xác khi xác địnhsức chịu tải của cọc khoan nhồi và cọc barrete ở Hà Nội. Tạp chí Khoa học kỹthuật Mỏ - Địa chất. Số 35 – 7/2011;Dương Diệp Thúy, Phạm Quang Hưng và Kim Đức Hiếu, 2013. So sánh sức
kháng ma sát thành của cọc đổ tại chỗ giữa một số phương pháp tính thường
dùng và kết quả thí nghiệm cho nền đất tại khu vực Bắc Thăng Long Hà Nội. Hộithảo khoa học Hạ tầng giao thông Việt Nam với phát triển bền vững, TISDV 2013.
FHWA, 2006. Design and Construction of pile foundation, U.S. Department ofTransportation, National Highway Institute, April 2006;
Hayes, J. and Simmonds, T., 2002. Interpreting strain measurements from load
tests in bored piles, Proceedings, Ninth International Conference on Piling andDeep Foundations, DFI, Nice, France;
International Building Code (IBC), 2009;
Loadtest, 2008. Report on Barrette pile load testing, LTI-2612-1, Deep
Foundation Testing, Equipment & Services.
Loadtest, 2008. Report on Barrette pile load testing, LTI-2612-2, Deep
Foundation Testing, Equipment & Services;
Loadtest, 2009. Report on drilled pile load testing (Osterberg method), LTI-26191, Deep Foundation Testing, Equipment & Services;
Loadtest (2009). Report on drilled pile load testing (Osterberg method), LTI2619-2, Deep Foundation Testing, Equipment & Services;
Loadtest, 2011. Report on Barrette pile load testing, LTI-2880-2, Deep
Foundation Testing, Equipment & Services;
Loadtest, 2011. Report on Bored pile load testing, LTI-2895-1, Deep Foundation
Testing, Equipment & Services;
TCXD 205:1998. Móng cọc – Tiêu chuẩn thiết kế, Nhà xuất bản xây dựng;TCXD VN 269:2002. Cọc – Phương pháp thí nghiệm bằng tải trọng tĩnh ép dọc

A study of bored
pileofbearing
capacities
some locations
in locations
Hanoi, Vietnam
A studybored pile
bearingatcapacities
at somein Hanoi, Vietnam755

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamtrục, Nhà xuất bản xây dựng;Trịnh Việt Cường, 2011. Một số kết quả bước đầu từ thí nghiệm nén tĩnh cọc có
gắn thiết bị quan trắc tải trọng dọc thân cọc ở khu vực Hà Nội. Tạp chí khoa họckỹ thuật Mỏ - Địa chất – Số 25- 7/2011;
Vũ Thanh Hải và Pham Quang Hưng, 2010. Xác định sức kháng ma sát đơn vịdọc thân cọc qua thí nghiệm đo biến dạng dọc trục. Tạp chí Xây dựng, Bộ xâydựng, số 7 năm 2010, trang 50-53.

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A technique of image processing analysis
recommended for research of laterally loaded
pile using a system of X-ray CT scanner
1

Khoa Dang PHAM1, Jun OTANI2
Ph.D., National University of Civil Engineering, Ha Noi, Viet Nam
phamdangkhoa@nuce.edu.vn
2
Professor, Kumamoto University, Japan

ABSTRACT
Geotechnical engineering researches are indispensable for Mega cities design inAsia. Especially, in study of laterally loaded pile, investigation of soil behavior isimportant for evaluating lateral bearing capacity of pile foundation.
The purpose of this research is to develop a technique of image processing
analysis for simulating 3 dimensional (3-D) behavior of soil due to lateral pileloading using a system of X-ray CT scanner. Lateral pile loading tests wereconducted with a soil box and a loading system. A large number of markers weresetup as grids in the soil under the ground surface. After lateral loading wasapplied, CT scanning was conducted on the soil box. From all the CT images
obtained containing images of cross sections of the markers, locations of all themarkers after loading were determined. Thus, a simulation of 3-D movements ofthe markers in the soil was conducted. By connecting the centers of the markers at
the stages before and after loading, the 3-D movements of the markers wereobtained as vectors of the movement, and therefore, the soil behavior due tolateral pile loading was observed precisely in three dimensions.
Finally, 3-D behavior of soil due to lateral pile loading is quantitatively
discussed.
Keywords: mega city, image processing, laterally loaded pile, X-ray CT scanner.

1. INTRODUCTION
Mega cities in Asia are known as big cities on the Earth with population
excess of ten million people. Therefore, safety of mega cities is very important,especially in design of buildings’ pile foundation.
In the field of research on laterally loaded pile, investigation of soil
behavior is indispensable for evaluating lateral bearing capacity of pile foundation.
A number of researches have been done so far on this topic. The pioneer work
done by Broms (1974) obtained the ultimate lateral load applied to the pile headafter discussing the behavior of pile and soil. Reese et al. (1974) also discussed
the ultimate lateral soil resistance based on an assumption of 3-D failure pattern ofsoil. However, it is considered that those researches were proposed not concernedon the real interaction between pile and soil. Thus, precise investigation of actual757

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnambehavior of soil due to lateral pile loading is necessary in order to make morequantitative design calculation.
An X-ray computed tomography (CT) method has been widely used in
medical diagnoses based on the absorption of x-ray beam through materials. Recently, it has become an useful tool for investigating characteristics of soils ingeotechnical engineering (Otani et al. 2000). Results of CT scanning can berealized as the change of density in the material. In this research, a technique ofimage processing analysis for simulating behavior of the soil due to laterally
loaded pile using X-ray CT scanner is developed.
First of all, a model test apparatus, especially for X-ray CT, is introduced.
By using this apparatus, a number of markers (plastic spheres with 2 mmdiameter) are set up in the front of the model pile, where the failure of soil would
occur, at three depths under the ground surface in the soil. Then, lateral pileloading test is carried out with three consecutive loading steps at the pile head. CT
scanning is conducted continuously upward on the soil box from three initial
depths of the markers, after each loading level. Thus, all images of cross sectionsof the markers after their movement in the failure zone of the soil are captured in
the CT images. Based on these CT images, 3-D locations of the markers in thesoil box are determined. Spheres with 2 mm diameter are drawn at those locationsof the markers, and therefore 3-D images of the markers after loading are
simulated. By connecting the centers of the drawn spheres corresponding to thestages before and after loading, the traces of the movements of the markers are
obtained as vectors of movement. Hence, the soil behaviors inside the failure zone
are visualized in three dimensions.
Finally, quantitative discussions are performed on the tendencies of 3-D
movements of some of the markers.

2. SYSTEM OF X-RAY CT SANNER
The system of X-ray CT scanner used in this research is an industrial one.
A photo of the scanner is shown in Figure 1 and its Diagram is shown in Figure 2.

2m

2m

Figure 1. A photo of the system of industrial X-ray CT scanner.

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X-ray Source

Rotation
Specimen
table
Specimen

Detectors

Traverse Stroke: 1100mm

Shield Room

Data Assembling
DeviceImage Data
Processing Device
Workstation

CT table

Mechanical Control Device

Monitor

X-ray Control Device

Keyboard
ConsoleConsoleHigh Voltage Device

Figure 2. Diagram of the industrial X-ray CT scanner.

LoadingsystemModel
pile
Soil box
X-ray
sourceX-ray
Detector

CT table

Figure 3. A photo of testing apparatus.
In this system, collimated x-ray is penetrated all around circumference of a
specimen by rotating and translating of CT table. The detected data is assembled
and cross sectional images are reconstructed using image data processing device
by means of the filtered back-projection method. Then, the image is expressed ona monitor of workstation. By using all these cross sectional images around thecircumference of the specimen, three dimensional images can be reconstructed.

3. TESTING APPARATUS FOR X-RAY CT
Figure 3 shows a photo of testing apparatus in this research, which iscomposed of a soil box and a loading sysem, placed in the system of industrial X-

A techniqueof imageanalysis
processing
analysis recommended
research of laterally loaded
A technique ofimage processing
recommended
for research forof laterally
pile
using
a
systemof
X-rayCT
scannerloaded pile using a system of X-ray CT scanner759

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamray CT scanner (Pham et al. 2004). The lateral loads applied to the pile head
would be conducted under the displacement control.
4. MATERIALS AND TESTING PROCEDURES
4.1 Materials
Toyoura sand was used as the model soil in this test with properties shownin Table 1. Properties of a model pile with rectangular cross section are shown in
Table 2. For the purpose of simulating behavior of soil, a large number of markers(spheres) were placed in the soil. The marker with a diameter of 2 mm was madeby plastic under consideration to be small enough and not to interfere with x-ray,either.
Table 1. Properties of Toyoura sandMaximum dry density (t/m3)
Minimum dry density (t/m3)
Specific gravity
Relative density
(%)

1.66
1.34
2.65
87.0 – 91.0

Table 2. Properties of model pile
Total length of pile
Length of pile in soil
Cross sectional dimension
Material

(mm)
(mm)
(mm)

350
330
20 x 2
Aluminum

4.2 Testing procedures
In this test, the markers were placed at three depths under the groundsurface in the soil. Figure 4 shows a plane view of setup of the markers in each
depth, while Figure 5 shows those three depths at the soil box. Test procedures
can be summarized as follows (7 steps):(1) Model pile was fixed at the tip in the soil box;(2) Sand was prepared into the soil box using multiple sieves to the depth of 70
mm under the ground surface;
Cross section ofmodel pile
4
4
4
4
4
4
4

20

Cross sectionof soil box

4
4
4
4
4
4
4

120

2
25

57 7 7 7 7 7 7 7

unit: mm

120

Figure 4. Plan view of marker setup.

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Lateral load
Levels of setup
of markers

Ground surface
22 46

1
2
3

70

Soil box

330

Model pile
unit: mmFigure 5. Three initial depths of markers.
Model pile

Plastic plate

Model pile

Markers

Sand

Figure 6. . Position device anf initial positions of markers.
(3)
(4)

(5)

(6)
(7)

A plastic plate (position device) was used to set the initial positions of themarkers at this depth, and shown in Figure 6;
Steps (2) and (3) were conducted for the depths of 46 mm and 22 mm under
the ground surface. After markers were installed at 22 mm depth, the sandwas prepared until the level of the ground surface;
Soil box was scanned at three depths of the setup of the markers. It is notedthat the thickness of the x-ray was set to be 1 mm in all process of CT
scanning in the test;
Three consecutive loading steps corresponding to three displacements of thepile head of 5 mm, 10 mm and 15 mm, respectively, were conducted; andAfter each loading step, CT scanning was carried out on the soil box
continuously upward from the depth of 70 mm.

5. RESULTS AND DISCUSSION
5.1 CT images
Figure 7 shows CT images along the pile depth of the model ground at theinitial condition and after three loading levels. It is observed that cross sections of
A techniqueof imageanalysis
processing
analysis recommended
research of laterally loaded
A technique ofimage processing
recommended
for research forof laterally
pile
using
a
systemof
X-rayCT
scannerloaded pile using a system of X-ray CT scanner761

0ctoberVietnam
October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
2013,
Hanoi,
Vietnamthethe markers
markers areare appeared
appeared as
as whitewhite circles
circles inin thethe CT
CT images.
images. The
The CT
CT images
images at
at thetheinitialinitial condition
condition show
show thatthat all
all thethe markers
markers were
were placed
placed properly.
properly. In
In thethe CT
CT images
imagesobtained
obtained after
after three
three loading
loading steps,
steps, it
it isis realized
realized thatthat thethe markers
markers were
were spatially
spatially
moved
up
from
22
mm
depth.
The
relative
dark
color
in
these
CT
imagesmoved up from 22 mm depth. The relative dark color in these CT images isisconsidered
considered asas thethe low
low density
density area
area oror thethe failure
failure zone
zone ofof thethe soil
soil duedue toto laterallateralloadingloading (Pham(Pham etet al.
al. 2004).
2004). It
It is
is interesting
interesting toto observe
observe thatthat thethe areas
areas ofof movements
movementsof thethe soil.
soil. AtAt thethe depths
depths of
of 46
46 mm
mm
of
of thethe marker
marker were
were inside
inside thethe failure
failure region
region of
and
70
mm,
it
is
seen
that
the
markerswere
moved
horizontally
in
the
area
of
relaand 70 mm, it is seen that the markers were moved horizontally in the area of relative dark
dark color.
color. Thus
Thus itit isis considered
considered here
here thatthat thethe movements
movements ofof thethe markers
markers
tive
reflectthebehaviorofsoil
insidethefailurezone.
reflect the behavior of soil inside the failure zone.

17mm
17mm

18mm
18mm

19mm
19mm

Pile
Piledepth
depth

20mm
20mm

21mm
21mm

22mm
22mm

46mm
46mm

70mm
70mm

Initial
Initiald = 5 mmd = 5 mmd = 10 mm
d = 10 mm

d = 15 mm
d = 15 mm

FigureFigure 7.
7. CT
CT images
images at
at 88 depths
depths under
under groundground surface
surface ofof initial
initial condition
condition and
and
after
three
loading
steps
d
=
5
mm,
d
=
10
mm,
and
d
=
after three loading steps d = 5 mm, d = 10 mm, and d = 1515 mm.
mm.

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5.2 Visualization of 3-D behavior of the soil due to lateral pile loading
1) Technique of image processing analysis for simulating 3-D behavior of the soil:(a) Depths of all the markers under the ground surface after their
movements in each loading step are calculated from the CT images;(b) Spheres with the same diameter of the markers (i.e. 2 mm) are drawn
at positions of cross sections of the markers in the CT images (i.e. white circles).
It is noted that the spheres are drawn in the way that their centers are coincidedwith the centers of the markers’ cross sections. At this step, the depths of all thespheres are assigned as 0 mm;(c) Depths of all the spheres under the ground surface then are changed
according to those calculated in step (a); and(d) Images of the 3-D movements of the markers or 3-D behavior of thesoil are visualized.
2) Calculation of depths of the markers:
Figure 8 shows a large scale image of a marker, which is cut by an x-ray
beam. It is noted in this figure that: (1) the thickness of this x-ray beam was 1 mm,
and (2) cross section of a marker in the CT image is always appeared as a circle atthe middle plane of the cutting x-ray beam.
The radius, R, of a marker is 2 mm. That of cross section of a marker in a
CT image is measured to be r. Thus the distance, h, from the center of that marker
to its cross section in the middle plane of the cutting x-ray beam is calculated as:h=R2 − r2(1)

Therefore, the distance from the center of the marker to the ground surface,
Hm, is calculated as:
Hm = H ± h(2)

where H is the distance from the middle plane to the ground surface. It is noted in
Equation (2) that the depth, H, of the middle plane of a certain x-ray beam under
the ground surface at the soil box is always availably known from the loading test.
Ground surface

Cross section of marker
CT slice

H

Hm

1mm

h

r
R

MarkerCenter ofmarkerMiddle plane

Figure 8. Large scale of a marker and an x-ray beam.
A techniqueof imageanalysis
processing
analysis recommended
research of laterally loaded
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recommended
for research forof laterally
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using
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October
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It is determined based on the setting on the CT scanner before carrying out
process of scanning. The positive or negative sign in Equation (2) is taken
depending on position of the middle plane, which is considered to be above orunder the center of the marker.
3) Observation of 3-D behavior of the soil:
Figure 9 shows a 3-D simulating image of the markers at three depths in
the initial condition and after three loading steps, including deformations of themodel pile. It is realized that the markers at 22 mm depth were almost moved up
totally. The markers near the model pile were moved obliquely from the initial
positions. This can be explained as a slip up of the soil due to lateral pile loading.
For the markers gradually far from the model pile, their movement tendencies
were on upward direction. It may be due to the pressure of the lateral load at areas
far from the pile could not exceed the natural soil pressure (at rest). It is seen thatthe markers lying on X-direction at the center line were mostly affected from thepressure of the lateral load. It is also observed in these figures the spatial
increments of movements of the markers.
For the markers at 46 mm depth, they moved horizontally instead of
upward after the first and second loading levels. These may be because thepressure of the weight of the upper soil of this level was relatively large comparedto that of the lateral load. But after the third loading step, the markers were movedup.
For the markers at 70 mm depth, they were not moved after the firstloading step because the pressure of the weight of the upper soil was relatively
larger. After the second and third loading levels, they were only moved
horizontally.
By connecting centers of the markers at the stages before and after loading,
vectors of their movements or 3-D behavior of the soil inside the failure zone dueto the lateral pile loading are indicated in Figure 10.
Z

Lateral load
Y

Soil box
X

Level 122mm depth
Model pile

Level 246mm depth

Level 370mm depth

Figure 9. 3-D simulation of markers and model pile after three loading steps.

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Z
Y
X

Model pile

Level 1

Level 2

Level 3Figure 10. Vectors of movements of markers at three levels in soil box after
three loading steps.
Selected
markers

Cross sectionof model pile

Center line

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

16
17
18
19
20
21
22
23
24
25
26
27
28
29
30

31
32
32
34
35
36
37
38
39
40
41
42
43
44
45

46
47
48
49
50
51
52
53
54
55
56
57
58
59
60

61
62
63
64
65
66
67
68
69
70
71
72
73
74
75

76 91 106 121
77 92 107 122
78 93 108 123
79 94 109 124
80 95 110 125
81 96 111 126
82 97 112 127
83 98 113 128
84 99 114 129
85 100 115 130
86 101 116 131
87 102 117 132
88 103 118 133
89 104 119 134
90 105 120 135

Figure 11. Plan view of numbered markers.
5.3 Quantitative discussion
Based on the vectors of the movement of the markers, quantitativeevaluation on tendencies of the 3-D behavior of the soil could be conducted. Inorder to show that possibility, several typical markers at 22 mm depth wereselected.
Figure 11 shows a plan view of numbered markers at 22 mm depth withthe selected ones, which are those of numbers 8, 68 and 128 on the center line.
Figure 12 shows a quantitative evaluation on tendencies of 3-D movements ofthese markers after three loading steps. It is noted in this figure that three vectorsof the movement are drawn in their local coordinate systems of O8X8Y8Z8,

A techniqueof imageanalysis
processing
analysis recommended
research of laterally loaded
A technique ofimage processing
recommended
for research forof laterally
pile
using
a
systemof
X-rayCT
scannerloaded pile using a system of X-ray CT scanner765

October
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Hanoi,Hanoi,
Vietnam0ctober
Vietnam

O68X68Y68Z68 and O128X128Y128Z128, which are congruent to the main coordinate
Note:
system, OXYZ, shown in Figure 10.
Z8

Z128

Loading steps 3

Y8

5.78

Loading steps 2

Z68

Y68

3.78

Loading steps 1

5.14

0.62

Y128

0.46
0.2

1.8
3.32

O8

2.8

5.46

7.84

X8

Z128

1.72

O68

1.4 2.42

Y128

O128

0.13
0.1

X128

0.14

3.18

X68

O128

X128

Figure 12. Tendencies of movement of markers number 8, 68 and 128.
.
In Figure 12, it is shown that when the loading is increased, the tendenciesof the movement of these markers are those on upward direction. It is also
realized from this figure that the marker number 8 is moved obliquely in the
X8O8Z8 plane when the loading is increased, but the tendency of movement of thismarker becomes upward at large loading level.
Based on these typical results, it is shown that the technique developed
herein for image processing analysis could be used for precise evaluation of soil
behaviors inside the failure zone due to lateral pile loading.

6. CONCLUSIONS
A technique of image processing analysis for precise visualization of 3-D
behavior of soil inside the failure zone due to lateral pile loading was developed.
The results showed a possibility of this technique that could be applied forquantitative evaluation of soil behavior not only for laterally loaded pile but also
for other field of study in geotechnical engineering, in order to improve safety forbuildings’ pile foundation of mega cities in Asia.

REFERENCES
Broms, B. B. 1964. Lateral resistance of piles in cohesionless soils, Proc. ASCE
90, SM (3): 27-63.
Otani, J., Mukunoki, T. and Obara, Y. 2000. Application of X-ray CT method forcharacterization of failure in soils, Soils and Foundations, 40(2): 111-118.
Pham, K. D., Sano, J. and Otani, J. 2004. Development of new test apparatus forlateral pile loading using X-ray CT scanner, Proc. Vietnam - Japan Joint Seminaron Geotechnics and Geoenvironment Engineering: 86-93.
Reese, L. C., Cox, W. R. & Koop, F. D. 1974. Analysis of lat-erally loaded pile insand, Proc. Offshore Technology Con-ference, Houston, TX: OTC2080.

766

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Assessment of urbanization impact totemperature, rainfall and flooding situationof Ha Noi city taken into accountclimate change
Vu Minh Cat,
Water Resources University,
Ha Noi, Viet Nam
ABSTRACT
Rain induced inundation is still serious in old city of Ha Noi although thedrainage system has been being improved and upgraded gradually.
Rainfall data from 1960 till now show that annual rainfall trends to decrease 3 to
5%, but daily rainfall and shorter duration is increased about 10%. The
urbanization is being occurred rapidly from city centre to outside that causes
reducing some thousands hectares of agricultural land and lake and pond area isalso decreased from 850 hectares to 550 hectares from 1990 till now. The main
drainage rivers including To Lich, Lu, Set, Kim Nguu and some hundreds ofcanals, gutters from core city have been improved and canalized. However due tomany reasons such as unacceptable dimension of drainage sluices, small crosssection of drainage canals, sparse network of drainage, blocking up due torubbish and waste materials etc. the inundated situation is occurred frequently,
even rainfall seems to reduce.
Keywords: Climate change, Rainfall regime, core area of Ha Noi, rain induced
inundation, regulated lake
1. INTRODUCTION
In 1954, area of Ha Noi is of 152km2 and population of 53.000 inhabitants; in1961 it was increased to 584km2 in area and 91.000 peoples; in 1978, Vietnameseparliament decided to expand the capital into 2.136km2 and 2.5 millions of
inhabitants; in 1991, Ha Noi capital area was still of 924km2 and more than 2
millions of people and in 2009, Hanoi was expanded with 3.325 km2 and morethan 6.4 millions inhabitants and becomes 17th ranking of world capitals in term of
area.
Together with expansion of area, the urbanization in Ha Noi is occurred rapidly
with many new living quarters, industrial areas and infrastructures and huge areaof agricultural land is transformed into city. It means that ground surface isbetonized and lake and rain water stored land is reduced significantly.
Natural rivers that can regulate water for the core area of Ha Noi are Nhue in thewest and To Lich, Lu, Set and Kim Nguu. Now they are main drainage system
and waste water for core area. However, the conveyance capacity is reduced
significantly due to sedimentation and blocked seriously socio-economic activities.

767

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamLake and pond area is also decreased from 850 hectares to 550 hectares from 1990
till now that is one of the reason to decrease rain regulated capacity and increased
inundation.
With rapid urbanization, the meteo-hydrological parameters as temperature,
rainfall are also changed quickly with higher rainfall intensity in rainy season, but
drought also becomes more serious. With above reasons, inundated situation
becomes seriously for core area of Ha Noi.
In this paper, the change of rainfall pattern and inundated situation is assessed andsimulated for the core area of Ha Noi under the impact of urbanization andpropose solutions to mitigate negative effects and gradually to improve city
environment taken into climate change.
2. RESEARCH METHODOLOGY
In order to assess the inundated situation in core area of Ha Noi, the following
methods are applied:
1. Based on observed data of meteo-hydrology, topography, inundated location,
depth and duration and drainage system, the analysis and computation is carriedout to assess and find out the inundated reasons for the core area of Ha Noi.
2. Application of Storm Water Management Model (SWMM) to simulate andquantitative assess inundated situation at core area with 2 rainfall events in
November 1984 and November 2008. From simulated results, solutions to
mitigate negative situation are proposed.
3. RESEARCH RESULTS AND DISCUSSION
3.1 Brief information of topography and existing drainage system of corearea
As said above the study is carried out for the old Ha Noi city including 9 districts
namely Ba Đinh, Hoan Kiem, Đong Đa,
Tay Ho, Hai Ba Trung, Thanh Xuan, CầuGiay, Hoang Mai and Tu Liem. Averageground elevation of area is of + 7 t0 + 8m,
in which area having elevation greater than
+8.00 is of 3,5 km2 distributed mostly at
Hoan Kiem district (narrow strip runningfrom Yen Phu to river port of Ha Noi) andpart of Ba Ding, Cau Giay districts along
Hoang Hoa Tham, Buoi and dike from Tay
Ho to Dong Mac. Elevation from +5 to +8
is of 50% and distributed mostly in southand southwest including low lying lands for
agriculture, aquaculture and housing areas
Lakes, ponds and natural rivers are locatedat the end of catchment with elevation
lower than +5.00 in Dong Da, Thanh Xuan,
Hai Ba Trung and Thanh tri districts.
Figure 1: Study area

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To lich, Lu, Set and Kim Nguu are main drainage system for the core area. It isshown in figure 1.
Waste and rain water from housing areas and streets is concentrated firstly into
under ground sluices and then flowing to gutter and minor drainage canal justafter the sluice lines and finally running to main 4 drainage rivers where watercontinues to flow the south. In case water level at downstream of Thinh Lietbarrage is lower than +3.5m, it is opened and water is released into Nhue river andif water level there is greater than +3.5m, barrage is closed and water is flowing to
Yen So lake through the canal of 7 km and pumped to Red river.
3.2 Development of infrastructures in surrounding core area
In current years, the infrastructures in Ha Noi are developed significantly tocontribute socio– economic activities and serve citizen needs. Many transportroads are improved and constructed such as Hung Vuong avenue, national road 32,
highway Phap Van – Cau Gie, ring road 3 Mai Dich – Phap Van etc. and many
new urban areas are developed and expanded into west and southwest areas suchas Linh Dam, Đai Kim, Dinh Cong, Tran Duy Hung, My Dinh Sport composite
etc. However, existing drainage system is exposed many disadvantages and did
not meet requirement if being considered in term of water drainage. When lowlying areas that are agricultural land or lakes are reduced then water body to store
water temporarily before flowing to drainage system is also not existed that willcause more inundation in the core areas. In the other hand, the drainage system in
the new developed sub-areas are not meet the requirement, so many new
developed areas are also inundated in case of rainfall event is only less than 100
mm.
3.3 Rainfall regime changes due to climate change
In general, inundation in Ha Noi is mostly due to rainfall occurring in shortduration (from hour to two days). Based on the recording data at Lang, Ha Noi
from 1961 to 2010, the time series of daily and annual rainfall are constructed,
then it shows that daily rainfall seems increasingly when annual rainfall isdecreased. The increase of daily rainfall will impact strongly to drainage system
and inundated situation will be more serious if drainage system is not improved
accordingly.
Maximum Daily rainfall at Lang - Ha Noi (1961 - 2010)

Yearly Rainfall at Lang - Ha Noi (1961 - 2010)

400.0

2800.0350.0

2600.02400.02200.0250.0

Rainfall (mm)Daily Rainfall (mm)

300.0

200.0

2000.01800.0150.0

1600.0100.0

1400.050.0
19601200.0

1965

1970

1975

1980

1985

1990

Year
X1max

1995

2000

2005

2010

1000.0
1960

1965

1970

1975

1980

1985

1990

1995

2000

2005

2010

Year

Linear (X1max)

X(mm)Linear (X(mm))

Figure 2: Time series of daily and annual rainfall at Lang, Ha Noi

of impact
urbanization
impact to temperature,
rainfall andflooding situation of Ha
Asessment ofAssessment
urbanization
to temperature,
rainfall and flooding
situation
Noi
city
taken
into
account
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Vietnam

Two typical rainfall events in November 1984 and November 2008 are considered
for simulation of hydraulic regime and inundation in core areas.
Table 1: Hourly rainfall of 2 considered rainfall events
Time
XI/1984 XI/2008
0-1
0.0
2.5
1-2
0.0
11.7
2-3
0.3
24.3
3-4
0.1
28.4
4-5
1.2
39.1
5-6
0.5
6.8
6-7
2.1
40.6
7-8
5.1
5.5
8-9
5.7
17.1
9-10
5.0
68.8
10-11
5.7
24.4
11-12
4.8
6.6
12-13
34.4
0.3
13-14
8.4
0.1
14-15
6.0
16.8
15-16
11.2
17.8
16-17
22.3
4.8
17-18
27.0
15.2
18-19
3.2
10.5
19-20
1.6
13.2
20-21
4.7
5.5
21-22
5.5
19.2
22-23
13.0
3.0
23-24
94.9
2.7

Time
XI/1984 XI/2008
0-1
5.9
16.9
1-2
0.6
126.5
2-3
52.1
0.4
3-4
12.1
0.1
4-5
18.6
1.8
5-6
60.5
2.9
6-7
16.7
6.1
7-8
1.9
20.5
8-9
2.2
2.7
9-10
1.1
3.0
10-11
0.3
3.7
11-12
0.0
13.1
12-13
0.0
2.2
13-14
0.0
5.8
14-15
0.0
1.6
15-16
0.0
0.1
16-17
0.0
0.0
17-18
0.0
0.0
18-19
0.0
2.2
19-20
0.0
0.2
20-21
0.0
0.0
21-22
0.0
0.0
22-23
0.0
3.0
23-24
0.0
3.6
560.4
475.2

3.4. Simulation of hydraulic regime and inundated situation in core areas
In order to assess the hydraulic regime and inundation situation, SWMM is used.
The study area is schematized in model as figure 3 in which there are 60 sub-areas,
19 lakes, 104 nodes, 120 sluice lines, 12 barrages, 4 drainage river name To Lich,Lu, Set, Kim Nguu and drainage pumping station of Yen So.

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Figure 3: Schematization of drainage system in core area of Ha Noi
Logically the above drainage system will be worked as following when rainfall
happens:- Rain water at housing and sub-areas (being shown as yellow colour) willconcentrate into sluice lines, later it flows to gutters and small canals connected
directly to the sluice lines and finally flowing to main drainage rivers.
- 4 drainage rivers namely To Lich, Lu, Set and Kim Nguu are open channel tocarry rain water from catchment to the end of system where water will release toNhue river if water level downstream of Thanh Liet barrage is less than +3.50m.
In case water level downstream of Thanh Liet is greater than +3.50m, rain water
will flow through the canal to Yen So reservoir and finally pumped to Red river.
- It is also mentioned that in the system, there are 19 retention lakes that can store
a part of rain water in it and will be released gradually when water level indrainage river is lowered.
- Yen So pumping station is included 5 normal pumps and 18 emergency pumps
with total capacity of 90 m3/s. When water level at suction tank is greater than
+1.50m, the normal pump will start working and if water level is higher than
+2.40m, pumping station will be connected to Yen So reservoir where rain waterof impact
urbanization
impact to temperature,
rainfall andflooding situation of Ha
Asessment ofAssessment
urbanization
to temperature,
rainfall and flooding
situation
Noi
city
taken
into
account
climatechangeof Ha Noi city taken into account climate change771

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamwill be concentrated there and emergency pumps start working. How many pumps
are operated depending on quantity of rain water coming to reservoir. The wholesystem will be stopped when water level in suction tank is lower than +1.50m.
Regulated procedure of pumping station is shown in figure 4.

Figure 4: Working procedure of pumping station
Two rainfall events are used for simulation is shown in table 1.
In order to see the change of water level and inundated situation of the core areas,
number locations in the scheme are extracted.
- Node 22 belongs to To Lich river in upper part of Thanh Liet barrage- Node 49 is on Lu river around crossing point of Lu river and Truong Chinh
street- Node 62 is on Set river around crossing point between Set river and Nga Tu
Vong street- Node 68 belongs to Kim Nguu river at the section between Tran Khat Chanand Lac Trung streets- Node 72 belongs to Kim Nguu around Mai Dong bridge area
- And Thu Le and Linh Dam lakes
Simulated results are summarized in table 2 and shown in the figure 5.

T
T

No
de

01
02
03
04

22
49
62
68

05
06

772

Table 2: Simulated results at nodes on the drainage system
Duration (hrs) WL >River/lak
Peak water level (m)+3.7e
XI/1984
X/2008
XI/1984
X/2008
To Lich
42
70
5.00
4.80
Lu
42
70
5.40
5.40
Set
50
81
5.25
5.25
Kim
45
75
6.00
5.50
Ngu
Thu Le
45
70
5.15
6.00
lake
Linh
40
70
5.25
5.00
Dam

GL
(m)
5.92
5.56
5.95
5.95
7.80
5.60

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Water Level at node 22, To Lich

Water level at node 49 LU river
W ater level (m )W ater level (m )

5.00
4.50
4.00
3.50
3.00
0

20

40

60

80

100

120

5.50
5.00
4.50
4.00
3.50
3.00

0

140

10 20 30 40 50 60 70 80 90 100 110
Time (hours)

Time (hours)
Year 2008

Year 1984

Year 1984

Water level at node 68 Kim Nguu river
6.00

5.50
5.00
4.50
4.00
3.50
3.00
0

10

20

30

40

50

60

70

80

90

100

Water level (m)W ater level (m )Water Level at node 62 SET river
5.50
5.00
4.50
4.00
3.50
3.00
0

Time (hours)
Year 2008

Year 1984

5.00
4.00
3.00

0 10 20 30 40 50 60 70 80 90 100 110 120
Time (hours)
Year 1984

Year 2008

20

30

40

Year 1984

50

60

70

80

90

100

110

Year 2008

Water level at Linh Dam lake
Water level (m )

6.00

10

Time (hours)

Water level at THU LE lake
W ater level (m )Year 2008

6.00
5.00
4.00
3.00

0 10 20 30 40 50 60 70 80 90 100 110 120
Time (hours)
Year 1984

Year 2008

Figure 5: Simulated results at nodes in the drainage scheme
3.5. Discussion- Rainfall patterns both quantity and distribution shape in November 1984 is more
unfavorable than that in November 2008 in term of drainage. As recorded,maximum hourly rainfall in 1984 is of 126.5mm, when it was of 68.8mm in 2008.
Similarly total rainfall in 3 continuous hours between 2 above events is of
190.7mm/110.4mm and 560.4/475.2mm for two days. But inundation in 1984 waslesser than that in 2008 in term of area, depth and duration- Highest water level: As results summarized in table 2, maximum water level at
nodes 22, 49, 62 and 68 seems to change litter bit at each point for both rain
events. It means that although rainfall in 1984 is bigger, but the role of water
regulation of lake, low-lying land around the city and large unconcretization ofland in the city can reduce the inundation.
- Duration to keep high water level in drainage rivers (H > 3.70m): It is a great
difference between 2 rainfall events. With rainfall event of 1984 the duration is
only 42 to 50 hours, but it is of 70 to 80 hours for rain event of 2008. The sameof impact
urbanization
impact to temperature,
rainfall andflooding situation of Ha
Asessment ofAssessment
urbanization
to temperature,
rainfall and flooding
situation
Noi
city
taken
into
account
climatechangeof Ha Noi city taken into account climate change773

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamsituation occurred at 2 studied lakes of Thu Le and Linh Dam. It can be explainedthat drainage rivers are good enough to convey water, but rain water is blocked at
upper stages (gutters, small canals and sluice lines) to cause more inundation in
the city and the longer time of releasing water to the main drainage rivers.
- As said above, ground elevation (GL) is decreased in the direction NW – SE andalmost higher than maximum water level along the drainage rivers. But based ondata reported by The Ha Noi drainage Company Ltd., with the rainfall event ofaround 100 mm then there are more 20 inundated locations permanently in which
the inundated depth of 0.4 – 0.5m was existed at Le Duan, Pham Hung, Thai Ha,
Thai Thinh, Quan Nhan, Nguyen Xien streets
From simulated results and observed data of Ha Noi Drainage Company Ltd.,
one can have conclusions as following:- After rehabilitation, upgradation and new construction, 4 main drainage rivers
and Yen So pumping station are good enough and they can drain perfectly withthe rain event up to 310 mm in 2days if the drainage system is operated correctly.
- The serious inundation along the streets in core area can be explained asfollowing:1) The large reduction of retention lakes in the city
As stastical data of Ha Noi constructive Department, there are 111 lakes with total
area of 1,165 hectares in which West lake is of 500 hectares (about 50%). In
more than 20 year up to now starting in 1990, there are 21 lakes were disappearedwith more than 300 hectares (or 36%). If seeing into existing lakes, one can findthat due to unmanageable status water surface is encroached and reduced
significantly in term of area and lake bottom is deposited as waste material fromsocio-economic activities and resulting that stored capacity of these lakes aregradually smaller. For this reason, the retention role of lake is disappeared andwater is overflowed on the ground surface where are concretized mostly andinundated situation becomes more serious.
2) Narrowing agricultural land around the city due to urbanization
In 15 current years, some thousands hectares of agricultural and low-lying lands
that can store much rain water is transformed into urban ones. Many new housing,industrial areas are constructed and transportation infrastructures are expanded in
the west and south of core zone belonging Tu Liem, Dong Da, Thanh Xuan,
Hoang Mai, Hai Ba Trung districts. It is one of the reasons to accelerate inundated
situation in the city. If considering the drainage system in the new urban areas
itself, we can say that it is behind the requirement.
3) On sluice network collecting directly rain water from house roofs andstreets
Ha Noi is more flat and rain to cause inundation is more serious, but sluice
network to collect directly rain water from house roofs and streets is not met
requirement. It means that network is not dense enough and dimension of thesluice seem too small while they are deteriorated and blocked by raw rubbish, so
rain water could not be transported through the sluice lines and it must be kept in
the street to cause inundation.
4) On the minor canal system connected directly to sluice network
Logically rain water firstly is collected from the roofs and streets and transported
through sluice network and latter water will transport to the minor canal system
connected directly to sluice network before going to the main drainage rivers. The
length of this minor system is of some hundred kilometers, located nearby the774

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ICUS Report 73

housing and subjected to all socio-economic activities. They are occupied illegallyand cross section is narrowed many sections. Also all waster materials andrubbish are put in it, so water conveyable capacity through it is reduced
significantly. At present, many minor canals are concretized and become close
system, but with uncontrollable status, they may become dead in near future anddrainage system of Ha Noi become worse.
CONCLUSIONS AND RECOMMENDATIONS- Based on observed data, reports of rehabilitated, upgraded and new constructed
projects of drainage network in Ha Noi and simulated technique, we canunderstand more clearly on drainage network and inundated situation in core zoneof Ha Noi.
It is clearly that the main reasons to cause seriously inundation is- To narrow the retention lakes due to illegal land occupation and put into it muchwaste materials and rubbish- To transfer much low-lying and agricultural lands around core zone into urban
ones- The sluice and minor canal network is destroyed and deteriorated seriously due
to uncontrollable activities, so they could not convey rain water to the main
drainage rivers.
- Study realized that 4 main drainage rivers and Yen So pumping station are goodenough to drain rain water with rain event of more than 310mm in 2 days.
However, under the impact of climate change, rainfall in short period will be
increasing, so it is needed to forecast these changes for the adaptation of drainage
system in future.
- Study results are ideas for master plan of drainage system in particular and fordesign of whole infrastructures including electrical cables, water supply and evenunderground transportation system that will be developed in future.
REFERENCES(1) Hoang Van Hue (2002). The drainage, Scientific and Technical Publishing
House, Ha Noi.
(2) Lewis A. R. (2008). Storm Water Management Model, User’s Manual,
Version 5.0. EPA.
(3) TCVN 7957:2008. The drainage – Network outside structures – Design
standards.
(4) The number of drainage and waste water treatment projects for Ha Noi from2002 till now.

of impact
urbanization
impact to temperature,
rainfall andflooding situation of Ha
Asessment ofAssessment
urbanization
to temperature,
rainfall and flooding
situation
Noi
city
taken
into
account
climatechangeof Ha Noi city taken into account climate change775

October 2013, Hanoi, Vietnam

776

New Technologies for Urban Safety of Mega Cities in Asia

Study on carbonation and pore structureof cementitous materials
exposed to supercritical CO2
Ryosuke HIRAI1, Hikaru ISOZAKI2, Shingo ASAMOTO3
1
Graduate Student, Department of Civil & Environmental Engineering,
Saitama University, Japans12me119@mail.saitama-u.ac.jp
2
Undergraduate Student, Department of Civil & Environmental Engineering,
Saitama University, Japan
3
Associate Professor, Department of Civil & Environmental Engineering,
Saitama University, Japan

ABSTRACTIn this study, the carbonation progress of the cement paste in an injection well fora carbon capture and storage project is investigated. The hardened cement paste
is exposed to supercritical CO2 to examine the progress of the carbonation andthe variation of the pore structure under the severe condition. The application of
the cements such as Ordinary Portland and fly ash cement in civil engineering
field to the well is also studied as well as the application of oil well cement in oil& gas field. In the case of oil well cement, when it is subjected to hightemperature and high pressure, small amount of C3A could prevent from cracking.
On the other hand, many cracks on the surface of cement paste using Ordinary
Portland cement occur and cement paste with fly ash has micro cracks on thesurface under the severe condition. When oil well cement is used, the carbonationof C-S-H gel causes the increase of CaCO3 amount in the paste, while Ordinary
Portland cement and fly ash cement slightly increase the amount of CaCO3 due tothe C-S-H gel carbonation. It is inferred that C-S-H gel characteristics of oil wellcement could be different from the others and lead to different precipitation of
CaCO3. It is experimentally found that the carbonation of C-S-H gel makes thepore structure coarse, especially pores of over 100 nm diameter in all cements. It
is indicated that oil well cement is appropriate for the deeper well with higher
temperature and pressure. Since the resistance of the carbonation under
supercritical CO2 is not significantly different among the cements. Cements otherthan oil well cement might be applied to the shallow injection well.
Keywords: CO2 capture and storage, carbonation, pore structure, supercritical
CO2, oil well cement
1. INTRODUCTION
The reduction of the CO2 emission is one of the most significant issues. As thecountermeasure to the reduction, Carbon dioxide Capture and Storage (CCS)777

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamprojects have been focused on as one of state-of-art technologies in recent years.
In the projects, the CO2 collected from factories is injected into a geologicalreservoir at deep underground through the well and stored in the reservoir for along time in order to isolate the CO2 to be reacted with the mineral as shown in
Figure 1. The well is composed of a cement paste and a steel casing, and reaches
over 1000 m depth. The well could have various deteriorations under the severe
environment of deep underground such as high pressure, high temperature andhigh concentration of the injected CO2. When the well is seriously deteriorated,
the leakage of the CO2 gas is likely to occur through the deteriorated sections.
Figure 2 shows that the possible pathways of the CO2 gas leakage, e.g. cracks inthe deteriorated casting and cement paste, the interfaces between thecasing/cement and cement/formation. The prevention of the leakage of the CO2

Figure 1: The overview of CCS projects

Figure 2: The cross section of the welland pathway of the CO2 gas

Figure 3: Phase change of the CO2778

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gas stored in the reservoir is indispensable for CCS projects. The injected CO2
could be changed into a supercritical state at deep underground (Figure 3) due tohigh temperature and pressure. Supercritical CO2 is intermediate fluid withcharacteristics of both gas and liquid, and has high permeability. When the well is
exposed to the supercritical CO2, it is suggested that the deteriorations could befaster 1) in comparison with the case of CO2 gas or liquid However, thecarbonation process of cement paste under supercritical CO2 has not yet beenclarified. For development of the technology, the integrity of the well should beinconsistently comprehended for the effective confinement of the CO2 in thegeology.
In this study, the authors focus on the hardened cement paste in the well andstudy the carbonation process under supercritical CO2. In the experiment, cement
pastes with oil well cement, Ordinary Portland cement and fly ash cement are
exposed to the supercritical CO2 under the severe condition assuming the actual
environment at the deep underground. The applicability of each cement to the
CCS well is examined. After the exposure, the phenolphthalein is transfused on
the cutting surface and thermal analysis test are carried out in order to measure thecarbonation depth. Mercury intrusion porosimetry test is also conducted tomeasure the change in the pore structure due to the carbonation.

2. EXPERIMENTAL PROGRAM
2.1 Materials
Three types of the cement were used in the experiment: oil well cement (OWC),
Ordinary Portland cement (OPC) and the Ordinary Portland cement with 20 %replacement by fly ash (FA). Although the cement paste in the well generally has
a water/binder ratio (W/B) of about 45 %, the W/B of the cement paste in theexperiment was set to 55 % in order to promote the carbonation during a limited
experimental period.
2.2 Experimental set-up
2.2.1 Supercritical CO2 exposure
The specimen size of the cement paste was 100 mm x 50 mm cylinders.
Specimens were cured under sealing until age of 7 days at 80 . The curing
temperature was determined assuming the environment of the underground at a
depth of about 2000 m according to the temperature rise of 3 /100 m withincrease of the depth. After the curing, the upper and lower parts of about 25 mm
in the specimens were cut (Figure 5) by the concrete cutter in order to prevent theeffect of the bleeding. The cutting specimens were exposed to supercritical CO2 inthe vessel of supercritical CO2 generator as given in Figure 4. Supercritical CO2
was generated by setting the condition in the vessel to 80 at pressure of 10 MPa.
The exposure periods were 1 day, 3 days and 7 days. Two specimens wereprepared for each condition, thus, total 18 specimens were used.

Study on carbonation and pore structure of cementitous materials exposed toStudy on carbonation
and COpore
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2 structure of cementitous materials exposed to supercritical CO2779

October
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Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 4: Supercritical CO2 generator and vessel

Figure 5: Cutting method of the specimens
2.2.2 Phenolphthalein indicator test and Thermal analysis test
After the exposure to supercritical CO2, the solution of phenolphthalein was used
to measure the carbonation depth of the specimen. The specimens after the
exposure were cut vertically, and the 1 % phenolphthalein solution was splayedon the cross section to measure the noncolored depth due to the carbonation asshown in Figure 5. Also, thermal analysis test was conducted to measure thevariation of hydration products due to the carbonation. The carbonation reactionin the cement paste is shown in equation 1.
Ca (OH ) 2 + CO2 → CaCO3 + H 2 O(1)The same specimen as used in the phenolphthalein indicator test was used inthermal analysis test. The samples for the test were collected at the three points(0-5 mm, 10-15 mm, 20-25 mm) from the surface of the specimen exposed tosupercritical CO2 as shown in Figure 6. The collected samples were grinded into
powder and set in TG-DTA thermal analysis test machine. The temperature wasrisen from room temperature to 100with 10 /min, and remained for 10
minutes to evaporate the liquid water in the sample as shown in Figure 7. Then,the temperature was risen to 1000 with the same temperature rise velocity. The
amount of Ca(OH)2 and CaCO3 due to the dehydrogenation and decarbonized780

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Figure 6: Sampling points

Figure 7: Result of DTA analysis

reaction were obtained by the mass loss based on the DTA information. Figure 7
and CaCO3 wasrepresents that Ca(OH)2 is dehydrated at 400-500
decarbonized at 700-800 according to the endoergic peak by the DTA.
2.2.3 Mercury intrusion porosimetry test
The mercury intrusion porosimetry test was carried out in order to examine thechange in the pore structure due to the carbonation under supercritical CO2. After
exposing for 1 day and 7 days, the samples were collected from the two points at
5 mm square area (0-5 mm, 20-25 mm from the exposure surface) in the same
specimen as that for the thermal analysis test. The measurement was conducted
after the vacuum freeze-drying for 24 hours. The pore distribution in the range
from 3 nm diameter to 360 μm diameter was obtained assuming the cylindricalmodel which has 0.484 N/m of surface tension of the mercury and 130 degrees ofcontact angles.

3. EXPERIMENTAL RESULTS
3.1 Carbonation phenomena in supercritical CO2 exposure test
3.1.1 Phenolphthalein indicator test
The experimental results of the phenolphthalein indicator test are shown in Figure
8. It was experimentally found that the red colorings by the phenolphthaleinsolution were heterogeneous in all cases, so that it was difficult to identify the
carbonation depth. Especially, in the case of the OPC, micro cracks anddestruction were observed in all specimens after the exposure, and the carbonation
progress was irregularity. It is inferred that rapid drying under high temperatureand high pressure could cause the cracking. In addition, C3A included in Ordinary
Portland cement could react rapidly during the curing and the exposure test at
high temperature and results in the coarse pore structure2), 3) and the strength could
decrease. On the other hand, the cracks were not observed in the case of the OWC.
It is because a few C3A and rich C3S included in oil well cement could
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and COpore
supercritical
2 structure of cementitous materials exposed to supercritical CO2781

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 8: Result of the phenolphthalein indicator test after thesupercritical CO2 exposure test

Figure 9: The amount of CaCO3
as exposure days at the 0-5 mm from the exposure surface
continuously develop the strength even under high temperature, so that the cracks
were not observed visually. In the case of the FA, the pozzolanic reaction could beaccelerated during the curing at high temperature and the strength was developed
not to cause the observable cracks but micro cracks on the surface.
3.1.2 Thermal analysis test
The variation of the CaCO3 content at the 0-5 mm from the exposure surface isshown in Figure 9. The CaCO3 content 7 days after the exposure is increased in

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Table 1: The amount of Ca(OH)2 of the specimens cured with sealing under theroom temperature for 26 days

Figure 10: The amount of CaCO3 as
the depth from the surface at the 7 dayof the exposure

Figure 11: The amount of CaCO3 as
the exposure days of the OWC

comparison with that 1 day after the exposure in all specimens. The CaCO3
content in the OWC and OPC was almost the same and that of the FA was thesmallest. The reason why the CaCO3 content of the FA was the smallest is that
Ca(OH)2 could be used due to the pozzolanic reaction with the fly ash during thecuring at high temperature and an initial amount of Ca(OH)2 could decrease. Table
1 shows the amount of Ca(OH)2 of each specimens cured under sealing at theroom temperature for 26 days. Although it was different curing condition with theexperiment, the amount of Ca(OH)2 in the FA is less than the half of that incomparison with the OWC and OPC and the above hypothesis could be valid.
According to the result of phenolphthalein indicator test, as shown in Figure 8,
the part of 0-5 mm (surface) were not colored in all specimens on 1 day after
exposure. It is suggested that Ca(OH)2 near the exposed surface could becarbonated. All Ca(OH)2 at the surface are carbonated at 1 day after exposure asshown in Figure 11 but the amount of CaCO3 still increase after that. When all
Ca(OH)2 are carbonated, it is anticipated that the main hydration products, C-S-H
gel, is carbonated after the carbonation of all Ca(OH)2 4) under severe conditions
such as supercritical CO2. The increase of CaCO3 content at the surface after the 1
day of the exposure could be caused solely by the carbonation of C-S-H gel.
However, the increase of CaCO3 in the OWC was larger than those in the OPC
and FA. It is speculated that the C-S-H gel in the cement paste of the OWC could
be carbonated rapidly or the amount of the component in C-S-H gel which could
generates CaCO3 due to the carbonation could be large. Further detailed
investigation such as the chemical analysis should be conducted near future.
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and COpore
supercritical
2 structure of cementitous materials exposed to supercritical CO2783

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 10 shows the relationships between the amount of CaCO3 and the depth
from the surface at the 7 day of the exposure. The exposed surface (0-5 mm) of
the OWC had rich CaCO3 content, while the CaCO3 content is smaller at thecenter (20-25 mm) because supercritical CO2 will penetrate gradually from thesurface into the inside of the specimen. On the other hand, the difference in
CaCO3 content at each depth from the surface was not found in the cases of the
FA and OPC. The results are discussed from a view point of Ca(OH)2 content.
The relationships between Ca(OH)2 content and the exposed time of eachspecimens are shown in Figure 11. The figure shows that the remaining Ca(OH)2
content is larger with the distance from the surface until the 3 day of the exposureand all Ca(OH)2 disappeared at the 7 day of the exposure in the case of the OWC
and all Ca(OH)2 disappeared at the 1 day after the exposure in the cases of the
OPC and FA according to the DTA information. Since the amount of CaCO3 still
increase after the disappearance of Ca(OH)2, it is inferred that the carbonation
could proceed to C-S-H gel even at the center. CaCO3 content in the OWC at thecenter is smaller than that at the surface as shown in Figure 10 because thecarbonation progress of C-S-H gel could be small at the center and theprecipitation of CaCO3 by the carbonation could be small while the carbonation of
C-S-H gel is significant at the surface and large amount of CaCO3 was
precipitated, as shown in Figure 9.
On the other hand, however, Ca(OH)2 was not found at all from the surface to thecenter in the cases of the FA and OPC even at one day after the exposure to thesupercritical CO2. It is hypothesized that all Ca(OH)2 could be carbonated fasterdue to the penetration of supercritical CO2 into the center though the cracks in thecase of the OPC, and in the case of the FA, the initial Ca(OH)2 content could besmall because of the pozzolanic reaction and lead to faster carbonation of the
Ca(OH)2. Due to the rapid carbonation of the Ca(OH)2, C-S-H gel in the FA and
OPC could be also carbonated gradually from the surface to the center. As shownin Figure 10, although there was no difference in the amount of CaCO3 between
the surface and center, it is suggested that the increase of CaCO3 due to thecarbonation of C-S-H gel in the FA and OPC could be smaller than that in the
OWC as mentioned above. Since the carbonation proceeded irregularly, especiallyin the case of the OPC, as shown in Figure 8, it could be plausible that the result
could be varied if the collected points are different. Therefore, further studies withusing more samples are necessary near future.
3.1.3 Analysis the variation of the pore distribution due to the mercury
intrusion porosimetry test
The results of the variation of the pore distribution by the mercury intrusion
porosimetry test are shown in Figure 12. The graphs on the left side in figure
shows the pore distribution at the center at the 1 day and 7 day of the exposure,and the right side shows that at the center. At the surface, the distribution peak ofpores with about 100 nm diameter at the 1 day of the exposure moves to the poresize of about 200 nm diameter at the 7 day of the exposure due to the carbonationin all specimens. It is inferred that the pore structure is coarser due to thecarbonation of C-S-H gel and the volume of pores with diameter of over 100 nm
could increase. It could be attributed to not coarsening gel pores and C-S-H gellayer with nanometer pore size but the discontinuous destruction of C-S-H gel

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chains because the micro pore with less than 10 nm diameter had no change
according to the Figure 12.
In the case of center, the pores with diameter of about 100 nm are decreased andFigure 12: Pore distribution after exposure at the surface (left),and center (right)
fine pores with less than 10 nm diameter is not distinct. It is speculated that theslight carbonation of C-S-H gel could not cause the destruction of itself and theprecipitation of the CaCO3 could fill up the capillary pore spaces and make pore
structure denser.

4. CONCLUSIONSThe conclusion in this study is summarized below.

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October
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Hanoi,Hanoi,
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Vietnam(1) When the specimen is exposed to supercritical CO2, it is difficult to identify
the carbonation depth from the surface by the coloring of the phenolphthaleinsolution.
(2) If Ordinary Portland cement is used and exposed to supercritical CO2 underhigh temperature and high pressure, the pore structure become coarser andstrength decrease, and many cracks occur.
(3) In the case of using the FA, the amount of CaCO3 generated by the
carbonation of Ca(OH)2 is small because Ca(OH)2 could be used by the
pozzolanic reaction during the curing and the initial amount of Ca(OH)2 issmall.
(4) If the specimen is exposed to the severe condition such as supercritical CO2, itis suggested that the carbonation could proceed to not only Ca(OH)2 but also
C-S-H gel.
(5) When the specimen is exposed to supercritical CO2 for 7 days, the pore
structure become coarser at the surface and dense at the center.

REFERENCES
1) Preben Randhol, Karen Valencia, Ali Taghipour, Idar Akervoll, Inge Manfred
Carlsen: Ensuring well integrity in connection with CO2 injection, SINTEF
Petroleum Research, NO.936 882 331, 27 December, 2007
2) Sidney Mindess, J. Francis Young, David Darwin: Concrete Second Edition,
Pearson Education, Inc, pp.41-43, 2003
3) H.F.W.Taylor: Cement chemistry 2nd edition, Thomas Telford Services Ltd,
pp.346-348, 1997
4) Barbara G. Kutcko, Brian R. Straisar, David A. Dzombak, Gregory V. Lowry,
Niels Thaulow: Degradation of Well Cement by CO2 under Geologic
Sequestration Conditions, Environ. Sci. Technol. 41, pp.4787-4792, 2007

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Effect of the application of surface
penetrants on the mass transport
properties of concrete
Nozomu SOMEYA1 and Yoshitaka KATO2
1
Doctoral Student, Department of Civil Engineering,
Graduate School of Science and Technology, Tokyo University of Science, Japanj7613701@ed.tus.ac.jp
2
Associate Professor, Department of Civil Engineering,
Faculty of Science and Technology, Tokyo University of Science, Japan
ABSTRACTThis paper presents an experimental study examining the effect of the applicationof silicate-type penetrants on the mass transport properties of concrete made withordinary portland cement or ordinary portland cement incorporating fly ash. The
penetrants were applied to water-cement ratio 0.55 and 0.60 specimens, and themass transport properties (durability) were evaluated by the absorption rate andcarbonation rate. To assist the hydration reaction of the penetrants, calcium
hydroxide was utilized. Silicate-based penetrants were applied to the watercement ratio 0.55 specimens and improved durability against carbonation. In
addition, the application of calcium hydroxide to OPC was found to create good
resistance against carbonation. Overall, the application of silicate-based surface
penetrants was found to affect the depth of carbonation more than it assisted thehydration reaction.
Keywords: silicate-based surface penetrants, improvement effect, carbonation
1. INTRODUCTION
When the performance of a concrete structure is less than the required
performance due to aging and deterioration, the performance needs to be restored
through measures such as repair or reinforcement. Surface penetrants can improvethe durability of concrete and delay the degradation of the structure. In addition,
when applying penetrants at an early age for preventive maintenance, the progressof deterioration can be reduced from the beginning (JSCE, 2005). Silicate-based
surface penetrants are one type of surface protection construction methods, andtheir application to the concrete surface can improve the durability of the concrete.
The application of silicate-based surface penetrants has several benefits such asease of maintenance and the ability to visually check the surface after application.
In past studies, it was found that the effect of silicate-based surface penetrants
varies depending on the quality of the early-age concrete (Hirotake, 2010), and it
was also shown that the penetrants could improve the durability of concrete787

October
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Vietnam
October
2013, Hanoi,
Vietnamcontaining micro-cracks and protect against carbonation. However, it is believedthat the state of the concrete to which the penetrant will be applied is important,and the effect of application on the mass transport properties of concrete isunclear.
This paper presents an experimental study examining the effect of penetrants
which were applied to early-age specimens. The study on early-age specimens
examined the influence on hydration reaction and the difference due to application
timing.
2. EXPERIMENTAL PROGRAM
2.1 Procedure
To understand the effect of application timing on the durability, penetrants wereapplied to specimens aged 7 and 14 days, after which the specimens were placedin a controlled environment (20ºC, R.H. 60%) for 4 weeks. The effectiveness ofan additive (calcium hydroxide) for assisting the hydration reaction was also
examined. Mass transport properties (durability) were then evaluated by the
carbonation rate. The flow for the experiments on early-age specimens is shownin Figure 1
Dry curing
14 days(N-55, FA-55)

Application penetrants-Na, Li
Penetrant at 7, 14day(Dry curing 14 days)

Water curing
14 days(N-60, FA-60)

Application penetrants-Na, Li Assist
Penetrant at 14day(Dry curing 14 days)

Water absorption test
Carbonation test
(Acceleration
at 7,28,56 days)

Figure 1: Flow of testing procedure
2.2 Material and specimens
Table 1 describes the two types of silicate-based surface penetrants and thecalcium hydroxide additive, and the application method was carried out
depending on the penetrant quality. Concrete was made with ordinary portland
cement (density: 3.15g/cm3, Blaine fineness: 3440cm2/g) or ordinary portland
cement incorporating fly ash (density: 2.28 g/cm3, Blaine fineness: 3920cm2/g,
JIS A 6201Ⅱgrade ash). The fine aggregate was river sand (density: 2.61 g/cm3,
fineness modulus: 2.91) while the coarse aggregate was crushed sandstone with
Gmax of 20mm (density: 2.73 g/cm3, fineness modulus: 6.61).
The concrete mix proportions are shown in Table 2. The slump of fresh concrete
was 10±2.5 cm and air content was 4.5±1.5%. The water-cement ratio was 0.55
and 0.60. The water absorption test was carried out on an area of 150×150×150

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ICUS Report 73mm, and the carbonation rate test carried out on an area of 150×150×200 mm.
Specimens were given a surface treatment to limit the number of mass transportsurfaces. Table 3 shows the number of application sides and measurement area ofthe specimens, and an illustration of the specimens is shown in Figure 2.
Table 1: Description of the penetrants and the assisting additive
Code
IngredientApplication quantity (g/m2)
Na
Sodium silicates120
LiLithium silicates
120
Assist Calcium hydroxide
120
Table 2: Concrete mix proportions
Code
N-55
FA-55
N-60
FA-60

W/B
(%)
55
55
60
60

s/a
(%)
45
46
45
52

W
175
175
175
175

C
318
318
318
248

(kg/m3)
F
107
44

S
804
698
804
923

G
1016
1001
1025
888

AE
C*0.002%(C+F)*0.005%
C*0.006%(C+F)*0.013%

Table 3: Details of specimen measurement areas
Measurement area (mm) Application surface
Water absorption test
150*150*150
2 opposing surfaces
Carbonation test
150*150*200
Application sides
150

150
150 or 200 (mm)Figure 2: Illustration of test specimens showing application surfaces
2.3 Test methods
Water absorption test
The water absorption test was carried out according to JSCE-K 572-2012. The
specimen was removed from the testing container seven days after the start of thetest and the mass was measured (Wai) after removing the surface water. Using thisvalue the water absorption rate (Wa) was calculated using Equation (1). The
reported absorption rate is the mean of three values.
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Wa = ( Wai -Wa0 ) / Wa0 ×100

(1)

where, Wa : absorption (%), Wa0 : mass before the examination (g), Wai：mass at
the time of the measurement (g)Carbonation test
The carbonation test was carried out according to JSCE-K 572-2012. The
examination condition used a temperature of 20ºC, R.H. 60%, 5% CO2 density,and the carbonation depth was measured after 7, 28 and 56 days. The carbonation
depth was measured by applying phenolphthalein on the fracture surface, and thereported value was calculated as the mean of six data points, which were
measured twice per specimen (the depth from two opposing sides).
Degree of hydration test
Degree of hydration was evaluated following the manual of the Japan Concrete
Institute using the "degree of hydration test" (JCI, 2005). Specimens wereprepared from mortar with a water-cement ratio of 0.55. Penetrants were applied
to specimens at 3, 7 and 10 days, after which the specimens were placed in acontrolled environment (20ºC, R.H. 60%) until 28 days. The degree of hydration
was determined 28 days after casting.
Ma = (( Mi -M0 ) / M0 ) × 100(2)

where, Ma: degree of hydration (%), Mi: mass after 105ºC drying (g), M0: mass
after 1000ºC drying (g)3. RESULT AND DISCUSSION
3.1 Water absorption test
The results showed that the timing of the penetrant application at 7 days and 14
days affected the water absorption ratio (calculated as the ratio of the test result to
the water absorption rate in the case that no penetrant was applied) as shown in
Figure 3. N-55 experienced improved durability against water absorption, and theabsorption ratio was lower when the penetrants were applied at 14 days than at 7days. FA-55 specimens experienced improved durability against water absorption,and the absorption ratio was lower when the penetrants were applied at 7 days
than at 14 days.
3.2 Carbonation test
Test results examining the carbonation ratio of concrete (56 days) are shown in
Figure 4 and Figure 5. The carbonation ratio is calculated as the ratio of the caseapplying a penetrant to the case with no penetrant. As can be seen in Figure 4, thecarbonation ratio for both N-55 and FA-55 became less than half the ratio of thestandard specimen regardless of the application timing or type.

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1.2

OPC

FA

Absorption ratio

1.0
0.8
0.6
0.4
0.2
0.0

Na7

Na14
Li7
Application timing

Li14

Figure 3: Water absorption ratio (N-55, FA-55)

Carbonation ratio

1.0

OPC

FA

0.8
0.6
0.4
0.2
0.0

Na7

Na14
Li7
Application timing

Li14

Figure 4: Carbonation ratio (N-55, FA-55)
Figure 5 shows the carbonation ratio results looking at different water-cement
ratio and the effect of the assisting additive. In this figure, the experimental results
shown for Na(Li)14 are the same as those given for N-55 and FA-55 in Figure 4.
The results showed that, in the case of N-55 and N-60, the carbonation ratio of N55 was half that of the standard specimen, whereas N-60 without the assisting
additive was the same as that of the specimen with no penetrant. From this result
it is thought that N-55 specimens with penetrants had improved resistance against
carbonation due to an improvement in concrete surface quality. In the case of N60 with calcium hydroxide applied, the ratio was around 80% of that when no
penetrant was applied.
In the case of FA, the carbonation ratio was similar to that of specimens with nopenetrant applied. As can be seen in Figure 5, the application of the silicate-based
surface penetrant with calcium hydroxide did not improve concrete surface quality.
In the FA specimens, calcium hydroxide may have been used up in the pozzolanic
reaction, and thus the carbonation depth of FA specimens with the silicate-based
surface penetrant and calcium hydroxide was not lower than that of OPC
specimens.

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Carbonation ratio

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1.5

Na

Li

FA

OPC

1.0
0.5
0.0

No Assist No
assistassistNo Assist No
assistassist

N-55

FA-55

N-60

FA-60

Figure 5: Carbonation ratio (N-55, N-60, FA-55, FA-60)
The relationship between carbonation depth and square root of time is shown in
Figure 6 for N-55. In the case of no penetrant application a linear relationship canbe seen. However, in the case of Na14, the data deviates from the linear
relationship at around 40 days. Based on this result, it is possible that the
carbonation depth exceeded the improvement depth. The improvement depth (Y)due to application of silicate-type penetrants can be calculated using Equation (3).
Y = ( Bp / Bc ) / H(3)

where, Y: improvement depth (  penetration depth) (mm), H: carbonation depth
for no penetrant application (mm), BC: carbonation rate for no penetrant
application (mm/√day), BP: carbonation rate for penetrant application (mm/√day)

Carbonation depth(mm)

15

Na14
No penetrant
Linear - No penetrant

10

y = 1.1√t5

y = 0.4√t
0

0

2

4
6
Square root time(√day)8

Figure 6: Progress of carbonation depth over time (N-55)
Improvement depth is shown in Table 4. The calculation could not be carried out
for N-60 and FA-60 because the carbonation depth already exceeded theimprovement depth. The results showed that the improvement depth becamearound 2 to 3 mm for N-55 and around 1 to 2 mm for FA-55. In the case of thesodium-type silicate application, the difference between concrete types appears to792

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be large, whereas for lithium-type silicate the penetration depth is around thesame for the two concrete types. In previous studies, the penetration depth wasreported to be around 20 mm from the surface (Takayuki, 2011). Therefore, theaffected depth found in this experiment was lower than that in previous studies.
Table 4: Improvement depth calculation result

Na7
Na14
Li7
Li14

Improvement depth (mm)
N-55
3.2
3.2
1.8
2.2

FA-55
0.9
1.0
2.0
1.9

3.3 Degree of hydration test
Based on the results in the previous sections, it can be understood that the effectof application timing on the water absorption ratio is different from the effect on
the carbonation ratio. In order to understand this phenomenon, the degree ofhydration test was conducted.

Degree of
Hydration ratio

The hydration ratio results for the sodium-type silicate (N-55) are given in Figure
7. The hydration rate at 10 days is relatively higher than the standard material
since the amount of calcium hydroxide is higher at 10 days compared to 3 and 7
days. From the water absorption rate and degree of hydration test results, it isbelieved that application of the sodium-type silicate penetrant at 14 days to the
OPC specimen resulted in the greatest concrete surface improvement. Therefore,
the water absorption ratio was improved because of the progress of the penetrant
reaction. On the other hand, the carbonation ratio was not improved due to theconsumption of hydroxide by the penetrant reaction.

1.5
1.0
0.5
0.0

3days
7days
10daysApplication timing

Figure 7: Hydration ratio for sodium-type silicate penetrant (N-55)

Effect of the application of surface penetrants on the mass transport properties ofEffect of the concrete
application of surface penetrants on the mass transport properties of concrete793

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CONCLUSION
The effect of the application of silicate-based surface penetrants on the masstransport properties of concrete was experimentally examined. The results are
summarized as follows.
1) When comparing OPC specimens with FA specimens, it could be seen thatapplication was more effective at 14 days for OPC specimens but more
effective for FA at 7 days.
2) Silicate-based surface penetrants were applied to the water-cement ratio
0.55 specimens and improved resistance against carbonation. In addition,
the application of calcium hydroxide to OPC was found to create good
resistance against carbonation.
REFERENCES
Hirotaka, H., Kouji, T., Toshinobu, Y. and Nao, S. (2010). "Fundamental Studyon Performance and Difference of Various Surface Improvement Material."
Proceeding of the Japan Concrete Institute, 48(5) 1619-1624. (in Japanese)
Japan Concrete Institute (JCI). (2000). Examination and analysis manual of theconcrete, Study on long-term durability Committee of concrete. (in Japanese)
Japan Society of Civil Engineers (JSCE). (2005). Recommendation for Concrete
Repair and Surface Protection of Concrete Structures, Concrete Library 119. (inJapanese)
Takayuki, S., Kouji, T., Toshinobu, Y. and Hirotaka, H. (2011). "Effects ofsurface improvement material on chloride panetration and neutralization."
Proceeding of the Japan Concrete Institute, 33(1), 1625-1630. (in Japanese)
Torrent, R. (1992). "A two-chamber vacuum cell for measuring the coefficient of
permeability to air the concrete cover on site." Proceeding of the Materials andStructures, 25, 358-365.

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Influence of coexistent ions in seawateron the chloride permeability of concrete
Toshiya CHIBA1, Katsuya MITA2 and Yoshitaka KATO3
1
Master student, Department of Civil Engineering,
Graduate School of Science and Technology, Tokyo University of Science, Japantoshiya1350@gmail.com
2
Assistant Professor, Department of Civil Engineering,
Faculty of Science and Technology, Tokyo University of Science, Japan
3
Associate Professor, Department of Civil Engineering,
Faculty of Science and Technology, Tokyo University of Science, Japan
ABSTRACT
There has been considerable research on the penetration of chloride in concrete.
However, most of these works focused on the permeation of only chloride ions in
concrete, but the actual composition of seawater contains not only chloride but
also different kinds of ions such as magnesium, calcium, potassium and sulfate,and concrete structures in marine environments are affected by all these types ofions. This study discusses the effects which various ions in seawater exert on thechloride permeability and diffusion in concrete through an experimental study inwhich we measured the salt concentration in concrete and depth of chloride
penetration obtained using AgNO3 solution spray method. The results showed thatthe sulfate ions, potassium ions and magnesium ions contained in seawaterpromote the penetration of chloride ions in concrete.
Keywords: chloride ion, sulfate deterioration, diffusion coefficient, pore volume
distribution
1. INTRODUCTION
Concrete structures in marine environments suffer a variety of complex
deterioration such as steel corrosion due to penetration of chloride ions fromseawater, frost damage deterioration in cold climates and physical erosion caused
by waves and tides. When further considering the chemical erosion of thehardened cement matrix, it is clear that sulfate salt and magnesium chloride erode
concrete and affect the chloride permeability of concrete (Kumar, 2000).
The amount of salt contained in concrete is measured from crushed concrete
samples following JCI-SC4. It has been confirmed that the analytical method canmeasure the chloride ion concentration with high accuracy, but it involves
extensive labor, the analysis period is long, and the procedure is expensive, so it isdifficult to measure the chloride ion concentration of many concrete samples. On
the other hand, the AgNO3 solution spray method is another means for measuring795

October
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immediately and visually measured.
With the AgNO3 method, the depth of chloride penetration is measured by the useof a white silver chloride produced by the reaction between chloride ionscontained in concrete and a sprayed aqueous silver nitrate solution (Nobuaki,1990). However, there is little knowledge available on the quantitative chloride
ion concentration at the boundary of the white discoloration. In addition, paststudies only tested with immersion in salt water, and thus studies considering theeffect of other ions in seawater are few. Given the above, it is important toexperimentally investigate the effect of other ions in seawater on the AgNO3
solution spray and quantitatively consider the applicability of the AgNO3 solution
spray in a real ocean environment using the measurement results of thepotentiometric titration.
This study experimentally examined the penetration and spread of chloride ionscontained in seawater via two methods: measurement of the depth of chloride ion
penetration using the AgNO3 solution spray method and analysis of the chloride
ion content.
2. EXPERIMENTAL OUTLINE
2.1 Material and specimens
The cements used in this study were ordinary portland cement (symbol C, density
3.15 g/cm3) and blast furnace cement Type B (symbol BS, density 3.04 g/cm3).
The aggregates used were Yamanashi Fujikawa river sand (symbol S, density 2.61
g/cm3) and Chichibu (Saitama Prefecture) crushed stone (symbol G, density 2.72
g/cm3). The mix proportions are shown in Table 1. The prepared specimens wererectangular columns (10 × 10 × 8.5 cm).
Table 1: Concrete mix proportions
Code

W/C(%)

OPC50
BS50

50
50(BS)

s/a
(%)
45
46

W
175
175

C
350
193

(kg/m3)S
BS Gyp
0
0
783
151
7
794

G
998
971

Ad
1.75
3.51

2.2 Experimental conditions
The specimens were demolded and cured for 28 days in water, then coated withepoxy resin except for the surface to be exposed to the immersion solution.
Specimens were then immersed in either an NaCl aqueous solution or one of four
mixed solutions for 56 and 91 days. The mixed solutions were made by dissolving
sulfate-adjusted cations to concentrations based on seawater composition. The
NaCl solution was mixed at 10% weight percent concentration. The types of
sulfate dissolved were MgSO4, CaSO4, K2SO4 and Na2SO4 at percent

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concentrations of 0.61%, 0.38%, 0.21%, and 0.01%, respectively. The ion
concentrations of the four mixed solutions are shown in Table 2.
Table 2: Ion concentrations in the mixed solutions

ClNa+
SO42Mg+
Ca2+
K+

Four kind of mixed solution (mol/l)
Mixed
Mixed
Mixed
Mixed
solution of solution of solution of solution of
MgSO4
CaSO4
K2SO4
Na2SO4
1.71
1.71
0.051
0.028
0.012
7.00×10-4
0.051
0
0
0
0
0.028
0
0
0
0
0.012
0

2.3 Potentiometric titration
The total chloride ion amount and soluble chloride ion amount contained in theconcrete samples were measured by the potentiometric titration according to JCISC4. The soluble chloride ion was extracted with hot water at 50°C. The concrete
samples were collected from mortar at varying distances from the exposure
distance: 0-10 mm, 11-20 mm, 21-30 mm, 31-40 mm and 41-50 mm. The
preparation method of the samples is shown in Figure 1.

Figure 1: Sample preparation method
2.4 Pore diameter distribution measurement
Parts of mortar samples were used for measuring the pore size distribution by
mercury intrusion porosimetry (MIP). The MIP specimens were collected fromthe sample surface and crushed to a size of 2.5-5 mm. They were then immersedin acetone to stop the hydration reaction, and the pore size distribution wasmeasured after drying by the D-dry method.

Influence of coexistentions
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the chloride
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2.5 AgNO3 solution spray method
The AgNO3 solution spray method was applied to measure the depth of chloride
ion penetration. The specimen was split along its vertical axis and the cracked
surface was sprayed with AgNO3 aqueous solution (0.1mol/l). The penetration
depth could then be measured as the depth of the white coloring of the silver
chloride. This method measures the depth of the soluble chloride ions.
3. RESULTS AND DISCUSSION
3.1 Total chloride ion concentration
The measurement results of the total chloride ion concentration in OPC50
immersed for 91 days in each solution are shown in Figure 2. When looking at thethe region of 0-10 mm, the chloride ion concentration increases in the order ofpotassium sulfate mixed solution, sodium sulfate mixed solution, magnesium
sulfate mixed solution, NaCl aqueous solution, and calcium sulfate mixed solution.
Figure 3 shows the measurement results for BS50 immersed 91 days. The amountof chloride ions for the potassium sulfate mixed solution and sodium sulfate
mixed solution was high in the region of 0-10 mm. However, penetration ofchloride ion after the region of 10-20 mm was not observed. Since the chloride
ions are present in the region of 10-20 mm and 20-30 mm in OPC50, theinhibitory effect of blast furnace slag on chloride ion penetration was confirmed.
Using the chloride ion concentration distributions shown in Figure 2 and Figure 3,
the apparent diffusion coefficient (Da) and surface chloride ion concentration (C0)from a theoretical solution of the Fick’s diffusion equation under conditions ofconstant surface concentration were calculated. By using the result, the number ofyears until reaching the limit concentration (Clim) for generating steel corrosion
could be calculated, and compared with the ease of chloride ions penetration. The
Clim of OPC50 in this experiment was 1.9kg/m3, following the 2012 JSCE
Standard Specification for Concrete Structures, and the number of years leading
up to the Clim for 5 cm cover depth was calculated.
The results are shown in Table-3. The sulfate mixed solutions except for calcium
sulfate mixed solution reached Clim earlier than the NaCl aqueous solution. It is
possible that sulfate, the main cause of sulfate deterioration in concrete, affected
the salt permeability. In the case of sulfate mixed solutions, it is estimated thatchloride ions easily penetrated into concrete due to sulfate deterioration, andresulted in subtle cracking and weakening that cannot be confirmed by visualobservation (Yoshida, 2011). However, for calcium sulfate mixed solution, salt
penetration was suppressed. This behavior may be due to differences in theelution amount of calcium ions from the concrete surface. According to Imoto(2004), the elution of calcium ions lowered the C/S of C-S-H in the concrete,leading to weak C-S-H with high void volume. It is thought that the calcium
sulfate mixed solution suppressed the elution of calcium ions because, in calcium
sulfate mixed solution, there are more calcium ions than in the other mixed
solution and the difference in the concentration of calcium ions between the pore

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solution and soaking solution is small. The apparent diffusion coefficient of thespecimens immersed in magnesium sulfate mixture was large, which may have
led to the magnesium ion and sulfate ion, the main cause of sulfate deteriorationin seawater, affecting the salt permeability of concrete. Due to the presence ofmagnesium ions, calcium sulfate and magnesium hydroxide are produced on theconcrete surface, and lead to the formation of MSH and generation of ettringite(Yamaji, 2008). It is believed that the expansion pressure of ettringite leads todegradation, thus allowing easier penetration of chloride ions into concrete.

Figure 2: Total chloride ion concentration Figure 3: Total chloride ion concentrationin OPC50
in BS50

Table 3: Diffusion coefficient, surface chloride ion concentration and the numberof years leading up to the Clim
Immersion
solution typeMgSO4
Na2SO4
K2SO4
CaSO4
NaCl

DiffusioncoefficientDa（cm2/year）
2.3
1.8
1.7
1.7
0.8

Surface chloride
ion concentration
C0（kg/m3）
14.5
22.3
26.1
4.7
19.5

Time
（year）
2.3
2.2
2.2
10.0
5.6

3.2 Pore diameter distribution
The cumulative pore volume distribution and differential pore volume distributionof OPC50 immersed NaCl aqueous solution and sulfate mixed solution are shownin Figure 4 and Figure 5.
The pore structure appears different depending on the immersion solution. For thepore diameter of 100 nm or less the cumulate intrusion decreases in the order offresh water, NaCl aqueous solution, and sulfate mixed solution; that is, NaCl

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the chloride
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Vietnamhydrate generated by sulfate deterioration. Therefore, in this study it is assumed
that the filling of the pores was due to ettringite and gypsum. However, this iscontrast to the effect of sulfate on the salt permeability obtained in Section 3.2, as
densification of the pore structure should suppress the penetration of chloride ions.

Figure 4: Cumulative pore volume
distribution

Figure 5: Differential pore volume
distribution

3.3 Study on the AgNO3 solution spray method
The measurement results of the chloride ion penetration depth using the AgNO3
solution spray method are shown in Figure 6 and Figure 7. It can be clearly seenthat blast furnace slag and immersion solution affected the chloride ion
permeability in concrete. From these results, it can be said that concrete
specimens with blast furnace slag had improved water tightness and were bettershielded against chloride ion penetration. When comparing the depth of chloride
ion penetration by the AgNO3 solution spray method with the chloride ion
concentration distribution shown in Section 3.1, there appears to be a difference inthe effect of the solution species on the salt penetration. It was reported by Otsuki(1990) that concrete sprayed with the AgNO3 solution became colored white due
to reaction with the soluble chloride ions, and in the case of an AgNO3 solution of
0.1 mol/L the amount of soluble chloride ion of the coloring limit isapproximately 0.15% of the unit cement content. Therefore, based on themeasurement results of the soluble chloride ion concentration, the concentrationof color limit was determined.

Figure 6: Depth of chloride ion
penetration OPC50

800

Figure 7: Depth of chloride ion
penetration BS50

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Soluble chloride ion concentration [kg/m 3 ]The relationship between the concentration color limits with soluble chloride ion
concentration under immersion in an NaCl aqueous solution is shown in Figure 8.
Then, assuming that Cb is the soluble chloride ion concentration at the color limit,
the location where the soluble chloride ion concentration distribution (represented
by the curved line in Figure 8) intersects the depth of chloride ion penetration(measured by the AgNO3 solution spray method, shown as the vertical line) is
considered to be Cb. Assuming Ca as the soluble chloride ion concentration in thecolor limits based on the study of Otsuki (1990), since the unit cement content of
OPC50 is 350 kg/m3, Ca could be calculated as 0.525 kg/m3 and Cb then calculated
as 1.81 kg/m3. However, the measurement results does not match with the Ca
obtained by Otsuki. In a similar manner, the Cb of the other immersion solutions
were calculated along with the percentage of the unit cement content, as shown in
Table 4. Cb is more than twice as large as Ca, and differed by immersion solution.
24
21
18
15
12
9
6
3
0

NaCl
The depth of chloride
ion penetration
Cb
Ca

0

1

2

3

4

Distance from the surface[cm]5

Figure 8: Relationship between the concentration color limits with soluble
chloride ion concentration
Table 4: Cb and calculated percentage of unit cement content
Value obtained by
Otsuki (1990)
MgSO4
Na2SO4
CaSO4
K2SO4
NaCl

Cb [kg/m3]

Cb/Ca

C× x [%]

0.525

1

0.15

1.24
1.06
1.45
1.38

2.36
2.02
2.80
2.63

0.35
0.30
0.41
0.39

1.81

3.45

0.51

4. CONCLUSIONS
The results of this study are summarized as follows.
 The penetration of salt is different from that of the NaCl aqueous solution andsulfate mixed solution, and it was found that the total chloride ion
concentration in concrete exposed to potassium sulfate mixed solution, sodium
sulfate mixed solution and magnesium sulfate mixed solution was large.
Influence of coexistentions
in seawater
the chloride
permeabilityof concrete of concrete
Influence ofcoexistentions onin seawateron thechloride permeability

801

October
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October
2013, Hanoi,
Vietnam From the pore size distribution measurements, exposure to the sulfate mixed
solution may lead to a denser pore structure. However, densification of the pore
structure is estimated to suppress the penetration of chloride ions, and so it isinconsistent that the total chloride ion concentration in the sulfate mixed
solution was larger. In the future, it is necessary to consider the mass transferof sulfate deterioration.
 From the calculation results of the soluble chloride ion concentration from thecolor limit of the AgNO3 solution spray method, the soluble chloride
concentration Cb at the color limit did not match the soluble chloride ion
concentration of Ca referred to in previous studies.
REFERENCES
P. Kumar. (2000). “Concrete Microstructure, Properties, and Materials.” Gihoudo
Shuppan. (in Japanese)
Otsuki, O. (1990). Evaluation of the AgNO3 Solution Spray Method for
Measurement of Chloride Penetration into Hardend Cementious Matrix Materials,
Technical Report No.42, Tokyo Institute of Technology.
Yoshida, N. (2011). Deterioration of concrete due to crystal growth of sodium
sulphate, GBRC, Vol.36, No.3, pp.13-22.
Imoto, H. Japan Concrete Institute (JCI). (2004). Leaching Property of Odinary
Portland Cement Hardend Paste in Sodium Chloride Aqueous Solution, Vol.26,
No.1, pp.903-908.
Yamaji, T. Japan Concrete Institute (JCI). (2008). Result of concrete quality inexisting structures eposed under marine environment for long term, Vol.30, No.1.
Kawaura, J. (2009). Japan Concrete Institute (JCI). Analytical study of change theamount of pore regenerating ettringite by sulfate erosion, Vol.31, No.1, pp.859864.

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Performance of crack self-healing concrete bydevelopment of semi-capsulation techniquefor functional effective ingredients
Vu Viet Hung1, Toshiharu Kishi2, Tae-Ho Ahn3
1
Doctor candidate, the University of Tokyo, Japanvhung@iis.u-tokyo.ac.jp
2
Professor, IIS, the University of Tokyo, Japan
3
Assocciate Professor, IIS, the University of Tokyo, Japan
ABSTRACTIn this study, concrete was designed with a crack healing capability, in which acrack of 0.2-0.4mm width could be self-healed by activating reactions between
embedded granules and external water upon cracking. Trial of granules
containing Portland cements & some specific self-healing additives manufactured
by semi-capsulation technique was developed based on the basic design conceptof self-healing materials (proposed by Ahn, 2008) and the granulation technique(proposed by Koide & Morita, 2010). Self-healing granules were added to theconcrete mixture by partial replacement of sand. In this experiment, the capabilityof crack self-healing concrete was assessed by observing the time-dependent
reduction of water leakage through a crack, the closing process of surface crack
and chemical analysis of deposited products.
From the experimental investigation, it was concluded that the designed concrete
possesses an excellent crack self-healing performance, in terms of recovery ofwater tightness property and crack closing process after cracking and long-termpreservation of its capability by development of semi-capsulation technique forfunctional effective ingredients. Moreover, there is a promising possibility tobroadly apply this concept to practice in order to improve the durability andfunctionality of civil infrastructures, such as water retaining and undergroundstructures.
Keywords: concrete, self-healing, granule, crack, semi-capsulation.
1. INTRODUCTION
In structures subject to contact with water, such as water-retaining structures,
tunnels or basements, crack appearance and water leakage are common
phenomena. A penetrated crack causes a significant reduction in the durability,
functionality/serviceability and aesthetics as well. In these structures, watertightness and durability are of paramount importance. There are several
conventional methods to achieve the watertight property of concrete structures,for examples, application of waterproofing treatment on the surface (for newly
constructed structures) or injection of filler material after cracking (for repaired
structures), etc. However, it often increases the cost, lengthens construction period803

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamand also interferes with the normal service of the structure. Therefore, it inspires
the possibility that; if concrete were designed with a sufficient healing capability,
cracks in concrete can be self-healed to recover the water tightness property andimprove the durability of concrete structures without human intervention.
In general, concrete/cementitious composite has a certain healing capacity(Edvardsen, 1999; Heide, 2005; Hirozo, 2012; etc.). Unfortunately, its capability
is limited and uncertain in most circumstances (Reinharddt, 2003; etc). Recently,
there are various approaches being developed to improve the healing ability ofconcrete. For instances, it can be listed as fiber reinforced (Lepech & Li 2009;etc.); bacteria-based (Wiktor & Jonkers 2011; Wang 2012; etc.); polymer, epoxy
or glue resin, etc. (Mihashi 2000; Kessler 2003; Joseph C. 2009; etc.).
Another approach introducing self-healing capability to concrete at a normal
water/cement ratio was proposed by Ahn, 2008. Some specific mineral andchemical admixtures in terms of swelling, expansion and precipitation were added
to concrete mixture in form of powder as partial cement replacement. Even
though the self-healing performance was promising, there were somedisadvantages in this approach, such as the reduction in workability and the selfhealing efficiency due to further reactions between self-healing powder andmixing water. To overcome the above mentioned drawbacks, the self-healing
granules having semi-capsulation effect, in which the inner material containing
self-healing materials were coated by cement compound, were developed by
Koide & Morita, 2010. Originally, this conventional granulation technique was
widely used in the food/medicine industry. Therefore, the manufacturing cost was
high. Moreover, due to immature technology and lack of design concepts at thatmoment, the performance of self-healing concrete containing granules was not sosignificant compared to the powder type approach. However, it is a preferable
approach to introduce self-healing properties to concrete. Thus, it is necessary todevelop a semi-capsulation technique for powder material.
2. OBJECTIVES
Based on its own advantages and high potential to improve the healing
performance and manufacturing cost, self-healing granules having semicapsulation effect were chosen as a research approach in this study. The
objectives are to propose basic design concepts of granules having semicapsulation effect, and to improve the self-healing performance of granules in
concrete by enhancing the semi-capsulation technique with considerations ofsimple & cheap granule fabrication.
3. BASIC DESIGN CONCEPTS OF GRANULES HAVING SEMICAPSULATION EFFECT FOR POWDER MATERIAL
Even though the concept of self-healing granules having semi-capsulation effect
was proposed by Koide & Morita, self-healing performance of concrete
incorporating granules was not as good as expected in previous research. Firstly,
it is thought to be due to the high strength of granules. As a result, when a crack
penetrates into the concrete matrix, granules can not be broken as seen in Figure804

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1a. Secondly, the hardened condition of inner material in/after the granulation
process or the surface of broken granules when contacting to water flow isbelieved to reduce the self-healing capacity (Figure 1b). Given this condition,even if granules are ruptured by crack penetration, the inside self-healing
additives are thought to be difficult to dissipate into the crack surface and thisrestrains the healing capability.

Figure 1: (a) Unbroken granule; (b) Hardened state of inner material
Based on the results obtained from the research of Koide & Morita (2010), it canbe found that granules made by conventional granulation method do not fulfill therequirements of granules having semi-capsualtion effect. In order to achieve this,basic design concepts of granules for powder material are established in this paper,as follows:
3.1 Concept 1: Granule should have waterproofing property
A coating layer will be introduced to granule to render the surface impermeable towater. Even though the coating layer is made by cement compound, it is possible
to control the water absorption of granule and further reactions between
ingredients of granule and mixing water by producing an effective outer layer,
which has good bonding property with concrete matrix, enough strength andthickness and watertightness property to protect inner material.
3.2 Concept 2: Granule containing inner self-healing material should bestrong enough to preserve the healing capability from unexpected events
during concrete mixing process and also should be weak enough to be
cracked when necessary.
This means that an appropriate strength of inner material should be obtained.
Being broken and released when needed is a very important aspect for granules tofulfill the semi-capsulation effect. The strength of granule, mainly contributed by
the strength and thickness of the coating layer, should be strong enough towithstand the compaction/vibration effect while mixing and casting concrete.
However, the outer layer also should not be too strong and thick as well. In
addition, the inner material should be weak enough and easily released after
rupture to ensure the spreading effect.

of crack self-healing
concrete by developmentof semi-capsulation
PerformancePerformanceof crack self-healing
concrete by developmentof semi-capsulation
techniquetechniquefor
functional
effective
ingredientsfor functional effective ingredients805

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4. EXPERIMENTAL PROGRAM
4.1 Self-healing materials
Based on the basic design concepts mentioned-above, specific materials arechosen to manufacture self-healing granules as can be seen in Figure 2. Table 1
shows the ingredients of self-healing granule in percentage. In this trial, selfhealing additives are composed of swelling, expansion and precipitation materials,
based on the basic design concept of self-healing material (proposed by Ahn,
2008).
Coating material

Protection effect

Waterproofing effectSufficient thickness & strength

Dense layer

Rapid hardening material(Portland cement compound of Early high strength cement & Low-heat cement)
Inner material

Spreading effectSelf-healing effectPortlandcements

Self-healing
additives

Water-soluble agent(or water-reducing agent)Hydration

Swelling/
Expansion/
Precipitation

Easy dissolution(or hydration restraint)

Self-healing
capability
Figure 2 Strategies to select the materials of granule806

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Table 1: Ingredients of self-healing granule

4.2 Semi-capsulation techniques
In this experiment, there is an effort to manufacture self-healing granules by usinga typical concrete mixer in laboratory (drum mixer or roller mixer). Granules are
made through a granulation process as following:Firstly, the inner granule manufacture is prepared by gradually adding the selfhealing powder and spraying the liquid in the drum mixer as seen in Figure 3. Dueto this procedure, it is assumed that flocs of self-healing powder will be loose or
weak (just pointed or small area of surface contact with each other) so that it iseasier to be broken and diffuse out of the granule.
Secondly, a coating layer build-up is followed by continuously adding coating
materials and spraying the liquid in the drum mixer. And then after curing inplastic boxes for a few days, pre-fabricated granules are steamed (Figure 3).
Under the effect of steaming: high temperature & moisture, it is expected that adense & hardened coating layer will be formed by the hydration products of
cement compound. This layer will protect the weak inner material and also createa barrier that makes it difficult for water to pass through.

Figure 3: Granulation techniques
Typical sample and particle size distribution of self-healing granules also can beseen in Figure 4. From this figure, it can be found that about 80% of granules
could pass the seive of 2.36mm. Therefore, it is expected that the distribution of
granules in concrete matrix will be improved compared to past research. Theof crack self-healing
concrete by developmentof semi-capsulation
PerformancePerformanceof crack self-healing
concrete by developmentof semi-capsulation
techniquetechniquefor
functional
effective
ingredientsfor functional effective ingredients807

October
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Hanoi,Hanoi,
Vietnam0ctober
Vietnamsmaller in size the granules are, the higher the possibility that a crack ruptures
them, and the higher the healing capacity of concrete.

Figure 4: Typical sample & particle size distribution of granules
4.3 Experimental flow & techniques to verify self-healing performance
After fabrication in the laboratory, the granules were transported to a ready-mixed
concrete plant for casting cylindrical concrete specimen (100mm diameter x
200mm height). Concrete was cast with a water/cement ratio of 49.6% and selfhealing granules were incorporated as partial sand replacement at a dosage of 70
kg/m3 of concrete (Table 2). After casting, concrete specimens were cured under
three different regimes i.e regime one R1 (cured in water at 40oC for one monthshort term range), regime two R2 (cured in air at 20oC, relative humidity of 60%
for twelve months-long term range) and regime three R3 (cured in water at 40oC
for nine months and then in air at 20oC, relative humidity of 60% for threemonths-long term range). The purpose was to investigate the self-healing
performances of concrete incorporating granules with the elapsed time under
different exposure conditions.
Table 2 : Mix proportion of self-healing concrete
W/C
s/a
Gmax
Air
W
NC
SH Granule
S
G
3
(%)
(%)
(mm) (%)
kg/m
49.6
51.3
20
4.5
175 35370
830 869(Note : W-water; NC-Ordinary Portland Cement; S-sand; G-gravel)
In this study, the water pass test, described by Morita (2010), was used toquantitatively evaluate the self-healing performance as water leakage control.
After curing, a penetrating crack was induced to the concrete specimen by
applying tensile splitting load. The internal crack was controlled to around 0.2mm
by the thickness of Teflon sheet, while the surface crack width was measured by
microscope at three different spots. The average value of those spots was adopted
as the surface crack width, ranging from 0.2-0.4mm (Figure 5a). In thisexpermient, a continuous water supply was conducted until 56 days to stimulate
the chemical and other reactions in the crack (Figure 5b). It was assumed thatonce crack occurred, the embedded granules were broken. And when water
flowed through the crack, not only did the self-healing materials get diffused into

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crack surface but also the cement hydration products were dissolved in flowing
water. Over time, the crack in concrete was healed & water leakage stopped,
mainly due to the formation of new products.
The self-healing performance of concrete was evaluated by the water passing test,in which the water leakage through a crack under pressure of approximately eight
centimeters water head and the crack closing process observed by microscopewere measured periodically (Figure 5c). Moreover, analysis of chemicalcomponents of healing products precipitated at the crack was also conducted by
Thermogravimetry-Differential Thermal Analysis (TG-DTA) and X-Ray
Fluorescence (XRF).

(b)

(a)

(c)

Figure 5: (a) Surface crack width; (b) Exposure condition; (c) Water pass test
In order to observe the time dependent permeability of a cracked concrete, thewater flow rate was measured and calculated by the formula (1), on the specificdays until 56 days subjected to continuous water flow.
FRi 

V5 min,it(1)where: FRi-water flow rate on i days [cm3/sec]; V5min,i-volume of water flowing
through a crack in five minutes on i days [cm3]; t-period of testing, in this test
t=300sec.
Furthermore, to assess quantitatively the decreasing flow rate with time, flow
relative to initial flow was introduced as in formula (2):RFRi 

FRi
FR0

(2)

where: RFRi- relative flow rate on i days [%]; FRi- water flow rate on i days
[cm3/sec]; FR0- initial water flow rate on starting day of testing [cm3/sec].

of crack self-healing
concrete by developmentof semi-capsulation
PerformancePerformanceof crack self-healing
concrete by developmentof semi-capsulation
techniquetechniquefor
functional
effective
ingredientsfor functional effective ingredients809

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5. EXPERIMENTAL RESULTS & DISCUSSIONS
5.1 Result of water flow rate through a crack with time

Water flow rate (cm3/sec)

The results showed that there was an insignificant difference of healing capability
under three different curing regimes. The same tendency of reduction in waterleakage and healing products deposited on the surface crack were observed withtime even though the initial flow rates were relatively different (Figure 6). It could
be seen that the water leakage after one day exposed to water flow was just about
10% of initial water flow and then after one week exposure, the water flow wasalmost stopped during the permeability test as clearly seen in Figure 6.
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0

R1-W40-1M
R2-A20RH60-12M
R3-W40-9M&A20RH60-3M

0

1

3

7

14 21 28 35 42 49 56

Duration exposed to water flow (days)
Relative flow rate (%)

120

R1-W40-1M
R2-A20RH60-12M
R3-W40-9M&A20RH60-3M

100
80
60
40
20
0

0

1

3

7

14 21 28 35 42 49 56

Duration exposed to water flow (days)
Figure 6: Water flow rate & relative flow rate with time
5.2 Result of crack-closing process at the bottom surface
Moreover, it was found that the crack closing process was mainly observed at thebottom of testing specimen by the substantial amount of white deposits forming at
crack mouth (Figure 7). A possible reason was that under the effect of flowing
water, there was a higher concentration of both calcium and carbonate ions, higher
pH value of flowing water and also slower water flow rate at this area, facilitating
the precipitation of calcite or other healing products.

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R1-W40-1M

0D

R2-A20RH60-12M

7D

14D

28D

56D

Figure 7: Crack closing process
5.3 Chemical analysis of deposited products at crack
After the water pass test at 56th day under continuous water supply, the specimens
were kept in room conditions (T=20oC & RH=60%) for a few days. The two
halves of specimens were then split again by removing silicone rubber in order toobserve the condition of inner crack surface. Moreover, healing products at thebottom of concrete specimen were examined to verify the chemical component by
TG-DTA test. The result showed that the healing products at this zone weremainly composed of calcite as expected. Additionally, it was found that thehealing products deposited on the surface of aggregate were mainly composed ofcalcium compounds based on the result of XRF test.
6. CONCLUSIONS & FURTHER RESEARCH
In this research, the normally used water/cement ratio concretes were designedwith the self-healing capacity by incorporating the granules of Portland cements,
other additives and a specific water-soluble agent (or also water-reducing agent),
considered as a type of engineered self-healing approach. Especially, two basic
design concepts for granules having semi-capsulation effect and improvement interms of simple & cheap granule fabrication were proposed and established.
Based on the experimental results, it can be found that under certain laboratory
conditions (static crack of 0.2-0.4mm, continuous water supply), concrete
containing self-healing granules of functional effective ingredients is promising tomaintain the self-healing ability of concrete, with respect to recovery of watertightness properties, for both short term and long term exposure. Crystalline
healing products were gradually formed on the crack surface and thus
significantly reduced or completely stopped the water leakage with time. This
Performance of crack self-healing concrete by development of semi-capsulation
Performancetechniqueof crack self-healing
concretebyingredientsdevelopment of semi-capsulation techniquefor functional
effective
for functional effective ingredients811

October
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Vietnamapproach may be suitable for self-healing of underground or water retaining
structures where continuous water supply may be expected.
Furthermore, this approach showed a high potential to introduce self-healing
concrete to the practical construction due to its feasibility in mass production of
granules and concrete with considerations of simple & cheap manufacture.
However, further research is needed to verify and confirm the roles of each
ingredient of granule on its semi-capsulation effect. In order to apply this material
in real structures, further test with different exposure conditions and types ofstructures should be performed, such as wet/dry conditions, high pressure water,water submersion, period of crack appearance and exposure to water, size or
dimensions of specimen, crack pattern or crack initiation, etc.
REFERENCES
Ahn, T. H., 2008. Development of self-healing concrete incorporating geomaterials: A study on its mechanism and behavior in cracked concrete. Doctor
thesis, the University of Tokyo, Japan.
Morita, S., Koide, T., Ahn, T.H., and Kishi, T., 2010. Evaluation of performance
upgrade for the cracked self-healing concrete incorporating capsuled inorganic
materials, JCI-TC091A, 183-190 (in Japanese).
Edvardsen, C., 1999. Water permeability and autogenous healing of cracks inconcrete, ACI, 96(4), 448-454.
Heide, T. N., 2005. Crack healing in hydrating concrete, Msc-thesis, Delft
University of Technology, The Netherlands.
Hirozo, M., and Tomoya, N., 2012. Development of engineered self-healing andself-repairing concrete –State- of –the- art Report, ACT, 10, 170-184.
Reinhardt, H. W., Jooss M., 2003. Permeability and self-healing of cracked
concrete as a function of temperature and crack width, Cement and Concrete
Research, 33(7), 981-985.
Yang, Y.Z, Lepech, M.D., Li, V.C., 2009. Autogeneous healing of engineered
cementitious composites under wet-dry cycles, Cement and Concrete Research
39(5), 382-390.
Jonkers, H.M., Bacteria-based self-healing concrete, Heron, 56(1/2),1-12
Jonkers, H. M., Towards a sustainable bacterially mediated self-healing concrete,
Delft University of Technology, the Netherlands.
Wiktor, V., 2011. Assessment of the crack healing capability in bacteria-based
self-healing concrete, Conference on Self-healing materials, UK.
Wang, J., van Tittelboom, K., De Belie, N., Verstraete, W., 2012. Use if silica gelor polyurethane immobilized bacteria for self-healing concrete, Construction and
Building Materials, 26, 532-540.
Mihashi, H., Kaneko, Y., Nishiwaki, T., Otsuka, K., 2000. Fundamental study on
development of intelligent concrete characterized by self-healing capability forstrength, Transactions of the Japan Concrete Institute, 22, 441-450.
Kessler, M.R., Sottos, N.R., White, S.R., 2003. Self-healing structural composite
material, Composites: Part A 34, 743-753.
Joseph, C., Lark, R., Jefferson, T., Gardner, D., 2009. Potential application ofself-healing materials in the construction industry, A report for the Institution of
Civil Engineerers, Cardiff university.

