New Technologies for
Urban Safety of Mega Cities in Asia

9-10 December 2007
Dhaka, Bangladesh

Edited byMehedi Ahmed Ansari
andKawin Worakanchana

Co-Organized by
Bangladesh Network Office for Urban Safety (BNUS),
BUET, Dhaka, Bangladesh&International Center for Urban Safety Engineering (ICUS)
Institute of Industrial Science
The University of Tokyo, Japan

NEW TECHNOLOGIES FORURBAN SAFETY OF MEGA CITIES IN ASIA
MEHIDI AHMED ANSARY
Chairman Organizing Committee
USMCA2007

ICUS Report No 27, April, 2008
PREFACEIn almost all Mega Cities in Asia, due to the rapid economic growthand development, many high-rise buildings and complex infrastructure
systems have been constructed in recent decades. Of prime concern is thehigh concentration of population, haphazard land development andcommercial activities taking place in these cities. Other critical issues thatare associated with the rapid urbanization include: environmental problems,
supply of water, gas and power, sanitation, transportation, etc. It is therefore
reasonable to postulate that the consequences of even a moderate level ofnatural event in the form of cyclone, earthquake, torrential flood, tornado,
tsunami, etc. may be enormous in these cities. For instance, the recent
Sumatra Earthquake and associated tsunami of December 2004 and October2005 Kashmir Earthquake caused severe damage and a massive loss of lifein the region. Urban safety of mega cities in Asia has therefore naturally
become a prime concern for the architects, engineers, planners andpolicymakers. It also poses a real challenge to them alike due to its multidimensional nature, which covers areas from structural design, maintenanceand rehabilitation to disaster mitigation and risk assessment.
Recent development of various advanced technologies has provided
motivation to focus on devising new methodologies for sustainable
development of Asian mega cities with adequate safety and security. With
this realization and recognition of the importance of using advanced tools inurban safety, the International Centre for Urban Safety Engineering wasestablished at the Institute of Industrial Science, The University of Tokyo,
and has taken the lead in organizing this series of symposia in the Asian
region. After the successful completion of the earlier symposia in Thailand,
Japan, India, Singapore and again in Thailand in 2002, 2003, 2004, 2005
and 2006, respectively, the present sixth symposium is being jointly
organized by BNUS, BUET, Bangladesh and ICUS, IIS, The University ofTokyo, Japan. The symposium is sponsored by the Foundation for the
Promotion of Industrial Science, Japan, Center of Excellence, The
University of Tokyo and CEGIS, Bangladesh. It is also nominally supportedby the Embassy of Japan, Bangladesh.

December 2007, Dhaka, Bangladesh

Focus of this symposium is to help local and regional officials andexperts involved in safety and security practice to enhance their knowledge
by effectively disseminating information on new technologies for urban
safety. It will provide a platform for developing and strengthening a network
among the Asian researchers and practitioners for future collaboration indiverse areas related to urban safety. To accomplish these objectives, thesymposium will have two keynote sessions and ten parallel sessions on
Safety Assessment and Monitoring of Existing Infrastructure, Advanced
Technologies for Assessment of Urban Safety, Maintenance, Retrofitting andRehabilitation of Structures, Design and Assessment of Structures for
Seismic, and Impact Loads, Disaster Management, Tsunamis, Flood andEnvironmental Risk Assessment and Urban Road Safety. These sessions will
present more than seventy technical papers including two keynote and fiveplenary papers.
I would like to take this opportunity to thank the Steering, Technicaland Organizing Committees as well as the Symposium Secretariat and ICUS
staffs for their time and effort in putting this symposium together. Special
thanks are due to the authors of technical papers, participants and all others
who took time out of their schedules to contribute to the success of this
symposium. I would also like to thank the sponsors for their generous
support and contribution.

New Technologies for Urban Safety of Mega Cities in Asia

December 2007, Dhaka, Bangladesh

Table of Contents
Page
Opening Session
SECTION 1
Keynote Lectures
The World Seismic Safety Initiative-What We Do and Do not Do?

1(Keynote Lecture)

Tsuneo Katayama
Forensic Diagnosis of Underwater Slope failure in Jamuna River

11(Keynote Lecture)

Kenji Ishihara, Yoshimichi Tsukamoto
Distress in the Tarmac at Newly Opened Suvarnabhumi Airport

41(Keynote Lecture)

Worsak Kanok-Nukulchai
Safety Problems Related to Deterioration of Concrete Structures

51(Keynote Lecture)

Taketo Uomoto
Proposal of a Sustainable Tsunami Disaster Mitigation System for the Indian Ocean
Region61(Keynote Lecture)

Kimiro Meguro, Masasuke Takashima

Technical Sessions
SECTION 2
Safety Assessment and Monitoring of Existing Infrastructure 1
Digital Chi-Chi City on Google Earth as Post-Earthquake Recovery Digital Archive
Osamu Murao, Atsushi Miyamoto

67

Visual Screening Methods for Earthquake Vunerability Assessment
A. B. Afifa Imtiaz, Mahfuza Shamim, Ashutosh Sutra Dhar, Mehedi Ahmed Ansary,
Mohammad Zobair, Md. Zakaria Ahmad

79

Numerical and Experimental Study of Structures with Soft Stories
Himadree Roy, Iftekhar Anam

91

Seismic Vulnerability Assessment of RC Building of Dhaka City
Mohammad Sajedul Hug, Mohammad Rafat Sadat, Mohammad Salahuddin Rizvi,
Md. Nafiul Haque, Mehedi Ahmed Ansary

103

Assessment of Cyclone Shelters in Cox’s Bazar against Earthquake Hazard
Rajan Saha, Ashutosh Sutradhar, Mehedi Ahmed Ansary

113

Partially Encased Composite Columns: An Innovative Composite Structural System
Mahbuba Begum

127

New Technologies for Urban Safety of Mega Cities in Asia

December 2007, Dhaka, Bangladesh

SECTION 3

Advanced Technologies for Assessment of Urban Safety 1

A Study on Effect of Land-Use Control along Active Faults in Japan
Miho Yoshimura Ohara, Kimiro Meguro

139

Application of Geophysical Imaging in Subsurface Characterization for Urban Safety
from Earthquake – A Case Study from Dhaka Mega City, Bangladesh
Aftab Alam Khan, Muhammad Shahadat Hossain

147

Estimation of Risk Due to Earthquake Hazard in Ap, India an it Based Approach
Md. Ziya Ur Rahman Siddiqui, Ranjeet Joshi, Ramancharla Pradeep Kumar

161

Model Test measuring Earth Pressure Acting on Buried Structure Due to Differential
Settlement
Reiko Kuwano, Toshiyuki Horii, Hidetoshi Kohashi

173

Landslide Hazard Aalysis for Urban Areas Using Raster Data Set
Md. Zahid Hasan Siddiquee, Monsur Ahmed, Rubel Das

183

Seismic Microzonation of Cox’s Bazar Bangladesh
A. B. Afifa Imtiaz, Mehedi Ahmed Ansary, Ashutosh Sutra Dhar

191

SECTION 4

Maintenance, Retrofitting and Rehabilitation of Structures

Influence of Re-curing Condition on Damage and Recovery of Mortar Exposed toFireMichael Henry, Yoshitaka Kato

201

Strategic Maintenance of Port and Harbor Concrete Structures Based on Life-Cycle
Management
Hiroshi Yokota, Mitsuyasu Iwanami, Toru Yamaji, Ema Kato

211

Variation of Corrosion Characterization of Reinforcing Bar in Existing RC Structure
Ema Kato, Mitsuyasu Iwanami, Hirosi Yokota, Takumi Shimomura

221

Evaluation of the Seismic Vulnerability of Bangladeshi RC Building using NonDestructive Testing
Syed Zillur Rahman, Mehedi Ahmed Ansary, MA Noor, Rajan Saha, Hisashi Kanada,
Miho Yoshimura, Kimiro Meguro, Taketo Uomoto

231

Ductility of Concrete Structures with Lateral Confinement and Compression
Reinforcement
Md. Shah Aziz Akand, Iftekhar Anam

243

SECTION 5

Design and Assessment of Structures for Seismic and Impact Loads

Residual Seismic Capacity Estimation of RC Frames with Unreinforced Concrete
Block Infill
Ho Choi, Yoshiaki Nakano

253

The Effect of Infills on the Dynamic Behavior of RC Frames
Samy Muhammad Reza, Raquib Ahsan, Mehedi Ahmed Ansary

265

New Technologies for Urban Safety of Mega Cities in Asia

December 2007, Dhaka, Bangladesh

Analysis of Axial Vibration of Piles in Layered Soil and Application to Batter Pile
Foundations
Raquib Ahsan, Jorgen Johansen, Kazuo Konagai, Hidetaki Tanaka

275

Seismic Assessment of Pile Founded Khilgaon Flyover Mahbuba Begum
Mohammad Moslem Uddin, Mehedi A. Ansary, Tahsin R. Hossain, Munaz A. Noor

287

Proposal of a Methodology to Design PP-band Meshes to Retrofit Low Earthquake
Resistant Unreinforced Masonry Houses
Paola Mayorca, Kimiro Meguro

297

Modeling Nonlinear Stress-Strain Relations of Materials
Md. Raquibul Hossain, Mohammed Saiful Alam Siddiquee, Syed Ishtiaq Ahmed

307

SECTION 6

Disaster Management 1

Enhancement on Disaster Prevention and Mitigation in Kaohsiung City
Tai-Ping Chang

311

Models of a Technical Platform for Emergency Management
Weng Wenguo

321

The State-of-the-Art of Information Technology on Disaster Prevention and
Mitigation in Taiwan Urban Area
Kai-Lin Hsu

333

Experimental Study of Fire Propagation in a Compartment with Different
Approaching Wind Conditions
Hong Huang, Ryozo Ooka, Naian Liu, Linhe Zhang, Zhihua Deng, Shinsuke Kato

343

SECTION 7

Tsunamis, Flood and Environmental Risk Assessment

Protective Measures of Flood Embankment along the Jamura River in Bangladesh
Md. Musur Rahman, Mohammad Asad Hussain, Md. Motaher Hossain,
Maminul Haque Sarker and Mohammad Nazim Uddin

357

Developing an Universal Water Resource Assessment Model for Sustainable Water
SecurityAkiyuki Kawasaki, Srikantha Herath, Kimiro Meguro

367

Application of Remote sensing and GIS techniques in Water induced Disaster
Management: A case Study of Bangladesh
Md. Shahabul Islam, Md. Mafizur Rahman, Kul Prathuchai

375

Climatic Perturbation and Flood Risk in Coastal Cities: A Comparative Study inSouth and South East Asia
Dushmanta Dutta

385

Spontaneous Urbanization of Dhaka City and Water Logging as a Consequence
Umma Tamima, Md. Sohel Reza Amin

397

New Technologies for Urban Safety of Mega Cities in Asia

December 2007, Dhaka, Bangladesh

SECTION 8

Advanced Technologies for Assessment of Urban Safety 2

Study on the Potential of Tree Shape Classification by Using the Simulated LIDAR
Data and a Tree Crown Model
Takahiro Endo, Yoshifumi Yasuoka

409

LIDAR: A Technology of New Era
Mohammad Abdul Quader, MD. Zahid Hasan Siddiquee, Ruble Das

417

Management of Building Energy Consumption and Renewable Energy Supply in the
Ecological Communities Using GIS
Md. Zahid Hassan Siddiquee, Ursula Eicker, Dietrich Schroder

425

Comparative Analysis and Monitoring of Urban Heat Island Intensity in Asian Mega
Cities by MODIS
Wataru Takeuchi, Kawin Worakanchana, Yoshifumi Yasuoka, Vibarad Phonekeo

435

Numerical Simulation of Atmospheric Pollution over Kanto area using the
MM5/CMAQ Model “Simulation of Ozone Concentration between Two Different
Weather Days”
M. V. Khiem, H. Hayami, H. Huang, R. Ooka

441

SECTION 9

Safety Assessment and Monitoring of Existing Infrastructure 2

Automatic and Real-Time Bridge Health Monitoring for Heavy Traffic Routes
Sanae Miyazaki, Yuji Ishikawa, Takahide Okubo, Kimihiko Izumi, Eiichi Sasaki,
Chitoshi Miki

453

3-D Applied Element Method for PP-Band Retrofitted Masonry
Worakanchan Kawin, Paola Mayoca, Ramesh Guragain, Sathiparan Navaratnaraj,
Kimiro Meguro

461

Structural Health Assessment of Infrastructure: The Bangladesh Perspective
Rais Ahmad, M. Kabirul Islam, M. Zakaria Ahmed, Tribikram Kundu

473

Investigation for Promoting Seismic Retrofit of Critical Facilities-A Case Study ofWakayama City
R Amano, Takeyuki Ebi, SShogo Hayashi, Kimiro Meguro, Kouji Uematsu, Kazuhisa Fujita

483

Fragility Analysis of Reinforced Concrete Frame Structures
MA Noor and M Yasin

499

Flood in Bangladesh with Focuses on 2007 Flood
Md. Aynual Kabir

509

SECTION 10

Disaster Management 2

A Study for Improving Total Disaster Reduction Ability of Nursery Schools andKingergartens
Mariko Abe, Kimiro Meguro

New Technologies for Urban Safety of Mega Cities in Asia

521

December 2007, Dhaka, Bangladesh

School Earthquake Safety Program (SESP) in Old Dhaka, Bangladesh
Israt Jahan, Mehedi Ahmed Ansary

529

Vulnerability Risk Areas of Bangladesh due to Multiple Natural Hazards
M.S. Akther, Mehedi Ahmed Anasary541

Proposal of Intensity Scales for Different Natural Hazards in Bangladesh
M.S. Akther, Mehedi Ahmed Anasary

555

Some Emerging Hazards in Metropolitan Cities of Bangladesh
KM Maniruzzaman, MA Rahman

573

Earthquake Preparedness Helps to Combat Urban Disasters
Wahida Bashar Ahmed

579

Earthquake preparedness Combined with Community Efforts
Md. Faiz Shah585

Socio-Economic and Environmental Aspects of Disaster Risk Reduction Management
for Sustainable Development in Bangladesh
Murshed Ahmed

591

SECTION 11

Urban Road Safety

Urban Road Safety: Effective Rescue of Accident Victims Using GIS Technology
Md Mazharul Hoque, Kazi Md Shifun Newaz, S M Sohel Mahmud, Sabreena Anowar
Armana Sabiha Hung

607

Comparative Analysis of On-Street Parking Management Practices in Different
Countries
Shinji Tanaka, Masao Kuwahara

621

Public Transport in Bangkok: A Case of the Passenger Vans
Shinya Hanoka, Supaporn Kaewko Leopairojna

631

Evaluation of Effectiveness of Pedestrian Overpasses in Dhaka Metropolitan
Md. Mizanur Rahman, Muhammad Ashikul Islam, Md. Kamrul Hasan Rizvi

643

Road Traffic Accidents and Injuries: A Serious Safety Concern in Urban Areas of
Bangladesh
Md. Mazharul Hoque, Chowdhury Kawsar Arefin Siddiquii, Tahera Anjuman,
Sabreena Anowar, Shahnewaz Hasanat-E-Rabbi

653

New Technologies for Urban Safety of Mega Cities in Asia

December 2007, Dhaka, Bangladesh

Photograph

USMCA2007 Group Photo

New Technologies for Urban Safety of Mega Cities in Asiai

December 2007, Dhaka, Bangladesh

ii

Welcome board

Registration

ICUS booth at symposium

Opening ceremony

Prof. J. R. Choudhury

Prof. A. M. M. Safiullah

HE Masayuki Inoue

Prof. Mehedi A. Ansary
New Technologies for Urban Safety of Mega Cities in Asia

December 2007, Dhaka, Bangladesh

Mourning ceremony

Prof. Tsuneo Katayama

Prof. Kimiro Meguro

Mr. Tapan Chowdhury

Prof. Kenji Ishihara

Prof. Worsak Kanok-Nukulchai

Signing MOU Ceremony
between ICUS and AIT

New Technologies for Urban Safety of Mega Cities in Asiaiii

December 2007, Dhaka, Bangladesh

Dr. Yoshitaka Kato

Dr. Ryozo Ooka

BanquetBanquetBanquetiv

New Technologies for Urban Safety of Mega Cities in Asia

December 2007, Dhaka, Bangladesh

Prof. Hiroshi Yokota

Dr. Wataru Takeuchi

Dr. Ema Kato

Young-researcher-award awardees

BNUS office in BUET

Delegates from symposium visiting civilengineering department at BUET

Delegates from symposium visiting BUETNew Technologies for Urban Safety of Mega Cities in Asia

Group Photo at BUETv

Opening Session

THE WORLD SEISMIC SAFETY
INITIATIVE – WHAT WE DO
AND DO NOT DOTSUNEO KATAYAMATokyo Denki University, Tokyo, Japankatayama@cck.dendai.ac.jp

ABSTRACTThe World Seismic Safety Initiative (WSSI) was established in 1992
following the decisions made by the International Association for
Earthquake Engineering (IAEE) during the 10th World Conference on
Earthquake Engineering (10WCEE) in Madrid in support of the United
Nations' “International Decade for Natural Disaster Reduction (IDNDR).”IDNDR was a brainchild of earthquake engineering professionals, because
its original concept was presented in 1984 by Dr. Frank Press in his
Keynote Speech during 7WCEE in San Francisco.
Although IAEE endorsed the idea and recommended its prompt
implementation, there had been difficulties for IAEE to take any definite
actions because of its structural weakness. The proposal of the Decade,however, gained the attention of academic institutions and associations
worldwide, and, in December 1987, a United Nations (UN) General
Assembly Resolution declared the 1990's as the UN’s IDNDR (1990-2000)
to promote internationally coordinated efforts to reduce losses caused bynatural disasters, especially in developing countries.
WSSI was incorporated in Singapore in May 1995 as a non-profit
public benefit company, and is operated by its international Board of 15
Directors. Since its foundation, WSSI has been actively working to makeconcrete measures to mitigate losses causes by earthquakes especially in the
Asian developing region. WSSI tries to make visible outcomes, however
small they may be, because disasters respect our actions, not our words.
WSSI holds High Level Meetings to help raise public and government
awareness of earthquake risk in the decision-making sector. We carry out aproject to facilitate the redistribution of seismometers to be replaced in the
U.S. to developing countries. Awards have so far been given to Armenia,
India, China (2 places), and Bangladesh with a total number of about 400
such seismometers.
WSSI is not a funding agency. WSSI tries to trigger local high efforts,build on and encourage local resources, and to help identify and prioritize
local actions. We also attempt to assist in adding credibility to local efforts.

1

December 2007, Dhaka, Bangladesh

1.

PRE-HISTORY

More than 20 years have passed since we heard Frank Press' keynote
address in San Francisco during the eighth World Conference on
Earthquake Engineering (8WCEE) in 1984. He proposed in his speech an
idea of establishing the International Decade for Hazard Reduction in witch
all nations join forces to reduce the consequences of natural disasters. He
emphasized what better way to start the new millennium than a world betterorganized to reduce suffering from natural disasters.
Researchers are often simple-minded. IAEE endorsed the idea andrecommended its prompt implementation without realizing difficulties to be
met once the idea would materialize. During the following four years until
earthquake engineers met again in Japan for the WCEE, no progress or any
efforts to make progresses had been made among earthquake engineers andscientists.
The biggest change for me, however, was that I had been appointed to
be Secretary General of IAEE. The International Decade for Natural
Disaster Reduction (IDNDR) was to be inaugurated in 1990 as an official
UN project. We knew that IDNDR was our brainchild. IAEE again
adopted a resolution, and urged Secretary General to take some actions to
support this very worthy project. All that IAEE did, however, was toestablish a small IDNDR committee. People often ironically say there is no
crisis to which academics will not respond with a committee or a workshop.
The IAEE was established in 1963 to promote international
cooperation among scientists and engineers in the field of earthquake
engineers with its Central Office in Japan. The members of IAEE arenational or regional organizations. There are about 55 members in the
Association. Although IAEE is very visible through the World Conferenceon Earthquake Engineering (WCEE) held every four years, its
administration is not well organized, and until very recently there were nodues for member counties. The WCEE is held by the sole responsibility of
its inviting member country. Most of important businesses are managed
through the General Assembly of Delegates and the Executive Committee
Meeting, both held during WCEE.
Creation of the committee turned out to be only superficial, and it took
three years to organize a small meeting in Tokyo in October 1991. The
meeting was an occasion of harsh self examination. The meeting resolvedthat IAEE should make any structural changes that will facilitate its ability
to promote the earthquake engineering program for the Decade, and that itshould prepare a working paper on the IAEE's role in the Decade so that
discussions would be made during 10WCEE scheduled in Madrid in 1992.
The 10th WCEE was held in Madrid in July 1992. During thisConference, it was everybody understands that, unless a special initiative isestablished with the capacity of gathering people and funds, the possibility
for IAEE to have a significant impact on IDNDR was remote. IAEE2

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

decided to form the World Seismic Safety Initiative (WSSI) as a newundertaking of IAEE in support of IDNDR with the goals to disseminate
state-of-the-art earthquake engineering information throughout the world, toincorporate experience and research findings into recommended practices
and codes in earthquake-prone countries, and to advance engineeringknowledge through problem-focused research. Our understanding is thatdisasters respect our actions, not our words. The first Board of Directors
Meeting of WSSI was held in Tokyo in September, 1993.
WSSI was incorporated in Singapore in May 1995 as a non-profit
public benefit company under the name, "World Seismic Safety Initiative
Ltd." Incorporation was necessary for liability and fund-raising reasons.
The non-profit terms of incorporation are favorable to tax status. As of
October 2007, WSSI is operated by its international Board of 15 Directors.
Seven Directors are from Asia, 4 from North America, 2 from New Zealand,and 2 from Europe. The present Chairman is Haresh C. Shah. The
Directors meet in Singapore at least once a year.

2. BANGKOK WORKSHOPS
In January 1993, the Scientific and Technical Committee (STC) of IDNDR
was held in New Delhi, India. Prof. Shah and Katayama attended thismeeting and proposed WSSI as a new IDNDR project. WSSI was officiallyapproved as an International and Regional IDNDR project.
Immediately following the STC in India, WSSI held a workshop,“Seismic Risk Management for Countries of the Asia Pacific Region” inearly February 1993 in Bangkok as its first initiative. The Asia Pacificregion historically has experienced extensive economic and human losses
from earthquakes (You only have to remember the recent damaging
earthquakes in Iran and Pakistan, and the devastating Tsunamis in the Indian
Ocean.) The region in recent decades, however, has been going throughmajor urbanization and economic development.
It was thought, therefore, most appropriate for WSSI to compile astatus of earthquake mitigation policies and plans in place in the countries of
the Asia Pacific region. We invited about 30 participants from 19 countries
to a golf club in a suburb of Bangkok. Participants from developing
countries were invited. There were participants from such countries as
Bangladesh, Brunei, Malaysia, Myanmar, Nepal, Pakistan, Thailand, andVietnam. Undisturbed by the noise from the city of Bangkok, all of us
freely and sincerely discussed the dilemma we faced. The challenge was tofind the right combinations of actions that would mitigate the earthquake
risk through integrated strategy, consistent with the available resources ofthese countries and aspirations of their citizens.
This first modest but definitive step of WSSI turned out to be a great
success beyond any expectations. We strongly felt that WSSI was not going

The World Seismic Safety Initiative – What We Do and Do Not

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December 2007, Dhaka, Bangladesh

to be another paper organization, and that we could make a dent inmanaging earthquake risk in developing countries.
Participants reported on the state-of-the-art in earthquake engineeringin their countries. They commented on how the available knowledge is used
or not used in developing earthquake disaster mitigation strategies. Theyrequested WSSI to help raise public and government awareness ofearthquake risk in the decision-making sector, in particular. Towards thisobjective, WSSI recognized the importance of holding High Level Meetings
to be attended by government officials, business leaders, people from socialand cultural institutions, as well as the mass media.
The greatest asset from the Bangkok Workshop is the feeling ofpartnership we cultivated among all the participants from developed anddeveloping countries in the field of earthquake disaster mitigation science.
Whenever we face hardship in managing WSSI, we remember the Bangkok
Workshop and the colleagues who have the common goal to mitigate theearthquake calamity.
Two follow-up workshops were held in Bangkok approximately every
5 years to review what effects WSSI had made since the first workshop in
1993. Each of the 3-day workshops cost about 35,000 US$ including air
fares and accommodation for all the participants from developing countries.

3. HIGH LEVEL MEETINGSWSSI has so far held more than ten High Level Meetings (HLM) in suchcities as Kuala Lumpur (Malaysia), Singapore, Kathmandu (Nepal), Dhaka(Bangladesh), Colombo (Sri Lanka), Yangon (Myanmar), Hanoi (Vietnam),Kampala (Uganda), and Ulaanbaatar (Mongolia). HLM has become themost important activity of WSSI. It, however, is a long-ranged educational
project in which short-term outcomes are difficult to expect.
One-day lecture meeting for a wider audience interested in disasterproblems usually accompanies an HLM. In the case of the HLM held in
Kampala (Uganda), in December 1997, the President of Uganda delivered akeynote speech to more than 300 professionals, and promised thegovernment's commitment to provide increased resources.
Preparation of HLM is made by local hosts, and WSSI Directors andresource person(s) attend it with their own funds. Past experiences haveclearly indicated that good partnership and strong personal ties between thelocal hosts and WSSI are always essential for a successful HLM.
I remember the Myanmar HLM in 1996 which turned out to be an
absolute failure. A participant from Myanmar in the first (1993) Bangkok
Workshop requested WSSI to hold an HLM in Yangon while both of us
were in Bangkok. Myanmar was not an easy country to visit in those days.

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We could not get through to a person we wanted to talk on the phone.
Answers to our faxes were hard to come. It was impossible to adequately
prepare the meeting at all. But we were optimistic, because we had
successfully held six HLM’s by then. We thought that things should gowell once we were there.
When we arrived at the country, however, we found nothing had been
prepared for the HLM and there was no person to talk to. We visited, one
by one, a university, the national railway company, and several otherdisaster-related organizations. Nobody knew about WSSI nor showed any
interest in earthquake disaster mitigation in Myanmar. But when we left thecountry, we were still optimistic. Our friend from the Bangkok Workshop
came to see us on the morning of our departure to tell us that the next timeshould be different.
And the “next” time came soon. During our first visit, we found that
there were only few seismologists and earthquake engineers in the country,
and that there was almost no strong-motion seismometer in Myanmar. With
the assistance of a Japanese geotechnical consulting firm, WSSI donatedseveral strong-motion seismometers. Also through the same company,
WSSI invited two scientists to Japan to teach how to handle the instruments.
As the result of these and other continued grass roots efforts, we received in
1999 an official invitation from Myanmar to hold an HLM and a special
lecture meeting there.
Following this invitation, in February 2003, a group of 7 WSSIrelated volunteers from 5 countries traveled to Myanmar to present an
introductory course on earthquake engineering and to encourage Myanmar
to develop a university program for earthquake engineering as well as anearthquake resistant design code. The course was a collaborative effort
between WSSI and the government of Myanmar, and attended by more than
30 engineers and scientists. Before the course started, Minister forTransport welcomed WSSI members to Yangon. He made a speech about
the recent developments in Myanmar, stating how grateful he was for the
WSSI visit.
The timing of the course was appropriate since Myanmar at that time
was considering allowing construction of buildings considerably taller than
10 stories and there was governmental concern about the earthquake
resistance of these structures. They had established the Myanmar
Earthquake Society. Resolutions involving a discussion about the best way
to further develop earthquake engineering in Myanmar were made andvoted on. It was decided that a building design code should be written firstsince building design, and commercial development using buildings, areoften controlled by private industry. If a design code for buildings can be
developed and building regulations can be enforced, then it should be
relatively easy to develop enforceable codes for other structures over whichgovernment control is likely to be stronger.

The World Seismic Safety Initiative – What We Do and Do Not

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December 2007, Dhaka, Bangladesh

A workshop with an emphasis on geophysics and faults in Myanmar
was held in Yangon in early 2007. It was found that a building code wasbeing written. A longer course on earthquake engineering was being
planned to be given by one of the WSSI Directors, but it had to be
postponed because of the recent political turmoil in the country. The
experiences with Myanmar have taught us many things, especially theimportance of the continued grass roots efforts in the international
cooperation.

4.

THE POLICY OF WSSI REGARDING FUTURE HLM

When we held the 12th WSSI Board of Director’s Meeting in Singapore in
December 1999, IDNDR was almost coming to an end in year 2000. We,
however, decided to continue the activities within WSSI beyond year 2000,
and adopted an official policy of HLM based on the past experiences. It,
however, was thought necessary for WSSI to define more objectively theroles of the HLM for future. This was especially important because ourresources are extremely limited.
The objectives to be achieved by HLM’s were summarized as follows:◍ To trigger local high level efforts,◍ To build on and encourage local resources,◍ To sensitize people, professionals, administrators andpoliticians,◍ To help identify and prioritize local actions,◍ To assist in developing local sustainability through local efforts,◍ To assist in adding credibility to local efforts,◍ To assist in local efforts in fund raising activities, and◍ To assist in national networking.
Priority should be given to situations dominated by a combination ofhigh seismic risk and low preparedness. More emphasis should be placedon the latter, and attention should also be given to countries withmedium/low seismic risk but low preparedness. In order that precious time,energy and money will not be wasted, it may be necessary to seek dialogues
between local people and WSSI before an HLM is planned.
Given the nature of a typical HLM, it should not be repeated in thesame country. It should be understood that it usually takes time to achieve
the goals set by WSSI, and it will not be appropriate to expect instantimprovement after an HLM. It may be necessary for us to maintain adialogue in order to encourage further local development. WSSI may help
developing countries establish courses in earthquake engineering, disastermanagement, etc. to further increase the local awareness in earthquake
disaster mitigation.

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5.

SAFER CITIES PROJECTSAnother successful and visible activity of WSSI is the Safer Cities Project.
This is a joint initiative of WSSI and the COSMOS (Consortium ofOrganizations for Strong-Motion Observation Systems) of the U.S. The
Safer Cities Project stands for Strong-motion Accelerographs For
Earthquake Loss Reduction in Cities. The Project intends to benefit
societies by redistributing unused strong-motion instrumentation to nonprofit organizations for educational and nonprofit purposes in urbanizedareas with few such instruments to record the next damaging earthquake.
Strong-motion seismometers in many of the COSMOS agency
programs are being replaced with recent versions of instrumentation moresuited to individual agency’s need. The instrumentation being replaced isoften in good working order, but no longer meets the requirements of thehost agency. Towards extending their useful life, this project will facilitate
their redistribution to developing countries. Awards have so far been given
to Armenia, India, China (two areas), and Bangladesh with a total number ofnearly 400 such seismometers.
The project provides instruments to acquire quantitative strongmotion measurements in buildings and on the ground in order to adequately
rebuild damaged cites following major earthquake disasters and to initiate
strong-motion measurement programs in urbanized areas in order that citeswith high seismic risk might acquire critical recordings needed to reduce
earthquake losses. It is hoped that such a project will stimulate awarenessand action to mitigate earthquake hazards in densely urbanized regions
throughout the world,
Transfer cost should be borne by the awarded organization, andinstrumentation transferred under the signed agreement among WSSI,COSMOS, and the awarded organization shall be used for educational andnon-profit purposes with no options for resale. Installation of instrument
and a written report describing installations with maps of locations shall be
provided within one year of receipt of instruments, and COSMOS is
responsible for digitization of recorded data.

6. INTERDISCIPLINARY OBSERVATON OF THE 2001 BHUJ,GUJARAT, EARTHQUAKEWhen we heard that the Bhuj earthquake had hit the northwest region of theState of Gujarat, India, on January 26, 2001, we all knew that, like many
earthquakes in recent times, numerous academic, professional, andhumanitarian organizations in developed countries would send teams ofexperts to study to publish reports which would focus individually on
scientific, technical, economic and social issues. (This did take place in thecase of the Indian Ocean Tsunamis.)

The World Seismic Safety Initiative – What We Do and Do Not

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December 2007, Dhaka, Bangladesh

WSSI came up with an idea of assembling a unique reconnaissanceteam from developed and developing countries around the world withdifferent interests and different professional backgrounds. A team of 21
members from 13 countries was sent to the site to conduct an eight-day trip
visiting 11 cities/towns/villages in the hard-hit region.
This was the first experiment to look at the earthquake consequences
as a learning process for many individuals from developing countries.
Without such an experiment, many of the team members would not havebeen able to have the opportunity to be on the damaged site to see thetechnical, economic, scientific, social, and political forces that contributed
to the death and destruction.
This has been a fascinating experiment and it has brought about aresounding success in terms of how we can raise awareness about
earthquakes and their aftermath. The well-planned reconnaissance cost
WSSI only 30,000 US$ altogether, but it required huge efforts of voluntary
work by some of the WSSI Directors and WSSI-related persons to realize it.
The reconnaissance culminated in a unique report beginning with thefollowing sentences:
It is the dawn of the 51st Republic Day of India, January 26,
2001. Some 400 students with their teachers are marching toward
the town hall of Anjar to participate in the flag hoisting ceremony inobservance of the India Public Day. There is slight chill in the air
on a clear and sunny morning, quite usual during the winter days.
The students, future leaders of republic India, are marching throughvery narrow streets – perhaps less than 10-ft wide – of downtown
Anjar, singing popular patriotic songs. The narrow streets are
surrounded by 2-story stone/masonry buildings. Suddenly, the earth
beneath them snaps, first making a loud noise as if a bomb went off,followed by violent ground shaking that lasts for over a minute.
A cloud of dust arises making it difficult to see what has happened.
When dust clears, the surrounding buildings are no more standing.
The violent shaking of the earth has leveled them burying under its
rubble the marching students and teachers, and some inhabitants ofthe buildings that have collapsed. Joyful singing turns into painfulscreams for help. Very few students and teachers escape injury or
death; most of them perish, leaving their parents and loved ones
behind. It is a sight that Anjar would not forget a very, very longtime to come.
I have never read such moving sentences in any reconnaissancereports written by scientists from developed countries. The report of theteam was well received worldwide. We believe that the make-up of theteam, the purpose of the reconnaissance, and the unique and refreshing wayof learning from this earthquake should become the standard under which
future such efforts will be formulated. However, this has not realized in any

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ICUS Report 27of the recent damaging earthquakes, and hundreds of similar reports arebeing published by groups of so-called experts from developed countries.

7.

IMPORTANCE OF SMALL BUT WELL-FOCUSED PROJECTS

There are many local and international aid bureaucracies promoting thedisaster risk reduction in developing countries. In many cases, those who
benefit are the people involved in the preparation and implementation of aid
projects. People in decision-making positions do not understand theimportance of problems associated with natural disasters. They do not work
closely with non-governmental organizations, but only with the national
governments.
Disaster management projects in developing countries are often based
only on imported technology and methods developed in industrializedcountries. If there is not a proper adaptation of this technology to meet the
local conditions and needs, the implementation of such projects results inmisallocation of investments. In developing countries, regional data is notavailable, which is essential to make the imported methods effective. Whatdeveloping countries need is not new technology but old well-tested
technology that brings important benefits at low costs.
Large, expensive projects with very broad and general objectives only
multiply an already growing bureaucracy and often result in a waste of time,money, and energy, rather than providing real solutions. It is better toestablish small, realistic, well-focused projects that bring people fromdeveloped and developing countries to work together. Such small projects
have better benefit-to-cost ratios than the expensive programs.
We are very glad that WSSI’s efforts are producing some visible fruits
in many places of the world. Countries such as Malaysia, Myanmar, Nepal,
Pakistan, Singapore, Thailand, and Uganda have organized their national
associations for earthquake engineering. They now are IAEE Member
countries. A university in Sri Lanka has established a course in earthquake
engineering to which WSSI donated a dynamic structural analysis
computer-software. In Nepal, awareness for earthquake preparedness has
been visibly raised, and a school building project has started with thecorporation of a US-based non-profit organization. It was a pleasantsurprise that Nepalese carpenters and bricklayers went to India to teach how
to build earthquake resistant houses after the Bhuj earthquake. WSSI, withthe help of a Japanese consulting firm, established a modest-sized networkof strong-motion seismometers in Myanmar.
I personally believe that HLM’s are the most important activity of
WSSI. However, too much emphasis has so far been placed on Asian
countries. Better geographical distribution should be sought in the future.
Candidates may be those from island countries in the Pacific and the
Caribbean Sea, and CIS (Commonwealth Independent States), those in the

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9December 2007, Dhaka, Bangladesh

Central Asia in particular. It is also important to critically review what has
taken place after an HLM by holding a follow-up meeting.
As more people have come to know the name and the activities of
WSSI, we need to have more systematized management. To continue
HLM's on a stable basis, it is vital to decentralize the workload which has
been so far concentrated to a few limited Directors. It may be necessary for
WSSI to prepare a manual showing the process of preparing an HLM. At
the same time, we should not ask too much to Directors because it may
become a burden. After all, Directors work on their voluntary basis.
We know the problem is difficult. Every solution breeds new
problems. We have always thought in the past that, when in doubt, jump!
But, action should not be confused with haste. Energy and patience shouldbe two indispensable elements in the future activities of WSSI.

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FORENSIC DIAGNOSIS OF UNDERWATERSLOPE FAILURE IN JAMUNA RIVER
KENJI ISHIHARA
Professor, Research and Development Initiative
Chuo University, Japan
ke-ishi@po.iijnet.or.jp
YOSHIMICHI TSUKAMOTO
Associate Professor, Department of Civil Engineering
Tokyo University of Science, Japanytsoil@rs.noda.tus.ac.jp
ABSTRACT
When excavation was under progress by dredging through the sandbar deposit in Jamuna River in Bangladesh, a number of slips occurredunderwater. Features of the slips s are first described herein together withthe results of in-situ investigations on the ground conditions. In the fluvial
deposit in the Jamuna riverbed the sand is known to contain a few percentof mica mineral composed of plate-shaped grains. The inclusion of mica
has been known to make the sand behave more strain-softening leading toincreased vulnerability to flow type deformation. This was conceived tohave been the cause of the underwater slides. To confirm this aspect, thesand was recovered from the river site and triaxial tests were performed in
the laboratory extensively. The outcome of the test was compiled andarranged in a manner where the residual strength could be evaluated in a
general framework of interpretation on sand behaviour. The results of thetests showed that the mica-containing sand from Jamuna River site
exhibited contractive or strain-softening behaviour over a wide range ofvoid ratio. The residual strength at the steady-state deformation obtained in
the present test scheme was used to provide an explanation for the
instability of the slopes in the light of what actually happened during theunderwater excavation in Jamuna River.
When excavation was under progress by dredging through the sandbar deposit in Jamuna River in Bangladesh, a number of slips occurredunderwater. Features of the slips s are first described herein together withthe results of in-situ investigations on the ground conditions. In the fluvial
deposit in the Jamuna riverbed the sand is known to contain a few percentof mica mineral composed of plate-shaped grains. The inclusion of mica
has been known to make the sand behave more strain-softening leading toincreased vulnerability to flow type deformation. This was conceived tohave been the cause of the underwater slides. To confirm this aspect, thesand was recovered from the river site and triaxial tests were performed in
the laboratory extensively. The outcome of the test was compiled andarranged in a manner where the residual strength could be evaluated in a
general framework of interpretation on sand behaviour. The results of thetests showed that the mica-containing sand from Jamuna River site

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December 2007, Dhaka, Bangladesh

exhibited contractive or strain-softening behaviour over a wide range ofvoid ratio. The residual strength at the steady-state deformation obtained in
the present test scheme was used to provide an explanation for the
instability of the slopes in the light of what actually happened during theunderwater excavation in Jamuna River.

1. INTRODUCTION
The vast expanse of the flood plain in Jamuna River in Bangladesh has
experienced volatile shifts of river course during the flood period. In a large
project to construct a long bridge, it was considered necessary to protect theabutment of the bridge from scouring and erosion in which the level of theriverbed is purported to change by more than 10m overnight. In order toprovide a countermeasure, excavation of underwater channels were
executed by dredging from ships through the sand bar deposit. The aim wasto reinforce the underwater slope with stones and geotextiles on the side ofabutment. During the excavation, a number of slides took place underwater
thereby inhibiting the operation of construction. In-situ investigations werecarried out extensively by Dutch company and consultants and original
design modified.
To clarify the cause of the slides, various kinds of investigations werecarried out both in the field and in the laboratory. Although the causes werevariously conceived, one of the points unanimously recognized was the factthat the fluvial sand deposit in Jamuna River contains a few percent of mica
mineral exhibiting peculiar behaviour of deformation. In recognition of this,extensive studies were performed in the laboratory by Hight et al. (1999)
and various factors such as anisotropic mode of deposition were addressedas possible causes leading to highly collapsible nature of the micacontaining sand. At the Tokyo University of Science, the scheme oflaboratory studies had been underway regarding the steady-state
deformation characteristics of sandy soils. Some of the results of tests werereported by Ishihara et al. (2003).
With an aim to examine behaviour of Jamuna River sand in terms of
the framework established as above, a large amount of Jamuna River sandwas shipped to Japan and multiple series of triaxial tests were performed toclarify the deformation characteristics of the sand. The results of theundrained triaxial compression and extension tests will be introduced in thispaper within the framework of data arrangements and interpretation
established thus far.
As a result of the studies, it was pointed out that the use of the major
principal stress would be most appropriate to take into account effects ofconfinement on the residual strength of sand, and if based on this, there isno need to consider the effect of K C -conditions at the initial stage ofanisotropic consolidation. The outcome of these laboratory tests wasincorporated into a simple analysis to examine the instability of the slopes
observed in Jamuna River. The analysis targeted for the post-failure

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conditions was performed based on the residual strength. The consequenceof these studies will be described in the following pages.

2.

PROJECTIn the middle reaches of the Jamuna
River in Bangladesh, a 4km-longbridge called Bangabandhu Bridgeconnecting the towns of Sirajganj
and Bhuapur was planned andconstructed in 1995-1999.
Its
location is shown in Figure 1.

As shown in the more detailed
map in Figure 2, the width of theriver channel was about 11km. This
area is the vast expanse of flood
plain and had suffered severe
destruction over the years due tointense flooding over the river
channel and its surroundings.
Devastation
wasparticularly
conspicuous at the time of theflooding in 1987 and 1988. In someareas, river channels are purported
Figure 1: General location map
to have shifted their courses
overnight through several hundred meters. The tendency of the drift isreported to have been westwards whereby involving a huge amount of sandy
soils removed by scouring in the riverbed in the west side of the Jamuna
river.

Figure 2: Locations of the Guide Bunds in Jamuna bridge site

Forensic Diagnosis Of Underwater Slope Failure In Jamuna River

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December 2007, Dhaka, Bangladesh

In the design of the abutment of the Bangabandhu Bridge, it wasconsidered mandatory to implement some countermeasures against thedeleterious effects due to such scouring and to duly control the river channel.
With this aim, construction of guide bunds was planned on both sides of theriver as shown in Figure 2. Of particular importance was the construction of
the West Guide Band, as it was intended to protect the bridge abutment
behind the river from scouring or erosion of the riverbed. The construction
consisted of excavating the riverbed by dredging the sand inland by ships
and placing erosion-protecting armours such as geotextiles and stones overthe underwater slopes on the west side. The location and horseshoe-shaped
plan view of the Guide Bunds are displayed in Figure 3. The trench varying
from 27 to 30m in depth was dug below water by means of cutter-suction
dredgers from ships at the site of each guide bund.

Figure 3: Locations of Slides in the West Guide Bund

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3.

UNDERWATER SLIPS ON EXCAVATED SLOPESThe West Guide Bund was constructed at the site of a recently formed sandisland as seen in Figure 2. The materials forming the dredged slopes werecomposed of young, rapidly deposited sediments. The detailed plan view ofthe excavation is shown in Figure 3 and a typical section (E-W section)across the dredged channel is displayed in Figure 4. The slope on the westside was to be protected by the geotextiles-stone armour against thescouring, because the bridge abutment was to be installed due west of theWest Guide Bund. Thus the underwater slope designated as “permanent
slope” was designed so as to have a gentle slope of 1:5.0 in the middle
portion. On the contrary, the slope on the east side of the dredged channel
was to be left unprotected. Even though slides occur and the sand bar
disappears in future due to scouring or erosion, it did not matter. Thus, theeastern slope was designed to form a steeper slope with an angle of 1:3.0
and designated as “temporary slope” in Figure 4.

Figure 4: East-west section through West Guide Bund Channel(from Hight et al. 1999)
The dredging work began northwards in October 1995 from thesouthern rim of the sand bar. As the dredging proceeded, slope failuresoccurred on the permanent slope on November 19th in 1995 in the crosssection 1270 and another on November 22nd in the cross section 1410.
They are respectively called W1 and W 2 slide and shown in Figure 3. On
December 3, 1995, the largest-in-scale slide denoted by W3 took place on
the permanent slope at a location of Chainage 1550. This slide covered anarea of about 150m wide and 150m long over the permanent slope.
Afterwards many failures were found to have occurred on the temporary
slope during the period of rising water level in 1996. Eleven of them werelarger in scale than W3, and these are indicated by the symbol WT 6, 7, 9,
9E, 13, 15, 16, 17, 18, 22, 24 in Figure 3. Many of these slides delayed theprogress of construction works, but of most serious concern were thefailures on the permanent slope, because they had to be repaired to constructerosion-free slope. In recognition of the instability with an angle of 1:3.5,
the design cross section on the permanent slope was changed so as to have aslope of 1:6.0 near the bottom and for the temporary slope, the angle waschanged from 1:3.0 to 1:5.0 as illustrated in Figure 4. Then, the dredging
work to full depth was resumed to finish excavation of the trench. As the

Forensic Diagnosis Of Underwater Slope Failure In Jamuna River

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December 2007, Dhaka, Bangladesh

dredging went on, a number of slope failures began to occur again but only
on the temporary slope. The failures occurred mostly during the period ofMarch to June in 1996. Exact locations of all of these slope failures
including those prior to and after the design change as well are indicatedtogether in Figure 3.

4.

CAUSES OF SLOPE FAILURES

There are two aspects to be distinguished in clarifying mechanisms of slope
failures in sand deposits. These are generic cause and consequence offailure.
4.1

Causative Incidents

It was difficult to precisely identify generic causes of the slides which
occurred apace in underwater environments. It was envisioned that the overcutting, overstepping or rapid cutting associated with the dredging operation
had been responsible for triggering the slips. There were slow falls in thewater level of the river after storms of the order of 0.1m per day over a
period of five days. This might has been other causes leading to the slips.
The factors such as wave actions and thunderstorms were also suspected tohave triggered the slips. No matter what causes might have been, it iscertain that the sand deposits had been in a precarious state narrowly
keeping the stability when the excavation was made.
4.2

Consequences of Failure

After the initial failure is triggered involving a small or medium
deformation, the soil may or may not develop large displacement later on.
One kind of sand deposits might induce only a limited deformation which istolerable but in another type, a fairly large amount of displacement willcontinue further on. In the latter case, the level of devastation incurred will
be intolerably large. Thus, identification of the damage level in terms ofcontinuation or discontinuation of deformation after the triggering of failure
will pose an important aspect in recognition of the problem particularly insaturated sand deposits under water.
The identification of the consequence of failure as above can be madegenerally by examining the state of an existing deposit as to whether it will
exhibit contractive or dilative behaviour after it has undergone triggering.
In the case of the sand deposit in the Jamuna riverbed, the deposit seems tohave had characteristics showing the contractive or strain-softening type of
behaviour in which the residual strength at a largely deformed state is
reduced significantly leading to an intolerable level of deformation after theslips were triggered. In the above context, soil characteristics were
investigated in details in the field as well as in the laboratory as described
below.

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5.

INVESTIGATION OF SOIL CONDITIONS

Following the occurrence of the slides as well as at the time the design was
made, multiple series of tests were conducted both in the field and in thelaboratory to illucidate nature and properties of soils which are deemed to
be a cause of the slides.

Figure 5: Location of soil investigations at the site of Jamuna
Multipurpose bridge construction
5.1

In-situ tests

Deep borings were performed at three locations, viz., B1 on the westbank and B2 and B3 on the right bank, as shown in Figure 5. The standard
penetration test (SPT) was also conducted at these boring sites. At the site
B3, the measured N-value was, for example, 15 at a depth of 9.25m.
Considering the use of a free falling hammer in the SPT practice at the
Jamuna sites, the energy level is deemed as about 80% of the theoreticalenergy in hammer dropping. This energy level actually consumed forpenetration is considered about the same as the level normally achieved in
the Japanese practice. The SPT N-value at a shallow depth of 6.25m wasfound to be 7 at B3, 10 at B2 and 19 at the site B1. These values are
relatively small indicating the presence of loose sand layer which might beresponsible for triggering the slope failure.
Dutch one-penetration tests (CPT) were also performed at 15 locations
as indicated by C1 to C13 shown in Figure 5. The results of CPT showed
qc-value of 4-5 MPa at depths from 6-8m at the location CDI which is close
to the site B3. This value indicated as well the presence of loose sand layer
at this depth. By comparing the SPT N-value and the CPT qc-value obtained
each in their vicinity, an empirical correlation was established by Delft
Geotechnics as follows,

Forensic Diagnosis Of Underwater Slope Failure In Jamuna River17

December 2007, Dhaka, Bangladesh

qC = 0.31 ⋅ N 60

(1)where N60 indicates the SPT N-value corresponding to 60% of thetheoretical energy. In view of the 80% of the energy achieved in the Jamuna
River investigation, the above relation would be rendered toqC = 0.37 ⋅ N(2)Figure 6: A typical profile of relative density at a site in Jamuna River(Hight et al. 1999)
where N indicate SPT N-value obtained by the free fall hammer which isconsidered to exert 80% of the theoretical energy in the SPT operation. The
relative density at the site was estimated based on the data of SPT and CPT.
One of the typical data by Hight et al. (1999) is shown in Figure 6 where it
may be seen that the relative density takes values around Dr = 50% but the
majority of data indicate values less than 65%.

Figure 7: Effect of 1% mica on the undrained behaviour of sand insimple shear (Hight et al. 1999)

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5.2

Laboratory tests

Sand samples were obtained in-situ by means of the tube samplingtechnique. However, the degree of disturbance appears to be somewhathigh in loose deposits of sand and therefore the outcome of the laboratory
triaxial tests on such samples is considered not truly representative of theconditions of sand deposits prevailing in the field.
Apart from the laboratory tests on intact sand samples, it was
discovered that the sand in the Jamuna River contains a few percent of mica
and its presence was suspected to have created conditions of the deposits
which were highly vulnerable to triggering failure and consequent flowageof the sand. Thus, attention has been drawn to the peculiar behaviour of
mica-containing sand by several investigators. One of the results of simple
shear tests reported by Hight et al. (1999) is reproduced in Figure 7 in which
the behaviour of clean silica sand is compared with that of the same sandbut containing 1% mica.
It can be seen that the loose sand with a void ratio of e=0.70 exhibits
ductile behaviour with a tendency to dilate at largely strained states,
bringing up the effective stress path along the failure line. In stark contrast,
the sand with e=0.74 containing 1% mica is shown to be brittle and have apotential to collapse at medium strains resulting in a small residual strength
at a largely strained state. Hight et al (1999) argued that, because of the
aspect ratio of the mica plate as high as approximately 50:1 compared to therotund sand particles, the presence of even 1% mica by weights isapproximately equivalent to that of 25% of mica by number of grains.
In an effort to investigate more thoroughly the behaviour of micacontaining sand, multiple series of triaxial tests has been conducted at theTokyo University of Science on reconstituted samples of the sand recoveredfrom the Bangabandhu Bridge site in Bangladesh. Details of the tests
procedures and the manner in which data are arranged are descried more indetails in the paper by Tsukamoto et al. (2007). The conduct of the tests on
the Bangladesh and its outcome will be descried somewhat in details in thefollowing pages.

Figure 8: Grain size distribution of the Jamuna River sand tested

Forensic Diagnosis Of Underwater Slope Failure In Jamuna River

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December 2007, Dhaka, Bangladesh

6.

CONDUCT OF TRIAXIAL TESTS ON BANGLADESH SAND

6.1

Material properties

The sand with a few percent mica recovered from the bridge site has atypical grain size distribution curve shown in Figure 8. It is a sand with
D50 = 0.2 mm and contains 10% non-plastic fines. Its specific gravity is
GS = 2.745 and the maximum and minimum void ratio as measured by theStandard of the Japanese Geotechnical Society was emax = 1.202 andemin = 0.602 , respectively.
6.2

Test procedures

In the triaxial tests, the samples 6cm is diameter and 12cm is length
were prepared by the method called wet tamping in which moist sand wasplaced in the mould with varying energy of compaction. By this method, it
was possible to prepare reconstituted samples with widely varying range invoid ratio. After preparing the samples, de-aired water was circulated toachieve a state of full saturation with a B-value greater than 0.95. Then, thesamples were consolidated anisotropically under different K C -conditions.
The axial load was then increased under undrained condition when the modeof the test was triaxial compression. The triaxial extension tests were also
performed by increasing the cell pressure under undrained conditions.
6.3

Results of tests

The results of the undrained compression test on samples with void
ratios ranging between 0.804 and 0.871 are displayed in Figure 9 where thedeviator stress q = σ 1 − σ 3 is plotted versus the effective mean confining
stress defined as p ' = (σ1 + 2σ 3 ' ) / 3 . The saturated samples were consolidatedwith a vertical stress of σ '1C = 98kPa and lateral stress of σ '3C = 49 kPa
producing an initial state of K C =0.5. It may be seen in Figure 9 that thedilatants behaviour is exhibited when the sample is prepared with a void
ratio less than about 0.83, but otherwise the sample is contractive. It is to be
noticed that the sample with e=0.871 has reached a steady-state with adeviator stress of q = 15kPa which is smaller than the initially applied
deviator stress of q = 49 kPa . It is seen in Figure 9 (b) that large deformation
began to occur at an early stage of load application and continues further on
until an axial strain of 20% developed. The smallness of the deviator stressat the steady state as compared to the deviator stress at the outset would be
regarded as a criterion to indicate an unstable condition where flow-type
deformation could be triggered if the peak shear stress is passed over byapplication of a slight agitation at the beginning. Another series of tests
with the same initial lateral stress of σ '3C = 49 kPa but with an increased K C value of 0.7 is demonstrated in Figure 10 for samples with various void
ratios where the general tendency is seen to be the same as those shown in
Figure 9. It may be seen in Figure 10 that the sample consolidated with a20

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deviator stress qC = σ '1C −σ '3C = 20kPa with a void ratio of 0.827 has reached asteady-state with the deviator stress q = 95kPa which is much greater than
the initially applied deviator stress of 20kPa. In such a condition, the flow
type deformation will not be induced because of the gain in shear strength ascompared to the initially applied shear stress. The last series of the tests
with K C = 1.0 are demonstrated in Figure 11 where it is apparently noted thatthe specimen with e=0.767 exhibited highly dilative behaviour. The
characteristic feature of deformation as deduced from the above test results
may be summed up as follows.

Figure 9: Results of undrained triaxial compression tests

Figure 10: Results of undrained triaxial compression tests

Figure 11: Results of undrained triaxial compression tests

Forensic Diagnosis Of Underwater Slope Failure In Jamuna River

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December 2007, Dhaka, Bangladesh

1. It is apparent that the deformation characteristics become moredilative with decreasing void ratio and vice versa. The void ratio forthe threshold can be read off as approximately e=0.83 from the Figs.
9 to 11.
2. Although not clearly displayed in the test results shown in Figs. 9
and 10, a number of tests on Bangladesh sand with greater confining
stresses or tests on other sands have coherently shown that the
deformation characteristics becomes more contractive with increased
K C -value at the stage of anisotropic consolidation.
This isconsistent with the main conclusion derived by Chern (1995), Vard
and Chern (1985), Kato et al. (1999) and Tsukamoto et al. (2007).
3. Similar undrained triaxial tests have been performed on several othersands in Japan which do not contain mica. The outcome of the tests
on such non-mica sand showed that the sand behaviour becomes
more starkly dilative or strain hardening with decrease in void ratio.
In contrast, the mica-containing sand from Bangladesh tends tobecome contractive or to remain at an intermediate state between
contractive and dilative whereby developing large deformation atconstant shear stress qS and effective confining stress p 'S . Thisimplies that the mica-containing sand would easily be put at a
steady-state over a wide range of void ratio. This is consistent withresults of the tests reported by Hight et al. (1999).

7.

FLOW CHARACTERISTICS OF JAMUNA RIVER SAND

From a number of other tests including those shown in Figure 9 through 11,
the void ratio, e, deviator stress qS and effective mean confining stress p'S
at the steady state were read off and plotted in Figure 12 in terms of e versus
p'S . In this plot, those data from the tests with K C =1.0 are displayed withwhite circles and those from anisotropically consolidated samples with K C values less than 1.0 are shown with black circles. It can be seen in
Figure 12 that the steady state line is established uniquely irrespective of the
K C -conditions.

Figure 12: Steady-state line for Jamuna river sand as a plot of void
ratio and effective mean principal stress

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In the whole program of the tests executed at the Tokyo University of
Science, it was shown that the most appropriate parameter indicative of theeffects of confinement at the steady state is not necessarily the mean
principal stress p 'S = (σ '1S +2σ '3S ) / 3, but instead the major principal stressσ '1S alone. In accordance with this concept, the plot is made of the samedata set alternatively in Figure 13 in terms of the void ratio versus theeffective major principal stress σ '1S at the steady state. It can be seen thatthe steady-state line is established equally well again irrespective of K C conditions.

Figure 13: Steady-state line for Jamuna river sand as a plot of void ratio
and effective major principal stress
It is to be recalled that the steady-state lines established in Figure 12
and 13 all do pertain, not to the initial un-deformed state of the sand, but tothe state where the sample is largely deformed to a strain level greater thanabout 5%. One might argue that the specification of a state of soil at thetime it is already deformed may not be appropriate. Thus, it is claimed to bea parameter at the initial state prior to load application that is moreconvenient and hence desirable in view of its practical application when soil
behaviour is to be estimated for subsequent application of shear stress.
Looking back over the development of soil mechanics, one can realize that,in the majority of problems, such as consolidation and undrained shear
strength, it was the initial state of the confining stress that was taken up as aparameter to specify the soil behaviour in the subsequent loading. In thecontext as above, the initial state of void ratio and the major principal stressσ '1C before the application of shear stress were picked up from the whole
file of test data on Jamuna River sand and they are plotted in the diagram of
Figure 14. In this diagram, a line is drawn which differentiates the sample
behaviour between contractive and dilative. Such line was called the Initial
Dividing Line (Ishihara, 1996). It may be seen in Figure, 14 that the Initial
Dividing Line (IDL) can be obtained consistently irrespective of the K C state of samples at the time of anisotropic consolidation. It is to be noticed
here that the steady-state line, quasi-steady state line and initial dividing line

Forensic Diagnosis Of Underwater Slope Failure In Jamuna River

23

December 2007, Dhaka, Bangladesh

are almost coincident particularly in the range of small confining stress lessthan about σ '1C = 100 kPa.
The angle of internal friction at the steady state derived from the samedata file is shown in Figure 15. Although the values are slightly different
between TC-tests and TE-tests, the average value would be taken as
φS = 30°.

Figure 14: Initial dividing line for Jamuna river sand as a plot of void
ratio and initial major principal stress

Figure 15: Angle of internal friction for the steady state
8.

RESIDUAL STRENGTH OF JAMUNA RIVER SAND

It has been customary to define the residual strength, Sus , by referring to theminimum shear stress at the quasi-steady state (QSS) which is mobilized at
the state of phase transformation for sands exhibiting contractive behaviour.
In the mica-containing Bangladesh sand, the test data in Figure 9 to 11 showthat the quasi-steady state (QSS) is almost coincident with the steady state(SS). Thus, these two states could be regarded practically identical for the
mica-containing Jamuna River sand being considered. By denoting thedeviator stress at this state by qS = σ '1S −σ '3 S , residual strength is expressed as(Ishihara, 1996, p.268)

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qS
M
cosφ S =cos φS ⋅ p 'S
22
6 sin φSM =3 − sin φS
Sus =

(3)

where p'S is the mean effective confining stress at the QSS or SS as definedby p 'S = (σ '1S +2σ '3S ) / 3 , M is a parameter related with the angle of phasetransformation in the p '− q plot, and φS is the angle of internal friction at
QSS or SS. When normalizing the residual strength Sus to the initial mean
principal stress, it is written as

Where

Sus M
1
=
cosφS ⋅
p 'C
2rC
p ' C σ '1C +2σ ' 3C
rC ==p ' S σ '1S +2σ ' 3S

(4)

If the residual strength is normalized to the initial major principal
stress σ '1C , it is written as
S us
M 3 − sin φ S
1=⋅⋅ cosφ S ⋅σ '1C
2 3(1 + sin φ S )r 'C
σ'r 'C = 1C
σ '1S

(5)

From the majority of data on undrained triaxial compression tests“TC-test”, the residual stress at largely deformed state of the Jamuna Riversand was read off and normalized to p'C and σ '1C . Similar undrained
triaxial tests were also performed in the extension mode of deformation.
This test is referred to as “TE-test”. The residual strength from the TE-test
was also normalized to p'C and σ '1C . The outcome of such datacompilation is demonstrated in Figure 16, in terms of the plot of thenormalized residual strength versus the K C -values employed in each of thetests. Among the cluster of data points, the initial state of the samples
exhibiting the contractive behaviour in subsequent undrained loading is
indicated by the black symbol and those showing dilative response by white
symbols. It is to be noted that those data with smaller values of Sus / p 'C
correspond to loosely prepared samples and with increasing value of Sus / p 'C ,the samples become denser. A line diving the two types of behaviour isdrawn for each of the TC-tests and TE-tests. The two lines thus determinedeach from TC and TE tests are indicated in Figure 16, together with theempirical equations suggested for each of these threshold conditions. The
same data sets are plotted in Figure 17 now choosing the residual strengthnormalized to the initial major principal stress σ '1C . From the two kinds ofplot shown in Figure 16 and 17, the following observation can be made.

Forensic Diagnosis Of Underwater Slope Failure In Jamuna River25

December 2007, Dhaka, Bangladesh

Figure 16: KC-value versus residual strength normalized to the initialmean principal stress – comparison between triaxial
compression and extension tests

Figure17: Factor of safety versus Koch-value or versus angle of slope for
the Jamuna River sandFigure 18: Residual strength ratio SUS / σ '1C versus void ratio-comparison
between triaxial compression and extension tests

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1. In the case when the residual strength is normalized to the initialmean confining stress, the value of Sus / p 'C tends to increase withdecreasing K C -value, and also it depends upon the mode of
deformation as to whether the loading is triaxial compression or
triaxial extension.
2. If the residual strength is normalized to the initial major principal
stress, the value of Sus / σ '1C is determined uniquely irrespective of
the K C -value in the anisotropic consolidation, and also
independently of whether the mode of deformation is triaxial
compression or triaxial extension. For the mica-containing sandfrom the Jamuna River site, the threshold value of the normalized
residual strength separating conditions of contractive and dilative
behaviour is found to be Sus / σ '1C = 0.26 as accordingly indicated in
Figure 17.
3. Each data in Figure 17 belongs to the samples having different void
ratios but close examination of the data has shown, although notshown explicitly, that for the state with a given void ratio, thenormalized residual strength Sus / σ '1C takes a constant valueirrespective of the K C -condition at the time of consolidation. Thus,
the limiting value of Sus / σ '1C = 0.26 can be taken as the upper boundof Sus / σ '1C -values within the range of the void ratio in which thesand exhibits contractive behaviour.
In the type of plot shown in Figure 16 and 17, the looseness ordenseness of the samples is not indicated explicitly. In order to visualize
this effect, the same test data are now shown in Figure 18 in terms of theSus / σ '1C plotted versus the void ratio, e. It may be seen in the figure that
effects of the minor principal stress, that is, σ '3C -value in the TC-test andσ '1C -value in the TE-test, is not so important but the influence of the modeof deformation as to whether it is TC-test or TE-test would be somewhat
significant with the mode of the TE-test giving smaller normalized residual

Figure 19: Forces acting on a soil element above a sliding plane in asubmerged slope

Forensic Diagnosis Of Underwater Slope Failure In Jamuna River27

December 2007, Dhaka, Bangladesh

strength Sus / σ '1C as compared to that from the TC-tests. It is to be noticed
that no matter whether the mode is TC-test or TE-test, the upper limit ofSus / σ '1C takes the identical value of 0.26. The density of each samples
tested is also shown by way of the relative density, Dr, with the scale
indicated on the right hand side of Figure 18. If the average is taken, it canbe conclusively mentioned that, for the Jamuna River sand deposited with arelative density smaller than Dr ≅ 65% , it will exhibit contractive behaviour.
Therefore the in-situ deposits under such condition will have a potential todevelop flow typedeformation irrespective of the K C -condition if it issubjected to an external agency for triggering the slide.

Figure 20: Mohr circle to determine σ 1 and σ 3 from σ α and τ α

9.

SIMPLE ANALYSIS OF THE SLIDE IN JAMUNA RIVER

9.1

Basic Concept

For the sake of simplicity, let a potential sliding plane be located inparallel to the surface of the submerged slope as illustrated in Figure 19.
Then, from the equilibrium of forces amongst the submerged weight of asoil mass and normal and tangential forces N and S acting on the potential
sliding plane, the stresses σ α and τ α are obtained asN= γ ' H cos 2 αlSτ α = = γ ' H sin α ⋅ cos α
l

σα =

(6)

where γ ' is the submerged unit weight of the soil, α is the angle of thepotential sliding plane, and H is the height of the soil mass being considered.
Then, given the values of stress components, σ α and τα , as above, it ispossible to locate a point B in the Mohr diagram as illustrated in Figure 20.
The direction of the line OB indicates the angle of obliquity of stressapplication, α , or the angle of stress mobilization. By drawing a half circle
through the point B so that it is tangential to the line OB, it becomes
possible to identify the points of the major and minor principal stresses σ 1and σ 3 on the Mohr diagram. Then, from geometrical consideration, thefollowing relations are obtained.

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1
)τ α
cosα
1
σ 3 = σ α + (tan α −
)τ α
cos α

σ 1 = σ α + (tan α +(7)Introducing Eq. (6) into Eq. (7), one obtains
σ 1 = γ ' H (1 + sin α )σ 3 = γ 'H (1 − sin α )(8)Thus, the ratio between the minor and major principal stresses is obtained as
Kc = σ 3 / σ 1 =1 − sin α
1 + sin α(9)

The relation of Eq. (9) is displayed in Figure 21. It is known that the
majority of natural slopes consisting of relatively soft soils have an angle
ranging approximately between α = 0 and α = 30°. Thus, the ratio, K C ,between the two principal stresses has a value between 0.3 and 1.0.

Figure 21: Relation between KC -value and angle of slope
9.2

Typical Pattern of Deformation

The typical pattern of undrained deformation of anisotropicallyconsolidated specimens is schematically illustrated in Figure 22 in terms ofstress path and stress-strain curve. In Figure 22(a), the abscissa indicatesthe mean principal effective stress defined by p ' = (σ '1 +2σ '3 ) / 3 and theordinate represents the shear stress defined by q = σ '1 −σ '3 . In Figure 22,
point A indicates an initial state of K C -consolidation whereupon undrained
shear stress application starts. When the specimen is loose, it shows anincrease in deviator stress, q, to a point B at peak strength and then adecrease down to a point C corresponding to the state of phasetransformation or the quasi-steady state. The bent-over in the stress pathtakes place at point C and the shear stress increases to a point D where large
deformation starts to occur without any change in the effective mean stressp’ and shear stress q. This state is called the steady state. When thespecimen is loose, the minimum deviator stress is encountered, concomitant

Forensic Diagnosis Of Underwater Slope Failure In Jamuna River29

December 2007, Dhaka, Bangladeshwith fairly large deformation, at point C where the phase transformation
takes place from contractive to dilative behaviour.

Figure 22: Typical stress-path and stress-strain relation for loosedThus, the residual strength is defined by the shear stress qQS which ismobilized at point C. The residual strength thus defined is called thestrength at quasi-steady state. When the sand is very loose, the gain in thedeviator stress from point C to D is not achieved. The sample continues todeform with a constant deviator stress. In other words, the quasi-steadystate (QSS) becomes coincident with the steady state (SS). In the case of
the Jamuna River sand, the samples are seen deforming at a constantdeviator stress as apparent from the test data shown in Figs. 9 through 11.
This may be due to the inclusion of mica. Thus, in the present study, thequasi-study states will be taken as being identical to the steady state sectionsin the permanent and temporary slopes. Looking over the configuration of
the post-failure slopes, one may envision that the failure was triggered
initially at the toe of the slope and followed by flow-type movement of thesoil behind it. The profiles of slopes shown in Figure 23 through 28
disclose that the soils have slid down the slope through a considerable
distance resulting in thick deposits of debris at the bottom of the dredged
channel. Thus, the post-failure surface in the upper part of the submerged
slope can be considered to have been the plane where the soil mass had
actually slid down. This surface may therefore be considered as the sliding
surface on which flow of liquefied sand had taken place. It is apparent thatthe sliding surface thus determined is inclined with an angle smaller than theoriginal slope angle of 1:3.0 and 1:5.0. However, to simplify calculation, it
may be assumed that the moving surface of the slope during flow with large
deformation was in parallel with the sliding plane, as schematicallyillustrated in Figure 19.

Figure 23: Slide on Dec. 3, 1995 in the permanent slope

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Figure 24: Slide on Dec. 3, 1995 in the permanent slope

Figure 25: Slide on Dec. 3, 1995 in the permanent slope

Figure 26: Slide on Dec. 3, 1995 in the permanent slope

Figure 27: Factor of safety versus Koch-value or versus angle of slope for
the Jamuna River sandForensic Diagnosis Of Underwater Slope Failure In Jamuna River31

December 2007, Dhaka, Bangladesh

Figure 28: Slide on April 20, 1996 in the temporary slope(a) Triggering mechanism
There are several cases of submarine landslides documented inliteratures. One of the large submarine landslides ever reported in details
would be the slide which occurred at the rim of the recent fill towards thesea at the Port of Nice in France on October 16, 1979. The fill, much ofwhich was deposited through or in water, was constructed on a deltaic
deposit of stratified clayey silt and silty sand. Features and some analysis
results are reported by H.B. Seed et al. (1988). Regarding the triggering
mechanism, multiple events were cited to have been possible causes for
initiating the slide. These are (1) the tidal wave first inducing about 3m
lowering of the sea level due presumably to a off-shore landslide and (2) the
increase in an artesian pressure due to rainfalls in the preceding days at
depths of about 40m in the pervious sand layer which is connected withwater levels on land. Thus, it was difficult to narrow down the causes into asingle event.
The clarification of the triggering cause for the slides in the Jamuna
River channel is also a difficult task but the conceivable reasons variously
conceived may be summarized as follows.
1. During the process of underwater excavation, the cutting by adredger might have been carried out so fast that the rapid change
in the state of stress did occur creating a highly undrained
condition with the result that local failure was triggered first andretrogressed into a large slide.
2. In the course of the excavation conducted stepwise, one step of
cutting might have been so large in block that the steep slope
locally created did collapse enlarging the zone of slips into theentire slide.
3. There were natural phenomena frequently occurring in the regionof Jamuna River. These include torrential downpour, wave
actions and falling water levels. None of these phenomena could
be pinpointed as a single cause of excitation, but the effects offalling water level are most likely to be one of the reasons
triggering the slips.

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4. Besides the externally imposed agencies as cited above, there
would be an internal reason. That is the nature of the sand itself
containing the mica mineral as mentioned above. The sand in the
Jamuna River environment must be deposited in a precarious statenarrowly keeping its stability and thus easily susceptible totriggering failure. This aspect was addressed by Kramer and Seed(1988) who asserted that the sand deposited with a large initialshear stress, that is, the one anisotropically consolidated with asmaller Ko-value, the margin of stability is narrow against
additional external agency. This fact holds true for many of sanddeposits, as exemplified by the test data demonstrated in Figure 9
to 11. It may be seen for example that the sand consolidated with
K C =0.5 with the void ratio of 0.875 could collapse if a small
deviator stress of q=10kPa is applied additionally.

Forensic Diagnosis Of Underwater Slope Failure In Jamuna River

33

December 2007, Dhaka, Bangladesh

Among several reasons as cited above, there are not strong reasons in
support of the above hypotheses 1 and 2, that is, the rapid cutting andoverstepping. Once these operations turned out to be undesirable, it is likelythat the operators must have changed the way the cutting was performed.
Therefore the sliding must have been limited to a certain area throughout thelength of the channel. However, the slips did actually occur along the longstretched zone in the channel. This fact appears to indicate that the
hypotheses 1 and 2 are not likely to be the scenario triggering the slips.
It is the authors view that (1) the lowering of water levels and (2) the
potentially susceptible nature of the mica-containing sand put into the K C conditions by excavation are most likely the two major reasons creating
conditions to trigger the failure. Although the scenario is envisaged asabove, it was not possible to come up with a parameter such as factor ofsafety to define the triggering mechanism in a quantitative manner.
(b) Factor of Safety Against Flow Slide
The flow-type failure will be induced in loose sandy deposits, if themagnitude of the residual strength is equal to or smaller than that of theshear stress induced by the gravity force. It is to be mentioned here that,among several external agencies, the gravity-induced stress would be themain force driving the soil mass to move downhill. If the soil deposit werein a loose state exhibiting the contractive behaviour with a residual strength
which is smaller than the gravity-induced shear stress, then the soil mass
would continue to move downwards leading to the follow-type slide. The
deviator stress, qO , applied initially to a soil element at a depth of H under
the submerged slope is evaluated, as follows, with reference to Eq. (8).
qO = σ '1C −σ '3C = 2γ ' H sin α(10)

The residual strength, SUS , in the soil after it has been deformed
largely is known to depend on the void ratio, but if the largest normalized
residual strength, SUS / σ '1C = 0.26, within the range of contractive behaviour
is taken up for consideration, residual strength would be estimated withreference to Eqs. (5) and (8) as
SUS =

qQS
2

⋅ cos φS = 0.26σ 1C = 0.26γ ' H (1 + sin α )(11)

The factor of safety against the flow deformation may be defined as
the ratio between the deviator stress qQS at the steady state and the initialdeviator stress qO as illustrated in Figure 22. With reference to thedefinition given by Eq. (3), the deviator stress qQS = qS is expressed as
qS = 2SUS / cosφ S
and the initial deviator stress is given by
qO = σ '1C −σ '3C = 2γ ' H sin α from Eq. (8). Thus, the facto of safety against
flow is expressed as

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FS =

qQS
qO

=

SUS
1
⋅
γ ' H sin α cosφS(12)Introducing Eq. (11) into Eq. (12), one obtains
FS = 0.26

1 + sin α
1⋅
sin α cos φ S(13)

The factor of safety thus defined is shown plotted in Figure 29 (a)versus the angle of slope α and versus the K C -value as evaluated by Eq. (9).
Individual values Fs obtained from the TC-tests are indicated by circles andthose from the TE-tests are indicated by rectangles.
The plot of Figure 17 showing the relation between K C -value and
SUS / σ '1C is reproduced in Figure 30 where the value of void ratio is indicatedfor each value of SUS / σ 'v = 0.04 , 0.09, 0.15 and 0.26.
It is known from plot of Figure 30 that if the relative density in-situ isassumed to have been Dr ≅ 60% corresponding to e ≅ 0.84 , the residual
strength ratio would have been SUS / σ '1C ≅ 0.15 . For this value, the factor ofsafety is obtained simply by changing the coefficient in Eq. (13) from 0.26
to 0.15. The relation between Fs and K C for such a case is also shown in
Figure 29 (a). The zone enclosed by these two curves is indicated by darkcolor. In the same fashion, the zone corresponding to the residual strength
ratio between 0.15 ( Dr ≅ 60% ) and 0.09 ( Dr ≅ 58% ) is shown in Figure 29(b).
The factor of safety corresponding to smaller value of SUS / σ '1C ≅ 0.04 to 0.09
is shown plotted against K C -value in Figure 29 (c).

10. CONSIDERATIONS FOR INSTABILITY OF UNDERWATERSLOPES IN JAMUNA RIVER BRIDGE SITE
As mentioned in the foregoing section (see Figure 4), the angle ofunderwater slope in the Jamuna River excavation was 1:3.5 in the upper andlower parts on the permanent slope and 1:5.0 in the middle portion. The
slide took place on Dec. 3, 1995 at the cross section 1480, 1500, 1550
within the zone of W3 (see Figure 3) and cross section 1800 in W4 on Dec.
15, 1945. These are shown in Figure 23 to 26. The slide on the temporary
slope occurred in April and May in 1996. Cross section for these slides isshown in Figure 27 and 28.
There are no reliable test data available to assess the relative densityof the field deposit in the Jamuna River bed, but judging from the nature offluvial sediments and from the SPT and CPT data, it is envisaged as shownin Figure 6 that the relative density may be around Dr=50% and more likely
less than Dr=60%. With this assumption in mind, the residual strength of
the sand in Jamuna River may be estimated roughly from the diagram ofForensic Diagnosis Of Underwater Slope Failure In Jamuna River35

December 2007, Dhaka, Bangladesh

Figure 30 in which the normalized residual strength is indicated in terms ofvoid ratio or relative density.
It might be difficult to assess the normalized residual strength only by
way of relative density but if attention is paid to the range in the normalized
0.26, this value seems to be in an appropriate range which is acceptable in
the light of many data on other sands ever obtained. Under theconsideration as above, it may conclusively mentioned that, (1) for the slopewith 1:3.5, the factor of safety could easily be less than 1.0 for the Jamuna
River bed sand with the normalized residual strength less than about
SUS / σ '1C = 0.26 which could most likely to be the case, and (2) for the slopewith 1:5.0 slope, the value of SUS / σ '1C with Fs=1.0 could be read off from
Figure 29(a) as being about 0.15 which could be the case if there exist loose
zones in in-situ deposit.

Figure 30: Void ratio versus the normalized residual strength

Figure 31: Relation between density, SPT N-value and slope
angle for given factor of safety

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The outcome of the evaluation as described above is summed up in the
diagram of Figure 31 where the lines giving a factor of safety FS = 0.9 , 1.0
and 1.7 are indicated in terms of slope angle α and relative density. For
reference sake, SPT N-value converted by the empirical relation isdemonstrated in the ordinate of Figure 31 with the scale indicated on theright-hand side. Eq. (14) is quoted from the study by Cubrinovski and
Ishihara (1999) by assuming that e max − e min = 0.60 . The N1 -value in Eq. (14)indicates the SPT N-value corresponding to an overburden pressure of
1kg/cm2 and also about 80% of the theoretical energy in hammer hitting.
Drawing attention to the line FS = 1.0 in Figure 31, one may recognize thatfor the slope angle between 1:5.0 and 1:3.0, the factor of safety estimatedlies in the zone of instability with FS < 1.0 assuming the relative density
smaller than about 62%.
N 1 = 25(

Dr 2
)
100

(14)

In view of the actual conditions in the field at Jamuna River as
described in the foregoing sections, the results of the simple analysis
summarized in Figure 31 would appear to provide evidences with areasonable level of credibility for the occurrence of the underwater slides on
the excavated slopes in Jamuna River.

11.

CONCLUSIVE REMARKSThe failure of the underwater slopes during the dredging excavation in thesand bar in Jamuna River in Bangladesh was introduced first and then some
speculative reasons for such slips to have occurred were pointed out. To
provide sound basis for interpretation of failure mechanism, results ofmultiple series of triaxial test in the laboratory were introduced with theframework of consistent concept in line with the test results on other sandsin Japan. The main points derived from the tests are summarized as follows.
1. It is known that the sand initially consolidated with higher degreeof anisotropy, that is, with a smaller K C -value, tends to exhibit
more contractive (or collapsible) behaviour when it is deformed
largely into a steady-state. To take into account of this effects, it
was found more appropriate to select the major initial principal
stress, σ '1C , not the mean initial principal stress,
p 'C = (σ '1C +2σ '2C ) / 3 , as an index parameter to express effects ofconfinement. Thus, when the residual strength SUS at the steadystate is normalized to the major principle stress, σ '1C , it takes aconstant value irrespective of K C -conditions.
2. Thus, the normalized residual strength SUS / σ '1C can be expresseduniquely as a function of relative density or void ratio. Within therange of relative density where the behaviour is contractive, theupper limit of the normalized residual strength for the Jamuna

Forensic Diagnosis Of Underwater Slope Failure In Jamuna River37

December 2007, Dhaka, BangladeshRiver sand is SUS / σ '1C = 0.26 and this value is encountered when
the sand is deposited at a relative density less than approximately
Dr=65%. On the basis of the SPT and CPT data, the in-situ
relative density at the site of Jamuna River was found to be
somewhere around Dr=50% which is less than 65%. This fact
implies that the in-situ deposit is within the range of density where
the sand exhibits contractive behaviour indicating highsusceptibility to flow type deformation once the slip is triggered.
3. On the other hand, the slope angle of dredged channel in Jamuna
River at the time of sliding is known to have been 1:3.5 ( ≅ 16
degree) and 1:5.0 ( ≅ 11.31 degree). By assuming the slides tohave occurred on the straight-line sliding plane which is parallel tothe surface of the slope, it was possible to assess the magnitude ofshear stress and the major principal stress σ '1C which wasmobilized in the sand deposits in the slopes excavated with theangle of 1:3.5 and 1:5.0.
4. By comparing the magnitude of shear stress assessed as above withthe value of residual strength evaluated from the laboratory tests, it
was found that the existing shear stress must have become greaterthan the residual strength available at the riverbed deposit, if thein-situ sand were deposited with a relative density in the range lessthan about 60%.
5. It is to be noticed here that for other sands in Japan, the upper limit
of density showing contractive behaviour is, by and large, smaller
than Dr=50%. This implies that only loosely deposited sand with arelative density less than 50% could develop flow type
deformation and therefore such a sand is identified potentiallymore stable. In contrast, with a higher value of upper-limit density
such as the mica-containing Bangladesh sand, the likelihood ishigh for in-situ deposits to exist with a relative density less thanthe upper limit. Thus, such sand is to be identified as potentiallyunstable. In the sense as above, the identification of the upper
limit density or threshold density differentiating between
conditions of contractive and dilative behaviour of a given sandwill pose a important challenge in future development in this areaof soil mechanics.

ACKNOWLEDGEMENTS
The study described in this paper was initiated by the first author who paid avisit of inspection to the Jamuna River site upon recommendation byProfessor W. Van Impe, Past president of ISSMGE. The engineers of
HAM-van Oord were kindly showed the author around the site. The triaxial
tests in the laboratory were carried out by Mr. Y. Nakayama and T.
Shibayama who were graduate students at the Tokyo University of Science.
The authors wish to express their sincere gratitude to the persons cited
above.

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REFERENCES
Chern, J.C. (1985), Undrained Response of Saturated Sands with Emphasis
on Liquefaction and Cyclic Mobility, Ph. D. Theses, University of
British Columbia, Vancouver.
Cubrinovski, M. and Ishihara, K (1999), Empirical correlation between SPT
N-value and Relative Density for Sandy Soils, Journal of the Japanese
Geotechnical Society, Soils and Foundations, Vol. 39, No. 5, pp. 61-71.
Hight, D. W., Georgiannou, V.N., Matin, P.L. and Mundegar, A.K. (1999),
Flow slides in Micaceous Sands,” Proc. International Symposium on
Problematic soils, Sendai, Japan, Vol. 2, pp. 945-958.
Ishihara, K. (1996), Soil Behaviour in Earthquake Geotechnics, Oxford
Clarendon Press, pp. 259-260.
Ishihara, K., Tsukamoto, Y. and Shibayama, T. (2003), Evaluation of Slope
Stability against Flow in Saturated Sand, Reports on GeotechnicalEngineering, Soil Mechanics and Rock Mechanics, Vol. 5, Jubilee Vol.
of 75th Anniversary of K. Terzaghi’s Erdbaumechanik, pp. 41-54.
Kato, S., Ishihara, K. and Towhata, I. (2001), Undrained Shear
Characteristics of Saturated Sand under Anisotropic Consolidation,
submitted to Soils an Foundation, Vol. 41, No. 1, pp. 1-11.
Kramer, S.L. and Seed, H.B. (1988), Initiation of soil Liquefaction under
Static Loading Conditions, Journal of Geotechnical Engineering
Division, ASCE, Vol. 114, No. 4, pp. 412-430.
Seed. H. B., Seed, R.B., Schlosser, F., Blondeau, F. and Juran, I. (1988),
The Landslide at the Port of Nice on October 16, 1979, Report No.
UCB/EERC-88/10, University of California, Berkeley.
Tsukamoto, T., Ishihara, K. and Kamata, T. (2007), Residual Strength ofSoils under Flow Deformation in Triaxial Tests, submitted to a journal.
Vaid, Y.P. and J.C. Chern, J.C. (1985), Cyclic and Monotonic Undrained
Response of Saturated Sands, Advances in the Art of Testing Soils
under Cyclic Condition, Proc. of ASCE Convention in Detroit,
Michigan, pp. 120-147.

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DISTRESS IN THE TARMAC AT NEWLYOPENED SUVARNABHUMI AIRPORTWORSAK KANOK-NUKULCHAI
Dean of the School of Engineering & Technology
Asian Institute of Technology
worsak@ait.ac.th
ABSTRACTThe investigation by Engineering Institute of Thailand (EIT) revealed
that the damage was caused by the premature failure of asphalt base course
due to the separation of asphalt binder from aggregate surface in thepresence of moisture, commonly known as "stripping". It was quite evident
from the milled damage area that water seeped from the sand blanket
underneath the cement-treated base (CTB) through expansion joints. The
core samples of the asphalt concrete pavement from damaged area show
evidence of asphalt stripping at the base course, a typical effect of soaking
water, while core samples from undamaged areas show good condition. In
order to prevent further distress in the Tarmac, as the airport site is locatedin the floodway of Bangkok's eastern suburbs, it requires both effective
flood protection and drainage systems to avoid problems caused by water
seepage into the sand blanket under the airport's taxiways and runways.

1. INTRODUCTION
Last October, when the first sign of rutting was spotted in five of the six
taxilanes and in one taxiway at the Suvarnabhumi International Airport, theEngineering Institute of Thailand (EIT) assigned a team of experts to join
the preliminary investigation. The investigation revealed that the damage
was caused by the premature failure of asphalt base course due to theseparation of asphalt binder from aggregate surface in the presence ofmoisture, commonly known as "stripping". It was quite evident from themilled damage area (Figure 1) that water seeped from the sand blanket
underneath the cement-treated base (CTB) through expansion joints.
The key question is: How, and also how long, has the water been
trapped in the sand blanket?
This article intends to provide technical facts to the readers who wantto understand what really happened to the airfield pavement of this brandnew airport.

41

December 2007, Dhaka, Bangladesh

Figure 1: Milled asphalt at the damaged Area

2. WORRYING OBSERVATIONS
On 27 October 2006, about 2-3 weeks after the official opening of the
airport, the first signs of distress were spotted at several locations in the
taxiways and taxilanes, in the form of rutting, rutting with shattering andsplit, and rutting with hairline cracks (Figure 5). Since then, a similar patternof failure has developed heavily in five of the six taxilanes and along theeast parallel taxiway. Although both runways are still in good structural
condition, plastic deformation of the asphalt wearing course was observed
near the takeoff position. The extent of the damage is summarised in
Figure 2.

Figure 2: Illustration of taxiways and taxilanes

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Figure 3: Overview of east runway, taxiways and the drainage system
Suvarnabhumi airport covers an area of 20,000 rai (3,200 hectares). In
its first phase, the airfield serves its hourly 112 flights with two runways, six
taxiways and six taxilanes (Figure 3). The tarmac (Figure 4) consists ofthree layers of asphalt concrete, namely the base course (23 cm thick), thebinder course (6 cm thick), and the wearing course (4 cm thick). Underneathare four layers of the cement-treated base (CTB), 18 cm. thick each, sitting
on top of the sand blanket (approximately 80 cm thick) left over from theground improvement process.

Figure 4: Structure of taxiway pavement
Plastic deformation was observed on the wearing course at the turnaround segment of the taxiway leading to the takeoff position of the runway(Figure 6). This location is normally under maximum load when the planetakes off with a full load of fuel. The high shearing stress that causes plastic
deformation was imposed by braking, accelerating or turning traffic. Plastic
deformation is greatest at high temperatures, especially for the AC 60/70
binder grade used in this case. The occurrence of the plastic deformation at
this location is therefore a common phenomenon and only routine
maintenance is required to repair this type of distress. Aside from thissurface distortion, both runways are in good structural condition.

Distress in the Tarmac at Newly Opened Suvarnabhumi Airport

43

December 2007, Dhaka, Bangladesh

Figure 5: Typical distress in the taxiways and taxilanes.

Figure 6: Surface deformation of the runway.
Initial investigation was made by coring the asphalt concrete
pavement at a diameter 100 mm throughout its 33 cm thickness from thedamaged areas (Figure 3). The following observations can be made:
-

-

-

-

44

All core samples from damaged area show evidence of asphalt
stripping at the base course, a typical effect of soaking water, while
core samples from undamaged areas show good condition.
The water had infiltrated into and confined in the asphalt concretebase course for a long period. Thus, the base course has been
immersed in and impaired by the water.
As a result of asphalt stripping, asphalt binder was separated fromaggregate surface, leading to premature loss of strength and stabilityof the base course.
The load of the aircraft had then impaired the failed asphalt concrete
pavement, causing rutting on the surface.

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Based on the core samples, laboratory tests have indicated the correct
job mix and aggregate gradation of the asphalt concrete material. This was
also confirmed by a separate test at the Highway Department.
To expose the cement-tested base (CTB) for visual inspection, an areaof asphalt concrete pavement was milled at the damaged area of thetaxilane. It was evident that there was no sign of damage or subsidence in
the CTB. However, traces of water seepage were clearly observed (Figure 7)
along the rim of the expansion joints in the CTB. This evidence of seepage
further hinted that a large quantity of water might still be trapped in the sandblanket.

Figure 7: Illustration of milled pavement in the taxilane T11, a core sample ofasphalt concrete, trace of the water seepage at CTB joint and the test pit.
On January 31, a test pit (Figure 7) was dug on Taxiway T11, where
damage was found to be extensive. After the excavation went through CTB
and exposed the top surface of the sand blanket, water seeped through thesand immediately until the water level reached about 20 cm above the sandblanket (or roughly at +0.0 MSL). The water stayed at that level even whenattempt were made to clear the water.
Interestingly, to prove that water in the sand blanket is fully confinedwith no connection outside, a deep excavation was made nearby, but outside
the pavement area (Figure 8). After the excavation, the dug hole wascompletely dry. No sign of water from the sand blanket had receded into
this empty hole.

Distress in the Tarmac at Newly Opened Suvarnabhumi Airport

45

December 2007, Dhaka, Bangladesh

Meanwhile, Highway Department experts have tested the samples ofsand and CTB from this test pit and reported that all materials tested have
met the standards.

Figure 8: Excavation to test the connectivity of the trapped water

3.

HOW WAS THE WATER TRAPPED?

Based on the official report of the investigation committee appointed by
Airports of Thailand Public Company (AOT), the following reasons had
been given for the trapped water:
1. Runoff of rainfall water was collected and retained within the
airport compound in the pockets of sand used to fill fishponds,
swamps and waterways prior to the airport construction. Waterfrom this source might find its way into the sand blanket.
2. Surface water spilled from the drain age canals, during the flooding
period, over the top soil around the unpaved neighbourhood into
the sand blanket.
3. Surface water once trapped underground was not able to escape dueto the lack of a subsurface drainage system. This was aggravated by
the blockage of culverts and other underground structures.
4. Based on soil boring records, thin sand layers may exist originallywithin the soft clay layer at a level about 10 metres deep. Some ofthese sand layers may cross path with the leftover PVD, thus
allowing running shallow ground water to seep upward into thesand blanket.
On the last point, some geotechnical experts argued against thispossibility. At the end of the PVD preloading, the extra surcharge consistingof crushed rocks was removed. Thus, it is no longer possible for water tomove up to the surface through the PVDs against the hydraulic gradient andagainst gravity at the end of consolidation process.
In addition, there is hydraulic back-pressure from the trapped water inthe sand blanket making it impossible for such hydraulic upward flow to
occur.

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Because the airport site is located in the floodway of Bangkok's
eastern suburbs, it requires both effective flood protection and drainage
systems. The aim is to prevent flooding from flash floods, as well as to drainaway rainwater in the catchments of the airport compound. The design ofthe polder system includes the perimeter polder dike, internal drainage
system, two pumping stations and a perimeter road (Figure 9).

Figure 9: Profile of the flood protection and the drainage system.
Basically, the internal drainage system for runoff water consists of:
1. The unlined primary canals and reservoirs both with the bed at 1.90 m MSL. Based on the design criteria, water level in the
primary canals and reservoirs must be maintained not higher than 1.40 m MSL.
2. The secondary canals with concrete linings. The canal bed of thesecondary canal is -1.15 m MSL. It is designed to be dry except
during the raining.
The primary and secondary canals are interconnected by ditches toensure that the runoff water from the pavement area will flow under gravity
towards the two pumping stations located at the south corners of the site. In
the operating manual, water in the primary canals and reservoirs must
always be controlled at the pumping stations to ensure that the water level ismaintained at -1.40 m MSL or lower.
With the design assumption that no rain water runoff can leak into thesand blanket, no subsurface drainage system exists to systematically drain
trapped water from the sand blanket. This might be a weakness in the design
criteria of the airfield pavement.

4.

GROUND IMPROVEMENTS

Suvarnabhumi Airport compound is situated on formerly agricultural land,fish farms, swamps and waterways. A thick deposit of soft clay is foundover 10 metres deep, with 100-120% water content, on top of medium stiffclay and stiff clay with water content of 50-90% and less than 50%
respectively.

Distress in the Tarmac at Newly Opened Suvarnabhumi Airport47

December 2007, Dhaka, Bangladesh

Soil is a multiphase system, comprising a solid phase (soil particles)
and a fluid phase (air and water) called the pore fluid. For soft clay, thehigher the volume of the fluid phase, the weaker and more compressible thesoil mass. Therefore, any reduction of water in the pores of the soil, which
decreases the volume of the soil mass (Figure 10) and subsequently
increases the particle-to-particle contact, increases the strength of the soil
and reduces its compressibility at service stage.
To be suitable for airfield pavement, pore water in the soft soil must
be squeezed out to result in water content around 80%. Thus, the soft clay istransformed into medium stiff clay. This consolidation process can be
accelerated by a modern technique using Prefabricated Vertical Drains(PVD).

Figure 10: Natural and consolidated soft clay deposits.
PVD is a plastic tube core wrapped in a filter jacket, made of nonwoven polyester or polypropylene geotextiles or synthetic paper. PVDs
drain soil by squeezing out pore water, a process that can be accelerated byadjusting the spacing of PVDs. In this process, water flows a lot more
quickly horizontally towards the drain and then vertically along the drains
towards the permeable drainage layer at the top. The step-by-step procedureof consolidation using PVD is illustrated in Figure 11.

1

4

2

5

3

6

Figure 11: Consolidation process of soft clay under the airfield pavement

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5.

WHAT'S NEXT?

In its press release issued on 15 February 2007, the Engineering Institute ofThailand (EIT) strongly recommended that, similar to a first-aid treatment,
trapped water should be drained out urgently to minimise the potential
spread of cracks on taxi lanes, taxiways, and even on runway. This
immediate action should be carried out with the consent and cooperation of
all concerned parties including the project management consultants, thedesigners and the contractors.
Alternatively, the AOT should seek temporary protection from thecourt to implement the required first-aid treatment without damaging its
rights under the contract. Meanwhile, it was reported that the AOT plans tocommission a team of international experts to carry out an in-depth
technical investigation in order to recommend long-term remedies.

Distress in the Tarmac at Newly Opened Suvarnabhumi Airport49

December 2007, Dhaka, Bangladesh

50

New Technologies for Urban Safety of Mega Cities in Asia

SAFETY PROBLEMSRELATED TO DETERIORATION
OF CONCRETE STRUCTURESTAKETO UOMOTO
Professor, Civil Engineering Department,
Faculty of Engineering, Shibaura Institute of Technology, Japanuomoto@sic.shibaura-it.ac.jp
ABSTRACTThe maintenance of concrete structures is essential and important tomaintain the safety of urban area. Most of the political, economical andeducational activities of a country are concentrated in urban area. If any
accident or hazard occurs, the effect is tremendous. Concrete structures are
durable and people easily forget about the durability aspects of concrete
structures. It is very important for both the owners and engineers torecognize how important it is to maintain concrete structures to keep the
people safe in urban area. Before any accident of hazards happens, weshould keep eyes to the maintenance of concrete structures. This paper
describes what we are doing in Japan to maintain the existing concrete
structures.

1. INTRODUCTION
Up till now in Japan, the economic growth was rapid in the period of 1960
～ 1980. More than 100million cubic meters of concrete were used toconstruct the structures such as buildings, bridges, tunnels, dams, etc. tosupport the activities of Japanese people. As a result, these infrastructures
rapidly reached 50 years in service, and due to deterioration of the structures,
maintenance of these structures has become a major interest among theowners and the civil engineers.
On the other hands, population of Japan will reduce from now on
because of fewer babies in a family approximately 1.2 children per one
family. Although high technologies have been developed in recent years, it
is sure that fewer engineers have to take care of the huge amount ofstructures from now on, which has never experienced in the past. Due toreduction in the economical growth, the budget for both construction andmaintenance will be reduced in the future. The maintenance of existing
structures must be done with the following conditions: 1) rapid increasing of
the amount of existing structures reaching to the age of 50 years, 2) lessamount of engineers to maintain the structures, 3) less amount of budget canbe used to maintain the structures. .

51

December 2007, Dhaka, Bangladesh

Although there are many hazards in each country, concrete structures
are expected to be safe for long period of time. Main hazards for the
structures in Japan are as follows:
1.
2.
3.
4.
5.
6.

Earthquake and volcanic action
Landslide and flood
Typhoons and strong windFire and Thunder
Accidents
Terrorism

If the structure is deteriorated before the hazards, the structure mayeasily collapse and difficult to maintain the safety of the people. The Figure
1 shows an example of a collapsed pier during Hanshin Awaji Great
Earthquake. As shown in the photo, the pier was deteriorated to large extent
due to alkali aggregate reaction. Concrete is cracked severely and is justlike a bundle of concrete blocks.

Figure 1: Collapsed reinforced concrete pier affected by alkali aggregate
reaction
In order to keep the safety of urban area, it is important to study andinvestigate not only on hazards but also on durability aspects of existing
structures. Even a small amount of concrete spalling may cause traffic
accidents to large extent as we experienced in Sanyo-Shinkansen in 1999.
Considering these situations now, this paper explains what ishappening now in Japan and how we are dealing with the problems throughresearches and engineering.

2. GENERAL MAINTENANCE METHODS BEING USED UP TILLNOWThe maintenance of concrete structures has been done mostly by the ownersof the structures. In case of public structures, the ministries, etc. maintainthe structure after the structures are completed. For the time being, the52

New Technologies for Urban Safety of Mega Cities in Asia

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methods for the maintenance differ according to the owners of the structures.
Although there are some differences, the main concept of the maintenancecan be summarized as follows (Uomoto and Misra, 2001):
1. Periodic inspection and evaluation of deterioration degree
2. Detailed inspection and decision making
3. Repairing and strengthening of deteriorated structures
For periodic inspections, the inspectors inspect the structures visually,sometimes with the help of binoculars and hammers, once a year or once inseveral years according to the importance and time after the structure iscompleted. The inspectors are mostly trained engineers with experiences.
The detailed inspection is done when the estimated degree of deterioration
exceeds certain limit, or when some new phenomenon is found during theperiodic inspection. The detailed inspection is done by visual inspections
with the aid of non-destructive tests or taking core samples out from theinspected structure. The purpose of the inspection is to decide the cause of
the deterioration and also to evaluate whether repair and/or strengthening isneeded or not.
To repair or strengthen the existing structures, it is important to designand select sufficient methods and materials. The most popular repair
method for corrosion of steel bars due to carbonation is to eliminate thecarbonated concrete and replace it by new concrete and apply coatings withand without FRP sheets. But in case of steel corrosion due to chlorides fromthe surrounding environment, the highly chloride concentrated portion of
concrete are taken out, anti-corrosive treatment is applied to the surface ofthe bar, and polymer cement mortar is generally used to repair the concrete
before coating the concrete surface.

3. NEW STANDARD SPECIFICATIONS OF JSCE
After the investigations of many deteriorated concrete structures, theimportance of durability was fully recognized by the civil engineers. To
deal with the problem not only JSCE, AIJ, and JCI recommending methods
to deal with the problems but also the Ministries, and other authorities
started to propose practical counter measures to cope with the situation. As aresult, a large amount of researches has been done related to the durabilityof concrete structures including non-destructive inspection methods.
Among these authorities, the Concrete Committee of JSCE, theleading committee in the field of concrete in Japan, has published thetranslated version of “Standard Specifications for Concrete Structures-2002”
in English to deal with the problems of durability (JSCE, 2005a, 2005b and2005c). The concept written in the specifications will surely be adopted byother institutions.
The main proposals of the “Standard Specifications” are the following
two items:

Safety Problems Related to Deterioration of Concrete Structures53

December 2007, Dhaka, Bangladesh

1) Propose a new method to design and construct new concrete
structures that can be used for specified lifetime without large
amount of maintenance cost.
2) Propose an effective and economical system to maintain existing
concrete structures with small number of engineers and workers.
To deal with the problems for the items 1) and 2), the following two
Specifications are published:
1.

The Standard Specification for Concrete Structures-2002“Structural Performance Verification” (JSCE, 2005a)
2. The Standard Specification for Concrete Structures-2001“Maintenance” (JSCE, 2005b) and3. The Standard Specification for Concrete Structures-2002“Materials and Construction” (JSCE, 2005c)
The concepts of the new Standard Specifications are briefly explainedin the following chapters.
3.1

Durability design of concrete structures for new structures

Performance-based durability design was introduced to “Standard
Specification of Concrete Structures” by the Concrete Committee of JSCEin the year 2000 and be translated to English version in 2005 (JSCE, 2005c).
Although durability of concrete structures was considered important in theprevious specifications, performance-based design method was not used.
The previous specifications described the importance of durability byproposing that the concrete structures are durable for a long time when
specified materials, mixes, covers, etc. are used. But these specifications
did not mention about the duration of service time, etc.
The proposed performance-based new durability design can besummarized as follows:
1. The concrete structure must be quantitatively checked whether the
structure possesses required performance within the designed
period.
2. The degree of deterioration of the structure in service on specified
cause must be specified.
3. To maintain the structure above the specified degree ofdeterioration, the required performance must be specified.
To examine the performance on durability, a kind of limit state design
scheme was introduced for the durability of concrete structures. The
equation can be written as shown in Equation (1):γ i ⋅ Ad A

≤ 1.0

(1)

lim

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Where, Ad is designed performance of the structure at specified time
considering the specified deterioration cause, Alim is limit of theperformance of the structure, and γi is coefficient of the structure
considering the importance, etc.
Generally, performance of concrete has to be verified to satisfy therequired performance. Not only resistances against deterioration but alsomechanism properties of concrete have to be verified as shown below (JSCE,
2005c).
1. Compressive strength
2. Carbonation rate
3. Diffusion coefficient of chloride ions in concrete
4. Dynamic modulus of elasticity
5. Resistance to chemical attack
6. Resistance to alkali aggregate reaction
7. Coefficient of water permeability of concrete
8. Fire resistance
9. Adiabatic temperature rise
10. Drying shrinkage characteristics
11. Setting characteristic
The Figure 2 shows an example of the calculated result for minimum
cover thickness to prevent carbonation induced corrosion at different yearsof service for OPC concrete and BFSC concrete. As shown in the figure,the cover thickness required changes according to the type of cement to be
used, water-cement ratio of concrete, years of service and exposed condition(wet or dry) of the structure to be constructed. When the structure isdesigned for long period of time, the cover thickness may become too large,
and it is recommended to use other countermeasures such as Epoxy-coated
bars.
3.2

Methods of maintenance newly proposed by JSCE (JSCE, 2005b)

The methods used in the new Standard Specification are basically thesame as the conventional method. The differences are that the new method
requires to maintain the structure within their required performances
throughout their service life. Firstly, the listed below issues have to beclearly specified.
1. To maintain a structure, performances required for the structure
must be clearly defined.
2. The performances required for general structures are “safety”,“serviceability”, “hazards to the public”, “aesthetics andlandscape” and “durability”.

Safety Problems Related to Deterioration of Concrete Structures

55

Concrete cover thickness (cm)88
普通ポルトランドセメント

OPC

7Service time
( Years )

66
5

100
100年
75
75年
50
50年
100
100年
75年
75
50年
50
30年
30

44
3

22

乾燥し難い環境，北向きの面など（R=1.0）

Wet Environment

乾燥しやすい環境，南向きの面など（R=1.6）

1

Dry Environment

00
40
40

45

50
50

55

60
60

65

Water
cement（％）
ratio (%)
水セメント比7070Concrete cover thickness (cm)

December 2007, Dhaka, Bangladesh

88
Service time
(Years)100
100年

高炉セメントＢ種

766（スラグ40％）
Blast
Furnace
Slag Cement

75
75年

5

50
50年
100年
100
75年
75
50年
50
30年
30

44
3

22

Wet environment

乾燥し難い環境，北向きの面など（R=1.0）
乾燥しやすい環境，南向きの面など（R=1.6）

1

00
40
40

Dry environment
45

50
50

55

60
60

65

70
70

Water
cementratio (%)
水セメント比（％）

Figure 2: Calculated results of concrete cover according to JSCE Standard
Specification (JSCE, 2005c)
And the basic principles of maintenance works are as follows:
1. Structures must be maintained according to a designatedmaintenance category by formulating a maintenance program toretain the performance within the specified tolerances
throughout their service life. And maintenance system includes
adequate “initial inspection”, “deterioration prediction”,“inspection”, “assessment/judgment”, “remedial action”, and“record”.
2. To maintain a structure, in addition to the assessment andevaluation at the time of inspection, assessment and evaluationmust be made throughout the service life of the structure basedon prediction of deterioration.
3. To predict the deterioration, required performances of thestructure must be clearly defined, and also the design service life
must be made clear.
4. The records on design, construction, initial inspection,
deterioration prediction, periodical inspection, assessment
and/or evaluation, and remedial actions must be kept throughout
the service life.
Standards for maintenance of concrete structure deteriorated bydifferent mechanisms are also discussed. The lists below are the standard
maintenance method published in this standard:
1. Standard maintenance method for carbonation induced
deterioration
2. Standard maintenance method for chloride induced deterioration
3. Standard maintenance method for frost attack
4. Standard maintenance method for chemical attack
5. Standard maintenance method for alkali aggregate reaction

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6. Standard maintenance method for fatigue of RC slab of roadbridge7. Standard maintenance method for fatigue of RC beam of railway
bridgeIn detail for an example, the standard method for chloride induced
deterioration recommends the model to predict chloride ion diffusion,
progress of steel corrosion, and correction of the prediction. Also themethods of initial inspection, routine inspection, periodic inspection, anddetailed inspection as well evaluation and judgment method are also
discussed. Finally, recommendation of selection of remedial measurement
both of repair or strengthening is given also the information has to berecorded.

電流量
Ik (mA/cm)
Current
Amperage(mA/cm)One of the difficulties is how to predict the degree of deterioration at
the end of their service life. There are several researches being done topredict the deterioration in numerical manner (JSCE, 2005b). In the
published Standards, several numerical prediction methods are introduced as
references for structures suffering cyclic fatigue loads, carbonation induced
corrosion and chloride induced corrosion. In case of cyclic fatigue, S-N
curves are used to predict the service life. In case of carbonation induced
and chloride induced corrosion of steel bars, diffusion equations for carbon
dioxide and chloride are used to predict the degree of corrosion. Using
these prediction methods, deterioration degree can be estimated to certain
degree. (See Figure 3) But for other deterioration problems, which has notbeen studied numerically, a quantitative model has not been proposed yet.
To deal with the problem, a qualitative method “Grading method” isintroduced in the Standard.
（Temperature:20℃、Crack depth: 7cm）

0.1

Crack

Cathode

0.05
0
-0.05

days
28日
days
91日
180日days

Anode

-0.1
-0.15

year
1年
years
2年

-0.2
-0.25
0

2

4
6
8
10
モデル端部からの距離(cm)
Distance (cm)12

14

Figure 3: Quantitative prediction of corrosion in marine environment withcracks (Tsukahara et al., 2000)

Safety Problems Related to Deterioration of Concrete Structures57

December 2007, Dhaka, Bangladesh

4. PROBLEMS IN ACTUAL EXISTING STRUCTURES
When a civil engineer is asked by the owner to check the safety of an old
existing structure, one of the largest problems is that there are neither
drawings nor construction records of the structure available. No problem
may occur in case of important facilities, which is maintained with greatcare. But in case of normal structures, the owners do not know theimportance of these documents.
To deal with the problem, NDI is not enough. Fortunately, ourstructures are not too old, and they are mostly designed and constructed by
the method specified by JSCE, AIJ or other associations. Considering these,
the only way is to re-design the structure again using the methodologies
used at the time of construction. Figure 4 shows an example of re-designed
bridge pier constructed about 35 years ago. From the figure, it is mucheasier for a civil engineer to check the safety of the structure under several
hazards. It will become more important for the owners and engineers tokeep these documents throughout the service life of a structure.

D131201907,300

850 65 0
D16

4,500

65 0
4,500

25 0
D25

1, 0003 00

12 023 0

21@300１

1,300

280 8@200

210

50 280 9@200

18,390CL

9,390
280 16@200280

120@125
15,620120

Figure 4: Re-designed reinforced concrete pier of a bridge (Okazaki, 2005)

5. CONCLUDING REMARKS
Engineering is not always complete, and further research works are needed.
To sustain existing structures, durability of the structure is important. One
good method is to construct durable structures, but for the existing
structures maintenance is the only way to deal with the problem. Althoughconcrete committee of JSCE has set up a good system for maintenance ofexisting concrete structures, there are still many things to be done: not only
researches but also education to the students and engineers about durability
and maintenance. I hope this paper may become a help to the concrete
engineers of the world who are trying to design, construct and maintainconcrete structures.

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REFERENCES
JSCE, 2005a. Standard Specifications for Concrete Structures-2002“Structural Performance verification”. JSCE, Tokyo.
JSCE, 2005b. Standard Specifications for Concrete Structures-2001“Maintenance”. JSCE, Tokyo.
JSCE, 2005c. Standard Specifications for Concrete Structures-2002“Materials and Construction”. JSCE, Tokyo.
Okazaki, S., 2005. Development of monitoring system for RC bridge basedon restoration design method. Thesis submitted to the University ofTokyo for Master of Engineering degree.
Tsukahara, E., Koyama, R., Hoshino, T., and Uomoto T., 2000. Estimation
Method of Corroded Portion of Reinforcing Steel Bar by Natural
Potential Measurement. Non-destructive Testing in Civil Engineering
2000, Elsevier.
Uomoto, T., and Misra S., 2001. Role of Engineers to Improve Quality ofConcrete Structures. Proceedings of EASEC-8, Singapore.

Safety Problems Related to Deterioration of Concrete Structures59December 2007, Dhaka, Bangladesh

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New Technologies for Urban Safety of Mega Cities in Asia

PROPOSAL OF A SUSTAINABLETSUNAMI DISASTER MITIGATION SYSTEMFOR THE INDIAN OCEAN REGIONKIMIRO MEGURO1 and MASASUKE TAKASHIMA2
1)
International Center for Urban Safety Engineering
Institute of Industrial Science, The University of Tokyo, Japan
2)
Collage of Environment and Disaster Research
Fuji Tokoha University, Shizuoka, Japan
ABSTRACT
Triggered by a M9.0 earthquake that occurred along the Sunda
Trench, Off-Sumatra, at 07:58 (local time), on December 26, 2004, a hugeand devastating tsunami hit the Indian Ocean Rim countries, causing
unprecedented disaster with over 300,000 dead and missing persons. The
analysis of other potential tsunami scenarios in the region has revealed that
1.3 million dead and missing people may be expected, at worst. Therefore,
an effective and sustainable framework against tsunami disaster is
indispensable in this region.
Land use control, i.e. preventing people from residing next to theshore, is one way to mitigate tsunami disaster if people follow it. However,this is not always a proper option in the Indian Ocean Rim region where theeconomic activities, e.g. fishing, tourism, take place directly next to theseaside. For this case, a New Tsunami Disaster Mitigation System bycombining a reliable warning system and proper evacuation facilities is
proposed. Important characteristics of this system are its simplicity,
economical efficiency and daily-usability.
This paper introduces the New Tsunami Disaster Mitigation System,
highlighting its strengths and the works necessary for its implementation.

1. INTRODUCTION
Triggered by the M9.0 Earthquake that occurred along the Sunda Trench,
Off-Sumatra, at 07:58 (local time), on December 26, 2004, a huge anddevastating tsunami hit the Indian Ocean Rim countries, causing
unprecedented disaster with over 300,000 dead and missing persons. The
tsunami was triggered by one of the possible earthquake scenarios along the
Sunda Trench. Four other potential earthquake events along the trench havebeen identified and the expected number of casualties in case they occur has
been estimated. As a result, it was revealed that 1.3 million dead andmissing people are expected, at worst, as shown in Figure 1. This number isseveral times larger than the observed in the December 26, 2004 event,showing that an effective and sustainable framework against tsunami
disaster is indispensable in this region.

61

December 2007, Dhaka, Bangladesh

Max. Wave HeightDec.26,2004
Indian Ocean
Earthquake Tsunami

①

[m]
19.28

0.00

Population Density[person/km 2]
150,000
0

Fault of Indian Ocean
Earthquake, Dec.26, 2004

②

0

1,000

3,000 [km]Max. Wave Height

Main shock
After shock[m]

Scenario ①

③

12.61

④

Plate boundary

0.00

Population Density[person/km 2]
150,000

by Dr. S. Koshimura, DRI, Kobe(a) Scenario Faults (① - ④) along the Sunda Trench
0

Indian Ocean
Earthquake andTsunami Disaster

200

400

600

800

0

[Unit:1000 person]
1,000 1,200 1,400(Dec.26, 2004)

0

1,000

3,000 [km]Max. Wave Height

Scenario ③

Scenario ①

[m]
28.61

0.00

Population Density

Scenario ②[person/km2]
150,000
0

Scenario ③

Scenario ④
by Drs. S. Koshimura and M. Takashima(c) Estimated Death Toll and Missing Persons
due to Different Scenario Faults

Tsunami Simulation: by Dr. S. Koshimura
Population Distribution: by Oak Ridge National Laboratory 0

1,000

3,000 [km](b) Population Distribution and Estimated Maximum Wave Heightbased on Numerical Tsunami Simulation for the 2004.12.26
Earthquake and Different Earthquake Fault Scenarios (① and ③)

Figure 1: Estimated damage based on numerical tsunami simulation
with possible fault scenarios along the Sunda TrenchSome countries along the Indian Ocean Rim have established atsunami disaster mitigation system based on land use, i.e. prohibiting people
inhabiting next to the seaside. Others are planning to adopt similar measures.
Land use control is an efficient measure if people follow it. However, this is
not always a proper option in case activities such as fishing and tourism,
which are the pillars of the region economy, take place directly next to theshore. Under these conditions, it is inapplicable to implement land use
control policies.
In the Pacific Ocean Rim region, tsunami disaster mitigation relies ona sophisticated warning system, which is used not only for disastermitigation but also for earth science research. This system is costly in termsof both installation and maintenance. Furthermore, it requires a great deal ofknowledge to operate it. Although it is very useful and appropriate for thisarea, where countries with financial and technological resources such as US
and Japan are located, it is not applicable for the Indian Ocean region(Figure 2).
Taking the above mentioned points into consideration, a New
Tsunami Disaster Mitigation System which combines a warning system
suitable for the Indian Ocean region and proper evacuation facilities interms of location, strength and sheltering capacity is proposed. With thissystem there is no need to relocate the people living along the seashore;

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therefore, there is no impact on the local economies. The proposed system issimple, economically efficient and daily-usable.

Tsunami Warning System(TWS)
Conventional
TWS

Proposed
New TWS
Low Cost, Simple and Daily Useable

Sophisticated but Expensive and Complicated

The minimum unit of the proposed system
would be one or two simple multi-purpose
observation buoys with solar battery
system operated by one beach society,such as hotel resort society or its network.
temperature, current velocity, wave
height, moisture, etc. on a daily basis

Redundant and easier/cheaper to sustain
Because of more and simpler stations
With daily usability,
Weather forecast, Safety information,
Break unscientific rumor
Prediction of catch of fish, Fish dude ranch, etc.

Useful for earth-science
But, from disaster mitigation
purpose, frequency of use of
the system is very small.
Difficult to maintain the system
Long return period of Tsunami
Limited resources, researchers andbudgetPoor experiences of tsunami disasterFigure 2: Comparison between conventional and newly proposed
tsunami warning systems

Weather
Forecasting
Data Use
TsunamiMonitoring

Leisure Condition
Information

Resource
Evaluation
Environmental Monitoring(a) Concept of TWS using Multi-Purpose Buoy(b) Networked Multi-Purpose Buoy System

Figure 3: Concept of proposed tsunami warning system composed of
networked simple multi-purposes observation buoys installed
locally and internationally
2. PROPOSAL OF THE NEW TSUNAMI DISASTER MITIGATIONSYSTEM
My proposed New Tsunami Disaster Mitigation System combines a reliablewarning system and proper evacuation facilities. As mentioned earlier, awarning system such as the one available in the Pacific Ocean Rim region is
not suitable for the Indian Ocean region which has fewer technologicalresources, researchers and experiences of tsunami disasters. For this reason,
I am proposing to use simple multi-purpose observation buoys, which inaddition to serve as a tsunami warning system, would record temperature,

Proposal of a Sustainable Tsunami Disaster Mitigation System for the Indian Ocean Region63December 2007, Dhaka, Bangladesh

current velocity, wave height, moisture, etc. on a daily basis. This
information can be used for weather forecasting, safety assessment, fish
catch prediction, etc. which are useful for the local businesses (Figure 3(a)).
My proposal is to use numerous and simple stations so that the system isredundant and easier/cheaper to sustain. The minimum unit of the proposedsystem would be one or two multi-purpose observation buoys operated andmaintained by hotels/resorts or beach societies in the area. These businesses
will benefit from the daily collected information.
It is expected that many beach societies install the system and join themulti-purpose observation buoy network beyond the administrative orinternational boundaries (Figure 3(b)). In this way, it may be possible togather daily maritime information over a wider area and eventually forecast
a transoceanic tsunami. A system for transferring this information between
associations, domestic and foreign, already exists.
The installation of the proposed buoy system could have additional
advantages. After the December 26, 2004 tsunami, the tourism industry has
suffered greatly not only due to direct impact of the tsunami in theinfrastructure but also due to the unscientific rumors. Visitors that used tocome to resort facilities in the region started avoiding these destinations forfear that a new disaster may occur. In order to recover the tourists’ trust, theinformation collected by the buoy system can be very useful. It is also
known that buoys may become the center of marine ecosystems which could
be an attraction for scuba divers.
Proper evacuation facilities in terms of location, strength and sheltering
capacity are also part of the proposed system. In the region, it is common toobserve temples, churches and shrines located along the coastal line.
Therefore, I am proposing to use similar community centers as evacuation
facilities. This scheme has two main advantages. Because worship centers
are permanently used by the people, their location is well known so that incase an evacuation notice is released, everybody can easily access them.
Additionally, because the people feel strong commitment with thesefacilities, they take active participation in their building and maintenance.

3. ESTABLISHMENT OF THE PROPOSED TSUNAMI DISASTER
MITIGATION SYSTEM
In order to establish the proposed system, several works are needed asshown in Figure 4 and the reconnaissance team, which I headed, carried out
them.
1) Structural damage survey
2) Tsunami numerical simulation
3) Topographical survey4) Questionnaire/Interview survey5) Evacuation numerical simulation

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The first three activities are closely interrelated and their main objective
is to design the configuration and location of evacuation centers. The
structural damage survey is intended to evaluate the tsunami load andcorresponding damage. With this information, the relationship between
tsunami wave load and wave height/velocity can be obtained. With tsunami
numerical simulations using potential earthquake scenarios, it is possible toestimate the wave height and velocity and the tsunami inundation area due
to future tsunami hazards. These data enable us to properly determine
location and structural design criteria for evacuation facilities.

Damage Surveyof Structures

Numerical Tsunami
Simulation using
Potential Faults

Topographical
SurveyTsunami Load

Tsunami Heightand Velocity along
the Coastal line

DigitalElevation
Map

Location Selection
and Design of
Evacuation Facility
Structural Designof Tsunami
Evacuation
Facility

TsunamiInundation
Simulation

Evacuation
Behavior

Questionnaireand Interview
SurveyProposal of
New Tsunami
Warning System

Possibility of
Introductionof theProposed
SystemIntroductionof theProposed
SystemDepth and Velocity

Human Evaluation Simulator in Tsunami Disaster

New Tsunami Disaster Mitigation System Suitable for Indian Ocean Rim Countries

Figure 4: Establishment of the proposed tsunami disaster mitigation system
In order to guaranty that the evacuation centers are fully functional,
their location should be selected so that when the expected tsunami occurs
they will not be washed away. For this purpose, it is indispensable to carryout a topographical survey. Real-time kinematic GPS and laser total stations
are powerful tools for this purpose.
Questionnaire and interview surveys are useful to gather datanecessary for the evacuation behavior simulation. Relationships between
human evacuation velocity and water depth, which are needed for this study,
have already been proposed. The simulation will confirm whether theescape routes and proposed evacuation centers are suitable. Because theproposed tsunami disaster mitigation system heavily relies on theparticipation of regional organizations, the interviews are also helpful toassess the level of acceptance of the system among the people involved.

Proposal of a Sustainable Tsunami Disaster Mitigation System for the Indian Ocean Region65December 2007, Dhaka, Bangladesh

4. CONCLUDING REMARKSThis paper presents a New Tsunami Disaster Mitigation System for the
Indian Ocean Rim region, which combines a reliable warning system andproper evacuation facilities. The warning system consists of multi-purpose
observation buoys operated by local organizations such as hotels and beachassociations. The system is not only used for tsunami warning but also tomonitor temperature, current velocity, wave height, moisture, etc.,
information which can be used on a daily basis for the economic activitiesof the region.
The proposed evacuation facilities are designed taking into
consideration: sheltering capacity, location, and structural strength. Location
is especially important to prevent that the structures are washed away by thetsunami and to guaranty an easy access for the evacuees.
In order to verify the suitability of the proposed system, tsunami andevacuation simulations are recommended. Actually, the research teamheaded by the author has already perform this type of study with someselected areas in Japan and Sri Lanka and proved the system effectiveness.
The strong points of the proposed system are its simplicity, economy anddaily usability, which makes it a sustainable option for the region.

66

New Technologies for Urban Safety of Mega Cities in Asia

Technical Sessions

DIGITAL CHI-CHI CITY ON GOOGLE
EARTH AS POST-EARTHQUAKE RECOVERY DIGITAL ARCHIVEOSAMU MURAO
Graduate School of Systems and Information Science
University of Tsukuba, Japanmurao@risk.tsukuba.ac.jp
ATSUSHI MIYAMOTOTokyo Fire Department, Japan
ABSTRACT
Historical evidences reveal that disasters bring about changes in thedamaged cities across the world through the recovery processes. Recent
geoinformatic technologies enable us to create a virtual representation of acity on a digital model of Earth such as GoogleEarth; these representations
can demonstrate the post-disaster recovery processes. The authors havetracked the post-earthquake recovery process of the Chi-Chi Townshipdamaged during the 1999 Chi-Chi earthquake in Taiwan and constructed avirtual representation of the city based on field surveys to present its
reconstruction conditions as of 2006. The objective of this study is to report
how to construct a representation of a city in cyber space and to discuss thesignificance of recording the recovery process on a digital model of Earth.
This study first describes the background information regarding theexperiment of the trial from the viewpoints of historical changes in therecording media and the significance of the disasters occurring in a city as
critical points in its long-term urban development. It then outlines the six
procedures adopted to create a digitalized virtual representation of the
Chi-Chi Township in addition to the previous researches conducted by theauthors. In the third part, the following procedures are explained in detail:(1) creating a base map using the information obtained from a previous
research conducted by the authors; (2) conducting a field survey to obtain
detailed photographs of building elevation and the number of stories of theobjectives; (3) image processing in order to transform the captured
photographs as rectangular polygons in cyber space; (4) drawing building
outlines using Google Sketch Up, a three-dimensional modeling software;(5) applying the processed images as texture and painting roofs, and (6)Inserting the information related to the reconstruction process. Finally, thisstudy discusses the usage of the abovementioned model to understand thepost-disaster recovery processes and suggests the possibility of using a
digitalized virtual representation of a city on a digital model of Earth as oneof the methods to realize digital archives in the era of the geoinformatics.

67

December 2007, Dhaka, Bangladesh

1. INTRODUCTION
1.1

Present circumstances of spatial information science

The field of spatial information is changing dramatically with thedevelopment in remote sensing technology. In the November 2004 issue of
Nature, Gewin (2004) stated that geotechnology and nanotechnology would
be two of the biggest business fields, the third being biotechnology, in thetwenty-first century. The technological innovation in the field of spatial
information mentioned in this study is forecast to change urban spaces
drastically. In addition, spatial information technology can prove to be an
important tool to record recovery processes.
1.2

Digital archive for urban spaces

For a long time, cities have been formed as a result of the various
changes in their environments. Historical evidence reveals that disasters arelikely to dramatically influence the transformation of cities. For instance,
Chicago has been transformed into a city bristling with skyscrapers since theconflagration in 1871. San Francisco had also attempted to achieve newurban development after the occurrence of the earthquake in 1906 byimplementing the “Phoenix plan.” Thus, based on historical evidence, we
can conclude that disasters and reconstructions tend to be the crucial steps ininfluencing dramatic transformations in cities. In a previous study, theauthors reported on recording disasters and reconstructions and examined amethodology to realize the same (Murao, 2006a). From the viewpoint ofgeotechnological and archival science, it is important to record the processof changes in a city by focusing on the most crucial moments duringhistorical disasters and subsequent reconstructions on a virtual
representation of the city on a digitalized model of the Earth. The authors
have created a networked virtual representation of the Chi-Chi Township,
Taiwan, which was struck by the 1999 Chi-Chi Earthquake, in order torecord the reconstruction conditions on a three-dimensional representationof the city on a digitalized model of Earth accessible freely through
GoogleEarth.

2. PROCEDURE
In order to create the virtual three-dimensional space, the following
processes were carried out:
(1) Creating a base map
First, it was necessary to create a base map of the Chi-Chi Townshipin order to generate a representation of the city. The data from GIS obtainedin the authors’ previous research (Murao et al., 2004) was used for thispurpose.

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New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27(2) Photographing the building facade
Second, a field survey was conducted at the site using the base map.
The actual building conditions including their story heights and roof
conditions were captured roughly. In addition, the exterior walls of thebuildings were also photographed.
(3) Retouching the pictures
The pictures of the exterior walls were arranged according to theblocks and roads in front of the buildings. These were then processed inorder to apply them as textures to the buildings in the three-dimensional
space described later.
(4) Creating three-dimensional space using Google Sketch Up
As the fourth step, the positions were confirmed in order toappropriately lay the base map on GoogleEarth. Then, a three-dimensional
digital representation of the Chi-Chi Township composed of a cluster ofbuildings was generated using Google Sketch Up and a framework of thescenery of the city was reproduced on a computer monitor.
(5) Applying the texture
The photographs acquired in step (3) were applied as textures to theexterior walls of the cluster of buildings created in step (4), and the roofs in
the three-dimensional space were painted with colors similar to those of theactual roofs.
(6) Inserting the information related to the reconstruction process
The information regarding reconstruction obtained in the previous
research was inserted into this three-dimensional representation of the
Chi-Chi Township by using the placemark, one of the functions of
GoogleEarth.

3. CONSTRUCTION OF DIGITAL CHI-CHI TOWNSHIP
3.1

Creating a base map

The digitalized data created by Murao et al. (2004) using GIS wasapplied as the base map (Figure 1) in order to construct a virtual city. Prior
to this, the authors conducted a field design survey based on the IKONOS
satellite images and attempted to define the actual outlines of the buildings(Murao, 2006b). The number of buildings in the target district exceeded
2,000. Then, the data of the shapes of the buildings obtained in this research
was digitalized on GIS and the base map was applied to it. Further, thetarget district was divided into 86 town blocks for further analysis.

Digital Chi-Chi City on Google Earth as Post-Earthquake Recovery Digital Archive69

December 2007, Dhaka, Bangladesh

Figure 1: Base map of the Chi-Chi Township created by GIS(Murao, 2006b)
3.2

Photographing the building façade

By using the base map created in 3.1, the façades of the buildings in
the Chi-Chi Township were photographed in August 2006. Four volunteers
photographed the façades of approximately 1,500 buildings. The following
rules were set to ensure that every photograph captured by the volunteers
would be of the same quality.
Rules for photographing the building façadea) Set the resolution of the camera to 640 × 480 pixelsb) Photograph block by blockc) Photograph the buildings in a town block in a counterclockwiseorder as shown in Figure 2 (a) to enable computers to retouch theimagesd) Photograph one building per shot and, if possible, along the lineof sight perpendicular to the face of the building.
e) If the entire façade of a building cannot be captured in a single
scene, photograph it by dividing the scenery into several(Figure 3)f) Conduct the division from the lower to the upper part and fromthe left to the right side in the above case
Further, the volunteers recorded the form of each roof and the story ofeach building while photographing it (Figure 2(b)).

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How to record the roof form in Chi-Chi
3m①

Roof form④

3

Description②⑤

Roof form③

Description(a) counterclockwise order to photograph(b) recording roof form

Figure 2: Precautions to be followed while photographing the building
façadesFigure 3: one of the examples of the building façade
3.3

Retouching the photographs

The 1,500 digitalized images photographed in process 3.2 wereclassified according to their block and road. In other words, different
directories were created for each block and the images photographed in eachdirection across the roads facing the blocks were stored in folders in these
directories. Even the buildings facing the narrow roads in the blocks were
photographed and classified. These images would be applied as textures on
the façade of the virtual representation of the buildings in the threedimensional model of the city. However, the images were photographed at
the ground level at the site and not along the line of sight perpendicular to
the face of the building. Therefore, the images were processed by using
Adobe Photoshop in order to correct these differences as shown in Figure 4.
After retouching each building image, an elevation image of the cluster ofthe buildings as seen from a road was produced in order to easily apply it to
the digitalized façade. This elevation image is shown in Figure 5.

Digital Chi-Chi City on Google Earth as Post-Earthquake Recovery Digital Archive71

December 2007, Dhaka, Bangladesh

Objectbuilding

camerastreet(a) photograph taken at the site(b) processed image

Figure 4: Correction of the building façade images photographed at thesite

Figure 5: Elevation image of the cluster of the buildings as seen from a
road
3.4

Creating three-dimensional space using Google Sketch Up

Next step is to create an outline of the Chi-Chi Township on acomputer. However, in order to lay the created three-dimensional space on
GoogleEarth (Figure 6), the following steps were necessary: First, thecoordinates of the base map were positioned on GoogleEarth (Figure7).
Second, the outlines of the buildings on the three-dimensional space byusing Google Sketch Up, which is one of the applications of GoogleEarth.
The stories of the buildings and the forms of the roofs were adjusted basedon the information and photographs obtained at the site. Further, thevertical positions of the buildings were adjusted according to the elevations
on GoogleEarth. With the completion of these steps, the scenery of thetarget district with the building outlines was finally generated.

Figure 6: Landscape of Taiwan

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Figure7: Position of the district
3.5

Applying the texture

The last step in creating the three-dimensional space was to apply thephotographs of the building elevations processed in 3.3 as textures to theframes created in process 3.4 (Fig. 8). Because it was difficult to photographthe roofs, the digitalized representations were painted in the threedimensional space by referring to the photographs instead of applying themas textures. Fig. 9 shows the hypothetical representation of the buildings.
3.6

Inserting the information related to the reconstruction process

The information regarding the reconstruction process was inserted into
the virtual representation of the city created in this study by using theplacemark function of GoogleEarth. This information was obtained from theauthors’ previous research (e.g., Murao, 2006b) and can be displayed on
GoogleEarth as described in Table 1.

Figure 8: Application of the elevation photographs as textures to thebuilding frames

Digital Chi-Chi City on Google Earth as Post-Earthquake Recovery Digital Archive73

December 2007, Dhaka, Bangladesh

Figure 9: Example of the buildings in the virtual space with exterior walls
and roofs (before and after applying the texture)
Table 1: Example of the information regarding to the reconstruction
processes that can be displayed on GoogleEarthContents
Information Classification
Location of the facilities
description by Placemark
Explanation of the facilities
text
Image of the reconstruction process
image
Result of the analysis of the reconstruction process graph, table, data, etc.

4. CHI-CHI CITY ON DIGITAL EARTH
This three-dimensional representation of the Chi-Chi Township was referred
to as “Digital Chi-Chi City.” The virtual model of the city in cyber space
represents the Chi-Chi Township as of August 2006. Fig. 10 shows theconstructed digital Chi-Chi Township.
By only uploading the data constructed in this process, it enables
every visitor to enter the Chi-Chi Township freely, gain an experiencesimilar to that of an actual visit through GoogleEarth, and read theinformation regarding the reconstruction process obtained and processed
during the authors’ previous researches. Table 2 lists the information
regarding the reconstruction of the important facilities in the target district.
This information is made available to the visitors by using the placemark
function, as shown in Fig. 11. As research regarding the reconstruction
process progresses, new information will be updated when appropriate andthe range of the contents can be expanded.

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Figure 10: Overview of the Digital Chi-Chi City
Table 2: Information regarding the reconstruction of the important facilities
in the target district
ID

Facilities

01 Chi-Chi Sightseeing Center
02 He-Ping National Primary School
03 Chi-Chi Government Office
04 Chi-Chi Health Center
05 The First Market
06 Chi-Chi Station
07 Railroad Musium
08 Chi-Chi Resort Center
09 Chi-Chi Public Swimming Pool
10 Parking Lot
11 Chi-Chi Police Station
12 Chi-Chi Nationarl Junior High School
13 Chi-Chi Nationarl Primary School
14 Farmer Bank
15 Wu-Chang Temple
16 Guang-Sheng Temple
17 Temporary Housing (I) (138+20)
18 Temporary Housing (II) (72)19 Temporary Housing (III) (23)20 Permanent Housing constructed by Chi-Chi Governmen

Structure (The Numberof Stories)(Before theParking Lot
RC (2F)RC (4F)RC (2F)RC (3F)

2001/12/1
1999/9/26
2000/4/22
2003/4/4
2002/10/30

Date ofConstruction
Completion
2006/8/31 Unfinished2000/4/27
2002/10/15
2004/summer
2004/summer

2000/4/21
2002/1/2
2000/12/27
2000/4/9
1997/7/9
2002/8/10
2000/6/1
2000/6/1
1999/11/1
2000/7/1
1999/10/20
1999/9/26
1999/9/26
2000/8/1

2000/7/24
2002/3/8
2001/12/31
2002/11/22
2001/1/17
2004/summer
2000/12/1
2001/3/1
2001/12/19
Preserved
2003/8/1
2000/1/28
1999/10/13
1999/10/13
2002/3/1

Date ofConstruction Start

Wooden (1F)
Wooden (1F)RC (5F)RC (B2F)
RC (3F)RC (2F)RC (2F)RC (3F)RC (3F)
Wooden (1F)－－－－

GIS-ID
S-14001
S-61001
B-18022B-41044
B-09045
B-07027
B-07023
B-73001
S-71001
S-19001
B-18***
S-80001
S-19001
B-06010
S-74001
S-40001
S-66001
S-75001
S-86001

Figure 11: Example of displaying the information regarding thereconstruction process using the placemark function

Digital Chi-Chi City on Google Earth as Post-Earthquake Recovery Digital Archive75

December 2007, Dhaka, Bangladesh

5. CONCLUSION
In this study, the authors report on the Digital Chi-Chi City constructed torecord the reconstruction conditions of the damaged area and allow visitors
to freely access a three-dimensional representation of the city on a digitalmodel of Earth. In order to construct the Digital Chi-Chi City, the following
processes were undertaken:
1. Creating a base map
2. Photographing the building façade
3. Processing the photographs
4. Creating a three-dimensional space using Google Sketch Up
5. Applying textures
6. Inserting the information regarding the reconstruction processThis Digital Chi-Chi City enables visitors from around the world tofreely access the city on a digital model of Earth and gain an experiencesimilar to that of actually visiting the Chi-Chi Township.
The characteristics and significance of the Digital Chi-Chi City are as
follows;
1) It is a three-dimensional representation of actual city on a digitalmodel of Earth created using the freely accessible platform of
GoogleEarth.
2) For a city with a long history, the process of reconstruction
following a disaster brings about dramatic changes in the city andbecomes a crucial point in its history. The digital Chi-Chi City is a
reproduction of the actual city in three-dimensional space for thisgeoinformatics era.
3) The procedure for inserting the conditions of the recovery process
into the representation in the digital model of Earth exemplifies oneof the possibilities wherein digital archives can be used to record
reconstruction processes.
The authors will update the information regarding the reconstruction
process when appropriate while continuing their research on the Chi-Chi
Township.

ACKNOWLEDGEMENTS
This work was supported by the Japan Society for the Promotion of Science(JSPS) through the Grants-in-Aid for Scientific Research No. 16401022“Architecture of Reconstruction Process of Chi-Chi Area (Taiwan) andArchives related to Urban Reconstruction in the World” and Grant-in-Aid
for Exploratory Research No. 18656179 “Construction of Digital Archives
for Urban Recovery using Satellite Images”. The authors would like toacknowledge Yayoi Mitsuda; the translator of the Chi-Chi research project;
Yasuhisa Fujita and Kenichi Saito from Digital Earth Corporation who
advised lots of things; Hideaki Nakazato and Tomomi Hayashi from76

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University of Tsukuba as volunteers, and the officers and residents of the
Chi-Chi Township.

REFERENCES
Gewin, V., 2004. Mapping Opportunities. Nature, No. 427, 376-377.
Murao, O., Ichiko, T., and Nakabayashi, I., 2004. Evaluation of Building
Reconstruction Process in Chi-Chi Area based on a GIS-Database after
the 1999 Chi-Chi Earthquake, Taiwan. 13th World Conference on
Earthquake Engineering (CD-ROM), No.174, Vancouver, Canada.
Murao, O., 2006a. Memories and succession for constructing archives
describing the reconstruction processes of a city as archival science inan era of town planning during the reconstruction processes after adisaster with strategies for the next generation. Zoukei Shinsho,
Kenchiku-Shiryo Kenkyusha, 62-65 (in Japanese).
Murao, O., 2006b. Structure of Post-earthquake Recovery Process after the1999 Chi-Chi Earthquake -A Case Study of Chi-Chi. Proceedings of theInternational Symposium on City Planning, Taipei, Taiwan, 164175makes it a sustainable option for the region.

Digital Chi-Chi City on Google Earth as Post-Earthquake Recovery Digital Archive77

December 2007, Dhaka, Bangladesh

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New Technologies for Urban Safety of Mega Cities in Asia

VISUAL SCREENING METHODS FOR EAR
THQUAKE VULNERABILITY ASSESSMENT
A. B. AFIFA IMTIAZ
Dept. of Civil Engineering, Bangladesh University of Engineering andTechnology (BUET), Bangladesh
afifaimt@gmail.com
MAHFUZA SHAMIM
Dept. of Civil Engineering, BUET, Bangladesh
mly_054@yahoo.com
ASHUTOSH SUTRA DHAR
Dept. of Civil Engineering, BUET, Bangladesh
ashutoshdhar@ce.buet.ac.bd
MEHEDI AHMED ANSARY
Dept. of Civil Engineering, BUET, Bangladesh
ansary@ce.buet.ac.bd
MOHAMMED JOBAIR, MD. ZAKARIA AHMED
Dept. of Civil Engineering, BUET, Bangladesh
ABSTRACT
Several pre-earthquake screening methods have been developed
recently for rapid evaluation of vulnerability profiles of the existing building
stocks. The objective of these methods is to identify, make inventory andrank all high-risk buildings in a specified region so that a strategy ofpriority based interventions to buildings can be formed. The Federal
Emergency Management Agency (FEMA) of the United States of America
has developed a method of potential seismic hazards of buildings based on
rapid visual screening. The rapid visual screening method, widely known as
RVS method, has generally been used for assessment of seismic
vulnerability of structures. This screening methodology is encapsulated in a
one page form, which combines a description of a building, its layout andoccupancy, and a rapid structural evaluation related to its seismic hazard.
Another approach of rapid visual screening was employed for assessment ofseismic vulnerability of structure in Turkey, which was developed after the1999 earthquake in the cities of Kocaeli and Düzcec in Turkey. The method
uses two level seismic assessment where at level 1, a street survey is usedregarding a structural form and the ground condition while more rigorous
information of the buildings are used at level 2 of the assessment. Both ofthe methods have been used in this research for seismic vulnerability
assessment of buildings in Cox’s Bazar district in Bangladesh. The study
reveals that the method proposed in FEMA is much more conservative
relative to method used in Turkey. The vulnerability score estimated using
the FEMA method was less than the “cut off” score for almost all thebuildings while the score estimated using the Turkish method was much

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above the “cut off’ score. This paper critically examines the two methods
with reference to the seismic assessment of structures in Cox’s Bazar andidentifies the key parameters contributing to the vulnerability assessment.

1. INTRODUCTION
Vulnerability Analysis of building stocks in a region is a very difficult andtime-consuming process. Step by step identification of buildings at mostseismic risk can make the whole procedure comparatively simpler. First stepin this process can be quickly screening of buildings to determine if
evaluation is required. This procedure requires only visual inspection andlimited data collection. The visual screening method has been used in thisresearch for 250 Cyclone Shelters and 52 General Buildings of Cox’s Bazar
District in Bangladesh. The study included two different visual screening
methods, i.e. FEMA-RVS and Turkish Simple Survey Procedure. FEMA
Rapid Visual Screening (RVS) of buildings for potential seismic hazards
originated in 1988, with the publication of the FEMA 154 Report. It is a“sidewalk survey” approach that enabled users to classify surveyedbuildings into two categories: those acceptable as to risk to life safety or
those that may be seismically hazardous and should be evaluated in moredetail by a design professional experienced in seismic design. The Turkish
Simple Survey procedure is a two level risk assessment procedure which has
been proposed on the basis of statistical correlations obtained by employing
a database of 477 damaged buildings surveyed after the 1999 Düzce
earthquake (Sucuoglu and Yazgan, 2003). The first level incorporates
recording of building parameters from the street side and in the second level,
these are extended by structural parameters measured by entering into theground story.

2. METHODS REVIEW
2.1

FEMA Rapid Visual Screening

The Data Collection Form of RVS includes space for documenting
building identification information, including its use and size, a photographof the building, sketches, and documentation of pertinent data related toseismic performance, including the development of a numeric seismic
hazard score. Basic Structural Hazard Scores based on Lateral Force
Resisting System for various building types are provided on the form, andthe screener circles the appropriate one. The screener modifies the Basic
Structural Hazard Score by identifying and circling Score Modifiers related
to observed performance attributes, by adding (or subtracting) them a final
Structural Score, ‘S’ is obtained. The scoring system of RVS is shown in
Figure 1.
The score below which a structure is assumed to require further
investigation is termed as “cut-off” score. The value of “cut off” score andchoice of RVS form depends on the seismic zonation of the area. It is80

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suggested that buildings having an S score less than the “cut-off” score
should be investigated by an experienced seismic design professional
experienced in seismic design. If the obtained “final score” is greater thanthe “cut-off” score the building should perform well in a seismic event. A
score of 2 is used in this study as a “cut-off” score, based on high seismic
zone.

Figure 1: Sample RVS Scoring Form (FEMA-154, 2002)
2.2

Turkish Simple Survey Procedure

This is a two level seismic risk assessment procedure based on several
building parameters that can be easily observed or measured during asystematic survey. The basic scoring for both the levels are based on the
Height of the building (number of stories) and Local Soil Conditions where
three intensity zones are specified in terms of associated PGV (Peak Ground
Velocity) ranges. Once the vulnerability parameters of a building are
obtained from two-level surveys and its location is determined, the seismic
performance and vulnerability scores are calculated as defined in Figure 2.
The final seismic Performance Score is obtained by using Equation (1). A“cut-off” performance score of 50 has been suggested for both survey levels.
PS = (Initial Score) - ∑ (Vulnerability Parameter) X (Vulnerability Score)(1)

The first level is a street survey procedure and involves theobservation of the parameters, the number of stories above ground, presenceof a soft story, presence of heavy overhang, apparent building quality, andpresence of a short column.
In the second level the parameters of first level are confirmed or
modified through closer observations. Then a sketch of the framing plan at
the ground story is made and the dimensions of columns, concrete andmasonry walls are measured. The added parameters in this stage arepounding between adjacent buildings, topography effect, plan irregularity,
redundancy, and strength index. The consistency in distribution of lateralloads to frame members is judged by redundancy and the strength index
figures out the influence of size of the vertical members of the building,

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material strength, frame geometry etc. on the lateral strength of the building.
The results of the Level - II procedure can be used to determine the potential
status of the selected buildings, and to further short-list the buildings
requiring detailed vulnerability assessment.

Figure2: Tables and General Equation of Turkish Procedure(Sucuoglu and Yazgan, 2003)

3. ASSESSMENT OF BUILDINGS IN COX’S BAZAR
3.1

Buildings Analyzed

From the structural consideration, only Reinforced Concrete with
Unreinforced Masonry Infill Wall (URM INF) of burnt brick buildings of
Cox’s Bazar area have been selected for seismic vulnerability assessment.
The buildings to be surveyed have been divided into two particular
categories, one is the Cyclone Shelters and the other one is General
Buildings used for residential or commercial purposes.
3.1.1 Cyclone Shelters
The cyclone shelters are the structures developed under theMultipurpose Cyclone Shelter Program by the Government of Bangladesh
in 1993 after the great cyclone of 1991. There are 455 cyclone shelters in
different places of the district (Uddin and Yasmin, 2005), which serve in82

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sheltering people during the cyclones and are used as schools or foodstorage at other times. Most of the shelters of the area were built after the
1991 cyclone with the help of Donor countries and agencies. The existing
shelters are usually two to three storied keeping the Ground Floor totally
open. On an average every shelter is capable of accommodating 1000 to
1200 people at disaster period.
3.1.2 General Buildings
General Buildings include the buildings used for residential orcommercial purposes. They house a significant number of people and can beused as Shelters during Disaster where Cyclone Shelters are insufficient tohouse the inhabitants. Again analyzing these buildings enables theassessment of general construction practices of the area and thus thevulnerability due to seismic activity. It can also act as a guide for suggesting
any modifications or improvements in design and construction works tomake the buildings earthquake resistant.
3.2 Assessment by FEMA Method
A total number of 250 Cyclone Shelters and 52 General Buildings
have been analyzed using Rapid Visual Screening (RVS) method.
Considering Cox’s bazar as a high Seismic Risk zone, the cut off value wasdetermined as 2. The results show that no score for cyclone shelter and otherbuildings was found to touch the cut off value according to FEMA method
and all of them require further detailed analysis for vulnerability todetermine the level of actual risk. Figure 3 shows summary of the RVS
score for different buildings. In fact the basic score for RC building in
FEMA-RVS is only 1.6 (less than the cut off), which becomes smaller after
being modified by the negative parameters. This is one of the reasons for the
FEMA RVS score to be less. The parameters contributing the scoring
system are mainly, the height, irregularities of the buildings and type of thesoil underneath. As there is no real practice of following national designcode for construction works in Bangladesh, the parameters Pre Code andPost Benchmark remained inapplicable in the scoring. On a general view,
the soil type of Cox’s Bazar has been considered as Stiff, so this modifier
also remains constant in the whole process.

(a) Building Shapes Variation
for Cyclone Shelters(b) RVS Score Variation
for Cyclone Shelters(c) RVS Score Variation
for General Buildings

Figure 3: RVS Score Variations for the Surveyed Buildings

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Figure 4: Three Distinctive Shapes of Cyclone Shelters responsible
for respective Variations in Scores
In case of Cyclone Shelters, all the buildings in the area are below 4storied. Thus the irregularities of the buildings only contribute to the scorevariation. The Cyclone Shelters have some common forms in shape. Most ofthem are of regular shapes (square, rectangular, few circular), some are “V”shaped and the rest of the buildings have some irregularities vertically or inplan (as shown in Figure 3-a and Figure 4). Almost all the shelters haveopen ground floors which indicate the existence of soft/weak story effect,hence imposing vertical irregularity which is the major factor contributing
in lowering the scores significantly. It has been observed that among thebuildings without soft story, those having no irregularities (regular shape)score 1.2 whereas the “V”-shaped (only plan irregularity) ones score 0.7.
The buildings having soft story effect with vertical irregularities or both(including plan irregularity) score ≤0.4 (Figure 3-b).
Almost similar picture is reflected in case of General Buildings(Figure 3-c). A new score level, 1.4, has been added here. The Mid-risebuildings which have stories greater than 3, got a positive score
modification of 0.2 and thus the final score uplifted a bit. Another point to
be noticed here that plan irregularity is observed less in General buildings
compared to the Shelters. Thus relatively fewer buildings showed in scorelevel 0.7 or less.
It is also possible to interpret the RVS scores, based on the presence oftype of Performance Modifiers, into the probable damage due to an
earthquake according to The European Macroseismic Scale (EMS). EMS isthe basis for evaluation of seismic intensity in European countries. Most
recently updated in 1998, the scale is referred to as EMS 98, which denotes
how strongly an earthquake affects a specific place. Based on the principlethat the way in which a building deforms under earthquake loading depends
on the building type, EMS has categorized intensity of building damages indifferent categories for different structure types. The RVS scores for RC(URM INF) buildings of a High Seismic Zone obtained from the analysis
have been grouped on the basis of the existence of the Performance
Modifier Type. The consequent damage expected due to the presence of theparticular modifiers has been implicated in terms of Probable Damage
Classification and then interpreted as the Damage Description following
EMS definitions. Table-1 shows this probable damage classification basedon FEMA RVS Scores. However, it should also be noted that the actual84

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damage will depend on a number of factors that are not included in the RVS
procedure. As a result, the implications should only be used as indicative todetermine the necessity of carrying out simplified vulnerability assessmentof the buildings. These results can also be used to determine the necessity ofretrofitting buildings where more comprehensive vulnerability assessment
may not be feasible.
Table 1: Probable Damage implications from RVS for RC (URM INF)
buildings in High Seismic ZoneRVS Score
1.2<S<2

0.7<S<1.2

0.4<S<0.7

S≤0.4

3.3

Probable
DamageVery HighProbability ofGrade 1
DamageHigh
Probability ofGrade 2
Damage andVery HighProbability ofGrade 1
DamageHigh
Probability ofGrade 3
Damage andVery HighProbability ofGrade 2
DamageHigh
Probability ofGrade 4 toGrade 5
Damage andVery HighProbability ofGrade 3
DamageDamage Classifications for Reinforced Concrete
Buildings (Following EMS)
Grade 1: Low Damage (No major structural
damage, susceptible to more non-structural
damages)
Probability of fine cracks in plaster over frame
members or in walls at the base or in partitions
and infill
Grade 2: Moderate damage (Slight structural
damage, moderate non-structural damage)
Cracks in columns and beams of frames and in
structural walls. Cracks in partition and infill
walls; fall of brittle cladding and plaster. Fallingmortar from the joints of wall panels.

Grade 3: Substantial to Heavy Damage(Moderate structural damage, heavy nonstructural damage)
Cracks in columns and beam-column joints offrames at the base and at joints of coupled walls.
Spalling of concrete cover, buckling of reinforced
bars. Large cracks in partition and infill walls,
failure of individual infill panels.
Grade 4: Very Heavy Damage (Heavy structural
damage, very heavy non-structural damage)
Large cracks in structural elements withcompression failure of concrete and fracture of
rebars; bond failure of beam reinforcing bars;
tilting of columns. Collapse of a few columns or ofa single upper floor
Grade 5: Destruction (Very heavy structural
damage)Collapse of ground floor parts (e.g. wings) of thebuilding.

Assessment by Turkish Method (Level – I)

All the Shelters and the General Buildings, specified previously, havebeen analyzed by Turkish Method (Level – I) of visual screening. Here, theassessment has been performed considering the soil zonation of Cox’s Bazar
in Zone-1 (60<PGV<80). In this method much more variation in final scores

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has been observed as not only the basic score but also the influences ofvulnerability parameters are very much dependent on the height of thebuilding. In fact the positive or negative score modifications due tovulnerability parameters are weighted multiplications based on their
existance and number of stories of the buildings. As a result the scorebecomes high for low rise buildings in spite of presence of negatively
influential vulnerability parameters. Due to these dependant variations, it iscomparatively tougher task here to classify the damage probabilities withminute specifications, as that of RVS-FEMA method, only from final scores.
Rather it is easier to indicate an overall view on safety of the building
comparing the final score with the cut off value and observing their relative
difference.
Figure 5-a reflects that no buildings from Cyclone Shelters and veryfew (5%) from General Buildings scored less than 50 (the “cut-off” score),that means according to the Level – I survey. Thus all these buildings do notneed further detailing on vulnerability assessment, or they can be termed assafe. When the performance scores of the buildings have been placed
against building story, it was found that other than few 3 storied ones all theShelters scored above 70 (Figure 5-b) and all the General Buildings scoring
less than 50 (Figure 5-c) were midrise (4 to 6 storied). The observed
general trend is that the taller the buildings the higher the presence ofnegative parameters and thus the lower becomes the scores.

(a) Turkish (Level-I) Score
Variation(b) PS vs. Story (Level-I)
for Cyclone Shelters(c) PS vs. Story (Level-I) for
General Buildings

Figure 5: Turkish (Level-I) Scoring Variations for the Surveyed Buildings
3.4

Assessment by Turkish Method (Level – II)Though the buildings identified as unsafe or lower scored compared to
the “cut-off” value in Level-I were supposed to be judged by Level-IIprocedure, in this investigation all the general buildings were analyzed again
in the Level-II to see the difference of score variations between these two
methods. No Cyclone Shelter scored less than the “cut-off” and was notconsidered here for this re-evaluation process. Figure 6 compares the scoresof buildings according to Level-I and Level-II survey. From the results
represented in Figure 6, it can be concluded that the buildings scoring morethan or around 50 in Level-I behaved better in Level-II scoring higher. The

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buildings failed to exceed the “cut-off” in Level-II are those which hadscores much lower in the former phase.

Figure 6: Turkish Scoring (Level-I & Level-II)
for the General Buildings
4. COMPARATIVE REVIEW OF THE METHODS
A comparative review of the two RVS methods has been presented herewith regards to the aspects considered in each of the methods. An attention
was paid on applicability of the methods in Bangladesh. Figure 7 shows thecomparative scoring picture of these two methods for a building.

Figure 7: Scoring Systems of RVS and Turkish Method
The FEMA-154 RVS considers 15 structure-types (timber frame, steel
frame, RC, masonry) whereas the Turkish Procedure can only be used for
RC buildings which makes constraints its use for wider aspects in countries
like Bangladesh where unreinforced structures occupy a major portion of
the existing construction practices. Data collection form in FEMA RVS
includes building information (use, size etc), photograph, sketches, pertinent
data related to seismic performance – which help in developing inventories
of building. On the other hand Turkish Data collection form includes few
simple structural and geotechnical parameters which might not be sufficientfor providing any support idea to be decisive in case of any confusion about
the structure. FEMA has the provision of considering benchmark years ofadopting and improving seismic codes. Turkish method evaluates themultistoried RC buildings which do not conform to the requirements ofVisual Screening Methods For Earthquake Vulnerability Assessment

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modern seismic design and construction codes. Thus, the Turkish method
may be suitable for the countries like Bangladesh where seismic designcodes are of no practical use. A broad definition of Vertical Irregularity is
included in FEMA method such as soft/weak story, geometric irregularities,
mass irregularities, and steps in elevation /inclined walls/discontinuities inload path / hillside site. However, the Turkish method evaluates only softstory and topography effects while it is clear from past experience thatstructural irregularities can be significant in the performance of a building
during an earthquake
Basic Scores in FEMA-RVS are based on average expected groundshaking levels for the seismicity region and the lateral force resisting systemof structure where soil condition acts as a negative performance modifier
and higher number of stories in a building acts as a positive modifier on thescoring system. No structural characteristics are judged and Site aspects
such as potential pounding between buildings, apparent quality are noted
and quantified in this method. Conversely in Turkish method Basic Scores
are based on the intensity of ground motion (Zoning is represented by PGV
range of the locality) and the variation of building stories. This method
considers buildings up to 7 stories where the increasing number of stories
reduces the performance score by influencing almost all other Vulnerability
Parameters negatively. Pounding effects and apparent quality of the building
as well as the structural characteristics, Redundancy and Stiffness Index, act
as weighted Vulnerability Parameters in the scoring system of Turkish
screening. These contradictions have been reflected prominently in thescores where no buildings found to be safe in RVS method and almost all ofthem were configured as satisfactory in Turkish.
The advantages of FEMA-RVS are its simplicity, relatively low costto gather the required field data, provision of effective estimates fordetermining future emergency planning or mitigation, effectiveness of theprocess for detailed evaluations. In spite of the benefits this procedure hassome shortcomings. It provides generalized results only in terms ofstructural score and without any explanation or specification for particularbuilding type, only incorporates Pass/Fail results (decision of detailed
evaluation required or not) rather than being explanatory on the scores,
based on three pre-determined seismicity regions (lack of refinement), does
not incorporate seismic event when determining the final “structural score”
and over all it is a very conservative approach. It has another disadvantagethat it may be too conservative and the assigned score may indicate that thebuilding presents a greater risk than it actually does. Turkish procedure isalso simple from all aspects but from the experience of survey it isnoticeable that the structural measurements in Level-II, which act as very
important vulnerability features, has made the method somewhat tougher as
residents of the buildings do not co-operate the screeners and restrict theirentry to the ground floor. Again, though this method considers moreparameters than RVS, it becomes also conservative by predetermining thestructural configuration to RC buildings and number of stories limiting up to
7 only.

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5. CONCLUSIONSThe evaluation of two different methods in this paper has enabled thecritical examination of the advantages and shortcomings of the methods. It
appears that the scores obtained from the two methods indicate
contradictory conclusions for the buildings investigated. Aspects consideredin the RVS method provided conservative results. Both of the methods have
limitations in terms of incorporating the parameters relevant for Bangladesh
and many other countries. Considering these differences it might be possible
to conduct a further study to configure suitable attributes for proposing asound risk assessment technique focused particularly on the design andconstruction practices of the country. The study reveals that fine-tuning of
the significantly contributing technical aspects of these procedures can leadto the development of an ideal Rapid Visual Screening Procedure which
would provide more reliable assessment of the seismic vulnerability of thebuildings, and form the basis for determining need for more complex
vulnerability assessment.
ACKNOWLEDGEMENT
The authors acknowledge the funding of this research project by United
Nation Office for Project Service (UNOPS) through Comprehensive
Disaster Management Program (CDMP) of the Ministry of Disaster Relief
and Rehabilitation of Bangladesh Government. The authors are also
thankful to Mr. Mohammed Jobair and other Research Assistants of the
project who helped in analyzing the data.

REFERENCES
FEMA154, (2002). Rapid Visual Screening of Building for Potential
Seismic Hazards: A Hand Book
European Macroseismic Scale (1998). Macroseismic Intensity Scale.
Classifications used in the European Macroseismic Scale (EMS).
European Seismological Commission, Editor G. Grünthal,
LUXEMBOURG 1998
Sucuoglu, H. And Yazgan, U. (2003). Simple Survey Procedures for
Seismic Risk Assessment In Urban Building Stocks. Seismic
Assessment and Rehabilitation of Existing Buildings, 97-118, NATO
Science Series, IV/29, Editors: S.T. Wasti and G. Ozcebe, Kluwer
Uddin, A. M. K. and Yasmin, A. (2005). District Information-Cox’s Bazar.
Water Resource Ministry, Water Resource Planning Organization,
People’s Republic of Bangladesh Government.

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NUMERICAL AND EXPERIMENTAL STUDYOF STRUCTURES WITH SOFT STORIESHIMADREE ROY
Bangladesh University of Engineering and Technology, Dhaka, Bangladesh
liju_113/08@yahoo.com
IFTEKHAR ANAMThe University of Asia Pacific, Dhaka, Bangladesh
ifteanam@accesstel.net
ABSTRACTSoft stories are one of the prime reasons of structural failure during
earthquakes. However, very little attention is paid to this serious design
deficiency by architects or engineers in Bangladesh. This paper presents
results of numerical and experimental works performed on the seismic
response of structural models with soft stories. The experimental facilities
used for this purpose includes a small shake table capable of generating
defined earthquake motion, using an indigenous and inexpensive approachfrom the combination of mechanical and electrical equipments. It is
probably the first such work reported in Bangladesh and this concept can beused for developing larger shake tables, the cost of which would otherwise
be prohibitive. The structural model used for the experiments is a 3-storied
structure made of springs (as columns) and timber plates (as floors). Floor
vibrations are recorded with time using mechanical devices. The dataacquisition system is found to be very accurate as the recorded groundmotion matches very well with the target ground motion data. Several
experimental scenarios are created by changing the structural mass andstiffness at different floors and subjecting the structural model to scaled El
Centro ground vibrations of different time durations. The experimental
results match very well with the numerical predictions from computer
program using dynamic analysis incorporating the nonlinear loaddeflection relationship of the springs.

1. INTRODUCTION
The threat of earthquake in Bangladesh is a widely accepted reality now,
particularly after devastating effects of earthquakes in almost all theneighboring countries (e.g., India, Pakistan, Sri Lanka, Afghanistan) andmany others within South-east Asia. In the backdrop of such devastating
earthquakes, there is growing need for serious theoretical and experimental
works on seismic behavior of building structures and control of structural
vibration under strong ground shaking.
The lack of testing facility on earthquake vibration is of particularconcern due to the recent awareness or alarm of seismic vulnerability of theengineering structures in Bangladesh. Although some useful theoretical91

December 2007, Dhaka, Bangladesh

works on these topics have been performed mainly at academic institutions,very few of these works have been supported by corresponding
experimental verifications. In fact no work has yet been reported that had
simulated real earthquake ground motion data.
Assessment of structural damage patterns has diagnosed soft stories inbuilding frames caused by discontinuities of the story stiffness as one of theprime reasons of structural failure. However, very little attention is paid tothis serious design deficiency by architects or engineers in Bangladesh. Infact due to the quick growth of high-rise buildings and lack of parking
facilities in urban areas, most newly built buildings are designed with open
ground floors supporting stories with masonry infills, and as a result thisdeficiency is even more widespread in building structures now than everbefore. Due to lack of knowledge of the mechanical properties of brickmasonry, the structural analysis of a frame under lateral load and vibration
is often performed by taking the stiffness of RC columns and beams into
consideration, but the stiffness of brick infill is almost never considered inthese calculations.
In order to better understand the structural behavior of RC frames
subjected to lateral loads or ground motions, it is necessary to understandthe characteristics of brick masonry infills. Nonlinear dynamic analysis isoften performed for the frames replacing the brickwalls by an ‘Equivalent
Diagonal Strut’ proposed by Saneinejad & Hobbs (1995) and modified by
Madan et al. (1997). Although the work on the in-plane behavior of infills is
comparatively new in Bangladesh (Hossain, 1997, Azam & Amanat, 2005,
Anam & Azam, 2006), it has been extensively studied over the last several
decades (e.g., Omote et al., 1977, Engelkirk and Hart, 1984, Papia, 1998,
Asteris, 2003) in attempts to develop a rational approach for design of suchframes, many of which demonstrated the poor performance of structureswith soft stories.

2. CONTEXT AND OBJECTIVES
Experimental verification of nonlinear dynamic analyses was initiatedlocally at The University of Asia Pacific (UAP). Results of the initial tests
and numerical verification were reported by Manju (2004) and Manju et al.
(2005). Since these works concentrated on sinusoidal ground motions only,
the structural responses depended very strongly on the frequency of the
motions (i.e., due to resonance) and could not provide a rational assessmentof structural behavior during real earthquakes or assess measures ofstructural control or improvement.
The main objective of this work is to report development of theexperimental facilities used for this purpose (Roy, 2007), including a small
shake table capable of generating defined earthquake motion (scaled El
Centro earthquake) using an indigenous and inexpensive approach. It is thefirst such work reported in Bangladesh and this concept can be used for92

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developing larger shake tables, the cost of which would otherwise beprohibitive. The importance of the work can be assessed in this context.
Moreover, since the effect of soft stories on the structural behavior
during earthquakes is seldom considered seriously in Bangladesh, theexperimental works also simulate structural models with soft stories. Theirstructural properties are modified easily by changing the stiffness and mass
for time varying ground vibration here. Numerical results of the structural
motions are compared with measured experimental results for simple
building models, particularly observing the effects of soft stories.

3. NUMERICAL FORMULATIONThe numerical formulation for the analysis of the model structure is basedon the concepts of nonlinear structural dynamics (Chopra, 1995). The mass,
damping and stiffness matrices can be generalized for a multi-degree-offreedom (MDOF) system, so that the equations of motion of a system
subjected to ground acceleration ag can be written in the general form
M d2ur/dt2 + C dur/dt + K ur = − M r ag
(1)
where the bold capital letters (M, C, K) represent the mass, damping andstiffness matrices, the bold small letters (d2u/dt2, du/dt and u) represent theacceleration, velocity and displacement vectors and r = {1;
1;………………..1}T is a displacement transformation vector. Equation (1)is solved numerically to obtain the variation of displacement vector u withtime. The Constant Average Acceleration (CAA) method is used here fornumerical time-step integration to solve the dynamic equations of motion.
One aspect in implementing the time-step integration method
mentioned above is the dependence of the stiffness matrix K on the relative
floor deformations. As the springs in the structural model are not linearly
elastic, the K matrix is not a constant and needs to be updated at each time
step depending on the value of the displacement vector u i+1. As such,
equation (1) can be rewritten as(2)(Keff) i+1 ui+1 = − M r ag i+1 + C (veff)i + M (aeff)i
where the bold small letters a, v and u indicate acceleration, velocity anddisplacement vectors respectively. The nonlinear equations need to besolved by an iterative method. The direct iteration method, also known as
Picard method, has been used here for the nonlinear dynamic analyses(Reddy, 1993). A computer program has been developed in order toimplement the numerical method described. It is a nonlinear dynamic
analysis program carried out in the time domain.