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Response characteristics of R/C buildings
considering impulsive forceof tsunami drifting objects
Ho CHOI1, Kazuto MATSUKAWA2 and Yoshiaki NAKANO3
1
Research Associate, Institute of Industrial Science, The University of Tokyo, Japan
choiho@iis.u-tokyo.ac.jp
2
Research Associate, Institute of Industrial Science, The University of Tokyo, Japan
3
Professor, Institute of Industrial Science, The University of Tokyo, Japan
ABSTRACT
After the 2011 Great East Japan Earthquake, the quantitative evaluation methodof tsunami load and the design guideline for tsunami evacuation buildings were
established in Japan. However, the impulsive force of drifting objects such as
vessels and containers etc. due to tsunami is not taken into consideration in theguideline. Therefore, it is necessary to establish the quantitative evaluation
method of the impulsive force and to investigate whether the force should be taken
into account to the current design guideline for tsunami evacuation buildings.
In this paper, the response characteristics of R/C buildings considering theimpulsive force of tsunami drifting objects are analytically and experimentallyinvestigated. For this purpose, nonlinear analyses are conducted to evaluate thedynamic response of a six story R/C tsunami evacuation building, and collisionexperiments using 1/100 scale specimens are carried out to verify the validity ofanalytical results.
Keywords: the 2011 Great East Japan Earthquake, tsunami evacuation building,
impulsive force, drifting object, response characteristics
1. INTRODUCTION
The 2011 Great East Japan Earthquake that occurred at 14:46 local time on March
11, 2011, had magnitude of 9.0 on the Richter Scale with the epicenter
approximately 70 km east of the Oshika Peninsula in Miyagi Prefecture(38.322°N, 142.369°E, Depth: 32km). This earthquake triggered terrible tsunami
waves which hit the coast of Japan and propagated around the Pacific Ocean, andthis tsunami caused extensive and severe building damage such as pancake
collapse, overturning, movement, tilting, sliding, and debris collision. Authors
conducted tsunami damage investigations in Tohoku area (from Hachinohe city in
Aomori Prefecture to Soma city in Fukushima Prefecture) from the beginning ofApril through the end of June, 2011.

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After the 2011 Great East Japan Earthquake, the quantitative evaluation method oftsunami load and the design guideline for tsunami evacuation buildings were
established in Japan. However, the impulsive force of drifting objects such as
vessels and containers etc. due to tsunami as shown in Photo 1 is not taken into
consideration in the guideline. Therefore, it is necessary to establish thequantitative evaluation method of the impulsive force and to investigate whether
the force should be taken into account to the current design guideline for tsunami
evacuation buildings.
In this paper, the response characteristics of R/C buildings considering theimpulsive force of tsunami drifting objects are analytically and experimentallyinvestigated. For this purpose, nonlinear analyses are conducted to evaluate thedynamic response of a six story R/C tsunami evacuation building, and collisionexperiments using 1/100 scale specimens are carried out to verify the validity ofanalytical results.

(a) Collapsed building due to collision(b) Large vessel drifted by tsunami

Photo 1: Building damage due to collision of tsunami drifting object
2. BUILDING RESPONSE EVALUATION BY NONLINEAR ANALYSIS
2.1 Reference building and modeling for nonlinear response analysis
In this study, a six story apartment R/C building, which is a tsunami evacuationbuilding designed as tsunami inundation depth h=10m and water depth coefficient
a=2.0 (NILIM, 2012) as shown in Figure 1, is selected to analytically evaluate theresponse characteristics due to both of the tsunami load and the impulsive force ofa tsunami drifting object.
The assumptions on nonlinear response analyses are as follows.
(1) The reference building is replaced as six degree of freedom model with single
degree of freedom per one story as shown in Figure 2.
(2) The base shear coefficient C of this building is 1.15.
(3) The hysteretic characteristic of each story is employed Takeda model (Takeda,
T. et al., 1970) having yielding drift angle of 1/200 rad. and stiffness
degradation factor � of 0.4 after yielding point.

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13,500(4) The well-known Newmark � method is employed for numerical integration.
(5) The predominant period of this building is set as 0.26 second, and the weight
per unit floor area is assumed as 14 N/mm2.

(a) Floor plan of first floor(b) Elevation of sea side
Figure 1: Reference building
2.2 Estimation of tsunami load and impulsive force
As shown in Figure 2, overall tsunami load acting on the reference building isassumed a triangular shape with the height reaching the water depth coefficient atimes of the design tsunami inundation depth h based on the Japanese guideline(NILIM, 2012), and the tsunami load acting on each floor is calculated by halvesof story height of up-and-down story.
The debris collision force shown in Figure 2 is calculated by Mizutani equation
shown in equation (1) (Mizutani, N. et al., 2007), and then the impulsive force canbe computed by the product of the collision force Fm and the collision time dt.

Fm  2 BcVx2 

WVx
gd t

a  2 Fr
V
Fr 
gh

(1)

(2)
(3)

where,
Fm : Debris collision force (kN)
� : Mass per unit volume of water (1.0 t/m3)

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herein)Bc : Width of tsunami drifting object (m)Vx : Collision velocity (6.6 m/s, assumed as a half of tsunami flow velocity V(13.2 m/s) mentioned later)
W : Weight of tsunami drifting object (kN)g : Gravity acceleration (9.8 m/s2)
dt : Collision time (s, assumed 10ms to 50ms (Mizutani, N. et al., 2007))
a : Water depth coefficient (=2.0 herein)
Fr : Froude number
V : Tsunami flow velocity (13.2 m/s, calculated by equation (2) and (3))

Figure 2: Schematic illustrations of tsunami load and impulsive force
2.3 Analysis parameters

Table 1 shows the parameters of this analysis. As shown in the Table, main
parameter of Case 1 is the debris mass, and that of Case 2 is the collision time,
respectively.
Table 1: Parameters of this analysis

Case 1Case 2816

Debris mass (t)
100
200
300
400

200

Collision time (s)Collision velocity (m/s)

30

6.6

10
30
50

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2.4 Analysis results
2.4.1 Results of Case 1
Figure 3 shows the distribution of the ductility factor of each story according toincreasing the mass of tsunami drifting objects. When only tsunami load isconsidered, the ductility factors of all stories are less than 1.0 of ductility factor.
However, as the debris mass increases, the ductility factors of each story also
increase, and yielding point is exceeded in more than 200t of the debris mass. This
result means that it is occasionally necessary to take into account the influence ofthe collision of tsunami drifting objects at the time of the structural design of atsunami evacuation building.
6

Only tsunami loadDebris mass (100t)
Debris mass (200t)
Debris mass (300t)
Debris mass (400t)

5

Story

4
3

Collision point

2
1
0
0.0

Cracking
point
0.5

Yielding point
1.0
1.5
Ductility factor

2.0

2.5

Figure 3: Ductility factor of each story according to increasing of debris mass
2.4.2 Results of Case 2
Figure 4 shows the distribution of the ductility factor of each story in accordancewith changing the collision time. As shown in the figure, even if the collision time
is changed, maximum ductility factors are almost the same. This result is caused
by equation (1) employed in this analysis. Since the equation governs the second
term, it can be briefly rewritten as equation (4). If the products of the debris mass
m and the collision velocity Vx (i.e., the momentum) are the same as this case, the6

Only tsunami load
Collision time (10ms)
Collision time (30ms)
Collision time (50ms)

5

Story

4

Collision point

3
2
1
0
0.0

Cracking
point

Yielding point
0.5
1.0
Ductility factor

1.5

Figure 4: Ductility factor of each story according to changing collision time
Response characteristics
of R/C buildings
considering
impulsive
force oftsunamidrifting
objects
Response characteristics
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considering
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drifting
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October
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Vietnamcollision time dt and the collision force Fm serve as reciprocal relations as shownin equation (4). Therefore, the impulsive forces calculated by the product of thecollision force and the collision time become the same, and eventually maximum
ductility factors also become the same.
Fm d t  mVx(4)

3. COLLISION EXPERIMENT USING SCALED MODEL
3.1 Outline of experiment and measurement system

In this study, 1/100-scale specimens which are model building designed by thereference building shown in Figure 1 and model tsunami drifting objects
supposing vessels of 100 to 300 ton class are fabricated, and the collision tests arecarried out to investigate the collision force and the collision time between modelbuilding and model tsunami drifting object. Figure 5 shows the schematic
illustration of this experiment system. As shown in the figure, the model building
fixed to linear slider run onto the model tsunami drifting object in this test.

Figure 5: Schematic illustration of this experiment system
The maximum collision force Fm and the collision time dt are calculated from thewave pattern obtained by the load cell installed the model building as shown in
Figure 5. The relative lateral displacement of the model building is measured by
the laser displacement sensor.
3.2 Experiment parameters

Table 2 shows the parameters of this experiment. As shown in the Table, main
parameter of Case 1 is the debris mass, and that of Case 2 is the same momentum
which is calculated by the product of the collision velocity and the debris mass,
respectively.

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Table 2: Experiment parameters
Collision velocity(mm/s)

Case 1200

Case 2

300
150
100

Debris mass (g)
100
200
300
100
200
300

Plate thickness (mm)

0.5
0.5

3.3 Experiment results
3.3.1 Results of Case 1
Figures 6(a) and 6(b) show the relationships between the collision force and thecollision time, and the maximum collision displacement and the impulse force due
to different mass of tsunami drifting object, respectively. As can be found in

Collision force (N)50 [Case 1]
40[Mass of tsunami drifting object]
100g
200g
300g

30
20
10
0
0.995

1.000

Time (sec.)

1.005

1.010

Max. collision displacement (mm)(a) Relation of collision force and collision time due to mass of drifting object
0.05[Case 1]

0.04
0.03
0.02
0.01
0.00
0.00

[Mass of tsunami drifting object]
100g
200g
300g
0.05
0.10
Impulsive force (N*s)0.15(b) Relation of collision displacement and impulsive force due to mass of drifting object
Figure 6: Results of Case 1
Response characteristics
of R/C buildings
considering
impulsive
force oftsunamidrifting
objects
Response characteristics
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considering
impulsiveforce
of tsunami
drifting
objects819

October
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VietnamFigure 6(a), both of the collision force and the collision time quantitatively
increase as the debris mass increases. Furthermore, the maximum collisiondisplacement and impulsive force increase linearly together with increasing debris
masses as shown in figure 6(b).
3.3.2 Results of Case 2
Figures 7(a) and 7(b) show the relations of the collision force and the collisiontime, and the maximum collision displacement and the impulsive force undersame momentum, respectively. As the debris mass increases and the collisionvelocity decreases, the collision time increases and the collision force decreases asshown in Figure 7(a). However, the impulsive force and the collisiondisplacement are almost the same under same momentum as shown in Figure 7(b).

Collision force (N)40 [Case 2][Same momentum]
100g 300mm/s
200g 150mm/s
300g 100mm/s

30
20
10
0
0.995

1.000

Time (sec.)

1.005

1.010

Max. collision displacement (mm)(a) Relation of collision force and collision time under same momentum
0.05[Case 2]

0.04
0.03
0.02
0.01
0.00
0.00

[Same momentum]
100g 300mm/s
200g 150mm/s
300g 100mm/s
0.05
0.10
Impulsive force (N*s)0.15(b) Relation of collision displacement and impulsive force under same momentum
Figure 7: Results of Case 2
3.3.3 Relationship between impulsive force and momentum
In this section, the relationship between the momentum of the model tsunami
drifting object and the impulsive force imposed the model building is investigated.

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As shown in Figure 8, the impulsive forces calculated by the product of thecollision force Fm and the collision time dt shown in equation (4) are about 2 timesof the momentums obtained by the product of the debris mass m and the collisionvelocity Vx. This result is different from the analysis result that the impulsive force
is almost equal to the momentum as shown in equation (4) and Figure 4 in section
2.4.2. This can be explained from equation (7) obtained by equations (5) and (6)based on the law of conservation of momentum and the law of conservation ofenergy, respectively. As shown in equation (7), the velocity vx’ of tsunami drifting
object after the collision is 2 times of the velocity Vx of building before thecollision when the value of � is close to zero (M»m), while vx’ is almost equal toVx when � is 1.0 (M=m). In this test, since the mass of the building is quite larger
than that of tsunami drifting object, the impulsive force became twice themomentum as mentioned above.

Impulsive force by experiment (kg*m/s)

0.14
0.12

2.0
1.0

0.10
0.08
0.06
0.04
0.02
0.00
0.00

Case1
Case2
0.02 0.04 0.06 0.08 0.10 0.12
Momentum by experiment (kg*m/s)

0.14

Figure 8: Relation of impulse force and momentum by experimentMVx  mv x  MVx '  mvx '
2
2
1
1
1
1
MVx 2  mv x 2  M Vx '  m v x '
2
2
2
2
2
m

'
vx 
Vx    
M
1


 

 

(5)
(6)

(7)

where,
M, m : Mass of building and tsunami drifting object, respectively: Velocity of building and tsunami drifting object before collision,Vx, vxrespectively (v is zero in this test)
Vx’, vx’ : Velocity of building and tsunami drifting object after collision,respectively
� : Ratio of mass of tsunami drifting object to mass of building

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4. CONCLUSIONSIn order to investigate the response characteristics of R/C buildings due tocollision force of tsunami drifting objects, nonlinear response analyses and simple
collision tests are carried out. The major findings can be summarized as follows.
(1) As increasing of the mass of tsunami drifting object, both of the impulsive
force and the maximum displacement of the building increased in both of theanalyses and the tests.
(2) When the amount of the momentum is constant, the impulsive force and the
maximum displacement of the building are constant in both of the analyses
and the tests.
(3) When the mass of the building is quite larger than that of tsunami drifting
object, the impulsive force became twice the momentum.
In future research, the collision tests for the value of � which is the ratio between
masses of building and tsunami drifting object will be carried out to establish thedesign procedure of a tsunami evacuation building considering the collision force.
REFERENCES

National Institute for Land and Infrastructure Management (NILIM), 2012.
Practical Guide on Requirement for Structural Design of Tsunami Evacuation
Buildings. Technical note of NILIM, No.673. (in Japanese)
Takeda, T., Sozen, A., and Nielsen, N.M., 1970. Reinforced Concrete Response to
Simulated Earthquakes. Journal of Structural Division, ASCE, Vol.96:No.ST12,
2557-2573.
Yeom, G.S., Muzutani, N., Shiraishi, K., Usami, A., Miyajima, S., and Tomita, T.,2007. Study on Behavior of Drifting Containers due to Tsunami and Collision
Forces. Journal of Japan Society of Civil Engineers, Ser.B2 (Costal Engineering),
JSCE, Vol.54, 851-855.

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NIOM analysis of vertical array records
observed in RC structure buildings
Yusuke ODA1, Hidenori MOGI2 and Hideji KAWAKAMI3
1
Student, Saitama University, Japan
2
Assoc. Professor, Civil & Environmental Engineering, Saitama University, Japan
3
Professor, Geosphere Research Institute, Saitama University, Japan
ABSTRACTIn this research we conducted normalized input–output minimization (NIOM)
analysis to investigate the S-wave velocities propagating on the two different RC
buildings in Japan: (1) the 6th building of the Kashiwazaki-Kariwa Nuclear Power
Plant in Niigata Prefecture, and (2) the Nagata high-rise building in Hyogo
Prefecture. The 6th building of Kashiwazaki-Kariwa NPP sustained no damaged
from the 2007 Chuetsu-oki earthquake while the Nagata high-rise building wasreportedly damaged by the 1995 Hyogoken-Nanbu earthquake. The results of therecords for the 6th building in the Kashiwazaki-Kariwa NPP before and after the2007 earthquake shows no clear changes in the S-wave velocity that ranges from
800 m/s to 1100 m/s. Based on this, we concluded that there was no structural
damage to the building caused by the strong ground motions. On the other hand,
the results from the Nagata high-rise building show an abrupt decrease of the Swave velocity from 200 m/s to 100 m/s for the B1F to 5F, and 150 m/s to 100 m/s
for the 5F to 24F during the main shock of the 1995 earthquake. These results are
consistent with the reported extent of damages to the building.
Keywords: NIOM analysis, S-wave velocity, vertical array records, earthquake
damage of RC building
1. INTRODUCTION
The Niigata-ken Chuetsu-oki earthquake (16 July 2007, M 6.8) caused severe
structural damage in Niigata Prefecture. Damage was also observed in the Tokyo
Electric Power Company’s (TEPCO) Kashiwazaki-Kariwa Nuclear Power Plant(NPP) located about 8.5 km from the fault rupture (TEPCO, 2008). And also the
Hyogoken-Nanbu earthquake (17 January 1995, M 7.3) caused severe damage in
Hyogo Prefecture. Damage was also observed in the Nagata high-rise building(Hayashi et al., 1997).
Kawakami and Haddadi (1998) developed normalized input–output minimization(NIOM) method to examine wave propagation velocity using vertical arrayrecords. In this study, using the NIOM method, we investigate the S-wave
velocity in the two different RC building. With the consideration for structural
damages in the buildings, we examine the validity of NIOM method.

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2. Outline of the NIOM Method
This section describes the outline of NIOM method developed by Kawakami and
Haddadi (1998). Let �(�) be the transfer function of a system representing therelationship between two points in a vertical array where the waveforms areobserved simultaneously. Then the output model of the system, y(t) , for an
arbitrary (real-valued) input model x(t) can be calculated by(1)

Y(ω) = H(ω)X(ω)

where X(ω) and Y(ω) are the Fourier transforms of the input and output models
x(t) and y(t), respectively. To get the simplified input and output models thatsatisfy equation (1), the following constraint is imposed on input x(t):x(0) =

�

N∆�

∑N��
��� X(ω� )�x� ������N� |��� =

�

N∆�

∑N��
��� x(ω� ) = 1(2)

And the sum of the squared Fourier amplitude and its time derivatives areminimized subjected to the previously described constraint. Thus, the Lagrange
multiplier method gives
�
�
�
�
�
�
L = ∑N����� �|X(ω� )| + kω� |X(ω� )| + |Y(ω� )| + kω� |Y(ω� )| � −�λ � ∑N����� X(ω� ) − 1�
N��

(3)

where λ is the Lagrange multiplier, and k is the weighting constant for the time
derivatives. Substituting equation (1) into equation (3) and minimizing theresulting equation yields,
��
��

=

��

��(�� )=

����∗ (�� )= 0���� = 0� � � � � ���(4)

Where ∗ denotes the complex conjugate. After minimization, the input modelX(ω� ) and output model Y(ω� ) are obtained as follows:X(ω� ) = N∆t���(���H��������� �� )
�
�
∑���
�
���
������� �(���H��� �� )Y(ω� ) = H(ω� )X(ω� )

(5)
(5)

The parameter k in equation (3) controls the contribution of high frequency
components to L. That is, increasing the value of k decreases the contribution ofhigh-frequency components. However, as the time lag time that results into aprominent peak in the output model is not affected much, the choice of the valueof k is not so critical.

Lastly, the inverse Fourier transforms of the input model X(ω) and output modelY(ω) will give the simplified input model x(t) and y(t), in time domains. For the
calculation of the inverse Fourier transform using fast Fourier transforms (FFT),824

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the first half of the Fourier components of the models is calculated by equation (5),and the number of the Fourier components is increased by a factor of 16 by
padding with trailing zeros to interpolate time intervals by 1/16. Then, the latter
half of the Fourier components is set to the complex conjugates of the first half to
get real-valued waveforms by FFT. As mentioned previously, the NIOM method
is a simple input–output analysis technique in which the transfer function is
calculated from two observations satisfying input x(t) at x(0) = 1. It is similar to areceiver function (Langston, 1989). In a receiver function, input x(t) should beassumed as a suitable pulse; however, in the NIOM method, the adjustment
features are included to get simplified input and output waveforms.
3. The 6th building of the Kashiwazaki-Kariwa Nuclear Power Plant
Figure 1 shows the cross-sectional view of the 6th building of the KashiwazakiKariwa Nuclear Power Plant and the location of seismometers. For this study,
records from seismometers R66 and R67 are used (marked with circle in Figure 1).
These two seismometers were equipped with three sensors in EW, NS and UD
directions, respectively. The distance between seismometers R66 and R67 is 39.9m.

Figure 1: Cross-sectional view of the 6th building of the Kashiwazaki-Kariwa
Nuclear Power Plant.
In NIOM analysis for the earthquakes that occurred before and after the Niigataken Chuetsu-oki earthquake, 10 sec time intervals of the principal motion in the Swave part were analyzed. Figure 2(a) shows an example of observed waveformand Figure 2(b) shows the result of NIOM analysis. The earthquake
accelerograms analyzed in this article are summarized in Table 1. Among theseearthquakes, a through l1 (see Table 1) are aftershocks of the 2007 Niigata-ken
Chuetsu-oki earthquake. Similarly, A to J are earthquakes that occurred before theNiigata-ken Chuetsu-oki earthquake and MS indicates mainshock of the Chuestuoki earthquake. Mainshock of the Chuestu-oki earthquake records was notrecorded at R66 and R67 seismometers. So we conducted NIOM analysis of theearthquakes that occurred before the Niigata-ken Chuetsu-oki earthquake and

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October
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Vietnamaftershocks of the 2007 Niigata-ken Chuetsu-oki earthquake. The earthquakes that
occurred before the Niigata-ken Chuetsu-oki earthquake included that of occurredat Niigata and the rest off the coast of Noto penibshula. The epicenter location isshown in Figure 3.

(a) Observed waveforms of aftershock of the Chuestu-oki earthquake on 16 July
2007 at 11:00, M3.7.

(b) Results of the NIOM analysis for the waveforms
Figure 2: Example waveforms and NIOM results

Figure 3: Location of epicenter for the NIOM analysis at the Kashiwazaki-Kariwa
Nuclear Power Plant

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Table 1: Source parameters of the earthquakes analyzed in this study
Date,time (JST)Longitude

Latitude

Depth
(km)

2006/03/07 12:46
2006/03/14 12:01
2006/04/01 06:22
2006/12/26 05:17
2007/01/08 18:59
2007/03/25 09:41
2007/03/25 18:11
2007/03/26 14:46
2007/06/11 03:45
2007/06/22 03:34
2007/07/16 10:13
2007/07/16 11:00
2007/07/16 11:01
2007/07/16 11:05
2007/07/16 11:12
2007/07/16 11:15
2007/07/16 11:20
2007/07/16 11:24
2007/07/16 11:25
2007/07/16 11:30
2007/07/16 11:35
2007/07/16 11:37
2007/07/16 11:43
2007/07/16 11:47
2007/07/16 11:50
2007/07/16 11:53
2007/07/16 11:56
2007/07/16 12:01
2007/07/16 12:04
2007/07/16 12:11
2007/07/16 12:20
2007/07/16 12:27
2007/07/16 12:29
2007/07/16 12:34
2007/07/16 12:37
2007/07/16 12:49
2007/07/16 12:59
2007/07/16 13:09
2007/07/18 11:47
2007/07/18 16:53
2007/07/20 01:52
2007/07/25 06:52
2007/12/20 15:17
2008/03/07 07:11
2008/03/12 17:59
2008/03/18 04:40
2008/03/21 15:40
2008/03/25 10:54
2008/03/29 19:29

138 ﾟ 59.9 '138 ﾟ 10.4 '138 ﾟ 26.0 '138 ﾟ 09.6 '138 ﾟ 55.2 '136 ﾟ 41.2 '136 ﾟ 50.4 '136 ﾟ 33.1
136 ﾟ 39.2 '136 ﾟ 40.0 '136 ﾟ 60.8 '138 ﾟ 33.9 '138 ﾟ 37.3 '138 ﾟ 29.1 '138 ﾟ 28.2 '138 ﾟ 33.0 '138 ﾟ 34.3 '138 ﾟ 27.8 '138 ﾟ 35.4
138 ﾟ 33.3 '138 ﾟ 34.8 '138 ﾟ 33.7 '138 ﾟ 37.6 '138 ﾟ 32.0 '138 ﾟ 34.7 '138 ﾟ 35.5 '138 ﾟ 35.2 '138 ﾟ 35.3 '138 ﾟ 31.8 '138 ﾟ 33.0 '138 ﾟ 32.7 '138 ﾟ 34.9 '138 ﾟ 33.7 '138 ﾟ 32.5 '138 ﾟ 34.3 '138 ﾟ 31.8 '138 ﾟ 29.9 '138 ﾟ 33.5 '138 ﾟ 34.1 '138 ﾟ 36.9 '138 ﾟ 33.4 '138 ﾟ 43.2 '138 ﾟ 35.5 '138 ﾟ 34.1 '138 ﾟ 34.1 '138 ﾟ 38.0 '138 ﾟ 31.7 '138 ﾟ 33.8 '138 ﾟ 32.6 '37 ﾟ 20.3 '37 ﾟ 30.1 '37 ﾟ 07.7 '37 ﾟ 52.4 '37 ﾟ 16.0 '37 ﾟ 13.2 '37 ﾟ 18.3 '37 ﾟ 09.9 '37 ﾟ 14.6 '37 ﾟ 55.7 '37 ﾟ 52.6 '37 ﾟ 27.4 '37 ﾟ 35.0 '37 ﾟ 29.8 '37 ﾟ 27.1 '37 ﾟ 26.9 '37 ﾟ 30.1 '37 ﾟ 25.7 '37 ﾟ 29.8 '37 ﾟ 24.9 '37 ﾟ 29.7 '37 ﾟ 29.6 '37 ﾟ 22.8 '37 ﾟ 24.9 '37 ﾟ 28.4 '37 ﾟ 29.7 '37 ﾟ 29.8 '37 ﾟ 29.7 '37 ﾟ 29.6 '37 ﾟ 30.4 '37 ﾟ 30.7 '37 ﾟ 28.1 '37 ﾟ 32.0 '37 ﾟ 32.9 '37 ﾟ 30.2 '37 ﾟ 29.4 '37 ﾟ 28.8 '37 ﾟ 30.2 '37 ﾟ 28.6 '37 ﾟ 26.5 '37 ﾟ 27.1 '37 ﾟ 31.9 '37 ﾟ 35.3 '37 ﾟ 26.9 '37 ﾟ 26.8 '37 ﾟ 30.2 '37 ﾟ 29.3 '37 ﾟ 27.0 '37 ﾟ 30.8 '

7.76
274
19.7
14.46
13.34
10.7
13.45
8.62
7
8
17
22
20
23
24
17
20
18
20
19
12
22
26
18
19
16
17
19
21
19
20
22
17
18
18
19
20
18
18
23
19
24
16
18
20
15
17
20
20

Epicenterdistance
(km)
36
39
35
64
33
171
156
184
174
182
16
5
19
14
12
6
10
12
9
4
9
9
5
6
7
9
9
9
11
11
12
6
13
15
10
10
11
10
7
3
5
17
19
4
4
10
10
5
12

Symbols forearthquake

NIOM analysis
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records
observedin RC
structurebuildings
NIOM
analysisarrayof vertical
array
records
observedin RC
structure buildings

A
B
C
D
E
F
G
H
I
J
MS
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
a1
b1
c1
d1
e1
f1
g1
h1
i1
j1
k1
l1

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October
2013, 2013,
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Vietnam0ctober
VietnamFigure 4 shows temporal changes of the S-wave velocities between the R66 andR67 seismometers. Before and after the mainshock of the Chuetsu-oki earthquake,small changes in propagation velocity can be seen. Then we considered the shear
modulus, given by
μ = Vs� ∗ ρ ,(6)where, μ is the shear modulus, Vs is the S-wave velocity and ρ is the density.
There is no changes in the shear modulus caused by the Chuets-oki earthquake of
the Kashiwazaki-Kariwa Nuclear Power Plant’s 6th building. This suggests that
there was no damage of the building caused by the Chuetsu-oki earthquake. In thisstudy, however, we obtained small changes in the value; not caused by the strong
ground motion. Comparison of S-wave velocities for each components show that
the NS component is larger than the EW component.

Aftershocks of the Chuetsu-oki earthquake

Before the Chuetsu-oki earthquake

S-wave velocity (m/s)

1500

1500

1000

1000

500

500

EW ●
NS △

0

A B C D E F G H I

J

0

0.1

1

10

100

Days after the Chuetsu-oki Earthquake

Figure 4: Temporal changes in the S-wave velocity between R66 to R67
seismometers at the Kashiwazaki-Kariwa Nuclear Power Plant 6th building
estimated from the earthquake records before and after the Chuetsu-oki
earthquake.
4 Nagata high-rise building
Figure 5 is the cross-sectional view of the Nagata high-rise building. As in thecase of the Kashiwazaki-Kariwa Nuclear Power Plant’s 6th building, seismometers
recorded three components, i.e., EW, NS, and UD directions,. In this study, we
use the seismometers located at 24F, 5F, and B1F. The distance between 24F and
5F is 54.4 m, while the distance between 5F and B1F is 24 m.
In NIOM analysis for the Hyogoken-nanbu earthquake, a moving window of 4.0-

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sec duration was used from 4 to 37 sec at an increment of 1 sec. The epicenter andNagata high-rise building location are shown in Figure 6. Figure 7(a) shows theobserved waveforms of the Hyogoken-nanbu earthquake while (b) shows theresult of NIOM analysis.

Figure 5: Cross-sectional view of the Nagata high-rise building (Hayashi et al.,1997)

Figure 6: The epicenter of the 1995 Hyogoken-nanbu earthquake and the locationof Nagata high-rise building

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Vietnam(a) Observed waveforms of Hyogoken-nanbu earthquake on 17 January 1995 at
05:46 (AIJ, 1996)

NS

EW(b) Results of the NIOM analysis for the waveforms
Figure 7: Results for the Hyogoken-Nanbu earthquake record
Figure 8 shows the temporal changes in the S-wave velocities at the Nagata highrise building estimated from the records of the Hyogoken-nanbu earthquake.
Between the 5F and B1F, abrupt decrease in the S-wave velocities from 200 m/s
to 100 m/s is seen. On the other hand, between the 24F and 5F, decrease in the Swave velocities from 150 m/s to 100 m/s are observed. Decline of propagation
speed is clearly seen in the lower part of the building than on the upper part of thebuilding. This suggests that the damage of the lower part of the building waslarger than the upper part of the building. In fact almost all the beams had shear
failure near the opening of doorway and large shear cracks occurred in the walls(Hayashi et al., 1997). Comparison between this result and that of the Chuetsu-oki
earthquake, decrease in the S-wave velocities was clearly observed for Nagata
high-rise building.

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S-wave velocity (m/s)

ICUS Report 73

Mainshock of the Hyuogoken-nanbu earthquake between 5F and 24F
500
EW ▲
400
NS △
300
200
100
0

5

10
15
20
25
30
center of the time window considered (sec)35

S-wave velocity (m/s)

Mainshock of the Hyogoken-nanbu earthquake between B1F and 5F
400

EW ●
NS ○

300
200
100
0

5

10
15
20
25
30
center of the time window considered (sec)35

Figure 8: Temporal change of the S-wave velocities at Nagata high-rise building.
5 Conclusions
1.

2.

3.
4.
5.

The S-wave velocities before and after the Chuestu-oki earthquake for the
Kashiwazaki-Kariwa nuclear power plant’s 6th building was almost the same.
However, when the S-wave velocity of each component is compared, the NScomponent is larger than the EW component. S-wave velocity of the NScomponent is about 1100 m/s, while the EW component is about 800 m/s.
Decrease in the S-wave velocities during the mainshock of the Hyogokennanbu earthquake for 5F to B1F was observed. The S-wave velocities of the
NS component fell from 200 m/s to 100 m/s. On the other hand, the S-wave
velocities of the EW component fell from 300 m/s to 100 m/s.
A slight decrease in the S-wave velocities during the mainshock of the
Hyogoken-nanbu earthquake for 24F to 5F was observed.
Based on conclusions 2 and 3, there is a clear indication that structural
damage occurred in the Nagata high-rise building. And it is thought that thelower part of the building had serious damage.
Based on S-wave velocities estimated by the NIOM method, we confirmedthat the 6th building of the Kashiwazaki-Kariwa Nuclear Power Plant suffered
no damage.

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REFERENCES
Mogi, H., Shrestha, S. M., Kawakami, H. and Okamura, S., 2010. Nonlinear Soil
Behavior Observed at Vertical Array in the Kashiwazaki-Kariwa Nuclear Power
Plant during the 2007 Niigata-ken Chuetsu-oki Earthquake. Bulletin of the
Seismological Society of America, Vol. 100, No. 2, 762-775 (DOI:
10.1785/0120090091)
Hayashi, Y., Yasui, Y. and Yoshida, N., 1997. Effects of Soil-StructureInteraction in Heavily Damaged Zone during Hyogo-ken Nanbu Earthquake. 7th
Dynamic interaction symposium of a structure and foundation: The aseismic
designing method which considered the dynamic interaction, Architectural
Institute of Japan, 12-24.
Kawakami, H., and H. R. Haddadi., 1998. Modeling wave propagation by using
normalized input–output minimization (NIOM), Soil Dynamics and Earthquake
Engineering. Vol. 17, 117–126.
TEPCO, 2008. Accelerograms observed at the Kashiwazaki-Kariwa Nuclear
Power Plant (revised version), DVD-ROM.
Architectural Institute of Japan (AIJ), 1996. Strong motion records observed
during the 1995 Hyogoken-Nanbu earthquake (in Japanese).
Langston, C. A., 1979. Structure under Mount Rainier, Washington, inferred fromteleseismic body waves, Journal of Geophysical Research 84, No. B9, 4749–4762.

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Residual seismic capacity evaluationof RC frame with weak-beams
based on energy absorption capacity
Chunri QUAN1, Ho CHOI2, Noriyuki TAKAHASHI3, Yoshiaki NAKANO4
and Kazuto MATSUKAWA2
1
Graduate Student, Graduate School of Engineering, The University of Tokyo, Japanquancr@iis.u-tokyo.ac.jp
2
Research Associate, Institute of Industrial Science, The University of Tokyo, Japan
3
Associate Professor, Faculty of Engineering, Tohoku University, Japan
4
Professor, Institute of Industrial Science, The University of Tokyo, Japan
ABSTRACTThe objective of this study is to develop a method to evaluate residual seismic
capacity of damaged RC frames with weak-beams after earthquakes. For thispurpose, the residual seismic capacity ratio, which is defined as the ratio of
residual energy absorption capacity to the initial (pre-earthquake) energy
absorption capacity of an overall frame, is proposed for the weak-beam RC
frames (detailed calculation method). Furthermore, a simplified calculation
method for residual seismic capacity ratio is developed employing visual damage
information such as maximum residual crack width of members.
In this paper, two evaluation methods, i.e. detailed and simplified methods, forresidual seismic capacity of weak-beam RC frames mentioned above are applied
to two test results. The relationships between the residual seismic capacity ratio
and damage ratings such as slight, light, moderate, heavy and collapse are
discussed and then the validity is confirmed based on the detailed calculation
method. It is also revealed that the simplified calculation method can successfully
evaluate the residual seismic capacity of weak-beam RC frames from the visualdamage information based on the comparison results of detailed and simplified
calculation methods.
Keywords: residual seismic capacity evaluation, weak-beam RC frames, energy
absorption capacity, residual seismic capacity ratio, damage rating
1. INTRODUCTION
The major concern for damaged buildings after an earthquake is their safety to theaftershocks, and also quick damage inspections are needed. In the next stage
following the quick damage inspections, a damage evaluation should be more
precisely and quantitatively performed, to identify necessary actions required forthe damaged buildings. For this purpose, the Guidelines for Post-Earthquake
Damage Evaluation and Rehabilitation (JBDPA, 2001) originally developed in1991 was revised in 2001 in Japan. In the guidelines, the damage classes ofstructural members should be classified first from the damage state. Then, a833

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamseismic capacity reduction factor η which is defined as the ratio of the absorbablehysteretic energy after an earthquake to the original absorbable energy of eachstructural member should be calculated corresponding to the damage classes ofmembers. Considering the seismic capacity reduction factor η, a residual seismic
capacity ratio index R which is defined as the ratio of post-earthquake seismic
capacity to original capacity can be calculated. Finally, the damage of a building
can be rated based on the damage rating criteria.
However, the current Japanese guidelines mentioned above mainly consider
vertical members such as columns and walls. Since RC buildings with weakbeams are generally designed and constructed in recent years, the guidelines areoften difficult to apply to those buildings. Accordingly, in this paper, a detailed
calculation method of residual seismic capacity ratio index SImargin is proposed forthe weak-beam RC frames. Then, a simplified calculation method for the index
SImargin is developed employing visual damage information such as the maximum
residual crack width of each structural member. Furthermore, the detailed andsimplified methods proposed to calculate the index SImargin are applied to two
weak-beam RC specimens, and the relationships between the index SImargin anddamage rating are discussed and their validity is verified based on the detailed
calculation method. The validity of the simplified calculation method is also
confirmed based on the comparison results of the detailed and simplified
calculation methods.
2. RESIDUAL SEISMIC CAPACITY EVALUATION METHOD
2.1 Detailed calculation method of index SImargin
The basic concept of residual seismic capacity evaluation method for the weakbeam RC frames is illustrated in Figure 1.
Energy Absorption Capacityof Overall Frame
Load

Dissipated & Absorbable
Energy of Member i

Safety Limitation of Frame
Mi

n

n

M-θ Relation of Member i
Safety Limitation
Dissipated Energy Ed,iof FrameE  M 
i 1

*
u ,i

i 1

*
u ,i u ,iResidual EnergyEr,i r ,i u*,i  i

Equation (1)Calculate the Residual Seismic Capacity Ratio Index SImargin
Damage Rating Criteria
Classify the Damage Rating of Frame

Figure 1: Basic concept of residual seismic capacity evaluation method

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In this paper, the seismic capacity of building structure is evaluated based on theenergy absorption capacity of overall frame considering the principle of virtual
work. The energy absorption capacity of overall frame can be calculated as thetotal absorbable energy of structural members until the safety limitation of a frame,
where this safety limitation is defined as the moment in which the maximum
lateral strength of a frame deteriorates to its 80%. Then, the residual seismic
capacity ratio index SImargin of overall frame is defined as the ratio of total residualenergy absorption capacity to the total initial energy absorption capacity ofstructural members as shown in Equation (1).
 n
SI m arg in    Er ,i i 1n E  100 %
i 1

*
u ,i

(1)

where, ∑E*u,i: total absorbable energy of structural members before earthquake,∑Er,i: total residual absorbable energy of structural members after earthquake
2.2 Definition of damage rating for weak-beam RC frames
In Japan, the damage ratings for weak-column RC buildings such as slight, light,
moderate, heavy and collapse are generally classified from the state of observed
damage of buildings as shown in Table 1 (AIJ, 1980).
Table 1: Definition of damage rating for weak-column RC buildings (AIJ, 1980)
Damage rating

Description of damage

SlightSlight or almost no damage on the columns
and walls.

Light

Slight damage on the columns and shear
walls, visible shear cracks on secondary
walls.

Moderate

Visible clear flexural and shear cracks oncolumns, visible shear cracks on shear
walls, remarkable heavy damage on
nonstructural members.

Heavy

Exposing and bucking of reinforcing bars
on columns, considerable lateral strength
deterioration of buildings with remarkablewide shear cracks on shear walls.

Collapse

Remarkable heavy damage on columns
and shear walls, overall or partial collapse
on buildings.

SketchResidualseismic
capacityofevaluation
RCweak-beams
frame with weak-beams based on energy
Residual seismic
capacity
evaluation
RC frame ofwithabsorption
capacity
based on energy absorption capacity835

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamHowever, such a damage rating is not clearly defined for weak-beam RC
buildings. Therefore, in this paper, the authors propose the criteria to define thedamage rating of weak-beam RC frames through the engineering demandparameter (EDP) as shown in Table 2 and Figure 2.
Table 2: Damage rating criteria for weak-beam RC Frames
Damage rating
No damageA

Initial cracking of member
Initial yielding of member

B

Formation of yield mechanismC

Maximum lateral strength of frame (Pmax)

D

80% of Pmax

E

Lateral Strength of Frame

Description of engineering demand parameter (EDP)

Pmax
Py
0.8Pmax
Py,1
Pc

A

B

C

・
・
③・
②
①
・
・
・
③
②
①

 c  y,1

D

E

Cracking member sequence
Yielding member sequence

y

 max

u

Displacement of Frame

Figure 2: Conceptual diagram of damage rating
2.3 Application to weak-beam RC specimens
To discuss the relationships between the index SImargin and damage ratings, in thissection, the detailed calculation method for the index SImargin is applied to thefollowing two weak-beam RC specimens as shown in Figure 3, which illustrates
the state of damage as well. 2SH-64 specimen is half-scale, two-bay, single-story
bare frame specimen (IIS & HAEI, 2011) with load cell for each corner column.
The lateral and vertical load carrying capacity of each column can be measured
from the two load cells, and the load-deflection curve of each beam also can beillustrated from the difference of vertical load between the two columns which areconnected with the end of the beam. 1SF specimen is full-scale, one by one-bay,single-story specimen, (BRI, 2011) with non-structural wall initially separated
from the inner surface of the structural members by slit with width of 25mm.
Since there is no load cell for this specimen, the lateral and vertical load carrying
capacity of each member can not be measured.

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Negative direction

Positive direction

Left Beam

Right Beam

Load Cell

Load Cell

Left Column

Center Column

Right Column(a) Damage state of the 2SH-64 specimen at 3.03% drift angle
Positive direction

Negative direction

Slit width: 25mm(b) Damage state of the 1SF specimen at 2% drift angle
Figure 3: Damage state of the two specimens

3

Load（×10 kN）

1.5

A B C

D

5.0

E

1.2

AB

D

C

4.0
0.8Pmax

0.9

3.0

0.6

2.0

0.3

1.0
(a)2SH-64 specimen

0
0

1

2

3

4

5

6

7

8

0.8Pmax900(b)1SF specimen

12

Drift angle (%)

3

4

5

6

7

8

9

Drift angle (%)

Dissipated Energy（kN・m）

Figure 4: Load-drift angle relations of the two specimens
100

A

B

600

D

C

80

D

C

400

60

300

40

200

20
0
0

A B

500

100

(a)2SH-64 specimen

1

2

3

Drift angle (%)

4

5

0
0

(b)1SF specimen

1

2

3

4

Drift angle (%)

5

6

Figure 5: Dissipated energy-drift angle relations of the two specimens
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2.3.1 Test results of two specimens
The load-drift angle relations of the two specimens are shown in Figure 4. Since
the connection between the spandrel wall and the center column of the 2SH-64
specimen was compromised, the center column is damaged as flexible member.
The load of the 1SF specimen was increased after the non-structural wall touched
to the columns at 2% drift angle.
The relationships between the dissipated energy, which is calculated from theload-drift angle skeleton curves of specimens, and the drift angle of the two
specimens are shown in Figure 5. The dissipated energy of the two specimens isincreased gradually at the damage ratings A and B, then the dissipated energy isinversely proportional to the drift angle at the damage ratings C and D.
2.3.2 Relationships between index SImargin and damage ratings
The index SImargin of the two specimens, which is calculated by the detailed
calculation method defined as Equation (1), is shown in Figure 6. The residual
and initial energy absorption capacity of 2SH-64 specimen is calculated as thetotal residual and initial energy absorption capacity of structural members such as
three columns and two beams. Since there is no load cell for 1SF specimen tomeasure the load carrying capacity of each member, the residual and initial energy
absorption capacity of 1SF specimen are calculated from its load-drift angle
skeleton curve. Then, the damage ratings of the two specimens are classified
based on Table 2, and illustrated in Figure 6 with the index SImargin.
The boundary values of the index SImargin to define damage rating criteria arecalculated for two specimens respectively from Figure 6, and shown in Table 3.
As a result, the boundary values of the index SImargin for the two specimens are
similar to each other for damage rating classification points, and it can beconsidered that the damage rating criteria is valid for those two specimens.
A

Index SImargin (%)

100

B

C

D

A

B

C

D

80
60
40
20
0
0

(a)2SH-64 specimen

12(b)1SF specimen

34

Drift angle (%)

5

0

1

2

3

4

5

Drift angle (%)

Figure 6: Index SImargin of two specimens based on detailed calculation method
Table 3: Damage rating criteria of two specimens
Specimen
2SH-64 specimen
1SF specimen

838

Boundary Value of index SImargin
A-B
B-C
C-D
96%
84%
63%
96%
90%
55%
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3. SIMPLIFIED CALCULATION METHOD OF INDEX SImargin
3.1 Flow of simplified calculation method
It is difficult to calculate the dissipated or absorbable energy of each structuralmember on-site. Therefore, in this chapter, a simplified calculation method for theindex SImargin is proposed considering factor η corresponding to visual damage
information such as maximum residual crack width of each structural member.
The basic concept of the simplified calculation method is shown in Figure 7.
Damage Classof Member

Seismic Capacity Reduction
Factor η of Member

Residual Seismic Capacity Ratio
Index SImargin of Building

Damage Ratingof Building

Classify the damage
classes of structuralmembers based on
the damage state.

Calculate the η corresponding
to the damage class of eachstructural member.

Calculate the index SImargin ofbuilding based on a weighted
average method (the simplified
calculation method).

Estimate the damageof building based on
the damage rating
criteria.

Figure 7: Basic concept of simplified calculation method
3.2 Damage class definition of RC beams
The damage classes of the columns and walls are originally defined based on themechanical properties, such as yielding of tensile rebars (JBDPA, 2001). In orderto classify the damage class easily on-site, the relationships between the damage
class and visual damage information, such as maximum residual crack width, aredefined as well (JBDPA, 2001).
Since such a damage class is not clearly defined for RC beams, in this paper, their
damage classes are first defined by the mechanical properties, such as cracking,yielding of reinforcement and maximum shear strength, as shown in Figure 8.
Then, the maximum residual crack widths according to the damage classes arecalculated based on Figure 9, which is obtained from the 2SH-64 specimen test
results. Considering the crack width of 1mm, which is widely used as boundary ofthe damage class in previous research, damage class Ⅱ of the RC beams isdivided into Ⅱ- and Ⅱ+, even though it is not governed by mechanical properties.
The damage class definition for the RC beams is described in details as shown in
Table 4.

Damage Class based on
Visual Damage Information

Ⅰ

Ⅱ

Ⅱ-

Ⅱ+

Ⅲ

Ⅳ

Ⅲ

Ⅳ

Yielding of hoops
Maximum residual crack width 1mm
Yielding of tensile rebars
Cracking

Maximum strength(Local crush of concrete cover)Deflection

Ⅰ

Maximum residual crack width(mm)

Ⅰ

Load Carrying Capacity

Damage Class based on
Mechanical Property

6

Ⅲ

Ⅱ

Ⅳ

①Yielding of tensile rebars

5 ②Yielding of hoops③Maximum strength

4

③

②

3
2
1
0

①

0

1

2

3

Drift angle (%)

4

Figure 8: Damage class definition of RC beams Figure 9: Relations of damage classbased on mechanical property
and maximum residual crack width
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Table 4: Damage class definition of RC beams
Damage class based on
Damage class based on Detail ofBoundarymechanical property properties value of wmax visual damage information
Yielding ofⅠⅠ
w =0.2mm
tensile rebars max
Ⅱwmax=1.0mm
Ⅱ
Ⅱ+
Yielding of
wmax>2.0mm
hoops
Ⅲ
Ⅲ
wmax>4.0mm
Maximum
Local crush ofstrengthⅣⅣ
concrete cover

wmax: maximum residual crack width

3.3 Seismic capacity reduction factor η of RC beams
The seismic capacity reduction factor η of a RC beam is calculated based on theprevious method developed by BUNNO et al. in 2000. The factor η calculated
from the load-deflection curve of left beam in 2SH-64 specimen, which ismeasured from the difference of vertical load between the left and center column,
is shown in Figure 10. Also, the lower limit value of the factor η according to eachdamage class of the RC beams mentioned above is shown in Table 5.
Damage Class

Ⅰ

Ⅲ+

Ⅱ-

Ⅳ

Ⅴ

1.0

Table 5: Relationships between
factor η and damage classes

Factor η

0.8
0.6
0.4
0.2
0.0

0

1

2

3

Drift angle (%)

4

Figure 10: Calculation results of factor η(left beam of 2SH-64 specimen)

Damage Class
Ⅰ
ⅡⅡ+
Ⅲ
Ⅳ

Factor η
0.99
0.90
0.70
0.30
0

3.4 Energy contribution coefficient α of structural members
The energy contribution coefficient α of a structural member, which means theenergy absorption rate of the member for a building, is originally defined as theratio of its dissipated energy to the dissipated energy of particular member. In thisresearch, the particular member, which is also named critical member, is definedas the member that yields last. Since the dissipated energy of each structuralmember is difficult to grasp on-site, in this paper, the coefficient α of the member
is defined as the ratio of its yield moment to the yield moment of the criticalmember. If the definition is valid, the coefficient α can be taken as a fixed value.
In order to compare these two methods mentioned above, the coefficient α of thedifferent members is calculated based on the 2SH-64 specimen test results (left840

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column is taken as a critical member) as shown in Table 6. It can be found that thecoefficient α calculated by these two methods is approximately equal to eachother. As a result, the calculation method for coefficient α based on the yield
moment of members is validated.
Since the center column of 2SH-64 specimen is damaged as flexible member due
to the damage of the spandrel wall, the value of its coefficient α is taken as 1.0 in
this paper. For the 1SF test specimen in that the beam is the critical member, thecoefficient α of each column is taken as 1.39.
Table 6: Coefficient α of members for the 2SH-64 specimen
Coefficient α
Based on dissipated energy
Based on yield moment
Right column
0.97
1.0
Right beam
0.63
0.65
Left beam
0.62
0.65
Member

3.5 Definition of simplified calculation method for index SImargin
According to the above results, the simplified calculation method of index SImargin
can be defined as Equation (2).
Ⅴ  k    k , D  Ak , D 

SI m arg in  kD Ⅰ  Akk

100 % (2)kwhere, k: type of the member (such as ductile/brittle column or beam), D: thedamage class of member (0 through Ⅴ), αk: the energy contribution coefficient ofk type member, ηk,D: seismic capacity reduction factor of k type member having
the damage class D, Ak,D: the number of k type members having the damage class
D, Ak: the number of k type members.
4. COMPARISON BETWEEN DETAILED AND SIMPLIFIEDCALCULATION METHOD OF INDEX SImargin
In order to verify the validity of the simplified calculation method for the index
SImargin, the detailed and simplified methods are applied to the 2SH-64 specimen
and 1SF specimen test results, and calculation results of the index SImargin arecompared as shown in Figure 11.
Figure 11(a) shows that the index SImargin of the 2SH-64 specimen based on thedetailed and simplified methods is approximately equal to each other. However,
the index SImargin of the 1SF specimen calculated by the simplified method asshown in Figure 11(b) is lower than the calculation result based on the detailed
method. It can be considered that the simplified calculation method is not suitablefor evaluating the effect of non-structural walls to the residual seismic capacity ofoverall frame. Therefore, it is necessary to propose an upgraded simplified
calculation method for the index SImargin, which will also consider the damage of
non-structural walls in the further research.
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frame with weak-beams based on energy
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B

C

Index SImargin (%)

100

D

A

B

C

D

detailed calculation method
simplified calculation method

80
60
40
20
0
0

(a)2SH-64 specimen

12(b)1SF specimen

3

Drift angle (%)

4

5 0

1

2

3

Drift angle (%)

4

5

Figure 11: Detailed vs. simplified calculation method for index SImargin
5. CONCLUSIONSIn this paper, a method which can evaluate the residual seismic capacity of weakbeam RC frames damaged by earthquakes is developed. The results can besummarized as follows:(1) The boundary values of the index SImargin classifying the damage ratings (FromA to D) are calculated to define the damage rating criteria.
(2) The damage classes of RC beams are defined based on their mechanicalproperties. Then, the maximum residual crack width and the seismic capacity
reduction factor η corresponding to the damage classes are calculated using
the 2SH-64 specimen test results.
(3) The energy contribution coefficient α calculated by the dissipated energy ratio
and calculated by yield moment ratio has almost the same value.
(4) The index SImargin of the 2SH-64 specimen is similar when it is calculated
based on the detailed and simplified calculation methods. However, the index
SImargin of the 1SF specimen is estimated to have smaller value for thesimplified calculation method.
REFERENCES
The Japan Building Disaster Prevention Association (JBDPA), 1991 (revised in 2001).
Guidelines for Post-earthquake Damage Evaluation and Rehabilitation. (in Japanese)
Architectural Institute of Japan (AIJ), 1980. Reconnaissance Report of the 1978
Miyagiken-Oki Earthquake. (in Japanese)
Institute of Industrial Science of the University of Tokyo and Horie Architecture
Engineering Institute (IIS & HAEI), 2011. Test Results Report for Advancementof Seismic Evaluation Method. (in Japanese)
Building Research Institute (BRI), 2011. Proceedings of Development on New
Structural Performance Evaluation System for Disaster Resilient Buildings. BRI
Proceedings, No.20. (in Japanese)
BUNNO, M., MAEDA, M. and NAGATA M., 2000. A study of the damage level
estimation of RC buildings based on residual seismic capacity of members.
Proceedings of the Japan Concrete Institute, Vol.22, No.3, PP.1447-1452. (in Japanese)842

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Low temperature behavior and modelingof high damping rubber bearings
Tomoya MATSUMOTO1, Yoshiaki OKUI1, Dung Anh NGUYEN1, Md. Shafquat
HASAN1, Kaho TAKAHASHI2, Hiroshi MITAMURA3, Takashi IMAI4
Department of Civil and Environmental Engineering, Saitama University, Japans13me127@mail.saitama-u.ac.jp
2
Omiya branch office, East Japan Railway Company, Japan
3
Civil Engineering Research Institute for Cold Region Sapporo, Japan
4
Rubber Bearing Association, Japan
ABSTRACTIn Japan, high damping rubber bearings have been widely used as isolated
devices since the Kobe Earthquake in 1995. The rubber bearings have various
characteristics, such as temperature dependence, self-heating effect and, so on.
Besides, in current Japanese Specifications of Highway Bridges, temperatureeffect on behavior of rubber bearings is not considered. In this paper, temperature
increases in high damping rubber bearings under cyclic loading and their effects
on seismic performance of a viaduct at low ambient temperatures are investigated.
Experimental results of cyclic loading show that the temperature inside rubber
bearings increase by approximately 27°C. Moreover the equivalent stiffness andthe equivalent damping constant of rubber bearings are changing with increasing
inside temperature. The equivalent stiffness at an ambient temperature of -20°C
reported by Rubber Bearing Association in Japan is 2.19MPa. However, it isfound that the equivalent stiffness at an inside temperature of -20°C is 3.76MPa.
In this paper, nonlinear seismic response analysis with the bilinear model for low
temperature is carried out.
Keywords: high damping rubber bearings, temperature dependence, self-heating
effect, seismic response, bilinear model.
1. INTRODUCTION
1.1 BackgroundIn recent years base isolation has become an increasingly applied to structuraldesign technique for buildings and bridges in highly seismic areas. Various tapes
types of base-isolation devices have been developed. Above all, high damping
rubber bearings (HDRB) are widely applied to bridges. However, it is known that
HDRBs have various characteristics, such as temperature dependence, selfheating effect and, so on. These characteristics may have adverse effects on theseismic performance of bridges with HDRBs, especially, in cold districts. The
temperature effects on behavior of rubber bearings are not considered in seismic
design based on current Japanese Specifications of Highway Bridges.

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In this paper, the mechanical behavior of HDRB at low ambient temperatures areinvestigated with considering self-heating. Furthermore, the low temperatureeffect on the seismic performance of a viaduct is examined through nonlinear
seismic response analysis.
2. Experiments under low temperature
2.1 Specimen and loading condition
In order to investigate the mechanical behavior of HDRB under low temperatures,
cyclic loading tests at ambient temperatures of 23°C, -20°C, and -30°C wereconducted, in which sinusoidal loading with a shear strain amplitude of 1.75 and
0.5Hz frequency was applied. The geometry and material properties of thespecimens are given in Table 1 and illustrated in Fig. 1. The temperatures insidespecimens were measured with thermocouples at the points shown in Fig. 2. The
specimens were tested under shear deformation with an average constant verticalcompressive stress of 6MPa.

A(5mm x 6layers)(2.3mm x 5))
Figure 1: Dimensions of specimen [mm]Table 1: Dimensions and material property of HDRB specimen
Particulars
Specifications
2
Cross-section [mm ]240×240
Number of rubber layers
6
Thickness of one rubber layer [mm]5Thickness of steel layer [mm]2.3Nominal shear Modulus [MPa]
1.2

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Figure 2: Measurements points of inside temperatures (Civil Engineering
Research Institute for Cold Region, et al. 2009)
2.2 Experimental results and discussion
Figure 3 (a)-(c) illustrates the shear stress-strain relationships obtained from thesinusoidal loading tests at different ambient temperatures, and the corresponding
temperature history inside the specimens are shown in Fig. 4 (a)-(c). The shear
stress at low temperatures is larger than that at room temperature. The insidetemperature rise at lower temperatures is larger than that at room temperature. Fig.
5 shows the stress-strain relationships obtained from a loading cycle at the same
inside temperatures and different ambient temperatures. Although the stress-strain
relationship in the first cycle of Fig. 5(a) is affected by the initial condition,
HDRBs with the same inside temperature exhibit the identical stress-strain curve.

(a): -30°C ambient temperature(b): -20°C ambient temperature(c): 23°C ambient temperature
Figure 3: Stress-strain relationship

Low temperature
behavior andbehavior
modelingandof modelinghigh damping
rubberbearings
Low temperatureof high
dampingrubber bearings

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Vietnam(a): Temperature history at -30°C
ambient temperature(b): Temperature history at -20°C
ambient temperature(c): Temperature history at 23°C
ambient temperature
Figure 4: Inside temperature history(a) -20°C inside temperature(b) -10°C inside temperature

Figure 5: Stress-strain relationship at the same inside temperatures and different
ambient temperatures
In addition to the experimental results, the bilinear models for seismic design
analysis are also plotted in Fig. 5. These bilinear models (Takahashi, 2009) areused in the subsequent nonlinear seismic response analysis of a viaduct.

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3. Nonlinear seismic response analysis of a viaduct
3.1 Model viaduct and earthquake wave
Fig. 6 shows dimensions of a physical model of a viaduct. The model viaduct is afive-span continuous steel-concrete composite girder bridge isolated with HDRBs.
The dimensions of this model bridge including HDRBs are determined bydesigning in accordance with Japanese Specifications of Highway Bridges (JSHB)(JRA, 2013) under the room temperature condition. Fig. 7 shows the analyticalmodel of bridge system. The dimensions and material properties are shown in
Table 2.
The superstructure is modeled with elastic beam elements. The concrete piers aremodeled with elastic beam elements with a plastic hinge. Takaeda tri-linear modelis used to express the nonlinear hysteresis behavior of the plastic hinge in eachpier. The ground acceleration history used in the analysis is presented in Fig. 8,
which is specified in JSHB for level-2 type-1 (1-1-2) earthquake.

(a) Side view(c) Concrete brigdepier(b) Cross section of superstructure
Figure 6: Model bridge for seismic analysis (Razzaq et al., 2012)

Figure 7: Analytical model of bridge (Razzaq et al., 2012)

Low temperature behavior
and modelingof high anddampingrubberbearings
Low temperature
behavior
modelingof high
damping rubber bearings

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Table 2: Geometric and material properties of the pierProperties
Cross-section of the pier cap [mm2] B1 x W1
Cross-section of the pier body [mm2] B2 x W2
Cross-section of the footing [mm2] B3 x W3
Number of piles/pierYoung’s Modulus of concrete [MPa]Young’s Modulus of steel [MPa]Specifications
Pier S1 & S2 Pier P1 to P4
3300×9600
2000×9600
3300×6000
2000×6000
5000×8000
5000×8000
4
25000
200000Figure 8: Typical ground acceleration history used in seismic response
analysis
3.2 Analytical results
Fig. 9 shows the analytical results at -20°C as an example. Fig. 9(a) shows thestress-strain response of a HDRB, and Fig. 9(b) does the moment-rotation
response of the plastic hinge of a pier.

(a) Shear stress-strain response of
HDRB(b) Moment-rotation response ofplastic hinge of pierFigure 9: Seismic response of the Tohoku earthquake (1-1-2) (-20°C)

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ICUS Report 73(a) Maximum shear strain(b) Maximum rotation ratio

Figure 10: Comparison of maximum shear strain and rotation ratio among
different inside temperatures
4. Summary
The experimental results of sinusoidal loading tests after several loading cycles
are often used to identify a seismic design model of high damping rubber bearings,
such as the bilinear model. The present cyclic loading test results of high damping
rubber bearings at low ambient temperatures shows that the temperature rises
inside the bearings due to cyclic loading attain to 27°C after 11 loading cycles at 30°C ambient temperature. The temperature rises inside the rubber bearings affectmechanical properties such as stiffness and equivalent damping, especially at low
temperatures. The present results suggest that a design model of high damping
bearings ignoring the self-heating may provide false seismic response, since thetemperature rises under a seismic wave are considered to be not so large as thosein a cyclic loading test. Finally, the nonlinear seismic response analysis of a
viaduct based on the inside temperatures shows the maximum response of
concrete piers at -10°C becomes 5 times larger than those at 23°C, which
demonstrates the importance of considering temperature dependency of highdamping rubber bearings at low temperatures.
REFERENCES
Japan Road Assocication, 2012. Specifications for Highway Bridges, Part V:
Seismic Design. Maruzen, Tokyo.
Incorporated Administrative Agency Pubic Works Research Institute Civil
Engineering Research Institute for Cold Region, Hokubu consultant Co. LTD,
2009. Report on seismic performance of bridges in cold district.
Razzaq, M. K., 2009. Seismic Response Prediction of Base Isolated Multi-Span
Highway Bridge with Different Modeling Techniques for for Lead Rubber
Bearings, Satiama University Master thesis.
Takahashi, K., 2012. Modeling of high damping rubber bearings at low
temperatures, Satiama University Graduation thesis.
Razzaq, M. K., Okui, Y., Bhuiyan, A. R., Amin, A. F. M. S., Mitamura, H. Imai,
Low temperature behavior and modeling of high damping rubber bearings

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VietnamT., 2012. Application of Rheology Modeling to Natural Rubber and Lead Rubber
Bearings: A Simplified Model and Low Temperature Behavior, Journal of Japan
Society of Civil Engineerings, Ser A1 (Structural Engineering and Earthquake
Engineering (SE/EE)) Vol.68 No.3, 526-541.

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The structural performance oftraditional frames with through columns
about townhouses in Japan
Hiromi SATO1, Mikio KOSHIHARA2 and Tatsuya MIYAKE3
1
Research Associate, IIS, The University of Tokyo, Japan
Sato310@iis.u-tokyo.ac.jp
2
Professor, IIS, The University of Tokyo, Japan
3
President, Nihon System Sekkei Architects & Engineers Co., Japan
ABSTRACTThis paper presents a study of the structural performance of traditional timber
townhouses in a historic town in Japan. The aim of this study was to clarify the
structural performance of traditional timber frame with through columns intownhouses. The target area has many traditional timber townhouses built in fromthe late of 18th century to the early 20th century and these townhouses have few
structural walls. In this study, static tests and seismic analysis of the frame withthrough columns were performed. As the results, it was clarified that thestructural performance of the frame with through columns and the structural
evaluation of the townhouses in this area was improved.
Keywords: Traditional timber construction, Static lateral loading test, Static
Analysis, Parametric study
1. INTRODUCTION
Japan has a long history of earthquakes and timber structures in Japan havesuffered great damage caused by strong earthquakes. Old traditional timber
structures suffered especially heavy damage. Besides, many of historical towns injapan have many traditional timber buildings that construction method is same ineach area. These traditional buildings often have insufficient earthquake-proof
performance. However, if the structural evaluation is suitable for thecharacteristics of their construction, the technique of earthquake-proofing suitable
for those buildings can be examined. Therefor it is important to clarify a suitableevaluation method in each historical area.
2. RESEARCH AREA
2.1 Sawara district
The research area of the present study is the Sawara district of Chiba Prefecture,
which is located near Tokyo. The Sawara district is a historical town arranged on
the riverside and contains traditional timber townhouse and storehouse with thick851

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Vietnamwalls (Figure 1). They are built in from the late of 18th century to the early 20th
century (The Sawara City, 2004). In townhouses in this area, the frontage
direction of the first floor has few walls and the frames which consist of throughcolumns.

Figure 1: View of the Sawara district
2.2 Previous earthquake disasterOn 11 March, 2011, timber structures suffered a great deal of damage due to the2011 off the Pacific coast of Tohoku Earthquake. This earthquake destroyed orseverely damaged 289 houses in the Katori city including the Sawara district. In
the Sawara district, many falls of roofing tiles, collapse of mud walls, andfoundation damage were observed.
2.3 Timber frame of through column
In the Sawara district, though the townhouses have few structural walls, they wereconstructed of many timber though columns. The column section of many of thethrough columns was larger than the jointed columns. The though columns havethe horizontal load resistance from bending back of column (Figure 2)(Architectural Institute of Japan, 2013).

h1 : height of the 1st floor
h2 : height of the 2nd floorδ1 : displacement of the 1st floor
δ2 : displacement of the 2nd floor
P1 : load of the 1st floor
P2 : load of the 2nd floor

Figure 2: Mechanism of bending back of though column

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3. STATIC LATERAL LOADING TEST
3.1 Measurement plan
The static lateral loading test was performed (Figure 3) (H. Sato et al, 2010, 2012).
The forces were applied by connecting the loading apparatus directly to the beamat the second floor level. The displacement and the strain of the columns were
measured using 45 displacement transducers and strain gauges.

Figure 3: Loading apparatus (section)
3.2 Specimens
The static test was performed on specimens of three types in the through column(Table 1). The A series was improvement column section larger. The B series hasoriginal column section of existing townhouse in the Sawara district. The columnof the C series change wood species to be stronger.
Table 1: Type of specimens
A series

B series

C series

Wide*depth (mm)180 * 150

150 * 165

150 *165

Young's modulus

1005 kN/cm2

822 kN/cm2

1162 kN/cm2

Wood species

Japanese ceder

Japanese ceder

Zelkova

Explanation

Improvement
column section
for new build

Original column
section ofexisting house

Change woodspecies (for newbuild)

Column section

The structural performance of traditional frames with through columns about townhouses
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3.3 Results of static test
3.3.1 Load-Displacement relationshipAs a result, the maximum strength, stiffness and failure mode was observed(Table 2). The average of the maximum load ranged from 17.8 to 32.0 kN. The
average of the secant stiffness at 1/30 rad ranged from 294.6 to 488.7 kN/rad. The
strength and stiffness of the B series were smaller than other two. The strength of
the C series has higher than others. About the stiffness, the A series wasapproximately equal the C series.
Table 2: The strength and the stiffness
Maximum load (kN)average
1
2
3
1
2
3
1
2
3

A

B

27.9
22.1
27.2
16.2
17.9
19.4
38.9
28.0
29.2

40

40

30

30

20

20
Load （kN）

Load （kN）

C

Stiffness (kN/rad.)average
588.5
25.7
488.7
456.4
421.0
295.2
17.8
294.6
272.5
316.0
538.2
32.0
484.5
453.2
462.1
*stiffness is the secant stiffness at 1/30 rad.

10

10
0

0

B1

A1
-10

-10

A2

-20
-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

B2
B3

A3
0.14

-20
-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

Deformation angle（rad.）Deformation angle（rad.）40
30

Load （kN）

20
10
0
C1
C2

-10

C3
-20
-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

Deformation angle（rad.）Figure 4: Load-Displacement relationship854

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3.3.2 Failure mode
In the all series, the displacement at first floor was ahead of the displacement at
second floor (Table 5). Besides, the failure mode was different from each series(Table 3). The failure mode of the A and B series was often collapse of thethrough column. By contrast, the failure mode of the C series was collapse of thetenon joint; that was not brittle fracture.

1/50
1/25
1/12
1/10

1/50
1/25
1/12
1/10

A series (A1)

1/50
1/25
1/12
1/10

B series (B2)

1/50
1/25
1/12
1/10

C series (C1)

Figure 5: Mode of deformation
Table 3 Failure mode

A

B

C

1
2
3
1
2
3
1
2
3

Failure mode
Collapse of the column at the sashikamoi joint
Collapse of the column at the 2nd floor level
Collapse of top and bottom of the column
Collapse of the tenon joint
Collapse of top of the column
Collapse of the column at the sashikamoi joint
Collapse of the tenon joint
Collapse of the tenon joint
Collapse of the tenon joint

3.3.3 Wall ratio
The results of the static test were evaluated to effective wall quantity as otherstructural walls (Table 4) (The Japan Building Disaster Prevention, 2004). The
wall ratio means the bearing strength per 1 meter and the wall quantity means thebearing strength per 1 frame in this study. The wall ratio of the frame with thetimber through columns equals to approximately half the value of timber brace.
Table 4: Effective wall ratio
Wall ratio*
Wall quantity*

A series
B series
C series
0.47
0.35
0.48
1.70
1.29
1.76
*
Average of 3 specimens and consideration in unevenness

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4. STATIC ANALYSIS
4.1 Model of analysis
The standard model of the analysis was based on the static test (Figure 6). The
model consists of two through columns and beam. The horizontal load resistanceelements were steel brace at the second floor as overall wall. The force carrying at
second floor level was repeated as the static test. In this analysis, the parameters
are the wall length (column span) and the opening pattern.

Figure 6: Analysis model (the standard model)
4.2 Results of analysis
The analyses were performed on the 9 models. The strength ratio was calculated
based on the maximum strength of analysis (Table 5). As the wall length became
to 1/2 or 1/4 times, the strength ratio became less than 1/2 or 1/4 times. The layoutof the openings was not so effective on the strength of the frame.
Table 5: The results of the analysis (the ratio of the strength) *1
Length*2

1P

2P

4P

0.22

0.36

1.00

1/2 length,
in the center

-

-

0.27

1/2 length,
in the end

-

0.23

0.37

Full
Opening

0.09

0.07

0.48

Second floor
Brace*3
Opening*4*1

the ratio is the each strength into the strength of the standard model
length is 910 mm per 1P*3brace is the steal brace of the static test*4
the wall type is the same as the standard model*2856

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5. CONCLUSION
In this study, static test and analysis were performed on the traditional timber
frame with through columns.
1) In the Sawara district, the traditional townhouse has few structural walls,
therefore the frame of through columns is important as structural element.
2) As a result of the static test, the maximum load ranged from 17.8 to 32.0 kN.
The secant stiffness at 1/30 rad ranged from 294.6 to 488.7 kN/rad. The failuremodes were collapse of through column or tenon joint. The structural
performance of the C series (Zelkova column) was higher than others.
3) As a result of the analysis, the wall length is very effective on the frame
strength in this study. The difference of opening layout or column span were
not became difference of the strength of the frame.
ACKNARIGEMENT
The authors express their appreciation to the members of the studies group of
townhouse of the Sawara district, without whose help these experiment would nothave succeeded.
REFERENCESThe Sawara City, 2004, Townscape of the Sawara district
Architectural Institute of Japan, 2013, Recommendation for structural calculationof traditional wood buildings by calculation of response and limit strength
The Japan Building Disaster Prevention Association, 2004, Seismic diagnosis andreinforcement of timber house
H. Sato and M. Koshihara, 2010, Horizontal load capacity of sashikamoi framewith through column, Summaries of Technical Papers of Annual Meeting
Architectural Institute of Japan, C-1, 569-570
H. Sato, M. Koshihara and T. Miyake,2012, Horizontal load capacity ofsashikamoi frame with through column Part 2 Effects of seismic performance of
second floor on through column, Summaries of Technical Papers of Annual
Meeting Architectural Institute of Japan, C-1, 461-462

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858

New Technologies for Urban Safety of Mega Cities in Asia

Modeling and earthquake response
analysis of traditional timber frames
including Kumimono
1

Iuko TSUWA1 and Mikio KOSHIHARA2
Gradutate Student, Graduate School of Engineering,
the University of Tokyo, Japantsuwa@iis.u-tokyo.ac.jp
2
Professor, Institute of Industrial Science,
the University of Tokyo, Japan

ABSTRACTIn building or renovating traditional timber structures such as temples andshrines in Japan, earthquake resistant design has been needed. However most of
traditional timber structures are built based on the knowledge and experience of
carpenters. The evaluation of seismic capacity for traditional timber structuresfrom the view point of modern engineering is indispensable. The purpose of thispaper is to quantitatively evaluate the seismic performance of traditional timber
frames including Kumimono. In this paper, we constructed the spring model ofseismic elements in three kinds of traditional timber frames including Kumimono
based on shaking table test results. In addition, we conducted the earthquake
response analysis with the models. The vibration characteristics of each frame arequantitatively compared based on both experimental and analytical results. The
way of modeling of such traditional timber frames are discussed.
Keywords: traditional timber structure, Kumimono, shaking table test, earthquake
response analysis,
1. INTRODUCTION
Earthquake resistant designed buildings are needed in building or renovating
traditional timber structures such as temples and shrines in Japan. Therefore thequantitative evaluation of their structural behaviors from the view point ofengineering is indispensable. When we build temples and shrines, column, mudwall, Nuki which is a tie beam extending from one pillar to another, and bracket
complexes called Kumimono in Japanese which is a structural component between
a column and roof, etc, are considered as structural elements. Each element has
been researched and modeled experimentally and analytically. However it is notclear how each element contributes to the whole structural behavior. In thisresearch, we performed shaking table tests with three kinds of traditional timber
frames. They have different wall stiffness. Specimen 1 had no wall. Specimen 2
had mud wall which is the smallest stiffness in such traditional timber frame. In
this time, we conducted shaking table tests about Specimen 3 including plywood859

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamwall as a wall with higher stiffness than Specimen 2. The aim of this research is toclarify the vibration characteristics of each element in a frame and the evaluation
method of traditional timber frame including Kumimono. Based on theexperimental results, we modeled each specimen with elastoplastic springs andperformed the earthquake response analysis. The analysis results were comparedwith experimental ones.
2. EXPERIMENT
We performed shaking table tests two kinds of frame as presented at USMCA
2009 (Tsuwa et al, 2009). One frame, Specimen 1, was composed with column,
Nuki and Kumimono. The other one, Specimen 2, was a frame added mud wall on
Specimen 1. The details were shown in the paper in 2009. We conducted anothershaking table test about Specimen 3 with a higher stiffness wall on Specimen 1.
We explain the experimental outline and the results of Specimen 3 comparing
with the results about Specimen 1 and 2.
2.1 Experimental method
The experimental method was shown in the Figure 2. The method was sameas Specimen 1 and 2. The timber frame was a frame used in the tests of Specimen
1 and 2 because the frame was not destroyed. However we replaced dowels atcolumn base with new ones because the dowels made shear deformation. In
Specimen 3, we used plywood wall as a wall with higher stiffness than mud wall.
We put the plywood walls between columns.
3060
1260

900

900
Toshi-hijiki

726

Kumimono

Column300

Mud wall

300

1980

2706

Daiwa

Koshi-nuki
Mud wallJi-nuki

Specimen 1

Specimen 2

Plywood wall

Specimen 3
Figure 1: Specimens

860

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Vertical Load

Specimen

Load cell
Shaking table

Figure 2: Experimental method
2.2 Experimental results

Figure 3 shows the relationship between shear force and horizontal
displacement gotten by inputting BCJ-L2 100% of Specimen 3. Figure 4 shows
the results from Specimen 1 and 2. In the result of Specimen 3, the load was
decreased sharply after the maximum load. The behavior of the specimen was
locking in BCJ-L2 100% test. Therefore the shear force of whole frame wasdecreased when a column base was going up.
30

（kN）

30
20

20

10

10
0

0
-200

-100

0
-10

（kN）

100

200

-200

(mm)

-100

0
-10

-20

-20

-30

-30

100

200
(mm)

S1
試験体3
S2
試験体2
試験体1
S3

Figure 3: The relationship between
load and displacement

Figure 4: The relationship between
load and displacement of bracket
complexes

3. EARTHQUAKE RESPONSE ANALYSIS
3.1 Modeling of restoring-force characteristics
We conducted earthquake response analysis with the elastoplastic frame
model. We considered springs as shown in Figure 5. The restoring-force
characteristics of each structural element were modeled as follows.

Modeling and earthquake response analysis of traditional timber frames including
Modeling andKumimono
earthquake response analysis of traditional timber frames including Kumimono861

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VietnamFigure 6: Analysis model
Column:The restoring force characteristic of columns wss calculated with anequation provided by previous experiments and researches of Ban, 1942 andKawai, 1992. The characteristic is shown in Figure 7. The hysteresis model was
nonlinear elasticity.
P

P

6

δ

H

H

Shear
force
せん断力
(kN)

柱の傾斜復元力Column

Shear
force

Column42柱の回転角(rad.)

0

h

b

θ

-0.1

-0.05

0

0.05

0.1

(rad.)(rad.)-2-4-6(a)Skelton curve(b) Hysteresis model

Figure 7: The restoring force characteristics of Column
The joints of a column and Kosihnuki:
The relationship of bending moment of column-Koshinuki joint was gotten
from experiments in each specimen. On the base of experimental results, theskeleton curve of the restoring force characteristic was determined. The
characteristic is shown in Figure 8. The skeleton curve was different with eachspecimen. We used a same frame in all tests. Therefore the compressive strains
inclined to the grain occured repeatedly at column-Koshinuki joints. The
resistance force of column-Koshinuki joint was decreased every specimen.
Moment (kN/rad.)

d/2

S2

3000

S3

2000

(rad.)

1000
0

Koshinuki
腰貫

-0.15

d/2
＋

S1

Column柱(西)ーθ5000 曲げモーメント(kN･mm)
4000

-0.1

-0.05

-1000

0

0.05

0.1
0.15
回転角 (rad.)

-2000

d

-3000
-4000
-5000

(a)Skelton curve

試験体1
試験体2
試験体3
モデル1
モデル2
モデル3

(b) Hysteresis model

Figure 8: The restoring force characteristics of Koshi-nuki

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The joints of columns and Jinuki:
The bending moment of column-Jinuki joint was defined by Merikomi
theory (Inayama, 1992), because we did not get the experimental results like
Koshinuki. The hysteresis model was same as Koshinuki.
Shear
force
せん断力

4

柱(西)
Columnθ(kN)

3

地貫のめり込み
Jinuki2d10Jinuki
地貫

-0.1

-0.05

-1

0

0.05

0.1

柱の回転角(rad.)Deformation-2

anlgle(rad.)-3-4(a)Skelton curve(b) Hysteresis model

Figure 9: The restoring force characteristics of Jinuki
Kumimono:
Each relationship between load and displacement of Kumimono in all
specimens was gotten as shown in Figure 10. The skeleton curve for analysis was
defined such as red line. The hysteresis curve was bilinear model. The yielddisplacement was 2.6 mm. The yield load was 46.5 kN. The second stiffness was
0.4 times as high as the first one.
(kN)

（kN）

30
20
10

(mm)

0
-15

-10

-5

0

5

-10
-20
-30

(a)Skelton curve

10

15

S1
試験体2

(mm)

S2
試験体3
試験体1
S3

モデル
Model

(b) Hysteresis model

Figure 10: The restoring force characteristics of Kumimono
Mud wall:
The mud wall was destroyed during the test of BCJ-L2 100% in Specimen 2.
Therefore the shear force of the whole specimen was decreased as shown in
Figure 11. We defined the skeleton curve of mud wall from the experimental
result. About each wall upper and lower Koshinuki, we defined each skeleton
curve as shown in Figure 11.The shear force of the lower wall was zero at the
deformation angle 0.03 rad. Both curves were bi-linear slip.

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(kN)
15
100%

復元力(kN)

10
5
0
-150

-100

-50

0

錘の水平変位(mm)
(mm)
50
100
150

-5
-10

Beforedestroy
土壁崩壊前
After
destroy
土壁崩壊後-15

Figure 11: The restoring force characteristics of Mudwall

11 [kN]
上壁
Upper wall
10
9
下壁
Lower wall
8
全体
All
7
6
5
4
3
2
1
(rad.)
0[rad.]
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1

ijiki
ono
a
mn

Mud wallnuki
Mud wallki(a)Skelton curve(b) Hysteresis model

Figure 12: The restoring force characteristics of Kumimono
Plywood wall:
The restoring force characteristic of plywood wall was defined from theshear force of surface bars and nails as shown in Murakami et al, 2006. The
skeleton curve was as shown in Figure 13.
(kN)

30
合板
20
10
0
-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

-10

0.2
(rad.)-20-30(a)Skelton curve(b) Hysteresis model

Figure 13: The restoring force characteristics of Plywood wall
The deformation characteristic of a specimen was different in eachspecimen as shown in Figure 14. In Specimen 1 and 2, the whole frame was shear
deformation. On the other hand, locking deformation was seen in Specimen 3.
Therfore, we evaluated a column base every specimen. We set an analysis

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condition as follows. A base column did not go up in Specimen 1 and 2. A basecolumn went up in Specimen 3.

Specimen 1

Specimen 2

Specimen 3

Figure 14: The characteristics of deformation
3.2 Analysis method
We used an improved analysis soft called wallstat ver2.0.1 (Nakagawa,2006). Damping factor was 2.0 %. We analyzed about BJC-L2 100% which was
the first maximum input wave.
3.3 Analysis results
The time history response wave until 60 sec is shown in Figure15. In all
specimens, analysis results almost corresponded with experimental results. The
difference between an experimental and analysis result in Specimen 3 was larger
than one of Specimen 1 and 2. In the results of load-displacement relationship in
Figure 16, almost same tendency was seen. In the result of specimen 3, the shear
force was increased again after the deformation of 50 mm. The resistance force
went up with the increasing deformation of a whole frame. It is possible because
the compressive strain inclined to the grain was increased at the corner of wall. It
can be seen that these results occurred because Specimen 3 was locking. It needs
to reconsider the evaluation of behavior after locking.
4. CONCLUSIONSIn this paper, we conducted the earthquake response analysis of three kindsof specimen based on the experimental results. We made the frame model
considered springs of column, the joint of column-batten, Kumimono, and wall.
When the stiffness of walls was high like Specimen 3, it is possible that a wholeframe is locking. In this case, it needs to consider it the base column of a frame
goes up in an analysis. However the shear force of a frame was increased again
after the force was decreased sharply. The analysis results were different withexperimental results about this behavior of Specimen 3. We need to examine theevaluation of this phenomenon more.

Modeling and earthquake response analysis of traditional timber frames including
Modeling andKumimono
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200

Analysis
Experiment

150
100
50
0
-50 0

10

20

30

40

50

60
(sec)

-100

Specimen 1

-150
-200

200

䡉䡉

Analysis
Experiment

150
100
50
0
-50 0

10

20

30

40

50

60
(sec)

-100

Specimen 2

-150
-200

200 䡉䡉

Analysis
Experiment

150
100
50
0
-50 0

10

20

30

40

50

60
(sec)

-100

Specimen 3

-150
-200

Figure 15: Time history response wave

(kN)

15

Experiment
Analysis

10
5
0
-300

-200

-100

0

100

200

-5

300
(mm)

-10

Specimen 1

-15

20

(kN)

30

Experiment
Analysis

15(kN)

Experiment
Analysis

20

10

10

5

0

0
-300

-200

-100

-5

0

100

200

300
(mm)

-300

-200

-100

0
-10

-10
-15
-20

100

200

300
(mm)

-20

Specimen 2

Specimen 3-30

Figure 16: The relationship between load and displacement of analysis

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REFERENCES
Tsuwa, I., Koshihara, M., 2009. Shaking table tests of traditional timber
frames including Kumimono - Modeling of horizontal resistance force -, USMCA
2009
Tsuwa, I., Koshihara, M., 2011. A study on the effect of wall stiffness on
the vibration characteristics of traditional timber frames including Kumimono,
USMCA 2011
Ban, S., 1942. A study on the determination of the stability about main hall
structures, Vol. 3: a mechanical study on the Japanese Traditional Frame, 1, thestability restoring force of a column. Papers of annual meeting of Architectural
Institute of Japan, March, 252-258. (in Japanese).
Kawai, N., 1992. A study on the structural stability of traditional timber
structures, Report of the Building Center of Japan, March. (in Japanese).
Inayama, M., 1991. The theory of compression perpendicular to the grain inwood and its application, Dissertation of the University of Tokyo. (in Japanese).
Murakami, M., Inayama, M., 2006. Formulae to predict the elastic andplastic behaviour of sheathed walls with any nailing aprangement pattern, Journalof structural and construction engineering, No.519, pp.87-94, (in Japanese).
Nakagawa, T., Ohta, M., et. al. 2010. "Collapsing process simulations oftimber structures under dynamic loading III: Numerical simulations of the real
size wooden houses", Journal of Wood Science, Vol.56, No.4, p.284-292
Kato, K., Tsuwa, I., and Koshihara, M., 2008. Shaking table tests oftraditional timber frames including Kumimono Part 1 Experimental outline andresults, Summaries of technical papers of Annual Meeting Architectural Instituteof Japan, C-1, Structures III, pp.43-44 (in Japanese).
Tsuwa, I., Kato, K., and Koshihara, M., 2008. Shaking table tests oftraditional timber frames including Kumimono Part 2 Modeling of horizontal
resistance force and the analysis, Summaries of technical papers of Annual
Meeting Architectural Institute of Japan, C-1, Structures III, pp.45-46 (inJapanese).
Tsuwa, I., and Koshihara, M., 2012. S Shaking Table Tests of Traditional
Timber Frames including Kumimono Part 3 Effect of a wall stiffness on structural
behavior, Summaries of technical papers of Annual Meeting Architectural
Institute of Japan, Structures III, pp.425-426, (in Japanese).
Tsuwa, I., and Koshihara, M., 2013. S Shaking Table Tests of Traditional
Timber Frames including Kumimono Part 4 Earthquake Response Analysis andComparisons with Experimental Results, Summaries of technical papers ofAnnual Meeting Architectural Institute of Japan, Structures III, pp.467-468, (inJapanese).

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Modeling andKumimono
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868

New Technologies for Urban Safety of Mega Cities in Asia

Optimization of PP-band Mesh Connectivity
for Cost and Time Effectiveness in Seismic
Retrofitting of Masonry Structures
Adnan Mahmood DAR, Saleem M. UMAIR2, Muneyoshi NUMADA3,
Kimiro MEGURO4
1
Graduate Student, Department of Civil Engineering,
The University of Tokyo Japanadnan@iis.u-tokyo.ac.jp
2
PhD Student, Department of Civil Engineering,
The University of Tokyo Japanmumair@iis.u-tokyo.ac.jp
3
Research Associate, ICUS, Institute of Industrial Science,
The University of Tokyo, Japannuma@iis.u-tokyo.ac.jp
4
Professor and Director, ICUS, Institute of Industrial Science,
The University of Tokyo, Japanmeguro@iis.u-tokyo.ac.jp
ABSTRACT
Being common attraction for the people as economic viable solution for housing,unreinforced masonry (URM) construction has been economical and locallyavailable in every part of the world with different types and form. Performance of
URM masonry structures during different earthquake is still big question markand has posed serious threats to human life in the past and future seismic
disasters. The highest fatality rates during any earthquakes were always
associated with masonry housing. Enhancing the performance of brick masonry inparticular during the earthquake with material which will be cheap and having
better performance during the earthquake have been dream of researcher andpracticing engineer. The Polypropylene band (PP-band) retrofitting has beenused for the retrofitting of masonry structures in many under developing countries.
PP-band has been used as mesh on the walls with plaster coating. In the past
behavior of PP-band is investigated during dynamic testing on small and fullscale masonry houses. The PP-band applied on the masonry wall are connected
at every intersection of the mesh. In the current research work an attempt wasmade by reducing the PP-band mesh connectivity for reaching the optimization inmanner of time and cost for retrofitting of URM masonry structure. By varying
these parameters we can propose a solution of PP-band retrofitting with less workforce, price and duration by testing them in ¼ scale model on shake table test.
Comparison of PP-band mesh performance having its connectivity at all points
and with zero points has been made in damaged assessment of the structure.
Keywords: Unreinforced Masonry, performance, retrofitting, brick masonry.

869

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1. INTRODUCTION & LITERATURE REVIEW
Masonry construction is the Popular and widely adopted in almost all continents
of world. Economically affordable and locally available material for unreinforced
masonry (URM) makes it attractive choice to adopt for housing purpose. Masonry
construction poses serious life threats to human safety during the events ofearthquake. Even though the human suffering during the earthquake cause hugeproblem for masonry housing but still new construction is far from stopping. The
steps are required to overcome the problem of safety during earthquake with sometechniques which are economical, locally available and socially acceptable.
The numbers of researcher are working on enhancing the performance of masonry
retrofitting with different materials. In the past few years university of Tokyo
research group working with PP-band (polypropylene) used as packing material in
the cargo industry. The PP-band was utilized as retrofitting material for masonry
construction has been developed by (Mayorca and Meguro, 2004). Many different
aspects have been studied by Meguro Laboratory, Institute of Industrial Science,
The University of Tokyo (Sathiparan, 2008).
Masonry with single story with regular brick has been common construction in the
different part of the world. Masonry houses with stone, adobe and brick arecommon material adopted for construction of the house. The single story houses
with PP-band mesh have been evaluated on the ¼ scale model with roof on Shaketable test. The seismic performance for the PP-band retrofitted model has beenenhanced in comparison to Non-retrofitted Model figure-1a) Non retrofitted Modelb) PP-band retrofitted Model

Figure-1 Condition of Model house at Frequency 5 Hz and Acceleration 0.4 g
2. RESEARCH OBJECTIVE
During the past research PP-band has been study to increase seismic performance
which has been verified by number of researcher but connecting PP-band with PPband welder and connecting all point is time consuming and requires extensive
work time and cost. So there is need to investigate the reduced mesh connectivity
for PP-band.

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In this study we like to study the effect the PP-band mesh connectivity by varying
them from all point of mesh connected with PP-band to non-connected in figure-2.
We will keep the out-plane connectivity with wall and mesh pitch constant for
both retrofitted houses. Three brick masonry model houses of ¼ scale with URM,
PP-band mesh fully connected and non-connected were tested on shake table testby varying frequency and acceleration. By this study we can suggest reduction inconnectivity of mesh and retrofitting time-cost.

a) Fully connected Meshb) Non Connected mesh

Figure-2 PP-band mesh connectivity for Model house
3. MATERIALS PROPERTIES
3.1 Masonry Properties
In making the model house the burnt bricks with 75 mm x 50 mm x 37.5 mm
dimension and mortar from cement, sand, lime(1:7.9:20) with w/c 0.4 (water
cement ratio). The thickness of mortar kept around 5 mm for masonry
construction. After curing for 28 days and tested for material properties ofmasonry using the setup shown in figure-3.

a) Compressive Strengthb) Shear Strengthc) Bond strength

Figure-3 Layout of material testing for masonry (unit: mm)
The effort was made replica of brick masonry in the developing countries andmechanical properties are shown in table-1.
Table-1 Mechanical Properties of Masonry
Property
Compressive Strength (Mpa)
Shear Strength (MPa)
Bond Strength (Mpa)

Fully Connected
13.60
0.021
0.0028

Non-Connected
13.45
0.018
0.0027of PP-bandmesh connectivity
costEffectivenessand time effectiveness in seismic
OptimizationOptimizationof PP-band Mesh
Connectivity
for Cost andforTime
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Vietnam

3.2 Polypropylene (PP) Properties
PP-band of size 6mm x 0.5 mm was used and thickness not uniform due to surface
corrugation. Three band were tested under uniaxial tensile test and band fixed at
one end and force applied from other end. The distance between two ends is 150
mm. The PP-band exhibit the 13 % axial strain, 6.80 GPa initial modulus and 1.98
GPa of final modulus.
4. CONSTRUCTION OF HOUSE MODEL
4.1 Shaking Table Description.
Shake table installed in IIS University of Tokyo have dimension of 1.5 m x 1.5 m
having maximum weight of specimens of 2000 Kg. It has capability of controlling6 degree of freedom, frequency ranging from 0.1 to 5 Hz and displacement ± 100
mm. Adopted house model with ¼ scale selected in keeping in mind the limitationof shake table.
4.2 Construction of House Model.
Concrete foundation were used for building the house and form erected initially.
The base dimensions of the house were 930 mm x 930 mm and 720 mm height ofthe box shown in Figure-4(a). The 18 layer of brick with wall thickness 50 mm
used with mortar having cement, sand, lime ratio as (1:7.9:20) with w/c as 0.4(water cement ratio).Lintel were placed above the door and window having
dimension were245 mm x 485 mm and 245 mm x 325 mm.

a) Construction of houseb)Completed house

Figure-4 Phases of construction
The effort is made to make replica model similar to developing countries masonryhouses in terms of strength. The straw were placed at bottom layer and after every
fourth layer for Out of Plane connection of PP-band with brick wall. At the top
layers cement bricks with bolt were placed along with brick in same mortar. The
form work was removed after 7 days and sprinkled with water for same duration.
The 28 days were given to house to gain strength. Wooden piece of 30mm x 50
mm are placed at top layer for providing level surface for placement of wooden
roof truss Figure 4(b).

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4.3 Retrofitting techniques.
Retrofitting scheme needs to be simple and easily employed by local people at site.
Model with fully connected mesh was made by Cutting piece of PP-band (6m x
0.5mm) for horizontal and vertical length. The out of Plan connection was madewith steel wire through the wall in figure-5(a). The horizontal piece at the bottom
was attached outside and inside with ultra-sonic pulse welding device and thenconnected with out of plane connection. The vertical Piece was attached at pitchof 50 mm with bottom piece of PP-band as shown in figure-5(b). After attaching
all the vertical pieces and then remaining horizontal pieces are placed at pitch of
50 mm. Then connected with out of plane for remaining connections. Arounddoor and windows were warped for better holding of PP-band and mesh areconnected at every intersection. Figure-5(c)a) Out of plane connection with wallb) Attaching vertical withhorizontal PP-bandc) Fully connected PPband mesh

Figure-5 Retrofitting Phases for Fully Connected House
Model house with non-connected PP-band is made by attaching horizontal piece
inside and outside at bottom with out of plane connection shown in figure- 5(a).
Attaching the vertical piece with bottom PP-band with pitch of mesh horizontally
pitch 50 mm. Attaching horizontal plane by waving the horizontal PP-band as
shown in figure-6(a). Connecting PP-band mesh at level of out of plane ofconnection to make have better grip. Attach remaining horizontal PP-band meshinside and outside at pitch of vertical 50 mm. Warp the mesh around doors andwindows opening as shown in Figure-6(c). The PP-band mesh is not connectedwith ultra-sonic welding device and only waving has been done to make the mesh.

a) Waving for Horizontal
PP-bandb) Inside View of houseduring retrofittingc) Non Connected PPband house

Figure-6 Retrofitting Phases for Non-connected PP-band House.
of PP-bandmesh connectivity
costEffectivenessand time effectiveness in seismic
OptimizationOptimizationof PP-band Mesh
Connectivity
for Cost andforTime
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in Seismic Retrofitting of Masonry Structures873

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamRetrofitting for both fully connected and non-connected house have been
described in the table-2 explaining the two people have work on the retrofitting of
the house. Retrofitting for fully connected 0.13 m2/hrs whereas for non-connected
0.18 m2/hrs.
Table-2 Time and Person for Retrofitting of Model House.
Model Name
Fully Connected
Non-connected

Time (hrs.)
20
14Work (per.)22Retrofitting (m2/hrs.)
0.13
0.18
per. - Working Persons
hrs. - Hours of Work

After the completion of retrofitting the houses was surfaced finished with mortar
cement, sand, lime ratio as (1:7.9:20) with w/c as 0.4 (water cement ratio) andcured for 7 days. Wooden roof connected after surface finishes was hardened.
5. EXPERIMENTAL SETUP & LOADING SEQUENCE.
To study the global and local behavior of building during shaking accelerometerand laser are used to record the acceleration and displacement for the test. There
were 24 one dimensional accelerometer attached to the specimen among which 13
in direction of shaking, 7 in transverse direction and 4 in vertical direction. There
were total 5 laser attached among which 3 for top wall displacement, 1 for midheight and 1 for base level. The experimental can be seen from Figure-7. The
measured data is recorded continuously at sample rate of 1/500 seconds in all the
runs.

a) Location of Accelerometer and Laserb) Actual Setup for Experiment

Figure-6 Experimental Setup for Shake Table test
Simple Sinusoidal motions with frequency ranging from 2 Hz to 35 Hz by varying
amplitude from 0.05 g to 1.4 g were applied to Model houses. The simple input
shall be used because for numerical simulation model house. Loading sequence874

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were given in the table-3 showing loading started from sweep motion and startingfrom 0.05 g amplitude varying frequency from 35 Hz to 2 Hz. The number ofcycles were constant for all frequency Amplitude from 1.0 g higher frequency
were ignored and lower frequency 5 Hz and 2 HZ have been used for testing. The
number described in the table is the run number for dynamic loading applied.
Table-3 Loading Sequence
Amplitude
Duration (sec)
1.2g
1.2g
1.0g
0.8g
0.6g
0.4g
0.2g
0.1g
0.05g
sweep

2Hz
20.00
54
50
48
47
46
18
10

5Hz
10.00
53
52
51
49
45
44
25
17
09

10Hz
8.00

Frequency
15Hz
20Hz
5.33
4.00

25Hz
3.20

30Hz
2.67

35Hz
2.28

43
42
41
24
16
08

40
39
38
23
15
07

34
33
32
21
13
05

31
30
29
20
12
04

28
27
26
19
11
03

01,02

37
36
35
22
14
06

6. CRACK PATTERNS FOR MODEL HOUSES.
URM house there were no crack before Run-26(35 Hz and 0.4g) and diagonal
cracks appear near openings and base of the house which further grows uponsuccessive runs. Diagonal cracks appear on all the side opening which become
prominent and visible after run 34(25 Hz and 0.8g). The cracks at the base areextend near diagonal cracks up-to Run-43(10 Hz and 0.8g). Furthermore,horizontal crack appear on the 6th layer from base and vertical crack extended
from base at the run. House was partially separated near the opening top andshowing large damage refer to figure-7 and finally house collapsed on run-44(5Hz and o.4g).

Figure-7 URM Run-43 (5 Hz & 0.8g)

of PP-bandmesh connectivity
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OptimizationOptimizationof PP-band Mesh
Connectivity
for Cost andforTime
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Fully connected PP-band house was not showing any significant damage before
Run-28 (35 Hz and 0.8g) but cracks from top around opening have initiated.
Small diagonal cracks appear after Run-32(25Hz and 0.4g) near openings. Run
37(20 Hz and 0.8g) there were diagonal cracks and horizontal crack at the base.
Diagonal have been extended to base cracks Run-41(10Hz and 0.4g) and fallingof plaster is also taking place. The cracks at this point were visible and prominent
on the house. At Run-45(5Hz and 0.6g) out of plane crack were observed andcondition of house was become worse. Run-51(5 Hz and 1.0g) the top part of near
the opening has been damaged and plaster has fallen as shown in figure-8.The PPband was broken at base and near openings, house is out of proportion. The Run54(2Hz and 1.2g) was last on which house collapsed by detaching of PP-bandfrom the base.

Figure-8 Fully Connected PP-band Run-51 (5 Hz & 1.0 g)
Non-connected PP-band house was not cracks before Run-27(35 Hz and 0.6g) andsmall cracks appear near the opening at this point. Run-28(35 Hz and 0.8 g)horizontal crack appear at the base. Cracks keep on extending near the opening for
Run-33(25 Hz and 0.6 g). At Run-39 (15Hz and 0.6 g) there were horizontal anddiagonal cracks on the house. Out of Plane cracks observed at Run-46(2 Hz and0.2g) for the house. The cracks are prominent and visible at the point this point
and plaster is falling from the crack parts of structure from the base. At Run52(5Hz and 1.2 g) the mostly house was damaged at the base and remaining
structure not showing damaged as shown in figure-9. The base suffered damaged
due to the connection of PP-band at the base only. The house collapsed at theRun-54(2Hz and 1.2 g) similar to the fully connected PP-band house.

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Figure-9 Non-Connected PP-band Run-52 (2 Hz & 1.2 g)
8. PERFORMANCE EVULATION.
Performance of the houses is evaluated on the basis of damaged level of thebuilding during the earthquake. Different level of damages as lightly damaged,
moderately damaged, partially collapsed, heavy damaged and collapse based on
the European Macro-seismic Scale, EMS-98 combining the JMA intensity for theapplied loading sequence.
URM has not shown any damage upto Run-25 (5 Hz and 0.2 g) and light structuredamages were observed at up to Run-31(30 Hz and 0.8 g). After Run-34 (25 Hz
and 0.8 g) diagonal cracks become prominent and visible and near Run-43(10 Hz
and 0.8 g) was partially collapsed corresponding JMA 4.The URM house wascollapsed at JMA5-. The performance of the URM can be seen from table-4
involving frequency and amplitude along with damaged category corresponding
to different colors referring JMA intensity.
Table-4 Performance of URM house model with different JMA intensities
Acceleration
(g)
1.4 g
1.2
1.0
0.8
0.6
0.4
0.2
0.1
0.05
Index

2

D0
D0

JMA 0~4

5

10

D5
D0
D0
D0

D4
D4
D4
D0
D0
D0

JMA 5-

DO: No damage
D1: Light Structure damage
D2: Moderate Structure damage

Frequency (Hz)15
20

JMA 5+

D3
D3
D3
D0
D0
D0

D3
D3
D3
D0
D0
D0
JMA 6-

25

30

35

D3
D2
D2
D0
D0
D0

D1
D1
D1
D0
D0
D0

D1
D1
D0
D0
D0
D0

JMA 6+JMA 7

D3: Heavy structure damage
D4: Partially Collapsed
D5: Collapsed.

of PP-bandmesh connectivity
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Connectivity
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Fully connected PP-band was damage up-to Run-27(35 Hz and 0.8g) but lightdamaged after that slight cracks at the top opening. The house was moderate
damaged up-to Run-43(10 Hz and 0.8g) equivalent to JMA 4 at which nonretrofitted house partially damaged at this stage. The structure showed partiallydamaged conditions which sustain large deformation and falling of plaster upto
JMA 6+ but can give time to evacuate the building. The house collapsed at JMA
7 of Run-54(2 Hz and 1.2g) sustain shaking and finally collapsed by breaking of
PP-band connection at the base. The performance of the PP-band fully connected
can be seen from table-5 involving frequency and amplitude along with damaged
category corresponding to different colors referring JMA intensity.
Non-connected PP-band has not shown any damage up-to Run-26(35 Hz and0.4g) and lightly damaged to Run-30 (30 Hz and 0.6g).The model shows was
Table-5 Performance of Fully connected PP-band retrofitted model
Acceleration
(g)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.1
0.05
Index

2

D3
D3
D3
D3
D0
D0

5
D4
D4
D4
D3
D3
D3
D0
D0
D0

JMA 0~4

JMA 5-

D5

10

D2
D2
D2
D0
D0
D0

DO: No damage
D1: Light Structure damage
D2: Moderate Structure damage

Frequency (Hz)
15
20

D2
D2
D2
D0
D0
D0

JMA 5+

D2
D2
D2
D0
D0
D0
JMA 6-

25

30

35

D2
D2
D2
D0
D0
D0

D1
D1
D1
D0
D0
D0

D1
D0
D0
D0
D0
D0

JMA 6+JMA 7

D3: Heavy structure damage
D4: Partially Collapsed
D5: Collapsed.

moderately damaged up-to Run-43(10 Hz and 0.8g) and performance of fully
connected and non-connected are in close relation to the one another and also
giving better performance than URM. The house has been partially damaged on
the JMA 6+ but collapsed at finally on Run-54(2 Hz and 1.2g) the base wasdamaged but has damaged but sustain almost same level of shaking to the fully
connected PP-band. The performance of Non-connected PP-band model can beseen from the table-6 involving frequency and amplitude along with damaged
category corresponding to different colors referring JMA intensity.
Table-6 Performance of Non-connected PP-band retrofitted model
Acceleration
(g)
1.4
1.2
1.0

878

2
D5

5
D4
D4
D4

10

Frequency (Hz)
15
20

25

30

35

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0.8
0.6
0.4
0.2
0.1
0.05
Index

D4
D3
D3
D3
D0
D0

D3
D3
D3
D0
D0
D0

JMA 0~4

JMA 5-

DO: No damage
D1: Light Structure damage
D2: Moderate Structure damage

D2
D2
D2
D0
D0
D0

D2
D2
D2
D0
D0
D0

JMA 5+

D2
D2
D2
D0
D0
D0
JMA 6-

D2
D2
D2
D0
D0
D0
JMA 6+

D1
D1
D1
D0
D0
D0

D1
D1
D0
D0
D0
D0
JMA 7

D3: Heavy structure damage
D4: Partially Collapsed
D5: Collapsed.