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4. EXPERIMENTAL SETUP
4.1

Structural model and ground motion arrangement

The structural model used in the experimental works is a three-storiedmodel structure in addition to the ground floor and is about 60 cm high.
Each floor is composed of a (60 cm × 60 cm) timber plate (modeled as floorslabs) and nine helical springs (for columns). They are assumed to provide
the entire mass and stiffness respectively of the system.
The ground floor is supported on four-legged stand by means of fourrollers on the corner. The rollers are attached to the stand. On the top of theground floor there are three other floors each supported by springs coiled to
the floor below. There are provisions for attaching extra weight on eachfloor. Without any extra weight, each floor weighs about 2 kg.
There is a 1.5 m long plate with the scaled El Centro earthquake data
(marked as shown in Figure 1). This plate data is achieved by the original El
Centro earthquake data divided by a scaling factor to ensure that it isaccommodated within the shake table and allows the ground floor to vibrate
freely. The base floor of the model is connected to the plate by a 5 cm
connector and attached by screw in the middle of the plate, which
effectively simulates the ground motion for the structural model. The otherfloors of the structure vibrate due to this ground motion.
A rotating shaft is fixed with a motor and rotates under the plate to
generate the forward motion of the plate. The motor has a capacity of 1750
rpm, and its speed can be modified by a regulator. Thus the original El
Centro data (time duration of 40 seconds) was run at three time durations;
i.e., 15, 20 and 25 sec. The movement of the plate along the rotating shaft isshown in Figure 2.
4.2

Measurement of displacements

The arrangement used in this work to measure the dynamic structural
includes a paper moving over a movable roller, the paper being able to slide
over the roller at a certain speed, controlled by an arrangement of pulleysystem. Once the paper starts rolling it can record the motions of any floor
as it vibrates with time, using a marker set at the floor level. The main
device is about 1.8 m high and the arrangement for recording thedisplacement can be placed anywhere along its height.
4.3

Creating soft or weak story

The structural models have some arrangements to make any story softor weak. To do that, the number of helical springs for a floor (originally it isnine) is reduced. In several simulations used in this work, only five springs
are used in the ground floor to make this storey soft compared to the otherfloors of the structural model. A similar procedure is used to make a soft

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first floor in some experiments. These arrangements are shown in Figures
3(a) and 3(b).

Figure 1: El Centro Earthquake plate(Marked)Figure 2: El Centro Earthquake plate
moving along rotating shaft

Figure 3: Arrangement with (a) Soft first story, (b) Soft second story
4.4

Properties of 3-storied structural model

The mechanical properties used for the 3-storied structural model are
based on the work by Manju (2004). The load vs. deformation data showsthat the floor springs have nonlinear elastic behavior with similar properties
in lateral deflection on either side. The damping of each floor is determinedby matching results of the free decay test of the top floor, which gave thedamping ratio of each floor to be about 17%. This comparatively highdamping ratio indicates significant friction within various components of thestructural model.

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5. RESULTS FROM NUMERICAL ANALYSIS AND EXPERIMENT
5.1

Laboratory simulation of scaled El Centro ground motion

One of the first objectives of the present work was to generate apredefined earthquake ground motion in the laboratory set up. As mentioned
earlier, the El Centro ground motion scaled down (to a maximum groundmotion amplitude of 3.5 cm) to allow the structural model to vibrate freely
was intended to be generated here within time durations of 15, 20 and 25
seconds. Figure 4(a) shows the target ground motions while Figure 4(b) is
the motion actually simulated in the laboratory in 15 seconds.

Ground Displacement (cm)

6
4
2
0
-2
-4
-6
0

3

6

9

12

15

0

3

Time (sec)

6

9

12

15

Time (sec)Figure 4: (a) Scaled El Cento ground motion, (b) Recorded motion in 15 seconds

The comparison between Figure 4(a) and 4(b) shows very good
agreement between the intended and generated ground motions for all threetime durations. There are minor discrepancies as can be observed visually,
but the overall agreement is quite satisfactory. Since the process of groundmotion generation requires accurate representation of the scaled motion inthe ‘Earthquake Plate’, proper connection between the sub-structure and thestructure itself, rigidity of the ground floor, effectiveness of the regulator
and accuracy of the data recording device, these records show the accuracyof the arrangements.
5.2

Numerical and experimental floor deflections

A large number of experimental simulations were carried out tocompare with corresponding numerical results. Deflection time series of all
three floors were calculated and measured experimentally for (i) The
original structure (i.e., no extra weight or soft story), (ii) Adding extra 2 kg
weight at the two top floors of the original structure, (iii) Making the firststory of the original structure soft, (iv) Adding extra 2 kg weight at the two
top floors of the structure of (iii), (v) Making the second story of the original
structure soft, (vi) Adding extra 2 kg weight at the two top floors of thestructure of (v).

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Table 1 and Table 2 show the numerical and experimental peaks for
all the cases studied. Most of the results match quite satisfactorily, withsignificant discrepancies found in 3rd floor deflection for 15 sec simulationof Case (iii) (soft first story without extra weight) and particularly for 15
and 20 sec simulations of Case (v).
Table 1: Peak deflections (cm) without extra weight [Case (i), (iii), (v)].
Time Floor
No Soft Story
Soft 1st Story
Soft 2nd Story
Exp
Num
Exp
Num
Exp
Num
1
3.90
3.46
4.00
3.98
3.90
3.64
15
2
4.90
4.52
4.40
4.29
3.00
4.38
sec
3
5.50
5.13
6.00
4.67
3.90
4.83
1
5.60
4.63
3.80
4.15
3.50
4.13
20
2
5.70
5.48
3.90
4.69
3.90
5.14
sec
3
6.20
5.96
5.50
4.96
3.00
5.50
1
4.00
3.85
5.20
4.66
4.10
4.12
25
2
4.50
4.03
5.60
5.12
4.80
4.79
sec
3
5.00
4.11
5.00
5.37
5.00
5.01
Table 2: Peak deflections (cm) with extra weights [Case (ii), (iv), (vi)].
No Soft Story
Soft 1st Story
Time Floor
Soft 2nd Story
Exp
Num
Exp
Num
Exp
Num
1
4.70
4.44
4.80
5.02
4.20
4.51
15
2
5.30
5.04
6.90
6.27
5.10
6.07
sec
3
6.30
5.81
6.20
6.96
5.75
6.77
1
4.20
3.69
4.00
4.29
4.00
3.91
20
2
4.30
5.05
4.80
4.54
5.25
4.43
sec
3
5.30
5.87
5.00
4.95
5.80
4.88
1
4.70
4.74
4.90
3.99
4.00
3.56
25
2
5.50
5.90
5.10
4.79
3.90
4.49
sec
3
6.30
6.55
5.60
5.25
4.10
4.91
Figures 5~7 show the numerical and experimental time series
variations of selected floor deflections for various time durations (15, 20, 25sec) and experimental arrangements, with Figures (a) showing the numericalresults and Figures (b) the experimental data. The agreement between thetwo is quite satisfactory in general, as shown by visual inspection. The
figures also show the relatively rapid variations of structural motions forstructures without extra weight (Figure 5) and slower variations for theothers (Figures 6 and 7), due to larger time periods caused by extra weights.

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8

6.

D is placem ent (cm )

6
4
2
0
-2
-4
-6
-8
0

5

10

15

20

25

0

5

10

15

20

25

Time (sec)Time (sec)rdFigure 5: 3 Floor displacement (25 sec, no wt, no soft story)(a) Numerical, (b) Experimental
8
D is p lacem en t (cm )

6
4
2
0
-2
-4
-6
0

3

6

9

12

15

0

3

Time (sec)

6

9

12

15

Time (sec)Figure 6: 1st Floor displacement (15 sec, extra wt, soft story1)(a) Numerical, (b) Experimental

D is p lacem en t (cm )

6
4
2
0
-2
-4
-6
0

4

8

12

Time (sec)

16

20

0

4

8

12

16

20

Time (sec)ndFigure 7: 2 Floor displacement (20 sec, extra wt, soft story2)(a) Numerical, (b) Experimental

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6. OBSERVATIONS FOR STRUCTURES WITH SOFT STORIESThe influence of soft stories is a significant aspect of the results from theanalyses. The proper way to show this effect is by observing the relative
floor displacements that eventually lead to column deformations andinternal forces. Table 3 demonstrates selected results from numericalanalysis (for 15 sec simulation) of the laboratory model.
Table 3: Peak column deformation (cm).
No
Soft
Soft
st
Col Soft
2nd
1
Story Story Story
No
1
1.29
1.60
0.92
Wt.
2
1.08
0.69
1.41
Extra 1
1.74
3.32
1.84
Wt.
2
1.35
1.51
2.59

Figure 8: Large column deformation in soft first story
The influence of extra weight and soft story on the relative column
displacements is quite apparent. In general, the peak deformations increasesignificantly (by about 25~125%) after adding extra weights. Moreover,whereas a soft first story with extra weight on the top two floors [Case (iv)]
results in maximum relative column deformations of 3.32 and 1.51 cm in
the 1st and 2nd story respectively, a soft second story with extra weight [Case(vi)] changes these column deformations to 1.84 and 2.59 cm respectively.
All these deformations are quite large compared to the case without softstory (where the maximum column deformations are 1.74 and 1.35 cm
respectively) and result in considerable distress of the soft story columns asshown in Figure 8 during the laboratory simulations.

7. CONCLUSIONSThe paper shows results of numerical and experimental works performed on
the seismic response of 3-storied structural models with and without soft

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December 2007, Dhaka, Bangladesh

stories. A (60 cm × 60 cm) shake table capable of generating defined
earthquake motion was developed (the first such work reported in
Bangladesh) using an indigenous and inexpensive approach. This concept
can be used for developing larger shake tables, the cost of which would
otherwise be prohibitive. The generated ground motions matched almost
exactly with the target data, which validates the process of simulating
defined ground motions.
For almost all the time series simulations performed here (varying
earthquake durations, story stiffness and mass of the structural model), thenumerical results of floor deflections matched very well with theexperimental data, validating the numerical scheme used.
The column deformations of the laboratory model strongly depended
on the presence and location of the soft story as well as extra weight,
demonstrtating the importance of soft stories and structural weight on theseismic response of building structures.

REFERENCES
Anam, I., and Azam, H. M. U., 2006. Seismic behavior of nonlinear RC
frames with masonry infills. 10th East Asia Pacific Conference on
Structural Engineering and Construction, Bangkok, Thailand, Vol 3,
393-398.
Asteris, P. G., 2003. Lateral stiffness of brick masonry infilled plane frames.
ASCE Journal of Structural Engineering 129, 1313-1323.
Azam, H. M. U., and Amanat, K. M., 2005. Effect of infill as a structuralcomponent on the column design of multi-storied building. UAP
Journal of CEE 1, 12-17.
Chopra, A. K., 1995. Dynamics of structures: Theory and applications toearthquake engineering. Prentice-Hall, Inc., NJ, USA.
Engelkirk, R. E., and Hart, G. C., 1984. Earthquake design of concrete
masonry buildings. Vol. 2, Prentice-Hall Inc., NY, USA.
Hossain, M., 1997. Non-linear Finite Element analysis of wall-beam
structures. Ph.D. Thesis, Department. of CE, BUET.
Madan, A., Reinhorn, A. M., Mander, J. B., and Valles, R. E., 1997.
Modeling of masonry infill panels for structural analysis. ASCE
Journal of Structural Engineering 123, 1295-1302.
Manju, F., 2004. Experimental verification of nonlinear dynamic analyses.
B. Sc. Engg. Thesis, Vol. II, Department. of CEE, UAP.
Manju, F., Anwary, A. R., and Anam, I., 2005. Nonlinear seismic analyses
and experimental verification. 3rd Annual Paper Meet andInternational Conference on CE, Dhaka, Bangladesh, 211-222.
Omote, Y., Mayes, R., Chen, S. J., and Clough, R. W., 1977. A literature
survey of transverse strength of masonry walls. Vol. 2, UCB/EERC77/07, The University of California at Berkeley.
Papia, M., 1998. Analysis of infilled frames using a coupled Finite Element
and Boundary Element solution scheme. International Journal of
Numerical Methods in Engineering 26, 731-742.

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Reddy, J. N., 1993. An introduction to the Finite Element method. McGrawHill Inc., NY, USA.
Roy, H., 2007. Numerical and experimental study of structures with softstories. B. Sc. Engg. Thesis, Department. of CE, UAP.
Saneinejad, A., and Hobbs, B., 1995. Inelastic design of infilled frames.
ASCE Journal of Structural Engineering 121, 634-643.

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SEISMIC VULNERABILITY ASSESSMENT
OF RC BUILDINGS OF DHAKA CITY
MOHAMMAD SAJEDUL HUQ1, MOHAMMAD RAFAT SADAT2,MOHAMMAD SALAHUDDIN RIZVI3 and MD. NAFIUL HAQUE4
Undergraduate Students, Department of Civil Engineering, BUET,
Dhaka, Bangladesh
MEHEDI AHMED ANSARY
Professor, Department of Civil Engineering, BUET, Dhaka, Bangladesh
ansary@ce.buet.ac.bd
ABSTRACTThe objective of this study is to assess the seismic vulnerability of RC
buildings of selected area of Dhaka city by FEMA Rapid Visual Screening
method and the Turkish Methods. The areas covered under the survey arepart of Dhanmondi, Lalmatia and a part of the Mohammadpur residential
area. The survey focused on earthquake issues of residential buildings suchas identifying building type, plot size and shape, clear distances fromsurrounding structures, road width and basic information of the building:type of foundation, slab type, year of construction, number of storey,
number of inhabitants etc. The detail analysis using the Turkish level-2
method covered the determination of plinth area (length x width), column
size and direction, lift core size, cantilever length of the building etc.
Digital photographs of each building from at least two directions werecollected. The survey process was conducted between March to May, 2007.
A database consisting of 2007 buildings was compiled in MS Access. Amongthe buildings, 1082 are RC and rest 925 is URM buildings. Among the RC
buildings, 456 have a soft storey. In case of most of the soft storiedbuildings, the ground floor is used as parking space. Use of Rapid Visual
Screening (RVS) and Turkish (level-1) methods to survey the buildings
enable to divide the screened buildings into two categories: those that are
expected to have acceptable seismic performance and those that are
unacceptable and need to be studied further. Those buildings which were
designated as seismically vulnerable by RVS and Turkish (level-1) methods,
more detailed analysis using Turkish (level-2) method and ETABS werecarried out.

1. INTRODUCTION
Reinforced Cement Concrete (RC) frame buildings are becoming
increasingly common in Dhaka city. Many such buildings constructed inrecent times have a special feature – the ground storey is left open for the
purpose of parking, i.e. the columns in the ground floor do not have any
partition walls between them. Such buildings are often termed as ‘SoftStorey’ buildings. Open ground storey buildings have consistently shown103

December 2007, Dhaka, Bangladesh

poor performances during the past earthquakes across the world (forexample during the 1999 Turkey and Taiwan earthquakes, the 2003 Bam
earthquake, the 2001 Bhuj earthquake and the 2005 Kashmir earthquake), a
significant number of them have collapsed. For the past 10 years
Bangladesh has had a boom in Real Estate sector. The prime location has
been Dhanmondi area with further extension in Lalmatia andMohammadpur. Worryingly most of the RC buildings of these areas have asoft storey. The objective of this study is to compile a database of RC
buildings within a specified area of Dhaka City and to assess the earthquake
vulnerability of those buildings using RVS (Rapid Visual Screening)
method (FEMA, 2002) and the Turkish (level 1 and 2) methods (Sucuoglu
and Yazgan, 2003).

2. THE SURVEYED AREA
The area selected for the survey started from Road 32, Dhanmondi up to theend of Ring Road, Mohammadpur. The two parallel boundaries are theSatmasjid Road and the Mirpur Road. Figure 1(a) shows the surveyed area.
Figure 1(b) shows the Sobhanbag pocket with concentration of high-rises.
The reason behind selecting this area is that for the last few years’
realtors were involved in building apartments in this area. These apartments
tend to have a weaker ground storey as most of the structures haveprovisions for parking there. The selected area is basically a residential one.
Recently, it has turned into a semi commercial area with a growth of
Hospitals, Supermarkets, Schools, Universities and commercial structures inan unplanned way.

3. MEHODOLOGY
To assess the buildings of the surveyed area two methodologies were mainly
used namely RVS (Rapid Visual Screening) suggested by FEMA andTurkish methods.
3.1

Rapid Visual Screening

Rapid visual screening (RVS) method of buildings for potential
seismic hazards, originated in 1988 with the publication of the FEMA 154
Report. RVS provides a procedure to identify record and rank buildings thatare potentially seismically hazardous (FEMA, 2002). This screening
methodology is encapsulated in a one-page form, which combines a
description of a building, its layout and occupancy, and a rapid structural
evaluation related to its seismic hazard.

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Figure 1a: Aerial View of Surveyed Area (Dhanmondi Road 32 to Shamoli)

Figure 1b: Sobhanbag Pocket with High Rise Buildings (>10 stories)
Although RVS is applicable to tall buildings, its principal purpose is
to identify (1) older buildings designed and constructed before the adoptionof adequate seismic design and detailing requirements (2) buildings on softor poor soils, and (3) buildings having performance characteristics thatnegatively influence their seismic response. Once identified as potentiallyhazardous, such buildings should be further evaluated by a design
professional experienced in seismic design to determine if, in fact, they areseismically hazardous.
The rapid visual screening method is designed to be implemented
without performing any structural calculations. The procedure utilizes ascoring system that requires the evaluator to (1) identify the primarystructural lateral load-resisting system, and (2) identify building attributes
that modify the seismic performance expected for this lateral load-resisting
system. The inspection, data collection and decision-making process
typically occurs at the building site, and is expected to take around 30
minutes for each building. The screening is based on numerical seismic
hazard and vulnerability score.

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Basic Structural hazard scores for various building types are provided
on the RVS form. The screener modifies the basic structural hazard score byidentifying and circling score modifiers which are then added (orsubtracted) to the basic structural hazard score to arrive at a final structuralscore, S. The basic structural hazard score, score modifiers, the final
structural score S, all relate to the probability of building collapse. The
result of the screening procedure is a final score that may range above 10 or
below 0, with a high score indicating good expected seismic performanceand a low score indicating a potentially hazardous structure. While the scoreis related to the estimated probability of major damage, it is not intended to
be a final engineering judgment of the building, but merely to identify
buildings that may be hazardous and require detailed seismic evaluation. If
the score is 2 or less, a detailed evaluation is recommended. On the basis ofdetailed evaluation, engineering analysis and other detailed procedures, a
final determination of seismic adequacy and need for rehabilitations can be
made. Figure 2 shows a sample RVS scoring form.

Figure 2: Sample RVS Scoring Form for High Seismicity Zone
(after FEMA, 2002)
3.2

Turkish Method

In recent times, after the 1999 earthquake in the cities of Kocaeli andDuzce, Government of Turkey and Japan International Cooperation Agency(JICA) came forward for implementing a regional seismic assessment andrehabilitation program. Researchers from various universities were involvedin this program supported by the Government of Turkey and JICA. A simple
Two-level Seismic Assessment Procedure for a building stock was proposed(Sucuoglu and Yazgan; 2003). In this study, most vulnerable buildings that
may undergo severe damage in a future earthquake are identified. A surveyof 477 damaged buildings (1-7 storey) affected by Duzce earthquake(November 1999) was carried out. This was then complied to form a
database of damaged buildings to be used for future research work. This
database was employed for developing the performance score (PS) equation
to determine the vulnerability of a reinforced concrete building. Figure 3
shows a sample Turkish Form.

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Figure 3: Tables and General Equation of Turkish Procedure (after Sucuoglu
and Yazgan, 2003)

3.2.1 Level-1 Survey
The trained observers collect data through walk-down visits. The
parameters that are selected in Level-1 survey for representing building
vulnerability are the following:a. The number of stories above groundb. Presence of a soft story (Yes of No)
c. Presence of heavy overhangs, such as balconies with concrete parapets(yes or No)
d. Apparent building quality (Good, Moderate or Poor)e. Pounding between adjacent buildings (Yes or No)
f. Local soil conditions (Stiff or Soft)g. Topographic effects (Yes or No)
All of the above parameters are found to have a negative feature on thebuilding system under earthquake excitations on a variable scale
3.2.2 Level-2 Survey
A Level 2 survey is done for the buildings when those are found to befalling into the moderate and high-risk levels using level 1 risk assessment.
The trained observer teams enter into the basements and ground stories of
those buildings for collecting more data for Level 2 risk assessment. Their
first task is to confirm or modify the previous grading by Level-1 method on
soft stories, short columns and building quality, through closer observation.
The second and more elaborate task is to prepare a sketch of the groundfloor plan and measure the dimensions of columns, concrete and masonry

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walls. This data is then employed for calculating the Redundancy andStrength Index parameters.
Once the vulnerability parameters of a building are obtained from twolevel surveys and its location is determined, the seismic performance scoresfor survey levels 1 and 2 are calculated by using Tables A and B
respectively as shown in Fig 3. In these Tables, an initial score is given firstwith respect to the number of stories and intensity zone. Then the initialscore is reduced for every vulnerability parameter that is observed or
calculated. A general equation for calculating performance score (PS) can
be formulated as follows:
PS = (Initial Score – ∑ (Vulnerability parameter) X (Vulnerability Score)Cut-off value for seismic performance score (PS) is 50. Table C in
Figure 3 presents all the vulnerability parameters used in Turkish Method.

4. COLLECTION OF BUILDING DATA
The areas covered under the survey are part of Dhanmondi, Lalmatia andpart of Mohammadpur residential area. The survey was mainly focused onearthquake issues such as identifying building type, plot size and shape,
clear distances from surrounding structures, road width and basic
information of the building: type of foundation, slab type, year of
construction, number of storey, number of inhabitants etc. The detailanalysis (or the Turkish level-2 analysis) covered the determination of plinth
area (length x width), column size and direction, lift core size, cantilever
length of the building etc. Digital photographs of each building from at least
two directions were taken. The developers’ names concerned with eachbuilding are also recorded during the survey. Detailed data were collected
for 10% of the buildings for Turkish Level-2 analysis, which includes
column and lift core dimensions and other relevant parameters. The data
was then compiled in an MS-ACCESS Database. With the help of thedatabase, analysis of the building stocks of the area under survey was
possible. Figure 4 shows a sample of the database and Figure 5 shows two
sample buildings.

5. DATA ANALYSISThe compiled database has 2007 building data stored for the surveyed area.
Out of these, 1082 buildings are RC buildings and the rest 925 buildings are
un-reinforced masonry (URM). Among the RC buildings 456 have soft
storey.
Figure 6 shows the relation between number of buildings and numberof storey. From this figure, it is evident that 6 storied buildings are
predominant, as the RAJUK does not give permission to build structures
more than 6 storey within the residential areas. There are some higher storey
buildings outside the RAJUK area within Dhanmondi located between

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Sobhanbag Mosque and Road number 25. (high rise pocket as shown in Fig.
1b). Also a few high rises are located at Lalmatia and Mohammadpur areas.
Figure 7 shows the relation between numbers of buildings with presence ofoverhangs. The figure indicates most buildings tend to have overhang(mostly verandah). Heavy overhang makes a structure risky for earthquake
according to the Turkish Method. Figure 8 shows the relation between
numbers of buildings, plinth area and the number of storey. This figure also
shows that 6 storey buildings are dominant. Among those most of themranged around 2000-3000sft or>5000sft.

Figure 4: Sample of Microsoft Access Database

Figure 5: Building with a soft story and building with a heavy overhang
Figure 9 shows the relation between numbers of buildings andcorresponding RVS Score. Buildings having a score <2 are considered to be
dangerous in this method. Around sixty buildings were found to be
dangerous. However, it should also be noted that the actual damage would
depend on a number of factors that are not included in the RVS procedure.
As a result, the implications should only be used as indicative to determine

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the necessity of carrying out simplified vulnerability assessment of thebuildings. These results can also be used to determine the necessity ofretrofitting buildings where more comprehensive vulnerability assessment
may not be feasible.
Number of Buildings

400
350
300
250
200
150
100
50
0

1

2

3

4

5

6

7

8

9

10

>10

Storey Number

Figure 6: Relations between number of buildings and Number of Storey

Number of Buildings

140
120
100
80
60
40
20
0

0.00

1.00

2.00

3.00

4.00

5.00

6.00

Overhang Length, (ft)Figure 7: Relations between number of buildings and Overhang Length (ft)Number of Buildings

120
100
80
60

<2000

40

2000-3000

20

3000-4000

04000-5000
1

2,3
S tor

ey

4,5

Area (sft)

>5000
6,7

>7

Figure 8: Relations between Number of Buildings, Number of Storey and
Plinth Area (sft)110

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Figure 10 shows the relation between numbers of buildings andcorresponding score of Turkish Level-1 method. Buildings having a score>50 are considered to be safe in this method. In this method much morevariation in final scores has been observed as not only the basic score but
also the influences of vulnerability parameters are very much dependent on
the height of the building. In fact the positive or negative score
modifications due to vulnerability parameters are weighted multiplications
based on their existence and number of stories of the buildings (Imtiaz et al.,2007). As a result the score becomes high for low-rise buildings in spite ofpresence of negatively influential vulnerability parameters. Due to thesedependant variations, it is comparatively tougher task here to classify thedamage probabilities with minute specifications, as that of RVS-FEMA
method, only from final scores. Rather it is easier to indicate an overall viewon safety of the building comparing the final score with the cut off value
and observing their relative difference. In this analysis, all buildings havehigher score than the cut-off value.
Though the buildings identified as unsafe or lower scored compared to
the “cut-off” value in Level-1 were supposed to be judged by Level-2
procedure, in this investigation around 10% buildings were analyzed again
in the Level-1 to see the difference of score variations between these two
methods. Figure 11 compare the scores of buildings according to Level-1
and Level-2 survey. From the results represented in Figure 11, it can beobserved that around fifty buildings which have more than the cut-off value
in Level-1 method has smaller score than the cut-off value in the Level-2
method. This reduction of score can be attributed to factors such as plan
irregularity, redundancy, strength index parameters in Level-2 method.

Number of Buildings

300
250
200
150
100
50
0
<1.7

1.7-1.9

2.0-2.2

2.3-2.5

2.6-2.8

2.9-3.1

3.2-3.6

Building Score

Figure 9: Relation between Number of Buildings and Building Score(RVS)
Number of Buildings

300
250
200
150
100
50
0
≤50

>50-≤60>60-≤70<70-≤80<80-≤90<90-≤100>100

Building Score

Figure 10: Relation between Number of Buildings and Building
Score (Turkish Level-1)
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December 2007, Dhaka, Bangladesh
35

Level-2

Level-1>60-≤70>70

Number of Buildings

30
25
20
15
10
5
0

≤20

>20-≤30>30-≤40>40-≤50>50-≤60

Building Score

Figure 11: Relation between Number of Buildings and Building Score(Turkish methods)
6. CONCLUSIONSIn this paper, results and analysis of a building survey in some residential
area of Dhaka city was presented. The analysis was basically conductedusing FEMA’s RVS method and Turkish Level 1 and 2 methods. The
evaluation of two different methods in this paper has enabled the criticalexamination of the advantages and shortcomings of the methods. The
Turkish method was found more significant with respect to applicability in
our study region but from the experience of survey it is observed that thestructural measurement in Level-2, which acts as very importantvulnerability features, has made the method somewhat tougher as building
owners in the survey area do not cooperate with the screeners and restrict
their entry to the ground floor.

REFERENCES
FEMA154, 2002. Rapid Visual Screening of Building for Potential Seismic
Hazards: A Hand Book.
Imtiaz, A. B. A., Shamim, M., Dhar, A.S., Ansary, M.A., Ahmed, Z. and
Ahmed, M. Z. 2007. Visual Screening Methods for Earthquake
Vulnerability Assessment. USMCA2007, Dhaka, Bangladesh.
Sucuoglu, H. And Yazgan, U. (2003). Simple Survey Procedures for
Seismic Risk Assessment In Urban Building Stocks. Seismic
Assessment and Rehabilitation of Existing Buildings, 97-118, NATO
Science Series, IV/29, Editors: S.T. Wasti and G. Ozcebe, Kluwer

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ASSESSMENT OF CYCLONESHELTERS IN COX’S BAZAR AGAINSTEARTHQUAKE HAZARD
RAJAN SAHA
Research Assistant, Department of Civil Engineering, BUET, Bangladesh
rajanbuet00@yahoo.com
ASHUTOSH SUTRADHAR
Associate Professor, Department of Civil Engineering, BUET, Bangladesh
asuthoshdhar@buet.ac.bd
MEHEDI AHMED ANSARY
Professor, Department of Civil Engineering, BUET, Bangladesh
ansaryma@yahoo.com
ABSTRACT
Cyclone Shelters in Cox’s Bazar district of Bangladesh has beenassessed for earthquake vulnerability. Federal Emergency Management
Agency (FEMA) method has been used for Rapid Visual Screening (RVS)
for the evaluation. It is revealed from RVS that all of the cyclone shelters
are vulnerable to earthquake loads. Detailed analysis of structures also
showed similar findings. However, lack of lateral support system increased
the vulnerability of the structure. Introduction of lateral supports in theform of diagonal beam appeared to improve the performance of the cyclone
shelters under earthquake loads.

1. INTRODUCTION
Bangladesh is a part of the Bengal basin which is one of the mostseismically active zones of the world. Lying as it does in the confluence of
the India, Burma and Eurasia plate, the land is extremely prone toearthquake disasters and in the past have experienced some of the worst
earthquakes in the history. Figure 1 shows world’s seismic sources andlocation of Bangladesh. It is revealed from the figure that Bangladesh issituated at one of the densely located earthquake sources. Earthquake
sources around Bangladesh are shown in Figure 2, indicating high potentialof earthquake. The district of Cox’s Bazar is located in south eastern part of
Bangladesh (as shown in Figure 2). It is the largest sea beach in the world of
200 km length. Figure 3 shows the earthquake sources identified around the
city.

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Figure 1: Earthquake sources Global view,(British Geological Survey)

Cox's Bazar

Figure 2: Location of Study area and Earthquake sources with respect toBangladesh (after Noor et.al, 2005)

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Cox’s Bazar known to be as coastal district and famous for tourism.
However the city is prone to various natural disasters, affecting lives andlivelihood frequently. Cyclone attacked in this area in 1970, 1986, 1991 and1997. 1970 and 1991 Cyclones were devastative. Besides, every year atleast two or three times this area is threatened by cyclone. After the 1991
cyclone, the Government of Bangladesh made a policy for the protection ofcoastal people. For this, RCC frame structure buildings of two to threestoried were constructed. These buildings are known as cyclone shelters.
Almost all the shelters belong to Government of Bangladesh; some shelters
are supervised by non government organizations. The buildings are ofrectangular and V shape. Some buildings are of irregular shape.

Figure 3: Historical earthquakes around Cox’s Bazar.

2. SEISMIC VULNERABILITY ASSESSMENT
Assessment of the buildings is usually performed in three levels. Threelevels are briefly described following:
Level 1: This procedure requiring only visual evaluation.
Level 2: Simplified vulnerability assessment procedure requiring limited
engineering analysis based on information from visual observations andstructural drawings or on site measurements. The method is widely known
as Rapid Visual Screening (RVS) method.

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Level 3: Detailed vulnerability assessment procedure requiring detailed
complex analysis. This procedure is recommended for all important andlifeline buildings.
2.1

RVS Methodology

Rapid visual screening (RVS) of buildings for potential seismic
hazards, originated in 1988 with the publication of the FEMA 154 Report,
Rapid Visual Screening of Buildings for Potential Seismic Hazards a
Handbook. RVS provides a procedure to identify record and rank buildingsthat are potentially seismically hazardous (FEMA, 2002). This screening
methodology is encapsulated in a one-page form, which combines a
description of a building, its layout and occupancy, and a rapid structural
evaluation related to its seismic hazard.
Although RVS is applicable to tall buildings, its principal purpose is to
identify (1) older buildings designed and constructed before the adoption ofadequate seismic design and detailing requirements (2) buildings on soft orpoor soils, or (3) buildings having performance characteristics thatnegatively influence their seismic response. Once identified as potentiallyhazardous, such buildings should be further evaluated by a design
professional experienced in seismic design to determine if, in fact, they areseismically hazardous.
2.2

RVS Analysis of Cyclone Shelters

Cyclone Shelters are visually observed in the study area. Most cyclone
shelters are of rectangular and V shaped and few of irregular shape. Figure 4
shows building shape variation of cyclone shelters under investigation. A
sample RVS sheet of a rectangular shaped cyclone shelter is shown in
Figure 5. This cyclone shelter shown in Figure 5 is of rectangular shape andof Reinforced Concrete Frame Structure with unreinforced masonry infill. It
is categorized by URM INF in RVS sheet. URM INF (C3) has a basic scoreof 1.6 according to FEMA RVS method. Since there is no irregularity in theplan so there is no score for plan and vertical irregularity. There is apresence of soft storey in the building. According to FEMA 154 (2002) soft
storey in a storey is identified where the lateral stiffness is less than 70% ofthat in the storey above or less than 80% of the average stiffness of thestories above. Soft storey is considered as vertical irregularity and score is-1 which is negative. Soil Type D is chosen because the area is in the hilly
region. Thus the total score of the rectangular cyclone shelter has beenfound to be 0.2, which is less than the ‘cut-off` score of ‘2` according to
FEMA 154 (2002). Thus the building requires detailed analysis.

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Figure 4: Building Shapes of Cyclone Shelters at Cox’s Bazar

RVS Sheet for V-Shaped cyclone shelter is shown in Figure 6.
Another parameter for plan irregularity is included for these types of shelter.
There is a negative score and it is -0.5 for plan irregularity according to
FEMA. As a result, the score for the V-Shaped cyclone shelter became -0.3.
Rectangular shape cyclone shelters without soft storey showed RVS scoreof 1.2 and irregular shaped shelters without soft storey showed RVS scoreof 0.7.

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Figure 5: Sample RVS Sheet for Rectangular Shaped Shelter

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Figure 6: Sample RVS Sheet for V Shaped Cyclone Shelters

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V Shape and Irregular with soft storey

Rectangular with soft storey

Irregular without soft storey

Rectangular without soft storey

December 2007, Dhaka, Bangladesh

Figure 7: RVS Score variation
About 268 Cyclone shelters across Cox’s Bazar has been analyzed
using RVS method. RVS scores for the different types of cyclone shelter are
shown in Figure 7. Almost all the building’s score is less than 2. (The Cut
off score) and thus detail evaluations of these are required. The low score in
RVS of the system is due to the low basic score for the system with nolateral support. Detail analysis was also done on some buildings aspresented in the following article. The effect of lateral support in the form of
2-diagonal beam has been explored in the detailed analysis.
2.3

Detailed Analysis of Cyclone Shelters

It is revealed that all of the cyclone shelter possesses RVS score lessthan the ‘Cut off` score and therefore, require detailed analysis. Detailed
analysis has been performed for a rectangular, a V-Shaped and an irregularshaped cyclone shelters. Analysis was performed using commerciallyavailable structural analysis software called ‘ETABS` (Extended Three
Dimensional Analysis of Building Structures). The first mode shape whichis the lateral deflection of the ground floor level of the structure, wasconsidered from the dynamic analysis of structures using ETABS. The
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govern the earthquake design. The same deformation shape in the otherdirection (orthogonal) is termed as 2nd mode shape in ETABS, which may
have the maximum natural period and therefore investigated here.

Figure 8: Mode Shape 1 for Rectangular Shaped Cyclone Shelter(Period 0.35 sec)
Figure 8 shows 1st mode shape of the Rectangular shaped cyclone
shelter. Natural time period for that mode was 0.35 sec. Natural period forMode shape 2 was also 0.35 sec, since the building has similar geometry inthe other (perpendicular) direction. First modal and second modal
deformation of the V-shaped cyclone shelter is shown in Figure 9 and 10.
Even though, the geometry is different in two perpendicular directions forthe cyclone shelter, the natural period for the two modes are approximately
same (0.29 sec). It is also to be noted here that natural period for the Vshaped shelter are less than the rectangular shelters, indicating betterstability against earthquakes. Low time period for V-shaped shelter can be
due to less number of storey for the shelter (2-storied) with reference to therectangular shelter (3 storied). Figures 11 and 12 show the mode shapes 1
and 2 of a irregular shaped cyclone shelter. The irregular shaped shelter
showed natural period of 0.51 sec and 0.5 sec respectively for the two modeshapes, which are greater than both of the V-shaped and Rectangular shaped
cyclone shelters.
RVS scores and natural time periods for each type of the cyclone
shelters are shown in Table 1. It is revealed that RVS score is the highest forrectangular shaped structure with no soft storey while the lowest for the VShaped structures. Thus the V-Shaped shelter is expected to be the worst
under earthquake. However detailed analysis showed the lowest natural time
period, indicating the best among the shelters. The contrary of theconclusion of the two methods indicating that further attention is required

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regarding revision of the RVS methods to incorporate other necessary
parameters such that both methods provide similar conclusion.
Table 1: RVS Score and Natural time period for cyclone shelter
Building Type RVS Score withRVS Score
Natural Timesoft storey
without soft
Period form
storeyAnalysis
Rectangular
0.2
1.2
0.35
V-Shape
-0.3
0.7
0.29
Irregular
-0.3
0.7
0.5

Figure 9: Mode Shape 1 for V Shaped building (Period 0.29 sec)

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Figure 10: Mode Shape 2 for V Shaped building (Period 0.289 sec)

Figure 11: Mode Shape 1 for Irregular Shaped Building (Period 0.51 sec)

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Figure 12: Mode Shape 3 for Irregular Shaped Building (Period 0.5 sec)

Empirical correlation between number of storey and natural period ofbuilding for RCC frame buildings and masonry buildings for different
building in Bangladesh was obtained as (BNUS, 2006):
T = 0.04N+0.133[for RCC frame buildings]
T = 0.06N[for masonry buildings]
Where,
T = Natural Period of building
N=Number of Storey

(1)
(2)

The National Building Code (NBC) of Canada defined the natural
period of a building by the following empirical equation:
T=0.1N(3)
Where N = Number of Storey.
From the equation (1) the natural period calculated for three storiedbuilding is 0.25 sec and for two storied building 0.21 sec. From equation (3)it was 0.3 sec and 0.2 sec respectively. The natural period of a building
should not be larger than the equation (3) by a factor 1.2 (Amanat andHoque, 2005). Thus the time period obtained from Eq. (1) and (3) are on
the conservative side. However, the natural period obtained for the cyclone
shelter from the analysis using ETABS are greater than those given by Eq.
(3), indicating that the cyclone shelters are on unconservative side forearthquake loads. A study has been performed with introduction of a lateralsupport in the form of two diagonal beams on each side at ground floor level
for the rectangular cyclone shelter.

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Bracing

Figure 13: Mode Shape for rectangular shaped shelter with diagonalbracing (0.26 sec)
From the analysis with diagonal bracing the natural period was found0.26 sec which is lower than the value calculated by Eq. (3) and therefore it
is on conservative side. Thus introduction of lateral bracing may improve
the performance of the cyclone shelters under earthquake loads.

3. CONCLUSIONS
About 268 cyclone shelters across the district of Cox’s Bazar in Bangladesh
have been evaluated for their vulnerability to earthquake loads. Both rapid
visual screening (RVS) method and detailed analysis have been used in thisinvestigation. In the rapid visual method the score for all of the cyclone
shelter were less than the cut off score, indicating that the structures arevulnerable. Similar finding was obtained from detailed analysis. Detailed
analysis performed using ETABS showed the natural time period for 1st
mode of deformation to be greater than the limiting time period. Thus the
structure showed less stiffness for that mode of deformation. The greater
natural time periods for the structures were due to lack of lateral support
system. Analysis performed introducing diagonal bracing resulted in
reduction of the natural time period within the limiting value. The RVS
method and the detailed analysis showed contradictory conclusion regarding
performance of different types of structures. While score rate the V-Shaped
structure to be the worst, detailed analysis showed it to be the best. Thus
further study may be required for revision of the RVS method to include
other necessary parameters that bring the both methods to have the sameconclusion.

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REFERENCES
Amanat, K.M. and Hoque, E. 2005. A rationale for determining the natural
period of RC building frames having infill, Engg. Structures Vol. 28,
pp 495-502.
Bangladesh National Building Code, 1993. Housing and Building ResearchInstitute, 1st ed., Dhaka.
BNUS Report, 2006. Evaluation of the seismic vulnerability of Bangladeshi
buildings using non-destructive testing, ICUS Report No. 2006-2007.
FEMA 154, 2002. A Handbook: Rapid Visual Screening of Buildings for
Potential Seismic Hazards, 2nd Edition.
Noor, M.A. Yasin, M and Ansary, M.A., 2005. Seismic Hazard Analysis of
Bangladesh, Proceedings First Bangladesh Earthquake Symposium.
Saha, R., 2006. Earthquake Vulnerability Assessment of BUET Buildings.
Undergraduate Thesis, Department of Civil Engg., BUET, Dhaka.
Uniform Building Code, 1994.

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PARTIALLY ENCASED COMPOSITECOLUMNS: AN INNOVATIVE COMPOSITESTRUCTURAL SYSTEM
MAHBUBA BEGUM
Assistant Professor, Department of Civil Engineering, Bangladesh
University of Engineering and Technology (BUET), Dhaka, Bangladesh
mahbuba@ce.buet.ac.bd
ABSTRACTOne of the recent developments in composite systems includes
partially encased composite (PEC) columns consisting of a thin-walled,
welded I-shaped steel section with concrete infill cast between the flanges.
Transverse links are provided between the flanges at regular intervals toenhance the resistance to local instability of the thin steel plates. This
innovative composite system not only reduces the cost of construction using
relatively low-cost concrete by minimizing the use of higher cost steel, butalso helps to overcome the complexities related to erection and design ofconnections of more commonly used composite columns. Several researchworks including both numerical and experimental works have been carriedout for establishing the behaviour and the design provisions for this new
type of composite column under various loading conditions. This paper
presents a brief review of these research works along with the capacity
prediction model for this column. The review also includes the design
requirements according to CSA standard S16-01.

1. INTRODUCTION
The effective use of a combination of steel with concrete can substantially
improve the behaviour and cost efficiency of columns used in theconstruction of medium to high-rise buildings, as compared to using
steel-only columns. Two types of composite columns commonly used in
North America are: concrete filled tubes (CFT) and fully encased composite(FEC) columns (Figure 1). Both of these composite systems have limitations
such as limited cross-sectional dimensions of standard shapes (CFT),
requirement of extensive formwork and additional reinforcing steel (FEC
columns) and complex beam-to-column connections. These limitations haveindirectly imposed restrictions on the use of composite columns.

(a)

(b)

Figure 1: Common types of Composite columns, (a) Concrete Filled Tubes
and (b) Fully Encased Composite Column.

127December 2007, Dhaka, Bangladesh

In Europe, in the early 1980s, PEC columns and beams wereintroduced using standard-sized rolled steel sections. In 1996, the CanamGroup in Canada took the initiative to propose a new type of composite
column consisting of a thin-walled, welded H-shaped steel section, built-up
from hot-rolled steel plate, with concrete infill cast between the flanges, as
shown in Figure 2. Transverse links are provided between the flanges atregular intervals to improve the resistance to local buckling. This new
system has been termed the “partially encased composite (PEC) column,”
since the steel section is only partially encased by the concrete. Additional
reinforcement consisting of longitudinal and transverse rebars can beprovided to improve the ductility of these columns under cyclic loading.

Welded H
steel shape
t
Link
d

t

Concrete
b

bf

(a)

(b)

Figure 2: Partially Encased Composite Column with Thin-Walled Built-Up
Steel Section, (a) Column Cross-Section and (b) 3D view of theSteel Configuration.
In PEC columns, since a built–up steel section is used instead of astandard shape, the designer has more flexibility when sizing the column
cross-section. Moreover, thin steel plates are intentionally specified toobtain a more cost effective column by increasing the contribution of
concrete in the load carrying capacity of the column. These factors havemade PEC columns constructed with built-up shapes more attractive thanthose constructed with standard sections. Moreover, the high stiffness of the
PEC column is expected to have beneficial effects for controlling the lateraldeflection of buildings when used as a component of lateral load resisting
systems and incorporating the use of high performance materials in thesystem. To introduce and understand the behaviour of this new composite
system a brief review of the research works, including both experimental
and numerical studies are presented in this paper. The capacity prediction
models for PEC columns are also included along with the design guidelines
as per CSA standard S16-01 (CSA, 2001).

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2. EXPERIMENTAL INVESTIGATIONSExtensive experimental research has been conducted on thin-walled PEC
columns with built–up sections by several research groups (Fillion 1998;
Tremblay et al. 1998; Chicoine et al. 2000; Bouchereau and Toupin 2003;
Prickett and Driver 2006; Begum et al. 2007) to investigate the behaviour of
PEC columns fabricated with thin-walled built-up sections. Descriptions ofthese experimental investigations are presented in the following sections.
2.1

Short Columns Constructed with Normal Strength Concrete

The first series of tests on short PEC columns was performed by
Fillion (1998) and Tremblay et al. (1998) on specimens with
300 mm × 300 mm and 450 mm × 450 mm cross–sections. The specimens
had a length of five times the cross-section dimension and were loaded
under axial compression. The cross-section and elevation of a typical test
specimen is shown in Figure 3. To study the possible size effect on the
behaviour of short PEC columns, Chicoine et al. (2000) tested five
600 mm×600 mm concentrically loaded columns and compared them withthe first series of tests on short PEC specimens. The test specimens were
designed with variable transverse link spacing and the flange slenderness
ratio to study their influences on the column behaviour. A typical test
specimen is shown in Figure 3 (a).
Bouchereau and Toupin (2003) conducted tests to investigate thebehaviour of short PEC columns subjected to axial compression andbending under monotonic and cyclic loading conditions. A total of 22 tests
on 2250 mm long columns were performed. The column cross-section was
450 mm × 450 mm × 9.53 mm where the first two numbers indicate thedepth and width of the cross-section and the third number is the thickness ofthe steel plates. A link spacing of 300 mm was used in all the test columns.
The test program (Bouchereau and Toupin 2003) was mainly designed tosimulate the conditions of a column of the bracing bents subjected tomonotonic and cyclic eccentric axial loads. In each case the effect of strong
and weak axis bending was investigated for two different values of load
eccentricity.
The results of these tests revealed that the failure of the composite
columns (Figure 3 (b)) occurred by a combination of local buckling of thesteel flanges between the transverse links, yielding of the steel and crushingof the concrete. However, Bouchereau and Toupin (2003) reported that theoccurrence of local buckling and concrete crushing was essentiallysimultaneous in all of the eccentrically loaded test specimens. The
specimens with weak axis bending exhibited brittle and explosive failures ascompared to other specimens. The load versus deformation response wasstudied for the test specimens to evaluate the influence of column size, plate
slenderness ratio, link spacing and additional reinforcements. It wasreported that the specimens with higher b/t and s/d ratios exhibited a faster
degradation of post-peak strength than columns with lower b/t ratios andsmaller link spacings (Chicoine et al. 2000). The presence of additional

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reinforcement in the specimens under weak axis bending was observed to
improve the behaviour of these columns significantly. The additional
reinforcements also increased the ultimate capacity of the PEC columns by
an average of 8%, as observed by Bouchereau and Toupin (2003).
Comparing the results of the cyclic tests to corresponding monotonic tests,
no significant differences in the column behaviour were observed.
Link
Welded H
steel shape

t

b
bf

t
d = bf(a)
End platedTest region

3d
s
d

(b)

End region(with closer linkspacing and highstrength concrete)(c)Figure 3: Typical PEC Test Column, (a) Cross-section, (b) Elevation and(c) Failure Mode (Chicoine et al. 2000).
2.2

Short Columns Constructed with High Performance Concrete

Prickett and Driver (2006) conducted a comprehensive experimental
research project to study the behaviour of thin-walled PEC columns madewith high performance concrete. The study included 11 short PEC columns
measuring 400 mm × 400 mm × 2000 mm, with the primary variables being
the concrete type, link spacing and load eccentricity. The plate slenderness
ratio was kept constant (b/t = 25) for all of the test columns. Three different
link spacings and three types of concrete (normal strength, high strength andhigh strength steel fibre reinforced concrete) were used in these specimens.
Steel fibres were used to observe potential improvement in the failure modeof PEC columns with high strength concrete. Four identical PEC columns
constructed with high strength concrete and subjected to axial compression
and bending were also tested by Prickett and Driver (2006). Bending axis

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and the amount of load eccentricity were varied to determine the effects ofthese parameters on the column behaviour.
As observed in the experiments, the high strength concrete PEC
columns failed in a similar manner to the PEC columns with normal
strength concrete: concrete crushing combined with local flange buckling.
However, the failure of a high strength concrete column was found to besudden as compared to an equivalent PEC column with normal strength
concrete. Addition of steel fibres in the high strength concrete was found to
improve the failure mode of the columns somewhat. Prickett and Driver(2006) also studied the moment versus curvature response and developed
load versus moment interaction diagrams for the eccentrically loaded
specimens. The moment versus curvature curves for specimens with strong
axis bending showed a gradual decline of the peak moment as compared tothe sudden decline observed in the specimens with weak axis bending.
2.3

Long Columns Constructed with Normal Strength Concrete

Four long PEC columns with a length-to-depth ratio of 20 were tested
to study the overall buckling behaviour of these columns under monotonic
loading (Chicoine et al 2000). All columns had a square cross-section of
450 mm × 450 mm and a flange slenderness ratio of 23. Additional
reinforcements in the form of longitudinal and tie bars were provided in oneof the composite specimens. The long columns were tested under concentricloading, except for one, which was tested with an eccentricity of 0.06d
about the weak axis. The test results demonstrated the brittle and explosive
failure modes of the long composite specimens that consisted of global
flexural buckling along with local buckling and concrete crushing between
two links. The ultimate capacities of the slender columns were observed to
be about 80% of those of short columns with similar cross–sections and linkspacings. The additional reinforcement was observed to provide no
improvement in the ductility of the long composite column, as opposed tothe beneficial effect observed in the short composite columns.

3. NUMERICAL SIMULATIONS
A finite element model of PEC columns with thin–walled built–up sections
was first developed by Maranda (1998), using the computer program MEF,
to simulate the series of tests on PEC stub columns performed by Tremblay
et al. (1998). Only a quarter cross–section was modelled using shellelements for the steel plate, solid elements for the concrete and beam
elements for the transverse links. Good agreement was observed between
the numerical and the experimental results. However, the model developedby Maranda (1998) was not capable of predicting the post-peak responses of
the test specimens.
Chicoine et al. (2002b) performed a finite element analysis using
ABAQUS/Standard (HKS 2003) to reproduce numerically the behaviour ofthe composite column under axial compression only. Similar to thePartially Encased Composite Columns: An Innovative Composite Structural System

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numerical study performed by Maranda (1998), Chicoine et al (2002b) alsomodelled a quarter of the column cross–section with a length of one linkspacing. The finite element model was developed using shell elements forthe steel section, brick elements for concrete and beam elements for thetransverse links. Two node spring elements were used to represent theinteraction between steel and concrete at their common interface. Steelmaterial behaviour was represented by a bilinear stress–strain curve basedon the typical stress–strain curves obtained from tension coupon tests of theplates used in the column specimens (Chicoine et al 2000). The cracking
model in ABAQUS/Standard was used by Chicoine et al (2002) to represent
the concrete material behaviour in PEC columns. Chicoine et al. (2002) used
the Riks displacement control technique to simulate the applied loading
conditions in the test specimens.
The finite element model developed by Chicoine et al. (2002b)
provided a very good representation of the capacity and load versus
displacement response of short PEC test specimens (Tremblay et al. 1998;
Chicoine et al. 2000) up to the ultimate load. The post-peak response of thecolumns was obtained only over a short deformation range due toconvergence problems experienced by the numerical model. This can be
attributed to the inadequacy of the implicit solution method for representing
the highly nonlinear post-peak behaviour. The researchers identified
significant challenges in simulating the local instability of the thin flanges
and the triaxial behaviour of the partially confined concrete in the column.
Begum et al. (2007) were able to overcome the challenges innumerically simulating the behaviour of PEC columns. A complete finite
element model including the full cross-section and entire length of thecolumn was developed using the explicit module of ABAQUS finite
element code (Begum et al. 2007). The model is applicable for concentric
as well as eccentric loads. The finite element model along with the meshconfiguration for a typical part between two consecutive links is shown in
Figure 4. The steel plates were modelled using four node shell elements.
Eight-node brick elements were used for concrete and beam elements fortransverse links. A dynamic explicit solution strategy was implemented to
trace a stable post-peak response in the load–deformation curve. The steel–concrete interface in the composite column was simulated using a contact
pair algorithm. To represent the concrete material behaviour under partial
confinement, the damage plasticity model in ABAQUS was implemented.
Begum et al. (2007) used the developed model for PEC columns to
reproduce the test results of 12 normal strength, seven high strength and twosteel fibre reinforced high strength concrete PEC columns. The averageexperimental-to-numerical ratios of the peak load obtained were: 1.01, 0.99
and 1.08, respectively, for normal strength, high strength and steel fibre
reinforced high strength concrete PEC columns with standard deviations allless than 0.05. Moreover, the numerical load versus axial strain responses
for the test columns were in very good agreement with the experimental
responses. The failure in all the specimens observed in the numericalanalyses was due to the initiation of local instability of the flange plate

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between two transverse links followed by crushing of the adjacent concrete.
Similar behavior was observed in the experiments. Figure 5 shows
comparison between the experimental and numerical results for a typical
PEC column. The full model also represented the axial capacity of the threelong PEC test specimens (L/d = 20) with good accuracy with an averageexperimental-to-numerical ratio of 0.98.
Web

FlangeEndregionLinks

s = 0.5d
Web
Concrete

Test
regionFlanges

2Endregion13Concrete

Flange(b)(a)

Load (kN)

Figure 4: Finite Element Mesh Developed by Begum et al. (2007),(a) Typical Short Column Displaying the Parts between
Consecutive Links, and (b) Mesh Configuration of a TypicalPart in the Test Region of the Column.
14000
12000
10000
8000
6000
4000
2000
0

FEM
Test

0

2000 4000 6000 8000 10000 12000
Strain (με)

(a)

(b)
Figure 5: Comparison of Experimental and Numerical Results, (a) Load vs.
Displacement Response and (b) Failure Mode.
A comprehensive parametric analysis was performed by
Begum et al. (2007) to study the behaviour of PEC columns subjected toaxial compression and bending about the strong axis. The parameters thatwere varied include the overall column slenderness ratio, load eccentricity
ratio, link spacing-to-depth ratio, plate slenderness ratio and concrete
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compressive strength. The results of the parametric analysis revealed thatthe axial capacity of a PEC column reduces as the overall slenderness ratio
increases, particularly for columns with slender plates. As the plate
slenderness ratio increases, the axial capacity of the column reduces, as
expected, with increased brittleness in the failure behaviour. On the other
hand, the brittle behaviour of long PEC columns is not affected by the b/t
ratio. Thus, the advantage of using stockier flange plates diminishes as thecolumn becomes slender. The axial capacity of the PEC column is greatly(average increase is 55%) improved by the use of high strength concrete
instead of normal strength concrete. However, the load–deformation
response of high strength concrete PEC columns exhibited brittle failure ascompared to the normal strength concrete columns.

4. PREDICTION OF PEC COLUMN CAPACITY
4.1

Columns under Concentric Axial Loading

The experimental and numerical investigations on PEC columns withbuilt-up sections led to the development of a capacity prediction model forthese columns. In this model the compressive cross-sectional strength of the
PEC column is calculated using the following expression proposed byTremblay et al. (1998), with modifications from the work of Chicoine et al.
(2002):(

C r = A se F y + 0.92ψA c f cu + A r Fyr)(1)

where Ase is the effective area of the steel shape as defined by Equation (2),
Fy is the yield strength of the steel plate, Ac is the cross-sectional area ofconcrete, fcu is the concrete cylinder strength and Ar and Fyr are the area andyield strength of the longitudinal rebars.
A se = (d − 2t + 2b e )t(2)

where d is the overall depth of the cross-section, t is the thickness of thesteel plates and be is the total effective width of the flange. To account for
the effect of local buckling in the column capacity, be is expressed as:

bf

be =

≤ bf

(1 + λ )b 12(1 −ν )Fλ =
2n 1 n

(3)

p

2

s

p

k=

(4)

π Es kt

0.9(s b f )y2

2+ 0.2(s b f )2 + 0.75,(0.5 ≤ s b f ≤ 1) (5)In Equation (3), bf is the full width of a flange plate and λp is aslenderness parameter calculated using Equation (4). Es and νs in
Equation (4) are the elastic modulus and Poisson's ratio, respectively, of134

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

steel. The value of the factor n in Equation (3) is taken as 1.5, as proposedby Chicoine et al (2002).
Equations (1) to (4) are included in CSA S16-01 (CSA 2001) for
determining the design capacity of axially loaded PEC columns with builtup thin-walled shapes, but with a slight modification in the concrete strength
reduction factor. For simplicity, the strength reduction factor 0.92ψ inEquation (1) was replaced by 0.8 in CSA S16–01. However, these design
equations are subjected to certain limitations imposed by the scope of theexperimental and numerical research works. The yield strength of the steel
plate and reinforcing bars is limited to no greater than 350 MPa and
400 MPa, respectively, and concrete strengths only up to 40 MPa areallowed (normal density). The flange width, bf , must be within 0.9 to 1.1
times the section depth, d, and have a slenderness ratio, bf/2t, not greaterthan 32. The thickness of the web plate must be equal to the thickness of theflanges and the connections between them must be provided by continuous
fillet welds designed to develop the shear yield capacity of the web. The
spacing of the transverse links is limited to the lesser of 500 mm or 0.67d
and the area of a link must be at least the greatest of 63 mm2, 0.01bft and
0.5 mm2 per mm of link spacing. Finally, the equations are applicable only
to concentrically loaded columns with a clear height-to-depth ratio less than
14. As reported by Prickett and Driver (2006), the design equations forconcentrically loaded columns provide conservative estimations of the axial
capacity of PEC columns with high strength concrete. Therefore, it wasrecommended that the current upper limit for the strength of concrete beincreased from 40 to 70 MPa.
4.2

Columns under Combined Axial and Flexural Loading

Bouchereau and Toupin (2002) and Prickett and Driver (2006)
predicted the capacity of eccentrically loaded columns from load–momentinteraction diagrams constructed using a procedure commonly adopted forreinforced concrete columns. A linear strain distribution along the crosssection, based on observations from the strain measurements taken during
the test, was implemented for the construction of this diagram. The extreme
compressive strain was set at 3500 με, whereas the extreme tensile strain
was varied from 0 to 10 times the yield strain of the steel. For each strain
gradient the ultimate load and moment capacities were calculated from thematerial and geometric properties of the composite cross-section. To
calculate the contribution of the steel to the capacity of the composite
column, the section was discretised in such a way as to have effectively
uniform strain in each individual piece. For strong axis bending, the flanges
were considered to be one piece, whereas the web was divided into tenpieces. On the other hand, for weak axis bending the web was considered as
one piece and each flange was discretised into ten pieces (Prickett andDriver 2006).

Partially Encased Composite Columns: An Innovative Composite Structural System

135

December 2007, Dhaka, Bangladesh

5. CONCLUSIONS

The research on PEC columns with thin-walled sections reviewed in thispaper reveals that the behaviour of this composite system with normal andhigh performance materials have become relatively well understood fromthe full scale experimental investigations for monotonic concentric andeccentric axial loads. The finite element model developed for this newcomposite system can adequately represent the local buckling behaviour, theultimate load and the post-peak residual capacity for axial compression andbending. In addition, the influences of several key parameters, which could
not be covered by the experimental programs, on the behaviour of thesecolumns under axial compression and bending, were investigated using thefinite element model. However, the behaviour of this composite system
under cyclic loading has not been completely explored. Intensive research istherefore required to address the effects of cyclic bending moment on PEC
columns with variable geometric and material properties. And therefore, theexisting design guidelines for thin walled PEC columns should be extended
to cover the full range of behaviour of this innovative composite system
under various conditions of loading.

REFERENCES

Begum, M., Driver, R. G. and Elwi, A. E., 2007. Numerical Simulations of
the Behaviour of Partially Encased Composite Columns. StructuralEngineering Report, University of Alberta, Edmonton, Canada.
Bouchereau, R., and Toupin, J.-D., 2003. Étude du Comportement en
Compression-Flexion des Poteaux Mixtes Partiellement Enrobés.
Report EPM/GCS-2003-03, Ecole Polytechnique, Montreal, Canada
Chicoine, T., Tremblay, R., Massicotte, B., Yalcin, M., Ricles, J., and Lu,
L.-W., 2000. “Test Programme on Partially-Encased Built Up ThreePlate Composite Columns.” Joint Report EPM/GCS No. 00-06,
February, Dept. of Civil, Geological and Mining Engineering, Ecole
Polytechnique, Montreal, Canada – ATLSS Engineering ResearchCentre, No. 00-04, Lehigh University, Bethlehem, Pennsylvania, USA.
Chicoine, T., Tremblay, R. and Massicotte, B., 2002. Finite Element
Modelling and Design of Partially Encased Composite Columns. Steeland Composite Structures, 2 (3), 171–194.
CSA., 2001. CSA S16-01, Limit States Design of Steel Structures. CanadianStandards Association, Toronto, ON.
Filion, I., 1998. Étude Expérimentale des Poteaux Mixtes Avec Sectiond’acier declasse 4, Report no. EPM/GCS-1998-06, Ecole
Polytechnique, Montreal, Canada.
HKS (Hibbitt, Karlsson and Sorensen, Inc.), 2003. ABAQUS/Explicit User’s
Manual, Version 6.3.
Maranda, R. (1998) ″Analyses par Éléments Finis de Poteaux Mixtes Avec
Sections d’acier En I de Classe 4” Report no. EPM/GCS-1998-11,
Ecole Polytechnique, Montreal, Canada.
Prickett, B. S. and Driver, R. G., 2006. “Behaviour of Partially Encased
Composite Columns Made with High Performance Concrete.”136

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

Structural Engineering Report No 262, University of Alberta, AB,
Canada.
Tremblay, R., Massicotte, B., Filion, I., and Maranda, R., 1998.
Experimental Study on the Behaviour of Partially Encased Composite
Columns Made with Light Welded H Steel Shapes under Compressive
Axial Loads. Proc., SSRC Annual Technical Session & Meeting,Atlanta.

Partially Encased Composite Columns: An Innovative Composite Structural System

137

December 2007, Dhaka, Bangladesh

138

New Technologies for Urban Safety of Mega Cities in Asia

A STUDY ON EFFECTOF LAND-USE CONTROL PLAN
ALONG ACTIVE FAULTS IN JAPANMIHO YOSHIMURA OHARA
International Center for Urban Safety Engineering
Institute of Industrial Scnence, The University of Tokyo, Japanyosimura@iis.u-tokyo.ac.jp
KIMIRO MEGURO
International Center for Urban Safety Engineering
Institute of Industrial Scnence, The University of Tokyo, Japanmeguro@iis.u-tokyo.ac.jp
ABSTRACTJapan entered a longstanding depopulation process in 2006. In thissituation, it is important to avoid social impact due to disasters by guiding
population from vulnerable area to safer area. This research focused therisk of active faults among various kinds of natural hazards and studied on
the effect of the land-use control along active faults in Japan.
First, the meaning of land-use control plan along active faults in thesociety whose population started to decrease was discussed. If theresidences in the seismic vulnerable area along active faults are relocatedto the safer area by the land-use control plan, these vacant lands could be
effectively used for disaster-prevention facilities. Japan has not adopted
earthquake fault zoning act due to several reasons. However, considering
depopulation, the possibility of introducing fault zoning act will increase
and the discussion on the land-use control plan along active faults will
become more meaningful.
Then, the distribution of population and buildings in the neighborhoodof the active faults was analyzed based on GIS databases of the active faults,
population and building stocks. The effect of land-use control using fault
zones was discussed based on the obtained results. In case of the fault zone
whose width was decided to be 0.4km referring to the fault zoning act in
U.S., the population inside the fault zone was 2.89 million and it
corresponded to 2.3% of the total population in Japan. Half of the
population living along the faults was located in Kinki area and the effect ofland-use control was different according to the region. The population
inside the fault zone was increased in population to the width of the zone.

1. INTRODUCTION
Japan entered a longstanding depopulation process in 2006. According to
the report by the National Institute of Population and Social Security

139

December 2007, Dhaka, Bangladesh

Research (2002), the total population after 50 years is expected to decrease
to about 70% of the current one as shown in Fig.1. In this situation, it isimportant to avoid social impact due to disasters by guiding population fromvulnerable area to safer area. Recently, Japan suffered the 2004 Niigataken
Chuetsu Earthquake, the 2007 Noto Hanto Earthquake and the 2007
Niigataken Chuetsu-oki Earthquake. These earthquakes reminded a dangerof active faults in Japan. This research focused on the risk of active faults
among various kinds of natural hazards and studied on the effect of the landuse control along active faults in Japan. First, the meaning of land-use
control plan along active faults in the society whose population started todecrease was discussed. Then, the distribution of population and buildingsin the neighborhood of the active faults was analyzed based on GIS
databases of the active faults, population and building stocks. The effect ofland-use control using fault zones was discussed based on the obtained
results.

Figure 1: Population projections for Japan:2001-2050

2. MEANINGFAULTSOF

LAND-USECONTROLALONG

ACTIVE

When the total population decreases, existing building stocks become
unnecessary, and the numbers of vacant houses and lands increase. If theresidences in the seismic vulnerable area along active faults are relocated tothe safer area by the land-use control plan, these vacant lands could be
effectively used for disaster-prevention facilities which have open space andwarehouses for emergency supplies. These processes were illustrated in
Figure 2.

140

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ICUS Report 27

Open
space

Active fault

Active fault

Active fault

1. Increase of
vacant lands

2. Relocation tosafer area

3. Open Space
along the fault

Figure 2: Process of land-use control
Table 1: Conceivable policies for controlling land use
Direct Policy
Indirect Policy
Regulation of new construction* Increase in tax for new construction
Prohibition of new construction Increase in property tax for existing buildings
Repression ofDisclosure of seismic risk information on property sales
population inflow
Disclosure of seismic risk information on prental agreement*
Publicity of sesmic risk information*
Relocation of existing buildings grant for relocation
Regulation of extension orPreferential tax treatment for relocation
reconstruction of buildings*
Promotion ofProhibition of extension or
population
Increase in property tax for existing buildings
reconstruction of buildings
outflow
Regulation of rental agreement Disclosure of seismic risk information on property sales
Prohibition of rental agreement Disclosure of seismic risk information on prental agreement*
Publicity of sesmic risk information*

Table 1 shows the conceivable policies for controlling land use. The
lands along active faults could be controlled by the repression of the
population inflow and the promotion of the population outflow. These could
be achieved by direct method such as prohibition and regulation of land use
or by indirect method such as disclosure of seismic risk information and tax
control. The policies marked with * in the Table 1 are being enforced in
California, U.S. by the Alquist-Priolo Earthquake Fault Zoning Act enacted
in 1972
While the earthquake fault zoning act has been carried out for 30 years
in U.S., Japan has not adopted it. There are several reasons why most of theJapanese specialists have opposed fault zoning. First, introduction of thefault zoning could have huge social impact because Japanese population
density is high and a lot of people live on the active faults. Next, most of theactive faults in Japan are dip-slip faults and there are many cases that tracesof the faults don’t appear on the surface. Even if the traces on the surface
are estimated, uncertainty of the position should be considered. On the other
hand, active faults in California, U.S. are strike-slip faults and traces on thesurface are easier to be identified. However, considering that more lands
will become vacant due to depopulation in the future, the possibility of
introducing fault zoning act will increase and the discussion on the land-use
control plan along active faults will be more meaningful.

A Study on Effect of Land-Use Control Plan Along Active Faults in Japan141

December 2007, Dhaka, Bangladesh

3. DISTRIBUTION OF ACTIVE FAULTS IN JAPANFirst, GIS database of the active faults were developed by adding several
data to the existing digital active fault map (2002). The total length of active
faults in Japan is about 10,300 km. When the lengths of active faults wereclassified by the fault types, 34% of the active faults were dip-slip and 4%
were strike-slip as shown in Fig. 3. “Mixed ” in Fig. 3 means the fault thathas both strike-slip part and dip-slip part. In case of “Mixed Ⅰ”, the rate of
the length of dip-slip part is more than 70%. In case of “Mixed Ⅱ”, the rateof dip-slip part is between 30% and 70%. Figure 3 shows the distribution ofactive faults in Japan.

3030
29%

3558
34%

Total length:
断層長[Km]
10,300km
約10300Km

406
4%
938
9% 752
7%

1645
16%

Dip-slip fault
Mixed Ⅰ
Mixed Ⅱ
Mixed Ⅲ
Strike-slip fault
Unknown

Figure 3: Composition of active fault types
Hokkaido
Dip-slip fault
TohokuKoshinetsu

Mixed Ⅰ
Mixed Ⅱ
Mixed Ⅲ
Strike-slip fault
Unknown

Hokuriku

Inhabited area

Cyugoku
Kanto

Kinki
Shikoku
KyosyuFigure 4: Distribution of active faults in Japan142

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ICUS Report 27

4. ESTIMATION OF THE EFFECT OF LAND=USE CONTROLALONG ACTIVE FAULTS
The distribution of population and buildings in the neighborhood of theactive faults was analyzed using GIS databases of the active faults,
population and building stocks. Then, the effect of land-use control using
fault zones was discussed.
The GIS databases of population and building stocks were developed
based on the 1km mesh data by Housing and Land Survey (1998). The fault
zones were hypothetically set along the active faults as shown in Fig. 5. In
California, average width of fault zones is reported to be 0.4km. Referring
to it, the width of the fault zone was set to be 0.4km at first. In case of thiswidth of zone, the population inside the fault zone was 2.89 million and it
corresponded to 2.3% of the total population in Japan. 0.62 million timberresidential houses were estimated to be located inside the zone. Although
4% of the active faults were strike-slip as shown in Fig. 3, the rate of the
population living along the strike-slip faults were only 0.4% as shown in Fig.
6. Figure 7 describes the regional tendency of population distribution along
the active faults. Half of the population living along the faults was locatedin Kinki area while 40% of the faults were located in Hokkaido-Tohoku or
Hokuriku-Koshinetsu Area. It is said that the effect and the impact of landuse control are different according to the region.
If the width of the fault zone was increased to be 0.8km, 2km, 4km,
the population inside the zones was estimated to be 4.5%, 10%, 18% of thetotal population, respectively. Increase in population was almost in
proportion to the width of the fault zones.
Considering the uncertainty of the traces of active faults, larger fault
zones are safer. However, it causes more social impact on the population
living along the active faults as confirmed in Fig. 8. In order to implement
land-use control along active faults in Japan, the appropriate width of fault
zones should be discussed considering all the factors such as lessons learned
from past earthquake damage, uncertainty of the traces of both strike-slip
and dip-slip fault, social impact of the zones.

Active fault
Fault zone
1km Mesh

Figure 5: Example of fault zone

A Study on Effect of Land-Use Control Plan Along Active Faults in Japan143

December 2007, Dhaka, Bangladesh

44532015%1206414
12853
43%
0.4%
196438
人口[人]Population:
7%
2.89million
約289.3万人
2.3% of total
人口の2.3％44796415%583630
20%

96546
16%
254480
3725
41%
0.6%
50567 Timber
木造建物[棟]
house:
8%
0.62million
約62.0万棟
2.2% of total
建物の2.2％83530
13%13027721%

Dip-slip fault

Mixed Ⅲ

Mixed Ⅰ
Mixed Ⅱ

Strike-slip fault
Unknown

Figure 6: Population and buildings inside the fault zone
21640229214 7% 265882
0.6%
9%
86988
242365
3%
8%

Population:
人口[人]31506411%
2.89million
約289.3万人
2.3%
of total
人口の2.3％32879511%140791050%

Hokkaido, Tohoku
Kanto
Hokuriku, Koshinetsu
Tokai

Kinki
Cyugoku
Shikoku
KyusyuFigure 7: Regional tendency of population distribution
94325317%25898
1%358823
6%

2366805
43%

0.8Km
Population:
約564.0万人
5.64million
人口の4.5%of total
851304 4.5%
15%109386719%263913220%5488085
42%

67469
1%
Population:
2Km
719865 約1289.0万人
12.89million
6%10%
人口の10%of total

162054413%235445018%593197826%

9676016
41%

4Km
Population:
1468081%
約2321.8万人
23.22million
1174090 人口の18%
18% of total
5%235872210%393088617%

Dip-slip fault
Mixed Ⅰ
Mixed Ⅱ
Mixed Ⅲ
Strike-slip fault
Unknown

Figure 8: Population inside the fault zone when the width of zone ischanged144

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

5. CONCLUSIONSJapan entered a longstanding depopulation process in 2006. In this situation,
it is important to avoid social impact due to the disaster by guiding
population from vulnerable area to safer area. This research focused the riskof active faults among various kinds of natural hazards and studied on theeffect of the land-use control along active faults in Japan.
First, the meaning of land-use control plan along active faults in thesociety whose population started to decrease was discussed. While fault
zoning act has been carried out for 30 years in U.S., Japan has not adopted it
due to several reasons. However, considering that more lands will become
vacant due to depopulation in the future, the possibility of introducing fault
zoning act will increase and the discussion on the land-use control plan
along active faults will become more meaningful.
Then, the distribution of population and buildings in the neighborhoodof the active faults was analyzed based on GIS databases of the active faults,
population and building stocks. In case of the fault zone whose width was
assumed to be 0.4km referring to the act in U.S., the population inside thefault zone was 2.89 million and it corresponded to 2.3% of the total
population in Japan. Half of the population living along the faults was
located in Kinki area and the effect and the social impact of land-use control
was different according to the region. The population inside the fault zone
was increased in population to the width of the zone. The appropriate widthof fault zones should be discussed considering all the factors such as lessons
leaned from past earthquake damage, uncertainty of the traces of bothstrike-slip and dip-slip fault, social impact of the zones.
Based on the study, the authors think that it is meaningful and possible
to adopt land-use control plan along active faults in Japan for earthquake
damage reduction. However, for its implementation, a study on social
impact of the risk information of active faults is necessary to decide proper
width of the fault zone and to get social consensus.

REFERENCES
Schumm, S. A., Mosley, M. P., and Weaver, W. E., 1987. Experimental
geomorphology: the Study of Small Landforms. John Wiley, NewYork.
The National Institute of Population and Social Security Research, 2002.
Population Projections for Japan:2001-2050,
http://www.ipss.go.jp/index-e.html.
California Geological Survey, 2007. Alquist Priolo Earthquake Fault Zones,
http://www.consrv.ca.gov/CGS/rghm/ap/index.htm.
Nakata T. and Imaizumi T., 2002. Digital Active Fault Map of Japan,
University of Tokyo Press.
Statistics Bureau, Ministry of Internal Affairs and Communications, 1998.
Housing and Land Survey

A Study on Effect of Land-Use Control Plan Along Active Faults in Japan

145

December 2007, Dhaka, Bangladesh

146

New Technologies for Urban Safety of Mega Cities in AsiaAPPLICATION OF GEOPHYSICAL IMAGING IN SUBSURFACE CHARACTERIZATIONFOR URBAN SAFETY IN AN EARTHQUAK
E - A CASE STUDY FROM DHAKAMEGA CITY, BANGLADESH
AFTAB ALAM KHAN
Professor, Department of Geology
University of Dhaka, Dhaka, Bangladesh
TUaftab@univdhaka.eduUT
MUHAMMAD SHAHADAT HOSSAIN
Graduate Research Assistant
Department of Geology and Geography
Auburn University, USA

ABSTRACT
Dhaka, capital of Bangladesh is one of the fastest growing
megacities with its present population exceeding 14 million. It is situated in
the periphery of the southern fringe of tectonically uplifted Madhupur
Pleistocene Terrace bounded by both En échelon and cross faults. The
recent earthquake activities and other geophysical evidences suggest that
Dhaka and surroundings is geologically active. The existence of Buriganga- Dhaleshwari fault and the dominancy of mud, clay and swampy deposits
propelled its vulnerability to earthquake damage to the settlements and to
infrastructures. The distribution pattern of both P- and S- wave suggest thatthe top layer is largely transverse to the distribution pattern of the layer
below. The zones with high seismic velocity are characterized by low
particle velocity and vice versa. Hence, the zones characterized by highparticle velocity (low shear wave velocity) are considered as damage
vulnerable zones. The seismic velocity has also been used to determine theresonant height of buildings at various locations. The Vertical ElectricalSounding (VES) rendered the distribution pattern of the sediments upto a
depth of 240 meter. Sediments with high resistivity value / low fluid
saturation cover the central and northern part of Dhaka. In the central part,clay is dominant, truncating against sand dominated zone in thesouthwestern part. In the northeastern part, sand increases with depth andthe layers are much more continuous in nature than in the northwestern
part. The 2–D imaging / Constant Separation Traversing (CST) reveal thelithological discontinuities, buried channels, regional tilting, and saturated– unsaturated fills upto a depth of 125 meter. Vertical Electrical Sounding(VES) and Electrical Tomography in combination has enabled to identify
several faults such as Singair fault, Buriganga-Dhaleshwari fault, Nayarhat
fault, and Tongi-Turag fault those occur in and around Dhaka. The
simulated lithologic models depict the variations in lithology up to 174147

December 2007, Dhaka, Bangladesh

meter depth. A generalized stratigraphic model exhibits three distinct
stratigraphic unit e.g. Top clay, Sand, and Clay. The lithologic data exhibits
the presence of a north–south trending fault in between Tejgaon and Bananiin the north and in the south in the midst of BUET, DU campus andPhulbaria eventually merging with Buriganga fault.
An integrated approach has been adopted to prepare an earthquake
hazard vulnerability map based on the identification of faults, subsurface
lithological variations, velocity characterization, and dominant frequency
response and “g” value character. Geophysical data can immensely
contribute in urban risk management and effective disaster management
plan and program to mitigate damage from possible earthquakes.

1. INTRODUCTION
Dhaka with an area of 815.85 sq. km. and about 14 million populations is
the capital of Bangladesh. Dhaka urban area covers the spatial zone between
the latitudes 23° 41' N and 23° 55' N and longitudes 90° 20' E and 90° 31' E.
In a study on 20 mega cities of the world, Dhaka appeared to have one of
the highest values of Earthquake Disaster Risk Index (EDRI) mainly due toits inherent vulnerability of building infrastructure, high population density,
poor emergency response, and poor recovery capability. Any physicalphenomenon associated with an earthquake that may produce adverse
effects on human activities is termed as earthquake hazard. This includes
surface faulting, ground shaking, landslides, liquefaction, tectonic
deformation, tsunami, and their effects on land use, fabricated structures,and socio-economic systems. A commonly used restricted definition ofearthquake hazard is the probability of occurrence of a specified level ofground shaking in a specified period. Similarly, earthquake risk is the
expected (or probable) life loss, injury, or building damage that will happen,
given the probability that earthquake hazard occurs. The recent earthquake
activities and other geophysical evidences suggest that Dhaka andsurroundings is geologically active (Khan, 2005).
Geophysical imaging pertaining to electrical resistivity and seismic
velocity has been obtained for subsurface characterization of Dhaka city.
Imaging by Vertical Electrical Sounding (VES) is used to decipher verticallithological changes and character while, imaging by Constant Separation
Traversing (CST) is used to decipher lateral lithological changes with fluid
saturation status, buried channels, filled zones, faults and discontinuities.
Cross checking on to the variations in lithology both in vertical and lateraldimensions have been performed through preparing 3D panel diagram ofavailable drill-holes of Dhaka WASA and other agencies, and observing
available geophysical well-log response. Twenty (20) borehole litho-logs ofDhaka WASA and Sixteen (16) Geophysical Well Logs were used tosimulate the subsurface for cross checking. The geophysical images are ingood agreement with 3D panel diagram and well-log response. The acquired
seismic velocities are used to determine acceleration due to gravity (g) andresonant height of the building through dominant frequency response.

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2. GEOMORPHOLOGY AND GEOLOGY
Dhaka Metropolis is surrounded by Buriganga River, a channel of
Dhaleshwari River in the south; rivers Balu and Shitalakhya in the east;
Tongi Khal in the north and the river Turag in the west. It occupies mostly
by the southern fringe of Madhupur tract. Elevation map of Dhaka city
generated by DWASA elevation data shows that the elevation of the entire
eastern Dhaka ranges between 3 to 4.5m. A large part of the north-south
trending central region bears the elevation between 5 and 8m with a regional
gradient towards north. The southern part of the north-south trending central
region covering part of Ramna, Tejgaon, Hazaribagh, Mohammadpur, andMotijheel Thanas exhibits the elevation between 9-10m. The elevation of asmall segment of area at Mirpur-Pallabi reaches upto 13.5m above mean sea
level. The elevation distribution of Dhaka city signifies a northward tilt of
the north-south trending uplifted central region. There are distinct
subsurface gradient towards east, west and south suggesting a radial anddivergent gradient pattern.
Most parts of the urban areas are developed on the elevatedPleistocene highlands. However, a substantial portion of the adjoining lowlying areas has recently been brought under the accelerated rate of urban
growth. Geologically, Dhaka is situated at the southern tip of Madhupur
High (Pleistocene Terrace) surrounded by subsiding floodplains. The
tectonics and its structural configuration largely control the sedimentationand stratigraphy of the area. Two characteristic geologic units cover the cityand surroundings, viz. Madhupur clay of the Pleistocene age and Holocene Recent alluvial deposits. The Madhupur clay is the oldest sediment exposedin and around the investigated area having characteristic topography anddrainage. The differential elevation, landform and distribution of geologic
units those are visualized in the landsat image terminated into a corrugatedtopography. A north-south trending prominent buried channel dissecting
Dhaka-Savar main uplands has been identified. The surface manifestationsof elevation helped to identify some prominent faults in and around Dhaka
city such as Nayarhat fault, Dhaleshwari fault, Buriganga fault, and TongiTurag fault (Figure 1). The NE – SW trending geologic cross-section (Fig.1)
exhibits a general subsurface configuration characterizing uplifted
Pleistocene terrace, depressed lands, flood-plains and abandon channels(Khandoker, 1987).

3. DATA ACQUISITION AND ANALYSIS
Extensive field investigations were performed covering the entire Dhaka
metropolitan area for data acquisition and generation pertaining toearthquake-hazard vulnerability assessment. Shallow subsurface data wereobtained applying both Vertical Electrical Sounding (VES) and Constant
Separation Traversing (CST) of geophysical technique of electrode array.
Thirteen Vertical Electrical Sounding (VES) and five 2–D profiling by
Constant Separation Traversing (CST) were carried out. Seismic velocity

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survey was conducted with the help of hammer seismograph for
determining shallow subsurface seismic velocity variations.
Seismic refraction techniques were used to obtain data on the nearsurface (typically to about 30 meters, although depths in excess of 200
meters can be achieved with more powerful seismic sources). The velocity
measurement at Twenty-Two locations in Dhaka city has provided P-wave
velocity both for top layer (Vp0) and for the layer below (Vp1). The P-wave
velocity was transformed to S-wave velocity assigning suitable Poisson’s
ratio value derived from the material type (clay to sand) occurring at thevelocity measuring site. Velocity data has also been used to determine theresonant height of the building at various locations.

Figure 1: Geomorphic image and NE-SW cross-section of Dhaka
metropolitan city showing various geomorphic features and faults.
The optimal length required for resonance has been calculated from theshear-wave velocity data. Hence, the optimal number of floors that is likely
to coincide with the ground resonance has been calculated assuming 10 feet
floor height. The notion of acceleration due to gravity (g) is of key
importance when trying to measure any type of varying motion such as
strong ground shaking. An attempt has been made to calculate theacceleration due to gravity (g) based on the shear wave velocity of the top
layer, background frequency of the ground and ground displacement at all
the twenty-two locations of velocity measurements.
Borehole logs are the records of vertical lithologic rock units of aparticular place. Twenty (20) borehole logs were treated in 3D environment
using RockWorks2004®. The selection was based on prior consideration
upon the coherence and consistency of the information and even distributionof logs throughout the area. The layering information on the sand and clay
horizons has been used in the lithologic model reconstruction. Geophysicallogs give much more detailed picture of the subsurface and are expensive as
well. Resistivity depends on the porosity and nature of the interstitial fluid.

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It is seen that resistivity increases logarithmically when porosity decreases.
Normally, the sand is more resistive than clay. Sand layer containing fresh
water is more resistive than salt water. One test hole in the University of
Dhaka campus has been logged for natural gamma and induction EM
conductivity up to a depth of 270 meters. Number of geophysical resistivity
logs available with DWASA was used to identify sand and clay horizons forstratigraphic reconstruction.