9. CONCLUSION:
The brick masonry single story house with similar construction technique for PPband retrofitting with fully connected and non-connected house have been made.
The study gives appropriate solution for retrofitting with PP-band by which we
can save the time and cost for house. URM house collapsed at JMA5- where as
both retrofitted house were collapsed at JMA 7 showing better performance
during sever ground shaking. Furthermore, retrofitted houses with fully connected
and non-connected PP-band collapsed at JMA 7.
Although the performance during the dynamic test for fully and zero connectivityof PP-band gives similar damaged but non-connected is more damaged at the base.
Thus life safety can be maintained with non-connected PP-band mesh and humancasualties can be achieved during sever ground shaking. Thus we can Suggest thatsingle story house having wooden Truss roof and surface finish can be retrofittedwith non-connected PP-band mesh giving optimum seismic retrofitting solution interm of cost and time.
REFERENCES:


Mayorca, P. and Meguro, K. (2004) Proposal of an Efficient Technique forRetrofitting Unreinforced Masonry Dwelling Proceedings on 13th World
Conference on Earthquake Engineering, Vancouver, CanadaSathiparan, N. and Meguro, K. (2012). “Seismic behaviour of low
earthquake-resistant arch shaped roof masonry houses retrofitted by PPband meshes.” ASCE Practice Periodical on Structural Design andConstruction. 17(2), 54-64.

Saleem M. Umair (2013) “Seismic Retrofitting of Masonry structure using
composite of Fibre Reinforced Polymer (FRP) and Polypropylene (PP)”
Ph.D. Thesis, University of Tokyo.

Grünthal, G., (ed.), (1998) "European Macro-seismic Scale 1998”, Volume
15, Luxembourg.

of PP-bandmesh connectivity
costEffectivenessand time effectiveness in seismic
OptimizationOptimizationof PP-band Mesh
Connectivity
for Cost andforTime
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Monitoring system for Nguyen Van Troi - Tran
Thi Ly stay cable bridge during construction
and for service stageNGUYEN Phuong Duy and TRAN Minh Phuong
VSL Vietnam Ltd.
duy.nguyenphuong@vsl.com
ABSTRACTThis paper briefly presents the monitoring system designed and installed for
Nguyen Van Troi – Tran Thi Ly stay cable bridge during the construction and forservice stage. Crossing the Han river in Da nang, Vietnam, the 731m long stay
cable bridge has a main span of 230m and an inclined pylon with one plan of stayin main span and the twisting arrangement of back stays anchored symmetricallyon each side of the bridge’s abutment. The monitoring system designed andinstalled on the bridge consists of stay cable loadcells, pylon inclinometer,
concrete temperature, concrete strain, wind intensity and direction. The
monitoring data allows controlling the strains and movements developed in the
structure in verifying with the design data. A portable accelerometer had beenused to control indirectly the cables tension using the vibrating wire theory. The
frequencies identified on the twisting back stay cables show a very good
harmonious between two symmetric plans proving the convenient of the method.
The cable tensions calculated through cable natural frequencies then comparewith the loadcells data and the lift-off jacking forces. In neglecting both sagextensibility and bending stiffness of the cables, a good correlation between liftoff jacking force, loadcells data and the tension forces calculated from cablefrequencies had been observed for medium and long cables.
Keywords: Stay cable bridge, monitoring system, cable tension, cable vibration
1. INTRODUCTION
For modern bridge maintenance and management, a reliable monitoring system isof central important. The major objective of bridge monitoring system is toprovide controls during construction stages but also to identify damages ordeteriorations during exploitation.
Crossing the Han River, connecting the Hai Chau and Son Tra districts in Da
Nang city, the new Nguyen Van Troi – Tran Thi Ly stay cable bridge is designed
as a symbol of the beach and port city in the middle of Vietnam. The 12 degrees
inclined pylon rising 145m height from the water level can be observed from any
location of the city. The pylon supports one main span stay cable and twist
symmetric back stay cable plans forming an interesting aesthetic aspect viewing
from all direction.

881

October
2013, 2013,
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Vietnam0ctober
VietnamComplicated structure and construction method raise the need to design and installa structural monitoring system for surveying the structural responses during theconstruction period but also extendable for bridge health monitoring during theservice stage.

Figure 1: Nguyen Van Troi – Tran Thi Ly stay cable bridge
2. MONITORING SYSTEM REQUIREMENT
The design and installation of the monitoring system of Nguyen Van Troi – Tran
Thi Ly bridge are for the following purposes:
 Providing the data for structural analysis and state asses through thestructural response and behavior during the construction stages likestresses, deformation, temperature variation, tension and vibration of stay
cable, pylon movement.
 Design verification by checking the design assumption to monitoring datasuch as wind direction and intensity, structural and ambient temperature
variation, effect of gradient temperature of the bridge during the different
construction stages. The stresses in the critical section are also assessed fordesign verification and construction control.
 For the service stage, the monitoring data is employed for assessing extent
of damage/deterioration, evaluating the structural performance, response
to unexpected accident or managing the traffic and bridge’s normal
operations.
3. MONITORING SYSTEM DESIGN AND DATA ASSESMENT
The structural monitoring system for Nguyen Van Troi – Tran Thi Ly stay cablebridge consists of:882

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







Monitoring the stresses variation in the critical section of concrete pylon
and girder for the construction survey;
Measuring and survey the movement of pylon during construction stages;
Monitoring the temperature in the pylon, girder and stay cable;
Monitoring wind intensity and direction;
Measuring and monitoring the tensile forces on the stay cables by using a
combination method (loadcells and vibration measurement);
Vibration monitoring of the cables, girder and pylon by using the portableaccelerator system;
At the end of the construction period, a 3D movement monitoring systemusing the GNSS technology had been installed at the pylon top.

Figure 2: Data acquisition and analysis software interface
All the monitoring equipments have been configured to the data acquisition
system and then transferring the data to the central computer installed on thebridge deck level assuring the continual data recorded and assessment. A dataacquisition software had been developed specifically for Nguyen Van Troi – Tran
Thi Ly bridge. The main function of the software is to acquire, record, analysis
but also controlling the system and warning any measurement value reaching thecritical range. The system is also designed to be able to extent for future needs.
4. CONCRETE STRESSES AND TEMPERATURE MONITORING
During the construction stages, stresses and temperature state in the concretepylon and girder had been closely monitored and the data had been recorded forcontrolling the bridge structural response. The figure 3 shows the stresses state
recorded for the period of September 2012 at pylon section PYS20. A goodcorrelation between the measurement points on the section had been observed.
Monitoring
systemVan
for Nguyen
Van– TranThi bridge
Ly stayduringcable bridge
duringMonitoring system
for Nguyen
Troi -Tran
ThiTroi
Ly stay
cable
construction
construction
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and for service stage883

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The stresses monitoring data allows to survey the construction method bycomparing with the design values.

Figure 3: Pylon Stresses state monitoring data
5. STAY CABLE TENSILE FORCES MONITORING
Around the world and in Vietnam, there exist several techniques to assess thetensile forces in the stay cable. They are namely measurement of the force in atensioning jack (lift-off), application of ring loadcell, topographic survey andelongation of the cable during tensioning and installation. In spite of their simple
theoretical description, the practical application is highly complex and not always
economically effective, accuracy or even applicable (Casas, 1994). A relatively
simple, quick and inexpensive method of measuring cable forces in cable staybridge is to use the vibrating wire theory in basing on the cable natural frequency(f), the mass (m) and the real length (L) by using the following formula:T = 4mf2L2(1)

This method had been successfully applied around the world to relatively shortstay cable bridge cables with simple anchoring devices as well as to external prestressing cable (Demars and al., 1985). However, if the vibrating wire theory isapplicable for determining the stay cable tensile forces, there is a linear
correspondence between vibration modes and natural frequencies. The main
assumptions of the theory are:
 The cable has a negligible flexural stiffness;
 There is no relative displacement of the point where the cable is anchored; The cable is inextensible. The transverse deflection of symmetrical modes
does not generate additional tension in the cable.
For much longer stay cable length or the complicated anchorage devices, deviator,
dumper, the determination accurately of the real vibrating length of the cable

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becoming very difficult (Kiska and al., 1991). On another hand, the actual
vibrating behavior maybe deviated substantially from the vibrating wire theory.
The determination of the lowest natural frequencies may have a big dispersion andthen effect on the tensile force calculation (Robert and al., 1991)
Different methodology had been proposed in that circumstance to obtain accurate
results of the stay cable tensile forces. The simplest one is to combine
measurement techniques which compensates for the errors of one method with theresults of another using the least-square minimization procedure. Morecomplicated methodologies consists of taking into consideration the effect of stay
cable flexural stiffness or extensible of the cable.
For measuring and monitoring the stay cable tensile force of the Nguyen Van Troi
– Tran Thi Ly bridge, we adopted a combining method. The tensile forces were
measuring by the vibration method in identifying the natural frequencies andindirectly calculated the forces. The results were then verified and calibrated bycomparing with the monitoring data from seven loadcells pre-installed on thecables anchorages and the direct measurement of lift-off data.
The cable forces in cable stay is then calculated by using the following formula(Cunha and al., 1995):
T = 4mfn2L2/(n2g)(2)

where T is the tensile force in the stay cable, fn is the nth natural frequency, L isthe distance between two fixed ends of the cable and m is the mass of the cable
per unit length.

Figure 4: good harmonious frequencies between two symmetric plans of back stay
The natural frequencies identified on the twisting back stay cables at the end of
construction are presented in the figure 4 and show a very good harmonious
between two symmetric plans proving the convenient of the measurement method.
Monitoring
systemVan
for Nguyen
Van– TranThi bridge
Ly stayduringcable bridge
duringMonitoring system
for Nguyen
Troi -Tran
ThiTroi
Ly stay
cable
construction
construction
andforservicestage
and for service stage885

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Vietnam

The calculated tensile forces are then compared with the lift-off data and thereading value from pre-installed loadcells for verifying the efficiency of themethod (VSL VN, 2012). The figure 5 shows the tensile forces error between the
direct lift-off measurement data and the indirect result using the vibrating wirecalculation theory. In neglecting both sag-extensibility and bending stiffness ofthe cables, a good correlation between lift-off jacking force, loadcells data and thetension forces calculated from cable frequencies had been observed for both
symmetric back stay cables. A maximum error of 4% is recorded for all back stay
cables. Same error range had been recorded in comparing the calculated forces
with the loadcell reading values.

Figure 5: Error of the tensile forces between the direct and indirect method (twist
plan of back stay 15 nos. each)
6. PYLON MOVEMENT MONITORING BY GNSS TECHNOLOGY
To manage bridges effectively, more needs to be done to access the day-to-day
and long-term condition and behavior of in-service bridges, so that preventive
measures can be taken, and deterioration rates can be better understood. Owning
the advantages of high accuracy, all-weather condition and no requirements ofinter-visibility between measuring points, the GNSS technology suits well thismonitoring purpose fulfilling both static and dynamic measurement needs. This
technology had been applied for the Nguyen Van Troi – Tran Thi Ly stay cablebridge for permanent 3D pylon movement monitoring.
The small network of GPS reference stations can be used very effectively formonitoring deformations and movements of man-made structures. For bridge
structural monitoring, in order to monitor rapid, short-term movement and evenvibrations, the raw data have to be streamed continuously at a high rate from thereceivers to the control computer processes the baselines between the stations
continuously. A software component running on the server can compute the886

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baselines of the network continuously or at regular intervals to determine thepositions (coordinates) of the monitoring points.

Figure 6: Rover antennas on top pylon and base station installation
For the bridge monitoring, reliable communication is vital for the efficient
operation of GPS reference station and networks of stations. The reference station
software running on the server has to control the receivers and download the data.
In Nguyen Van Troi – Tran Thi Ly bridge, an optical fiber network had been
adopted for RTK data transfer from base station and rover stations to the centralcomputer. The figure 6 shows the reference station and the rover antenna installedon the top of pylon for permanent movement monitoring.

Figure 7: Real time movement of the top of pylon
Monitoring
systemVan
for Nguyen
Van– TranThi bridge
Ly stayduringcable bridge
duringMonitoring system
for Nguyen
Troi -Tran
ThiTroi
Ly stay
cable
construction
construction
andforservicestage
and for service stage887

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Vietnam

The movement of the pylon had been calculated and an example of movement
recording and displaying is showed on the figure 7.
7. CONCLUSION
The demand for bridge structural health monitoring is continually increased asengineers are continually challenged to provide and maintain a safe and efficienthighway network. Considering as the only method to help engineer to understandcompletely the condition and behavior of the bridge structures, the structuralmonitoring is also considering as a traffic management strategy aids tool. The
paper presents a monitoring system successfully designed and installed for
Nguyen Van Troi – Tran Thi Ly stay cable bridge for construction survey andservice stage assessment. The application of vibration method for measuring thestay cables forces proved the efficiency, the error recorded are less than 4% for allback stay cables in comparing with the lift-off data and loadcells monitoring data.
The monitoring system is also proving the efficiency of the application of the
GNSS technology for 3D pylon movement monitoring.
REFERENCES
Cunha, A. and Ceatano, E., 1997. “Dynamic measurements on stay cable of cablestayed bridges using an interferometry laser system”. Experimental Technique,23(3): 38-43.
Casas, J-M., 1994. “A combined method for measuring cable forces: the cablestayed Alamillo Bridge, Spain”. Structural Engineering International, Journal of
the IABSE, Vol.4, No.4, pp.235-240.
De Mars, P.: Hardy, D., 1985. “Mesure des efforts dans les structures a cables”.
Annales TP Belgique 6. Bruxelles. 1985, pp. 515-531.
Kyska, R.; Koutny, V.; Rosko, P., 1991. “Tension Measurement in Cables ofCable-Stayed Bridges and in Free Cables”. Proc. Of the Second Conf. on Traffic
Effects on Structures and Environment, Zilina, Slovakia, April 1991. pp. 190-194.
Irvine H.M., 1981. Cable Structures. MIT Press, 1981.
Robert, J.L.; Bruhat, D.; Gervais, J. P., 1991. “Mesure de la tension des cables par
méthode vibratoire”. Bulletin de Liaison des Laboratoires des Ponts et Chaussées,173. Paris, 1991, pp. 109-114.
VSL VN, 2012. “Report for Tensile forces measurement using vibration method
on 12th Sept 2012”. Nguyen Van Troi – Tran Thi Ly bridge project, Da Nang.
Leica Geosystems, 2010. “GPS Reference Station and Networks – Anintroductory Guide”.

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Practical evaluation method ofcollapse limit displacement based onseismic damage of structural members
Kazuto MATSUKAWA1 and Masaki MAEDA2
1
Research Associate, IIS, The University of Tokyo, Japan
mtkw@iis.u-tokyo.ac.jp
2
Professor, Dept. of Architecture and Building Science, Tohoku University, Japan
ABSTRACT
Authors proposed an evaluation method of collapse limit displacement of RC
structures based on its capacity curve and seismic response spectrum in past
papers. In this paper, referring the method, more practical method to evaluate
collapse limit displacement based on damaged members ratio (DMR) was
developed. The DMR is briefly explained as ratio of number of severe damaged
members and number of total members in a structure. Correlation of DMR andcollapse limit displacement which calculated by proposed method in past papers
was investigated by nonlinear static analysis for 20types of RC frame. At result,on average, these buildings suffered damage of DMR of 0.2 has 5% probability ofcollapse risk. This correlation was also investigated its validness by statisticalanalysis using a database of actual damaged buildings due to past earthquakes
such as Tohoku EQ.2011, Kobe EQ.1995 and more. At result, it is found thatdamaged buildings less than DMR of 0.3 could avoid collapse in the earthquakes,
therefore, a criteria for collapse prevention found in frame analysis mentioned
above, DMR of 0.2 was conservative for the result of the statistical analysis.
DMR is index which is easy to calculate from result of frame analysis, therefore,
structural engineers may be able to calculate collapse limit displacement
practically by referring DMR of 0.2.
Keywords: collapse assessment, shear failure
1. INTRODUCTION
Due to huge earthquake, reinforced concrete structures might have collapse riskby shear failure of members. Shear failure may cause a total collapse of buildings
because of rapid degradation of horizontal and axial capacity. In Japanese seismiccode and design standards (AIJ.2004), such behavior in shear resistance has notbeen considered because of its complexity and unclearness. Therefore, safety limit
state of buildings (maximum displacement point of buildings to prevent collapse)
is generally taken at the first occurrence of shear failure of a structural member
and it is often conservative comparing with actual collapse limit.
In addition, to know the collapse limit displacement is important because
structural engineers will be possible to show the actual capacity of buildings to889

October
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Hanoi,Hanoi,
Vietnam0ctober
Vietnamowners. Therefore, collapse risk assessment has been a significant research topic
and many kinds of research regarding collapse assessment were carried out.
Haselton et.al (2011), the one of examples, are assessed collapse risk of buildings
designed by referring ASCE 7 (ASCE 2002, 2005) and ACI 318 standards using
Incremental Dynamic Analysis method (IDA method). In the IDA method, aground motions were increasingly scaled and input until building collapse.
However, IDA method requires extensive technical knowledge, high experienceand lots of time to structural engineer, therefore, it may be difficult to use instructural design.
The authors proposed a method to evaluate collapse limit based on Capacity
Spectrum Method (CSM) as a more practical method than IDA method(Matsukawa and Maeda, 2013). The accuracy of collapse limit displacement
calculation by the CSM method was investigated by comparison with collapse
limit displacement calculated IDA method using SDOF system. The results
showed that collapse limit displacement by the CSM method corresponds withcollapse limit displacement calculated by IDA method with errors within plus orminus 20 percent.
In this paper, relation of collapse displacement and damage of structural members
was investigated by nonlinear frame analyses for several kinds of structures andby statistical analysis using database of actual damaged buildings. The aim of thisresearch is to develop a more practical method to evaluate collapse limit
displacement based on damages of structural members. The method will enable toevaluate collapse limit displacement without special computer analysis (by only
static analysis) for structural engineers. And the method is also expected todevelop more to apply in evaluation of residual seismic capacity of damagedbuildings.
2. EXPLANATION ABOUT COLLAPSE LIMIT EVALUATION METHODBASED CAPACITY SPECTRUM METHOD
2.1 Basic Methodology
In this chapter, evaluation method of collapse limit point against side-sway
collapse (collapse when lateral displacement of building increase without bounds)
based on CSM proposed in past paper (Matsukawa and Maeda, 2012) is explained.
Key features of which are briefly summarized as follows:1)
Calculate Seismic Capacity Index (SCI) for equivalent SDOF system whichis converted from frame model using results of its nonlinear static frame
analysis.
2)
Take the maximum SCI point of equivalent SDOF system as collapse limit.
SCI (Architectural Institute of Japan, 2004) is the ratio of ultimate spectral
acceleration at each response point and standard spectral acceleration (5%damping) at period of the point as shown in Figure1, therefore, increment of SCI
will roughly correspond with amplitude scale when IDA was carried out (seeFigure2). As mentioned above, the maximum SCI point is taken as the collapse
limit displacement in this method because that point means the maximum
response point that building can prevent collapse when the maximum resistible
scaled ground motion suffered.

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The conceptual drawings about this method are shown in Figure3 (a)-(c).
Response point will be found if ground motion (response spectrum) is muchsmaller than building capacity as shown in Figure3 (a). When larger groundmotion suffered, response point will move and will get closer to the collapse
displacement, then the response displacement reaches collapse displacement whenultimate ground motion that building prevent collapse was suffered (see Figure3(b)). If spectral acceleration becomes larger or more, response point will not befound and building will collapse as shown in Figure 3 (c).
Spectral Acc.

IDA Method
LS: Strength of Standard Spectrum

SCI=LU/LSStandard Spectrum (5% Damping)

SCR
Amplitude Scale

LU: Strength of Ultimate Spectrumof Point A

Maximum amplitude scale where
dynamic instability is not occurred

Ultimate Spectrum at PointA(5% Damping)

Collapse Limit
Maximum Response(each Method)
Displacement
A Max. response disp. when each scaled ground motion
inputted

Building Capacity
Curve

Spectral Disp.

Figure : 1 General concept of SCI

Spectral Acc.

Spectral Acc.

Response Point

Spectral Disp.

Figure 2 : Relation of SCI and amplitude
scale of IDA

Ultimate Displacement where
Response Point could be found .
Collapse Limit

Spectral Disp.

Spectral Acc.

A

Building Capacity CurveSCINo Response Point
Collapse

Spectral Disp.

(a)
(b)
(c)
Figure 3 : Examples for relations of response spectrum and collapse
2.2 Analytical Models and Methodologies

2.2.1 Basic Models
Analytical models and methodologies are explained in this section to display
calculation examples of the method mentioned above (and the results will be usedin development more practical method based on damage of structural members in
next chapter). The models of this research are 3stories and 6stories building
models which have 4 bays and half beam with a roller support at both left andright side of each building model. Unit weight of each floor is assumed as
12kN/m2. Drawing of basic modeling of the structures is shown in Figure4.
Members composing each structure were converted as rod element models whichhave axial, shear and flexural spring, in addition, rigid zones exists at both end of
the rod elements. As shown in Figure4, structures planed so that collapse by 1ststory collapse mechanism will occur, therefore, elastic springs are applied foreach spring of all members except for columns at 1st story. In addition, columns of
1st story are named from left to right as “Column A” to “Column E” (see Figure4).

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evaluation
methodlimitof collapse
limit displacement
based on seismic damage ofPractical evaluationof collapse
displacement
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on seismic damage of structural members

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2.2.2 Characteristics of Structures and Members
Columns at 1st story are applied several types of characteristics; F2, F3, F4, S3
and S6. Column characteristics named as F2, F3 and F4 are for flexural members
and numbers after “F” means μfu which is mentioned later. Flexural members
consist of an elastic shear spring, an elastic axial spring and inelastic flexuralsprings. 4-linear model is applied to the inelastic flexural springs and capacity
degradation curve was assumed as strength reaches to 0kN when μ (plastic ratio:
displacement divided by yield displacement) equal to μfu+2 (μfu: plastic ratio at
capacity degradation start).
Unit:mm
500

Column

3,675

8,000

8,000

Dc/4

8,000

Shear
SpringAxial
SpringDb/4

Flexure Spring

Column Model

Dc

3,500
8,000

700

3,675

4,000

Column

Beam

3,675

×

700

Beam

3,675

Beam Model

700

Node

3,675

×

4,000

ColumnColumnColumnColumnColumn
C
D
A
E
B

3stories4bays(1st story collapse)
6stories4bays (1st story collapse)

Figure 4 : Drawing of structure models and basic modeling of members
800

600
500
400
300

1000

600
400

100

200
0

50

100

150

Shear Spring Deformation(mm)

200

F2
F3
F4

800

200

0

Plastic ratio: μfu

1200
Moment(kNm)

Shear Force(kN)

1400

S6
S3

700

0
0.00

μfu+2

0.01 0.02 0.03 0.04
Rotation Angle(rad.)0.05

Figure 5 : Backbone characteristics of inelastic shear and flexural springs(for 3stories models)

ColumnA
ColumnB
ColumnC
ColumnD
ColumnE

Table1 : Application of column for each type of models
type1 type2 type3 type4 type5 type6 type7 type8 type9 type10
F3
F3
F3
F3
F4
F4
F4
F4
F2
F4
F2
S3
F2
S6
F3
S3
F3
S6
F2
F4
S3
F2
S6
F2
S3
F3
S6
F3
S3
S3
F2
S3
F2
S6
F3
S3
F3
S6
F2
F4
F3
F3
F3
F3
F4
F4
F4
F4
F2
F4

Column characteristics S3 and S6 are for shear members, “3” and “6” are drift
angle that strength reaches 0kN due to capacity degradation. Shear members haveelastic flexural springs, an inelastic shear spring and an elastic axial spring. 4-892

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linear model is applied to the inelastic shear spring. Inelastic shear springs andflexural springs used in the analysis are shown in Figure5. Maximum strength ofthese inelastic springs is decided so that maximum strength summation of all 1ststory columns corresponds 50% of total weight.
10 series of column type combination for each 3 and 6 story models are used inparametric study mentioned in next section. Table1 shows the combination, they
are chosen so that many types of capacity curve will be obtained.
2.2.3 Analytical Procedure
Nonlinear static analysis (displacement-controlled pushover) was carried out sothat displacement of each story at each analytical steps corresponds 1st vibration
mode shape. After that, equivalent capacity curve was obtained by converting
story shear –drift curve using EQ.(1) and (2).

S a  QB m    m   
j

j

j

j

2

(1)

2

Sd 

 m    m   
j

j

j

2

(2)

j

Where; Sa : spectral acceleration, Sd : spectral displacement, QB : base shear, mj :mass at jth floor, δj : jth floor displacement from base.
12 observed ground motions in past earthquakes which consists of Elcentro 1940
wave (EW, NS), Kobe 1995 wave (EW, NS), Hachinohe 1968 (EW, NS), Ojiya
2004 (EW, NS) , Tohoku 1978 (EW, NS), Taft 1952 (EW,NS) were used to
calculate response spectrum and were applied in collapse assessment. In addition,
three response spectrums referred from Japanese Building Code (JBC, see
Figure6 ) assuming each soil type as soil-type1 (solid), soil-type2 (Moderate) soiltype3 (soft) were also applied in this analysis.
Each model was evaluated collapse limit displacement for each response spectrumby the method explained in section 2.1. The number of combinations was 20(types of 3 and 6 stories building) x 15 (Observed spectrum:12, JBC spectrum:3)
equal to 300.

Spectrum Accelaration(gal)1400

JBC soil-type1
JBC soil-type2
JBC soil-type3

1200
1000
800
600
400
200
0

0

0.5

1

1.5
Period(sec)

2

2.5

3

Figure 6 : Seismic response spectrum referred from JBC
In addition, dumping of each model is evaluated as weighted average dumping ofeach spring which is summation of viscous dumping (assuming 5% of initial

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evaluation
methodlimitof collapse
limit displacement
based on seismic damage ofPractical evaluationof collapse
displacement
based
structuralmembers
on seismic damage of structural members

893

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Vietnam0ctober
Vietnamviscous dumping) and hysteresis dumping. Hysteresis dumping of each inelastic
spring is calculated by energy absorption and potential energy on hysteresis loop.
2.4 Analytical Result
2.4.1 Pushover Analysis
Examples of Pushover results are shown in Figure7. As mentioned above, firststory collapse mechanism was generated in all cases.
2.4.2 Capacity curve of converted SDOF system and collapse limit
Figure8 shows examples of the calculation results for capacity curve of each
equivalent SDOF system converted from the results of Pushover analysis by
EQ.(1) and (2). Evaluated collapse limit points are also displayed in Figure8.
Collapse limit points for JBC spectrum are conservative for results using response
spectrum calculated by ground motion in past earthquake.
3F-type1

0.45

1st story

0.35

3rd story

0.3

1st story

0.4

2nd story
Story Shear Coefficient

Story Shear Coefficient

0.4

3F-type2

0.45

0.25
0.2
0.15
0.1
0.05

2nd story

0.35

3rd story

0.3
0.25
0.2
0.15
0.1
0.05

0

0

1

2
3
Story Drift Angle (%)

4

0

0

1
2
3
Story Drift Angle (%)

4Spectral Acceraration(gal)Figure 7 : Results of Pushover analysis (3stories model type1 and 2)
1000
900
800
700
600
500
400
300
200
100
0

0.5sec3F-type2

0.5sec1.0sec1.0sec

0

0.05
0.1
0.15
0.2 0
Spectral Displacement(m)Capacity Curve

6F-type2

0.05
0.1
0.15
0.2
Spectral Displacement(m)Collapse Limit(Obserbed)

Collapse Limit(JBC)Figure 8 : Results of collapse assessment (3 and 6 stories model type2)894

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3. COLLAPSE LIMIT DISPLACEMENT AND DAMAGED MEMBERS
RATIO
3.1 General Concept for relation of DMR and Collapse Limit Displacement
In this chapter, relation of structural damage of members in static analysis
mentioned above and collapse limit displacement calculated previous chapter isinvestigated. A index of structural damage of members is called as Damaged
Members Ratio (DMR) and is defined as Eq.(3) and (4).
m

DMR   i
i 1

(3)

i 

 i  K deg,i
m

K
i 1

(4)

deg,i

Where; λi : contribution factor showing that capacity degradation at plastic hinges
and shear critical member (these are counted as damage part i) contribute capacity
degradation of capacity curve of overall building, αi : effectiveness factor; 0.5 forplastic hinges, 1.0 for shear critical members (these values are assumed in thispaper and furthermore studies are needed to determine suitable values), Kdeg,i :
slope of capacity degradation curve of damage part i.
DMR is plainly explained as a weighted average of capacity degradation curve ofeach damage part Kdeg,i, because past research (Matsukawa and Maeda, 2013)
showed that collapse limit is dominantly decided by capacity degradation curve of
equivalent SDOF system and response spectrum shape. DMR is used incorrelation analysis to evaluate lower boundary (5% probability of collapse) of
collapse limit as shown in Figure9.
From results for 240 of parametric analysis mentioned in previous chapter(analyses of JBC spectrum were omitted), DMR at collapse limit displacement foreach model and each response spectrum were obtained. Figure10 shows one ofcalculation examples of DMR at every analytical step calculated based on
pushover analysis mentioned in previous chapter and DMR at collapse limit ismarked.
After that, cumulative frequency distribution curve that demonstrates cumulative
frequency of collapse risk by DMR at collapse limit is constructed assuming it
obeys beta distribution. As the result shown in Figure11, it is found that 5%
probability of collapse corresponds 0.20 of DMR, in other words, buildings
suffered damage equal to DMR of 0.2 have 5% of collapse risk. Althoughreferring this curve enables to assess collapse risk from DMR as mentioned above
and shown in Figure9, models or response spectrum used in this paper may havesome bias, therefore, another approach is taken in this chapter using actual
damaged building data.

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evaluation
methodlimitof collapse
limit displacement
based on seismic damage ofPractical evaluationof collapse
displacement
based
structuralmembers
on seismic damage of structural members

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VietnamParametric Analysis for Correlation of DMR and Collapse Limit
DMR

ModelA, Response SpectrumX

ModelC, Response SpectrumZ

ModelB, Response SpectrumY

0.6

0.5

・・・

0.3

Displacement

Displacement

Displacement

Collapse Limit

cumulative frequency distribution

DMR and Collapse Limit are calculated for 20Models x 12Ground Motions

Probability distribution of
DMR when Model Collapse

Criteria f(DMR)=5%
Ex)0.2

DMR when Model Collapse

1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0.00

type1

1
0.9

0.05
0.10
0.15
0.20
Spectral Displacement(m)6stories
00.00Limit(JBC)0.05
Collapse

3stories
0.10 Collapse
0.15
0.20
Limit(JBC)Collapse Limit(Observed)Sd[m] Collapse Limit(Observed)

Figure 10 : Examples of DMR

Cumulative Frequency
Distribution

DMR

Figure 9 Conceptual drawing of DMR and collapse risk

0.8
0.7
0.6
0.5

50%

0.4
0.3
0.2
0.1
0

5%

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
DMR (at collapse limit)
Ave.=0.82,σ=0.24

Figure 11 : Cumulative Frequency of DMR

3.2 Database of Damaged Buildings during Past Earthquake
The database was constructed from data of damaged Japanese RC schoolbuildings in past earthquakes (e.g. Southern Hyogo Earthquake 1995, Mid-Niigata
Earthquake 2004, Iwate-Miyagi Earthquake 2008 and Tohoku Earthquake 2011).
Basic characteristics of the database components are shown in Figure12. In
addition, the database consists of buildings classified damage level “heavy” and“collapse”.
In the database, damage class of each member inspected by the researchers arerecorded and the damage class relates maximum response of members as shownin Figure13 (JBDPA, 2001).

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IwateMiyagi
Nairiku
EQ.20082%

19813%
19711981
27%

606%

Tohoku
2011
19%

-1971
70%

Mid
Niigata
2004
4%

-30
30%

30-60
64%

Southern
Hyogo 1995
75%

Construction
Year

Earthquake Buildings
Suffered

Residual Seismic Capacity(%)

Figure 12 : Component ratios of the database
3.3 DMR at collapse limit
Relation of DMR and building damage level is shown in Figure14. The horizontal
axis named as “Residual Seismic Capacity” is calculated capacity of damaged
structures referring JBDPA Guideline (JBDPA, 2001). As shown in Figure14,
collapsed buildings are pointed at region of DMR > 0.3 and the buildings pointed
DMR < 0.3 could avoid collapse (although suffering “heavy” damage was notable to avoid).
From result mentioned previous section, 5% probability of collapse corresponded
DMR of 0.2, therefore, the probability was conservative for analysis in thissection.
Figure15 shows cumulative frequency distribution of both computational analysis
and actual damage data. Computational curve calculated in chapter2 corresponds
actual curve at DMR of lower value (DMR < 0.25) region and is conservative at
DMR of higher value (DMR > 0.25) region. From these analyses, buildings
possibly avoid collapse at displacement that DMR less than 0.2 althoughfurthermore studies are needed.

Ⅳ

Ⅴ

Ⅰ

Ⅱ

Ⅲ

Ⅳ

Ⅴ

Shear ForceShear Force

Ⅰ-Ⅲ

Displacement

Displacement

Figure 13 : Damage classification of shear (left) and flexural (right) members

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evaluation
methodlimitof collapse
limit displacement
based on seismic damage ofPractical evaluationof collapse
displacement
based
structuralmembers
on seismic damage of structural members

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VietnamCollapse
heavy

0.9
0.8
0.7

DMR

0.6
0.5
0.4
0.3
0.2
0.1
0.0

0

10

20 30 40 50 60 70
Residual Seismic Capacity(%)

Figure14 DMR and actual damage

Cumulative Frequency Distribution

1

1.0

0.9
0.8
0.7
0.6

Database
ave:0.66
σ:0.23

0.5
0.4
0.3
0.2
0.1
0

chapter2
5%0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

DMR of Collapse Buildings

Figure15 Collapse risk based on DMR

4. CON CLUSION REMARKS
Contributions of this paper are shown in as follows;
1) Based on seismic response spectrum and capacity curve of models, evaluation
methodology of collapse limit was explained. The method is practical approach toassess building collapse and assessment examples of 3 or 6 stories buildings wereshown.
2) Damaged Members Ratio, the index of damage to structure was proposed.
From pushover analysis of building models and statistical analysis of actual
damaged building data, it is found that RC structures possibly can avoid collapse
if structures suffered damage of DMR less than 0.2.
REFERENCES
Haselton, C. B., Liel, A. B. and Deierlein, G.G., 2011. Seismic Collapse Safety ofReinforced Concrete Buildings. I: Assessment of Ductile Moment Frames.
Journal of Structural Engineering. 481-491.
Matsukawa, K. and Maeda, M. 2013. Methodology to Evaluate Collapse Limit
State of R/C Frame Based on Seismic Response Spectrum, Journal of Structural
And Construction Engineering. Architectural Institute of Japan. No.693. (NotPublished but Accepted)
Architectural Institute of Japan, 2004. Performance Evaluation of Earthquake
Resistant Reinforced Concrete Buildings (Draft) (in Japanese), Japan
Japan Building Disaster Prevention Association, 2001. Guidelines for Postearthquake Damage Level Classification of Reinforced Concrete Building. Japan

898

New Technologies
for Urban
Safetyof Mega
New Technologies
for Urban Safetyof Mega
Citiesin AsiaCities in Asia

Ultra high performance concrete
using a combinationof silicafume and limestone in Vietnam
Nguyen Cong Thang 1, Nguyen Van Tuan1, Pham Huu Hanh 1
1

Department of Building Materials, National University of Civil Engineering,
55 Giai Phong Road, Hanoi, Vietnam

ABSTRACTUltra-High Performance Concrete (UHPC) is considered to be one of major
breakthroughs in concrete technology with superior quality, especiallycompressive strength greater than 150 MPa, high fluidity and durability
properties. This opens a door for some new and very potential applications inconstruction industry such as thin shell structures, high rise-buildings, long spanbridges, and construction in aggressive environments.
Regarding the material components, in general, a very high mount of cement,
about 900-1000 kg/m3 used to produce UHPC, will cause some disadvantages
from the point of view of sustainable development. The use of mineral admixtures
to replace cement is one of good ways to overcome this problem.
This paper presents the preliminary results of using a combination of silica fumeand limestone powder in Vietnam as cement replacement material in making
UHPC. The results show that this combination improves both the flow slump andcompressive strength of UHPC. Additionally, a maximum amount of total cement
replacement by this combination is also considered in this study. This is very
important for the sustainable development of the construction industry.
1. INTRODUCTION
Ultra High Performance Concrete (UHPC) is a new class of concrete with highfluidity, high strength (over 150MPa), high flexual strength (using fiber), lowpermeability and high durability (AFGC-SETRA, 2002, Buitelaar, 2004). UHPC
has been gained a strong interest in research and development from the early
1980s. Up to now, some potential applications of UHPC can be seen such as
elements, girders, deck slabs, silos, etc in precast or repairing structures, ormaking columns with high load, nuclear waste tanks, etc.
UHPC, in general, is composed of cement, silica fume, quart sand (100-600µm)
instead of the ordinary aggregate, water and superplasticizer. The high amount of
cement in UHPC, about 900-1000 kg/m3 (Richard and Cheyrezy, 1994) , ingeneral, which impacts on global environment (Vooa and Fosterb, 2010, Turgut,2007). Therefore, the use of the mineral admixture to replace cement in producing
UHPC is feasible both technically, environmentally and economically.

899

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnam

In fact,some mineral admixtures such as ground granulated blast-furnace slag
(GGBS), fly ash (FA), Metakaolin, Limestone (LS) have been being used to makenormal concrete and even UHPCetc. Among these admixtures, LS is considered
as a potential admixture in making UHPC with some advantages (Turgut, 2007,
Heikal et al., 2000), i.e. not only reducing cost of UHPC production but also
decreasing amount of cement which result in reducing the CO2 emission and theuse of natural resources. In addition, the finer limestone can improve the packing
density of system and can densify the transition zone between cement paste andaggregates. The addition of limestone will improve workability of UHPC
mixtures and help to disperse cement particles and to enhance the crystalline
nucleation, thus promote the hydration of cement and increase compressive
strength of UHPC.
This paper presents the exprimental results of using limestone in combination
with or without silica fume on properties of UHPC at difference curing regimes.
The limestone replacement content is studied from 5 to 20% by weight of binder(cement, silica fume and limestone). Two curing conditions, normal treatment(27±2oC, RH>95%) and heat treatment (90±5oC, RH>95%), are considered in thisstudy.
2. MATERIALS AND METHODS
2.1 Materials
The materials used in this study were Portland cement PC40 (according toVietnamese standard) with particle size of 14μm, condensed silica fume (SF),limestone (LS), and polycarboxylate based superplasticizer with 30% solid
content by weight. The SF has an amorphous SiO2 content of 92.3% and its mean
particle size is about 0.15μm. The particle size distribution and the mean particle
size of materials in this study were determined by laser diffraction. Quart sandwith a particle size of 600μm. Limestone (LS) with a particle size of 5μm. Oxide
compositions of the cement, silica fume and limestone used in this study are
shown in Table 1. The particle size distribution of these materials is shown in
Figure 1.
Table 1. The chemical composition of limestone, Cement and Silica fume

900

No

Chemicalproperties

Units

1
2
3
4
5
6
7
8
9

SiO2
Fe2O3
Al2O3
CaO
MgO
Na2O
K2O
SO3
LOI

%
%
%
%
%
%
%
%
%

Contents, %Cement

SF

LS

20.30
5.05
3.51
62.81
3.02
2.00
1.41

92.3
1.91
0.86
0.32
0.85
0.38
1.22
0.30
-

0.70
0.02
97.27
0.55
0.10
0.10
0.92

New Technologies for Urban Safety of Mega Cities in Asia

Cumulative passing, by vol. (%)

ICUS Report 73

100
90
80 fume
SilicaLimestone
70
60
50
40
30
20
10
0
0.01

0.1

Sand
Cement1

10100Particle Size (μm)

Figure 1. Particle size distribution of materials used in this study determinedby laser diffraction
2.2 Methods
The workability of mixtures was determined by means of flow table test. The flow
measurements were adjusted between 210 and 230 mm (according to BS 45511:1998) by changing the superplasticizer content.
Mixtures were cast into the 50mm×50mm×50mm cubes for the compression test.
3. MIX DESIGN AND MIXING PROCEDURE OF UHPC
3.1 Packing density
Optimization of granular mixture is one of the key issues in the UHPC mix design.
The optimization of granular mixtures in this study was predicted by using thepacking model developed by Larrard and Sedran (Larrard and Sedran, 1994), withthe compaction index of 12.5 (Jones et al., 2002). The granular mixture wasconsidered as a ternary system of sand, cement and admixture (silica fume andlimestone) in which the SF content was fixed at 10% by weight of binder (cement,
limestone and silica fume). The LS content was replaced about 0-20% by weghtof binder. Thus, the granular mixtures are considered as a binary system of sandand binder.

Ultra high performance concrete using a combination of silicafume and limestone in
Ultra high performance
Vietnam concrete using a combination of silicafume and limestone in Vietnam901

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamPacking density of system

0.80
0.75
0.70
0.65
0.60

0%Admixture
5%Admixture
10%Admixture
15%Admixture
20%Admixture

0.55
0.50
0.45
0.40
0

0.2

0.4

0.6

0.8

1

Percentage of Sand (%)

Figure 2: Packing density of system of sand – cement – silica fume - limestone, Binder hereinis the mixture of cement, silica fume and limestone; 10%SF is fixed
The optimized packing of this ternary system was achieved at sand / (sand +binder) ratio of 0.5 and the content of LS about 20% by weight of binder.
3.2. UHPC compositions
Based on the results of the optimized packing density of granular mixtures, UHPC
mixtures were designed with a sand / (sand + binder) ratio of 0.5. The water tobinder (w/b) ratio of the mixtures was fixed at 0.18 by weight of the binder. The
mix composition of UHPC was prepared as shown in Table 2
Table 2: UHPC compositions used in this study

No

Amount ofbinder (kg)

1
2
3
4
5
6
7
8
9

1122
1119
1116
1112
1109
1102
1099
1096
1093

Sand/binder
w/b ratio
ratio(by weight)(by weight)
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18

1
1
1
1
1
1
1
1
1

SF,
(% by
weight)LS,(% byweight)

0
0
0
0
0
10
10
10
10

0
5.0
10
15
20
5.0
10
15
20

Amount ofsuperplasticizer(% by weightofbinder)
0
0.9
0.85
0.75
0.7
0.7
0.65
0.6
0.55

3.3. Mixing, workability and curing conditions of UHPCUHPC was mixed in a Habart mixter (20 litre). The mixing procedure was shownin Figure 4.

902

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 73

2-5 min.
2-5 min.
1-2 min.
1-2 min.
1 min.1 min.
2 min.2 min.
Sand +
Sand +3 min.3 min.
PowderPowder+ mixing+ mixing
mixingmixing
SP+ SP+
mixingmixing
mixingmixing
cemetcemet++mixingmixing
End ofEnd of
ScrapeScrape
ScrapeScrape
70% 70%30% 30%mixingmixing
limestone
limestone++
and Stirand Stirand Stirand Stir
WaterWater
WaterWater
silica fumesilica fumeFigureFigure3: Mixing
3: Mixing
procedure
procedure
for UHPC
for UHPC
Mixtures
Mixtureswerewerecast castinto into
the 50mm×50mm×50mm
the 50mm×50mm×50mm
cubescubes
for thefor compression
the compression
test test
and andkept kept
in moulds
in moulds
at temperature
at temperatureof 20°C,of 20°C,
95%95%
relative
relative
humidity
humidity(RH)(RH)
for 24for 24hours.
hours.
AfterAfterdemoulding,demoulding,samplessamples
werewerestoredstoredat twoat different
two different
conditions
conditions(1) Normal(1) Normal
treatment
treatment(at 20°C(at 20°C
and 100%
and 100%
RH) RH)untiluntil
testing
testingoo(2) Steam-cured(2) Steam-cured(at 90±5(at 90±5
C and
C and
95%95%
relative
relative
humidity)
humidity)for 48
forhours,
48 hours,
afterafter
that, that,
continuous
continuous
treating
treating
at at at20°C
at 20°Cand 100%
and 100%
RH until
RH until
testing.
testing.

CompressiveCompressive
strength
strengthof samplesof samples
was wastestedtestedat theatage
the ofage3,7,of 28
3,7,and28 90
anddays.
90 days.
4. RESULTS
4. RESULTS
ANDANDDISCUSSIONDISCUSSION
4.1 Workability
4.1 Workabilityof UHPC
of UHPC
mixturesmixtures
The Theamountamountof superplasticizerof superplasticizer
usedusedin thein mixtures
the mixtures
for achieving
for achieving
the average
the average
flowflow
diameterdiameter
fromfrom
210 210
to 230mm,
to 230mm,
is presented
is presented
in Figurein Figure
4. It 4.canIt becanseenbe seenthat thatwithwiththe cement
the cement
replacement
replacement
percentage
percentage
fromfrom
0 to020%,
to 20%,
the addition
the addition
of LS
of LS
decreases
decreases
workability
workabilityof mixtures.
of mixtures.
ThisThiswas wasexplained
explainedby theby sphericalthe sphericalshapeshapeof ofLS particles,
LS particles,
which
which
act asacta aslubricant.
a lubricant.
The Theeffecteffectof LSof toLSworkability
to workabilityof UHPC,
of UHPC,
meanmeanparticleparticleof LSofisLS5μm
is 5μm, which, whichis smaller
is smaller
than thanthat ofthattheofcement
the cement
particleparticle
size.size.
Therefore,
Therefore,
the LSthe will
LS willfill thefill empty
the empty
spacespacein thein system
the system
and release
and releasewaterwater
fromfrom
pores,
pores,
it means
it means
that, that,the thefree freewaterwater
is increased
is increased
and andthus thus
improving
improving
the theworkability.
workability.
On theOn otherthe otherhand,hand,
the range
the rangeof particleof particle
size sizeof LSof between
LS betweenof theof ranges
the ranges
of ofcementcementand andsilicasilica
fumefume(Figure(Figure1), therefore1), therefore
the combination
the combinationof LSof andLS andSF canSF canmakemakethe mixture
the mixture
denserdensercomparedcomparedto thetomixture
the mixture
without
without
LS andLS SF
and(Figure
SF (Figure
3). 3).
The Thecombination
combinationof 10%of 10%SF andSF LS
andimprove
LS improve
the workability
the workabilityof UHPC
of UHPC
mixtures.
mixtures.
ThisThiswas wasexplained
explainedby theby sphericalthe sphericalshapeshapeof SFof particles,
SF particles,in which
in whichthe “ballthe “ballbearingbearing
effect”
effect”
causedcausedby theseby theseparticles
particles
will will
reducereducethe dry
the dryfrictionfriction
betweenbetweencementcementparticles,
particles,
and thus
and thus
improve
improvethe workability
the workabilityof UHPC
of UHPC
mixtures.
mixtures.
FromFrom
this thisresult,result,it raises
it raises
the idea
the ideathat that
LS mayLS maybe usedbe usedto combine
to combine
withwith
SF toSF toincreaseincrease
the theworkability
workabilityof UHPC
of UHPC
mixtures.
mixtures.
Indeed,Indeed,the theamounts
amountsof ofsuperplasticizer
superplasticizerof theof LS
the mixtures
LS mixtures
reducereducewithwith
addition
additionof 10%of 10%
SF. Moreover,
SF. Moreover,the maximum
the maximum
amountamountof cementof cement
replacement
replacementby theby combination
the combinationof LSof andLS andSF SF
can becanincreased
be increased
to 30%.
to 30%.

UltraUltrahigh highperformance
performance
concreteconcreteusingusing
a combination
a combinationof silicafume
of silicafume
and limestone
and limestone
in in
Ultra highperformance
VietnamVietnam concrete using a combination of silicafume and limestone in Vietnam903

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamSuperplastisizer amount(solid % by weight of binder)

2
1.5

LS

SF + LS(SF fixed at 10%)

1
0.5
0
0

5

10

15

20

25

30

LS, SF + LS (% by weight of total binder)

Figure 4: Amount of superplasticizer of UHPC mixtures and %LS, %(SF+LS)
for achieving a constant flow value of mixtures between 210 and 230 mm, w/b =0.18
4.2. The effect of LS on compressive strength of UHPCThe effect of LS on compressive strength of UHPC was investigated (Figure 6). It
can be seen that the compressive strength of UHPC increases with the addition of
LS. The highest compressive strength of the LS samples was achieved with using
10% LS, 137MPa and 155.3MPa with normal treatment and steam-cured,
respectively. This result is significant higher than that of the control sample
containing 0%LS. Although the compressive strength of the LS sample decreased
with an increase of the LS replacement.

Compressive strength (MPa)Compressive strength (MPa)90 days

180
160
140
28 days120

7 days100
3 days80(a) 202oC

60
40

180

90 days160
140

28 days

7 days120
100

3 days80(b) 905oC

60
40

0

5

10

15

LS (% by weight in binder)

20

0

5

10

15

20

LS (% by weight in binder)Hình 5: Effect of LS on compressive strength of UHPC
w/b = 0.18, (a) 202oC, (b) 905oC

904

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 73

Devolopment of the compressive strength with the addition of LS was shown in
Figure 7. UHPC The addition of 5% and 10% LS and cured at 20oC inscrease incompressive strength at early age. Especially, after 28 days had a very highcompressive strength but did not match that at 90 days. This was explained, thereplacement of cement by limestone strongly improves the workability of UHPC
mixtures. In addition, limes improves to disperse cement particles and create thecrystalline nucleation to promote the hydration of cement which increses thecompressive strength at early age.
The 90oC speciments can be seen achieved higher compressive strength at earlyage but this decreases more slowly at later (90 days). The speciments at 90 days is
not much higher than that at 28 days. The effect of LS on the compressive
strength is investigated. At LS contain at 5% and 10% by weight the compressive
strength increases initially but decreases afterward when LS increases (Figure 7).

Compressive strength (MPa)The highest compressive strength of the LS samples was attained with 10% LS
replacement under 20oC and 90oC curing. Therefore, the LS content of 10% wasconsidered as a maximum cement replacement value.

180
160
140
120
100
80
60
40
20
0

(a) 202oC

Rn3
Rn7
Rn28
Rn90

(0% LS)(5% LS)(10% LS)(15% LS)(20% LS)

Compressive strength (MPa)LS (% by weight in binder)
180
160
140
120
100
80
60
40
20
0

(b) 905oC

Rn3
Rn7
Rn28
Rn90

(0% LS)(5% LS)(10% LS)(15% LS)(20% LS)

LS (% by weight in binder)

Figure 6: Devolopment of the compressive strength of UHPC over time,
w/b = 0.18, (a) 202oC, (b) 905oC
Ultra high performance concrete using a combination of silicafume and limestone in
VietnamUltra high performance concrete using a combination of silicafume and limestone in Vietnam905

0ctober 2013, Hanoi, Vietnam
October 2013, Hanoi, Vietnam

4.3. Effect of combination of limestone and silica fume on compressive
strength of UHPC
The previous work (Thang et al., 2012) shows that, the amount of SF was at 10%
which was the most improvement not only workability but also compressive
strength. Therefore, the content of SF was fixed at 10% by weight of binder in thisresearch. The effect of combination of LS and SF on the 3, 7, 28, 90 day
workability and compressive strength of UHPC was studied with LS contents in
the range from 5 to 20% and with a SF content fixed at 10%. The result is
depicted in Figure 8, 9.
The results show that, the combination of LS and SF improves not only
workability but also compressive strength of UHPC mixture. Compared to the LS
samples, the compressive strength of combination LS and SF is higher at the samecontents.
It is clear that combined with 10% SF, the highest compressive strength of the
combination LS and SF samples was attained with 10% LS replacement which
was 153 MPa and 157 MPa under 20oC and 90oC curing, respectively. Under 90oC
curing, the LS replacement can be possibly increased to 15%. the compressive
strength of all samples is in excess of 150 MPa. Therefore, when 10% SF wasused, the total cement replacement by using a blend of LS and SF can reach to25%. This is very important for the sustainable development of the constructionindustry.
180
90 days160

Compressive strength (MPa)Compressive strength (MPa)

180

140
120

28 days100

7 days80
3 days60(a) 202oC

40
0

5
10
15
LS (% by weight in binder)

90 days160
140

28 days

120
100

3 days8060(b) 905oC

40
20

7 days051015LS (% by weight in binder)

20

Figure 7: Effect of LS on compressive strength of UHPC,
10%SF was fixed, w/b = 0.18, (a) 202oC, (b) 905oC
Figure 9 shows the development of the compressive strength on the 3, 7, 28, 90
day of UHPC using combination LS and SF under 20oC and 90oC curing. The
compressive strength at 20oC curing increased slowly at early age but fasterstrength gain at 90 day which did not match that of the 90oC cured specimens.
From observation of the rate of increase in strength it seems unlikely that thestrength of the 20oC cured specimens would reach that of the 90oC cured

906

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 73

Compressive strength (MPa)specimens at later ages. However, the compressive strengths of 20oC cured UHPC
is in excess of 150 MPa at 90 day.
180
160
140
120
100
80
60
40
20
0

(a) 202oC
Rn3
Rn7
Rn28
Rn90

(0% LS)(5% LS)(10% LS)(15% LS)(20% LS)

Compressive strength (MPa)LS (% by weight in binder)
180
160
140
120
100
80
60
40
20
0

(b) 905oC
Rn3
Rn7
Rn28
Rn90

(0% LS)(5% LS)(10% LS)(15% LS)(20% LS)

LS (% by weight in binder)

Figure 8: Devolopment of the compressive strength of UHPC over time,
SF was fixed at 10%, w/b = 0.18, (a) 202oC, (b) 905oC
5. CONCLUSIONSThis paper presents the possibility of using LS in combination with and without
SF to produce UHPC in order to get the benefits regarding costs, sustainability.
Following conclusions can be drawn:- Limestone can be used to replace cement to produce UHPC without decreasing
the compressive strength.
- The addition of LS strongly improves the workability of UHPC mixture. The
highest compressive strength of the LS samples was attained with 10% LS
replacement under 20oC and 90oC which was 137MPa and 155.3MPa,
respectively.
- LS in combination with SF improves not only workability but also compressive
strength, the maximum of total cement replacement percentage to 25%, in which
the percentage of LS replacement was 15%. The highest compressive strength of
Ultra high performance concrete using a combination of silicafume and limestone in
Ultra high performance
Vietnam concrete using a combination of silicafume and limestone in Vietnam907

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamthe LS samples was attained with 10% LS replacement under 20oC and 90oC
which was 153MPa and 157MPa, respectively.
REFERENCES
AFGC-SETRA 2002. Ultra High Performance Fibre-Reinforced Concretes, Paris,
France, Interim Recmmendations, AFGC publication.
BUITELAAR, P. 2004. Ultra High Performance Concrete: Developments andApplications during 25 years. International Symposium on UHPC, Kassel,
Germany.
HEIKAL, M., EL-DIDAMONY, H. & MORSY, M. S. 2000. Limestone-filled
pozzolanic cement. CEMENT and CONCRETE RESEARCH, 7.
JONES, M., ZHENG, L. & NEWLANDS, M. 2002. Comparison of particle
packing models for proportioning concrete constitutents for minimum voids ratio.
Materials and Structures, 35, 301-309.
LARRARD, F. D. & SEDRAN, T. 1994. Optimization of ultra-high-performance
concrete by the use of a packing model. Cement and Concrete Research, 24, 9971009.
RICHARD, P. & CHEYREZY, M. H. 1994. "Reactive Power concretes with highductility and 200-800 MPa compressive strength." in Mehta, P.K. (ED). Concrete
Technology: Past, Present and Future, Proceedings of the V. Mohan Malhotra
Symposium, ACI SP 144-24, 507-518. Detroit: Victoria Wieczorek.
THANG, N. C., TUAN, N. V. & HANH, P. H. 2012. Research on production of
Ultra-High Performance Concrete using materials available in Vietnam. Review of
Ministry of Construction, 71-74.
TURGUT, P. 2007. Cement composites with limestone dust and different gradesof wood sawdust. Building and Environment, 7.
VOOA, Y. L. & FOSTERB, S. J. 2010. Characteristics of ultra-high performance'ductile' concrete and its impact on sustainable construction. The IES Journal Part
A: Civil & Structural Engineering, 3, 168–187.

908

New Technologies for Urban Safety of Mega Cities in Asia

Analytical and experimental study for seismic
design of a typical bridge pier according toVietnamese earthquake design code
PHAM Hoang Kien
Lecturer, ICE, the University of Transport and Communications, Vietnam
phkien@utc.edu.vn
ABSTRACT
Lying in the tectonical position of the Indochina and southern China microplates’ boundary, Vietnam is supposed to be in the low to moderate earthquake
region in the world. In the past, some historical earthquakes with large
magnitudes of 5.0 to 6.8 Richte’ scales were recorded in northern Vietnam suchas earthquakes at Dien Bien (1935, M =6.8 and 2001, M = 5.3), earthquakes at
Luc Yen (1953, 1954, M = 5.4), earthquake at Tuan Giao (1983, M = 6.7).
Nowaday, seismic design is the compulsory issue when designing bridge andbuilding structures in Vietnam. In this paper, firstly, a brief overview of seismic
activities and design methodology stated in earthquake design code in Vietnam ispresented. Then the dynamic analyses using fiber element model and theexperimental study using shaking table test for a typical bridge pier are carriedout. In these studies, due to the lack of strong ground motion records in Vietnam,
the earthquake time-history used in non-linear dynamic analysis and shaking
table test is the artificially generated time-history which fits to design response
spectrum in Vietnamese earthquake design code. Through studies, the evaluations
on results obtained by different design methods (response spectrum method andnon-linear time-history method) are performed. It is found that the dynamic
analysis using fiber model could simulate the experimental bridge pier behavior
well.
Keywords: earthquake disaster, Vietnamese earthquake design code, fiber
element model, shaking table test
1. INTRODUCTION
Vietnam is tectonically located in the position of the Indochina and southern
China micro-plates’ boundary, and it has been classified as low to moderate
earthquake region in the world. Most of the main faults in Vietnam are strike-slip
type; it remains tectonically active as shown by the occurrence of moderate
earthquakes in the country and adjacent areas. In the research project named“Research and Forecasting Earthquakes and Ground Movements in Vietnam”,
which was implemented by the Vietnam Institute of Geophysics (VIG,2005), it isfound that from 114 AD to 2003 AD Vietnam, either by measurement or bystudying the historical archives, recorded 1645 earthquakes with magnitude (M)of 3.0 to 6.8 Richter’s scale. In the past, Vietnam had been considered as a safe909

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamcountry with respect to earthquake disaster. However, recent earthquakes in the
North and the South of the country made the government and society pay more
attention to earthquake hazard risk. If large earthquakes occur in urban areas suchas Hanoi and Ho Chi Minh city, the damages and losses may possibly be much
more than those caused by typhoons or floods. Seismic design is now thecompulsory issue when designing bridge and building structures in Vietnam. In
this paper, the following contents are studied: (i) seismic activities in Vietnam; (ii)design methodology in Vietnamese earthquake design code; (iii) dynamic
analyses using fiber element model and experimental study using shaking table
test for a typical bridge pier. Due to the lack of strong ground motion records in
Vietnam, the earthquake time-history used in non-linear dynamic analysis andshaking table test is the artificially generated time-history which fits to design
response spectrum in Vietnamese earthquake design code.
2. SEISMIC ACTIVITIES IN VIETNAM
Results of a research project of the Vietnam Institute of Geophysics (VIG, 2005)
showed that in the 20th century Vietnam had two earthquakes with intensity I0 = 8
÷ 9 (MSK-64) and magnitude (M) of 6.5 ÷ 7 of Richter’s scale, 15 earthquakes
with I0 = 7 and M = 5 ÷ 5.9, and more than 100 earthquakes with I0 = 6 ÷ 7 and
M = 4.5 ÷ 4.9. Seismic research by the VIG has also established a zoning map for
maximum credible earthquakes in Vietnam (Figure 1).

Figure 1: Maximum credible earthquakes in Vietnam (Cao, 2006)

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From 1900 to 2001 strong earthquakes were recorded in the North of Vietnam,
also in the Hanoi area. Two strongest earthquake were the Dien Bien earthquake(1935, M = 6.8) and Tuan Giao earthquake (1983, M = 6.7). All these earthquakes
occurred in the Northwest of Vietnam, close to Chinese Yunan province and Laos.
Many houses suffered damage and collapse during these two strong earthquakes.
On 19 February 2001, a strong earthquake with recorded magnitude (M) of 5.3 ofRichter’s scale and intensity (I0) of 7 ÷ 8 had occurred in Dien Bien Phu area (theepicenter in Nam Oun (Laos), about 15 km from Dien Bien Phu city). There were
hundreds of aftershocks of which the strongest had magnitude up to 4.9. The
earthquake caused destruction of building and constructions in the area of
thousands square kilometers. There were 130 houses damaged and needed to bereconstructed, 1044 houses needed to be strengthened or retrofitted, 2044 houses
slightly damaged and 4 people injured.
South of Vietnam is the region where the seismic activities were considered very
low and the effects of earthquakes on structures were not needed to be considered.
Therefore, when the earthquakes occurred in this region in August and November
2005, it surprised many scientists. These two earthquakes (with M = 4.6 and I0 =5
occurred on 5 August 2005 and with M = 5.5 occurred on 8 November 2005)
could possibly be the strongest earthquakes in the South of Vietnam. It is said that,these seismic activities, both in the North and the South of Vietnam, made thegovernment and society pay more attention to earthquake hazard risk. At present
time, Vietnamese Seismological Network is established and it can monitor theseismic events of magnitude larger than 3.0 in the territory of Vietnam. Figure 2
shows the time history of the Dien Bien earthquake (2001) recorded at Dien Bien
station.

Figure 2: Time history of the Dien Bien earthquake (2001) recorded at Dien Bien
station (DBV-21o23.38’N, 103o01.10’E).
3. METHODOLOGY IN VIETNAMESE EARTHQUAKE DESIGN CODE
The specification for bridge design in Vietnam (named as 22TCN 272-05) is basedon the AASHTO LRFD 1998. Seismic design is only a part of 22TCN 272-05.
Analytical and experimental study for seismic design of a typical bridge pier according toVietnamese earthquake design code
Analytical and experimental study for seismic design of a typical bridge
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VietnamVietnam also has an earthquake-resistant design specification mainly applied forbuilding structures (named as TCXDVN 375-2006), which is based on the
EUROCODE 8. The object of study in this paper is bridge pier so seismic design
methodology in 22TCN 272-05 will be introduced.
3.1 Seismic design in 22TCN 272-05
3.1.1 Seismic performance zones
22TCN 272-05 requires that each bridge shall be assigned to one of the three
seismic zones with corresponding acceleration coefficient as shown in Table 1.
Table 1: Seismic zones
Acceleration coefficient
Seismic zone
MSK - 64 class1
A  0.09
Class  6.5
2
0.09 < A  0.19
6.5 < Class  7.5
0.19 < A < 0.29
3
7.5 < Class  8
3.1.2 Elastic seismic response coefficient
The elastic seismic response coefficient, Csm for the mth mode of vibration shall betaken as:
1.2AS
(1)
Csm= 2 / 3  2.5A
Tm
where:
Tm =period of vibration of the m th mode (s)A=acceleration coefficientS=site coefficient
The determination of the period of vibration, Tm, should be based on the nominal,
unfactored mass of the component or structure. For soil profiles III and IV, andfor modes other than the fundamental mode that have periods less than 0.3s, Csm
shall be taken as:
Csm = A(0.8 + 4.0 Tm)(2)

If the period of vibration for any mode exceeds 4.0 s, the value of Csm for thatmode shall be taken as:
3AS
Csm  4 / 3(3)Tm
An example of elastic seismic response coefficient is shown in Figure 3.

Figure 3: Example of elastic seismic response coefficient

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3.1.3 Seismic design methodology(1) Selection of design method
For multispan structures, the minimum analysis requirements are specified asshown in Table 2 in which:*= no seismic analysis required
UL = uniform load elastic method
SM = single-mode elastic method
MM = multimode elastic method
TH = time history method

Seismic
Zone
1
2
3

Table 2: Minimum analysis requirements for seismic effects
Multispan Bridges
SingleSpan
Other Bridges
Essential Bridges
Critical Bridges
Bridgesregular irregular regular irregular regular irregular
No seismic
*
*
*
*
*
*
analysis
SM/ ULSM
SM/ ULMM
MM
MM
required
SM/ UL
MM
MM
MM
MM
TH

(2) Single-Mode Methods of Analysis
Either of the two single-mode methods of analysis specified herein may be used
where appropriate.
 Single-Mode Spectral Method
The single-mode method of spectral analysis shall be based on the fundamental
mode of vibration in either the longitudinal or transverse direction. This modeshape may be found by applying a uniform horizontal load to the structure andcalculating the corresponding deformed shape. The natural period may be
calculated by equating the maximum potential and kinetic energies associatedwith the fundamental mode shape. The amplitude of the displaced shape may befound from the elastic seismic response coefficient, Csm, and the corresponding
spectral displacement. This amplitude shall be used to determine force effects.
 Uniform Load Method
The uniform load method shall be based on the fundamental mode of vibration ineither the longitudinal or transverse direction. The period of this mode ofvibration shall be taken as that of an equivalent single mass-spring oscillator. The
stiffness of this equivalent spring shall be calculated using the maximum
displacement that occurs when an arbitrary uniform lateral load is applied to thebridge. The elastic seismic response coefficient, Csm, shall be used to calculate theequivalent uniform seismic load from which seismic force effects are found.
(3) Multimode Spectral Method
The multimode spectral analysis method shall be used for bridges in which
coupling occurs in more than one of the three coordinate directions within eachmode of vibration. As a minimum, linear dynamic analysis using a threedimensional model shall be used to represent the structure. The number of modes
included in the analysis should be at least three times the number of spans in
the model. The elastic seismic response spectrum shall be used for each mode.
The member forces and displacements may be estimated by combining therespective response quantities (moment, force, displacement, or relative
Analytical and experimental study for seismic design of a typical bridge pier according toVietnamese earthquake design code
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Vietnamdisplacement) from the individual modes by the Complete Quadratic Combination(CQC) method.
(4) Time-History Method
Any step-by-step time-history method of analysis used for either elastic or
inelastic analysis shall satisfy the requirements. The sensitivity of the numericalsolution to the size of the time step used for the analysis shall be determined. A
sensitivity study shall also be carried out to investigate the effects of variations inassumed material hysteretic properties. The time histories of input acceleration
used to describe the earthquake loads shall be selected in consultation with the
Owner. Unless otherwise directed, five spectrum-compatible time histories shallbe used when site-specific time histories are not available. The spectrum used togenerate these five time histories shall be the same as that used for the modal
methods.
4. TIME HISTORY ANALYSIS AND SHAKING TABLE TEST FOR A
BRIDGE PIER
4.1 Test specimen
Figure 4 shows the specimen tested in this study. This is a 1/8-scale model. The
column diameter is 375 mm, and the height from the bottom of the column to thecenter of gravity of the top mass is 1400 mm, resulting in an effective aspect ratioof 3.7. Steel plates that idealize the inertia mass and dead load from superstructure
are firmly integrated at the top of specimen. The inertia mass is 1,300 kg. The
specimen is reinforced longitudinally with 8 of 18-mm diameter deformed bars
(D18). Hoop reinforcement of 6-mm diameter deformed bars (D6) is used toconfine the concrete core, spaced at a 100-mm pitch. The D10 and D6 bars haveyield strengths of 400 MPa. The strength of concrete was 30 MPa.

a

20

260

800

600

100

b

345

Ø18@124

Ø6

30

375

1250

1250

375

30

SECTION 1-1

Ø6

Ø6 @ 100

Ø28 @ 129c
700

Figure 4: Test specimen

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Figure 5: Test set up
4.2 Input ground motion
Due to the lack of strong ground motion records in Vietnam, the earthquake timehistory used in shaking table test is the artificially generated time-history whichfits to design response spectrum in 22TCN 272-05 (Figure 3). Basic input groundmotion used in test is shown in Figure 6.

Figure 6: Basic input ground motion used in shaking table test
4.3 Analysis using fiber element model
Figure 7 shows the fiber model used in analytical simulation. Fiber model
discretizes and analyzes the section of a beam element into fibers, which only
deform axially. When a fiber model is used, the moment-curvature relationship ofa section can be rather accurately traced, based on the assumption of the stressstrain relationship of the fiber material and the distribution pattern of sectional
deformation. Especially, it has the advantage of considering the movement of
neutral axis due to axial force. On the other hand, a skeleton curve based
hysteresis model has a limitation of accurately representing the true behavior
because some behaviors of a beam element under repeated loads have been
Analytical and experimental study for seismic design of a typical bridge pier according toVietnamese earthquake design code
Analytical and experimental study for seismic design of a typical bridge
915
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October
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Vietnamidealized. In a fiber model, the status of fibers is assessed by axial deformations
corresponding to the axial and bending deformations of the fibers. The axial force
and bending moments of the section are then calculated from the stress of eachfiber. The properties of nonlinear behavior of a section in a fiber model aredefined by the stress-strain relationship of nonlinear fibers.

Figure 7: Structure model in analytical simulation
4.4 Dynamic response of the selected bridge pierFigure 8 shows dynamic acceleration and displacement response at the top mass.
The results of both analytical simulation and shaking table test are presented at thesame figure. The input ground motion used in this analysis and shaking table test
has amplitude 2 times larger than the basic one shown in Figure 6.
Shaking table tests were performed at University of Transport andCommunications, Hanoi, Vietnam. Shaking table of University of Transport andCommunications is the second one installed in Vietnam. The tests presented inthis study are one of the first shaking table tests implemented in Vietnam.
Comparing the results, it is found that the dynamic analysis using fiber model
could simulate the experimental bridge pier behavior well.

(a) Acceleration response at the top mass

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ICUS Report 73(b) Displacement response at the top mass
5. CONCLUSIONSIn this study, firstly, a brief overview of seismic activities in Vietnam issummarized and seismic design methodology in Vietnamese design code ispresented. Then to investigate the dynamic response of a typical reinforced
concrete bridge pier, an earthquake simulation test and dynamic analyses are
conducted. Below are the conclusions determined from this study:(1) Vietnam had been considered as a safe country with respect to earthquake
disaster. However, recent earthquakes in the North and even in the South
made the government and society pay more attention to earthquake hazard risk.
(2) If large earthquakes occur in urban areas such as Hanoi and Ho Chi Minh city,
the damages and losses may possibly be much more than those caused bytyphoons or floods.
(3) For a typical reinforced concrete bridge pier, generally, seismic design is not
the critical one which decides bridge pier design.
(4) The dynamic analysis using fiber model could simulate the experimental
bridge pier behavior well.
(5) Experimental test using shaking table should be further conducted in Vietnam
to utilize the test equipments for earthquake hazard risk management.
ACKNOWLEDGEMENT
Supports for this research were provided by the Ministry of Education andTraining (MOET, Vietnam) and the University of Transport and Communications(UTC, Hanoi, Vietnam). The author extends his appreciation to MOET for
financial support, and to UTC for allowing using shaking table test equipment of
the University.

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REFERENCES
22TCN 272-05, 2005. Specification for Bridge Design. Ministry of Transport ofVietnam, Vietnam.
AASHTO LRFD, 1998. Load and resistance factor design (LRFD) specifications
for highway bridges. Washington (DC): American Association of State Highway
and Transportation Officials (AASHTO).
Ali, M. S., Mohammad, J. and Bashir, A., 2012. Experimental Seismic
Performance Evaluation of Bridge Piers Constructed In Low Grade Concrete.
Journal of Mechanical and Civil Engineering, Volume 3, Issue 6, 36-41
Clough, R.W. and Penzien, J., 2003. Dynamics of Structures, Third Edition,
Computers & Structures, Inc.
Hung, T. V., 2012. Study on Earthquake Ground Motion Prediction and its
Application to Structural Response of Bridge in Vietnam. Doctor dissertation,
Waseda University, 163 pages, Japan.
Kawashima, K. and Unjoh, S., 2004. Seismic design of highway bridges. Journalof Japan Association for Earthquake Engineering, Vol.4, No.3 (Special Issue),174-183.
Ngo, T.D., Nguyen, M.D. and Nguyen, D.B., 2008. A review of the Current
Vietnamese Earthquake Design Code. Special Issue of the Electronic Journal of
Structural Engineering (EJSE): Earthquake Engineering in the low and moderate
seismic regions of Southeast Asia and Australia, 32-41.
Phuong, N.H., 1991. Probabilistic assessment of earthquake hazard in Vietnam
based on seismotectonic regionalization. Tectonophysics, Vol. 198(1), 81-93.
Sakai, J. and Unjoh, S., 2006. Earthquake simulation test of circular reinforced
concrete bridge column under multidirectional seismic excitation. Earthquake
engineering and engineering vibration, Vol. 5, No. 1, 103-110.
VIG, 2005. Research and Forecasting Earthquakes and Ground Movements in
Vietnam (Researched by Vietnam Institute of Geophysics, Chairman - Prof.
Nguyen Dinh Xuyen), Hanoi, Vietnam (in Vietnamese).

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Influence of climate change to loads
and actions to buildings
NGUYEN Vo Thong
Associate Professor, Vietnam Institute for Building Science and Technology(IBST), Vietnam
thongnguyenvo@gmail.com

ABSTRACT
Global Climate Change being happened increase natural effects: temperature,typhoons, floods, droughts, earthquakes, tsunamis in more severe, frequent,intensity occurrences. This paper presents influence of climate change to loads
and actions to buildings.
Keywords: Loads, actions, climate change.
1. INTRODUCTION
From recent studies, climate change have occurred in the world and effected to all
nations and life in the earth. Climate change has resulted in more severe and/or
frequent occurrences of natural disasters, especially cyclonic storms, floods anddroughts becoming more extreme. Viet Nam is likely to be one of the several
countries most adversely affected by climate change. This paper presents theinfluence of climate change to loads and actions to buildings.

2. CAUSES AND PREDICTIONS OF CLIMATE CHANGE IN THE
WORLD AND IN VIET NAM
2.1 Causes of climate change
Climate change is a significant and lasting change in the statistical distribution of
weather patterns over periods ranging from decades to millions of years (Ministryof Resources and Environment, 2009). It may be a change in average weather
conditions, or in the distribution of weather around the average conditions (i.e.,
more or fewer extreme weather events). Climate change is caused by factors that
include oceanic processes (such as oceanic circulation), biotic processes,
variations in solar radiation received by Earth, plate tectonics and volcanic
eruptions, and human-induced alterations of the natural world; these latter effects
are currently causing global warming. Climate change in the during period XX
century to now was paid attention by people. Some recent studies showed thatnaturally occurring green house gases such as CO2 and CH4 are main reason for919

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamclimate change, especially the industrialization in the world from 1950 andconsumption, relating to fossil fuel use such as coal, oil, cement production,
deforestation, increasing the number of cattle (increasing amount of CH4) and
exploitation under water territory with peat coal.
2.2 Some climate change projections in the world and in Viet Nam

Figure 1: Observed global surface temperature
anomaly during period the 1860-2000

Sea level (mm)Global mean temperature (oC)

Difference (oC) from 1961-1990

The main phenomenon of climate change is global warming and associated sea
level rise. According to the 4th report of Intergovernmental Panel on Climate
Change (IPCC) in 2007 (IPCC, 2007), The 100-year linear trend (1906-2005) of
0.74 [0.56 to 0.92]°C is larger than the corresponding trend of 0.6 [0.4 to 0.8]°C(1901-2000). The linear warming trend over the 50 years from 1956 to 2005 (0.13[0.10 to 0.16]°C per decade) is nearly twice that for the 100 years from 1906 to2005 (Figure 1).

Figure 2: Observed global mean sea levelanomaly during period the 1860-2000

The increasing of temperature causes the ice in Earth's North and South Poles
melting to increase sea level. Data from TOPEX/POSEIDON satellite show thatduring period the 1993-2003 sea level rose by between 3,1 mm - 0,7 mm per year
(Figure 2), faster than period the 1961-1993 (IPCC, 2007).
During the last 50 years, Viet Nam’s annual average surface temperature has
increased by approximately 0.7oC. The average temperatures in 2007 in Ha Noi,
Da Nang, Ho Chi Minh are higher 0,8oC ÷ 1,3oC, 0,4oC ÷ 0,5oC than that of thedecades 1931-1940 and 1991- 2000, respectively. Sea level in Cua Ong and Hon
Dau increased about 20 cm. In the last two decades, the number of cold fronts
crossing Viet Nam decreased, for example there were only 15-16 cold fronts (56%average number of several years) in 1994 and 2007. A strange phenomenon ofclimate there are several and long lasted very cold fronts, last 38 days in January
and February of 2008. Average number of rainy days in year in Ha Noi decreased
in decade 1981-1990 and is half (15 days per year) in the last ten years. At thesame time, the number of typhoons with higher intensity, typhoon track move tosouth lattices, typhoon season is likely to end later and there are typhoons withstrange track. After typhoons, floods, landslides often happen. Changes of natural
conditions from climate change caused many influences of climate change toloads and actions to buildings.

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3. INFLUENCES OF CLIMATE CHANGE TO LOADS AND ACTIONS TO
BUILDINGS
3.1 Effects of temperature
According to the medium emission scenario, to the end of 21st decade, averagetemperature may increase to 2.60C in the North West, 2.50C in the North East,
2,40C in the North Delta, 2.80C in the North Central, 1.90C in the South Central,
1.60C in the Central Highlands and 2.00C in the South compared to average valuesof decade 1980-1999 (Ministry of Resources and Environment, 2009). The
irregularity of the increasing of average temperature happen on regions. North
Central has the highest increasing in temperature, and then turns to the North
West, the North East, the North Delta, the South Central, the South and theCentral Highlands (Table 1).
Table 1: Projections of average increase in temperature (0C) during period the
1980-1999 in the medium emission scenario
Region2020
North West
0.5
North East
0.5
North Delta
0.5
North Central
0.5South Central
0.4
Central Highlands 0.3
South
0.4

2030
0.7
0.7
0.7
0.8
0.5
0.5
0.6

2040
1.0
1.0
0.9
1.1
0.7
0.6
0.8

2050
1.3
1.2
1.2
1.5
0.9
0.8
1.0

Year
2060
1.6
1.6
1.5
1.8
1.2
1.1
1.3

2070
1.9
1.8
1.8
2.1
1.4
1.2
1.6

2080
2.1
2.1
2.0
2.4
1.6
1.4
1.8

2090
2.4
2.3
2.2
2.6
1.8
1.5
1.9

2100
2.6
2.5
2.4
2.8
1.9
1.6
2.0

Beside the increase of temperature, hot summer and coldness are also stronger.
Temperatures reaching peak in hot summers have an increasing trend andtemperatures of cold winters have the decreasing trend (Table 2). Area of region
affected hottest summer and coldest winter extend to South direction. The
durations of hottest summer and coldest winter last longer. Phenomenon of ice
and snow appeared in Sa Pa, Lang Son and high land areas in the North has a
increasing trend.
If consider the annual increasing of temperature according to the medium
emission scenario effects of temperature to structures increase higher than data in
QCVN 02:2009/BXD (Table 3).
From data in Tables 1, 2 and 3, climate change affect to effects of temperature tobuildings. When to design buildings, especially temperature-sensitive buildings it
is need to consider unfavorable effects of temperature because of climate change
to stress behavior, deformation and reasonable design solutions. Besides,
stipulations relating data and effects outdoor temperature: Natural Physical &Climatic Data for Construction (QCVN 02:2009/BXD, 2009), length and width ofthermal slot of structural types: concrete, reinforced concrete structures (TCVN
5574:2012, 2012) and steel structures (TCVN 5575:2012, 2012)... will needsuitable studies and revisions.

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Table 2: Hottest summers and coldest winters have the increasing trend intensityand duration
Hottest summer
Coldest winterTemperTemperDuration
Duration
Year Location ature
Note
Year Region ature
Note
(day)
(day)
0
0
( C)
( C)
1983 Ha Noi 40.4
2/1968 Sa Pa<026
Ice and snow
Lang
40.7
2/1989 Sa Pa<028
Ice and snow
Son Tay
40
1973-3
Ice and snow
Measured
Tinh Gia 40.2
Sa Pa
-2
Ice and snow
10
6/2010in
Quy Hop 40.7
Mau Son -5
Ice and snow
38
weather 2/2008
Con
40.8
Ha
Noi
7
tent
Cuong
Ha Noi40
Mau Son -1,9
Ice and snow
13
1/201118
4/2012
Hoa Binh 42
Ha Noi8-

Table 3: Average increasing of temperature compared with data of QCVN
02:2009/BXD

2030
3.18
3.03
2.97
3.35
1.88

Temperature
Increasing with time (%)
2040 2050 2060 2070 2080 2090 2100
4.55 5.91 7.27 8.64 9.55 10.91 11.82
4.33 5.19 6.93 7.79 9.09 9.96 10.82
3.81 5.08 6.36 7.63 8.47 9.32 10.17
4.60 6.28 7.53 8.79 10.04 10.88 11.72
2.63 3.38 4.51 5.26 6.02 6.77 7.14

2.12

2.54

3.39

4.66

5.08

5.3

6.36

6.78

2.19

2.92

3.65

4.74

5.84

6.57

6.93

7.30

Location

Averagetemperature 2020
Dien Bien
220C
2.27
0
Ha Long23.1 C
2.16
Ha Noi23.60C
2.12
0Vinh
23.9 C
2.09
Nha Trang
26.60C
1.50
Buon Me
23.60C
1.27
Thuot
Ho Chi
1.46
27.40C
Minh

3.2 Effects of strong winds
Formally, typhoons hit Vietnam the North in August, the Central in October andthe South in December. Recently, typhoons occur lately and are gradually moving
south. Climate change creates the increasing of sea temperature, warm water area
extending to high latitudes of Pacific Ocean. As the result, typhoons occur more
frequently in the Northwestern Pacific Ocean. wherefore number of typhoons
hitting Viet Nam will increase. Wind speed and period of typhoons also increase.
Many strong wind phenomena (squall, tornado or downburst) with high intensity
last longer and not follow normal rules. Formally, whirlwinds often occur in
midland region but now they occur in big cities, cause many damages of humanand properties.
The changes of typhoons and whirlwinds because of climate change are needed toresearch to help revision work of effects of wind loading in Vietnam Standard
TCVN 2737-1995. Firstly, wind region map revised from updated data makes a922

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safety assurance to buildings and recommendations of building design understrong wind phenomena (squall, tornado or downburst).

b) Bac Kan (8 Aug 2012)a) Thai Nguyen (1 Sep 2011)
Figure 3: Damages by whirlwinds
3.3 Effects of strong floods and flash floods
Flood is an overflow of water that submerges land, which is normally lower andsunken area. Strong floods on rivers change slowly and often occur in large areaand longer. Flash floods with sudden and violent behavior change fast and occur
in narrow area and affected area is smaller than that of river flood. If heavy rain
occurs, water is stopped by barriers such as stones and trees until water amountdestroy barrier and run off very fast, sweep away soil, trees and other barriers.
Normally flash floods occur rapidly in period from three hours to six hours.
Flood is a very dangerous hydrologic phenomenon, especially flash flood (Figure4). It has a violent damage and become a natural disaster, for example the flash
flood in Lai Chau city in 1998 destroyed whole Muong Lay village and area ofcity. Flash floods often occur in mountainous areas where have high mountains
with valleys, low streams and rivers.
Flash floods are classified three types:- Flash floods occur due to local rain, especially in natural basin (almost no
effect from human);- Flash floods occur due to heavy rain in basins strongly affected by economic
activities from human to cause instability and non-equilibrium of basin ecology(change top layer, stream condition, volume or characteristics of basin...);- Flash floods occur due to failure of dams and other hydraulic structures.
Climate change modifies precipitation in areas, increasing in the rainy season anddecreasing in the dry season. Flash floods occur more frequently and have higher
intensity because natural environment are destroyed. In 2007, from the beginningof October to 15 November, Central had five big floods, caused 155 death-toll, 13
missing persons, 147 injured persons, loss in facilities and farm produce up to
4,434 billion VND.
Loads and actions of floods, flash floods to buildings, roads, bridges, and drains...
are large. Therefore, there is a need of planning for areas with floods and flash
floods. When design structures for flood and flash flood resistance it needs toconsider and collect updated data relating to flash floods (dykes, dams, water

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andto
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October
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Vietnambarriers, water reservoir...) and study to revise data relating to floods and flash
floods in Natural Physical & Climatic Data for Construction suitability.
Table 4: Some flash floods during period the 1990 - 2005
No

Date

Affected region

River, stream

RainfallLoss
PeopleIn-cash(Dead/(billion
Injured) VND)

4 small lakes
370
22
destroyed
2
Nam Lay stream
233
104/200
Nam La and Nam
3
27/7/199
Son La town
403
42
Pan streams
4
23/7/1998Muong Lay, Lai Chau Nam Lay stream
187
34
5
17/8/1996
Lai Chau258
89
6 29-30/7/1999Ham Tan, Binh Thuan
Dinh river
300
27
Nam Coong, Sin Ho
7
3/10/2000
138
39
Lai Chau
8 19-20/9/2002 Huong Son, Ha Tinh Ngan Pho river 500-700 53/111
200 Du Gia, Yen Minh, Ha
45/16
9 18-19/7/2004
300
Giang
10 27-28/9/2005 Van Chan, Yen Bai
233
50/8
1

Krong Bong, Ging
Son, Lak, Đac Lac
27/6/1990
Lai Chau town
16/6/1990

3,4
22
26
18
21
187
2
824
50
162

a) Flash flood dated 27 Sep 2005b) Flash flood dated 26 June 2011 in Tuong Duongin Yen Bai caused 42 people dead(Nghe An) caused several hundreds of houseor missing
inundated, many houses and a suspension bridge swept
Figure 4: Flash floods in Yen Bai and Nghe An
3.4 Corrosion effects
Corrosion effects by climate change to building structures maybe direct effect of
sea air and sea water or acid rain. According to research by (Ministry of
Resources and Environment, 2009), up to end of 21st century, sea water level may
rise up to 1m (Table 5) compare to period from 1980-1999. At that time, if there isno plan to built sea dyke and embankment, forty thousand square kilometer ofVietnam’ coast plain will be flooded. Especially, in Mekong delta area, about
38% of area will be submerged, 90% of area will become salinity (Ministry of924

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Resources and Environment, 2009). Structures in these areas will be directly
affected by sea air and sea water.
Table 5: Sea water level up compared to period 1980 ÷ 1999
Scene
Low
MediumHigh

Years2020 2030 2040 2050 2060 2070 2080 2090 2100
11
17
23
28
35
42
50
57
65
12
17
23
30
37
46
54
64
75
12
17
24
33
44
57
71
86
100

The cause of acid rain is the increasing of sulfur and nitro oxide in the atmospherefrom natural and artificial actions. When it rains, under the action of solar
radiation, these oxides react with water in the atmosphere to create acids such as
H2SO4, HNO3 (Figure 5a).

a)

b)

c)

Figure 5: Acid rain and corrosion effects to structures
These acid drops when fall down to structures will corrode them. For example,
Capitol Building in Ottawa was heavily damaged because the volume of SO2 in
the air is too high (Figure 5b); statue was corroded by acid rain (Figure 5c); Silver
bridge at Ohio river (USA) was collapsed because anchor of suspended cable wascorroded by acid rain, caused 46 death-toll (Figure 6).

a)b)
Figure 6: Silver bridge over Ohio river before collapsed (a) and after collapsed (b)due to corrosion of suspended cable by acid rain

Influence of climatechangeto loads
andto
actions
to buildings
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From above matters, it is necessary to research, plan areas maybe directly affectedby corrosion when sea level increases and simultaneously compile design
guidelines about preservation and maintenance for structures suffered fromcorrosion caused by climate change.
3.5 Effect of sea waves and pressure by increasing of sea level
Sea wave may be caused by wind, storm, or earthquake under the sea. Sea wave
directly affect to the structures offshore and at the coast line. Damage caused bywave is very large, especially tsunami (Figures 7 and 8). Climate change makes
the sea level increase so that effects from water pressure, sea wave to structures,
especially dyke, embankment, bride, port, salinity protect system…, increase.
There are some structures such as dike, embankment, bride, port were constructedbut did not consider the possibility of sea level increasing, hence usage time andeffectiveness were affected. Therefore, sea level increasing matter must be studied
in order to propose measures to overcome for existing and newly-built structuresat the coast line area.

Figure 7: Tsunami in Japan

Figure 8: Effect of Nock-ten tropical cyclone in
Do Son, 30 July 2011

3.6 Earthquake and tsunami
Researches by Australia National University shows that, earthquakes occurred
recently resulted from global warming phenomenon. According to theseresearches, Climate change in long period may change the structure of the earth
crust, create forces affecting movement of tectonics. Earthquake will occur when
the pressure at the boundary of tectonics reach threshold level.
Vietnam is located at the South-East part of Eurasia plate, between Indian plate,Philippines plate and Australian plate. Vietnam is not located at the boundary ofthese plates; therefore it is not vulnerable to earthquake compared to othercountries in the area such as Indonesia, Philippines, Malaysia. However, on the
territory of Vietnam, there are several active faults such as Lai Chau - Dien Bien
fault, Song Ma Fault, Son La fault, Hong river fault, Ca river fault , 1090-1100
longitude fault…(Figure 9) (Le and et al., 2011),. Therefore, global tectonic
change caused by sea level increasing may affect to these faults and wake up
earthquakes. In addition, Viet Nam also suffers from earthquakes from out of
territory, especially effect of tsunami. According to researches of Viet Nam
Institute of Geophysics (Le and et al., 2011), earthquakes in the aera of East Sea
and nearby may cause tsunami to Viet Nam coast line includes: 1) Ryukyu –Taiwan, 2) Manila subduction zone, 3) Sulu sea, 4) Celebes sea, 5 và 6) Ban Đa926

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sea, 7) North of East Sea, 8) Palawan and 9) West of East Sea. Among them,
Manila subduction zone is considered highest vulnerability (Figure 10).
Follow scenarios calculated by the Ministry of Resources and Environment, if anearthquake with magnitude of 8.3 Richter occur at the Manila subduction zone, it
may cause a tsunami with the height of wave up to 6.2 m at Quang Ngai and 2.1m
at Nha Trang. If an earthquake with magnitude of 8.3 Richter occur at the same
location, it may cause a tsunami with the height of wave up to 10.6 m at Quang
Ngai and 5 m at Nha Trang, and the time for tsunami to travel from Manila
subduction zone to Viet Nam coast line is about 2 hours (Le and et al., 2011).

Figure 9: Seismic map for territory Figure 10: Sources of earthquake and tsunami
of Vietnam and nearby area.
may affect coast line and offshore islands ofViet Nam
From above results, it can be seen that climate change can affect to earthquake
and tsunami action to structures in Viet Nam. Therefore, it is necessary to havestudies to evaluate and forecast earthquake and tsunami vulnerability caused bysea level increasing. These data’s are the base to revise or reestablish seismic
zoning map in QCVN 02:2009/BXD and seismic design standard TCVN
9386:2012.
4. CONCLUSIONS
Climate change have been affecting to loads and actions to buildings. The clearest
manifestations are effects of outdoor temperature, typhoons, whirlwinds, floods,
corrosions, water waves, sea level rises, earthquakes and tsunamis.
Temperature-sensitive buildings need to consider unfavorable effects oftemperature because of climate change to stress behavior, deformation andreasonable design solutions. Besides, stipulations relating data and effects outdoor
temperature: Natural Physical & Climatic Data for Construction (QCVN
02:2009/BXD, 2009), length and width of thermal slot of structural types:
concrete, reinforced concrete structures (TCVN 5574:2005, 2012) and steel
structures (TCVN 5575:2012, 2012)... will need suitable studies and revisions.
The changes of typhoons and whirlwinds because of climate change are needed toresearch to help revision work of effects of wind loading in Vietnam Standard
Influence of climatechangeto loads
andto
actions
to buildings
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TCVN 2737-1995. Firstly, wind region map revised from updated data makes asafety assurance to buildings and recommendations of building design understrong wind phenomena (squall, tornado or downburst).
There is a need of planning for areas with floods and flash floods. When design
structures for flood and flash flood resistance it needs to consider and collectupdated data relating to flash floods (dykes, dams, water barriers, water
reservoir...) and study to revise data relating to floods and flash floods in Natural
Physical & Climatic Data for Construction suitability.
From above matters, it is necessary to research, plan areas maybe directly affectedby corrosion when sea level increases and simultaneously compile design
guidelines about preservation and maintenance for structures suffered fromcorrosion caused by climate change.
Climate change makes the sea level increase so that effects from water pressure,sea wave to structures, especially dike, embankment, bride, port, salinity protect
system…, increase. These unfavorable results must be studied in order to propose
measures to overcome for existing and newly-built structures at the coast line area.
Especially, large structures with long life time such as “live together with flood”
structures at the Mekong delta, North-South sea embankment must be carefully
studied so that structures are built today can be used for next generations.
Climate change can affect to earthquake and tsunami action to structures in Viet
Nam. Therefore, it is necessary to have studies to evaluate and forecast earthquake
and tsunami vulnerability caused by sea level increasing. These data’s are the baseto revise or reestablish seismic zoning map in QCVN 02:2009/BXD and seismic
design standard TCVN 9386:2012.
REFERENCES
IPCC, 2007. The 4th assessment report of the Intergovernmental Panel on
Climate change.
Le Huy Minh and Nguyen Hong Phuong, 2011. Vulnerability of earthquake andtsunami in Viet Nam.
Ministry of Resources and Environment, 2009. Scenarios for climate change andsea level increasing for Viet Nam.
QCVN 02:2009/BXD, 2009. National Building Code – Natural data forConstruction Activities.
TCVN 9386:2012, 2012. Design of structures for earthquake resistance.
TCVN 5575:2012, 2012. Steel structures – Design standard.
TCVN 5574:2012, 2012. Concrete and reinforced concrete structures – Design
standard.
TCVN 2737:1995, 1995. Loads ands actions-Design standard.

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Test methods for evaluation of
sulfate resistance of limestone powder
replacing cement mortars
Ittiporn SIRISAWAT1, Warangkana SAENGSOY2, Lalita BAINGAM1,
Pitisan KRAMMART3 and Somnuk TANGTERMSIRIKUL4
1
Graduate Student, School of Civil Engineering and Technology,
Sirindhorn International Institute of Technology, Thammasat University, Thailand
ittiporn@g.swu.ac.th2
Researcher, Construction and Maintenance Technology Research Center,
Sirindhorn International Institute of Technology, Thammasat University, Thailand
3
Assistant Professor, Department of Civil Engineering,
Rajamangala University of Technology Thanyaburi, Thailand
4
Professor, School of Civil Engineering and Technology,
Sirindhorn International Institute of Technology, Thammasat University, Thailand
ABSTRACTThis study is aimed to indicate the inadequacies of the presently used methods fortesting sulfate resistance of cementitious systems, especially when tested inmagnesium sulfate solution, and propose proper laboratory tests for evaluating
the sulfate resistance of mortars with various types of binders. The test methods
involved immersion of mortar specimens in 33,800 ppm of sodium sulfate (NS)and magnesium sulfate (MS) solutions. The resistance of mortars with different
binders to sulfate attack is determined by applying several test methods. Results ofan investigation on sulfate resistance of ordinary Portland cement and limestone
powder replacing cement mortars, which were tested by the test methods ofweight loss, expansion, strength reduction, volume loss, and visual inspection withimage processing technique, are presented. It was observed that for NS solution,
expansion test is appropriate for performance evaluation of all ordinary Portland
cement and limestone powder replacing cement mortars. In case of MS solution,
both expansion and weight loss or volume loss or image processing technique areconsidered suitable to test limestone powder replacing cement mortars.
Keywords: sulfate resistance, limestone powder, expansion, weight loss, image
processing technique
1. INTRODUCTION
Sulfate attack on concrete is a culmination of a series of reactions that occur in thepresence of sulfate ions (mainly sodium and magnesium sulfate). Sulfate attack
manifests itself in the form of loss in strength, expansion, surface spalling, massloss, and eventually disintegration (Tikalsky and Carrasquillo, 1989). Many
laboratory tests were established to evaluate the sulfate resistance of concrete.
Although some of these methods have been adopted as standard test method by929

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Vietnamstandards organizations or they have become national codes, many test methods
are still not appropriate for some cases and being modified. Tests of the sulfate
resistance are usually performed by the determination of expansion of mortar bars
such as ASTM C452 and ASTM C1012. However, in magnesium sulfate
environment, different mechanisms can affect the concrete differently. Test
methods of ASTM may be good only to evaluate volume instability due to mainly
ettringite formation. Krammart and Tangtermsirikul (2004) suggested that theappropriate test methods for magnesium sulfate environment should also include
the strength reduction or weight loss test. There are currently no universally
accepted methods for testing overall sulfate resistance of concrete.
This study is aimed to identify the inadequacies of the presently used methods fortesting sulfate resistance of cementitious systems, and to propose properlaboratory tests for evaluating the sulfate resistance of mortars made from OPC1
and OPC5 cements and limestone powder replacing cements. The relative
resistance of mortars made from different binders to sulfate attack is determinedby applying several test methods such as expansion, weight loss, strength
reduction, volume loss, and visual inspection with image processing technique.
2. MATERIALS AND MIX PROPORTIONS
Ordinary Portland cement type 1 (OPC1), ordinary Portland cement type 5(OPC5), and limestone powder (LP) were used as materials in the experiment. LPwith mean particle size of 3.2 micron was provided by Surint Omya Chemical(Thailand). The chemical compositions of materials used are given in Table 1.
The mortar mixtures were made with a ratio by volume of sand to binder of 2.75.
Water to binder ratio was controlled at 0.40 and 0.55. LP replacement percentages
were 10 and 20% by mass of the total powder materials. The mix proportions
were systematically designated as shown in Table 2.
Mortar cube specimens (50x50x50 mm) and mortar bar specimens (25x25x285mm) were prepared in accordance with ASTM C109 and ASTM C1012,
respectively. Immediately, after casting, the molds were covered with plastic
sheets and the specimens were demolded at one day of age. After demolding, allbars and cube specimens were stored in a plastic tank of saturated limewater for
28 days and then exposed to the sulfate solutions. Sodium sulfate (NS) used inthis study contained 50g of NS dissolved in 1.0 liter of solution (SO42- of 33,800
ppm or 5% by weight of solution) whereas 42.36g of magnesium sulfate (MS)was used to prepare the magnesium sulfate solution in order to obtain the same
concentration of SO42- as that of the NS solution. The solutions were mixed 24
hours before use, and stored at a constant temperature of 30±2 oC. Volume ratio of
sulfate solution to specimens in a storage container was approximately 4 to 1. The
solutions were replaced every two months of exposure.
The measurements of expansion, weight loss, strength reduction, volume loss, andvisual inspection with image processing technique of mortar specimens wereconducted. Microscopic examinations were conducted on pastes with water tobinder ratio of 0.40 for all mix proportions. The investigation included
Thermogravimetric Analysis (TGA), Mercury Intrusion Porosimetry (MIP), XRay Diffraction (XRD) and Scanning Electron Microscopy with Back-Scatter
Electron Mode (SEM/BSE with EDX analysis).

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Table 1: Chemical compositions and physical properties of binders
Chemical Compositions (%)
SiO2
Al2O3
Fe2O3
CaO
MgO
SO3
Na2O
K2O
TiO2
P2O5
Free CaO
LOI

OPC 1

19.51
4.97
3.78
65.38
1.08
2.16
< 0.01
0.47
0.25
0.07
1.00
2.27
Physical Properties
Specific Gravity
3.12
2
Blain fineness (cm /g)
3,550
Mean diameter (µm)
15.41

OPC 5

LP

21.87
3.87
4.34
64.56
1.11
2.08
< 0.01
0.24
0.21
0.05
0.76
1.59

0.46
0.06
0.03
55.25
0.37
< 0.01< 0.010.01< 0.01
0.01
43.79

3.18
3,830
14.43

2.79
8,840
3.23

Table 2: Mix proportions of the tested mortar specimens
Mix

Mix Designation

1
2
3
4
5
6
7
8

M1-0.40
M1 90 LP10-0.40
M1 80 LP20-0.40
M5-0.40
M1-0.55
M1 90 LP10-0.55
M1 80 LP20-0.55
M5-0.55

Cement
Type
OPC 1
OPC 1
OPC 1
OPC 5
OPC 1
OPC 1
OPC 1
OPC 5

Mix proportion (ratio by weight)
Cement
LP
Water
Sand
1.0
0.40
2.75
0.9
0.1
0.40
2.75
0.8
0.2
0.40
2.75
1.0
0.40
2.75
1.0
0.55
2.75
0.9
0.1
0.55
2.75
0.8
0.2
0.55
2.75
1.0
0.55
2.75

3. TEST PROCEDURES
In this investigation, the measurements of expansion, weight loss, strength
reduction, volume loss, and visual inspection with image processing technique ofmortar specimens were conducted.
3.1 Expansion measurement
The expansion was measured on mortar bar specimens according to ASTM C1012.
The initial length of the specimens was measured after 28 days of curing insaturated lime water. Subsequently, they were placed in the sulfate solution andTest methods for evaluation of sulfate resistance of limestone powder replacing cement
Test methodsmortars
for evaluation of sulfate resistance of limestone powder replacing cement mortars

931

October
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Hanoi,Hanoi,
Vietnam0ctober
Vietnamthe length change was measured at the end of every 8 weeks of exposure. An
expansion value was obtained from the average of three specimens.
3.2 Weight loss measurement
The weight loss was determined on the mortar cube specimens and computed as
the difference between initial weight of the specimen after 28-day immersion inwater and weight of the specimen after immersion in sulfate solutions, comparedin % of the initial weight.
3.3 Strength reduction measurement
Strength reduction was calculated based on the compressive strength of mortar
cube specimens immersed in water compared to the compressive strength ofmortar cube specimens exposed in sulfate solution, in % of the strength immersed
in water.
3.4 Volume loss measurement
Volume loss, a new conceptual test, is introduced to help predict the surface
damage of concrete at early submersion ages. Usually, to be able to judge andcompare the degree of damage, long term submersion periods are required whileat early submersion ages, interpretation cannot be done. At the same time ofweight loss measurement, the mortar cube specimens were measured for volume
loss by a water displacement method. The volume of specimens was obtained byweighting the specimens in air and in water. The difference in weights ofspecimens could then be used to calculate the volume of specimens. A buoyancy
balance weighting was used to measure the apparent immersed weight.
3.5 Surface area loss measurement by image processing technique
Determination severity of the mortar cube specimens in MS solution (surface
deterioration) was evaluated by visual inspection. To bring the judgment ofdifferent observers into agreement, and to avoid variation in judgment from time
to time, the image processing technique was developed by adopting Saengsoy andTangtermsirikul (2010) previous work. The cube mortar samples were brought totake photos of their faces with sufficient resolution. The image size and quality ofthe photographs were adjusted for the sake of easiness to identify the damage
boundaries of the specimen as shown in Fig. 1. The areas of the damage
boundaries of the specimen were determined by computer software. The averagesurface areas of six faces of each specimen were determined. The surface area lossof cube specimens was calculated from the average of surface area of two
specimens. The surface area loss of each specimen was obtained from
Surface area loss (SAL), % = [(Sai – Sat) / (Sai)] x 100(1)

where Sat is surface area of the specimen after immersion in the sulfate solution
and Sai is surface area of the specimen after 28-day immersion in saturated lime
water before being exposed to sulfate solution.