4. RESULTS AND INTERPRETATIONElectrical Sounding
Vertical Electrical Sounding (VES) data acquired for determination of
number of layers with thickness and resistivity of each layer. In general,
resistivity changes with the fluid saturation while, fluid saturation depends
on pore volume and its interconnection. Normally, greater the porosity
percentage and fluid saturation lesser is the resistivity and vice versa.
Vertical electrical sounding data have been used to generate dominant
lithological logs by using inverse modeling technique (Figure 2).

Figure 2: Vertical Electrical Soundings (VES) generating dominant
lithological logs and 3D lithological perspectives.
The Dhaka metropolitan city area is characterized by dominantly
clay upto 240m depth with intermittent sand. The surface is covered by bothsand and clay. The northern and central part is mostly covered by sandwhile in the southern part and some parts in the northeast and northwest iscovered by clay. The average thickness of the top clay ranges from 3 to 10m
and in some places (VES 10), it reaches upto 24m. This clay unit is thicker
in the middle part of Dhaka metropolitan city area. The thickness of this unit
gradually decreases towards southeastern part of the studied area while in
the other places it is more or less similar in thickness. Correlation between
VES07 and borehole litholog at Mirpur DOHS reveal a unique matching
between the vertical lithological change and VES response (Figure 3).
Based on electro-stratigraphy three sub-surface zones with distinct
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lithological character have been identified in the near surface viz., clay richzone, saturated sand rich zone, and partially saturated sand rich zone (Khanand Hossain, 2005).
Correlation of vertical imaging by VES revealed distinct offsets
between the layers signifying faults. The correlations have further identified
faults such as Turag-Tongi fault between VES 12 & VES 07, Dhaleshwari
fault between VES 30 & VES 25, and Buriganga fault between VES 25 &VES 22 with off-sets approximately 19m, 16m, and 18m respectively(Figure 4).

Figure 3: Correlation of VES with Borehole log at DOHS, Mirpur.

Figure 4: Correlation of Vertical Electrical Soundings (VES) showing
several fault offsets.

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Electrical Profiling
Subsurface correlation based on lateral imaging (Fig. 5) covering 125m
depth by profiling suggests that the lateral distribution of lithology is of
distinct truncating nature providing evidences of tilting, faulting, incisedchanneling, and fills with variable saturation status. The high resistive drylayer characterizes the zones of uplift and tilting. While, low resistive layerswith greater saturation status characterize the zones of subsidence and fills.
The northern block of Tongi fault is an uplifted one but tilted towards south.

Figure 5: Subsurface correlation by lateral imaging shows lateral
distribution of lithology, evidence of tilting, faulting, incised channeling,
and fills with variable saturation status.
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Although, Narayanganj area has been identified as an uplifted andtilted block but due to paucity of data the effects of Buriganga fault on thereadjustment of subsurface status could not be identified. Nonetheless, theBuriganga fault is a basement-controlled fault that is genetically related withthe uplift of Madhupur High and the subsidence of Jamuna depression(Khan, et al., 2000).
Bore-hole Geophysics
Bore-hole resistivity logs along a north-south transect across Mirpur,
Banani, Rajarbagh and Jurain of Dhaka city exhibits subsidence and fills inthe southern part (Jurain – Syedabad area), intense channeling and fills in
the central part (Rajarbagh – Motijheel area), and uplift in the northern part
(Banani – Mirpur area) (Fig. 6). It is further envisaged that an offset
between uplift and subsidence occurs to the tune of about 10m exhibiting
traces of Begunbari and Buriganga faults.

Figure 6: Bore-hole resistivity logs along a north-south transect acrossMirpur, Banani, Rajarbagh and Jurain of Dhaka city exhibiting subsidence,
fills, channeling and uplift.
Seismic Velocity
The shallow seismic velocity measurements at Twenty-Two locations
within Dhaka city have provided P-wave velocity both for top layer (Vp0)and the 1PstP layer (Vp1) (Fig. 7). P-wave velocity has been transformed toshear wave (S-wave) velocity using Poisson’s ratio adopted on the types ofmaterials occur at each measuring site (Fig. 8). The seismic velocity maps
envisage the lateral changes in both the layers. The velocity contour maps
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P-wave and for S-wave suggest that the distribution pattern of the top
layer is largely transverse to the distribution of the bottom layer. The
transverse nature of velocity distribution suggests that the sediments of the
1PstP layer have been deposited mostly in the east-west trending depositional
floor while the top layer sediments have been deposited mostly in the northsouth trending depositional floor.

Figure 7: Shallow seismic P-wave velocity distribution of Dhaka
metropolitan city both for top layer (Vp0) and for the 1PstP layer (Vp1).

Figure 8: Shallow seismic S-wave velocity distribution of Dhaka
metropolitan city both for top layer (Vs0) and for the 1PstP layer (Vs1).

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The shifting nature of the depositional floor is an indication of theshifting of the transporting and depositing media. Such shifting can occur
with the change in the physical configuration of the depositional floor.
Hence, it is inferred that the region in and around Dhaka mega-city had beengeologically active in the recent time. The high seismic velocity zones arecharacterized by low particle velocity and vise-versa. Hence, the zones
characterized by the low shear wave velocity are inferred to be the high-riskzones of seismic hazard.
Resonance
Seismic velocity data of the study area have been used to determine
the dominant frequency content (resonant length) at various locations of
Dhaka city (Fig. 9). The map shows dominant frequency content ranging
between 0.6 and 0.9 hertz.

Figure 9: Dominant frequency content (resonant length) distribution of
Dhaka metropolitan city.
Considering the default floor height as 10ft, the optimal heightrequired for multi-mode resonance has been calculated from the shear-wave

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velocity. The optimal number of floors that is likely to coincide with theground resonance is shown (Figure 10).

Figure 10: Optimal number of floor requirements for resonance in Dhaka
metropolitan city.
Ground Acceleration (g)The notion of acceleration due to gravity (g) is of key factor when trying
to measure any type of vibrating motion such as strong ground shaking. The
acceleration due to gravity (1g = 9.8 m/secP2P) is a sizable rate of increaseof speed, which is equivalent to a car going 100m from rest in just 4.5
seconds (Bolt, 1978).
The values of ground acceleration, velocity, and displacement vary agreat deal, depending on the frequency of the seismic wave motion of anearthquake. The relations of ground displacement, ground velocity, andground acceleration are explained in the following mathematical treatment.
For a traveling simple harmonic wave, the ground displacement ‘y’ at agiven time‘t’ is a function of position ‘x’ and time ‘t’.
y = A sin 2π/λ (x + vt)
Here, A is Amplitude, λ is Wavelength, and v is Velocity.
In time T, called the period, the wave travels a distance ‘λ’ is the timeof a complete vibration.
The velocity of the wave is the wavelength divided by the period.
Hence, v = λ/T = f λ, where f is the frequency in Hz.
The angular frequency ω =2 π fThus, the sideway motion can be written as
Ground displacement = y = A sin (2π/T) t = A sin ωt
Ground Velocity = ý = 2πA/T cos (2π/T) t = ωA cos ωtGround Acceleration = ÿ = - 4π2A/T2 sin (2π/T) t = - ω2 A sin ωt = ω2y
An attempt has been made to calculate the acceleration due to gravity(g) based on the shear wave velocity of the top layer, background frequencyof the ground and ground displacement at all the twenty-two locations ofApplication of Geophysical Imaging in Subsurface Characterization for Urban Safety in an Earthquake - A Case
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velocity measurement. It is found that the peak ground acceleration (PGA)
ranges between 0.26g to 0.49g distributed within Dhaka Metropolis(Figure 11).

Figure 11: Peak Ground Acceleration (PGA) distribution of Dhaka
metropolitan city.
Based on the lithological variations, velocity characterization,
dominant frequency response, and ‘g’ value character, an earthquake
damage vulnerability map of Dhaka city has been proposed (Fig. 12)
dividing into three zones viz., High vulnerable, Intermediate vulnerable, andLow vulnerable respectively.

Figure 12: Earthquake damage vulnerable zones of Dhaka metropolitan city.

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5. CONCLUSIONS AND RECOMMENDATIONS
Various geophysical techniques including shallow seismic velocity,
resistivity CST, vertical electrical sounding (VES), borehole resistivity log,
and litholog analysis are used to characterize the subsurface and to identify
the earthquake hazard vulnerable zones in the Dhaka Metropolis. Electricalresistivity techniques (VES and CST) and the litholog correlation haveenabled to infer near surface lithological variations. The eastern region
covering Uttar Khan, Badda, Baridhara and Demra is characterized bydominantly clay and filled materials while the western region covering partof Mirpur, Mohammadpur, Shyamoli, Kallayanpur, Rayer Bazar, Pilkana,Hazaribagh is characterized by dominantly sand with considerable filledmaterials in the subsided near surface zones. The northern and central part ismostly covered by sand while in the southern part is covered by clay.
Resistivity logs suggest that the central part of the investigated area is much
more resistive than the eastern and western part of Dhaka metropolitan city.
Subsurface correlation by profiling provides the evidences of lateral
distribution pattern of lithology, tilting, faulting, incised channeling, andfills with variable saturation status. The high resistive layers characterize
relatively dry zones of uplift and tilting. While, low resistive layers withgreater saturation status characterize the zones of subsidence and both
artificial and natural fills. VES, CST, and borehole resistivity in
combination suggest subsidence and fills in the eastern and southern part,
intense channeling and fills in the central part, and uplift in the northern andcentral part with several fault offsets viz., Turag-Tongi fault (19m),
Dhaleshwari fault (16m), and Buriganga fault (18m).
The lithological character of the top layer both at the eastern andwestern part of the city is dominated by mud, clay and swamp deposits
characterizing low shear-wave velocity and high particle velocity. The low
ground frequency character both for eastern and western part of the city
coincide well with the low shear-wave velocity zones resulting in low
resonant length in these areas. Based on the subsurface lithologicalvariations, velocity characterization, dominant frequency response, and ‘g’value character, an earthquake hazard map of Dhaka city has been proposed
dividing into three zones of earthquake damage vulnerability viz., High,Intermediate, and Low vulnerable zones respectively.
The study warrants more detailed investigations for active-fault
identification and micro zoning.

REFERENCES
Bolt, B. A., 1978. Earthquakes- A Primer. W. H. Freeman and Company,
San Francisco. 241p.
Caputo, R., Piscitellib, S., Olivetoc, A., Rizzob, E., and Lapennab, V., 2003.
The use of electrical resistivity tomographies in active tectonics:
examples from the Tyrnavos Basin, Greece. Journal of Geodynamics,
Pergamon, v. 36, p. 19–35.

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Study from Dhaka Mega City, Bangladesh
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December 2007, Dhaka, Bangladesh

Herrick, D.C., and Kenedy, W. D., 1994. Electrical efficiency – a poregeometry theory for interpretating the electrical properties of reservoir
rocks. Geophysics, v. 59(6), p. 918-927.
Khan, A. A., Akhter, S. H., and Alam, S. M. M. 2000. Evidence of
Holocene transgression, dolomitization and the source of arsenic in
the Bengal delta, In: A.M.O. Mohamed & K. I. Al Hosani (Edts.),
Geoengineering in Arid Lands. Balkema Publication, Rotterdam, p.
351 – 355.
Khan, A. A. and Hossain, M. S., 2005. Recurrence of 1885 Bengal
Earthquake and hazard vulnerability status of Dhaka Metropolitan
City, Bangladesh. Oriental Geographer, v.49 (2), p.205-216.
Khan, A. A. 2005. Paleoseismicity, characterization of active faults andfault rupture recurrence in Bangladesh. Proc. 1PstP Bangladesh Earthq.
Symp., Bangladesh Earthquake Society, p. 63-70.
Khandoker, R. A., 1987. Orogin of Barind-Madhupur elevated areas, Bengal
basin-results of neotectonic activities. Bang. Jour. Geol., v.6, p.1-7.
Telford, W. M., Geldart, L. P., Sheriff, R. E., and Keys, D. A., 1976.
Applied Geophysics. Cambridge University Press, Cambridge. 860p.

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ESTIMATION OF RISK DUE TO
EARTHQUAKE HAZARD IN AP, INDIAAN IT BASED APPROACH
MD. ZIYA UR RAHMAN SIDDIQUI
Graduate Student
Computer Aided Structural Engineering
IIIT Hyderabad, India
Siddiqui@students.iiit.ac.in
RANJEET JOSHI1,
RAMANCHARLA PRADEEP KUMAR2
Earthquake Engineering Research Centre
IIIT Hyderabad
ABSTRACTThis paper describes the procedure of vulnerability assessment forbuilding structures in AP India. The objective of this paper is to define thebuilding classification and development of damage probability matrix usingfragility curve parameters of the building structures in Andhra Pradesh(AP) by using the available information in Vulnerability Atlas of India,
developed by Building Materials & Technology Promotion council Govt. ofIndia (BMTPC). The organization of this paper is as follows. First, the typesof the structures in AP are reviewed and a classification based on theavailable data with Vulnerability Atlas of India. Second, the description of
methodologies developed under various organizations is studied, adopted
and summarized. Third, the theoretical methodology of the vulnerability
analysis using fragility curves parameters given by HAZUS and capacity
curve generated using SAP2000 for typical building structure are presented.
Key words: HAZUS methodology, capacity curve, fragility curve,
damage probability matrix.
1. INTRODUCTION
India is always vulnerable to multiple hazards. Whether they areearthquakes, floods, cyclones or droughts, every year significant losses canbe observed in either of the forms. Andhra Pradesh lies in central part of thepeninsular Indian shield and long considered to be a seismically passive area,
But after the Jabalpur (1997), Latur (1993), and Koyna (1967) earthquakes
now its seismicity is questionable and few zones with reactivated faults inthe crustal layers of this region have been detected. Government of Andhra
Pradesh designed the Andhra Pradesh Hazard Mitigation (APHM) and
Emergency Cyclone Recovery Project (ECRP) under financial help fromWorld Bank to mitigate hazards, preparedness and to develop good161

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management and technical level mechanism for effective response inAndhra Pradesh.
1.1

Earthquake risk

Earthquake Risk gives an estimate of damage and loss due toearthquakes. Earthquake risk can be defined in terms of three prime factors
as given below:
Earthquake Risk = Vulnerability x Hazard x Exposure time(1)

Vulnerability is one of the main factor in defining risk and it isdefined as the degree to which a system is susceptible or unable to copewith adverse effect of climate change. It is more important to study andevaluate vulnerability of areas occupied by weak infrastructure system in ahighly seismically active area and find out expected damage losses during
earthquake. Vulnerability assessment of such seismically active area helps
local authorities in proper disaster management.
2. METHODOLOGY
There are several risk assessment tools proposed by different countries andorganizations like HAZUS (USA), TELES (Taiwan), RADIUS (UN) basedon inventory data and inputs through GIS engine to produce result fordifferent disaster. One of the major components of the methodology isextensive database. An inventory is made up of general building stock andgroups of building with specific characteristics. The main aim of making
inventory of building is for classification of building in different group withsimilar characteristics. The classification of building based on theconstruction type, material type, and structural type, buildings are classified
into five categories such as wood framing, steel framing, concrete framing,
reinforced concrete framing, and unreinforced concrete framing. These
structure frames are further classified to different structural classes based on
their material used and structural design. Figure 1 shows the methodologyof earthquake loss estimation adopted by HAZUS. This methodology is
divided in seven steps from input requirement to the development of
Damage Probability Matrix.
2) GROUNDMOTION &SEISMICDATA

3) RESPONSE
SPECTRA ATPERIOD OF 0.1
AND 0.3 SEC

6)5)PEAKCALCULATIONRESPONSE OFOF
MODEL
CUMULATIVEBUILDING
PROBABILITIES

4) CAPACITYCURVE , YIELDAND ULTIMATECAPACITY

1) MODEL
BUILDING
TYPE

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OF ALLDAMAGESTATE
7) DISCREETDAMAGE
8) DAMAGE
PROBABILITIESPROBABILITY
OF ALL
MATRIXDAMAGESTATES
Figure 1: flow diagram of HAZUS methodology
3. BUILDING CLASSIFICATION
Based on the available data with Vulnerability Atlas of India (VAI, BMTPC
Govt. of India) classification is developed and used in the development of
Damage probability Matrix for a particular model type. The classification isavailable with VAI is as follows:
Category-A: Buildings in fieldstone, rural structures, un-burnt brickhouses, clay houses
Category-B: ordinary brick buildings, building of the large block andprefabricated type, half-timbered structures, building in natural hewn stone.
Category-C: reinforced building, well built wooden structures
Category-X: other types not covered in A, B, C. these are generally
light
Buildings are classified based on structural characteristics like numberof stories, low-rise (1-3 stories), Mid-rise (4-7 stories) and High-rise(8+ stories) and material type: steel frame, concrete frame, brick masonryburned and unburned, stone masonry and mud wall. Figure 2 shows tow
types of buildings.
A total of 10 classes of buildings are defined in Table 1 below.
Table 1: classification based on material and storey height(Wen-I L, Chin-hsiung L 2006, HAZUS-MH 2003)

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Figure 2: (a) Example of RM (Mid-Rise) and (b) is an
example of URM (Low-Rise)
4. RESPONSE CURVE AND CAPACITY CURVEThe building performance (peak response) for particular ground motion isdetermined by intersection of capacity curve of building and seismic
response spectrum, the standardized response spectrum shape as given in
IBC 2006 (SELENA V2.0, 2007), which consist of four parts, peak groundacceleration, region of constant spectral acceleration at period of zerosecond to TAV, a region of constant spectral velocity between period TAV
to TVD and region of constant spectral displacement for period of TVD andbeyond. The region of constant acceleration is defined by Sa at 0.3 s(Sa@0.3). The region of constant spectral velocity is defined by Sa is
proportional to 1/T and Sa at 1 s (Sa@1).
In general, the elastic design spectrum is defined by following
equations:
if 0 < T < TA
Sa (T) = Sa@0.3 (0.4+0.6 T/TA)(2)
Sa (T) = Sa@0.3
if TA < T< TAV(3)
Sa (T) = Sa@1.0/T
if TAV < T < TVD(4)
Sa (T) = Sa@1.0/T*T
if TVD < T < 10 s
(5)
The value of TAV is based on intersection of spectral acceleration andvelocity:
TAV = Sa@1.0 / Sa@0.3(6)
TA=0.2 TAV =0.2 (Sa@1.0 / Sa@0.3)(7)
The period TVD is based on the reciprocal of corner frequency (fc)
this frequency is estimated by using Joyner and Boore relationship(SELENA v2.0, 2007) as a function of Moment magnitude:
TVD = 1/fc =(8)
In order to be able to describe the elastic design spectra (for rock: siteclass B) in that case only PGA is give the following expression have to be
used:

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Sa@0.3 = SAS= 2.5 PGA(9)
Sa@1.0 = SAL = PGA(10)
In account of amplification of ground shaking multiply amplification
factor to PGA:
PGAi = PGA FAi(11)
The construction of demand spectra including soil effect can becalculated by using following expression:
SASi = SAS · FAi for short period amplification factor (FAi) for siteclass i.
SAli = SAl · FVi for long period amplification factor (FVi) for siteclass i.
While the period TAV, which defines the transition period fromconstant spectral acceleration to constant spectral velocity is a function of
the site class. It can be determined by the following equation:
TAVi = { SAl / SAS } { FVi / FAi }
(12)
4.1

Capacity curve

The building capacity curve is also known as push-over curve basedon engineering designed parameter and nonlinear elastic analysis method
which gives accurate estimation of building displacement. The capacity
curve of building construct under three control points the design capacity,
the yield capacity and ultimate capacity. The design capacity represent
nominal building strength, the yield capacity represent lateral strength andthe ultimate capacity represent maximum strength of the building. The
capacity curve represents characteristics of the structure, which is a plot oflateral resistance of building to the lateral displacement. For this study
development of building capacity curve for a model of concrete structure iscreated by using SAP 2000 analysis program.

Figure 3: (a): Standard shape of response spectrum (b)example of capacity curve for concrete structure.

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5. DEFINATION OF DAMAGE STATESThe peak building response is taken from the interaction of capacity curveand demand curve at the building location. The peak building response
either spectral displacement or spectral acceleration at the point ofinteraction is used as parameter with fragility curve to estimate the damage
state probabilities. The method adopted by HAZUS and in this study,
damage states are divided in four classes as shown in Table 2.
Table 2: damage states thresholds defines with the agreement of capacity
spectrum

Where,
Sd is spectral displacement and suffix 1, 2, 3, 4 show slightdamage, moderate damage, extensive damage, and complete
collapse respectively.
Ay = yield spectral acceleration
Au = ultimate spectral acceleration.
Dy = yield spectral displacement
Du = ultimate spectral displacement.
6. CUMULATIVE DAMAGE PROBABILITIESFor a given damage state, P [S | Sd ], P [M| Sd], P [E | Sd], P [C | Sd] afragility curve is well described by the following lognormal probability
density function Barbat et al, (2002), HAZUS (2003 ).
(13)
Where
is the threshold spectral displacement,is thestandard deviation of the natural logarithm of this spectral displacement
Table2 shows how the thresholdobtain from capacity spectrum, Φ isthe standard normal cumulative distribution function and Sd is the spectral
displacement of the structure.
Where,P [S | Sd] = probability of being in or exceeding a slight damage state,
S.
P [M | Sd] = probability of being in or exceeding a moderate damage
state, M.

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P [E | Sd] = probability of being in or exceeding an extensive damage
state, E.
P [C | Sd] = probability of being in or exceeding a complete damage
state, C.
Fragility curve Figure 4 which shows the probability of exceeding or
being in for expected spectral displacement (obtain from performance point)
for all damage states.

Figure 4: shows example of fragility curves
Discrete damage probabilities can be calculated as follows:
Probability of complete damage, P [C] = P [C | Sd]
Probability of extensive damage, P [E] = P [E | Sd] - P [C | Sd]
Probability of moderate damage, P [M] = P [M | Sd] - P [E | Sd]
Probability of slight damage, P [S] = P [S | Sd] - P [M | Sd]
Probability of no damage, P [None] = 1 - P [S | Sd](14)
7. EXAMPLE PROBLEM OF RM (LOW-RISE) STRUCTURE
7.1 Generation of elastic demand spectra (SELENA v2.0,
2007):
Demand spectra for NEHRP site classes B (rock site), PGA for rocksite conditions PGAB = 0.2 g
Step1) calculation of spectral acceleration at T= 0.3s and T= 1.0s,
According to equations (9) & (10):
Sa@0.3 = SAS = 0.5g
Sa@1.0 = SAl = 0.2g
Step2) site amplification factor for site given by IBC-2006(SELENA V2.0, 2007)
Table 3: site amplification factor
Site amplification factor =Site class B
SAS = 0.5g, SAl = 0.2g
FA
1.0
FV
1.0

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Step3) calculation of short period and long period spectral
accelerations as well as Transition period
Table 4: show calculated value of short and long period acceleration
Parameter
Class B
PGAi = PGA FAi
0.2
SASi = SAS · FAi
0.5
SAli = SAl · FVi
0.2
TAVi = { SAl / SAS } { FVi / FAi }0.4
TA=0.2 TAV
0.08
Step4) Generation of elastic demand spectrum (damping ξ= 5%)
For the evaluation of structural damage it is more convenient to plot
the acceleration response spectrum as a function of the spectral
displacement. This could be achieved due to the relation between the
different spectral parameters:
Sd = Sa *g*T*T / 4 *(15)

Figure 5 (a) shows demand spectrum and Figure (b) shows demand
spectrum as a function of spectral displacement, values along abscissa ofspectral displacement is calculated by using equation (14), these curve areplotted by using MS-Excel software.

Figure 5: (a) demand spectrum (b) demand spectrum as a function of thespectral displacement
7.2

Generation of capacity curve using SAP2000:

For a low-rise reinforced concrete (RM) structure pushover analysis iscarried out. Following are the details of the structure.
• Grade of Concrete is 25 Mpa• Grade of steel is 415 Mpa• Slab thickness 100mm• Column 450 X 300mm, Beam 350X250mm• Live load 4kN/m2, storey height 3m
Figure 6(a) shows result of pushover analysis using SAP2000 for astructure in the form of capacity curve. The values of yield acceleration,

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ultimate acceleration, yield spectral displacement and ultimate spectral
displacement are given in the Table 5 which can be read directly from
capacity curve. Figure7 is a plot describes intersection of capacity curve anddemand spectrum, the corresponding value of spectral displacement at theintersection point is a performance point (peak response) of the structure
and peak response for taken RM (Low-Rise) structure is given in Table 6.

Figure 6: a) capacity curve b) Example of RM (L) structure generated in
SAP2000
Table 5: yield and ultimate values from capacity curve for RM (L)Yield capacity
Dy cm
Ay (g)
2.9
0.42

Ultimate capacity
Du cm
Au (g)
8.18
0.53

Figure 7: Intersection of capacity curve and demand curve
Table 6: peak building response from intersection of demand and capacity
curve
Peak building response in cm
Model building
RM (L)
Sd (cm)7.3

Reinforced concrete
structure
3 cm

Calculation for cumulative damage probability:
According to equation 13 For a given damage state, P [S | Sd ], P [M|

Sd], P [E | Sd], P [C | Sd]

is the threshold spectral displacement,

Estimation of Risk Due to Earthquake Hazard in AP, India an it Based Approach169

December 2007, Dhaka, Bangladesh

Table 2 shows how the thresholdobtain from capacity spectrum(Barbat et al 2002) andis the lognormal standard deviation parameterthat describes the total variability of damage state (HAZUS 2003), Table 7
show the values ofandtaken from HAZUS in this study.

for each damage state, values ofTable7: Parameter for fragility curve defined by HAZUS for RM (L) typemodel building
SlightModerate
Extensive
Complete
Type
βS
βM
βE
βC
RM(low4.872 1.05 6.96
1.07 10.128
1.09 19.63
0.91
rise)
Table 8 shows calculation of probability of being in or exceedingdamage states by using equation 13, and the discreet damage probabilities iscalculated by using equations (14) and it is represented in Table 9
Table 8: calculation of cumulative probabilities of RM (L)X
Damagestate
SlightModerate
Extensive
Complete

7.5
7.5
7.5
7.5

Sd/

βds

Sd

4.872
6.96
10.128
19.63

y

1.05
1.07
1.09
0.91

1.53
1.07
0.74
0.38

ln(x)/
βds
0.42 0.40
0.06 0.05-0.30 -0.27-0.96 -1.06
ln(x)

Φ[y]
0.65540.51990.38590.1446

Table 9: damage probability matrix for RM (L)Damage probability Matrix for RM(L)
Model
type
RM(L)

SlightModerate

Extensive

Complete

P[S]

P[M]

P[E]

P[C]

0.13550.13400.24130.1446

Figure 8: damage probability graph of RM (L) building type
The Figure 8 represents the discrete damage probabilities of class RM(Low-rise) for all damage states calculated by method explained above andshows Structure is more vulnerable to Extensive damage and less vulnerable

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to Moderate damage for a generated response spectrum of PGA= 0.2g forsite class B (rock site).
8. CONCLUSIONSThe efforts applied to compute the Damage Probability Matrix for a given
building type is with the objective to develop a tool or a computer based
program which provides assessment of risk due to earthquake for an area
like Andhra Pradesh or any other part of the country.
The next objective is generation of capacity parameters for allbuilding types, development of more distinct classification based on seismic
design level and probability matrices for collective numbers of buildings.
The last step of the project will be development of user interface byusing programming language like C# or Visual Basic, and the expected time
to complete the project is within the next 3 months.
REFERENCES
Wen-I L, Chin-hsiung L 2006. Study on the fragility of building
structures in Taiwan, Natural Hazards (2006) 37:55-69,
National university of Kaohsiung.
Ggulati. B 2006. Earthquake assessment of buildings: applicabilityof HAZUS in Dehradun, India. Unpublished report, Indian
institute of remote sensing, Dehradun, India.
Barbat A. H, Lagomarsino S, Pujades L.G. 2002. Vulnerability
assessment of dwelling buildings. projects: REN 2001-2418C04-01 and REN2002-03365/RIES Universitat Politdecnica
de Catalunya, Barcelona, Spain, University of Genoa,Genoa,
Italy.
HAZUS-MH 2003. Advance engineering building module. Report
by: Department of Homeland Security Emergency
Preparedness and Response Directorate FEMA Mitigation
Division Washington, D.C.
SELENA v2.0 2007. seimic loss Estimation using a logic tree
approach. prepared by Sergio Molina-Palacios, Dominik H.
Lang, and Conrad D. Lindholm at NORSAR Kjeller, Norway.
Vulnerability Atlas of India (2007), Building Materials &Technology Promotion council Govt. of India.
International Code Council (2006). International Building Code
(IBC-2006). United States, January 2006, 664 pp.
Joyner, W.B. and Boore, D.M. (1988). Measurement Characterization andPrediction of Strong Ground Motion. Proc. of Earthquake Engineeringand Soil Dynamics II, 43–102. Park City, Utah, 27 June 1988. New
York: Geotechnical Division of the American Society of Civil
Engineers

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New Technologies for Urban Safety of Mega Cities in Asia

MODEL TESTSMEASURING EARTH PRESSURE
ACTING ON BURIED STRUCTURE
DUE TO DIFFERENTIAL SETTLEMENTREIKO KUWANO
International Centre for Urban Safety Engineering,
Institute of Industrial Science, The university of Tokyo, Japankuwano@iis.u-tokyo.ac.jp
TOSHIYUKI HORII
Wakachiku Construction Co. Ltd., Japantoshiyuki.horii@wakachiku.co.jp
HIDETOSHI KOHASHI
Material and Geotechnical Engineering Research Group,
Public Works Research Institute, Japankohashi@pwri.go.jp
ABSTRACTA series of trap door tests was conducted to evaluate the change inearth pressures acting on a buried structure in a high embankment due todifferential settlements. A model structure, box or pipe, was placed on thecentre of a soil chamber having movable base platens at both sides.
Differential settlements were given by moving the base platens down
simultaneously.
It was found that the size, shape and burial depth of a buried structure
and mechanical properties of backfill soil are governing factors for theincrement of vertical earth pressure at the top of the structure, while theconstruction/settlement history showed only minor effects. Even a simple
calculation, where the friction forces generated between the soil mass above
the structure and surrounding soil are taken into account, can offer
reasonable estimation for the increment of earth pressure.

1. INTRODUCTION
Earth pressures acting on underground structures are highly dependent on
the interaction between ground and structure. Increase in the vertical earthpressures acting on a buried structure in high embankment should be,therefore, considered, depending on the size and depth of structure and typeof foundation, since differential settlements are often expected in suchconditions. However, in practice, the increment of vertical earth pressureson underground structures is estimated in the empirical manner, mainly
based on the information of past earth pressure measurements in the limited
number of sites (see for example General guidelines for road earthworks,

173

December 2007, Dhaka, Bangladesh1999). In such estimation, the degree of settlement and/or mechanicalproperties of backfill materials are not always taken into account.
In this study, a series of trap door tests was conducted to see how
differential settlements affect on earth pressures acting on a buried structure
in sandy soil.

2. APPARATUS AND TEST PROCEDURE
Figure 1 schematically shows a model ground including a soil chamber, aburied model structure and the locations of earth pressure transducers. The
soil chamber is 100cm wide, 60cm long and 60cm deep. The base of thechamber is separated into 3 platens. The centre base platen is fixed, on
which a rigid box/pipe structure was placed, while both side platens canmove down simultaneously. Earth pressure transducers were directly
attached on top and sides of the model structure, and the center of movingbase platens.

１B～４B

box／pipe
B

down

down
top
side

600

1

5

base
2

4

6

150

7
150

3
250

445

250

110

445

Figure 1: A soil chamber having separated moving baseplatens and location of earth pressure transducers.
Toyoura sand and sand with fines were used for the material of model
ground. Each sand was compacted at the relative density of approximately
80% in layers of 2.5cm, up to the specified height. Soil cover was varied
from 11cm to 44cm, i.e. 1B to 4B, where B is the width (and in this casealso the height) of the buried structure. A downward movement of movingbase platens was given at a displacement rate of 0.1mm/min up to174

New Technologies for Urban Safety of Mega Cities in Asia

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approximately 1mm. The measurements were continued up to at least 20
minutes after the movement of base platen was completed. Test cases andconditions are shown in Table 1.

Model
GroundSandρd:1.57g/cm3

Sand+Fines 20%
ρd:1.53g/cm3

Soil
cover
(cm)
44

Table 1: Test conditions.
Test Case

1 stage test;
Downward moving ofbase platen by 1mm
with soil cover of 44cm
11, 22, 4 stage test;
33, 44
Downward moving ofbase platen by 1mm foreach stage. Soil coverfor the 1st stage was
11cm, then backfillingto 22cm, 33cm and44cm (displacement of
4mm in total)
44
1 stage test
11, 22, 4 stage test
33, 44

Type of
Model
Structure
Box

Case
No.
X1

Pipe

P1

Box

X2

Pipe

P2

Box
Pipe
Box
Pipe

X3
P3
X4
P4

3. TEST RESULTS
3.1 Change in earth pressures with settlements of surrounding
groundRelationships between displacements of moving base platen and earthpressures at three locations in test Case X1and P1 are shown in Figure 2.
Measured values from pressure transducers No.1 and 7, No.2 and 6, andNo.3 to 5 are averaged and shown as pressures at “base”, “side”, and “top”,
respectively. Overburden pressures calculated from depths of pressuretransducers (55cm for base, 44cm for top) are also shown in broken lines.
In case X1, with settlements of surrounding ground, the earth pressure
acting on the top increased, while the base pressure decreased. The value of“top” pressure doubled at a displacement of 0.3mm, then gradually
increased up to 2.4 times of the initial value at a displacement of 0.9mm.
The horizontal earth pressure acting on the side of the box, initially about ahalf of overburden pressure, showed marginally increase as the surrounding
ground settled. Similar trend was observed in Case P1, except that pressurechange at top was larger than those in case X1, possibly due to an effect ofstress concentration caused by its convex shape.

(Box)
Model Tests Measuring Earth Pressure Acting on Buried Structure Due to Differential Settlement

175December 2007, Dhaka, Bangladesh

30

Case X1

Earth pressure （kPa)

25
20

top

sand
４B

15
10

depth
55cm
44cm

base

top
base

5

B

side

down

side

0
0

0.2

0.4

down

Horizontal earth pressure（K=0.5)

0.6

0.8

1

Displacement （ｍｍ）

Earth pressure （kPa)

30

Case P1

25

top
20

４B
15
depth
55cm
44cm

base

10

top
base

5

side

B

down

0
0

down

Horizontal earth pressure（K=0.5)

side
0.2

0.4

0.6

0.8

1

Displacement （ｍｍ）

Figure 2: Change in earth pressures during a downward movementof base platens (Case X1&P1)

3.2

Effects of construction/settlement history
30

depth
１１cm

２２cm

３３cm

４４cm

Earth pressure （kPa)

25

１B

20

２B
top

base side

15

top

B

down

top
base

1

B

down

down

2
Displacement （ｍｍ）

４B

Horizontal earthpressure（K=0.5)

side

0
0

down

depth
55cm
44cm

10
5

base side

3

4

top
base side

B

down

down

Figure 3: Changes in earth pressures during 4 stages of moving baseplatens descent (Case X2)
Changes in earth pressures in Case X2 are shown in Figure 3. In thiscase, the model ground was constructed at four stages. At the beginning, asoil cover was constructed to be 11cm, 1B (where B is the width/height ofthe box). A displacement of 1mm was given, then the next construction,
backfilling up to a soil cover of 2B, was made. Test was conducted at soil
depths of 1B, 2B, 3B and 4B in the same manner. Overall displacements
were, therefore, 4mm. In this 4-stage test, as shown in Figure 3, the same

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trend, increase in “top” and “side” pressures and decrease in “base”
pressures are seen at all the stages.
Figure 4 shows change in ratios of “top” pressures during and the
beginning of stage (before a descent of moving platens). Except for the step
1, the final increase ratios are about 1.3 to 1.5. Most of the earth pressure
increase was generated within a displacement of 0.2 to 0.3mm.

Increase in “top” pressurecompared to the initial value
at each stage

2stage２

1.5

stage3stage41stage1
0.5

0
0

0.2

0.4
0.6
0.8
Displacement （ｍｍ）

1

Figure 4: Changes in “top” pressures compared to the initial values at
each stage (Case X2)
3.3

Effects of backfill soil

The test results of Case X3 are shown in Figure 5, in which the model
ground was made of sand with 20% fines content. The change of earthpressures was far moderate and gradual compared to that in Cases with
Toyoura sand. The final increase in “top” pressure was about 1.5 times ofthe overburden pressure.
30

Earth pressure （kPa)

25
20

４B

15

Sand with
fines

top

10

depth
55cm
44cm

base

5

Horizontal earthpressure（K=0.5)

side

0
0

0.2

0.4

0.6

0.8

top
base side

B

down

down

1

Displacement （ｍｍ）

Figure 5: Changes in earth pressures during a descent of movingbase platens (Case X3)
3.4

Increase in pressure acting on top of the box

Variations of ratios of “top” pressures to overburden pressures for box
and pipe structures are plotted against displacements of a base platen in
Figure 6.

Model Tests Measuring Earth Pressure Acting on Buried Structure Due to Differential Settlement

177

December 2007, Dhaka, Bangladesh

Ratio of earth pressure at top andoverburden pressure

5

Box

4

１～４B

X2: Sand １～４B

X1: Sand ４B

3

top

X3: Sand withfines ４B

2base side

X4: Sand with fines
１～４B

1

B

down

down

0
0

Ratio of Earth pressure at top andoverburden pressure

5

1

2
3
Displacement （ｍｍ）

4

5

pipe
P1: Sand ４B

43

P2: Sand １～４B

P3: Sand withfines ４B

１～４B

2

P4: Sand with fines １～４B

top
base

1

side

B

down

down

0
0

1

2

3

4

5

Displacement （ｍｍ）

Figure 6: Ratios of “top” pressures and over burden pressures
For all the cases, there was small decrease in ratios during at least 20
minutes resting time after a displacement of 1mm was given, due to thestress relaxation. For Cases X2, X4, P2 and P4, plotted curves are
discontinuous between stages. As the backfilling progressed, the ratios
automatically decreased due to the increase of depth.
The figure indicates that the governing factors for the increase of earthpressure acting on a buried structure are;a) Depth of a buried structureb) Mechanical properties of backfill soil, andc) Relative displacement between soil and structure. On the other hand,construction and/or displacement history appeared to have an only
minor effect, as the final values of ratios are similar between 1 stage
test and corresponding 4 stage test. Increase in earth pressure at top
for pipe structure was distinctively large compared to that for box
possibly because of stress concentration.

4. ESTIMATION OF EARTH PERSSURE INCREMENT
Change in the distribution of earth pressures due to a displacement ofmoving platens is calculated, based on the simple assumption that the soil

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mass above the buried structure is pulled down due to the downward
frictions acting on the boundary by the surrounding soil, as shown in
Figure 7.
Vertical earth pressure
Initial earth pressure

frictionｈ

B
B

Figure 7: Earth pressure distribution during a movement of base platens
for a buried box structure
When a depth of the structure is h, the friction force for both sides perunit length, F, is;hF = 2 × ∫ Kγz tan φ ⋅ dz = Kγh 2 tan φ(1)where K is earth pressure coefficient, γ is unit weight of soil, and φ is angleof shear resistance. A ratio of “top” pressure and overburden pressure, α, is;Bγh + F
Kh tan φ
α=
= 1+
Bγh
B
(2)
where B is a width of a box.
0Here, although the vertical pressure at a depth of z is simply estimatedto be γz, the vertical earth pressure during a descent of moving platens
varies especially around the box. Kikumoto et al. (2005) estimated the
distribution of vertical earth pressures for trap door testing based on
Terzaghi’s theory. The distribution of earth pressures for this test series
should be analogous and schematically shown in Figure 8. Yoshimmaru etal. (2006) performed numerical simulation for the earth pressures acting on
a buried box, showing that the vertical earth pressure just above and vicinityof a box increase as a result of the settlement of soil surrounding a box. In
this study, the value of K was tentatively chosen to be 0.6, considering thefact that the “side” pressure increased a little during a descent. In reality, thedistribution of earth pressure on a box is not necessarily uniform, yet thevalue of α calculated from the equation (2) is the average pressure. The
factor of structure’s shape, β, is therefore introduced, as shown in equation(3), in the calculation of “top” pressure, considering the non-uniform
distribution of earth pressure. The value of β would be larger for a buried
pipe, and smaller for a box with the larger width.
Kh tan φα = β (1 +)B
(3)Estimated values of α are presented in Figure 8. Parameters for the
calculation are given in Table 2.

Model Tests Measuring Earth Pressure Acting on Buried Structure Due to Differential Settlement

179

December 2007, Dhaka, Bangladesh

Table 2: Parameters for the estimation of earth pressure increase
Sand

Angle of shear resistance, φEarth pressure coefficient, K
Effect of shape, β35°Sand with
fines
20°
0.6

Box
(B×B)

Pipe

1.0

1.3

Ratio of pressure increase, α

The value of φ for sand with fines is an only tentative estimation.
5(calculated)Toyourawith fines
Toyoura 4B(measured)
Toyoura 1-4B
with fines 4B
with fines 1-4B

4

3

Box

2

1

0
0

1

2

3

4

5

Ratio of pressure increase, αDepth, ｈ/Β
5

Pipe
4

3

2

Toyoura (calculated)with fines
Toyoura 4h
Toyoura 1-4h (measured)with fines 4hwith fines 1-4h

1

0
0

1

2

3

4

5

Depth, ｈ/Β

Figure 8: Ratio of “top” pressures and over burden pressures,comparison between the estimation and experiment.
The evaluation of earth pressures acting on buried structures are, when
the differential settlement occurs, generally not so easy, as the structure andsurrounding soil are subjected to complicated phenomena, like groundarching, soil-structure interaction, and so on. But even a simple calculation
adopted in this study can give approximately reasonable values. Besides thecontinuous effort for accumulating field data, a theoretical approach shouldbe also considered to improve the estimation.

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5. SUMMARY

In order to evaluate the increase in vertical earth pressures acting on aburied structure due to the differential settlements, such as a box culvert or aburied pipe in high embankment, a series of trap door tests was conducted.
The following tentative conclusions has been obtained so far;
• An increase in vertical earth pressures on a structure is affectedby a depth of a buried structure, mechanical properties of soil,
and possibly the shape of structure. Mechanical properties ofbackfill materials are not taken into account in the current
empirical estimation in practice.
• Construction and/or settlement history has little effect.
• Increments of vertical pressures obtained in series of experimentcan be roughly simulated by the simple calculation, where thefriction forces generated between the soil mass above thestructure and surrounding soil are taken into account.

REFERENCES

General guidelines for road earthworks - culvert work -, 1999. Japan roadassociation, ISBN 978-4889504101, Maruzen Print Co. Ltd. (inJapanese).
Kikumoto, M., Kishida, K., Kimura, M. and Tamura, T., 2005. Formula for
calculating the distributions of vertical earth pressures around a tunnel,
the 40th domestic conference of geotechnical engineering,
Proceedings of the 40th annual conference, Japanese GeotechnicalSociety, Hakodate, July 2005, Paper No. 918. (in Japanese).
Yoshimaru, T., Sakajo, S., and Nishioka, T., 2006. Numerical analysis ofearth pressure acting to the embedded box tunnel, the 41st domestic
conference of geotechnical engineering, Proceedings of the 41st
annual conference, Japanese Geotechnical Society, Kagoshima, July
2006, Paper No. 876. (in Japanese)

Model Tests Measuring Earth Pressure Acting on Buried Structure Due to Differential Settlement181

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LANDSLIDE HAZARD ANALYSISFOR URBAN AREA USINGRASTER DATA SET
MD. ZAHID HASAN SIDDIQUEE
Research Assistant
Dept. of Civil Engineering, BUET
zh027@yahoo.com
MOSUR AHMED
Stereo Manager, Decode Limited
Dhaka, Bangladesh
RUBEL DAS
Research Assistant
Dept. of Civil Engineering, BUETABSTRACT
Landslide is one of the deadliest natural calamities that can play
havoc on the lives and resources. The intensity is always higher in urban
areas than that of counter parts because of higher population densities andman made structures. Countries like Philippines (17th February,2006) and
Bangladesh(11th June, 2007) have experienced some of the serious
landslides recently. Many other cities in Asia have also potential threat forlandslides. This is an important issue for securing urban safety especially inthe mega cities of Asia. A landslide is a geological phenomenon which
includes a wide range of ground movement, such as rock falls, deep failureof slopes and shallow debris flows. Although gravity's action on an oversteepened slope is the primary reason for a landslide, there are othercontributing factors affecting the original slope stability. In this paper an
attempt is made to focus on three main factors generating landslides such asmorphology of the soil, land use pattern and the steepness of the area. Hereweighted maps are prepared for each of the category following statisticalmethod based on pixel values of the Raster data (images). For instancepixels having higher values in the image for geological category pose
greater threats from landslide disaster while the areas having lower pixel
values indicate the less risk for landslides. Using the aforesaid methods
weighted maps for each of the type (geology, soil and slope) has been made.
Hereinafter all three weighted maps are overlaid to have a combined index
map for landslides in the study area. The index map represents the potential
threat areas for landslides with color intensities. The result of this study canbe very helpful for new developments in the landslide prone cities in Asia.
This can also play an important role for the built up areas in the city
regarding mitigation and preventive measures from landslides.

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December 2007, Dhaka, Bangladesh

1. INTRODUCTION
Landslides are the phenomena which represent the general heading of mass
movement. The term therefore describes a movement of a mass of rocks orsoil from a higher point to a lower one. Movements may include falling,sliding and flowing. The first is the movement of masses or blocks in free
fall; the second is the movement along more or less well-defined surfaces,
the third, is movements of masses in a fluid-plastic or viscous state.
Movements should be downwards and outwards with a free face, thus
excluding subsidence. Subsidence is a mass movement, in which a mass
goes downwards induced by gravity and/or specific water conditions. The
displaced material may include parts of the regolithe and/or bedrock. The
materials involved can therefore be rocks at various levels of alteration or
the product of desegregation phenomena in the past. Gravity is the principal
force involved. The movement of the masses is due to the action of the forceof gravity, but other forces like those due to earthquake or due to water
filtration can be involved. On the basis of what is stated above, a complete
definition of a landslide event could be the following: Movement of soil orrock controlled by gravity, superficial or deep, with movement from slow torapid, but not very slow, which involves materials which make up a massthat is a portion of the slope or the slope itself.

2. TYPES OF LANDSLIDES
There are different types of landslides and they can be categorized in a
number of ways. The most common ones are described bellow in short.
2.1

Debris flow

In this type of landslides slope materials which are saturated withwater resulted into debris flow or mud flow. Consequently the slurry of rockand mud may uproot trees, houses, and cars. This can also block the bridges
and tributaries causing flooding along its path.

Figure 1: A landslide caused by one of the 2001 El Salvador earthquakes

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Muddy-debris flows in the affected areas cause severe damage tostructures and infrastructure and often claim human lives. Muddy-debris
flows can start as a result of slope-related factors, and shallow landslides
can dam stream beds, provoking temporary water blockage.
2.2

Earth flow

This is the flow of viscous and saturated fine-grained materials thatmove at any speed along the downward slope. Typically, they can move at
speeds from .17 to 20 km/h. Though these are a lot like mudflows, ingeneral they are slow moving and are covered with solid material carriedalong by flow. Clay, fine sand and silt, and fine-grained, pyroclastic
material are all susceptible to earthflows. The velocity of the earthflow is all
dependent on how much water content is in the flow itself: if there is morewater content in the flow, the higher the velocity will be.

Figure 2: A rock slide in Guerrero, Mexico.
This type of landslides is much likely to happen during periods of highprecipitation, which saturates the ground and adds water to the slope content.
Fissures develop during the movement of clay-like material creates theintrusion of water into the earthflows. Water then increases the pore-waterpressure and reduces the shearing strength of the material.
2.3 Sturzstrom
Sturzstorm happens rarely and the much of this type are not yet
understood. Often very large, these slides are unusually mobile, flowing
very far over a low angle, flat, or even slightly uphill terrain. They aresuspected of "riding" on a blanket of pressurized air, thus reducing friction
with the underlying surface.

Landslide Hazard Analysis for Urban Area Using Raster Data Set

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December 2007, Dhaka, Bangladesh

2.4

Shallow landslide

The sliding surface is located within the soil mantle or weathered
bedrock in this form of landslide. They are normally to a depth from few
decimetres to some meters. Shallow landslides include debris slides, debris
flow, and failures of road cut-slopes. Landslides occurring as single large
blocks of rock moving slowly down slope are sometimes called block glides.
2.5

Deep-seated landslide

Here in this type the sliding surface is in most of the cases deeply
located below the maximum rooting depth of trees which may vary to adepths greater than ten metres. Deep-seated landslides usually involve deep
regolith, weathered rock, and/or bedrock and include large slope failure
associated with translational, rotational, or complex movement.

3. CAUSES OF LANDSLIDESIn broad category there are two types of causes for landslide such as naturalcauses and man made causes. A concise discussion is provided in thefollowing sections over the causes of landslides.
3.1

Natural Causes

Earthquake has a very strong relation with landslides. During theearthquake it creates the huge stress that make the weak slope to failresulting in a landslide. River erosion and heavy rains are the two otherimportant reasons that can trigger the landslide. Volcanic eruptions can
produce loose ashes and debris to flow those can also be an important
contributing factor to make a landslide.
3.2

Man Made Causes

Deforestation, mining and overgrazing are the main causes made byhuman activities which lead to landslides. Stockpiling or from man-madestructures may stress weak slopes to fail those can lead to a landslide.

4. METHODOLOGY
Based up on the following formula Weight Map for each of the category has
been made. Then the three weighted maps for the type geology, slope andland use are put together to generate the combined map. This index map is acolor coded one that shows the potential threat area for the landslide hazards.
The landslide density per class is divided by the landslide density in theentire map. Negative weights when the landslide density is lower thannormal. Positive when it is higher than normal

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Wi = the weight given to a certain parameter class (e.g. a slope class)
Densclas = the landslide density within the parameter class
Densmap = the landslide density within the entire map
Npix(Si) = number of pixels whcich contain landslides in a certain
parameter class.
Npix(Ni) = total number of pixels in certain parameter class

Figure 3: Diagram for work flow

5. AVAILABLE DATA
Data is most important item in spatial analysis. Once the database is ready it
is only a matter of time to have the desired output. We had the vector andraster data set for land use, geology and slope of the study area. The rasterdata is composed of small square parts called pixel. This type of data can be
monochromatic or panchromatic. The study area is located in near Bogota,
the capital city of Columbia.
Input dataset: Geology map (vector, ArcView Shape file) Landslide map (vector, ArcView Shape file) Landuse (raster)+tfw file Slope map (raster)+tfw fileLandslide Hazard Analysis for Urban Area Using Raster Data Set

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December 2007, Dhaka, Bangladesh

We have used GIS software called GeoMedia form a company
Intergarph International. For analyzing the raster dataset we have used an
extension of GeoMedia called “Grid”.

6. ANALYSIS
Analysis covers the working procedures in GeoMedia Professional for
generating raster maps and then making weighted maps for the landslide
risk analysis. A brief from each of the sections is documented in thefollowing paragraphs.
6.1

Rasterizing the vector maps

There were two data sets with a nature of vector format. As we needthem to be in raster format, we have converted them from vector to rasterones. Here we have specified the pixel size in order to avoid the conflict inthe output data. Having completed rastarization the data sets are recoded
followed a randomization process.

Figure 4: Number of total pixels in different classes
6.2

Preparation Weight Maps

The landslide density per class is divided by the landslide density inthe entire map. Using the principle above weight maps for land use, slope
and geology are prepared. In this coding 0 indicates no threats regarding
landslide while positive numbers represents potential threats for landslide in
the study area.

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Figure 5: Weight Map for Slope Category
6.3

Combining all for Risk Maps

For making the landslide hazard maps, the weighted maps from all
categories like slope, land use and geology are put together. The output map
is colour coded map which indicates the potential threats of landslides withpositive numbers; zero represents neutral position regarding the risk ofhapping landslides and the negative numbers the less the risk of occurring
landslides.

Figure 6: Final Landslide Hazard Map

Landslide Hazard Analysis for Urban Area Using Raster Data Set

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7. CONCLUSION
Landslide is a devastating natural calamity and this is even more hazardous
in densely populated urban areas. Theses can play havoc on both resources
and lives. The outcome of this paper can be very helpful for the
professionals
from different
fields like planners, engineers
environmentalists. This can also help the decision makers to find out thesuitable areas for new urban developments. In recent years there were somesevere landslides in Asian cities like in Southern Leyte landslide in thePhilippines on 17 February 2006 and Chittagong (Bangladesh) on 11th June
2007. The mega cities in Asia are not out of this risk. So preparation ofLandslide Hazard Maps for theses cities can make a significant contribution
to mitigate loses of resources and lives.

REFERENCES
Integraph. (2005): GeoMedia command Wizard. Online Guide of GeoMedia
Professional. Integraph Corporation, USA.
Naranjo, J.L., van Westen, C.J. and Soeters, R. (1994). Evaluating the use of
training areas in bivariate statistical landslide hazard analysis- a casestudy of Colombia, ITC Journal 1994-3, pp 292-300.
Van Westen, C. J. (1994). GIS in landslide hazard zonation: a review, with
examples from the Andes of Colombia. In: Price, M. and Heywood, I.
(eds.), Mountain Environments and Geographic Information Systems.
Taylor & Francis, Basingstoke, U. K. pp 135-165.
Web Links
http://en.wikipedia.org/wiki/Landslide#Landslide_types
http://www.answers.com/biomass
http://www.wissenschaftwirtschaft-bw.de/index.php4

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SEISMIC MICROZONATION OF
COX’S BAZAR IN BANGLADESH
A. B. AFIFA IMTIAZ
Dept. of Civil Engineering, BUET, Bangladesh
afifaimt@gmail.com
MEHEDI AHMED ANSARY
Dept. of Civil Engineering, BUET, Bangladesh
ansary@ce.buet.ac.bd
ASHUTOSH SUTRA DHAR
Dept. of Civil Engineering, BUET, Bangladesh
ashutoshdhar@ce.buet.ac.bd
MOHAMMED JOBAIR
Dept. of Civil Engineering, BUET, Bangladesh
jobair98@yahoo.com
ABSTRACT
Landslide is one of the deadliest natural calamities that can play
havoc on the lives and resources. The intensity is always higher in urban
areas than that of counter parts because of higher population densities andman made structures. Countries like Philippines (17th February,2006) and
Bangladesh(11th June, 2007) have experienced some of the serious
landslides recently. Many other cities in Asia have also potential threat forlandslides. This is an important issue for securing urban safety especially inthe mega cities of Asia. A landslide is a geological phenomenon which
includes a wide range of ground movement, such as rock falls, deep failureof slopes and shallow debris flows. Although gravity's action on an oversteepened slope is the primary reason for a landslide, there are othercontributing factors affecting the original slope stability. In this paper an
attempt is made to focus on three main factors generating landslides such asmorphology of the soil, land use pattern and the steepness of the area. Hereweighted maps are prepared for each of the category following statisticalmethod based on pixel values of the Raster data (images). For instancepixels having higher values in the image for geological category pose
greater threats from landslide disaster while the areas having lower pixel
values indicate the less risk for landslides. Using the aforesaid methods
weighted maps for each of the type (geology, soil and slope) has been made.
Hereinafter all three weighted maps are overlaid to have a combined index
map for landslides in the study area. The index map represents the potential
threat areas for landslides with color intensities. The result of this study canbe very helpful for new developments in the landslide prone cities in Asia.
This can also play an important role for the built up areas in the city
regarding mitigation and preventive measures from landsliEarthquake
hazard zonation for urban areas, mostly referred to as seismic
microzonation, is the first and most important step towards a seismic risk

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analysis and mitigation strategy in densely populated regions, since damage
due to an earthquake may vary even within a few meters due to variation in
local site conditions. The Microzonation presents peak ground acceleration,soil liquefaction and spectral amplification which are required for seismic
hazard mitigation. These factors are highly dependent on the local soil
conditions and on the expected earthquakes. Cox’s Bazar and the nearby
area fall in the High Risk Zone for earthquakes. There has been also a rapid
urbanization of Cox’s Bazar in the last few decades including constructionof significant number of buildings and other structures. It is essential todevelop seismic microzonations of the area based on site characterizations.
Historical Information reveals that earthquakes of magnitude between 6 and7 have occurred around the city in the past. In this study, borehole
investigation conducted at 30 locations across the district is used forliquefaction potential analysis. Seismic Microzonation map has beendeveloped for Liquefaction Potential based on the analysis. Influence of
local soil conditions on ground shaking and subsoil stability around the
district has also been discussed.

1. INTRODUCTION
Cox’s Bazar, located in the southeastern part of Bangladesh, is a
strategically and economically important city of the country. It is a costal
district and famous for its natural beauty and as a tourist place. The longest
sand beach of the world is located at Cox’s Bazaar. The district is exposed
to most devastating natural disasters of the country. The earthquake has
recently appeared as additional threat to this region. Therefore, it isessential to develop an earthquake preparedness program for the region inorder to reduce the potential losses expected from the disaster. Soilliquefaction is a phenomenon in which a soil below the ground water table
loses a substantial amount of strength due to pore pressure generation fromstrong earthquake ground shaking. Liquefaction can have a significant andsometimes devastating effect on buildings supported on the upper soil layers
constructed without consideration of its consequences of liquefaction. Cox’s
bazar, situated beside the Bay of Bengal, consists of 8 Upazilas namely
Cox’s Bazar Sadar, Kutubdia, Maheshkhali, Ramu, Teknaf, Ukhia, andPekua. According to the parameters of Land based zonation of Coastal
Region, all these Upazilas are under Exposed Coastal Area where one fourthof the district is island (Uddin and Yasmin, 2005). It is mostly a hilly region
consisting of alluvial flood plain and sandy sea shore area. The area bottomof the hill can liquefy if the intensity of shaking is high, which may cause
land slide in the hilly region. On the other hand floodplains and sea shore
areas consisting of fine sand and silt deposit with shallow water table inmost of the places may liquefy during a strong earthquake. Most of thebuildings in the region were constructed without any seismic design
consideration. Presently strengthening or retrofitting efforts are essential forthese buildings in order to protect lives and properties. This paper deals withthe development of a liquefaction potential map for Cox’s Bazar District toquantify the spatial variation of the liquefaction condition for expected
typical earthquakes.

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2. CAUSES OF SOIL LIQUEFACTION
The general trend on understanding about the basic causes of liquefaction ofsands is a quite qualitative measure. If a loose saturated sand deposit issubjected to ground vibrations, it tends to compact and decrease in volume.
The effective stress in the sand deposit is equal to the difference between the
overburden pressure and the pore water pressure. If drainage is unable tooccur, the tendency to decrease in volume results in an increase in porewater pressure. So, with increasing oscillation, the pore water pressure will
be equal to the overburden pressure causing the effective stress to become
zero. Since the shear strength of a cohesionless soil is directly proportional
to the effective stress, the sand loses its strength completely and develops aliquefied state.
In more quantitative terms, it is now generally believed that the basic
cause of liquefaction in saturated cohesion less soil during earthquake is thebuildup of excess hydrostatic pressure due to the application of cyclic shear
stress induced by the ground motions. These stresses are generally
considered to be due primarily to upward propagation of shear waves in asoil deposit; although other forms of wave motions are also expected tooccur.

3. ASSESSMENT OF SOIL LIQUEFACTION
3.1

Methodology

There are a number of different methods by which the potential forliquefaction of a soil can be evaluated. The types of methods can beclassified into four categories (Rashid, 2000):
Category-1: Evaluation of liquefaction potential roughly based on
topographical and geological information
Category-2: Evaluation of liquefaction potential from N-value and grain size
distribution data, and estimates of peak surface acceleration.
Category-3: Evaluation of liquefaction potential from laboratory cyclic
shear testing of undisturbed samples, in light of dynamic response analysis.
Category-4: Evaluation of liquefaction potential by conducting in-situ cyclic
or blasting tests, or laboratory shaking table tests.
Because of their simplicity, methods that fall in the first and second
category are generally useful for formulating microzonation maps ofliquefaction potential for wide areas. Methods in the last two categories
provide a more rigorous examination of liquefaction at a single site, but are
too tedious and costly for survey-type applications. In this study, the second
procedure was adopted to formulate microzonation map of liquefaction
potential.
The second procedure involves a more direct use of geotechnical data,such as SPT-N value and means particle diameter, and estimates of peaksurface acceleration (Seed and Idriss, 1971). A liquefaction resistance factor

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December 2007, Dhaka, Bangladesh

FL, is calculated which is used to evaluate the liquefaction potential index, IL.
The method is briefly explained below.
3.2

Liquefaction Potential Based on N-Values

A simple method suggested by Seed and Idriss (1971) was used here
to evaluate the Liquefaction Resistance Factor, FL which can also be termed
as Factor of Safety. It is the most common and traditional method that uses
correlations between the liquefaction characteristics of soils and theStandard penetration Tests or N-value along with other parameters such as
grain size distribution curves of soils, overburden pressure, and estimatedpeak surface acceleration. The assessment of the liquefaction resistancefactor at any depth by this method involves comparison of the predicted
cyclic stress ratio (t/б´0) that would be induced by a given design
earthquake with the cyclic stress ratio required to induce liquefaction. For
this method, FL is calculated for a given depth of soil layer by the following
formula.
FL = R/L(1)

Liquefaction is assumed to occur at that depth if FL is less than 1.0.
Here, R is the in-situ capacity of soil to resist liquefaction expressed by
Cyclic Resistance Ratio (CRR) for earthquake of magnitude 7.5 and L is theearthquake load induced by a seismic motion expressed by Cyclic StressRatio (CSR). Cyclic Resistance Ratio for earthquake of magnitude 7.5 isdetermined based on corrected SPT as shown in Figure 1 (Seed et al. 1983).

Figure 1: Curves for getting CRRM=7.5 from corrected SPT blow count(Seed et al. 1983)

Table 1: Seed and Idriss (1983) original MSF

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Earthquake
Magnitude
6
6.75
7.5
8.5

MSF
1.32
1.13
1.00
0.89

Magnitude Scaling Factor (MSF), obtained from Figure 2, is used todetermine the Factor of Safety against Liquefaction for earthquakes otherthan of magnitude 7.5 and calculated as
FS = FL = CRR7.5/CSR * MSF(2)The shear stresses developed at any point in a soil deposit during anearthquake appear to be due primarily to the vertical propagation of shear
waves in the deposit. If the soil column above a soil element at depth “h”
behaved as a rigid body, the maximum stresses on the soil element would be(tmax)r = (γh)/g . αSmax = б0/g . αSmax
Where,(tmax)rαSmax =γg(3)=
total overburden pressure
estimated peak surface acceleration (in percentage of g)=unit weight of the soil=
acceleration due to gravity

The average cyclic stress ratio (tav/б´0) induced by an earthquake isgiven by the expression (Seed and Idriss 1971);
CSR = L = tav/б´0 = 0.65 (αSmax /g) (б0 /б´0) rd
Where,
б´0 =
=
rd

(4)

effective overburden pressurea stress reduction factor with a value less than 1 given by(1-0.015z) in which z (meters) is the depth of ground surface

Since the standard penetration resistance, N, measured in the field
actually reflects the influence of the soil properties and the effective
confining pressure, it has been found desirable to eliminate the influence ofconfining pressure by using a normalized penetration resistance N1, where
N1 is the measured penetration resistance of the soil under an effective
overburden pressure of 1 ton per sq. ft. So, before using the graph in Figure
1, normalized to the field SPT-N value is needed as follows:
N1 = CN . N(5)

Where,
N1 = modified N values

Seismic Microzonation of Cox’s Bazar in Bangladesh

195

December 2007, Dhaka, BangladeshCN= a correction factor

The correction factor, CN was provided by Murthy (1991) andpresented here as Figure 2.

Figure 2: Curves for Correction Factor from Effective Overburden
Pressure (Seed et al. 1983)
The severity of foundation damage caused by soil liquefaction
depends to a great extent on the severity of liquefaction, which cannot be
evaluated solely by the FL. Generally speaking, liquefaction under thefollowing condition tends to be severe:
1. The liquefied layer is thick
2. The liquefied layer is shallow
3. The FL of the liquefied layer is far less than 1.00
In order to take care of the above effect, the Japanese Bridge Code(Japanese Road Association, 1991) recommended a modification toprocedure then suggested by Seed et al. In this method the factor of safetyvalues, FL (Seed and Idriss, 1971) against resistance to liquefaction havebeen computed up to top 20 meters depth for all the bore holes and thesevalues have been subsequently converted into liquefaction potential index(IL) given by the following equation (Iwasaki et al., 1982):
20

IL =

F(z). w(z) dz(6)0

Where,
F(z) = (1- FL) for FL<= 1.0;w(z)= (10-0.5 z) for z<= 20 m;

196

F(z) = 0 for FL>1.0
w(z)= 0 for z>20m

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IL

= 0,
= 0-5,= 5-15,= >15,No Liquefaction
Low Liquefaction
Medium Liquefaction
High Liquefaction

IL has been used in this paper to express the measure of liquefaction
potential for a particular location and for further zonation of the area basedon a particular range of this index.

4. ASSESSMENT OF SOIL LIQUEFACTION IN COX’S BAZAR
4.1

Site Soil Condition and Data Collection

The procedure employed in this paper to assess the liquefaction
resistance of a soil deposit and predict the liquefied thickness, is based onStandard Penetration Test (SPT) blow counts in soil bore logs. A total of 30
soil boring logs with SPT have been used for liquefaction potential study of
Cox’s Bazar District. Most of the soil data are collected from the depths up
to 30 meters. Almost all the boring data include SPT N-value measured at
1.5 m (5ft) interval. The soil borehole locations used in this study are shownin Figure 3. Figure 4 shows sample bore log along with SPT-N values.

Figure 3: Cox’s Bazar District Map Showing Soil Borehole Locations

Seismic Microzonation of Cox’s Bazar in Bangladesh

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December 2007, Dhaka, Bangladesh

Figure 4: Sample SPT blow counts in a bore log
4.2

Estimation of Liquefaction Potential

In this simplified procedure of liquefaction estimation, SPT values(Figure 4), unit weight of soil, location of water table and estimatedmagnitude of earthquake or estimated peak surface acceleration at site are
required. A series of historical earthquake data, from 1955 to 2006, havebeen analyzed to find out the relevant intensities based on Earthquake
intensity-attenuation relationship for Bangladesh (Sabri, 2001) and thus todetermine the PGA values.
The maximum ground surface acceleration for Cox’s Bazar has been
estimated, as 0.32 g, from the historical earthquake data. The magnitude has
been found to be around 6.24 and the relevant Magnitude Scaling Factor(MSF), as shown in Table 1, has been used to convert CRRM=7.5 for theselected earthquake by using equation (2). Particle diameter data for aparticular depth of soil was obtained from sieve analysis report (Figure 5)
which have been used in curve selection from Figure 1 to obtain CRRM=7.5.
At last the liquefaction resistance factor FL, for the top 20 m of soil and theresulting liquefaction potential, IL, for the 30 sites have been calculated.

Figure 5: Sample Grain Size Distribution Curves
5. GENERATION OF MICROZONATION MAP

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The computed results from the liquefaction potential analysis havebeen exported to a GIS environment for further processing and visualization.
They have been classified into different classes according to the extent ofliquefaction observed and plotted on the Cox’s Bazar district map dividing
the study area into 4 zones namely, high, medium and low probability ofliquefaction and no liquefaction zones. From the findings, finally a zonationmap (Figure 6) has been developed for liquefaction potential by using
spatial interpolation and converting the vectorial point features into
continuous raster map through grid generation which has been shown as
Figure 7. It has been observed that the Sandy Silts with trace clay, Layer ofSilt and Sand, Silty Sand having greater particle diameters and low to
medium SPT N-values are responsible mostly for higher liquefaction
potentials. The liquefaction potential index was very low for the borehole
locations around Teknaf which has resulted in No to Low liquefiable zones
in the map. Most of the locations near Chakaria and Kutubdia were found tohave extremely high IL values which have been reflected on the map. For
the rest of the borehole locations, there were different variations in thecomputed IL, from Moderate to High values. During grid generation to get
continuous raster map in GIS, the program counted on the more contributing
points on the surface. By combining the variations of effects of the points
the Moderate liquefiable zonation boundary was determined. The generated
microzonation map can be used as a guideline for General and Effective
Land Use planning, Zoning Ordinances, Capital Invest Planning, Groundfailure Susceptibility Estimation, Post Disaster Planning, Disaster
Mitigation Planning etc.

N

Figure 6: Seismic Microzonation Map of Cox’s Bazar for Liquefaction
Potential

Seismic Microzonation of Cox’s Bazar in Bangladesh

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December 2007, Dhaka, Bangladesh

5. CONCLUSIONS
Many countries of the world use zoning maps based on geologicalassessments of seismic hazards to consider dynamic effects in design codes
in order to ensure the safety of structures under earthquake loading. In thispaper, an attempt has been made to develop a firsthand liquefaction
potential map for the District of Cox’s Bazar using Seed’s simplified
procedure combined with modification from Japanese Road Association
1991. It can be concluded from this study that mainly Chakaria andKutubdia Upazilas are highly susceptible to soil liquefaction. The result of
this study would be helpful for policy makers and professionals toincorporate these guidelines in the seismic design process as well as
strengthening of the existing structures in these zones.
ACKNOWLEDGEMENT
The authors acknowledge the funding of this research project by United
Nation Office for Project Service (UNOPS) through Comprehensive
Disaster Management Program (CDMP) of the Ministry of Disaster Relief
and Rehabilitation of Bangladesh Government.

REFERENCES
Iwasaki, T., Tokida, K., Tatsuoka, F. Watanabe, S., Yasuda, S. and Sato, H.
1982. Microzonation for soil liquefaction Potential using Simplified
Methods. 3rd International Microzonation Conference, Proceedings,
1319-1329.
Iwasaki, T. 1985. Soil liquefaction Students in Japan: State of the Art. Soil
Dynamics and Earthquake Engineering, 5(1), 2-68.
Japanese Road Association 1991. Specifications for Highway Bridges, Part
V. Earthquake Resistant Design.
Murthy, V. N. S., 1991. Soil Mechanics and Foundation Engineering.
Volume 2, Revised and enlarged third edition, SAITECH, Bengalore,
India.
Rashid, MA (2000). Seismic Microzonation of Dhaka City based on site
amplification and liquefaction. M.Engg. Thesis, BUET, Dhaka.
Sabri, S. A., 2001. Earthquake intensity-attenuation relationship for
Bangladesh and its surrounding region. M.Engg. Thesis, BUET,
Dhaka,Bangladesh .
Seed, H.b. and Idriss, I.M. (1971). Simplified Procedure forEvaluating Soil
Liquefaction Potential. Journal of the SoilMechanics and foundations
Division, ASCE, 97(SM9), 1249-1273.
Seed, H.B. Idriss, I.M. and Arango, I., 1983. Evaluation of Liquefaction
Potential Using Field Performance Data. ASCE Journal of
Geotechnical Engineering, 109(3), 458-482, March 1983.
Uddin, A. M. K. and Yasmin, A. (2005). District Information-Cox’s Bazar.
Water Resource Ministry, Water Resource Planning Organization,
People’s Republic of Bangladesh Government

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INFLUENCE OF RE-CURING CONDITION
ON DAMAGE AND RECOVERY
OF MORTAR EXPOSED TO FIRE
MICHAEL HENRY
Department of Civil Engineering, University of Tokyo, Japanmwhenry@iis.u-tokyo.ac.jp
YOSHITAKA KATO
International Center for Urban Safety Engineering,
Institute of Industrial Science, University of Tokyo, Japankatoyosh@iis.u-tokyo.ac.jp

ABSTRACT
Concrete structures exposed to fire suffer from strength reduction andexplosive spalling, and must be repaired before returning to service.
Existing repair methods typically involve the removal of unsatisfactory
concrete and casting of a fresh patching material in order to meet strength,
durability, and fire protection requirements. However, this method
generates waste and consumes resources. A potential repair system utilizing
the re-curing of fire-damaged concrete to recover mechanical properties
would eliminate the generation of waste and reduce material consumption
while optimizing the life cycle performance of the existing structure.
This research attempted to gauge the potential for strength recovery
by re-curing fire-damaged mortar under different conditions and measuring
the change in strength relative to the pre-fired strength. Observation of thepore structure was performed, and these changes were related to thechanges in strength. It was found that strength recovery is possible when thedamaged mortar is supplied with water, although pre-fired strengths were
not achieved. Damage prevention was found to be more effective than recuring when considering the final strength of the re-cured specimen. The
formation of cracks contributed to large strength reductions in somespecimens; steel fibers were found to be effective in reducing the strength
loss due to their crack-bridging behavior. Pore structure recovery was also
observed. Discrepancies between strength and pore recovery could be
explained by cracking of specimens caused by differential thermal shrinkageor quenching.

1. INTRODUCTION
Concrete, when used in structural applications, is generally considered tohave good fire performance due to its low thermal conductivity and highspecific heat. One of the advantages of concrete over steel is that concrete
structures do not require fireproofing to achieve an acceptable fire rating,201

December 2007, Dhaka, Bangladesh

thus reducing construction costs. However, this does not mean that concrete
is impervious to fire. Fire damage to concrete includes explosive spalling
and reduced strength, durability, and fire protection.
If a structure has been exposed to fire, the severe visual appearance offire-damaged concrete may lead to the premature decision to demolish thestructure. However, it is important to evaluate the level of damage caused
and determine whether repairs can be made to the structure in order toextend its usable life. Once the extent of damage is known, appropriate
measures for repairing that damage can be carried out. A repair method
must satisfy two major goals: restore loss of strength and maintainmember/structural durability and fire protection. Typically, this involves theremoval of damaged concrete and casting of a patching material. However,this method generates large amounts of waste and consumes resources. A
repair method utilizing the re-curing of fire-damaged concrete would
optimize the life cycle potential of the material itself, which increases theperformance of the structural members and thus the structure as a whole. If
re-curing could achieve the two goals mentioned before, then it could be
utilized as a repair method which not only restored structural performance,
but reduced waste generation and material consumption, as well as utilized
the full potential of the concrete material itself. Past research has indicatedthat fire-damaged concrete has the potential for re-curing by the supply ofwater, which initiates rehydration of dehydrated cement and regrowth of thepore structure. However, the various factors which affect the strength loss
and subsequent recovery have not been fully explained.
This research observed the strength recovery potential of fire-damaged
mortar under different re-curing conditions. Changes in the microstructure
were also observed and related to the changes in strength. Resolving thedifferences between changes in strength and pore structure allowed for theunderstanding of the effect of re-curing condition on strength loss andrecovery.

2. EXPERIMENTAL PROCEDURE
2.1

Materials

Three cement mortar mixes were used in this research (Table 1):
normal-strength (NS), high-strength (HS), and steel fiber-reinforced (S6).
The water-cement (W/C) and sand-cement (S/C) ratios varied between the
NS and HS series; the S6 series used the same mix ratios as the HS series
but changed the air-entraining (AE) agent and high-range water-reducing
admixture (HRWA) volumes to achieve acceptable workability properties.
Steel fibers, with a diameter of 0.6 mm and length of 30 mm, were
provided by the Bridgestone Corporation (product number 30/.60CX).
The furnace capacity limited the specimen size to 50Ø×100 mm
cylinders. After casting, specimens were sealed and cured in the molds for

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three days and then demolded and placed in a water curing tank until two
weeks from casting, when they were moved to air curing at 60% relative
humidity (RH) and 20°C. High-temperature exposure was performed 28
days from casting.

W/C

S/C

AE

HRWA

NS

0.5

2.3

0.2

-

Steel
Fiber
(%vol)
-

HS

0.3

1.8

0.4

1.5

-

S6

0.3

1.8

0.4

2.5

0.6

Mix
Series2.2

Table 1: Mix Proportions
Mix Ratios (by mass)
Admixtures (%C)

High-temperature exposure

Fire damage was simulated by exposing the mortar specimens to hightemperature in an electric furnace. The exposure temperature was set at
550°C because this temperature was found to induce the highest amount ofdamage without explosive spalling for the W/C ratio and specimen size andshape used in this research. A two-hour exposure time was selected basedon observation of the effect of time on residual strength.
2.3

Re-curing conditions

After removal from the furnace, specimens were placed into one oftwo cooling conditions: air (60% RH, 20°C) or water (water-saturated,20°C). After one hour in these cooling conditions, specimens were moved to
the re-curing phase in the same two conditions (air and water). However,some specimens were moved from air cooling to water re-curing, resulting
in three total re-curing conditions: air, air-water, and water (Figure 1).
Testing of properties was performed before heating, after cooling (one hour),and after three and 28 days re-curing.

Figure 1: Flow chart for re-curing and testing

Influence of Re-Curing Condition on Damage and Recovery of Mortar Exposed to Fire

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2.4

Physical tests

The damage and recovery of the mortar specimens was measured on
two scales: load-carrying capacity (compressive strength) and micro
structure (Mercury Intrusion Porosimetry, or MIP). Compressive strength
was reported as absolute and residual compressive strength. Residual
strength is the ratio of the exposed strength to the unexposed strength(equation 1), and allows comparison between mixes by normalizing thestrength. The average values were taken from three specimens.
R = f / fo × 100 (%)(1)

Where R: residual strength rate (%), f: average exposed strength(MPa), fo: average unexposed strength (MPa).
MIP was utilized to observe the changes in total porosity due toheating and re-curing. MIP specimens were taken from the mortar cylinders
after compression testing.

3. RESULTS
3.1

Strength loss & recovery behavior

The residual compressive strength results, calculated per (equation 1),
and the strength loss and recovery percentage are shown by re-curingcondition (Figure 2). All series exhibit a general similar trend. For air recured specimens, most strength loss occurs by day 3, with no or little change
to 28 days. Water re-cured specimens lose a large amount of strength after 1
hour of water cooling, but show consistent strength recovery up to 28 days.
Air-water specimens lose strength during 1 hour of air cooling, but thenrecover strength during water re-curing similar to water re-cured specimens.
Air-water specimens show the highest strength at 28 days for all series,
followed by water re-cured specimens, then air re-cured specimens.
It can be seen that the S6 series exhibited the highest final residual
strength for all re-curing conditions – 63.6% (air), 77.6% (water), 94.5%(air-water) – followed by the HS series. NS series exhibited the lowest
residual strength rates. Strength loss was greatest for the water re-cured
specimens at 61.5% for HS and 56.6% for S6, except in the case of the NS
series. For the NS series, the formation of large surface cracks during the air
re-curing period contributed to a 75.6% decrease in strength. The least
amount of strength loss was observed for the air-water re-curing condition:
43.1% (NS), 29.5% (HS), and 17.6% (S6). Strength recovery was highest
for water re-curing – 30.6% for NS, 33.9% for HS, and 34.2% for S6 – andlowest for air re-curing.
The highest final residual strengths were observed for the air-water recuring condition. Air-water re-cured specimens suffered the least amount ofstrength loss, and only a moderate amount of strength recovery, yet the204

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100
80
60
40
20

NS
HS
S6

AIR

0
1 hour afterfire

3 days recuring

AIR
80

NS
HS
S6

60
40
20
0

28 days recuring

100

LOSS

RECOVERY

60
40

NS
HS
S6

20

WATER
1 hour afterfire

3 days recuring

Strength Change (%)

100

80

0

Strength Change (%)

100

100

WATER
80

NS
HS
S6

60
40
20
0

28 days recuring

LOSS

RECOVERY

100

80
60
40
20

AIR-WATER

NS
HS
S6

Strength Change (%)

Residual Compressive Strength (%)

Residual Compressive Strength (%)

Residual Compressive Strength (%)

combination of air cooling and water re-curing resulted in the highest
residual strengths. This would indicate that damage prevention has a greater
impact on final residual strength than strength recovery.

AIR-WATER
80

NS
HS
S6

60
40
20

0
1 hour afterfire

3 days recuring

28 days recuring

0
LOSS

RECOVERY

Figure 2: Air, water, and air-water residual strength results
3.2

Strength & porosity comparison

In order to determine the sources of strength loss and recovery in firedamaged mortar, porosity was measured and the behavior was compared tothe strength change behavior for the HS series (Figure 3). As an increase instrength typically corresponds to a decrease in porosity, and vice versa, any
deviations in this pattern would indicate outside factors affecting thestrength change behavior.
It can be seen that there are three locations where the strength andporosity behavior deviate significantly. For the air re-cured series, thestrength between 1 hour and 3 days decreases significantly, but the porosity

Influence of Re-Curing Condition on Damage and Recovery of Mortar Exposed to Fire

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December 2007, Dhaka, Bangladesh

120

0.00

100

0.05

80

0.10

60

0.15

40

0.20

20

0.25

Porosity (ml/ml)

Compressive Strength (MPa)remains constant. For the water re-cured series, the strength after 1 hour ismuch lower than that for the air re-cured series, but the porosity is relatively
similar. Finally, for the air-water re-cured series, the strength between 1hour and 3 days remains constant but the porosity decreases.

0.30

0Before fire

1 hour after fire 3 days re-curing 28 days re-curing

Strength, airStrength, water

Strength. air-water

Porosity, air

Porosity, water

Porosity, air-water

Figure 3: HS series strength and porosity comparison

4. MECHANISM
4.1

Strength loss mechanism

In order to resolve the differences between the strength and porosity
behavior as shown previously (Figure 3), it is necessary to consider thedifferences in cooling and re-curing conditions.
Air- and water-cooled specimens shared a similar decrease in porosity
after 1 hour of cooling. Furthermore, as the deterioration of the cement pastedue to heating is assumed to be the same as the exposure conditions were
the same, the difference in strength must be a function of the coolingcondition. For specimens cooled in the air, the cooling is by convection
processes, which results in a gradual decrease in temperature. Specimens
which were cooled by submersion in water after removal from heating
undergo a much more rapid decrease in temperature and “quenching,”
which, it is believed, results in the formation of imperfections in the form of
micro cracks. Therefore, the difference in strength after 1 hour of cooling is
caused by the damage to the matrix from micro cracks caused by quenching.
For air re-cured specimens, strength loss was observed to occur
between 1 hour and 3 days. It was found that specimens re-cured in the air
suffered large surface cracks during this time period (Figure 4). NS series
specimens showed the largest surface cracks. Surface cracking also occurred
on HS and S6 specimens, but the crack widths were much smaller. The

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severity of surface cracking corresponded to the relative level of strength
loss across the three series under the air re-curing condition. Furthermore,
porosity remained constant over that time period, indicating that the strength
loss must be caused by a different source.

NS

HS

S6
Figure 4: Surface cracking of NS, HS, and S6 air re-cured specimens
The formation of surface cracks is caused by the convection coolingprocess. As the specimen cools, a thermal gradient is formed due to thegradual temperature loss, which results in the outer part of the specimen
losing heat more quickly than the inner part. Differential thermal shrinkage
occurs as the difference in temperature across the specimen increases,
resulting in the formation of surface cracks.
4.2

Strength recovery mechanism

Strength recovery is driven by the supply of water to the damaged
mortar. For air re-cured specimens, the water supply is very low, as the
specimen is being re-cured in a 60% RH environment. Therefore, thestrength recovery behavior is very small.
For the water and air-water re-cured series, the re-curing condition –water submersion – is the same after the 1-hour cooling period. However,
the amount of strength recovery is greater for water re-cured specimens. The
difference in this strength recovery behavior is due to the initial coolingcondition. For the water re-cured series, specimens are removed from the

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furnace and immediately placed into room-temperature water. Therefore,
the temperature difference between the specimen and the water is very high,so water is sucked into the pore structure as part of the cooling process. Thiswater helps speed up the strength recovery process by shortening the timerequired for water to penetrate into the pore structure. Air-water specimens
are cooled in the air for an hour before placement in water, so thetemperature difference between the specimen and the water is much lower.
This has the dual effect of reducing the amount of damage done by“quenching,” as the thermal shock is much lower due to the lower
temperature difference, as well as reducing the amount of water sucked into
the pore structure. Therefore, the strength recovery process is slowed by thedamage due to thermal shock as well as the lower water supply.