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ICUS Report 73(a) Image of a specimen(b) Damage boundaries of a specimen
Figure 1: Determination of damage area of specimen
4. RESULTS AND DISCUSSION
4.1 Exposure in Na2SO4 solution
4.1.1 Expansion Results
Relationships between the expansion and period of immersion in NS solution of
OPC and blended cement mortar bar specimens with w/b of 0.40 and 0.55 areshown in Fig. 2. These data indicated that, for specimens placed in NS solution,
the expansion of OPC1 cement mortar was, as generally known, higher than thatof OPC5 cement specimen. Smaller quantity of C3A of OPC 5 cement (1.7%) thanthat of OPC1 (5.5%) leads to less amount of ettringite. At higher w/b (0.55), theeffect of composition of cement becomes more significant. For the specimens
made from limestone powder replacing cement, the expansion of 10% LP
replacing cement (M1 90LP10) mortar bar specimen was significantly larger thanthat of 20% LP replacing cement (M1 80LP20) mortar bar specimen but still
lower than that of the OPC1 mortar. This is partly because of lower Ca(OH)2 (CH)when comparing between the amount of CH in LP replacing cement specimens(P1 90LP10, P1 80LP20) and that of the OPC1 specimen (P1). Amount of
Ca(OH)2 at the age of 91 days by TGA analysis of OPC1 paste (P1), P1 90LP10,
and P1 80LP20 were 18.1%, 16.5%, and 14.8%, respectively. The incorporationof limestone also reduces the amount of C3A in the LP replacing cement.
M 1 -0.40
M 1 90 LP10-0.40

M 5 -0.40
M 1 80 LP20-0.40

2.50
5N

2.50
2.00

M 5 -0.55
M 1 80 LP20-0.55

5N

1.50

Expansion, %Expansion, %2.00

M 1 -0.55
M 1 90 LP10-0.55

1.50

1.00

1.00

0.50

0.50

0.00

0.00

-0.50

-0.50
0

200

400 600 800 1,000 1,200 1,400
Immersing time, day

0200

400 600 800 1,000 1,200 1,400
Immersing time, day(a) w/b = 0.40(b) w/b = 0.55
Figure 2: Relationship between expansion and period of immersion in NS
solution of OPC and LP replacing cement mortars with w/b of 0.40 and 0.55
Test methods for evaluation of sulfate resistance of limestone powder replacing cement
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0.08

0.06

35
0.060

0.058

0.064

30
Total Porosity, %Average pore size, %

0.07

0.05
0.04
0.03
0.02

25
20

26.52

23.63
20.60

15
10
5

0.01

0

0.00
P1

10%LP

P1

20%LP

(a) Average pore size

10%LP

20%LP

(b) Total porosity

Figure 3: Average pore size and total porosity at the age of 91 days by MIP
analysis of LP replacing cement pastes
From Fig. 3, the average pore size and total porosity of 10% and 20% LP
replacing cement paste were higher than that of OPC1 It is observed that the
expansion of the LP replacing cement specimens was less than that of OPC1
specimens. It can be concluded that the more content of LP, the larger size of porein cement matrix. This would be increased an available space of the cement
matrix for ettringite accommodation (Fig. 4), as presented by a good behavior inless expansion due to Na2SO4 attack.
4.1.2 Weight Loss Results
Fig. 5 presents the effect of type and content of binders on weight loss of mortar
cube specimens with w/b of 0.55 immersed in NS solutions for 1,300 days. It is
obvious from this figure that no significant weight loss in each mixture wasdemonstrated. Almost all specimens in NS solution still gained weight or had very
low weight loss although the test period had reached 1,300 days. These results do
not provide any useful information for evaluation of NS resistance as themechanism of NS attack is mainly the ettringite formation which results in
expansion rather than weight loss (Al-Amoudi, 1995).
2.0
5N, 1,300 days

Wt. Loss (%)

1.0

E

0.06
0.0
-0.13
-1.0

-0.54

-0.49

Weightgain-2.0

Mortar Mix es

Figure 4: SEM image of LP replacing
cement paste showing formation of
ettringite in void934

Figure 5: Weight loss in NS solution ofmortar cube specimens with w/b of 0.55
at 1,300 days of immersion

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4.2 Exposure in MgSO4 solution
4.2.1 Expansion Results
Fig. 6 shows the comparison of expansion in MS and NS solutions of LP
replacing cement mortars. The figures show that the expansion in MS solution ofthese specimens was higher than that in NS solutions when compared at the same
immersion period. This is contrast to the behaviors of other types of binder systemthat usually produce larger expansion in NS solution than in MS solution. This isbecause MS solution decreases the pH of the system. For the system with LP,
there occurred dissolution of CaCO3 from the limestone powder that contributed
to gypsum formation (Irassar et. al., 2003) and then increases expansion of thespecimens (see Eqs. (2) to (5)).
5N-0.55

1.50

5N-0.55

1.50

5M -0.55

M1 80 LP20

M1 90 LP10

1.00
Expansion, %1.00
Expansion, %5M -0.55

0.50
0.00

0.50
0.00

-0.50

-0.50
0

200

400

0

600 800 1,000 1,200 1,400
Immersing time, day

200(a) 10% replacement400

600 800 1,000 1,200 1,400
Immersing time, day(b) 20% replacement

Figure 6: Effect of type of sulfate on expansion of LP replacing cement mortars
with w/b of 0.55
4.2.2 Weight Loss Results
For MS solution, relationships between the weight loss and period of immersionof LP replacing cement mortar cube specimens is shown in Fig. 7. These data
indicated that, for specimens placed in MS solution, LP replacing cement
specimens showed equivalent in weight loss to that of the OPC5. In addition, theLP replacing cement with 20% LP gave smaller weight loss than the LP replacing
cement with 10% LP.
M 1 -0.40
M 1 90 LP10-0.40

5.0

M 1 -0.55
M 1 90 LP10-0.55

4.0

3.0
2.0
1.0
0.0

M 5 -0.55
M 1 80 LP20-0.55

5.0

5MWeight loss, %Weight loss, %4.0

M 5 -0.40
M 1 80 LP20-0.40

5M

3.0
2.0
1.0
0.0
-1.0

-1.0
0

200

400

600 800 1,000 1,200 1,400
Immersing time, day(a) w/b = 0.40

0

200

400

600 800 1,000 1,200 1,400
Immersing time, day(b) w/b = 0.55

Figure 7: Relationship between the weight loss and period of immersion in MS
solution of OPC and LP replacing cement mortars
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For system with limestone powder, the solubility of CaCO3 is a function of the pH
value. The MS attack is found to decrease the pH with higher dissolution of
CaCO3 as shown in Eq. (2) which contributes to gypsum formation as in Eq. (3).
The products which are magnesite in Eq. (4) and dolomite in Eq. (5), agreed with
Lee’s work (2007), can be formed in specimens with LP exposed to MS solution.
Formation of gypsum, magnesite, and dolomite results in less weight loss and lesssevere surface etching of the LP blended cement. The formation of magnesite anddolomite by MS attack determined by the XRD analysis was confirmed in Fig. 8.
It was found that more amounts of magnesite and dolomite presented in LP
cement paste specimens than in the OPC specimens. Another reason was that the
precipitation layer of calcite was found on the exposed surface of the LP cement
paste as shown by SEM image in Fig. 9. This layer helped delaying the ingress ofmagnesium ions into the paste.
Dissolving of

CaCO3

CaCO 3 s   Ca 2   CO 32 

(2)

Gypsum formation

Ca 2  SO 4 2  2H 2 O  CaSO 4  2H 2 O(3)Magnesite formation Mg 2  CO 3 2  MgCO 3
Dolomite formation



CaCO 3  Mg 2  Ca MgCO 3 2

Dolomite

0.11

10%LP

P1

0.37

Ca(CO)3
0.10

(5)

0.37

0.00
0.00

0.00



Magnesite
0.24

20%LP

(4)

0.20
0.30
0.40
The amount of produces, %0.50

Figure 8: Amount of magnesite anddolomite by XRD analysis

Ca(CO)3

Figure 9: SEM photograph of LP
cement paste showing the external layer
consisted calcium carbonate

4.2.3 Strength Reduction Results

Figure 10 shows results of the strength reduction of mortar cube specimens with
w/b of 0.55 made from various types of binder at 600 days of exposure in MS
solution. For mortar cube specimens replaced in MS solution, the strength
reduction of LP replacing cement mortars was lower than those of Type 1 andType 5 control cement mortars. The trend of change of the strength reduction andweight loss performance is similar in such a way that strength reduction of mortar
cube specimens increased along with the weight loss. However, a problem ofcompressive strength test for sulfate resistance evaluation is that it requires large
number of specimens throughout the test period since the tested specimens can not
be reused. In addition since damages occur on all surfaces, it is difficult to prepare
surfaces for compression test and also to estimate the actual cross sectional area
for compressive strength calculation

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50

Strength
reduction of
OPC5 specimen

Strength reduction, %

40
30
20
10
0

Mortar mixes

Figure 10: Strength reduction results of mortar cube specimens with w/b of 0.55 at
600 days of exposure in MS solution
4.2.4 Volume Loss Results
The test results of volume loss and weight loss of mortar cube specimens madefrom two cement types and replacing cements with limestone powder having w/bof 0.40 and 0.55, exposed in MS solution are shown in Fig. 11. In MS solution,
the trend of change of the two performances was similar. That was to say when
the weight loss of mortar cubic bar specimens increased, the volume loss also
increased. It is noted that the volume loss can be measured at the earlier test ageof submersion than the weight loss that the values of % volume loss are generally
much larger than those of the weight loss. For prolonged test, the weight loss
measurement is still recommended to be used to assess the sulfate resistancebecause it is easier to perform when compared to the volume loss.
M 1 90 LP10-0.40VL
M 1 90 LP10-0.55VL

6.5
5.5

M 1 90 LP10-0.40WL
M 1 90 LP10-0.55WL

6.5
5.5

5M

M 1 80 LP20-0.40WL
M 1 80 LP20-0.55WL

5M

4.5

Loss, %

Loss, %

4.5

3.5

3.5

2.5

2.5
1.5

1.5

0.5

0.5

-0.5

M 1 80 LP20-0.40VL
M 1 80 LP20-0.55VL

0

200

400

600 800 1,000 1,200 1,400
Immersing time, day(a) 10% LP replacing cement

-0.5

0

200

400

600 800 1,000 1,200 1,400
Immersing time, day(b) 20% LP replacing cement

Figure 11: Volume loss & weight loss of mortar cube specimens made from LP
replacing cements with w/b of 0.40 and 0.55 of exposure in MS solution
4.2.5 Visual Inspection Results
Fig. 12 shows the relationship between the surface area loss (SAL) and period of
immersion of OPC1, OPC5 and LP replacing cement mortar cube specimens with
w/b of 0.55 immersed in MS solution. This figure indicated that the LP replacing
cement mortar cube specimens performed relatively well after 1,360 days, with
Test methods for evaluation of sulfate resistance of limestone powder replacing cement
Test methodsmortars
for evaluation of sulfate resistance of limestone powder replacing cement mortars937

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamexcellent performance at a SAL lower than 10%. On the other hand, SAL of
OPC1 and OPC5 cement mortar cube specimens was the highest which was
similar to the case of weight loss results as mentioned before.
The results from Fig. 13 supported the use of visual inspection with image
processing technique as a method to assess the surface deterioration type of
sulfate attack. Visual inspection has provided a much earlier indication of thedeterioration than the weight loss test. At early submersion ages, all specimens
recorded increases in weight as presented in Fig. 13 but the visual inspection withimage processing technique could indicate surface deterioration at the SAL up to
1%. It was also observed that specimens with high SAL value, more than 1% loss
at the age of 240 days showed very low weight loss at the same exposure periodof 240 days (Fig. 13(a)), however they showed high weight loss in long term
period (Fig. 13(b)) and the two values, SAL at 240 days and % weight loss at longterm, had good correlation. Therefore, visual inspection with image processing
technique was very useful as it is possible to evaluate the surface deterioration
type of sulfate attack at the earlier period.
0

200

400

Immersing Time, day
600 800 1,000 1,200 1,400

0.0

SAL, %

5.0
10.0
15.0

5M

20.0

M1-0.55
M1 90LP10

M5-0.55
M1 80LP20

Figure 12: Relationship between the SAL and period of immersion in MS
solution of mortar cube specimens with w/b of 0.55
SAL<1%

SAL>1%
5M

3

SAL<1%

4
SAL%, at 240 days

SAL%, at 240 days

4

2
1

SAL>1%
5M

3
2
1
0

0
0

1

2

3
4
5
6
Wt. Loss%, at 240 days(a) 240 days

7

8

0

1

2

3
4
5
6
Wt. Loss%, at 1,360 days

78(b) 1,360 days

Figure 13: Relationship between the SAL at 240 days and weight loss at 2
exposure periods (240 days and 1,360 days) of immersion in MS solution of
specimens
Also, the choice of degradation measurement may lead to different conclusions
due to the multiple mechanisms of deterioration. Often a combination of multiple

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relevant indicators will be necessary. Therefore, only one method of measurement
may not be sufficient to characterise the degradation. Weight loss, for instance,
may be well used when no secondary products precipitate, otherwise it may be theresult of a combination of several phenomena. It is therefore more beneficial touse image processing technique to investigate the MS resistance of the specimen,
for the surface deterioration type.
5. PROPOSED RECOMMENDATIONS FOR SELECTINGMETHOD FOR SULFATE RESISTANCE EVALUATIONTESTFrom the obtained results of expansion and weight loss, it could be seen that incase of NS solution, expansion test is appropriate for performance evaluation ofordinary Portland cement and LP replacing cement mortars. In case of MS
solution, the relationship between expansion and weight loss of mortar specimens
in MS solution, is directly proportional for LP replacing cement mortars.
Therefore, for OPC and LP replacing cement specimens immersed in MS solution,
the suitable tests should be both weight loss or volume loss or image processing
technique and expansion. Based on the results of this study, the recommendations
for selecting laboratory test method for sulfate resistance evaluation of cementand LP replacing cement are proposed in Table 3.
Table 3: Proposed recommendations for selecting test method for sulfate
resistance evaluation
Type ofsulfate solution

Binder types

Sodium Sulfate

OPC and
LP replacing cement

Magnesium
Sulfate

OPC and
LP replacing cement

Recommendation forlaboratory test method

Expansion
Weight loss or
Image processing techniqueand Expansion

6. CONCLUSIONSThe study on sulfate resistance of mortars made from limestone powder replacing
cements indicated that the limestone powder replacing cement had advantages
over OPC1 cement in NS solution since it is less susceptible to the expansion due
to higher porosity which increased available spaces for ettringite deposition.
Weight loss measurement does not provide any useful information for evaluationof NS resistance as the mechanism of NS attack is mainly the ettringite formation
which results in expansion rather than weight loss. For mortars containing
limestone powder in MS solution, the MS decreased the system’s pH. Thereoccurred higher dissolution of CaCO3 from the limestone powder which
contributed to more gypsum formation as well as resulted in formation ofmagnesite and dolomite which mitigated the conversion of C-S-H to M-S-H andthen resulted in less weight loss and less severe surface etching of the specimens.
Test methods for evaluation of sulfate resistance of limestone powder replacing cement
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For surface deterioration type in MS solution, the weight loss of specimens
exposed to sulfate at early ages does not provide clear evaluation results of thesulfate resistance due to long period of weight gain while the strength reduction
method requires large amount of specimens and difficult to prepare the damaged
surface for the test. Visual inspection with image processing technique is useful tobe applied to observe the deterioration of specimens at early submersion ages. The
results obtained from the image processing technique also have good correlation
with the long term deterioration.
It was proposed that for specimens immersed NS solution, expansion test isappropriate for performance evaluation of ordinary Portland cement and LP
replacing cement mortar bar specimens. In case of MS solution, both expansion
and weight loss or volume loss or image processing technique are considered
suitable to test LP replacing cement mortars.
ACKNOWLEDGEMENT

This research was supported by the research funds from Srinakharinwirot
University, Siam Research & Innovation Co Ltd., and Construction and
Maintenance Technology Research Center (CONTEC) of Sirindhorn International
Institute of Technology, Thammasat University. The research is also partially
supported by the Higher Education Research Promotion and National Research
University Project of Thailand, Office of the Higher Education Commission, andNational Science and Technology Development Agency (NSTDA).
REFERENCES

Al-Amoudi, O.S.B., 1995. Performance of 15 reinforced concretes in magnesiumsodium sulphate environments, Construction and Building Materials, Vol. 9, No.3,
pp. 149-158.
Irassar, E.F., Bonavetti, V.L., Gonzalez, M., 2003. Microstructural study of
sulfate attack on ordinary and limestone Portland cements at ambient temperature,
Cement and Concrete Research, Vol.33, pp.31-41.
Krammart, P. and Tangtermsirikul S., 2004. Expansion, strength reduction andweight loss of fly ash concrete in sulfate solution, AJSTD Vol.21 Issue 4, pp. 373390.
Lee, S., 2007. Performance deterioration of Portland cement matrix due tomagnesium sulfate attack, KSCE Journal of Civil Engineering, Vol.11, pp.157163.
Saengsoy, W., and Tangtermsirikul, S., 2010. Determination of Mix Proportion ofHardened Concrete containing Fly Ash with Different Characteristics,
Proceedings of 4th ACF International Conference, Taipei, Taiwan, Tue-S4.1-05.
Tikalsky, P.J., and Carrasquillo, R.L., 1989. The effects of fly ash on the sulfate
resistance of concrete, Research Report 481-5, Center for Transport Research,
The University of Texas at Austin, Austin, Texas, USA, 317 pages.

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Hanoi towards 2030 - Substance flow analysis
supporting the planning process
Viet Anh NGUYEN1, Jan-Olof DRANGERT2, Manh Khai NGUYEN3, Thi Ha
NGUYEN4, Hans Bertil WITTGREN5 and Celeste ZIMMERMANN6
1
Associate Professor and Vice Director, Institute of Environmental Science andEngineering (IESE), Hanoi University of Civil Engineering, Vietnam.
vietanhctn@gmail.com
2
Associate Professor and Managing Director, Vatema AB, Stockholm, Sweden
3
Associate Professor and Vice Dean, Faculty of Environmental Science, Hanoi
University of Science,
Vietnam
4
Associate Professor and Head of Department, Environmental Technology
Department,
Hanoi University of Science, Vietnam
5
Associate Professor and Project Manager, Urban Water Management AB,
Linköping, Sweden
6
Master of Science, Division of Water and Environmental Studies,
Linköping University, Sweden
ABSTRACT
Vietnam is rapidly urbanizing and Hanoi is becoming a megacity. The current
population of Greater Hanoi, 6.6 million, is expected to increase by almost 50 %until 2030. Challenges faced by the city in terms of, e.g., water and wastewater
management, food and energy supply, as well as social infrastructure, are typicalfor developing cities. The Master Plan of Hanoi city to 2030, with a vision to 2050,
has just been completed (2011). It is therefore the right time to conduct a study onsustainable development solutions for the city, so as to propose efficient
preparation of detailed sector development plans. In the present study, substanceflow analysis of the crucial plant nutrient of phosphorus, and of organic “waste”(measured as COD), is employed to analyze the outcome of different scenario
assumptions concerning, e.g., population increase and development of newsatellite cities, changes in food habits, and different technologies for managementof organic waste products. Furthermore, the database with associated flow
calculations, supplemented with a user interface, is intended as a decision support
tool. This project has scanned what options there may be for a sustainable Hanoi
and the outcomes can be fed into the decision making process for the city
development at various levels.
Keywords: decision support tool, organic matter, phosphorus, substance flow
analysis, scenario.
1. INTRODUCTION
Limited global resources and increasing emissions push planners and societies todevelop more sustainable cities. Phosphorus (P) is an essential nutrient for plant941

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growth and food security, and it requires a holistic system approach to coordinate
P-flows between urban and rural areas. Agriculture dominates the ecologicalfootprints of phosphorus use and misuse, while urban demands from changing
diets and detergents impact flows and emissions to the environment.
In this article the future of phosphorus flows in the Greater Hanoi area in Vietnam
is analyzed from two perspectives. The linear flows with little or no recovery andrecycling of urban nutrients in agriculture and, alternatively, short loop flows
where most P-containing matter is recovered and brought back to soils for foodproduction. Both scenarios build on estimates in the ‘Master Plan of Hanoi city to2030, with a vision to 2050’ (Ministry of Construction - MOC, 2011). A
preliminary survey shows that P flows in Greater Hanoi is dominated by pig andrice production and detergents. These three flows are singled out for the analysis
of some scenarios.
2. MATERIALS & METHODSAs defined by Brunner and Rechberger (2004), Material Flow Analysis (MFA) is‘a systematic assessment of the flows and stocks of materials within a systemdefined is space and time’. In industrialized countries it has been used to help
identify and respond to emerging environmental problems (Montangero andBelevi, 2008), however it is also being increasingly applied in developing
countries, particularly in the context of environmental sanitation.
2.1 System definition
The system boundary of this study is the geographical limits of Greater Hanoi,
and the substances in focus are phosphorus and COD. This is an extension of thework done by Montangero in central Hanoi (Montangero, 2007). The work
published in this paper is limited to the results regarding phosphorus (P).
In MFA, processes are physical or conceptual spaces in which substances aretransformed, transported or stored. In this study, 19 different processes were
defined, and each was assigned a number from 1 to 25 (Table 1). As we modeled
the numbering system after Montangero (2007) and some of the processes were
not used in our system, some numbers are left blank. Additionally, someprocesses were further divided into sub-processes, which are indicated by a lower
case letter following the process number.
Table 1: List of processes and sub-processes used in the study
Process
Description
1
Inhabitants
2
On-site sanitation (a. Septic tank; b. Biogas latrine; c. Pit latrine; d.
Single or double vault latrine; e. Bucket latrine; f. Open defecation;
g. Urine diversion; h. Blackwater diversion)
3
Combined sewerage & drainage
4
Solid waste collection (a. Food waste collection; b. Sludge
collection; c. Excreta collection; d. Urine collection; e. Blackwatercollection and dewatering)

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5
6
7
8
9
10
11
12
13
14
15
16
17
18 - 2223
24
25

Water supply
Goods Exchange
Industry (a. Brewery; b. Distillery; c. Dairy; d. Bakery; e.
Slaughterhouse)
Handicraft industry (a. Cassava & arrowroot processing; b. Ricevermicelli production)(Not in use)
Composting
Waste site (a. Landfill; b. Open dump)
Livestock (a. Pig; b. Poultry; c. Cattle; d. Buffalo)
Aquaculture (a. Fish pond)
Crop (a. Rice; b. Maize; c. Vegetables; d. Soybean; e. Sweet potato;
f. Fruit)
Surface water
Soil/Groundwater
Atmosphere(Not in use)
Wastewater treatment plant
Biogas plant
Hazardous waste collection

2.2 Data Collection
The vast amount of data assembled for this study was collected in a variety ofways including interviews, observations, local documents and literature searches,and communication with experts. Most of the data is current (2009-2012) but
some data, particularly with respect to the P content of different products, may beolder. Due to the quantity of data assembled, it is not possible to cite references
for every data point included in the database given the limited space of thispublication.
Interviews and observations were the first stage of data collection. A total of 4
field studies were conducted; 3 in villages and 1 in an urban ward. Students at
Hanoi University of Natural Sciences and Hanoi University of Civil Engineering
composed questionnaires in Vietnamese and the local ward or village leader tookthem to various families to conduct the interviews. Local experts were also
consulted in some instances. Some information was also made available via
village reports and local industrial information since each commune submits anannual report and the industries issue yearly production figures. When
information was required that could not be obtained locally through an interview
or a local source, literature searches were conducted. The top priority was finding
data from Hanoi or other nearby provinces, but if that was not available, figures
were taken for Vietnam, South East Asia, or the world, in that order of preference.
Ultimately the data from the various sources were combined to create a single
database with separate information for the rural, urban and industrial sectors ofGreater Hanoi.

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2.3 Data management
Parameters are the raw data used for calculations. See Table 2 for examples. The
parameters are given identifying names in the following pattern:
y_name: y = a symbol indicating the class of parameter; name = a short
description of the parameter.
or, where applicable, y_P_name (where P indicates it is specific to phosphorus).
Table 2: Samples of the various classes of parameters
Parameter
Description
Parameter Classn_inhabitants
Number of inhabitants
Number (n)a_marketMarket area
Area (a)f_faecalsludge
Reported faecal sludge emptying
Frequency (f)factorm_P_greywater
P load in greywater
Mass flow (m)m’_SWbakery
Solid waste generation from
Rate of mass changebakery(m’)
q_rainRain
Volumetric flow (q)q’_WWslaughter Wastewater generation rate from
Rate of volumetrichousepig
pig slaughterhouseschange (q’)
c_P_groundwater Concentration of P in groundwater Concentration (c)r_fattener_pigs
Ratio between fatteners and total
Ratio (r)number of pigs
The mass flows of the substance(s) to and from each process are calculated byusing relevant parameters. The following notation was used to represent the mass
flow of substances between processes:
Pi-ii (where P= phosphorus, i= the initial process, and ii= the receiving process)For example P1-12a would represent the flow of phosphorus from process 1 toprocess 12a.
Parameters are used to write system equations for the mass flow variables. For
example:P1-12a = m_domesticFW * r_livestock_FW * c_P_domesticFW
multiplies the amount of domestic food waste (kg cap-1 yr-1) with the ratio fed tolivestock (-) and the P content in food (g P kg-1) to obtain the P flow in food waste
given to pigs (g P cap-1 yr-1).
Once the mass flows are known, the stock change rate of a given substance ineach process can be determined by finding the difference between the sum of the
inputs and the outputs. In this study the following notation is used to represent thestock rate of change:

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dM(Xi)/dt = Σinputs – Σoutputs (where X=the substance and i= the process).
For example, dM(P1)/dt would represent the stock change of phosphorus inprocess 1.
The database was constantly refined as questions or evidence of missing data
emerged. Flows were re-considered and the system altered to be more
representative of Greater Hanoi as new information came to light. If there seemed
to be problems with the calculations the relevant data was reassessed at a newliterature search was conducted to ensure appropriate data was used. Due to thewide scope of the project, specific uncertainties for each calculation were notdetermined. In the interest of simplicity the guideline of an acceptability of 10 %error in stock changes (Brunner & Rechberger, 2004) was taken as a reference
point.
2.4 Visualization and user interface
The software STAN (Vienna University of Technology, 2012) was used tovisualize the results. Weighted arrows are used to indicate the amount of mass ineach flow. Diagrams were created for each process individually, as well as
representations of larger parts of the system comprised of several processes.
To facilitate user interaction with the database, a user interface was constructed.
This allowed the user to vary the values of selected parameters to observe theeffects on the system. The interface is in a rudimentary form, but is continually
being improved with the hope that it can serve as a resource for city planners andpolicy makers.
3. RESULTS
The results presented below concern phosphorus (P) flows in Greater Hanoi (GH)related to a 2010 population of 6 617 900 inhabitants (HSO, 2011), and a
projected population of 9 135 500 inhabitants in 2030 (MOC, 2011). Focus is on
the large P flows associated with inhabitants’ consumption of rice, pork anddetergents. The ‘waste’ flows associated with these processes serve as planningsupport for future improved P management in GH.
First, assumptions and results for the ‘Present situation’ are presented, and thenassumptions regarding two scenarios, ‘Scenario 2030 Master Plan Linear’ and‘Scenario 2030 Master Plan Loops’. Both these scenarios involve an almost 50 %increase in population. Finally, the ‘Present situation’ and the two ‘Scenarios
2030’ are compared in terms of P flows.
3.1 Present situation
Current rice and pork consumption amounts to 137 kg and 24 kg cap-1 yr-1
respectively (VDD & UNICEF, 2011; The Pig Site, 2010), with a decreasing
trend for rice and an increasing trend for pork that mirrors the enhanced economic
development in Vietnam. Together with detergents, these two food items accountHanoi towards
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consumption trend. The improved human nutritional status in Vietnam is reflectedin the amount of protein that has increased from 45 g (1991) to 72 cap-1 d-1 (2008),
and thereof from animal origin from 10 g to 27 g cap-1 d-1 in the same period(FAO, 2013).
More than 90 % of urban inhabitants, and between 50 and 60 % of rural
inhabitants, have flush toilets connected to septic tanks (Nguyen V. A. et al.,2011). In urban and peri-urban districts, these septic tanks are mostly connected tothe city sewer (WSP, 2012). Only blackwater enters the septic tanks, which seems
to be a remnant from earlier direct collection of excreta. Greywater is usuallydischarged directly to sewers or waterways. Besides flush toilets, pit latrines ordouble vault latrines are the most common solutions in rural areas.
Today, three wastewater treatment plants treat 7 % of the effluent coming fromcore city area, while the remainder is discharged to waterways. Septic tanks aredesludged on average only every 6th year. Only 10 % of collected sludge iscollected by the urban environment company (URENCO) and brought to thelandfill or composted (Nguyen V. A. et al., 2011). The remainder is collected byother service providers who usually discharge the sludge illegally to fish farms,
landfills, or waterways, due to a lack of treatment infrastructure and poor
inspection. New high-rise office and apartment building connect their blackwaterto big septic tanks in the ground. Septic tank effluent and greywater is discharged
into combined sewer, not being treated in most of cases. Much of the polluted
effluent is used for irrigation in downstream areas. In the core city, 97 % of theover hundred lakes are eutrophic, of which 68 % are hyper-eutrophic (Hoang T. T.
H. et al., 2012).
Pig production and rice farming dominate P flows in agriculture. Farmers in the
Red River Delta typically grow three crops per year, spring rice from February toJune, summer rice from June to September, and a winter crop (often maize) from
October to January. The potential land area for growing winter crops is about
60 % of the rice area, but only 40 % of the rice area is currently cultivated withwinter crops (Tran T. S. et al., 2004). Good lowland farmers routinely produce 15
to 18 tonnes of grain per ha each year in a system that is traditionally communitybased, very labor-intensive, and involving much recycling of nutrients (Bray
1998). Farms are small, 0.1 – 0.5 ha and the population exceeds 2 000 people per
km2 in several provinces. Rice is mainly for local consumption (about 80 %). The
area planted with rice has remained about the same since a few decades, while asubstantial increase in yields is due to improved fertilization and expansion ofirrigated areas from 65 % to 75 % of rice fields (1990 to 2000) (Tran T. S. et al.,2004). Most other crops such as tubers, vegetables, maize etc. has also
experienced substantial increases in productivity (FAO, 2013).

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The flow chart in Figure 1 is a simplified system that accounts for the main flows
and connects urban and rural flows within GH.

Figure 1: Current important phosphorus flows (ton P yr-1) in Greater Hanoi
In Fig. 1, ‘I’ and ‘E’ represent import and export. Black arrows represent flows
mainly within GH. Grey arrows represent import flows to and export flows fromthe GH area. Numbers given at the bottom of process boxes show ‘sum of input sum of output’. If it is ‘0’, an unknown flow has been calculated as a difference
between known input and output flows, i. e., Out 2 (unknown) = In 1 (known) +In 2 (known) – Out 1 (known). In two process boxes, ‘1. Inhabitants’ and ‘12a.
Livestock - pigs’, inputs and outputs have been calculated independently.
The total feed need for pigs (input to ‘12a. Livestock - pigs’) is calculated fromdata regarding sows with piglets and fatteners. Eighty per cent of the food wastefrom rural inhabitants, and 20 % of the food waste from urban inhabitants (a totalof 267 ton P yr-1) is assumed to be given to pigs. All maize produced in GH is
assumed to be used as pig feed (247 ton P yr-1). The remaining required feed iscovered by import of commercial feed.
Of all pig manure, 66 % is applied on rice fields according to the ratio between
paddy rice area and total crop area (HSO, 2011). This results in an averageapplication of 40 kg P ha-1 yr-1 to a paddy rice area of 204 662 ha in GH (HSO,
2011). This amount of manure is in line with observations from the Red River
Delta, where farmers harvest two rice crops per year and apply 20-25 kg P ha-1
crop-1 (Tran T. S. et al., 2004). The authors also report that 32 kg P ha-1 ofcommercial fertilizers are applied annually. These figures are used to calculate
input to ‘14a. Crop - rice’.

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It is assumed that about 1/3 of the pig manure is first used for biogas production
prior to applying the slurry on crops (the biogas process is not shown in Figure 1).
The assumption is that no P loss occurs in the biogas process. Therefore, potential
losses will appear in the flow ‘Excess to soil/water’ from the ‘14a. Crop - rice’
process. This unknown flow is calculated as the difference between the known
other flows to and from the process.
Based on Swedish figures that the slaughter-weight of fatteners is 73.7 % of thelive weight, and that pork meat is 59 % of the slaughter-weight (Carlsson et al.,2009) gives that 737 ton P yr-1 is contained in pork meat. The P content of solid
waste from ‘7e. Slaughterhouse’ is calculated as the difference between known
flows.
The (net) export of pork from GH is calculated as the difference between the
production of pork from ‘7e. Slaughterhouse’ and the input of pork for
consumption to ‘1. Inhabitants’.
The P flow with rice from ‘14a. Crop - rice’ to ‘6. Goods exchange - rice’ iscalculated given a total rice yield of 1 125 016 ton yr-1 (HSO, 2011), whichcorresponds to 5.5 ton ha-1 yr-1, and assuming a P content in rice (excluding bran)of 1.15 g P kg-1 (USDA, 2012). Export (net) of rice is calculated in the same way
as pork export.
The P flow with food waste from ‘1. Inhabitants’ is calculated from an annual
generation of 37 kg cap-1 yr-1 (Co Loa Commune People’s Committee, 2009; Co
Loa Interview, 2011-10-11) and a P content of 2 g P kg-1 (Diaz et al., 1996). For
excreta and greywater, P loads are assumed to be 0.86 g P cap-1 d-1 (Nguyen V. A.,
2007) and 0.4 g P cap-1 d-1 (Büsser, 2006), respectively.
3.2 Scenario 2030 - Master Plan with linear P flows to water bodies andlandfills
The assumptions of the Master Plan 2030 deal with population increase, pattern of
new suburbs, full coverage of water and sanitation, etc. No goals for sustainabilityor environmental issues are provided. Therefore, this scenario calculation takes
into account an anticipated population increase of 42 % from 2010 to 9.14 million
inhabitants 2030 (Prime Minister Decision 1239/QD-Ttg, 2011). As a result, otherfactors vary accordingly: a 42 % increase in all flows in and out from the process‘1. Inhabitants’, and associated changes in import to/export from ‘6. Goods
exchange’. For rice, the population increase result in that some import will be
required to meet demand. In reality, such import may be avoided by increased
productivity and/or increased area for paddy rice cultivation. For pork, production
remains higher than local consumption, and there is still capacity to export porkmeat from GH.
3.3 Scenario 2030 – P loops to recover and apply P on agricultural soils
This scenario is derived from the following desired functional criteria: no P in
detergents, all organic solid waste generated in Greater Hanoi to be segregated,

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composted or digested to biogas, and the residues applied to farmland. The
available nutrients in human excreta are used for cereal production. No
eutrophication of rivers and lakes, and reduced import of commercial fertilizers.
In the ‘Scenario 2030 - Master Plan Loops’ the same population size as in theprevious scenario is assumed. Pork consumption per capita is assumed to double
from 24 to 48 kg cap-1 yr-1, and rice consumption to decrease with the sameamount, from 137 to 113 kg cap-1 yr-1. For pork, this corresponds to an annual
increase in consumption by 3.5 %, and for rice an annual decrease by 1 %. In thepast 10-year period, both the consumption increase for pork and the decrease forrice have been larger, so the above assumption may be considered conservative.
Detergents will be phosphate-free. Furthermore, P-rich waste flows will berecycled: (i) human excreta to arable land after proper treatment for hygienic
purposes; (ii) solid waste from slaughterhouses to arable land, probably as aslurry after biogas production, and; (iii) food waste will continue to be recycled as
pig feed, as is currently common in rural areas, but, in the context of increasing
urbanization, also be used for biogas production and the resulting slurry recycled
to arable land.
3.4 Comparison of Present situation and the two scenarios for 2030
The calculations of flows in the two scenarios are presented in Table 3, and builds
on the flow chart in Figure 1. The figures in the column ‘Present situation’ repeats
the data in Figure 1. The column ‘Scenario 2030 – Master Plan Linear’ presents
revised data due to the population increase.
The column ‘Scenario 2030 – Master Plan Loop’ presents data resulting fromrecycling measures and changed diet. The total input of P to ‘1. Inhabitants’ will
decrease primarily due to the phasing out of P in detergents, and consequently the
P flow with greywater will decrease dramatically. The P flows associated withfood waste and excreta will increase somewhat, since the P-content of pork ishigher than that of rice. However, even without changes in pork production, theincreased consumption still allow for some export, and the decrease in riceconsumption results in that no import is be needed.
The demand of P inputs for rice production is shown in the lower four rows ofTable 3. The loops scenario can reduce demand for commercial fertilizers by
about 4 300 ton P yr-1. in comparison with the linear scenario. This reduction ispossible thanks to recycled P from food waste (336 ton P yr-1) and human excreta(3 026 ton P yr-1) from ‘Inhabitants’ and waste from slaughterhouses (949 ton Pyr-1) can replace imported commercial fertilizers.
Table 3: Comparison of P flows for the present situation and the two scenarios for2030 (ton P yr-1).
P flows
Present
Scenario 2030 Scenario 2030
situation- MP Linear- MP Loops
Inhabitants – In
Pork
243
345
691
Rice
1 039
1 476
1 219
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October
2013, Hanoi,
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Other food
Inhabitants – Out
Food waste
Excreta
Greywater
Goods exchange, pork – Out
Pork (to Inhabitants)
Pork (Export)
Slaughterhouse – Out
Solid waste
Livestock, pigs – In
Food waste
Goods exchange, rice – In
Rice (Import)
Goods exchange, rice – Out
Rice (to Inhabitants)
Rice (Export)
Crop, rice – In
Commercial fertilizer(Import)Biogas slurry (fromInhabitants, Food waste)
Excreta (from Inhabitants)
Biogas slurry (from
Slaughterhouse, Solid
waste)

968
1 165

1 374
1 654

0
1 654

491
2 077
1 141

698
2 951
1 621

715
3 026
246

243
494

345
392

691
47

949

949

949

267

379

379

0

182

0

1 039
255

1 476
0

1 219
74

6 549

6 549

2 238

0

0

336*

0
0

0
0

3 026
949

* The difference between total generation of food waste, 715 ton P yr-1, and foodwaste fed to pigs, 379 ton P yr-1.
A further 1 374 ton P yr-1 can be saved by using P-free detergents. The loops
scenario represents a win-win situation with reduced nutrient pollution of surface
and groundwater by discharges of P from wastewater outlets and landfills. This
environmental debt in the case of linear flows is a hidden cost in today´sdiscussion, but must be included in a sustainability calculation.
In addition to those savings it is reasonable to assume that increased foodefficiency in pig production and better P management in crop production candecrease the two largest P flows in Figure 1: import of commercial feed and theexcess of P to soil/water, where the latter is probably lost to water to a large
degree.
4. DISCUSSIONSUp to now, trends to manage P-containing matter in urban flows have become
more and more linear. Previous recycling of P-rich human excreta and food waste
to enrich agricultural soils has been replaced by waste discharges to water bodies

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and landfills. The huge increase in use of P in agriculture has been met byimported commercial fertilizers and animal feed. The previously strong nutrient
link between urban and rural areas in Greater Hanoi is fading away.
Anticipated global scarcity of virgin P and nutrients more generally points to theneed to reduce wastage and increase recycling (Cordell et al., 2009). A ban on P
in detergents will reduce demand in GH by more than 1 000 ton P yr-1, which is of
the same magnitude as 20 % of the imported commercial fertilizers in 2010. The
detergent manufacturers can easily introduce alternative washing compounds, e.g.,polycarboxylates as have been done in other countries (EU, 2012). A great benefit
is that eutrophication of water bodies will be reduced when there is less P in thegreywater fraction.
The population increase requires new homes to be constructed, and these could beaffordably built to facilitate recovery of nutrients. The infrastructure could bedesigned to transfer recovered P to farmland. Retrofitting existing houses would
take longer and gradually be achieved as retrofitting is due anyway. The economic
value of P, and more so of nitrogen, in the now wasted nutrient resources can pay
for the transport of recovered nutrients to farmland (Jönsson et al., 2012).
By sorting food and other organic waste and turn it to compost material, recycling
human waste and slaughterhouse waste to farmland, and banning P in detergents,
some 5 700 ton P yr-1 can be saved in 2030. Thereby, toxic emissions fromproducing mined P and transport it to Vietnam will be reduced accordingly (Wissa,
2006).
The potential option to save on P by not shifting to a diet with more meat anddairy products would require other policy measures. Firstly, a shift requires that
consumers have the information that meat and milk are P-inefficient methods toaccess building blocks for the human body. Secondly, the environmental costs
accruing from leakages are high. Such negative factors must be balanced withpositive aspects such as improved status and time-saving through access to easyto-prepare meat-based food.
This article has presented some examples of calculations that can be made basedon the decision support tool currently under construction. Work will proceed bycompleting the data base concerning both P and COD, and by development of auser interface to allow user-friendly access to calculation of different scenarios.
ACKNOWLEDGEMENTThe Paper was prepared based on the study results under the Sida PDC projectcoded AKT-2010-071: Contributions towards more equitable and sustainable
South Asian Cities - The case of Hanoi towards 2030. Contributions to the study
were made by the paper authors, and the other team members including Karin
Tonderski, Nguyen Thi Anh Tuyet, Do Hong Anh, Nguyen Phuong Thao, Nguyen
Tuan Linh, Bui Thi Thuy, Hoang Minh Trang, Ngo Van Anh, Nguyen Minh
Phuong, Pham Hoang Giang, Nguyen Phuong Hong. Special thanks are delivered

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Vietnam
October
2013, Hanoi,
Vietnamto all research team members, leaders and staff of related organizations who wereinvolved in the study, providing valuable expertise and information.
REFERENCES
Bray, F., 1998. A stable landscape? Social and cultural sustainability in Asian ricesystems. In: Dowling, N. G., Greenfield, S. M., Fischer, K. S. (editors).
Sustainability of rice in the global food system. Pacific Basin Study Center &International Rice Research Institute (IRRI), Davis (California, USA) & Manila(Philippines), pp. 45-66.
Brunner, P. H. and Rechberger, H., 2004. Practical Handbook of Material Flow
Analysis. Lewis Publishers, CRC Press LLC, Boca Raton (Florida, USA).
Büsser, S., 2006. Characteristics of domestic wastewater flows in urban and periurban households in Vietnam. ETHZ Practical Training Report. Eawag: Swiss
Federal Institute of Aquatic Science and Technology & Sandec: Department of
Water and Sanitation in Developing Countries, Duebendorf (Switzerland).
Carlsson, B., Sonesson, U., Cederberg, C. and Sund, V., 2009. Livscykelanalys(LCA) av svenskt ekologiskt griskött (Life Cycle Analysis of Swedish Organic Pig
Meat). SIK Report No. 798, SIK - the Swedish Institute for Food andBiotechnology, Gothenburg (Sweden). In Swedish.
Co Loa Commune People’s Committee, 2009. Annual report of Co Loa commune.
In Vietnamese.
Cordell, D., Drangert, J.-O. and White, S., 2009. The story of phosphorus: Global
food security and food for thought. Global Environmental Change, 19, 292–305.
Diaz, L. F., Savage, G. M., Eggerth, L. L. and Golucke, C.G., 1996. Solid waste
management for economically developing countries. International Solid Waste
Association & CalRecovery Inc., Concord (California, USA).
EU, 2012. Regulation (EU) No 259/2012 of the European parliament and of thecouncil of 14 March 2012 amending Regulation (EC) No 648/2004 as regards theuse of phosphates and other phosphorus compounds in consumer laundry
detergents and consumer automatic dishwasher detergents. Official Journal of theEuropean Union 30.3.2012.
FAO, 2013. FAO Annual Report 2013. Food and Agricultural Organization. Rome
(Italy).
HSO (Hanoi Statistical Office), 2011. Hanoi Statistical Yearbook 2010. Hanoi
Statistical Office, Hanoi (Vietnam).
Hoang Thi Thu Huong, Ly Bich Thuy, Pham Thu Phuong and Doan Thi Thai Yen,
2012. Eutrophication in the lakes of Hanoi discovered by water quality index andchlorophyll-A indicator. Journal of Science and Technology (Vietnam Academy of
Science and Technology), Vol. 50, No. 1 C.
Jönsson, H., Hallin, S., Bishop, K., Gren, I.-M., Jensen, E. S., Rockström, J.,
Vinnerås, B., Bergkvist, G., Strid, I. and Kvarnström, E., 2012. Många skäl att
återvinna mer fosfor (Several reasons to recover more phosphorus). Dagens
Nyheter, 2012-08-03. In Swedish.

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Prime Minister’s Decision 1239/QD-Ttg, dated 26 July 2011. Decision on
approval of General Master Plan for construction of Hanoi Capital to 2030, , andwith the vision to 2050 (in Vietnamese).
Montangero, A., 2007. Material Flow Analysis: A tool to assess material flows forenvironmental sanitation planning in developing countries. Eawag: Swiss Federal
Institute of Aquatic Science and Technology & Sandec: Department of Water andSanitation in Developing Countries, Duebendorf (Switzerland).
Montangero, A. & Belevi, H., 2008. An approach to optimise nutrient
management in environmental sanitation systems despite limited data. Journal ofEnvironmental Management, 88, 1538–1551.
Nguyen Viet Anh, 2007. Be tu hoai & be tu hoai cai tien (Septic tank andimproved septic tank). Construction Publishing House, Hanoi (Vietnam). In
Vietnamese.
Nguyen Viet Anh, Nguyen Hong Sam, Dinh Dang Hai, Nguyen Phuoc Dan, Bui
Xuan Thanh, 2011. Landscape Analysis and Business Model Assessment in Fecal
Sludge Management: Extraction & Transportation Models in Vietnam. Study
report. For the Bill and Melinda Gates Foundation, USA.
Tran Thuc Son, Nguyen Van Chien, Vu Thi Kim Thoa, Dobermann, A. and Witt,C., 2004. Site-specific nutrient management in irrigated rice systems of the Red
River Delta of Vietnam. In: Dobermann, A., Witt, C. and Dawe, D. (editors)
Increasing Productivity of Intensive Rice Systems Through Site-Specific Nutrient
Management. Science Publishers, Inc. & International Rice Research Institute(IRRI), Enfield (New Hampshire, USA) & Los Baños (Philippines), pp. 217-242.
The Pig Site, 2010. Viet Nam - Growth in Pork Meat Consumption Leads toOpportunities
forUS
Exporters.
Available<http://www.thepigsite.com/articles/3208/viet-nam-growth-in-pork-meatconsumption-leads-to-opportUnities-for-us-exporters> [Accessed 16 April, 2013].
USDA (U.S. Department of Agriculture, Agricultural Research Service), 2012.
USDA National Nutrient Database for Standard Reference, Release 25.
Available: <http://www.ars.usda.gov/ba/bhnrc/ndl> [Accessed 16 April, 2013].
VDD & UNICEF (Vien Dinh Duong & United Nations Children's Fund), 2011. A
review of the nutrition situation in Vietnam 2009-2010. Medical Publishing House,
Hanoi (Vietnam).
Vienna University of Technology, 2012. STAN (subSTance flow ANalysis)
software. Available: <http://www.stan2web.net> [Accessed 16 April, 2013].
Wissa, A. E. Z., 2006. Phosphogypsum disposal and the environment. Ardaman &Associates
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Available:<http://www.fipr.state.fl.us/pondwatercd/phosphogypsum_disposal.htm>[Accessed 31 August, 2013].
WSP (Water and Sanitation Programme), 2012. Economic Assessment of
Sanitation Interventions in Vietnam. A six-country study conducted in Cambodia,
China, Indonesia, Lao PDR, the Philippines and Vietnam under the Economics ofSanitation Initiative (ESI). Water and Sanitation Programme (WSP) Technical
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Comparisons nitrogen removal capacities
by anammox process using
different biomass carriers
TRAN Thi Hien Hoa1, LUONG Ngoc Khanh2, and Kenji FURUKAWA3
1National University of Civil Engineering (NUCE)
thhoadhxd@yahoo.com
2
Vietnam Water And Environment Investment Corporation (VIWASEEN)
3
Furukawa Consulting Company for Water Environment (FCW)ABSTRACTThe using of biomass carriers is preferred for the cultivation of slowly growing
anammox sludge. In this study, three types of PVA (polyvinyl alcohol) gel-bead,
MC (malt ceramic) and PE (polyethylene) sponge were selected as biomass
carriers for anammox sludge and applied in different reactors. The objective of
this study is to compare the nitrogen removal capabilities of anammox processusing PVA, MC and PE sponge as different biomass carriers. PVA gel-beadbiomass carrier was used in a fluidized-bed reactor (FBR) (called PVA reactor).
MC materials with two different sizes of d=3-5 mm and d=10-15 mm wereapplied in two fixed-bed reactors (called MC1 and MC2 reactors). PE spongematerial was selected in fixed-bed reactor (called PE sponge reactor). PVA
reactor was operated for 617 days with maximum removal rates of ammonium
and total nitrogen were 1.5 and 3.0 kg N/m3/day, respectively. MC1 and MC2
reactors were implemented for 368 days and 280 days, respectively. The T-N
removal rates of MC1 were increased stepwise from 0.6 to 3.1 kg N/m3/day fromthe days 187 to 315 while the T-N removal rate of MC2 obtained similarly to theresults of MC1 with 0.7 to 3.1 kg N/m3/day from the days 146 to 230. PE sponge
reactor was operated continuously and T-N removal rate of 2.8 kg N/m3/day was
obtained after 240days of operation. In addition, T-N removal rate of 2 kg
N/m3/day was obtained after short operational time of 140 days for PE sponge
reactor, in comparisons with the T-N removal rate of 2 kg N/m3/day for PVA
reactor, MC1 and MC2 over longer operational time of 546 days, 265 days and
185 days, respectively.
Keywords: anammox, biomass carrier, malt ceramic, MC, polyvinyl alcohol, PVA
gel beads, polyethylene, PE sponge, fixed-bed reactor, fluidized-bed reactor, FBR,
NH4-N, NO2-N, T-N.
1. INTRODUCTION
The traditional nitrification and denitrification processes for nitrogen removal has
been researched widely. However, more economical considerations using
shortcuts in the nitrification-denitrification process, i.e., Anaerobic Ammonium

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October
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VietnamOxidation (anammox), was much attention. This new process is combined with
the nitritation step, the remaining ammonium and the converted nitrite from
nitritation will be oxidized to dinitrogen gas under anoxic conditions with nitrite
as the electron acceptor (Mulder A. et al., 1995; Strous M. et al., 1999a). This
autotrophic process allows over 50% of the oxygen to be saved and no organiccarbon source is needed (Jetten M. S. M. et al., 1999). The anammox process cancontribute significantly to the nitrogen removal from wastewater with low carbon
content (Van de Graaf A. A. et al., 1996). In addition, the sludge production was
negligible (Fux C. et al., 2002). Therefore, anammox process is a promising andlow-cost alternative of removing nitrogen from wastewater (Strous M. et al.,1997a; Strous M. et al., 1997b; Van de Graaf A. A. et al., 1995).
The stoichiometry of the anammox reaction was determined based on massbalance over anammox enrichment cultures, as follows (Strous, M. et al., 1998):
NH4+ + 1.32 NO2- + 0.066 HCO3- + 0.13H+ 
1.02 N2 + 0.26 NO3- + 0.066 CH2O0.5N0.15 + 2.03 H2O (1)The slow grow rate of anammox bacteria with a doubling time of around 11 days
(Strous, M. et al., 1998) required long cultivation for getting enough amount of
anammox sludge. Consequently, the application of different carrier material using
anammox process is a challenge and the study about the appropriate materials is
paid much attention.
In this study, the first experiment was set-up by using PVA-gel beads as biomass
carriers for anammox sludge in FBR (called PVA reactor). PVA-gel beads haveporous microstructure that allows for microorganisms to penetrate and colonize
throughout the gel material, thus providing favorable conditions for retention andcultivation of slowly growing anaerobic microorganisms (Rouse J.D. et al., 2005).
An upflow column reactor using non-woven biomass carrier (Furukawa K. et al.,
2002; Furukawa K. et al., 2003; Rouse J.D. et al., 2003) and packed-bed reactor
using PVA gel beads(Rouse J.D. et al., 2005) were established. However, influent
medium for these reactors was not mixed completely. Therefore, anammox
bacteria are inhibited easily by high nitrite concentration (more than 0.1 g N/L)
(Strous, M. et al., 1999b) at bottom of reactor. Consequently, the new fluidized
bed reactor (FBR) was designed to mix substrate completely by recycling
wastewater to dilute the influent medium and overcome inhibition for anammox
bacteria at bottom of reactor. In addition, the surface area of PVA-gel beads iscontacted better in fluidized-bed condition than in packed-bed condition and good
release nitrogen gas. In the second experiment, MC materials with two different
sizes of d=3-5 mm and d=10-15 mm were applied in two fixed-bed reactors (sizeof d=3-5 mm called MC1 reactor; size of d=10-15 mm called MC2 reactor) of thesame configuration. MC is produced from beer barley husk and beer dregs. The
raw material of the beer dregs is dried and molded in to cylindrical shapes, which
are carbonized and crushed to different sizes. In addition, manufacturing processof MC material does not require chemicals. Therefore, MC material is natural
product and low cost which is possible to reduce nitrogen removal cost. PE
sponge is also effective biomass carrier material with the large pore diameter.
Hence, PE sponge was selected as biomass carrier in a fixed-bed reactor (called
PE sponge reactor) for nitrogen removal by the anammox process in the third
experiment. The objective of this study is to compare the nitrogen removal
capacities by anammox process using polyvinyl alcohol (PVA) gel beads, malt
ceramics (MC) and polyethylene (PE) sponge as different biomass carriers.

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2. MATERIALS AND METHODS
2.1 Experimental set-up in laboratory scale
The designed parameters and scheme diagrams for 4 reactors using PVA, MC andPE sponge are shown in Table 1 and Fig. 1, respectively.
Nitrogen gas

controller

Pre column

Effluent outlet

Nitrogengas bag

Water seal
controller

Recycling pipe

Port 1

Effluent outlet

Peristaltic pump

Water seal
MCmaterial

Effluent
tank
Influent
tank

Influent
inlet

Recyclingpump

Influent
tank

Port 1

Peristaltic
pump
Effluent
tank

Figure 1: Schematic diagram of the reactors with differrent
biomass carrier materials
Table 1: Designed parameters for 4 reactors
Parameters

PVA reactor

Type of reactor
Total reactor volume (L)Reaction zone volume (L)Clarification zone volume (L)Free zone volume (L)Diameter of reactor (cm)Height of reaction zone (cm)MC1
andMC2 reactors
Fluidized-bed Fixed-bed
4.06
1.62
2.15
0.65
1.4
0.34
0.51
0.31
7.4
7.1
50.0
16.5

PE sponge
reactorFixed-bed
2.90
2.60
0.30
9.0
41.0

2.2 Physical characteristics of different biomass carriers
Table 2: Physical characteristics of PVA-gel, MC and PE sponge
Characteristics
Shape
Pore diameter
Size
Porosity
Specific gravity
Material

PVA gelSphere10 – 20 µm
3.5-4 mm90%
1.025 g.cm-3
Polyvinyl alcohol

MC
Grain
2.17 x 10-3 µm
3-5 mm; 10-15 mm
1.96 g.cm-3
Charcoal

PE sponge
sheet
1060 µm
10 mm (thickness)
96%
0.995g.cm-3
polyethylene

Comparisons nitrogen removal capacities by anammox process using different biomass
Comparisonscarriers
nitrogen removal capacities by anammox process using different biomass carriers

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Polyvinyl
alcohol(PVA) gel beads
PVA-gelbeads
Diameter is 4 mm (Fig.
2a).
They
are
hydrophilic and have aporous diameter of 10
to 20 μm in (Fig. 2b).

Malt ceramic (MC)Two different sizes of
MC material were 3-5mm and 10-15 mm asshown in Fig. 3. This
material has a porous
microstructure with anaverage porous diameterof 2.17 x 10-3 µm.
Polyethylene(PE)spongePE sponge material isshown in Fig. 4a withaverage porous diameterof 1060 µm. PE spongematerial is soft hence it is
supported by frame asshown in Fig. 3b.

Figure 2: PVA-gel bead.
a. Origianl PVA-gel bead; b. Environmental ScanningElectron Micrograph (ESEM) of microstructure on thesurface of an original PVA-gel bead. Bar indicates 10 μm

Figure 3: Malt ceramic. a. Size of 3-5 mm; b. Size

Figure 4: PE sponge material.
a. Original PE sponge material; b PE spongematerial frame

As shown in Table 2, the porosities and other physical characteristics of thesebiomass carriers are very different. The pore diameter and porosity of PE spongematerial are largest and highest in comparisons with the porous diameter andporosity of PVA gel and MC materials. Only PVA gel could be fluidized in waterowing to light specific gravity and sphere shape. MC is cheap material because
MC is utilized and carbonized from the beer dregs and manufacturing process
does not require chemicals. Therefore, this one is cheap material in comparisonswith PVA gel and PE sponge.
2.3 Seed sludge
The cultivated PVA-gel beads used for the PVA reactor originated from aanammox packed-bed reactor. Total volume of PVA-gel beads was 0.8 L in phase
1 which included 0.7 L of cultivated PVA-gel beads and 0.1 L of new PVA-gel
beads. In phase 2, 0.2 L of cultivated PVA-gel beads were added for a total PVAgel volume of 1 L. For MC1 and MC2 reactors, 0.65 g of anammox sludge takenfrom a nonwoven reactor was seed sludge in each reactor. For PE sponge reactor,
1.2 g of anammox sludge taken from the nonwoven reactor was also seed sludge.

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2.4 Synthetic wastewater
Synthetic wastewater was prepared by adding ammonium and nitrite in the formsof (NH4)2SO4 and NaNO2, respectively to the mineral medium. Tap wateroriginating groundwater was used for the preparation of this synthetic wastewater.
Table 4: Composition of synthetic wastewater
Composition
Concentration(NH4)2SO4 (mgN/L)
Variable (25-300)
NaNO2 (mgN/L)
Variable (25-300)
KHCO3 (mg/L)
125.1
KH2PO4 (mg/L)
54.4
FeSO4.7H2O (mg/L)
9
EDTA (mg/L)
5
Trace element solution I (mg/L): CaCl2.2H2O 700,
MgSO4.7H2O 500
Trace element solution II (mg/L): CuSO4.5H2O 0.25,
ZnSO4 .7H2O 0.43, CoCl2.6H2O 0.24, MnCl2.4H2O 0.99,
NaMoO4.2H2O 0.22, NiCl2.6H2O 0.19, NaSeO4.10H20
0.11, H3BO4 0.014
2.5 Operational conditions for 4 reactors using PVA, MC and PE sponge asbiomass carriers
Influents for 4 reactors using PVA, MC and PE sponge as biomass carriers were
fed in up-flow mode using a peristaltic pump (Eyela Co., Ltd., Tokyo). The
reactor temperatures were maintained at 33oC to 35oC, controlled thermostaticallywith an external ribbon-heating element. Dark conditions were maintained using
black vinyl sheet enclosures. Small styrafoam balls were placed in the feedstorage tank to retard oxygen transfer to the synthetic wastewater. In addition,
purging with nitrogen gas was used on a daily basis to keep dissolved oxygen
levels in the influent below 0.5 mg/L. Influent pH levels were 7.2 to 7.5 without
adjustment.
Table 5: Operational parameters for 4 reactors using PVA, MC and PE sponge asbiomass carriers
Parameters
PVA reactor MC1 and MC2 PE
spongereactors
reactor
HRT (h)16- 3
12 - 324 - 4
Flow rate (L/d)
3.2 - 17.2
1.3 - 5.2
2.6 - 15.6
Influent NH4-N/NO2-N 25-300/2525-275/25-275
30-200/30-200
concentration (mg N/L) 300
2.6 Chemical analyses
Ammonium concentrations were measured by the phenate method using orthophenylphenol as a substitute for liquid phenol (Kanda J., 1995). In accordanceComparisons nitrogen removal capacities by anammox process using different biomass
Comparisonscarriers
nitrogen removal capacities by anammox process using different biomass carriers959

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamwith Standard Methods (APHA, AWWA, WEF, 1995), nitrite concentrations
were estimated by the colorimetric method (4500-NO2- B) and nitrate by the UV
spectrophotometric screening method (4500-NO3- B). Nitrite was determined tohave an interfering response in the nitrate UV screening method of 25% of thenitrate response on a nitrogen weight basis, thus results were corrected by
calculation. Levels of pH were measured by using a Mettler Toledo-320 pH meterand DO was measured by using a DO meter (D-55, Horiba).
3. RESULTS AND DISCUSSION
3.1 Influent and effluent T-N concentrations and T-N removal efficiencies for
4 reactors using PVA, MC and PE sponge as biomass carriers
InfT-N_PVA

EffT-N_PVA

InfT-N_MC(3-5mm)

EffT-N_MC(3-5mm)

T-N Removal Efficiencies (%)

T-N concentrations (mg/L)

Figs. 2 and Fig. 3 present
InfT-N_MC(10-15mm)
EffT-N_MC(10-15mm)
InfT-N_PEsponge
EffT-N_PEsponge
the changes in influent and700
effluent T-N concentrations
600
and
T-N
removalefficiencies for 4 reactors
500
using PVA, MC and PE
400
sponge as biomass carriers.
For
PVA
reactor,300
throughout phase 1 (the first200
364 days) influent andeffluent T-N concentrations
100
were 300-600 mg/L and 50150 mg/L except during
0
0
100
200
300
400
500
600
system upsets, respectively.
Time (days)
AverageT-NremovalFigure 2: Changes in influent and effluent T-N
efficiencies were about 77%.
concentrations for different reactors
In phase 2 from day 365 today 564, average T-N
T-N RE_PVA
T-N RE_MC(3-5mm)
T-N RE_MC(10-15mm)
T-N RE_PEsponge
100
removal efficiencies wereabout 75%. In phase 2 from80
day 565 to 617, T-N
removal efficiencies were60
about 70% with influent TN concentrations ranged
40
between 550-500 mg/L andeffluent T-N concentrations
20
were high from 120 and 200
mg/L. These data were0lower than results in phase 1
0
100
200
300
400
500
600
Time (days)
and the initial period of
Figure 3: Changes in T-N removal
phase 2 due to the shortefficiencies for different reactors
HRTs of 3.5 and 3 h.
For MC1 and MC2 reactors,
influent T-N concentrations were changed from 100 mg N/L to 500 mg N/L. With
HRT of 12 h and influent T-N concentrations of 100-400 mg/L, average T-N

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removal efficiencies of MC1 reactor were 73% with effluent T-N concentrationsof 10-175 mg/L in the first 163 days and average T-N removal efficiencies of
MC2 reactor were higher of 87% with effluent T-N concentrations of 10-140
mg/L in the first only 23 days. With HRT of 10 h to 3.5 h and influent T-Nconcentrations of 300 mg/L, average T-N removal efficiencies of MC1 reactor
were 76% (next 100 days) with effluent T-N concentrations of 40-90 mg/L. With
HRT of 10 h to 3.5 h and influent T-N concentrations of 350-200 mg/L, average
T-N removal efficiencies of MC2 reactor were 74% (next 150 day) with effluent
T-N concentrations of 40-120 mg/L. With HRT of 3h and influent T-Nconcentrations of 200-450 mg N/L, average T-N removal efficiencies of MC1
reactor and MC 2 reactor were similarly of 78% (35 days) and 79% (40 days),respectively. However, with HRT of 3h and influent T-N concentrations of 500550 mg/L, the average T-N removal efficiencies of the both MC1 and MC2
reactors were lower of 74% (69 days) and 73% (67 days) than before. The reason
was due to the high influent T-N concentrations under short HRT of 3 h.
For PE sponge reactor, influent T-N concentrations were increased from 60 to 300
mg/L, effluent T-N concentrations were very high with 80-120 mg/L and average
T-N removal efficiencies were low of 38% and 67% due to co-existing
phenomenon of nitrification and anammox processes. During the next periods,
influent T-N concentrations were increased from 300 to 400 mg/L and T-N
effluent concentrations were from 70 to 120 mg/L. The average T-N removal
efficiencies were higher of 72% and 74% than previous time owing to anammox
process has dominated in comparisons with nitrification process.
Therefore, the average T-N removal efficiencies for 4 reactors using PVA, MC
and PE sponge as biomass carriers were about of 73 to 80%.
3.2 T-N removal rates for 4 reactors using PVA, MC and PE sponge asbiomass carriers
PVA

MC (d=3-5mm)

MC (d=10-15mm)

PE sponge

3

T-N RR (kg/m /d)Changes in T-N removal
3.5
rates for 4 reactors using
3
PVA, MC and PE sponge
2.5
as biomass carriers areshown in Fig. 4.
2
For PVA reactor, T-N
1.5
removal rates increased
from 0.27 to 1.35 kg
1
N/m3/day during 244 days
0.5
of operation in phase 1. The
0highest T-N removal rate of
050
100 150 200 250 300 350 400 450 500 550 600
33.0 kg N/m /day was
Time (days)
obtained after long time
Figure 4: Changes in T-N removal rates
more than 550 days.
for different reactors
For MC1 and MC2 reactors,
T-N removal rates of MC1 reactor were around 0.5 – 0.6 kg N/m3/day duringinitial 186 days of operation and T-N removal rates of MC2 reactor were around
0.5 – 0.7 kg N/m3/day during a shorter time of operation of 145 days. Then, T-N
removal rates of MC1 reactor were increased stepwise from 0.6 to 3.1 kg
N/m3/day in the next 129 days of operation. The T-N removal rates of MC2
Comparisons nitrogen removal capacities by anammox process using different biomass
Comparisonscarriers
nitrogen removal capacities by anammox process using different biomass carriers961

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamreactor show the similar results of MC1 reactor and increased stepwise from 0.7 to
3.1 kg N/m3/day in the next 85 days of operation. The high T-N removal rates
obtained showed that the anammox bacteria grew actively in the anammox
reactors using MC as biomass carrier.
For PE sponge reactor, T-N removal rates increased quickly from 0.1 to 0.6 kg
N/m3/day. T-N removal rates of 2 kg N/m3/day was obtained after 5 months ofoperation. This PE sponge reactor is continuing in operation to obtain higher T-N
removal rates.
The T-N removal rates for MC1 and MC2 reactors obtained similar results of 3.1
kg N/m3/day over shorter time of 315 days and 230 days, respectively, incomparisons with the T-N removal rate for PVA reactor of 3 kg N/m3/day overlonger time of 564 days. In addition, T-N removal rate of 2 kg N/m3/day was
obtained in short operational time of 140 days for PE sponge reactor, incomparisons with the T-N removal rate of 2 kg N/m3/day for PVA reactor, MC1
and MC2 reactors over longer time of 546 days, 265 days and 185 days,
respectively owing to the largest porous diameter of PE sponge material. PVA
reactor was operated with longer time due to the mechanic problems. On the other
hand, operation of MC1 and MC2 reactors and PE sponge reactor are simpler andeasier than operation of PVA – fluidized-bed reactor. However, the fluidized-bed
reactor could reduce substrate inhibitions by complete mixing using a high recycle
flow rate. This substrate inhibition will be the big problem for the operation of the
fixed-bed reactors.
3.3 Ratios of T-N removal, NO2-N removal and NO3-N production rates to
NH4-N removal rates for 4 reactors using PVA, MC and PE sponge asbiomass carriers
Ratios of T-N removal, NO2-N removal and NO3-N production rates to NH4-N
removal rates for 4 reactors using PVA, MC and PE sponge as biomass carriers
are shown in Table 6. These values were similar to the stoichiometry value of the
anammox reaction. The ratios of PVA reactor over phase 2, MC2 reactor and PE
sponge reactor over phase 4 were closer to the theoretical ratios in comparisonswith the ratios of PVA reactor over phase 1, MC1 reactor and PE sponge reactor
over phase 3. Consequently, the anammox activities in PVA reactor over phase 2,
MC2 reactor and PE sponge reactor over phase 4 were considered better than
PVA reactor over phase 1, MC1 reactor and PE sponge reactor over phase 3.
Table 6: Reaction ratios of NO2-N removal, NO3-N production and T-N removal
rates to NH4-N removal rates for 4 reactors using PVA, MC and PE sponge asbiomass carriers
Reactors
Period ofNO2-N/ NO3-N/ T-N/
the operational time
NH4-N NH4-N NH4-N
Theoretical ratios
1.32
0.26
2.06
PVA reactor
Phase 1 (days 120-364)
1.12
0.22
1.91
Phase 2 (days 365-617)
1.18
0.21
1.96
MC1 Reactor
368 days
1.15
0.17
1.98
MC2 Reactor
280 days
1.2
0.17
2.03
PE sponge reactor
Phase 3 (days 90-111)
1.19
0.3
1.88
Phase 4 (days 112-141)
1.23
0.24
1.99

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3.4 Possible applications
With above experimental results, anammox process using PVA, MC and PE
sponge materials as biomass carriers in the FBR and the fixed-bed reactors will besuitable for NH4-N removal from wastewater containing high NH4-N such as
livestock farms, sites of aquaculture and agriculture, food and brewery processing
industries, landfill leachate, etc. However, these wastewaters always contain highconcentration of organic matter. Therefore, it is necessary to make clear whether
PVA, MC and PE sponge materials can tolerate high organic carbon
concentrations in anammox process.
4 CONCLUSIONSWith same operational conditions such as temperature, influent pH, influent DO,
T-N removal efficiencies for 4 reactors using PVA, MC and PE sponge asbiomass carriers were about of 73-80%. Influent T-N concentrations should be not
too high (not higher than 550-600 mg/L for PVA reactor, and not higher than 500550 mg/L for MC1 and MC2 reactors under too short HRTs (less than 3 h).
Conversely, when T-N concentrations are higher than 550-600 mg/L for PVA
reactor and 500-550 mg/L for MC1 and MC2 reactors, HRTs should be increased
to more than 3 h. PE sponge reactor is operating to realize which level of T-N
concentrations will be properly under short HRT. The T-N removal rates for MC1
and MC2 reactors obtained similar results of 3.1 kg N/m3/day over shorter
operational time of 315 days and 230 days, respectively, in comparisons with the
T-N removal rate for PVA reactor of 3 kg N/m3/day was obtained after long
operational time of 564 days. In addition, T-N removal rate of 2 kg N/m3/day was
obtained after short operational time of 140 days for PE sponge reactor, incomparisons with the T-N removal rate of 2 kg N/m3/day for PVA reactor, MC1
and MC2 reactors over longer operational time of 546 days, 265 days and 185
days, respectively owing to the largest porous diameter of PE sponge material.
PVA reactor was operated with longer time due to the mechanic problems.
Furthermore, operation of MC1 and MC2 reactors and PE sponge reactor are
simpler and easier than operation of PVA – FBR. However, the FBR could reduce
substrate inhibitions by complete mixing using a high recycle flow rate.
Anammox process using PVA, MC and PE sponge materials as biomass carriersin the FBR and the fixed-bed reactors will be suitable for NH4-N removal fromwastewater containing high NH4-N. However, it is necessary to investigate
whether PVA, MC and PE sponge materials can operate under high organiccarbon concentrations in anammox process, because these wastewaters always
contain high concentration of organic matter.
REFERENCES
APHA, AWWA, WEF, 1995: Standard methods for the examination of water andwastewater. 19th edition, American Public Health Association, Washington, D.C.
Christian Fux, Marc Boehler, Philipp Huber, Irene Brunner and Hansruedi
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Comparisonscarriers
nitrogen removal capacities by anammox process using different biomass carriers963

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Vietnam0ctober
VietnamSiegrist, 2002. Biological treatment of ammonium-rich wastewater by partial
nitritation and subsequent anaerobic ammonium oxidation (anammox) in a pilot
plant. Journal of Biotechnology 99, 295-306.
Furukawa K., Rouse J.D., Imajo U., Nakamura K. and Ishida H., 2002. Anaerobic
oxidation of ammonium confirmed in continuous flow treatment using a novel
nonwoven biomass carrier. Jpn. J. Wat. Treat. Biol. 38, 87-94.
Furukawa K., Rouse J.D., Yoshida N. and Hatanaka H., 2003. Mass cultivation ofanaerobic ammonium-oxidizing sludge using a novel nonwoven biomass carrier. J.
Chem. Eng. Jpn. 36, 1163-1169.
Jetten M. S. M., Strous M., Van de Pas-Schoonen K. T., Schalk J., Van Dongen
U.G.J.M., Van de Graaf A. A., Logemann S., Muyzer G., Van Loosdrecht M.
C.M., Kuenen J. G., 1999. The anaerobic oxidation of ammonium. FEMS
Microbiol Rev.22, 421-37.
Kanda J., 1995. Determination of ammonium in seawater based on the indophenol
reaction with O-phenylphenol (OPP). Water Research 29, 2746-2750.
Mulder A., Graaf A. A. van de, Robertson L. A and Kuenen J. G., 1995.
Anaerobic ammonium oxidation discovered in a denitrifying fluidized bed reactor.
FEMS Microbiol. Ecol. 16, 177-184.
Rouse J.D., Fujii T., Sugino H., Tran H., and Furukawa K., 2005. PVA-gel beads
as a biomass carrier for anaerobic oxidation of ammonium in a packed-bed reactor,
CD-ROM. Proceedings of 5th International Exhibition and Conference on
Environmental Technology. Heleco ’05.
Rouse. J.D., Yoshida N., Hatanaka H., Imajo U. and Furukawa K., 2003.
Continuous treatment studies of anaerobic oxidation of ammonium using a
nonwoven biomass carrier. Jpn. J. Wat. Treat. Biol. 39, 33-41.
Strous, M., Fuerst, J.A., Kramer, E.H.M., Logemann, S. M., Muyzer, G., van dePas-Schoonen, K.T., Webb, R., Kuenen, J.G., and Jetten, M.S.M., 1999. Missing
lithotroph identified as new planctomycete. Nature 400, 446-449.
Strous, M., Heijinen, J.J., Knenen, J.G., and Jetten, M. S. M., 1998. The
sequencing batch reactor as a powerful tool for the study of slowly growing
anaerobic ammonium-oxidizing microorganisms. Appl. Microbiol. Biotechnol. 50,
589 - 596.
Strous, M., Kuenen, J.G. and Jetten, M.S.M., 1999. Key physiology of anaerobic
ammonium oxidation. Appl. Environ. Microbiol. 65, 3248-3250.
Strous M, Van Gerven E, Kuenen JG, Jetten M. S. M., 1997. Effects of aerobic
and micro-aerobic conditions on anaerobic ammonium oxidizing (anammox)
sludge. Appl Enviro. Microbiol. 63, 2446 – 8.
Strous M., Van Gerven E., Zheng P., Gijs Kuenen J. and Jetten M. S. M., 1997.
Ammonium removal from concentrated waste streams with the anaerobic
ammonium oxidation (Anammox) process in different reactor configurations.
Water Research 31, 1955-1962.
Van de Graaf A. A., De Bruijn P., Robertson L. A., Jetten M. S. M., Kuenen J. G.,
1996. Autotrophic growth of anaerobic ammonium-oxidizing micro-organisms ina fluidized bed reactor. Microbiology 142, 2187-2196.
Van de Graaf A.A., Mulder A., De Bruijn P., Jetten M.S.M., Robertson L.A. andKuenen J.G., 1995. Anaerobic oxidation of ammonium is a biologically mediatedprocess. Appl. Environ. Micorobiol. 61, 1246–1251.

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Investigation of residential water end-use
in urban areas of Hanoi
Huyen T.T. DANG1 and Nga T.V. TRAN1
1
Water Supply and Sanitation Department,
Institute of Environmental Science and Engineering,
University of Civil Engineering, Vietnam.
Email: huyendangctn@gmail.com

ABSTRACT
Most of water supply master plans and water investment projects in Hanoi andother cities have used national water demand criteria that was built based on
experience and reference from elsewhere. The purpose of this research wastherefore to investigate the real water consumption in Hanoi megacity andinitially focus on residential areas. In this study, the micro-component data fromhousehold related to different water activities such as toilet flushing, kitchen,laundry, bathing and others including vehicle washing, gardening, etc., werecollected via in-person interview and flow measurement. Results from nearly 180
household survey within two months (July and August 2013) in nine (09) Hanoi
central districts showed the average consumption was 24.8 L/p/d for toilet, 15.17
L/p/d for laundry, 52.86 L/p/d for bathroom, 36.5 L/p/d for kitchen and 5.13 L/p/dfor other water uses (house cleaning, fish pool, vehicle washing and gardening).
The total daily water use of urban residence was averagely 134 L/cap/day. This
number was much lower than the current criteria of 165 - 200 L/cap/day formegacities. The study would be a formal evidence for revision of national
technical standard on urban water demand in near future.
Keywords: Water consumption, end-users, survey, national criteria revision,urban areas
1. INTRODUCTION
Estimation of water demand is very important step in water supply development
projects. This requires understanding of water demand criteria for that area. At
macro view, selection of appropriate water demand is crucial for optimization ofwater service infrastructure planning.
Studies of residential water end use (RWEU) began as early as 1990s in USA andAustralia where the water saving was crucial due to severe droughts in thesecountries (Mayer, 1999; Roberts, 2005). In Australia, they even published aresidential end-use measurement guidebook to guide how to design, sample andselect proper technology (Giurco, 2008). Over 20 years, there have been
thousands of studies worldwide to address the current and future water demand in965

October
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Vietnamtheir countries such as China, New Zealands, United Kingdom, Canada, Israel, etc.
Looking into the basic water demand worldwide, it is shown that this value varies
country by country (Human Development report, 2006). This report clearly
showed the dependence of water use on economic condition, i.e., water
consumption decreased from European countries and USA (100-600 L/cap/day) to
Asian countries (100 - 200 L/cap/day) and then African countries (less than 100
L/cap/day). The water demand also varies city by city, for example, average dailywater use in Australia ranges from as little as 100 litres per person in some coastal
areas to more than 800 litres per person in the dry inland areas. Many factors
affect residential water demand. Both empirical investigations and analyticalstudies of industrialized countries suggest such determinants as policy variables(i.e. water price or water rate) household economic variables (income); physicalfeatures and technological variables (i.e. water amenities and metering, or watersaving plumbing fixtures); environmental variables (i.e. temperature andprecipitation); and demographic variables (i.e. household size and attitudinalvariables) (Zhang and Brown, 2005). Figure 1 depicts clearly the dependence ofwater use on economic condition, i.e., water consumption decreased from
European countries and USA to Asian countries and then African countries.
In Vietnam, determination of residential water demand for designing water supply
systems is mostly based on the National technical criteria TCXDVN 33:2006.
These criteria were referred from international and national designing experience,but not based on real data. According to TCXDVN 33:2006 criteria, the water
demand varies depending on types of cities (megacities, big cities, medium or
small cities, etc), urban or peri-urban.
Table 1. Residential water demand criteria
Type of city
Subjects
Water demand
Water demand
Criteria for 2010 Criteria for 2020
(L/cap/day)(L/cap/day)
Urban
165
200
Megacities,
Peri-urban
120150
category I cities,
resorts, tourism
places
Urban
120
150
Category II cities
Peri urban
80
100
and category III
cities60
100
Category IV cities
and category V
cities and ruralareas

Note: Megacities or Special cities: >5mi. cap; Category I cities: >1mil. cap (central cities) or> 500 thousand cap. (provincial cities); Category II cities: >800 thousand cap (central cities)or > 300 thousand cap. (provincial cities); Category III cities: >150 thousand cap.; Category
IV cities: >50 thousand cap.; Category V cities:>4 thousand cap. (Source: Vietnam
Urbanization Review, 2011).

There have been not many studies on residential water demand in Vietnam. The
first one was done in 2006 by Japan Society for the Promotion of Science and966

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there was another study in 2010 by Japan Science and Technology (JST).
According to the first survey of 21 urban households (HHs) and 17 peri-urban
HHs in 2006, the water consumptions were reported as high as 170 L/cap/d and
92 L/cap/d for urban and peri-urban Hanoi respectively (Busser et al, 2006).
While results from 2-month survey at 200 households in peri-urban Hanoi showedthat the average consumption was about 70 L/cap/day (Otaki et al., 2012). It is
worth noting that Hanoi is classified as Special city. Given the time of study, thecurrent Vietnam criteria for urban Hanoi are sort of close, but the criteria for periurban is too high compared with the research results. It can be seen that the firststudy was conducted with very limited number of HHs and did not cover all
districts of Hanoi. For better understanding of residential end-use water
consumption, it encourages to have another study at bigger scale to somehow
confirm the result. Besides, little is known about which determinants (water price,water amenities, climate or people awareness, etc) affect Hanoians the most inwater use.
The objective of this paper was therefore to (1) investigate the end-use water
consumption in urban Hanoi at a larger scale; (2) understand better how water isused by end users (i.e. for bathing, cooking, toilet or washing, etc.); (3) comparewith the current criteria to see if it is relevant, and finally (4) demonstrate therelationship of water use and social and economic determinants.
2. METHODOLOGY
The study focuses on the behaviors of households that affect their water use andconsumption. "Residential water consumption", in the context of this survey,
refers to the water from both household faucets that are used for toilet flushing,cooking, bathing, laundry and similar purposes, such as flower watering or car
washing (Zhang and Brown, 2005). The survey also elicited the consumer’s
opinions on present water supply in order to understand quality of the service
delivered.
2.1. Sample size
It is clearly that the more number of samples, the more accuracy and confidence
the result can achieve. However, the choice of how many sample is often acompromise between the cost and the required level of statistical significance. In
this study, a total targeted random sample of 173 households was selected inurban Hanoi.
2.2. Sample selection
Initially the sample selection aimed to base on income or household style asreferred to some previous studies (Roberts, 2005; Zhang and Brown, 2005).
According to Roberts's study, higher income households are often responsible fora higher proportion of peak demand use. In other speaking, the actions of high use
households are more important than those of low use households, thus, theydecided to deliberately sample 50% of high use households, 25% of low use
households and the rest for middle use ones. In Zhang and Brown study, theInvestigation of residential water end-use in urban areas of Hanoi
Investigation of residential water end-use in urban areas of Hanoi

967

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Vietnam0ctober
Vietnamstratified random sample was selected based on the proportions of housing types(high rise, low rise buildings, or individual houses) in Beijing that they estimated.
However, official statistics of housing types or income are not available in Hanoi.
One understandable reason is that Hanoi is still in transition process with changes
year by year. Only the population density statistic is known. Therefore the numberof households was selected depending on population density. As the focus for thisstudy is urban Hanoi area, the samples were randomly selected from 9 central
districts: Ba Dinh, Hai Ba Trung, Hoan Kiem, Dong Da, Cau Giay, Thanh Xuan,
Hoang Mai, Long Bien and Tay Ho districts (Table 2).
Table 2. Sample selection
Districts
Population density*
Number of(persons/km2)
surveyed HHs
24,50223
Ba Dinh
27,85120
Hoan Kiem
5,443
12
Tay Ho3,7585Long Bien
18,74119
Cau Giay
37,16023
Dong Da
30,80524
Hai Ba Trung
8,175
21
Hoang mai
24,555
26
Thanh Xuan
173
Total
*Source: http://vi.wikipedia.org/wiki/To chuc hanh chinh tai ha noi, 2009)
2.3. Survey method
The survey involved household visits 173 houses during July and August 2013,
identified appliances by inspection, measured appliance flowrates and gathered
extensive data on usage behavior (i.e., water bill). Individual household was asked
to provide information by answering 33 questions covering four aspects: (1)household housing condition; (2) household socio data (age, gender, occupancy);(3) household water amenities and facilities; and (4) household water use behavior
and perception.
3. RESULTS AND DISCUSSION
3.1. Characteristics of households and survey areas
Number of persons/household (HH)
The majority (57%) of surveyed houses have less than 5 members in a HH. This
reflects the typical modern family in Vietnam in general and Hanoi in particular.
HHs (>10 persons) with three generations or with multi families is not so common
now in Hanoi.

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Figure 1: Number of person/household (X)Types of houses

Figure 2: Surveyed housing typologies
The multi-story house refers to single house (or un-detached townhouse withcourtyard or without courtyard) with 2 - 5 stories. One story house is the most
simple and oldest house structure. This type of house is not common nowadays insuch a megacity as Hanoi. They often are re-constructed to accommodate more
people or become house-for-rent. Low-rise building refers to old residential
blocks constructed between 1960 - 1980 in Hanoi. They often have max 5 stories,
each story has 5-10 flats. High rise buildings refers to recently-built residential
blocks which were built within the last 15 years, mostly developed in Hoang Mai
and Cau Giay districts. Each building has more than 10 stories and number of flats
varies depending on the size of building. Villas account for only about 2% ofsurveyed HHs. This type of house is also not very common since the land areas
required large, at least 200 m2/HH.

Investigation of residential water end-use in urban areas of Hanoi
Investigation of residential water end-use in urban areas of Hanoi

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October
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VietnamMulti-story houses

High rise buildings

Low rise buildings

One story (single story) houses
VillasFigure 3: Images of Hanoi housing typologies
It is interesting that the randomly selected HHs for survey seems to reflect theobserved housing typology distribution in Hanoi. In which, multi-story houses aremost common types of houses in Hanoi (78%), followed by newly-built high-risebuilding flats (10%), and then low-rise building flats (9%). Villas and is not so
popular and one-story houses are not our target in this survey.
3.2. Average water consumption
Figure 4 presents the average water consumption in 9 districts. The average wateruse varied from 120 L/cap/day to 143 L/cap/day. It is worth noting that most ofLong Bien district was used to be sub-urban area, therefore, the living standard is
not so as high as the urban districts, so does the water consumption.
On the other hands, as many rich people moves to Cau Giay or Hoang Mai to live

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in new residential areas, the houses are bigger and more modern. Water amenities
are also more fancy and so does the water consumption. In Tay Ho district, thewater consumption is relatively high since people here use well water (which is
free of charge) quite often as the second water source.

Figure 4. Average water consumption per person per day in 9 districts
The average water use was found about 134 L/person/day. This was lower than
the figure of 170 L/person/day discovered by the Japanese research group in 2006.
Compared to Vietnam water consumption criteria for Special city like Hanoi of
165-200 L/cap/day for period of 2010-2020 (TCXDVN 33:2006) and the designed
value in Water Supply Masterplan for Hanoi toward 2020 of 160-180 L/cap/day,this result was also lower than that range. This source of data would be a base andreal evidence for water supply system design and management in Vietnam.

Figure 5. Average residential water consumption distribution (q: water
consumption - L/cap/day)
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Look into the breakdown of water consumption, the amount of water use forbathroom accounts for the most and quite significant, followed by those forkitchen and for toilet. This pattern is quite similar with those found in previous
studies in other cities but at different absolute values (Prathapar et al., 2005;
Friedler 2004).

Figure 6. Breakdown of residential water consumption

Figure 7. Micro-component residential water consumption in Hanoi and Chiang
Mai (Otaki et al., 2012; Otaki et al., 2013)
Compared with Otaki's result (2013) which also has done in Hanoi, this study
shows a bit higher values. It is because they conducted survey mostly in periurban Hanoi while this study was done in urban Hanoi. Micro-component
residential water consumption in Hanoi and Chiang Mai seemed similar, except
for laundry use. While compared between peri-urban Hanoi and peri-urban
Chiang Mai, the difference was for bathroom use.
3.3. Impact factors on residential water consumption per capita per day
Type of house
The high-rise flats are more modern and larger than the low-rise flats which are

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smaller and were built 30-50 years ago. It was found that the water consumption
increases with following order: low-rise building flats (136 L/cap/d) < multi-story
houses (136.5 L/cap/day) < high-rise building flats (154 L/cap/day). Evidence canbe seen that the water used for house cleaning in multi-story houses or in high risebuilding flats would be than for low rise ones due to large living and cleaning
areas. Other explanation may lie in the living condition. High-rise buildings arethose recently built which attract many high-income residents. High-income
people often have higher living standard. Due to larger space, they use more water
amenities and/or more fancy ones. Therefore, their water use is significantly
higher.
Water availability (water quality, water sufficient or insufficient supply)
More than 80% of HHs reported no complains about water quality and quantities.
Nevertheless, water interruption for few hours can occur once every few months
due to power saving plan or construction. It would say if the water availability
were limited, the water consumption would be lower. The high water use fromthis study proves that water shortage is not a common issue in Hanoi city.
In house water leakage
Based on the survey, there was not much water leakage from water amenities
reported. Only a few cases were found, related to improper close of tap faucet,
leak of pump hose and leak from old toilet spray hose. Once a while there wasreported leakage event related to failure of water heaters due to hot water pipe
rusty.
In general, HH water leakage is also not a common issue. They often fix once
water amenity is leaked since it impacts directly their water bills.
Others (frequent guests, non-permanent residents)
Compared with the measured data and billed water use, there is about 15%
difference. This could be due to either subjective reasons such as inaccuracy
measurement of water amenities, and responders' insufficient information, or due
to objective reasons such as staying of non-permanent residents, use of anotherwater sources or water penetration from HH's underground water reservoirs. The
objective causes are usually hard to control. However that difference of 15% isunderstandable and within accepted range.
About 6% of surveyed HHs uses wells water. Therefore that fraction is notincluded in average billed water consumption. HHs using dual water sources
mostly located in Ho Tay (West lake) and Long Bien districts where the fresh
water supply is constrained and wells water level is highly available.
4. CONCLUSIONSHousehold survey in 9 districts of Hanoi was conducted to investigate theresidential water demand. Here are some of our key findings:- Households in urban Hanoi consumed much less water per capita thanpreviously found in 2006's study (134 L/cap/day compared with 170 L/cap/day). It
could be due to many reasons, however, some of them to be recognized are theincrease of awareness of water saving; application of water-saving devices (forInvestigation of residential water end-use in urban areas of Hanoi
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2013, 2013,
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Vietnam0ctober
Vietnamexamples two-button toilets in stead of one-button ones), impact of water price,
etc. This data was lower the current standard for residential water consumption
design of 165-200 L/cap/day.
- Water consumption increases with following order: low-rise building flats <multi-story houses < high-rise building flats. In addition, there was slightly
variation on water consumption among 9 districts. Long Bien district was used tobe sub-urban area, therefore, the living standard is not so as high as the urban
districts. In Tay Ho district, use of well water is quite common as second water
source.
- Household water use and consumption in Hanoi were predominantly indoor uses,
due to housing and climate conditions.
- Most families in Hanoi were satisfactory with their current municipal water
service and not concerned with the billing system- The amount of water use for bathroom accounts for the most and quite
significant, followed by those for kitchen and for toilet. This pattern is quite
similar with those found in previous studies.
- Many factors impact on water use among surveyed households. However, there
were no clear dominant determinants to explain the variation in household water
use.
REFERENCE
Barrett, Greg; Wallace, Margaret. 2009. Characteristics of Australianurban residential water users: implications for water demand management andwhole of thesystem water accounting
framework. Water
policy,Volume: 11 Issue: 4 Pages: 413-426
Busser S., Pham T.N., Antoine M., Nguyen V.A. 2006. Characteristics andquantities of domestic wastewater in urban and peri-urban households in Hanoi,
Annual Report of FY-The Core University Program between Japan Society for the
Promotion of Science (JSPS) and Vietnamese Academy of Science andTechnology (VAST), P.395-P.397
Friedler, E., 2004. Quality of individual domestic grey water streams and its
implication for onsite treatment and reuse possibilities. Environmental
Technology, 25(9): 997-1008
Giurco, D., Carrard, N., McFallan, S., Nalbantoglu, M., Inman, M., Thornton, N.
and White, S. 2008. Residential end-use measurement Guidebook: a guide to
study design, sampling and technology. Prepared by the Institute for Sustainable
Futures, UTS and CSIRO for the Smart Water Fund, Victoria.
Grafton R. Q., Ward M.B., To H., Kompas, T. 2011. Determinantsof residential water consumption: Evidence and analysis from a 10-country
household survey. Water resources research, Volume: 47
Zhang H. H., Brown D. F., 2005. Understanding urban residential water use in
Beijing and Tianjin, China. Habitat International, 29, 469–491.
Jacobs H. E. 2007. The first reported correlation between end-use estimates ofresidential water demand and measured use in South Africa. Water SA, 33-4, 549558

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Otaki Y., M. Otaki, P. N. Bao, T. T. V. Nga and T. Aramaki, 2013. Microcomponent survey of residential water consumption in Hanoi, Water Science &Technology: Water Supply, 13.2, 469-478.
Otaki Y., Otaki M., Ping L., 2012. The survey on the consumption of domestic
water use in Hanoi and its analytical results, Proceedings, The 2nd Climate
Change and Urban Water Systems-Workshop for Adaptation and Better
Management, Hanoi, Vietnam, March 5-7th, 2012.
Roberts P., 2005. Residential End Use Research to support Demand management
and forcasting, Vicwater Conference.
Mayer P. W., DeOreo W. B., Opitz E. M., Kiefer J. C., Davis W. Y., andDziegielewski B., Olaf Nelson J.,1999. Residential End uses of water, AWWA
Research foundation.
Prathapar S.A., Jamrah A., M., Ahmed S. Adawi Al, Sidairi S. Al, Harassi A. Al,
2005. Overcoming constraints in treated greywater reuse in Oman, Desalination
186, 177–186.
Sharon L. H., Scott T. Y., Larissa L., Anthony J. B. 2009. Household Water
Consumption in an Arid City: Affluence, Affordance, and Attitudes, Society &Natural Resources: An International Journal, Volume 22, Issue 8, pages 691-709
Vietnam Urbanization Review. 2011. Technical Assistance Report, World bank.

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New Technologies for Urban Safety of Mega Cities in Asia

Pollution and eutrophication control
in urban lakes

1

Ha D. TRAN1 and Huyen T.T. DANG2Assoc. Prof., PhD, Water Supply and Sanitation Division,
2
PhD, Water Supply and Sanitation Division,
Institute of Environmental Science and Engineering,
Hanoi University of Civil Engineering, Vietnam
E.mai: tranducha53@gmail.com; hatd@nuce.edu.vn

ABSTRACTIn Vietnam, urban lakes are often considered as an urban ecological framework
and play vital roles in municipal infrastructure system. However, many of them
are in danger of having high level of eutrophication due to the disposal of untreated wastewater and rainwater run-off. The lakes' water quality has degradedover the years because of algae explosion, organic re-pollution and unstabledissolved oxygen. Environmental experts from Hanoi University of Civil
Engineering have proposed a series of solutions during the implementation ofmunicipal drainage and sewerage and sanitation projects. Among them areseparation of wastewater from discharging into the lakes, oxygen enrichment,
aqua plant development, flow re-arrangement, etc. Those solutions have helped
improve water quality, reduce pollution and eutrophication in some lakes in
Hanoi, Haiphong, Danang and other megacities.
Keywords: Urban lakes, pollution control, eutrophication, control solutions,megacities.

1. INTRODUCTION
Vietnam currently has about 765 cities with different scales as of end of 2012
(Ministry of Construction, 2012). The urban residential areas and economic
centers of Vietnam are mostly located in large river deltas, coastal areas orwherever have great sources of surface water such as channels and lakes. The
flows through urban channels and lakes form ecological framework, creatingwater sources for domestic supply, manufacture and other urban activities. On theother hand, many urban cities are located in low land; therefore, the innerchannels or lakes play an important role in drainage, rainwater regulation andwastewater reception. The urban drainage system is often designed as in Figure 1.

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Wastewater drainage basin
Drainage and sewerage system
Regulated and stored lakes
Conveyance system
Discharge system
Figure 1. Diagram of urban drainage system
The density of drainage channels and lakes in Vietnam's urban cities is relatively
high, about 10-15% of total urban area. The inner lakes' areas are ranging fromseveral hectares to hundreds of hectares. They are divided into four functiongroups as below:- Group 1 including lakes used for tourism, water sport and rain water
regulation for the surrounding areas. The water quality of these lakes complies
with Type A- National technical criteria QCVN 08:2008/BTNMT, for instances,
West lake, Hoan Kiem Lake...in Hanoi city.
- Group 2 including lakes for water entertainment and rain water
regulation for surroundings. They can be also used for fish raising. The water
quality of these lakes complies with Type B- National technical criteria QCVN
08:2008/BTNMT, for instances, Goong lake in Vinh city, Tam Bac lake in Hai
phong city, Thien Quang lake and Bay Mau lake in Hanoi, etc.
- Group 3 including ones for relaxing, entertainment of residential areas;
regulating storm water for surroundings, and receiving treated wastewater. Theselakes are often used for fish raising such as Giang Vo lake in Hanoi, Binh Minhlake in Hai Duong province, etc. Again, the water quality should meet therequirement of National technical criteria QCVN 08:2008/BTNMT-Type B.
- Group 4 are storage and regulated lakes for big areas or many basins in
the city. They can receive treated wastewater, be used for fish and other aquatic
animals raising. They are often the largest receiving lakes in the city such as Yen
So lake (Hanoi), Au Thuyen lake (Hai Duong), Kenh Gia lake (Nam Dinh), etc.
The water quality should meet the requirement of National technical criteria
QCVN 08:2008/BTNMT-Type B.
Urban channels and lakes are often connected with each other through a united
system, creating an urban ecological framework. Lakes are usually connected intoa chain (system) such as Giang Vo lake-Ngoc Khanh lake-Thanh Cong lake-Dong
Da lake-To Lich river chain; Giam lake-Van Chuong lake-Trung Tu-Lu river in
Hanoi; An Bien lake - Mam Tom lake - Thien Nga lake - Dong Khe channel in

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Hai Phong; Hao Thanh lake- Binh Minh lake - Bach Dang lake - Ke Sat river in
Hai Duong, etc...to receive and regulate rainwater runoff and wastewater.
2. CURRENT POLLUTION AND EUTROPHICATION IN URBAN LAKES
Urbanization is the main factor causing water quality changes in urban lakes andrivers. In addition, the untreated wastewater disposal is the main reason thatmakes urban lakes more and more contaminated. Even though, under tropicalclimate condition, the ability of self-cleaning of these lakes is significant, thefrequent reception of untreated and overloaded wastewater makes it impossible
for self-cleanning process, resulting in severe pollution in urban lakes. The
evidence can be seen most clearly in Hanoi, Hai Phong, Da Nang, Hue, Nam Dinh,
Hai Duong and other large cities where the number of centralized wastewater
treatment plants have not met the demand.
The monitoring data of the urban lakes in the past few years has showed that someparameters such as BOD5, COD, NH4-N, Coliform, etc did not meet therequirement of national technical criteria QCVN 08:2008/BTNMT-type B. Figure
2 depicts the BOD fluctuation with years in West lake (floating restaurant) andBay Mau lake (in the middle of lake), Hanoi.

West lake
Bay Mau lake
Level B1 –QCVN08:2008

Level A2 – QCVN08:2008

Figure 2. BOD fluctuation in West lake and Bay Mau (Hanoi), monitored by
Institute of Environmental Science and Engineering (IESE) from 1994-2012
The channels and lakes which receiving untreated wastewater are all contaminatedwith 2-70 times higher than allowable values for all parameters. These lakes arecontaminated at α - β mezoxaprobe level. The sediment at the bottom of lakes
contains significant organic matters and heavy metals, which contributes to lake
pollution and flow constraint.
In municipal wastewater, the normal N:P ratio is 4:1, however in natural lakes, theconcentration of P is often much lower due to settling, transformation, digestion
by aqua plants, etc, thus the N:P ratio can be up to 21. Table 1 presents the
Pollution and Eutrophication control in urban lakes
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Vietnamrelation of N and P in a couple of urban lakes in the North of Vietnam, reported
by IESE, University of Civil Engineering in 2009 (Tran, 2009).
Table 1. N and P concentrations in urban lakes in the North of Vietnam.
No

Name of Lake

Depth H,
m

TN,
mg/L

TP,
mg/L

N:P ratio

1

Tinh Tam lake (Hue)

1.5

3.25

0.17

19.11

2

An Bien (Hai Phong)

2.9

3.19

0.15

21.2

3

Bay Mau lake (Hanoi)

3.0

5.19

0.24

21.6

4

West lake (Hanoi )

1.62

0.08

20.2

5

Goong lake (Vinh)

4.21

0.20

21.05

2.5

Usually, the N:P ratio depends on types of lakes, their depth, surface loading of P
and N, etc. According to Vollenweider (1980) and Downing (1992), when N:P
ratio was greater than 12, TP would be used as indicator of eutrophication. Due toreceiving significant amount of rainwater and wastewater with high P loading,almost urban lakes in Northern provinces are in danger of eutrophication (Tran,2009). The biological capability is often quite high (20-30g O2/m2-ngày), causing"blooming" in the lakes. This phenomenon leads to the reduction of surface
oxygen and increase of water turbidity. The relationship between Hanoi urban
lakes and eutrophication-causing factors is illustrated in below empiricalformulas:- Phospho and chlorophyll a relationship:
Log(Chl. a) = 0,69 log ( Cp) +2.58
Where:(1)

Chl.a –chlorophyill a concentration, ∓g/L;
CP- TP concentration in the lake, mg/L.

- Chlorophyll a and Secchi-disk transparency relationship:
S=6.4 (Chl.a)-0.473
Where:(2)

S - Secchi-disk transparency, m.

- Oxygen demand in lake bottom:
D=0.086 Cp0.478
Where:(3)

D- Oxygen demand in lake bottom, g of O/m2.d;
CP- TP concentration, ∓g/L.

- Relationship of orthophosphate and color:
C=15,6.e0.577P
Where:(4)

C- color, Pt-Co;
P- concentration of PO43-, mg/L.

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The above results proved that the relationship between chlorophyll a and P
concentrations was often presented in a logarit relation. The chlorophyll aconcentration greatly depended on P concentration and N:P ratio. This wasconsistent with findings in the studies of Dillon and Rigler (1974), Rast and Lee(1978). The linear relationship between P loading rate and other water parameters
were also the same as some previous studies (Vollenweider and Kerekes, 1980).
Together with eutrophication was the outbreak of such algeas as Cyanophyta,
Chlorococcales, Centiric Diatoms, Euglenophyta, etc. According Tran (2006), thetoxic algeas have invaded Hanoi lakes with concentration of 50-100mcg/L, andabout 2-3 mil of cells/L. They even reached 16-18 mil of Microcystis toxic algea
cells per L in some urban lakes such as Giang Vo, Thanh Cong, Thanh Nhan,
Hoan Kiem lakes, etc.
One of the challenges we are facing is the number and area of urban lakes as wellother surface water sources have been decreasing due to illegal occupancy,
leveling for housing development or waste dumping, etc. Based on IESE's survey
data, the urban surface water areas have been reduced from 10-50% in the past 10
years. The uneven and sometimes over-controlled precipitation has caused
overloaded infrastructure and led to pollution potentials. This mostly due to thefact that the management of urban lakes has not been focused and unified.
3. MITIGATION METHODS FOR EUTROPHICATION AND WATER
IMPROVEMENT IN URBAN LAKES
Tran (2010) has studied and summarised several methods for control andmitigation of eutrophication and pollution in urban lakes. This section will discussin details the four key solutions.
3.1. Reduction of untreated wastewater discharge into the lakes
Minimizing the disposal of wastewater into lakes is one of the best options toimprove the lake water quality. Since most of the current sewerage and drainage
systems in Hanoi and other cities are combined system, the best solution is toconstruct combined sewer overflows and interceptors around the lakes. By doing
this, the wastewater will not be discharged into lakes, but collected and delivered
to centralized wastewater treatment plants. This solution has been applying inWest lake and Truc Bach lake in Hanoi. The principle is illustrated in Figure 3.