5. CONCLUSIONSThis research attempted to gauge the potential for strength recovery of firedamaged mortar and determine the sources of damage by placing thespecimens in different cooling and re-curing conditions. Air and waterconditions were used to test the effects of thermal conductivity (thermal
shock) and water supply in order to view the recovery of strength. Pore
structure was also measured under these conditions, as density and strength
are related.
It was found that strength loss by cooling was caused by two
mechanisms: micro cracking, due to immediate submersion in water after
heating, and surface cracking, due to differential thermal shrinkage undergradual cooling. Specimens which were cooled in the air for 1 hour but thenplaced into water re-curing, before the formation of surface cracks, had thelowest strength loss as the damaging conditions of the other two re-curingconditions were avoided. Strength recovery under water supply wasobserved for both water and air-water re-cured specimens, but thequenching effect, which caused strength loss, also resulted in speeding up
the recovery process by supplying water quickly to the pore structure.
Applying the damage mechanisms by re-curing conditions could resolve thedifference in strength and porosity behavior.

REFERENCES
Tovey, A.K., 1986. Assessment and Repair of Fire-Damaged Concrete
Structures – an Update. ACI Special Publication 92: Evaluation andRepair of Fire Damage to Concrete, 47-62.
Taylor, H.F.W., 1990. Cement Chemistry, Academic Press Limited, London.
Poon, Chi-Sun, Azhar, Salman, Anson, Mike, Wong, Yuk-Lung, 2001.
Strength and Durability Recovery of Fire-Damaged Concrete after
Post-Fire-Curing, Cement and Concrete Research 31, 1307-1318.
Lin, Wei-Ming, Lin, T.D., Powers-Couche, L.J., 1996. Microstructure ofFire-Damaged Concrete, ACI Materials Journal Vol. 93, No. 3, 199205

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Georgali, B., and Tsakiridis, P.E., 2005. Microstructure of Fire-Damaged
Concrete: A Case Study, Cement and Concrete Composites, Vol. 27,
Issue 2, 255-259

Influence of Re-Curing Condition on Damage and Recovery of Mortar Exposed to Fire

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STRATEGIC MAINTENANCE OF PORTAND HARBOR CONCRETE STRUCTURESBASED ON LIFE-CYCLE MANAGEMENTHIROSHI YOKOTA
MITSUYASU IWANAMI, TORU YAMAJI, EMA KATO
Port and Airport Research Institute, Yokosuka, Japanhiroy@pari.go.jp
ABSTRACTPort and harbor structures have to keep structural performance overrequired levels in harsh marine environments. This can be achieved bothwith sufficient durability design and maintenance work based on theconcept of life-cycle management. Focusing on a reinforced concrete
superstructure of open-type wharf, this paper presents the methodologies ofrational and efficient maintenance work based on maintenance strategies
formulated in relation to durability design.

1. INTRODUCTION
The life of port and harbor structure is rather long. A structure designed
today must be expected to meet demands during its lifetime that cannot be
foreseen. At the initial design of a structure, designers must have several
assumptions, in which probably worst conditions are considered, so that thestructure can keep its structural performance over required levels. However,a number of existing structures unfortunately require remedial action
including repair and strengthening due to loss in structural capacities as aresult of chloride-induced corrosion of reinforcement embedded into
concrete. This may be caused by insufficient durability design with
optimistic assumptions against materials deterioration and by lack of proper
maintenance work after construction of the structure. To meet these facts,
strategic maintenance is the only way to be taken in relation to the result of
initial durability design. To realize the strategic maintenance, thecomprehensive life-cycle management is one of the key technologies.
The life-cycle management is a series of actions to evaluate the gradeof deterioration and structural performance degradation by inspection, to
predict the future progress of performance degradation, and to propose thealternatives of appropriate remedial action based on life-cycle cost
minimization or performance maximization under budget capping. The
authors have tried to establish the life-cycle management system for areinforced concrete superstructure of open-type wharf that is one of the mostvulnerable structures in ports and harbors. This paper introduces themethodologies of rational and efficient maintenance work based on
maintenance strategies formulated in relation to durability design.

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December 2007, Dhaka, Bangladesh
Design Standard

Design CodeRegulation
Standard

Maintenance Manual

Lifecycle Management

MaintenanceInstruction andMethodRole, Function,
Activity
Importance ofstructure
Lifecycle cost, Life
scenario

Maintenance
Code

Inspection Guideline

conformity

Regulation
Standard

Repair Manual

conformity

Maintenance
Plan

DB

Figure 1: Collaboration between durability design and maintenance work

2. MAINTENANCE STRATEGY
It is usually very hard to keep structural performance of a port and harbor
concrete structure over required levels for the whole service life because itis exposed to marine environments with rich chloride ion supply. Therefore,
sufficient durability design has to be employed at the initial design stage, inwhich some kinds of mitigating measures are needed. One simple measurethat anyone can realize is to increase concrete cover, but it seems distantbecause a concrete cover of about 200 mm or even larger is required.
Instead of taking actions only by means of durability design, maintenancework during service period should be collaborated to ensure the structural
performance. Figure 1 shows the collaboration system between durability
design and maintenance work before and after construction of structure,
respectively. With both durability performance verification at the design
stage and performance assessment at the maintenance work, the structure
can keep its structural performance over the requirements.
For realizing rational and effective maintenance work, a maintenancestrategy should be properly formulated during the durability design ofstructure before construction or after regular inspection for already existing
structure. Importance and substitutability of structure and difficulty ofmaintenance work should be well taken into account for the strategy-making.
Figure 2 shows three maintenance strategies indicating basic concepts of
how structural performance will be guaranteed beyond the performance
limit or the maintenance limit. Strategy I is defined that the structural
performance is always kept above the maintenance limit during the design
working life. This strategy is realized by use of highly durable materials
and/or preventive measures. Examples of durable materials and measuresare epoxy-coated reinforcement, highly durable permanent formwork,
extremely high quality concrete such as UFC, etc. Maintenance work in thisstrategy is not ignorable even serious deterioration is not expected to occur.
Instead, the maintenance is required on the regular-basis including careful

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monitoring to avoid unexpected deterioration. Strategy II is defined thateven performance degradation is expected in the design stage, minor
remedial actions are repeatedly applied before the maintenance limit isreached. In Strategy II, it is necessary to predict the progress of deteriorationand draw up a maintenance plan based on the result of prediction.
Maintenance in this category allows performance degradation due todeterioration at the design stage, but minor remedial action should be taken
as early as possible when deterioration exposes. Strategy III is a kind of
corrective maintenance, in which performance degradation is allowed tooccur but major remedial actions may be applied once or twice for
performance recovery.
Since an open-type wharf is expected to be highly safe and serviceable
during performing cargo-handling work, its main performance requirements
are safety and serviceability. It is, therefore, preferable to adopt Strategy I or
II for the maintenance of a superstructure of open-type wharf.
Initial

Initial

InitialLimit of maintenance
Limit of maintenance
Limit of performance

Limit of performance

Limit ofperformance

In-service period

In-service period

In-service period(a) Strategy I(b) Strategy II(c) Strategy III

Figure 2: Definition of three maintenance strategies

3. LIFE-CYCLE MANAGEMENT
3.1

Overall concept

The maintenance work is carried out to assess the present conditionsof structure and to quantify the level of structural performance. In addition,by predicting future progress of performance degradation, the mostappropriate method of remedial action is chosen for minimizing the lifecycle cost or maximizing structural performance recovery under budget
capping. A general procedure of maintenance work is shown in Figure 3,
which is based on the life-cycle management (LCM) concept. The life-cycle
management system is composed of the following five main components:
•
•
•
•
•

Inspection of the present conditions of structural members
Assessment of structural performance
Prediction of future progress of performance degradation
Proposal of method and timing of remedial action
Decision of action among proposed alternatives

Strategic Maintenance of Port and Harbor Concrete Structures Based on Life-Cycle Management213

December 2007, Dhaka, Bangladesh

Maintenance plan
Service period
Usage

Periodicinspection

Input/ Reference

DesignEnvironment

Assessment and Prediction
Database

Performance
Input/Reference・Inspection
・Prediction

Present

・Intervention

Time

Service life
Future plan

Method and timing of action

Input/ Reference

LCM system

Reduce LCCand realize rational maintenance

Figure 3: Procedure of life-cycle management
3.2

Judgment of deterioration

Judgment of deterioration is made by a two-step inspection system asshown in Figure 4; namely, primary inspection and detailed inspection. The
state of deterioration is visually evaluated and judged using the deterioration
grade: Grade d to a according to the general grading criteria in themaintenance manual for port and harbor structures (Port and Airport
Research Institute, 2007). Grade d refers to a sound condition without any
signs of deterioration, while Grade a is the most severe deterioration state.
For example, the criteria of judgment for a reinforced concrete
superstructure of open-type wharf are summarized in Table 1. For proper
judgment, inspection should be carried at with regular intervals. At the
moment, the standard time interval is set at 2 years.
Visual inspection

Assessment

Primary inspection
Inspection andevaluation visuallyfocusing on structuralelements and parts

Visual inspection, NDT, test, etc.

Evaluation for an entire
structure

Detailed inspection
Detailed inspection and evaluation
usingspecial techniques

Figure 4: Process of assessment
When the primary inspection is insufficient to provide proper data forassessment, the detailed inspection is carried out. The detailed inspection
includes visual inspection by well-trained divers for submerged parts,
measurement with non-destructive or destructive techniques, etc. After the
onset of corrosion of reinforcement, structural performance will be degradedvery rapidly. Therefore, material deterioration should be captured before its

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appearance on the surface of member. For this purpose, non-destructive
techniques are of use. However, before their application, the effectivenessand accuracy should be well examined under real environmental conditions.
Table 1: Grade of deterioration of wharf superstructure
Item

MethodCracking,delamination,and spalling

Visual inspection
on cracks, surface
appearance etc.

Corrosion ofreinforcement

Visual inspection
on corrosion andrust stain

a

3.3

b
c
d
a
b
c
d

Judgment criteria
Widely extended spalling off of concrete cover orcracks of 3 mm or wider
Partially spalling off of concrete cover or many
corrosion cracks
Some corrosion cracks or partial delamination
Nothing observed
Broken reinforcement, directly exposed
reinforcement, or heavy rust stain
Much rust stain
Partially extended rust stain
Nothing observed

Assessment

It is required to quantitatively make overall assessment of a structurefrom the viewpoint of structural performance. The visual inspection is only
able to provide the change in appearance of structural member, but
structural performance has to be evaluated as precisely as possible.
The relationship between structural performance (structural capacity)and the grade of deterioration is shown in Figure 5. This figure was obtainedby loading tests on reinforced concrete beams prepared for exposure tests
for more than 20 years and extracted slabs from real structures which had
been in service for more than 30 years (Yokota, et al., 2006a). When thedeterioration grade reaches Grade b, structural performance tends to become
lower than the design requirement level. These facts are well considered forthe overall assessment from the viewpoint of structural performance.

Structural capacity(vsdesign calculation)

2.0

1.5

1.0

0.5

Real member
Specimen

0.0
d

c
b
Grade of deteriorationa

Figure 5: Structural capacity vs. grade of deterioration

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December 2007, Dhaka, Bangladesh

3.4

Prediction

Since deterioration of a reinforced concrete member is induced andaccelerated by chloride ion provided by sea water, the chloride ion profile
inside concrete and the volume loss of reinforcement are predicted as mainindices for durability performance. The calculation theory based on Fick’s
second law of diffusion of chloride ion in concrete has been widely used forthe prediction of deterioration progress. For simulating the diffusion ofchloride ion in concrete with this theory, it is necessary to quantify threefundamental parameters: chloride ion content on the surface of concrete, C0,
an apparent diffusion coefficient of chloride ion in concrete, Dap, and theconcrete cover depth, c. C0 represents the environmental condition aroundstructural members and Dap represents the diffusivity of chloride ion in
concrete depending on the quality of concrete particularly on the type of
cement and the water-to-cement ratio. When the chloride ion content
reaches a threshold value at the position of reinforcement, corrosion ofreinforcement will start and progress rapidly. The threshold value for onsetof reinforcement corrosion is specified to be 2.0 kg/m3 for a superstructureof open-type wharf. This is based on experimental test results as shown in
Figure 6 (Yamaji, et al., 2001).
100

Corroded area (%)

80
2.0
60
40
Cover
20 mm
40
70

20
0
0

5
10
Chloride ion content (kg/m3)

15

Figure 6: Threshold chloride ion content to initiate rebar corrosion
As the progress of deterioration of a structure differs widely by its
location because of inhomogeneous characteristics of materials anddiversity of environmental conditions, the proper determination of C0 and
Dap is not so easy. An example of wide variations of values C0 and Dap in
one reinforced concrete slab of open-type wharf is shown in Figure 7(Yokota, 2006). They were obtained for concrete cores taken out from one
slab of almost 1.5 m square. In the figure, the rectangular box shows thearea indicating the range of μ±1σ (μ : average value and σ : standard
deviation). The figure does not show the correlation between the averagevalue and the standard deviation. The slab shows that the proportion of
measured results inside the box is only about 50 %. In the practicalinvestigation of existing structures subjected to marine environments,
chloride ion profile of concrete has generally been estimated according to216

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one or a few sampled concrete. However, it seems that such a few numbersof concrete cores may not be representative.
The fact indicates that it is practically rather difficult to accurately
predict the progress of deterioration and remaining structural capacities byusing the diffusion theory. Instead of this, the authors have tried toinvestigate the applicability of a calculation model to predicting the progressof deterioration by analyzing the variation of visually observed deterioration
grades with the Markovian chain model (Yokota, et al., 2006b). Thisapproach is of use to understand the overall tendency of deterioration inconsideration of its variation by the experienced progress of deterioration. In
the model, the state and the transition are main components, and aprobability of shifting from a certain state to the next state is expressed by atransition probability. A structural member (slab or beam) belongs to acertain grade of deterioration; the present grade of deterioration shifts to thenext grade in a time step with a certain transition probability while the otherstructural members remain in the present deterioration grade with theremaining probability. When a transition probability is determined withgood accuracy, the overall trend of future deterioration can be predicted.
The example of application is shown in Figure 8. This figure shows
collected data from all the structural members in a specific port, in which
the transition probability is obtained through fitting the actual distribution
and simulated distribution. Based on the prediction result after 15 years, thenumber of members probably judged as Grade a may increase up to about 3
times.
For the application of the Markovian chain model to prediction, many
data should be collected and accumulated for members under almost thesame environmental and material/structural conditions.

Surface chloride ioncontent (kg/m3)

20

μ ± 1σ

15
10
5
0
0

1

2

3

Apparent diffusion coefficient(cm2/year)

Figure 7: Variability of C0 and Dap within one slab

Strategic Maintenance of Port and Harbor Concrete Structures Based on Life-Cycle Management217

Number of members

December 2007, Dhaka, Bangladesh
180
160
140
120
100
80
60
40
20
0

Present
Model
PredictiondcbGrade of deteriorationa

Figure 8: Prediction by Markovian chain model

4. LIFE-CYCLE COST ESTIMATION
To determine the maintenance strategy or to consider the appropriate timing
and method of remedial action, estimation of life-cycle cost (LCC) is one of
the best indices. LCC is calculated for several maintenance scenarios among
maintenance strategies as mentioned earlier. In the calculation, the initialcost, maintenance cost including inspection cost, and the cost of planned
remedial action are totaled.
An example of estimated LCC is shown in Figure 9 (Japan Society of
Civil Engineers, 2007). In Strategy II, all concrete surfaces of slabs andbeams are coated, and they are re-coated at the end of the life of the coating
material (assumed to be 10 years in this figure). In Strategy III, the timing of
repair is deferred as much as possible. When the second half of theacceleration period begins 25 years after the completion of the structure,
section repair and surface coating are carried out extensively for the
relatively deteriorated parts of the structure. It is assumed that the crosssections of 95% of all members are section-repaired. LCC thus calculated isexpressed in terms of the ratio to the initial construction cost in the case thata general reinforced concrete superstructure within Strategy III isconstructed. The social discount rate is not taken into account in thecalculation.
At the end of design working life (50 years in this calculation),
Strategy I has the smallest LCC even its initial cost is largest. It should be
confirmed here that the more durable structure in construction, the lower
LCC achieved. Since Strategy I is not likely to cause deterioration resulting
in performance degradation and only primary inspection is needed, LCC at
50 years after construction is not significantly higher than the original
construction cost. For the scenario considered in Strategy II, one option is tocarry out coating at the beginning of construction because deterioration of
structures exposed to severe environmental conditions is very fast. It should
be noted that this scenario based on Strategy III shows the largest LCC andthe amount of incremental increase in cost is so large that single-year costs
are far larger than those for the other two scenarios.

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7
Strategy I
Strategy II
Strategy III

Normalized LCC

6
5
4
3
2
1
0
0

10

20

30

40

50

In-service period (year)

Figure 9: Example of LCC estimation for 50 years
LCC is calculated based on various assumptions, but it provides
important information needed for making decisions about the future
direction of maintenance. An advantage of Strategy II is that the accuracy of
the initial deterioration estimation can be checked during the maintenanceprocess so that they can be modified to more realistic predictions. Anotheradvantage is that maintenance cost can be equalized more or less because
necessary funds can be prepared in advance. Strategy III should be avoided
from the viewpoint of LCC. If neither Strategy I nor Strategy II can be used
for some reason, it is necessary to draw up funding and technical plans inadvance. In Strategy III particularly, various problems may arise with theprogress of deterioration, affecting the conditions under which the structure
is to be used. It is, therefore, necessary to determine the best timing fortaking measures through regular inspections.
LCC calculated here can be a useful indicator by which an appropriate
scenario can be selected according to the determined maintenance strategy.
Durability verification results obtainable at the design stage, however, havelarge safety margins because of considerable variability at the design stage.
A deterioration investigation of open-type wharf, for example, showed thatin many cases the corrosion of reinforcement did not occur even whenchloride ions accumulate far exceeding the threshold chloride ion
concentration. It is necessary, therefore, to draw up maintenance plans withfull understanding of this variability and assumption of deterioration
predictions. It is essential to take proper maintenance measures during theservice life of the structure instead of unquestionably believing the estimates.

5. CONCLUDING REMARKSThe life-cycle management system including prediction of the progress ofdeterioration was developed and being implemented for maintenance of port
and harbor structures in Japan. After modification of the original system, theauthors expect that rational and effective maintenance is realized so that
LCC reduction and performance maximization can be attained.

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December 2007, Dhaka, Bangladesh

REFERENCES
Japan Society of Civil Engineers, 2007. Example of Design
Calculations Based on JSCE Standard Specifications for Concrete
Structures. JSCE Guidelines for Concrete, No.10.
Port and Airport Research Institute, 2007. Manual on Maintenanceand Rehabilitation of Port and Harbor Facilities, Coastal Development
Institute of Technology, in Japanese.
Yamaji, T., Mohammed, T. U., Aoyama, T., and Hamada, H., 2001.
Effects of Exposure Environment and Cement Types on Durability ofMarine Concrete, Proceedings of the Japan Concrete Institute, Vol.23, No.2,
577-582, in Japanese.
Yokota, H., 2006. Variability in Chloride-Induced Deterioration ofMarine Concrete Structures, Proceedings of International Seminar on
Durability and Lifecycle Evaluation of Concrete Structures-2006,
Hiroshima, 41-50.
Yokota, H., Iwanami, M., Kato, E. and Takahashi, H., 2006a.
Prediction of Performance Degradation of RC Members Due to ChlorideInduced Deterioration, Proceedings of the 10th East Asia-PacificConference on Structural Engineering & Construction (EASEC-10),
Bangkok, 493-498.
Yokota, H., Komure, K., and Takahashi, H., 2006b. Lifecycle
Management of Concrete Deck by Markov Model. Lifetime Engineering ofCivil Infrastructure, Edited by Miyamoto, A. et al., 137-149

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VARIATION OF CORROSION
CHARACTERIZATION OF REINFORCINGBAR IN EXISTING RC STRUCTURE
EMA KATO1, MITSUYASU IWANAMI2, HIROSHI YOKOTA3Port and Airport Research Institute, Japankatoh-e@pari.go.jp
TAKUMI SHIMOMURA
Nagaoka University of Technology, Japan
ABSTRACT
It is important to characterize the corrosion profile of a reinforcing
bar embedded in concrete when it is suffered from chloride-induced
deterioration. In a real structural member, a reinforcing bar is not
uniformly corroded, which results in very wide variations in its crosssectional loss along its axial direction. The mechanical properties ofcorroded reinforcing bar may be affected by the wide variation. However,an actual corrosion profile has been rarely investigated in real structuresand information on the variation has been insufficiently accumulated.
In this paper, corrosion profiles of reinforcing bars were investigated
for real reinforced concrete slabs of open-type wharf that has been inservice under marine environment for 29 years. Through the tests andanalyses, the variation of corrosion characterizations and mechanicalproperties of corroded reinforcing bars are discussed.

1. INTRODUCTION
When reinforced concrete structures are located in coastal and offshore
areas, the most important deterioration phenomenon to which attention
should be paid in design and maintenance is corrosion of reinforcement
embedded into concrete. Corrosion of reinforcement can initiate cracks ofconcrete due to the volume expansion of corrosion products. Such cracks
may accelerate the further progress of corrosion, and subsequently structural
performance such as load carrying capacity and ductility will be deteriorated(Kato, et al., 2006). However, the relationship between the degree ofcorrosion of reinforcement and structural performance of concrete members
has not yet been quantitatively evaluated. During regular maintenance workof harbor structures, generally, the appearances of concrete members arevisually observed and are subjectively evaluated based on the deterioration
grade specified in the manual (Port and Airport Research Institute, 2007).
Many researchers and engineers are now actively studying theremaining structural capacities and producing a lot of useful results on themwith testing artificially deteriorated reinforced concrete members. However,221

December 2007, Dhaka, Bangladesh

in a real structural member, a reinforcing bar is not uniformly corroded
compared with an artificially corroded one. Moreover, the mechanicalproperties of corroded reinforcing bar may be affected by the nonuniformity of corrosion.
In this paper, corrosion profiles of reinforcing bars were investigatedfor several real reinforced concrete slabs of an open-type wharf that has
been in service under marine environment for 29 years. Through the tests
and analyses, the variation of corrosion characterizations and mechanicalproperties of corroded reinforcing bars are discussed.

2. METHODS OF INVESTIGATION AND TEST
2.1

Outline of slabs extracted from RC deck of pierTwo slabs, slab A and Slab B, were extracted from an open-type
wharf located in the splash zone at Japan Sea. After service for 29 years,
they were replaced by new slabs because many cracks and delamination ofcover concrete were observed on the bottom surfaces. The details of thematerials used, such as the mix proportion of concrete and the strength ofreinforcing bars, are not available because of lack of design and execution
records. The two slabs were identical in their dimensions (300mm thick,
900mm wide, and 2000mm long). In each slab, two layers of round bars of
13mm in the diameter were embedded in the concrete. Average cover
thicknesses of both slabs are listed in Table 1. Figure 1 shows the surface
appearances of the bottoms and location of the bottom layer reinforcing bars.
Some cracks along the bottom layer reinforcing bars and some random
cracks were observed in slab A. In slab B, probably because of poor casting
work, there was a large honeycomb area. In other areas, corrosion cracks
along the steel bars and delamination of cover concrete were observed.
Average compressive strength of concrete was 42N/mm2, which was
obtained from test for concrete cylinders cored from non deterioration parts.
Symptoms relating to ASR deterioration were not observed in both slabs.
Table 1: Position of reinforcing bar from the bottom surface.
Location
Axis
Slab A
Slab B
Bottom layer
X
39
38
Y
53
54
Top layer
X
151
152
Y
146
157
(mm)

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Y
Slab A：Reinforcing bar (Y axis)

X：Crack：Delamination：Honeycomb

Y
Slab BX

Figure 1: Bottom surface of RC slabs

2.2

Method of investigation for corrosion property

2.2.1 Weight loss of steel bar
The bottom layer reinforcing bars were taken out from the slabs andtheir weight losses were measured with the following procedures: at first,
the bar was cut into small pieces with 100mm long and sand blasted toremove corrosion products and concrete sticking on its surface. Then, thepiece was immersed in 10% diammonium hydrogen citrate solution tocompletely remove corrosion products. The weight loss of piece wasobtained by comparing its weight with that of a non-corroded piece. If thecorrosion products were not observed on the surface of a piece, the piece
was considered to have no corrosion (weight loss=0.0%). The total numbersof piece were 265 in slab A, which were sampled from 8 reinforcing bars in
the longitudinal (X) direction and 13 bars in the transverse (Y) direction,and 249 in slab B, which were sampled from 7 bars in X direction and 13
bars in Y direction.
2.2.2 Distribution of cross-sectional area of steel bar
For a total of 27 pieces chosen at random, surface geometries were
measured using laser-scanning machine. Outline of the measurement isshown in Figure 2. The surface geometry measurement was conducted
separately for the lower and upper halves of piece. The measurement length
was 60mm. Measurement pitches were set at 0.5mm in the cross-sectional
direction and 1.0mm in the axial direction. Distribution of cross-sectional
area of each piece was obtained by integrating the laser irradiation distancesin the cross-sectional direction of lower and upper halves. The measured
cross-sectional area is probably not exactly the same as the real cross-

Variation of Corrosion Characterization of Reinforcing Bar in Existing RC Structure223

December 2007, Dhaka, Bangladesh

sectional area because the interference of the pit-hole corrosion. Figure 3
shows three examples of the distribution of cross-sectional area. Its nominal
cross-sectional area is 132.7mm2 if not corroded.
Laser

Measurement length 60mm
C
L

Upper half

Piece

Lower halfInterval 1.0mm

Interval
0.5mm

Cross-sectional area
(mm 2)

Figure 2: Outline of laser measurement
150

100
A ve. cross-sectional loss 0.1%
A ve. cross-sectional loss 3.3%
A ve. cross-sectional loss 7.5%

50
-30

-20
-10
0
10
20
Distance from the center (mm)30

Figure 3: Distribution of cross-sectional area
2.3

Measurements of mechanical properties of steel bar

The tension test was conducted to obtain yield and tensile strengths
and elongation of the piece after the cross-sectional area measurement.
Picture 1 shows the testing specimen prepared for the tension test. Two
deformed bars (SD295-D16) of 150mm long were welded to both ends ofthe piece with 20mm long lap. The total length of the piece for the tension
test was about 60mm. Targets for the elongation measurement were set tonear the end of the welding device as shown in Picture 1. Three pieces
which were failed by slipping out from the welding device were excluded
from the following discussion.

Picture 1: Testing specimen for tension test

3. CHARACTERIZATION OF REINFORCEMENT CORROSION
3.1

Variation of weight loss

Figures 4 and 5 show the distribution of the weight loss of bottom
layer reinforcing bar in slabs A and B, respectively. They were drawn withthe measured results of corresponding pieces. The directions of X and Y inthese figures are shown in Figure 1. In slab A, the maximum weight loss is

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observed in the cracked part along the longitudinal bar. Those cracks wereconsidered to accelerate the corrosion of reinforcing bars in Y axis. In slab
B, weight loss due to corrosion was remarkable in the honeycomb parts.
Figure 6 shows the relationship between cover depth and weight loss. In
addition, weight losses corresponding to the honeycomb parts were
excluded in the figure. Though the effect of crack on the corrosion ratecannot be ignored, the weight loss due to corrosion tended to decrease as thecover depth increases. This result agrees with the basis of durability designof RC structure. In addition, the previous research by Tsutsumi, et al. also
reported the same result (1996). Hence, it was reconfirmed that depth andquality of cover concrete played important roles in maintaining the
durability of RC structures.
Y axis bar

Ave. 1.3%
S.D. 4.3%

25

20-25
15-20
10-15
5-10
0-5

5

10

(mm)

950

0

650

x

127

350
426

1954

700
539
300
32 y

50

350

650

950

1250

1550

1850

0

(mm)

5

741

10

15

1048

15

Ave. 0.8%
S.D. 2.5%

20

1670

20

Weight loss (%)

Weight loss (%)

25

1352

X axis bar

50

y

x

0

0

Figure 4: Weight loss distribution in slab A
Y axis bar

20-25
15-20
10-15
5-10
0-5

Ave. 1.8%
S.D 3.5%

20
15
10
5

Ave. 1.0%
S.D. 2.1%

20

Weight loss (%)

X axis bar

25

Weight loss (%)

25
質量減少率 (%)

15
10
5

(mm)

(mm)
0

127

426

x

350
741

1048

1352

1954

650
1670

781
540
320
43
y

50

350

650

950

1250

1550

1850

0

50 y

x

0

0

Figure 5: Weight loss distribution in slab B
slab A
slab B

Weight loss (%)

25
20
15
10
5
0
20

30

40

50

60

70

Cover depth (mm)Figure 6: Cover depth vs. weight loss

Variation of Corrosion Characterization of Reinforcing Bar in Existing RC Structure225

December 2007, Dhaka, Bangladesh

3.2

Variation of cross-sectional loss

Figure 7 shows the relationship between average cross-sectional lossesof piece in lower and upper halves of the bottom layer reinforcing bar. The
average cross-sectional loss in the lower half was larger than that in theupper half. This was considerably caused by the influence of the interfacialtransition zone formed due to bleeding.
Figure 8 shows the relationship between average and maximum crosssectional losses. Based on the linear approximation, the maximum crosssectional loss was 2.3 times of the average one. This value was slightly
larger than that reported in the previous research by Ooyado, et. al (2005).
The difference is considered to be caused by the differences in the corrosion
methods and the surface geometries of reinforcing bar.

Upper hal ｆ cross-sectional loss(%)

Figure 9 shows the relationship between the average cross-sectionalloss and the coefficient of variation in cross-sectional area. The coefficientof variation becomes large as the average cross-sectional loss increases.

15
10
5
0
0

5

10

15

Lower hal ｆ cros s-s ectional los s (%)

Max. cross-sectional loss (%)

Figure 7: Cross-sectional loss in lower and upper halves of pieces

2015

y=2.31xR2 = 0.85

10

Ooyado

5
0
0

2

4

6

8

10

Ave. cros s s ectional los s (% )Figure 8: Average and maximum cross-sectional losses

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S.D / Ave （ % ）

5
4
3
2
1
0
0

2

4
6
8
Ave. cross- sectional loss (%)

10

Figure 9: Variation of cross-sectional losses

4. INFLUENCE OF CORROSION ON MECHANICALPROPERTIES
Mechanical properties of corroded reinforcing bars were usually evaluatedby the weight loss because of its easiness for measurement. However, theweight loss was considered to be insufficient as a corrosion index because
the surface geometry of corroded reinforcing bar was varied as shown in
Figure 3. In this study, mechanical properties of corroded reinforcing bar
were examined with consideration of the variation in cross-sectional loss.

Load / Min. cross-section area
(N/mm 2)

Figure 10 shows the relationship between average cross-sectional loss
and yield and tensile strengths of piece. Yield and tensile strengths were
calculated by dividing yield and tensile loads by the minimum crosssectional area; in other words, the maximum cross-sectional loss. Straightand broken lines show approximations obtained by the least square method
and the range of ±20% from the approximate value respectively. Because
the theoretical strength of reinforcing bar does not depend on its crosssectional area, the inclinations of approximate lines are considered to be 0.

600
500
400
300
200
Yeild s trength

Tens ile s trength

100
0

2

4

6

8

10

Ave. cros s -sectional los s (%)

Figure10: Average cross-sectional loss vs. strengths

Variation of Corrosion Characterization of Reinforcing Bar in Existing RC Structure227

December 2007, Dhaka, Bangladesh

Figures 11 and 12 show the relationships between average andmaximum cross-sectional losses and elongation, respectively. In Figure 11,
the relationship between average weight loss and elongation reported by
Kobayashi (2006) was also presented. The elongation became small as the
cross-sectional loss increases, and the effect of corrosion on the elongation
was larger than that on the strengths. Kobayashi (2006) also reported thesame conclusion. However, the relationship between cross-sectional loss
and elongation was more widely distributed compared with that between
cross-sectional loss and strength.

Elongation (% )

30
20
10
Kobayashi

0
0

5
10
15
Ave. cros s -s ectional los s (% )20

Figure11: Average cross-sectional loss vs. elongation

Elongation(%)

30
20
10
0
0

5
10
15
Max. cros s -s ectional los s (%)

20

Figure12: Maximum cross-sectional loss vs. elongation
Picture 2 shows the cross-sections at breaking location. In the case ofsound piece, because the cross-section was not lopsided, the tensile stress
was considered to distribute uniformly on the cross-section. On the other
hand, the cross-section of corroded piece was asymmetry even though thecross-sectional loss was small. According to the previous research on
fatigue property of corroded reinforcing bar by Moriwake, et al. (1996),
uneven cross-section due to corrosion caused a crack under fatigue stress,and consequently, the progress of that crack greatly influenced on thefatigue property. Though the way of current loading test was different fromfatigue test, the lopsided stress seemed to have effects on the yield andtensile strengths and elongation. Therefore, the mechanical properties ofcorroded reinforcing bar are significantly affected by the unevenness ofcross-sectional area. In this study, the cross-sectional loss in the lower halfof piece was larger than that in upper half as mentioned in 3.2. This fact wasconsidered to affect the yield and tensile strengths. Moreover, because this228

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effect considerably became large after yielding, as a result, the variation of
the elongation was relatively large as shown in Figure 12.

Picture 2: Cross-section at breaking location

5.

CONCLUSIONS

1) The weight loss of reinforcing bar in slabs of open-type wharf showed
extremely large variations along the axis of bar.
2) The cross-sectional loss of the lower half of piece was larger than that of
the upper half because of the existence of the interfacial transition zone
formed due to bleeding.
3) Unevenness of cross-sectional loss had an influence on the mechanicalproperties of piece because of the lopsided action of tensile stress.

REFERENCES
Kato, E., Iwanami, M. and Yokota,H., 2006. Deterioration in ductilityof RC beams with corroded reinforcement, Proceedings of the 2nd
Fédération Internationale du Béton Congress, Naples.
Kobayashi, K., 2006. The seismic behaviour of RC member sufferingfrom chloride-induced corrosion, Proceedings of the 2nd Fédération
Internationale du Béton Congress, Naples.
Ooyado, M., et al., 2005. Evaluation of bending strength of corroded
reinforced concrete members, RTRI report 19(12), 4-9. (in Japanese)
Port and Airport Research Institute, 2007. Manual on maintenance andrehabilitation of port and harbour facitlities, Coastal Development Instituteof Technology. (in Japanese)
Tutsumi, T., et al., 1996. Evaluation on parameters of chloride
induced damage based on actual data in situ, Journal of Materials, Concrete
Structures and Pavement, 544(V-32), 33-41. (in Japanese)
Moriwake, A., et al., 1996. Estimation of fatigue life of reinforced
concrete members deteriorated by chloride attack, Proceeding of the Japan
Concrete Institute 18(2), 1529-1534. (in Japanese)

Variation of Corrosion Characterization of Reinforcing Bar in Existing RC Structure229

December 2007, Dhaka, Bangladesh

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EVALUATION OF THE SEISMIC
VULNERABILITY OF BANGLADESHIRC BUILDING USING NON-DESTRUCTIVETESTINGSYED ZILLUR RAHMAN1, MEHEDI AHMED ANSARY2,
MUNAZ AHMED NOOR3, RAJAN SAHA4
Department of Civil Engineering, BUET, Dhaka, Bangladesh
ansary@ce.buet.ac.bd
HISASHI KANADA1, MIHO YOSHIMURA2,KIMIRO MEGURO3, TAKETO UOMOTO4
ICUS, IIS, The University of Tokyo, Japan
ABSTRACT
Bangladesh has long been believed to be a country with medium
seismic hazard. But the practical design and analysis of buildings have notpaid attention to seismic aspects. However, in recent years many reliable
reports have revealed that Dhaka, the capital city of Bangladesh, has apotential risk from distant earthquakes to amplify the ground motion. For
this reason the seismic design and analysis of buildings cannot be neglectedany more. Nevertheless the dynamic properties of the buildings, which areimportant to seismic design and analysis, have been limitedly studied in
Bangladesh. The objective of the study was to assess the vulnerability of
Bangladeshi buildings using non-destructive testing, namely microtremor
measurements and Ferroscan. For this purpose, 18 reinforced concrete(RC) buildings were surveyed mainly within BUET campus. This paper
presents the information of surveyed buildings including findings ofreinforcement detailing and microtremor analysis of buildings. Using
Ferroscan, reinforcement diameter and location within the RC buildings
were detected. Microtremor measurements were used to determine thepredominant period of RC buildings.
Earthquake vulnerability of the surveyed buildings was assessed
based on: 1) the possibility of resonance in case of an earthquake, i.e.
whether the structure natural period was close to that of the soil; 2) the
construction quality, based on whether reinforcement arrangement andconcrete strength followed the design drawings; and 3) structural
irregularities, based on visual inspection. The natural period of somebuildings was found to be close to that of soil, so their seismic response may
be considerably amplified during an earthquake. Results obtained from
Ferroscan survey showed that the reinforcement did not match the design
detailing. Cover and spacing of lateral ties in columns and stirrups inbeams widely vary from design. Empirical correlation between number ofstory and natural period of buildings with RC frame was also proposed.

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1. INTRODUCTION
The aim of this study is to detect the earthquake vulnerability of
Bangladeshi RC buildings by means of determining the location of thereinforcement and their spacing and Microtremor observation. So there aremainly two parts of the study. They are••

Microtremor measurement
Detection of reinforcement

The importance of dynamic properties of buildings become paramountwhen seismic design of the buildings is considered. This is because theresponse of structures mainly depends on the characteristics of both
excitation forces and dynamic properties of buildings. In this regard, inorder to design and analyze the earthquake resistant buildings, it isnecessary to identify the dynamic properties of the buildings. For instance,
the fundamental frequency is employed to determine the site-structure
resonance factor in the base shear formula used in the static approach ofmany earthquake codes. In general, the approaches to the identification the
dynamic properties of buildings can be categorized into three main
approaches: (I) empirical, (2) numerical analysis, and (3) direct
measurement approaches. The empirical approach provides simplified
formulas for estimating the fundamental periods of buildings in terms ofgeometric dimensions of the buildings. The second approach, the numericalanalysis, is normally used during the design process. A finite element modelof the building, which consists of the mass and stiffness matrices of thesystem, is first formulated. Dynamic properties such as natural frequencies
and vibration mode shapes are obtained by the Eigen analysis. The third
approach is the direct measurement approach, which first measures dynamic
responses of existing buildings, and then identifies their dynamic properties
from the measured responses.
On the other hand, detection of reinforcement includes number ofreinforcement, spacing of reinforcement, and cover over the reinforcement
etc. Ferroscan is used to determine this reinforcement details. The
determination of reinforcement in RC building is very important forearthquake resistant. These buildings include academic buildings, residentialbuildings, schools, students’ dormitory and fire stations. Most buildings arewithin BUET campus in Dhaka, Bangladesh.

2. METHODOLOGY
To identify the dynamic properties of buildings, the empirical approach isnormally considered practical and widely used in a preliminary design
process. This is because it is convenient to estimate these properties bysimple empirical formulas, which are provided by building codes in seismic
provisions. However, empirical formulas, which are recommended in many
countries, are different because the required level of design force and thecharacteristics of building construction in different countries are different.

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As a result, the empirical formula based on the statistical data of measured
dynamic properties in one country may not be valid to another country.
Therefore, the numerical analysis approach, which normally uses a finite
element model, may be employed to solve this problem. Design engineers
have to incorporate all appropriate modeling assumptions to represent thereal behaviors of buildings in order to identify accurate dynamic properties.
In practice, many design engineers usually formulate the finite element
model of the buildings with structural members such as beam, column, andshear wall members and they normally assume that the foundations of thebuildings behave like a rigid foundation type (all degrees of freedom areconstrained at ground level of first floor columns). However, above
modeling, which considers only the structural members and the rigid
foundations, is not appropriate to identify the dynamic properties ofbuildings because the dynamic properties mainly depend on the total
stiffness of the buildings, which is also influenced by the stiffness of nonstructural members, and the flexibility of the foundations. In order to
identify correct dynamic properties, the most accurate approach is the direct
measurement approach because the properties are derived from actualdynamic response of existing buildings.
In recent years, several direct measurement techniques fordetermining the dynamic properties of structures have been developed.
These techniques can be categorized into three basic methods 1) forced
vibration method, 2) free vibration method, and 3) ambient vibration
method. Among these techniques the ambient vibration measurement is themost attractive option. The signal processing techniques can be categorized
into time domain and frequency domain techniques. In the time domain
technique, response-time history is employed directly in the identification of
dynamic properties of structures. While in the frequency domain technique,response-time history has to be firstly converted into frequency domain by
Fourier analysis. Dynamic properties are then extracted from the frequency
spectrum, which is the plotting of Fourier magnitude response against
frequencies. Although both techniques can be employed to identify the
dynamic properties of buildings, the frequency domain technique gives abetter physical interpretation than the time domain technique because it
presents the response of buildings in the form of the frequency spectrum.
This frequency spectrum can be used directly to identify natural frequencies
from the frequencies corresponding to the peak values of Fourier magnitudeand calculate vibration mode shapes from the spectral ratio method. In
addition, an algorithm in the time domain technique is more complicatedthan frequency domain technique, which provides the algorithm in the formof Fast Fourier Transform (FFT).
Detection of reinforcement includes number of reinforcement, spacingof reinforcement, and cover over the reinforcement etc. Ferroscan is used todetermine this reinforcement details. Ferroscan works throughelectromagnetic method. When electric current run through a coil of theapparatus, magnetic field is formed. Due to the magnetic field, electric
current run in the steel bar. Due to induced electric current in steel bar,magnetic field is formed around the bar. The field induces electric current in

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December 2007, Dhaka, Bangladesh

the secondary coil to be measured. When electric current runs through a coilof the electro-magnetic sensor, magnetic flux is measured. Electric current
runs in steel bar due to magnetic flux produced by coil of sensor.
Electromotive force of coil changes. Thickness of cover concrete ordiameter of steel bar can be estimated from magnetic flux change. Induced
magnetic field depends on the distance between sensor and reinforcement.
When bars are too close, it becomes difficult to differentiate the numbers ofbar. Principles of the method are used in Ferroscan.

3. MICROTREMOR MEASUREMENT
Soil characteristics can be assessed by microtremor measurement. Hard soil
gives high frequency and soft soil gives low frequency. A structure may
experience a vibration period at which it oscillates in the earthquake
vibration motion and will tend to response to that. Natural frequency of
structure is obtained based on the spectral ratio of horizontal component of
the building to that of ground. Wave propagation mechanism of
microtremor and its relation with ground vibration characteristics werestudied from the beginning of microtremor studies (Aki, 1957; Kanai andTanaka, 1961). Meanwhile practical application of microtremor in the fieldof engineering has advanced tremendously. One of the powerful andsimplest applications of microtremor observation is in seismic micro zoning.
Basically there are two types of microtremor observations to the number ofobservation points. These are point and array observations of microtremors(Ansary et al., 1996). From the array observation of microtremor of period
greater than 1 sec, Rayleigh-wave and Love-wave originating from natural
sources, such as sea wave, variation of air and wind pressure can berecognized. On the other hand short-period microtremor of period less than
1 sec is thought to be generated by artificial noises such as traffic vehicles,industrial plants, household appliances, etc. Some researchers (Sato et al.,
1991; Tokimatsu and Miyadera, 1992; Tokimatsu et al., 1994) have showedthat microtremors are mainly composed of fundamental mode of Rayleighwave and some (Nakamura, 1989; Wakamatsu and Yasui, 1995) haveshowed that short-period microtremor bears resemblance to shear-wave
characteristics. On the other hand, micro tremors can also be dominated byLove-wave (Tamura et al., 1993). Recently, Suzuki et al. (1995) haveapplied microtremor measurements to the estimation of earthquake groundmotions based on a hypothesis that the amplitude ratio defined by Nakamura
can be regarded identical with half of the amplification factor from bedrockto the ground surface. However, the real generation and nature of
microtremors have not yet been established.

4. PROCEDURE
For Microtremor observation, the team members fix the sensors first. They
tried to fix one sensor at the roof top of the building, one at the free fieldnear the building and other at any floor level of the building. In somebuilding the team cannot place one sensor at the rooftop, and then they place

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it at the top floor level of the building. Sometimes they have to takeobservation of two building together to save time. After taking theobservation with the help of a program the time domain velocity data isconverted to frequency domain data and find out the natural period of thebuildings. For Ferroscan observation the team identified the column andmarked them in drawing as well as in the structural part of the building.
Then they scan it carefully with the scanner and store the data. The collected
raw data were analysed with the help of the ferroscan software. Microtremor
measurement instrument and Ferroscan instrument are shown in Figure 1.

Figure 1 (a): Microtremor equipment with Battery, 3-component velocity
sensor, GEODAS-10-24S

Figure 1(b): Marking of reinforcement placement at a column of 11 story
Tower building

5. DETECTION
BUILDINGSOF

EARTHQUAKEVULNERABILITYOF

There are totally 84 buildings owned by BUET. The team studied all RC
buildings which cover academic buildings, Residential buildings, andStudent’s Dormitories of BUET campus. Academic buildings include Civil
Engineering Building, EME Building, Architecture Building, URP Building,
ARC Building, Library Building, IFCDR Building, Controller Building and
New Academic building (under construction). Residential buildings include

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December 2007, Dhaka, Bangladesh

Eleven Story Tower Building, building number 62. Student’s Dormitories
include Sher-e Bangla Hall, Titumir Hall. School Building includes
Engineering University School Building. The buildings exist outside the
BUET campus includes Headquarters of the Forest Department and Fire
Service Station (head office building at Fulbaria and a branch office at
Lalbag). Earthquake vulnerability of the surveyed buildings are assessedfrom natural frequency obtained by analysis of microtremor data
(resonance), reinforcement detection by ferroscan, concrete compressive
strength by Schmidt hammer test and visual inspection (structural
irregularities). An example of a observed building is given in details. Table
1 shows the information about the building. In Figure 2 structural elementlayout plan of 11 story tower building is shown. Figure 3 shows theMicrotremor observed time domain and converted frequency domain data.
The peak value clearly shows the fundamental period of the building. Figure
4, 5 and 6 show the designed and observed reinforcement details of thebuilding. It clearly shows the variation of location and spacing of
reinforcement from designed section. The predominant period of thebuilding is not close to that of the soil, so there is no possibility of resonance.
The building has major structural irregularities such as soft story and reentrant corner. Concrete compressive strength from Schmidt Hammer Test
is not satisfactory. Variation of clear cover from design is high. Spacing oflateral ties in column is not as per code. So, seismic vulnerability conditionof the building is high.

6. EMPIRICAL FORMULA FOR FUNDAMENTAL PERIOD OF
BUILDINGS
Most of the building codes define the magnitude of force, which should besustained by buildings at specific stress level, related to the building period
and provide the empirical formula to determine the lower boundfundamental period in order to establish the minimum load requirements.
National Research Council (1995) defines that if the number of story is N
then the fundamental period will be
T = 0.1 N
With this relation a graph is plotted in Figure 7. From analysis of
Microtremor observations, natural periods are also obtained. Microtremor
observations give lower results for frame structure type buildings than thatin National Research Council. For frame structures buildings empirical
relations is developed which is shown in Figure7.

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Table 1: Information of Eleven Story Tower Building
General Information
Compressive Strength byYear of Construction: 2002
Schmidt Hammer
Type of Structure: Frame structure
Beam: 20.0 MPa (2917 psi)
No of story: 11
Column: 20.5 MPa (3005 psi)
Floor area: 673 sqm/floor
Shear wall: not available
Foundation: Footing, pile
Lift: yes
Stair: yes
Shear wall: yes
Structural Irregularities in Plan:
Torsional irregularity: no
Re-entrant corner: yes
Diaphragm discontinuity: yes
Out of plan vertical element offset: no
Nonparallel system: no
Structural Irregularities in Height:
Storey stiffness irregularity: yesStorey mass irregularity: yesStorey geometry irregularity: no
Discontinuity of structural element: no
Discontinuity in capacity: no

5240

6860

4170

6860

5240

4630

5540

2080

Sensor 4F

1170
1170
2080

Sensor 9F

5540

4630

Sensor Roof

SensorFree Field

X

Figure 2: Structural element layout plan of Eleven Story Tower Building(linear dimensions are in millimeter)

Evaluation of the Seismic Vulnerability of Bangladeshi RC Building Using Non-Destructive Testing237

December 2007, Dhaka, Bangladesh

X direction

Y direction

UD direction

Figure 3(a) Time history of Eleven Storey Tower Building (top floor)

Figure 3(b) Fourier Spectrum of Eleven Storey Tower Building (top floor)
500

28 days cylinder strength =20.0 MPa (3000 psi)

66

16-22mm

10mm @250 c/c

500side 'A'
472
381
293
201
96

99

71

183
285
389

Design Section (linear
dimensions are in millimeter)

Concrete compressive
strength from Schmidt
Hammer Test = 20.5 MPa(3005 psi)
Observed lateral tie 253, 252,
258, 259 mm in side A and
188, 255, 251, 259 mm in sideB.

478

Observed Section (linear
dimensions are in millimeter)side 'B'

49

Figure 4: Designed and observed section of a typical column

238

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ICUS Report 27

2-16mm10mm @150c/c

500

3-22mm58

55 avg
88

50

155

65

221

250

62

28 days cylinder strength = 20.0
79
MPa (3000 psi) for designed and141
Concrete compressive strengthfrom Schmidt Hammer Test = 20.0
137
MPa (2917 psi) for observed
section.
Design Section
Observed Section
Figure 5: Designed and observed section of a typical beam

16mm @ 150 c/c
10mm @ 150 c/c

250

50
40

28 days cylinder strength = 20.0
Spacing 163, 140, 161, 160, 153, 131
MPa (3000 psi)
mm respectively
Design Section
Observed Section
Figure 6: Designed and observed section of a shear wall (Lift Core)
Table 2: Predominant period of 11 story tower building and ground
Avg.
Predominant
Predominant
Predominant
Period of building
Period ofPeriod of(Sec)ground (Sec)
Building
Floorbuilding (Sec)name/no.
level
Y
X
Y
X
Y
X
dire
Directio directio Directi directi Directi
ctio
n
n
on
on
on
n
0.50
0.50
Eleven-Story Roof
0.50
0.50
0.70 0.65
Tower
9th
0.50
0.50
th
Building
4
0.50
0.50

Evaluation of the Seismic Vulnerability of Bangladeshi RC Building Using Non-Destructive Testing239

December 2007, Dhaka, Bangladesh

1.5

Natural Period,T (sec)

BNBC 1993
Microtremor Observation, X Direction
Microtremor Observation, Y Direction
Linear Empirical Relation1

0.5
T = 0.04N + 0.133

0
0

5

10

15

Number of Story, N

Figure 7: Empirical relation between number of story and Natural Period ofsurveyed RCC Buildings

7. CONCLUDING REMARKSIn this study, the dynamic properties of low and medium-rise reinforced
concrete buildings with various heights within BUET campus were
investigated. The controlled human excitation was applied to amplify theambient vibration responses in order to improve the accuracy of theidentification of dynamic properties. There are totally 84 buildings within
BUET campus that are categorized as 15 RC building and 69 Masonrybuilding. Also, three buildings were investigated outside BUET campus.
This study covers 18 RC buildings for microtremor analysis and Ferro scan
analysis. Amidst the 18 buildings, Microtremor analyses of 17 RC building
were performed in details. Moreover, Ferroscan studies of 13 RC buildings
were performed. Empirical correlation between number of story and natural
period of RC buildings is developed.
Amidst seventeen RCC frame structure buildings natural period offour buildings are not close to that of soil, so they are out of danger ofresonance and natural period of the remaining thirteen buildings are close tothat of soil, so their seismic response can be considerably amplified. Among
surveyed RCC frame buildings seven buildings have soft story. Results
obtained from ferroscan data analysis are not satisfactory. Variation of coverand spacing of lateral ties in columns and stirrups in beam from design areabove acceptable limit. Concrete compressive strength from Schmidt
hammer test is found satisfactory for four buildings and unsatisfactory fornine buildings. Empirical correlation between number of story and natural
period of building for RCC frame buildings is
T = 0.04N+0.133

240

Where, T = Natural period of building

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

N = Number of story
Earthquake vulnerability of the surveyed buildings are assessed fromnatural frequency obtained by analysis of microtremor data (resonance),
reinforcement detection by Ferroscan, concrete compressive strength by
Schmidt hammer test and visual inspection (structural irregularities). Amidst
seventeen buildings earthquake vulnerability nine buildings is moderate andthat of five buildings is high. Five buildings for which earthquake
vulnerability is high, detail structural analysis is required to confirm thesituation.

REFERENCES
Aki, K. (1957). Space and time spectra of stationary stochastic waves, withspecial reference to microtremors, Bull. of earthquake research
institute, 35, 415-456.
Ansary, M.A., Yamazaki, F. and Katayama, T. (1996). Application of
Microtremor Measurements to the estimation of site amplification
characteristics, Bulletin of ERS, Vol 29, pp: 96-113.
Nakamura, Y. (1989). A method for dynamic characteristics estimation of
subsurface using microtremor on the ground surface, QR of RTRI, 30,
25-33.
National Research Council (1995). The Building Code: Canada.
Saha, R. (2006). Earthquake Vulnerability Assessment of BUET Buildings,
Undergraduate Thesis, Department of Civil Engg., BUET, Dhaka.
Sato, T., H. Kawase, M. Matsui, and S. Kataoka (1991). Array measurementof high frequency microtremors for underground structure estimation,proc. 4th int. conf. on seismic zonation, 11, 409-416.
Suzuki, T., Y. Adachi, and M. Tanaka(1995). Application of microtremor
measurements to the estimation of earthquake ground motions in
Kushiro city during the Kushiro-oki earthquake of 15 January 1993,
Earthq. Eng. Struct. Dyn., 24, 595-613.
Tamura, T., O. Nagai, H. Kikubo, and H. Sumita (1993). Characteristics ofwave group microtremors obtained by array measurement, J. Struct.
Consr. Eng. AIJ 449, 83-91 (in Japanese)

Evaluation of the Seismic Vulnerability of Bangladeshi RC Building Using Non-Destructive Testing241

December 2007, Dhaka, Bangladesh

242

New Technologies for Urban Safety of Mega Cities in Asia

DUCTILITY OF CONCRETE STRUCTURES
WITH LATERAL AND COMPRESSION
REINFORCEMENT
MD. SHAH AZIZ AKAND
The University of Asia Pacific, Dhaka, Bangladeshsohoj_pl@yahoo.com
IFTEKHAR ANAMThe University of Asia Pacific, Dhaka, Bangladesh
ifteanam@accesstel.net
ABSTRACTThe paper presents results of numerical and experimental works on
the effect of confining reinforcement and compression bars on the ductilityof concrete cylinders and RC beams in particular. The study demonstrates
the importance of lateral and longitudinal reinforcement on the ductility of
RC structures, which is one of the most important parameters in theirearthquake resistant design. The tests on standard concrete cylinders showthat their ultimate strains are more than doubled if confined by hoop-steels
at a spacing of 10 cm. Bending tests are performed on simply supported
beams under third-point loading with and without compression
reinforcements. The test results show that lateral reinforcements increase
the crushing strains of concrete considerably while compression
reinforcements ensure that there is no significant loss of member strengths
even after the crushing of concrete. On the other hand, the distress and lossof strength of beams without compression reinforcements spacing issignificant. The experimental load versus midspan deflection data show
satisfactory agreement with numerical results in general, although thenumerical simulations do not satisfactorily model the structural behavior at
concrete spalling and after the crushing of concrete, particularly in theabsence of compression bars.

1. INTRODUCTION
One of the primary tasks of an engineer designing an earthquake resistantbuilding is to ensure that it possesses enough strength and ductility towithstand the size and types of earthquake the structure is likely toexperience during its lifetime. Structural engineers need to understand theeffect of ductility on the building response when it is subjected toearthquake force. If properly induced in the building system, ductility will
improve the behavior of the building system primarily by reducing theforces in the structure. Therefore, it is an essential attribute of an earthquake
resistant design of structures that serves as an energy absorber in a structure
and reduces the transmitted force to one that is sustainable. At the same time,
the brittle failure of several RC frame structures during earthquakes is243

December 2007, Dhaka, Bangladesh

largely attributed to the lack of awareness or knowledge about the ductility
requirement of the members among practicing engineers.
The importance of ductility and detailing of RC sections have been
demonstrated for years in the works of several researchers, the more recent
ones including Bertero et al. (1991), Machida et al. (1999), Engelkirk (2003).
That the ductility and strength of concrete is greatly enhanced by confining
the compressive zone with closely spaced lateral steel has also been
demonstrated by various workers. In order to quantify the ductility ofconfined concrete, a number of stress-strain models for confined concrete
have been derived. The importance of enhancing the ductility capacity of
RC sections became well known after the 1971 San Fernando earthquake.
Kent and Park (1971) developed a stress-strain model of confined concrete,followed by many others, accounting for the effect of lateral confinement.
But axial load has been found to affect unfavorably the ductility offlexural members. In fact, it has been shown that ductile failure occurs onlywith axial loads considerably less than the balanced load. On the other hand,compression reinforcement can increase significantly the flexural ductilityof RC sections, as demonstrated by Blume et al. (1961).

2. CONTEXT AND OBJECTIVES
Ductility is perhaps the single most important factor in the earthquake
resistant design and detailing of RC structures. The importance of shear andcompression reinforcements in the detailing of RC structures has long beenemphasized in several building codes including the Bangladesh National
Building Code (BNBC, 1993). Despite the presence of a chapter (Chapter 8of PART 6) on Detailing of Reinforced Concrete Structures in BNBC 1993,
seismic detailing is known very little and practiced even less by the
structural designers of Bangladesh. The recently published Earthquake
Resistant Design Manual by Bangladesh Earthquake Society (Ansary &Noor, 2006) is a welcome introduction to this type of literature here. The
present work is the first of its kind at The University of Asia Pacific (UAP),
and perhaps in Bangladesh. Its importance can be assessed in this context.
The main objective of the current work is to study the effectiveness oflateral reinforcements/confinement as well as compressive reinforcement on
the ductility of RC structures. It demonstrates results of numerical andexperimental works performed at The University of Asia Pacific on theeffect of shear and compression reinforcement on the ductility of concrete
cylinders and RC beams (Akand, 2007).
The tests on standard (15 × 30 cm) concrete cylinders are performedby varying the spacing of confining reinforcement and studying the effecton their ultimate strains. Moreover, the stress-strain relationship of concreteand steel are modeled from the experimental data. Bending tests are
performed on simply supported beams of 1.8 m span with (15 × 20 cm)
sections under third-point loading with and without compression

244

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reinforcements with stirrups at 5, 10 and 20 cm spacing. The experimentalload versus midspan deflection data are compared with numerical results.

3. THEORETICAL AND NUMERICAL WORK
3.1

Material models

Among the two constituents of Reinforced Concrete, concrete is muchstronger in compression than in tension (tensile strength is of the order of
one-tenth of compressive strength). While its tensile stress-strain
relationship is almost linear, the stress-strain relationship in compression is
nonlinear. As mentioned before, several equations have been suggested tomodel this nonlinear relationship. Among them, the well known Hognestad
model (1952) [given by Equation (1a) and (1b)] has been chosen andslightly modified in this work [Equation (2)].
fc = fc′ [2(ε/ε0) − (ε/ε0)2], if ε ≤ ε0
and fc = fc′ [1 − 0.15 (ε/ε0 −1)/(εu/ε0 − 1)], if ε > ε0
fc = fc′ [2(ε/ε0) n/2 − (ε/ε0) n]

(1a)
(1b)
(2)

In this work, the maximum crushing strain (εu) and the strain at
ultimate strength of concrete (ε0) were found to coincide since the concrete
cylinders crushed at the maximum stress fc′ and equation (1b) was notneeded; i.e., the stress-stain (σ-ε) relationship was given only by a slightly
modified form of equation (1a). The parameter n is calculated from best
fitting the data with equation (2). The nonlinear formulation of RC beams
was based on the work by Anam & Shoma (2002) incorporating geometricand material nonlinearity.
3.2

Effect of lateral confinement

Lateral confinement is one of the most important features influencing
the seismic behavior of reinforced concrete. It refers to the influence thatlateral reinforcement (in the form of hoops or spirals) has on concrete
namely the favorable effect on ductility and strength. Mainly two types oflateral reinforcement are used to confine concrete; i.e., circular steel spirals
and square or rectangular steel hoops. Tests (Aoyama & Noguchi, 1979)
show that spirals are more effective than rectangular hoops regarding thefavorable effect on ductility and strength.
As all the stress-strain models of confined concrete have limitations,the model by Corley (1966) has been chosen in this work for as it involves
the least computational effort. This model recommends that a lower boundfor the maximum strain for concrete confined with rectangular links is
εcc = 0.003 + 0.02 (b/Lc) + (ρvfy/138)2(3)

where 0.003 represents the ultimate strain of unconfined concrete,(b/Lc) is the ratio of the beam width to the distance from the critical section

Ductility of Concrete Structures with Lateral and Compression Reinforcement245

December 2007, Dhaka, Bangladesh

to the point of contraflexure, ρv is the ratio of the volume of confining steel
to the volume of concrete confined and fy is the yield strength (MPa) of theconfining steel. Once the value of εcu is known, the ductility ratio can also
be calculated for singly reinforced as well as doubly reinforced sections.
3.3

Moment-Curvature relation for RC section

The M-φ relationship of arbitrary RC sections can be derived
numerically by the application of simple principles of Strength of Materials.
The arbitrary area can be divided into a number of segments. For a given
curvature, the position of the neutral axis is determined by trial and error;i.e., assuming a neutral axis, calculating the strain and stress at various
points of the section and equating the compressive and tensile forces. Oncethe neutral axis is chosen, the moment M is easily calculated by summing
the moments of all the forces on the section. Using the moment-curvature
relationship thus specified, the load vs. deflection relationship for the thirdpoint loading of a simply supported beam is obtained numerically.

4. EXPERIMENTAL SETUP
A significant portion of this research concentrated on the experimental workin the Structural Mechanics and Strength of Materials Lab of UAP. It
primarily involved the laboratory testing of a simply supported beam underthird-point loading, varying the stirrup spacing and amount of compression
reinforcement. The axial stress-strain relationships of concrete cylinders andsteel reinforcements were evaluated prior to the tests. Some backgroundfieldwork was also necessary as preparation for this work, primarily
involving concrete mixing, rod bending, stirrup binding as well as casting
and curing of concrete cylinders and beams. Figure 1(a) and 1(b) showbinding of longitudinal tensile and compressive reinforcements as well aslateral (stirrup) reinforcements.
Two sets of concrete cylinders were cast in the laboratory for thesubsequent beam casting and tests. Set 1 consisted of unconfined concrete
cylinders (15 cm diameter and 30 cm height) while Set 2 included
unconfined as well as confined cylinders, using 4 hoops spaced uniformly
over the cylinder height. Every cylinder was compacted by vibrator andcured for 60 days in Set 1 and 28 days for Set 2.
4.1

Casting of concrete beams

Set 1: There were three types of beams, each being a rectangular beam
length of 1.8 m and section (15 cm × 20 cm) but with stirrup spacings of 5,
10 and 20 cm. Two layers of rod (12 mm bars) were placed in the beam
members; i.e., 2 compression rods at top and 3 tensile rods at bottom.
For Set 2: Similar to Set 1, the only difference is that it used 3 tensile
rods at bottom and 2 timber bars in compression only for binding the246

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stirrups. As the strength and modulus of timber is of the same order as
concrete’s, it was used here instead of steel to better simulate the behaviorof singly reinforced beams. Like the cylinders, the Set 1 beams are also
cured for 60 days and Set 2 beams for 28 days.

Figure 1: Rod binding with (a) Different spacing of lateral reinforcement,(b) Timber rod as compression reinforcement
4.2

Setting up beam members in the testing instrument

The 1.8 m span beam is supported by a steel I-section of similar length.
However, the effective span of the beam is made 1.5 m corresponding to the
distance between supports. Load is applied at the mid section and divided
into two equal parts by a 50 cm simply supported bridge. Figure 2(a) and2(b) show pictures of the experimental set up.

Figure 2: Experimental set up shows (a) Beam under Third-Point Loading,(b) Arrangement to measure beam deflection

Ductility of Concrete Structures with Lateral and Compression Reinforcement247

December 2007, Dhaka, Bangladesh

5. RESULTS FROM NUMERICAL ANALYSIS AND EXPERIMENT
5.1

Effect of lateral confinement

As mentioned, the concrete cylinders of Set 2 were tested without
confinement as well as after confining them with 10 mm bars (4 hoops),
calculating εc0 by modifying equation (3) slightly to incorporate the material
properties and structural member used in this work. The ultimate strength of
confined concrete is also calculated here analytically [Mander et. al. (1988)].
Table 1 shows that the analytical results compare reasonably well with theexperimental values of concrete strength and ultimate strain.
Table 1: Effect of confinement reinforcement.
S(cm)
0 (Unconfined) *410No. of Hoops

5.2

ρv
(%)
0
2.03

εcc (10-3)
Calc Measured
3.36
6.23 7.37

fcc′ (Mpa)
Calc Measured
20.41
23.92 23.37

Material and sectional properties for numerical modeling

Since the material properties for concrete (i.e., its strength andductility) depend on the confining reinforcements, they need to be specified
for the numerical analyses. Table 2 shows the variation of ultimate crushingstrain and strength of concrete with confinement spaced at 5, 10 and 20 cm.
It may be mentioned here that the unconfined strength and strain were used
for the portion outside the stirrup reinforcement while the confined values
were chosen for the concrete within the closed stirrups.
Table 2: Material properties for beams.
Set
1
2

5.3

StirrupSpacing (cm)
5
10
20
5
10
20

εcc (10-3)
Unconfined Confined
11.10
2.79
6.12
4.87
11.40
3.36
6.62
5.42

fc′ (MPa)
Unconfined Confined
44.6
34.3
38.4
36.9
25.3
20.4
22.4
21.7

Experimental and numerical results for beams

As mentioned, Set 1 and Set 2 beams were tested for stirrup spacing of
5, 10 and 20 cm. Only selective load vs. deflection graphs are shown in thispaper (for two extreme cases); i.e., results for three beams of Set 1 (withcompression rods) with stirrup spacing of 5 cm are shown in Figure 3, while
Figure 4 shows the corresponding graphs for Set 2 beams (virtually without
any compression rod, i.e., with timber bars in the compression zone) withstirrup spacing of 20 cm. In both cases, Figure (a) shows the experimental
graphs of the three beams and Figure (b) shows the numerical results.

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L o ad (k N)

Beam1

Beam2

Beam3

120

120

100

100

80

80

60

60

40

40

20

20

0

0

0

20

40

60

80

100

0

20

40

60

80

100

Deflection (mm)Deflection (mm)L o ad (k N)

Figure 3: (a) Experimental and (b) Numerical Deflection vs. Load graphsof Set 1 beams (Stirrup @ 5 cm)
100

100

80

80

60

60

40

40

20

20

0
0

20

40

60

80

100

0
0

Deflection (mm)

20

40

60

80

100

Deflection (mm)Figure 4: (a) Experimental and (b) Numerical Deflection vs. Load graphsof Set 2 beams (Stirrup @ 20 cm)
Since the results for the individual beams are somewhat different fromeach other, they are difficult to compare with the corresponding numerical
data. More conveniently, Table 3 and 4 compare average values of theimportant parameters of the load-deflection graphs for Set 1 and Set 2
respectively (i.e., loads and deflections corresponding to elastic limit,
spalling and crushing of concrete).
Table 3 shows reasonable agreement between theoretical andexperimental loads and the corresponding deflections. This is somewhat true
for Table 4 also except in case of spalling, where the numerical andexperimental results differ significantly. This is perhaps due to the fact that
equation (3) does not incorporate the spalling of concrete, a limitationcompensated by the effect of compression reinforcement for Set 1.
The tables also demonstrate the positive effects of lateralreinforcement on the ductility of RC beam sections, particularly in the

Ductility of Concrete Structures with Lateral and Compression Reinforcement249

December 2007, Dhaka, Bangladesh

absence of compression rods. For example, in Set 1 (Table 3) the averagevalue of ultimate deflection corresponding to stirrup spacing of 5 cm is 68
mm (90 mm using numerical analysis) but it decreases to 52 mm (74 mm
from numerical analysis) and 52 mm (59 mm from numerical analysis) for
stirrup spacings of 10 and 20 cm respectively. The effect is less serious forthe ultimate loads (decreasing from 105 kN to 99 kN and 92 kN), but much
more significant in the absence of compression rods (Table 4).
Table 3: Experimental and numerical results for Set 1 beams.
StirrupSpacing
5 cm
10 cm
20 cm

Sample
Avg
Num
Avg
Num
Avg
Num

Elastic Limit
Load Def
(kN)
(mm)
87
6.0
83
6.3
83
5.8
83
6.8
82
6.1
83
7.8

Spalling
Load Def(kN) (mm)
95
20
78
14
93
23
82
22
90
20
84
26

Crushing
Load Def(kN) (mm)
105
68
99
90
99
52
95
74
92
52
92
59

Table 4: Experimental and numerical results for Set 2 beams.
StirrupSpacing
5 cm
10 cm
20 cm

Sample
Avg
Num
Avg
Num
Avg
Num

Elastic Limit
Load Def
(kN)
(mm)
80
5.4
71
6.8
77
5.4
73
6.3
70
5.3
74
6.3

Spalling
Load Def(kN) (mm)
75
25
36
7.3
79
20
60
9.3
71
17
61
9.3

Crushing
Load Def(kN) (mm)
91
61
74
46
77
37
69
25
71
17
67
20

Here the ultimate beam deflection for stirrup spacing of 5 cm
decreases from 61 mm (46 mm from using numerical analysis) to 37 mm(25 mm from numerical analysis) for stirrup spacing of 10 cm and only 17
mm (20 mm from numerical analysis) for stirrup spacing of 20 cm. The
corresponding decrease in ultimate loads (experimental) from 91 kN to 77
kN and 71 kN is also more significant compared to Set 1. However, Figure
4 shows that the numerical model does not simulate properly the beam
behavior after crushing of concrete.

6. OBSERVATION OF FAILURE CHARACTERISTICS
Figure 5 shows the nature of compression failure of unconfined andconfined cylinders along with the confinement reinforcements. The presenceof confining reinforcements checks the overall rupture of the cylinders; i.e.,
the failure surfaces do not propagate from top to bottom of the cylinder. The
condition of the longitudinal and shear reinforcements after failure of thebeams are shown in Figure 6. Although the compressive steel

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reinforcements are in order for Set 1 [Figure 6(a)], this is not the case for thetimber reinforcements of Set 2 [Figure 6(b)]; i.e., showing the ones withstirrups spaced at 20 cm that failed due to compression and almost the entire
concrete volume has crushed and detached at the failure sections.

Figure 5: Crushed cylinder and failure surfaces for (a) Set 1, (b) Set 2

Figure 6: Reinforcements after failure of (a) Set 1 beam, (b) Set 2 beam

7. CONCLUSIONSThis work was particularly aimed at studying the effect of compressive andshear reinforcements in improving the ductility of RC sections, although
their effect on concrete strength was also studied. The ductility (and thecompressive strength to some extent) of concrete obtained from cylinder
tests were indeed found to increase significantly due to confinement bylateral hoops. The ultimate stress and strain predicted from literature
matched reasonably well with the experimental values. Also, there wassignificant increase in the ductility (and some increase in strength) of thebeams with closely spaced stirrups (particularly beams without compressive
reinforcements), compared to beams with sparse stirrups.

Ductility of Concrete Structures with Lateral and Compression Reinforcement251

December 2007, Dhaka, Bangladesh

The agreement between the numerical and experimental results wasvery good at the elastic limit, unsatisfactory (sometimes poor) at concrete
spalling and reasonable at the ultimate limit. The numerical analysis could
not model properly the beam behavior after concrete crushing.
Experimental and numerical results from the beam tests showedmarked difference between the behavior of beams with (Set 1) and withoutcompression reinforcements (Set 2). Even at failure, though the compressive
steel reinforcements for Set 1 were in order, the compressive timber
reinforcements of Set 2 (particularly ones with stirrups spaced at 20 cm)
failed and almost the entire concrete volume crushed at the failure section.

REFERENCES
Anam, I., and Shoma, Z. N., 2002. Nonlinear properties of Reinforced
Concrete structures. 2nd Canadian Conference on Nonlinear Solid
Mechanics, Vancouver, Canada, Vol 2, 657-666.
Akand, M. S. A., 2007. Effect of shear and compression reinforcement on
the ductility of RC members. B. Sc. Engg. Thesis, Department. of CE,
UAP.
Aoyama, H., and Noguchi, H., 1979. Mechanical properties of concrete
under load cycles idealizing seismic actions. Bulletin D’information
CEB 131, 29-63.
Bangladesh National Building Code, 1993. BNBC-93, Dhaka, Bangladesh.
Ansary, M. A., and Noor, M. A. (editors), 2006. Earthquake resistantdesign manual, Academic Press & Publishers Library, Bangladesh.
Bertero, V. V., Anderson, J. C., Krawinkler, H., Miranda, E., 1991. Design
guidelines for ductility and drift limits. UCB/EERC-91/15, Earthquake
Engineering Research Center, UC Berkeley, USA.
Blume, J.A., Newmark, N.M., and Corning, L.H., 1961. Design of multistorey Reinforced Concrete buildings for earthquake motions.
Portland Cement Association, Skokie, Illinois, USA.
Corley, W.G., 1966. Rotational capacity of Reinforced Concrete beams.
ASCE Journal of Structural Engineering 92, 121-146.
Engelkirk, R.E., 2003. Seismic design of Reinforced Concrete and Precast
Concrete buildings. John Wiley & Sons, NY, USA.
Hognestad, E., 1952. Fundamental concepts in ultimate load of Reinforced
Concrete members. ACI Structural Journal 49, 48-53.
Kent, C. C., and Park, R., 1971. Flexural members with confined concrete.
ASCE Journal of Structural Engineering 97, 1969-1990.
Machida, A., Moehle, J., Pinto, P., Park, P., and Matsumoto, N., 1999.
Ductility consideration. Proc. of Comparative Performance of Seismic
Design Codes for Conc. Str. Engg. Studies, Vol 1, Elsevier Sc., USA.
Mander, J. B., Priestley, M. J. N., and Park, R., 1988. Theoretical stressstrain model for confined concrete. ASCE Journal of StructuralEngineering 114, 1804-1826.

252

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RESIDUAL SEISMIC CAPACITY
ESTIMATION OF RC FRAMES WITH
UNREINFORCED CONCRETE BLOCK INFILLHO CHOIJSPS Postdoctoral Fellow, The University of Tokyo
choiho@iis.u-tokyo.ac.jp
YOSHIAKI NAKANOInstitute of Industrial Science, The University of Tokyo, Japaniisnak@iis.u-tokyo.ac.jp
ABSTRACTThe objective of this study is to develop a post-earthquake seismic
evaluation method for RC frames with unreinforced concrete block infill.
For this purpose, full-scale, one-bay, single-story specimens are tested
under cyclic loadings. In this paper, the residual seismic reduction factors
are discussed analytically and experimentally to estimate the residual
seismic capacity based on the observed damage class, and the damage
classes of Korean typical school building, which should be properly
functional as refugee centers as well as structurally safe after an earthquake,are investigated analytically under Korean design acceleration level.

1. INTRODUCTION
The objective of this study is to develop a post-earthquake seismic
evaluation method for reinforced concrete (referred to as RC) frames withunreinforced concrete block (referred to as CB) infill. For this purpose, fullscale, one-bay, single-story specimens having different axial loads incolumns and different opening configurations of infill are tested undercyclic loadings. During the tests, residual crack widths, which can also befound in damaged buildings, are carefully measured to estimate the residual
seismic capacity from the observed damage.
In this paper, the residual seismic capacity of RC frames with CB
infill is discussed analytically and experimentally, and the reduction factors
are proposed to estimate the residual seismic capacity based on the observed
damage class. Finally, the damage classes of Korean typical schoolbuildings, which should be properly functional as refugee centers as well as
structurally safe after an earthquake, are investigated analytically under
Korean design acceleration level.

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2. OUTLINE OF EXPERIMENT
Figure 1 shows a standard design of Korean school buildings in the 1980s(The Ministry of Construction and Transportation, 2002). In this paper, 2
specimens representing first and fourth story of 4 story RC school buildings
are investigated. They are an infilled wall type 1 (IW1) assuming the firststory and an infilled wall type 2 (IW2) assuming the fourth story. The
design details of specimen IW1 are shown in Figure 2. For loading history,
peak drift angles of 0.1, 0.2, 0.4, 0.67, 1.0, and 2.0% are planned. A
constant axial load of 1,440kN (720kN for each column) is applied to
specimen IW1 while 360kN (180kN) to specimen IW2.

7,500

10,0002,500Specimen IW1 has vertical and horizontal cracks in mortar between
CB units and flexural cracks in RC columns at +0.1%. Shear cracks are thenobserved in both columns at +0.4%. Since the shear cracks rapidly open at –1.5% in the column bottom of compression side, the test is terminated.
Specimen IW2 has a crack pattern in both columns and wall, which is almost
the same as that of specimen IW1. Although the strength deterioration isobserved at +2.0%, a rapid increase in crack width is not found. Since theshear cracks rapidly open at +3.33% in the column bottom of compression
side, the test is terminated. The response of the specimens including crack
patterns and their mechanism is discussed by Nakano and Choi (2005).

Figure 1: Standard design of Korean school buildings in the 1980s[Column]*B D : 400 450mm*Main reinforcement: 12-D22 (IW2:8-D19)*Hoop : D10@300[Concrete block]*390 190 190mm*Effective sectional area
: 46,700mm2(excluding the hollow)
400

450

3,600

450

400

5,300

[unit:mm]

Figure 2: Details of specimen IW1

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3. BASIC CONCEPTEVALUATIONOFRESIDUALSEISMICCAPACITY

Figure 3 shows the basic concept employed in this study to evaluate theresidual seismic capacity from residual crack widths observed in earthquakedamaged buildings. The seismic capacity is defined as the hysteretic energythat a structure can absorb during an earthquake, which is consistent with thebasic concept found in the Japanese Standard for Seismic Evaluation of
Existing RC Buildings (JBDPA, 2001 and 2005), since the procedure proposed
herein to evaluate the residual seismic capacity is designed to be analogous tothat of the Standard for existing (i.e., pre-earthquake damaged) buildings.
When the load-deformation relationship of a structure or members isinvestigated through loading tests prior to an earthquake and the response of
the structure such as the peak deformation δp and/or the residual
deformation δ0 are given after an event, the residual seismic capacity
Er (= ET - Ed) can be calculated by the discrepancy between initial seismic
capacity ET prior to earthquake damage and dissipated seismic capacity Ed
based on the load-deformation curve as shown in Figure 3(a).
Since the peak and residual deformations of buildings are, however,usually unknown after an earthquake unless they are instrumented, otherinformation that can be surely obtained in the damaged buildings andquantitative data that can serve as a good estimator of the peak and/or
residual deformation are therefore necessary to practically evaluate theresidual seismic capacity. In this study, the residual crack width W0 that canbe quantitatively measured on damaged buildings is focused to estimate theresidual deformation δ0 as shown in Figure 3(b), and their W0-δ0(a) Laboratory tests
Peak deform. ( p)ET = Ed + ErEdErResidual deform. ( 0)Deform.

(b) Field surveys
Crack width !
(W0)

Residual seismic capacity- Initial (Pre-EQ) seismic capacity (ET)- Dissipated seismic capacity (Ed)- Residual seismic capacity (Er = ET - Ed)
Residual deformation 0 vs.
Residual seismic capacity Er( 0-Er relation)(c) Residual crack width W0 vs.
Residual seismic capacity Er(W0-Er relation)
Residual crack width W0 vs.
Residual deformation 0 (W0- 0 relation)(e.g., 0 = f (W0))

Figure 3: Basic concept of residual seismic capacity evaluation
Residual Seismic Capacity Estimation of RC Frames with Unreinforced Concrete Block Infill

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December 2007, Dhaka, Bangladesh

relationships are experimentally and analytically studied. Once the W0-δ0relation and the δ0-Er relation of typical buildings where damage is expectedduring an earthquake are clarified and the W0-Er relation is then established,
the residual seismic capacity Er of a damaged building can be evaluatedthrough the crack width W0 that can be measured during a damage survey.
In the following sections, the δ0-Er relation (see Figure 3(a)) is only
investigated for RC frames with CB infill.

4. RELATIONSHIP OF RESIDUALRESIDUAL SEISMIC CAPACITY
4.1

DEFORMATION

AND

Estimation of Residual Seismic Capacity by Residual Deformation

In this section, the relationship of the residual deformation (δ0) and theresidual seismic capacity (Er) is investigated. For this purpose, the loaddeformation curves obtained during the loading tests are approximated witha simplified model, and the seismic capacity reduction factor η is employedbased on the model.
The load-deformation curve is first characterized by the following threebasic points on the curve, the yield drift angle Ry, the maximum response drift
angle Rp, and the ultimate drift angle Ru, where the drift angle is defined as theratio of deformation to the column height (h=2,400mm) of specimens. In thisstudy, Ry, Rp, and Ru are defined as shown below.
Ry : Drift angle when column longitudinal reinforcement yields
Rp : Drift angle when a structure reaches its maximum response deformation
Ru : Drift angle when the lateral load carrying capacity decreases to 80% of
the peak load

Figure 4 shows the characteristic points Ry and Ru of specimens IW1 andIW2 together with damage class determined considering its definition for RC
members in the Guidelines for Post-Earthquake Damage Evaluation andRehabilitation of RC Buildings in Japan (2001) shown in Table 1 and Figure 5.
ⅠⅡ Ⅲ

Ⅳ Ⅴ Damage ClassⅠⅡⅢ

Ⅳ Ⅴ Damage Class

1200
IW1

Load (kN)

P

IW2

900
P

600

Ed

Er

300

Ed

0
0.0
R0

0.5

1.0 1.5 2.0 2.5
Drift angle, R (%)

Ry Rp

Ru

3.0

0.0
R0

Er

0.5

1.0 1.5 2.0 2.5
Drift angle, R (%)

Ry Rp

3.0

3.5

Ru

Figure 4: Load-drift angle relationship of specimens IW1 and IW2

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Table 1: Damage Class Definition of RC Columns and Walls (JBDPA, 2001)
Damage
class
I
II
III
IV

V

Description of damage- Visible narrow cracks on concrete surface(Crack width is less than 0.2 mm)- Visible clear cracks on concrete surface(Crack width is about 0.2 -1.0 mm)- Local crush of concrete cover- Remarkable wide cracks (Crack width is about 1.0 - 2.0 mm)- Remarkable crush of concrete with exposed reinforcing bars
- Spalling off of concrete cover (Crack width is more than 2.0 mm)- Buckling of reinforcing bars
- Cracks in core concrete- Visible vertical and/or lateral deformation in columns and/or walls- Visible settlement and/or leaning of the building
Lateral load
Vertical load
Load carrying capacity

Damage class

I

Remained

Deteriorated Lost

Remained

Lost

II

III

IV

V

Compression failureof conc. starts
Yielding oftensile rebars
Cracking

Buckling of rebars /falling of covering conc.
Deflection

Figure 5: Schematic illustrations of damage class vs. load carrying capacity(Ductile Member, JBDPA, 2001)
The ultimate ductility factor μ of each specimen defined by Ru/Ry isapproximately 2.0 and 3.0, respectively. When the structure’s response has thepeak drift angle Rp and the residual deformation angle R0, the dissipatedhysteretic energy Ed normalized with respect to the column height can becalculated from the area enclosed by the curve O-P-R0. The residual energy Er,
therefore, can be calculated from the remaining area shown hatched in Figure 4.
Assuming that the hysteretic energy defined above corresponds to the seismic
capacity, Er represents the residual seismic capacity.
To facilitate to apply this procedure to hysteretic loops with different
strength and ductility, a seismic capacity reduction factor η defined by theratio of the residual capacity Er to the initial capacity ET (=Ed+Er) is thenemployed in this study. To find the R0-η relationship of a structure in a moregeneral manner, the load-deformation curve is represented with a simplified
hysteretic model with assumptions (1) through (3) described below. Figure 6
shows the simplified hysteretic model.

Residual Seismic Capacity Estimation of RC Frames with Unreinforced Concrete Block Infill257

December 2007, Dhaka, Bangladesh(1) The Takeda model is employed for the basic hysteretic rule assuming(a) no hardening in post-yielding stiffness and (b) stiffness degradation
factor α of 0.7 derived from the test results during unloading.
(2) The load Qcr and drift angle Rcr at cracking point are assumed Qy/3 andRy/15, respectively, where Qy and Ry are the characteristic points atyielding.
(3) The descending branch beyond the ultimate drift angle Ru linearlydecreases to (μ+1)Ry onto X-axis where the ductility factor μ is defined by
Ru/Ry, which is analogous with the concept found in Maeda et al. (2000).
Figure 7 shows the relationship between the seismic capacity
reduction factor η and the residual drift angle R0 for different ultimate
ductilities together with the test results. As described earlier, the ductility
factors of IW1 and IW2 are approximately 2.0 and 3.0, respectively, andFigure 7 shows good agreement of numerical simulations with test results.

Figure 6: Simplified hysteretic modelη (= Er / ET)

1.0

Analysis
Experiment

0.8
0.6

IW2

0.4
0.2
0.0
0.0

IW1
μ=1

μ=2

μ=3

0.4
0.8
1.2
1.6
Residual drift angle, R0 (%)

μ=6
μ=5
μ=4

2.0

Figure 7: Relationship of R0 and η
4.2 Estimation of Residual Seismic Capacity Corresponding to Damage
Class
It should be noted that damage evaluation of buildings in the field isoften made based on damage classification such as shown in Table 1 rather
than direct and detailed description of measured digital data.
To facilitate to apply the relation found in Figure 7 in practice, thereduction factor η is plotted in Figure 8 with respect to the damage class I
through V considering the relationship of peak drift angle and damage class258

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Seismic capacity reduction factor, η (= Er / ET )ICUS Report 27

I

II

III

IV

V Damage Class

1.0
Analysis
Experiment

0.9
0.8
0.7
0.6
0.5
0.4

IW1

0.3
0.2
0.1
0.0
0.0

μ=2

0.2

0.4
0.6
0.8
1.0
Residual drift angle, R0 (%)

1.2

1.4

Figure 8: Seismic capacity reduction factor η vs. damage class
Table 2: Seismic capacity reduction factor η corresponding to damage class
Damage
Class
I
II
III
IV
V

Proposed in this study
for RC frameswith CB infill
0.90
0.60
0.30
0.00
0.00

Specified in the Guidelines (JBDPA, 2001)
Brittle RC column
Ductile RC column/ RC wall
0.95
0.95
0.60
0.75
0.30
0.50
0.00
0.10
0.00
0.00

shown in Figure 4, where data of specimen IW1 is used since serious
damage is often found in the first story.
The results are summarized in Table 2 comparing factors specified in the
Guidelines (JBDPA, 2001), where the proposed factors are determined as theaverage of experimental and estimated values at the boundary of two adjacentdamage classes in Figure 8. Note that the factors for damage classes IV and V
are assumed 0 to conservatively evaluate the results. As shown in the table, thevalues of η determined in this study are almost the same as those for brittle RC
column and wall in the Japanese Guidelines, since specimen IW1 is not ductile
enough to maintain the peak load far beyond yielding.
The residual seismic capacity Er of RC frames with CB infill can be
estimated from the following procedure.
(1) Calculate the seismic capacity ET of an original (i.e., pre-earthquake
damaged) sub-assemblage or frame with CB infill.
(2) Classify its damage into one of five categories based on a damage survey.
(3) Determine the seismic capacity reduction factor η based on the damage
class made in (2) above. (see Table 2)(4) Calculate the residual seismic capacity Er as η ET.

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December 2007, Dhaka, Bangladesh

5. DAMAGE CLASS OF KOREAN TYPICAL SCHOOL BUILDING
5.1

Ground Motion Data

In this section, the damage classes of Korean typical school buildings,
which should be properly functional as refugee centers as well as
structurally safe after an earthquake, are investigated analytically against
future earthquakes. Since the earthquakes of maximum acceleration level
determined Korean seismic design provisions have been not occurred, six
artificial ground motions are used in this study. A target elastic spectrumwith 5% of critical damping SA (T, 0.05) is then determined by Equation (1).
⎧0.18 + 2.64T⎪
S A (T ,0.05) = ⎨0.44
cm / sec 2⎪0.23 T⎩T < 0.1sec
0.1sec ≤ T < 0.52 sec(1)

T ≥ 0.52 sec

where T is the natural period of the SDOF model. The following 6 records
are used to determine phase angles of ground motions: the NS component of
El Centro 1940 record (referred to as ELC), NS component of Kobe 1995
record (KOB), EW component of Hachinohe 1968 record (HAC), NS
component of Tohoku University 1978 record (TOH), NS component of
Uljin 2004 record (ULJ) which has the highest maximum acceleration levelof earthquake data measured Korean Meteorological office, and random
excitation (RAN). Table 3 shows the maximum acceleration of artificial
ground motion and Figure 9 shows the elastic acceleration response spectraof artificial ground motions with 5% of critical damping.
Table 3: Input ground motion

5.2

400
2

Max. GroundAcceleration(cm/sec2)
341.7-821.0
183.0
258.0
72.5
-

SA (cm/sec )GroundMotionRecord ID
ELC
KOB
HAC
TOH
ULJ
RAN

500
Artificial Wave
Target spectrum

300
200
100
0
0.0

0.5
1.0
1.5
2.0
2.5
Predominent period, T (sec)

3.0

Figure 9: Elastic acceleration spectra

Damage Class Estimation of Korean Typical School Building

In this section, the damage classes of Korean typical school building
based on the standard design specification in the 1980s are estimated using
six artificial ground motions mentioned previous section. In this paper, 4
story frames as shown in Figure 1, where transverse direction including CB
walls used as partition walls is selected since high seismic capacity is
expected, are analyzed.

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To simulate the inelastic behaviors of model structure and to estimate
the damage classes, the Takeda hysteretic model is employed withassumptions (1) through (3) described below.
(1) The model is assumed as no hardening in post-yielding stiffness andstiffness degradation factor α of 0.7.
(2) The yield load Qy is calculated as the sum of shear strengths of threecolumns and one CB infill (the average shear stresses of CB infills for
specimens IW1 assuming the first story and IW2 assuming the fourthstory are approximately 0.4N/mm2 and 0.3N/mm2, respectively, from test
results, and those for the second and the third stories are roughly
assumed 0.35N/mm2). The yield drift angle Ry is assumed 0.67% fromtest results. The load Qcr and drift angle Rcr at cracking point are
assumed Qy/3 and Ry/15, respectively.
(3) The ultimate ductility factors μ of specimens IW1 and IW2 areapproximately 2.0 and 3.0, respectively, and those for the second and thethird stories are roughly assumed 2.5.

1200

I

Damage class
II III
IV

900

KOB

600

Load (kN)

ELC

Load (kN)

Figure 10 shows the inelastic behaviors of first story of model
structure, where is often found serious damage, for six artificial ground
1200

I

Damage classII
III IV

900
600
300

300

0
0
-1.4-1.2-1.0-0.8-0.6-0.4-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 -1.4-1.2-1.0-0.8-0.6-0.4-0.20.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
-300
-300
Drift angle, R (%)
Drift angle, R (%)
-600
-600

Load (kN)

HAC

IV

III
II -1200
I
Damage class

1200

I

Damage classII
III IV

900

TOH

600
300

-900
III II -1200
I
Damage class
Load (kN)

-900
IV

1200

I

Damage classII
III IV

900
600
300

0
0
-1.4-1.2-1.0-0.8-0.6-0.4-0.20.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 -1.4-1.2-1.0-0.8-0.6-0.4-0.20.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
-300
-300
Drift angle, R (%)
Drift angle, R (%)
-600
-600
IV

I

Damage classII
III IV

RAN

600
300

-900
III
II -1200
I
Damage class
1200

Load (kN)

Load (kN)-900
II -1200I
IV III
Damage class
1200
ULJ
900

I

Damage classII
III IV

900
600
300

0
0
-1.4-1.2-1.0-0.8-0.6-0.4-0.20.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 -1.4-1.2-1.0-0.8-0.6-0.4-0.20.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
-300
-300
Drift angle, R (%)
Drift angle, R (%)
-600
-600
-900
IV III II -1200
I
Damage class

IV

-900
III II -1200
I
Damage class

Figure 10: Inelastic behaviors and damage classes of first story
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December 2007, Dhaka, Bangladesh

motions together with the damage classes. As shown in the figure, thebehaviors and damage classes are different due to phase angles of eachground motion. However, all of results exceed the maximum strength, andthe results of KOB, HAC and RAN particularly exceed the ultimate drift
angle of 1.35% and reach in the state of damage class V (i.e., collapse). This
result means that Korean typical school buildings cannot escape more thanmoderate damage and do not play a role as refugee centers after theearthquake of Korean design acceleration level.

6. CONCLUSIONS

RC frames with concrete block (CB) infill representing typical schoolbuildings in Korea are tested under cyclic loading to estimate the residual
seismic capacity from residual crack widths measured on CB walls. The
results can be summarized as follows.
(1) The load-deformation curves obtained during the tests are thenapproximated with a simplified hysteretic model, and the relationship of
the residual drift angle R0 and the residual seismic capacity reduction
factor η is established based on the model. The results show good
agreement with test results, which imply that the procedure proposed
herein can be applied to estimate the residual seismic capacity of RC
frames with CB infill having different strength and ductility.
(2) The values of η proposed in this study for RC frames with CB infill
corresponding to each damage class are found almost the same as those forbrittle RC column and wall specified in the Japanese Guidelines for PostEarthquake Damage Evaluation, since the proposed values are based ondata of specimen IW1, which is not ductile enough to maintain the peakload far beyond yielding.
(3) The damage classes of first story of model structure, where is often
found serious damage, for six artificial ground motions exceed the
maximum strength, and the results of KOB, HAC and RAN particularly
exceed the ultimate drift angle of 1.35% and reach in the state ofdamage class V. This result means that Korean typical school buildings
cannot escape more than moderate damage and do not play a role as
refugee centers after the earthquake of Korean design acceleration level.

REFERENCES

The Ministry of Construction and Transportation, 2002. A Study on the
Seismic Evaluation and Retrofit of Low-Rise RC Buildings in Korea. pp. 113155 (in Korean).
Nakano, Y. and Choi, H., 2005. Experimental Study on Seismic
Behavior and Crack Pattern of Concrete Block Infilled RC Frames. New
Technologies for Urban Safety of Mega Cities in Asia (USMCA),
ICUS/INCEDE Report 2, Singapore.
JBDPA (The Japan Building Disaster Prevention Association), 1977,
1990, and 2001 (in Japanese), and 2005 (in English). Standard for Seismic262

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ICUS Report 27

Evaluation of Existing Reinforced Concrete Buildings.
JBDPA (The Japan Building Disaster Prevention Association), 2001.
Guidelines for Post-Earthquake Damage Evaluation and Rehabilitation (inJapanese).
Maeda, M., Bunno, M. and Nagata, M., 2000. A Study on the Damage
Class Estimation of RC Buildings Based on Residual Seismic Capacity ofMembers. Proceedings of the Japan Concrete Institute, Vol. 22, No. 3, pp.
1447-1452 (in Japanese).

Residual Seismic Capacity Estimation of RC Frames with Unreinforced Concrete Block Infill263

December 2007, Dhaka, Bangladesh

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THE EFFECT OF INFILLS ON THE DYNAMIC
BEHAVIOR OF RC FRAMESSAMY MUHAMMAD REZA1, RAQUIB AHSAN2and MEHEDI AHMED ANSARY3
Department of Civil Engineering, BUET, Bangladesh
samyreza@gmail.com
ABSTRACT
Response of a structure to earthquakes significantly depends on its
infill condition. For general design purposes, usually structural analysis isperformed according to equivalent linear static method. This is not safe forstructure with soft story. Structures with soft story are associated withgreater deflection than normal structures. A structure does not behave
linearly when subjected to large deformation. Nonlinear analysis isassociated with increase of deformation and thus greater vulnerability. In
this study Frames with and without infills have been analyzed considering
nonlinearity and damping effects. Responses of structures, both linear andnon-linear with different infill conditions, to harmonic ground motion havebeen examined. From this study it has been found that frames with morethan 10 stories are more vulnerable due to soft-storey effect than bareframes. Vulnerability of a structure depends very much on the groundmotion frequency.

1. INTRODUCTION
Frame structures are frequently used in multistoried buildings, mainly due toease of construction and rapid progress of work. Column and girder framingof reinforced concrete, or some times steel, is infilled by panel of brickwork,
block work, cast in place or pre-cast concrete. When an in-filled frame issubjected to lateral loading, the infills behave effectively as struts along its
compression diagonals to brace the framed. Therefore, the infills serving as
external walls or internal partitions, contribute some effect on stiffness ofthe framing system. This contribution totally depends on the properties of
infilled materials, openings etc.
Without contribution of infill stiffness is greatly reduced. So, a bareframe is much less stiff than frame with infill. In case of soft story a sudden
reduction of stiffness takes place. Response of these frames to earthquake
will be different.
For large displacement, structures do not act linearly. Based on elastic
behavior, structures subjected to a major earthquake would be required toundergo large displacements. However, North American practice requiresthat structures be designed for only a fraction of the forces associated withthose displacements. The relatively low design forces are justified by theobservations that buildings designed for low forces have behaved265

December 2007, Dhaka, Bangladesh

satisfactorily and that structures dissipate significant energy as the materials
yield and behave inelastically. This nonlinear behavior, however, usuallytranslates into increased displacements, which may result in major
nonstructural damage and require significant ductility. Displacements may
also be of such magnitude that the strength of the structure is affected bystability considerations.
The objective of the study is to develop a program, by which responseof multi-degrees of freedom system to ground motion can be determined. To
determine natural frequency of building frames of different height anddifferent infill conditions, by the proposed program. To compare responseof building frames with different infill conditions to ground motion by linear
and nonlinear analyses, nonlinear analysis without damping and nonlinear
analysis with damping.
The 6-story, 10-story and 15-story 3-bay building frames are modeled
for frame with full infill, frame without any infill and frame with soft story.
Columns provide lateral stiffness and infill walls contribute lateral stiffness.
A bilinear model of stiffness is established. Columns and infill enter the
inelastic zone at the same time. Natural frequencies are determined byapplying free vibration.

2. MODELING OF FRAME
Response of buildings to earthquake varies for their height, infill condition,and structural irregularity. To get an idea how they perform, building framesof different story levels and infill conditions have to be analyzed.
3 bay 6 story, 10 story and 15 story building frames have been studied.
Each bay is of 20 feet span. Each frame has been studied for three
conditions: with soft story, no soft story (with full infill) and with no infill.
Figure 1 shows frames of different infill conditions.

Figure 1: Frames of different infill conditions

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2.1

Mass of each story

Only dead load of structure is considered for earthquake load. Deadload is 60 psf, floor finish is 25 psf, partition wall is 20 psf. Floor
dimension is 20ft * 20ft. Dead load of each bay is 186.67 * 103 kg and massof each story is 57.14 * 103 kg.
2.2

Structural characteristics

2.2.1 Column property
Dimension of column is 350mm × 350mm and column height is
3000mm. Column behaves elastically till lateral deformation of 10mm andreach to failure at 100mm of lateral deformation. Stiffness of column inelastic zone is 23 × 106 N/m and in inelastic zone 1.08 × 106 N/m.
(Saatcioglu and Ozcebe, 1989)
2.2.2 Inelastic model
The model of hysteretic loop is taken from Chopra (1995). The only
modification is k2, which is not zero here. The model is based on force limit.
If Fy is exceeded inelastic limit starts. Figure 2 presents a hysteretic loop
showing different paths and force levels

k2

Figure 2: Hysteretic loop, showing different paths and force levels
2.2.3 Lateral stiffness of frame
Frame has 4 columns. Stiffness of column in elastic zone is 92 × 106
N/m and in inelastic zone 4.32 × 106 N/m. Infill adds stiffness to frame.
Frames with infill are assumed four times stiffer than frames without infill.
(Stafford-smith, B. and Carter, 1969, Stafford-Smith, B., 1962, StaffordSmith, B., 1966).

The Effect of Infills on The Dynamic Behavior of RC Frames

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December 2007, Dhaka, Bangladesh

2.2.4 Additional damping coefficient c
For the hysteretic loop, previously mentioned, damping is considered
for column and infill. Here, damping in ground, beam and joints is notconsidered. For these parameters an additional damping coefficient has been
considered.
Damping ratio, c = 4Dm π fn
Where, D is the damping ratio and m is the mass at each storey.
Natural frequency fn will be determined by applying free vibration to
the structures. We know the mass of each story is known. Then c of eachstory is determined.
2.3

Dynamic loading condition

6 story, 10 story and 15 story frames of different infill conditions wereanalyzed for combinations of ground accelerations and frequencies.
Ground accelerations used are: 1m/s2, 1.5m/s2, 2m/s2.
Frequencies used: 0.5Hz, 0.75Hz, 1Hz and 1.25Hz.
2.4

Initial condition

The structure is assumed to be static at the instant of application of.
dynamic load, i.e. initial velocity u and initial displacement u of thestructure and base were assumed to be zero.

3. ELASTIC ANALYSIS
Response of frames with linear stiffness to harmonic ground excitations arepresented in Figure 3. Form Figure 3(a) it can be observed that frame with
soft story acts like a two degrees of freedom system, as first story inter story
drift is too large compared to others. In Figure 3(b) it can be seen that, framewith full infill meets very small inter story drift compared to frame with softstory, even it does not exceed the elastic zone. In Figure 3(c) it can be seen
that, amplitude of inter story drift vs time graph increases with time.

Figure 3: Maximum inter story drift vs time of 10 story frame (a) with softstory (b) with infill (c) without infill

268

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Response of a building frame to ground motion depends upon thenatural frequency of the frame itself. The natural frequency of building
frame depends on various parameters. Frame height, width primarily
10
controls natural frequency. Empirically, the natural frequency is , where nnis the number of story of the building. Natural frequency further depends
upon infill condition of the frame. Frames, of same height, with soft story,
with infill and with no infill certainly possess different natural frequencies,
as infill contributes to the stiffness of the frame. Free vibration of a structure
may provide with the information of its natural frequency. For that purpose,first some initial ground movement is applied to the frame. After a certain
time external excitation (ground movement) stops, then the frame continued
to oscillate in free vibration, this can be seen in Figure 4.

Figure 4: Free vibration of 6 story frame (a) with infill (b) with soft story (c)without infill
Figure 5 shows natural frequencies of 6, 10 and 15 storied frames withdifferent infill conditions and natural frequency from the empirical formula,
10/n. Natural frequency is proportional to the square root of stiffness( f n ∝ k ). In this modeling, stiffness of a story with infill is four times
than that of story without infill. Therefore, it is apparent that natural
frequency of frame with infill should be twice of the natural frequency offrame without infill and by analysis of 6, 10 and 15 story frame this is foundto be almost true. Moreover, natural frequency of frame with soft story(ground story has no infill) is very close to the average of the previous two.
Natural frequency from the empirical formula, 10/n, is marginally higher
than that of frame without infill. Therefore, it seems that, this empiricalformula is applicable to the frames without infill.
3 .0

w i t h i n f il lw ith s o ft s to ry
w i t h n o in f ill
1 0 /nNatural Frequency (Hz)

2 .5

2 .0

1 .5

1 .0

0 .5

0 .0
3

6

9

12

15

18

S to ry N u m b e r

Figure 5: Comparison of natural frequencies of different story levels
with different infill conditions with thumb rule calculation

The Effect of Infills on The Dynamic Behavior of RC Frames269

December 2007, Dhaka, Bangladesh

Clearly, frame with infill (no soft story) performs better than framewith soft story and frame with no infill in terms of maximum inter story
drift. From Figure 6 it can be seen that maximum drift of frame with noinfill is marginally larger than that of frame with soft story, from frequency
0.5Hz to 0.75Hz. After that, the deviation keeps increasing.
The analyses were performed up to 1.25Hz for all the frames.
However, in terms of frequency ratio, i.e., the ratio of the excitation
frequency to the natural frequency of the frames, the range is different fordifferent frames. From Figure 6(b) it can be observed that actually frameswith soft-story go through larger inter-storey drift that even frames without
any infill for the same range of frequency ratio.

Frame without ininfill
Frame with soft story

Frame with infill

Frame with infill

Figure 6: Comparison of different infill conditions, linear analysis
for a 6-story frame
Figure 7 represents that for 10 storied frames, as frequency ratio getsnearer one, the rates of increase of maximum inter story drift increases due
to resonance.

Frame without infill

Frame without infill

Frame with soft story

Frame with softstory

Frame with infill
Frame with infill

Figure 7: Comparison of different infill conditions, linear analysis
for a 10-story frame
From ground frequency 0.5Hz to 1Hz (frequency ratio range 0.385 to0.77) plot of frame with full infill is linear, then increase in rate of270

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maximum inter story drift occurs, because, frequency ratio gets closer to one.
Frame without any infill is more vulnerable than frame with soft story fromfrequency .5Hz to 0.8Hz (Figure 8). Over 0.8Hz frame with soft story isvulnerable. The reason is frequency ratio of frame without infill deviatesfrom one after ground frequency 0.645Hz. Frequency ratio of frame with
soft story is 0.69 at ground motion frequency 0.75Hz. After that maximum,
inter story drift increases sharply.

Frame with soft story

Frame with
soft story

Frame without infill

Framewith infill

Frame without
infillFramewith infill

Figure 8: Comparison of different infill conditions, linear analysis
for a 15-story frame

4. INELASTIC ANALYSIS
Figure 9 shows that, in nonlinear analysis, properties of structure changewith time. Sometimes stiffness decreases significantly, which cause large
displacement. If earthquake continues, structure ultimately reaches todestruction. Moreover, damping has also effect on response of frame.

Figure 9: Response of a 10 storied frame with soft story for groundacceleration =2m/s2, frequency =1Hz (a) elastic analysis (b) inelastic
analysis without any additional damping (c) with 5% additional damping
For 6- story building Figure 10 shows that, frame without infill ismore vulnerable than frame with soft story from frequency range of 0.5Hz
to 1.25Hz. For frame with soft story, time of failure increases up to
frequency ratio 0.44, then it falls again.

The Effect of Infills on The Dynamic Behavior of RC Frames271

December 2007, Dhaka, Bangladesh

For 10-storied building frame, Figure 11 shows that, soft story
condition performs better than no infill condition like 6-story frame.
However, obviously, difference of time of failure decreases here. For framewith soft story failure time remains same from frequency 0.5 to 1.25Hz.
Then, it increases until 1Hz and then again falls. For frame without infill
failure time increases although. Irregularity in natural frequency of frames
in nonlinear analysis is responsible for these behaviors.
From Figure 12, it is apparent that for 15 storied frames, soft story
behavior is more vulnerable within frequency range 0.65 to 1.15Hz. For
frame with soft story time of failure falls in ground motion frequency
0.75Hz, then rises up to 1Hz, then again falls till 1.09Hz, which is thenatural frequency, then time of failure again increases. For frame without
infill time of failure rises gradually up to frequency 1Hz, and then begins tofall.

Figure 10: Comparison of different infill conditions, inelastic analysis
for a 6-story frame

Figure 11: Comparison of different infill conditions, inelastic analysis
for a 10-story frame

Figure 12: Comparison of different infill conditions, inelastic analysis
for a 15-story frame

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5. CONCLUSIONS
Six, ten and fifteen story building frames (linear, nonlinear with zero
damping and nonlinear with 5% damping) were analyzed for different infill
conditions. Once non-linearity is induced at some particular excitation
frequency stiffness may decrease significantly causing large displacement.
If earthquake continues, structures may ultimately lead to collapse. Natural
frequency of frame has been derived by applying free vibration. The
derivation is only possible for elastic modeling. It has been found in thepresent study that natural frequency of frame without infill is almost equal
to the natural frequency found by the empirical formula 10/n. Natural
frequency of frame with full infill is the highest, natural frequency of softstory is in-between the former cases. Vulnerability of structure not only
depends on story number but also on ground motion frequency. For somefrequency ranges frame with soft story is vulnerable and for some others
frame with soft story is more vulnerable. For all cases frame with full infill
performs the best. For all cases, frame with soft story has been found more
vulnerable for higher stories. For lower stories frame without infill has beenfound more vulnerable.
Guarantee

REFERENCES
Stafford-smith, B. and Carter, (1969), “A Method of Analysis for
Infilled Frames”, Proceedings of the Institution of Civil Engineers, vol. 44.
Stafford-Smith, B. (1962), “Lateral Stiffness of Infilled Frames,”
Journal of the Structural Division, ASCE, vol. 88.
Stafford-Smith, B., (1966), “Behavior of Square Infilled Frames”,
Journal of the Structural Division, ASCE, vol. 92.
Murat Saatcioglu, M. and Guney Ozcebe, G., (1989), “Response ofReinforced Concrete Columns to Simulated Seismic Loading”, ACI
Structural Journal, page 3.
Chopra, A. K., (1995), “Dynamics of Structures”, Pearson Education.

The Effect of Infills on The Dynamic Behavior of RC Frames273

December 2007, Dhaka, Bangladesh

274

New Technologies for Urban Safety of Mega Cities in Asia

ANALYSIS OF AXIAL VIBRATION OF
PILES IN LAYERED SOIL AND APPLICATION TO BATTER PILE FOUNDATIONSRAQUIB AHSAN
Bangladesh University of Engineering and Technology, Bangladesh
raquibahsan@ce.buet.ac.bd
JORGEN JOHANSS0NTokyo University, Japanjorgen@iis.u-tokyo.ac.jp
KAZUO KONAGAITokyo University, Japan
konagai@iis.u-tokyo.ac.jp
HIDETAKE TANAKATokyo University, Japanhidetake@iis.u-tokyo.ac.jp
ABSTRACTA Semi-analytical approach for solving the problem of interaction of apile with semi-infinite layered soil medium in axial vibration is discussed
here. An application involving the effect of both lateral and axial stiffness ofbatter piles in horizontal vibration is then presented in this paper. Modalparameters of a pier supported by batter piles are studied for different
batter angles. For smaller batter angles the predominant mode of vibration
corresponds to the mode induced by a force at the pier-top. For larger
batter angles the mode induced by ground movement becomes predominant.

1. INTRODUCTION
Many researchers have proposed different methods, both analytical andnumerical, for analyzing axial vibration of pile foundations in soil [Nogami
and Novak, 1976; Kausel and Peek, 1982; Mylonakis and Gazetas, 2002;
and Cairo et al., 2005]. In the present paper, a semi-analytical method
similar to the Thin Layered Element Method (TLEM), which was developed
by Tajimi and Shimomura (1976) for lateral vibration of piles, is presented
for axial vibration. Mizuhata et al. (1985) also presented solutions of axial
vibration of piles based on TLEM. However, the present method has been
derived independently and is validated and reported here for better
understanding of the method.
There have been very few studies regarding the effect of axial
stiffness of batter piles on structures in the event of horizontal vibration.
Tazoh et al. (1988) discussed strain distribution along the length and other275

December 2007, Dhaka, Bangladesh

important features of batter piles through seismic observation and analysis.
Ingham et al. (1999) performed non-linear dynamic analysis of a bridge bent
supported with batter piles but considered only lateral Winkler type springs
acting on the batter piles ignoring the coupling effect among the different
layers of soil. In the present paper, a pier of an existing old railway bridge
has been analyzed with a simple model. The simple model comprises of an
SDOF model of the pier, rigid pile cap and pile head stiffness as derived
from the semi-analytical method. The effect of both axial and lateral
stiffness of batter piles on the modal parameters of the pier is discussed here.
2. AXIAL VIBRATION OF A PILE IN LAYERED SOIL
In the present formulation soil is considered as an elastic medium
horizontally layered and semi-infinite in lateral extent (Figure 1). The soil
has a fixed boundary at the bottom end of the pile length.
Piler

Layer 1z

S O I L

Layer 22r0
Layer i

Layer nFigure 1: Schematic diagram of the layered pile-soil model
2.1

Soil stiffness

If ur and uz are respectively the displacements in radial and verticaldirections, wave motion equations in cylindrical coordinates for an axisymmetric problem are given by,2~(λ + 2μ ) ∂Θ + 2G ∂ωθ = ρ ∂ u2r
(1)
∂r
∂z
∂t
2
(λ + 2μ ) ∂Θ − 2G ∂ (rω~θ ) = ρ ∂ u2 z
(2)
∂z
r ∂r
∂t

where the Lamé’s constants λ and μ are complex numbers in order to takematerial hysteretic damping into account and ρ is the mass density.
The dilation Θ and rotation ω~θ are given by,∂u
1 ∂(ru r ) + z
Θ=
r ∂r
∂z
∂u
∂u
2ω~θ = r − z
∂r
∂z

276

(3)
(4)

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The displacement components of soil may be described in terms of thefollowing potential functions:⎧u r ⎫ ⎧v r ⎫ iωt(5)⎨ ⎬ = ⎨ ⎬e⎩u z ⎭ ⎩v z ⎭0 ⎤ ⎧ φ (z ) ⎫⎧v r ⎫ ⎡Η 1(2 ) (αr )
⎨ ⎬=⎢
⎬
⎥⎨
Η (02 ) (αr )⎦ ⎩W ( z )⎭⎩v z ⎭ ⎣ 0(6)where ω is the frequency of steady-state vibration and Η (j2 ) is Hankel
function of the second kind of order j. φ (z ) and W (z ) are the transformation
variables of the potential function.
Substituting the potential functions in equations 1 and 2 yields,
d 2φ
dW
2
α (λ + 2 μ )φ − μ 2 + α (λ + μ )− ρω 2φ = 0
dz
dz
2
dφ
d W
− α (λ + μ )+ α 2 μW − (λ + 2 μ ) 2 − ρω 2W = 0
dz
dz

(7)
(8)

Applying Galarkin's Method and assembling the global matrices, theabove equations are solved in the manner of an Eigen-value problem. Thereexist a total of 4n solutions of α , where n is the number of soil layers.
When radiation condition is considered, the number of appropriate Eigenvalues is 2n.
A foundation with a circular cross-section is assumed to be embedded
upright in the stratified soil. The boundary displacement components inradial and vertical directions are respectively expressed as,{Vr } = ∑ Η 1(2 ) (αr0 ){φ }α qα(9)α{Vz } = ∑ Η (02 ) (αr0 ){W}α qα

(10)

α

where, qα is the effective contribution corresponding to α .
Modal matrices can be defined as,[X] = [{φ }1 {φ}2 L{φ}2 N ][Z] = [{W}1 {W}2 L{W}2 N ]
Now,

[X]
⎡
⎢
⎡O
⎧{Vr }⎫⎨⎬ = ⎢[Z ]⎢gα⎩{Vz }⎭ ⎢ ⎢
⎢ ⎢
⎣ ⎣

⎤
⎤⎥ ~
~ }
⎥ ⎥{qα } = [J z ]{qα⎥⎥O⎥⎦ ⎥⎦

Analysis of Axial Vibration of Piles In Layered Soil and Application to Batter Pile Foundations

(11)
(12)

(13)

277

December 2007, Dhaka, Bangladesh

where, q~α = qα Η 1(2 ) (αr0 ) and g α =Η 0(2 ) (αr0 ).
Η 1(2 ) (αr0 )The global force vector can be expressed as,

⎡
⎡O
⎤⎤
1
⎢
Τ
⎢
⎥ ⎥{q
~ } = [D ]{q~ }Pzs = ⎢[B G ] [X ] + [A s ][Z ]⎢
α
α
z
α
⎥
⎥
2πr0
⎢⎣
⎥
⎢⎣
O⎥⎦ ⎦

{ }

(14)

where,[B G ]e = μ ⎡⎢1⎤⎥,
2 ⎣ − 1 − 1⎦
1

[A s ]e = 1 μH ⎡⎢2 1⎤⎥⎣ 1 2⎦

6

From equations 13 and 14,⎧{Vr }⎫⎧{Vr }⎫
Pz s = [R z ]⎨⎬⎬ = R z1 M R z 2 ⎨⎩{Vz }⎭⎩{Vz }⎭

[

{ }

]

(15)

where, [R z ] = 2πr0 [D z ][J z ] .
−1

Ignoring coupling with Vr,{P } = [R ]{V }
zs

z2

z

(16)

Equation 16 provides information regarding soil stiffness along
different depths of the pile along with the coupling among the soil layers.
2.2

Stiffness of a pile embedded in soil
The vertical force-displacement relationship of a pile can be expressedas,{P }= [K ]{w}
zp

(17)

Considering compatibility, from equations 16 and 17 one gets,[R z 2 ] + ([K ] − ω 2 [M z ]){Vz } = {Pz }(18)Equation 18 describes the pile-soil interaction. Pile head stiffness canbe obtained by solving the equation. Deformation of pile due to Inertial andkinematic interaction can also be determined.
Pile head stiffness obtained using the present method is verified withthe results obtained by Nogami and Novak (1976). Ratio between dynamic
pile head stiffness to static stiffness kdyn/kstat for varying ratios of pile length
to pile outer radius L/r0 and shear wave velocity of soil to longitudinal wave
velocity of pile vs/vpile are produced in Figures 2, 3 and 4. Here Poisson's
ratio ν of 0.4, the ratio of soil density to pile density ρ ρ p of 0.6 and278

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damping ratio D of 2% is assumed. The curves presented in Figures 2, 3 and
4 are identical with the results obtained by Nogami and Novak.
L/r0=10, ν=0.4, ρ/ρp=0.6, D=2%
Stiffness k = kdyn / kstat

1.0

0.5

/

Imaginary
Part

0.0
-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Frequency b1=ω/ωp-0.5

Real Partvs/vpile=0.01
vs/vpile=0.04
vs/vpile=0.08-1.0

Figure 2: Variation of normalized pile stiffness with frequency and soil
stiffness for very short piles
L/r0=40, ν=0.4, ρ/ρp=0.6, D=2%

1.5

Stiffness k = kdyn / kstat

Real Part

1.0

Imaginary
Part

/

0.5

0.0
0.0

0.2

0.4

0.6

0.8

Frequency b 1=ω/ωp
vs/vpile=0.01
vs/vpile=0.04
vs/vpile=0.08

-0.5
-1.0

1.0

1.2

1.4

Figure 3: Variation of normalized pile stiffness with frequency and soil
stiffness for moderately slender piles
1.4

L/r0=100, ν=0.4, ρs/ρp=0.6, D=2%/

Stiffness k =kdyn/kstat

1.2
1.0
0.8
0.6

Real Part

0.4
0.2
0.0
-0.20.0
-0.4
-0.6
-0.8

Imaginary Part
0.2

0.4

0.6

0.8

1.0

1.2

1.4

Frequency b1=ω/ωp
vs/vpile=0.01
vs/vpile=0.04
vs/vpile=0.08

Figure 4: Variation of normalized pile stiffness with frequency and soil
stiffness for slender piles

3. MODAL ANALYSIS OF A PIER WITH BATTER PILES
The orientation of the axial and lateral stiffness of a batter pile is inclined by
the batter angle. Thus as shown in Figure 5 the substructure (i.e., the pile
cap along with the pile-soil system) may be modeled with axial and lateralsprings substituted for the piles and soil. The stiffness components for the
degrees of freedom of the pile-cap can be expressed as,

Analysis of Axial Vibration of Piles In Layered Soil and Application to Batter Pile Foundations

279

December 2007, Dhaka, Bangladesh
K cap1,1 =∑ K sin θ + K cos θ
2

2

x ,i

i

z ,i

i

i

∑ (K − K )sin θ cosθ= ∑ x (K sin θ + K cos θ )K cap1, 2 = K cap2 ,1 =

x ,i

z ,i

i

i

z ,i

i

i

K cap1, 3 = K cap3,1

2

i

x ,i

2

i

i

∑ K cos θ + K sin θK=K= ∑ x (K − K )sin θ cos θK= ∑ x (K sin θ + K cos θ )K cap2 , 2 =

2

2

x ,i

i

z ,i

x ,i

z ,i

i

i

cap2 ,3

cap3, 2

i

i

i

i

2
i

cap3, 3

2

2

x ,i

i

z ,i

i

i

Figure 5: Pile cap supported with pile-head springs
The stiffness equation for the superstructure may be written as,
⎡ EA
0
0
⎢ L
⎢
12 EI
6 EI
⎧ Fz ,1 ⎫ ⎢ 0
3
LL2⎪F ⎪ ⎢
6 EI
4 EI⎪ x ,1 ⎪ ⎢0
2⎪⎪ M 1 ⎪⎪ ⎢LL⎨
⎬ = ⎢ EAF
⎪ z,2 ⎪ ⎢−00
⎪ Fx , 2 ⎪ ⎢ L
12 EI
6 EI
⎪
⎪ ⎢
− 3
− 2
⎪⎩ M 2 ⎪⎭ ⎢ 0
L
L
⎢
6 EI
2 EI
⎢ 0
⎢⎣
L
L2
⎡ K col1,1 K col1, 2 ⎤ ⎧ u1 ⎫=⎢⎥⎨ ⎬⎣K col 2 ,1 K col 2 , 2 ⎦ ⎩u 2 ⎭For harmonic vibration,⎡K col1,1 − m 1ω 2⎢⎣⎢

K col 2,1

−

EA
L
0
0

EA
L
0
0

0
12 EI
L3
6 EI
− 2
L

−

0
12 EI
L3
6 EI
− 2
L

⎤
⎥
6 EI ⎥⎥ ⎧ u z ,1 ⎫L2 ⎥ ⎪⎪
2 EI ⎥ ⎪u x,1 ⎪L ⎥ ⎪⎪ φ1 ⎪⎪⎥⎨⎬0 ⎥ ⎪u z , 2 ⎪⎥ ⎪u ⎪
6 EI ⎥ ⎪ x, 2 ⎪− 2 ⎥ ⎪⎩ φ 2 ⎪⎭L
4 EI ⎥
⎥
L ⎥⎦
0

(19)

⎤ ⎧ u 1 ⎫ ⎧0⎫⎬=⎨ ⎬K col 2, 2 + K cap − m 2 ω ⎦⎥ ⎩u 2 ⎭ ⎩0⎭
K col1, 2

2 ⎥⎨

(20)

The solution of the Eigen-value problem of equation 20 would yieldthe Eigen frequencies and corresponding normal modal vectors of thesystem.

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4. APPLICATION
The method described in Section 3 is applied to the pier-pile system of an
existing railway bridge which is located in Shizuoka prefecture in Japan.
The foundations of the bridge consist of both vertical and batter piles(Figure 6). The piles are steel piles with 254 mm outside diameter and 9 mm
thickness. Shear wave velocities of soil at different depths at the site are
given in Table 1. In order to determine the dynamic behavior of a typicalpier-pile system of the bridge some micro-tremor measurements were madeat a pile cap and a cross-girder of the bridge in the present study. From themicro-tremor measurement it was found that the predominant frequency forthe superstructure is 2.6 Hz. for longitudinal vibration and 2.4 Hz. fortransverse vibration.
At first the dynamic stiffness, both lateral and axial, of a single uprightbeam has been calculated for the specific site characteristics as explained in
Section 2. Lateral and axial impedances of a single pile are presented in
Figures 8 and 9. With the assumption that for small batter angles the pilehead impedances of a batter pile may not too different than a straight pile,for the given pile arrangement as shown in Figure 7, a modal analysis was
performed. With the assumption that the piles reached the bed-rock, thelength of the piles was taken as 44 m. The results of the modal analysis
show that the lowest modal frequency is 1.32 Hz for longitudinal vibrationand 2.32 Hz. for transverse vibration.

(a)

(b)

Figure 6: Schematic diagram of a typical pier of the bridge (a) front
elevation (b) side elevation (dimensions are in cm)

Figure 7: Pile layout of a typical foundation (dimensions are in cm)

Analysis of Axial Vibration of Piles In Layered Soil and Application to Batter Pile Foundations

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December 2007, Dhaka, Bangladesh

Table 1: Soil profile at the site of the bridge.
Depth (m)Shear wave velocity (m/s)
0 - 1.5113
1.5 – 8.082
8.0 – 19.0
76
19.0 – 25.0
61
25.0 – 31.0
81
31.0 – 41.2
116
41.2 510
The modes of vibration at these frequencies are schematically shownin Figures 10 and 11. All the displacement and rotational degrees of
freedom are nearly in-phase. The mode shows greater deformation at thepier top and clockwise rotation for rightward motion. The mode is most
likely to be induced in case of load acting at the pier top e.g., wind load. For
longitudinal vibration the predominant frequency determined by the modal
analysis is much lower than that determined by the micro-tremor
measurement. The reason is probably the present 2D model fails to consider
the significant stiffness in the longitudinal direction due to its 3D
configuration. Thus this 2D model is not appropriate for longitudinal
vibration. On the other hand, the predominant frequency in the transverse
direction as obtained by the modal analysis matches very well with themeasured value. Since the torsional rigidity of the deck and longitudinal
girders are insignificant compared to the flexural stiffness of the pier, the 2Dmodel could simulate the dynamic behavior of the system in transverse
direction.
Lateral Stiffness, Kx tf/m

16000
13800
12000

8000

4000

Real Part
Imaginary Part

0
0

10

20

30

40

50

60

70

Frequency ω rad/s

Figure 8: Lateral stiffness of a single pile of the bridge
Axial Stiffness, Kz tf/m

30000
25000
23200
20000
15000
10000

Real Part
Imaginary Part

5000
0
0

10

20

30

40

50

60

70

Frequency ω rad/s

Figure 9: Axial stiffness of a single pile of the bridge

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Figure 10: Fundamental mode shape of a typical pile-pier system of thebridge for longitudinal vibration (not in scale)Figure 11: Fundamental mode shape of a typical pile-pier system of thebridge for transverse vibration (not in scale)

3.0First Modal Frequency, Hz

1.0
2.5
0.5

2.0
1.5

0.0

1.0

First Modal Frequency
Normalized Modal Deformation at Pile Cap
Normalized Modal Rotation at Pile Cap
Normalized Modal Rotation at Pier Top

0.5

-0.5

-1.0
0.0
0

5

10

15

20

25

30

35

Normalized Modal Deformations for the first mode

To understand the effect of the inclination of the batter piles intransverse vibration, modal analyses have been performed for the same pilepier system with different batter angles of piles. The results are presented in
Figure 12. Pile inclination has the most prominent effect on pile cap
deformation. For a certain batter angle between 150 and 200, the pile cap
deformation in the first mode of vibration becomes zero. Beyond thisparticular batter angle the pile cap deformation again increases and actually
becomes out-of-phase with the pier top deformation. For greater batterangles, the pier top deformation is out-of-phase and rotations are in phasewith pile cap deformation; which means a right-ward pile cap deformation isassociated with a left-ward pier top deformation and anti-clockwise
rotations at both pier top and pile cap. Thus for greater batter angles themode of vibration induced by a force at the pile cap or by ground vibration
becomes predominant.

Batter Angle, Degree

Figure 12: Variation of modal parameters of pile-pier system with batter
angle

Analysis of Axial Vibration of Piles In Layered Soil and Application to Batter Pile Foundations

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December 2007, Dhaka, Bangladesh

Figure 13: First mode of vibration for greater batter angles

5. CONCLUSIONS
Modal analysis of a 2D model of the pile-pier system of an existing bridge
has been performed. In the present analysis both axial and lateral stiffness ofbatter piles have been considered. When compared with ambient vibration
records, the results of the modal analysis seem to agree well in the case oftransverse vibration, but not in longitudinal vibration due to significant 3D
effect. The most significant effect of the inclination of batter piles isreduction of pile cap deformation up to a certain batter angle. Beyond thisparticular batter angle when pile cap deformation becomes zero, the modeshape changes abruptly. Mode imposed by forces at the pier top is
predominant for lower batter angles. Whereas modes corresponding to thepile cap deformation is predominant for higher batter angles.

ACKNOWLEDGEMENT
The present study was conducted during a research fellowship awarded to
the first author by Japan Society for Promotion of Science (JSPS).

REFERENCES
Cairo, R., Conte, E., and Dente, G., 2005. Analysis of pile group
under vertical harmonic vibration. Computers and Geotechnics 32, 545-554.
Ingham, T. J., Rodriguez, S., Donikian, R., and Chan, J., 1999.
Seismic analysis of bridges with pile foundations. Computers and Structures
72, 49-62.
Kausel, E., and Peek, R., 1982. Dynamic Loads in the Interior of aLayered Stratum: An Explicit Solution. Bulletin of the Seismological Societyof America 72, 1459-1481.
Mizuhata, K., Kusakabe, K., and Katayama, K., 1985. Verticalvibration of floating pile by thin layer method: comparison withexperimental results. Summaries of technical papers of Annual Meeting,Architectural Institute of Japan B, 393-394 (In Japanese).
Mylonakis, G., and Gazetas, G., 2002. Kinematic pile response tovertical p-wave seismic excitation. Journal of Geotechnical andGeoenvironmental Engineering 128, 860-867.
Nogami, T., and Novak, M., 1976. Soil-pile interaction in vertical284

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vibration. Earthquake Engineering and Structural Dynamics 4, 277-293.
Tajimi, H., and Shimomura, Y., 1976. Dynamic analysis of soil
structure interaction by the thin layered element method. Transactions ofArchitecture Institute of Japan 243, 41-51 (In Japanese).
Tazoh, T., Shimizu, K., and Wakahara, T., 1988. Seismic observations
and analyses of grouped piles. Shimizu Technical Research Bulletin 7, 17-32.

Analysis of Axial Vibration of Piles In Layered Soil and Application to Batter Pile Foundations

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SEISMIC ASSESSMENT OF PILE
FOUNDED KHILGAON FLYOVER
MOHAMMAD MOSLEM UDDIN
Assistant Engineer
PWD Design Division-2, Purta Bhaban, Segunbagicha
Dhaka 1000, Bangladesh
moslem_1990@yahoo.com
MEHEDI A. ANSARY
Prof., Dept. of Civil Engg.,
BUET, Dhaka 1000, Bangladesh
TAHSIN R. HOSSAIN
Assoc. Prof., Dept. of Civil Engg.,
BUET, Dhaka 1000, Bangladesh
MUNAZ A. NOOR
Assoc. Prof., Dept. of Civil Engg.,
BUET, Dhaka 1000, Bangladesh
ABSTRACT
Khilgaon Flyover comprises three main arms-Rajarbagh, Saidabad
and Malibagh arms forming T-junction at Khilgaon road and railintersection. In addition, it has a loop at Malibagh side. The sub soil
stratum of the site is composed of Dhaka clay and is not susceptible toliquefaction under a moderate earthquake. However, recent earthquakes
like Asia-Tsunami (2004) and Kashmir Earthquake (2005) made experts
think that Bangladesh may experience a severe earthquake at any time. For
this reason, a proposed structure need to be designed considering aprobable earthquake and re-evaluation of existing structures is necessary.
In this study, seismic response of the Khilgaon flyover was investigated.
Both seismic static and dynamic analyses were performed. In both cases, atypical 26 m long simply supported span and a bored cast in situ RC pileunder a typical pier were investigated. Superstructure and substructure
were analyzed separately. In substructure, modeling equivalent Winklertype pile foundation model was used. For static analysis, Single Mode
Spectral Analysis Method as specified in AASHTO-LRFD (2004) was
adopted. In dynamic analysis, response spectrum method was adopted.
BNBC (1993) response spectrum acceleration was used as input
acceleration. Finite element software SAP2000 was used as modeling toolfor 3D analysis of superstructure as well as the substructure. Structural
responses, i.e. mode shapes, pier top deflection, pier base forces, pile top
deflection, forces at pile etc. were observed and estimated. Reinforcement
was checked as per AASHTO load combination. It is observed that static
analysis produces conservative values than dynamic analysis. In both cases,
structures were found to be safe.

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1. INTRODUCTION
From a natural hazard viewpoint, Dhaka is among the most vulnerable cities
in the world. Parts of Bangladesh including Dhaka, Chittagong and Sylhet
had been experiencing tremor from earthquake at almost regular intervalthat caused significant damage to lives and properties. A recent study
conducted by Ansary (2003) revealed that an earthquake with intensity VIII
could cause damage to up to 40 percent buildings in certain areas of Dhaka
city. Bangladesh National building Code (1993) placed Dhaka in Seismic
Zone 2 with PGA value of 0.15g. The seismic zones mentioned in thenational code were not based on analytical assessment of seismic hazard andwere mainly based on the location of historical data (Ansary and Choudhury,2004). An updated seismic zoning map based on analytical study wasrecently developed (Sharfuddin, 2001). Based on the philosophy behind theseismic zoning and experience from recent earthquake it can reasonably be
assumed that a major earthquake event in Dhaka region is capable ofproducing huge damage than that assumed in existing zoning map-BNBC
1993 (Ansary and Choudhury, 2004).
During the last five years, two flyovers namely Khilgaon flyover andMohakhali flyover were constructed. Construction of Gulistan-Jatrabari
flyover and Tongi flyover has already been started. More flyovers at
Moghbazar and Kuril are proposed. Khilgaon flyover as shown in Figure 1
is located at Khilgaon Rail and Road intersection in Dhaka city. Main Rail
track, to and from Dhaka, passes this area. Any damage to this structure will
cost huge lives and property. Main objective of this study was to investigate
the behavior of the Khilgaon flyover under seismic forces.

Figure 1: Aerial View of Khilgaon Flyover (From Google Earth, 2006)

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2. SOIL-STRUCTURE INTERACTION
Soil-structure interaction is very important for any kind of structure. Seismic
forces like gravity forces develop deformation in foundation resulting
changes in stresses within soil, which ultimately dictates behavior of thestructure. Two general approaches are available for rationally incorporatingsoil-structure interaction effects into structural analysis (Wolf, 1985). In the
direct method, the structure and a portion of the founding soil areincorporated in finite element modeling. Some drawbacks of this model
including the need for larger model, energy absorbing boundaries and detailsoil properties make its use prohibitive for all but most extensive analysis
demands. A simpler, more efficient approach is the “substructure method”(McGuire et al., 1998). With this method, superstructures and substructures
are analyzed separately. A simplified model for substructure is constructedthat can approximate the behavior of the soil at the foundation. This
simplified model is then coupled with structure at the supports, and structure
is analyzed. The foundation model is composed of set of structural elements,
ranging in complexity from elastic springs alone to complicated non-linear
spring/damper combinations arranged in series and/or parallel for each
degree of freedom. They are chosen based on the assumed foundation
behavior obtained either experimentally or analytically (McGuire et al.,1998).

3. METHODOLOGY
Evaluation of response of a structure in conjunction with the supporting soilpresents a challenging and multi-facetious task. The complexity of the
problem comes from the fact, that the interaction between soil and structureengenders various phenomena of different physical nature often withmutually opposing influence. The analytical and numerical approaches
applied in the engineering practice typically employ simplifying
assumptions, which preclude them from handling all these effects
simultaneously. This accounts for considerable difficulty in analyzing the
problem entirely.
In this study a detail seismic assessment of the flyover at Khilgaon rail
and road intersection was performed. Linear dynamic response spectrum
analysis was performed for a simply supported span and for a single pilefoundation under pier of the flyover considering type II soil condition andzone coefficient of 0.15. Finite element software SAP2000 (CSI, 2003) wasused as modeling tool.

4. DESCRIPTION OF THE FLYOVER
4.1

Site Conditions

Most of the part of the Khilgaon flyover rests mainly on original
Dhaka clay. Top portion of soil up to around 8 m depth is stiff to very stiff

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December 2007, Dhaka, Bangladesh

reddish brown sandy silt with clay followed by a 13 m thick (8 to 21 m)
medium to dense fine sand with silt and trace mica underlain by a very
dense light brown clayey fine sand with silt trace mica from a depth of 2125 m downward. However, topsoil up to 3.5 m at some part of main flyovercomposes of fill and organic matter and soft clay. Subsurface profiles along
Rajarbagh arm and Saidabad-Malibagh arm of main flyover at Khilgaon
flyover site are shown in Figure 2 and Figure 3 respectively.

Figure 2: Subsoil Profile along Rajarbagh side of the Flyover (Uddin, 2006)

4.2

Superstructure

Fourteen-meter wide main flyover is of 4-lanes. A concrete divider
separates two-lane roadways on each side of the centerline of the flyover.
Length of main flyover comprising 29 simply supported 22 m to 30 m longspans is about 778 m. Most of the spans are around 26 m long. Expansion
joints were provided between adjacent two spans. Lengths of main flyoverat Rajarbagh, Saidabad and Malibagh arms are 285 m, 303 m and 190 m
respectively. A typical span comprises of 0.21 m thick RC deck slab restingon 1.66 m deep pre-stressed concrete (PC) girder, which transmits loads
through RC pier cap and 2 m diameter single pier system to cast insitu RC
pile foundation. Pier caps are of 2 m constant width and varying depth
ranging between 2 m at pier-pier cap joint and 1 m at free end. Each single
pier rests on 4 to 6 nos. bored cast insitu RC piles of 0.9 m diameter and 30
m length connected with RC pile caps. Pier 1 at Rajarbagh arm near rail androad intersection comprises 1.5 m diameter two columns, each of which
rests on 4 numbers 0.61 m diameter 30 m long bored cast in situ RC piles.
This pier comprises 1.5 m deep and 1.5 m wide cap. Figure 4 shows
elevation of a typical pier bent at main flyover. A typical 2.0 m diameterpier was reinforced with 58 numbers 25 mm diameter main bars.

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Figure 3: Subsoil Profile along Saidabad-Malibagh Arm of the Flyover(Uddin, 2006)
Pre-stressed concrete girders rest on pier cap through neopreneelastomeric bearings. Single bearing of 0.55m x 0.35m x 0.091m thick was
set under each girder. A 0.05 m thick wearing coat was provided at the deck.
Pier height in main flyover varies between 5 m and 8 m. There is a loop at
Malibagh side of main flyover. Length of loop is about 477 m of whicharound 140 m is continuous RC 2.4 m deep box supported by single pier andthe rest portion is RC deck resting on PC girders, which rest on pier cap –pier system founded on piles. Loop width varies between 7 m and 8.5 m.
The expected material strengths are f’c =25 MPa for concrete of normal RC,
f’c =35 MPa for pre-stressing concrete; fy=415 MPa for mild steel and
fu =1860 MPa for high tensile wire for pre-stressing. Lengths of reinforced
earth ramps at Rajarbagh, Saidabad and Malibagh are 222 m, 220 m and 202
m respectively. Abutments at junction of main flyover and ramp rest on RC
pile foundation.
4.3

Foundation

All the piers rest on bored cast insitu 0.9 m diameter 30 m long RC
pile. Numbers of piles under all piers are not the same. Depending on load
at pier base, passage of sewerage line along or near the centerline of the
flyover at some part, 4 to 6 numbers of piles were provided at each pier.
Group of piles are connected to pier through RC pile cap. Abutments arealso rest on RC bored cast insitu pile foundation. Figure 5 shows generalpile arrangement under a typical pier at Khilgaon flyover. A 0.9 m diameter
30 m long bored cast insitu RC pile under a typical pier is reinforced with
10 numbers 25 mm diameter bars at top 7 m and the 10 numbers 20 mm
lowest 23 m.

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Figure 4: Elevation of a Typical Pier Bent (Source: DCL, 2005)

5. STATIC ANALYSIS
Adopting AASHTO-LRFD (2004) single mode spectral analysis method
forces at pier base and piles under pier of the Khilgaon flyover were
estimated. Span dead load of 6436 kN as estimated from the sectional
property of elements was used for seismic static analysis. Loads wereapplied at pier top. Pier was considered cantilever in the both longitudinal
and transverse directions. Seismic design forces at 2 m diameter 7 m highpier bases for both the directions are-base shear 868 kN and base moment6076 kN-m. Maximum pier top drift under seismic forces for either
longitudinal or transverse direction was found to be 15 mm.

Figure 5: Pile arrangements under a typical pier at Khilgaon flyover(Source: DCL, 2005)

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For determination of seismic design forces at pile, six piles under asingle pier were modeled with pile cap as plate elements. Piles weremodeled as beam element. To idealize soil support, spring constants
determined based modulus of lateral subgrade reaction of soil were imposed
at 1 m interval of the pile. SAP2000 computer software was used asmodeling tool. Seismic design forces at pier base-868 kN lateral forces and6076 kN-m moments were applied at pile cap center.
Seismic design forces in a single pile for longitudinal directions-shear
301 kN, moment 590 kN-m & axial force 715 kN and for transverse
direction-shear 302 kN, moment 576 kN-m. & axial force 1785 kN.
Maximum pile top deflection under seismic forces for either longitudinal
direction or transverse direction was found to be nine mm

6. RESPONSE SPECTRUM ANALYSIS
6.1

Superstructure Model

A typical simply supported span of the Khilgaon Flyover was selected
for 3D analyses. Model incorporates five concrete I-girders connected withrectangular RC cross beams. Girders rest on RC pier cap through neopreneelastomeric bearing. Girders are simply supported over pier caps and at thispoint, no moment in the longitudinal direction in the girder is produced. To
idealise this condition in the model, moment release was assigned at ends ofgirders. A pier cap was modeled with twelve beam elements of variable
depth to represent variable depth of the actual pier cap. Length of each beam
element in the pier is one meter. Piers are modeled as 2 m diameter circularbeam element. RC crossbeams were modeled as rectangular beam elements.
Span loads were directly applied on members. Loads on pier cap fromadjacent span were applied as point load. Fixed supports were assigned atpier base. A 3D model for a typical 26 m span superstructure is presented in
Figure 6.
Of the twelve-number of modes at modal analysis, first four
significant mode shapes of the model are presented in Figure 7. In firstmode, the deflection observed of the structure was both in transverse andvertical directions in single curvature. Transverse direction movement was
dominating. In second mode, movement observed of the structure was bothin transverse and vertical directions with predominating vertical direction
movement. In third mode, the movement observed was both in transverse
and vertical directions. Rotational movement about vertical axis wasobserved in third mode. In fourth mode, movement observed of the structure
was in vertical direction forming bow in the deck.
Seismic design forces at pier base are- longitudinal shear 835 kN andmoment 5583 kN-m, transverse shear 446 kN and moment 3554 kN. Pier
top deflections for longitudinal and transverse RS forces were found to be
15 mm and 10 mm respectively. Period of the model at first mode wasfound to be 0.7 sec.

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December 2007, Dhaka, Bangladesh

(a)

(b)

Figure 6: 3D FE model of a typical span of flyover; (a) Line diagram (b) In
filled diagram

(a)

(c)

(b)

(d)

Figure 7: First four mode shapes of a typical span; (a) 1st mode, (b) 2nd
mode, (c) 3rd mode and (d) 4th mode shapes
6.2

Pile Model

A typical 0.9 m diameter and 30 m long 6-pile group was modeled as
circular beam element. Pile cap was modeled as 1.3 m thick plate elements.
Lateral supports at 1 m interval along pile length were provided as spring
constants. Total dead load reaction at pier obtained from superstructure
model was applied at center of the cap. Of the twelve-number of modes at
modal analysis, first four significant mode shapes of the model arepresented in Figure 8. In first mode, deflection observed of the structure wasboth in longitudinal and vertical directions with predominating longitudinal
direction movement. In second mode, deflection observed was in transverse
direction in single curvature. In third mode, deflection observed was invertical direction. In fourth mode, rotational movement about vertical axis,
creating torsion in the piles, was observed.

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Forces in a single pile from RS dynamic analysis are- for longitudinal
directions-shear 212 kN, moment 442 kN-m & axial force 798 kN and fortransverse direction-shear 308 kN, moment 410 kN-m & axial force 1586
kN. Maximum pile top deflection for either longitudinal or transverse
direction was found to be 6 mm. Period of the model was found to be 0.3
sec.

(a)

(c)

(b)

(d)

Figure 8: Mode shapes of typical a 6-pile group under pier of the flyover(a) 1st mode, (b) 2nd mode, (c) 3rd mode and (d) 4th mode shape

7. CONCLUSIONSIn this study, seismic responses of a typical span and a typical bored cast
insitu RC pile under a pier of Khilgaon flyover were assessed. SAP2000(CSI, 2003) FEM software was used as a modeling tool. BNBC (1993)
response spectra with soil type II was used as input acceleration. Later theseresults from dynamic analysis were compared with the results fromAASHTO’s static single mode spectral analysis method. It is observed thatstatic method produces higher forces at both pier and pile. The flyover
structure was found to be safe under seismic forces.

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REFERENCES
AASHTO, 2004 LRFD Flyover Design Specification, SI Units, 3rd Edition,
American Association of State Highway and Transportation Officials,
Inc., Washington, D.C.
Ansary, M.A. 2003. Economic Loss of Dhaka due to an Earthquake ofIntensity VIII, Insurance Journal of Bangladesh, Vol. 54, pp. 107-133.
Ansary, M.A. and Choudhury, J. R., 2004), Risk due to natural disasters in
Dhaka city and measures for mitigation, Fourth International
Workshop on Seismic Analysis in the South Asia Region, 12-15
September 2004, Dhaka, Bangladesh. Pp. 23-35.
Choudhury, J.R. and Ali, H. 1992. Assessment of Seismic Hazard in
Bangladesh.
Computers and Structures, Inc., SAP2000, Version 8.1, Integrated
Structural Analysis and Design Software. Berkeley, CA, 2000.
Development Constructions Ltd. 2005. As Built Drawings, Construction of
Flyover at Khilgaon Rail and Road Intersection in Dhaka City, House
No. 11, Road No. 19A, Sector No. 4, Uttara, Dhaka, Bangladesh.
HBRI and BSTI 1993. Bangladesh National Building Code, BNBC 1993
Dhaka, Bangladesh
McGuire, J.W., Cannon, I.B.S., Cofer, W.F. and McLean, D.I. 1998.
Seismic evaluation of pile-founded highway flyover on saturated Peat
Journal of structural engineering, ASCE, 124 (1), pp. 71-79.
Sharfuddin, M. 2001. Earthquake Hazard Analysis for Bangladesh, M.Sc.
Engg. Thesis, Department of Civil Engineering, Bangladesh
University of Engineering and Technology, Dhaka, Bangladesh.
Uddin, M. M 2006. Assessment of Khilgaon Flyover under Seismic Load, M.
Engg. Thesis, Department of Civil Engineering, Bangladesh
University of Engineering and Technology, Dhaka, Bangladesh

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PROPOSAL OF A METHODOLOGYTO DESIGN PP-BAND MESHESTO RETROFIT LOW EARTHQUAKERESISTANT HOUSESPAOLA MAYORCA and KIMIRO MEGURO
International Center for Urban Safety Engineering
Institute of Industrial Science, the University of Tokyo
paola@iis.u-tokyo.ac.jp
ABSTRACTPast earthquakes have shown that the collapse of seismically weak
adobe/masonry structures is responsible for most of the fatalities indeveloping countries.
It is, thus, urgent to improve their seismic
performance in order to reduce future fatalities and to protect the existing
housing stock. To encourage seismic retrofitting, inexpensive and easy to
implement technical solutions are desirable. Retrofitting by polypropylene
band (PP-band) meshes satisfies these requirements. These bands
commonly used for packing are resistant, inexpensive, durable andworldwide available.
Experiments and advanced numerical simulations have shown that
PP-band meshes can dramatically increase the seismic capacity of
adobe/masonry houses. Nevertheless, a simple yet accurate design method
is still needed to optimize the mesh arrangement and assess its performance.
PP-band meshes increase the structure ductility and energy dissipation
capacity through controlled structure cracking. Therefore, it is very
important to calculate transient and permanent displacements so thatdamage level and eventual repaired cost can be estimated.
In order to develop a simple methodology to design PP-band meshretrofitting, time history responses of several PP-band retrofitted
adobe/masonry structures subjected to different strong ground motions were
calculated and analyzed to identify the most relevant factors influencing the
behavior. The analyses showed that the most important factor controllingmaximum transient and permanent displacements was the residual strength
immediately after cracking. It is impossible to avoid cracks with PP-bandmeshes and when they occur, a strength drop is expected. It was found that
if the relation between the residual and maximum strength is above acertain value, there are no remarkable variations in the structure maximum
and transient displacements. The results obtained in this study will be used
to propose a simple methodology to design PP-band mesh retrofitting foradobe/masonry houses.

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1. INTRODUCTION
Past earthquakes have shown that the collapse of seismically weak
adobe/masonry structures is responsible for most of the fatalities indeveloping countries.
It is, thus, urgent to improve their seismic
performance in order to reduce future fatalities and to protect the existing
housing stock. To encourage seismic retrofitting, inexpensive and easy to
implement technical solutions are desirable. Retrofitting by polypropylene
band (PP-band) meshes satisfies these requirements. These bands commonlyused for packing are resistant, inexpensive, durable and worldwide available.
A simple methodology to design PP-band mesh retrofitting is yet to be
developed. This is absolutely necessary to estimate the expected structural
response, in terms of transient and permanent deformations, for a particulardemand. As a first step to develop such a design method, time history
responses for several PP-band retrofitted adobe/masonry structuressubjected to different strong ground motions are calculated and analyzed to
identify the most relevant factors influencing the structural performance.

2. MODEL USED
2.1

Model formulation

Static tests [Sathiparan et al., 2004] have shown that the shear force –lateral deformation curve of a PP-band retrofitted wall can be roughly
idealized as shown in the left curve of Figure 1. Vc and Δc correspond to theshear strength and cracking deformation of the masonry wall whereas Vr
and Kr correspond to the residual strength and stiffness after the wall
cracking. The first two parameters are mainly dependent on the masonryitself, Vr depends on both masonry and PP-band mesh and Kr depends
mostly on PP-band.

V

V

Vc
Vr

Kr

Kr

V’c
Ko

Ko

Δc

Δ

Δ’c

Δ

Figure 1: Idealization of shear force versus lateral deformation for amasonry wall retrofitted with PP-band mesh
To perform the non-linear time-history analysis, the force-deformation
curve is further idealized as shown on the right side graph. This

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simplification is assumed to be conservative as a fraction of the wallstrength is not considered. In the graph:
Vr − K r Δ o
Ko − Kr(1)

Ko(Vr − K r Δ o )Ko − Kr(2)

Δ' c =
V 'c =

To perform the cyclic analysis a hysteresis rule is necessary. For thispurpose, a Modified Clough model, i.e. with degrading stiffness, was chosen
for this study.
2.2

Model verification

The model was verified with available experimental data. The
parameters considered are shown in the table below.
Table 1: Material properties
Parameter
Value
Ko [kN/mm]
5.00
Kr [kN/mm]
-0.20
6.40
Δ’c [mm]Figure 2 shows the comparison between the model and theexperimental results. The envelope of both curves and the reloading
branches coincide very well. Although the unloading branch is stiffer in themodel, the overall response corresponds well to the experimental
observation. It has been suggested that the hysteresis rule may not be critical
for the estimation of the structural response [Miranda, 2006]. Therefore, themodel was considered appropriate for the study.

Figure 2: Comparison of the experimental response of a wall subjected tocyclic loads with the model prediction

Proposal of A Methodology to Design Pp-Band Meshes to Retrofit Low Earthquake Resistant Houses299December 2007, Dhaka, Bangladesh

3. PARAMETRIC STUDY
PP-band meshes improve the seismic performance of adobe/masonry houses
by increasing its ductility through controlled cracking. Strength is not
drastically improved with this retrofitting methodology although some
additional strength is provided by the mortar covering.
In order to assess the seismic capacity of the retrofitted structures, it isnecessary to estimate the amount of transient and permanent displacements.
The former are important because beyond a certain limit they may lead to
unstable behavior, buckling and eventual roof collapse. The latter define
whether the structure can be reused and how much it may be necessary forrepairing it.
To estimate the expected transient and permanent displacements aswell as which parameters of the retrofitted walls (Vc, Vr, Δc, Kr) affect thesethe most, a parametric study using the model presented above was carriedout. Eighteen structures with different force deformation characteristics
subjected to three strong ground motion records were analyzed using 1-DOF
systems. Tables 2 and 3 summarize the structure and ground record
characteristics respectively.
The structural parameters were chosen so as to represent one of thetwo main walls of a 3-m high, 3-m long 1-story adobe/brick house. Threeratios of Vr/Vo were considered. These values are directly related to thevolume of PP-band mesh and how tightly it is installed on the wall. It was
experimentally determined that after applying a mortar cover on the
retrofitted wall, this ratio was close to 0.8. The ratio Kr/Ko is higher for
denser PP-mesh and was chosen null or negative based on the results ofcyclic static tests and numerical simulations.
Table 2: Material properties considered for the parametric study
Ko [kN/mm]
Vr/Vo
Kr/Ko
Parameter
Vo
[kN]
Adobe
35
10
0.50, 0.75, 1.00 0.00, -0.01, -0.02
Brick
100
50
0.50, 0.75, 1.00 0.00, -0.01, -0.02
Table 3: Strong ground motion records considered for the parametric study
PGA1) PGV2) PGD3)
Earthquake
Station[g][kine][mm]
Imperial Valley (1940)
El Centro
0.313
29.8
133.2
USGS St. 117
Loma Prieta (1989)
Capitola
0.529
36.5
91.1
CDMG St. 47125
Cape Mendocino (1992) Cape Mendocino
1.497
127.4
410.1
CDMG St. 89005
1)
Peak Ground Acceleration, 2) Peak Ground Velocity, 3) Peak Ground
Displacement

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Figure 3 shows the absolute acceleration response spectra of all thestrong ground motion records used in the parametric study. The
predominant period of a 1-story adobe/masonry structure is around 0.1 and
0.2s. The selected input motions are increasingly demanding in this range
with the Cape Mendocino Earthquake being the severest of them all.

Figure 3: Strong ground motion response spectra (Damping = 5%)
Figures 4 and 5 show the time-history response of the adobe andmasonry structures in blue line. The red line corresponds to the envelope ofthe monotonic curve. Note that the columns correspond to cases in which
Vr/Vo is constant whereas the rows correspond to cases with the same Kr/Ko.

Figure 4: Time-history response of adobe structure (Loma Prieta
Earthquake)

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Figure 5: Time-history response of brick structure (Loma Prieta
Earthquake)
3.1

Discussion

Figure 6 shows the comparison of the structural response of adobe andmasonry walls subjected to the El Centro strong ground motion record. It
can be seen that the adobe structure had larger maximum and permanent
displacements. This is because the adobe weaker structure experiences alarger ductility demand. This ductility is provided by the PP-band mesh.

(a) Adobe wall(b) Brick wall

Figure 6: Response of adobe and brick walls subjected
to El Centro strong ground motion record
The maximum and permanent displacements for each structure andstrong ground motion record are plotted in Figures 7 and 8 for adobe and302

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masonry, respectively. In the case of the Cape Mendocino strong groundmotion, some structures became unstable during the analysis and hence theresults are not plotted. As mentioned before, adobe structures have longer
maximum and permanent displacements.
It can be observed that for all the cases, the ratio Vr/Vo has more
influence on the seismic performance than Kr/Ko. If Vr/Vo is controlled, i.e.
kept over 0.75, the structural performance does not change dramaticallyeven for decreasing Kr/Ko ratios.
The maximum and permanent drifts for the adobe walls are less than
2.5% for the El Centro and Loma Prieta records. This can be considered an
acceptable performance. Although in some cases the adobe wall becomes
unstable under the Cape Mendocino strong ground motion, as long as Vr/Vo
is 1, which is possible to accomplish with a good construction quality
control, the maximum and permanent deformations are well within adequatelevels.

(a) Maximum displacements(b) Residual displacements
Figure 7: Maximum and residual displacements of adobe walls (Blue: El
Centro record, Red: Loma Prieta record, Black: Cape Mendocino record;
circle: Kr/Ko=0, diamond: Kr/Ko=-0.10, square: Kr/Ko=-0.20)

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The performance of the masonry retrofitted walls is also good withresidual displacements below 10mm for El Centro and Loma Prieta records.

(a) Maximum displacements(b) Residual displacements
Figure 8: Maximum and residual displacements of masonry walls (Blue: El
Centro record, Red: Loma Prieta record, Black: Cape Mendocino record;
circle: Kr/Ko=0, diamond: Kr/Ko=-0.10, square: Kr/Ko=-0.20)

4. CONCLUSIONS
An approach to estimate PP-band mesh retrofitted houses seismic
performance is proposed. Because PP-band mesh cannot avoid cracking, thekey issue for design is to control damage by limiting maximum and residual
displacements. Eighteen structures subjected to three strong ground motions
were analyzed. The results suggest that the most important parameter for agood seismic performance is the structure strength immediately after
cracking, Vr. Experiments have shown that it is possible to control thisparameter by providing enough density of PP-band mesh and covering theretrofitted structure with mortar.
The material model used for the analysis follows the cyclic behaviorof the structure well. However, the unloading stiffness is higher than thatobtained through experiments. Although it is not expected that this fact will

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significantly affect the results of the analysis carried out, it should be
investigated by further refining the model.
The analysis presented in this article will be used to develop a simple
design methodology for PP-band mesh retrofitting. For this purpose, it isstill necessary to evaluate the seismic performance of walls under out-ofplane conditions to verify that the meshes prevent this type of failure.

REFERENCES
Guragain, R., Mayorca P., Kawin W., and Meguro K. 2006.
Simulation of brick masonry wall behavior under in-plane cyclic loading
using applied element method, Proc. of the 8th International Summer
Symposium of JSCE, pp. 55-58.
Mayorca, P., Sathiparan, N., Guragain, R., Nesheli, N., and Meguro,
K. 2006. Seismic Behavior of Masonry Houses Retrofitted with PP-Band
Meshes Evaluated through Shaking Table Tests, Proc. of the 1st European
Conference on Earthquake Engineering and Seismology, Geneva,
Switzerland, CD-ROM.
Miranda, E., Reflections on the Use of Elastic or Secant Stiffness for
Seismic Evaluation and Design of Structure, Proc. of the 1st European
Conference on Earthquake Engineering and Seismology, Geneva,
Switzerland, CD-ROM.
Sathiparan, N., Mayorca, P., Nesheli, N., Guragain, R., and Meguro,
K. 2005. In-plane and Out-of-plane behavior of PP-band retrofitted
masonry wallettes. Proc. of the 4th International Symposium on New
Technologies for Urban Safety of Megacities in Asia, Singapore.
Pacific Earthquake Engineering Research (PEER) Center Strong
Ground Motion Database, peer.berkeley.edu/smcat/ as retrieved on Oct. 15,
2007

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MODELING NONLINEAR STRESS-STRAIN
RELATIONS OF MATERIALS
MD. RAQUIBUL HOSSAIN1, MOHAMMED SAIFUL ALAM2
SIDDIQUEE3 and SYED ISHTIAQ AHMAD4
Department of Civil Engineering, Bangladesh University of Engineeringand Technology, Dhaka 1000, Bangladesh
ABSTRACT
Mathematical modeling of nonlinear stress-strain relations ofmaterial is a major concern for simulation of nonlinear response ofstructure. Such a good stress-strain relationship is highly required for boththe monotonic as well as cyclic elasto-plastic constitutive models. In thispaper, a simple nonlinear stress-strain equation is proposed which canreasonably simulate a wide range of nonlinear stress-strain behavior. The
generated stress-strain relation has a gradient, which is continuous anddifferentiable all through the curve having a zero slope at the peak strengthstate.

1. INTRODUCTION
For the finite element analysis of materials under both monotonic as well as
cyclic loading, a good nonlinear stress-strain relationship is indispensable.
Often a simple hyperbolic equation (Konder (1963)) is used to model thestress-strain relation. Also, many models have been introduced to simulate
the nonlinear stress-strain relations such as Griffith and Prevost (1990),
Tatsuoka et al (1993), Tanak (2002), Al-Karni et al (2006) etc. Some ofthese models cannot model the initial gradient of the stress-strain relations
whereas some does not show a zero tangent at the peak strength state. Also,
some model are only limited to the hardening part of the stress-strain
relationship.
A mathematical model of nonlinear stress-strain relationship mustsatisfy several conditions like (i) the curve should have an initial gradient,(ii) it must go through the peak strength state, (iii) the corresponding
gradient of the peak state must be zero, (iv) the curve should be all throughcontinuous and differentiable, (v) a single function must be able to simulate
both the pre-peak hardening part as well as post-peak softening part.
The simple hyperbolic function like Konder (1963) cannot predict the
failure realistically though it can be forced to go through the particular pointof peak strength. Beyond the peak strength, the stress continues to increase
with increasing strain as the curve approaches to the failure condition
asymptotically. A modified hyperbolic function is proposed by Griffith andPrevost (1990) that satisfies all the four criteria cited before. But it cannot
predict the post-peak behavior and the parameters required for the function
are complicated to calculate.

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Tatsuoka et al (1993) proposed a nonlinear stress-strain relation called
General Hyperbolic Equation (GHE), which can simulate the pre-peak stressstrain behavior as well as post-peak strain softening relation with a smoothtransition at the peak state. But the GHE has a complicated formulation,
which requires a large number of parameters.
Takaka’s model can simulate a series of stress strain curves with thelimitation that it has a very stiff initially and it is not differentiable at zerostrain. The model proposed by Al-Karni et al (2006) has the ability to modelboth the hardening and softening part of the complete stress strain curvewith an initial gradient. But the model also requires several material andcalibrating parameters.
In this paper a simple nonlinear stress-strain model is proposed which
can reasonably simulate a wide range of stress-strain relations for both
hardening as well as softening parts.

2. MODEL OF NONLINEAR STRESS-STRAIN RELATIONS
The proposed model is an equation that relates the stress σ with the strain
ε as follows,σ =σpε p + a ⎛ε p + a
a ⎞⎟
⎜
ε
−
⎜ ε +a ε +a⎟
ε 2p
p
⎠
⎝

(1)

Where σ p is the peak strength and the corresponding strain is ε p anda is the material parameter which controls the shape of the curve. To findthe value of a for the hardening part of the stress strain curve, equating thederivative of the curve at ε = 0 with the initial gradient E 0 , we get,εp + a ⎛εp + a
1 ⎞⎟⎛ dσ ⎞⎜−a⎟ = E0 = σ p⎜⎜ a2
ε p + a ⎟⎠ε p2
⎝ dε ⎠ 0⎝(2)

Also from the model and its derivative we can see that it satisfies thefirst four criteria cited before.
To model the post-peak behavior, we can find the value of a byequating the equation of the curve at ε = ε r and σ = σ r we get,σr =σ pεp + a ⎛εp + a
a ⎞⎟
⎜
ε
−
r
⎜ε +a ε +a⎟
ε 2p
p
⎝ r
⎠

(3)

Where, σ r is the residual strength and ε r is the corresponding strain.

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Thus, the proposed model finally satisfies the last criterion and it is acomplete model to simulate the nonlinear stress-strain relations of materials.

3. SIMULATION OF NONLINEAR STRESS-STRAIN BEHAVIOR

From the proposed model we can see that a range of stress strain curves canbe found depending on the initial gradient, which gives various a for thehardening part of the model. As a result various hardening stress strain
curve can be simulated by varying the material parameter a. Figure 1
presents a range of simulated normalized stress strain hardening curves forvarious the material parameter a.

Figure 1: Normalized stress vs. normalized strain hardening curves forvarious a.
Similarly, we can get a range of softening curves with various material
parameter a by equating the equation of the curve at ε = ε r and σ = σ r .
Figure 2 shows a range of simulated normalized stress strain softening
curves by varying the material parameter a.

Figure 2: Normalized stress vs. normalized strain softening curves forvarious a.

Modeling Nonlinear Stress-Strain Relations of Materials

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December 2007, Dhaka, Bangladesh

Thus, the proposed model can simulate a wide range of nonlinear
stress-strain relations satisfying all the five criteria. The model parameter a
can be easily estimated from the initial modulus of elasticity, E0 for thehardening part and from the residual strength, σ r for the softening part ofmaterial response.

4. CONCLUSIONS

Most widely used hyperbolic function to simulate nonlinear stress-strain
relations has some limitations of not predicting the failure condition
realistically. A mathematical model is proposed in this paper to simulate thenonlinear stress-strain relations for both the hardening part and softening
part of material response. This model has the ability to fulfill all the fivecriteria required to model a stress-strain curve. So, a wide variety of
nonlinear stress-strain relations of material can be simulated using the
proposed model.

REFERENCES

Al-Karni, A. and Alshenawy, A., (2006), Modeling of stress-strain
curves of drained triaxial test on sand, American Journal of Applied
Sciences 3 (11), 2108-2113.
Griffith, D.V. and Prevost, J.H., (1990), Stress strain curve generationfrom simple triaxial parameters, International Journal for Numerical andAnalytical Methods in Geomechanics, Vol. 14, 587-594.
Konder, R.L., (1963), Hyperbolic stress-strain response: cohesive soils,
Journal of Soil Mechanics and Foundation Division, ASCE, 89(SM1), 115143.
Tatsuoka, F., Siddiquee, M. S. A., Park, C. S., Sakamoto, M. and Abe,F., (1993), Modeling stress-strain relations of sand, Soils and Foundations,Vol. 33, No. 2, 60-81.
Tanak, T.(2002), Elasto-plastic strain hardening-softening soil modelwith shear banding, em2002.

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ENHANCEMENT ON DISASTER
PREVENTION AND MITIGATION IN
KAOHSIUNG CITY
TAI-PING CHANG
Department of Construction Engineering, National Kaohsiung First
University of Science and Technology, Kaohsiung, Taiwan, ROC
tpchang@ccms.nkfust.edu.tw
ABSTRACTIn this project, we deal with the enhancement of disaster prevention
and mitigation in Kaohsiung city, Taiwan. To achieve this goal, the project
organization contains several groups such as natural disaster, human error
disaster, information communication and emergent medical cure team. Firstof all, we organize teamwork and plan mechanism of assistance operation,then we perform the analysis and review in Today’s Kaohsiung City as thepreliminary work. Secondly, we adopt our professional techniques to do thedisaster potential analysis and perform the analysis of possible disastercharacteristics. In due course, we assist local government on revising andenhancing Standard Operation Procedure (SOP) and assist local
government on disaster reflection. Finally, we construct the Website ofcooperation agency and do educational training and technology transfer at
the same time. Furthermore, we also enhance related works for Kaohsiungcity government.

1. INTRODUCTION
Recently, National Science and Technology Center for Disaster Reduction(NCDR) in Taiwan selects some associated research institutions orlaboratories as collaborative institutions based on its regulations tocoordinate local governments on advancing disaster prevention and enhance
efficiency on disaster reflection. Therefore, both NCDR and collaborative
institutions can co-develop affairs related to disaster prevention throughcooperation and technology transfer, and strengthen capacity on local
governments’ disaster rescuers. In 2006, National Kaohsiung First
University of Science and Technology (NKFUST) was chosen as thecollaborative institution to support Kaohsiung city to enhance the disasterprevention and mitigation in Ksohsiung city. This project is executed orcooperated by nine groups: the collaborative institution, landslide disaster
team, flood team, seismic bridge damage team, seismic soil liquefaction
team, toxic disaster team, fire disaster team, technology and communication
team, and emergent medical cure team. Not only we do the disasterprevention and mitigation, but also we do educational training andtechnology transfer at the same time. Furthermore, we also enhance related
works for Kaohsiung city government.

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2. OPERATION TASKS AND PROSECUTION METHODS
We accomplish the following tasks in this project for developing the ability
on diverse disasters prevention, reaching the goal on research transfer andmitigating the damages in Kaohsiung city.
1.
2.
3.
4.
5.