Pollution and Eutrophication control in urban lakes
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October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 3. Diagram of controlling the wastewater and initial rainwater fromdischarging into the lakes
Note: (1) Combined sewer Overflows for wastewater and initial rainwater runoff;(2) Flap gate; (3) Wastewater treatment plant
3.2. Promotion of self-cleaning process
Self-cleaning process is a complex of natural processes including hydrodynamics,
biology, chemistry, physics, etc inside contaminated lakes in order to recover tooriginal status (components and characteristics). This means, the contaminants indischarged wastewater are further treated in the lakes.
Self-cleaning involves in two basic processes: dilution of wastewater and thereceiver and metabolism of contaminants with time. Thus, there are sometechniques that could be used to mitigate the "blooming" and reduce pollution as
follows:- Application of foutains, water turbins, water games (canoeing, pedalos,etc). The fountains can actually increase architure view and improve microclimate in the surroundings.
- Combination with water animals raising or Phytoplankton to increase
dissolved oxygen.
The above techniques can be enhanced by artificial aeration. The main principle isto provide more oxygen to microoganisms so that they can disgest organic mattersin the wastewater. The oxidation within the lake is mainly self-oxidation, however,
it is supported with a series of other reactions for lake water recovery. Currently,
there are many types of artificial aeration; among them are dynamics,
hydrodynamics, air blowing or other mixing, aerating processes.

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Figure 4. Application of overflow weirs and foutains for oxygen enrichment inurban lakes
In urban lakes, the bottom water is often oxygen poor and nutrient rich due tosettling and sedimentation disturbance. Thus, it is critical to supply of oxygen andreduction of nutrient to bottom water. To solve the problem, the most common
practice is to pump the bottom water to a wetland and the treated water with lower
organic and nutrient matters will be circulated to the lakes. Besides, it isrecommended to use flora and fauna system to remove contaminants based on themetabolism via food chains. In water, algea and aquatic plants absorb nutrients (N,P) and C to growth mass and create the basic capacity of water environment.
Aquarium plants play a vital role in subtracting organic matters, nutrients andheavy metals (Tran V. Quang, 2010). It is the lake water characteristics that
decide types of aquarium plants used. This is a high effective, cheap, easy-toconduct solution. On the other hand, it improves the attraction of urban lakes,
which are usually a good place for entertainment.

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October
2013, 2013,
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Vietnam0ctober
VietnamFigure 5. Aquarium plants (left) and constructed wetland (right) for self-cleaning process
in urban lakes
3.3. Enhancement of lake management
In order to apply appropriately methods for urban lake management, it isnecessary to classify them based on their function. This would help determine
authority responsibility levels and avoid complexity in management, which are
happening in many local areas in Vietnam. For instance, the main function of
inner lakes is to regulate rainwater runoff and flooding control, while for thoselocating at the beginning of drainage basin with limited capacity of regulation,
they should be used mainly for entertainment.
The strategy of lake management can be outlined as followings:- Close management of land use in lake surroundings;- Preparation of detailed regulations on management and reclamation ofwater;- Development of rehabilitation projects for existing urban lakes;- Establishment of environmental control system around the lakes;- Establishment of punishment procedures for lake violation activity.
3.4. Improvement of people's awareness on water resource protection
Besides the above technical methods for reducing eutrophication in urban lakes,
it is vital to socialize the management and water protection activities to change
the people behaviors and make people think of doing it as their responsibility,
duties and benefits.
The basic concept of socialization is to build hygiene living habits and avoid
pollution-causing manufactures. In addition, people should be educated so thatthey understand the importance of lakes and rivers in their lives, as a result
make them involved in environmental protection in general and urban lakes
protection in particular.

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CONCLUSIONS

Urban lakes really play vital roles in urban activities. Nevertheless, manyof them are in danger of pollution and eutrophication. So as to ensure theirfunctions in rainwater regulation and environmental landscaping, it isnecessary to apply integrated solutions including employing appropriatetechnologies and enhancing community education.

REFERENCE
Dillon, P. J., and F. H. Rigler. 1974. The phosphorus-chlorophyll relationship inlakes. Limnol. Oceanogr. 19: 767-773.
Downing JA, McCauley E. 1992. The nitrogen:phosphorus relationship in lakes.
Limnol. Oceanogr.37: 936-945
Rast, W. and Lee, G. F. 1978. Summary analysis of the North American (USportion) OECD eutrophication project: nutrient loading-lake response
relationships and trophic state indices, USEPA, EPA-600j3-78-008. Corvallis
Experimental Research Laboratory, Corvallis, Oregon.
Tran D. H., 2009. Protection and Management of Water resources Book, Scienceand Technique Publisher.
Tran D. H., 2010. Complex solutions for urban lakes improvement, Institute ofEnvironmental Science and Engineering, University of Civil Engineering.
Tran D.H., 2006. Evaluation of water quality fluctuation of five rehabilitated lakes
and proposal of treatment solutions, Hanoi Science research report ( Mã số: 01C09/06-2005-1).
Tran V. Quang. 2010. Rehabilitation of urban lakes by eco techniques.
Proceedings, 2nd International Conference on Environment and Resources,
Hochiminh city, 2-3/11/2010.
Vollenweider, R.A. and Kerekes J.J. 1980. Background and summary results of
the OECD cooperative program on eutrophication. Proceedings of theInternational Symposium on Inland Waters and Lake Restoration. U.S.
Environmental Protection Agency. EPA 440/5-81-010, pages 25-36.

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New Technologies for Urban Safety of Mega Cities in Asia

Introducing speed humps as acountermeasure for enhancing traffic safetyin urban residential areas: Some insightsfrom experiments in JapanDo Duy DINH1, Aya KOJIMA2and Hisashi KUBOTA3
1
Lecturer, Department of Highway and Traffic Engineering,
National University of Civil Engineering, Vietnam
doduydinh@yahoo.com
2
Assistant Professor, Graduate School of Science and Engineering,
Saitama University, Japan
3
Professor, Graduate School of Science and Engineering,
Saitama University, Japan
ABSTRACTDuring the last decade, Japan has experienced an increasing trend in thepercentage of accidents occurring on residential areas over all road accidents.
This fact suggests that dealing with traffic safety issues on neighborhood streets is
a promising area for enhancing the safety of urban cities in general. While
excessive vehicle speed is the main traffic safety concern of the local streets,
speed humps have been known as an effective tool to solve this speeding problem.
Despite the safety benefits, speed humps have not been commonly used in Asian
countries unlike North American and European counterparts. Meanwhile, a very
limited experience in using the device from Asian areas has been reported. This
paper, therefore, is to present some preliminary results of several humpexperiments in Japan. A sinusoidal mobile hump (FLEXITEC) was developed anddeployed on a number of residential streets. The results proved that the developed
humps can effectively reduce vehicle speeds and generate an acceptable level ofnoise and vibration. The effectiveness of speed humps ranged at different intervals
was also evaluated based on the viewpoint of noise and vibration as well as theeffect of speed reduction. While the safety effects of setting humps on local streets
have been proven elsewhere, the present paper provides helpful knowledge forpractitioners on introducing humps as a safety countermeasure for traffic safetyissues in Asian cities. .
Keywords: traffic safety; traffic calming; speed humps; residential street.
1. INTRODUCTION
During the last decade, Japan has been sustaining a decreasing trend in thenumber of traffic fatalities. According Traffic Bureau, National Police Agency,
the total number of deaths by traffic accidents dropped by nearly a half from 8326
fatalities in the year 2002 to 4612 fatalities in 2011. With respect to the road type,987

October
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Hanoi,Hanoi,
Vietnam0ctober
Vietnamthe percentages of accidents occurred on residential roads with road width of 5.5m or less amongst all accidents increased to 25.7% in the year 2007 and the figure
has been almost no change until now. This fact suggests that dealing with traffic
safety issues on neighborhood streets in Japan is a promising area for enhancing
the overall traffic safety as well as the safety of urban cities in general.
A number of studies have been proven the strong relationship between vehicle
speeds and road crashes. Meanwhile excessive vehicle speed is often deemed as
the main traffic safety concern of the local areas. In Japan, a lot of efforts havebeen made to reduce neighborhood traffic problems. Most residential streets areoperated at a speed limit of 30 km/h to favor for protecting vulnerable street users.
In addition, some engineering interventions such as speed signs, road marking,pavement coloring etc has been widely used. However, these measures seem to be
insufficient to solve the traffic safety issues in residential areas. As an illustration,
speeding is a serious problem on local streets and most people often exceed speed
limits while driving on these areas (Dinh and Kubota, 2013).
Speed humps have been known as traffic calming devices that can be used toeffectively reduce speeding problems. Previous research has documented thesafety benefits of traffic calming including speed hump installation. For example,
Zein et al. (1997) reported that traffic calming reduced collision frequency by
40%, vehicle insurance claims by 38%, and fatalities from one to zero. Despite
safety benefits, and while speed hump has been widely deployed in North
American and Europeans areas, the devices has been still very rare in many Asian
countries such as Japan.
It should be noted that speed hump may generate some side-effects such as noiseand vibration. It should be much considered in case of Japan where people areoften nervous about noise and vibration caused by this device. Even in countries
where speed humps are popular, the noise and vibration have become serious
issues (Harris et al., 1999; Lahrmann and Mathiasen, 1992). To obtain asustainable development of urban infrastructure, it is important to solve the sideeffect issues of speed hump installation. As a response to this, from 1990 several
researches to reduce noise and vibration of speed humps were conducted and thestudies found that the "sinusoidal" shape is the best from the viewpoint of noiseand vibration as well as passenger's comfort (Sayer et al., 1999).
Up to date there has been still very limited experience in using speed humps from
Asian areas. This paper, therefore, is to present some preliminary results ofseveral hump experiments in Japan under several research projects conducted by
the Urban Transportation Group of the Laboratory of Design and Planning,
Saitama University, Japan (i.e., Kojima et al., 2011; Dinh et al., 2013). In thisstudy, a sinusoidal mobile hump (FLEXITEC) was developed and experimentallydeployed on a number of residential streets. During the experiments, traffic
surveys were conducted to figure out the effects of humps on reducing vehicle
speeds. Social surveys regarding many facets of the hump installation were also
administered to residents who are living on the affected areas in order to find out
public opinions on the matter.

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2. HUMP DEVELOPMENTS
In 2000, the Urban Transportation Group of the Laboratory of Design and
Planning, Saitama University, Japan have developed "sinusoidal mobile hump
named as FLEXITEC" by using rubber made by Nippon liner Co., Ltd under acooperation project with the company. A lot of experiments were made during thehump development process to figure out the best shape of hump, its size, and its
suitable materials considering speed-reducing effectiveness and possible sideeffects such as noise and vibration. Two final models of hump (FLEXITEC) wereselected as shown in Figure 1. FLEXITEC is a “mobile” hump because its
configuration consists of 1m square units that facilitates the installation process as
illustrated in Figure 2.

(4m-wide/4m-length/10cm-height)
Bow-shape(4m-wide/6m-length with 2mflat/10cm-height)
Flat-top

Figure 1: Sinusoidal mobile hump (FLEXITEC)

Figure 2: Preparation ofexperiment

Figure 3: Introducing hump in frontof non-signal intersection

The research group has proven that, FLEXITEC can effectively reduce vehicle
speeds while generating little side-effects. Regarding noise, FLEXITEC can evenreduce noise of the site because the noise produced by vehicle engine issignificantly lower due to the speed reduction while the hump itself makes little
noise due to its sinusoidal shape and rubber material. It has been also proven thatFLEXITEC installed in front of non-signal intersections (see Figure 3) can
Introducing
humps as a countermeasure
fortrafficenhancing
Introducing speed
humpsspeed
as a countermeasurefor enhancing
safetytraffic safety in urban
residential
areas:
Some
insights
fromexperiments
inJapan
in urban residential areas: Some insights from experiments in Japan989

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamdramatically reduce traffic accidents possibly by waking drivers to adapt their
speeds.
3. SINGLE SPEED HUMP EXPERIMENTS
This section reported the effects of hump on reducing vehicle speeds when there
is only one hump installed on a relatively long street section. The target is to findout drivers’ speed choice behavior on the sections right before and right after the
hump-setting zone.
3.1 Experimental settings
For this studying purpose, two street sections were selected, both located on urban
areas of Minami-Hatogaya, Kawaguchi city, Japan. These sections are one-way
traffic with a speed limit of 30 km/h. On the traffic moving direction, these
sections are adjacent to a river embankment with limited accesses on the righthand side and residential neighborhoods on the left.
Excessive speeds are very serious on the streets that may cause unsafe forresidents nearby. To reduce vehicle speeds, two humps were installed on thesestreets, one hump for each street section. Figure 4 shows the sketch of the study
street sections and the location of humps.

Figure 4: Sketch of selected street sections for single-hump experiments
Speed profiles were recorded for individual vehicles by using STALKER ATS
radar guns connected to a laptop on the field. Vehicle speeds were measured both
before and during the humps experiment. At least 75 speed profiles were recorded
for each situation.
3.2 Results of single-hump experiments
Figure 5 presents the speed profiles for each street section while several speed
indicators are shown on Table 1.

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Table 1: Descriptive statistics of speed indicators

Indicators
Section 1
Maximum speed
within subsection 1
Maximum speed
within subsection 2
Speed at humplocation
Section 2
Maximum speed
within subsection 1
Maximum speed
within subsection 2
Speed at humplocation

Beforeexperiment
V85th

Mean
Mean
speed
speed
reduction reduction
Vmean V85th(km/h)
(%)

44.63

50.33

42.60

47.07

2.03

4.56

47.55

53.32

45.04

51.23

2.50

5.26

37.80

43.17

23.60

36.08

14.20

37.58

49.65

55.83

42.93

47.59

6.72

13.54

50.15

58.04

46.03

52.74

4.12

8.21

49.07

55.29

19.47

26.55

29.59

60.32

Vmean

Duringexperiment

Figure 5: Speed profiles before and during hump experiments
Introducing
humps as a countermeasure
fortrafficenhancing
Introducing speed
humpsspeed
as a countermeasurefor enhancing
safetytraffic safety in urban
residential
areas:
Some
insights
fromexperiments
inJapan
in urban residential areas: Some insights from experiments in Japan

991

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2013, 2013,
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Vietnam

The data showed that all mean speeds measured under the experiment are
significantly lower than those measured before the experiment at the 95% level.
Mean speeds at hump locations dropped rapidly after hump installation from 37.8
km/h to 23.6 km/h for Section 1 and from 49.07 km/h to 19.4 for Section 2.
However, a part of drivers still exceeded 30 km/h when passing the humps. Mean
speeds within the subsections before hump locations had a reduction of 2.03 km/h
(4.56%) and 6.72 km/h (13.54%) for Section 1 and Section 2 respectively. The
impact on mean speeds of the subsections after humps location seems to besmaller with only a decrease of 2.5 km/h (5.26%) for Section 1 and 4.12 km/h
(8.21%) for Section 2 under the experiment. On average, drivers need a distanceof about 30 m to decelerate from a speed of 40 km/h to the speeds at the humplocation. Also, the acceleration rate after passing the hump is very high with only
a necessary acceleration distance of less than 20 m to reach the speed of 30 km/h
for Section 2.
The findings suggest that if the remaining length of the subsections before andafter hump locations is large (more than 150 m as those under the current study),
necessary measures should be considered to ensure the targeted speed reduction.
Attention should be also paid at the high deceleration/acceleration rate occurred
before/after hump location.
4. MULTIPLE SPEED HUMPS RANGED AT DIFFERENT INTERVALS
As illustrated in Section 3, a single hump is often insufficient to make drivers tokeep lower speeds than the speed limit (i.e., a speed limit of 30 km/h applied formost residential streets in Japan) over the road section especially in cases thesection length is relatively long. For such cases, it is necessary to install a series ofhumps with appropriate intervals. This section aims at finding the appropriate
interval of ranged speed humps from the viewpoint of noise and vibration as wellas the effect of speed reduction through the field experiments.
To find out the appropriate interval between humps, driving speeds were
investigated on a study street with humps ranged at four different intervals
including: 30m, 40 m, 60 m, and 100 m. The experiment was implemented along
the Kokubunji Koko Higashi Dori street running north-south in Kokubunji city,
Tokyo, Japan. It is a 3.6-meter wide and 600-meter long one way street: thedirection of the one-way regulation is southward. During peak hours, as many as
500 cars per hour use the street as an alternate route. Most of these cars run at
speeds over the legal limit of 20 km per hour. Thus, pedestrians and cyclists using
the street are exposed to the dangerous situation and the residents living along thestreet suffer from the noise and vibration brought about by through traffic.
In order to solve those traffic problems, speed humps were experimentally
installed on the street. The experimental period was for 4 weeks during Octoberand November in 2006. Four speed humps were successively placed and theintervals between the humps were changed every 1 week: 30m, 40m, 60m, and100m. The hump that was located at the north end was fixed throughout theexperiment and other three humps were moved.

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Before conducting the social experiment, there was a worry that drivers who do
not know about speed humps run through the humps at high speeds and make loudnoises. To avoid such situation, two kinds of humps, trapezoidal and sine curved
humps, were used. Trapezoidal humps have comparably less impacts on motor
vehicle occupants and make less noise than sine curved humps. One trapezoidal
hump was put on the north end and three sine curbed humps were placed next to
the trapezoidal hump. It was intended that drivers who experienced speed humps
for the first time could learn the role of humps by the trapezoidal hump at first.
We conducted traffic surveys during the experiment and resident attitude survey
after the experiment to evaluate ranged speed humps at four different intervals. In
the traffic surveys, we measured vehicle speed, noise, and vibration duringmorning peak hours. In the attitude survey, we investigated how residents like thehumps and how they thought about noise and vibration during the experiment.
The following subsections describe the results of the surveys.
4.1 Results of Traffic Surveys
4.1.1 Vehicle speeds
As mentioned above, in the four-week experiment, the intervals of four humps
were changed every week. We measured traffic speed at each interval, and before
and after the experiment with the target of 150 vehicles for each situation. Targets
were vehicles that traveling at free flow speed: it means that we choose vehicles
not in congestions and not being influenced by other cars, cyclists, and pedestrians.
Figure 6 shows block speed of vehicles from the trapezoidal hump located at thenorth end to the next hump. It displays the average, 85 percentile, the maximum,
and the minimum speed for each interval, and before and after experiment. Before
and after the experiment, the average vehicle speed is around 40km/h. All theaverage speeds measured in
the experiment period are
significantly slower than the
average speed measured
after the experiment at the
95% level. It suggests thatthe installation of ranged
humps is effective at all thefour intervals. However, thegraph also indicates that the
speed down effect decreases
as the intervals become
Figure 6: Speeds at different intervals
longer.
4.1.2 Noise
We measured noise produced by passing vehicles. The observation points are
installation positions of humps and middle points of each hump. Figure 7 shows
average momentary value of noise measured when cars run through eachobservation points. Comparing the average value of the subject street, 72.7dB, thenoise at the locations of humps and middle points of each hump is lower. At the
Introducing
humps as a countermeasure
fortrafficenhancing
Introducing speed
humpsspeed
as a countermeasurefor enhancing
safetytraffic safety in urban
residential
areas:
Some
insights
fromexperiments
inJapan
in urban residential areas: Some insights from experiments in Japan993

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnammiddle points, comparably high value of noise was observed than at the
installation points of humps.
Reacceleration of vehicles
after passing humps may
influence the result. There isno significant difference innoise values depending on
the interval of ranged humps.
4.1.3 VibrationWe
observedvibration
generated by cars at thesame points where noise was
Figure 7: Average momentary value of noise atmeasured. Figure 8 displays
different intervals
average momentary value ofvibration measured when cars run through each observation points. Contrary tonoise, the value of vibration is higher at the middle points of each hump than at
the locations of humps. The value of vibration observed at the midway between
humps is higher than the average value on the subject road measured after theexperiment. However, thevalue of vibration does notexceed the environmental
limit in Japan. So it isthought that the vibration
generated
duringtheexperiment period does not
influence the neighborhood.
There is no significant
differenceinvibration
values depending on theinterval of ranged humps as Figure 8: Average momentary value of vibrationin the case of noise.
at different intervals
4.2 Results of Attitude Survey to Residents
As aforementioned, an attitude survey was conducted to understand residents’attitude toward hump installation. The survey method used a questionnaire, andthe targets were heads of the households in the affected areas. The questionnaire
was distributed by having it dropped into each mailbox by laboratory students,
and it was collected by mail using a postage free envelope. After the time limit of
the collection, a follow-up survey was conducted for the heads of households who
did not reply. Out of 353 questionnaires administered, 179 questionnaires return
accounted for 50.7%.
The data showed that, in general residents living in the neighborhood seem tosupport the hump installation. 73.0 % respondents in the questionnaire survey
believed that the number of vehicles that slow down short of the humps“increased” or “somewhat increased”. Regarding the traffic safety effects, thepercentages of people who thought that the safety of the road was “improved” or“somewhat improved” are 50.0% and 56.5% for the stand point of pedestrian and994

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car driver respectively. As to safety for cyclist, the figure is 37.5%. The rate forcyclist is comparably lower than the former two modes possibly because cyclists
may have thought that the installation of humps make the part of roadway for
cycling is narrower. Furthermore, for the question “How do you like installinghumps on the road?”, 64.6% of respondents answered “good” or “somewhat
good” while only less than 20% had a negative response.
The side-effects of hump installation may be largest to the residents who areliving along the subject road where humps were placed. Taking account this, ananalysis was conducted based on the sample including only people whose house isalong the road. The sample size for this analysis is 18.
The data indicates that people living along the road recognized the slow down
effect of hump because up to 88.9% believed that the number of vehicle slowing
down their driving speeds “increased” or “somewhat increased”. However, on theother hand, the number of residents who thought noise and vibration became big
during the experiment is large among the residents living along the road: 44.4% ofthem answered the noise increased during the experiment, and 50.0% of themanswered that the vibration increased during the experiment. The noise andvibration concerns may be a possible reason for the negative evaluation to hump
installation regarding the group of people living along the road. Only 27.8% of the
respondents answered “good” or “somewhat good” to the question “How do you
like installing humps on the road?”. The value is significantly lower than that of
the whole respondents. This result and the former results indicate that although
the residents living along the subject road highly evaluate the ability of humps tomake the road safe, they are anxious about noise and vibration problems and had anegative impression of the installation of the humps.
4.3 Summary of the Experiment and Challenges
It is a big contradiction that residents along the road where humps were installed
complained about problem of noise whereas observed noise level is low enough.
Judging from free comments in questionnaire survey, the cause seems "reacceleration" after passing the humps. By analyzing the result of this experiment,
we have formulated a hypothesis about the reason of "re-acceleration" thatintervals of humps are too long and they promote drivers to re-accelerate as aresult.
5. EFFECTIVENESS OF HUMPS RANGED AT 20 M
Based on the lessons from the experiment in Kokubunji city, another experiment
was conducted in 2009. This time, the intervals of the humps are purposely set at
about 20m. It is expected that the 20m interval keeps drivers not to reaccelerate
their vehicles. The experiment was implemented in Bunkyo-ward in Tokyo, Japan.
The subject road is the ward road No.839, which is 4.5m width, 300m long oneway road. On the road, four humps were placed considering the road conditions
that resulted in three intervals as 19m, 24m, and 29m.

Introducing
humps as a countermeasure
fortrafficenhancing
Introducing speed
humpsspeed
as a countermeasurefor enhancing
safetytraffic safety in urban
residential
areas:
Some
insights
fromexperiments
inJapan
in urban residential areas: Some insights from experiments in Japan995

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamA speed survey was conducted both before and during the experiment. The results
provided in Table 2 showed that vehicle speeds decreased significantly after hump
installation.
Table 2: Speeds of vehicles before and during experiment
Speed indicators(km/h)
Average
Maximum
85% percentile

Before experiment(N = 99)2240
30

During experiment(N = 126)14
27
19

Noise was also measured
with the results provided in
Figure 9. As can be seen in
the figure, the level of noise
were restrained in the whole
section where the humps
were placed because the 20m
intervals prevented vehicles
from terrible reacceleration
after passing hump locations.
Figure 9: Momentary value of noise
Similar to the experiment in
Kokubunji city, a questionnaire survey was again conducted to residents living in
the affected areas. Regarding the noise issues, only 11.9% of respondents claimed
that the noise made them “annoyed” or “somewhat annoyed”. As for the question
with regards to whether humps should be permanently installed on the street,
59.4% of the people living along the subject street answered “agree”, “agree withreservations”, or “accept”. The results suggest that humps ranged at 20m intervals
did not have too big noise problems and the most residents accept the impact.
6. CONCLUSIONSThis study has made an attempt to investigate some technical issues regarding
setting humps on urban residential streets. Through the number of experiments, it
was found that the developed sinusoidal humps can effectively reduce vehicle
speeds while generate little noise and vibration when cars pass over.
In case there is only a single hump installed on a relatively long street section,although the mean speeds can reduce significantly to around 20 km/h at the humplocations, drivers often re-accelerate quickly afterward. The acceleration rate after
passing the hump is very high with only a necessary acceleration distance of lessthan 20 m to reach the speed of 30 km/h. Drivers also sharply decelerate their
speeds before reaching the hump location. On average, drivers need a distance ofabout 30 m to reduce from a speed of 40 km/h to the speed at the hump location.

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This paper also aimed at finding appropriate interval between humps when aseries of humps are installed on a street section. The appropriate interval was
judged from the view point of noise and vibration as well as the effect of speed
reduction through experimental installations. Regarding the interval, it was foundthat 60m-inerval can reduce speed to a speed of less than 30km/h in all over theroad section. The first experiment conducted in Kokubunji city, Tokyo seemed
successful judging from observed data. However, residents along the experimentstreet complained noise problems in any cases of experiment. Cause of the noise
was not the shock of traffic passing through humps but the re-acceleration of cars
after passing humps. In the second experiment conducted in Bunkyo-ward, Tokyo,
the intervals between humps were reduced to 20m to make drivers to "give up" reaccelerating. Judging from the result of the questionnaire survey and noise
observation, 20m-interval could control re-acceleration to the extent that residents
along the road are acceptable.
Although the present research has made efforts on understanding drivers’ speed
choice behaviors on hump-installed streets in Japan and some related issues, there
is still a lot of works that should be done before humps can effectively introduce
widely to urban cities for traffic safety preventions. For example, further studies
should focus on the safety effects of humps as well as the cost-benefit of the hump
installations.
REFERENCES
Dinh, D.D., and Kubota, H., 2013. Profile-Speed Data-Based Models to Estimate
Operating Speeds for Urban Residential Streets with a 30 km/h Speed Limit.
IATSS Research 36, 115-122.
Dinh, D.D., Kojima, A., and Kubota, H., 2013. Reducing Vehicle Speed on
Residential Streets: A Single-Hump Experiment. Paper for JSCE 15th
International Summer Symposium, Japan Society of Civil Engineers, Chiba,
September 2013.
Harris, J.I., Stait, R.E., Abbott, P.G., and Watts, G.R., 1999. Traffic calming:
Vehicle generated noise and ground-borne vibration alongside Sinusoidal, RoundTop and Flat-top Road Humps, TRL Report 416.
Kojima, A., Kubota, H., Yoshida, M., Ichihara, S., and Yoshida, S:, 2011.
Effectiveness of speed humps ranged at different intervals considering roadsideenvironment including vehicle speed, noise and vibration, Journal of the Eastern
Asia Society for Transportation Studies, 9, 1913-1924.
Lahrmann, H., and Mathiasen, P., 1992. Bumpudformning (Hump Design), Dansk
Vejtidsskrift Nr9, 16-22.
Sayer, I.A., Nicholls, D.A., and Layfield, R.E., 1999. Traffic calming: Passenger
and rider discomfort at Sinusoidal, Round-top and Flat-top humps a track trial at
TRL, TRL Report 417.
Traffic Bureau, National Traffic Agency. Traffic Accident Statistics. (in Japanese).
Zein, S., Geddes, E., Hemsing, S., and Johnson, M., 1997. Safety Benefits ofTraffic Calming, Transportation Research Record 1578, National ResearchCouncil, Washington, D.C., 3-10.

Introducing
humps as a countermeasure
fortrafficenhancing
Introducing speed
humpsspeed
as a countermeasurefor enhancing
safetytraffic safety in urban
residential
areas:
Some
insights
fromexperiments
inJapan
in urban residential areas: Some insights from experiments in Japan997

October 2013, Hanoi, Vietnam

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Some research on air qualityof Ulaanbaatar City (Mongolia) in wintertime
O.Enkh-Uyanga1, P.Chimedtseren2 , G.Solongo3
1Department of Chemistry , Ulaanbaatar school, National University of Mongolia
2- Disaster research institute under the NEMA
3Pulmonary department of 3th policlinic Ulaanbaatar
ouyanga2001@yahoo.co.uk

ABSTRACT
Ulaanbaatar, the capital city of Mongolia is subject to high air
particulate matter pollution episodes during winter. The process of urbanization
which had accelerated in Mongolia in mid 1990-s of the capital contributed to therapid growth of the capital which population is 1.1 million people while the totalof the country is 2.8million (2011) [1]
The air pollution is visibly worse in the wintertime. Some sources of air pollution
in Ulaanbaatar are four thermal power plants, about 200 small and medium sizedheating boilers, 168000 traditional gers (traditional nomadic dwelling), wooden
houses and 130000 automobiles. In these areas, the only source of heating are
fueled by coal and wood. Annual average burned consumption of coal is
5.9million ton and wood is 237,2 thousand ton in Ulaanbaatar.[2]We shown that , annual average particulate matter concentrations PM10, SO2,
CO2 comparative indices by last 5 year.
Research background: Pollutant substances including alien elements with dust,
mistiness, toxic gas derived from burning, especially sulfuric gas derived fromcoal burning, nitric acid, carbon monoxide, carbonic acid, ammonia, ozone, hydrosulfur, formaldehyde, heavy metals, mercury, lead, arsenic and cadmium are
regularly released from manufacturing, human activities and vehicles in the air inexternal surrounding of civilized areas.
In recent years, above chemical substance acetone amount in the air is a lot higher
than the norm due to high amount of smoke in our capital city. Therefore, thepopulation of the city often suffers from respiratory and cardiovascular illnesses
and cancer due to the consequence of air pollution. We have conducted thisresearch and defined content of pollutant substances including sulfuric anhydride,
nitric acid, dust, carbonic acid in the air on the basis of air quality report of
Ulaanbaatar between 2007 and 2012.

999

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2013, 2013,
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Vietnam0ctober
VietnamGraph 1. Air pollution factors in Ulaanbaatar
Research result: As the result of comparative study for air quality of 4 indicatorsof the statistical year based on air quality report of 2007-2012, amount ofchemical substances having adverse impact on respiratory and other organs andsystems is 1.5 to 5 times than the norm.
table.1
Amount of SO2 in the air content
Year
2007
2008
2009
2010
2011
2012
11
15
18
27
31
30
Content(mkg/m3) SO2
10
10
10
10
10
10
Content SO2of air quality
standard
As seen from the above table 1, SO2 amount in the air is 2.5 to 3 times higher thanallowed amount of 10 mkg/m3. Amount of SO2 in the air content of 2011 and2012 is 30mkg/m3 which is a lot higher than that of previous year’s averageamount.
As seen from the above table 2, amount of NO2 in the air is 0.2 to 0.6 times higher
than allowed amount in air quality standard of 40-50mkg/m3. Amount of NO2 in
the air content of 2011 and 2012 is a lot higher than that of previous year’s
average amount.
Amount of NO2 in the air content, Ulaanbaatar
table.2
Year
2007
2008
2009
2010
2011
2012
37
31
28
35
43
44
Content(mkg/m3) NO2
40
40
40
40
40
40
Content NO2of air quality
standard
Research result shows that NO2 amount in wintertime is 4 to 5 times higher thanallowed amount. Spring and autumn time amount is approximately 40-50mkg/m3
which is 1.5 to twice higher than the allowed amount. The result of measurement
conducted in most polluted areas of Ulaanbaatar shows that yearly average ofPM10 amount is 20 to 100 times higher than the international and Mongolian air
quality standard. Generally, dust substance amount in major cities is lower than
40mkg/m3. As seen from the above table 3, dust amount in the air of Ulaanbaatar

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is 3 to 5 times higher than the standard and there is a tendency to increase inrecent years.
Content PM10 in the air, Ulaanbaatar
table 3
Year
2010
2011
2012
Content PM10 of in
the air content
Content standard of
PM 10 in air quality

148

230

259

50

50

50

The above graph shows that smoke amount increasing in wintertime increases
yearly average dust amount in the air to the maximum. O3 amount in the air has
been determined in our country since 2011. The research result shows that ozone
amount does not reach allowed standard. For example, ozone amount in 2012 is 4
to 5 times lower than standard.
Conclusion:
1. Amount of SO2 in the air of Ulaanbaatar which has adverse impact torespiratory organs 2.5 to 3 times higher, amount of NO2 is 0.2 to 0.6 times
higher, dust or РМ10 amount is 3 to 5 times higher and ozone amount is 4
to 5 times lower than the allowed standard amount.
2. Amount of above chemical substance acetone in the air is high in winterand autumn. The lowest ozone amount is in winter.
3. The result of measurement conducted in most polluted areas of
Ulaanbaatar shows that yearly average of PM10 amount is 20 to 100 times
higher than the international and Mongolian air quality standard

Reference materials:
1. Сapacity Development project for
Ulaanbaatar city Mongolia. 2011
2. www.tsag-agaar.mn
3. http://www.therestorationresource.com

Air

pollution

Some researchon airqualityonofair
Ulaanbaatar
City (Mongolia)
wintertimein wintertime
Some
research
quality of Ulaanbaatar
City in(Mongolia)

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1002

New Technologies for Urban Safety of Mega Cities in Asia

Investigating future yield and adaptation
measures in rice production
under climate change scenarios
in Quang Nam province, Vietnam
Trang BUI THI THU1, Sangam SHRESTHA2
1
Lecturer, Hanoi University of Natural Resources and Environmental, Vietnam
1
Graduate Student, WEM, SET, Asian Institute of Technology (AIT), Thailand
thutrang.hunre@gmail.com
2
Assistant Professor, WEM, SET, Asian Institute of Technology (AIT), Thailand

ABSTRACTIn recent years, climate change has become a biggest problem in developing
countries all over the world, especially in Vietnam. Global climate change may
affect the yield of rice crop in the future. This study analyses the impacts ofclimate change on rice production and adaptation in Nui Thanh district, one
coastal district of central Vietnam where there are many natural disasters hit
annually. This study pursue to seek following queries including forecast future
rainfall, temperature and rice yield, and analyze adaptation measures to improverice production under different climate change scenarios in Nui Thanh district,
Quang Nam province, Vietnam. The study was based on firstly identification of
the problem in the study area followed by collection of secondary data collection
on weather, soil characteristics and crop management. Then the downscaling
model was used to predict the temperature and precipitation of the study area in
the future by A2 and B2 scenarios. The crop Aquacrop model was used tosimulate the yield response with the outputs of the SDSM. After that, the impact
of climate change scenarios on rice yield was analyzed. Lastly, the evaluation foradaptation measure to improve rice production under climate change based onwater management was determined.
Keywords: climate change, Aquacrop; investigating future yield; adaptation
measures; climate change scenarios; Nui Thanh district; Quang Nam province,
Vietnam.

1. INTRODUCTION
Vietnam has long seashore, large population and economic activities in coastalzone and heavy base on agriculture, forestry and natural resources (Tran Duc Vien,
2011). Agriculture plays an important role in economy of Vietnam nation,
especially in rural areas. As many developing countries, agriculture sector of
Vietnam largely depends on weather conditions. Precipitation plays an importantrole in supplication water source to crops directly. Annual average rainfall ofVietnam is more than 2,000mm in which monsoon rainfall occupies about 70% of1003

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total annual (Tran Duc Vien, 2011). At recent years, in the Central and Southern
Vietnam, the the frequency of flood has increased significantly, special in rainyseason. But most of other regions in country, the drought came due to decrease of
rainfall in dry season (Thuc, Tran, 2010). Rice has long been Vietnam's traditional
food crop and the country's export product. It is about 99.9 percent of Vietnam
population eats rice as their main meal. Paddy is grown on 53 percent of the
agricultural land in Vietnam, and it represents 64 percent of the sown area cropwith 60 percent of labor in rural area. Rice has recently become the second largest
export, accounting for 10 percent of total value. Vietnam had successfultransformed itself from a chronic rice importer to one of the three largest rice
exporters in the world. Nonetheless, climate change directly affected precipitationand temperature, with rise in temperatures leading to water deficit and foods in the
future, changing soil moisture status and pest and disease incidence (Chinvanno,2010).
Parry et al. (2004) analysed the global consequences to crop yields, production,and risk of hunger of linked socio-economic and climate scenarios. Potential
impacts of climate change are estimated for climate change scenarios developed
from the HadCM3 global climate model under the Intergovernmental Panel on
Climate Change Special Report on Emissions Scenarios (SRES) A1FI, A2, B1,
and B2. Projected changes in yield are calculated using transfer functions derived
from crop model simulations with observed climate data and projected climatechange scenarios. Tao and Zhang (2010) cited the highest benefits were obtained
from the development of new crop varieties that are temperature and have highthermal requirements. Based on simulations, at North China Plain (NCP) it was
found that for the high temperature sensitive varieties, early planting of the crop is
the effective option for reducing the yield loss from climate change in the region.
Also it was concluded that for high temperature tolerant varieties, late planting isa good adaption option moreover the spatial analysis shows the relative
contributions of adaptation options should be region and variety of crop specificas the adaptation varies geographically and crop variety.
Reidsma et al. (2010) analysed the adaptation of farmers and regions in Europe tothe prevailing climate change, climate variability and climatic conditions in thelast decade. The research concludes that, the impacts on the crop yields cannot betranslated to the impacts on the farmers’ income, since farmers adapt by changing
the crop rotations and inputs and the incomes are also dependent on the subsidies
by the government. Secondly, the observed impacts of climate change on thespatial variability on the yield and income is lower in warmer climates ascompared to temporal variability in climate in the places where there isheterogeneity in the crops grown. Thirdly climate change and variability impacts
are dependent on the farm characteristics (e.g. size, intensity and land use) whichhave ultimate influence on adaptation and management. As different farm types
adapts differently, hence a larger diversity in the farm types reduces the impactsof the climate variability at a regional level. Finally from the study, they
concluded that the yield and the farmers’ income in the future is mainly dependent
on the adaptation practices being followed which can reduce the potential impactsof climate change. Farmers continuously adapt to changes, which affects thecurrent situation as well as future impacts. Geerts (2010) used AquaCrop to derive1004

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deficit irrigation (DI) schedules. In this study, they use the AquaCrop model tosimulate crop development for long series of historical climate data. Subsequently
they carry out a frequency analysis on the simulated intermediate biomass levels
at the start of the critical growth stage, during which irrigation will be applied.
From the start of the critical growth stage onwards, they simulate dry weather
conditions and derive optimal frequencies (time interval of a fixed net application
depth) of irrigation to avoid drought stress during the sensitive growth stages andto guarantee maximum water productivity. By summarizing these results in easy
readable charts, they become appropriate for policy, extension and farmer leveluse. If applied to other crops and regions, the presented methodology can be anillustrative decision support tool for sustainable agriculture based on DI.
Climate change severe affects to the crops yield and finally to ramp up poverty in
Vietnam. Therefore, it is necessary to seek the solutions to adapt to climatechange, special for famer life and their agriculture production. The frame of thispaper focus finding out impacts of climate change on rice production in Nui
Thanh district of Quang Nam province in center of Viet Nam. The area often havetremendous catastrophically natural hazard by flood and typhoon. The main
objective of this research was to forecast future rainfall, temperature and rice yield,
and analyze adaptation measures to improve rice production under different
climate change. The specific objectives are: to forecast rainfall, temperature on
the future in the study area under climate change condition; to predict crop yieldin future under climate change scenarios; to evaluate adaptation measures toimprove rice production under climate change based on water management.

2. MATERIALS AND METHODS
2.1 Study area
The research was conducted in Nui Thanh district to typify for a coastal subregion in order to understanding the impacts of climate change on rice production.
Nui Thanh is the last district to the southward of the province and is adjacent to
Quang Ngai province. With diverse topography: coastal zone, plain zone andmountainous zone, Nui Thanh is hard hit by storm, drought in the coastal area,
flood in mountainous area, plain area. The hazards robbed the life and a lot of
property in this district in the past years. Nui Thanh is assessed as one of the mostserious damaged district by the hazard of Quang Nam province. Special, theimportant criteria for choice of study site are as follows: The high rate of
population cultivates agriculture as major livelihood; not only storm and food but
also the study site is affected by other irregular climate factors, such astemperature, rainfall.

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2.2 Climate data
The climate data were collected from Vietnam meteorological Department, with
the Tra My and Tam Ky stations (the weather stations nearest Nui Thanh), where
the experiments are performed. The data consists of daily weather data including
rainfall, maximum and minimum temperature (from year 1961 to 2000), averagemonthly weather data including rainfall, maximum temperature, minimum
temperature, sunshine hours, wind speed and relative humidity (from year 2000 to2010).
2.3 Future climate scenarios
The future climate scenarios was downloaded from the Global Climate Model
HadCM3 (Hadley Centre Coupled Model, version 3) developed by Met Office
Hadley Centre, England. (Website: http://www.cccsn.ec.gc.ca/?page=sdsm). The
high resolution data was developed considering the world growth forced by levelof atmospheric CO2 concentration according to IPCC SRES A2 scenario (which
is one of the most pessimistic projections) and B2 (another pessimistic projection
but population growth rate lower than A2). Then the data was downscaled to theregional level by using SDSM (Statistical Downscaling Model) for the study area.
The downscaled data for the period of 2014-2040, 2041-2070 and 2071- 2090 wasused for the grid which falls nearest to the study area.
2.4 Future climate scenarios
The data of rice crop was collected from Quang Nam Department of Agriculture
and Rural Development and Agriculture Division under Nui Thanh District
People's Committee as secondary sources. The data included major rice varieties,
transplanting date, density of plants, flowering date (anthesis date), senescencedate, maturity date, and method of sowing, irrigated schedule and the rice yields.
The information data is about two majors’ rice varieties grown in the Quang Nam
province: CH207 and TBR1 for period 2001-2010. The researcher assumed thatthe treatment and organic manures was provided full in the field. Other side, field

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surveys of smallholder farmers was conducted in three communes: Tam Hoa, Tam
Hiep and Tam Xuan II about one month. 30 smallholder farmers were randomly
selected from three communes and interview by trained assessors on a set ofquestions designed in a questionnaire. The questions were aimed to obtain
information on the: indigenous farming practices, variety preferences and attitude
to forwards modification of traditional farming method and crop varieties.
2.5 Soil properties data
The information about physical and chemical properties of the soil is collectedfrom Quang Nam state land and development section. The data required are soil
texture, pH, phosphorous, nitrogen, carbon and carbon exchange capacity.
2.6 Model
2.6.1 Downscaling of GCM data by SDSM
The general principle of downscaling is to relate large scale predictor variables to
sub-grid or station level climate variable. This study used the statistical
downscaling (SD) method to transfer large scale GCM grid data to local scalestation data which are required to feed hydrological models for the simulation of
future scenarios of climate change impact. The statistical downscaling model(SDSM) version 4.2.9 developed by Wilby et al. (2000) is use in this study. Thismodel used the principle of developing multiple linear regression transfer
functions between large-scale predictors and local climate variables (predictand)and these transfer functions were used for downscaling future climate predicted
by GCMs. This study used the period of 1961-1990 as the base period for model
calibration and validation. This period taken because most of the GCMs provide
their projected climatic data starting from 1961 and in most of the study region
observed climatic data are also available for this period. While using the modeledclimate results for scenario construction, the base line serves as reference period
from which the future changes are calculated. Downscaling with SDSM includes
of four main steps: screening of large scale climatic variables (predictors),
calibration of transfer functions, validation of downscaling model and scenario
generation generation.
2.6.2 ETo calculator
The weather data required by AquaCrop model are daily values of minimum andmaximum air temperature, reference crop evapotranspiration (ETo), rainfall andmean annual carbon dioxide concentration (CO2). ETo was estimated using ETo
calculator using the daily maximum and minimum temperature, wind speed at 2 mabove ground surface, solar radiation and mean relative humidity (RH). The
weather parameters were collected from automatic weather station located at a
distance of 13 m above sea level.
2.6.3 Calibration and Validation of Aquacrop model
Calibration or fine tuning of the AquaCrop model was run after preparing the
input data files consist of meteorological data, precipitation, evapotranspiration,
irrigation, plant and soil information from the field experiment during 2001 to2010 for two crop seasons. The model calibration was conducted by changing thefutureyield andmeasures
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data. The simulating value of model predicted the output the yield, biomass andcanopy cover (CC) which used to compare with measured yield and biomass ofthe experimental plot. The difference between the model predicted andexperimental data was minimized by using trial and error approach in which one
specific input variable was chosen as the reference variable at a time and adjusting
only those parameters that were known to influence the reference variable themost. The procedure is repeated to arrive at the closest match between the model
simulated and observed value of the experiment for each treatment combination.
In this study, the winter crop was performed based on rainfed. However, theirrigated experiments were performed on the summer crop. In some cases such as
upper and lower thresholds for canopy expansion, upper threshold for stomata
closure and canopy senescence stress the recommended default value by model
guidelines, was considered.

3. RESULTS AND DISCUSSION
3.1 Projection of future climate
3.1.1 Projection of future temperature
In this part, the SDSM was used to project the change in maximum and minimum
temperature in three periods: 2014-2040, 2041-2070 and 2071-2090 relative tobase period 1961-1990. The results show that the highest rise in maximum
temperature will be 3.69oC and the lowest rise will be 0.93oC by period 20142040 according to scenario A2. The scenario B2 indicates lower rate of rise withaverage value of 1.85oC relative to baseline period. The highest rise in minimum
temperature will be 1.72oC by period 2071-2090 and the lowest rise will be
0.35oC by period 2014-2040 according to scenario A2. The highest rise inminimum temperature will be 1.29oC by period 2071-2090 and the lowest rise
will be 0.39oC by period 2014-2040 according to scenario B2. The averagechange in maximum and minimum temperature for SRES A2 and B2 scenarios
are presented in figure 3.1.

Figure 3.1: The changing in the average annual of maximum and minimum
temperature

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The average of monthly maximum temperature and minimum temperature forthree future periods compared to baseline period with A2 and B2 scenarios are
showed in figure 3.2. The temperature presents considerably most similar trends
for two scenarios.

Figure 3.2: Monthly Tmax and Tmin average for 30 years interval for A2 and B2
3.1.2 Projection of future precipitation
In this part, the SDSM was used to project the precipitation in three periods:
2014-2040, 2041-2070 and 2071-2090 relative to base period 1961-1990. Figure
3.3 shows the relative changes in the precipitation for the study area projected forA2 and B2 scenarios for periods 2014-2040, 2041-2070 and 2071-2090 ascompare to baseline period of 1961-1990. Scenario A2 shows increase in averageannual precipitation by 0.66, 5.51 and 9.75% respectively for periods 2014-2040,
2041-2070 and 2071-2090. Scenario B2 has slightly higher increase rate on
periods 2014-2040 and 2071-2090, there are about of 1.83 and 5.62%. But it islower increase than scenario A2 in period 2041-2070, it is about 3.47 %.

Figure 3.3: The changing in the average annual of precipitation for A2 and B2
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The projected precipitation does not show any fixed trend for both scenarios.
There is wide variation at temporal and spatial scale throughout the basin. The
figure 3.4 shows the changing in monthly precipitation for the study area
projected for A2 and B2 scenarios for periods 2014-2040, 2041-2070 and 20712090 compared to baseline period of 1961-1990. Scenario A2 and scenario B2 aremost the same the trend. Those figures show decrease of precipitation during mostof rainy season and increase during dry season. The precipitation strong decreases
on January and April which is about 44.41 to 57.90%. The precipitation higher
increases on June, it is over 150%. But the total precipitation of June is not very
high; therefore the amount of changing is not too large. From the % changing in
there figures, it is impress that the impact of climate change is very serious on theend of XXI century.

Figure 3.4: Variation in change of precipitation for A2 and B2 scenarios
compared to the baseline period (1961-1990)
3.2 Forecast the yield in future period by using Aquacrop model
The rainy season in the northern delta usually begins in May-June and end on
October-November. In the central province, rainy season come later, the large
amount of rainfall usually during time of November-December. From the output
of SDSM for the future climate, the precipitation higher increases on June to
September, but the total rainfall during that time is not high, other case, the total
rainfall is high during the months from October to March, but the future
precipitation decrease on December, January, February, April and May. Therefore,
the researcher recognized that there would be difference trend impact to futureyield between the crop cycle Winter-Spring and Summer-Autumn. That why, thesimulation of yield have done for two crop seasons to discover the impact ofclimate change to the yield.
The figure 3.5 presents the percentage change in rice for A2 and B2 scenarios for
2014-2040, 2041-2040 and 2071-2090 relative to 2001-2010 simulated by
Aquacrop model during winter crop and summer crop.

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Figure 3.5: Percentage change in rice yields with A2 and B2 scenarios for periods
2014-2040, 2041-2040 and 2071-2090 relative to 1961-1990 during(a) Winter crop and (b) Summer crop
For winter crop, with rainfed when calibration Aquacrop model, all of future
periods the yield will reduce. The yield significantly decreases during period
2071-2090 with both A2 and B2 scenarios. The reason of forecasted yield
reduces significantly from the baseline period this may be due to the effect of the
reduced rainfall and the stress due to increased temperature during flowering.
Similarly the biomass also shows a reducing trend for both scenarios.The yield
simulated by Aquacrop express a decline 5.97 to 23.05 and 1.29 to 10.96 percent
compared to the yield of the baseline period for A2 and B2 scenarios respectively.
Therefore, for winter crop season, farmer should supplementary irrigation water
applied using furrow method for three times at 10 days interval starting, floweringand grain filling to reach the optimum yield in the future periods.
For the summer crop, with baseline period 2001-2010, the model calibrated for
irrigated crop. However, the rainfall significant increase on this season in the
future. Therefore, the water available will be enough for crop for some periods.
Then, the yield increase about 5% and 6.67 % for period 2014-2040, 2% and2.78 % for 2041-2070 with A2 and B2 scenarios respectively. The yield will
reduce 1.83% and 6.26% for 2071-2090 with A2 and B2 scenarios respectively.
During period 2001-2010, to obtain the high yield or do not lose yield rice, thefarmer had to supplement irrigation water. However, the output of SDSM for
future climate changes scenarios. The rainfall will increase starting from June
until September. This is the period of summer crop rice crop. Therefore, theadditional irrigation for rice in the forecast period is increased. So the model cancalibration for rainfed yield in the future period without additional water, which isperfectly consistent with the results predicted by SDSM model.
3.3 Agricultural adaptation measures
3.3.1 Impacts of supplementary irrigation on rice yield
Supplementary irrigation water applied using furrow method in incremental
amount of 20mmm, 40mm, 40mm, 80mm and 100mm. Each irrigation level wasapplied four times at 20 days interval starting, 20 days before flowering date tocoincide with the critical stages of rice growth, flowering and grain filling. The
figure below explains the percentage change in yield under supplementary 20, 40,
futureyield andmeasures
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irrigation are about 400mm in four applications and this would increase the yieldby 24.13% in 2014-2040, by 27.45% in 2041-2070 and by 42.1% in 2071-2090.
For the summer crop season, the optimum amount of supplementary irrigation isabout 320mm and this would increase the yield by 2.32% in 2014-2040, by 2.48%
in 2041-2070 and by 2.52% in 2071-2090. The application for irrigation water insummer crop does not increase the yields significantly because of this season has
fairly enough rainfall. The result shows there are good relative with the output of
SDSM model.

(a) rainfed(b) irrigation

Figure 3.6: Impact of supplemental irrigation on rice for A2 scenario(a) Winter crop (rainfed) and (b) Summer crop (irrigation)
The figure 3.7 below explains the percentage change in yield under supplementary
20, 40, 60, 80 and 100 mm for 4 applications as compared to rainfed crop (forwinter crop) and irrigated crop (for summer crop) under B2 scenario. The results
show that for all future periods, in winter crop, the optimum amount of
supplementary irrigation is about 400mm in four applications and this would
increase the yield by 20.13 % in 2014-2040, by 30.45 % in 2041-2070 and by
32.81% in 2071-2090. For the summer crop season, the optimum amount of
supplementary irrigation is about 320mm and this would increase the yield by
2.28 % in 2014-2040, by 2.35% in 2041-2070 and by 2.48% in 2071-2090. The
application for irrigation water in summer crop does not increase the yields
significantly because of this season has fairly enough rainfall. The result shows
there are good relative with the output of SDSM model.

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Figure 3.7: Impact of supplemental irrigation on rice for B2 scenario(a) Winter crop and (b) Summer crop
3.3.2 Impact of changing sowing date on rice yieldIn this section, the date for transplanting was changed with different dates todetermine which date is best to gain the optimum yield. The simulations were runwith the dates around one week, two week, three weeks… compared with thecurrent transplanting date. Figure 3.8 shows the percentage change in yield withdifferent transplanting dates for CH207 and TBR1 with A2 scenario. For wintercrop, the result shows that the transplanting date of 25th February is the optimum
for future period, which can increase the yield up to 18.14%, 19.87% and 20.43%
for 2014-2040, 2041-2070 and 2071-2090 respectively. Probably this due to thereason that, the precipitation is decreased during December to January, then if thetransplanting is during this time the yield would reduce. From the second week ofFebruary, the rainfall increase, it is better to transplanting from 10th -30th February.
For summer crop, the result shows that the transplanting date of 11st June is the
optimum for period 2014-2040 and 2041-2070, which can increase the yield up to
27.78% and 26.43% respectively. With period 2071-2090, the optimum is 18th
June, which can increase the yield up to 24.86%. Then, for summer crop, it isbetter to transplanting from 3rd – 18th of June.

Figure 3.8: Percentage change in yield with different dates for A2 scenario (Jan20th and Mar 19th are current planting date): (a) Winter crop and (b) Summer cropWith B2 scenario, for winter crop, the result shows that the transplanting date of
25th February is the optimum for future period, which can increase the yield up to
20.34%, 14.37% and 22.94% for 2014-2040, 2041-2070 and 2071-2090
respectively. Probably this due to the reason that, the precipitation is decreased
futureyield andmeasures
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period 2041-2070, the optimum is 3rd June, which can increase the yield up to
26.18%. Then, for summer crop, it is better to transplanting from 26th May to11th
June. Figure 3.9 shows the percentage change in yield with different transplanting
dates for CH207 and TBR1 with B2 scenario.

Figure 3.9: Percentage change in yield with different dates for B2 scenario (Jan20th and Mar 19th are current planting date): (a) Winter crop and (b) Summer crop

4. CONCLUSIONSIn this paper the impact of climate change on paddy irrigation required andvolumetric irrigation water demand have been presented. The results from thepresent study conclude that:
1. Downscaling with SDSM model has well estimated, then the simulated weather
data downscaled by SDSM from the GCM HadCM3 had a good agreement withobserved data. Therefore, the future scenarios weather data by HadCM3 canacceptable. Aquacrop model and the ETo calculator (Evapotranspiration fromreference surface) performed satisfactorily in the study.
2. The minimum temperature will increase about 0.350C, 1.100C and 1.720C inperiods 2014-2040, 2041-2070 and 2071-2090 respectively with A2 scenario; andincrease about 0.390C, 0.810C and 1.290C in periods 2014-2040, 2041-2070 and
1971-2090 respectively for B2 scenario to compare with the period minimum
temperature is 21.60C. In case of maximum temperature, for A2 scenario, the baseperiod temperature is 30.110C which will increase 0.930C (in period 2014-2040),
2.380C (in period 2041-2070) and 3.690C (in period 2071-2090) in the future; andfor B2 scenario, the maximum temperature increased 0.980C (in period 20142040), 1.790C (in period 2041-2070) and 2.780C (in period 2071-2090).
3. The annual precipitation may increase from 0.66% to 9.75% for A2 scenario
and from 1.83% to 5.62% for B2 scenario. The precipitation will be decreaseduring rainy season and increase from mid of dry season.

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4. When using Aquacrop for winter crop by rainfed calibrate. For all of future
period the yield will reduce. The yield significantly decreases during period 20712090 with both A2 and B2 scenarios. The yield simulated by Aquacrop express a
decline 5.97 to 23.05 and 1.29 to 10.96% compared to the yield of the baseline
period for A2 and B2 scenarios respectively. With summer crop, for baseline
period 2001-2010, the model calibrated for irrigated crop. However, the rainfall
significant increase on this season in the future. Therefore, the water available will
be enough for crop for some periods. Then, the yield increase about 5% and6.67% for period 2014-2040, 2% and 2.78% for 2041-2070 with A2 and B2
scenarios respectively. The yield will reduce 1.83% and 6.26% for 2071-2090
with A2 and B2 scenarios respectively.
5. For winter crop, optimum of supplementary irrigation is at 400mm which
would increase the yield about 24.13% to 42.1% with A2 scenario and about
20.13% to 32.81% with B2 scenario. The application for irrigation water insummer crop does not increase the yields significantly, the optimum amount of
supplementary irrigation is about 320mm and this would increase the yield by
2.32% to 2.52% with A2 scenario and 2.28% to 2.48% with B2 scenario.
6. Changing the transplanting dates can increase the yield to higher extent underclimate change scenarios. The yield obtains higher if transplanting during 10th-30th
February for winter crop, and from 26th May to 18th June for summer crop.

ACKNOWLEDGE
This work was supported by Information and communication technologies (ICTs)
project, The International Development Research Centre (IDRC), Ottawa, Canada.

REFERENCES
Chinvanno, S.,2010. Climate change adaptation as a development strategy:
Amajor challenge for Southest Asian Countries. Southeast Asia START Regional
Center, Chulalongkon University, Thailand.
Geerts, S., Raes, G., and Garcia, M., 2010. Using Aquacrop to derive deficit
irrigation schedules. Agricultural Water Management.
Parry, M. L., Rosenzweig, C., Iglesias, A., Livermore, M., Fischer, G., 2004.
Effects of climate change on global food production under SRES emissions andsocio-economic scenarios. Global Environmental Change 14 (2004) 53–67.
Reidsma, P., Ewert, F., Lansink, A. O., Leemans, R., 2010. Adaptation to climatechange and climate variability in European agriculture: The importance of farmlevel responses, European Journal of Agronomy, 32: 91-102.
Tao, F., Zhao, Z., 2010. Adaptation of maize production to climate change inNorth China Plain: Quantify the relative contributions of adaptation options.
European Journal of Agronomy, 33: 103-116.

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VietnamThuc, Tran., 2010. Impacts of climate change on water resources in the Huong
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Anaerobic submerged membrance bioreactor(AnMBR) for decentralized municipal
wastewater treatment in Vietnam conditions
T. T. V Nga*, Vu Duc Canh*, M. Kobayashi**, and S. Wakahara*** Institute of Environmental Science and Engineering, National University of
Civil Engineering, 55 Giai Phong Road, Hanoi, Vietnam** Water & Environmental Innovative Research Laboratory, Kubota Corporation.
Hama 1-chome, Amagasaki-City, Hyogo Prefecture, Japan. 661-8567.
Corresponding author: nga.tran.vn@gmail.com
ABSTRACTThe study aims to investigate the application of anaerobic processes coupled withmembrane filtration for the treatment of municipal wastewater at Vietnam
tropical climate conditions. A laboratory-scale anaerobic membrane bioreactors(AnMBR) was run treating domestic wastewater in Hanoi city. The reactor istreating wastewater collected on-site at a condominium with COD level of 300600mg/l, BOD: 180-350mg/l, NH4-N: 40-85 mg/L. The reactor has been operated
at different hydraulic retention times (48 hours, 36 hours, 24 hours and 12 hours)
for a period of about 335 days (from June 2012 to May 2013) at ambient room
temperatures ranging from 10-39°C. The removal of the total suspended solid,
the soluble chemical oxygen demand and the biochemical oxygen demand werevery good (100% for TSS, 78-95% for COD, and 80-88% for BOD). The AnMBR
system achieved less than 85 mg /l of COD and less than 30 mg/L BOD in theeffluent with organic loading rate from 0.28 - 2 kg COD/m3.day. The biomass
accumulated reached 10 - 12 g MLVSS/L in the last month of the operation period.
Biogas production with the rate continuously increased with the increase of theloading rate in AnMBR. The average content of the biogas in methane reached53-60% during the last month of operation period. Further, it is worthwhile
noting that although the researchers observed little difference in removal
efficiency for TSS, COD and BOD at the lower temperature, a significant
decrease in methane gas production was observed. The results imply physicalretention of organics by the MF membrane played a significant role in achieving
good and stable performance at wide range of temperatures. It suggests that
AnMBR could achieve the good and stable efficiency in the treatment of lower
strength wastewaters at temperatures below 15°C in winter time.
Keywords: Anaerobic membrane bioreactors, domestic wastewater, tropicalclimate, Ha Noi City.

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1. INTRODUCTION
Anaerobic treatments, which are commonly applied to highloaded wastewaters(sludge digestion and industrial wastewater treatment), have the following main
benefits compared to aerobic treatments: minimum sludge production due to thelow biomass yield of anaerobic organisms, low energy demand since no aerationis required, and biogas production that can be used to fulfil process energy
requirements (Ho and Sung, 2010). Most of high-rate anaerobic processes, such as
up-flow anaerobic sludge blanket (UASB), expanded granular sludge blanket(EGSB), and anaerobic filter are based on the attached growth systems. UASB
and EGSB have had wide applications in the treatment of industrial and municipal
wastewaters (Sutton et al., 2004).
Besides, over the last decade, the potential of the anaerobic processes as atreatment technology for low strength domestic wastewater has been evaluated.
Nevertheless, domestic wastewater is quite complex due to the presence of fatty
compounds, proteins, detergents, heavy metals and other toxic compounds. These
characteristics impose limitations to the anaerobic process in respect to COD
removal efficiency and also in terms of maximum organic and hydraulic loading
rates to be applied. However, maintaining a long sludge retention time (SRT) is
one of the challenges of anaerobic treatment processes due to the slow growth rateof anaerobic microorganisms. Therefore, the key to successful high-rate anaerobic
technology is to decouple hydraulic retention time (HRT) and SRT in order not
only to maintain high sludge concentration in the system but also to decrease
reactor size.
Membrane–coupled anaerobic bioreactors have been applied as one alternative tothe conventional anaerobic digestion process. A typical AnMBR system include: aanaeronic reactor which play a role as a digestor and memberbane modules which
can either submerge or place outside of the reactor. It can retain all of the biomassin the reactor more effectively without any fear of sludge washout irrespective ofshort HRT. In addition, AnMBR could produce superior effluent quality in termsof suspended solids, chemical oxygen demand (COD) and pathogen count, andthere is a possibility of reuse and recycling of the treated effluent for non-potablepurposes. Previous studies elucidated the potential of AnMBR for the treatment of
low strength wastewater at ambient temperature (Ho et al., 2007).
The objective of this project is to study the performance of an AMBR for thetreatment of low strength wastewater like municipal wastewater in Hanoi. The
focus was to transform the municipal wastewater into different valuable streams
such as biogas (energy). The second purpose of this work is to investigate theoptimum operation parameters while minimize backwashing or chemical cleaningof the membrane modules.

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2. METHODOLOGY
2.1. Laboratory experiment set up
A laboratory-scale anaerobic membrane bioreactors AnMBR with 5L ofworking volume were run ambient temperature. The anaerobic reactors were
equipped with biogas collection system and a blower for keeping the sludge in thesuspension and membrane scouring effect using gas generated from the system.
Other equipments are the transmembrane pressure sensor and a data logger, andlevel sensors to control permeate flow rate. The AnMBRs were coupled to a flat
sheet, polyvinylidene fluoride (PVDF) with nominal pore size of 0.4µm and total
filtration surface area of 0.09 m2 (supplied by KUBOTA Cooperation, Japan).
Feed water for the reactor was taken from the equalization tank placed at thebasements of Sky Tower condiminium (Address: 88 Lang Ha street). The raw
wastewater have evarage COD content of 250-570 mg/L; BOD 90-290 mg/L, TN: 25-170 mg/L, NH4-N: 22-152 mg/L. Seeding sludge (1.5 g/L) was obtained
from the mesophilic anaerobic digester in Yen So municipal wastewater treatment
plant. The AnMBR system hase been operated for more than 350 days at different
hydraulic retention times. The average hydraulic retention times for the entire
system were 48 hours, 36 hours, 25 hours and 12 hours. The membrane flux was
maintained at 0.03, 0.08, 0.12, and 0.24 m3/m2.day, respectively. The organic
loading rate was therefore 0.31, 0.54, 0.95, and 1.68 kgCOD/m3.day accordingly.
There was no sludge withdrawal except for the analysis and SMA test withfrequency of one time per week. No chemical cleaning was attempted during theentire experiment.
2.2. Sampling and Analysis
DO, pH, temperature of feed, feed and permeat (effluent) flowrate in aerobic
tank were measured daily by portable meters. Wastewaters and mixed liquor werealso sampled on times per week and analyzed for chemical oxygen demand(COD), Biological Oxygen Demand (BOD) total nitrogen (T-N), ammonia
nitrogen (NH4-N), dissolved oxygen (DO), Mixed Liquor Suspended Solid(MLSS) and Mixed Liquor Volatile Suspended Solid (MLVSS), Volatile fatty
acids (VFA). The concentrations of COD, T-N, NH4-N, MLSS and MLVSS wereanalysed following Standrd Method (APHA 2003) and HACH methods with theappropriate kits and a DR 2800 Spectrophotometer (HACH Company, USA). A
wet-test gas meter was used to measure biogas. Gas composition and methane gas
was analyzed using Test kit GAC25 (Japan). In addition, methanogenic activities
were measured in duplicate for suspended and attached using 250 ml serum
bottles containing acetic acids as a sole substrate.

Anaerobic submerged membrance bioreactor (AnMBR) for decentralized municipal
Anaerobicinsubmerged
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3. RESULTS AND DISCUSSION
3.1. AnMBR performance at ambient temperature
The reactor has been operated at different hydraulic retention times (48 hours, 36
hours, 24 hours and 12 hours) for a period of about 335 days (from June 2012 to
May 2013) at ambient room temperatures ranging from 10-39°C. Seeding sludge
was obtained from the anaerobic digester in Yen So municipal wastewater
treatment plant. Since it have been in operation for a couple of month, the MLSS
concentration of the sludge is still low, ranging from 1200-1500 mg/L. The resuls
show that the sludge concentration have been increased steadily when increasingof feed flow rate over experimental period and reached 10,000-12,000 mg/L at theend of the Phase 4 with the HRT is of 12 hours accordingly. It also indicates nosludge washout in the system.
Although pH in the AnMBR system was not controlled, the pH levels in thereactor did not affect anaerobic degradation of organics. VFAs profiles indicatesthat acetic acid was the predominant VFA in the reactor. Propionic and butyricacid were not detected.
3.2 Efficiency of the AnMBR in removing wastewater pollutants
Biological removal rate was calculated by the difference between influent COD
and mixed liquor COD divided by the influent COD, while physical removal rate
was the difference between the total COD removal rate and the biological removal
rate. The concentration of COD in feed and permeat, removal efficiency are
shown in Figure 1. COD in the feed water varied from less than 200 mg/L toabout 570 mg/L. With this range of COD values, the feed water could still bbe
classified as low strength wastewater. The removal rate for COD was stable andhigh after day 120 with COD in permeat is less thang 100 mg/L. Thenafter,
throughout the operation at different hydraulic retention times, the COD removal
rates remained stable.. BOD concentration in the permeat water is also stable andless than 30 mg/L, indicating AnMBR system effective in the treatment of organic
matter. The good removal efficiency for COD (78-95%) and BOD (80-88%)
could be achieved which meet the domiestic discharge standards into theenvironment (QCVN 14:2008 /MONRE, source type B).

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COD vào

COD raHi�u qu� x� lý
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%

Hi�u qu� x� lýN�ng đ� (mg/L)

1,000
900
800
700
600
500
400
300
200
100
0
0

50

100

150

200

250

300

350

Ngày

Figure 1. COD profiles in feed and permeat and removal efficiency in AnMBR
systemThe change in the ammonium concentratio in feed and permeat during operationis shown in Figure 2. Raw wastewater in the apartment building have highammonium concentrations, ranging from about 20 -152 mg/ L. Ammonium
concentration in permeat lso showed similar bands in anaerobic conditions, theammonium is the main nitrogen component and sustainable existence. It also
shows AnMBR system is ineffective in treating nitrogen counponds in
wastewater to achieve the curent discharge requirements, highlighing the the needof further processes to reduce its residual nitrogen levels to meet stringent
Vietnamese wastewater discharge standards
NH4-N vào

NH4-N ra300

N�ng đ� (mg/L)

250
200
150
100
50
0
0

50

100

150

200

250
Ngày

300

350

400

450

Figure 2. NH4- profiles in feed and permeat; and removal efficiency in AnMBR
system
3.2. Biogas volume
Biogas volume is collected and measured daily. Experimental results showed
the amount of gas significantly increased when hydraullic residence time in thesystem AnMBR reduced from 36 to 25 hours, hence the average organic loadincreased from 0:53 to about 1.6 kg COD/m3.day accordingly (Figure 3). The
methane ratio have been incereading and reached 60 -70% of the total amount of
biogas from day 180th , i.e when the system switches to 25 hour retention time.
Experimental results also show that average methane yield achieved 0.24 L
Anaerobic submerged membrance bioreactor (AnMBR) for decentralized municipal
Anaerobicinsubmerged
membrance bioreactor (AnMBR) for decentralized municipal. . .
wastewater treatment
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CH4/gCOD. This value is only about 60% compared with values calculated
theoretically at 20oC (0.34 LCH4/gCOD decomposed), showing a majority ofmethane is lost. The gas leakage control activities have been tightly controlled in
the system so the only reason could be possibly the gas dissolved in the waterand have been wash out of the reactor with permeat through the membrane. Thisobservation also coincides with findings from the previous studies (Ho and Sung,
2010). The loss of methane, especially when large-scale implementation, not only
to loss of biogas resources, but also bring negatively impact the greeenhousegases emissions. This issue should be further investigated to control leakage ofdissovled biogas in the system.

a

2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0A
0

CH4 th�c t�

% CH4
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0

50

100

150

200

250

300

T� l� khí CH4 (%)

Khí CH4 (L /d)

CH4 lý thuy�t

350

Ngày

Figure 3. Lượng khí sinh học tích lũy trong suốt thời gian vận hành mô hình,và tỷ lệ khí mê tan trong khí sinh học
It was observed that the methanogenic activity of suspended sludge increased withtime in this study. This implies that the active microorganisms are likely to besuspended growth rather than attached growth in AnMBR system. The otherreason could be the propensity of microorganisms to be suspended or attached.
Methanogenic bacteria had a higher tendency to grow in anaerobic fluidized bed
reactor than in a chemostat reactor (Araki and Harada, 1994). The environmental
conditions on the cake layer may not be favorable for attached growth due to theshear force by cross flow.

CONCLUSION
A laboratory-scale anaerobic membrane bioreactor system (AnMBR) was run
over the couse of one year to investifage the efficiency in treating domestic
wastewater in Hanoi. Results showed that at different hydraulic retention timeand organic loading, high and stable removal efficiency of organic matter COD(80-90%) and suspended solid TSS (95-98%) were achieved. Nitrogen content(TN, NH4-N) in the treated water was almost familiar with untreated sewage,
suggesting anaerobic processed coupled with membrane filtration does notremove nitrogen. In order to meet the stringent discharge consent

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ICUS Report 73(QCVN14:2008/MONRE or QCVN40:2011/BTNMT), the permeat from AnMBR
system needs to be undergone a further treatment for nitrogen removal. The
results show that AnMBR technology is suitable for treating domestic wastewaterin Vietnam condition. Treated wastewaters were of good quality and fit withWHO guidelines for agricultural reuse. In addition, AnMBR bring small footprint
advantadge which is very applicable in small urban areas and having difficulties
in sludge treatment.
This study was conducted under the research project financed by Vietnam
Minitry of Education and Trainning (B2012-03-03)
REFERENCES
1.

Araki, N., Harada, H., 1994. Population dynamics of methanogenic biofilm
consortium during a start-up period of anaerobic fluidized bed reactor.
Water Sci. Technol. 29, 361–368.

2.

Baek, S.H., Pagilla, K.R., 2006. Aerobic and anaerobic membranebioreactors for municipal wastewater treatment. Water Environ. Res. 78,
133–140.

3.

Ho J. Khanal, S.K. Sung, S., 2007. Anaerobic membrane bioreactor fortreatment of synthetic municipal wastewater at ambient temperature. Water
Sci. Technol. 55, 79–86.

4.

Jaeho Ho and Shihwu S. Methanogenic activities in anaerobic membranebioreactors (AnMBR) treating synthetic municipal wastewater. Bioresource
Technology 101 (2010) 2191-2196

5.

Munariatis I. D. and Grigoropoulos S. G. - Low-strength wastewater
treatment using an anaerobic baffled reactor” Water Environment Research,
74 (2002) 170-177.

6.

Sutton P.M., Bérubé P., and Hall E.R. - Membrane Bioreactors for
Anaerobic Treatment of Wastewaters. Final report- WERF Project 02-CTS4 (2004). Water Environment Research Foundation.

Anaerobic submerged membrance bioreactor (AnMBR) for decentralized municipal
Anaerobicinsubmerged
membrance bioreactor (AnMBR) for decentralized municipal. . .
wastewater treatment
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New Technologies for Urban Safety of Mega Cities in Asia

HAN-sense: A solution for traffic air
pollution monitoring in hanoi city using
wireless sensor networks
Phong Thanh BUI, Thieu Nga PHAM, Quang Duc LE, Nguyet Thi THAI,
Thuy Duong LE, Dang Hai HOANG1, Thorsten STRUFE2
Hanoi University of Civil Engineering, Information Technology Faculty, Vietnam
1
Ministry of Information and Communications, Vietnam
2
TU Darmstadt, Germany
ABSTRACTThe rapid growing of air pollution is one of the most challenging problems for alarge capital city like Hanoi today. Among various pollution sources, the exhaustgas from traffic system is the main cause of pollution. In order to help the city
authorities monitor air pollution, as well as to have early accurate warning about
urban environment hazard, a solution for urban-scale environment monitoring isnecessary. This paper presents our developed system, called HAN-Sense system,
which collects and visualizes traffic pollution data in Hanoi city. First, we
introduce the design of HAN-Sense based on a sensor network using ZigBee
wireless communication to collect the pollution data and briefly present our
proposed method for data transfer to a monitoring center. Second, we describe
how our monitoring center processes and visualizes measurement data to make itavailable online on a map-based web application. Finally, we present some resultfor pollution monitoring in an urban district of Hanoi city.
Keywords: Wireless sensor networks, pollution data monitoring, data collection
and forwarding, sensor calibration, data clustering and visualization.
1. INTRODUCTION
In urban areas, traffic is the largest source of pollution. According to statistics ofthe Ministry of Transport of Vietnam in 2010, air pollution in urban areas due totraffic activities is about 70%. Hanoi, the capital of Vietnam, is the second largest
city and most crowded city with high population of approximate 8 millions. High
traffic density is due to the growing urbanization and the continuous increment ofprivate vehicles, including mostly motorcycles. The air pollution generated bytraffic is becoming one of the most challenging problems that directly affect life
quality of citizens. The impact of air pollution is serious for peoples who daily get
into traffic jam on their motorbike without any protection. Urban-scale
environment monitoring is necessary to provide measured pollution data forfurther analysis to distinguish different pollution factors, for giving warnings andcorresponding countermeasures such as city planning, green plants, vehicle
emission control, etc.

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Pollution measurements are usually carried out using a number of static highprecision sensors. While this cannot cover large areas, simulations are used to
calculate pollution maps. This is both time consuming and expensive, andsystematically unable to provide real-time results with sufficient resolution in both
space and time. However, achieving real-time data is actually needed to allow any
useful warning system. Wireless sensor networks (WSN) technologies have been
widely adopted for environment monitoring (Khedol, 2010). Potential applications
were proposed to monitor urban environment with a set of parameters such as
noise, traffic density, temperature, air quality and exhaust gas concentration etc.
These applications enable governments to build up such smart cities that allow
detecting and controlling environment hazard (Wener, 2006). Although emergent
communication technologies have been proposed, they have not been adequately
applied in this area. There are several issues that should be further investigate for
effective implementations including choice of network topology for themonitoring area with limited number of sensors, impact of wireless channels, etc.
On the other hand, processing and visualizing dataset collected from WSNs is afurther important part of the whole pollution monitoring system. For dataprocessing and data visualization, several issues should be addressed including
sensor calibration for accurate measurements, evaluation of typical datasets foreach monitoring location, processing method, quality of visualization on a map.
This paper presents a solution for urban-scale pollution monitoring system called
HAN-Sense to collect and visualize traffic-generated pollution in Hanoi city.
HAN-Sense is based on a Wireless Sensor Network (WSN) using ZigBeetechnology and a method for data transfer from sensors to a monitoring center.
Moreover, HAN-Sense enables data pre-processing, sensor calibration, dataclustering and representation for online visualization on a map. Since Hanoi is avery large city, we select an urban district with high traffic density for our pilot
project. The paper is organized as follows. Section 2 presents motivation andrelated works. Section 3 outlines the design of HAN-Sense and the method of data
forwarding. Section 4 presents the issue of sensor data conversion and sensor
calibration. Section 5 focuses on data processing and visualization. Section 6presents our pilot project and finally, Section 7 concludes the paper.
2. MOTIVATION AND RELATED WORKSA WSN consists of a large number of sensor nodes, which are densely deployedin the environment. A WSN node contains one or more sensors for collecting
different environment parameters and several modules for processing and wirelesscommunications. WSN using IEEE 802.15.4 (ZigBee) standards have gained
prominence in recent years for environmental monitoring applications such as
traffic-generated pollution monitoring. However, how to collect pollution data in awide area only with a limited number of WSN nodes is remaining a practicalquestion due to the characteristics of mobile wireless environment and specificpollution monitoring requirements. A practical solution for pollution monitoringin a big city requires several issues to be solved.
A number of research projects tried to investigate various aspects of WSN

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applications for pollution monitoring (e.g. Da-Sense, Rescatame, PermaSemse,
OpenSense). Da-Sense proposed NoiseMap using a real-time noise sensing
application and a Web-based map for displaying noise density over Darmstadt
city. Rescatame is a smart city project developed in Salamanca, Spain forpollution monitoring and sustainable management of traffic. The PermaSense
project aims to gather environmental data on high-mountain permafrost in the
Swiss Alps. The OpenSense Zurich project is an emergent project for monitoring
air pollution aiming to increase public awareness of urban air pollution and to
involve general public into environmental monitoring. In general, these projects
use sensors mounted on trams and public buses to record air pollution andtransmit data to a server, either via a base station or 3G/GPRS. Several
challenging issues have been addressed including on-the-fly-calibration of sensors,calibration accuracy, measurement accuracy, detection and filtering of systematicand transient sensor errors, area coverage problem, routing selection. The mostdrawbacks of low-cost sensors are their limited accuracy and resolution. Thus, thesensors require frequently recalibration in order to provide precise pollution
recordings and to increase sensing accuracy.
3. DESIGN OF HAN-SENSE SYSTEM
Our HAN-Sense system for air traffic pollution monitoring consists of one server,
one base-station and a number of sensors. The sensors collect data fromenvironment and transmit them to the base station. Data from the base-station willbe transferred to, processed and visualized in the server. A problem is how tocollect data on the main roads in a large area with a limited number of sensors.
We solved the above problem by means of moving sensors on closed trajectories.
These trajectories are thoroughfares with concentrated traffic. Sensors cantransmit data only in a short distance (less than 100m) and the server needs toreceive data for processing after a certain period of time (e.g. 1 hour). Due tothese constraints, remote sensors cannot transmit data directly to the base-station.
Data should be transferred through intermediate sensors, which act as dynamic
bridges to forward data towards the base station gradually.
With this in mind, we designed our sensor network as follows. We divide themonitoring area by N trajectories. We require that at least one trajectory should bein the coverage of the base station. Moreover, any two trajectories should have atleast one overlapping road distance, so that WSN nodes are enable to transmit
data to each other. For collecting traffic pollution data, we use WSN nodes
equipped with various sensors. WSN nodes will move on these predefined
trajectories. Each WSN node will be assigned a level and a weight. The level ofeach sensor is determined as follows. If a sensor moves on trajectories in the basestation's coverage, its level is equal 1. If a sensor is in the coverage of anothersensor, its level is equal to the level of the sensor it meets plus 1. If a sensor meets
many sensors, its level is equal the smallest level of sensors it meets plus 1.
Sensors will frequently update their levels trending towards level improvement(lower level, level decreases as the sensor closes to the center, level=1 is theclosest to the center). Weight of each sensor is determined as follows. Initial value
A traffic
solutiontraffic air
pollution inmonitoring
HAN-Sense: HAN-sense:
A solution forairforpollution
monitoring
hanoi cityin hanoi city using wirelesssensor
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sent data to another sensor or the base-station, its weight increases by K. If asensor successfully receives data from another sensor, its weight decreases by 1. If
the weight becomes negative (<0), the level of this sensor needs to be reset to thelevel from beginning. This is the flexibility of the proposed method, helps tochange the level of a sensor, when it does not perform his duty as a bridge forreceiving and forwarding data, since negative weight means this sensor was notable to forward data, but only received data after a long time (depending on K).
The levels of sensors will be updated as follows.
1
if i sees the base stationLi   Lmin  1 if Li  1 & Lmin  0 or Li  Lmin
if Wi  0
 1

(1)

Where Li is the current level of node i, Wi is the current weight of node i, Lmin is
the minimum level of n neighbor nodes, L min  min L j .
jnLevel and weight are the important parameters for data forwarding, since data is
only forwarded from a WSN node with higher level to the one with lower level. If
a WSN node sees many WSN nodes having the same level, it will send data to thenode with higher weight. Our proposed method is called Adaptive Forwarding
Protocol.
4. DATA PRE-PROCESSING
4.1 Converting the read data
Sensor is a device for sensing various information and converts them into
electrical signals. There are many different types of sensors such as temperature
sensors, gas sensors, optical sensors, infrared sensors, etc. For traffic air pollution,
following typical sensors can be chosen: Carbon Monoxide (CO), Carbon Dioxide(CO2), Methane (CH4), Isobutane (C4H10), Nitrogen Dioxide (NO2), Ozone (O3),
Volatile Organic Compounds (VOC’s). Figure 1a shows a CO sensor mounted on
a WSN device (Libelium). Multiple sensors may be integrated into a WSN nodethat enables to set up parameters for each type of sensors. Measured values are
output voltages of sensors, whereas parameters for displaying gas concentration
are ppm (parts per millions). Thus, we must convert sensor output voltages to ppm.
We use the following equal for conversion (Libelium):

V .R
Rs  c L  RL or
Vout

Rs
V
 c 1RL Vout(2)

Where Rs is the sensor’s output resistance, Vc is its power, Vout is the output
voltage measurement and RL the load resistance. From measured Vout, we calculate
Rs (or Rs/RL). Based on conversion graph provided by the manufacturer, we get
the conversion formula. For linear graph of Vout and gas concentration, we use thefollowing formula:log( y )  m log( x)  b or1028

y  x m10b

(3)

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Where y = Rs/RL , x = gas concentration (ppm), m and b are coefficients that will
be calculated based on two points on the graph.
However, the graph is not always linear, e.g. for O3 gas concentration (Figure 1b).
For nonlinear graph, a small change of Vout will result in a major change of the gas
concentration.

Figure 1a: A WSN node with sensors. Figure 1b: Graph of sensitivity O3 sensor
The conversion performs by two steps: Graph digitizer and Regression. At thefirst step, a graph (in form of BMP, GIF, JPEG, PNG or XPM) is converted into
digital data. We use Windig tool (Windig) for this conversion. At the second step,
we use a Curve Fitting tool (MatLab) to get regression relationship of digitalizedgraph data. Possible regression models are linear regression, polynominal
regression and other nonlinear regressions. To evaluate the appropriateness of theregression model, we rely on the assessment of parameters R2 and SSE in fitting
functions. The best-fit approximation of the points in the dataset has been
extracted from the graph is the one with SSE close to 0 and R2 close to 1.
With dataset received after Graph digitizer, we use Curve Fitting tool for linear
regression with the function x=0.00664y+ 0.2213 as illustrated in Figure 2a. We
get SSE=0.9012 and R2= 0.985. If we use quardratic regression (Figure 2b), we
get SSE = 0.03232, and R2= 0.9995. The quadratic curve is better fit than thelinear regression. The conversion formula is: x = – 0.000003316y2 + 0.009712y –0.01193. The third-degree regression will approximate better (R2=1), but withmore complexity. Thus, we used quadratic regression.

Figure 2a: Linear regression.

Figure 2b: Quadratic regression

A traffic
solutiontraffic air
pollution inmonitoring
HAN-Sense: HAN-sense:
A solution forairforpollution
monitoring
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networks
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4.2 Sensor Calibration

We use low-cost sensors for our implementation, which have small size and aresuitable to install on public transport vehicle. However, the main drawbacks of
low-cost sensors are their limited accuracy, low stability and poor selectivity.
There is a deviation of measured values of the same sensor types at the same
location, thus, collected dataset may be unreliable. We should calibrate sensors toprovide approximate values for the same measurement at the same location.
Calibration process is carried out by modifying values of appropriate parameters
for each sensor. Certain parameters can be used for calibration, e.g. the Load
Resistance (LR) parameter for Carbon Monoxide sensors TGS2442 provided by
Figaro company (Figaro, 2007).

Figure 3: Calibration for three sensors using load resistance (LR)
Figure 3 illustrates the calibration for three sensors using LR parameters. We
collect data in term of voltage and use the same LR parameters for three sensors
to calculate the gas concentration values (ppm value). As depicted in Figure 3b,
data values of sensor 2 and sensor 3 are adjusted by modifying the LR parameterto the values of sensor 1, approximately. In general, we do measurements with all
deployed sensors in the same time interval and the same environment condition inorder to calculate the average measured value. We determine the LR parameterfor each sensor so that the deviation of measured value and the calculated averageis less than a given threshold. Using this calibration method, the deviation can beevaluated by the mean absolute error.
5. DATA PROCESSING AND VISUALIZATION
5.1 Data Clustering

Raw measured data may be incomplete, incorrect or unreliable due to several
reasons such as GPS position information missing, error-prone data transmission.
For further analysis, measured data should be processed. As mentioned in Section
2, data objects may be complex for a location. For online visualization on map,
there is a need to evaluate typical measurement value for each location in a certain
period of time. Thus, we propose a clustering method for grouping similar data
objects into the same group of data. Each data point in measured dataset consistsof spatial attributes (latitude, longitude), timestamp, and gas concentration value.
The clustering method, therefore, should consider both the density of data objects
as well as the spatial limitation of each group.

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According to (Kaufman, 1990) two basic clustering algorithms can be used,
namely partitioning and hierarchical. Hierarchical algorithm creates a hierarchicaltree, called dendrogram, in which each node is a subset of dataset (a cluster) andevery leaf only has one instance. Partitioning algorithm creates a partition with kclusters from n-instance dataset. The most popular partitioning algorithm is Kmeans (Miller, 2009), which seams to be a better choice for large dataset incomparison with hierarchical algorithms. Thus, we decided to use K-Means forour data clustering. However, it is difficult to determine k, particularly for verylarge spatial dataset. Inappropriate choice may result in a poor partition. Moreover,
if we set a limit for cluster’s radius, then finding an appropriate k is more difficult.
To this end, we propose an algorithm called Limited-Distance-K-means based on
K-means, in order to determine parameter k and initial clusters that have radiusless than a given distance value with an acceptable computational complexity.
This Limited-Distance-K-means algorithm includes two stages. First, we create
set S of k initial clusters. Second, we make adjustment to set S to remove
unnecessary cluster with a modified K-means algorithm. After the first stage ofalgorithm, number of cluster can be large because of arbitrarily choosing instancefrom dataset. Subsequent instance tends to be selected into new cluster. Therefore,
we can make clustering more effectively by modifying K-means algorithm toremove a cluster if all of its instance can be assigned to the other clusters.
5.2 Data Visualization

For online visualization, we organize measured data into sets of data points, where
each point represents a pollution level in a certain location with latitude, longitude
and measurement time. Each data point will be a colored cell on a map. The cells
may be dense on traffic roads or sparse on the other areas depending on thedataset. In order to represent pollution independently of density of data points,
hexagonal grid is used to divide the entire monitoring area into hexagonal cells.
Cells in a hexagonal grid are aligned along three axes rather than just two in arectangular grid. Thus, the outlines of groups of cells in a hexagonal grid can form
more varied, less rectilinear shapes than groups of cells in a rectangular grid
(Birch, 2007). Moreover, hexagon shape is closer in shape to circle than square.
This characteristic is useful when determining how to get value point for applying
interpolation. Instead of to determine which data points inside hexagonal cell, we
just need to find data points inside the circumcircle of hexagonal cell.
For determining value of each cell, we apply Inverse Distance Weighted
interpolation method (Donald, 1968). The inverse distance weighted procedure isversatile, and is fairly accurate under a wide range of conditions for visualizing
pollution data. Value of target point is can be interpolated by observations in thefollowing equation:
1np ( x0 )  i 1 d  p ( x i )in1

 i 1 d (4)iWhere p(x0) is the interpolation value, di is the distance from known point xi to theunknown point x0, α is power parameter, n is the total number of known points
used in interpolation. The choice of power parameter α is arbitrary, but the mostA traffic
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popular choice is 2. With each hexagon cell, we assume the value of cell is valueof center point of cell. If we connect center point of each cell to center points of
all neighbor cells, we can construct a triangular grid from hexagon grid (Figure 4).
Hence, calculating values of hexagon cells turns into interpolating grid points on
triangular grid. In order to interpolate value for grid point x0, we need todetermine set of data points surrounding x0 involved in the interpolation. Denote r
is the max distance from a data point xi to x0, we determine r = d x l, where l is the
spread level. For online visualization of measured data on map, we developed a
website using Google Map service. Figure 5 shows pollution levels on a map
region with different values of d and spread level l.

Figure 4: Determination of radius r by parameter lFigure 5: Visual effects by changing d and l
6. THE PILOT PROJECTThis Section presents the implementation results of HAN-Sense system for air
traffic pollution monitoring in an urban district of Hanoi city. Hai Ba Trung is oneof the two districts of Hanoi city that have highest traffic density. There are morethan seventy-five thousands of resident families in which each own has at least
two motorbikes. Besides, many personal vehicles come from other regions since
Hai Ba Trung district has a complex of a garment industry park, two river ports
and three largest universities including Hanoi University of Science andTechnology, University of Civil Engineering and National University of
Economics. Recently, high traffic density in this district is said to cause severe air
pollution that makes a serious impact on local resident. At intersections thatfrequently have traffic congestion, exhaust emissions are usually very high.
Therefore, we choose streets with large traffic density to set up a pilot project.
The HAN-Sense system was tested using a ZigBee mesh network consisting of a
Meshlium base station and 8 Waspmotes (Libelium). These Waspmotes act as
WSN nodes, moving on 8 trajectories in order to cover Hai Ba Trung district withan area of about 14.6 km2 (Figure 6a). The trajectories have been designed so thateach mote can meet at least one other mote in an enough time to be able to send1032

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the data and two of the trajectories have some parts, on which Waspmotes canmeet the Meshlium. Each mote runs on a trajectory and is numbered according to
the trajectory number. We choose to measure CO gas concentration, since CO is atypical exhaust gas generated from traffic. CO is also classified as toxic gas thatcan seriously damage people health. During measurement time, each sensor is
attached on a volunteer motorcycle running at the speed of 10 km per hour.
Measurement value is captured from CO sensor for every 30 seconds, and thenstored on local storage. The Carbon Monoxide TGS 2442 sensor is mounted on
Waspmote, which is a compact, versatile and high mobility device, developed byLibelium. Parameters of each sensor are chosen to ensure the mean absolute error
from the standard sensor must not exceed 1.5 ppm threshold.

Figure 6a: Implementation with 8 trajectories. Figure 6b: Pollution data on map
Every hour, our server receives thousands of measurement records of data. We
applied a Limited-Distance-K-means algorithm for clustering data and we could
find out typical values for each location every hour using this algorithm. The
locations are separated from each other by a distance of radius about 50m. Graphin Figure 7a shows the difference of CO concentration levels at different times,
particularly in comparison with peak hour. Graph in Figure 7b indicates thedifference of concentration measured at different positions along a street. Levelsof CO gas at intersections, which are represented by point 1, 2, 3 in Figure 7b, aresignificantly higher than those at other position.

Figure 7: CO Concentration at different times (a) and different positions (b)Measurement data collected from all 23 streets on 8 routes have been processedand visualized on an online map available at http://han-sense.vn (Figure 6b). The
level of pollution, explicitly based on CO concentration, is represented by a rangeof colors on map in which each color matches with a certain value ofconcentration. User will be able to choose options that display measurement databy a certain time period, as well as by type of gas. Currently, we only measure CO
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measurement data on a public website does help user have more useful
information about air traffic pollution.
7. CONCLUSION

The paper presented our HAN-Sense system for air traffic pollution monitoring.
We described the design of HAN-Sense based on a WSN using ZigBeetechnology to collect pollution data and an adaptive data forwarding method totransmit data to the server. We addressed several issues such as data conversion
from voltages to ppm, sensor calibration, data processing and online visualizationof pollution data on a map. We implemented and tested our proposed systemusing a ZigBee network with one Meshlium base-station and eight WSN nodes tomonitor an urban district of Hanoi City.
We would like to thank the Alexander von Humboldt Foundation (Germany) for
the supports to this research work.

REFERENCES

Birch, C.P., Sander, P.O., Beecham, J.A., 2007. Rectangular and hexagonal grids
used for observation, experiment and simulation in ecology. Ecological modelling
206 (2007), p.347–359.
Da-Sense, 2011. Monitoring system for Smart cities. Project of TU Darmstadt,
Germany. http://www.da-sense.de.
Donald, S., 1968. A two-dimensional interpolation function for irregularly-spaced
data. Proceedings of ACM National Conference. p. 517–524.
Figaro, 2007. Technical Information for Carbon Monoxide Sensors. Figaro
Company. http://www.figarosensor.com/details.html.
Francesco, M., Das, S., 2011. Data Collection in Wireless Sensor Networks with
Mobile Elements: A Survey. Journal ACM Trans. on Sensor Networks, Vol.8, Iss.
1, Aug.2011, NY, USA.
Kaufman, L., Rousseeuw, P.J., 1990. Finding Groups in Data-An Introduction to
Cluster Analysis. John Willey & Sons, p.37-38.
Khedol, K. K., Perseedoss, R., Mungur, A., 2010. Wireless sensor Network Air
pollution Monitoring system. International journal of wireless and mobile
networks, Vol.2, No.2.
Libelium, Waspmote datasheet version v.4.2, Libelium Technical Doc., 4/2013.
Matlab, http://www.mathworks.com/products/curvefitting/.
Miller, H.J., Han, J. (Editor), 2009. Geographic Data Mining and Knowledge
Discovery, 2nd Edition, Chapman & Hall/CRC Data Mining and Knowledge
Discovery Series), p.156-157, 170-173.
OpenSense. Open sensor networks for air quality monitoring. Project of ETH
Zurich and EPF Lausanne. http://data.opensense.ethz.ch
PermaSense, 2009. PermaDAQ: A scientific instrument for precision sensing anddata recovery in environmental extremes. Internl. Conference on Sensor Networks

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ICUS Report 73(IPSN), IEEE Computer Society, pp.265-276.
Rescatame, 2012. Pervasive Air-Quality Sensors Network for an Environmental
Sustainable Urban Traffic Management. project report.
Shah,K., Francesco,M., Anastasi,G., Kumar,M.,2011. A Framework for ResourceAware Data Accumulation in Sparse WSNs. Computer Communications, Vol.34,
Issue 17, Nov. 2011, pp. 2094–2103.
Wener, A.G., Lorincz, K., Ruiz, M., Marcillo, O., Johnson, J., Lees, J., Walsh, M.,
2006. Deploying a wireless sensor network on an active volcano, Data-Driven
Applications in Sensor Networks. IEEE Internet Computing (Special Issue),March/April 2006.
Windig, http://www.unige.ch/sciences/chifi/cpb/windig.html.

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Towards sustainable transportation throughintroduction of eco-drive management
system for vehicle fuel efficiency
1,

Dinh Van HIEP 1, Manabu OHNO 2, Yosui SEKI 3
PhD. Director, Institute of Planning and Transportation Engineering, National
University of Civil Engineering, Room 208, Laboratory Building, No. 55,
Giaiphong str., Hanoi, Vietnam
hiepdv@ipte.com.vn
2,3
ALMEC Corporation, 1-19-14 Aobadai,

ABSTRACT:
Sustainable transport development is a key factor for supporting economic
development and growth, and facilitating the exchange of goods. However,rapidly increasing emissions of carbon dioxide from the transport sector,
particularly in urban areas, is a major challenge to sustainable development indeveloping countries. In order to reduce CO2 emission of automobiles, promotionof ecodriving is considered being effective. Ecodriving is a well-established,affordable and simple behavioral change intervention, which could reduce fuelconsumption between 5 to 25% according to different situations. In this paper,
Eco-drive Management System (EMS) was first introduced through a case study
in Vietnam. The findings may help to realize the effectiveness of eco-drive towardsustainable transportation in Vietnam as well as to promote the countermeasures
for the global warming issue. In addition, some major issues have been discussed
for further studies of ecodriving and for introduction of fuel efficient vehicles.
Keywords: GHG emissions, Sustainable transportation, Fuel efficiency, Fuelconsumption, Eco-drive management system, Vietnam.

1. INTRODUCTION
Sustainable transport development is a key factor for supporting economic
development and growth, and facilitating the exchange of goods. At the same time,transport industry and vehicle are major emitters of gaseous and particulate
pollution in urban areas which have serious health effects, including respiratory
and cardiovascular diseases. The transport sector remains one of the main sourcesof CO2 emissions from 10 – 25% in most countries (EEA, 2008; Timilsina andShrestha, 2009). Ecodriving is a well-established, affordable and simple
behavioural change intervention, which could reduce fuel consumption between
10 to 20% (Barth and Boriboonsomsin, 2009). Ecodriving attempts to change
drivers’ behaviour through advice such as driving more smoothly by anticipatingchanges in the traffic, shifting gear sooner, operating the vehicle within an
optimum range of engine revolutions or with operating speed range, avoiding
jerky braking/acceleration and avoiding traffic congestion. Many countries havepromoted ecodriving in “Green Transport” as a key element of national strategies1037

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to reduce CO2 emissions (ECODRIVEN, 2009; JAPE, 2012) towards sustainable
development.
Ecodriving strategies can be classified more specifically. Driver training andadvice can be called static ecodriving with limited feedback. Next, ecodriving
based on instantaneous vehicle performance display fuel economy in real-time,with a growing number of such devices used in vehicles today. Finally, dynamic
ecodriving adds to instantaneous performance with real-time advice or feedback,such as speed management suggestions based on roadway geometries orcongestion. CE-CERT (2011) has recently conducted dynamic ecodriving studies
on highways and arterials and found significant reductions in fuel use (13%reduction on highways, 12% reduction on arterials) and CO2 emissions (12% on
highways, 14% on arterials), while maintaining similar travel times. However,
ecodriving research in Vietnam has never been studies so far.
Given the merit of ecodriving towards sustainable transportation, theobjective of this paper is to introduce Eco-drive Management System (EMS) in
order to reduce vehicle fuel consumption as well CO2 emission through a casestudy in Vietnam. In the following sections, eco-driving along with EMS is firstpresented, then overview of transport situation and CO2 emission from transport
sector in Vietnam, which is followed by a case study demonstrating the
introduction of EMS in Vietnam. Taxi vehicles are employed in the study withdifferent traffic situations in center and suburban areas of Hanoi city.

2. ECO-DRIVE MANAGEMENT SYSTEM
2.1 Overview of Ecodriving
Ecodriving consists of changing driving behavior to maximize the fuel economy
of existing cars and trucks while minimizing carbon emissions. It is a modified
way of driving that is best suited for modern engine technology, taking into
account various driving conditions. Ecodriving research and programs can take on
many forms, ranging from providing basic advice such as anticipating changes intraffic, smoother acceleration and braking, and proper vehicle maintenance, all theway to receiving real-time information on how to drive in current traffic
conditions, or what route to take. Ecodriving offers numerous benefits, including
greenhouse gas (GHG) emissions reductions, fuel cost savings, as well as greater
safety and comfort. Fuel reduction through applying ecodriving can be obtained
up to 20 or 25% in most studies (Rakotonirainy et al., 2012; ECCJ, 2012). Figures
1 and 2 present driving patterns a long with the benefit of ecodriving according todriving patterns in different stages below.
1. When starting and accelerating: accelerate taking around 5 seconds toreach 20km/h then conduct further acceleration smoothly.
2. When driving: drive while watching in front and maintain a wide spacefrom the car in front to prevent changes in speed.
3. When decelerating and stopping: remove your foot from the accelerator
early and endeavour to drive stably.
4. When stopped: engage neutral gear and use the side brake. If possible,
eliminate idling by stopping the engine.

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Source: ECCJ (2012)

Figure 1. Driving patterns of ecodriving

Time

Source: ECCJ ( 2012)

Figure 2. Effects of ecodriving according to driving patterns
2.2 Eco-drive Management System
Eco-drive management system (EMS) is used for evaluating effectiveness of
ecodriving and for dynamic ecodriving to display instantaneous performance withreal-time advice or feedback. EMS application on smart-phone are used to collectand display the fuel consumption (FC) and other drive situation data (DSD) in realtime. Using popular smart-phone as the EMS device offers inexpensive andeffective eco-drive to vehicle users in developing countries. The On Board
Diagnosis II (OBD2) (as a Bluetooth device) is installed in a connecter in the car.
The data scanned in the connecter are transmitted to smart-phone by Bluetooth(wireless). Smart-phone used in EMS is an application of Android smart-phonewith a EMS software developed by ISHIDA R&D. The EMS device help driver topractice eco-drive by in real time displaying the drive situation and notice forsudden acceleration or braking by alarm sound, including instantaneous fuelconsumption, average fuel consumption, acceleration, GPS location, Eco-drive

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diagnosis point. The total of 55 types of data will be displayed and collected
through EMS as shown in Figure 3.

a) OBD2 scannerb) EMS device(Smartphone)
Figure 3. Outline of EMS devicec) FC and DSD
performance

3. VEHICLE TREND AND TRANSPORT CARBON EMISSION IN
VIETNAM
3.1 Vehicle Registration in Vietnam
Vietnam is one of the countries which is using motorcycle as a primary vehicle.
The number of registered motorcycle has significantly increased within 10 years.
According to statistics by Ministry of Transportation (MOT) from 2005-2011, thenumber of motorcycle is increased up to 2.05 times as shown in Figures 4. In theend of 2010, newly-registered cars account for 4% of registered vehicles, newlyregistered motorcycles account for 96%. However, the number of car registration
significantly increased in major cities such as Hanoi and HCMC during recent
years. Before the year of 2006, a number of registered cars in Hanoi slowly
increases, but from 2007 to present registered cars are rapidly increasing because
the price of car gets closer to people’s affordability, even though total various tax
is accounted for more than 200%. The fast growth of registered car in Hanoi isshown in Figures 5. Hanoi is one of the two cities (i.e., Hanoi and HCM cities) in
Vietnam with the largest number of registered car, to the end of 2010, the numberof registered car is 380,000 cars accounting for 1/6 of cars in nationwide.