Organize Teamwork and Plan Mechanism of Assistance Operation
Analysis and Review in Today’s Kaohsiung City
Perform Disaster Potential Analysis
Perform Analysis of Possible Disaster Characteristics
Assist Local Government on Revising and Enhancing Standard
Operation Procedure (SOP)
6. Assist Local Government on Disaster Reflection
7. Construct the Website of Cooperation Agency
8. Establish Emergency Medical Cure TeamIn this paper, only Mechanism for Assistance Operation (MAO),
Disaster Potential Analysis and Analysis of Possible Disaster Characteristics
are discussed in somewhat details in the following three sections. All theother operation tasks are mentioned briefly above due to the complexity andsophistication of their natures.

3. MECHANISM FOR ASSISTANCE OPERATION (MAO)
The role of National Kaohsiung First University of Science and Technology(NKFUST) is to provide some technical assistances on disaster prevention
and/or mitigation to Kaohsiung city, the complete teamwork of NKFUST on
MAO can be illustrated in Figure 1.

4. DISASTER POTENTIAL ANALYSIS
There are many kinds of disaster involved in this project, we perform thedisaster potential analysis for all of them. It is quite obvious that each typeof disaster has its own importance in some particular areas, but we can’t
present the potential analysis for all the types of the disaster in this paper.
Therefore, here we merely select a few significant disasters in
Kaohsiung city for demonstration, the complete disaster potential analysisof all the types of disaster can be found in our project report. To accomplish
all the tasks, not only we adopt the most updated professional techniquesand concepts, but also we follow all the rules and restrictions in accordancewith the regulations established by Kaohsiung city.

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Teamwork of NKFUST on MAO
NKFUST ResearchTeam
Cooperating with local research
institutes in Kaohsiung City

Task force on
emergency cure

Task force onlandslide

Task force on flood

technology system

Task force onliquefaction

Task force on bridge
accident

Task force on fire
accident

Task force on toxic
accident

Information

Mitigation
administrative
system

Education
ProgramFigure 1: Teamwork of NKFUST on MAO
4.1

Typhoon-Flood disaster potential evaluation

This project uses four different kinds of precipitations (150mm,
300mm, 450mm, 600 mm) to do the simulation for the flood area and flood
depth along the Love River in Kaohsiung city. According to our analysis,
the above precipitations are daily deluge about 1.1 years, 5 years, 20 years
and 100 years return period respectively in Kaohsiung city. In addition, weinvestigate the influence due to tide, precipitation, drainage and pumping
stations along Love River. According to the collected GIS information,
when the precipitation is under 150mm per day, the area near Love-river has
high flood potential as it can be seen from Figure 2; when the precipitations
are under precipitation 300mm、450mm、600mm per day, the district ofChen-gin, Shin-shi, Yenchen , Gushan and Nanjhe have high flood potential
as shown in Figure 3. The total length of rainfall drainage system inKaohsiung is planned to be 392 kilometers by the end of 2005. In 2006, thecompleted length is 378 kilometers, which is approximately 96.4% of thescheduled target. The annual precipitation in Kaohsiung is expected to be1800 mm (record for 2005 is 2821.4mm). First-level design for flood for
downtown area is 5-year return period (70.9mm/hr) while river area is 20year return period.

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December 2007, Dhaka, Bangladesh

後勁

溪

河
愛
仁
前 鎮 河

Flood potential (150mm per day)Figure 2: Flood potential analysis under precipitation 150mm per day

Flood potential(300mm per day)Flood potential(450mm per day)Flood potential(600mm per day)Figure 3: Flood potential analysis under precipitation 300mm, 450mm,
600mm per day respectively

4.2

Toxic disaster potential evaluation

The Hazardous Risk (HR) is defined as the probability of hazard
occurring per year within one Kilometer radius, which is equivalent tohazardous radius (Km) multiplied by occurring probability (1s/yr). The
hazardous risk is divided into four levels: (A) Heavy Polluted Zone：Red
Zone (HR>600) (B) Seriously Polluted Zone：Green Zone (HR>300) (C)Moderately Polluted ： Blue-Green Zone (HR>200) (D) Low Polluted

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Zone：Blue Zone (HR<20). In Figure 4, the toxic disaster potential analysis
in Kaohsiung city is performed and presented.

Hazardous Risk (4 levels)
Heavy polluted：Red zone
Seriously polluted：Green zone
Moderately polluted：Grey zone
Low polluted：Blue zone

×10-3(㎞*s/year)

Figure 4: Toxic accident potential analysis
Once the toxic disaster happened, the most important task is toevacuate the people and put them in the safe places. Our team select someemergent refuge locations and establish the data base for these locations.
The suggested refuge locations are school, park, hotel, sports gym, parking
lot and libraries, etc. The selected refuge locations are depicted in details asshown in Figure 5.

Suggested Refuge Location :School, Park, Hotel, Sports
Gym, Parking Lot andLibraries, etc.

Refuge locations in Kaohsiung City

Figure 5: Refuge locations in Kaohsiung City
4.3

Fire disaster potential evaluation

As it can be seen from Figure 6, Zuo-Ying district in Kaohsiung City
reflects high potential of fire accidents since it has become a complex area
containing houses and stores. In addition, we notice that Shan-Ming village
in Siao-Gang district ranks the second place on fire accident potential
analysis. However, the density of the population in this village is pretty low,

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December 2007, Dhaka, Bangladesh

the reason is that village and the nearby areas are the main operation area of
petrochemical industry.

Zuo-Ying district, Cai-Gong village

Siao-Gang district, Shan-Ming village

Figure 6: Fire accident potential analysis

5. ANALYSIS OF POSSIBLE DISASTER CHARACTERISTICS
For simplicity, here we only consider the features of toxic accidents and fire
accidents.
5.1

Feature of toxic accident

From 2003 to 2006, the toxic damage types in Kaohsiung are focusedon toxic leakage (47%) and fire accident (33%) as shown in Figure 7. While
analyzing the accident places, we find that non-chemical plants (35%) andtransportation accidents (35%) happen most frequently, which is presented
in Figure 8. Based on the human accident records in Kaohsiung city, thetoxic leakage (47%) and transportation accident (35%) are the top two
factors, we discover that the most possible reasons for this kind of disasterare leakage of chemical plants and leakage of chemical tank cars. Therefore,
from the disaster prevention and mitigation point of view, we should takethe most serious accident into first consideration as well as the economic
influence, etc.

From 2003 to 2006, the toxic
Othersdamage types in Kaohsiung Explosion 7%
are focus on toxic leakage
13%(47%) and fire accident(33%).

Fire Accidents
33%

Fire Accident
Leakage

Leakage47%

Explosion
OthersFigure 7: Toxic accident types

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non-chemical plants(35%) andtransportation accidents(35%) happen mostfrequently.

Experiments
4%

Others9%

Chemical Plants
17%

Non-Chemical
Plants35%

Transportation
35%
Chemical Plants
Non-Chemical Plants
Transportation
Experiments
OthersFigure 8: Distributions of toxic accident places
5.2

Feature of fire accident

While analyzing the causes of fire accidents, we can see that the
distributions are as follows: electric equipments (41%), human errors (21%),arson (15%), and unknown reasons and others (23%), which is presented in
Figure 9. In addition, we find that the 1~5th floors got on fire mostfrequently (81%), and the second would be the 6~12th floors (15%) asshown in Figure 10. General fire accidents have characteristics like growing
feature, uncertain feature and sporadic feature. Even though the percentage
of floors above 12th floors is only 4%, it still has possibility to have fire
accidents. There are many kinds of causes on fire accidents, therefore, weshould evaluate the influence on losses and investigate the past heavy casesin Kaohsiung city. We classify the following types as setting direction:(A) Fire accidents on dangerous plants and explosion.
(B) Fire accidents on business (stores, movie theater, KTV, etc.).
(C) Fire accidents on military ammunition depots.
(D) Fire accidents on special locations (old communities, markets,
temples, etc.).
(E) Fire accident on high-rise buildings.

electric equipments (41%),human errors (21%), arson(15%), and unknown
reasons and others (23%).

Candles
Cooking
Worship
Smoking
MachineDestroy
Electrical
Fire
Arson
Play Fires
Unknown
Reasons
OthersFigure 9: Causes of fire accident in Kaohsiung City during 1993-2004

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December 2007, Dhaka, Bangladesh

The 1~5th floors got on fire
most frequently (81%), andthe second would be the
6~12th floors (15%).

Figure 10: Floors on fire in Kaohsiung City during 1997-2004

6. CONCLUSIONSThe conclusions are summarized in the following:
1. This project is executed or cooperated by nine groups: the collaborative
institution, slope disaster team, flood team, seismic bridge damage team,seismic soil liquefaction team, toxic disaster team, fire disaster team,technology and communication team, and emergent medical cure team.
The tasks we do are stated in the above, besides, we do the educational
training and technology transfer at the same time. Furthermore, we alsoenhance related works for Kaohsiung city government.
2. Concerning disaster prevention project in Kaohsiung area, the revised
tasks which contains finished chapters, team works and schedule will be
tracked, arranged and designed as a form and also be delivered todifferent bureaus and agencies. Therefore, our team can make surewhether or not the project’s organization and content meet Kaohsiung
government’s need.
3. The setting of disaster prevention organization in Kaohsiung city is not
only collecting the latest information from foreign countries, but also
making an on-the-spot investigation in Japan (University of Tokyo,
Tokyo and Kobe Earthquake Memorial Hall, and disaster prevention
center in Kyoto University) in order to arrange a well-organizing
disaster prevention department.
4. This project uses four different kinds of precipitations (150mm, 300mm,
450mm, 600 mm) to do the simulation for the flood area and depth
along the Love River in Kaohsiung city. According to our analysis, theabove precipitations are daily deluge about 1.1 years, 5 years, 20 years
and 100years return period respectively in Kaohsiung city. In addition,
we investigate the influence due to tide, precipitation, drainage andpumping stations along Love River.
5. The task of integrating disaster prevention information reaches the goalof collecting disaster prevention information in Kaohsiung city, andinquiring related affairs for disaster prevention bureaus and agencies.
The website which is provided by our collaborative institutions can
support different disaster prevention staffs to apply for and becomes aninformation integrating platform.

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There are still some important tasks for future study, they are listed asfollows:
1. Organizing Teamwork and Operation Mechanism
2. Current Situation Review and Enhancing Disaster Prevention Project
3. Information Collecting and Disaster Potential Analysis
4. Support Local Government on Natural Disaster Reflection and PostDisaster Investigation
5. Information Review and Organizing Suggestions
6. Education Training and Technology Transfer
7. Effect Evaluation
ACKNOWLEDGEMENT
This work was partially supported by the National Science and Technology
Center for Disaster Reduction (NCDR) in Taiwan, Republic of China underGrant NCDR 95-A5000-CO-N004. The author is grateful for this support.

REFERENCES
Bengt Mattsson, 1997. The importance of the time factor in fire and rescue
service operations in Sweden，Fire Safety journal, vo1.29.
Daniel A. Crowl, and Joseph F. Louvar, 2003. Chemical Process Safety,
Second Edition, New Jersey, 109-162.
F. P. Lees, 1996. Loss Prevention in the Process Industries, 2nd Edition,
ISBN 0-7506-1547-8, Butterworth-Heinemann, Oxford, UK, Vol. 1:
3/12-16 .
AIChE, 1989. Guidelines for Process Equipment Reliability Data, with Data
Tables, American Institute of Chemical Engineers, 203-205.

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MODELS OF A TECHNICAL PLATFORM
FOR EMERGENCY MANAGEMENTWENGUO WENG
Center for Public Safety Research,
Tsinghua University, Beijing, 100084, P.R. China
wgweng@tsinghua.edu.cn
ABSTRACT
China government attaches much importance to public safety, and the
National Emergency Response Plan was issued by the China State Council
present a blueprint on how to prevent and deal with a variety of emergency
events including natural disasters, accidents, public health and social safety.
Technical platform is a powerful tool for dealing with emergency events
according to the Plan. One of the functions of technical platform is topredict incidents’ trend and consequence under different situations. Center
for Public Safety Research is developing a technical platform, whose models
are presented in this paper. Also we present some supports for developing
further this platform in order to continuously prefect its functions for futureuse.

1. INTRODUCTION
In the recent years, the Chinese economy has maintained a good growth,which results from the national policy of deepen reform and opening-up.
When China government pushes forward the country’s socialist
modernization drive, strengthens and improves macro-controls, andaccelerates economic restructuring, some unstable and uncertain factors areon rise. One of the most important problems is public safety (Wen, 2006).
China government is convinced that public safety is a lion in the way during
the process of creating a well-off society in an all around way. And so it
attaches much importance to public safety. The clout of public safety is that
all of the related work is human-oriented, which means the human lives aremost important in dealing emergency management.
On Jan. 8, 2006, The China State Council issued the national plan on
emergency response (China State Council, 2006), through a series of
response plans for public emergency events have been studied anddeveloped since 2003. The National Emergency Response Plan aims toincrease the government's capability to protect public, deal with unexpected
incidents, minimize the losses of the incidents, maintain social stability, andpromote the harmonious and sustainable development of the country. The
Plan stipulates that the State Council is the highest organ in the managementof emergency response. An office in charge of emergency responsemanagement will be set up by the State Council to collect information ofvarious incidents and coordinate the emergence response work.

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The National Emergency Response Plan is an all-hazards plan thatprovides the structure and mechanisms for national level policy andoperational coordination for emergency management. It can be partially or
fully implemented in the context of a threat, anticipation of a significant
event, or the response to a significant event. Selective implementation
through the activation of one or more of the system’s components allows
maximum flexibility in meeting the unique operational and informationsharing requirements of the situation at hand and enabling effective
interaction between various ministries and commissions, local, and otherentities (Fan and Su, 2005).
According to the Plan, technical platform is a powerful tool for
dealing with emergency events. There are many functions of technicalplatform, e.g. detection, monitoring, prediction, alert, decision-supporting,etc. One of the most important functions is to predict incidents’ trend andconsequence under different situations. In this paper, models of technicalplatform, developed by Center for Public Safety Research, Tsinghua
University, are presented. And in the next section, the basic functions of atechnical platform for emergency management are introduced. Section 3
gives some models of this platform in details, followed by concluding
remarks.

2. BASIC FUNCTIONS OF A TECHNICAL PLATFORM
Technical platform for emergency management is built upon for dealing
with emergency accident. We also call it as emergency response platform(ERP). With it, we not only response to emergency, but also manage daily
emergency-related things, e.g. on duty, receiving alarm, etc.
According to the National Emergency Response Plan, the emergency
response platform will provide a powerful tool to activate and implement
the emergency response plan. And so ERP is designed to make the response
operations more scientific, effective, and efficient. It is a centralized
solution for incident correlation, information sharing, resources aggregation,
disaster analysis, response and investigation of emergency incidents.
When dealing with emergency incidents, what is needed fromemergency response platform is a key problem in developing ERP. In faceof disastrous incidents, eg. flood, typhoon, earthquake, fire, hazardous gas
leak, traffic accident, SARS, terrorist attack, etc. how to effectively find andanalyze the information that we care about is one of the most important
problems that ERP must solve. And the second is how to scientifically
predict incidents’ trend and consequence, and alert as quick as possible,
under different situations such as incident location, wind speed, winddirection, weather, rainfall, leaking materials, storing pressure, total amount,material toxicity, surrounding environment, crowd, building structure,refuge area, etc. The third that EPR should solve is how to scientificallymake decision, conduct integrated coordination and effectively do operationconsidering many factors, e.g. spot situation, crowd evacuation, rescue

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organization, resource aggregation, equipment assemblage, supply, shortest
route, scheme optimization, fire fighting, and water, fuel and power supply,etc.
Based on the National Emergency Response Plan, we think the basic
functions of emergency response platform are listed below:• Risk analysis and safety evaluation;• Information gathering and analysis for emergency (data, voice,video, display, reading, identification and selection);• Development prediction and analysis of disaster;• Early-warning scheme and broadcast;• Evaluation of human evacuation and sites;• Optimization and starting of emergency response plan;• Real-time information gathering for location and emergence sites;• Dynamics emergence commander and logistic of emergency aids;• Evaluation of functionality and capability of emergence response.
It is obvious that one of the most important functions is to predict
incidents’ trend and consequence under different situations. Models would
be developed for prediction, based on which the emergency measures arecarried into execution. The prediction models, presented in the next section,
are developed according to the different disasters’ attribute and mechanism.

3. MODELS FOR EMERGENCY RESPONSE PLATFORM
It is obvious that models for predicting incidents’ trend and consequence isthe base of emergency response platform, and also an important componentof ERP. With models, ERP can provide the most important and valuable
spot to measure and monitor considering that it is impossible to monitor all
spots may trigger disaster. And it also quickly predicts the incident’s trend
and provides the accurate early-warning information, based on whichgovernment can make accurate decision and conduct successfulcommanding. According to the function of models in ERP, models can bedivided into three types. One type is for pre-disaster, which predicts thepossible occurrence of spot spreading disaster and provides the base for risk
evaluation. The second type is for during disaster, which quickly predicts
the trend of disaster and provides the guide for decision and commanding.
The third type is for post-disaster, which recurs the disaster progress andprovides the chance for checking the emergency response. Next somemodels are provided.
3.1

A Systematic Risk Analysis Model

Appropriate risk analysis approach in case of accidents is one rational
way to conduct efficient emergency response. The risk assessment
procedure is based on representing the study area in the form of a grid of‘cells’. The consequence assessment is performed by evaluating theModels of a Technical Platform for Emergency Management323

December 2007, Dhaka, Bangladesh

individual risk of each cell and aggregate weighted risk of a cluster of cells.
Individual risk ( t +1IRij ) and aggregate weighted risk ( t +1 AWRij ) have been
deemed to be a function of accident intensity ( t +1 AI ij ), population density( PDij ), and population sensitivity ( PS ij ) (Ji and Weng, 2007):
t +1

IRij = f ( t +1AI ij , PS ij )

t +1

t +1

AWRij = f ( IRij , PDij , PS ij )

(1)
(2)

During accidents, the accident intensity propagates via diffusive effect,transporting effect and dissipative effect. Accident intensity spreading iscontrolled by both ‘inner factor’ and ‘outer factor’. The dynamics ofpropagation of the intensity is first controlled by the diffusive effect whichis the inner factor. This implies that intensity flux liberated from theaccident epicenter travels outwards to the adjoining cells and once each ofthese incident cells become saturated with the intensity, they in turn begin toact as new intensity sources and the intensity flux begins to diffuse fromthese cells into their respective neighborhoods. The intensity gradient is thedriving force governing this outward propagation of the intensity flux. The
intensity gradient expresses different meaning in different accidents. It
means concentration gradient in toxic gas dispersion and temperature
gradient in heat radiation and so on. According to common sense, some
accident spreading is also controlled by some outer factors. For example,
wind and terrain slope will affect the distribution of the toxic gas
concentration and temperature difference between the ambience and theaccident hazards will result in convection. Therefore, we say that theintensity propagation is also governed by the transporting effect. The
dissipation effect is also an important outer factor which perhaps changes
the style of the intensity spreading. While spreading, barriers such asbuilding, river and trees and sedimentation will weaken the accident
intensity.
According to the above analysis, the algorithm of the systematic
approach is developed, shown in Figure 1. To illustrate the application of
the systematic approach, we make simulations on a fictitious city based on
THU-CPSR city model, which is designed to simulate a real city with thescale of 5250m × 4410m. There are two commercial buildings, ten
residential buildings, one school, two workshops, three LNG gas containers
and a petrochemical industry in the city. There are river and virescence area
to separate the industry area and residential area. Therefore, the model canrepresent a complex city with a cluster of potential hazardous sources andheavy population density. The city model is shown in Figure 2. The
fictitious city is divided into uniform grids of 35m × 35m. L, M and N (seeFigure2) are potential hazardous sources which may cause pool fires. The
vulnerable areas are A, B, C, D, E, F, G, H, I and J (see Figure2) which
represent residential areas with heavy population. A hypothetical scenario isused to illustrate the application of the approach. A gasoline leak in one of
the gasholders formed a liquid pool at M and flashing of the liquid gasoline
results a pool fire. If the radiation heat at L and N exceeds the thresholdvalue (10kW/m2 is used here), derivative pool fires may happen.

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Figure 1: Algorithm for the modeling of systematic risk incorporating
multiple factors for emergency response based on cellular automata method

A-J: residential area, R: river, L- N: hazardous source, V: virescent area
Figure 2: THU-CPSR city model

Models of a Technical Platform for Emergency Management

325

December 2007, Dhaka, Bangladesh

Individual risk is analyzed and the simulation results of individual risk
contours are discussed (Figure 3). From contours of individual risk, one canobtain the real-time individual risk and the information about the
distribution of individual risk. As expected, for emergency manager,
individual risk is much more practical than accident intensity during
emergency response. For example, at t=600s and t=800s (Figure 3(b)),
although the thermal intensity in most of the residential area is more than 1
kW/m2, but the individual is much less than 1 × 10-6. Therefore, the manager
can easily judge that at this time most of residential areas are safe (we thinkthat the individual risk less than 1×10-6 is safe). At t=1200s (Figure 3(c)),
the individual risk around building G is more than 1×10-6, and the area is not
safe anymore. With time going by, the unsafe area expands gradually. At
t=2600s (Figure 3(d)), almost all of the residential buildings are indangerous state except building A. Besides, according to the contours ofindividual risk, emergency managers can issue pre-warning information to
guide the people to evacuate. If one neglects tertiary accident, it is a goodstrategy to guide people to evacuate to the northwest area. However, a highrisk source L exists in the north and it will cause accident at t=1425s.
Comprehensively considering these factors, a West side evacuation isstrongly recommended (Figure 3(e) and Figure 3(f)). Aggregated weighted
risks in the ten residential areas were also computed at different time. The
results are given in table 1. Some significant conclusions can be obtained tohelp emergency managers allocate emergency rescue resources. Social
factors such as population sensitivity are important for emergency response.
For example, the AWR is very low in all the ten areas at t=600s and t=800s.
At t=1200s and t=1600s, the AWR at area E, G and J is much higher thanthat at other areas, especially area G where the AWR is the highest. At
t=2000s, the area E become the most dangerous area. After t=2000s, nearly
almost areas have high AWR.

Figure 3: Contours of individual risk under heterogeneous conditions at
different time. At t=0, accident happened at M

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Table 2: Aggregated weighted risk in ten residential areas at different timeTime(S)
Residential
Area NO.
A
B
C
D
E
F
G
H
I
J

600s

800s

1200s

1600s

2000s

2600s

0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.004630.00000
0.00000
0.00000

0.00000
0.00000
0.00000
0.00000
0.00072
0.00000
0.078610.00000
0.00000
0.00001

0.00000
0.00000
0.00000
0.00000
0.18784
0.00008
1.467590.00000
0.00006
0.015150.00000
0.00000
0.00000
0.001114.60475
0.01596
9.166490.000070.02229
1.311350.00000
0.032977
0.000070.20018
98.56041
0.70950
35.34787
0.018811.2245124.86859

0.0580170.69564
0.4526434.11988
1126.08296
27.93128115.56289
3.57464
46.84007
316.95609

Based on above analysis, the following resources allocation strategy isadvised: (1) at the first half an hour of emergency response, more rescue
resources should be sent to E, G and J. (2) after that, D, F, H and I graduallyneed more resources.
3.2

A Fire Spread Model for Old Towns

Old towns like Lijiang City have enormous historic, artistic andarchitectural values. The buildings in such old towns are usually made ofhighly combustible materials, such as wood and grass. If a fire breaks out, it
will spread to multiple buildings. In this fire spread model based on cellular
automata (Gao and Weng, 2007), the analysis area is divided into equal size
grids called cells. Older areas usually have narrow streets and densely-built
houses. In Lijiang City, houses are generally 4 to 7 m long and 2 to 4 m
wide. The streets are generally 3 m wide. The streams running through town
are about 3 m wide. The numerical accuracy and computational efficiency
were balanced with 3 m by 3 m cells in this study.
The city fire spread model advanced in Ref. (Murosaki et al., 1984)
showed that the building materials, the weather conditions and the regional
characteristics most strongly affect the fire spread. These three factors were
defined on based on the special characteristics of Lijiang City. The
buildings in Lijiang City are classed as: (1) wooden buildings having 1, 2, 3
or 5 floors, (2) earthen buildings having 1, 2 or 3 floors, (3) brick buildings
having 1, 2 or 3 floors, (4) brick and steel buildings having 1 to 7 floors, (5)steel buildings having 2 to 8 floors, and (6) other buildings like canchas,
toilets and unoccupied buildings. The different buildings have different
building structure parameters S and ratios of wood P . Besides the
structural factors, the different buildings tend to catch fire in different ways.
The equation given in Ref. (Wakamatsu, 1878) was used to calculate p (tckl ) :Models of a Technical Platform for Emergency Management327

December 2007, Dhaka, Bangladesh

0.2t2 − 4.2t1
⎧ 4.0
+
t
ckl
⎪t − tt2 − t1⎪2 1
p(tckl ) = ⎨5.0⎪(−t + t )⎪⎩ 4(t2 − t1 ) ckl 2

t −t
t1 ≤ tckl ≤ 2 1 + t1
5
t2 − t1+ t1 ≤ tckl ≤ t2
5

(3)

t1 = (3 + 3a / 8 + 8d / D) /(1 + 0.1v)(4)

t2 = ( w f / 5.5) /( Aw H / Af )(5)

Where p (tckl ) is the ability of cell [ kl ] to cause the fire to spread. The
time t1 is defined as the cell [ kl ] starts burning to when it can cause the fireto spread. a is 3 m which means length of one cell. d is a unfixed variable,
which changes according to the time and conditions (Wakamatsu, 1978;
Yasuno and Nanba, 1999). D is the farthest distance that the fire can spread
for a given certain wind speed, calculated as (Jirou and Kobayashi, 1997):(6)
D = 1.15(5 + 0.5V )Where V is the wind velocity. The time t2 is defined as the time fromwhen cell [ kl ] catches fire to what it burns out. w f is the fire load. Basedon investigations, w f for wooden structures is 60.0, for earthen structures is45.0, for brick structures is 20.0 and for others structures what do not beburned is 0.0. Aw is the average opening area for doors and windows ineach floor. A f and H are the area height of each floor in one building.
The equation to the farthest fire spreading distance presented in Ref.
(Jirou and Kobayashi, 1997) is a function of only the wind velocity anddirection. The effect of west wind is shown in Figure 4. The wind effects
have 4 levels and 8 directions for 32 different wind effects (Frederic, et al.
2006). The model considers the effects of each wind effect.

(a) 0 to 1 m ⋅ s −1(b) 2 to 5 m ⋅ s −1(c) ≥ 8 m ⋅ s −1
Figure 4: Effect of western wind

Lijiang City is in a mountainous area, so the topography is certainly
not smooth. Some buildings were built near or in the mountains, so themodel must consider the fire spreading from buildings to trees in themountains and from trees to the buildings. The fire spread among trees
differs from that among buildings, so the model must consider the tree
characteristics, ground slopes, etc. The relative topography of two nearby
cells are used to describe the slopes. The topography has eight directions,
including 4 horizontal and 4 vertical directions (Geoffrey, et al. 2006). The

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parameter poij shows the effects of the slope between adjoining cells on thefire spreading. The value of poij for each cell is depended based on
topography angle with poij = 0.1 for 0-20, 0.3 for 20-40, 0.5 for 40-60, 0.7
for 60-80, 0.9 for 80-90. Higher values of poij will result in larger, stronger
fires.
The fire states in each cell are: (1) cells are unable to burn, (2) cells
are able to burn, but are not burning, (3) cells have just begun burning, but
are not yet able to spread, (4) cells are burning strongly and are able tospread, and (5) cells are burned out. The transitions between cell states havea fixed order. When the cell catches fire, the cell state transitions to state(3).Some time after the cell catches fire, the cell state changes from (3) to(5). If the cell is in state (1) or (5), the cell state never changes. The fire
spreading model must determine whether cell [ ij ] changes state from (2) to(3). The changes probability is determined by the fire spreading judgment
index Fij . Cells with different characteristics have different Fij (Frederic, etal. 2006). The index for buildings and trees are based on the weather andcell characteristics:
building rule: Fij = Sij * Pij * Wij * p (tkl ) * α * wβ(7)tree rule: Fij = Sij * Pij *Wij * p (tkl ) * poij fxi * w β(8)Here Sij is a building or tree parameter set to1.0 for wooden buildings,
0.0 for steel buildings, and between 0.0 and 1.0 for other structures. Pij is
the ratio of wood in the structures. w is wind effect in each cell which
varies from 0.0 to 0.5 according to the distance from the burning cell.
α (0< α ≤ 1) is an adjustable parameter, whose value is changed to windeffects such as slowing of the spreading velocity. β is an adjustable windparameter, which determined the range and direction of the fire spreading.
poij (0< poij <1) is the coefficient of ground slope coefficient. fxij is the
exponent of slope effect. Wij is the combustibles loading ineach cell. When
Fij is larger than a random value (0 ≤ RAN ≤ 1, whose value is chosenstochastically), the state of the cell is changed from (2) to (3), and the cell isdefined to have caught fire. When the time after catching fire is more than t1 ,the cell state is changed to state (4). When the time is more than t2 , the cellstate is changed to state (5). The results will show how the fire spreads inthe old town areas.
The model was used to simulate a fire spreading in Lijiang City as an
example of an old town. The values parameters were α =0.4, β =1.0,
D =12.0, and d =2.0. For wooden structure P =1.0, w f =60.0, for half
combustible materials P =0.8 and w f =45.0, for almost no combustible
materials P =0.5 and w f =20.0, and for no combustible materials P =0.0,

Models of a Technical Platform for Emergency Management329

December 2007, Dhaka, Bangladesh

w f =0.0. Figure 5 shows the process of fire spreading in the Lijiang old

town area. The wind was assumed to be from the east at the 4-5 level. The
light gray is burning, but has no ability to spread, the dark gray is strongly
burning and spreading, and the black represent the burned out cells. Figure5(a) means fire broken out. In Figure 5(b) the fire has spread about 110
minutes and 1170 m2 burned to ash. Here, the fire spread direction is mainly
affected by the wind direction. In Figure 5(c) at t =122 min, the fire has
spread from buildings to trees on the mountain with 1278 m2 burned out.
Once the trees catch fire, the fire spreads quickly, as shown in Figure 5(d) at
t=230 min. Thus, the fire velocity and scope depends on the cellcharacteristics and some extra conditions.

spreading areas
spreading areas( a ) t=0 min

spreading areas( b ) t=1h50minspreading areas( c ) t=2h2min( d ) t=3h50min
Figure 4 Process of fire spreading in Lijiang old town
There are many models in the technical platform for emergency
management developed by CPSR, e.g. hazardous gas leakage model, waterpollution prediction model, evaluation model for crowd evacuation, analysis
model for Avian Influenza, estimation model for explosion effect, etc. Dueto the limit of this paper, the details of these models are not presented here.
Also we can develop more and more models in the technical platform.

4. CONCLUDING REMARKSThis paper firstly introduces the National Emergency Response Plan issued
by the China State Council. Secondly the basic functions of emergency

330

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response platform (i.e. technical platform for emergency management) areprovided. According to the Plan, Center for Public Safety Research isdeveloping a technical platform. And thirdly the details of prediction modelsof this technical platform are introduced.
This presented technical platform for emergency management is justelementary form, and its models should be extended and validated. The
platform is an integration of existing technologies, and so it needs todevelop some supports for key technologies for the future technical platform
to manage more effectively emergency:• Full-scale typical disaster and multi-disaster coupling experimental
systems;• Full-scale crowd evacuation experimental systems;• Individual protective equipment experimental systems;• Mobile emergency response platform; and• Simulation computational system, etc.

Natural disasters and man-activity related incidents are common
enemy of human being, and public safety is a general problem all over theworld. International cooperation and exchange among the countries should
be enhanced, so as to jointly cope with calamity with more efficiency.
Center for Public Safety Center, as a member of the community, will makefurther efforts in public safety research and education, and hopefully
contributes to a better and safer environment for human life.
ACKNOWLEDGEMENTS

This work was sponsored by the Program for New Century Excellent
Talents in University (NCET-06-0061), Ministry of Education, the Basic
Research Foundation (110041706) of Department of Engineering Physics,
Tsinghua University, and the Scientific Foundation for Returned Overseas
Chinese Scholars, Ministry of Education.

REFERENCES

China State Council, 2006. National Emergency Response Plan. (In
Chinese)Fan, W.C. and Su, G.F., 2005. Progress in emergency management
research for a Mega-city in China. 4th International Symposium on New
Technologies for Urban Safety of Mega Cities in Asia, October 18-19,
Singapore.
Frederic M., Xavier S. and Lucile R., 2006, Fire spread experiment inMediterranean shrub: Influence of wind on flame front properties. Fire
Safety Journal, 229-235.
Gao, N. and Weng, W.G., et al., 2007, Fire Spread Model for Old
Towns Based on Cellular Automaton, Tsinghua Science and Technology.
(In Press)

Models of a Technical Platform for Emergency Management

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December 2007, Dhaka, Bangladesh

Geoffrey C., Robert K. and Robert G., 2006, Comparison of thesensitivity of landscape-fire-succession models to variation in terrain, fuelpattern, climate and weather. Landscape Ecology, 21: 121-137.
Ji, X.W. and Weng, W.G., et al., 2007, A cellular automata-based
systematic risk analysis approach for emergency response. Submitted to
Risk Analysis.
Jirou K and Kobayashi, K., 1997, Large area fire. In: Fire Institute ofJapan (eds.) Fire Handbook third edition, Tokyo, Kyoritsu Publication Co.,
Ltd. (In Japanese)
Murosaki Y, Ohnishi K and Matsumoto K., 1984. Research on
spreading factor of an urban expansion fire. Journal of the City Planning
Institute of Japan, 373-378. (In Japanese)
Wakamatsu T., 1978. The risk of fire. In: Editorial committee ofarchitectural outline (eds.) Architecture outline No. 21 theory ofarchitectural fire prevention, Tokyo, Syokokusya, 279-298. (In Japanese)Wen, J.B., 2006. Government work report. (In Chinese)
Yasuno K and Nanba, Y., 1999, City fire prevention design. In:
Horiuchi (eds.) New edition architectural fire prevention, Tokyo,
Asakurasyoten, 182-187. (In Japanese)332

New Technologies for Urban Safety of Mega Cities in Asia

THE STATE-OF-THE-ART OF DISASTER
MITIGATION AND PREVENTIONMANAGEMENT IN TAIWAN URBAN AREA
KAI-LIN HSU
Assistant Professor
Department of Construction Engineering,
National Kaohsiung First University of Science and Technology, R.O.C.
vichsu@ccms.nkfust.edu.tw
ABSTRACT
Owing to natural factors (such as global weather changes, platemovements) and man-made factors (such as population increase andconcentration, expanding urban limits caused by economic development,
massive land development, increasing urban function) in last decades, likemost regions on the world, Taiwan’s natural and man-made disasters are
happening more frequently. The causes and contents of disasters become
more complex, and losses from disasters also increase. Due to the frequent
occurrences of natural and man-made disasters, as well as a rise in losses,
government and public sector have made efforts in technology development,
legislation and application in order to strengthen disaster prevention andresponse capability. The central and local governments of Taiwan haveinvested vast resources in recent years to improve the entire system of
warning and operational response both in the technical and organizational
aspects.
For example, Chi-Chi earthquake (M 7.6) hit Taiwan on September 21,
1999, resulted in more than 2470 life losses, and more than 10billions
U.S.D. in economic losses. In addition, Typhoon Shiang-Sen swept Taiwan
with strong wind and hard rain on October 31, 2000, causing severe
flooding in Taipei and Keelung, and making a Boeing 747 explode, claiming
81 lives and causing a natural and man-made multiple disaster while
departing from the airport. With higher frequency and larger scaledisasters, preventing the happening of disasters and establishing an
emergency response system in order to achieve an efficient hazard
management have become a very important issue nowadays.
This paper will review Taiwan’s recent development in disastermanagement programs. An overview of the major programs which were
initiated after several catastrophic disasters will be given. Next,
characteristics of the programs will be presented in terms of use of existing
networks, the role of initiator, and program subjects. Finally, discussion
and suggestions for future development of the disaster management
program will be proposed.

333

December 2007, Dhaka, Bangladesh

1. INTRODUCTION
Recently, in order to promote hazard mitigation practices more
systematically, the Executive Yuan (i.e. the Cabinet) of the central Taiwan
government promulgated “Hazards Mitigation Program” in 1994 as thebasis for national and local disaster prevention tasks in Taiwan. According
to this program, Taiwan has established 4 levels of hazard mitigation
organizations at the central and local governments (including
Province/Municipality, County/City, and Township/Shiang levels) (seeFigure 1). Based on its essence, governments at all levels have their own
Hazard Mitigation Councils (HMC), and at the Central, Province/City, andCounty/City levels, Hazard Mitigation Committee and Technical Advisory
Committee have to be established under the supervision of HMC. The
Hazard Mitigation Committee is the administrative organization; while theTechnical Advisory Committee provides consulting services for different
levels of government hazards mitigation councils. Also, as the basis andreferences to hazard mitigation tasks of different levels, this program
stipulates that the Central Hazards Mitigation Council have to elaborate“Primary Hazards Mitigation Plan”, ministries under the Executive Yuan
have to put in place “Specific Hazards Mitigation Plans”, and local
governments have to put in place “Local Hazards Mitigation Plans”. When alarge scale disaster strikes, the Emergency Operation Center（EOC） will
be set up immediately in order to carry out emergency response. National
Science Council initiated a national program entitled as “National Scienceand Technology Program for Hazards Mitigation (NAPHM)” in Nov 1997

Central Level〈on a daily basis〉〈when disasters strike〉

Central Hazards
Mitigation Council

Central EOC

Hazards Mitigation
Committee

Local Level

County/City Hazards
Mitigation Council
Hazards Mitigation
Committee

Township/Shiang Hazards
Mitigation Council

Technical Advisory
Committee

County/City EOC

Technical Advisory
Committee

Township/Shiang EOC

Disaster Area

Figure 1: Hazard Mitigation System
to consolidate the efforts of various government agencies for systematicallypromoting the up-, mid-, and down-stream research coordination, and334

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integrating the research results and transfer on the practical implementation.
The related agencies would follow the guidelines of NAPHM in planningand executing programs about technology innovation and administrative
improvement. The appropriate, long-standing and constant strategies basedon the solid research outcomes could generate the profound effects on
disaster reduction. However, it is necessary to have a regular organization tocoordinate related agencies, set up long-term research goals, and develop
the application and implementation. In May 2003, the Executive Yuanannounced “Establishment Guidelines for National Science & Technology
Center for Disasters Reduction”. This center has been founded in July 2003,
with major tasks of research and development, technical supports, andapplication and implementation, making the significant impacts on hazards
mitigation in Taiwan.
Nevertheless, this program NAPHM, as well as hazard mitigation
systems and hazard mitigation plans, had faced the challenges of various
forms of disasters including natural hazards such as the loss about USD$589 million/year due to the annual average of 3.6 typhoon (e.g. Figure 2),
the serious impacts on society due to large-scale earthquake, the gradualshortage and distribution of water, etc. and man-made such as labor death
rate about 0.077/ (1,000 workers), SARS, avian influenza, etc. In particular,
the Chi-Chi earthquake on September 21, 1999, which resulted in severe
casualties and economic losses, has great impact on and exposes the
weakness of this hazard mitigation system. Therefore, to improve andenhance this system, as well as to raise the capabilities of hazard mitigationand emergency responses, have become crucial issues. Based on devastating
experiences of Chi-Chi earthquake and other severe disasters, there aremany problems drastically needed to be improved after reviewing current
disaster prevention and emergency management practices. This article will
discuss the administration’s disaster prevention and rescue system from anextensive perspective, in order to obtain the best operation process. We wish
that Taiwan will become a country that can prevent and endure disasters,
providing the citizens a carefree life, safe environment and the protection
towards their lives and property.

Figure 2: Taipei MRT damage during typhoon period due to the floodcaused by the continuous heavy rainfall.

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December 2007, Dhaka, Bangladesh

2. TAIWAN’S DISASTER RESCUE SYSTEM AND OPERATINGMECHANISM
In recent years, major problems related to hazard mitigation and emergency
response that were aggressively improved and enhanced can be divided into
three broad categories: laws and regulations, researches and practices ofscience and technology, enhancement of civilian organizations andcommunities.
2.1

Disaster prevention and rescue system

Taiwan’s disaster prevention and rescue system, as defined by theDisaster Prevention and Rescue Act, has the system divided into three tiers– the central government level, the central-ruled municipality and county
municipality level, and the local government level of townships, villages
and municipalities. Though the Disaster Prevention and Rescue Act has notenlisted administrative districts on a separate level, the Taiwan urban-areagovernments have their municipal disaster prevention and rescue systems
which are divided into a two-tier scheme, comprising of the municipal anddistrict levels. At normal times, the organization of Taiwan urban-area’s
disaster prevention and rescue system is comprised of the Taiwan urbanarea disaster prevention joint mission, the Taiwan urban-area disasterprevention and rescue commission, the Taiwan urban-area government
disaster prevention and rescue expert consulting committee and so forth. In
the event that Taiwan urban areas are at risk of major disasters, theemergency response body would be turned into corresponding organizations,which primarily comprised of the municipal and district disaster response
centers, with an emergency response task force set up within various
administration bureaus and divisions, in addition to field command center
installed at the disaster sites, and the Taiwan urban-area rescue squad. In
post-disaster rebuilding, there is the post-disaster rebuilding promotional
committee; a logistical diagram depicting how the units work together isshown as follows:
2.1.1 Disaster mitigation consultation
The disaster mitigation consultation is hosted regularly per year or if
necessary. The members who joined the consultation consist of thecommissioners of departments, the chief of districts, civil organizations,military personnel, public utility. The district disaster mitigation
consultation is held while the municipal disaster mitigation consultation was
in operation. The members who joined the district disaster mitigation
consultation are staff of the districts and the district chief is certainly
convener of the district disaster mitigation consultation.
2.1.2 Disaster prevention and rescue committee
City disaster prevention and rescue committee is the staff members
unit of disaster mitigation consultation. The chairperson is the deputy mayorof the city; vice-chairpersons are general secretary and commissioner of fire336

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department. Executive officer is one of the city counselors, all committee
members are composed of the city departments representatives, to execute
disaster preventive strategy and policy, including planning, assessment,
integration. The executive secretary is responsible to assist all affairs. The
committee set up the sections, such as unified planning section, disasteradvertising section, disaster response section, restoration section, resource
management section, etc.
2.1.3 Experts consulting committee
The Taiwan urban-area cities have set up the experts consulting
committee by law to propose consultation about the future direction. The
city mayor is the chairperson of experts consulting committee, and the
deputy-mayor is the vice chairperson. The committee members, divided intoflooding, earthquake, security, system, information sections, etc. are toreview all the execution, scientific research of disaster mitigation works.
2.1.4 Emergency operation center (EOC)
The municipal EOC is formed in the beginning or in anxiety ofdisasters happened, depending on scale and range of disasters. The mayor of
the city is the commander of EOC, and the deputy-mayor is the vicecommander. The members joining EOC are senior officials of departments,
military institutions, public utilities, etc.
2.2

Disaster prevention and rescue operating mechanism

In a move to quickly mobilize rescue units and personnel coming fromrelevant administration bureaus and divisions in the event that the city
should be at risk or under major disasters to excel an integrated disaster
rescue yield, an “Emergency disaster reporting system” has been installed at
the Bureau of Fire Administration’s disaster rescue care duty
dispatch/command center, which encompasses a rapid command reporting
system, fax transmission system, handset short-messaging reporting system,
handset priority voice communication system, wire telephone system,
exclusive disaster alert telephone and so forth that can be used to activate
the emergency reporting system in the event of a disaster and notify relevant
disaster rescue personnel to report to the disaster response center or dispatch
rescuers to disaster-hit areas to provide emergency rescue work. To
facilitate conducting emergency field rescue work in major incident anddisaster sites, a forward command center is set up depending on the state ofa disaster site that would facilitate dispatch and command in close vicinity,
where a district magistrate would head the mission as field disastercommander, in charge of commanding field crews to carry out rescue
related undertakings in life rescuing, traffic control, peripheral security
surveillance, emergency care response and so forth.

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3. DISASTER REVIEWS- TAIPEI EXPERIENCE
3.1

921 earthquake

As major earthquakes, measuring 7.3 on the Richter scale, broke out
in Chi Chi of central Taiwan at 1:47am, September 21, 1999, which thoughquite a distance away from Taipei City, it nevertheless dealt a major blow to
the city as Dong Hsing Building, had collapsed as a result of the tremors,leaving 73 dead, 14 missing, 138 injured in a catastrophic incident, marking
it the worst natural disaster in Taipei history since 1884.
Following the quakes, Taipei city suffered major power outage as thecity was besieged in complete darkness, at which point a large volume ofincident phone calls began to reach Taipei city Government bureau of fireadministration’s 119 duty dispatch center, and response centers at various
government levels had been set up immediately after, where all disaster
rescue personnel had voluntarily reported to duty without notice. To ensure
a smooth execution of various crucial rescue efforts, a three-tier zone
control had been set up at the site that helped to segregate disaster rescuers,
logistical staff, disaster-hit family members, the press and such, with aneffective integration of rescue efforts from private rescue organizations. On
day three following the quake disaster, orders were given to begin
excavating the site, coordinated with large shake and manual digging, that
aimed to screen for any life sign, layer by layer, which had led to the rescueof the Sung brothers on day still, a factual proof that the cityadministration’s rescue efforts were on track.
Table 1: Statistics on Taipei City’s 921 quake damages
Type
Incident count74 persons (including one suffering from
Human casualty
cardiac arrest prior to arriving at thehospital)
Declared missing
14 persons
Number injured and sent
138 persons
for medical treatment
Toppled buildings
3 casesHazardous buildings
23 buildings assessed as hazardous
Building found with 199 buildings
crack lines
Gas leak
213 cases
3.2

Typhoon Nari’s gale disasterWith typhoon Nari declared to invade the city on Sept. 16, 2001, toeffectively response to relevant disasters, the Taipei City Disaster Response
Center was formally set up at 8:30 am, Sept. 15 in a move to aggressively
set up disaster prevention mobilization work. Yet little than expected that as
typhoon Nari stalled and hovered over Taiwan extendedly, notwithstanding

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packing ample of precipitations, it not only broke the city’s 105 years of
meteorological records but the unrelenting torrential rains, which far
exceeded the flood prevention criteria devised for the city, had led todevastating results, as floodwaters gushed through the embankment andinundated and disabled the pumping stations, causing mudslides, landslides,
landfalls and severe damages to the mass rapid transit system (as shown in
Figure2), and threatening the lifeline of the entire city. The disaster had
caused devastating damages, leaving 27 casualties, 3 declared missing, 16
severely injured, besides unaccountable loss of property damages among
others; relevant disasters are recapped as follows,
Following the passing of typhoon Nari, to review future strategy andto ensure a rightful execution of the rebuilding work, the Taipei city
government had instilled a “Taipei city government typhoon Nari postdisaster rebuilding committee”, to assist the administration examine thecause of the disaster, review relevant disaster prevention, rescue and aids
work, an the city’s post-disaster recovery system, as well as draftingtangible improvement recommendation and providing consultation for input
in moving forward rebuilding related undertakings. In conjunction to which,committee recommendations were forwarded to relevant administration
bureaus and division that would poise to improve and strengthen the city’s
disaster prevention system; with ongoing review efforts and infrastructure
improvements, substantial progresses had been made to Taipei City’s
relevant disaster prevention system, bracing toward the objective ofrecreating the city into a disaster resistant one.
Table 2: Statistics on Typhoon Nari’s gale damages
Disaster recap
Devastations following typhoon Nari find thecity suffered over 100 landfalls of varied
magnitudes, 40 disaster spots along some 26
Slope disasters
roadways, 25 preservation zones, and around 30
endangered dwellings, with varied landfalls
along hazardous side slopes.
Collapsed roadways 232 disaster spots
Embankment
230 meters, including those along the Shertze
damages
Dao and Shia Bashien areas.
Damaged pumping
35 equipment units located in eight stations
station equipment
Shelters for disaster- Number of disaster-hit sought shelter totaled tohit residents
2,053 persons.
Severe damages are reported at some of the
MRT damages
stations along the Nankang line, Tamsui line andPannan line.
Type

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4. FUTURE VISIONS
4.1

To launch a comprehensive round-the-clock response centerTo fully grasp and utilize a host of disaster rescue information,communication, and to integrate the disaster prevention mechanism ofvarious administrative units, which would help to discern and grapple thestate of various disaster, notify relevant units and convey disasterintelligence, and to excel the center’s command, monitoring, coordination
and response functions that are crucial for completing the disaster rescue
work and minimize disaster damages, the city administration of Taiwan
urban area should have plans to launch each city disaster response center tosupport multipurpose and round-the-clock operating modes.
4.2

To induct a disaster response backup center

In lieu of an effective system as some of the fire brigades in thecentral region had collapsed at the onset of 921 earthquake in some Taiwan
cities, to curtail the city’s existing disaster command system from being
disabled in the event of a major disaster and kept from carrying out its
intended purposes, a second disaster response center and disaster rescuecommand center within some Taiwan cities need to be re-allocated as soon
as possible based on the past experience.
4.3

To strengthen a district-based disaster prevention and rescue
organization and efficiency

After 921 earthquake, many of Taiwan city mayors are more keenly
reminded of the fact that a singular rescue body from the city government
may fall short of supporting the emergency aid for the city residents in theevent of a major disaster, for the comprehensiveness and broad-based
coverage. Taken into account the fact that the district office is more familiar
with the local geology and a close-knit community tie, making it mostsuitable to assume the frontline role in disaster prevention and rescue efforts,
active efforts have been made to enlist the district offices as part of thecity’s disaster prevention and rescue system by pushing the program tobrace toward a “regional-oriented command system”. It proved to beaffective for the system after Nari typhoon, 921 earthquake, SARS
according to Taipei experience.
4.4

To draft a disaster command system’s standard ICS operatingprocedure

By referring the concept and principles of the U.S. incident command
system (ICS), and taking into account the state of the existing command andemergency rescue work, a set of standard disaster incident command system
operating procedures are to be set up in anticipation of effectively integratevarious disaster rescue manpower and resources, which is expected to instill340

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the Taiwan urban-area city administration teams with maximum combat
readiness, and enhance the rescue efficiency at disaster scenes.
4.5

To instill a multipurpose disaster prevention park

As densely populated cities within Taiwan are, the interim placementof disaster-hit residents in the event of a major disastrous incident would
emerge as a significant problem. In light of which, some Taiwan urban-areacity governments have plans allocating park reserves for appointing disasterparks for every administrative district, taken into account the characteristics
of regional environment and population structure, where it could serve as arecreational venue to the residents at normal times and for storing essential
survival rations and equipment, and be turned into an emergency shelter fordisaster-hit residents at the time of the disaster.
4.6

To instill an intelligent rescue dispatch system

As the administration’s 119 duty dispatch center remains manuallydispatched following its upgrade from a fire brigade in 1995, some Taiwan
urban-area city administrations have plans to integrate the currently leased
ANI/ALI (an incoming call and address prompting system) 119 casereporting system to its existing information management system,
anticipating to provide real-time computerized command and dispatch thatwould help to dispatch adequate manpower, equipment and devices to thedisaster site for emergency rescue within the shortest time possible.

5. CONCLUDING REMARKSIn pursuit of a sustainable yield in disaster prevention and rescue efforts, theTaiwan urban-area administrations are committed to integrating the ISO
quality control concept and in promoting various standardized fire service
tasks by mirroring the past disasters and vying to excel, under its existingdisaster prevention and rescue framework, its administration with globalized
efficiency, scientific approach, standardized implementation and rational
enforcement. In conjunction to which, the city administration is committed
to instill an ICS emergency incident command system, rated by various
types of disasters and various stages in disaster rescue, in anticipation ofdeveloping Taiwan urban areas into metropolitan areas that are disasterproof and disaster-resistant.

REFERENCES
Chen, Liang-Chun, Wang, Jieh-Jiuh & Wei, Ya-Lan, 2001. Human
Concern and Hazard Mitigation－The Brief discussion of Community-based
Hazard Mitigation, NAPHM Newsletter, Vol. 4, 1-10.
Chen, Liang-Chun, Li, Wen-Wen & Lai, Mei-Ju, 2000. The Brief
Description of the Planning Process and Contents of Hazard Mitigation Act,
NAPHM Newsletter, Vol. 2, 3-12.

The State-of-The-Art of Disaster Mitigation and Prevention Management in Taiwan Urban Area

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December 2007, Dhaka, Bangladesh

The office of NAPHM, 2000. The Brief Description of the National
Science and Technology Program for Hazards Mitigation, NAPHM
Newsletter, Vol. 1, 1-8.
Ho, Hsin-Ya & Li, Wen-Cheng, 2001. The Planning of the Second
Phase of the National Science and Technology Program for Hazards
Mitigation, NAPHM Newsletter, Vol. 4, 18-20.
Ministry of the Interior, 2000. Hazard Mitigation Act.
Ministry of the Interior, 2000. Disaster Prevention and Rescue Act.
the National Disaster Prevention and Response Council, Taiwan,
http://www.ndppc.nat.gov.tw

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EXPERIMENTAL STUDY OF FIRE
PROPAGATION IN A COMPARTMENT
WITH DIFFERENT APPROACHING WIND
CONDITIONSHONG HUANG
Institute of Industrial Science, The University of Tokyo, Japanhhong@iis.u-tokyo.ac.jp
RYOZO OOKA
Institute of Industrial Science, The University of Tokyo, Japanooka@iis.u-tokyo.ac.jp
NAIAN LIU
University of Science and Technology of China, China
liunai@ustc.edu.cn
LINHE ZHANG
University of Science and Technology of China, China
fcrane@ustc.edu.cn
ZHIHUA DENG
University of Science and Technology of China, China
SHINSUKE KATO
Institute of Industrial Science, The University of Tokyo, Japankato@iis.u-tokyo.ac.jp
ABSTRACT
In order to clarify the fire propagation process in and between
compartments under windy conditions, fire tunnel experiments in a reducedscale compartment were conducted. The approaching wind velocity was set
to 0.0, 1.5, and 3.0m/s, and the location of the fire source was changed
between the downwind corner, upwind corner and center. The temperaturesin the compartment and flame ejected from the opening were measured. The
radiation flux from the opening and the wall temperature in thecompartment were also recorded. It is found that the extinguishment time is
reduced under windy conditions. When the approaching wind velocity ishigh, the external plume is greatly inclined to the downwind side, and thearea of flame becomes wider. The non-dimensional temperature of theexternal flame was a little lower than indicated by the results of Yokoi’s
experiments without wind.

343

December 2007, Dhaka, Bangladesh

1. INTRODUCTION
A fire initialized in a compartment will spread to the neighboring
compartment and adjacent buildings by igniting the other combustible
materials and the exposed combustible surfaces. Compartment fires cangenerally be divided into the following stages: ignition and early growth;pre-flashover period; flashover; the fully developed or post-flashover
period; and finally the decay period. Numerous studies have been done toinvestigate the fire’s characteristics in these stages (e.g. Drysdale, 1998;
Rasbash, 1991; Walton and Thomas, 1995). The pyrolysis gases generated
from the combustible materials will not all burn in the compartment. Under
the ventilation dominant condition, usually in the fully developed stage, thenecessary air quantity for all pyrolysis gases to burn is not supplied, suchthat part of the pyrolysis gases are projected from the window as external
flames. This provides a mechanism for fire to spread to the upper floors andadjacent buildings (Yokoi, 1960; Thomas and Law, 1972; Tanaka, 1993).
The spread of fire damage increases notably under strong windy conditions.
Many studies on external flames in the absence of wind have been done.
Yokoi investigated the trajectory and the temperature distribution of theexternal flame from the window in several full-scale experimental fires(Yokoi, 1960). The proposed estimation method of the external flame using
the non-dimensional temperature is still in common use now. Bullen andThomas (1979) studied the effect of the fuel area on the external flame
temperature profiles. Omiya and Hori (2001) investigated the properties ofexternal flames taking into consideration the combustion of excess fuel gas
ejected from the fire compartment by conducting a small-scale fire test.
Yamaguchi and Tanaka (2005) found that the non-dimensional temperature
is independent of size and fire temperature, but is determined bygeometrical conditions.
However, the effect of external wind has hardly been considered inthese studies, including compartment fire growth in the room and external
flames. There is some research regarding the external flame characteristics
in windy conditions (Takahashi, 2006), however, a detailed fire growth
process from the initial fire to the fully developed fire in the compartment in
the presence of external wind was not examined. In this study, a reducedscale compartment fire experiment that considers the external wind has been
conducted in a fire wind tunnel. The fire growth process from the initial fireto the fully developed fire in the compartment and the external flames fromthe opening were measured, and the effect of the external wind wasanalyzed in detail.

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2. EXPERIMENTS
2.1

Fire tunnel and reduced-scale compartment model

The fire tunnel used has dimensions of 1.8 m (width) × 1.8 m (height)
× 14 m (length). Figure 1 shows the fire wind tunnel and reduced-scalecompartment model. The compartment model size is 600×600×600 mm3.
The materials of the side walls of the model are wooden cedar boards (25mm), fire-resistant boards (32-mm) and stainless steel sheets (2-mm) frominside to outside. The ceiling and the floor are made of the same fireresistant boards and stainless steel sheets. 200 mm × 200 mm windows are
opened at the center of the upwind and downwind sides of the model. 250
ml of n-heptane was used as the fuel, which was placed in a stainlesscontainer (100×100 mm2) and ignited.
Fire Wind Tunnel
× Wind velocity measuring points
600mm

3200mm

×
200mm

Model

×
300mm

×

300mm

600mm

×

WIND

300mm
300mm
300mm

Figure 1: Fire wind tunnel and reduced-scale compartment model
Thermocouple for air temp.

Fire Source

Thermocouple for wall temp.
200mm

200mm

200mm

200mm

200mm
54-56

51-53

48-50

45-47

25-28

13-16

1-4

A

y

A’
17-20

5-8

33-36

21-24

9-12

68-70

65-67

62-64

57-58 29-32

59-61

37-39

40-41

x

42-44

Measurement ID(From top to bottom)
200mm

100mm

150mm 150mm

200mm

150mm

200mm

100mm

200mm

Heat flux transducer

z
x

Fire

Figure 2: Measurement configuration

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December 2007, Dhaka, Bangladesh

2.2

Measurement

As shown in Figure 1, the approaching wind was measured at threepoints vertically on the upwind side. The uniformity of the wind speed wasconfirmed in the vertical direction. A wind velocity measurement point wasalso positioned on the upwind side of the model to monitor the windvelocity before entering the window. Hot-wire anemometers (Kanomax,KA12) were used to measure the wind velocity. Figure 2 shows a schematic
diagram of the experimental measurement configuration. The temperatures
were measured in the compartment, on the wall and outside the opening. Ktype thermocouples (φ=1 mm) were used for the temperature measurement.
The air temperatures in the compartment were measured at nine points in
the horizontal direction and at four points in the vertical direction, thus atotal of 36 points were measured. The wall temperatures were measured
uniformly on each wall at nine points (for those walls with openings, eight
points were measured). The thermocouples measuring the external flame
temperature were fixed in place using a steel lattice. A total of 48 points
were placed at 200-mm intervals. A heat flux meter (PMMT, HYJ-10) was
positioned at one point outside the model to measure the radiant heat flux
from the window. The mass loss rate of the fuel was measured by anelectronic balance (Sardorius, LA64001S) set underneath the fuel container.
2.3

Experimental cases

The experimental cases are shown in Table 1. Three approachingwind velocity conditions, 0.0 m/s, 1.5 m/s and 3.0m/s were assessed. The
fire source was changed between the upwind corner, downwind corner andcenter of the compartment. In order to facilitate verification of the flame
characteristics, the experiments were also conducted under the same
conditions, except that the side wall was made of fire-resistant glass.
Cases
Case 1Case 2
Case 3
Case 4
Case 5
Case 6
Case 7
Case 8346

Table 1 Experimental cases
Approaching wind Fire source location
velocity (m/s)
0.0Corner
1.5
Upwind corner
1.5
Downwind corner
3.0
Upwind corner
3.0
Downwind corner
0.0
Center
1.5
Center
3.0
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3. RESULTS AND DISCUSSION
3.1 Flame characteristics and temporal temperature variation in thecompartment
The pictures of the flames of the early fire in the case of windvelocities of 1.5 m/s and 3.0 m/s are shown in Figure 3. When the firesource is in the center, the flame inclined to the downwind direction. Whenthe fire source is in the upwind corner, the flame inclined to the upwind alittle towards the wall surface, whereas when the fire source is in the
downwind corner, the flame significantly inclined to the upwind direction.
This flow characteristic can be explained in Figure 3. If there is a main
steam through the opening, vortices are formed in the corners, which leads
to the inclination towards the upwind.

Downwind corner

Upwind cornera. U=1.5m/s

Center

Downwind corner

Upwind cornerb. U=3.0m/s

CenterFigure 3: Flame characteristics in early fire

Horizontal section

Figure 4: Image of the flow in the model
Furthermore, when the fire source is in the downwind corner, theflame inclined to the upwind direction more in the case of 3.0 m/s than thatin the case of 1.5 m/s, implying that a greater vortex is formed in the
downwind corner in the case of 3.0 m/s.

Experimental Study of Fire Propagation in a Compartment with Different Approaching Wind Conditions

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December 2007, Dhaka, Bangladesh

Figure 5 shows the mass loss rate of the fuel for all cases comparedwith the case where the fuel is burned in free air. It is found that the massloss rate in the compartment is much larger than in the case of free air (nowind). This can account for the heat flux from the increasing air and wall
temperature in the compartment. Faster mass loss is shown in the case of thefaster approaching wind due to the additional oxygen provided. The peak of
the lines shows the flashover of the compartment fire.
1.8
1.6
1.4
dm/dt (g/s)

U=0.0, Corner
U=0.0, Center
U=0.0, Free air

Center1.2
1
0.8

Corner

0.6
0.4

Free

0.2
0
0

100

200

300

400

500

600

700

800

Time (s)dm/dt (g/s)

1.8
1.6

U=1.5, Upwind corner
U=1.5, Downwind corner
U=1.5, Center
U=1.5, Free air

Downwind corner

1.4
1.2
1

Center

0.8
0.6
0.4
0.2

Upwind corner
Free

0
-0.2
0

100

200

300

400

500

600

700

800

Time (s)3
Downwindcorner

2.5

Center

dm/dt (g/s)

2
1.5

U=3.0, Upwind corner
U=3.0, Downwind corner
U=3.0, Center
U=3.0, Free air

Free
Upwind corner

1
0.5
0
-0.5
0

100

200

300

400

500

600

700

800

Time (s)Figure 5: Mass loss rate of the fuelAs examples of the temperature measurement in the reduced-scalecompartment, Figure 6 shows the temporal variations in the air temperature
at the measurement points 29, 5, 13 and 21 (see Figure 2), which are close
to the ceiling. Figure 7 shows the temporal variations in the wall
temperature at the measurement points 38, 46, 49 and 52 (see Figure 2). It isfound that compartment fire growth exhibited different behavior between
cases with windy and still conditions. The temperature rises, the cedar board
comprising the wall surface is gradually warmed by the fire source andreaches its ignition point, but the fire is extinguished within 15 minutes in348

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all cases in windy conditions. On the other hand, in the absence of wind, it
is not extinguished and the cedar board on the wall burns for over 20
minutes. In the case of a wind velocity of 3.0 m/s, the temperature rises
quickly, and the fire is also extinguished quickly in comparison to the 1.5m/s wind. It may be thought that the combustible gases are blown out of thecompartment and away from the wall surfaces, which are cooled by thewind. In terms of the wall surface temperature, the temperature hike at the
downwind position (point 55) is fastest in Case 1 (no wind, fire source:
downwind corner). This coincides with the fact that the flame is inclined
towards the upwind in the presence of external wind as mentioned above.
Figure 6 shows the vertical temperature distribution at measurement
points in section A-A’ in different fire source locations (see Figure 2). The
temperature at the ceiling is highest in the case where the fire source is at
the center in still conditions.
U=0.0,Corner
U=1.5,Downwind corner
U=3.0,Downwind corner
U=1.5,Center

U=1.5,Upwnwind corner
U=3.0,Upwnwind corner
U=0.0,Center
U=3.0,Center

800

Air Temperature (℃) p 29

700
600
500
400
300
200
100
0
0

200

400
Time (s)U=0.0,Corner
U=1.5,Downwind corner
U=3.0,Downwind corner
U=1.5,Center

600

800

U=1.5,Upwnwind corner
U=3.0,Upwnwind corner
U=0.0,Center
U=3.0,Center

800

Air Temperature (℃) p 5

700
600
500
400
300
200
100
0
0

200
400
Time (s)U=0.0,Corner
U=1.5,Downwind corner
U=3.0,Downwind corner
U=1.5,Center

600

800

U=1.5,Upwnwind corner
U=3.0,Upwnwind corner
U=0.0,Center
U=3.0,Center

800

Air Temperature (℃) p 13

700
600
500
400
300
200
100
0
0

200

400
Time (s)U=0.0,Corner
U=1.5,Downwind corner
U=3.0,Downwind corner
U=1.5,Center

600

800

U=1.5,Upwnwind corner
U=3.0,Upwnwind corner
U=0.0,Center
U=3.0,Center

800

Air Temperature (℃) p 21

700
600
500
400
300
200
100
0
0

200

400
Time (s)600

800

Figure 6: Temporal variations of the air temperature in the model

Experimental Study of Fire Propagation in a Compartment with Different Approaching Wind Conditions

349

December 2007, Dhaka, Bangladesh

Higher temperatures appear in the middle in the vertical direction.
This implies that the hot gas is blown out the compartment before it rises tothe ceiling. The highest temperature near the outlet and lowest temperaturenear the inlet occur in the case of an approaching wind velocity of 3.0 m/s.
From the above analysis, it can be assumed that the external wind has twocontradictory effects. One is to promote combustion within the compartment
and thus raise the temperature, the other is to blow away and dilute the
combustible gases in the compartment and decrease the temperature, or
hasten its extinguishment. Which effect predominates depends on theapproaching wind velocity, amount of fuel, and the geometry of the opening
and compartment.
U=0.0,Corner
U=1.5,Downwind corner
U=3.0,Downwind corner
U=1.5,Center

U=1.5,Upwnwind corner
U=3.0,Upwnwind corner
U=0.0,Center
U=3.0,Center

800

Wall Temperature (℃) p 38

700
600
500
400
300
200
100
0
0

200

400
Time (s)U=0.0,Corner
U=1.5,Downwind corner
U=3.0,Downwind corner
U=1.5,Center

600

800

U=1.5,Upwnwind corner
U=3.0,Upwnwind corner
U=0.0,Center
U=3.0,Center

800

Wall Temperature (℃) p 46

700
600
500
400
300
200
100
0
0

200

400
Time (s)U=0.0,Corner
U=1.5,Downwind corner
U=3.0,Downwind corner
U=1.5,Center

600

800

U=1.5,Upwnwind corner
U=3.0,Upwnwind corner
U=0.0,Center
U=3.0,Center

800

Wall Temperature (℃) p 49

700
600
500
400
300
200
100
0
0

200

400
Time (s)U=0.0,Corner
U=1.5,Downwind corner
U=3.0,Downwind corner
U=1.5,Center

600

800

U=1.5,Upwnwind corner
U=3.0,Upwnwind corner
U=0.0,Center
U=3.0,Center

800

Wall Temperature (℃) p 55

700
600
500
400
300
200
100
0
0

200

400
Time (s)600

800

Figure 7: Temporal variations of the wall temperature in the model350

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ICUS Report 27

3.2

External flame temperature

3.2.1 Non-dimensional flame temperature
Yokoi's research (Yokoi, 1960) is well known concerning thetemperature measurement of the external flame from the window in theabsence of wind. Non-dimensional temperature along the axis of theexternal flame is expressed by the equation below.

Θ = ΔT0 r05/ 3 /(T∞Q 2 / c p2 ρ 2 g )1/ 3(1)

Q = c p mout ΔT(2)

Where ΔT0 is the temperature rise at arbitrary position along the plumeaxis (K), r0 is the equivalent radius of the opening ( BH / 2π , m), B and H are
the width and height of the opening respectively, Q is the enthalpy of theejected gas (kW), ΔT is the temperature difference between the inside andoutside of the compartment (K), Cp is the specific heat (kJ/kg/K), ρ is thedensity (kg/m3), and mout is the outflow rate from the opening (m3).
The calculation of the outflow rate (mout) is as follows. When thedensity of the ambient air is larger than the density of the indoor air, that is,when ρ∞ > ρin, the outflow rate and the inflow rate which pass by each
opening can be calculated by the neutral plane height Zn using Equation (3).
Where, Hu and Hl are the height of the top and the bottom of the opening
Zn ≤ Hl

Hl < Zn < Hu

H u ≤ Zn

2
⎧
3/ 2
3/ 2
⎪ mout = α B 2 g ρ in ( ρ ∞ − ρ in ){( H u − Z n ) − ( H l − Z n ) }3⎨⎪⎩ min = 0
2⎧
3/ 2⎪⎪ mout = 3 α B 2 g ρ in ( ρ ∞ − ρin )( H u − Z n )(3)⎨⎪ m = 2 α B 2 g ρ ( ρ − ρ )( Z − H )3/ 2
in
n
l
∞
∞
⎪⎩ in 3
⎧mout = 0
⎪
⎨
2
3/ 2
3/ 2
⎪⎩min = 3 α B 2 g ρ ∞ ( ρ ∞ − ρ in ){( Z n − H l ) − ( Z n − H u ) }respectively (m), α is the opening flow coefficient (set to be 0.7 here).
Furthermore, the calculation of neutral plane height is as follows.
Figure 9 shows the pressure distribution inside and outside the compartment
when the external wind is considered. It calculates neutral plane height from
Equation (4).

Zn =Λp + pw
1, pw = C ρ∞V∞2( ρ∞ − ρin ) g2(4)

where, pw is the wind pressure on the wall surface, C is the wind pressure
coefficient (generally 0.75 and -0.3 are used for the upwind and downwind
respectively). V∞ is the approaching wind velocity. By substituting Equation(4) in Equation (3) and coupling the mass continuity equation of the outflow

Experimental Study of Fire Propagation in a Compartment with Different Approaching Wind Conditions351

December 2007, Dhaka, Bangladesh

and the inflow rate through the opening, the pressure difference ΔP between
the inside and outside can be calculated. Then, the outflow rate which passes
by the opening can be calculated. Finally, substituting Equation (2) inEquation (1), the non-dimensional temperature can be obtained.

Fire source: Center

Fire source: Downwind corner

Fire source: Upwind corner

Figure 8: Vertical distribution of air temperature in the model− ρ ∞ gz

Neutral planeZnz

Δp( z ) − ρ in gz

pin(0)

p∞ (0) + pw

Figure 9: Pressure difference between the outside and inside of thecompartment considering the external wind352

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Figure 10: Temperature rises in the external flame

Experimental Study of Fire Propagation in a Compartment with Different Approaching Wind Conditions

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December 2007, Dhaka, Bangladesh

100

z/r0

U=0.0,Corner
U=1.5,Upwnwind corner10

U=3.0,Upwnwind corner

U=1.5,Downwind corner
U=3.0,Downwind corner
U=0.0,Center
U=1.5,Center1

U=3.0,Center
Yokoi'sequation
対数
(横井式)

0.1
0.01

0.1

1

Θ

Figure 11: Non-dimensional temperature on the axis of the external flame
3.2.2 Temperature distribution and comparison with Yokoi’s results
According to the measurement of the radiant heat flux outside thecompartment, after the radiant heat flux reached its maximum, it maintained
an almost constant value for a certain period. This period is thought to be
the steady-state fully developed fire period. The average temperature risesof the external flames during this period are shown in Figure 10.
Accompanying any increase in the approaching wind velocity, theinclination of the external flame increases and the flame area becomes wider.
Concerning the temperature rise, it is found to be higher in the case where
the wind velocity is 3.0 m/s than 1.5 m/s. It is also higher when the firesource is placed in the downwind corner rather than in the upwind corner.
The non-dimensional temperature of the external flame on the flame
axis is shown in Figure 11. (z: Length on the flame axis). It agrees with theresults of Yokoi's study (Yokoi, 1960) in the case of still conditions. The
non-dimensional temperature of the ejected flame was a little lower than the
results of Yokoi’s experiments without wind.

5.

CONCLUSIONSIn this study, fire tunnel experiments in a reduced-scale compartment
were conducted in the presence of external wind in order to clarify the fire
propagation process in and between compartments under windy conditions.
The approaching wind velocity was set to 0.0, 1.5, and 3.0 m/s, and thelocation of the fire source was changed between upwind corner, downwind
corner and center. The temperatures in the compartment and of the flameejected from the opening were measured. The radiation flux from theopening and the wall temperature in the compartment were also recorded. It
is found that the extinguishment time is reduced under windy conditions.
When the approaching wind velocity is high, the ejected plume greatly
inclines to the downwind side, and the flame area becomes wider. The nondimensional temperature of the ejected flame was a little lower than the
results of Yokoi’s experiments without wind.

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ACKNOWLEDGEMENTS
This work was supported by Grant-in-Aid for Scientific Research from theJapan Society for the Promotion of Science (No. 30376636). The authors
also would like to thank Yuanfu Diao, Changshan Ding, Jian Ye, Qiong Liu
and Zhengang Zhai (University of Science and Technology of China) for
their hard work in the experiments.

REFERENCES
Bullen, M. L. and Thomas, P. H., 1979, Compartment fires with noncellulosic fuels, 17th Symposium (International) on Combustion, 11391148, The Combustion Institute, Pittsburgh.
Drysdale, D. D., 1998, An Introduction to fire dynamics, 2nd Edition, John
Wiley and Sons.
Omiya, Y. and Hori, Y., 2001, Properties of external flame taking into
consideration excess fuel gas ejected from fire compartment, Journalof Architectural Planning and Environmental Engineering, 1-8, 545.
(in Japanese)
Rasbash, D. J., 1991, Major fire disasters involving flashover, Fire Safety
Journal, 17, 85-93.
Takahashi, Y., Hayashi, Y., Kodama, N., Omiya, Y., 2006, An experimental
study on compartment fire affected by external wind, Summaries ofTechnical Papers of Annual Meeting of Architectural Institute ofJapan, 241-244. (in Japanese)
Tanaka, Y., 1993, Introduction to building fire safety engineering, Japan
Building Center.
Thomas, P. H. and Law, M., 1972, The projection of flames from buildings
on fire, Fire Research Note, No. 921.
Walton, W. D. and Thomas, P. H., 1995, Estimating temperatures incompartment fires, in SFPE Handbook of Fire Protection Engineering,
2nd Edition, 3.134-3.147, Society of Fire Protection Engineers, Boston.
Yamaguchi, J. and Tanaka, T., 2005, Temperature profiles of window jetplume, Fire Science and Technology, 24, 1, 17-38.
Yokoi, S., 1960, Study on the prevention of fire-spread caused by hot
upward current, Report of the Building Research Institute, No. 34.

Experimental Study of Fire Propagation in a Compartment with Different Approaching Wind Conditions355

December 2007, Dhaka, Bangladesh

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PROTECTIVE MEASURES OF FLOODEMBANKMENT ALONG THE JAMUNARIVER IN BANGLADESH
MD. MUNSUR RAHMAN1, MOHAMMAD ASAD HUSSAIN2,
MD. MOTAHER HOSSAIN3, MAMINUL HAQUE SARKER3 andMOHAMMAD NAZIM UDDIN*1
1
Bangladesh University of Engineering and Technology (* PhD Student),
2
Bangladesh Water Development Board and 3Center for Environmental andGeographic Information Services, Bangladesh
mmrahman@iwfm.buet.ac.bd
ABSTRACTDuring the late 1950s and mid 1960s, an earthen embankment wasconstructed, known as the Brahmaputra Right Embankment (BRE)extending for some 220km along the right bank of the Brahmaputra-Jamuna
River primarily for agricultural crop protection against flooding. Since its
construction, BRE experiences failures or damages at some vulnerable
locations resulting flooding in the adjacent land during the monsoon. To
protect the failures or damages of BRE, massive river training works areundertaken.
This paper reviews the history of river training works adopted along
BRE and their evolution towards the development of cost effective ecofriendly structures. The failures and success stories of some of the protective
measures are discussed in general. Finally, future approaches for theprotection of BRE keeping the good ecological health of the river itself are
discussed.

1. INTRODUCTION
The Jamuna River drains the rainfall and snowmelt from China, Bhutan,
India and Bangladesh. The length of the Jamuna River in Bangladesh isabout 240 km measured from its international border to the confluence with
the Ganges at Aricha. The river starts rising in March/April due to snowmelt
in the Himalayas and usually attains its peak between mid July and end of
August. The maximum discharge at Bahadurabad, the only discharge
gauging station at the Jamuna river, is estimated as 100,000m3/s. The
recorded minimum flow is 2860 m3/s. The difference in water levels
between flood and dry season is about 6.5m at Bahadurabad, which
gradually reduces in the downstream direction. The surface water slope of
the Jamuna river reduces from 7.6 cm/km at the upstream to 6.5 cm/km at
the downstream (FAP 24, 1996). The rise of water levels resulting frommonsoon discharge and mild longitudinal slopes, creates flooding on thefloodplain that often enters inside rural agricultural land, urban andindustrialized areas close to the river. During the late 1950s and mid 1960s,

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an earthen embankment was constructed, known as the Brahmaputra Right
Embankment (BRE) extending for some 220 km for agricultural crop
protection against flooding. Since its construction, BRE experiences failures
or damages at some vulnerable locations resulting flooding in the adjacentland during the monsoon. In consultation with the local people as well as
BWDB Engineers, it was understood that BRE had been retired several
times and shifted away from the main river resulting from failure or
breaches of embankment.
To protect the failures or damages of BRE, massive river
training/bank protection works are undertaken not only to reduce crop loss
due to flooding but also to ensure guard against the destruction of near byrural, urban and industrial infrastructures developed so far. Several types ofprotective works have been constructed and in some cases combination of
structures have been installed which ranges from passive measures likerevetments and hard points to partly active and passive measures likegroins/spurs. Bangladesh Water Development Board (BWDB) has mixed
experiences of both failures and successes of such projects for the protectionof BRE (Uddin, 2007).
This paper reviews the history of river training works adopted along
BRE and their evolution towards the development of cost effective ecofriendly structures. The failures and success stories of some of the protective
measures are discussed. Finally, a conceptual model for the protection of
BRE in the future is discussed in relation to the safety of rural agriculturalland as well as densely populated urban and industrial area keeping the goodaquatic health of the river itself.

2. HISTORY AND EVOLUTION OF PROTECTIVE MEASURES
2.1

History of BRE River Training/ Bank Protection Works

The historical perspectives of the river training/ bank protection works
have been summarized in some recent reports under Flood Action Plan
(FAP 1, 1994). Before FAP studies, a considerable amount of investment
has been made in bank protection work along BRE but the success story ofsuch protective measures are very few. Relatively successful river training
works could be found in Sirajgonj Town protection by means of a groin in
combination of earthen spurs at the downstream where randomly dumped
concrete blocks were used. The protection of Sariakandi by means ofKalitala groin is another example of partial success against river erosion.
The unplanned local disturbances created by the interventions may
extend towards the longer reaches where river need to have different set ofmorphological equilibrium (Rahman, 1998). For example, the Kalitola groindiverts flow away from BRE and creates significant changes at the local
scale as well morphological scale. It re-distributes the approach flow as wellas erosion and deposition processes. Therefore, such a single structure is notdesirable at the morphological scale of the river although it has some benefit

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at the local scale. Usually, river training creates sudden impact on rivermorphology and river need longer time scale to adjust with the changed
situation towards morphologically equilibrium (Wu et al., 2005).
2.2

Evolution Processes of BRE River Training Works

Bank erosion along the Jamuna basically means the erosion offloodplain. Usually, such floodplain erosion is severe during the postmonsoon period. When main channel travels close to the flood embankment
through erosion, damages to the BRE or failure to some part of it happens
easily. Therefore, river training works along the BRE have the primaryobjective to keep the main channel away from the BRE by stopping or
minimizing erosion.
After FAP studies, specially in FAP 1 (1994), some systematic pilot
test structures were planned to execute in the form of hard point at different
sites along the BRE as shown in Figure 1. The planned location for theconstruction of Hard points are marked as rectangular and circular symbols,
while, location of the circular symbols were implemented only. These test
structures were selected at priority sites as short term works that would
constitute principal elements of long term master plan for the stabilization of
BRE. The basis of hard point concept is not to create disturbance to thenatural flow of the river like spurs or groins, rather to stabilize the present
pattern of the river by limiting the boundaries of the local width of braid belt.
Important places on the bank line need to be protected by creating ‘Hard
points’ which are isolated bank revetment works with upstream anddownstream terminations. The function of the hard point is to limit theextent of erosion. The length and spacing of the hard point determines theextent of area protected from the erosion and thus the maximum allowableembayment that is permitted in the locations between the structures.
Repair and maintenance works are very important in the river training
works even around very expensive structures such as hard point (BWDB,1999). The local effect of the training works triggered with naturalmorphological variation such as development of meander bends associatedsand bars (Blondeaux and Seminara, 1985) generate very complex situation.
Revetments and hard points are passive river training structures while hardpoints ($21,000/m) are more than 5 times expensive as compared with theconventional revetments ($4,000/m). Therefore, hard point-like structuresare very difficult to construct under the economy of a developing nation like
Bangladesh. Impermeable groins are also very expensive, for example, reconstructed Kalitala Groin ($12700/m) having a length of 130 meter that
protects around 500 meter. Specially, when foreign funding was notavailable to construct all the planned hard point structures shown in Figure 1,
the BWDB had developed some alternative low cost approaches in order tocomplete protection of BRE. Using the field experiences of BWDB
engineers devised RCC spurs ($950/m) that is less expensive than any otheravailable approaches. The RCC spurs are normally constructed in series andprotect a distance of 2-4 times of its length. Single RCC spur is risky
because of the long protruded length of the RCC spur into the river. The site

Protective Measures of Flood Embankment Along the Jamuna River in Bangladesh

359

December 2007, Dhaka, Bangladesh

and length of the RCC spur has to select on the basis of morphologicalcondition. The main considerations of construction of the RCC spur are: (i)there must be a sand bar (char land) within 1000m from the river bank;without this char land construction of RCC spur is impossible (ii) the nearbank chute channel is closed by construction of earthen shank (iii) the RCCpart is constructed in the char land (Uddin, 2007).

Figure 1: Proposed and implemented hard points in FAP 1 (1994).
It is already proved in some developed countries that the above
conventional methods can never provide environmentally suitable solutions(Klaassen, 2002) even though these are proved to be effective against bankerosion and to some extent stream restoration (narrowing and deepening thebase-flow-channels) in smaller rivers (Shields et al., 1995). Therefore, FAP
also, dealt with the development cost-effective eco-friendly structures along
the BRE in the form of permeable groins (FAP 21, 2001).