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Source: The National Safety Traffic Committee, 2009; Ministry of Transportation, 2012.

Figure 4. Vehicle registration number in Vietnam

Source: Hanoi Traffic Police, 2011

Figure 5. Number of registered car in Hanoi

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3.2 Carbon Emissions from Transport Sector in Vietnam
Rapidly increasing emissions of carbon dioxide from the transport sector,
particularly in urban areas, is a major challenge to sustainable development indeveloping countries. The World Bank (Timilsina and Shrestha, 2009) has
analyzed the CO2 emissions growth of transport sector in selected developing
Asian countries during 1980–2005. Figure 6 shows the trend of transport sector
CO2 emissions of selected countries in Asia. The transport sector remains one of
the main sources of CO2 emissions in most countries in Asia, while rising incomesa long with higher levels of car ownership (Webster et al, 1986a,b) and greater
trip rates/distances (Schäfer, 2000) has resulted significant increase of CO2
emissions in transport sector in these countries.

Source: IEA (2007)

Figure 6. Trend of transport sector CO2 remissions in Asia
National CO2 emissions in Vietnam have increased from 14 million tons in1980 to 80 million tons in 2005, while the transport sector’s share of thoseemissions has almost doubled from 14% to 25% as indicated in Table 1. In 2005,
looking at different transportation modes, road transport accounted for the bulk of
CO2 emissions with 91.95%; other modes were air (2.5%), water (4.8%), and rail
(0.8%) as illustrated in Figure 7. Therefore, any attempt to address climate change
in Asia must pay attention to transport sector emissions, especially for roadtransport.
Table 1. CO2 emission mix by sector

Source: IEA (2007)

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ICUS Report 73a) Modal mix for passenger transportb) Modal mix for freight transport

Source: IEA (2007)

Figure 7. Modal mix for passenger and freight transport in Vietnam
The analysis splits the annual emissions growth into components
representing economic development; population growth; shifts in transportation
modes; and changes in fuel mix, emission coefficients, and transportation energy
intensity (which is the ratio of total fuel consumption for transportation in an
economy to its gross domestic product). The World Bank study finds that of thesix factors considered, three—economic development, population growth, andtransportation energy intensity—are responsible for driving up transport sector
CO2 emissions in Vietnam. Transportation energy efficiency is the ratio of total
fuel consumption for transportation in an economy to its gross domestic product.
This value has slowly started to decline in Vietnam starting in about 1996, i.e.,
fuel consumption for transportation has declined per unit of economic output.
However, of the 11 countries in southeast Asia for which data are presented,
Vietnam has the second highest transportation energy inefficiency, trailing only
Malaysia (Figure 8a). In effect, the high inefficiency of fuel consumption relative
to economic output in Vietnam contributes to its rapid growth in CO2 emissions
from the transport sector as clearly presented in Figure 8b.

a) Transportation energy intensity in selected Asian b) Transport sector CO2 emissions
countries (1980-2005)
growth and driving factors in
Vietnam
Source: IEA (2007)

Figure 8. Transportation energy intensity and transport sector CO2 emissions
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4. CASE STUDY
4.1 General Information
Road transport has been recently developed rapidly due to the economic
development in Vietnam. As a result, emissions of carbon dioxide from the roadtransport causes a major challenge to sustainable development for the country.
Realizing this problem, ecodriving employed EMS has been considered as anadvanced low-carbon technology through a the Bilateral Offset Credit Mechanism(BOCM) in order to achieve reduction of GHG emissions. Japan Global
Environment Centre Foundation (GEC, 2012) has firstly introduced a project ofimprovement vehicle fuel efficiency through application of EMS for taxies in
Hanoi. The implementing procedure for the project is shown in Figure 9. The casestudy of this paper is to employ main input data and result from GEC’s projectfor its analysis and discussion as in following sections.

Source: GEC, 2012

Figure 9. Organizational chart for project implementation
4.2 Study Routes
Two routes, in city centre and suburban areas, will be used for training and fieldobservation of ecodriving study as illustrated in Figure 10. Table 2 showsdifferent traffic situations in these two areas in terms of average travel speed andaverage fuel efficiency which was collected and analysed by using EMS device
with GPS driving trace.
Table 2. Average travel speed and average fuel efficiency
Item
Unit
CentreSuburbanTraffic situation
Congested
Uncongested
Average travel speed
km/h
15.6
29.2
Average fuel efficiency litter/100km
6.7
5.2

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Centre area (4km)Suburban area (4km)
Figure 10.Routes of the case study
4.2 Selected Vehicle Type
Taxi operators have been rapidly increased with accelerating urbanization andmotorization in big cities such as Hanoi and HCMC due the lack of adequate
public transport means. Figure 11 illustrates the increasing trend of taxi number in
Hanoi city in recent years. The number of taxi slowly increases in Hanoi from
2,000 cabs in 2003 to 2,600 cabs in 2006 equivalent to 200 cars per year in
average. However, up to November 2007, the number of taxi was significantly
doubled from 5,000 cabs to 9,000 cabs in 2008. In a short time from the end of
2009 to April 2010, the number of taxi cabs increases sharply from 12,000 up to
14,000. The growth rate is still maintained until now, the number of taxi cabs in
Hanoi is 15,000 in March 2011 and 17,500 in April 2012. Figure 12 shows the listof taxi brands and taxi businesses in Hanoi, total of 114 registered companies, andthe average number of taxi cabs in each taxi company. Taxi Group is presented asa biggest company with a larger number of taxi cabs, responsible for about 63% of
total taxi cabs operating in Hanoi city. Given the fact, the study select Taxi Groupfor the case study with the vehicle of 4-seat Toyota Vios as the most popularvehicle in Hanoi’s taxi operators.
20000
16000
12000
8000
4000
0
2005

2006

2007

2008

2009

2010

2011

2012

Source: ALMEC-IPTE (2012)

Source: ALMEC-IPTE (2012)

Figure 11. Growth of registered taxi in Hanoi

Figure 12. Number of cabs in eachcompany

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4.3 Analysis Procedure
The procedure for the study will be the following stages: (1) collection andanalysis of the taxi operation data before the EMS introduction; (2) collection andanalysis of the taxi operation data after installing EMS devices into studied cabs;(3) carrying out Eco-Drive Training Program based on the Japanese know-how;(5) implementing eco-drive in practice and collecting fuel consumption as wellcarbon emission; and (6) estimating for vehicle fuel efficiency and carbon
emission reduction. Figure 13 shows the procedure of the eco-drive study.

Figure 13. Procedure of the eco-drive study

5. ANALYSIS RESULTS AND DISCUSSIONS
5.1 Analysis Results
A designated course was cruised twice by taxi drivers, once in the normal manner(without project activity) and once in the eco drive mode. Number of participantsis 6 and 16 for city center and suburban areas, respectively. The driving
experience in city center is more than suburban area (due to the difficult driving incongested traffic in Hanoi center) which is 5.4 and 4.5 years in average
respectively. The driving performance was recorded for comparative analysis as
example illustrated in Figure 14. In the suburban course, cruising was without
interruptions of traffic congestion while in inner city course the cruising was intraffic congestion mixed with other automobiles and motor cycles. After
collecting data and carrying out analysis, average fuel reductions are obtained
about 6.0% and 2.0% in suburban and inner city courses, respectively. Figure 15
shows the comparative data analysis of fuel consumption in the normal and ecodrive modes (GEC, 2012).

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Figure 14. Comparative analysis record before and after applying eco-drive mode

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Figure 15. Fuel consumption analysis before and after applying eco-drive mode
5.2 Discussion of Eco-drive Issues
The aggregated average fuel reduction obtained in the study is not high as
expected as well in comparison with other studies (e.g. ECODRIVEN, 2009;
MRPI, 2011; Rakotonirainy et al., 2012; ECCJ, 2012). Furthermore, there is asignificantly difference between city center and suburban areas. Main reasons
have been primarily observed from the study, i.e. traffic situation, driving
environment such as an inference of traffic flow by motorcycles, personal
motivation, driver experience, vehicle quality. In the following, some major
remained issues for further consideration are overviewed:o When driving in a crowded urban area, it can be difficult to maintain asteady speed (e.g. keeping rolling in traffic) with a high gear, and safety
should be prioritized by adopting a low speed although it is not fuelefficient. This matter is one of reasons that ecodriving is not so effective incity center of Hanoi where traffic is heavily congested.
o An experienced driver may understand easily that the best compromise
depends on the situation, but it should be noted that driving habits learned
by experience could also hard to change. Therefore, during a short time oftraining in this study, it is difficult for experienced drivers to change theirhabits and follow ecodriving technique exactly.
o Most drivers had an immediate fuel consumption improvement that was
stable over time but some tended to fall back into their original drivingstyle. Eco-driving style is difficult to turn into driving habit as it isdependent to the driving situation such as traffic, environment andpersonal motivations (Dogan et al., 2011). It points out that training is oneof important ways to constantly improve driver skills related to ecodriving
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technique. In Vietnam, ecodriving as a new introduction and its guideline
should be added into instruction of driving license.
o Time saving is an issue when considering eco-driving (Dogan et al., 2011).
CE-CERT (2011) has recently conducted dynamic ecodriving studies onhighways and arterials and found significant reductions in fuel use, while
maintaining similar travel times. However, further studies need for
differently cultural, technical, and educational barriers inhibiting the
adoption of eco-driving practices in order to promote ecodriving.
o Open research questions and challenges include providing drivers withdynamic traffic information through limited infrastructure, incentivizing
manufacturers to install ecodriving feedback devices into automobiles, andfurther analyzing driver behavior and distraction. Ecological Driving
Assistance Systems (EDAS) and Intelligent Speed Adaptation (ISA) will
become a standard part of future driving assistance systems. The
heterogeneity of vehicles, the complexity of the driving task andvariability of driving style will require simple advices through the use ofaggregated indicators to safety and ecology.

5. CONCLUSIONSThe study has implemented the eco-drive training program and thereby
established the procedure from the preparation of the curriculum and the text to
the implementation of training in Vietnam. The study has ascertained the positiveeffect of the eco drive activities on vehicle fuel efficiency improvement. The
findings have shown that the average fuel reduction are about 6.0% and 2.0% in
suburban and inner city courses, respectively. Although the reduction results are
not so high, it shows a potential for introducing ecodriving as a friendly
environmental technique to road transport system towards GHG improvement.
Furthermore, the study carried out in a short time and limited areas as well notconsidering various factors effecting the eco-drive measure. Therefore, it need tofurther study to find the effective measure of introducing eco-drive into Vietnam
according to its different traffic situations, driving environment, personal
motivation, driver experience, vehicle quality and types (including trucks andbuses). Other issues need to be simultaneously considered along with ecodrivingsuch as safety, travel time, relationship between fuel consumption and emissionthat gaining optimal benefits. Continuous actions should be put on ecodriving on
both training, practice and operating management strategies in Vietnam to achievea goal of CO2 reducion as well sustainable transportation, as referring to Japaneseexperience when its 2010 goal of reducing CO2 emissions by 31 million tons
below 2001 levels by encouraging drivers to use their vehicles more efficiently
through Eco-driving (Transport America, 2010). Given merits of available
advanced technologies, fuel efficient vehicles such as hybrid cars proposes a
promising alternative which integrated safety and ecology driving assistance, i.e.
Ecological Driving Assistance Systems (EDAS) and Intelligent Speed Adaptation(ISA).

Towardstransportation
sustainable transportation
through introduction
eco-drive management
Towards sustainablethrough introductionof eco-drive ofmanagement
systemsystemforvehiclefuelefficiency
for vehicle fuel efficiency

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ACKNOWLEDGEMENTS
The authors would like to express acknowledgement to Japan Global Environment
Centre Foundation (GEC), Japan Energy Conservation Center (JECC),
Department of Environment of Ministry of Transport (MOT)-Vietnam, Hanoi
Taxi Group (HTG), ALMEC Corporation-Japan, Institute of Planning andTransportation Engineering (IPTE)-Vietnam, Ishida R&D-Japan for theircooperation and providing materials for the study.

REFERENCES
ALMEC-IPTE (2012). Final Report of Data Collection and Analysis for
the Study of Eco-Drive under BOCM in Hanoi. ALMEC CorporationJapan & Institute of Planning and Transportation Engineering (IPTE)Vietnam.
Barth M., Boriboonsomsin K. (2009), Energy and Emissions Impacts of a
Freeway-based Dynamic Eco-driving System, Transportation ResearchPart D: 14(6). The Interaction of Environmental and Traffic Safety
Policies, 400-410.
CE-CERT (2011). Dynamic Ecodriving. Center for Environmental
Research and Technology. Berkeley, CA.
Dogan E.B, Steg L., Delhomme P. (2011). The Influence of Multiple
Goals on Driving Behavior: the Case of Safety, Time Saving, and Fuel
Saving. Accident Analysis Prevention.
IEA (2007). Database Vol. 2007. International Energy Agency (IEA).
Paris, France.
ECODRIVEN (2009). ECODRIVEN Campaign and Catalogue forEuropean Eco-driving & Traffic Safety Campaigns – Intelligent Energy
Europe (ecodrive.org).
ECCJ (2012). Ecodriving Guidelines. Energy Conservation Centre in
Japan. Tokyo, Japan.
EEA (2008). Energy and Environment Report 2008, European
Environment Agency, Copenhagen, Denmark.
JAPE (2012). Japan Association for Promotion of Eco-drive. Tokyo,
Japan.
GEC (2012). Final Report of Improvement of Vehicle Fuel Efficiency
through Introduction of Eco-Drive Management System(EMS).
Feasibility Study Program on Bilateral Offset Credit Mechanism(BOCM). Global Environment Centre Foundation (GEC)-Japan;
ALMEC Corporation-Japan & Institute of Planning and Transportation
Engineering (IPTE) - Vietnam.
MRPI (2011). Final Report of the Proceedings, UC-MRPI 2011 Ecodriving Workshop, Claremont Hotel, Berkeley, CA
Rakotonirainy, A., Haworth, N., Saint-Pierre, G. (2011). Research Issues
in Eco-driving. Queensland University of Technology and FrenchInstitute in science and technology of transport.
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Schäfer, A. (2000). Regularities in Travel Demand: an International
Perspective. Journal of Transportation and Statistics, 1–31.
Shaheen, S.A. (2011). Eco-driving Research at Transportation
Sustainability Research Center (TSRC). Final Report of theProceedings of the UC-MRPI 2011 Eco-driving Workshop, Claremont
Hotel, Berkeley, CA
Timilsina, G.R., Shrestha, A. (2009). Why Have CO2 Emissions Increasedin the Transport Sector in Asia? Underlying Factors and Policy Options.
Policy Research Working Papers 5098. The World Bank, Washinton
D.C.
Transport America (2010). Smart Mobility for a 21st Century America
Strategies for Maximizing Technology to Minimize Congestion,
Reduce Emissions and Increase Efficiency – Transportation America,
ITS America, US.
Webster, F.V., Bly, P.H., Johnson, R.H., Dasgupta, M., (1986a). Part 1:
Urbanization, Household Travel, and Car Ownership. Transport
Reviews, 6 (1), 49-86.
Webster, F.V., Bly, P.H., Johnson, R.H., Dasgupta, M., (1986b). Part 2:
Public Transport and Future Patterns of Travel. Transport Reviews, 6(2), 129-172.

Towardstransportation
sustainable transportation
through introduction
eco-drive management
Towards sustainablethrough introductionof eco-drive ofmanagement
systemsystemforvehiclefuelefficiency
for vehicle fuel efficiency

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Compressive strength of ordinary andbridge high performance steel plates:
Proposal of nominal design value andcorresponding partial safety factor
1

Viet Duc DANG1, Yoshiaki OKUI2Engineer, Institute of Transportation Science and Technology, Hanoi, Vietnam
dangviet.duc@gmail.com
2
Professor, Dep. of Civil and Environmental Eng., Saitama University,
Saitama, Japanokui@mail.saitama-u.ac.jp

ABSTRACTThe current Japanese design equation for load-carrying capacity of compressive
steel plates is examined for four conventional steel grades and new bridge highperformance steel grades SBHS500 and SBHS700. The analysis results of FEM
plate models with initial imperfections show that the current Japanese design
specification is un-conservative within the range 0.5<R<0.75 and overconservative in the range R>0.8, where R is the slenderness parameter. Statistical
distribution of the normalized compressive strength is obtained by means ofMonte Carlo simulation in combination with the response surface which is
obtained from sufficient number of FEM plate model analyses. Both initialdeflection displacement and residual stress are considered as sources ofvariability. The mean values of normalized compressive strength in this study are
similar to those obtained from experimental tests (Fukumoto and Itoh, 1984). The
standard deviation of the current study exhibits about half of the experimental
results (Fukumoto and Itoh, 1984) within the practical range 0.6<R<1.2. For thenominal strength is set to be equal to compressive strength mean value, themaximum partial safety factor results in 1.11, 1.13, and 1.16 corresponding to
non-exceedance probabilities of compressive strength equal to 5.0, 3.0, and 1.0%,
respectively.
Keywords: bridge high performance steels, compressive strength, residual stress,
initial deflection, local buckling.
1. INTRODUCTION
Box columns and box plate girders consisting of unstiffened steel plates arewidely used in bridge structures. The local buckling strength of the steel plates
frequently governs the load-carrying capacity of these structural elements.
The current compressive strength design equation for unstiffened plates inJapanese Specifications for Highway Bridge (JSHB) version 2002 has beenoriginally proposed in JSHB (1980). This equation was based on experimental1053

October
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Hanoi,Hanoi,
Vietnam0ctober
Vietnamdata for normal steel with yield strengths mainly less than 450 MPa. The bridge
high performance steels, which poses high yield strength and good weldability,
have been standardized since 2008 as SBHS500 and SBHS700 in JapaneseIndustrial Standard (JIS) (2008). However, SBHS steels exhibit different inelastic
behaviour from conventional steels, such as almost no yield plateau and greater
yield-to-tensile strength ratio. Hence, it is necessary to examine the applicabilityof the current compressive strength design equation of JSHB to steel plates withnew steel grades.
Regarding the compressive strength design equation of JSHB, Usami and
Fukumoto (1989), Usami (1993), and Kitada et al. (2002) show that the design
equation is un-conservative within the range 0.5<R<0.75 (intermediate range) andover-conservative in the range R>0.8 (slender range), in which R is theslenderness parameter. However, Usami and Fukumoto (1989) and Usami (1993)
consider only the normal (SM490Y) steel plates and they employed the perfectly
elstoplastic assumption for modeling the inelastic behavior of steel material.
For theses reasons, the compressive strength design equation of JSHB need to be
examined and developed for SBHS steel grades. However all the referred studies
were based on the deterministic method. The recent design specifications trend
towards the partial safety factor method (ISO 2394, 1998), in which a safety
factor separates into individual causes, such as the variability on material property
and the confidence of strength prediction method. The partial safety factor methodwith probability-based partial factors has been employed in Eurocode (CEN, 2004
and CEN, 1994) and AASHTO (AASHTO, 2007) as well. In order to determine
the safety factors and the nominal compressive strength, statistical information,such as the mean value and standard distribution of the compressive strength, isnecessary. Komatsu and Nara (1983) carried out a number of FE analyses of steel
plates with considering initial deflection based on collected measurement datafrom actual steel bridges to obtain the mean value and standard deviation ofcompressive strength. However, this study considered only residual stress�rc/�y=0.3 as a deterministic quantity, where �rc is the compressive residual
stress. Fukumoto and Itoh (1984) proposed the mean (M) and mean minus twice
standard deviation (M-2S) curves of the compressive strength on the basis of adatabase on single plate and box column compression test data. The M and M-2S
curves also show that the current JSHB design equation for steel plates undercompression is un-conservative within intermediate range and over-conservativein slender range. Fukumoto and Itoh (1984) also reported the statistical
distribution of residual stress and initial deflection. However, this study also
considered the steel plates with initial deflection W0/b > 1/150, where W0 and b
are the maximum initial deflection and plate width, respectively.
This paper intends to examine the current JSHB design equation of steel platecompressive strength for normal and SBHS steels, and to evaluate the mean andstandard deviation of compressive strength.

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2. EXAMINATION OF JSHB DESIGN EQUATION
2.1 Plate properties
Four normal steel grades SM400, SM490, SM490Y, SM570 and two bridge highperformance steel SBHS500, SBHS700 are considered in the current study. Figure
1 shows yield strengths and slenderness parameters R considered in the FE
analyses, where R is defined byRb  y 12(1   2 )
.
t E
 2k

(1)

800

800

600

600

 � � (MPa)

Yield strength (MPa)where b, t, �y, E, �, and k=4.0 stand for the plate width, thickness, yield strength,elastic modulus, poison ratio, and buckling coefficient, respectively. The aspectratio of all steel plates is assigned to equation 1.

400

200

0
0.3

SM400

SM490

SM490YSM570

SBHS500

SBHS700

0.5

0.7

0.9

R

1.1

1.3

400

200

1.5

Figure 1: Slenderness parameter andyield strength in FE analyses

00

SBHS700

SBHS500

SM570

SM490Y

SM490

SM400

0.05

0.1

0.15

0.2

� �

Figure 2: Idealized stress-strain
relations of steel grades considered incurrent study

2.2 FEM model
Nonlinear FE analysis considering both material and geometric nonlinearity is
conducted. Prandtl-Reuss equation is employed to model the steel plasticity. The
idealized uniaxial stress-strain relationships used in the numerical analyses areshown in figure 2.
Regarding the boundary condition, all four edges of a plate model are assigned as
simple supports. Figure 3 shows the distributions of residual stress and initialdeflection assumed in the FE analysis. The probabilistic distributions of residual
stress and initial deflection are based on measurement data reported in Fukumoto
and Itoh (1984).

CompressiveCompressive
strength of ordinary
bridgehighperformancesteel plates:
strength ofand
ordinaryandbridgehigh performancesteel plates:Proposal of nominal
design value
and valuecorresponding
partial safetypartial
factor safety factor
Proposal of nominal
designand corresponding1055

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The displacement control method is used to apply the compressive stress.
ABAQUS S4R shell elements are used for plate FE model with mesh size of
30x30 elements.
Simplysupported edges

a

W0

rc

y

 x   y z  W0 sin   sin   a   b 

rt
x

b

Figure 3: Idealized residual stress distribution
and sinusoidal initial deflection surface
2.3 Comparison of FE results with experimental results
1.2

1
1

0.8

 u/ y u / y

0.8
0.6
JSHB
Dorman Long
Chin
SM400
SM490YSBHS500

0.4
0.2
0
0.0

0.5

Rasmussen
HarrisonMoxham
SM490
SM570
SBHS700

R

1.0

0.6
0.4
0.2

Figure 4: Comparison of current study
results to previous test results

SM400

SM490

SM490YSM570

SBHS500

SBHS700

0
1.5

JSHB

0

0.3

0.6

R

0.9

1.2

1.5

Figure 5: Normalized compressive
strength of plate with 6 steel grades in
the case W0/b=1/400 and �rc/�y=0.23

The normalized compressive strengths obtained from the FE analyses as well as
past experimental results (Dwight and Moxham, 1969 and Rasmussen andHancock, 1992) are plotted in Fig. 4 as a function of R. In these analyses, an
initial deflection W0/b = 1/150 and a residual stress �rc/�y = 0.4 are considered asa conservative assumption. As shown in figure 4, the FEM results lay the lower
bound of experimental results, which corresponds to the conservative assumption.
2.4 Compressive strength of different steel grades
In this section, the normalized compressive strengths of different steel grades arecompared in the case of mean values of the residual stress and the initialdeflection. The mean values of normalized residual stress and initial deflection are
obtained as �rc/�y=0.23 and W0/b=1/400, respectively from the measurement data

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reported in Fukumoto and Itoh (1984). In the evaluation of the mean value of thenormalized initial deflection, the measurement data for W0/b>150 are excluded
owing to an allowable fabrication upper limit in JSHB.
As shown in figure 5, the compressive strengths of steel plates with 6 steel grades
are quite similar in the whole range of R. The largest difference occurs at R  0.7
and R  0.4, and the normalized compressive strength of SBHS700 steel plates(maximum value among 6 steel grades) is about 6% greater than that of the
SM400 steel plates (minimum value among 6 steel grades). For R > 0.4, thecompressive strength of SBHS steel plates with larger YR value is greater thanthat of normal steel plate with lower YR value.
3. COMPRESSIVE STRENGTH SCATTERNESS
3.1 Response surface
To obtain the probability distribution of the compressive strength, Monte Carlo
method is employed. However, to obtain a convergent result in the Monte Carlosimulation, it is essential to implement a large number of deterministic analyses,
and accordingly it would take long time. Hence, to overcome this problem, a
response surface of the normalized compressive strength, which is an approximate
algebraic function of the initial deflection and residual stress, is instead of thedeterministic analyses. The current study employs ten response surfaces
corresponding to the 10 considered R values.

numerical results
1.1

 u / y

1
0.9
0.8

0

0.7
0

 rc / y

0.5

0.005

W0/b 0.01

1

0.015

Figure 6: The response surface shapepresented along with FEM results for the case R = 0.8
The response surface is expressed as a simple algebraic function, u  p 00  p10 r  p 01W0  p 20 r 2  p11 rW0 
2

2

2

3

 p 02W0  p 21 r W0  p12 rW0  p30 r  p 03W0

3

(2)

CompressiveCompressive
strength of ordinary
bridgehighperformancesteel plates:
strength ofand
ordinaryandbridgehigh performancesteel plates:Proposal of nominal
design value
and valuecorresponding
partial safetypartial
factor safety factor
Proposal of nominal
designand corresponding1057

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamwhere  u   u /  y , W0  W0 / b and  r   rc /  y . The constants pij in equation 2

were determined from a set of 114 deterministic FE results for each steel gradeand R value by using the least square method.
Figure 6 shows an obtained response surface along with FE numerical results for
R=0.8. All constants of ten response surfaces are presented in Table 1. The
obtained response surfaces show good fit for numerical results in the cases R≥0.7
with the coefficient of determination (R-square) > 95%. For R<0.7, the R-squarevalues become slightly lower due to the influence of the hardening of highstrength steels (SM570, SBHS500, SBHS700).
Table 1: Constant values of 10 Response surfaces
R
value

p00

p01

p02

1.28

1.098 40.22 5442.0
1.034 15.15 1683.0
1.012 -1.72 1894.0
1.037 34.54 3169.0
1.047 65.98 8382.0
0.963 40.44 3081.0
0.850 23.31 1188.0
0.757 12.66 377.6
0.697 10.08 367.4

1.40

0.650

0.40
0.50
0.60
0.70
0.80
0.92
1.04
1.16

1058

-7.44

p03

p10

248100 0.007-90660 0.012
100500 0.087
135000 0.234
389100 0.584
112100 0.937-34700 0.788-11430 0.567-12430 0.435
229.3-8387 0.343

p11

p12

p20

-2.320-48.4 0.007-8.400-42.4 0.069
21.150 507.9 0.284
32.100 1465.0 0.568-0.520 1309.0 1.006
57.210-891.1 1.368

47.270-769.2 1.169

25.72046.8 0.856

23.330-269.2 0.617

18.580-208.5 0.462

p21

p30

2.25 0.000
6.72 0.057
11.01 0.198
9.74 0.342
15.13 0.492
35.91 0.632
29.12 0.556
20.27 0.419
15.11 0.288
11.63 0.211

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3.2 Stochastic inputs of initial imperfections
0.10

������m�l dist.
=0.23
=0.145

0.20

Weibull dist.
=0.00280
=0
m=1.37
=0.00233
=0.00156

0.09
0.08

Relative Frequancy

Relative Frequancy

0.25

0.15
0.10
0.05

0.07
0.06
0.05
0.04
0.03
0.02
0.01

0
0

0.2

0.4

 /
rc

0.6

0.8

1.0

y

Figure 7: Generated random input of
initial deflection

0
0

1

2

3

W0/b

4

5

6

7
x 10

-3

Figure 8: Generated random input of
residual stress

In the Monte Carlo simulation, the probabilistic distribution of the initialdeflection is assumed as the Weibull distribution, and the residual stress as the
Lognormal distribution as shown in figure 7 and 8 (Fukumoto and Itoh,1984). In
this figure, the generated random variables in the Monte Carlo simulation are alsoplotted as the histogram chart. The generated normalized initial defections morethan W0/b>1/150 are excluded in the simulation due to an allowable fabrication
upper limit in JSHB.
3.3 Results of Monte Carlo simulation

The probabilistic distribution of compressive strengths is obtained by applicationof the response surface and a large number of random inputs of residual stress andinitial deflection. The converged mean and standard deviation are obtained byprocessing 10000 random input couples of residual stress and initial deflection.
The histogram of compressive strength with 10000 random input couples in thecase of R=0.8 is shown in figure 9. Results of 10 convergent mean and standard
deviation of compressive strengths are presented in Table 2.
In figure 9, the mean values of normalized compressive strength with error bar
equal to two times the standard deviation are plotted along with the current JSHB
design equation, mean (M) curve and mean minus 2 standard deviation (M-2S)
curve proposed in Fukumoto and Itoh (1984).

CompressiveCompressive
strength of ordinary
bridgehighperformancesteel plates:
strength ofand
ordinaryandbridgehigh performancesteel plates:Proposal of nominal
design value
and valuecorresponding
partial safetypartial
factor safety factor
Proposal of nominal
designand corresponding1059

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Relative Frequancy

0.1
0.08
0.06
0.04
0.02
0
0.5

0.6

0.7

0.8
0.9
 /
u

1.0

1.1

1.2

y

Figure 9: Probability distribution of compressive strength for R=0.8
Table 2: Mean and standard deviation of normalized compressive strength
R
value
M
value
S
value

0.4

0.5

0.6

0.7

0.8

0.92

1.04

1.16

1.28

1.4

1.03
9
0.02
77

1.00
6
0.01
57

0.98
2
0.02
12

0.93
8
0.04
13

0.86
2
0.05
15

0.76
6
0.03
99

0.70
1
0.02
94

0.65
3
0.02
16

0.61
0.586
7
0.01 0.014
71
5

As shown in figure 9, the mean values of normalized compressive strength aresimilar to the mean curve reported in Fukumoto and Itoh (1984), which was
proposed from test results. Within 0.65≤R≤0.85, the mean values of the current
study are slightly greater than that reported in Fukumoto and Itoh (1984). One ofthe possible reasons is that the current study does not consider steel plates with
W0/b>1/150 and the influence of initial deflection on compressive strength ismore significant within the mentioned range of R than other ranges. Also seen in
Fig.9, the M-2S curve proposed in Fukumoto and Itoh (1984) is too conservative
if compared to corresponding results of the current study.
A comparison of standard deviation of compressive strengths obtained in thecurrent study and previous study Fukumoto and Itoh (1984) is presented in Fig.10.
Within the practical range 0.6<R<1.2, the standard deviations of the current study
exhibit about half of reported values in Fukumoto and Itoh (1984). As seen in the
figure, the standard deviations obtained by the current study have a clearer
tendency, and attained to the maximum value at R0.8. Within the range
0.7<R<0.9, the ultimate state of compressive plates is elastoplastic buckling, andaccordingly the compressive strength is significantly influenced by both residual
stress and initial deflection. For R>0.9, the standard deviation decreases, and theelastic buckling becomes dominant. The residual stress has almost no effect on thecompressive strength. For R < 0.7, the compressive strength tends to attain theyield strength and is mainly influenced by initial deflection. In particular for
R<0.5, the hardening behavior of high strength steel (SM570, SBHS500 and
SBHS700) starts to have a significant effect on the compressive strength.

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0.20

Standard deviation1

 u/ y

0.8
JSHB

0.6

M ean results

0.4

Fukumoto M curve

0.2

Current study

0.15

From Fukumoto Exp.
0.10
0.05

Fukumoto M -2S curve

0.00

0
0.0

0.2

0.4

0.6

0.8

R

1.0

1.2

0.3

1.4

0.6

0.9

R

1.2

1.5

Figure 11: Comparison of standard
deviation values obtained in current
study and reported in Fukumoto and
Itoh (1984)

Figure 10: Comparison between current
study, JSHB, 2002, and Fukumoto and
Itoh (1984) results

4. PROPOSAL OF SAFETY FACTOR

The reliability index is used to specify a safety margin  T 

1



fN

(3)

where  and  are the mean and standard deviation of normalized compressive
strength, respectively; T stands for the target reliability index;  and f N are thesafety factor and the corresponding nominal strength, see figure 12 for the
probability density function and the approximated normal distribution at R=0.8.
Table 3. Partial safety factors in the range of 0.4≤R≤1.4
R
fN =�
�(5%)
�(3%)
��1%
)

0.4
1.03
9
1.05
1.05

0.5
1.00
6
1.03
1.03

0.6
0.98
2
1.04
1.04

0.7
0.93
8
1.08
1.09

0.8
0.86
2
1.11
1.13

0.92
0.76
6
1.09
1.11

1.04
0.70
1
1.07
1.09

1.16
0.65
3
1.06
1.07

1.28
0.61
7
1.05
1.06

1.4
0.58
6
1.04
1.05

1.07

1.04

1.05

1.11

1.16

1.14

1.11

1.08

1.07

1.06

Assuming that the probability density of compressive strength is described by anormal distribution, and assigning non-exceedance probabilities of compressive
strength to 5.0, 3.0, and 1.0%, then the corresponding target reliability incises
become 1.64, 1.88, and 2.33. Furthermore, setting the nominal compressive
strength equal to the mean of compressive strengths as an example, the partial
safety factor can be obtained as shown in Table 3.

CompressiveCompressive
strength of ordinary
bridgehighperformancesteel plates:
strength ofand
ordinaryandbridgehigh performancesteel plates:Proposal of nominal
design value
and valuecorresponding
partial safetypartial
factor safety factor
Proposal of nominal
designand corresponding1061

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Vietnam

R=0.8

0.05

βT 

0.04



0.8

  βT 

0.035
0.03
0.025
0.02
0.015

AASHTO nominal
strength curve1 u/ yRelative Frequancy

0.045

Non-exceedance
Exceedance
probability
probability

0.01

0.6
0.4

Nominal strength

0.2

3% fractile

5% fractile

0.005
0
0.5

0.6

0.7

0.8

 /
cr

0.9

1.0

1.1

y

Figure 12: Explanation of equation 3

AASHTO design
strength curve

1% fractile

0
0.0

0.2

0.4

0.6

R

0.8

1.0

1.2

1.4

Figure 13: proposal compressive
strengths

As represented above, the current study only considers the scatterness of initial
imperfections and without considering scatterness of steel material yield strength,
the Eq.4, the nominal compressive strength equation for simply supported steel
plates is proposed based on compressive strength mean values. The comparison
to AASHTO nominal curve is presented in Fig.13 u 
y 

10.0775 0.630 0.223
0.399  R  R 2  R 3

R  0.55(4)
R  0.55

The general curvature tendency of proposal nominal compressive equation is lesssteep than that of AASHTO. This behavior represents the difference of the steel
plate compressive strength which is obtained by considering inelastic material
behavior and nonlinear geometrical analysis and the ones which results from theelastic local buckling theory.

5. CONCLUSIONS

The mean values obtained in the current study are similar to those proposed in
Fukumoto and Itoh (1984), but slightly greater within the range 0.7<R<0.9. The
standard deviation of compressive strength obtained in this study is about half ofvalues reported in Fukumoto and Itoh (1984) within a range of 0.6<R<1.2. The
M-2S curve proposed in Fukumoto and Itoh (1984) is too conservative if
compared to corresponding values obtained in the current study. The results of M2S of the current study show that the current load-carrying-capacity JSHB design
equation of steel plates is un-conservative within the range 0.5 < R < 0.8 andover-conservative for R > 0.85.
Within the range of slenderness parameter 0.4≤R≤1.4, the normalized
compressive strengths of normal steel and SBHS steel are similar for the same1062

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levels of R and initial imperfections. However, compressive strength of steel
plates with SBHS grades with greater YR is slightly greater than that of normal
steel grades.
With assumption of normal distribution function applying to probabilistic
distribution of steel plate compressive strength and the compressive strength meanvalues considered as nominal strengths, the partial safety factors obtained areequal to 1.11, 1.13 and 1.16 corresponding to 5%, 3% and 1% fractile,
respectively.
REFERENCES

American Association of State Highway and Transportation Officials, 2007.
“AASHTO LRFD bridge design specification” – Fourth edition.
CEN, Eurocode3, 2004. “Design of Steel Structures”, Part 1-5, plated structuralelements.
CEN, Eurocode4, 1984. “Design of Composite Steel and Concrete Structures”,
Part 2, General rules and rules for bridges.
Dwight, J., B., Moxham K. E., 1969. “Welded steel plates in compression”, The
Structural Engineer, Vol. 47, No. 2, pp. 49-66.
Fukumoto, Y., and Itoh, Y., 1984. “Basic compressive strength of steel plates fromtest data”, Proc. of JSCE No.334/I-1,
Fukumoto, Y., 1996. “New constructional steels and structural stability”,
Engineering structures, Vol.18, pp. 786-791.
International Standard ISO 2394, 1998. “General principles on reliability forstructures”, Third edition,
Japan Road Association, 2002. “Specifications for Highway Bridges” – part II.
Steel Bridges.
Japan Road Association, 1980. “Specifications for Highway Bridges” – part II.
Steel Bridges,
Japanese Industrial Standard, 2008. “JIS G 3140, Higher yield strength steel plates
for bridges”.
Kitada, T., Yamaguchi, T., Matsumura, M., Okada, J., Ono, K., and Ochi, N., 2002.
“New technology of steel bridge in Japan”, Journal of Constructional Steel
Research, Vol.58, pp. 21-70.
Komatsu S, and Nara, S., 1983. “Statistical study on steel plate members”,
Journal of Structural Engineering, ASCE, Vol. 109, No. 4.
Rasmussen, K., J., R., and Hancock, J., G., 1992. “Plate slenderness limits for highstrength steel sections”, J. Construct. Steel Research. Vol.23, pp. 73-96.
Usami, T., and Fukumoto, Y., 1989. “Deformation analysis of locally buckledsteel compression members”, Journal of Constructional Steel Research, Vol.13,
pp. 111-135.
Usami, T., 1993. “Effective width of locally buckled plates in compression andbending”, Journal of Structural Engineering, ASCE, Vol. 119, No. 5, pp. 13581373.

CompressiveCompressive
strength of ordinary
bridgehighperformancesteel plates:
strength ofand
ordinaryandbridgehigh performancesteel plates:Proposal of nominal
design value
and valuecorresponding
partial safetypartial
factor safety factor
Proposal of nominal
designand corresponding1063

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New Technologies for Urban Safety of Mega Cities in Asia

Hybrid technology of up-flow anaerobic filter
and membrane bio-reactor for recovery
energy from rich organic waste stream
Thu Hang DUONG, Duc Ha TRAN, Hoai Son TRAN,
Thi Viet Nga TRAN, Bich Ngoc HOANG, Thuy Lien NGUYEN
Lecturer and Researcher, Institute of Environmental Science and Engineering,
National University of Civil Engineering, Vietnam
hatd@nuce.edu.vn

ABSTRACTBrewery wastewater is typically one of rich organic waste streams, which
concentrations of main pollutants are in the range of 970-3050 mg COD/L, 6802150 mg BOD5/L, 300-500 mg TSS/L and 80-90 mg TN/L. Experimental researchon biological process treating brewery wastewater in Sai Gon-Hanoi Brewery
Plant was set up with an up-flow anaerobic filter (UAF) followed by membranebio-reactor (MBR). The UAF had a stable performance at room temperature(~200C) after 20 operating day, and a methane yield of 0.25 NL/g CODadded was
obtained at hydraulic loading rate of 1.5 L/L.day and organic loading rate of 2-4
g COD/L.day. The highest removal efficiency of pollutants was achieved at aconcentration of 7.5-8.5 g MLSS/L in the MBR, and MBR process stability wasattained at flux and organic loading rate were below 9 L/m2.h and 3 g COD/L.day,correspondingly. The treated effluent of the system was complies with theVietnamese standard QCVN 40:2011/BTNMT (column A), which could be reused
for numerous purposes in brewery plants. Additionally, sludge discharged from
UAF and MBR was anaerobically stabilized at mesophilic condition (~35-370C),
recovering approximately 150 NL of methane per 1 g CODremoved. The remarkable
results of research revealed that this new hybrid technology of UAF and MBR
was a sustainably saving energy solution for rich organic wastewater treatment.
Keywords: rich organic waste stream, brewery wastewater, up-flow anaerobic
filter, membrane bio-reactor, recovery energy

1. INTRODUCTION
Wastewater discharged from food industries are generally characterized with richorganic and nutrient contents, e.g. COD ≥ 2 000 mg/L, TN ~ 100 mg/L, and tend
to bring serious water environment contamination if discharged without proper
treatment (Tran, 2002; Oreopoulou and Russ, 2007). Like any other food industry,
the brewing industry is subject to extensive government regulations including
numerous environmental protection laws. It is estimated that for the production of
1 L of beer, 3-10 L of waste effluent is generated, mostly from the brewing,rinsing and cooling processes (Brito et al., 2007; Oreopoulou and Russ, 2007).

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The conventional treatment of this kind of high strength wastewater is traditional
anaerobic/aerobic activated sludge process which is often wasteful of resource andproblematic in performance for most breweries. Besides, there are few reports on
the integration of anaerobic and aerobic process for cost-effectively and stably
treating of the high strength wastewater.
This research proposed the application of hybrid technology of up-flow anaerobic
filter (UAF) and membrane bioreactor (MBR) for treating of rich organic waste
streams. Several key points of this hybrid technology include a positive energybalance, reduced sludge production, a high biomass concentration in reactor, avery long sludge retention time resulting in the complete retention of slowgrowing micro-organisms such as nitrifying bacteria, and significant low spacerequirements (Chae et al., 2007; Hai et al., 2011). In terms of energy point ofview, methane produced from UAF and anaerobic processes which can be directly
utilized in a boiler is firmly the preferred solution in breweries. In the context ofdecreasing fossil fuel reserves, energy recovery through generation of methanefrom rich organic waste makes a brewery more independent from external fuelsupply and contributes to a more sustainable brewing process. Furthermore,
membrane use can produce high quality effluent free of bacteria, offering thepossibility of water reclamation. The objectives of this study are to set up a
brewery wastewater treatment model at laboratory scale using up-flow anaerobic
filter for pretreatment combined with membrane bio-reactor, to determine
operating data and to access the efficiency and performance of wastewater
treatment system. Furthermore, the study aims to examine the stabilization ofsludge generated in the system and methane yield producing from excess sludge
for energy recovery.

2. MATERIALS AND METHOD
2.1. Substrate and inoculum
The studied materials were wastewater and sludge provided by Sai Gon-Hanoi
Brewery Plant (Vietnam). Wastewater was collected from the regulating tank,after screening, of Wastewater treatment plant (WWTP) in Sai Gon-Hanoi
Brewery Plant. The inoculum sludge for the anaerobic and aerobic reactors at thelaboratory was the sludge of up-flow anaerobic sludge blanket (UASB) and of
sequencing batch reactors (SBR).
2.2. Experimental set up and operation
The experiment strategy was maximizing the resource recovery (methane as green
energy and reuse treated wastewater) from the rich organic wastewater and fromgenerated sludge of the wastewater system itself, characterized by two following
experiments at the laboratory scale.
Experiment 1: Rich organic wastewater treatment experiment
The anaerobic filter had a dimension of DxH of 20x50 cm, with the working
volume of 10 L, operating in up-flow mode (UAF) with 20 cm of Kaldnes
moving-bed. The aerobic membrane bioreactor had a dimension BxLxH of1066

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8x25x25 cm, the working volume of 6 L, equipped with the oxygen supply tomaintain DO higher than 2 mg/L. The membrane module was a plate type of
Kubota (type 203), made by PVDF (polyvinylidene fluoride), with the pore size of
0.4µm (MF) and area of 0.1m2 per plate, submerged in the reactor. Scheme of theexperimental system and the picture of the system are described in Figure 1.

(a)(b)
Figure 1: Scheme (a) and picture (b) of the wastewater treatment experiment(1) Influent tank, (2) UAF, (3) MBR, (4) Effluent tank, (5) Membrane module, (6)Inlet pump, (7) Aerator, (8) Water sampling, (9) Kaldnes moving-bed, (10) Outlet
pump, (11) Sludge sampling
At start-up, 5L anaerobic sludge from UASB (TS: 27.5 ± 2.4 g/L; VS: 13.6 ± 3.6g/L) and 6 L activated sludge from SBR (TS: 9.3 g/L; VS: 7.5 g/L) of the WWTP
were inoculated in the UAF and MBR, correspondingly, of the experimental
system. Wastewater in the influent tank was pumped into the UAF at the bottom.
The water level covered the filter media by 10 cm owing to a hole-bored-plastic
plate to guarantee an even flow regime. The over flow came into MBR then, thetreated water was sucked through submerged membrane to effluent tank. The gas
produced from the UAF was determined by the communicating vessel. Sludge
generated from UAF and MBR was periodically let out according to the sludge
retention time of each reactor for the sludge stabilization test. The operation
regime of UAF and MBR are shown in Table 1 and 2.
Table 1: Operation strategy of UAF
Operation data
Unit
Phase 1
Phase 2Phase 3
COD concentration of inlet
1500mg/L
1050-2650 1283-2683
UAF
2868
Hydraulic loading rate (Lq) L/L.day
1.06
1.44
2.32
Hydraulic retention time
H
23
17
10
(HRT)
Operation duration (t)
Day
25
30
30
The operation strategy was characterized by increasing of organic and hydraulicloading rate (OLR and HRT) to maximizing the pollutant treatment efficiency andmethane production from the brewery wastewater of the system and investigating
the optimum operation data for stable performance of each reactor.
Table 2: Operation strategy of MBR
Phase
Phase
Operation data
Unit
Phase 3 Phase 41
2
COD concentration of inlet
4533338001103mg/L
MBR
1053
1090
1108
1268
Hybridoftechnology
of up-flowfilter
anaerobic
filter andbio-reactor
membrane bio-reactor for recovery
Hybrid technology
up-flow anaerobic
and membraneenergyfromrichorganic
waste
streamfor recovery energy from rich organic waste stream1067

October
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Hanoi,Hanoi,
Vietnam0ctober
VietnamHydraulic loading rate (Lq) L/L.day
2.04
1.32
2.76
3.72
2
Flux (F)L/m .h5.1
3
6.9-9.3
9.3
Hydraulic retention time
h
12
18
9
6
(HRT)
Operation duration (t)
day
25
30
20
10
The water samples were collected at 3 points: the inlet of UAF, the outlet of UAF
and the outlet of MBR (at valve 8, Figure 1). The analytical parameters including
temperature (t0C) and pH determined once a day; chemical oxygen demand(COD), total suspended solids (TSS), ammonium (NH4+-N), total nitrogen (TN):
2-3 times per week; biological oxygen demand (BOD5), turbidity, color and total
phosphorus (TP): 2-3 times per month. At MBR, concentration of disolved
oxygen (DO) and mixed liqour suspended solid (MLSS) were determined once aday.
Experiment 2: Anaerobic fermentation of excess sludge
Sludge generated from UAF and MBR of the wastewater treatment system weredigested in anaerobic condition at the batch mode for investigating the sludge
stabilization and methane production. The microbial seeding, harvested from the
UASB sludge of the WWTP, was added at the start to obtain the F/M ratio equal
to 0.5. The reactors with the working volume of 500 mL, were continuously
mixing-equipped with the magnet stir system (as Continuous flow stirred-tankreactor: CSTR), incubated in the water bath at mesophilic condition (35-370C).
One reactor was set-up with the UASB sludge, incubated at the same condition forcontrol the experiment. Methane produced from each reactor was collected
through silicon tube, removed CO2 and measured by the gas columns. Figure 2
demonstrates the scheme and picture of the experiment of sludge fermentation.
BiogasIncubator (T = 52°C)

Influent
Feed

Effluent(V=1L)
Anaerobic reactor
Biogas collection(a)(b)
Figure 2: Scheme (a) and picture (b) of the sludge fermentation experiment
In the sludge test, three sludge samples were collected from each reactor: at the
beginning- after the addition of sludge substrate (day 0), after 5 operation days
(day 5) and at the end of experiment-when no gas produced for 3 continuous days.
The analytical parameters including total solids (TS), volatile solids (VS), pH,
total COD and soluble COD, NH4+-N, TP were determined in the sludge samples.
2.3. Analytical methods
Gas production was measured by liquid displacement. The pH values were
measured with a WM-22EP pH meter (Toaodk, Japan). The DO and MLSS were
measured with HQ30d (Hach) and IM-50P (Motto, Japan), correspondingly. The

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alkalinity, turbidity, color, total COD (CODtot) and soluble COD (CODsol), BOD5,
TS, TSS, VS, NH4+-N, TN and TP were determined according to the the Standard
Methods (APHA-AWWA-WPCF, 1999).

3. RESULTS AND DISCUSSION
3.1. Composition and characteristics of brewery wastewater
Table 3 shows the main characteristics of the substrate brewery wastewater usedin the experiments.
Table 3: The main characteristics of brewery wastewater
Parameters
Unit
Brewery wastewater
Average
No.
Range of
valu
value
e
1 pH
4-8
6.1
Biological oxygen demand,2
mg O2/l
680-2150
1650
BOD5Chemical oxygen demand,3
mg O2/l
970-3050
1940
COD
4 Total suspended solid, TSS
mg/l
300-500430
5 Turbidity
NTU
400-600490
6 Color
Pt-Co
1700-2250
1955
7 Total phosphorus, TP
mg/l
0,1-107
8 Total nitrogen, TN
mg N/l80-90
87.4
mg NH49 ammonium, NH4+-N
30-40
32.3
N/l
Brewery wastewater typically has a high COD content, mostly easily
biodegradable from all the organic components (sugar, soluble starch, ethanol,
volatile fatty acids, etc.) leading to COD/BOD5 ratio of 1.1to 1.5. The effluent
solids consist of spent grains and kieselguhr waste yeast. TN concentration in thetested wastewater were higher than typical brewery effluent composition (25-80mg/L) but TP was lower (10-50 mg/L) (Brito et al., 2007; Oreopoulou and Russ,2007). Nitrogen and phosphorous levels are mainly depending on the handling of
raw material and the amount of spent yeast present in the effluent. Low
phosphorus levels can also result from the bio-chemicals used in the CIP unit. The
ratio of COD:N: P in the wastewater was 1940 : 87 : 7 ~ 277 : 12 : 1. In theanaerobic condition, the required nitrogen content for anaerobic microorganism inrich organic substrates should be approximately COD:N ≈ 350:5 and phosphorus
demand account for 1/5 to 1/7 of nitrogen. Compared to the optimum balanced
nutrient ratio for anaerobic microorganism, the brewery wastewater had likely
sufficient carbon and phosphorus source, but nitrogen in excess.
3.2. The UAF’s performance and methane yieldAs wastewater up-flows through the filter, particles were trapped and organic
matter was anaerobically degraded by the biomass that was attached to the surface
Hybridoftechnology
of up-flowfilter
anaerobic
filter andbio-reactor
membrane bio-reactor for recovery
Hybrid technology
up-flow anaerobic
and membraneenergyfromrichorganic
waste
streamfor recovery energy from rich organic waste stream1069

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Vietnam

100
90
80
70
60
50
40
30
20
10
0

12,0

6,0
5,0
4,0
3,0
2,0
1,0
0,0
0

10

20

30

40

50

Time (days)

60

70

80

90

Metan yield (NL/day)

7,0
OLR (g COD/L.day)

COD removal efficiency (%)

of filter material. Figure 3 shows the COD removal efficiency and the methane
yield in UAF during the operation time.
10,0
8,0
6,0
4,0
2,0
0,0
0

10

20

30

40 50 60
Time (days)

70

80

90

Figure 3a: Change of OLR and COD
Figure 3b: Methane yield in UAF
removal efficiency in UAF (▲:OLR; ■:COD removal efficiency)
The microbial seeding in this experiment had VSS concentration was 13.6 g/L,
accordance to Elmitwalli and Chernicharo for anaerobic digestion of domestic
wastewater and rich organic streams (at least 10 g VSS/L) (Elmitwalli et al.,
2001; Chernicharo, 2007). It had been observed that the start-up period needed for
microorganism to immobilize on the moving-bed of UAF was 20 days. At the endof phase 1, COD removal efficiency reached 80%, which was agreed with thereview of Chernicharo and Legginga (Lettinga et al., 2001; Chernicharo, 2007)
for UASB and UAF (75-85%) as well as the highest value (82%) in UAF fortreating brewery wastewater in the study of Yu and Gu (Yu and Gu, 1996). The
result of this research pointed out that, with the appropriate microbial seeding already adapted to brewery wastewater, the start-up to aerobic microorganism getused to and fix on the surface of filter material of UAF remarkably decreased
compared to the typical start-up duration for establishing sludge blanket in UASB
of 2 to 8 months (Yu and Gu, 1996; Chong et al., 2012).
Phase 2 and 3 started with the increasing of the OLR and HLR to 1.5-3 folds, theCOD removal efficiency suddenly went down to below 27%, COD concentrationof the effluent of UAF higher than 1 g/L. However, after 7 day, the efficiency
gradually increased to approximately 70% and stabilized till the end of phase 2
although there was another increase of OLR to nearly 6 g COD/L.day, equivalent
to the high range of loading rate of UAF (5 g COD/L.day) (Lettinga et al., 2001;
Chernicharo, 2007) but keep the HLR constant. It was found that the increasing of
HLR had more severe influence on the organic matter transformation of
microorganism than the increasing of OLR. It could be due to the effect ofwashing-out part of microorganism when high flow was applied, leading to thegrowing of COD in the effluent. However, when the microorganism stably
attached on the filter, the ‘shock’ effect in the later phase became lessen. Besides,
the COD removal efficiency in UAF could not achieve above 60-65% at the endof phase 3. In other words, the loading rate threshold of UAF could not surpass
the value of 6 g COD/L.day or 2 L/L.day.
Figure 3 (b) showed that the result of methane yield increased in each phase, but
dropped at the beginning when there was a change of loading rate. This was inaccordance with the change of COD removal efficiency. This progress could be
explained that the anaerobic fermentation was constituted by a chain of activities
of anaerobic microorganisms and among the anaerobic microorganisms, the1070

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hydrolysis, acidogens and even acetogens microorganism likely promptly adapted
to the change of organic concentration of the input stream. However the growth of
methanogens was remarkably slower, about 25 times less than the growth ofacetogens (Chernicharo, 2007). Then, the removal rate of hydrogen andtransformation of VFAs by methanogens could not keep pace with theaccumulation of VAFs, leading to the depression of pH value and intensively
inhibition of methanogens in the system. However, once the VFAs reduced by theoutlet and gas off, the methanogens could be strengthen upon the filter matter,hence the methane yield gradually increased in each phase. The methane yieldrecorded at the end of phase 1, 2 and 3 correspondingly, was 5.3, 9.0 and 10.2
NL/day, equivalent to 0.21, 0.25 and 0.16 NL/g CODadded. Compared to theorganic loading rate and the COD removal efficiency, the efficiency of methane
production in UAF in 3 phases was 65%, 74% and 70%.
3.3. The MBR performance and COD removal efficiency

0

10

20

30

40 50 60
Time (days)

70

80

90

OLR (g COD/L.ngày)

5,0
4,5
4,0
3,5
3,0
2,5
2,0
1,5
1,0
0,5
0,0

COD removal efficiency (%)

100
90
80
70
60
50
40
30
20
10
0

COD Concentration (mg/L)

The COD removal efficiency and the concentration of COD in the wastewater inout of UAF and MBR were demonstrated in Figure 4. Figure 5 showed the change
of MLSS, sludge loading rate and ratio of F/M in the MBR.
3000
2500
2000
1500
1000
500
0
0

Figure 4a: Change of OLR and COD
removal efficiency in MBR(▲:OLR; ■: COD removal efficiency)

10

20

30

40 50 60
Time (days)

70

80

90

Figure 4b: Change of concentration of
COD in wastewater in-out of the UAF
and MBR (■:COD of UAF inlet; ▲:COD of UAF outlet; ●: COD of MBR
outlet)

The result of this experiment shown that, right from the start, the COD removal
efficiency achieved above 94% although the high COD concentration of the
inflow. The MLSS remained stable at 12.5-14.0 g/L during phase 1, but depressed
nearly 30% in phase 2, leading to a decrease of COD removal. It could be due tothe short of organic content in the inflow of MBR resulted in the oxygenation of
intracellular of activated sludge in phase 2.

Figure 5a: MLSS in MBR

Figure 5b: Sludge loading rate and ratio of
F/M in MBR (●:SLR; ▲: F/M)

Hybridoftechnology
of up-flowfilter
anaerobic
filter andbio-reactor
membrane bio-reactor for recovery
Hybrid technology
up-flow anaerobic
and membraneenergyfromrichorganic
waste
streamfor recovery energy from rich organic waste stream1071

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnam

In order to test the threshold and performance of MBR, phase 3 and 4 started withthe continuous increase of OLR and HLR in the reactor (3-4.5 g COD/L.day and2-4 L/L.day). At phase 3, the sludge loading rate was 0.4 g COD/g sludge.day andratio of F/M stable at 0.1 with the hydraulic retention time of 9 hour, theefficiency of COD removal was 95%, and the COD concentration in effluent
below 75 mg/L (column 1, QCVN 40:2011/BTNMT). Compared to the result of
Wang, Chae and Churchouse’s research, this study shown considerably
achievement in MBR performance for high-strength wastewater (Churchouse,
1998; Wang et al., 2005; Chae et al., 2007). Once the sludge loading rate reached
at 0.5 g COD/g sludge.day, the effluent quality declined, COD removal efficiency
was below 90% and COD concentration in effluent was higher than 75 mg/L.
Similarly, in the research of Chang and Churchouse, the COD removal efficiency
reached at 85% at the organic loading rate of 2.7 g COD/L.day (Churchouse,
1998; Chang et al., 2007). The result of MBR performance demonstrated the great
advantages of MBR system compared to the traditional activated sludge,
regarding the adaptation to change of inflow, pollutant concentration and OLR of
the influent, especially in the food industries. The optimum range of operation
data for the best performance of MBR system in treating rich organic stream wasrecommended phase 3.
3.4. Assess the characteristics of effluent of hybrid technology UAF-MBR
The change of pH and ammonium concentration in the wastewater in-out of UAFMBR was recorded in Figure 6 during operation time. The pH value of
wastewater out of UAF gradually went up from approximately 5 to 7 in the first
10 days and remained constant around 7.02 ± 0.29 (within the optimum range formethanogens of 6.7-7.4), which proved the development of anaerobic
microorganism and methane production in the UAF. Concurrently, the anaerobic
fermentation of rich organic and nutrient matter in brewery wastewater led to theincreasing of ammonium, from 32.3 ± 14.7 mg NH4+-N /L of the brewery
wastewater to 52.5 ± 23.8 mg NH4+-N /L in the effluent of UAF. The change ofthese value proved that the hydrolysis had been strongly active at the very first
beginning hence; the rate of hydrolysis was not the limiting factor of the wholeanaerobic process in UAF treating easily biodegradable wastewaterpH

NH4+-N Concentration(mg/L)

10
9
8
7
6
5
4
3
2
1
0
0

10

20

30

40 50 60
Time (days)

70

80

90

100
90
80
70
60
50
40
30
20
10
0
0

10

20

30

40 50 60
Time (days)

70

80

90

(a)
(b)
+
Figure 6: Change of pH value (a) and NH4 -N concentration (b) in the wastewaterin-out of UAF-MBR (■: value of UAF inlet; ▲: value of UAF outlet; ●: value of
MBR outlet)

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The concentration of ammonium in the wastewater drastically dropped in MBR
due to the nitrification process and fluctuated around 4.0 ± 2.0, keep below 10
mg/L (column A, QCVN 40:2011/BTNMT) throughout the operation time. The
NH4+-N removal effiency of MBR and of whole system (UAF-MBR) was 91.2±
7.5% and 83.6 ± 16.0%, correspondingly.
3.5. Sludge stabilization and methane production

Methane volume accumulation (NL)

The accumulation of volume of methane produced in three anaerobic reactors(control, UAF’s sludge and MBR’s sludge was shown in Figure 7. In term ofenergy recovery, the methane yield of 3 kinds of sludge: UASB, UAF and MBR
were 174, 149 and 153 NL/g CODadded, equivalent to the methane production
efficiency of those 50, 43 and 44%. It pointed out that, the settled sludge down in
UAF consisted of mostly hard-biodegradable particulate (the easily part had been
already degraded better in UAF than in UASB); hence the methane yield
generated from anaerobic digestion of UAF was lower than in UASB sludge.
800

Figure 7: Accumulated volume of
methane producing in anaerobic
reactors in experiment 2 (●:reactor 1 of UASB sludge; ■:reactor 2 of UAF sludge; ▲:reactor 3 of MBR sludge).

700
600
500
400
300
200
100
0
0

5

10

15

Time (days)

The VS and COD removal or the stabilization of sludge efficiency of all reactors
achieved about 61-66%. This result was agreed with the other research on
anaerobic digestion of sewage sludge, the organic matter removal achieved only
40-70% and the methane gas production were 35-60% if sludge had not been pretreated (Wen et al., 1999; Carballa et al., 2005).
4. CONCLUSION
In this paper, a laboratory scale of the UAF-MBR system was tested for treating
brewery wastewater and the following results were obtained:
i. The UAF had a stable performance at room temperature (~200C) after 20
operating days, the COD removal efficiency of above 70% and a methane yieldof 0.25 NL/g CODadded were obtained at hydraulic loading rate of 1.5 L/(L.day)and organic loading rate of 2-4 g COD/L.day.
ii. The MBR did not required the start-up period if obtained a sufficient microbial
seeding. The highest removal efficiency of pollutants of above 94% wasachieved at a concentration of 7.5-8.5 g MLSS/L. The MBR process stability
was attained at flux and organic loading rate were below 9 L/(m2.h) and 3 g
COD/(L.day), correspondingly, the sludge loading rate of 0.3-0.4 g COD/L.day
and ratio of F/M at around 0.1.
iii. The removal efficiencies of COD, BOD5 và TSS in the hybrid process UAFMBR were above 97%, 95 and 98%, correspondingly; the quality of theHybridoftechnology
of up-flowfilter
anaerobic
filter andbio-reactor
membrane bio-reactor for recovery
Hybrid technology
up-flow anaerobic
and membraneenergyfromrichorganic
waste
streamfor recovery energy from rich organic waste stream1073

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnameffluent stable and conform the column A, QCVN 40:2011/BTNMT, which
could be reuse for numerous purposes in brewing processes.
iv. Anaerobic digestion of sludge discharged from UAF and MBR at mesophilic
condition (~35-370C) recovered approximately 150 NL of methane per 1 g
CODremoved. The VS and COD removal or the stabilization of sludge efficiencyof all reactors achieved about 61-66%.
As an effort for sustainable development in food industries and wastewater
treatment, the remarkable results of this research highlighted that this hybrid
technology of UAF and MBR is an effective and energy-saving solution fortreating rich organic waste streams.

ACKNOWLEDGEMENT
The research is within in the framework of the scientific research “Study on
design and manufacture of small-scale wastewater treatment system applying
membrane bioreactor technology”, part of Project ‘Development of Vietnamese
environmental industry in 2015, up to 2025, sponsored by Ministry of Industry
and Trade, Vietnam.

REFERENCE
APHA-AWWA-WPCF (1999). Standard Methods for the examination of water
and wastewater. L. S. Clesceri and Greenberg. Washington, DC 20005, American
Public Health Association.
Brito, A. G., J. Peixoto, J. M. Oliveira, J. A. Oliveira, C. Costa, R. Nogueira and
A. Rodrigues (2007). Brewery and winery wastewater treatment: some focal
points of design and operation. Reykjavik, Iceland, Springer.
Carballa, M., F. Omil, A. C. Alder and J. M. Lema (2005). Comparison between
the conventional anaerobic digestion of sewage sludge and its combination with achemical or thermal pre-treatment concerning the removal of pharmaceuticals
and personal care products. 4th International Symposium on Anaerobic Digestionof Solid Waste, Copenhagen, Denmark.
Chae, S. R., S. T. Kang, S. M. Lee, E. S. Lee, S. E. Oh, Y. Watanabe and H. S.
Shin (2007). "High reuse potential of effluent from an innovative verticalsubmerged membrane bioreactor treating municipal wastewater." Desalination
202(1-3): 83-89.
Chang, T. C., S. J. You and S. H. Chuang (2007). "Evaluation for the reclamation
potential of high-tech industrial wastewater effluent treated with different
membrane processes." Environmental Engineering Science 24(6): 762-768.
Chernicharo, C. A. d. L. (2007). Anaerobic Reactors. Biological Wastewater
Treatment Series. London, UK, IWA Publishing. 4.
Chong, S., T. K. Sen, A. Kayaalp and H. M. Ang (2012). "The performanceenhancements of Upflow Anaerobic Sludge Blanket (UASB) reactors for domestic
sludge treatment - A State of the Art Review." Water Research.
Churchouse, S. (1998). "Membrane bioreactors for wastewater treatment operating experiences with the Kubota submerged membrane activated sludge
process." Membrane Technology 83: 5-9.

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Citiesin AsiaCities in Asia

ICUS Report 73

Elmitwalli, T. A., J. Soellner, A. De Keizer, H. Bruning, G. Zeeman and G.
Lettinga (2001). "Biodegradability and change of physical characteristics ofparticles during anaerobic digestion of domestic sewage." Water Research 35(5):1311-1317.
Hai, F. I., K. Yamamoto and W. Editor-in-Chief:Â Â Peter (2011). 4.16 Membrane Biological Reactors. Treatise on Water Science. Oxford, Elsevier:571-613.
Lettinga, G., S. Rebac and G. Zeeman (2001). "Challenge of psychrophilicanaerobic wastewater treatment. Trends in Biotechnology." Biotechnology
Advances 19(9): 363-370.
Oreopoulou, V. and W. Russ, Eds. (2007). Utilization of By-Products andTreatment of Waste in the Food Industry. Brewery and winery wastewater
treatment: some focal points of design and operation. Reykjavik, Iceland, Springer.
Tran, D. H. (2002). Study on Wastewater treatment for brewery factories inVietnam, Ministry of Education and Tranining. 2/2002.
Wang, Y., X. Huang and Q. Yuan (2005). "Nitrogen and carbon removals fromfood processing wastewater by an anoxic/aerobic membrane bioreactor." Process
Biochemistry 40(5): 1733-1739.
Wen, C., X. Huang and Y. Qian (1999). "Domestic wastewater treatment using ananaerobic bioreactor coupled with membrane filtration." Process Biochemistry35(3â€“4): 335-340.
Yu, H. and G. Gu (1996). "Biomethanation of brewery wastewater using ananaerobic upflow blanket filter." Clearner Production 4(3-4): 219-223.

Hybridoftechnology
of up-flowfilter
anaerobic
filter andbio-reactor
membrane bio-reactor for recovery
Hybrid technology
up-flow anaerobic
and membraneenergyfromrichorganic
waste
streamfor recovery energy from rich organic waste stream1075

October 2013, Hanoi, Vietnam

1076

New Technologies for Urban Safety of Mega Cities in Asia

The risk assessment by the AHP method andcharacteristics of the landslides
in Sa Pa ,Lao Cai province northern Vietnam

Dr. Takami KANNO1, Dr. Hiroyuki YOSHIMATSU1
Mse. Do Ngoc Trung2, Sr. Eng. Nguyen Quoc Hung2
1
Kawasaki Geological Engineering Co.,Ltd, Japan &2Vietnam Japan Engineering Consultants Co.,Ltd, Vietnam

ABSTRACTSa Pa district in Lao Cai province is located at the foot of the highest peak Fansipan in Indocina,that is one of leading tourist destination in Vietnam. The slope disasters such as landslides andcollapse has occurring frequently along the Highway No 4 between Sa Pa and Lao Cai, and thatwas forced to closed to traffic frequently.
In this project, we conducted field survey and topographical analysis based on satellite images
for investigating features such as collapse and landslides along the Highway No 4 between Sa Pa
and Lao Cai. Based on the results of these investigations, we have created a hazard map, andcarried out risk assessment by the AHP which is one of operations research method. Furthermore,
we carried out detailed investigation of topographical survey using the terrestrial LiDAR, drilling
survey and high-density electrical prospecting for the typical deep-seated landslide along the
Highway No 4. As results of the project, we have examined the methods for the disaster prediction,
prevention and the countermeasure construction and early warning system.
Keywords: AHP, landslide, deep-seated landslide, landslide-mapping, risk assessment, early
warning system, disaster prediction, disaster prevention1077

October 2013, Hanoi, Vietnam

1078

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Crack identification in frame structuresby using the wavelet analysis of mode shapes
TranVan Lien1, Trinh Anh Hao2
ABSTRACT
Crack identification in structures is very important and attractive for many
researchers. However, most of the published works deal with the simple structures
such as beam or plates. There are few papers devoted to study frame structuresthat could be mostly investigated only by using the conventional finite element
method. The present report deals firstly with a development of the dynamic
stiffness method for modeling framed structure damaged to multiple cracks
represented by equivalent springs. Then, the dynamic stiffness model of cracked
frame is implemented to the problem of crack identification from structural
vibration characteristics in conjunction with the wavelet analysis. The theoreticaldevelopment was illustrated and validated by numerical examples.
Keywords: Crack Identification; Mode Shape; Wavelet Analysis; Dynamic
Stiffness Method.
1. Introduction
The problem of crack identification in structure has attracted a considerable
attention of engineer-researchers for several recent decades due to its practicalimportance. A lot of procedures have been emerged to detect and quantify cracks
in structures [1]. Among the numerous proposed methods the wavelet-based
approach shows to be the most effective, especially for detecting the small local
damage such as crack in structures [2-5]. However, most of the published works
deal with the simple structures such as beam or plates by using the analytical or
the semi-analytical method. There are few papers devoted to study space frame
structures that could be mostly investigated only by using the conventional finite
element method (FEM).
Surace and Ruotolo [6] stated that presence of a crack in a cantilever beam
can be detected by the wavelet coefficient distribution computed from the time
history response measured at free end. Liew and Wang [7] demonstrated thatsingle crack in a simply supported beam can be localized from spatial wavelet
transform of free vibration response measured along the beam length at a given
time moment. This study was then continued by Wang and Deng [8] for the caseof impulse response of beam and plate with different boundary conditions. Douka
et al. [9] have achieved at identifying both the location and size of single crack in
1

Corresponding Author, Associate Professor, Ph. D, Faculty of Civil Engieering, University of
Civil Engineering, 55 Giai Phong Road, Hanoi, Vietnam, Tel: (84) 4 3869 1435; Email:
LienTV@hotmail.com;
2
Master of Civil Engieering, V-CIC, Hanoi, Vietnam, Email: TrinhAnhHao@yahoo.com

1079

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnama cantilever beam by using the wavelet coefficient distribution along the beam
length of the fundamental mode shape. The crack depth is estimated by so-called
the intensity factor related to the wavelet maxima coefficient. Chang and Chen
[10] have proposed a method for estimating both the position and depth ofmultiple cracks in beam based on the spatial wavelet transform of mode shapes.
The crack depth evaluation has been simplified by using the estimated crack
positions and available natural frequencies. This idea was then extended by Zhang
et al. [11] to multiple crack detection for stepped beam with involved the transfer
matrix method. Rucka and Wilde [12] reported that choosing properly wavelet
function is important for crack detection in structure. Zhong and Oyadiji [13]demonstrated that the stationary wavelet transform is a useful tool for crack
detection from only the mode shape of cracked beam-like structure. Gokdag andKopmaz [14] have proved that the approximation component of the wavelet
decomposition is similar to the mode shape of undamaged structure so that it canbe employed as the base-line data for conducting a damage index based on
differences of the wavelet coefficients. The proposed methods for crack detection
based on the spatial wavelet transform requires a high space resolution that
implies also a large number of sensors needed for measuring the response signal.
Zhu and Law [15] have employed the time domain response measured at a point
in a beam subjected to moving load as the input signal for the wavelet analysis.
The crack position can be determined easily from the continuous wavelet
coefficient plotted versus position of moving load. The most of the publishedworks have been devoted to apply the wavelet transform for crack detection in
beam-like structures. A simple plan frame with cracks subjected to static load has
been exceptionally investigated by Ovanesova and Suarez in reference [16] where
the static response was obtained by the FEM. The actual position of crack isobservable on the wavelet coefficient distribution but dominant ridges areapparent at the frame corners. Therefore, the wavelet-based approach to the crack
detection for frame is a gap that has to be fulfilled.
The objective of the present report is to apply the powerful wavelet-based
method for crack identification in framed structures. First, the dynamic stiffness
method (DSM) is enhanced to conduct the more accurate dynamic model ofmultiple cracked frame structures that allows for obtaining mode shapes. Then,the stationary wavelet transform is applied for crack detection from spatial
wavelet coefficient of the structure mode shapes. A case study has beenaccomplished to investigate also the influence of measurement noise on the
wavelet coefficients.
2. The mode shapes of a multiple cracked beam element
Let us consider a beam of length L subjected to bending on surface Oxy,cross-section area A=bh, moment of inertia I and Young's modulus E, massdensity . Free vibration of the beam is described by the following equation [17]:d 4 ( x,  ) 4 ( x,  )  0
(1)
dx 4
Where
(x,) denotes
complexamplitudeofthevibration; A  i 2   4 2
 ; i   1 is the dynamic parameter; Eˆ  E (1  i1 ) is
1  Eˆ I z 1080

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complexcomplexcomplexmodulus;modulus;modulus;1,1, 2 
are
the
are
materialmaterial
the material
andandviscousviscousand viscousdamping
damping
dampingcoefficients,
coefficients,
coefficients,
2 1,are2 therespectively;
respectively;
respectively;
 is
 the
is thecircular
iscircular
the circularfrequency
frequency
frequency(rad/s).
(rad/s).
(rad/s).
When
When
When
=0
=0
corresponding
corresponding
=0 corresponding
to to
=0
=0
to =0
it is
it aisstatic
aitstaticis deformation.
a static
deformation.
deformation.
SupposeSupposeSupposethat
thatthethe
that
beam
beam
the hasbeam
hascracks
crackshas cracks
at atpositions
positionsat positions
xj xwith
xthe
thedepths
depthsthe depths
of ofaj,aj,of aj,
j withj with0x0x1x10x2 x
x21...
 ...
x2xnx...
n1xxnn
xL L1).(Fig.
j=1,2,...,n,j=1,2,...,n,j=1,2,...,n,where
wherexwhere
1).TheThe1).cracks
cracks
The cracks
areare are
0 x
00
n x
1L
n(Fig.
1 (Fig.
z z
zmodeledmodeledmodeledas asrotationalrotationalas rotational
springs
springs
springs
withwiththewith
thestiffness
stiffnessthe stiffness
k j k calculated
k j calculated
bybyconverting
convertingby converting
j calculated
formulasformulasformulas
[17,
[17,
18].
18].
[17, 18].
y y
y
P1 P1
P1

P3 P3

.... ....
P2 P2
u2 u 2

uP1 2 u1
u2

NodalNodal

x=0x=0

u1k1 k1
x1 x1

k2 k2
x2 x2

k1
x1

k2
x2 L L

P3
x x

....
kn kn
xn xn

L

kn u3 u3
Pu43 P4xnu 4 u4u4

Nodal

NodalNodal

x=0

x=Lx=L

Fig.
Fig.
1: 1:
Modeling
Fig.
Modeling
1: Modelingof ofa multiple-cracked
a multiple-crackedof a multiple-cracked
beam
beam
element
beam
element
element

x
P4

Nodal

x=L

The
The
generalgeneralThe generalsolutionsolutionsolutionof ofequation
equationof equation(1)(1)
forforthe(1)thesub-segmentforsub-segment
the sub-segment
j=1,
j=1,
2, 2,
...,
j=1,
...,
n+1
2,
n+1
...,
with
with
n+1 with
xx(x
xx
j-1
(x,j-1,j)x(xjhas)j-1has, thexj)theform
hasform
theof:formof: of:x) (x) K K( (x)Kx) (x) K4K(4 (x)Kx) (x) K3K(3 (x) K



)K
j 1(K(x)1 (x) ZxK)j1Z
,1) Z j21,12  Z2jZ
j 1, 2 3 3Z4jZ
j 1,3 2 2Z3jZ
Z; jx1,x4 ;x xjx1 jx1 x j 1
j ( xj )( x
(1
,1j 1x
1,j21
,2 Z
1,j331
,3 Z
1,j41;, 4 x Eˆ IEzˆI z  Eˆ I z  Eˆ IEzˆI z  Eˆ I z 2(2)(2) (2)Krylov
Krylovare Krylov
functionsfunctionsfunctionsandandZ jZ
areare parameters
initialparametersparametersof ofthis
thisofsubsubthis subWhere
Where
Where
Ki(x)
Ki(x)areKarei(x)1,ij 1are
,i Z
and
jinitial
1,iinitial

segment:
segment:
segment:

 cos
 sin
 sin
 cos
x xsinhxx 
x sin xcosh
cosh
x xcoshcos
xx x cos x coshcoshx xcoshcos
xx x cos x sinh
sinh
x xsinhsin
xx 
x sin x sinh
sinh
sin
K1K
( x1)( x)K1 ( x) ; K;3K( x3)( x;)K3 ( x) ; K; 2K( x2)( x;)K2 ( x) ; K; 4K( x4)( x;)K4 ( x) 
2 2
2
2 2
2
2 2
2
2 2
2
T T
T
T
 
 
 
  T T ˆIE0ˆ
);( xE
ˆ(Ixˆ(Ix Z Z , Z,ZZ , Z, ,ZZ , Z, ,ZZ , Z  (x (x 0();x0);(x0( );x 0();x0Eˆ);IEˆ
I0 0();x0);EI);
( xE 0()x0)  0)

    

1,11, 2 j 1j ,j31,12, 3 j 1j ,j41,13, 4
j 1,1j 1,1 j 1j,j2

j 1, 4j 1 j 1

j 1

j 1 j 1

j 1 zz

j 1z j 1

j 1

z

z

j 1zj 1


j 1



ByBy
using
using
Bythe
using
the
combination
combination
the combinationof ofdynamic
dynamicof dynamic
stiffness
stiffness
stiffness
andandtransfertransferand transfer
matrixmatrixmethods,
matrixmethods,
methods,
wewe
yield
yield
we
[18]:
yield
[18]: [18]:P1PP12 PP23PPP134PP2T4 PT3 PK4eKT. eu1. uuK12 euu2.3uuu134uu2T4 uT3 u 4 T(3)(3)

(3)

The
The
matrixmatrixThe [K
matrix[K[Kis
is
calledcalledisthe
calledthedynamic
dynamic
the dynamic
stiffness
stiffness
stiffness
matrixmatrixformatrixforthethemultipleformultiple
the multiple
crackedcrackedcracked
e]4x4
e]4x4
e]4x4
beam.
beam.beam.
Using
Using
the
Using
the
generalgeneralthe generalsolutionsolutionsolution(2)(2)
andand(2)equation
equationand equation(3),(3),wewe(3),cancanwedetermine
determinecan determine
thethefree
free
the freeCrackidentificationin frame
bystructures
using
the
waveletanalysisof modeshapesCrack
identification
in
frame
by
the analysis
waveletanalysis
of
mode
Crack
Crack
identification
identificationin framein structures
frame
structures
structures
by by
using
using
theusing
thewaveletwaveletanalysisof modeof modeshapesshapesshapes1081

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamvibration shape function of multiple cracked beam elements. For example N1, we
determine the nodal forces P1 and P2 based on equation (3) with the following
condition u1  1 ; u 2  u 3  u 4  0

 P1   k11
   
 P2   k 21

k12

k13

k 22

k 23

k14 
k 
1 0 0 0T   11 
k 24 
 k 21 

The initial parameters of first sub-segment (j=1) are:

Z 0  Z 1 (0)  1; Z 2 (0)  0; Z 3 (0)  k11 ; Z 4 (0)  k 21Therefore, the shape function N1 for the first sub-segment is:N1(1)  K1 ( x) K 3 (x )K 4 (x )
k
k 21

11
Eˆ I 3
Eˆ I 2z(4)z

By using transfer matrix method, we get the shape function N1 for the next
sub-segment. In the case of intact beam, the shape function has the formula:
~ ~
~ ~
~
~ ~
K K K K
K2 K KN1  K1 (x)  ~1 2 2 ~ 3~ 4 K 4 (x)  ~ 22 ~ 1 ~3 K 3 (x)(5)
K3  K2 K4
K3  K2 K4~
where K i  K i (L) . When damping coefficients are zeros 1   2  0 , one will
get the shape function N1 determined by Leung [19].
The dynamic stiffness matrices of structure Kˆ ( ) are assembled similarly as
FEM from the dynamic stiffness matrices [Ke] of each beam elements. Thus, theproblem of free vibration of structures with the multiple-cracked bar elements
leads to the determination of natural frequencies and mode shapes from thefollowing equation:Kˆ ( )U  0(6)Where the natural frequencies j are determined from the equation:
det Kˆ ( )  0(7)

The nodal displacements U corresponding to the natural frequencies j will
be determined by equations (6). Having obtained the nodal displacements
u1 ; u 2 ; u3 ; u 4 , we receive the mode shapes of the structure with the multiplecracked beam elements from the expression:wx   N 1 x u1  N 2 x u 2  N 3  x u 3  N 4  x u 4

(8)

3. Wavelet analysis

Wavelet analysis starts by selecting a basis function from wavelet families.
This function is called “mother wavelet” ψ(x). The continuous wavelet transform

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ICUS Report 73(CWT) is then defined as:

C a, b  1 xb
f  x  dx   f  x  a,b  x dx

a 
 a 


(9)

Where a>0 and b are dilation scale and transition parameter; ψa,b(x) is function:
a ,b

x   1   x  b 
a



a

(10)



The result of CWT is wavelet coefficients C(a,b) showing the correlations
between the wavelet function and the signal analyzed f(x). Hence, sharptransitions in f(x) create wavelet coefficients with large amplitude and this
precisely is the basis of the proposed identification method.
The initial signal f(x) can be reconstructed from the wavelet coefficientsC(a,b):f x  

 

1
dbda
C a, b  a ,b  x  2K    a(11)

where the constant K depends on wavelet type.
Assuming that wavelet coefficients are valid only for a<a0, appropriate forhigh-frequency components in the signal, for a>a0, seen as interference. In thiscase, the signal reconstruction needs the complement corresponding to a>a0. To
do this, another function (x) called “scaled function” is used: xb
1




f
x

dx

f x a 0 ,b  x dx a a0 
 0 
Da0 , b  (12)The scaled function is nessesary for numerical implementation. Instead of(11), the initial signal f(x) can be reconstructed from:f x  

a





dbda
1 0
1
C a, b  a ,b  x  2 Da0 , b a0 ,b  x dbK a0 baK a0 b

(13)
One drawback of the CWT is that a very large number of wavelet coefficientsC(a,b) are generated during the analysis. In order to reduce the amount ofcomputation, the discrete wavelet transform (DWT) used discrete scale andtranslation parameters in dyadic form: a  2 j ; b  k .2 j where j and k are integers,
the integer j is referred to as the dyadic level. And the DWT is as follows:
C j,k  2

 j/2





 f x  2 x  k dx   f x  x dx



j

j,k

(14)



Where ψj,k(x) is discrete wavelet function:

 j , k  x   2 j / 2 2 j x  k (15)Instead of (11), the signal in DWT can be reconstructed from the wavelet
coefficients Cj,k:Crack identificationin frame structuresusing the bywaveletof modeshapesCrack identificationin framebystructuresusing analysis
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October
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Vietnamf  x     C j , k 2 j / 2 2  j x  k



(16)

j   k  

The signal will be passed through a series of filters, the high-pass filters andlow-pass filters, to generate high-frequency and low-frequency components,
respectively. Instead of (13), the signal in DWT can be represented byapproximations and details:
J
 
 
f  x      cD j k  j ,k  x    cAJ k  j ,k  x    D j x   A j  x 
j    k  jJ
 k  (17)

Where Aj(x) is the approximation at level J; Dj(x) is the detail at level j≤J:k  k  

D j  x    cD j k  j ,k  x  ; A j  x    cAJ k  j ,k  x (18)

cDj and cAj are detail coefficient and approximation coefficient, respectively:








cD J k    f  x  J ,k  x dx ; cAJ k    f  x  J ,k  x dx(19)

For this study, we are interested in the detail signal. A it will be shown with
the numerical examples, if f(x) is response signal, typically the deflection curve,
the signal Dj(x) contain the information necessary to detect the cracks in the
structure.
But the classical DWT suffers a drawback that it is not a time-invariant
transform. This means that, even with periodic signal extension, the DWT of atranslated version of the original signal is not, in general, the translated version of
the DWT of the original signal. To circumvent this problem, one can resort to a
redundant decomposition of signal as [13]




~
~
xk
xk
D j ,k  2  j / 2  f  x   j dx ; A j ,k  2  j / 2  f  x   j dx
 2 
 2 


(20)

The modified approximation and detail coefficients (20) constitute the socalled stationary wavelet transform (SWT) that has a great potential in signal
processing for structural health monitoring.
It should be noted that the SWT of the origin data is not decimated. That is,
the size of the SWT data does not diminish after the transform. Conversely, in
DWT, the resulting transformed data are half of the original signal size. Thus,
DWT is a down-sampling process which results in a poorer representation of theoriginal signal. Conversely, SWT is an up-sampling process which leads toredundant representation of the origin signal. Therefore, the detail coefficient of
DWT decomposition has less feature information than that of SWT. Consequently,
SWT has great potential for feature extraction and facilitates the identification ofsalient features in a signal.
4 Numerical results and discussion

For illustration a planar frame consisting of 6 two-dimensional beam

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elements as shown in Figure 2a is considered. All the beam have the same crosssection b×h=0.14×0.24m2; Young’s modulus E=3.5×1010N/m2; Poisson ratio
ν=0.3 and mass density =2500kg/m3. Two major scenarios of cracked frame are
adopted such as (a) multiple cracks of different location and depth occurred in abeam and (b) both the beam and column elements are damaged to cracks. First
three mode shapes of the undamaged structure are shown in Figures 2b-d.
Eigenmode:1a)Eigenmode:2

5

5

5

4

4

4

3

3

T w o -s to re y

2

2

2

1

1

1

0

0.5

1

1.5
Span(m)

2

2.5

b)

0
-0.5

Eigenmode:3

6

T w o -s to re y

6

T w o -s to re y

6

3

0

0.5

1

1.5
Span(m)

2

2.5

3

c)

0
-0.5

0

0.5

1

1.5
Span(m)

2

2.5

3

d)

Fig. 2: A frame structure model (a) and its first three undamaged mode shapes (bd).
Case 1: cracked beam of number 3. The detail wavelet coefficients of first
three mode shapes in element 3 cracked at distance 0.6m from the left end (node3) are given in Figures 3. Obviously, crack position is not detectable from theoriginal mode shape; however, it is apparent in the detail wavelet coefficient
distribution along the beam span. Of course, the spike at the crack position gets tobe higher for increasing crack depth (10%, 20%, 30%). The wavelet coefficientsin the case of two cracks occurred at distances 0.4m and 0.9m from the node 3 ofthe element 3 are shown in Figures 4. Even the two cracks have the same depth(10%, 20%, 30%) the high of the wavelet coefficient spikes is different in
dependence on the mode number. Namely, for the first and second modes thecrack closed to the node 3 is more apparent and it is in contrary for the third modeshape.

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SWT of eigenmodes: 1 dB 4

x 10

8

-6

5
10 %
20%
30%

6

-5

SWT of eigenmodes: 2 dB 4

x 10

3

SWT of eigenmodes: 3 dB 4

x 10

5
10 %
20%
30%

4

10 %
20%
30%

4
3

4
2

0
-2

Detail difference

Detail difference

Detail difference

2
2

1
0
-1

1
0
-1
-2

-2
-4

-3

-3

a)

-6
-8

0

20
-6

4

40

60
Distance [cm]

80

100

-5

120

0

20

40

-6

SWT of eigenmodes: 1 dB 4

x 10

60
Distance [cm]

80

100

-4
-5
0

120

20

40

-5

SWT of eigenmodes: 2 dB 4

x 10

2.5

10 %
20%
30%

3

b)

-4

2.5
10 %
20%
30%

2
1.5

60
Distance [cm]

80

100

120

c)

SWT of eigenmodes: 3 dB 4

x 10

10 %
20%
30%

2
1.5

2

0
-1

1
Detail difference

Detail difference

Detail difference

1

1

0.5
0
-0.5

0.5
0
-0.5

-1

-1

-1.5

-1.5

-2
-3
-4

0

20

40

-6

1.5

x 10

60
Distance [cm]80

SWT of eigenmodes: 1

dB 4

100

120

d)

-2.5

0

20

40

-7

10

60
Distance [cm]

SWT of eigenmodes: 2

x 10

80

100

40

x 10

60
Distance [cm]80

SWT of eigenmodes: 3

dB 4

100

f)

120

i)

10 %
20%
30%

10
8
6

Detail difference

Detail difference

5
Detail difference

20
-6

12

10 %
20%
30%

0.5

0

4
2
0

0

-2

-0.5

-1

120

-2
-2.5
0

120

dB 4

10 %
20%
30%

1

e)

-2

0

20

40

60
Distance [cm]

80

100

120

g)

-5
0

20

40

60
Distance [cm]

80

100

h)

-4
-6

120

0

20

40

60
Distance [cm]

80

100

Fig. 3: The detail wavelet coefficients of first three mode shapes in the element 3
with a crack at distance 0.6m from node 3.

-6-6

SWT of eigenmodes: 1 dB4

x 10

2
10 %
20%
30%

2

SWT of eigenmodes: 3 dB4

x 10

10 %
20%
30%

2

1
1
Detail difference

Detail difference

3
10 %
20%
30%

1.5

1.5
1
0.5
0

0.5

0

0

-1

-0.5

-0.5

-1
-1.5
-2

-5

SWT of eigenmodes: 2 dB4

x 10

Detail difference

3
2.5

0

20

40

60
Distance [cm]

80

100

a)

120

-1

-1.5

0

20

40

60
Distance [cm]

80

100

b)

120

-2

-3

0

20

40

60
Distance [cm]

80

100

c)

120

Fig. 4: Detail wavelet coefficients of the first three mode shapes for the element 3
with two cracks at distance 0.4m and 0.9m from the left end.
Case 2: Cracked beam and column. Suppose that the column (first element)
and the beam (third element) are both cracked. The wavelet coefficient
distribution for the first three mode shape in the case of a crack at the distance 1mfrom the fixed end of column 1 and a crack at the distance 0.6m from the left endof element 3 is plotted in Figures 5a-c. A crack at distance 2m is added to thecolumn element so that the frame gets to have three cracks and the wavelet
coefficients of the mode shape in the frame diagram are shown in Figure 5d-f.
From the Figures it can be noted that for the fundamental mode representing
mostly the vibration of column the crack closer to the fixed clamp make more
influence on the wavelet coefficients. In the second mode, influence of the crack
closed to the node 3 increased. The crack in the horizontal beam is more
detectable than that occurred at the column in the wavelet coefficient plot for thethird mode shape while it is visible also in the first and second mode shape
diagrams.

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SWT of eigenmodes: 1 Depth Cr= 30%

6

SWT of eigenmodes: 2 Depth Cr= 30%

6
dB4

5

4

4

4

3

2

3

0

0.5

1
1.5
2
Span(m)SWT of eigenmodes: 1 Depth Cr= 30%

1

a)

2.5

-0.5

0

1
1.5
Span(m)SWT of eigenmodes: 2 Depth Cr= 30%

6

dB4

5

0.5

2

b)

2.5

0

T w o -s to re y

T w o -s to re y
-1

-0.5

0

0.5

1
Span(m)

1.5

2

3

1.5

2

2.5

2

2.5

c)

3

2

1

d)

2.5

1
Span(m)

4

1

1

0.5

dB4

5

2

2

0

SWT of eigenmodes: 3 Depth Cr= 30%

dB4

4

3

-0.5

6

5

4
T w o -s to re y

2

1

-0.5

dB4

3

2

1

0

T w o -s to re y

5-1

SWT of eigenmodes: 3 Depth Cr= 30%

65T w o -s to re y

T w o -s to re y

dB4

-1

-0.5

0

0.5

1
Span(m)

1.5

2

e)

2.5

f)
-0.5

0

0.5

1
Span(m)1.5

Fig. 5: The detail wavelet coefficients of first three mode shape in the case ofcracked column and beam
Case 3: influence of the noise. The natural mode shapes of the frame cracked
at distance 0.6m of the beam element 3 have been computed and added with aGaussian noise generated by Matlab function Rand(n). For the modal deflection of
the element denoted by vector Y ={y1,..., yN } the noise vector is introduced byy noise 

y nrnorm yint act .
norm y nr  10 0.05SNR (21)where ynr =Rand(size(yintact)) and SNR is the signal to noise ratio measured indecibel (dB). The noise level SNR examined in this study is of 75, 80 and 95dB
and the wavelet coefficients of the noised first two mode shapes are given in
Figure 6. It can be seen from the Figure that the crack position can be clearly
detected by using fundamental mode shape if the SNR exceeds 80dB while using
the second mode shape enables a crack to be exactly localized for the noise levelfrom 75dB.
-7

5

x 10

SWT of eigenmodes: 1

Depth Cr= 30%-7

SNR= 75db
6x 10

SWT of eigenmodes: 1

Depth Cr= 30%

3

1
0
-1

0

-3

-2

-4
-5

0

20
-7

6

x 10

40

60
Distance [cm]

SWT of eigenmodes: 280

Depth Cr= 30%

100

120

a)

0

20

-7

SNR= 75db
5

x 10

40

60
Distance [cm]

SWT of eigenmodes: 280

Depth Cr= 30%

100

b)

2
1
0

-2

60
Distance [cm]

80

100

0

20

-7

5

x 10

40

60
Distance [cm]

SWT of eigenmodes: 2

80

100

Depth Cr= 30%

SNR= 90db

120

d)

4

3

3

2

2

1
0

c)

120

f)

1
0
-1

-2
-3

120

dB4

4

-1

-1

40

-4

Detail difference

Detail difference3
Detail difference

120

-2

dB4

4

20

2

SNR= 80db

dB4
5

-3
0

SNR= 90db

0

-3
-4

Depth Cr= 30%

4

1

-1

SWT of eigenmodes: 1

dB4

2

-2

x 10

6

Detail difference2
Detail difference

Detail difference

4

8
dB4

5

3

-7

SNR= 80db

dB4
4

0

20

40

60
Distance [cm]

80

100

120

e)

-2
-3

0

20

40

60
Distance [cm]

80

100

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5. Conclusion

Thus, in this report the DSM has been developed for more accurate dynamic
analysis of space framed structures with multiple cracked 3D beam elements; The
SWT has been applied to spatial signals associated with the natural vibration
mode shapes computed by using the developed DSM. The illustrating numericalresults verify that the developed dynamic model of cracked frame structures
combined with the SWT can be reliably employed for localization of cracks inframe structures with data contaminated with noise of SNR from 75dB. The
subsequent study is to estimate crack size from the wavelet coefficients.
References[1] H. Sohn, C.R. Farrar, F.M. Hemez et al (2004), A Review of Health
Monitoring Literature 19962001, Los Alamos National Laboratory, Los
Alamos, New Mexico, Report No LA13976-MS.
[2] W.J. Staszewski (1998), “Structural and Mechanical Damage Detection Using
Wavelets”, The shock and Vibration Digest, 36, 3443-3468.
[3] Z. Hou, M. Noori and R.St. Amand (2000), “Wavelet-Based Approach for
Structural Damage Detection”, Journal of Engineering Mechanics, Vol 126(7), 677-683.
[4] S.T. Quek et al (2001), “Sensitivity Analysis of Crack Detection in Beams by
Wavelet Technique”, International Journal of Mechanical Sciences, 43,
2899-2910, 2001.
[5] M.M. Reda Tana et al. (2006), “Wavelet Transform for Structural Health
Monitoring: A Compendium of Uses and Features”, Structural Health
Monitoring, Vol 5(3), 267-295.
[6] C. Surace and R. Ruotolo (1994), “Crack Detection of a Beam Using WaveletthTransform”, Proceedings of the 12 International Modal Analysis
Conference, Honolulu, Hawaii, pp.1141-1167.
[7] K.M. Liew and Q. Wang (1998), “Application of Wavelet Theory for Crack
Identification in Structures”, Journal of Engineering Mechanics, 124, 152–
157..
[8] Q. Wang and X. Deng (1999), “Damage Detection with Spatial Wavelets”,
International Journal of Solid and Structures 36, 3443-3468.
[9] E. Douka, A. Loutridis and A. Trochidis (2003), “Crack Identification in
Beam Using Wavelet Analysis”, International Journal of Solid andStructures, 40, 3557-3569.
[10] C.C. Chang and L.W. Chen (2005), “Detection of the Location and Size of
Cracks in the Multiple Cracked Beam by Spatial Wavelet Based Approach”,
Mechanical Systems and Signal processing, 19, 139-155..
[11] W. Zhang, Z. Wang and H. Ma (2009), “Crack Identification in Stepped
Cantilever Beam Combining Wavelet Analysis with Transform Matrix”,
Acta Mechanica Solida Sinica, Vol 22(4), 360-368.
[12] M. Rucka and K. Wilde (2006), “Crack Identification Using Wavelets onExperimental Static Deflection Profiles”, Engineering Structures, 28, 279-

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288.
[13] S. Zhong and O. Oyadiji (2007), “Crack Detection in Simply Supported
Beams without Baseline Modal Parameters by Stationary Wavelet
Transform”, Mechanical Systems and Signal processing, 21, 1853-1884.
[14] H. Gokdag and O. Kopmaz (2009), “A New Damage Detection Approach for
Beam-type Structures based on the Combination of Continuous and Discrete
Wavelet Transforms”, Journal of Sound and Vibration, 324, 1158-1180.
[15] X.Q. Zhu and S.S. Law (2006), “Wavelet-based Crack Identification of
Bridge Beam from Operational Deflection Time History”, International
Journal of Solid and Structures, 43, 2299-2317.
[16] A.V. Ovanesova and L.E. Suáres (2004), “Applications of Wavelet
Transforms to Damage Detection in Frame Structure”, Engineering
Structures, 26, 39–49.
[17] N.T. Khiem and T.V. Lien (2001), A simplified method for natural frequency
analysis of a multiple cracked beam, Journal of Sound and vibration, 2001,
245(4): 737-751.
[18] N.T. Khiem, T.V. Lien (2002), “The dynamic stiffness matrix method inforced vibration analysis of multiple cracked beam”, Journal of Sound andVibration, 254(3), 541-555.
[19] Y.T. Leung (1993), Dynamic Stiffness and Substructures, Springer-Verlag,
London.
[20] N.T. Khiem, T.V. Lien, D.T. Hung and T.A. Hao (2013),”Crack
identification in frame structures by using the spectral element method andwavelet transform”, Proceedings of the 6th ECCOMAS Conference on Smart
Structures and Materials, SMART2013, 24-26 June 2013, Italia.

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Mechanical behavior of high damping rubber
bearings at low temperatures
Dung Anh NGUYEN1, Yoshiaki OKUI1, Md. Shafquat HASAN1, Hiroshi
MITAMURA2, Takashi IMAI3,
1
Department of Civil and Environmental Engineering, Saitama University, Japan.
s10de007@mail.saitama-u.ac.jp
2
Civil Engineering Research Institute for Cold Region Sapporo, Japan
3
Rubber Bearing Association, Japan
ABSTRACTThe paper is devoted to identify the mechanical behavior of high damping rubber
bearings (HDRBs) at low temperatures. The rubber bearing tests were carried out
in an environmental test chamber at -30°C, -20°C, and 23°C ambient
temperatures. Sinusoidal loading tests with a frequency of 0.5 Hz were conducted
to investigate the low temperature dependence of HDRBs. The experimental
results indicate that the temperatures inside HDRBs are increased by sinusoidal
loading, and the rise in the inside temperature becomes larger at lower ambient
temperatures. In addition, it is shown that the stress-strain relationships of
HDRBs is governed by the inside temperatures but not by the ambient
temperature. Furthermore, the experimental results indicate that the hardening inthe stress-strain relationship of HDRBs is significant at low temperatures.
Therefore, the bilinear model cannot well represent HDRBs’ behavior at low
temperatures.
Keywords: high damping rubber bearings, self-heating, inside temperature,temperature dependence.
1. INTRODUCTION
High damping rubber bearings (HDRBs) are seismic isolating devices used widelyin Japan, especially after Kobe earthquake in 1995. However, the mechanicalbehavior of HDRBs depends on temperatures and this dependence may affect theperformance of the bearings, especially at low temperatures.
In the previous experimental investigations (Imai et al., 2010; Pinarbasi et al.,2007) considering the temperature dependence of mechanical behavior of rubber
bearings, the ambient temperature in a test chamber is assumed to equal the insidetemperature of rubber bearings. However, when subjected to cyclic loading, theenergy dissipated by HDRBs is converted into heat and this heat may causesignificant temperature rise inside rubber bearings. Takaoka et al, (2008) indicatedthat sinusoidal cyclic loading caused the inside temperature to rise by about 300C
at room temperature, which leads that the yield load of bearings drops to about
80%. Therefore, the relationship between increased temperatures and themechanical characteristics of rubber bearings is a serious concern.

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In current guide specifications (AASHTO, 2000; JRA, 2002) for the seismic
design of bridges with HDRBs, the nonlinear characteristics of HDRBs are
expressed in terms of a bilinear model. However, the experimental observations(Bhuiyan et al., 2009; Dall’ Asta and Ragni, 2006) have shown that themechanical behavior of HDRBs is characterized by the strain hardening behavior.
The current bilinear model cannot represent this behavior.
The final goal of the research project is to develop a design procedure of HDRBs
at low temperatures. As the first step, rubber bearing tests were conducted to
identify the mechanical behavior of HDRBs at low temperatures. The
experimental results are presented in this paper to discuss the temperaturedependence of HDRBs.
2. EXPERIMENTS
2.1 Specimens
All specimens had square cross-sectional shape. The reinforcing steel plates had
similarly a square planar geometry with thickness of 2.3 mm. The dimensions andmaterial properties of the specimens are given in Table 1. In order to remove
stress-softening due to Mullins effect, all specimens were preloaded before theactual tests.
Table1. Dimension and material properties of HDRBs
Particulars
Specifications
Cross-section (mm2)
240x240
Number of rubber layers (mm)6Thickness of one rubber layer (mm)5Thickness of one steel layer (mm)2.3
Nominal shear modulus (MPa)
1.2
2.2 Test conditions
The rubber bearing tests were carried out in an environmental test chamber with acomputer-controlled servo-hydraulic testing machine at -30°C, -20°C, and 23°C
ambient temperatures. All specimens were tested under shear deformation with aconstant vertical compressive average stress of 6 MPa. The displacement wasapplied to the top edge of the specimen and the force response was measured with
two load cells. The output data were recorded by using a personal computer.
The temperatures inside the specimens are measured by installing thermocouples.
The positions of temperature measurement in the central section are shown in Fig.
1. Eleven sinusoidal loading cycles were applied on the specimens with a shear
strain amplitude and frequency of 1.75 and 0.5Hz, respectively.

Fig.1. Measure points of temperatures (Japan Rubber Bearing Association)

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3. EXPERIMENTAL RESULTS AND DISCUSSION
The measured temperatures inside the specimens and the cumulative dissipatedenergy are presented in Fig. 2. The cumulative dissipated energy density is
calculated by11D   Di

(1)

i 1

where Di is the dissipated energy density of the ith cycle, and Di can be calculated
from the enclosed area of a stress-strain hysteresis loop for one cycle. Fig. 2
shows that the temperatures inside the bearings are increased by cyclic loading.
The rise in the inside temperature and the cumulative dissipated energy are larger
at lower ambient temperatures.
Assuming that all dissipated energy is converted into the heat energy, thetemperature increase △T in a sinusoidal test is estimated from the dissipatedenergy density under the adiabatic condition for only rubber part:(2)
DVr  C pr mr T
where Cpr is the specific heat of rubber; mr and Vr are the mass and volume ofrubber, respectively.
On the other hand, considering a rubber bearing as composite of steel and rubber,and assuming that the temperature increases in the rubber and steel are the same,the temperature increase can be estimated fromDVr  C pr f  C ps 1  f  mr T
(3)





where Cps is the specific heat of steel; m=mr+ms stands for the total mass; ms isthe mass of steel; f  mr / m is the mass fraction of rubber.
In this calculation, the specific heats for rubber and steel are assigned to Cpr =1.732 J/g.K, and Cps = 0.432 J/g.K, respectively (Uruta et al., 2004). The
estimated temperatures are higher than the measured temperatures in Fig. 3
because the some heat transfers from the specimen to the ambient environment in
the measurement.
In Fig. 2, the 7th cycle of the test at -30°C ambient temperature and the 4th cycle ofthe test at -20°C ambient temperature have the same inside temperature of -10°C.
Fig. 4 presents that the stress-strain relationships of the two cycles give agreement
each other. It means that the stress-strain relationships of HDRBs is governed by
the inside temperatures, but not by the ambient temperature. Moreover, Takaoka
et al, (2008) showed that the temperature rises in bearings are very small under anearthquake. Therefore, a seismic model for HDRBs at low temperatures should bebased on the inside temperatures.
Fig. 5 presents the inside temperature dependence of stress-strain relationship of
HDRBs. It is clear that the area of hysteresis loop and the strain hardening of
HDRBs increase with decreasing the inside temperatures.
The shear modulus G and the damping constant hB are calculated from theexperimental results with G  max min(5) max   min
Di
hB 
(6)
2W

Mechanical behaviorof high
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at low temperatures1093

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Vietnamwhere W is the elastic strain energy density; max and min are the maximum andminimum shear stresses of rubber; and max, min are the corresponding shear
strains at max, min, respectively. The values of G and hB at different insidetemperatures are shown in Fig. 6. While the inside temperature decreases from
35oC to -22oC, G and hB increase 180% and 79%, respectively. It is clear thatthese parameters are significantly affected by the inside temperature variations.
The stress-strain relationship obtained from sinusoidal loading tests at -10oC
inside temperature is used to determine the parameters of the conventional
bilinear model. Fig. 7 shows the comparison of the bilinear model with thesinusoidal test result. The experimental result shows significant hardening at ahigh strain level, but the bilinear model cannot represent this feature. This is thelimitation of the bilinear model at lower temperatures.

(a)

(b)

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ICUS Report 73(c)Fig.2. Cumulative dissipated energy and temperatures at ambient temperatures (a)-30°C, (b) -20°C, and (c) 23°C.

Fig.3. Comparison of measured temperature with theoretical temperature at -30°C
ambient temperature.

Fig.4. Stress-strain relationships at -10°C inside temperature.

Mechanical behaviorof high
dampingrubberbearings
at lowtemperatures
Mechanicalbehaviorof high
dampingrubberbearings
at low temperatures

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Fig.6. Temperature dependence of shear modulus and damping constantFig.7. The comparison of the bilinear model with experimental result at -100C
inside temperature

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4. CONCLUSIONSThe temperatures inside HDRBs are increased by cyclic loading, and the rise in
the inside temperature becomes larger at lower ambient temperatures. In addition,
it is shown that the stress-strain relationships of HDRBs is governed by the insidetemperatures but not by the ambient temperature.
The conventional bilinear models for HDRBs in most seismic design codes are
determined based on a stress-strain relationship obtained from sinusoidal tests
after several cycles of loading to remove stress-softening behavior due to Mullins
effect. However, the present experimental results show that this procedureneglecting self-heating effect is not appropriate for development of seismic
models for HDRBs, especially at low ambient temperatures. Since the temperature
increase during an earthquake is considered not so large as that during a cycling
loading test, a seismic model for HDRBs at low temperatures should be based on
the inside temperatures.
In order to develop an estimation procedure of temperature increase during an
arbitrary strain history, the temperature increase in a sinusoidal test is estimatedfrom the dissipated energy under a simple adiabatic assumption. The measured
temperatures are lower than the estimated temperatures because there is the heattransfer in the actual condition.
Since the hardening in the stress-strain relationship of HDRBs becomessignificant at low temperatures of -20 and -30°C, the bilinear model is not well
representation of HDRBs’ behavior at low temperatures.
ACKNOWLEDGMENTS

The experimental works were conducted by utilizing the laboratory facilities andbearings-specimens provided by Japan Rubber Bearing Association. The authors
indeed gratefully acknowledge the kind cooperation extended by them.
REFERENCES

American Association of State Highways and Transportation Officials(AASHTO), 2000. Guide Specification for Seismic Isolation Design, 2/e.
Bhuiyan, A.R., Okui, Y., Mitamura, H., Imai, T., 2009. A rheology model of highdamping rubber bearings for seismic analysis : Identification of nonlinear
viscosity. International Journal of Solid and Structures 46, 1778-1792.
Dall’Asta, A., Ragni, L., 2006. Experimental tests and analytical model of highdamping rubber dissipating devices. Engineering Structures 28, 1974-1884.
Diani, J., Fayolle, B., Gilormini, P., 2009. A review on the Mullins effect.
European Polymer Journal 45, 601-612.
Hwang, J.S., Hsu, T.Y., 2001. A fractional derivative model to include effect of
ambient temperature on HDR bearings. Engineering Structures 23, 484-490.
Imai, T., Bhuiyan, A. R., Razzaq, M. K., Okui, Y., Mitamura, H., 2010. Joint
conference proceedings of 7CUEE & 5ICEE, Tokyo, Japan, 1921-1928.
Japan Road Association, 2002. Specifications for Highway Bridges, Part V :Seismic Degign.

Mechanical behaviorof high
dampingrubberbearings
at lowtemperatures
Mechanicalbehaviorof high
dampingrubberbearings
at low temperatures

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October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamKhan, A. S., and Lopex-Pamies, O., 2002. Time and Temperature Dependent
Response and Relaxation of a Soft Polymer. Intl. J. Plast 8, 1359-1372.
Lion, A., 1997. On the Large Deformation Behavior of Reinforced Rubber at
Different Temperatures. J. Mech. Phys. Solids 45, 1805-1834.
Pinarbasi, S., Akyuz, U., Ozdemir, G., 2007. An experimental study on low
temperature behavior of elastomeric bridge bearings. 10th world conference on
seismic isolation, energy dissipation and active vibrations control of structures,
Istanbul, Turkey, 28-31.
Takaoka, E., Takenaka, Y., Kondo, A., Hikita, M., Kitamura, H., 2008. HeatMechanics Interaction Behavior of Laminated Rubber Bearings under Large andCyclic Lateral Deformation. The 14th World Conference on Earthquake
Engineering, Beijing, China.
Uruta, H., Yamazaki, T., Ohsima, T., Nakamura, M., 2004. Experiments andnumerical analysis on response of internal temperature of high damping rubber
Bridge Bearing under low temperature. Proceedings of JSCE (Japan Society of
Civil Engineers) Vol. I, 773, 113-123.

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Examples of proposals for emergency
countermeasure and research methods oflandslide in Vietnam
Do Ngoc Trung １, Nobolu Fujii2, Seiichi Hujiwara2 and Shinro Abe2
1
Vietnam Japan Engineering Consultants Co., Ltd, Hanoi
mr.dongoctrung@gmail.com
2
Okuyama Boring Co., Ltd, Japan

ABSTRACTIn recent years, there have been a large number of cases of new landslides
occurring on road slopes, river banks and hilly areas of rapidly developing cities.
This increased number of occurrences of landslides in developing cities is
considered to be caused by the formation of manmade slopes due to road andresidential land developments, as well as torrential rain and floods that come withclimate change. Particularly in developing cities with little experience oflandslides where methods for stabilization have not been established, it isessential to investigate landslides and consider countermeasures urgently. We
investigated landslides occurring on the slopes along the road on the coast of HaLong Bay: a well-known World Heritage Site in Vietnam, using 1) boring surveys
with core pack tube, 2) fixed point observation to understand amount, direction,and the range of fluctuations, and 3) simple extensometers. Using these researchmethods which are easily prepared, installed, and observed in Vietnam, we
identified the mechanisms of landslides, and proposed the emergency construction.
It is thought these methods will become effective means against landslides in thedeveloping cities as mentioned above..
Keywords: landslide, slope disaster, landslide investigation, emergency
countermeasure

1. INTRODUCTION
In recent years, there has been a large number of cases of new landslides
occurring on road slopes, river banks, and hilly areas in rapidly developing
Vietnamese cities. This increased number of landslides occurring in developing
cities is considered to be caused by the formation of man-made slopes because ofroad and residential land developments, as well as heavy rain and floods that
occur with climate change. In Vietnam, where there is little experience oflandslides and methods for dealing with them have not been developed yet, it isnecessary to investigate landslides and urgently discuss countermeasures. For thelandslides occurring on the slopes along the road on the coast of Ha Long Bay, awell-known World Heritage Site and picturesque place in Vietnam, we identified
the landslide generation mechanism using survey techniques that will be easy for1099

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Vietnampreparation, installation, and observations in Vietnam. We also proposed
emergency construction work. It is thought that these techniques will form
effective means against landslides in the aforementioned developing cities fromnow on.

2. Overview of landslides in the Bai Chay Bridge area
The locations studied in this study are located on the southern edge of a hilly area,
at an altitude of less than 100 m, over a section of approx. 3.5 km encompassing
the Bai Chay Bridge, National Route 18, over the Ha Long Bay. They all mainly
correspond to cut slopes at an altitude of 10–70 m. Parts of the slopes areconstructed with wet masonry or cast-in-place concrete cribwork, but they aremostly bare. On these bare slopes, a number of slope deformation throughlandslides or weathering and erosion, as well as unstable conditions throughinstance rock fall are observed.
This study is focused on site No. 10, which particularly displayed marked
landslide deformations (Fig. 1).

Study site

N

3.5km

Study site

No.10
1km

Ha Long Bay

Figure 1: Survey location mapsz
The geology of this area is composed of sedimentaryrock from the Carboniferous
Period of the Paleozoic Era to the Triassic period of the Mesozoic era, such as
quartz conglomerates, quartz sandstone, siltstone, claystone, and carbonaceous
claystone (Department of Geology and Minerals of Vietnam, 2001) (Fig. 2).
The strike of the bed is roughly north–south, and multiple short-period folds ofseveral tens to hundreds meters on a north–south fold axis can be observed. As
National Route 18 in the area of our study traverses the northern edge of a hilly
area, there are many north-facing excavated road slopes. As the road slopes in ourstudy area are also north facing, the beds in the slope mainly dip with respect tothe slope direction. Most of the landslides in this area occur as translational
bedrock landslides in dip slopes in mud formations around the folding axes of thefold structures and the overfolds, amidst alternating strata of mudstone, sandstone,
and conglomerates.

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The Quaternary period
The Triassic period in
Mesozoic Era

Quartz conglomerate (yellow); mudstone,sandstone, quartz in alternating strata
Mudstone (grey-black),
encompassing a thin
local layer

3～5m

The Permian period in
the Paleozoic Era

Conglomerates, sand, clay

Figure 2: Pattern diagram of columnar section around the study area
3. Overview of the landslide at the study site (No. 10)
3.1 Topography, geology, and landslide conditions
Site No. 10 is a cut road slope, located on the southern edge of a hilly area at analtitude below 100 m. On this slope, a translational bedrock slide occurred
covering an area of approx. 50 m wide and 60 m long (photographs 1 and 2). At
the eastern edge of the landslide area, 3 m wide and 3–5 m deep openings(collapsed zones) (photograph 3) have formed. Inferring from the direction andthe strike and dip of this crevice, the landslide is thought to have moved to dip in anorthwesterly direction. The landslide tip is restricted by the fault on the westernside, changes its direction of movement into a northerly direction, and rises up
along the slope. On this slope, multiple short-period fold structures are observed,
and landslides have occurred in the area where the mudstone on top of the
anticline is exposed on the surface. The western edge of the landslide is in contact
with the fault (photograph 1).
On this site, a φ = 1 m rock fall occurred owing to heavy rain during a typhoon in
the fall of 2012.
50m

F

60m

N

Photograph 1: Overall scene. Solid line: landslide range; Arrows: direction of
movement; F: fault
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3～5m

3m

Photograph 2: Landmass moving as a
block

Photograph 3: Opening at the head of thelandslide

3.2 Problems with the response to landslide disasters in Vietnam
During the survey of site No. 10, rock fall movement could be observed to occur
during rain. Fragmentation of blocks accompanying landslides of the collapsed
zone at the top and the slope was also notable, and there was a high risk ofincreased activity. Because National Route 18, a main route, passes at the tip ofthe landslide, it was desirable that a landslide survey was conducted without delay.
The landslide mechanism was understood, and countermeasures were planned andimplemented.
Vietnam does not, however, have any established methods for detailed landslide
surveys, analysis, or countermeasure construction, and there are few past records
for the development or introduction of observation equipment. Landslide disasters,
therefore, either remain uninvestigated or are only analyzed through simple
investigations such as boring or seismic prospecting, and countermeasures merely
employ retaining walls to retain the soil or recutting at a low gradient.
We, therefore, improved the currently used technologies, employed methods ofsurveying, observation, and analysis using equipment that can be promptly
prepared, and proposed methods for countermeasure construction.

4. Survey and countermeasure methods for site No. 10
4.1 Used survey method and results
4.1.1 Survey methods and reasons for their use
Because of the urgency, a survey was planned and implemented for this site, after
a geological reconnaissance, with equipment that can be promptly prepared on site.
The survey employed survey boring, fixed point observations, borehole
inclinometer measurements, groundwater level measurements, and ground surface
extensometers.

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1. Boring surveys: In boring surveys, it isimportant to ascertain, by means ofcollected cores, the geological features,clay intercalation, and the distribution of
weak planes in crevices. Because in
Vietnam core, retrieval rates with theconventional core retrieving method
through a single core tube (photograph 4)
were poor and evaluation of the geology
and slip surface was difficult, we used adouble core tube and a core pack tube
manufactured in Japan for improving core
retrieval rates.

Photograph 4: Boring

2. Fixed point observations: In fixed point observations, simple mobile measuring
points (e.g., piles, survey pins) are placed inside the landslide and the surroundingarea, and the amount of horizontal and vertical movement is obtained throughtriangulation, distance measuring, and leveling. Through periodic measurements,
the amount and direction of landslide movement can be ascertained, and this canbe performed with regular measuring equipment.
3.
Borehole
inclinometer:
Borehole
inclinometers survey the borehole deformation
and assess the slip surface by placing pipes
using boreholes (Fig. 3). These are often used in
Vietnam to survey ground deformations when
digging tunnels or dam bodies.

Measuring
instruments
計器
キャプタイヤケーブル
Cap tire cable
根固コンクリート

Foundation concrete

4. Ground water level measurements: In groundwater level measurements, a perforated ventpipe is placed in a borehole and consecutive
ground water levels are measured with apiezometer. Assuming that ground water was
supplied to this landslide area, we set up an
observation hole in the collapsed zone at thehead of the landslide, where the ground waterlevel can be ascertained with a borehole ofminimum depth.

ガイドケーシング

Guide casing

ボーリング孔(φ86 ㎜)
ボーリング孔（φ85mm）

Boring hole(Ø 86 mm)Borehole

孔内傾斜計
高精度孔内傾斜計
inclinometer）

5. Ground surface extensometer: Ground surface
extensometers continuously ascertain landslide
movement through the expansion andcontraction of an inverter wire, which is placedin the moving part of the landslide and in thesurrounding stationary area, spanning thecrevice (Fig. 4). On this site, it was placed at the
ボトムキャップ
Bottom cap
upper part of the crevice and the end. We used a
Figure 3: Borehole inclinometerJapanese battery powered extensometer.
measuring example
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図3-6-1.

Extensometer
Wooden gutter or PVC pipe
Crevice

Inverter wirePole
図3-6-2.

Figure . 4 Extensometer set-up
4.1.2 Survey results
1. Boring survey results
Boring core retrieval in subsurface surveys in Vietnam is generally performed
using single core tubes. The fact is however that, because no casing is used or theboring machine has not been fixed, core retrieval rates are low (photograph 5). As
a result of our decision to use a core packing tube, which is recently being used at
Japanese landslide sites, and an excavation method, where the machine is fixed,
an improvement in core retrieval rates can be observed (photograph 5).

Conventional methods in Vietnam

Using a double core tube with
CORE PACK
Photograph 5: Comparing boring core photographs

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2. Fixed point observation results
Fixed point observation results, obtained using general surveying techniques,
showed that the direction of movement is at an almost direct angle to thecollapsed zone at the head. We confirmed the amount of movement to be adisplacement of maximum 80 mm in approx. 1 month
We established the direction of movement to be somewhat oblique to the directionof National Route 18 (Fig. 5).

The arrow indicates the vector
displacement.
0

100mm

Figure 5: Fixed point– vector displacement (measuring period: 28 days)(2012/10/22）

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3. Borehole inclinometer measurement results
Bends were observed at a depth of 6.50 m in borehole BV10-1-A (Fig. 6) and at a
depth of 6.00 m in borehole BV10-2-A (Fig. 7).
We ascertained that the slip surface, which was revealed by the inclinometer andthe survey boring, is a so-called dip slope rockslide following the stratum gradient(Fig. 8). The slip surface angle is approx. 25°.
BV10-2-A

BV10-1-A

Displacementμ"# m-0.200-0.1000.000-0.100
0.0

2.0

2.0

4.0

4.0

6.0

深
度

Displacement"# m μ0.100←slip surface

Depth mDepth m-0.300
0.0

8.0

0.000

0.050

0.100

←slip surface

6.0

深
度

m

-0.050

8.0

m

10.0

10.0

12.0

12.0

14.0

14.0

16.0

16.0
12.7.212.8.812.8.28

12.7.2

Figure 6: Borehole BV10-1-A
inclinometer displacement

12.8.28

Figure 7: Borehole BV10-2-A
inclinometer displacement
Vector displacement scale

Regerd表土12.8.8

Surface soil

Extensometer S1

粘土岩

Mudstone

シルト岩

Siltstone

砂岩

Sandstone

礫岩

Gritstone

想定すべり面

Assumed surface of rupture

BV10-2-A
2
BV10-2(R)GH+59.53m m
Dep.=25.00

1.00

BV10-1-A

2.00← slip surface

7.00

Extensometer S2

BV10-1
GH+47.15m m
Dep.=15.00

9.80← slip surface

09/25
GL.-4.08m(BV10-3を投影)

12.00

3.20
2012/
04/26
5.00
6.10
6.50
6.60

18.50

11.20

25.00

15.00

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4. Ground water level/extensometer results

5.0

250

4.0

200
150

ｍ

Rainfall

1.0
0.0

0

-1.0

-50

S-2

-2.0

-100

Ground water

-3.0

-150

-4.0

-200

-5.0

＋

50

Extensometer movement mm

Ground water level m

水
位

100

-250
8/28

9/4

2012

9/11

9/18

9/25

10/2

10/9

10/16 10/23 10/30

Date

11/6

11/13 11/20 11/27

Compression

2.0

－

S-1

3.0

TensionExtensometer S-1 was set up at the head, the stretching end of the landslide;
extensometer S-2 was placed at the passive tip of the landslide (Fig. 8). The
movement registered by the extensometers is concordant with ground water level
fluctuations, where they increased with rising ground water levels and decreased
with decreasing ground water levels (Fig. 9). We could therefore affirm that thelandslide at this site is greatly affected by increasing subsurface ground waterlevel accompanied by heavy rain.

Figure 9: Rainfall/ground water level fluctuations as registered by extensometers4.1.3 The landslide generation mechanism
On the basis of these survey results, the landslide generation mechanism can besummarized as follows.
This landslide is a rockslide, where the slip surface is formed by the mudrock
formation around the fold axis and the overfold area in the fold structure. Fromthe clear correlation that can be observed between ground water levels andlandslide movement, we concluded that the rapid rise of pore water pressure attimes of heavy rainfall forms the trigger for the landslide’s intermittent movement.
Countermeasures for these types of landslides can be considered to deal withsurface water at times of heavy rain, ground water drainage, counterweight fills,
or preventive work using anchors or piles.

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4.2 Countermeasure work planning
4.2.1 Stability analysis and analysis conditions
For the landslide stability analysis, the simplified Janbu method was used; for theslip surface strength, we employed C = 0 kN/m2 and φ = 22.39°, considering theslip surface gradient and the topographical incline. The design safety factor (PFs)
was set at PFs = 1.20, as the subject of preservation; main road National Route 18
forms the approach route to the Bai Chay Bridge, a tourist attraction, andfurthermore faces Ha Long Bay, a Unesco World Heritage Site.
Using these results, we planned emergency countermeasures focusing on
counterweight fill work and ground water drainage work for the rainy season from
June to September (Fig. 10).

Ground waterdrainage works

20m

Counter weight fill work

10

10m

0

0

Figure 10: Cross section of the emergency countermeasure
work plan
For the purpose of permanent stabilization after the emergency countermeasures,
we proposed slope protection work, focusing on anchor work, to prevent
destabilization by means of erosion control, with sensitivity to the surrounding
scenery.

5. Conclusion
We used a core packing tube together with the boring used in Vietnam at landslidedisasters and elucidated the landslide generation mechanism through economicaland basic landslide survey and measuring techniques using equipment that can beprepared promptly. These included fixed point observations using mobile
measuring points such as survey pins, ground surface extensometers using
inverter wires and extensometers, and borehole inclinometers using porous ventpipes. We also introduced examples of countermeasure proposals.
It is thought that these will form valuable techniques against landslide disasters
that are presumed to occur in future in developing cities.

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Ultra rapid strength development indry-mix shotcrete for emergency
support and harsh mining conditions
Jean-Daniel LEMAY1, Marc JOLIN2, Richard GAGNÉ3 and Benoît BISSONNETTE4
1
Research Engineer, Université Laval, Canada
jean-daniel.lemay@gci.ulaval.ca
2Professor, Université Laval, Canada; marc.jolin@gci.ulaval.ca
3Professor, Université de Sherbrooke, Canada
4
Professor, Université Laval, Canada
ABSTRACT
Recent development in the field of cementing materials has brought forward many
nontraditional binder systems. Engineers involved in the fields of emergency
repairs and rapid ground support have been on the lookout for materials thatallow rapid production, placement and, most of all, very rapid strength
development kinetics. One binder system that fits the description is composed ofordinary Portland Cement (OPC), calcium aluminate cement (CAC) and calcium
sulfate ( ). However, this type of binder also sometimes exhibits difficult
workability that limits its use in regular cast in-place concrete. This limitation is
overcome when using dry-mix shotcrete as a placement method, since the contact
between water and cement occurs in the nozzle immediately before placement,
workability problem are avoided. This pneumatic placement method also offersinteresting advantages when considering emergency applications: it makes use of
pre-bagged material, equipment is easy to mobilize and the transport hose caneasily cover hundreds of meters.
As a part of a graduate project at Laval University, 49 different mixes, including
simple, binary and (mainly) ternary blends, were tested. Two majors parameters
were studied, the development of compressive strength and the volumetricstability. The numerous binder compositions tested allowed the selection of astable optimized formulation in regard of early compressive strength andvolumetric stability. Finally, the selected formulation was successfully tested withindustrial dry-mix shotcrete equipment to verify the large-scale placement
feasibility of such a product.
Keywords: emergency support, shotcrete, ultra high early strength
1. INTRODUCTION
Transport and placement methods for concrete have evolved tremendously
throughout history. Although cast-in place concrete is still the most common
placement method, other processes have been developed; let’s simply think of thefirst concrete pump, self-leveling concrete or roller compacter concretes. There is1109

October
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Vietnam
October
2013, Hanoi,
Vietnamalso another concrete placement process developed at the beginning of the lastcentury that has gained global acceptance. First presented to the constructionindustry in 1910 by Carl Akeley (ACI-506.R 2005), shotcrete is nowadays present
everywhere, particularly in the mining and tunneling businesses.
Shotcrete (also know as sprayed concrete in many parts of the world) is aplacement method for concrete. Shotcrete is defined as a mortar or concrete
pneumatically projected at high velocity onto a surface (ACI-506.R 2005). The
high velocity is essential to the process as it ensures an adequate compaction orconsolidation and allows the material to “stick” to the sprayed surface. Without
the proper compaction, quality shotcrete cannot be produce (CP-60 2009).
As any placement methods, different advantages of shotcrete make it more
appropriate in certain situations. With its capacity to stick to vertical and overheadsurfaces, shotcrete need only minimum, if any, formworks. To take full advantageof this specificity, shotcrete is best used in ground supports (tunnel, mine, slope
stabilization, etc.), overhead civil work reparation (bridge deck and parking lower
surface, etc.) and where complex formworks make cast-in place concrete very
expensive (ark type bridge, circular column repairs, etc.).
Shotcrete can be produce using two different processes, the wet-mix and the drymix. The major differences between these processes are the conveying method of
the material through the hose and the location where the water is added to the
mixture.
1.1. Wet-mix shotcrete
In the wet-mix process, all the ingredients are mixed together before being
pumped through the hose. Air is added at the nozzle, through an air-ring, to propel
the material at high velocity onto the surface ensuring sufficient compaction. As
all components are mixed together prior to pumping, wet-mix concrete is usually
delivered on site by standard ready-mix truck and is feed directly into the pump.
With the exception of the set-accelerator, all admixtures are blended before
pumping. When needed, the set-accelerator is added at the nozzle thought a
separate valve by using a special admixture pump. Normal dosage of accelerator
usually range from 2.5 to 6% but dosage of >10% of binder content is sometime
used (Prudêncio Jr 1998). Accelerator dosage has to be carefully planned as it
reduces long-term resistance and durability of concrete (Neville 2008).
1.2. Dry-mix shotcrete
Dry-mix shotcrete is fundamentally different from its wet-mix counter part. In thisprocess, all the solid materials (gravel, sand, cement, additives, fibers, admixtures)are transported through the hose using compressed air. Water is added through awater ring at the nozzle or shortly before depending on the type of nozzle used.
No matter the type of equipment used, the water-binder contact comes only afraction of a second before placement. This particularity enables this process to1110

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bypass workability issues usually associated with the mixing and pumping of
regular concrete. Figure 1 shows a schematic of a typical dry-mix shotcrete set-up.

Figure 1: Typical set-up for dry-mix shotcrete operations
Since materials are introduced in the dry state in the hose, production of dry-mix
shotcrete usually takes advantage of pre-bagged material. This enable easierquality control of the material as the production of such bags is done in acontrolled environment.
1.3. Comparison of both process
Each process have it’s own advantages and inconvenient. Wet-mix shotcrete isusually used only when high volumes of shotcrete are needed due to the important
mobilization needs. On the other hand, while the dry-mix process cannot reach the
production rates of the wet-mix process, its mobilization costs, preparation timeand flexibility are key factors in its selection.
Table 1 : Difference between dry-mix and wet-mix process
Dry-mix process

Wet-mix process

PROS…
Instantaneous adjustment ofshooting consistency

Known w/cm

Delivery hose lighter to move

Rebound and Dust are lower

Start-Stop operations simple

High volume output

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forsupport
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CONS…
Higher reboundHigh volume output sometimes
difficult to manage

Low volume output

Use (and dosage) of accelerator
on site

1.4. Development of new shotcrete
The development of new and alternative binder to Portland cement has opened thefield of cementitious binder to a whole new variety of binder. One of thosebinders exhibiting very promising property is a binder composed of Portland
cement (OPC), calcium aluminate cement (CAC) and calcium sulfate ( )(Lamberet 2005). This type of mixture shows very rapid hardening behavior but is
unfortunately often accompanied with important workability issues. With a pot
life of less than 10 minutes, regular cast-in place application of this type ofconcrete is impossible without the use of numerous chemical admixtures tocontrol set and fluidity. A mean to avoid this type of problem was sought and thisis where dry-mix shotcrete becomes a very interesting process since water isadded only a fraction of a second before impact onto the receiving surface,avoiding workability issues. The validity of such an hypothesis was as part of a
research project at Laval University (Lemay 2013).
2. RESEARCH PROGRAM
The main objective of the project consisted in realizing a conventional dry-mix
shooting session of a special mixture based on a ternary binder using standard
dry-mix equipment and techniques (ACI-506.R 2005; CP-60 2009). To ensure
consistent shotcreting and adequate quality control, the shotcreting took place at
Laval University’s Shotcrete Laboratory. The laboratory is equipped with fullscale shotcreting equipment in an indoor environment that is temperature
controlled. The shotcrete was sprayed using a rotating barrel ALIVA 246 with a38.1 mm (1.5 in) interior diameter hose with the water ring placed 3.0 m (10 ft.)
upstream from the outlet of the nozzle – a.k.a. hydromix nozzle- (Figure 2).

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Figure 2 : Spraying gun (left) and hydromix nozzle (right)
The mixture was shot indoors at an average temperature of 21C (70F). The
Shotcrete Laboratory’s equipment includes an electronic air flow meter, a waterflow meter and a set of electronic scales; the data acquisition system records the
airflow, the water flow and the material used during the spraying operations(Figure 3). The targeted airflow is 4.25 m3/min (180 CFM) at a working air
pressure of 7 bars (105 PSI). The water flow was adjusted (by the operator holding
the nozzle) to what is referred to in the industry as the wettest stable consistency.
The evolution of the water and material flows are used as a quality control point.
Irregular or non-uniform flows lead to the rejection of a mixture.

Figure 3 Schematic of the electronic acquisition system

Ultra rapid
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forsupport
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October
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Vietnam
October
2013, Hanoi,
VietnamPrior to the shotcreting operation, 780 kg of dry shotcrete material was preweighted and pre-blended to allow for the production of the various panels andsamples needed for testing. Table 2 shows the dry proportion of the pre-blended
material.
Table 2 : Dry proportion of sprayed mixture
Ternary Binder
(%)
19.0

Aggregate (%)
Sand

Rock

52.7

28.3

To correctly assess the strength development of the ternary mixture, compressive
strength test were conducted. Early age compressive strength tests (up to 3 hours)
were conducting using beam specimen. These beam specimens are sprayed insteel mold to realize “End-Beam Test” (Heere and Morgan 2002), which is acommon test in the mining industry. Figure 4 shows the set-up used to performthe test and an actual specimen tested.

Figure 4 : “End beam test” apparatus
To evaluate compressive strength after 3 hours, 75 mm (3 in) diameter cores wereextracted from test panel (ASTM 2003; ASTM 2005). Figure 5 shows thedifferent test panels ready for shotcreting in the “rebound chamber” in the
Shotcrete Laboratory.

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Figure 5: Rebound chamber before spraying

3. RESULTS
3.1. Placement and adhesion
The first goal of this shotcreting session is to establish whether the new type ofbinder allows for proper shooting and placement of dry-mix shotcrete. Using thestandard equipment described above, the shotcreting was a success. Indeed, theuse of the hydromix nozzle was efficient in reducing dust emission and noplugging was observed; dust and rebound were similar to those obtained withtraditional dry-mix shotcrete mixture design. Later coring of the test panels
confirms the homogeneity of the in-place material.
Overall, the material shot very well and allow the placement on vertical surfaces
without the need of accelerator; the in-place mixture showed sufficient cohesion
and adhesion to stay in place with more than 125 mm (5 in.) thickness while
presenting rebound losses of approximately 20%.
3.2. Compressive strength
The spraying was successful using standard dry-mix shotcrete equipment.
Particularly, the use of a hydromix nozzle where water is introduced 3 meters (10ft) prior to its delivery through the nozzle allowed the production of homogeneous
good quality shotcrete with no clogging in the equipment. Table 3 presents the
Ultra rapid
strength development
in dry-mix
forsupport
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development
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Vietnamaverage compressive strength obtained using the “End beam test” (figure 4) andusing cores taken from panels.
The results presented in table 3 are actually quite impressive and are deemed asuccess for the mining and tunnelling industry; indeed, “typical” early age andcompressive strength obtained with ordinary Portland cements based mix designand set accelerators are usually around 3 – 4 MPa. Compressive strength over 30
MPa at 3 hours with 28d compressive strength of some 50 MPa are extremely
promising. On the other hand, the 1-hour results also show very interesting
potential for emergency response. Structural damages caused by fire in tunnels orby natural disasters (e.g. flooding or earthquakes) on essential structures could bevery rapidly be alleviated using such a mix design in combination with the drymix shotcrete application method. In fact, although not measured because of its
rapid onset, the setting time of the mixture used is very short (< 10 minutes)
which translates most probably in a few megapascals of compressive strengthwith minutes of its placement.
Obviously, the use of dry mix shotcrete represents an extremely well adapted
method for placing such potent mixtures. Indeed, the fact that all of the drymaterials are conveyed with air through the hose to the nozzle where water isadded gives a very short contact time between the water and the cementing
materials before it is sprayed onto the surface. By using pre-blended bulk bags
that can be stored for long period of time, it becomes easy to have concretematerial ready in case of emergency. Combined with the very simple mobilizationof dry-mix shotcrete and absence of a need for formwork, a fast and reliable
system could be obtained.
Table 3 : Compressive strength
Specimens

Compressive strength, MPa
1h

2h

3h

6h

1j

7j

28j

Prisms

12.9

24.9

29.6

--

--

--

--

Cores

--

--

35.6

47.6

54.6

51.9

52.1

4. CONCLUSION
The objective of this research project was to produce a dry mix shotcrete material
offering a very rapid strength development. This was successfully achieved using
standard shotcreting equipment.
The very rapid hardening provides extremely high early compressive strength (12MPa at 1 hour) showing very interesting potential for emergency response.
Structural damages caused by fire in tunnels or by natural disasters on essential

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structures could be very rapidly alleviated using such a mix design in combination
with the dry-mix shotcrete application method. Along with pre-blended bulk bags
and combined with the ease of mobilization of dry-mix shotcrete equipment, a fastand reliable system could be obtained for rapid “structural emergency” response.
REFERENCES
ACI-506.R (2005). Guide to Shotcrete, ACI International.
ASTM (2003). C 1140 - Standard Pratice for Preparing and Testing Specimensfrom Shotcrete Test Panels.
ASTM (2005). C 1604 - Standard Test Method for Obtaining and Testing Drilled
Cores of Shotcrete.
CP-60, A. (2009). Craftsman Workbook Publication CP-60(09). Farmington Hills,
Michigan, USA.
Heere, R. and D. R. Morgan (2002). Determination of Early-Age Compression
Strenght of Shotcrete. American Shotcrete Association magazine(Spring): 28-31.
Lamberet, S. (2005). Durability of Ternary Binders Based on Portland Cement,
Calcium Aluminate Cement and Calcium Sulfate. PhD., École PolytechniqueFédérale de Lausanne.
Lemay, J.-D. (2013). Développement de béton projeté à ultra-haute résistanceinitiale. M. Sc., Canada.
Neville, A. M. (2008). Properties of Concrete, Pearson Prentice Hall.
Prudêncio Jr, L. R. (1998). Accelerating admixtures for shotcrete. Cement andConcrete Composites 20(2–3): 213-219.

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forsupport
emergency support and harsh
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A study of the behavior of a beam column
joint with complex arrangement ofreinforcing bars by finite element analysis
Liyanto EDDY1 and Kohei NAGAI2
1
Doctoral Student, Department of Civil Engineering
The University of Tokyo, Japan
eddy@iis.u-tokyo.ac.jp
2
Associate Professor, International Center for Urban Safety Engineering
Institute of Industrial Science, the University of Tokyo, Japan
ABSTRACTAs many buildings experienced failures due to the previous earthquake, theperformance requirement of building structures in the seismic design code
becomes more stringent. To satisfy the performance requirement, more
reinforcements of beams and columns are needed. Consequently, at a beamcolumn joint, where reinforcement bars of a beam are anchored into a column,
reinforcement congestion is occurred, causing difficulties during the compaction
and furthermore, resulting a poor quality of construction. To reduce thereinforcement congestion in a beam column joint, a comprehensive study of the
behavior of the beam column joint is needed. However, the behavior of the beamcolumn joint has not been clarified well yet. Many aspects are involved in a
relatively small dimension of a beam column joint, causing a complex stress
distribution, such as material nonlinearity, the bond behavior of the anchorage,
shear, and others, that even some of them are not well understood independently.
In this study, by using a finite element analysis, the behavior of an example of atypical beam column joint of viaduct structures with complex arrangement ofreinforcement bars is studied. In the other hand, the applicability of the finite
element analysis with a complex arrangement of reinforcement bars has not been
investigated. In this study, by using a complex arrangement of reinforcement bars,
the applicability of the finite element analysis in predicting the beam column joint
failure will be studied. Based on the analysis result, typical diagonal cracks ofbeam column joints, observed through the experimental work, can be simulated by
the finite element analysis. However, the behavior of the beam column joint isdifficult to be observed by the finite element analysis, when complicated cracks
occur inside the beam column joint portion.
Keywords: finite element analysis, beam column joint, complex arrangement ofreinforcement bar, anchorage failure.
1. INTRODUCTION
As many buildings experienced failures due to the previous earthquake, theperformance requirement of building structures in the seismic design code1119

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnambecomes more stringent. To satisfy the performance requirement, more
reinforcements of beams and columns are needed. Consequently, at a beamcolumn joint, where reinforcement bars of a beam are anchored into a column,
reinforcement congestion is occurred, causing difficulties during the compaction
and furthermore, resulting a poor quality of construction. To reduce thereinforcement congestion in a beam column joint, a comprehensive study of the
behavior of the beam column joint is needed. However, the behavior of the beamcolumn joint has not been clarified well yet. Many aspects are involved in a
relatively small dimension of a beam column joint, causing a complex stress
distribution, such as material nonlinearity, the bond behavior of the anchorage,
shear, and others, that even some of them are not well understood independently.
In order to study the behavior of beam column joints, particularly with a complex
arrangement of reinforcement bars, there are two alternatives, i.e. experimental
works in laboratories and computational numerical simulations. Throughexperimental works, the real load-displacement relationship can be obtained easily.
However, the behavior of beam column joints with complex arrangement ofreinforcement bars, i.e. how the cracks propagate and how the stresses are
generated, is difficult to observe because of the presence of complicated cracks
and stresses. Thus, the numerical simulation will be a beneficial tool to observe
the behavior of beam column joint with complex arrangement of reinforcement
bars since the internal cracks and the internal strains can be obtained easily as theload changes. By finite element analysis, Salem et al. (2004) simulated well thebond behavior of ribbed reinforcement bars. However, the 3-dimensionalarrangement of reinforcement bars was not modeled and the applicability of thefinite element analysis with a complex arrangement of reinforcement bars has notbeen investigated. In this study, by using a complex arrangement of reinforcement
bars, the applicability of the finite element analysis in predicting the beam column
joint failure will be studied. Therefore, the objective of this study is to study the
behavior of a beam column joint with complex arrangement of reinforcement bars
by finite element analysis.
2. ANALYSIS METHOD
In this study, the simulation was carried out by 3-dimensional finite element
analysis, COM3, developed by The University of Tokyo. In COM3, 3dimensional reinforced concrete model is meshed into some solid elements.
Furthermore, in this study, a beam column joint was meshed into plain concreteelements and steel elements. Details of the material models are discussed in thereferences (Maekawa et.al. (2003)).
3. ANALYSIS OF A BEAM COLUMN JOINT WITH COMPLEXARRANGEMENT OF REINFORCEMENT BARS
3.1 Detailed Analysis
In order to study the behavior of a beam column joint with a complex arrangementof reinforcement bars, the finite element analysis was conducted for a typical1120

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beam column joint of viaduct structures. Since the purpose of this research is to
study the behavior of a beam column joint with a complex arrangement ofreinforcement bars, the dimensions, the reinforcement bars, including bending
portion of the reinforcement bars, and the boundary condition were modeled in an
accurate manner. 3-dimensional model of reinforcement bar was used. However,for the simplification of the analysis model, a rectangular shape of reinforcement
bar is used, with the same area with the circular shape of the actual reinforcement
bar. Furthermore, the dimensions, the reinforcement bars of the beam column
joint, and the boundary condition of the analysis model, will be described below.
3.2 Analysis model
The dimension of the analysis model is shown in Figure 2. Further, the material
properties of the concrete and reinforcement bars are shown in Table 1. 67314
elements are used to model the beam column joint. The size of elements in beamcolumn joint portion is around 1 cm3.
950
1350

400

400

550
400
950

400

Figure 2: Analysis model (Units: mm)
For meshing simplification purpose in the numerical simulation, a rectangularshape of the reinforcement bar was used with the same area with the circularshape of the actual reinforcement bar. In the other hand, spiral stirrups of thecolumn were simplified by increasing the yield strength of the tied stirrups of thecolumn, and tied stirrups of the beam were simplified by enlarging the area of thetied stirrups of the beam. The bending portion of the hooked bar anchorages,
located in beam column joint were modeled in an accurate manner. The
reinforcement bars of the analysis model shown in Figure 3.

4D13
5D25
(a) Beam Re-Bars

360

D16
D13

150

5D25

360

3x100 4x50 100

120(b) Stirrups

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12D16(c) Column Re-bars(d) 3-D Reinforcement Bar of Analysis model

Figure 3: Reinforcement Bars of the Analysis model
3.3 Boundary Condition
Figure 4 shows the detail of the frame loading of the analysis model, which wasused as a typical frame loading in the experimental set-up. Fix condition in all
direction was assumed as the boundary condition at the bottom of the steel frame.
There are 3 hinges that were modeled as the boundary condition. To allow therotation, a pin, located in the middle of the steel plates, is introduced as theconnection between the steel plates (Figure 5). Furthermore, an interface element
is introduced between the pin and the steel plates, with small value of shear
stiffness, so that no shear force is transferred between the steel plates and the pin.
2200
1350

950

265 270 315

725

Hinge

Fix
Figure 4: Detail of Frame Loading of Analysis Model

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Interface(a) PinFigure 5: Detail of Hinge(b) Hinge

Cyclic load of displacement control, pull load and push load alternately, wasapplied to the steel frame, located at the end of the beam, by the displacement
control. In addition, the applied load, pull load and push load, was intended to
examine the behavior of the beam column joint for a moment that tends to open
and close the right angle, respectively. The same load pattern was used in theanalysis model. The load was applied the steel frame which is located at the endof the beam. Figure 6 shows the load pattern of the cyclic load.

Figure 6: Load Pattern of Cyclic Load
4. ANALYSIS RESULT
4.1 Load-Displacement Relationship
Load-displacement relationship of the analysis model is shown in Figure 7 and the
backbone curve of the analysis model is shown in Figure 8. The loaddisplacement relationship is the load and the displacement in which the load wasapplied.

study of theof a beam
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Open

Close
Figure 7: Load-Displacement Relationship of Analysis model
Open

Close
Figure 8: Backbone Curve of Analysis model
Based on the backbone curve of the analysis model, after cracks occur, thestiffness of the beam column joint decreases until the load reaches the maximum
load, both under the opening load and the closing load. Under the opening load,
the maximum load of the beam column joint is 229 kN at the displacement of
1.725 cm. Under the closing load, the maximum load of the beam column joint ishigher than under the opening load, i.e. 370 kN at the displacement of 1.725 cm.
After the load reaches the maximum load, at the displacement of 2.3 cm, the load
capacity of the beam column joint does not decrease significantly under the
opening load, i.e. 227 kN (98% of the maximum load), but the load capacity ofthe beam column joint decreases significantly under the closing load, i.e. 293 kN(80% of the maximum load) because of the anchorage failure of the longitudinalbars of the beam, as discussed later. Furthermore, to observe the failure behaviorof the beam column joint by numerical simulation, the crack pattern of the beamcolumn joint will be described below.

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4.2 Crack Pattern
In this study, the crack pattern obtained by the simulation is described below. The
cracks are not associated with the discrete cracks, but represent the smeared
cracks. Furthermore, the cracks depend on the magnitudes of strains and element
sizes.
4.2.1 Crack Pattern under Closing Load
Figure 9 shows the crack pattern of the analysis model at the displacement of
0.288 cm, 1.15 cm, and 1.75 cm, under the closing load.

1(a) 0.288 cm(b) 1.15 cm
Crack Width:<0.02 cm(c) 1.75 cm
0.02cm-0.3cm

Figure 9: Crack Pattern of the Analysis Model under Closing Load
When the applied load is relatively small, at the displacement of 0.288 cm,
flexural cracks occur outside the bend of the bar anchorages, inside the beamcolumn joint portion. As the load increases, i.e. at the displacement of 1.15 cm,
cracks occur inside the bend of the bar anchorages. Furthermore, diagonal cracks,
which are roughly perpendicular to the bend of the bar anchorages, occur. Before
the load reaches the maximum load, large width of cracks occur at the end of theanchorages (1), and may indicate the beginning of the anchorage failure oflongitudinal bars of beams. At the displacement of the maximum load, i.e. 1.75
cm, more cracks occur inside the bend of the bar anchorages.
To check the applicability of Finite Element Analysis in predicting the beamcolumn joint failure, the crack pattern of the Finite Element Analysis is comparedroughly with typical crack patterns of beam column joints from the previous
experimental work. In this study, the experimental work of beam column joints ofMegget (2003) is used as the comparison. Figure 10 shows the typical crack
patterns of beam column joints from the previous experimental work. Red lines
indicate cracks, formed under the closing load, in the other hand black line
indicated cracks, formed under the opening load. The same tendency of crack
patterns was observed between the finite element analysis and the experimental
work. Diagonal cracks which are roughly perpendicular to the bend of the bar
anchorages also occurred inside the bend of the bar anchorages of beam column
joints of the experimental work, under the closing load. To understand why these
diagonal cracks occur under the closing load, the reason will be described briefly.

study of theof a beam
joint withcomplex arrangement of reinforcing
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jointcolumn
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bars
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Vietnam(a) Joint A(b) Joint 14(c) Joint 7

Figure 10: Crack Pattern of the Experimental Works (Megget (2003))
Figure 11 shows the responses of a beam column joint under the closing load,
resulting moments to close the beam column joint. Forces, generated by the
moments, are introduced into the beam column joint as shown in Figure 11.b. As
the result, diagonal tensile stresses, shear stresses, are formed as shown in Figure
11.c. A diagonal crack occurs when the diagonal tensile stresses exceed the tensile
strength of the concrete (Figure.11.d). The typical diagonal cracks, perpendicular
to the bend of the bar anchorages, verify this behavior.
T

T

Crack
C
T

C

C

(a) Typical Cracks (b) Internal ForcesCT(c) Shear Stress(d) Diagonal Crack

Figure 11: Response of Beam Column Joint under Closing Load
4.2.2 Crack Pattern under Opening Load
Figure 12 shows the crack pattern of the analysis model at the displacement of
0.288 cm, 1.15 cm, and 1.75 cm, under the opening load.

(a) 0.288 cm(b) 1.15 cm
Crack Width:<0.02 cm(c) 1.75 cm
0.02cm-0.3cm

Figure 12: Crack Pattern of the Analysis Model under Opening Load

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When the applied load is relatively small, at the displacement of 0.288 cm,
flexural cracks occur on the re-entrant corner of beam column joint. As the loadincreases, i.e. at the displacement of 1.15 cm, cracks occur inside the bend of thebar anchorages. Furthermore, diagonal cracks, which are roughly perpendicular tothe cracks formed under the closing load, occur. At the displacement of the
maximum load, i.e. 1.75 cm, more cracks occur inside the bend of the bar
anchorages. Based on the experimental result, typical diagonal cracks, which areroughly perpendicular to the cracks formed under the closing load, also occurred
inside the bend of the bar anchorages of beam column joints. To understand why
these diagonal cracks occur under the opening load, the reason will be describedbriefly.
C

Cra
ck

C

C

T

T
C

T

(a) Typical Cracks (b) Internal Forces

T(c) Shear Stress (d) Diagonal Crack

Figure 13: Response of Beam Column Joint under Opening Load
Figure 13 shows the responses of a beam column joint under the opening load,
resulting moments to open the beam column joint. Forces, generated by the
moments, are introduced into the beam column joint as shown in Figure 13.b. As
the result, diagonal tensile stresses, shear stresses, are formed as shown in Figure
13.c. A diagonal crack, which is roughly perpendicular to the cracks formed under
the closing load, occurs when the diagonal tensile stresses exceed the tensile
strength of the concrete (Figure.13.d). The typical diagonal cracks verify thisbehavior.
4.2.3 Crack Pattern at Displacement of 2.3 cm of Closing Load
Figure 14 shows crack pattern at the displacement of 2.3 cm of the closing load.
Complicated cracks occur inside the beam column joint portion of the analysis
model, after loaded by several loads of the opening load and the closing load.
However, the behavior of the beam column joint is difficult to be observed byfinite element analysis, when the complicated cracks occur inside the beamcolumn joint portion.

(a) Cracks of Front’s Surface(b) Cracks of 3-D Model
Crack Width:<0.02 cm
0.02cm-0.3cm
Figure 14: Crack Pattern at Final Step of Load of Analysis Model
A study of the behavior of a beam column joint with complex arrangementof reinforcing bars by finite element analysisNew Technologies for Urban Safety of Mega Cities in Asia 1127

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5. CONCLUSION
Based on the results of the numerical study of the behavior of a beam column
joint with complex arrangement of reinforcement bars by finite element analysis,
the following conclusions are made.
1. Finite element analysis could simulate the behavior of a beam column
joint with complex arrangement of reinforcement bars.
2. When the push load was applied (close-mode), after the load reaches the
maximum load, the load decreases significantly because of the failure of
the anchorages. Diagonal cracks, which are roughly perpendicular to thebend of the bar anchorages, occur. These typical diagonal cracks were also
observed from the experimental results.
3. When the pull load was applied (open-mode), after the load reaches the
maximum load, the load does not decrease significantly as cracks arepropagated inside the beam column-joint portion. Diagonal cracks, which
are roughly perpendicular to the cracks formed under the closing load,
occur. These typical diagonal cracks were also observed from theexperimental results.
4. The behavior of the beam column joint is difficult to be observed by finite
element analysis, after complicated cracks occur inside the beam column
joint portion.
REFERENCES
Yoshitake, K., Ogawa, A., Ogira, D., and Maezono, T., 2012. The Effect of Bond
Behavior of Longitudinal Reinforcement of Beam and Column on Beam Column
Joint. JCI Vol.34, No.2, pp. 541-546. (in Japanese)
Hotta, H., Nishizawa, N., 2012. An Experimental Study on the Effect of the
Position of Longitudinal Reinforcement for Reinforced Concrete Beam-Column
L-shaped Joint. JCI Vol.34, No.2, pp. 282.83-282.88. (in Japanese)
Salem, H., Maekawa, K., 2004. Pre- and Postyield Finite Element Method
Simulation of Bond of Ribbed Reinforcing Bars. Journal of StructuralEngineering 2004.130:671-680.
Maekawa, K., Pimanmasm A., and Okamura, H, 2003. Nonlinear Mechanics ofReinforced Concrete. Spon Press Taylor & Francis Group, London and New York.
Megget, M. 2003. The Seismic Design and Performance of Reinforced Concrete
Beam-Column Knee Joints in Buildings. Earthquake Spectra Vol.19, No.4, pp.
863-895.

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Effects of crystalline admixture
on compressive strength and shrinkage
of concrete with pozzolanic materials
Viet TRAN HUU1, Raktipong SAHAMITMONGKOL2, andSomnuk TANGTERMSIRIKUL3
1
Graduate student, Sirindhorn International Institute of Technology,
Thammasat University. Thailand
E-mail: vietsiit@gmail.com
2
Researcher, Construction and Maintenance Technology Research Center(CONTEC), Sirindhorn International Institute of Technology,
Thammasat University, Thailand
3
Professor, Department of Civil Engineering and Technology (CET),
Sirindhorn International Institute of Technology,
Thammasat University, Thailand

ABSTRACT
Crystalline admixture (CA) is a synthetic cementitious material which contains
reactive silica and some crystalline catalysts. It has been used to improve thewaterproofing and has a potential to improve durability properties of concrete.
The effects of CA on compressive strength, autogenous shrinkage and total
shrinkage of concrete with silica fume (SF) and ground granulated blast-furnace
slag (SG) were investigated and compared in this study. The CA with ratio (0.5,0.6) of total cementitious materials were applied to the specimens with two waterto binder (w/b) ratios 0.4, 0.5 and replacement of SF content (5, 10%) as well as
replacement of SG content (25, 60%) by weight of cement.
It was found that CA tends to increase compressive strength and autogenous
shrinkage and decreasing total shrinkage of all types of concrete to different
extent. The compressive strength at 91 days of almost all types of concrete was
improved by CA. It is expected that the increase of compressive strength should
be related with the crystal formation induced by CA. The CA also increases
autogenous shrinkage of concrete. Both the increase of strength and autogenous
shrinkage imply that the CA may improve the microstructure of concrete by fillingsome pores with crystals.
Although the autogenous shrinkage of concrete was increased by the CA, thetotal shrinkage of the same concrete was drastically reduced. This may be due tothe fact that the CA consumes more water in its reaction and reduces averagepore size so that the evaporation of water to the environment can be limited andretarded.
.
Keywords: Autogenous shrinkage, Compressive strength, Crystalline admixture,
Slag, Silica Fume, Total shrinkage1129

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1. INTRODUCTION
Concrete has been the most widely material used in the construction of civil
infrastructure and industrial facilities worldwide. It was estimated that the present
consumption of concrete in the word is more than 11 billion metric tons per year[1]. Along with this substantial growth of concrete demand, quality and durabilityof concrete have become very important issues.
As the concrete is a composite material produced from aggregates, cement, andother pozzolanic binders mixed with water. In its hardened state, themicrostructure of concrete always consists of pores, capillaries, micro-cracks orvoids. This porous nature of concrete is closely related to its strength as well as
durability (such as shrinkage, chloride resistance, carbonation resistance, etc.) [2].
For decades, mineral additives such as silica fume (SF) and ground granulated
blast-furnace slag (SG) has been added as a partial cement replacement toimprove the engineering properties and performance of concrete [3, 4]. Effects ofthese mineral additives have been widely studied and well-documented [5-7].
Although the application of these mineral additives may beneficially modify the
microstructure of concrete, the porous nature of concrete can only be reduced tosome extent.
Crystalline admixture (CA) is a modern synthetic additive that has been used
for improving waterproofing of concrete. Crystalline admixture contains reactive
silica and some crystalline catalysts that can react with the moisture in concreteand generates a non-soluble, highly resistant crystalline formation throughout the
pores and capillary tracts of concrete [8]. As this crystal formation seals the pores,
it is expected to alter the mechanical properties as well as some durability
properties of concrete.
Incorporating these materials into the concrete mixture not only improves
quality and durability of concrete but also benefits economic and environmental
considerations. The knowledge usage of crystalline admixture on different typesof concrete is still very limited.
The aim of this study is to evaluate how the crystalline admixture cancontribute to properties of concretes containing different binder components. The
effect crystalline admixture on the compressive strength and shrinkage of concrete
is emphasized and experimentally investigated.
2. EXPERIMENTAL PROGRAM
2.1 Materials and mix proportion
The cementitious materials used in this study were ordinary Portland cement
type I (OPC), ground granulated blast-furnace slag (SG) and silica fume (SF).
Chemical compositions and physical properties of these materials are given in
Table 1. Coarse aggregate was crushed limestone with specific gravity of 2.69 anda maximum size of 20 mm. Fine aggregate was river sand with specific gravity
and fineness modulus of 2.60 and 2.13, respectively. A naphthalene-based
superplasticizer (SP) was used to adjust the workability of the concrete.
Concretes with two water/binder ratios (w/b = 0.4, 0.5) were tested. Cementonly concrete was tested and considered as a control concrete. For slag concrete,
SG replacement percentages by weight of total binder content were 25 and 60%.

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Table 1: Properties of cementitious materials
Chemical compositions (%)
Silicon dioxide
Aluminum oxide
Iron oxide
Calcium oxide
Magnesium oxide
Sulfur trioxide
Sodium oxide
Potassium oxide
Physical properiesSpecific gravity (g/cm3)
Loss on ignition (%)
Blaine fineness (cm2/g)

Mix proportion
0.4 OPC
0.4 OPC 0.5
0.4 OPC 0.6
0.5 OPC
0.5 OPC 0.5
0.5 OPC 0.6
0.4 SG 25
0.4 SG 25 0.5
0.4 SG 25 0.6
0.5 SG 25
0.5 SG 25 0.5
0.5 SG 25 0.6
0.4 SG 60
0.4 SG 60 0.5
0.4 SG 60 0.6
0.5 SG 60
0.5 SG 60 0.5
0.5 SG 60 0.6
0.4 SF 5
0.4 SF 5 0.5
0.4 SF 5 0.6
0.5 SF 5
0.5 SF 5 0.5
0.5 SF 5 0.6
0.4 SF 10
0.4 SF 10 0.5
0.4 SF 10 0.6
0.5 SF 10
0.5 SF 10 0.5
0.5 SF 10 0.6

OPC I
20.2
4.70
3.73
63.4
1.37
1.22
0.28

SF
90.64
2.76
0.48
0.71
2.71
0.36
0.85
2.26

SG
34.4
9.0
2.58
44.8
4.43
2.26
0.62
0.5

CA
16.71
3.10
2.27
32.82
1.76
1.27
10.02

3.15
2.72
3430

2.13
3.8
6213

2.68
1.32
4320

2.90
26.68
5540

Table 2: Mix proportion of tested concrete (kg/m3)
Cement Water
SP
SG
SF
CA
382
149
3.82
374
147
3.76
1.88
372
146
3.74
2.25
336
165
3.36
329
162
3.30
1.65
327
161
3.29
1.98
281
144
5.63
93.80
275
142
5.53
92.17
1.84
273
141
5.51
91.85
2.20
248
160
4.95
82.51
242
158
4.88
81.25
1.63
241
157
4.86
81.00
1.94
146
141
5.48
219.17142
138
5.39
215.56
1.80
141
138
5.37
214.83
2.15
129
160
4.84
193.50125
158
4.77
190.60
1.59
125
157
4.75
190.04
1.90
360
145
6.81
18.92
351
142
6.69
18.59 1.86
350
142
6.67
18.53 2.22
316
160
5.59
16.63
309
158
5.89
16.32 1.64
308
157
5.88
16.32 1.96
337
143
6.74
37.45
329
141
6.62
36.80 1.84
328
140
6.60
36.68 2.20
297
159
5.93
32.95
290
156
5.84
32.45 1.62
289
156
5.82
32.35 1.94

Sand
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801
801

Effect of admixture
crystallineon
admixture
on compressive
andofshrinkage
Effects of crystalline
compressive
strength andstrength
shrinkage
concreteof concrete withpozzolanicmaterials.
with pozzolanic materials

Gravel
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096
1096

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For silica fume concrete, SF replacement percentages by weight of total binder
content were 5 and 10%. For all types of concretes, comparative concrete
mixtures with crystalline admixtures (CA) were produced and tested. The
chemical composition of the CA is also provided in Table 1. Two dosages ofcrystalline admixtures (0.5 and 0.6% by weight of total binder content) were
investigated in this study.
Table 2 shows the mix proportions of eighteen concrete mixtures tested in thisstudy. The term ‘OPC I’ represents ordinary Portland cement (Type I), SG
represents ground granulated blast-furnace slag, whereas SF represents silica fume.
An example of description of the mixture designation is as follow: “0.5 SF 5 X
0.5” means the sample which has water to binder ratio of 0.5, silica fume
replacement ratio of 5% and 0.5% of crystalline admixture.
2.2 Test Methods
2.2.1 Compressive strength
The compressive strength was tested in accordance with ASTM C39. Concrete
cylinder specimens with a diameter of 100mm and height of 200 mm were castand demolded at 24 hours after casting. After that, all specimens were sealed byplastic wrap and kept in controlled condition (28 ± 1 oC and RH 50-70%) until theage of testing. The compressive strength was tested at the ages of 7, 28 and 91
days. The universal testing machine (UTM) was applied for loading. The valuesof the compressive strengths are average from three tested samples.
2.2.2 Autogenous shrinkage
Shrinkage was evaluated by investigating the length change of concrete prisms inaccordance with ASTM C157. The size of concrete prism specimens was
75x75x285 mm. Initial lengths of the specimens were measured just after
demoulding at 24 hours after casting. The samples were subsequently doublelayered sealed with plastic wrap and aluminum foil in order to prevent moistureloss to the environment. The loss of water was monitored by measuring the weightof concrete sample. All autogenous shrinkage samples have less than 1% weightloss throughout the test period.
The length of each specimen was measured periodically until the age of 91
days by using length comparator. Free expansion and free shrinkage strain can becalculated by using the following equations (positive value for shrinkage):(1)
ΔL = Li - Lt
6
ε = (ΔL/ Li) x 10
(2)
Where ΔL is the length change of specimen at the time t (mm), Li is the initiallength of specimen (mm), Lt is the length of specimen (mm) at the time t, and ε isthe shrinkage strain.
2.2.3 Total shrinkage
The term ‘total shrinkage’ refers to an absolute volume change of concrete overtime. In this study, it is assumed that the total shrinkage represents a summation of‘autogenous shrinkage’ and ‘drying shrinkage’. All temperature effects are
ignored since the temperature was kept at 28± 1oC throughout the test.

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Concrete prism specimens for total shrinkage measurement were prepared inaccordance with ASTM C 157. After casting, the plastic sheet was used to cover
the specimens to avoid moisture loss to the environment. The specimen were
demoulded at 24 hours after casting and immediately taken for the initial length
measurement. The specimens were subsequently kept in a controlled environment(28 ± 1 oC and RH 50-70%). The length change measurements were conductedperiodically until 91 days.
3. EXPERIMENTAL RESULTS AND DISCUSSION
3.1 Compressive strength
Figure 1 compares the compressive strengths of cement-only concrete and thecement-only concrete with CA. The results indicate that CA can increases thecompressive strength of cement-only concrete at all ages (7, 28, 91 days). By
adding CA, compressive strength of concrete can be increased for approximately
10%. For instance, in the case that the dosage of CA was 0.6% total binder
content and water to binder ratio was 0.4, the CA can increase 28-days and 91days compressive strengths for 10.34% and 12.26%, respectively. While, in thecase that the dosage of CA was 0.6% total binder content and water to binder ratio
was 0.5, the 28-day and 91-day strengths increase for 14.4 and 14.5%,
respectively. More improvement of compressive strength can be expected inconcrete with higher water-to-binder ratio and more dosage of CA. It is also noted
here that, for cement-only, concrete, the strength improvement at 91 days are, inall cases, higher than the strength improvement at 28 days.

w/b = 0.4

w/b = 0.5

Figure 1: Compressive strength of cement-only concrete with/without CA
Figure 2 shows the effects of CA on compressive strength of the slag concrete
Figure 2a and Figure 2b show the results of concrete with 25% and 60% slag
replacement, respectively. It is clearly shown that, when cement is partiallyreplaced by slag (25% or 60%), compressive strengths at 7 and 28 days are
reduced while the compressive strengths at 91 days are increased. This is because
the reaction of slag is slower than cement and requires Ca(OH)2 from cement
hydration to react. The results also show that CA can improve the compressive
strength of slag concrete.
Figure 3 shows the effects of CA on compressive strength of the silica fumeconcrete. Figure 3a and Figure 3b show the results of concrete with 5% and 10%
silica fume replacement, respectively. The results show that the effect of CA on
Effect of admixture
crystallineon
admixture
on compressive
andofshrinkage
Effects of crystalline
compressive
strength andstrength
shrinkage
concreteof concrete withpozzolanicmaterials.
with pozzolanic materials1133

October
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Hanoi,Hanoi,
Vietnam0ctober
Vietnamthe compressive strength of silica fume concrete at the age of 7 days and 28 days
is not so good and reductions of compressive strength can be observed in somecases. However, the CA can increase the compressive strength of all silica fumeconcretes at 91 days. The deficiency of the CA during the early age may be due tovery high reactivity of silica fume which may considerably consume Ca(OH)2 inthe early age period. The CA thus cannot react well in such period.
In spite of slight difference in strength development characteristics of all typeconcrete, it is proved that the CA can improve long-term strengths of all concrete.
The strength improvement was found to be higher in older concrete. This result
also suggests that the crystal formed by CA contributes as a permanent componentof the cementitious microstructure system.

Figure 2: Compressive strength of slag concrete with/without CA

Figure 3: Compressive strength of silica fume concrete with/without CA
3.2 Autogenous Shrinkage
The effect of CA on autogenous shrinkage of cement-only concrete is shown in
Figure 4. The autogenous shrinkage at both w/b ratios 0.4 and 0.5 was increasedby the addition of CA (Figure 4a and Figure 4b). In this case, the autogenous
shrinkage may increase because the formation of crystals by CA changes pore
structure and also consumes free water. The presence of CA in the system thusincreases the self-desiccation.
Figure 5 shows the autogenous shrinkage of slag concrete. For concrete with
25% slag replacement (Figure 5a and Figure 5b), in the early age period, theautogenous shrinkage of slag concrete was smaller than that of cement-only
concrete. However, at longer period, concrete with 25% slag has clearly more

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autogenous shrinkage. For concrete with 60% slag replacement (Figure 5c andFigure 5d), an early-age expansion can be observed and the final autogenous
shrinkage is remarkably reduced. The early-age expansion may be induced by theformation of ettrigite since the slag contains higher content of sulfate (see Table1). For all slag concrete mixtures, adding CA results in relatively higher
autogenous shrinkage.

Figure 4: Autogenous shrinkage of cement only - concrete with/without CA

Figure 5: Autogenous shrinkage of slag concrete with/without CA
Figure 6 shows the autogenous shrinkage of silica fume concrete. When silica
fume is added to concrete the autogenous shrinkage of concrete is drasticallyincreased. For the silica fume concrete with w/b = 0.4 (Figure 6a and Figure 6c),the autogenous shrinkages at 7 days were approximately double of those of
cement-only concrete. This is due to a high reactivity and reaction rate of silica
fume. As the rate of reaction is accelerated, the autogenous shrinkage became

Effect of admixture
crystallineon
admixture
on compressive
andofshrinkage
Effects of crystalline
compressive
strength andstrength
shrinkage
concreteof concrete withpozzolanicmaterials.
with pozzolanic materials

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October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamlarger. Adding CA into silica fume concrete additionally increase the autonomous
shrinkage.
The test results clearly show that the CA increases the autogenous shrinkage of
all types of concretes. The increase of autogenous shrinkage should be related tothe modification of microstructure by the crystal formation. Although the higher
value autogenous shrinkage indicates higher risk of shrinkage crack. It, at thesame time, implies that the microstructure of concrete became denser by theincorporation of CA. Furthermore, the risk of shrinkage crack should be evaluatedby considering the total shrinkage not merely the autogenous shrinkage.

Figure 6: Autogenous shrinkage of silica fume concrete with/without CA
3.3 Total shrinkage
Figure 7 shows the total shrinkage of cement-only concrete. Higher water-tobinder ratio (w/b) results in higher total shrinkage although the autogenous
shrinkage is reduced (see Figure 4). This is because the concrete with higher watercontent, in same drying condition, encounter more evaporation of free water andmore drying shrinkage.
Figure 8 and Figure 9 shows the total shrinkage of slag concrete (Figure 8a andFigure 8b) and silica fume concrete (Figure 9a and Figure 9b), respectively. In
this experiment, it was found that the partial replacement of cement by slag orsilica fume can reduce the total shrinkage to a certain extent although the
autogenous shrinkage was found to be larger (see Figure 5 and Figure 6).
This is probably related to the small size of test concrete prisms and their highsurface area. With this high surface area to total volume (S/V), the drying

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shrinkage dominates the total shrinkage behavior. It is noted here that thecontribution from drying shrinkage should be proportionally lower in the case of
the real concrete structural element.

Figure 7: Total shrinkage of cement only - concrete with/without CA

Figure 8: Total shrinkage of slag concrete with/without CA

Figure 9: Total shrinkage of silica fume concrete with/without CA
The results of all types of concrete also demonstrate that the addition of CA
into concrete reduces the total shrinkage (see Figures 7, 8, and 9) although it wasreported to induce higher autogenous shrinkage (see Figures 4, 5, and 6). It is
possible that CA consumes free water in its reaction and reduces evaporable watercontent. At the same time, the average pore size is expected to be reduced by the
Effect of admixture
crystallineon
admixture
on compressive
andofshrinkage
Effects of crystalline
compressive
strength andstrength
shrinkage
concreteof concrete withpozzolanicmaterials.
with pozzolanic materials

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October
2013, 2013,
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Vietnam0ctober
Vietnamcrystal formation. This smaller pore can retard the evaporation of free water toenvironment. As a result, the drying shrinkage can be reduced when CA is added.
Figures 10, 11, and 12 show the effects of CA on the drying shrinkage of
cement-only concrete, slag concrete, and silica fume concrete, respectively. The
drying shrinkage was calculated by subtracting the total shrinkage with the
autogenous shrinkage of the same mix. The results clearly show the drying
shrinkage of all types of concrete can be drastically reduced by the incorporationof CA. Especially, in the case of concrete with 10% silica fume replacement, theCA can reduce drying shrinkage remarkably low (lower than 90 ).

Figure 10: Drying shrinkage of cement only - concrete with/without CA

Figure 11: Drying shrinkage of slag concrete with/without CA

Figure 12: Drying shrinkage of silica fume concrete with/without CA

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4. CONCLUSIONS•••

Crystalline admixture (CA) increases compressive strength, especially at
long-term of all types of concrete (cement-only concrete, slag concrete,and silica fume concrete).
The increase of strength is more at long-term. This suggests that the
improvement by CA is permanent.
Although CA increased the autogenous shrinkage of concrete, the total
shrinkage was favorably reduced. This is related to ability of CA to reduce
the evaporation of free water from the concrete specimens.

REFERENCES[1] Mehta, P.K., Monteiro. Paulo J.M, 2006. Concrete, Microstructure, properties,
and Materials, 3rd Edition.
[2] Tangtermsirikul, S., 2003. Durability and Mix design of concrete, 1st Edition.
[3] Malhotra, V.M., and Mehta, P.K., 1996. Pozzolanic and cementitious
materials, Advances in Concrete Technology, Gordon and Breach, London.
[4] K.E. Hassan, J.G. Cabrera, R.S. Maliehe, 2000. The effect of mineraladmixtures on the properties of high-performance concrete, Cement and Concrete
Composites, 267-271.
[5] Bouikni, A, Swarmy, R.N., and Bali, A., 2009. Durability properties ofconcrete containing 50% and 65% slag, Construction and Building Materials,
2836-2845.
[6] Lee, K.M., Lee, H.K., Lee, S.H., and Kim, G.Y., 2006. Autogenous shrinkage
of concrete containing granuated blast-furnace slag, Cement and Concrete
Research, 1279-1285.
[7] Zhang, M.H., Tam, C.T., Leow, M.P., 2003. Effect of water-to-cementitious
materials ratio and silica fume on the autogenous shrinkage of concrete, Cement
and Concrete Research, 1687-1694.
[8] Yodmalai, D., Sahamitmongkol, R., Tangtermsirikul, S., Lawtrakul, L., 2010.
Water sorptivity, water permeability, autogenous shrinkage, and compressive
strength of concrete with crystalline materials , 15th National Convention on
Civil Engineering, Ubon Ratchathani, Thailand.

Effect of admixture
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admixture
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compressive
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shrinkage
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Effect of heating and re-curing
on crack characteristics in cement paste
Yuto HARAGUCHI1, Michael HENRY2, Ivan Sandi DARMA3,
and Takafumi SUGIYAMA4
1
Master student, Division of Field Engineering for the Environment,
Graduate School of Engineering, Hokkaido University, Japanknmrhtkemsn@gmail.com
2
Assistant professor, Division of Field Engineering for the Environment,
Faculty of Engineering, Hokkaido University, Japan3
Ph.D. student, Division of Field Engineering for the Environment,
Graduate School of Engineering, Hokkaido University, Japan
4
Professor, Division of Field Engineering for the Environment,
Faculty of Engineering, Hokkaido University, Japan
ABSTRACT
After fire, concrete performance degrades due to dehydration of the cement paste,
which leads to coarsening of microstructure and the formation of cracks. Healingof cracks has been observed under water re-curing, and these may have a large
influence on the recovery of concrete performance, but it is necessary to better
understand the effects of heating and subsequent re-curing on crack
characteristics. In this research, the changes in microstructure and cracks due toheating and re-curing were investigated by applying X-ray CT and image analysis
techniques, which enable non-destructive examination of the internal
microstructure of a material. Results showed that, in the cement paste specimen,
radial cracks formed during heating due to shrinkage by dehydration. Under
water re-curing, these cracks grew larger and new cracks formed due toexpansion by rehydration. The growth of the cracks in the cement paste underwater re-curing may be due to the rehydration of calcium oxide into calcium
hydroxide under water supply which led to expansion of the specimen.
Keywords: fire damage, re-curing, microstructure, crack recovery, rehydration,
repair
1. INTRODUCTION
After fire, concrete performance degrades due to dehydration and cracks causedby shrinking, so it is necessary to restore performance to the same state as before
the fire for resuming use of concrete structure. Restoring performance generally
involves repair operations, including demolition of the damaged concrete, butthese require extensive labor and time which may contribute to an increased
environmental impact.

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October
2013, Hanoi,
VietnamSome past research has reported that concrete performance can be recovered by
re-curing the fire-damaged concrete in water. This leads to self-healing of cracks
and decrease in air voids due to rehydration of cement hydrates (Suzuki et al.,2010; Henry et al., 2011). The healing of cracks under re-curing may have a large
influence on the recovery of concrete performance, but crack formation andrecovery under fire loading and re-curing have not been studied in depth.
Therefore, in this research the formation and change in cracks after heating andre-curing was investigated using X-ray CT, which can non-destructively examine
the internal microstructure of a material.
2. EXPERIMENTAL PROCEDURE
2.1 Overview
An overview of the experimental flow is shown in Figure 1. High-strength cement
paste with a W/C of 30% was made using ordinary Portland cement, andspecimens were cured in water for 13 weeks. After curing, specimens were heatedat 600ºC in an electric furnace for 1 hour. After heating, specimens were re-cured
in water for up to 13 weeks. In this research, two experiments were carried out: Xray CT and TG/DTA (Thermogravimetry Differential Thermal Analysis).
Specimens were examined before heating, after heating and after 1 (TG/DTA
only), 4 and 13 weeks water re-curing.

Figure 1: Experimental flow
2.2 Specimens
Two types of specimens were prepared: cylinders (100×200 mm) and beams(40×40×160 mm). As shown in Figure 2, after curing for 4 weeks cores 20 mm indiameter were extracted from the cylinder specimens and cut to a length of 20 mm.
The beam specimens were also sliced (40×40×2 mm) at the same time, and thesmall test specimens were returned to the water for 9 more weeks.
2.3 Heating and re-curing
After 13 weeks of curing, the test specimens were exposed to high temperatures inan electric furnace. The heating curve and electric furnace picture are shown
Figure 3. The rate of heat increase was set at 10ºC per minute and the target
temperature of 600ºC was held for 1 hour. After heating, specimens were cooled
naturally in the air for 1 hour then re-cured in water of at 20ºC for up to 13 weeks.

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Figure 2: Flow of specimen preparation and curing

Figure 3: Heating curve (left) and specimen heating conditions (right)
2.4 Image capture using X-ray CT
As summarized by Promentilla and Sugiyama (2010) and Landis and Keane(2010), the concept of X-ray microtomography is similar to that of Computed
Axial Tomography (CAT or CT) scans in the medical field, in which a threedimensional (3D) digital image is reconstructed from a series of two-dimensional(2D) images or “slices.” Each voxel (3D pixel) within the 3D digital image has an
associated X-ray absorption value which can be correlated to material density, andthus the internal structure can be determined based on the arrangement of thevoxels in a 3D space.
The setup for acquiring the X-ray CT images is shown in Figure 4 and the detailsof the X-ray CT specimen are shown in Figure 5. Image acquisition in thespecimens occurred in the illustrated focus area, which was approximately 11 mm
in height, 20 mm in diameter, and roughly centered on the specimen. In this area,
351 slices of 33 microns thick were obtained. Each slice was 1024 x 1024 pixels
in size, with each pixel 20 x 20 microns, for a voxel size of 20 x 20 x 33 microns.

Effect of heating and re-curing on crack characteristics in cement paste
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October
2013, Hanoi,
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360° rotation

Image intensifier &CCD camera

ComputerMicrofocus
X-ray tube
Cone beam

Emission

Absorption

Detection

Re-construction

Figure 4: X-ray CT system setup for image capture
X-ray CT specimen

Focus
area
11 mm

Series of slices

Reconstructed
3D volume

Slice

20 mm

351 slices

Figure 5: Details of the X-ray CT specimen and 3D image reconstruction
2.5 Chemical analysis
In this research, TG/DTA (Thermogravimetry Differential Thermal Analysis) was
carried to analyze the chemical composition. TG measures the weight change ofthe heated sample, while DTA measures the temperature gap between the sample
and a reference material (alumina is used as the reference). In this research, theanalysis conditions were a heating rate of 10ºC/minute and a target temperature of
100ºC.
3. RESULTS AND DISCUSSION
3.1 X-ray CT images
Figure 6 shows the cross-sectional images of the cement paste specimen at various
heights (measured from the bottom of the specimen) before and after heating andafter re-curing. After heating, it is difficult to visually identify the cracks, but they
can be observed to occur radially due to shrinkage caused by heating. After water
re-curing for 4 weeks, the crack width appeared to increase; in addition, some new
cracks formed which appeared to bridge between crack tips inside the specimen.
From 4 to 13 weeks, however, the crack widths appeared to be mostly unchanged.
From these images it is difficult to fully capture the cracking behavior under
heating and re-curing so, quantitative evaluation is necessary.

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H = 12 mm

H = 17 mm

13 weeks re-curing

4 weeks re-curing

After heating

Before heating

H = 7 mmFigure 6: Slice images of the cement paste specimen
3.2 Crack width analysis method and results
In order to quantitatively evaluate the change in crack characteristics due to water
re-curing, some cracks were selected and their widths measured. The method formeasuring crack width is illustrated in Figure 7. Segments which intersected aselected cracks were drawn on the CT image at various depths from the specimen
surface, and the width were measured based on the extracted CT value
distribution along the segment.
The results for two cracks are shown in Figure 8. After heating, the cracks shapes
are such that the width becomes smaller further away from the surface. After 4
weeks re-curing, the crack width increased between 10 to 70 μm. For Crack #1,
Effect of heating and re-curing on crack characteristics in cement paste
Effect of heating and re-curing on crack characteristics in cement paste

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October
2013, Hanoi,
Vietnamthe width increased less at the surface and more at away from the surface. For
Crack #2, the width appeared to increase evenly along the whole length. After 13
weeks re-curing, the crack width generally increased from 4 weeks, but did
decrease slightly at a few points. Particularly in Crack #1, the change in crack
width from 4 to 13 weeks was greater near the surface but much less deeper along
the crack. Overall, when comparing the crack widths after heating and after 13
weeks water re-curing, the crack widths increased between 25 to 125 μm.

Figure 7: Crack width analysis method

Figure 8: Crack width analysis results (left) and selected cracks (right)
3.3 Reconstruction of 3D crack network
The connected cracks and air voids were extracted used a segmentation method toseparate solids and voids and convert the slice to a binary (black and white) image.
After carrying out the segmentation for all slices, a 3D reconstruction of the crack
network (after 4 weeks water re-curing) could be prepared by compiling the slice
stack. The result is shown in Figure 9. It can be clearly seen that cracks propagate
radially inwards from the specimen surface and propagate both vertically andhorizontally. Some cracks also intersect air voids in the specimen.

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Figure 9: 3D crack network after 4 weeks water re-curing
3.4 Chemical analysis results
In order to understand why the crack widths increased, chemical analysis was
conducted. Under exposure to temperatures between 400 and 500ºC, Ca(OH)2 in
concrete decomposes to calcium oxide (CaO) and water (H2O). The reverse
reaction occurs during rehydration (CaO changes to Ca(OH)2). It has beenreported that rehydration can cause expansion in a specimen due to the larger
volumetric size of CaO compared to Ca(OH)2 (Hewlett, 1998). Therefore, theanalysis focused on the change in calcium hydroxide (Ca(OH) 2).
Figure 10 shows the TG/DTA test results, where the change in calcium hydroxide
is reported as a percentage of the pre-heating condition. After heating, the amountof calcium hydroxide decreased by 60%, but after 1 week of water re-curing theamount returned to a similar value as before heating. However, between 1 and 13
weeks of water re-curing little change was observed. Therefore, rehydration of
calcium hydroxide appeared to finish in just one week of water re-curing.

Figure 10: Change in calcium hydroxide(as a percent of the pre-heating amount) due to heating and re-curing

Effect of heating and re-curing on crack characteristics in cement paste
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As mentioned previously, it has been reported that rehydration can cause
expansion in a specimen, which would lead to an increase in crack width andgrowth of new cracks. Based on the obtained chemical analysis results, as well as
observations of the cracking pattern, the recovery of Ca(OH)2 under water recuring is believed to be the cause of the increase in cracks width and growth of
new cracks as seen in the X-ray CT images and crack width analysis results.
4. CONCLUSION
The objective of this research was to non-destructively investigate the changes incracks in cement paste material due to heating and re-curing by applying X-ray
CT and image analysis techniques. After heating, cracks occurred radially but
were difficult to observe. Through image analysis, it was shown that re-curing
lead to an increase in crack width of 25 to 125 μm, along with the formation of
new cracks which bridged between radial cracks inside the specimen. The
formation of these cracks is believed to be caused by expansion due to therehydration of CaO into Ca(OH)2. From 4 weeks to 13 weeks, cracks appeared toremain mostly unchanged and there was little change in the mass of Ca(OH)2.
This study has several limitations which need to be addressed in the future. First,
cracks were only examined in 2D images but they occurred in 3D space. Second,the change in other cement hydrates such as such as C-S-H need to be examined
to better clarify the re-curing mechanism. Finally, the observed changes in thecrack space and microstructure need to be related to changes in mechanicalproperties such as strength or durability.
ACKNOWLEDGMENT
This research was partially supported by the Japan Society for the Promotion of
Science (Scientific Research B, no. 23360187).
REFERENCES
Hewlett, P.C., 1998. Lea’s Chemistry of Cement and Concrete, 4th Ed., Elsevier,Oxford.
Landis, E.N., Keane, D.T., 2010. X-ray microtomography. Materials
Characterization Vol. 61, pp. 1305-1316.
Henry, M., Suzuki, M., Kato, Y., 2011. Behavior of fire-damaged mortar undervariable re-curing conditions. ACI Materials Journal, 108(3), pp. 281-289
Promentilla, M.A.B., Sugiyama, T., 2010. X-ray microtomography of mortars
exposed to freezing-thawing action, Journal of Advanced Concrete Technology
Vol. 8 No. 2, pp. 97-111.
Suzuki, M., Henry, M., Kato, Y., Katsuki, F., 2010. Influence of re-curing on
physio-chemical properties of mortar exposed to fire. Cement Science andConcrete Technology No. 63, pp. 148-154. (in Japanese)

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Introduction of CAESAR’s research activity
utilizing decommissioned bridge in Japan
Akiko HIROE1, Hidetaka HOMMA2, and Yoshitomi KIMURA3
Researcher, Bridge and Structural Engineering Research Group,
CAESAR, PWRI, Japanhiroe@pwri.ge.jp
2
Senior Researcher, Bridge and Structural Engineering Research Group, CAESAR,PWRI, Japan
3
Chief Researcher, Bridge and Structural Engineering Research Group,
CAESAR, PWRI, Japan
1

ABSTRACTIn Japan, approximately 50% of the bridges will become more than 50 years old
in next decade and numerous bridges have been damaged while they are inservice. Needs for inspection, assessment, repair and rehabilitation of existingbridges are rapidly increasing. Center for Advanced Engineering Structural
Assessment and Research (CAESAR) was established as one of the organizationof Public Works Research Institute (PWRI) in Japan to tackle such current
infrastructural issue. For safe and sustainable use, CAESAR focuses on a“clinical study” which utilizes decommissioned bridges. The final goal of thestudy is to establish evaluation methods for deteriorated bridges. We introduce
current condition of Japanese highway bridges and its management in this paper.
Concerning concrete bridges, examples of defects of bridges and CAESAR’s
research activity utilizing decommissioned bridges are also described.
Keywords: decommissioned bridge, defect of bridge, bridge maintenance

1. INTRODUCTION
Center for Advanced Engineering Structural Assessment and Research(CAESAR) was established in April, 2008 as one of four research institutes andcenters in Public Works Research Institute (PWRI). At that time, an issue of aging
infrastructure had become apparent as represented by the collapse of the bridge in
Minneapolis, Minnesota, U.S., August 2007. In Japan, a fracture of a truss
member covered in concrete deck was found in Kiso River Oh-hashi Bridge in thesame period. CAESAR tackles such infrastructural issues related to bridges. Oneof the pillars of its research activity is a “clinical study.” Similar to the medical
research, it requires accumulation of cases of defects and specimens of damaged
bridges. As a part of clinical study, CAESAR conducts studies utilizing
decommissioned bridges or its components.

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2. CURRENT CONDITION OF HIGHWAY BRIDGES IN JAPAN
Figure 1 shows the number of highway bridges in Japan sharply increased from1950s to 1970s. This period was Japan’s high economic growth period and during
the time, early enrichment of infrastructure was desired. Since bridges wereintensively constructed in a short period, the percentage of aging bridges increases
rapidly after 2000. Figure 2 portrays that the percentage of highway bridges older
than 50 years. In both figures, bridges longer than 15 m are counted. The
statistical data indicate that, by 2031, 53% of Japan’s highway bridges will beolder than 50 years, where the total number of existing bridges is approximately
157,000 as of April 1, 2010.
Figure 3 shows the percentage of bridges by damage level on designated national
highway. The data was obtained from inspection of bridges longer than 2 m.
From the figure, it is found that about 40% of bridges have damages that require
immediate remedial action.

Figure 1: Transition of the Construction Number of Highway Bridges
by Fiscal Year of in Japan

Figure 2: Percentage of Bridges Aged 50 Years or Over(bridge length of 15 m or more)

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Remedial Action Criterion
Level

Remedial Action

A

No or negligible damage
No remedial action is required

B

Depending on situation

C

Immediate action is required

E1
E2
M
S

Urgent action is required from theview point of structural safety
Urgent action is required by otherreasonAs a part of ordinary maintenancework
Detailed survey is required

Figure 3: Percentage of Bridges by Damage Level on Designated National
Highway (bridge length of 2 m or more)

3. HIGHWAY BRIDGES INSPECTION IN JAPAN
Figure 4 shows the flowchart ofJapanese highway bridges inspection.
In 2004, revised inspection manual for
bridge was released by Ministry ofLand, Infrastructure, Transport andTourism (MLIT), which is promoting
preventive maintenance and long
duration of infrastructures. In thisrevision, some contents are modified
considerably. The first point is theintroduction of the initial inspection. It
is conducted within 2 years fromconstruction to find out initial
deficiencies such as bulging, peeling ofpaint, leakage or ponding bymalfunction of drainage structure orwater proof system, initial crack on
concrete and so on. The second point is
the shortening of the periodic
inspection interval. The pre-manual
recommended periodic inspections
once in 10 years but the revised manual
Figure 4: Flowchart of Highway
shortens them to once in 5 years in
Bridges Inspection in Japanorder to prevent from risks to missindications of deterioration and rapid progress of deficiencies. The visualinspection is conducted every 5 years and each part composing bridge is inspectedby a proximate observation. Highway operators make a chart for each bridge
based on the results of inspections. Bridges are categorized with the remedial

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Vietnamaction criterion, which is on right side of Figure 3. If the bridge is given C, E1 orE2, it needs some remedial action immediately.

4. RECENT CASES OF BRIDGE DAMAGE
Figure 4 shows the percentage of bridges by
their materials. In Japan, bridges are mainly
constructed with steel and concrete. According
to the figure, the percentage of prestressed
concrete bridges is almost equal to that of steel
bridges, and 58 % of bridges are constructedwith concrete. It reveals that concrete is theone of popular material for bridge constructionin Japan. Therefore, some recent cases ofdamage of bridges in Japan are reported withfocusing on concrete bridge in this section.
Figure 4: Percentage of Bridges
by materials in Japan
4.1 Chloride-Induced Deterioration
Chloride-induced deterioration is one of the major issues in the maintenance ofconcrete bridges. It occurs in coastal area, especially in Okinawa, which is thesouthernmost part of Japan and northern Japan sea side. That is because windbrings salinity from sea; Okinawa is frequently struck by typhoons every year andnorthern Japan sea side is hit by northwest seasonal wind. The cold districts arealso the area where chloride-induced deterioration occurs because sometimes
antifreezing agent including chloride is used on bridges.
Figure 5 shows the collapse of concrete bridge in Okinawa in 2010. Before
collapse, many rebars had been already fractured because of the corrosion inducedby chloride. This bridge was closed to traffic when it collapsed, so that it did notcause injury. Other bridges’ chloride-induced deterioration is on Figure 6.

(a) before collapse(b) after collapse
Figure 5: Collapsed Concrete Bridge in Okinawa

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ICUS Report 73(a) falling off of concrete(b) crack by expansion pressureof corroded PC cables
Figure 6: Chloride-Induced Deterioration

4.2 Alkali-Silica Reaction (ASR)
Some aggregate in concrete causes a chemical reaction with alkali despite insideof concrete being alkaline environment. Substance that results from a chemical
reaction makes its volume increase because of the water absorption and cracks
occur on a surface of concrete. In some cases of ASR, breakages of rebars becauseof the expanding pressure of concrete were found. This may have a significant
effect against structural integrity.
Figure 7 shows cracks induced by ASR. Map crack appears on the structure with
non-directional binding, e.g. structure which has a small amount of rebar, and ahorizontal crack found on the structure with strong binding, e.g. structure which
has a large amount of rebar or prestress. For the prestressed structures suffering
ASR, it is known that longitudinal cracks along prestressing direction may appear.

(a) map crack on pier(b) horizontal crack on precast
hollow girder (PC)
Figure 7: Cracks Occurred by ASR

5. RECENT CASES OF CLINICAL STUDY
To encouraging preventive maintenance and long duration of bridges, theestablishment of evaluation method for aging and damaged bridges is essential.
“Clinical study” is conducted with decommissioned bridges by CAESAR in orderto reveal behaviors of deteriorated bridges, to detect the internal deficiencies ofbridges, to assess non-destructive testing (NDT) technologies, and so on.
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CAESAR wrestles with the problems of aging bridges by it. Some cases ofclinical study are introduced in this section.
5.1 Loading Test
It is very important to assess the remaining strength of deteriorated bridges when
the operator judges its serviceability, timing of repair or demolition. Although it isdesirable to conduct full scale loading test using whole bridge, it is quite
expensive and subjects to restriction of loading facilities. Therefore, CAESAR
samples members of bridges as large as possible and conducts loading test.
Figure 8 shows Kuratani Bridge. It was 2-span simply-supported reinforced
concrete slab bridge constructed in 1959. The bridge was located on near the coastline of western Japan and suffered chloride induced deterioration. When theoperator decided to demolish the bridge in 2010,
large area of cover concrete on the bottom surfaceof the deck was already separated or fell off
because of the expanding pressure of corroded
rebars (Figure 9). Loading test was conducted withsampled bridge slab deck (Figure 10). From the test,
the correlation between the ultimate strength andthe area loss of rebars were revealed as Figure 11
shows.
Figure 8: Kuratani Bridge before
Demolition

Figure 9: Corroded Rebars andSeparated Concrete Cover

Figure 10: Loading Test using Sampled
Bridge Slab120

Area of Intact Rebar

Bending Moment（kN･m）

100

Averaged Area of Corroded Rebars

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Minimum Area of Corroded Rebars

40
20
0
0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

Curvatureφ（1/m）

Figure 11: Curvature and Bending Moment

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5.2 Anatomical Study
Anatomical study is done for detecting internal deficiencies of bridge members,
such as corrosion of steel member inside concrete, chlorine content in core
specimens, condition of cracks, or insufficient grouting in post tension prestressed
concrete. Through anatomical study using decommissioned bridge members, it isexpected to accumulate the knowledge regarding such issues.
Tsuha Bridge (Figure 5) was simply-supported reinforced concrete girder bridge
constructed 1931 in Okinawa and collapsed in 2010 mainly because of chloride
induced deterioration. As mentioned in 4.1, Okinawa is one of the harsh places forconcrete bridges. It was thought that the concrete had large amount of salt insidefrom the beginning of its service when the quality control was not well established.
CAESAR sampled some portions of girders (Figure 12) and conducted anatomical
study. As Figure 13 shows, rebars under cover concrete corroded less despitewhile the exposed rebars lost almost all their cross section. Figure 14 and Figure
15 reveals that the chloride ion concentration is higher than the marginal
concentration of corrosion occurrence at the main reinforcements or stirrups.
However, deep portion of concrete has not much chloride ion. That indicates thatthe amount of initial salt in the concrete might be carefully controlled.

ExposedFigure 12: Sampled girder of Tsuha
BridgeUnder Cover

Figure 13: Diminishment of Rebar

Figure 14: Chloride Ion Vertical Distribution in the Girder

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October
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VietnamFigure 15: Chloride Ion Horizontal Distribution in the Girder
5.3 Non-Destructive Testing (NDT)The NDT is demanded to inspect the invisible portions, such as the inside ofconcrete, without causing damage to the bridge. The development of NDTtechnologies has been progressing and many kinds of NDT devices have been
produced. Decommissioned bridges with various deficiencies are good fields toevaluate performance of NDT devices.
X-Ray Tomography is one of the wellknown NDT technologies. Figure 16
shows the X-ray generator whose energy
output is 300keV. It is utilized in bridge
inspections. X-ray images of thedecommissioned bridge were taken by
this device. The results are shown in
Figure 17. It is possible to discriminate
rebars, PC cables and voids in sheathes.
Figure 16: X-ray Generator (300keV)(a) Thickness: 400mm(b) Thickness: 160mm (Irradiation time: 3 min)(Irradiation time: 60 min)Figure 17: X-ray Image of Decommissioned Bridge

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However, the image of the 400 mm thickness area is unclear compared with thoseof 160 mm thickness area. In addition, thicker part need much more time than
thinner part. It reveals that more improvement is necessary to get clearer image by
X-ray.
As Figure 18 shows, other kinds of NDT devices are also evaluated concerning
their performance with utilizing decommissioned bridges or deteriorated bridge.

(a) Electromagnetic Radar(b) Ultrasonic
Figure 18: Examples of NDT Devices Evaluation

6. CONCLUSION
The bridges in Japan are now facing their aging and deterioration. Therefore, themaintenance of the bridges is essential to sustain society of Japan. Developmentof inspection methods and repair methods for bridges is expected. We, CAESAR,
tackle to those issues with our research activities. The clinical study utilizing
decommissioned bridges is just a case study now and still there is difficulty toreveal the comprehensive method. Thus, CAESAR will continue the accumulationof cases and analyze them in order to summarize practical manuals or
specifications for more rational maintenance of bridges.

REFERENCES
Hanai, T., Ohishi, R., Kuwabara, T., Hoshikuma, J., and Murakoshi, J., 2011.
Research Activity Utilizing Decommissioned Bridge. Proceedings of the 2011
International Forum on Bridge Engineering, 203-223
Tamakoshi, T., Okubo, M., and Yokoi, Y., 2012. Annual report of basic data onroad structures in FY 2011. Technical Note of National Institute for Land andInfrastructure Management, No.693, Japan, (in Japanese)

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Performance of different sacrificial anodematerials on corrosion protectionof reinforcing steel
Pakawat SANCHAROEN1, Aris MAHASIRIPANA2
and Somnuk TANGTERMSIRIKUL3
1
Researcher, Construction and Maintenance Technology Research Center,
Sirindhorn International Institute of Technology, Thammasat University, Thailand
pakawat@siit.tu.ac.th2
Graduate Student, School of Civil Engineering and Technology,
Sirindhorn International Institute of Technology, Thammasat University,
Thailand3
Professor, School of Civil Engineering and Technology,
Sirindhorn International Institute of Technology, Thammasat University, Thailand

ABSTRACT
Sacrificial anode cathodic protection is one of prevention and repairing methodsof corrosion of reinforcing steel in RC structure. Its performance mainly depends
on anode material and electrical resistivity of concrete. This study determined
performance of different sacrificial anode materials which are aluminum alloy,
zinc alloy and alkaline activated zinc alloy to protect corrosion if reinforcing steel
in different concrete mix proportion. Half-cell potential and corrosion current
density of reinforcing steel at different distance from sacrificial anode were
measure weekly. The results showed that aluminum alloy has the highest
performance of corrosion protection because of its lowest natural potential.
Higher chloride content in concrete and lower water to binder ratio caused
higher electrical resistivity of concrete reducing the performance of corrosion
protection of sacrificial anode. The results can be used for designing sacrificial
anode to protect corrosion of reinforcing steel in RC structure.
Keywords: corrosion, cathodic protection, sacrificial anode, maintenance

1. INTRODUCTION
Corrosion of reinforcing steel in reinforced concrete structure is one of the mostimportant problems around the world. Thailand is also now approaching the aging
infrastructure era. The effective maintenance methods are needs to be concernedin order to ensure safety of structures and resources saving. Cathodic protection is
one of promised methods to prevent or delay corrosion deterioration of RC
structures (Sancharoen et al., 2008 and DNV, 2010). Impressed current andsacrificial anode are two major categories of cathodic protection. One needs the
supply of external electricity while another requires 2 metals with different
potential in galvanic series. This study mainly focused on effectiveness of
sacrificial anode system. In case of normal reinforcing steel in RC structure,1159

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Vietnamaluminum alloy and zinc alloy are widely used as sacrificial anode due to theirpotential is more negative than that of steel. Unfortunately, current design
guidelines of cathodic protection systems (DNV, 2010) are generally concerned
about underground or underwater steel structure. In case of RC structure, there islittle information regarding to the design of sacrificial anode for RC structures. So
this study aims to study the effectiveness of different sacrificial anode materials toprotect reinforcing steel in different concrete mix proportions from corrosion due
to chloride attack. The results can be used as the guideline for material selections,system designing and installation and service life evaluation of repairing structureby sacrificial anode.

2. EXPERIMENTAL PROGRAM
2.1 Materials
2.1.1 Concrete
As electrical resistivity of concrete affects the effectiveness of sacrificial anode,various concrete mix proportions were prepared. Cement is ordinary Portland
cement type 1 accordingly to ASTM C150. Sand and gravel are natural river sandand crushed limestone aggregate according to ASTM C33. Water to cement ratio
were varied as 0.4, 0.5 and 0.6 as shown in Table 1. Chloride was initially mixed
in mixing water in form of sodium chloride (NaCl) in order to obtain chloride
concentration as 1%, 2% and 4% of chloride by weight of cement.
2.1.2 Reinforcing steel
Reinforcing steel used in this study was DB12 grade SD40 according to TIS 202543. It was cut to the length of 140 mm. Then, reinforcing steel was polished its
surface by wire brush to remove rust and oxide films. Electrical wire wasconnected to one end. Exposed surface area of steel for testing was controlled bycoating both ends of steel by epoxy coating. The exposed steel length was 80 mm
in the center. Before casting, steel surface was degreased by acetone and clean by
distilled water. Prepared reinforcing steel was shown in Figure 1.
Table 1: Concrete Mix Proportions

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W/C

0.4OPC-4%CL
0.5OPC-1%CL
0.5OPC-2%CL
0.5OPC-4%CL
0.6OPC-4%CL

0.4
0.5
0.5
0.5
0.6

Cement
454
399
399
399
355

Unit content (kg/m3)
Water
Sand
Gravel
182
720
1032
199
720
1032
199
720
1032
199
720
1032
213
720
1032

NaCl
18.16
4.02
8.01
15.96
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Figure 1: Prepared reinforcing steel
2.1.3 Sacrificial anodeAl anode and Zn anode were used as sacrificial anode. They were prepared andsupported by Thai Naval Dockyard, Royal Thai Navy. Their chemicalcompositions and electrochemical properties were shown in Table 2 and Table 3.
However, some literatures showed that Zn anode has problem about formed zincoxide film that reduced current discharge. Therefore, this study also prepared zincsacrificial anode coated by high alkalinity mortar backfill. Lithium hydroxide(LiOH) were mixed in the mortar to increase pH around zinc sacrificial anode anddissolve the zinc oxide film and maintain current flow of zinc alloy. Preparedsacrificial anodes were shown in Figure 2.
Table 2: Chemical Compositions of Sacrificial Anode
Anode
Al
Zn

Chemical Composition (% by weight)
Fe
Pb
Cd
Sn
Al
Cu
In
Zn
Si
Remain0.0140.080.090
0.001
0.004
4.0-6.5
der
0.020
0.20
0.025Remain0.005 0.006
0.1-0.5 0.005
0.07
derTable 3: Electrochemical Properties of Sacrificial Anode

Anode
Al
Zn

Density
Potential
Current capacity(g/cm3) (mV vs. Ag/AgCl)(Ah/kg)2.699
1050.67
2566.06
7.133
1006.33
783.41

Consumption rate
(g/Ah)
0.390
1.276

2.2 Specimen preparation
RC specimen designed specially to study effectiveness of sacrificial anodecathodic protection as shown in Figure 3. Specimen size was 100 cm in length and
10 cm × 10 cm in cross section. Reinforcing steel were installed at varying
distance from anode as the 1st to the 5th positions of steel was 5 cm interval, the
5th to the 7th was 10 cm interval and the 7th to the 9th was 20 cm interval.
Performance of different sacrificial anode materials on corrosion protection of
Performancereinforcingof differentsteel
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October
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Vietnam

(a)
(b)
(c)
Figure 2: Prepared sacrificial anode (a) Aluminum alloy anode (b) Zinc alloy
anode (c) Coated zinc alloy anode

Figure 3: Specimen Preparation
Sacrificial anode was installed far from the 1st steel position for 8 cm. Concrete
was casted and let harden in the mold for 1 day. Then, specimens were cured bybeing covered with wet cloth for another 7 days.

2.3 Measurements
2.3.1 Half-cell potential measurement
Half-cell potential measurement (HCP) at concrete surface was conducted for all
reinforcing steel positions and anode in each concrete specimen as shown in
Figure 3. Copper/copper sulfate electrode (Cu2+/CuSO4) was used. HCP testing
was conducted at three conditions; on potential, instant-off potential and off
potential, according to NACE standard. On potential condition was tested whenanode and steel were always connected by electrical wire. Instant-off condition
was tested when anode was disconnected from steel within 15 minutes. Off

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potential condition was tested when anode disconnected from steel more than 4hours. The external switching box was used to disconnect electrical connection
between anode and steel.
2.3.2 Current flow measurement
Sacrificial anode current density flow is very important to effectively design
sacrificial anode cathodic protection in concrete. So, current density requirements
to protect reinforcing steel were shown in Table 4.
Current flow between sacrificial anode and steel was conducted by measuring
electrical voltage dropped across the external resistor as shown in Figure 4. By
Ohm’s law, current flow can be calculated as shown in Equation (1)V = IR(1)

Where V = Electrical voltage dropped across external resistor (Volt), I = Current
Flow (Amp), R = Resistance of external electrical resistor (Ohm)
2.3.3 Concrete resistivity
Resistivity of concrete is very important factor affecting performance of sacrificial
anode system. Resistivity was measured by commercial Wenner’s four probes
according to AASHTO TP 95-11 as shown in Figure 4.
Table 4: Current Density Requirements to Protect Corrosion of Reinforcing Steel
Environment surrounding reinforcing steel
Alkaline, no corrosion, low oxygen
Alkaline, no corrosion, exposed structure
Alkaline, chloride present, dry
Chloride present, wet, poor quality concrete andgeneral corrosion
High chloride level, wet fluctuating
environment, high oxygen level, hot, severe
corrosion on steel

Current density requirement(mA/m2)
0.1
1-3
3-7
8-20
30-50

Figure 4: Concrete Resistivity Measurement

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3. RESULTS AND DISCUSSION
3.1 General
Figure 5 shows general results of half-cell potential measurement at different
conditions as initial, on-potential, instant off-potential and off-potential. The
results showed half-cell potential of steel at distance 5cm, 35cm and 85cm fromanode. As shown, on-potential showed the lowest value meaning steel waspolarized by anode. However, please be noted that polarized potential criteria ofacceptance sacrificial anode system according to DNV and NACE standard at 850mV cannot be used for RC structure because of very high electrical resistivityof concrete compared to soil or water. The 100mV decay shift of potential
between instant off-potential and off-potential criteria was used instead.

Figure 5: General of Half-cell Potential Results

3.2 Effect of different sacrificial anodes
Figure 6 shows the results of half-cell potential of steel polarized by different
sacrificial anode. As shown, none of all sacrificial anodes passed the -850mV
criteria of NACE standard. However, aluminum alloy anode can polarize steel tobe the lowest potential due to its more negative potential than zinc alloy anode.
Comparison between result of zinc alloy and coated zinc alloy anodes shows
clearly the benefit of high alkalinity around zinc alloy. As pH more than 13.2,
calcium hydroxyzincate film was destroyed. Therefore, potential and current flowfrom coated zinc anode to steel was improved.
Similarly, due to higher current capacity of aluminum alloy anode, discharged
current density of aluminum anode was higher than that of zinc as shown in
Figure 7. Also the improvement of current discharge due to high alkalinity mortar
coated zinc anode can be observed in Figure 7.

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3.3 Effect of different concrete mix proportions on half-cell potential
Figure 8 shows effects of different water to cement ratio on half-cell potential ofsteel. As shown, there is no significantly different on polarized potential of steel at
different concrete mix proportion. This may due to thee testing condition is wet
condition. So concrete is continuously wet causing no significantly different in
concrete resistivity as shown in Figure 9.

Figure 6: Effect of Different Sacrificial Anodes on Half-cell Potential

Performance of different sacrificial anode materials on corrosion protection of
Performancereinforcingof differentsteel
sacrificial anode materials on corrosion protection of reinforcing steel1165

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 7: Effect of Different Sacrificial Anodes on Current Density (a) Aluminum
anode (b) Zinc anode (c) Coated zinc anode

Figure 8: Effect of Water to Cement Ratio on Half-cell Potential (a) w/c = 0.4 (b)w/c = 0.5 (c) w/c = 0.6

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Figure 9: Results of Concrete Resistivity
Figure 10 shows effects of different chloride content on half-cell potential of steel.
As shown, steel was polarized to be more negative potential when chloride
content was increased. This is due to the significantly change, almost 50%
reduction, of concrete resistivity as shown in Figure 9. Similarly, current densityof higher chloride content specimen was higher than that of lower chloride content
as shown in Figure 11. This was due to lower concrete resistivity and severe
corrosion of reinforcing steel in higher chloride content.

Figure 10: Effect of Chloride Content on Half-cell Potential (a) 0.5OPC-1%CL(b) 0.5OPC-4%CL

Figure 11: Effect of Chloride Content on Current Density (a) 0.5OPC-1%CL (b)0.5OPC-4%CL
Performance of different sacrificial anode materials on corrosion protection of
Performancereinforcingof differentsteel
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Vietnam

4. CONCLUSIONS
Based on 100mV decay shift criteria, all of anodes can protect reinforcing steel inwet concrete from corrosion even at the distance of 85 cm from anode. Polarized
potential and current density of steel connected to zinc anode was the worst due toformed passive film which can be solved by coating zinc by high alkalinity mortar.
Water to cement ratio did not significantly affect effectiveness of sacrificial anodebecause testing was conducted in wet condition. More severe conditions as wetdry and dry condition are conducting. Higher chloride content in concrete reduced
concrete resistivity significantly and caused more severe corrosion. Therefore,
potential and current density were affected. The results can be used as a guideline
to design sacrificial anode system to protect corrosion of reinforcing steel more
effectively.

ACKNOWLEDGEMENTS
Sacrificial anodes were supported by Thai Naval dockyard, Royal Thai Navy.

REFERENCES
DNV-RP-B401, 2010. Cathodic protection design. Recommended practice of
DET NORSKE VERITAS.
Sancharoen, P., Kato, Y., and Uomoto, T., 2008, Probability-based maintenanceplanning for RC structures attacked by chloride, Journal of Advanced Concrete
Technology, Vol.6, No.3, pp.481-495.
Yeomans, S. R., 2004, Galvanized Steel Reinforcement in Concrete, Elsevier
Science, United Kingdom

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Investigation on performance of concreteand mortar using active compound powder
Parnthep JULNIPITAWONG1, Chalermchai WANICHLAMLERT2
1,2
Researcher, Construction and Maintenance Technology Research Center,
Sirindhorn International Institute of Technology, Thammasat University, Thailand
parnthep@siit.tu.ac.th
ABSTRACTThe early-age properties of low slump concrete and mortar with the active
compound were investigated. The active compound was used as an additive andreplacement material with varied content. The expansion of mortar samples
containing the active compound stored in water and the autoclave expansion of
paste bar samples containing the active compound were used to determine
durability properties. The long term durability property such as carbonation
resistance was also investigated. It was found that as consequence of using theactive compound as an additive material the early-age compressive strength andslump of concrete were improved. The expansion of mortar due to storage inwater was in the limit of the standard when incorporated with limestone powder.
The autoclave expansion of paste bar sample containing the active compound wasless than that of the control sample. The carbonation resistance of concrete wasmuch obviously improved
Keywords: active compound, early-age, additive material
1. INTRODUCTION
In concrete industry nowadays, the demand for high early strength concrete isapparently increasing for reasons of high business competition. The application ofhigh early strength concrete includes old as well as new structures. According to
its fast strength development, it is excellent for concrete repair work, especiallywhere the concrete structures cannot be closed for a long period. High earlystrength concrete is very useful for opening up concrete pavements to traffic
earlier than conventional concrete mixtures. Moreover, high early strength
concrete is also excellent for the precast concrete industry as the faster thestrength gain is, the faster the production process will be. There are several ways
to achieve high early strength of concrete. The most common way is to use highearly strength cement (Portland cement type 3). In Thailand, even though thePortland cement type 3 is available in the construction market, but it costs about
10% more than ordinary Portland cement type 1. Furthermore, the cost of concreteis the main criterion for user to decide whether that type of concrete shall beselected or not. Another alternative to make concrete achieve high early strength
is to use mineral admixtures such as pozzolanic materials, fillers etc. to partiallyreplace some amounts of the cement. In previous days, most of the mineral1169

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamadmixtures were reactive powder materials which obtained from other industries
as by-products. At present, scientists can synthesize and create special selective
mineral admixtures to improve the reaction under certain circumstance as needed.
This synthesis admixture is able to be directly involved in the hydration reactionof cement. This type of admixture usually has a chemical composition similar to
those of cement compositions that provide the reaction at early-age stage.
However, overdosing of this kind of admixture could lead to the problem ofexcessive expansion. The existence of any mineral admixtures in concrete can beconsidered as the modification of cement in both terms of physical properties andchemical composition, which affects concrete properties. The concrete properties
can be separated according to the age of concrete as early-age properties, and longterm properties. The early-age properties are investigated in a preliminary study todetermine whether a certain admixture could be used in concrete without adverse
effects. These concrete properties include workability, setting time, compressive
strength development. The long term properties which mostly are related to
durability properties have to be determined to ensure that the desired engineering
properties are maintained.
2. OBJECTIVES AND SCOPES OF THE STUDYThis research is aimed to investigate performance of concrete and mortar using anactive compound by comparing the workability, mechanical and durability
properties with those of the control concrete and mortar without an active
compound.
3. MATERIALS AND MIX PROPORTIONS
Ordinary Portland cement type 1, fly ash, limestone powder with mean particle
size of 3 micron and the active compound were used in this study. The active
compound was used as a mineral admixture. For simplification, the following
notations are used to specify each type of materials; OPC1 is Ordinary Portland
cement type 1. FA is fly ash. LP is limestone powder and AC is the active
compound.
Chemical compositions and physical properties of the OPC1, fly ash and active
compound are tabulated in Table 1.
2.2 Mix proportions
To study the influence of active compound powder on performance of concreteand mortar, OPC1 and OPC1 with LP were blended with the active compound
powder using different addition and replacement percentages. The addition andreplacement percentages of active compound powder were calculated by weightof cement in case of OPC1 mixture whereas calculated by weight of OPC1 and LP
in case of OPC1 - LP mixture. The selected addition and replacement percentagesof active powder were 5.5%, 6.5% and 7.5%. Mix proportions for investigating
workability, compressive strength and carbonation resistance are shown in Table

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2. For the early durability properties investigation, the mix proportions shown in
Table 3 were used. Note that admixture was used in order to achieve the designed
slump criteria.
Table 1 Chemical and physical properties of OPC, fly ash and active compound
Chemical and Physical
Properties
Chemical
SiO2
Compositions* Al2O3
Fe2O3
CaO
MgO
SO3
Na2O
K2O
TiO2
P2O5
PhysicalDensityproperties
Blaine surface
area (cm2/g)
Loss onignition(*) by XRF analysis

OPC1

Fly ashActive compound

17.72
3.78
3.64
66.76
1.42
4.32
0.24
0.60
0.25
0.07
3.15
3300

33.41
18.74
15.03
20.01
2.02
5.19
1.27
2.92
0.49
0.22
2.24
2578

1.76
0.36
0.31
43.96
0.24
48.79
0.60
0.08
0.02
0.01
2.95
2984

1.06

0.23

3.78

4. METHODOLOGY
4.1 Workability and compressive strength measurements
The initial slump of all concrete was controlled at 50±20 mm. The slump loss wasmeasured every 15 minutes.
The compressive strength of concrete was measured on seal-cured cube samples
with dimension of 100x100x100 mm. The testing ages were 18 hrs, 1 day and 3days.
4.2 Durability properties measurements
Regarding the high content of SO3 in the active compound the measurement ofvolume stability of the sample is significant. The selected measurements wereautoclave expansion (ASTM C151) and expansion of mortar bars stored in water(ASTM 1038). The paste bars and mortar bars with dimension of 25x25x285 mm
were cast for autoclave test and the expansion of mortar bars stored in water test,
respectively. The carbonation depth of 100x100x100 mm concrete samples
containing the active compound was investigated and compared to those of thecontrol samples. The concrete samples were seal-cured until 7 days before storingin the carbonation chamber. The concrete samples were carbonated under acarbon dioxide concentration of 4% (40,000 ppm) in the accelerated carbonation
InvestigationInvestigationon performanceof concrete andmortar using
active using
compoundon performanceof concreteand mortar
activepowder
compound powder1171

October
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Hanoi,
Vietnam0ctober
0ctober
2013,
2013,
Hanoi,
Hanoi,
VietnamVietnamchamberchamber
forforperiods
periodsof of
4 weeks.
4 weeks.
TheThetemperaturetemperature
andandrelative
relative
humidity
humidity
in inthethecarbonation
carbonationchamberchamberwere
werecontrolledcontrolled
at 40°Cat 40°C
andand55±5%55±5%relative
relative
humidity.
humidity.
Table
Table
2 Mix
2 Mix
proportions
proportions
forforinvestigating
investigating
workability
workability
compressive
compressive
strength
strengthandandcarbonation
carbonation
resistanceresistanceof concreteof concreteMixMix� � w/bw/b C C
LPLP
ACAC
WW
S S
G G
AdmixAdmix3 3
3 3
3 3
3 3
3 3
3 3
(kg/m
(kg/m
) ) (kg/m(kg/m) )(kg/m(kg/m) )(kg/m(kg/m) )(kg/m(kg/m) )(kg/m(kg/m) )ture
ture
3 3
(cc/m
(cc/m
) )
OPC1
OPC1
g1.38
g1.38 1.38
1.380.30
0.30554554- - 159159 742742 980980 7473
7473
OPC1+AC5.5
OPC1+AC5.5 1.38
1.380.30
0.30554554- 30 30
161161 742742 980980 5536
5536
(add)
(add)
OPC1+AC6.5
OPC1+AC6.5 1.38
1.380.30
0.30554554- 36 36161161 742742 980980 5536
5536
(add)
(add)
OPC1+AC7.5 1.38
1.380.30
0.30554554
5536
OPC1+AC7.5- 42 42161161 742742 980980 5536
(add)
(add)
OPC1
OPC1
g1.4
g1.4 1.40
1.400.30
0.30562562- - 163163 736736 972972 5618
5618
OPC1+AC5.5- 30 30
164164 736736 972972 4239
OPC1+AC5.5 1.40
1.400.30
0.30530530
4239(replace)(replace)
OPC1+AC6.5
OPC1+AC6.5 1.40
1.400.30
0.30524524- 36 36164164 736736 972972 4193
4193
(replace)(replace)- 42 42164164 736736 972972 4147
OPC1+AC7.5
OPC1+AC7.5 1.40
1.400.30
0.30518518
4147(replace)(replace)
OPC+LP1052 52
0 0149149 765765 1011
OPC+LP10 1.30
1.300.30
0.30465465
1011 6193
6193
OPC1+LP10+
52 52
28 28
150150 765765 1011
OPC1+LP10+ 1.30
1.300.30
0.30465465
1011 4645
4645
AC5.5
(add)
AC5.5
(add)
OPC1+LP10+
52 52
34 34
150150 765765 1011
OPC1+LP10+ 1.30
1.300.30
0.30465465
1011 4645
4645
AC6.5
(add)
AC6.5
(add)
OPC1+LP10+
52 52
39 39
150150 765765 1011
OPC1+LP10+ 1.30
1.300.30
0.30465465
1011 4645
4645
AC7.5
(add)
AC7.5
(add)
OPC+LP10
OPC+LP10 1.40
1.400.30
0.30501501
56 56
0 0
162162 736736 972972 5013
5013
g1.4
g1.4
56 56
31 31
164164 736736 972972 3152
OPC1+LP10+
OPC1+LP10+ 1.40
1.400.30
0.30470470
3152
AC5.5
AC5.5
(replace)(replace)
OPC1+LP10+
OPC1+LP10+ 1.40
1.400.30
0.30464464
56 56
36 36
164164 736736 972972 3118
3118
AC6.5
AC6.5
(replace)(replace)
OPC1+LP10+
OPC1+LP10+ 1.40
1.400.30
0.30458458
56 56
42 42
164164 736736 972972 3084
3084
AC7.5
AC7.5
(replace)(replace)
OPC1**
OPC1**
1.20
1.200.50
0.50362362- - 181181 1050
1050 795795 - OPC1+FA20*
OPC1+FA20* 1.20
1.200.50
0.50281281- FA*=7
FA*=7 175175 1050
1050 795795 - * *0 0
OPC1+RK5.5- 20 20181181 1050
OPC1+RK5.5 1.20
1.200.50
0.50362362
1050 795795 - add**
add**
OPC1+RK6.5
OPC1+RK6.5 1.20
1.200.50
0.50362362- 24 24
181181 1050
1050 795795 - add**
add**

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OPC1+RK7.5
OPC1+RK7.5 1.20
1.200.50
0.50362362- 27 27
181181add**
add**
OPC1+RK5.5
OPC1+RK5.5 1.20
1.200.50
0.50341341- 20 20181181
replace**replace**
OPC1+RK6.5
OPC1+RK6.5 1.20
1.200.50
0.50338338- 24 24
181181
replace**replace**
OPC1+RK7.5
OPC1+RK7.5 1.20
1.200.50
0.50334334- 27 27
181181
replace**replace**(*)(*)
FAFA
is flyis flyash,ash,(**)(**)
mixmixproportions
proportionsof carbonationof carbonation
testtest

1050
1050 795795

- -

1050
1050 795795

- -

1050
1050 795795

- -

1050
1050 795795

- -

Table
Table
3 Mix
3 Mix
proportions
proportions
forforinvestigating
investigating
durability
durability
properties
propertiesof mortarsof mortars
Mix
Mix
OPC1
OPC1
OPC1+AC5.5
OPC1+AC5.5
(add)
(add)
OPC1+AC6.5(add)
OPC1+AC6.5(add)
OPC1+AC7.5
OPC1+AC7.5
(add)
(add)
OPC1+AC5.5
OPC1+AC5.5(replace)(replace)
OPC1+AC6.5
OPC1+AC6.5(replace)(replace)
OPC1+AC7.5(replace)
OPC1+AC7.5(replace)
OPC+LP10
OPC+LP10
OPC1+LP10+
OPC1+LP10+
AC5.5
AC5.5
(add)
(add)
OPC1+LP10+
OPC1+LP10+
AC6.5
(add)
AC6.5
(add)
OPC1+LP10+
OPC1+LP10+
AC7.5
(add)
AC7.5
(add)
OPC1+LP10+
OPC1+LP10+
AC5.5(replace)AC5.5(replace)
OPC1+LP10+
OPC1+LP10+
AC6.5(replace)
AC6.5(replace)
OPC1+LP10+
OPC1+LP10+
AC7.5
AC7.5
(replace)(replace)

OPC
OPC(%)(%)
100100100100100100100100
94.5
94.5
93.5
93.5
92.5
92.5
90 90
90 90

LPLP
(%)(%)- - - - - - - 10 10
10 10

ACAC
(%)(%)- 5.55.5
6.56.5
7.57.55.55.5
6.56.5
7.57.5- 5.55.5

90 90

10 10

6.56.5

90 90

10 10

7.57.5

84.5
84.5

10 10

5.55.5

83.5
83.5

10 10

6.56.5

82.5
82.5

10 10

7.57.5

5. RESULTS
5. RESULTS
AND
AND
DISCUSSIONSDISCUSSIONS
5.15.1
Slump
Loss
Slump
Loss
TheTheslump
slump
losslossresults
results
of of
OPC1
OPC1
containing
containing
different
different
percentages
percentages
of ofactiveactivecompound(AC)
areareshown
in in
Fig.Fig.
5.15.1(a) (a)andand(b)(b)
forforboth
addition
andandcompound
(AC)
shown
both
addition
replacementcases.
From
thetheFig.Fig.
5.15.1(a) (a)additioncase,
it wasfound
thatthatslump
replacementcases.
From
additioncase,
it wasfound
slump
retentionof ofconcretecontaining
activecompoundwaswasbetterthanthatthatof ofthetheretention
concretecontaining
activecompoundbetterthan
OPC1
concrete.
Fig.Fig.
5.15.1(b)(b)
shows
thatthat
using
thetheactivecompoundas replacement
OPC1
concrete.
shows
using
activecompoundas replacement
material
causedlongerslump
retention.
material
causedlongerslump
retention.

Investigationon performanceof concreteandmortaractivecompoundpowderInvestigationon performanceof concreteandmortarusing
activecompoundpowderInvestigationon performanceof concrete
andusing
mortarusing
activecompoundpowder1173

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In the case of concrete containing limestone powder, using the active compound
as additive material (% by weight of binder) increased slump retention and slump
retention was longer than that of the OPC1 concrete (Fig. 5.2 (a)).
Using the active compound as replacement material, the concrete mixture with
7.5% of active compound (% by weight of binder) increased slump retention
while the other replacement percentages did not show different slump retention
from the control mix as shown in Fig. 5.2 (b).
100

OPC1+AC5.5(add) g1.38

80

OPC1+AC7.5(add) g1.38
60

40

OPC1+AC5.5(re) g1.40
OPC1+AC6.5(re) g1.40
OPC1+RK7.5(re) g1.40

60

40

20

20

0

OPC1 g1.4

80

OPC1+AC6.5(add) g1.38

Slump retention (%)

Slump retention (%)

100

OPC1 g1.38

0
0

15

30
Elapsed time (min)

45

60

0

15

30
Elapsed time (min)4560(a) addition case(b) replacement caseFig. 5.1 Slump loss of OPC1 concrete with and without active compound
100

100

OPC1+LP10 g1.4

OPC1+LP10 g1.3
OPC1+LP10+AC5.5(add) g1.3
OPC1+LP10+AC7.5(add) g1.3
60

40

20

0

OPC1+LP10+AC5.5(re) g1.4

80

OPC1+LP10+AC6.5(add) g1.3

Slump retention (%)

Slump retention (%)

80

OPC1+LP10+AC6.5(re) g1.4
OPC1+LP10+AC7.5(re) g1.4

60

40

20

0

15

30
Elapsed time (min)

45

60

0

0

15

30
Elapsed time (min)

45

60

(a)
(b)
Fig. 5.2 Slump loss of OPC1-LP concrete with and without active compound
5.2 Compressive strength
From Fig. 5.3, using active compound as additive material was effective inincreasing early-age compressive strength of OPC1 concrete at the ages of 18 hrs,
1 day, 3 days. Especially at the age of 18 hrs the compressive strength of OPC1
was increased to 16% when using 6.5% of the active compound.

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However, by using the active compound as replacement material, the compressive
strength of OPC1 concrete containing the active compound were lower than thatof OPC1 concrete at early-ages (Fig.5.4) when using 5.5% and 7.5% of the active
compound.
700

OPC1 g1.38

OPC1+AC5.5(add)

OPC1+AC6.5(add)655Compressive Strength (Ksc)

600

536

500
400

OPC1+AC7.5(add)

396

434

487

460

531

536

629

579

624

405

300
200
100
0

18hr

1 day
Age

3 daysFig. 5.3 - Compressive strength of OPC1 concrete with and without
active compound (addition case)

700

OPC1 g1.4

OPC1+AC5.5(RE)OPC1+AC6.5(RE)Compressive Strength (Ksc)

600
500

423

416

428

400

470

464

488

OPC1+AC7.5(RE)

632

607

620

600

467

393

300
200
100
0

18hr

1 day
Age

3 daysFig. 5.4 Compressive strength of OPC1 concrete with and without
active compound (replacement case)Fig. 5.5 and Fig. 5.6 show the compressive strength results of limestone powder
concrete containing the active compound as an additive and replacement material(% by weight of binder). It can be seen from Fig. 5.5 that using the active
compound as aan dditive material resulted in increase in compressive strength oflimestone powder concrete at the ages of 18hrs, 1 day and 3 days. At the age of
18hrs the compressive strength of concrete containing 6.5% of active compound
obviously increased up to 20% of that of the control concrete sample.

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compoundon performanceof concreteand mortar
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compound powder1175

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OPC1 +LP10 g1.3

OPC1+LP10+AC5.5(add)

OPC1+LP10+AC6.5(add)

OPC1+LP10+AC7.5(add)Compressive Strength (Ksc)

700
579

600
500
400

362

404

435

410

440

479

498

612

627

619

508

300
200
100
0

18hr

1 day
Age

3 daysFig. 5.5 Compressive strength of OPC1-LP concrete with and without
active compound (addition case)On the contrary, using more the active compound as replacement material caused
reduction in compressive strength at the ages of 18hrs and 1 day (Fig. 5.6).
700

OPC1+LP10 g1.4

OPC1+LP10+AC5.5(re)OPC1+LP10+AC6.5(re)584Compressive Strength (Ksc)

600

532

500
400

OPC1+LP10+AC7.5(re)

456
398

396

363

535

542

462
399

406

345

300
200
100
0

18hr

1 day
Age

3 daysFig. 5.6 Compressive strength of OPC1-LP concrete with and without
active compound (replacement case)
5.3 Volume stability
Fig. 5.7 (a) shows the length change in microns where (+) sign means expansionand (-) means shrinkage of mortar bar samples containing OPC1 with and without
the active compound as an additive and replacement material. The figure showedthat using higher percentages of addition or replacement of active compoundincreased the expansion of the samples when stored in water. Moreover, theexpansion of the mortar samples exceeded 200 microns as specified by ASTM
C150 in some mixtures. The expansions of limestone powder mortar samples withthe active compound are shown in Fig. 5.7 (b). It is also obviously seen that thehigher the content of active compound used, the more expansion of mortar sample
was obtained. In specific case the expansion of samples exceeded 200 microns as
specified by ASTM C150.

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ICUS Report 73(a) OPC1 mortar samples(b) OPC1-LP mortar samples
Fig. 5.7 Expansion of mortar samples after 14 days stored in water
From Fig. 5.8 (a), it can be seen that all cement paste bars with the active
compound as an additive and replacement material showed less expansion (+means shrinkage) than that of the OPC1 paste sample. The test results passed the
ASTM C151 standard which allows 0.8% maximum autoclave expansion. The
OPC1-LP paste samples containing active compound showed shrinkage results
and were below 0.8% as shown in the Fig 5.8 (b).

(a) OPC1 paste samples(b) OPC1-LP paste samples
Fig. 5.8 Expansion of mortar samples after autoclave test
5.4 Carbonation
From Fig. 5.9 (a) and (b) considering the 7-day seal-cured samples, allcarbonation depths of concrete samples containing the active compound werelower than those of the control samples. Concrete samples containing the active
compound as additive material showed increase in carbonation depth when theactive compound content was increased. On the contrary, the carbonation depths
of concrete samples decreased when increasing the active compound content incase of using the active compound as replacement material.

InvestigationInvestigationon performanceof concrete andmortar using
active using
compoundon performanceof concreteand mortar
activepowder
compound powder1177

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnam(a) addition case(b) replacement caseFig. 5.9 Carbonation depth of 7-day seal-cured concrete samples containing
active compound compared with those of the control samples at 28 days
6. CONCLUSIONS
In general the application of active compound powder as an additive material inconcrete mixture improves fresh and hardened concrete properties, i.e., increasing
slump retention, increasing early compressive strength especially in case of using
the active compound as an additive material in the OPC1-LP mixture. The
increase in compressive strength can be attributed to decrease in porosity (Chan etal., 2000). Regarding durability of concrete containing the active compound it isfound that the autoclave expansion of mixtures containing the active compoundare under 0.8% as specified by ASTM 151 standard. Higher addition content of
the active compound causes an increase in expansion in water but less than 200
microns as prescribed by ASTM 150, when incorporated with limestone powder.
However, this standard test has shortcomings for the evaluation of internal sulfate
attack. Yan et al. (1997) reported that in some cases samples showing an
expansion less than 0.02% at 14 days had much higher expansion five years later.
In case of carbonation resistance using the active compound as additive material,
between 5.5% and 6.5% and seal curing generally provide better carbonation
resistance of concrete than those of the control samples.
7. REFERENCES
ASTM 150-00, Standard specification for Portland cement, Annual Book of ASTM
Standards, Vol. 4.01, 2000.
ASTM C151-00, Standard test method for autoclave expansion of Portland
cement, Annual Book of ASTM Standards, Vol. 4.01, 2000
ASTM C1038-00, Standard test method for expansion of Portland cement mortar
bars stored in water, Annual Book of ASTM Standards, Vol. 4.02, 2000.
Chan, Y.N., Luo, X., Sun, W, 2000. Compressive strength and pore structure ofhigh-performance concrete after exposure to high temperature up to 800°C.
Cement and Concrete Reasearch 30, 247-251.
Yan, F., Jian, D., J.J., Beaudoin., 1997. Expansion of Portland cement mortar due
to internal sulphate attack. Cement and Concrete Research 27, 1299-1306.

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A simple method to determine
the unsaturated soil shear strengthwith respect to a wide range of matric suction
Hoang Viet NGUYEN1 and Thi Dieu Chinh LUU2
1
Lecturer, Soil Mechanics and Foundation Department,
National University of Civil Engineering, Vietnam
nhvdhxd@gmail.com
2
Lecturer, Water Resources and Hydropower Department,
National University of Civil Engineering, Vietnam
ABSTRACTTo determine the shear strength parameters of unsaturated soils, normally asophisticated and time consuming testing programme needs to be carried out.
This paper proposes a simple method, which based on two types of test series: thefirst series is used to determine the soil water characteristics curve by filter paper
method; and the second series is the direct shear tests carried out on the soil at
unsaturated state with different water contents. Finally, the nonlinear
characteristic of shear strength envelope of unsaturated soils with respect to alarge range of matric suction (up to 15600 kPa) is introduced.
Keywords: unsaturated soil, shear strength, filter paper, direct shear test, matricsuction
1. INTRODUCTION
There is no doubt that unsaturated soil mechanics has already played an importantrole in geotechnical engineering practice. However, there are some challenges,
which have been contributing to the complex, time consuming attributes of
unsaturated soil mechanics. The shear strength properties of unsaturated soil are
far more complicated than those of saturated soils. It is not only because oflaboratory apparatuses used to measure unsaturated soils properties are thetechnically demanding and quite complex to operate, but also highly negative
pore-water pressure is difficult to measure, particularly, in the field (i.e., matricsuctions greater than 100 kPa) (Fredlund 2006). In addition, the surface tension of
the water-air interface in unsaturated soil also causes more difficulty to extend theformulas for describing the behavior of saturated soils to unsaturated soils (Ye et
al. 2010).
The triaxial or direct shear apparatus, that modified to allow for the control andmeasurement of pore-air and pore-water pressures, are often used (Bishop et al.
1960; Escario & Saez 1986; Gan, Fredlund & Rahardjo 1988; Ho & Fredlund
1982; De Campos & Carrillo 1995; Oloo & Fredlund 1996). However, theequipment and level of expertise required for the characterization of using these1179

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Vietnam0ctober
Vietnamtests are beyond the capabilities of most geotechnical laboratories. Furthermore,
the time required to perform the tests runs into weeks or even months dependingon the coefficient of permeability of the soil being tested (Oloo & Fredlund 1996).
Although, the unsaturated shear strength can also be predicted by combining theshear strength parameters determined at saturated state with the Soil – Water
Characteristic Curve (SWCC) property. Several procedures have been proposed in
the literature to predict the shear strength of an unsaturated soil (Fredlund et al.
1996; Vanapalli et al. 1996; Öberg & Sällfors 1997; Khalili & Khabbaz 1998).
However, these models are still shows remarkable divergence on a wide range ofsuction when the predicted values are compared with the measured values(Vanapalli & Fredlund 2000).
Several test methods have been developed to establish the SWCC. They can bedivided into direct or indirect methods. The direct method measures the negative
pore water pressure due to suction directly, whereas the indirect method requires
the measurement of other parameters such as relative humidity, resistivity,
conductivity or water content and then relates the results to the suction throughcalibration (Nam et al. 2010). The filter paper method is identified as one of two
methods which are having widespread appeal for the measurement of suctions(Ridley et al. 2003).
Since early, Donald (1956) conducted a series of direct shear tests on fine sandsand coarse silts subjected to a negative pore-water pressure. The direct shear
apparatus modified to apply a negative pore water pressure by applying a constantnegative head to the water phase through a membrane at the base of the specimen,
while the soil specimens were exposed to the atmosphere to maintain a pore airpressure, of zero gauge pressure. However, this apparatus limited the appliedmatric suction, to 101 (kPa) due to water cavities in the measuring system at anegative gauge pressure approaching 101 kPa. To solve that problem, Hilf (1956)
suggested that pore-air and pore-water pressures could both be raised to positive
pressure in order to apply matric suctions higher than 101 kPa without cavitation
in measuring system. The proposed procedure is referred to as the axis-translation
technique. This technique is performed with the use of a high air entry disc thatallows the passage of water but prevents the passage of air. As a result, the poreair and pore-water pressures can be controlled or measured independently as longas matric suction of the soil does not exceed the air entry value of the ceramic disc(Gan, Fredlund & Rahardjo 1988).
Using the axis-translation technique, Escario (1980) modified the conventional
direct shear test to be capable of controlling suction during test. A direct shear test
box is placed inside a chamber into which nitrogen under pressure may beintroduced to the upper part of the soil sample through a coarse grained porous
stone. The lower face of the sample is in contact with water at atmosphericpressure through a high air entry value porous stone (1500 kPa). Whenequilibrium is reached, the suction in the pore-water is equal to the applied airpressure. The vertical and lateral forces and displacements are monitored withappropriate push rods (Escario and Saez 1986). Later, the conventional direct
shear test apparatus modified has widely used to study the unsaturated soil shear

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strength (Escario & Saez 1986; Gan, Fredlund & Rahardjo 1988; De Campos &Carrillo 1995).
It is obvious that the unsaturated soil shear strength often requires advanced
apparatus and time consuming test. It becomes an obstacle to apply in engineering
practice. Consequently, there have been a number of efforts to simplify the testingprocedure for determining the unsaturated soil shear strength parameters.
However, it is still a big challenge for geotechnical researchers. Oloo et al. (1996)
proposed a quite simple method for determining the unsaturated soil shear
strength parameter  b for statically compacted soils at different water content.
The test can be performed on a conventional direct shear apparatus. The angle
obtained using the proposed procedure was shown to be comparable to thatobtained using the modified direct shear test. Or Vilar (2006) proposed a
simplified procedure to estimate the shear strength envelope of unsaturated soils,
which is based on an empirical hyperbolic function. The function requires two
input values, namely the shear strength of saturated sample and the shear strengthof an air-dried sample tested without the need for suction control. Nevertheless,the range of matric suction investigated in the study of Oloo et al. is limited (lessthan 450 kPa).
In this paper, a more simpler method is proposed to investigate the unsaturated
soil shear strength with respect to a wide range of matric suction. The method
bases on two types of test series: the first series is used to determine the soil water
characteristics curve by filter paper method; and the second series is the direct
shear tests carried out on the soil at unsaturated state with different water contents.
2. SOIL MATERIAL
The soil used in this study is a slightly expansive soil taken from a cut slope
construction of highway project. After obtaining samples from the site, the soil
was exposed in laboratory under non-controlled temperature and humidity
condition. A wooden hammer was used to beat the soil lumps, when its watercontent was dry enough. After the treatment, an amount of soil grains larger than
2 mm in size was discarded by dry sieving. This process was used to obtain soil
specimens with the original soil structure thoroughly destroyed. In addition, thespecific gravity of soil particles, the liquid and plastic limits of the fines were
determined. Their values are shown in Table 1 as below:
Table 1: Physical Soil Properties
Specific Gravity

Liquid Limit

Plastic Limit

Plasticity Index

Gs

WL (%)

WP (%)

IP

2.7

32.39

20.11

12.28

The soil specimens used in the SWCC test series are the same as those used in the
direct shear test series. They are reconstituted by the static compaction method.
A simplemethod tothe unsaturated
soil shear
A simple method
to determine
thedetermine
unsaturated
soil shear strength
withstrength
respectwith respect to a widerange
ofmatricsuctionto a wide range of matric suction1181

October
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Vietnam

The dimension of soil specimen is 61.8 mm in diameter and 20 mm in height. To
prepare the soil for compaction, the dry soil material is first thoroughly mixed
with distilled water to achieve a water content of 14% by weight; after that it issealed in plastic bag about 24 hours in order to ensure the moisture is uniform
over the whole soil bag. After that the soil material is compacted inside a mould torequired dry density of 1.738 g/cm3. Finally, the specimens are saturated bycreating a vacuum pressure about 100 kPa to evacuate air bubbles for at least 45
minutes, and then water is slowly filling into the voids of specimens.
3. TEST PROCEDURE
3.1 Soil Water Characteristic Curve Tests
In order to estimate the SWCC, 30 points covering the SWCC are proposed to be
carried out by the filter paper method. The calibration filter paper used in thisstudy is Whatman No. 42. The calibration for Whatman No. 42 filter paper
reported by a number of authors and summarized by Crilly, M. S. and R. J.
Chandler (1993) suggest that the measurements fall within a range that is typically25% of the mean. However, by adopting good, consistent methods it is thoughthat better accuracy (e.g. 10%) can be achieved.
In order to obtain one value on the SWCC, it is required to prepare two soil
specimens and three filter paper discs. The diameter of three filter paper discs
needs to be a little bit less than the diameter of soil specimens (about 54 to 58mm). The two soil specimens are taken out of their cut rings together. They aredried up by the natural evaporation process simultaneously until the gravity watercontents of two samples approximately reaching the design value. The three filter
papers are placed on the top surface of one soil specimen. For the contact
procedure, the middle filter paper disc is generally used for the suction
measurement, while the upper and lower filter paper discs are primarily used toprotect the middle disc from soil contamination. Another soil specimen is placed
directly on the three filter paper discs. It means that the intimate contact between
the three filter paper discs and two soil specimens needs to be guaranteed during
equalization period of water content.
Due to the time period required for establishing the equilibrium of water content
between two soil specimens and three filter paper discs is at least 07 days.
Consequently, the 02 soil specimens accompanied with the 03 filter paper discs at
the middle are wrapped in layers of cling film to prevent the decrease in watercontent of two soil specimens by evaporation. At the end of the equalization
period, the filter papers are removed by using a pair of tweezers, and the watercontent of the middle filter paper disc is determined. It is used to interpret thematric suction of two soil specimens.
3.2 Direct Shear Tests
After the soil specimens are saturated by vacuum chamber, they are exposed toatmospheric to let the water in the soil specimens evaporate until their gravimetric

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water contents reach the design value. Before the soil specimens are installed on
the standard direct shear apparatus, the specimens are tested to determine both its
mass and volume due to slightly change in volume during evaporation. Then theunconsolidated-quick shear condition is applied to all the five groups. During
shearing process, the displacement rate of 1.2 mm/minute is imposed (Oloo andFredlund (1996) used a fast rate of 1 mm/minute). Failure usually occurs within 6
minutes of shearing, thus the change in matric suction during the shearing process
is minimized.
The first group includes fifteen saturated soil samples, the others four groups were
unsaturated at different gravimetric water content ranges. The gravimetric watercontent of the soil samples before shearing, wBegin and after shearing, wEnd were
measured by weight. The unsaturated soil specimens and its water contents of thefour groups are summarized in Table 2.
Table 2: Summary of Unsaturated Direct Shear Tests
ID
S1
S2
S3
S4
S5
S6
S11
S12
S13
S14
S15
S16
S25
S24
S23
S22
S21
S26
S31
S32
S33
S34
S35
S36

 (kPa) munsat (g) mdry (g) mw (g) wBegin (%)
50
100
150
200
250
300
50
100
150
200
250
300
50
100
150
200
250
300
50
100
150
200
250
300

122.1
122.8
123.3
122.4
123.1
121.5
115.2
115.0
114.5
114.0
112.5
113.6
108.2
108.2
108.1
108.2
108.0
108.0
120.0
119.9
119.3
119.6
118.9
118.5

104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3
104.3

17.8
18.5
19.0
18.1
18.8
17.2
10.9
10.7
10.2
9.7
8.2
9.3
3.9
3.9
3.8
3.9
3.7
3.7
15.7
15.6
15.0
15.3
14.6
14.2

17.10
17.77
18.25
17.39
18.06
16.53
10.49
10.29
9.81
9.33
7.90
8.95
3.77
3.77
3.68
3.77
3.58
3.58
15.09
14.99
14.42
14.71
14.03
13.65

wEnd (%) Range

wBegin (%)

Range
wEnd (%)

18.18
18.57
16.7118.12 16.5318.57
17.09 18.35
17.28
16.71
10.89
10.79
7.4810.94
7.90-10.87
11.26
10.66
7.48
9.35
3.31
3.51
4.23
3.58-4.44 2.86-4.23
3.61
3.75
3.51
14.89
15.00
13.6414.81 13.6515.09
15.19
15.00
13.76
14.67

A simplemethod tothe unsaturated
soil shear
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to determine
thedetermine
unsaturated
soil shear strength
withstrength
respectwith respect to a widerange
ofmatricsuctionto a wide range of matric suction1183

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4. TEST RESULT AND DISCUSSION
The extended Mohr-Coulomb failure criterion proposed by Fredlund et al. (1978)
is widely accepted for analyzing unsaturated soil shear strength, and it also
applied to analyze the test result from direct shear tests. Nevertheless, the direct
shear test series was carried out on the standard direct shear apparatus atatmospheric condition. Hence, the pore-air pressure gauge is equal to zero( ua  0 ). In order to simplify the analysis of the test results of the unsaturated
direct shear tests, the extended Mohr-Coulomb equation can be rewritten as
follows:

 f  c V tan  S tanb(1)where  f is the shear strength (i.e. the maximum shear stress);  V is the verticalstress applied on the soil specimen during shear (unchanged during shear); S is
the matric suction at failure condition (the maximum duration of shearing is about
7 minutes, thus the matric suction at failure is assumed to equal the matric suction
at the beginning of shearing); c is the cohesion;  is the internal friction angle;

 b is the angle indicating the rate of increase in shear strength relative to thematric suction.
In the plane    , the extended Mohr-Coulomb failure criterion is expressed by
the linear line; the equation of the failure criterion can be changed to: f  capparent  V tan (2)where capparent is the apparent cohesion parameter, equals c  S tan .
b

At failure, the shear stresses along shear surface  f  were measured, they are
depicted again the corresponding applied vertical stress for each test together inFigure 1. Consequently, the extended Mohr-Coulomb failure envelope of eachgroup are gained by using a linear least square fitting method, and also illustrated
in the figure. Thus, the apparent cohesion and internal friction angle shear strengthparameters are deduced for each group of separated water content, and presented
in Table 3.
Table 3: Shear Strength Parameters for the consistent range of vertical stressGroup
Saturation
Unsaturation

Gravimetric Water
Content - wBegin (%)

20.50%
16.53  18.35%
13.65  15.09%
7.90  10.87%
3.58  4.44%

capparent (kPa)
2.84
14.75
48.45
128.77205.94tan( )

0.54396
0.54396
0.677530.89482
1.17110

(0 )
28.5
28.5
34.1
41.8
49.5

Figure 1 shows that the tendency of the increase in the apparent cohesion andinternal friction angle parameters with the decrease in the gravimetric water

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content is obvious, and it is similar to the conclusion reported by Escario & Saez(1986), and Oloo & Fredlund (1996).
UU w = 20.50%
UNS w = 16.53% - 18.35%
UNS w = 13.65% - 15.09%
UNS w = 7.9% - 10.9%
UNS w = 3.58% - 4.44%

500

Gravimetric Water Content - w

600

Air-entry value = 100 kPa

 (kPa)

400
300
200
100
0

0

50

100

150

200

250

300

0,20

0,15

Fredlund and Xing
Parameters:
aF = 2286712.5

nF = 0.44746
0,10mF = 45.83315

0,05

Calibration: Chandler et al. (1992)
Experimental data
Best fit curve

0,00
-4
-3
-2
-1
0
10 10 10 10 10

2

10

3

10

4

10

5

10

6

10

Matric Suction - S (kPa) R = 30 000 kPa

 (kPa)Figure 1: Mohr-Coulomb Failure
Envelopes

1

10

Figure 2: SWCC model (Fredlund & Xing
1994)

In order to investigate the dependence of the shear strength on the matric suction,
the relationship between water content and matric suction needs to be determined.
Based on the results from SWCC test series, when the equilibrium of watercontent of the filter paper is achieved, the average gravimetric water content of thetwo soil specimens for each test is measured. Simultaneously the water content of
the middle filter paper pieces is also measured, then the corresponding matricsuction of the couple of soil specimens is interpreted from the calibration for
Whatman No. 42 filter paper reported by Chandler et al. (1992). After that, the
SWCC is gained by fitting the Fredlund and Xing (1994) model with themeasured data (Figure 2). The fitted parameters are presented in Table 4 asfollows:
Table 4: Fit Model Parameters of SWCC
Parameters
ValueA
2286712

n
0.447

m
45.83

 R (kPa)  AEV (kPa)
30000

100

In the model of Fredlund and Xing, the gravimetric water content is a function of
the variable matric suction, but the equation also can be inversed to that the matricsuction is a function of the gravimetric water content variable as Equation (3)below:
1

1 m
n
(3)
  a e wS w  eUsing Equation (3) the matric suction in soil samples at the beginning of shearing
can be deduced from the gravimetric water content measured. Hence, the shear
strength of each test can also be illustrated against the matric suction as Figure 3.
In addition, the shear stresses at failure are depicted against the applied vertical

A simplemethod tothe unsaturated
soil shear
A simple method
to determine
thedetermine
unsaturated
soil shear strength
withstrength
respectwith respect to a widerange
ofmatricsuctionto a wide range of matric suction1185

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamstress and matric suction in shear stress – vertical stress – matric suction space as
Figure 4. In the figure, the shear strength surface envelope is fitted from theobserved data. The two figures clearly evidence that the failure surface of
unsaturated soil is strongly nonlinear. It means that the shear strength parameter is
not constant on the wide range of matric suction.
V = 300 kPa
V = 250 kPa

600V = 200 kPa
V = 150 kPa

500V = 100 kPa
V = 50 kPa

 (kPa)

400
300
200
100
0

0

5000

10000

15000

Matric Suction - S(kPa)

Figure 3: Shear Strength versus
Matric Suction

Figure 4: Shear Strength Surface Envelope

Figure 5: Shear Strength versus Matric Suction
In order to determine the  b parameter, it is assumed that the  b parameter isconstant when the matrix suction is less than 500 kPa, and the test results at highmatric suction (greater than 500 kPa) are ignored. The extended Mohr-Coulomb
failure criterion in the   s plane is considered to be linear. The equation of the
failure criterion in that plane is reformulated as follow:

 f  capparent   s tanb(4)where capparent  is also the apparent cohesion parameter, equals c   V tan  .

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In plane   s , the shear stresses at failure are plotted against the matric suction,
hence the corresponding shear strength envelope of each group of the same valueof applied vertical stress are obtained by linear least squares fitting method as
Figure 5. Hence, the apparent cohesion (in the plane) and  b parameters are
deduced, their values are shown in Table 5. The average deviation of 0.636
reveals that the angle 9.8118 degrees taken average from the five values
corresponding to different group under different vertical stress applied 50, 100,
150, 200, and 250 kPa respectively is consistent.
Table 5: Shear Strength Parameter Respect to Matric Suction (S<500 kPa)
Test Series

Vertical Stress capparent 

D250
D200
D150
D100
D50

(kPa)

250
200
150
100
50
Average
Aver. Deviationtan  b

b

(kPa)

/



138.2989
112.9255
83.3161
60.441235.1096//0.18620.15830.17680.18450.1591
/
/

10.55
8.99
10.02
10.45
9.04
9.81
0.64

0

5. CONCLUSIONSIn this paper, a simple method has proposed to investigate unsaturated soil shear
strength characteristic. The testing method is a combination of the two types oftest series: the first series is used to determine the soil water characteristics curveby filter paper method; and the second series is the direct shear tests carried out on
the soil at unsaturated state with different water contents. Applying this method
enables geotechnical engineers to measure the unsaturated soil shear strength withrespect to a large range of matric suction (up to 15600 kPa).
ACKNOWLEDGMENTS
The authors appreciate the support from the Key Laboratory of Ministry of
Education for Geomechanics and Embankment Engineering and GeotechnicalResearch Institute of Hohai University.
REFERENCES
Bishop, A. W., Alpan, I., Blight, G. & Donald, I., 1960. Factors controlling thestrength of partly saturated cohesive soils. Proc.Colorado Conference, 503–532.

A simplemethod tothe unsaturated
soil shear
A simple method
to determine
thedetermine
unsaturated
soil shear strength
withstrength
respectwith respect to a widerange
ofmatricsuctionto a wide range of matric suction1187

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2013, 2013,
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Vietnam

De Campos, T. & Carrillo, C., 1995. Direct shear testing on an unsaturated soil
from Rio de Janeiro. Proceedings of The First International Conference on
Unsaturated Soils, Paris, France, vol. 1.
Crilly, S., Chandler, R. J. & Establishment, B. R., 1993. A Method of Determining
the State of Desiccation in Clay Soils. Building Research Establishment.
Chandler, R., Crilly, M., Smith, M., Smith, M. G. & BRE, 1992. A low-cost
method of assessing clay desiccation for low rise buildings. Proceedings of the
ICE - Civil Engineering, vol. 92, no. 2, 82–89.
Donald, I. B., 1956. Shear strength measurements in unsaturated, non-cohesive
soils with negative pore pressure. Proceedings of the 2nd Australia and New
Zealand Conference on Soil Mechanics and Foundation Engineering, 200–205.
Escario, V. & Saez, J., 1986. The shear strength of partly saturated soils.
Geotechnique, vol. 36, 453–456.
Fredlund, D. G., 2006. Unsaturated Soil Mechanics in Engineering Practice.
Journal of Geotechnical and Geoenvironmental Engineering, vol. 132, no. 3,
286–321.
Fredlund, D. G., Morgenstern, N. R. & Widger, R. A., 1978. Shear Strength of
Unsaturated Soils. Canadian Geotechnical Journal, vol. 15, 313–321.
Fredlund, D. G. & Xing, A., 1994. Equations for the soil-water characteristic
curve. Canadian Geotechnical Journal, vol. 31, no. 4, 521–532.
Fredlund, D. G., Xing, A., Fredlund, M. D. & Barbour, S. L., 1996. The
relationship of the unsaturated soil shear strength to the soil-water characteristic
curve. Canadian Geotechnical Journal, vol. 33, no. 3, 440–448.
Gan, J. K. M., Fredlund, D. G. & Rahardjo, H., 1988. Determination of the shear
strength parameters of an unsaturated soil using the direct shear test. Canadian
Geotechnical Journal, vol. 25, no. 3, 500–510.
Hilf, J. W., 1956. An investigation of pore water pressure in compacted codesive
soils. Technical Memorandum, Denver.
Ho, D. Y. & Fredlund, D. G., 1982. A Multistage Triaxial Test for Unsaturated
Soil. American Society for Testing and Materials.
Khalili, N. & Khabbaz, M. H., 1998. A unique relationship for χ for thedetermination of the shear strength of unsaturated soils. Géotechnique, vol. 48, no.
5, 681–687.
Nam, S., Gutierrez, M., Diplas, P., Petrie, J., Wayllace, A., Lu, N. & Muñoz, J. J.,
2010. Comparison of testing techniques and models for establishing the SWCC ofriverbank soils. Engineering Geology, vol. 110, no. 1–2, 1–10.
Öberg, A. L. & Sällfors, G., 1997. Determination of shear strength parameters of
unsaturated silts and sands based on the water retention curve. ASTM geotechnicaltesting journal, vol. 20, no. 1, 40–48.
Oloo, S. Y. & Fredlund, D. G., 1996. A method for determination of ϕb forstatically compacted soils. Canadian Geotechnical Journal, vol. 33, no. 2, 272–
280.
Vilar, O. M., 2006. A simplified procedure to estimate the shear strength envelopeof unsaturated soils. Canadian Geotechnical Journal, vol. 43, no. 10, 1088–1095.
Ridley, A. M., Dineen, K., Burland, J. B. & Vaughan, P. R., 2003. Soil matrix
suction: some examples of its measurement and application in geotechnicalengineering. Géotechnique, vol. 53, no. 2, 241–253.

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Vanapalli, S. K. & Fredlund, D. G., 2000. Comparison of Different Procedures to
Predict Unsaturated Soil Shear Strength. Advances in Unsaturated Geotechnics,
American Society of Civil Engineers, 195–209.
Vanapalli, S. K, Fredlund, D. G., Pufahl, D. E. & Clifton, A. W., 1996. Model forthe prediction of shear strength with respect to soil suction. Canadian
Geotechnical Journal, vol. 33, no. 3, 379–392.
Ye, W. M., Zhang, Y. W., Chen, B. & Zhang, S. F., 2010. Characteristics of Shear
Strength of Unsaturated Weak Expansive Soil. In Y Chen, L Zhan & X Tang
(editors), Advances in Environmental Geotechnics, Springer Berlin Heidelberg,
505–510.

A simplemethod tothe unsaturated
soil shear
A simple method
to determine
thedetermine
unsaturated
soil shear strength
withstrength
respectwith respect to a widerange
ofmatricsuctionto a wide range of matric suction1189

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Large prefabricated pile foundation,a solution for high-rise buildings in Hanoi
Bao Viet NGUYEN
National University of Civil Engineering, Hanoi, Vietnam
nbviet@sdh.nuce.edu.vn
ABSTRACT
In order to supply housing for people living in Hanoi and also the other big cities
of Vietnam where population is highly dense, buildings with multi storeys are
required. In general, most high-rise buildings were based on a strong foundation
with bored piles. Normally in construction of bored piles, soils must be drilled
and taken out of the ground. The soils and betonite slurry used in the construction
are big problems for not only the site but also for environment. The treatment
requires a lot of efforts, money and times. Foundation with large prefabricatedpiles is a solution which could overcome that issue. The solution has been applied
to 20 storeys twin buildings in Hanoi. The results show that large prefabricatedpiles could replace bored piles for high-rise building with advantages of low cost,cleaner site, lack of construction trash.
Keywords: large prefabricated piles, low cost, construction trash.
1. INTRODUCTION
Since the mid-1980s, after the "Đổi Mới" reform, Vietnam economy has
experienced rapid growth. Nowadays, Vietnam’s economy continues to expand at
an annual rate in excess of 7%, one of the fastest growing in the world. Together

(a)

(b)

Figure 1: Construction site of (a) bored piles and (b) prefabricated piles

1191

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamwith the economic growing, the population of the big cities is increasing rapidly
with very highly dense, especially in Ha Noi and Ho Chi Minh city.
In order to supply residential places for the people, a lot of multi storey buildings
are rising. The buildings with huge of self-weight and loads require a firm
foundation. Till now, foundation based on bored piles is the most common choicefor the buildings whose number of storeys higher than 15. Bored pile has large
bearing capacity because of large size, long length with toe on the expected hardsoils. But the limitation of bored pile is a lot of construction trash induced in theconstruction and so on. Figure 1a shows a swampy site with bored piles underconstruction. The poor situation obstruct significantly all the actions in site
therefore construction time would be extended. Furthermore, huge amount of soils
taken out from the ground and the used betonite slurry need to be removed out ofsite and treated as particular solid wastes.
Because of the occurrence of high ability rigs in driving pile, recently large
prefabricated pile is an alternative solution for the high-rise buildings. Foundation
based on the piles of bearing capacity up to 4,000 kN, could sustain all the loads
of a building up to 30 storeys. Applying the prefabricated piles would overcome
the limitation of the bored piles. The trash induced in the pile construction and theenvironmental consequence will be eliminated. Figure 1 illustrates the big
differences between a swampy site using bored piles and a clean site using
prefabricated piles.
2. GEOLOGICAL CONDITIONS OF HANOIHa Noi is located in the delta of HongRiver in the northern of Viet Nam. The
average elevation of Ha Noi is about+8,00m above sea level.
Stratum structure of Ha Noi might bedivided into two parts. The upper partcontain of various type of soils fromweak to pretty hard. Figure 2 illustrates
the distribution of major types of theupper part in the area of old Ha Noi.
Characteristics of soils in the upper
part are listed in the Table 1.
The lower part from about 30m below
ground level includes 2 layers a) coarse Figure 2: Distribution maps of soil types
sand, medium stiff and b) gravels within area of old Ha Noi
SPT value about 100. These layers areavailable to sustain heavy loads so pile foundation of the high-rise buildings is
usually required lay on this part.
Table 1: Description of main soil strata types in the area of old Ha Noi
Sub-soil
Name
Description
type
A
Clayed soils, up to 30m thick, PI=0.15~0.4,
A1
Single
SPT=12~15, E0=10Mpa

1192

Distribution
West Từ Liêm;Đông Anh

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layer

B
Two
layersC
Multilayers
with
weak
soil

A2
B1

B2

C1

C2-3

Clayed soils, up to 30m thick, PI=0.35~0.6,
SPT=8~12, E0=5~8Mpa
Upper layer: Clayed soils, up to 10m thick,
PI=0.15~0.4, SPT=12~15, E0>10Mpa;
Lower layer: Medium sand, medium dense,
up to 20m thick, SPT30,E0>20Mpa.
Upper layer: Clayed soils, 5~10m thick,
PI=0.35~0.6, SPT=9Lower layer: small sand, medium dense, up
to 20m thick, SPT12, E0>10Mpa;
Upper layer: Clayed soils, up to 10m thick,
PI=0.15~0.4, SPT=12~15, E0=10Mpa;
Middle layer: Organic soils, up to 10m
thick, PI>0.8, SPT=5, E0=3~5Mpa;
Lower layer: Medium sand, up to 10m thick,
SPT30, E020Mpa;
Upper layer: Clayed soils, up to 10m thick,
PI=0.35~0.6, SPT=5~8, E0=6~8Mpa;
Middle layer: Organic soils, up to 15m
thick, PI>1.2, SPT=2~4, E0=3Mpa;
Lower layer: Sandy soil, up to 10m thick,
SPT20, E015Mpa;

Hà Nội centerNorth ĐôngAnhSouth ĐôngAnh andThanh Trì; Gia
Lâm
North ĐôngAnhĐông Anh, Gia
Lâm (small
area)
Thanh Trì,South Từ Liêm3. PREFABICATED PILES FOUNDATION
The most important work in foundation design is decision of size and length ofpiles then analyses of its bearing capacity. Since mid-1990s, bored piles have beenused in Viet Nam. At that time, bored piles are the unique choice of the high-risebuildings foundation. Recently, driving ability of prefabricated piles had
remarkable steps. Occurrence of big jack-in rigs for pile driving with pressing
force up to 10,000kN has ensured that large prefabricated piles with allowablebearing capacity up to 4,000kN is completely feasible. These piles certainly could
be used for the high-rise buildings. It should be said that the rigs are complete
combination with counter-weight, cranes and mechanical moving system so thatthe pile driving could be carried out easily with highly efficient. Furthermore,
applying the prefabricated pile will eliminate most of construction trash of boredpile construction such as drilled soils and betonite mud.
To investigate the applicability of the prefabricated piles in Ha Noi area, thefollowing assumptions are used:a) Number of storeys of the buildings is 15, 20, 25 and 30;b) Total vertical loads (dead and live loads) on a floor are 15kPa; self-weight andloads of basement are 60kPa;c) Loads of winds and earthquake on foundation would be considered as 50% of
the total vertical loads.
d) Distances between piles (center to center) are 4 times of the pile size;e) Pile is rectangular and ratio of pile length and pile size is 70.
g) Nominal values of soil properties and layer thickness listed in Table 1 areapplied in analyses;
Large prefabricatedpile foundation,
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From the assumption a); b); and c), the total loading on foundation, p, could be
calculated by the following equation and the results are showed on Table 2
p = 1.5(15n + 60)(1)

Where n = number of storeys.
Table 2 Total loading acting on foundation (kPa)
Building with Number of storeys
Loading on foundation

15
427,5

20
540

25
652,5

30
765

Based on assumptions e) and g), allowable bearing capacity, Qa, of prefabricatedpiles are estimated according to equation A.4 in Vietnamese code TCXD 2051998, “Pile foundation – Specification for design”. The results showed inTable 3.

Qa 

q p . Ap  u  f i .l i

(2)

FS

Where qp = soil resistance at pile toe tabulated depend on soil type and depth;
Ap = cross section area of pile;fi = soil friction at ith segment tabulated depend on soil type and depth;li = length of ith pile segment;u = perimeter of pile cross section;
FS = factor of safety = 2.
According to assumption d), the minimum area, Amin, required for one pile withsize of 35, 40, 45 and 50 are 1.96, 2.56, 3.24, 4.00 sqm, respectively. In order toindicate which size of piles is available for foundation of the high-rise buildings,
the bearing capacity of piles should be showed also in term of Qaua = Qa/Amin. The
term expresses allowable bearing capacity of the pile foundation on a unit of area
so that it is easy to compare with the loads of the buildings tabulated in Table 2.
The values of Qa and Qaua are tabulated in the Table 3.
Table 3 Allowable bearing capacity of the piles Qa (kN) and Qaua (kPa)
Pile size(cm)
Sub-soil
type
A1
A2
B1
B2
C1
C2-3

1194

35x35

40x40

45x45

50x50

Qa

Qaua

Qa

Qaua

Qa

Qaua

Qa

Qaua

1260
710
1420
950
950
780

643
362
724
485
485
398

1730
950
1970
1300
1430
1180

676
371
770
508
559
461

2620
1990
2970
2380
2360
1630

809
614
917
735
728
503

3250
2550
3630
2980
2970
2060

813
638
908
745
743
515

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To assess applicability of the pile foundation to the high-rise buildings, feasibility
ratio, Rfea, defined as a ratio of allowable bearing capacity of pile foundation on aunit of area, Qaua, and total loading acting on foundation, p.
Rfea = Qaua / p(a) Buildings with storeys of 15(b) Buildings with storeys of 20(c) Buildings with storeys of 25(d) Buildings with storeys of 30(3)

Figure 3: feasibility ratio of prefabricated piles
The values of the feasibility ratio, Rfea, are illustrated in Figure 3 for the high-risebuilding of 15, 20, 25, 30 storeys. Based on value of Rfea, it might be divided theapplicability degree into three ranges: a) high applicability with Rfea>=1.0; b)
medium applicability with 1.0>Rfea>=0.8 and, c) low applicability with Rfea<0.8.
Figure 3a showed that 15 storeys buildings could use most of pile sizes for all
types of soil strata. In case of A2, C2-3 soil types, pile with size of 35x35cm and40x40cm might be used if thickness of the soft soils in the sites is thin enough so
the pile toe can reach to the stiff sand layer below.
Value of Rfea in Figure 3b&c indicated that for 20 or 25 storey buildings, theapplication of the pile in sites of C2-3 and A2 soil types needs to be considered
carefully. A1 and B1 soil types are the 2 stiffest then they are available for all thesize of piles. The other types of soil are suitable for pile with size of 45x45cm and
50x50cm.

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The applicability of the piles for 30 storeys buildings are showed in Figure 3d.
Because of very heavy loads, only pile size of 45x45cm and 50x50cm could be
used for soil types of A1 and B1. It is considerably risk if soil types are A2 andC2-3 whatever the pile sizes are. The piles with size of 45x45cm and 50x50cm
might be used for B2, C1 soil types with careful consideration.
4. CASE HISTORY

A project of 20 storey twin buildings located in
Gia Lam district area is one of the first projects
using large prefabricated pile. Strata at the site
may be classified into B2 type in the Table 1,
the details showed in ࢚࣮ࣛ! ཧ↷ඖࡀぢࡘ࠿ࡾࡲࡏࢇࠋ.
Foundation of 45x45cm piles with effective
length of 30m was applied for the buildings.
Based on the above mentioned approach andresults of static load test, the allowable bearing
capacity with FS=2.0 are 2,000kN and 1,700kN
respectively. Structural bearing capacity of thepile with high strength concrete is of 5,000kN.
Structural analysis results showed that dead andlive loads of about 520MN. The vertical load
plus wind and earthquake loads transfer to 386
piles of the foundation. The maximum loading
acting on one pile is about 1,500kN which is insafety range of 1,700kN.
It should be noted that with total floor area of
41,440sqm, the total vertical loading acting on
foundation is about only 12.55kPa much smaller
than the proposed value of 15kPa. In addition,
the feasibility ratio is about 1.66 much greaterthan the value evaluated in part 3, Figure 3b.
Furthermore, the assumption c) (wind andearthquake load is about 50% of verticalloading) seems to be conservative for 20 storey
buildings (the loads of analysis results is only
about 10% of the vertical loads).
All the above results have proved theapplicability of the piles in term of bearing
capacity. On the other hand, the serviceability
conditions must be also satisfied. The estimatedsettlement is even about 10cm but when most of
concrete and brick works already finish (70%
total loads), the measurement settlement was
about 1.0cm. However, it should be noted thatthe measurement works started a little late, after
the 4th floor finish.
Generally, the application of prefabricated pile

1196

Figure 4: Twin buildings

Figure 5: Soil strata of thetwin buildings

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foundation to the 20 storey twin buildings in Ha Noi was success. The results
would open an alternative approach for high-rise foundation with number ofadvantages such as environmental and economic efficiency, as well as
construction time reduced.
Pile driving activities in the site of the twin buildings showed that occasionally thepile toe could not reach to the expected depth even the jack pressure was large
enough to destroy the pile head. The cause may be the sandwiched sand layers. If
a soft layer is just below the pile toe then the settlements of the buildings may be
increase significantly. Hence, in case of sandwiched sand layers, it is necessary toconsider carefully application of the prefabricated pile foundation.
5. CONCLUSIONS

The analysis results of both hypothetic and practice indicated that the large
prefabricated pile foundation could be applied to the high-rise buildings up to 30
storeys. In case of the 20 storeys twin buildings, the 45x45cm prefabricated piles
saved 20% of budgets for foundation. In addition, this approach did not make lotof construction trash like bored pile construction so that the trash treatment was
not necessary. Last but not least, the construction site was pretty clean therefore
the construction works of foundation could be carried out smoothly.
In Ha Noi, soil types of A1 and B1 is most suitable for prefabricated pilefoundation of buildings up to 30 storeys. In case of B2, C1 soil types, theapplicability of the piles for buildings up to 25 storeys is highly reliable. If theloads are heavy like buildings of 30 storeys, then pile sizes of 45x45cm and
50x50cm are required with carefully consideration. Buildings of 15 storeys andbuildings of 20 storeys could be settled on C2-3 and A2 soil types, respectively,
with large size of pile (45x45cm and 50x50cm). When the loads become greater,C2-3 and A2 is not much suitable for the piles.
It should be carefully considered to apply the prefabricated pile foundation in caseof soil strata has sandwiched sand layers which could obstruct driving pile to thedesign locations.
REFERENCES

Geotechnical and Construction Engineering Institute, 2010. Calculation report of
the twin buildings. Unpublished documents in Vietnamese.
Inspection testing and environment JSC, 2012. Settlement monitoring report of thetwin buildings. Unpublished documents in Vietnamese.
Nguyen Huy Phuong, et al., 2004. Collect and verify the existing documents, tostudy and complement for mapping the distribution of soft soils in Hanoi. Generalreport of key topics of Hanoi, TC-ĐT/06-02-03, Ha Noi, Viet Nam.
Vietnamese code TCXD 205-1998. Pile foundation – Specification for design.

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solution fora high-risebuildings
in buildings
Hanoi in Hanoi
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New Technologies for Urban Safety of Mega Cities in Asia

Sustainability in the concrete industry
for construction of mega cities1Kiên TONG1, Thành LE2 and Lanh PHAM3
National University of Civil Engineering, Vietnam
kientt@nuce.edu.vn
2
Ministry of Construction, Vietnam
3Construction Technical College No 1, Vietnam

ABSTRACTIn the last 150 years, concrete has become one of the most widely used building
materials for construction of large cities in the world. The use of concrete has asignificant impact on sustainability. Environmental responsibility is certainly partof it, but any form of construction must also be socially beneficial andeconomically viable. A building material, to be truly sustainable, must address all
three of these criteria. This paper presents some ideas on using raw materials forsustainable development in the concrete industry. The first is reusing construction
demolition waste as recycled aggregate to form an environmental- friendly
concrete. The second is using industrial wastes (Fly ash, Blastfurnace slag, glass,silica dust, steel slag, etc.) as replacement materials to both cement andaggregate for concrete. These more sustainable concrete are expected to play a
key role in construction of safer mega cities in the coming time as it can help to
cut down large volume of carbon dioxide emitted from cement production andalso reduce pollution from exploitation of natural raw materials.
Keywords: Recycled Aggregates (RAs), Construction Demolition Waste (CDW),
Recycled Concrete Aggregate (RCA), Sustainable Concrete, Fly ash (FA).
1. SUSTAINABLE BUILT ENVIRONMENT CONCRETE
There are three general pillars of sustainability in regard to economic,
environmental, and social aspects (Tom et al., 2012). When activities are
sustainable, no pillar is ignored; instead, a workable balance between the three
aspects must be found. Together, the three pillars form what is commonly called
the “triple bottom line”. This concept can be expressed graphically as shown in
Figure 1.
Concrete has become one of the most widely used building materials on earth.
Throughout history, the use of concrete as a building material has contributed
significantly to the built environment (Tarun, 2008). Annual global cement
production has reached 3.2 billion tonnes, and is expected to increase to some 3.5billion tonnes per year in 2015 (Martin and Verein, 2011). According to Metha P.
K. (Mehta, 2002), if a typical concrete mix contains about 12% cement, 8%1199

October 2013, Hanoi, Vietnam

mixing water and 80% aggregate by mass then in addition to 3.2 billion tonnes of
cement used worldwide, the concrete industry is consuming 21.3 billion tonnes ofsand and rock, and 2.2 billion tons of mixing water annually. In total, theconcrete industry, which uses 26.7 billion tonnes of raw materials each year, isthe largest user of natural resources in the world. Associated with concrete
industry is the inevitable carbon dioxide emissions estimated to be responsible for
5 to 7% of the total global production of carbon dioxide.

Figure 1. Three general pillars of sustainability (Tom et al., 2012)
The long-term approach to lower the enviroment impact of using any materials indevelopment of sustainable concrete industry is to reduce rate consumption of
concrete. In the short-term, we must begin practicing industrial ecology forsustainable industrial development (Mehta, 2002). The practice of industrial
ecology involves recycling the waste products of one industry by substituting
them for the virgin raw materials of another industry, thereby reducing theenvironmental impact of both.
A sustainable concrete structure is commonly fabricated to ensure that the total
environmental impact during its life cycle, including its use, will be minimal(Tarun, 2008). Sustainable concrete should have a very low inherent energy
requirement, be produced with little waste, be made from some of the mostplentiful resources on earth, produce durable structures, have a very high thermalmass, and be made with recycled materials.
Buildings that are constructed to be both durable and environmentally friendly
often lead to higher productivity because the buildings generally lead to better air
quality and therefore higher productivity.
For the sustainability of the cement and concrete industries, water and portland
cement should be used less and blended cements and organic chemical
admixtures should be used more (Mehta, 2002). Bearing in mind that thedevastation of air is a global problem, regardless of the locality in which thepollution is created.

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2. SUPPLEMENTARY CEMENTITIOUS MATERIALSThe use of cement substitution and of recycled aggregate substitution is being
acknowledged recently by many countries in over the world. To date, concretebuilding solutions for green credits through a level of cement reduction by using
supplementary cementitious materials (SCMs) such as fly ash or blast furnaceslag. Portland cement is not considered as an environmentally friendly material,
because its manufacture creates greenhouse gas emissions. Therefore, engineers
must reduce the use of portland cement in concrete (Malhotra, 2004). We must
use more blended cements rather than portland cement clinker by blending
clinker with other puzolan materials or use SCMs. This also leads to reduce theneed of raw materials for manufacturing cement.
2.1. Supplementary Cementitious Materials
A significant proportion of concrete produced contains SCMs as part of the total
cementitious component or binder (CCAA, 2010). The three types of SCMs
commonly used are puzolan materials such as: ground granulated blast-furnace
slag (slag), fly ash and amorphous silica. When blended with portland cement incertain proportions, they impart many beneficial properties to concrete. By
reducing the amount of manufactured cement required in a given concrete mix,
the use of SCMs further reduces concrete’s environmental impact. SCMs also
lead to better economic outcomes for concrete construction - being industrial byproducts, they can be produred at a lower cost than cement.
Ground granulated blast furnace slag (GGBS): Slag is a by-product of the
manufacture of steel in a blast furnace. It is formed simultaneously with iron;when cooled rapidly it produces a non-metallic product that can be ground andused as an SCM in concrete. In Vietnam, slag has been used in quantities of up to
60% of the mass for slag cement, 20-40% for blended cement or sulfate ressistantcements, 50-60% for low heat cements (VIBM, 2008). The use of GGBS as apartial replacement of cement revealed the different behavior of compressive
strength development. Our recent research results on Ultra-High Performance
Concrete (UHPC) using GGBS (Thang et al., 2013) revealed that the compressive
strength of UHPC was in excess of 150MPa with using 20% of GGBS undernormal curing and up to 30% with steam curing. When GGBS was used, thecompressive strength of the sample curing at 20oC increased slowly at early age
but strength gained faster at 90 days and did not match that of the 90oC curing
specimens. After 90 days, under 90oC curing, compressive strength of all UHPC
samples could reach 150 MPa with the GGBS replacement up to 50% (fig. 2).
Fly ash (FA): is one of the residues generated in the combustion of coal. FA used
as an SCM in concrete is recovered from the electrostatic precipitators before thechimneys in coal-fired power stations. Fly ashes damage the environment when
illegally dumped, occupy large volume when disposed of in landfill sites, andcould be harmful to human and animal health. The recycling of FA in beneficial
products would therefore be useful to alleviate its aforementioned adverse
implications. Recycling FA in construction, including concrete, is a major
approach to tackle this problem. When replacing cement, FA could indirectly
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reduce the CO2 emission linked to cement production as well as decrease landfill
area.

Figure 2. Effect of GGBS on compressive strength of UHPC, w/b = 0.16, (a)20±20C, (b) 90±50C (Thang et al., 2013)
In Vietnam, FA is typically used up to 40% of the mass of the total cement, 2040% for blended cement or sulfate resistant cements, 20-30% for low heat
cements (VIBM, 2008). The research results of a high strength concrete(compressive strength of above 80 MPa) investigated in National University of
Civil Engineering (Pham et al., 2011b; Tong, 2009) showed that high strength
concrete can be manufactured using high content of fly ash as a cement
replacement for the structures in Vietnamese marine environment. 35% fly ash
added in a 80 MPa compressive strength concrete showed more advantageous inmechanical properties comprising flexural strength, water permeability, chloride
penetration and abrasion resistance, when being compared with a typical concrete
which is usually used for the structures in Vietnamese marine environment. The
use of this concrete probably helps extend the service-life of the infrastructures
and also helps reduce a large amount of an industrial waste (Fly ash) discharged
from Vietnamese thermal power plants. This will be able to improve all three
aspects of a sustainable construction which comprises economy, natural resourceand environment.
Amorphous silica: covers a range of products, from a naturally-occurring material
to by-products of the silicon and ferrosilicon production processes. The latter issometimes referred to as silica dust, silica powder, silica flour or microsilica. The
name most commonly used is silica fume (SF). In Vietnam, silicafume istypically used 5-10% or up to 15% of the mass of the total cement for specificapplications, e.g. high-strength concretes, UHPC. The total cement replacement
by using a blend of GGBS and SF can reach to 55% (45% GGBS and 10% SF) in
UHPC, the compressive strength of all samples in excess of 150 MPa under 90oC
curing and at 90 days (Thang et al., 2013). Another amorphous silica used in
Vietnam is rice husk ash (RHA), which is come from an enormous quantity of
waste discharged from Vietnamese rice paddy has been processed to become amineral admixture for using in concrete products. For example, 20% rice husk
ash has been utilised to partially replace cement in a 70- 90 MPa high strength
concrete or in lightweight foamed concrete with 4-6 MPa compressive strengthand 700-900 kg/m3 density (Pham et al., 2011a).

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2.2. New types of binders
New types of binders and material concepts Alkali activated cements (orGeopolymer) is a name used for a large group of binders which solidify after theactivation of a reactive solid in a highly alkaline environment. The setting andstrength development can mainly be ascribed to polycondensation reactions
which form three dimensional networks of amorphous inorganic aluminosilicates.
Geopolymers can be produced on the basis of natural sources of aluminosilicates,e.g. kaolin, or on the basis of waste materials like y ash, slag. The characteristics
of geopolymer binders strongly depend on the source material and the activation
conditions. Possible advantages of these materials can be a high early and/or nal
strength, a high resistance against chemical attack, the good passivation ofreinforcement, a very dense microstructure and heat resistance (Schneider et al.,2011). According to Davidoits (Davidovits, 2002), geopolymer concrete canreduce 26-45% of green house gas CO2 compare to conventional concrete. Thisdue to the production of 1 tonnes cement generates 0.55 tonnes of CO2 and needs
the burn of carbon-fuel into 0.42 tonnes of CO2. To simplify: 1T cement = 1T
CO2. However, the production of 1 tonne of Geopolymeric cement generates
0.180 tones of CO2, from combustion carbon-fuel, compared with 1.00 tones of
CO2 for Portland cement. Geo-polymeric cement generates six times less CO2
during manufacture than Portland cement. This simply means that, in newly
industrialising countries, six times more cement for infrastructure and building
applications might be manufactured, for the same emission of green house gas
CO2. Since January 2013, some of preliminary investigations have been
conducted into geopolymer materials at National University of Civil Engineering.
These investigations have been based around geopolymer mortars using low-Ca
FA and GGBS in Vietnam as the sole pozzolanic solids, the type of alkaline
activator is a combination of NaOH and Na-silicate solution. The compressive
strength of mortar using recyled fine agregates can reach 50-70Mpa for binder
geopolymer based on GGBS under normal curing but only give 10-30Mpa forbinder geopolymer based on FA under dry curing at 700C depen on alkali dosage
was varied from 7.5% to 15% and Alkali modulus in the activator solution.
Novacem is reported as a cement based on magnesium oxide and hydrated
magnesium carbonates (Novacem, 2010). According to the inventors of thisbinder, the raw material is based on magnesium silicates which are globally
available in large quantities. During hardening, Novacem absorbs carbon dioxidefrom ambient air. So it may be reduce invironment impact of concrete industry.
Calcium sulfoaluminate (CSA) cements are binders mainly based in the phases
yeelimite (C4A3S'), belite, CAF and gypsum in varying ratios (Schneider et al.,2011). The solidication of these binders is mainly based on the formation of
ettringite and CSH phases. Due to the lower temperatures and the lower content
of calcium, the specic CO2 emissions of CSA cements are lower than those of
Portland cement clinker.

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3. RECYCLING MATERIALS FOR ENVIRONMENTAL-FRIENDLY
CONCRETE
Recycling concrete is not an end in itself, a full Life Cycle Assessment of theconcrete structure, including the recycling phase at the end of its life, is required
to assess the overall sustainable credentials of the structure (CCANZ, 2011). As
regards the concrete manufacturing phase, much effort has gone into reducing theenvironmental footprint of cement manufacture. Transportation and delivery at
all stages of concrete production is the second greatest source of impact. So that,recycling concrete waste for new concrete tends to produce environmental benefit
by preserving natural aggregate and water, a finite resource.
It is estimated that 1 billion tonnes of construction and demolition waste (CDW)
are generated annually worldwide. Whether CDW originates from clearing
operations after natural disasters (e.g., major earthquakes) or from humancontrolled activities, the utilization of such waste by recycling can provide not
only economically advantages but in addition local recycling minimizes
environmental impact by reducing the carbon footprint, embodied energy, andemissions and enhances social products by reducing the need for landfills and theextraction of nonrenewable raw materials. Achieving this goal ensures that abalance is struck among the economic, environmental, and social factors. This isespecially efficient in regions of high population density where the limitation ofavailability of construction materials often leads to cost-effective options forrecycling concrete.
Within a life cycle analysis, the use of recovered concrete can lower overall
environmental impact:• Failing to use recovered materials increases landfill and associatedenvironmental and health costs;• Failing to use recovered materials means virgin materials are used instead;• Recovered concrete is generally inert;• In some cases, transportation needs for recycled concrete can be lower thanvirgin materials (often not located in urban development areas) and as such
fuel consumption, CO2 emissions and road and vehicle use can be reduced.
However, processing technology for recovery of concrete should consider
possible air and noise pollution impacts as well as energy consumption, although
there is little difference to natural aggregates processing.
3.1. Reusing water and aggregate in concrete mixture
The use of water in concrete production has been a source of debate and researchover many years. The acceptability of recycled water for use in concrete isdecided by its effect on workability, strength and durability of the concrete. Oneof the most common methods of recycling water in the concrete batching process
is to use water run-off or slurry from concrete production operations (CCAA,
2010). If the batching plant has a reclaiming facility, aggregates can be reclaimed
from returned concrete. Unused concrete which is returned to a plant in a plastic

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state goes through a separation process washing cement slurry from theaggregates, figure 3.
Trucks returning from the site to be washed out discharge into ‘concrete
reclaimer’ where the aggregates are then re-graded from the liquid fines, and areavailable for use in freshly batched concrete. Recycling washout material reduces
the amout of fresh water required for mix operations whilst minimising the amoutof solid material which has to be disposed of.

Figure 3. Typical system for recycling wash water/aggregate recovery
3.2. Reproduce hardened concrete and construction demolition waste into
recycled aggregate
In many countries, recycled concrete aggregates have been proven to be practicalfor structural concretes. A number of manufactured and recycled aggregate plants
are readily available in over the world as well in Vietnam (Tong, 2011). We havecarried out some research projects regarding CDW and found that recycledconstruction demolition waste from concrete and masonry can be utilised as
natural aggregates as well as natural materials for all subgrade, base and subase
layers of road foundation without cement treated (Kien et al., 2013; Tong, 2011).
When using recycled fine aggregate (RFA) for lower base layer of the highperformance pavement structures, it should be reinforced with 7.5% cement for
RFA from concrete debris and 10.5% cement for RFA from masonry debris.
10.5% and 12.5% cement respectively from concrete and masonry debris, whichusing RFA for upper layer of the high performance pavement structures and thebituminous pavements.
In the recycled aggregate plants, both coarse recycled aggregates and finerecycled aggregates are produced and/or dredged for use in new concrete. Thisuse makes up only a small portion of the total extractive industry output, most ofwhich is used in asphalt, road base, civil works and site works. Currently, mostconcrete producers utilise aggregates sourced from the nearest quarries, and theirconcrete mixes design to suit with the aggregates. This leads to a lower overall
cost, lower environmental impact due to minimising transportation, and often
underpins the local economy, especially in rural areas. A fully system for
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recycling aggregate is showed in figure 4. This can reduce up to 80% freshwaterusing in the plant and recovery about 90% CDW into high quality recycled
aggregate.

Figure 4. Fully diagram of the recycled aggrgate washing plant, M2500 fromconstruction demolition waste (source: www.cdeglobal.com)
For example, in the UK, the cost of using 10,000 tonnes recycled concretederived aggregate as a substitute for limestone aggregate, see Table 1 (Tang,2008). A direct saving of £89,800 is noted. It mainly arises from the reduction intransportation costs. Significant environmental benefits are also achieved, i.e. a
reduction of 31.5 tonnes of CO2 emission by avoiding the long distance deliveryof importing limestone from North Wales. Otherwise, it will take 43 trees
approximately 100 years to offset this amount of CO2.
Table 1. Economic and environmental benefits from using recycled demolition
aggregate

Total cost of using quarried
limestone (10,000 tonnes)
Gate price, ₤Total cost of using recycled Direct saving
aggregate (10,000 tonnes of from using
concrete rubbles as coarse
recycledaggregate)
aggregate

Transportation cost
Gate
In
In
Total CO2 priceTotal CO2
CO2,
Cost, travel emissi cost, Cost, travel emissi cost, ₤ tonne
Min Max₤₤ distance on,₤ distance, on,, mile tonne
mile tonne
40,00₤109, ₤122,6
47,059₤59,7 20,00
>₤89,
0
38
8,824
6.5
31.5
500
00
+4000
00
0
800
+20,0

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00
There are several barriers to recycling CDW. The most significant barrier is thepotential inability on the part of project managers and solid waste authorities to
identify markets for the debris. Another barrier is the difficulty in accurately
characterizing CDW, CDW is highly variable in both content and quantity. Thisvariability is due to the nature of the waste, the dispersion of construction anddemolition activities, inconsistent waste management regulations, range ofdisposal options, and the variance in cost of disposal options.
5. BARRIERS TO DEVELOP SUSTAINABILE CONCRETE INDUSTRYIN VIETNAMIn Vietnam, natural material sources are commonly availabe, exploration tax ofthe resources is relatively low meanwhile there are not many economic policies toencourage investors and concrete producers invest on research and production ofsustainable concrete. There is no clear plan for disposal CDW area separately andthe discharge of leftover fresh concrete in concrete plants.
Building standards are another institutional barrier that discourages the use ofrecycled materials. Vietnam has not specification requirements for raw materials
in processing sustainable concrete, particularly reused and recycled materials.
Some out-of-date codes specify the use of particular materials and mixture
proportions for a job rather than specifying a particular standard of performance.
There are no standards for specification requirements, checking and taking overthe buildings which use recycled concrete structures.
A third institutional barrier is lack of a holistic approach in engineering education
and research. Currently, structural design teaching at universities is mostly
focussed on technical and economic issues. Environmental factors such as global
warming and social factors such as noise and dust pollution are largely ignored.
The design/selection by civil engineers on construction materials, structure styles
and methods of construction/ maintenance clearly has a significant effect on theenvironment and society. The shift from reductionistic to holistic construction
practices must begin by reforming the present system of education and research in
the fields of concrete science and technology. Sustainable development of theentire concrete construction industry will have to proceed for a better future in
construction of mega cities.
6. CONCLUSION
There are some ways discussed to gain sustainability for concrete: reusing
construction demolition waste as recycled aggregate to form an environmentalfriendly concrete; and using industrial wastes (Fly ash, Blastfurnace slag, glass,silica dust, steel slag, etc.) as replacement materials to both cement and aggregate
for concrete. The more sustainable concrete are expected to play a key role inconstruction of safer mega cities in the coming time as it can help to cut down
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large volume of carbon dioxide emitted from cement production and also reduce
pollution from exploitation of natural raw materials.
Development of sustainability in the concrete industry to build more sustainablemega cities really needs the support from policy makers and governments.
Unnecessary restrictions or barriers on the use of recycling materials should be
removed. Crafting precise specifications, taking into account sustainability
requirements, educating structural engineers, designers, contractors, and theconstruction community on new construction materials and technologies, andenforcing contract plans during construction, are the keys to the wide utilisation ofsustainable concrete.
REFERENCES
CCAA. 2010. Sustainable Concrete Materials. Briefing 11 April 2010, Cement
Concrete & Aggregates Australia [Online]. Available: www.ccaa.com.au[Accessed 2012].
CCANZ. 2011. Best Practice Guide for the use of Recycled Aggregates in New
Concrete. Cement & Concrete Association of New Zealand.
DAVIDOVITS, J. 2002. Environmentally Driven Geopolymer Cement
Applications. Geopolymer Institute, 02100 Saint-Quentin, France.
KIEN, T. T., THANH, L. T. & LU, P. V. 2013. Utilisation of construction
demolition waste as stabilised materials for road base applications. In: Theinternational Conference on Sustainable Built Environment for Now and the
Future, 26 -27 March 2013, 2013 Hanoi, Vietnam. Construction publishing house,
Page 285-293.
MALHOTRA, V. M. 2004. Role of supplementary cementing materials andsuperplasticizers in reducing greenhouse gas emissions. In: Proc.,ICFRC Int. Conf.
on Fiber Composites, High-Performance Concrete, and Smart Materials, Indian
Institute of Technology, 2004 Chennai, India. 489-499.
MARTIN, S. & VEREIN, D. Z. 2011. New technology in cement manufactory.
Global Cement Magazine.
MEHTA, P. K. 2002. Greening of the concrete industry for sustainable
development. ACI Concrete International, Vol. 24 (7), 23–28.
NOVACEM, L. 2010. NovacemCarbon Negative Cement: Presentation for SCI
25
November
2010[Online].
Available:
http://novacem.com/wpcontent/uploads/2010/12/20101125-Technical-update.pdf [Accessed 2011].
PHAM, H. H., BUI, D. D., TONG, K. T., LE, T. T. & NGUYEN, T. V. 2011a.
Development of sustainable building materials at national university of civilengineering of Vietnam. In: The international Conference on Innovation andsustainable construction in developing countries, 1 -3 November 2011, 2011aHanoi, Vietnam. Construction publishing house, Page 201-206.
PHAM, H. H., TONG, K. T. & LE, T. T. 2011b. High strength cncrete using fly
ash for structures in Vietnamese marine environment for sustainability. In: Theinternational Conference on Innovation and sustainable construction in developing
countries, 1 -3 November 2011, 2011b Hanoi, Vietnam. Construction publishinghouse, Page 173-177.

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SCHNEIDER, M., ROMER, M., TSCHUDIN, M. & BOLIO, H. 2011.
Sustainable cement production- present and future. Cement and Concrete
Research, Vol. 41, 642–650.
TANG, K. K. 2008. Precast concrete paving products made with recycled
demolition aggregate Doctor of Philosophy, University of Liverpool (English).
TARUN, N. R. 2008. Sustainability of concrete construction Practice periodical
on structural design and construction, ASCE May 2008, pages 98-103.
THANG, N. C., TUAN, N. V., THANH, L. T., HANH, P. H. & GUANG, Y.
2013. Ultra High Performance Concrete using a combination of Silica Fume and
Ground Granulated Blast-Furnace Slag in Vietnam. In: The international
Conference on Sustainable Built Environment for Now and the Future, 26 -27
March 2013, 2013 Hanoi, Vietnam. Construction publishing house, Page 303-309.
TOM, D. V., PETER, T., GARY, F., DAVID, G., MARTHA, V. & EMILY, L.
2012. Sustainable concrete pavements: A manual of practice. National Concrete
Pavement Technology Center, Iowa State University
TONG, T. K. 2009. Fine aggregate concrete for the structures in Vietnamese
marine environment. Master of Engineering, National University of Civil
Engineering, (In Vietnamese).
TONG, T. K. 2011. Studying the posibility of recycling demolition watste toproduce construction materials. Final report of University project, National
University of Civil Engineering, (In Vietnamese).
VIBM. 2008. Using artificial mineral materials for manufacturing of portland
cement blended and special cements. Vietnam Institute of Building Materials, (InVietnamese).

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Slump control of fresh concrete by re-dosing
polycarboxylic based superplasticizer andcomparison with naphthalene based
Ram Hari DHAKAL1*, Pitisan KRAMMART2, Chalermchai
WANICHLAMLERT3 and Akarawit NARONGKUL2
1Graduate Student, School of Civil Engineering, Sirindhorn International Instituteof Technology(SIIT), Thammasat University, Pathumthani, Thailand*e-mail of corresponding author: dhakalramhari@gmail.com
2Department of Civil Engineering, Rajamangala University of Technology
Thanyaburi, Pathumthani, Thailand
3Construction and Maintenance Technology Research Center, SIIT, Thammasat
University, Pathumthani, Thailand

ABSTRACTThis research was made to solve slump loss problem of ready mix concrete during
delivery time. Research was focused to find the possibility of slump control in
concrete by adding second dose of superplasticizer (SP), after it losses certain
percentage of slump. Concrete mix designed for test specimen was prepared withthe paste (ratio of volume of cement to volume of void in the aggregate) contain of
1.1 and 1.2, water to cement ratio 0.63, initial dose of SP 0.5% forNaphthalene(NP) and 0.18% for Polycarboxylic(PC) based by weight of cement.
Re-dosing of SP was done in 30, 60, 90 minutes respectively. The research wasconcluded that addition of second dose of SP is possible to regain the slump infield and there is certain relation between percentage slump loss and second doseof SP. But for addition of second dose, NP based SP seems easier practically thanPC based. It is also found that there is not any adverse affect on compressive
strength of concrete (28 days) due to addition of second dose of SP in concrete.
Keywords: Concrete, Naphthalene, Polycarboxylic, Re-dosing, Slump

1. INTRODUCTION
The workability of fresh concrete can be defined by many ways. Workability is
the ability of a fresh concrete mix to fill the form/mold properly with the desired
work (vibration) and without reducing the concrete's quality. Workability ofconcrete is defined as the amount of useful internal work necessary to produce fullcompaction. [1] The ASTM C 125-00 defines workability of the concrete as “thatproperty determines the effort required to manipulate a freshly mixed quantity ofconcrete with the minimum loss of homogeneity” [2].
The superplasticizer are chemical additives which are introduced to concrete mix
to reduce amount of water in the mix, hence reduce capillary porosity of thehardened cementations materials and to maintain a specified workability of fresh

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2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnamconcrete for reasonable period of time even at low water cement ratio. [3] This isachieved without undesirable side effects such as excessive air entrainment or set
retardation. Major three types of raw materials used in SP, are Sulfonatednaphthalene formaldehyde (SNF), Sulfonated melamine formaldehyde (SMF) andPolyacrylates. The dispersing mechanism for water reducing admixtures (i.e.
Lignosulfonate based) and SP (Naphthalene and Melamine based) is based on
Electrostatic stabilization shown in Figure 1 [4]Figure 1: Electrostatic stabilization

Figure 2: Steric hindrance

The dispersing mechanisms for polycarboxylate and comb polymers are based onelectrostatic stabilization with Steric hindrance together shown in Figure 2 [4].
Ready mix concrete is ordered based on workability (slump) and strength class.
SP is added in concrete which make concrete workable at ready mix factory to get
desired slump. In practice workability is a desirable property of concrete at sitewhen pouring and compacting it, but during fresh stage it loses workability withelapsed of time. In case of long haul involved specially in delivering ready-mixed
concrete to the site it is needed to retain the workability for longer period.
Sometimes the concrete batch does not meet the job requirement when it reaches
to the construction site and leads to reject.
There are three possible options to retard or restore the slump loss in concrete;making high initial slump, re-tempering with water and re-tempering with SP after
certain interval of time. Making initial slump high is not a reliable option, because
it is usually not possible to estimate the time needed before discharge of concrete,
re-tempering with water significantly reduces the strength of concrete even though
the slump is restored, re-tempering with SP can restores the slump with lessadverse effect on concrete properties [5, 6]

2. MATERIALS AND TEST METHODS
2.1 Materials
Cement: Ordinary Portland cement Type I was used. The physical and chemicalcompositions of cement are shown in the table 2

Ingredients
CaO (%)

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Table: 1 Chemical/ Physical Properties of Cement
Value
Ingredients
64.28

K2O (%)

Value
0.48

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SiO2 (%)
Al2O3 (%)
Fe2O3 (%)
MgO (%)Na2O (%)

20.35
5.02
3.18
2.03
0.20

SO3 (%)
Specific Gravity
Blaine Finesse (cm2/gm)
Loss of Ignition (%)

2.92
3.1
3440
1.42

Aggregate: Normal weight fine and course aggregate was used in this research.
The natural river sand passing through sieve no. 4 and naturally found in Thailand
was used as the fine aggregate and crushed limestone with the maximum size of
25mm conformed to ASTM C 33 was used as the coarse aggregate. The physicalproperties of coarse and fine aggregates (gravel and sand) are shown in the table
2.
Table: 2 Physical Properties of Aggregate
Value
Remarks
Physical Properties
GravelSand
Specific gravity
2.71
2.6
Fineness modulus
7.98
2.45
Water absorption (%)
0.7
1.06
Water: Tap water available in civil engineering laboratory SIIT, Thammasat
University was used.
Chemical Admixture (Superplasticizer): NP based, brand name MXT, and PC
based, brand name ADVA 208 SP commercially available and widely used in
Thailand was used.
2.2 Mix Proportion
The water cement ratio of mix was 0.63 and the paste contain and of mix was 1.1
and 1.2. Initial dose of SP was 0.55% and 0.18% by weight of cement for NP
based and PC based respectively. The minimum void in aggregate was found infor sand/gravel ratio of 0.42 and was 23.5.
2.3 Concrete Mixing Procedure
The drum type concrete mixture was used. Initially, cement, course aggregate andfine aggregate were weighted and put in the mixture and dry mixed for one
minute. Then weighted amount of water was added and mixed for one minute.
Finally the weighted amount of SP was added and mixed for two minutes. Total
mixing time was around four minute.
2.4 Slump Measurement and Re-dosing of SP
The slump was measured immediately after the mixing procedure was finishedand recorded as the initial slump. Then the concrete was kept in the tray with theplastic cover to prevent loss of water by evaporation. Then the sample of concrete
was used to measure the slump value at stipulated time of 30, 60 and 90 minutes
respectively. The measured slump was recorded as the slump before re-does.
Before measuring the slump, sample was mixed for two minutes to make ithomogenous.
Then guess weighted amount of SP was added to the concrete as a second doseand mixed for two minutes to make it homogenous. Again slump was measured
Slump
Controlof Fresh
Concretepolycarboxylic
by Re-dosing Polycarboxylic
Based Superplasticizer an
Slump controlof freshconcreteby re-dosing
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dComparison
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October
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Vietnamand recorded as slump after second dose of SP. The process was repeated until theoriginal slump was regained. That amount of SP which regains the exact original
slump taken as the second dose of SP to regained the slump. The amount of
second dose was varied from 0.1 to 1.5 % by weight of cement.
The test method described on the ASTM C143-90 was followed to test the slump.

3. RESULT AND DISCUSSION
3.1. Slump Loss
The rate of slum loss depends on various factors such as initial slump, type anddose of SP, ambient temperature, water binder ratio, type of cement and amountof cement. The figure 3 gives the relation between slump losses with time for NP
based and PC based admixture with different cement content. The figure showsthat mix with NP based SP loss the slump faster than mix with PC based althoughdose of NP is higher than PC. This may be due to that NP based type SP
dispersing mechanism; it is strongly affected by ionic strength of pore solution.
The higher the ionic strength the lower the repulsive force. Negative charges
induced between 20 to 40 mV [7]. Workability loss occurs when adsorbed
polyelectrolyte layer are compressed by the ionic concentration in pore solution
can re-flocculation of cement particles [8]. Molecular structure of PC based SP
has side chains which can provide sufficient distance between cement particles, sothat Van der Waals force cannot act and its negative charge induced less than 10
mV (Ionic strength of pore solution is lower than NP based)[9]. In practice,admixtures based on steric hindrance can provide sufficient workability for longer
period than NP based. Workability loss occurs when side chains are incorporated
by growing hydration layers [9].

Figure 3: Slump Loss of Concrete
3.2. Second Dose of SP to Regain Original Slump
The figure 4 shows that when the SP is re-dosed the slump of concrete is regained.
SP are surface acting agents absorbed on the cement and fine particles giving
surface charge and made then repulsion. Addition of SP may increase zeta

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potential of cement, at the same time viscosity decreased. Increased zeta
potentials help to disperse the cement particles and make the concrete moreworkable and slump is regained. [10]Figure 5 shows the relation between the percentage slump loss and second dose of
SP to regain the original slump. It shows that even for the same percentage slump
loss amount of second dose of SP required is more for mix with NP based SP as
compare with PC based SP. PC based SP; amount of second dose of SP is
between 0.1 and 0.2 percentages by weight of cement for eight percentage slump
losses. This is because of the water reducing efficiency of each SP. Figure 6
shows water reducing efficiency of both NP and PC based SP. PC based SP has
significantly higher water reducing efficiency than NP based especially in lower
SP dose.

Figure 4: Concept of Re-Dose

Figure 5: Relation between Percentage Slump loss and Second DoseSlump
Controlof Fresh
Concretepolycarboxylic
by Re-dosing Polycarboxylic
Based Superplasticizer an
Slump controlof freshconcreteby re-dosing
based superplasticizer
1215dComparison
withNaphthaleneBasedand comparison with naphthalene based

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
VietnamFigure 6: Water reducing efficiency of NP (MXT) and PC (ADVA 208)
From the figure 5 general relation between second dose of SP and percentage
slump loss is given by
y = ae (bx)
Where, ‘a’ and ‘b’: constant, y: percentage of second dose of SP with the totalbinder, x: percentage of slump loss with respect to original slump.
The value of ‘a’ = 0.161, 0.0138, ‘b’=0.017, 0.029 for NP based and PC based SP
respectively for particular water binder ratio and initial dose of SP.

3.3. Effect on Compressive Strength
Figure 7 and 8 shows the compressive strength of concrete with and without redose, concrete with paste content 1.1 and 1.2 and water binder ratio 0.63. It was
found that variation of compressive strength is less than ten percentages.

Figure 7: Compressive Strength in 3, 7, 14 and 28 Days with and without Redosing (Paste content 1.1 water=0.63)

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Figure 8: Compressive Strength in 3, 7, 14 and 28 Day with and without Redosing(Paste content 1.2 and water binder = 0.63)

4. CONCLUSION
From the experimental data it has been concluded that, the second dose of SP
basically depend up on percentage of slump loss and type of SP used for theparticular mix. Second dose of PC based SP is too less even for high percentage
loss so it seems that addition of second dose of SP in the field, NP based SP seems
easier practically than PC based (difficult to re-dose mix and make homogenous atsite). There is no any significant effect on the compressive strength due to theaddition of second dose of SP.

ACKNOWLEDGMENTS
Authors would like to thank all team members of Civil Engineering Laboratory,
SIIT and all members of CONTEC, SIIT for their valuable suggestion and help
during the experiment time. Authors would like special thank to Mr.Wittawat
Pattaranawic for helping to collect some data.

REFERENCES[1]Glanville W H et al 1947, “The grading of aggregate and workability ofconcrete,” Road and research Tech. Paper No. 5[2]ASTM 125-00 “Standard Terminology Relating to Concrete and Concrete
Aggregates”[3]ACI Committee 212, Chemical Admixture for concrete, in ACI Manual of
concrete Practice, Vol. 1 , PP 212R to 212R-22, 1996

Slump
Controlof Fresh
Concretepolycarboxylic
by Re-dosing Polycarboxylic
Based Superplasticizer an
Slump controlof freshconcreteby re-dosing
based superplasticizer
1217dComparison
withNaphthaleneBasedand comparison with naphthalene based

October
2013, 2013,
Hanoi,Hanoi,
Vietnam0ctober
Vietnam[4]Olafur H. Wallevik and Stefan Kubens, 2008 “Effect of Water, Superplasticizer,
Air- entraining agent and Water to Cement Ratio on Rheological Properties ofMortar”, Innovation Center Iceland, IBRI-Rheocenter.
[5]Wanichlamlert C., Tangtermsirikul S. October 2011, “2nd Dose ofSuperplasticizer and Slump Recovery of Concrete Using Naphthalene Based
Superplasticizer” 10th International Symposium on New Technology for
Urban Safety of Mega Cities in Asia.
[6]Erdog S. 2005, “Effect of Retempering with Superplasticizer Admixtures on
Slump Loss and Compressive Strength of Concrete Subjected to Prolonged
Mixing”, Cement and Concrete Research 35 (2005) 907– 912[7]Li, C.Z., et al., 2005 “Effects of Polyethlene Oxide Chains on the Performanceof Polycarboxylate-Type Water Reducers”, Cement and Concrete Research 35,
pp.867-873.
[8]Kong, H.J., et al., 2006 “Effects of a Strong Polyelectrolyte on the
Rheological Properties of Concentrated Cementitious Suspensions”, Cement
and Concrete Research 36, pp.851-857.
[9]Yoshioka, K., et al., 1997 “Role of Steric Hindrance in the Performanceof Water Reducers for Concrete”, Journal of Amercian Ceramic Society
80 (10), p.2667-2672.
[10] Helge Hodne, 2007 “Rheological Performance of Cementitious Materials
Used in Well Cementing”, Doctoral Thesis, University of Stavanger, Norway.

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