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3. PERFORMANCE OF TRANING WORKS
The overall performance of the training works has been evaluated on thebasis of available literature (BWDB, 1999), field investigation anddiscussions with BWDB engineers, water experts and stakeholders. BRE
provides protection against flooding to the adjacent region of theBrahmaputra right bank. Around 30 training structures (Figure 2) have been
constructed along BRE mostly during the last one-decade. Due to thesestructures, erosion rate has been reduced significantly (CEGIS, 2005) thatindicates the positive role of training works for the protection of BRE. In thefollowing sub-sections, the performance of each type of structures has beenoutlined briefly.
3.1

Performance of Hard Points

Sirajgonj, Sariakandi and Mathurapara hard points were constructed in
1998. These structures experienced the biggest flood in the history of the
Jamuna in 1998. The performance of Sarikandi and Mathurapara hard points
were more or less good, but damages and failures had been encountered at
the Sirajgong hard point. Due to unfavorable bathemetric development at
the upstream of the Sirajgonj hard point, the scouring rate at the upstream
part of the structure was very quick. Although the maximum scour depth did
not exceed the design scour depth, some flow slides occurred during the fastscouring processes. It was clarified that such flow slides occurred due toexcessive mica content in the soil on which aprons were set. The apron
material could not get sufficient time for its settlement on the quickly
developed scour hole. After flood 1998, the structure was repaired andrehabilitated and in recent time it is performing well.
3.2

Performance of Groins

As an example, Kalitala groin is cited here. Kalitala Groin was reconstructed in the year 2001 in one of the main channels. The length of thegroin is 130 meter and it protects a relatively short length (500 meter) at thedownstream. Huge scour depth is developed at the nose of the structure andduring the flood season water depth becomes 55-60 meter at the nose.
BWDB local office explained that the structure is in good condition and it
requires significant amount of management and maintenance works.
3.3

Performance of RCC Spurs

During the period of 1999-2002, fifteen numbers of RCC spurs havebeen constructed at different location of BRE with variable lengths andspacing. Out of these fifteen spurs, five were damaged due to poor
construction and lack of repair and maintenance works (Uddin, 2007). After
critically examined the design and performance of spurs, the reason of suchProtective Measures of Flood Embankment Along the Jamuna River in Bangladesh

361

December 2007, Dhaka, Bangladesh

failures and some modification of the shape of the spurs have beensuggested by Uddin (2007). During field investigation in March, 2007 and
September 2007, various modes of failures and their maintenance activities
are observed. These structures are constructed on the floodplain allowing
maximum scour depth of 8 meters below the construction level. CC blocks
were damped as launching apron in order to protect the scour depth inexcess of 8 meter. As, RCC spurs are constructed on the floodplain during
the dry season, it is expected that these will divert the main channel awayfrom the BRE. It was observed during the field investigation that thestructures that are in good condition is either remaining on the floodplain or
it is experiencing the hydraulic load of some branch channels (minor).
Therefore, it cannot be confirmed yet, whether such structures can sustain
against some major channels in the Jamuna or whether it requires somestructural modifications. Some of the RCC spurs are shown in Figure 2.

Figure 2: Success (left) and failure (right) of some of the RCC spurs.
3.4

Performance of Revetments

As an example, Titporal revetment adjacent to the upstream of the
Kalitala groin was investigated. The 2 km long revetment was constructedwith a side slope in the main channel. The structure is functioning well
except some minor damages due to some local problem. Huge CC blocks
were stacked at the upstream of the revetment for emergency use.
3.5

Performance of Permeable Groins

A serious of permeable groins were constructed in the pilot project
FAP 21/22 during 1994-1995 at Gaibandha. Permeable groins are less costly
as compared with the impermeable groins and have advantages from theriver ecological view-point in many cases. Permeable groins createdsignificant positive impact accelerating siltation in between the groin fields.
But at the end of the last groin, flow hit the char land almost perpendicularly
resulting severe bank erosion over there. Usually, return current at the endof the permeable groins should not be so strong and erosion downstream ofthe structure might not happen so severely. But it is happening in reality.
May be such severe erosion downstream of the permeable groins are
resulting from the changes in river morphology, specially, development of362

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sand bars. This need detail investigation to clarify the reason and its
mitigation approaches. The shape of a permeable groin and typicalembankment failure along BRE are shown in Figure 3.

Figure 3: Permeable groin (left) and embankment failure (right) along BRE.

4. SUSTAINABLE APPROACHES AGAINST RIVER EROSION
4.1

Effect of Training Works on River Morphology

River training works have significant effect on fluvial processes of ariver due to the changes in sediment balance. Therefore, the morphologicalbehavior of an alluvial river goes under sudden modification due to theinstallation of training works. The history of the river training works forabout 300 years along the lower reaches of the Yellow River and change inits fluvial processes have been explained by Wu et al. (2005). The river
looks like a suspended one above the ground level after it is fully trained.
The connections between river and floodplain are cut while floodplains are
considered as primary source of nutrients and habitats for the riverine
ecology associated with all the plants and animals living in the riverfloodplain system.
4.2

Use of Bandalling for River Training

The conceptual approach (Rahman et al., 2003) for the use of
bandalling against river bank erosion was tested in the laboratory (Rahman
et al, 2005) and later on some recommendations are made for the necessityof pilot test in the real river (Rahman et al., 2007). Following the guidelines
from the above researches on bandal structures, River Research Institute(RRI) in its own research program has tested the applicability of bandalling
along the BRE near Sirajganj during the monsoon of 2007. Total ten
numbers of bandal structures with 12 meter length for each were constructedin series (approx. covers 700 meter) at the cost of 3000 US Dollars. The
height of the bamboo frame bandals was around 4.5 meter. During the flood
season the bandal were submerged and after monsoon flood, it was foundthat the most upstream two bandals were damaged whereas, the remaining
eight structures are working well. Huge sedimentation near the bank side
was observed. From the above field experiments and previous pilot study

Protective Measures of Flood Embankment Along the Jamuna River in Bangladesh

363

December 2007, Dhaka, Bangladesh

under FAP 21 (2001), some of the related issues on the bandal structures for
its usage as river training work are clarified. Series of bandals can makesedimentation near the bank line, but a single bandal is not effective. For ariver like the Jamuna, the choice of material for bandal structures should bemade carefully. Bamboo based material may not be effective, especially forthe most upstream structures. Moreover, bandals may not be effective as anelement of primary protection works. Rather, it may be useful as
supplementary structures in between the existing river training works. From
the recent field investigation during September 2007 (during recession
stage), it was found that severe erosion had been taken place at thedownstream of river training works along BRE including permeable groins
at Kamarjani. Sometimes, between two RCC spurs are also attacked byerosion. Such erosion at the downstream of any solid or permeable
structures is encountered due the return current developed at the nose ofeach structure as well as because of the oblique flow to the bank generated
by large scale sand bars. Return current was found to be absent in the caseof bandals (Rahman et al, 2005; 2006) as the straight flow passing below thebandal structures opposes the return current develops at the upper portion of
the bandal plate. Therefore, return currents around bandals are mutuallycounter balanced. In addition to this, due to strong lateral flow acceleration(Rahman et al., 2005), bandal creates excess flow towards the main channelaway from the bank line.
4.3

Proposed Approaches for Sustainable Erosion Management

Since the construction of BRE, several kilometers of embankment
have been retired and some of the retired sections are located about 2 km
inland from the original alignment (FAP 1, 1994). Even then, some of thereaches of BRE are very close to the main flow of the Jamuna due to erosion.
As a result of the construction of massive river training works, in general,
the amount of erosion has been reduced but frequent embankment breachingis happening each year at least one or two locations in between the training
structures or at the downstream of the structures like groins, spurs or evenhard points. Sometimes, the earthen shank of training works like RCC spurs
are also attacked by oblique flow. Construction of additional massive
training structures like revetments, groins or spurs can solve the erosion
problem to some extent, but things will be very expensive and rivers willloose its harmony with nature that is very important for riverine
environment and ecology. Moreover, oblique flow towards the bankgenerated by large-scale sand bars can hit BRE and in that cases
conventional river training works will not be effective. Bars move bothlaterally and longitudinally and direction, magnitude and location of flow
impingement to the bank will be changed each year. Recently, CEGIS(2005) introduced a bank erosion prediction tool for the Jamuna river. Suchtool is developed on the basis of dry season sedimentary features anderosion can be predicted during the next flood season. If series of bandals
are constructed in between or downstream of the existing training works
where erosion is predicted by CEGIS, then recurrent erosion problem andembankment breaching resulting can be minimized. Erosion and siltation
processes would be limited within the bandal fields and BRE will be safe at364

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ue

w

flo

w

nearly natural water and sediment flow regime. The conceptual model of the
proposed approach where major training working will be supplemented bybandals is shown in Figure 4. The flow towards bank line will be counterbalanced by the flow generated in the bandal field. Such a concept needs tobe thoroughly investigated. One of the big challenges for the bandal
structures is the choice of proper material during its construction in reality.
The nature friendly material such a bamboo, wood etc are preferable, but
considering the stability of bandals even as secondary structure in a large
scale river like the Jamuna, the construction material should be strong
enough. There is some urgent necessity of research work on the choice ofmaterial for the construction of bandal structures.

Earthen
shank
Ob

u
liq

ef

lo

w

du

c u rre n

o
et

ba

r

t

Sand bar

Return current

Embankment

Embankment

R e tu rn

Ob

liq

Ob

liq

Flow at bandal field

ue

fl o

Sand bar

nt
rre
cu
tu
rn
Re

Bandal field

Re

tu
r

nc

ur
re

nt

RCC head(a) RCC Spurs in series(b) RCC spurs in series supplemented by bandals

Figure 4: Conceptual model for bandals along BRE with RCC spurs.

5. CONCLUSIONSThe existing training works along the BRE are found to be inadequate forthe protection of Jamuna right bank. Severe erosion at the downstream ofthe existing structures as well as in between the training structures areobserved. Construction of additional conventional training structures seems
to be very expensive and is not friendly to the riverine environment.
Therefore, alternative low cost nature friendly flexible structures may
conserve the river ecology to its natural shape. The effect of a series of
bandals is recommended to investigate in between the existing structures.
Using bandals, erosion and siltation processes would be managed to adesired limit and BRE will be safe at nearly natural condition.

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REFERENCES
FAP 24, 1996. River Survey Project. Final Report- Annex 5,
Morphological Characteristics, Water Resources Planning Organization,
Ministry of Water Resources, Bangladesh.
Uddin, M. J., 2007. RCC Spur in Bangladesh: Review of Design,
Construction and Performance, Unpublished Msc Thesis, UNESCO-IHE,
The Netherlands.
FAP 1, 1994. River Training Studies of the Brahmaputra River,
Annex 3: Initial Environmental Evaluation and Annex 4: Design andConstruction, Water Resources Planning Organization, Ministry of Water
Resources, Bangladesh.
Rahman, 1998. Studies on Deformation Processes Meanderingchannels and Local Scouring around Spur-dike-like Structures,
Unpublished PhD Thesis, Kyoto University, Japan.
Wu, B., Wang, G., Ma, J. and Zhang, R., 2005. Case Study: Training
and Its Effect on Fluvial Processes in the Lower Yellow River, China,
Journal of Hydraulic Division, ASCE, Vol. 131, No. 2, 85-96.
BWDB, 1999. River bank Protection Project. Evaluation of the
Performance of Hard Points, Review of Damage during 1999 Flood Season
and Recommended Remedial Works.
Blondeaux, P. and Seminara, G., 1985. A Unified Bar-bend Theory ofRiver Meanders, Journal of Fluid Mechanics, Vol. 157, 449-470.
Rahman, M.M., Nakagawa, H., Khaleduzzaman, A.T.M. and Ishigaki,T., 2003.
Flow and scour-deposition around bandals, Proc. Fifth
International Summer Symposium, JSCE, 177-180.
Klaassen, G.J., Douben, K. and van der Waal, M., 2002. Novel
Approaches in River Engineering, River Flow 2002, 27-43.
Shields F.D. Jr., Copeland, R.R., Klingeman, P.C., Doyle, M.W. andSimon, A., 2003. Design for stream restoration, Journal of Hydraulic
Division, ASCE, Vol.129, No. 8, 575-584.
FAP 21, 2001. Guidelines and Design Manual for Standardized Bank
Protection Structures, Bank Protection Pilot Project, WARPO, Ministry of
Water Resources, Bangladesh.
CEGIS, 2005. Prediction of Bank Erosion and Morphological
Changes of the Jamuna River 2006, WARPO, Ministry of Water Resources,
Bangladesh.
Rahman, M.M., Nakagawa, H., Khaleduzzaman, ATM. and IshigakiT., 2005. Formation of navigational channel using bandal-like structures,
Annual J. of Hydraulic Engineering, JSCE, Vol. 49, 997-1002.
Rahman, M.M., Nakagawa, H., Ito, N., Haque, M. A., Islam, G. M. T.,
Rahman, M. R. and Hoque, M. M., 2006. Prediction of Local Scour Deptharound Bandal-like Structures, Annual J. of Hydraulic Engineering, JSCE,
Vol. 50, 163-168.
Rahman, M. M., Haque, M. A., Islam, G. M. T., Rahman, M. R. and
Hoque, M. M., 2007. Use of Bandals for Sediment Management,
Unpublished Report, IWFM, BUET.

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DEVELOPING A UNIVERSAL WATERRESOURCE ASSESSMENT MODEL FORSUSTAINABLE WATER SECURITYAKIYUKI KAWASAKI1) 2), SRIKANTHA HERATH1)
and KIMIRO MEGURO2)
1)
United Nations University, Japan
2)
IIS, The University of Tokyo, Japan
kawasaki@hq.unu.edu
ABSTRACT
Water is proving to be at the heart of serious environmental, politicaland economic issues around the globe. Resolving these problems requires
solutions that span across national, regional, and global scales. Recently,
the concept of "water security" has gained traction as a means for conflict
resolution, yet developing models and tools that support water security
solutions still remain to be an urgent issue.
The ultimate goal of this study is to develop Universal Water
Assessment Indicators and tools that support water-security related
problem-solving using a Spatial Information Platform for Watershed
Environmental Assessments based on ideas, concepts, and prototypes
developed in-house at laboratory. The objectives of the study are as follows:
To represent a wide range of water resource indicators in an
integrated format.
To quantify and reveal typically concealed relationships such as total
water supply and demand, and complicated links between upstream
water resources and downstream users.
To identify problem hot spots and effective solutions.
To dynamically analyze the influences of natural and anthropogenic
activity on water systems.
To investigate optimal combinations of water management and waterrights at each location for all involved in terms of sustainability andcost effectiveness.
The models and tools shall include not only factors directly related towater itself like water supply and demand, water quality and flow, access,and safety; but also indirect factors change like economic and social
systems, education for water use, ethnic issues, disaster response, andecosystem services. Currently, no integrated indicators exist that properly
capture the spatial distribution and temporal variability due to current
regulatory and spatial limitations. Developing such Universal Water
Assessment Indicators shall aid in developing concrete solutions to water
security issues on a human-scale based on a GIS database. Mekong Riverbasin was selected as a study area.

367

December 2007, Dhaka, Bangladesh

1. INTRODUCTION
During the next 50 years, population and economic growth is projected todrive up the demand for water by 30 – 85% according to the MA scenario(Millennium Ecosystem Assessment, 2005). Scenarios developed by theIntergovernmental Panel on Climate Change project an increase in global
mean surface temperature of 2.0-6.4 °Celsius above preindustrial levels by
2100, which will entail rising incidences of floods and droughts. Even now
in the 21st century however, water crises are proving to be a very serious
issue at the global level. Addressing and resolving these problems requires
developing strategies and agreements in national, regional, and global levels.
In recent years, the concept of "Water security" which seeks to resolve andavoid disputes rooted in securing water rights and water shortages, isbecoming more common, and developing models and tools that contributeto water access problem solving is an urgent issue.
A broad range of models are available for assessing a single
dimension of water related issues, but the focus is often limited to aparticular domain of the total environment. Examples include dynamic
models such as climate models, lake models, river basin models, andmeteorological models; as well as static models like economic models,scenario assessment models, and risk assessment models. As each of thesemodels is limited in scope, it is possible that some critical detail isoverlooked. Another major challenge for assessment models is theincorporation of social aspects such as individual and group behavior aswell as institutional arrangements and performance. The last few decades
have seen a dramatic improvement in various modeling aspects. On one
hand, new, advanced modeling techniques like agent-based systems andcellular automata are gaining popularity, and on the other, model input dataof ever higher temporal and spatial resolutions have become available due totechnological advancements in remote sensing and GIS applications. Suchdevelopments in modeling and data observation have made integrated
assessments more feasible goals.

2. OBJECTIVE
The ultimate goal of this study is to develop Integrated Water Assessment
Indicators and tools that support water-security related problem solving
using a Spatial Information Platform for Watershed Environmental
Assessments (Kawasaki et al., 2005)(Figure 1; Figure 2). The study aims toachieve:- Represent a wide range of water resource indicators in an integrated
manner.
- Quantitatively represent hitherto concealed relationships such as thetotal balance of water supply and demand, and complicated links
between upstream water resources and downstream water
beneficiaries.
- Answer questions like "What is the problem?", "Where does it
happen?", and "What kind of response is effective?" using a368

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panoramic view of the entire picture and making assessments of thecomprehensive situation using integrated models and tools.
- Dynamically analyze the influences of nature, human activity andsocial systems.
- Propose various scenarios in order to investigate how to deliver the
optimal (i.e. sustainable, fair and equal) combination of water
management and water rights at each location for all involved.
In essence, this study will deliver detailed models and tools for indepth spatial-temporal data via a Spatial Information Platform for
Watershed Environmental Assessments. Final results like models and tools
shall be made available on the Web to the general public in order to promoteinternational versatility, and support collaboration among stakeholders on
water security policy.

Average BOD in past 30 years
LanduseAverage BOD

Watershed area and population

Population

Figure 1: Analysis of water quality and socioeconomic statistics(Prototype of a Spatial Information Platform for Watershed
Environmental Assessments)

Figure 2: Time-series analysis among water quality, land use andpopulation (Prototype of a Spatial Information Platform for Watershed
Environmental Assessments)

Developing a Universal Water Resource Assessment Model for Sustainable Water Security369

December 2007, Dhaka, Bangladesh

3. OUTLINEThis study presents several Integrated Water Assessment Indicators toindicate sustainable water security for a variety of users (individuals, groups
and organizations). Developing water resource indicators calls for a
multidirectional and comprehensive approach, including not only factors
directly related to water itself like water supply and demand, water quality
and flow, access, and safety; but also indirect factors change like economic
and social systems, education for water use, ethnic issues (e.g. awareness ofwater saving and knowledge about water discharge), disaster vulnerability,and ecosystem services (Figure 3).

Figure 3: Flowchart for creating integrated model

4. SIGNIFICANCE
-

-

370

Currently, no integrated indicators exist that properly capture thespatial distribution and temporal variability, because current
assessments are implemented in terms of governmental boundaries
and regional-limitations. Developing these Integrated Water
Assessment Indicators allows answering the questions, "What is the
problem?", "Where does it happen?", "What kind of response iseffective?" in concrete locations at a human-scaled resolution (20mmesh) based on a detailed GIS database.
Many institutes in member countries in the Forum for GloballyIntegrated Environmental Assessment Modeling (GLEAM) hosted
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ICUS Report 27-

by the United Nations University and RIVM (National Institute for
Public Health and the Environment in the Netherlands) aredeveloping Globally-Integrated Environmental Assessment Models
for economic, ecological, and social sustainability. This research issignificant because water resource management is still not
implemented in the forum.
Developing Integrated Water Assessment Indicators would facilitate
quantitative analysis for decision making, and provide anenvironment for that allows stakeholders to use the models and toolson the web to support development of sustainable water security
policy.

5. STUDY AREA
Mekong River basin was selected as the study area in this study. MekongRiver rises in the Tibetan Plateau and empties into the South China Sea after
travelling 4,000km and flows through six countries, China, Myanmar,
Thailand, Lao PDR, Cambodia and Vietnam draining 800,000km2. This is
the largest international river in Asia. The building collaborative research
and management system for “water security” are required in urgent.
Three basins in the middle lower Mekong River, Sekong, Seasan and
Sre Pok river basins were selected as pilot area for intensive field survey,
data collection, and conducting questionnaire (Figure 4).

Figure 4: Mekong River basin and pilot study area

Developing a Universal Water Resource Assessment Model for Sustainable Water Security

371

December 2007, Dhaka, Bangladesh

6. METHOLODOGIES
6.1 Choosing and weighting indicators by literature review andinterviews with authorities
Factors contributing to disputes caused by water resource security
shall be clarified in the Mekong River, Nile River, rivers in southern Africa
and domestic rivers in Japan. Secondly, data sources available for indicatorevaluation shall be identified. Data from GIS sources, remote sensing, andsocial statistics would be used for assessing the status of naturalenvironments and human activity. As for items that are difficult to quantify
such as education, local awareness, regulations, and social systems,
assessment methodologies and weighting shall be determined byquestionnaires and interviews with authorities. Indicators that are common
among all areas or unique to an area shall be determined by comparative
review, since natural conditions, social systems, available databases,
assessment indicators, and weighting schemes vary according to region.
6.2

Framework design and data collection through investigative
surveys at foreign institutes

Theoretical frameworks, models and tools related to individual
indicators shall be surveyed in order to examine various components of theintegrated models and tools. A significant portion of this survey shall be
conducted at a leading institute for water resource management in Australia.
6.3

Developing integrated water assessment indicators

Based on information gathered during data collection and throughdiscussion with authorities, new models and tools shall be developed andthen implemented as a series of system. The following points shall drive thedevelopment process:
-

-

6.4

Variability of spatial resolution (functions shall adjust to differencesin spatial resolution, so that 1 km resolution would be enough inmountain areas, but 5 m resolution is required in urbanized areas).
Storing and analyzing functionality for time series data (e.g., Utilizing
the time series functions of the Arc Hydro data model (Maidment,
2005; Kawasaki et al., 2007))
Incorporate feedback into model and tool adjustment and revision

Models and tools shall be fine-tuned and grown based on feedback
from discussions with policy makers, citizen groups, and authorities inwater resources management. Finally, Integrated Water Assessment
Indicators and tools that can be of practical use by various stakeholders shallbe developed that single out the best forms of required data, indicators,
assessment methods, and utility system.

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7. DEVELOPING SPATIAL INFORMATION SHARING SYSTEM
ON THE MEKONG BASIN RESEARCH NETWORKAs a first step of this research, prototype system of spatial information
sharing system including GIS data, tools and models is developed on the
portal web site of MekongBasinResearchNetwork (MekongNet) operated byUnited Nations University (Figure 5). The purpose of this site is not only
enhancing research database in Mekong River basin, but also humanresearch network in the area by providing models and tools which users canuse easily such as flood simulation on the web, in addition to GIS database.
Only partial database is opened to public at this moment since the GIS
database created by other than United Nations University has limitation or
copy right for web publishing (Figure 6). ESRI ArcIMS was used to serve
GIS data on the Web. Basic data was integrated into Geodatabase format(Zeiler, 1999) and Arc Hydro will be embedded for further hydrologicalanalysis in near future.

Figure 5: MekongBasinResearchNetwork (MekongNet)

Figure 6: UNU spatial data sharing system for Mekong River basin(Prototype)

Developing a Universal Water Resource Assessment Model for Sustainable Water Security

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December 2007, Dhaka, Bangladesh

8. CONCLUSIONS
Concept, framework and methodologies of entire research were described inthis paper, as well as the introduction of collaborative portal site of
MekongNet and prototyped Web-based GIS data serving system. Promoting
this research and improving water security in Mekong River basin require
not only corporation among people among various entities across national,
regional and local inside Mekong River basin, but also it’s supporting
system by researchers, policymakers and general public from countries ofoutside the region. In this research, developing a platform for improving
water security in Mekong River basin was the first big target. To realize thisbig challenge, we are trying to prepare many places and opportunities to
conduct discussion among stakeholders by overlaying various data as GIS
layers and obtaining comments, advice, and corporations from various
stakeholders.
ACKNOWLEDGEMENT
This study was supported financially by Research Fellowships of the Japan
Society for the Promotion of Science for Young Scientists.

REFERENCES
Maidment, D.R. (2002) Arc Hydro: GIS for Water Resources. Redlands,
USA: ESRI Press.
Millennium Ecosystem Assessment (2005) Ecosystems and Hunan Wellbeing: Synthesis. Washington DC: Island Press.
Kawasaki, A., Sato, Y., Sadohara, S., 2005. Creating an Integrated Water
Geodatabase for Environmental Risk Management, Proceedings of the
Fourth Inter-national Symposium on New Technologies for Urban
Safety of Mega Cities in Asia, Singapore, 489-498.
Kawasaki, A., Yoshida, S. and Sadohara, S., 2007. Outline of water
resources GIS application, Arc hydro, and case studies in the UnitedStates, Theory and Applications of GIS, determined for publication,
Vol.15, no.1, 29-37.
Zeiler, M (1999) Modeling Our World: The ESRI Guide to Geodatabase
Design. California: ESRI Press.

374

New Technologies for Urban Safety of Mega Cities in AsiaAPPLICATION OF REMOTE SENSINGAND GIS TECHNIQUES IN WATER
INDUCED DISASTER MANAGEMENT:A CASE STUDY OF BANGLADESH
MD. SHAHABUL ISLAM(Local Government Engineering Department, Bangladesh)shahabul1@yahoo.com
MD. MAFIZUR RAHMAN(Bangladesh University Of Engineering & Technology, Bangladesh)mafiz@agni.com
MD. AYNUL KABIR(Flood Forecasting & Warning Centre, Bangladesh Water Development
Board, Bangladesh)aynulce@yahoo.com
ABSTRACT
Flooded area, flood hazard as well as flood vulnerability in the
district of Munshiganj in Bangladesh were assessed by using Remotesensing (RS) and Geographic Information System (GIS) techniques. Image
data of the peak flood date from RADARSAT for the year 2004 and ASTER
the image of October 2004 was analyzed for the extent of the flood area aswell as the land cover of the locality. Combining them with population data
a population distribution map was produced according to land use types
Conventional method of flood map by MIKE11 was also compared.
Subsequently, the outcome was compared with flooded area mapped using
satellite data in creating population that is at risk during a normal floodeven Last of all potential flood shelters in case of severe and medium floods
for mitigation measures for future planning were identified based on
information such as existing schools, administrative headquarters location,
topography and accessibility. For Digital Elevation Model (DEM), SRTM
2000 image was used. A landuse planning was also suggested in the study
area depending on the field verification by community participation as well
as GIS Techniques.
Key Words: Disaster, Flood Hazard, GIS, RS, RADARSAT, ASTER,
SRTM, DEM, MIKE11.

1. INTRODUCTION
Bangladesh is known as the ‘land of rivers’ and the major rivers are theGanges, the Brahmaputra and the Meghna with a complex network of 230
rivers including 57 internationally trans-boundary (cross boundary) rivers.
The Ganges (Padma), the Brahmaputra (Jamuna) and the Meghna are the375

December 2007, Dhaka, Bangladesh

large rivers systems in the world covering a combined total catchments areaof about 1.6 million sq km extending over Bhutan, China, India and Nepalof which only 7% falls in Bangladesh (FFWC, 2001). Munshiganj district issituated on the mixed floodplains of rivers the Ganges, the Brahmaputra,
and the Meghna. Every year even during normal rainy season floodwaterdrains through bordering rivers of the area to the Bay of Bengal. Most of thesevere floods affect the area and cause maximum damages to the lives andproperties in comparison to other areas. On the other hand, the area isdensely populated and the population is rapidly increasing raising thenumber of people at risk. The geographical position and topographic
composition have made Bangladesh vulnerable to natural disasters.
Bangladesh is frequently hit by natural disasters, most of them related towater, like flood, drought, riverbank erosion and cyclone associated storm
surge etc. Each of these has impact on the livelihood of those affected withdifferent severity. Especially floods cause immense loss to lives andproperties almost every year. In flood management, Bangladesh has
adopted many structural and non-structural measures. One of the main nonstructural measures is the flood forecasting and warning system, which is in
the process of continuous advancement. Planning for flood/erosion
management and mitigation is very important for disaster prone Bangladesh.
Remote Sensing and Geographical Information System can play a vital roleto timely and low-cost information on floods and land use status andbecome a good tool for disaster monitoring and sustainable management of
resources.
Flood is the most devastating natural phenomenon that affects anddisrupts the well being of a society, especially poor people who arevulnerable to disaster due to limitation of their resources. Most of thenatural disasters in Asia are related to flood and causing maximum damage
to lives and properties in comparison to other disasters. Bangladesh
probably is the most affected country by natural catastrophes, especially theflood.
Bangladesh experienced an unprecedented flood during July-August
2004. About one third of the country was flooded and about 30 million ofrural and urban people were directly affected. Millions were displaced fromtheir homes and lost their earning opportunities. Official number of death
was about 500 but this rose to very high level due to post flood calamities.
Road, railway and other infrastructures were destroyed.

2. OBJECTIVE
(i)
(ii)
(iii)
(iv)

376

To develop methodology for detecting flood hazard andflood vulnerability of Bangladesh.
To identify appropriate locations for flood shelters.
Land use planning specially for agriculture and fish culture.
Prepare community based flood mitigation measures andevacuation plan.

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3. DATA & SOFTWARE USED(i)

RADARSAT 23 July’04; ASTER 20 Oct’04.

(ii)

JERS SAR (Lband) Jun.’96.

(iii)

Landsat TM 17Feb.’02, SRTM 2000.

(iv)

Mike11(1- D model) flood Map for the year 2004.

(v)

Different GIS data layers.

(vi)Road database, Population, Hydro-meteorological data.

(vii)

ENVI 4.2; Arc View GIS 3.2, Arc GIS 9.0, Mike 11

4. STUDY AREA
Munshiganj district is south to the capital city Dhaka and lies approximately
between 23°22′ to 23°40′ N latitudes and 90°10′ to 90°43′ E longitudes. The
area of the district is approximately 955 sq km and is bounded by the Padma
in the south, the Meghna in the east and Buriganga and Dhaleswari in thenorth. The population of the study area is 1,289,100 according to the
population census of 2001 (BBS, 2003). The main physiographic units of
the area include the floodplains of the Padma, the Jamuna, the Meghna andthe Old Brahmaputra rivers. The agro-ecological regions include
Brahmaputra flood plain, Meghna floodplain, active Ganges floodplain,
Arial beel, old and new Brahmaputra floodplain, active Brahmaputra
floodplain, and Jamuna floodplain. Ground elevation ranges approximatelyfrom 8m above the sea level in the north to 2m in the south.

Figure 1: Location of the study Area

Application of Remote Sensing and GIS Techniques in Water Induced Disaster Management: A Case Study ofBangladesh
377

December 2007, Dhaka, Bangladesh

5. METHODOLOGY
The detail methodology is shown in flow chart below:
Flood Map
(23July 2004 MIKE11)

Flood Map
(RADARSAT, 23 July ’04)

Flood depth

Normal flood extent

Flood Hazard
Population
Land Use
Flood Vulnerability
Land cover from
ASTER 20 Oct. 2004

Field Checking of SRTM
DEM

Location of existing
Schools/Headquarters

Final
DEM

Roads
Community Survey data
Potential Shelter
Identification

Mitigation Plan

5.1

Flood Hazard Map

Flood extent was generated from RADARSAT 23 July 2004 alongwith ADEOS AVNIR and JERS SAR. Simple threshold classification
technique and visual interpretation were used in interpreting both opticaland SAR images. SAR images flooded interpretation was found the difficult
in some locations, scattering from flooded areas was comparatively low
when compared to other areas. These areas were found to have summer ricewith floodwater and the brighter area was hyacinth on the floodwater
therefore optical images and field verification had been used clarify flooded
and non-flooded areas where there was ambiguity in interpreting satellite
data. Also, the optical images helped in identifying water features that are notaffected due to rainfall. The flood extent map was converted to grid then combinedwith flood depth data generated from Mike 11 model for the same date of
RADASAT. This map was classified into 5 classes, non-flood area, low flood,378

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moderate flood, high flood and very high flood. The detail of classification andscoring are shown in Table 1.

5.2

Land use map

The vector data layers of landuse and landcover of the study area weregenerated from aerial photographs taken during 1999-2000. The land coverand the land use of the study area were found to be very heterogeneous.
Therefore, visual interpretation was done using a screen digitization
5.3

Population by Landuse Map

Upazila and union based population census data of Bangladesh
Bureau of Statistics (BBS) for the year 2001 was used for the study. Ratio of
the population for urban and rural areas for each upazila as calculated(1:6.72 for weightage). Approximated population by each land use group by
each union of that Upazila was finally calculated,then classified into 4classes; Low population, Moderate population, High population and Veryhigh population. The details of classification and scoring are shown in
Table#1.
Table 1: Scoring Rules for flood hazard classes
Maps
ClassesInterpretation
Score
No flood
1. Flood dept (m) • Non flood01• Flood dept <= 1m Low hazard
Moderatehazard2• Flood dept >1-2m
Highhazard3• Flood depth >2-3m
Very
high
hazard4• Flood depth > 3m
2. Population
Low population
1• Population(Number)<=10,000 persons
Moderate population
2• PopulationHigh
population>10,000-16,000
Very high3• Population
population>16,000-20,000
4• Population>20,000
DEM: The elevation used in Mike11 was in 300 m grid cells. Thisdata was regrouped into 3 levels; Low elevation (<3 m), Moderate (3-5 m)
and High (> 5 m). Further, this map was used to identify suitable shelter
locations.
5.4

Flood Vulnerability:

Flood vulnerability map was generated from population affected inflood hazard area by combining flood hazard map and population bylanduse map. The detail of classification and scoring are shown in Table#2
and the reclassified flood vulnerability levels are given in Table#3.

Application of Remote Sensing and GIS Techniques in Water Induced Disaster Management: A Case Study ofBangladesh
379

December 2007, Dhaka, Bangladesh

Table2: Score matrix of Flood Hazard
Flood Hazard(Depth)Population
Low (1)Low(1)Moderate
(2)

High
(3)

Very
high
(4)

2

3

4

5

Moderate (2)

3

4

5

6

High (3)

4

5

6

7

Very high (4)

5

6

7

8

5.5

Table3: Ranking Score of
Flood Vulnerability
Ranking
Score

Flood Vulnerability

2-3
4-5
6-8

Low Vulnerability
Moderate
Vulnerability
High Vulnerability

Identification of Potential Shelter Locations

One of the main objectives of the study to locate school or otherexisting structures to be used as potential shelter during severe floods. It was
assumed that a shelter should be an existing school or a hospital or agovernment office. Then, they should be located in non-flood area, in highland area and within road accessibility. In order to execute these criteria,
DEM, Roads with 500 meters buffer were used. Based on above data,
schools, hospitals, upazila and union head quarters were identified. These
identified facilities area not in flood zone and with reasonable distance toroads are considered as suitable location as shelters.
5.6

Mitigation Planning

Proposed suitable shelters and landuse planning were one of theobjectives of the study. Flood vulnerability map was overlaid with landuse
map to examine the present landuse activities and possibility of identifying
landuse practices.

6. FIELD VERIFICATION AND COMMUNITY SURVEYINGThe objectives of the field visit/survey were to: i)verify classified land use
in the study area, ii) verification of historical flood conditions through direct
dialog with the people of the locality.
6.1

Investigation of Historical Flood Conditions

Knowledge on historical flood scenarios, social-economical status,
sufferings due to the floods etc. was collected through discussions with local
communities. Information related to dissemination of flood forecasts, theneeds and benefits of the forecasts and the format of warning message
required by the local communities.
6.2

Interpretation of ASTER ImageASTER image was analyzed to identify the landuse patterns.
Landuse was classified as four different types such as agriculture, built-up

380

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area, settlement and water. The river was found to be nearer to the
Lauhajang Upazila headquarters than it was delineated during the analysis,
because of the recent river erosion at the study. The agricultural area wasfound mainly covered by potato crops. Water hyacinths were found spreadover the floodwater, making it difficult to interpret ASTER image forgeneration of flood data layer. Thus, digital classification only does not giveaccurate flood extent. Flood depth is an essential part of flood hazard
analysis and Mike 11 software was used to prepare flood depth map for the
study area.

7. RESULTS AND DISCUSSIONS(i)

Flood Vulnerability in Landuse:
From the study it shows that about 2.61% of the total area of the
district falls under high vulnerability, 45.31% under medium vulnerability,
13.96 % under low vulnerability & the rest 38.12% under no vulnerability.
(ii)

Landuse in Different Flood Vulnerability:• From the study it shows that about 2.45% of the total study area
covers a landuse of agriculture, 0.12% of the total area covers alanduse of settlement , 0.04% covers a landuse of water and almost no
area of uraban landuse is in the high vulnerable area.
• From the study it shows that about 35.57% of the total area covers alanduse of agriculture, 1.59% of the total area covers a landuse of
settlement, 7.96% area covers a landuse of water and 0.05% area ofuraban landuse is in the medium vulnerable area.
• From the study it also shows that about 6.69% of the total area covers
a landuse of agriculture, 0.50% of the total area covers a landuse of
settlement, 6.64% covers a landuse of water and 0.01% area of uraban
landuse is in the low vulnerable area.

From the study it also shows that about 26.04% of the total area
covers a landuse of agriculture, 7.53% of the total area covers a landuse of
settlement, 3.83% covers a landuse of water and 0.65% area of uraban
landuse is in the low vulnerable area.

Figure 4: Flood Vulnerability at Different Scale
Application of Remote Sensing and GIS Techniques in Water Induced Disaster Management: A Case Study ofBangladesh
381

December 2007, Dhaka, Bangladesh(iii) Shelters in the Study Area:
From the analysis it shows that 42 number of schools out of a total
1090, 2 administrative headquarters out of a total 77, 4 Growth centers outof a total of 23 of the study area can be used as shelters in case of high flood
vulnerable within the district.

Figure 5: Location of Shelters within the study area
Table4: Number of Potential Shelters within the District
Upazila_Name

Laluhajang
Munshiganj
Sadar
Gazaria
Tongibari
SrinagarSirajdikhan
Total:

No. ofSchools

NonFlooded

FloodedNo. ofSchools as
Shelter

134

67

67

4

13

8

5

0

196
143
152
264
201
1090

142
45
92
178
111
635

54
98
60
86
90
455

18
0
2
16
2
42

12
9
13
15
15
77

8
5
10
12
14
57

4
4
3
3
1
20

1
0
0
0
1
2

No. of Head NonQuarters
FloodedNo. of
HQs asFlooded Shelter

8. CONCLUSIONS AND RECOMMENDATIONSThe study clearly narrates that remote sensing and GIS can effectively be
used for flood area monitoring and identification of suitable potential
shelters during the high vulnerable floods. It is also found that RADARSAT
data in combination of Mike11 flood map can be used for flood area
mapping with mitigative measures identification. This study is therefore
suggested that an operational flood mapping system based on remotesensing and GIS techniques is very much needed in the country. This system
can be used for flood mapping, shelter location as mitigative measures aswell as for the damage assessment at the time of emergency.
Therefore the study will be useful to:(i) Develop flood area mapping in respect of different vulnerability
and land use.

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ICUS Report 27(ii)

Develop better capabilities to detect and monitor theenvironmental changes caused by flood like streamline changes,
riverbank erosion, etc.
(iii) Identify suitable flood shelters in case of severe as well as
medium floods for mitigation measures for future planning.
(iv) Develop land use planning for agriculture as well as fish
farming in the locality.
(v) If a very high resolution image is available it will be very usefulfor flood analysis in Bangladesh flood plain area
ACKNOWLEDGEMENT
The authors are grateful to Japan Aerospace Exploration Agency (JAXA)
for sponsoring the satellite data used in the study, Local Government
Engineering Department (LGED) of Bangladesh for the spatial local GIS
data and Water Development Board of Bangladesh for the Flood Model data.

REFERENCES
Bangladesh Population Census 2001, National Report (Provisional, 2003)—Bangladesh Bureau of Statistics, Planning Division, Ministry ofPlanning-p17, 30.
Flood Forecasting and Warning Centre (FFWC), 2003, Annual Flood
Report-2001, Bangladesh Water Development Board (BWDB),WAPDA Building (8th Floor), Dhaka, Bangladesh, 46pp.
Flood Forecasting and Warning Centre (FFWC), 2006, Annual Flood
Report- 2006, Bangladesh Water Development Board (BWDB).
Howlader A. H. and Islam, A.Z.M.Z, 2004, Application of Remote sensing
and GIS in Flood Mapping in Bangladesh, paper presented in the
National Workshop on Options for Flood Risk and Damage Reduction
in Bangladesh, held on 30th August 2004, Bangladesh-china
Friendship Conference Center, Dhaka, Bangladesh, 9pp.
Lal Samarakoon, Kulapamote Pathumchai and Ryuzo Yokoyama, 2004,
Land Use Planning for Flood Mitigation in Dhaka City Using Remote
Sensing and GIS, Earth Observation Research Center/Japan
Aerospace Exploration Agency (JAXA) and Asian Center for
Research on Remote Sensing, Asian Institute of Technology(AIT),ISTS-2004-n-22, p1-5.
Local Government Engineering Department (LGED), 2005, Road Inventory,
Rural Infrastructure Maintenance Management Unit, LGED.
Local Government Engineering Department (LGED), Upazila Base Map,
Geographic Information System (GIS) Unit, LGED
Nishat A., 1998, Flood Management in Bangladesh, paper presented in the
7th Regional Seminar on Earth Observation for Tropical Ecosystem
Management, held in Dhaka from 7-11 December 1998, 6p.
N. H. Akhter Hossain, 2004, An Overview on Impacts of Flood in
Bangladesh and Options for Mitigation, in Proc. of National
Application of Remote Sensing and GIS Techniques in Water Induced Disaster Management: A Case Study ofBangladesh
383

December 2007, Dhaka, Bangladesh

Workshop on "Options for Flood Risk and Damage Reduction in
Bangladesh”, 7-9 September 2004, Bangladesh-China Friendship
Conference Center, Sher-e-Bangla Nagar, Dhaka, Bangladesh, p1-22.
RADARSAT International Inc., 1996, Focus on RADARSAT, a 3-days
workshop introducing concept, operation for natural resources
analysis and environmental monitoring, held at Local Government andEngineering Department (LGED) Head Quarters, Dhaka, from 10-12
December, 1996, organized by LGED/GETCO, and sponsored by
RADARSAT International Inc

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CLIMATIC PERTURBATION AND
FLOOD RISK IN COASTAL CITIES:A COMPARATIVE STUDY IN SOUTH
AND SOUTH EAST ASIA
DUSHMANTA DUTTA
School of Applied Sciences and Engineering
Monash University, Australia
Dushmanta.dutta@sci.monash.edu.au
ABSTRACT
Approximately 20% of the global population lives within 30 km ofcoastal areas and the number is expected to become double by 2025. The
Intergovernmental Panel on Climate Change (IPCC) has predicted that the
global mean sea level (msl) may rise as much as 88 cm by the end of the
21st century. The sea level rise will have wide ranging effects on coastal
population and ecosystem, such as saline water intrusion, erosion ofshorelines, amplified intensity and frequency of coastal flood inundation, etc.
This study was an attempt to assess socio-economic impacts offlooding under climate change conditions in low-lying large coastal cities inSouth and South-east Asia, intending to raise awareness on the vulnerabilityof developing coastal cities under climate variability and socio-economicchanges towards betterment of future flood management measures. Several
large coastal cities were selected for analysis based on the socio-economic
vulnerability, frequency and duration of flooding, tidal effects on flooding,and also on the availability of data. A comprehensive methodology wasdeveloped and implemented to conduct pilot case studies in six selected
regions of six countries in South and South-east Asia. The paper presents
briefly introduces the methodology developed and the outcomes of casestudies and compares the magnitudes of socio-economic vulnerability of theselected coastal cities to extreme floods under rising sea levels.

1. INTRODUCTION
The increased concentrations of greenhouse gases in the atmospherethreaten to dramatically change the earth’s climate in the 21st Century. The
Intergovernmental Panel on Climate Change (IPCC) projects that warmingin this century could range from 1.4 to 5.8oC (IPCC, 2001). Accompanying
the warming will be substantial increases in sea level and average
precipitation and also changes in climate. Global sea level is currently rising
as a result of ocean thermal expansion and glacier melt, both caused byrecent increases in global mean temperature Nicholls, 2002; Burroughs, 2003).
With the climate already changing and further change in climate highly
likely to happen, adaptation is a necessary component of any response to
climate change. Many countries and specific sectors within these countries

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December 2007, Dhaka, Bangladesh

are vulnerable to the effects of climate change (van Dam, 2003). The IPCC
concluded that developing countries are much more vulnerable to climatechange.
Some of this vulnerability has to do with greater exposure to climatechange, e.g., having large populations in low lying coastal areas exposed tosea level rise. The coastal zone of Asia is densely populated and expected tobe home to nearly 75% of the population of the region by 2025. Many of thelarge coastal cities in Asia have already been facing severe problems due tolower elevation and their location in floodplain of major rivers. Potentially,sea level rise will have the greatest impacts in these large coastal cities. Yet,very few countries have planned the ways to deal with these problems.
This study was conducted under a collaborative research project
aimed to model the changes in flooding characteristics in several coastal
cities in South and Southeast Asia under climate change and to assess its
socio-economic impacts including vulnerability for offering a basis forformulating policies for sustainable development. The main objective of thestudy was to assess the socio-economic impacts of floods under climatechange conditions. The study scope was limited to selected low-lying large
cities of six countries of South and South-east Asia namely; Bangladesh,
India, Pakistan, Sri Lanka, Thailand and Vietnam.

2. STUDY AREAS
The selection of the coastal cities for case studies was based on the socioeconomic vulnerability, frequency and duration of flooding, tidal effects on
flooding, and also on the availability of data. Based on these criteria, thecities identified in the six countries were: Barisal and Patukhali (B-P) in
Maghna Delta (Bangladesh), Bhubaneswar, Cuttack and Puri (B-C-P) in
Lower basin (India), Karachi (Pakistan), Matara (Sri Lanka), Bangkok(Thailand), Hai Phong city (Vietnam) (Figure 1). The main factors
considered in the case studies of the coastal cities due to sea level rising indifferent periods of scenario analyses for comparative analysis were:magnitude of flood hazards, social vulnerability and risk in different sectors,
economic vulnerability and risk in different sectors and stakeholder
awareness and existing policy status. The details of these study areas
including hydrometeorological and socio-economic characteristics havebeen presented in elsewhere ((Habib-ur-Rehman et al., 2006 ; Dutta et al.,2005a; Dutta et al., 2005b ; Dutta et al., 2005c ; Bhuiyan et al., 2005 ;Swamy et al., 2005 ; Ratnayake et al., 2005).

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Puri andFigure 1: Location map of the study areas in six countries

3. METHODOLOGY
A comprehensive framework was developed to analyze the socio-economic
impacts of floods in several large coastal cities of Asia under projectedclimatic and socio-economic scenarios as shown in Figure 2. The
framework includes a more realistic and complex system of modeling thatallows incorporating anthropogenic changes together with projected climaticchanges while modeling flooding. The modeling system comprises of threecomponents: a distributed flood model, a land use change model and an
impact analysis tool.

Figure 2: Comprehensive research framework

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December 2007, Dhaka, Bangladesh

Distributed Flood Model
The distributed flood model includes two sets of models: i) a
distributed hydrological model for simulating flood inundation in areas witha converging river network and ii) a hydrodynamic modeling scheme forsimulating floods in areas with complex river networks with loops anddiverging branches. Both the models are raster based with coupled two
dimensional surface and one dimensional river network modules. The
models included the provisions of incorporating various landuse andlandcover and flood control infrastructure information at grid-scale. The
detailed descriptions of these two models have been presented in Dutta et al.
(2000) and Dutta et al. (2007), respectively.
Land use change Model
Socio-economic projections under land use change conditions arecomputed using the Antropogenically Engineered Transformations of Land
Use and Land Cover (AGENT-LUC) Model, developed by Rajan andShibasaki (2000). This is a national scale, integrated, dynamic time-series
simulation model for assessing the land use and land cover changes as resultof the human activities. It consists of four modules: the biophysical crop
yield module, the rural income module, the urban land use module and theagent decision module; and a sub-model for migration. All these modules
and the sub-model interact and have feedback loops, to determine the newcourse of action by the agent at the next time step. The model structure issequential. The biophysical crop yield model calculates the potential
productivity of the land unit for the given conditions of soil, topography,
water availability and climatic parameters. The distribution of water
availability takes into account the soil conditions, amount of rain-received,
and the existence of irrigation facilities. The main assumption of this modelis that there is a strong linkage between the climate and crop distributions(Leemans and Solomon, 1993). The crop yield estimates are derived bymodifying the approach as described in the EPIC model (Sharpley andWilliams, 1990). The central concept of this approach is the growing period
and the photosynthetic efficiency of the crops. The agent also acts as aninterface in helping to assimilate the broader macro-information into thedecision-making process at the grid level, thereby creating an action in
response to the natural and economic stimuli.’
Impact Analysis Tool
An assessment of socio-economic impact is defined here as themeasurement of the potential loss from a flood event by assessing thevulnerability of population, buildings and infrastructure to the flood hazard.
It identifies the characteristics and potential consequences of flood, howmuch of the community could be affected by it, and the impact oncommunity assets. The lack of an accepted method for carrying out
assessments that could determine the socio-economic impact of floods has
greatly limited the capacity to present a comprehensive picture in this study.
Only the highly vulnerable socio-economic categories are considered in thisstudy, which are population, buildings and transportation. Analysis isfocused on present (year 2005) and future (2050 and 2100) scenarios. A
questionnaire survey was conducted to develop a set of qualitative impact

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indices for flood impact analysis for the selected categories. Secondary data
relevant for socio-economic analysis were collected from respective
departments and then colligated with model output for present scenario
analysis. For future scenario analysis, an appropriate projection technique ofsocio-economic data was followed and then interpretation was derived inrelation with model output. Population projection techniques followed werecountry specific and were detailed under country sub-sections. Due tounavailability of data, the analysis on building category was concentrated
only on residential buildings in most of the case studies. In the case of study
areas where data pertaining to residential buildings was not available, thecount of residential buildings was extracted from population data with anapproximation of four persons dwelling per residential building.
Transportation category incorporated major road network laid within the
study area boundary.
Current assessment relies on the total number of people and buildings,
and the length of roads affected by floods due to sea level rise. The impact
indices for different categories have been computed by conducting aquestionnaire survey in six participating countries, Bangladesh, India,
Pakistan, Sri Lanka, Thailand and Vietnam. The categories considered are:residential buildings, non-residential buildings, roads, persons less than 6
years, persons between 6 to 65 years, persons above 65 years, income lessthan 100 US$, income level from US$ 100 to 400 and income level above
US$ 400. Classification criteria are also based on different impact indices.
Impact indices were prepared based on the percentage of damage. The
details of the impact indices for different depth categories are given in
Table 1.
Table 1: Impact indices for different damage category of floods
Percentage of damage Impact index
0%
No impact
0-25%
Less impact
25-50%
Moderate impact
50-75%High impact
75-100%Highest impact
For the computation of impact on people, less than 25% damage
indicates that there will be a minor health problem, if it is more than 25%
but less than 50% then there will be major problem in health, less than 75%
damage cause irretrievable illness. There will be a loss of life when thedamage exceeds 75%. To compute the flood impact on buildings, less than
25% damage means less damage to contents, structure and outside property,
then if it exceeds the range but below 50% which indicates medium damage,less than 75% damage means high damage. There will be a severe damage if
the percentage of damage is more than 75%. For roads, less than 25%
damage indicates that there will be a transportation interruption for few
hours, if it is more than 25% but less than 50% then there will be a minor
road damage, less than 75% damage cause minor road damage andtransportation interruption for few days. Severe to complete collapse of

Climatic Perturbation and Flood Risk in Coastal Cities: A Comparative Study in South and South East Asia

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December 2007, Dhaka, Bangladesh

transportation system and need for rehabilitation of major road networks areneeded when the damage exceeds 75%. Based on the depth and duration offloods and depending on the percentage of damage impact indices areprepared. A sample based on questionnaire survey results is presented inTable 2.
Table 2: Flood impact assessment for a particular category
Depth ofDuration of flood
flood (m)< 1 day
1-2 days
3-4 days
5-7 days > 1 week
0.00-0.10 No Impact No Impact No Impact No Impact No Impact
0.10-0.60
Less
Less
Less
Less
Moderate
0.60-1.00
Less
Less
Moderate Moderate Moderate
1.00-3.50 Moderate Moderate
High
High
High
> 3.50
High
High
High
High
High

4. ANALYSIS OF THE RESULTS
In this section, the results of the case studies are compared. Figure 3 shows
the comparison of the population of the six areas in the study. Population
trends show that the population increase rate will slow down with time.
Population projections reveal that the population of the Bangkok will be
doubled in 100 years time while the population in Mahanadi deltacontaining Bhuwaneswar, Cuttack and Puri (B-C-P) cities will be tripled byyear 2100. Similarly, the population of Hue city will be increased by four
folds in this century. The rate of population increase in Karachi and Matara
is lower compared to other four study areas.

Figure 3: Projected population growth in the study areas compared to
Figure 4 shows the comparison of the projected number of buildingsin six areas in the study. As no of buildings is directly related to population,
the increase in the number of buildings also follow same trend as population.
Prediction of the number of projected buildings reveals that the number ofbuildings in Bangkok city will be doubled in 100 years time while the in
Mahanadi delta containing Bhuwaneswar, Cuttack and Puri cities, thenumber of buildings will be tripled by year 2100. Similarly, number ofbuildings in Hue city will be increase by four folds in this century. And, therate of increase in number of buildings in Karachi and Matara city is lower
compared to other four study areas.

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Figure 4: Projected building growth within the study areas compared to 2005

Figure 5 presents the projected impacts of the extreme flooding on
population along with the future cases considering climate change impacts.
In present condition, there is not much impact of flooding in Mahanadi delta
area in India which includes Bhubaneswar -Cuttack - Puri cities. Similarly,
people in Karachi (Pakistan) and Matara (Sri Lanka) are also not muchaffected by present flooding condition as more than 85% population isunaffected by flooding. Almost half population of Hue city is unaffected bypresent flooding scenario where as in Barisal - Patuakhali cities in
Bangladesh, only 17% population is unaffected by flooding in the current
scenario.
Figures 6 and 7 present the present effect of the flooding on number ofbuildings and on roads (highways) along with the future cases considering
climate change impacts. In present condition, there is not much impact offlooding in Mahanadi delta area in India which includes BhubaneswarCuttack-Puri cities on buildings. Similarly, buildings in Karachi (Pakistan)and Matara (Sri Lanka) are also not much affected by present flooding
condition as more than 80% buildings are unaffected by flooding. Almost
half of total houses in Hue city is unaffected by present flooding scenario
where as in Barisal-Patuakhali cities in Bangladesh, only 17% houses areunaffected by flooding in the current scenario. In present extreme flood
scenario, roads are not affected at all.

Figure 5: Impacts of floods on population within the study areas
In case of 2050 projected scenario, there is little impact of flooding on
population in Karachi and Matara cities as almost 85% population will

Climatic Perturbation and Flood Risk in Coastal Cities: A Comparative Study in South and South East Asia

391

December 2007, Dhaka, Bangladeshremain unaffected due to projected flooding scenario of sea level rise. Incase of Mahanadi delta area in India which includes Bhubaneswar-CuttackPuri cities, three fourth of projected population will remain unaffected.
Almost half population will be affected in Bangkok and Hue city. Barisal Patuakhali cities in Bangladesh will be highly affected by projected flooding
scenario due to sea level rise but majority of impact falls in less affectedindex category. In case of buildings, the impact of projected flooding is lesssignificant for the buildings in Karachi and Matara cities as almost 85%
buildings will remain unaffected due to due to sea level rise. There is not big
impact of flooding in Mahanadi delta area in India which includes
Bhubaneswar-Cuttack-Puri cities as 75% buildings will remain unaffected.
Almost half of total projected buildings will be affected in Hue city. In caseof Barisal - Patuakhali cities in Bangladesh and Bangkok, the buildings in
the cities will be highly affected by projected flooding scenario due to sea
level rise but majority ( 75%) of impact falls in less affected index category.
There will be significant impact on road in Mahanadi delta area in India
which includes Bhubaneswar-Cuttack-Puri cities as almost 50% of the roadwill be affected by projected flooding scenario. In other cities, roads willremain almost unaffected.

Figure 6: Impacts of floods on buildings in the study areas

Figure 7: Impacts of floods on roads in the study areas
In case of 2100 projected scenario, there is little impact of flooding on
population in Karachi and Matara cities as almost 87% population willremain unaffected due to projected flooding scenario of sea level rise. Incase of Mahanadi delta area in India which includes Bhubaneswar-Cuttack Puri cities, one fourth of projected population (about 27%) will be affected392

New Technologies for Urban Safety of Mega Cities in Asia

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due to sea level rise scenario. Almost half of total projected population will
be affected in Bangkok and Hue city. Barisal-Patuakhali cities in
Bangladesh will be highly affected by projected flooding scenario due to sea
level rise and majority of impact (70%) falls in moderately affected index
category. In case of buildings, the impact of projected flooding is lesssignificant for the buildings in Karachi and Matara as almost 80% buildings
will remain unaffected due to due to sea level rise. There is not big impact
of flooding in Mahanadi delta area in India which includes Bhubaneswar Cuttack-Puri cities as 72% buildings will remain unaffected. Almost half oftotal projected buildings will be affected due to flooding in Hue city. In caseof Bangkok, the buildings in the cities will be highly affected by projectedflooding scenario due to sea level rise but majority (90%) of impact falls in
less affected index category. There will be significant impact on road in
Mahanadi delta area in India which includes Bhubaneswar-Cuttack-Puri
cities as almost 75% of the road will be affected by projected flooding
scenario. In other cities, roads will remain almost unaffected except Karachi
where there will be some impact of flooding as 25% of the roads will beaffected by projected flooding scenario due to sea level rise.
Reviewing the existing policies of different countries, it has been
observed that most of the countries have flood and disaster management
polices but they don’t touch the issue of climate change impact. For
example, in case of Thailand, the existing basin management plan, flood
management plan do not touch upon the issue of climate change impacts(Tawatchai, 2005). Similarly in case of India, the existing National Water
Policy, National Disaster Management bill, disaster risk management
program don’t mention specifically mention about climate change impact
issue (Sanyal, 2005). In Pakistan, policies like Water Policy, The Pakistan
Water Sector Strategy, Sindh Katchi Abadis (unauthorized dwelling) Act
exist but they incorporate the issue of climate change impacts. Similarly, in
the National Disaster Management Plan, Flood Protection Ordinance,
Coastal management policy, watershed management policy of Sri Lanka,
the issue of climate change impact remains untouched in these policies(Kamaladasa, 2005). The story is not different in case of Vietnam. They
have many policies related to flood management and disaster mitigation, but
the issue of climate change impacts remains unmentioned in those policies.
In case of Bangladesh, the issue of climate change impact has been touched
upon in National Water Policy, which recognizes climate change induced
flood as one of the factors determining future water supply and demand.
Similarly, National Water Management Plan (NWMP) addresses the issuesof coastal flooding due to sea level rise (Ali and Rahman, 2005; Islam,2005).

5. CONCLUSIONS
From the comparative analysis it can be concluded that the coastal cities in
Bangladesh is highly vulnerable to floods under climate change conditions
as far as the high priority category, viz. population, is concerned. For thecities Bangkok and Hue, the extent of damage imposed by climate change is

Climatic Perturbation and Flood Risk in Coastal Cities: A Comparative Study in South and South East Asia

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December 2007, Dhaka, Bangladesh

considerable, albeit lower in comparison to cities of Bangladesh. Cities
located in the Mahanadi delta of India are found to be more sensitive as far
as the damage on road network is concerned. It has to be seen whether the
existing policies in the respective countries are considering the climatechange issue to the desired level of seriousness. The study foundBangladesh to be at the safer side as far as policy is concerned. However,the policy setup of other countries is lacking any vivid section pertaining toclimate change issues, which may aggravate the future vulnerability
situation, and need to be looked upon substantially.
The major recommendation developed out of this study is the need fora single organization or agency dealing with flood mitigation and which cansimultaneously address climate change issues. The necessity for delineating
flood mitigation and management policies from disaster management policy
and the significance of incorporating climate change issues in the Coastal
Development Authority Act is also recommended.
Further research should consider development of a holistic approachin assessing impact of extreme climate events (including sea level rise) tocoastal systems including social, economic and environment aspects foradaptation strategies for integrated coastal zone management.
ACKNOWLEDGEMENT
The research was financially sponsored by the Asia Pacific Network for
Global Change Research under its CAPaBLE Programme (Grant no. 2004CB01NSY-Dutta).

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Bhuiyan, J.A.N, D. Dutta, A. Das Gupta and M.S. Babel (2005). Floodsimulation and its socio-economic impact analysis in Meghna Delta,
Bangladesh under climate change conditions, Proceedings of theInternational Symposium on Floods in Coastal Cities under Climate
Change Conditions, AIT, Thailand, June, pp. 1-10.
Burroughs (2003)(ed). Climate into the 21st Century, World MeteorologicalOrganization, Cambridge University Press, 240p.
Dutta, D., J. Alam, K. Umeda, M. Hayashi and S. Hironaka (2007). A two
dimensional hydrodynamic model for flood inundation simulation: acase study in the Lower Mekong River basin, Hydrological Processes,
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Dutta, D., S. Niu and K.S. Rajan (2005b). Modeling and socio-economic
impact analysis of floods under sea level rising scenarios in Bangkok,
Thailand, Proceedings of the International Symposium on Floods inCoastal Cities under Climate Change Conditions, AIT, Thailand,June, pp. 51-64.
Dutta, D., J. Alam and H.M. Hien (2005c). Flood simulation and its socioeconomic impact analysis under climate change condition in Hue City,
Vietnam, Proceedings of the International Symposium on Floods inCoastal Cities under Climate Change Conditions, AIT, Thailand,June, pp. 85-96.
Dutta, D., Herath, S. and Musiake, K. (2000). Flood inundation simulation
in a river basin using a physically based distributed hydrologic model.
Hydrological Processes 14: 497-519.
Habib-ur-Rehman, N.M. Khan, D. Dutta (2006). Assessment of extent offlooding under climate change condition in Coastal city of Pakistan.
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89-102. Water Resources Publications, LLC, CO, USA, ISBN #978-1887201-46-9.
IPCC. 2001. Climate Change 2001: Impacts, Adaptation and Vulnerability.
Contribution of Working Group II to the Third Assessment Report of
the Intergovernmental Panel on Climate Change (IPCC). Cambridge
University Press, Cambridge, UK
Islam RM (2005). ICZM program in Bangladesh: An overview of policy &strategy initiatives, Proceedings of the International Symposium on
Floods in Coastal Cities under Climate Change Conditions, AIT,
Thailand, pp. 107-114.
Kamaladasa N. (2005). Flood risk management policies of Sri Lanka,
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Cities under Climate Change Conditions, AIT, Thailand, pp. 131-136.
Leemans R., and Solomon, A.M. (1993). Modeling the Potential Change inYield and Distribution of the Earth’s Crops under a Warmed Climate,
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Sharpley, A.N. and Williams, J.R. (1990). EPIC – Erosion/Productivity
Impact Calculator: 1. Model Documentation, USDA Technical
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modeling during severe cyclonic storms and socio-economic analyses
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Change Conditions, AIT, Thailand, June, pp. 37-46.
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SPONTANEOUS URBANIZATION OF
DHAKA CITY AND WATER LOGGINGAS A CONSEQUENCE
UMMA TAMIMA
Lecturer, Department of Urban and Regional Planning,
BUET, Dhaka, Bangladesh.
umma_tamima@urp.buet.ac.bd
MD. SHOHEL REZA AMIN
Lecturer, Department of Urban and Regional Planning,
Jahangirnagar University, Savar, Dhaka, Bangladesh
shohelamin@gmail.com
ABSTRACTThe urban environment has distinctive biophysical features in relation
to surrounding natural and rural areas. These include an altered energy
exchange creating an urban heat island, and changes to hydrology such asincreased surface runoff of rainwater. Such changes are, in part, a result of
the altered surface cover of the urban area. For example an increase insurface sealing results in increased surface runoff. The peripheral growth,particularly to the east of the main built-up area of Dhaka City, involves arisk which many have come to accept, if not willingly, because ofdestruction of wetlands and natural cannels. The unplanned change of land
use and the encroachment of khals and lakes in the city cause a serious
affect on the storm water drainage and wetlands in the Dhaka City. This
paper focuses on the urbanization and drainage system of Dhaka City, finds
out the impact of urbanization on the existing drainage channels andwetlands and proposes some recommendations for sustainable managementof drainage system and wetlands of Dhaka City.

1. BACKGROUND OF THE STUDY
Dhaka City with its staggering population of about 12 million is recorded as
one of the most populous cities in the world. The last decadal growth rate
was about 45 percent, though the population growth rate was more than 100
percent in the previous decade (1981 to 1991). Population statistics ofDhaka City show that the annual growth rate was 2.9 percent from 1951 to
1961, 10.2 percent from 1961 to 1974, and 8.1 percent from 1974 to 1981
(Hasnat, 2006). Dealing with the huge population, the city seems to bedisintegrated and incompetent. Even though the basic services are
deteriorating to their lowest ebb, yet a substantial number of people are stillout of service (Alam, 2006). The city is not only incapable of providing
services but also expanding spontaneously by filling the adjacent low lands
or wetlands due to the growth of the city population. Consequently thechannels, wetlands and depressions, previously acted as drainage basin
holding rainwater and drain it to the river system, is obstructed resulting in a397

December 2007, Dhaka, Bangladesh

water congestion problem. A few hours of rain inundate many of the city
streets and during floods the entire low-lying areas and even the major
portion of Dhaka go under water for days. Though the Water Body
Conservation Act 2000 is for the protection of wetlands, the application is
negligible and this may lead to lose of hydrographic features of Dhaka City
with progressive urbanization.
The objectives of the study are to discuss the existing status ofurbanization and drainage system of Dhaka City, to find out the impact ofurbanization on the existing drainage channels and wetlands and to propose
some recommendations for sustainable management of drainage system andwetlands of Dhaka City.

2. URBANIZATION IN DHAKA CITY
The rate of expansion of Dhaka City in terms of area and population is thehighest among all the urban centers in Bangladesh. The population of Dhaka
City has increased about 10 fold and the area has expanded about 4 times
because the city is the hub of all economic, administrative and otheractivities (Table 1 and 2). It is projected that in the next 25 years the urban
population will increase to 60 percent and the rural population will decrease
to 40 percent. In order to accommodate the increasing population of the city,
low-lying areas, canals and lakes around and within the city are being filled
to develop new settlements. Furthermore, as the western part of the city has
been embanked to make it flood-free, many new settlements are alreadydeveloped and under construction in the low lying areas. Therefore, longterm and short term inundation in Dhaka City is a common phenomena
now-a-days (Hossain et al., 2006).
Table 1: Recent and projected expansion of Dhaka City
Area

1990
Population

Greater
4473000
Dhaka
Narayanganj 1111000
Tongi
143000Savar
366000Keraniganj
442000Total
6535000
Source: JICA study, 1991

398

Buildup
area
km2
122.1

Total
area
km2
275

45.6
10.5
41.8
22.3
243.3

100
37
243
170
826

2010
Population

8598000

Buildup
area
km2
215.3

2000 (interpolated)
Population Builduparea
km2
6531000
168.7

2558000
65800081200081300013430000

75.5
21.3
75.1
38.1
425.3

1834500
4005005890006275009982500

60.55
15.9
58.45
30.2
333.8

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ICUS Report 27

Table 2: Recent and projected expansion of Dhaka City
Area

1991

2006

Total
Population
area
km2
Greater Dhaka 4228000
125.55271.758 7350000
Narayanganj
1184000
54.374224.366 2085000
Tongi
16200014.96732.255400000Savar
32900017.283240.061 545000
Keraniganj
56900014.255
181.534 840000
Total
6472000
226.429949.974 11228000
Source: Dhaka Metropolitan Development Plan, 1995 - 2015
Population

Build-uparea km2

2000(interpolated)
Population

6106000
1724600
3048004586007316009325600

3. DRAINAGE SYSTEM OF DHAKA CITY
Greater Dhaka City area is divided into 12 drainage zones and has morethan 40 khals in Greater Dhaka City under three major khal systems:
Degun-Ibrahimpur-Kallyanpur khal system drains to Turag river;
Dhanmondi-Paribag-Gulshan-Banani-Mahakhali-Begunbari khal systemdrains to Balu river; and Segunbagicha-Gerani-Dholai khal system drains toBalu and Buriganga rivers. The Dhaka West has 13 khals having a total
length of more than 31 km while the Dhaka East has 27 khals of total lengthof about 60 km. Approximately 80% of rainwater of the city drained
through these channels (JICA, 1991).
With rapid expansion of the city, the natural drainage system wasinterfered with and in some places destroyed. In the late sixties, a Master
Plan on City Drainage and Flood Control was drawn up. Again in the earlynineties, a Master Plan was formulated under the Flood Action Plan (FAP
8A). Since a long time elapsed between the preparation of the Plan and its
implementation, the drainage scenario had changed quite significantly,
given the various changes in the topography and land use and interventions.
The natural channels and wetlands are being continuously filled up by new
settlements. During the period 1990-2000, about 268 sq. km of wetlands inand around Dhaka City were filled up.

4. FUNCTIONS OF WETLANDS AND NATURAL CHANNELS INDHAKA CITY
The wetlands are distributed in the Western (between Dhaka proper to Savar,
Tongi and Gazipur) and the Eastern (urban fringe to the Shitalakha basin in
the east) part of the city. However the proposed eastern embankment of the
Dhaka City cut up eastern part into relatively shallow part (between it andthe Dhaka proper), and a relatively deeper part (Balu-Sitalakhya basin on itseast). These wetlands have important functions on the flood control, groundwater recharge and have social and ecological values.
 Wetlands play a crucial role in mitigating floods via their natural‘sponge’ function (Potter, 1994; Zedler, 2003, IUCN, 2006). In case

Spontaneous Urbanization of Dhaka City and Water Logging as a Consequence399

December 2007, Dhaka, Bangladesh







of excessive rainfall related flood discharges, wetlands function as
natural sponges playing an important role in the detention andretention of water. They store (as a basin or depression) or delay
floodwaters, e.g. by increasing resistance to water flow (hydraulicresistance) as a result of vegetation density and morphology or byabsorbing water in soil (Baker and Eijk, 2006).
Inhabitants of the city are using at least 1.3 billion liters ofgroundwater everyday supplied by Dhaka WASA. Only about 220
million liters of surface water supply has been added recently to thecity’s daily water supply (Khan et al., 1998). Nevertheless, everincreasing coverage of ground by concrete due to urbanization,
rivers, canals, ponds and low-lying areas are lessening. Motijheel,
Paltan, Arambagh, Khilgaon are some of the worst affected areas of
the city due to permanent fall of ground water table.
Connection of low-lying areas with the Balu River allows inland
water trasport of goods and passengers. In addition, the remaining
wetlands (e.g. Turag river floodplain along Tongi-Ashulia road)around Dhaka City can provide breathing spaces for the citydwellers.
JICA (1991) in its feasibility study carried out an inventory of theecological resources of Dhaka East, DND and Narayanganj West.
The total number of identified floral species and fauna species is 112
and 177 respectively. The representative productive ecologicalelements are agricultural crops and aquaculture species. The open
water bodies of potential aquaculture during the flood season
become agricultural lands during dry season. Balu river floodplain of
Dhaka east is the predominant spawning grounds of open water
capture fishery. A total of 86 aquaculture species comprising 74 fish
species, 10 fresh water prawn species and 2 crab species are
identified along with exotic species.

5. CAUSES OF WATER LOGGING IN DHAKA CITY
Large run-off produced by monsoon shower and effect of urbanization, tidal
nature of rivers and streams around the city, land depressions at certain
urban neighborhoods and some drainage factors related to presence, upkeep
and maintenance of system, altogether lead severe drainage congestion
resulting inundation in various parts of basin areas (Bose, 2005).
The reliable experience in many countries has now led to some mainprinciples in urban drainage management, which are (Tucci, n.d.): Flood control evaluation should be done in the whole basin and not
only in specific flow sections; Urban drainage control scenarios should take into account future city
developments;
 Flood control measures should not transfer the flood impact todownstream reaches, giving priority to source control measures; The impact caused by urban surface wash-off and others related tourban drainage water quality should be reduced;

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ICUS Report 27






More emphasis should be given to non-structural measures for flood
plain control such as flood zoning, insurance and real time flood
forecasting.
Management of the control starts with the implementation of Urban
Drainage Master Plan in the municipality;
Public participation in the urban drainage management should be
increased;
The development of the urban drainage should be based on the cost
recovery investments.

The urban drainage practices in Dhaka City do not fulfill theseprinciples due to the following reasons:
5.1

Unplanned urbanization

The wetlands are filled up to meet up this excessive demand of land.
The environment of Dhaka City is being continuously endangered andthreatened by various unplanned and illegal activities of private and publicbodies. Amongst the primary causes and sources of environmental
degradation is the unplanned and unauthorized construction of building inand around the Dhaka city that often fails to consider and respect minimum
environmental standard for the dwellers and the city itself.
Landsat TM/ETM satellite images of different time periods (1989,
1999, 2003) have been used to study the trend of loss of wetland in Dhaka.
Fig. 1a, 1b, 1c, 1d, 1e and 1f show the spatial coverage of the wetland in the
Dhaka City in different period of time. It can be easily understood thegradual shrinkage of wetland over the periods.
By applying graphical extension method, it can be forecasted that by
the year 2037 all temporary wetlands of Dhaka will be disappeared if thecurrent rate of loss of wetland continues. It is alarming to find that yearlyrate of loss of wetland during 1999-2003 periods is 5.67 percent where as
during 1989-1999 period; yearly rate of loss was 1.23 percent. Despite theenactment of the Water Body Conservation Act 2000, wetlands are
disappearing everyday due to the ever-increasing housing projects (Map 2.aand 2.b).

(a)

(b)

Spontaneous Urbanization of Dhaka City and Water Logging as a Consequence

(c)

401

December 2007, Dhaka, Bangladesh

(d)

(e)

(f)

Figure 1: Dhaka in (a. Pre-Mughal period, b. British Colonial period, c.
Mughal period, d. Pakistan period, e. 1980 and f. 2000 Dhaka)
Source: Hossain et al., 2006

Increase in impervious area reduces infiltration, which in turn causes
increase in surface runoff generated by rainfall. As a result, capacity ofexisting storm drainage system becomes inadequate and overflow of drains
occurs during rainy season. The link between impervious surface coverageand floods has been established since the late 1960s (Leopold, 1968;
Seaburn, 1969). As the area of impervious surface coverage increases, there
is a corresponding decrease in infiltration and an increase in surface runoff(Dunne and Leopold, 1978; Paul and Meyer, 2001). According to Arnold
and Gibbons (1996), as the percent catchment (i.e. drainage basin)
impervious surface cover increases to 10-20%, runoff increases twofold.

(a)(b)
Figure 2: Loss of wetlands in DMDP area in 1968-2003 for housingdevelopment
Source: The Daily Star, 19th May 2006

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5.2

Impact of Dhaka Metropolitan Development Plan (DMDP)

Vast tracts of wetlands at close proximity to the central city have been
attracting private developers since the 1980s. Dhaka Metropolitan
Development Plan (DMDP) has demarcated main and sub flood flow zones
of Dhaka City and prohibited any kind of land filling activity on those areas.
DMDP has also identified possible location for retention pond areas. After
construction of the western half of the Dhaka Flood Protection Embankment,
unplanned development stretched rapidly toward the low-lying areas
violating all laws and regulations. Designated flood zones on the south andwest of Dhaka are also experiencing a similar fate. As the government hasplanned to complete the construction of the eastern half of the flood
protection embankment, private individuals and developers have purchased
most of the low-lying lands that are expected to become flood protected. It
should, however, be kept in mind that even after the completion of theEastern Embankment, 12 percent of land should be kept as retention area forstorm water storage (according to a study carried out by the JICA). It wasevident from the catastrophic floods of 1988, 1998 and 2004, that the poor
discharge capacities of the existing natural drainage channels are
responsible for long duration of floods. City dwellers have alreadyexperienced the severity of rain-induced flood even during the late monsoon
month of September in 2004. Sanitation in almost the entire city had
collapsed at that time for poor drainage system. Low-lying lands around
Dhaka in the past worked as natural retainers of storm water, and as naturaldrainage network and certainly helped to maintain balance of the ecosystem.
5.3

Causes of infrastructure development

Infrastructure development and overall change in the discharge regimeof the fluvial systems along with land filling have created stress on thesewetlands. The Uttara-Ashulia road aligned right across a wetland bound toaffect the hydrodynamic conditions of water flow in that area. This is likely
to result in higher flood level and longer stay (whatever small the period
may be) of the floodwater in the wetland upstream of the road. The sectionof the Dhaka-Aricha road between Aminbazar and Boliarpur is probably
making similar effects on the floodwater regime. The western embankmentof the Dhaka City have already shell, the total area that used to be taken up
by the floodwater. The major flood of 1988 inundated huge areas of westernand central Dhaka including, Mirpur, Shyamoli, Kajipara, Sheorapara,
Mohammadpur, etc. which is now inside the flood-protection embankment.
This embankment has already reduced the space available for water ofmajor floods by several tens of square kilometers. This must be having an
increased pressure on the floodwater flow and thus on the length of theflood period. The proposed eastern embankment of the Dhaka City is also
likely to have similar effect on the flood regime.
5.4

Encroachment of khals and lakes

Along with the rapid urbanization in the city in past years, many khals
and lakes have been subject to encroachment. A number of khals already

Spontaneous Urbanization of Dhaka City and Water Logging as a Consequence403

December 2007, Dhaka, Bangladesh

have disappeared. A study by JICA (1987) observed that many portions ofmajor drainage khals were occupied by encroachment without proper
sanction, earth filling, deposition of city garbage, and buildings and roads(JICA, 1991). The city is experiencing severe problem of rainfall flooding
for the last few years. This internal rainfall flood situation worsens whenrunoff generated from high intensity rainfall combines with high water levelin the surrounding rivers. Moderate rainfall causes serious problems forsome areas of the city such as Malibag, Mauchak, Shantinagar, Rajarbagh,
Fakirapool, Purana Paltan, Motijheel, Green Road, and Mohammadpur etc.
5.5

Blockage of storm drains

Due to mismanagement of collection and disposal of solid waste inDhaka City, substantial portion of waste finds its way into the storm
drainage system. Sediment samples collected from storm sewers showedpresence of polythene bag, plastic, cloth, rubber, metal strips, glass, paper
sticks, leaves, bones and brick and stone chips in addition to soil
(Chowdhury et al., 1998).

6. PLANNING APPROACHES
Until the 1960s, the scale of city growth was determined by technicalresources, development policies and budgeting either within the capacities
of municipalities and/or government departments. The planning was verymuch focused on landscape design or determination of land use or physicalelements. Later on, the planners attempted to carry out new planningapproaches Master Plan (1959), Strategic Planning (1979) and Dhaka
Metropolitan Development Plan (1995-2015) in order to control the
spontaneous urbanization (Alam, 2006).
On the other hand, National Environment Policy, National Land Use
Regulation also stated policies on wetlands. Water Body Conservation Act
2000 states that natural water bodies mean the places which are demarcatedin the Master Plan as river, canal (khaal), depression areas (beel), lake,
stream or wetland or places which are declared as 'flood flow zones' by the
local government notification and such places should also include the land
which retains storm water. This law prohibits any kind of development onthese areas.
Despite all these rules, regulations and policies, conversion of wetland
is continuing in a devastating manner. No attempt has yet been taken to
demarcate the boundary of the retention ponds areas and other wetlands.
The delay of completion of 'Detail Area Plan' for Dhaka is another major
issue. There are few instances where the land-filling activities wereprohibited through legal action such as Modhumoti Model Town, Uttara
Model Town in Ashulia by Jamuna Group. Bangladesh Environmental
Lawyers Association (BELA) played an important role in this respect. But
these actions are very limited in number and powerful real estate companies

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are converting hundreds of acres of wetland every year (The Daily Star,
2006).

7. RECOMMENDATIONSThe urban growth and sprawl in the fringe areas of Dhaka City has been
partly spontaneous and partly initiated by the government and civic
authorities, thus resulting in spoiling natural course of wetlands and creating
flood at depressed-land areas. Given that there are overwhelming national
requirement for new housing development, the effort should be concentrated
on ensuring the development of sustainable communities and minimize theimpact of the development on flood risk among other issues (Ogunyoye etal., 2005).
• Integration between water management, land management andspatial planning is extremely important in sustainable drainage
system. In order to strengthen the resilience capacity, it is essential
to reserve more room for the river in spatial plans, not only in orderto mitigate the present floods, but also in order to deal with theconsequences of climate change. A possible expansion of the present
wetlands by nature development and floodplain restoration(transforming former farmland into natural reserves) may enlarge theflood retention capacity and may help to reduce the effects of floods
in urbanized downstream areas.
• Sustainable drainage systems can offer opportunities to restore
wetlands and this option should be considered whenever possible.
Sustainable drainage systems (SuDS) and improved resilience ofbuildings are of particular relevance to future housing development.
SuDS is a new approach to managing rainfall that seeks to overcome
the damaging effects of conventional drainage by mimicking thenatural behavior of water. SuDS meets the three integrated
objectives of dealing with runoff by controlling flow (quantity),
preventing pollution (quality) and offering environmental benefits(amenity) in equal measure. This is called the ‘drainage triangle’ anddefines the philosophy of SuDS rather than simply describing acollection of drainage techniques (Ogunyoye et al., 2005).
• It is demonstrated that local wetlands can be very effective in urban
drainage management. At least 5% of every drainage sub-catchment
should be preserved as wetlands such that total area of wetlands
including detention reservoir at pump/sluice gate site does notexceed 12% of the catchment area. This will not be difficult sincemost of the eastern part of Dhaka City are low lying and are in fact
wetlands. This is also in line with the govt. policy to preserve
wetlands.
• Renovation of the sewage and drainage system including providing
sewer lines at un-sewered zones, increasing size of sewer conduits
wherever necessary, providing exclusive storm water drainage lines,
removing silts and trapped garbage from the conduits, increase ofpumping capacity, reclamation and desilting of the outfall channels

Spontaneous Urbanization of Dhaka City and Water Logging as a Consequence405

December 2007, Dhaka, Bangladesh

•

•

•

•

•

and canals along with preservation and increment of wetland area
can improve the drainage situation (Bose, 2005).
A regional ecology-oriented environmental plan with legal measuresfor control and prevention, resource conservation areas, disastermanagement programme, outlines of the system of governance withparticipatory process are to be prepared and implemented. Various
administrative authorities, agencies and private developers should
work in cooperation and integrity following the community’scommon goal. Proper emphasis is to be given on education, research,capacity building and participatory programmes of stakeholders andpublic for broadened awareness and practical pro-sustainable activity
in this regard (Bose, 2005).
Develop a national standards for the valuation of floodplain wetland
ecosystems that enable routine cost / benefit analyses of floodplain
development / flood defense measures to routinely take account of
wetland value.
Develop a database of wetlands that describes their distribution andpotential importance to drainage system and their vulnerability tochange.
New building to be built at such areas should have a plinth height of
not less than 1.2 m from ground level. Old buildings should have
perforation in the rooms at the ground floor so that water can bepassed off during and after inundation (Bose, 2005).
Herringbone brick laying on the earthen roads in the remote fringe
areas is natural option for absorption of some runoff, than building
road with cement-concrete, which is impermeable (Bose, 2005).

8. CONCLUSION
The overall growth of population along with rapid urbanization caused ahigh pressure on the limited land of the Dhaka City along with creation of anumber of problems in the areas of environment, housing, water supply,
drainage and sanitation. Various planning approaches were initiated indifferent time phases to overcome the problems. Unfortunately all planning
initiatives have been frustrated by a number of factors due to loomed
political instability and influence; lack of public accountability; lack ofpublic awareness; desperate land and housing development taking little bit
consent of the existing rules and regulations; and corruption in the enforcing
agencies. Furthermore, it is a public belief that once a land is developed byany chance, there will be no possibility to evict the developed land e.g.
Modhumoti Model Town. Thus a comprehensive and integrated approach isnecessary along with the above-prescribed recommendation in order topreserve local wetlands and natural channels of Dhaka City for its survival.

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REFERENCES
Alam, M. S., 2006. The implications of floods for Dhaka city planning.
Options for Flood Risk and Damage Reduction in Bangladesh, a
symposium organized in 2004.
Arnold, L.A. and Gibbons, C.J. (1996) Impervious Surface Coverage-theemergence of a key environmental indicator Journal of the American
Planning Association 62: 243-258.
Baker, C. and Eijk, P. V., 2006. Sustainable Flood Management: Obstacles,
challenges and solutions. Flood Awareness and Prevention Policy inborder areas (INTERREG IIIC Network ‘FLAPP’, Netherlands.
Bose, S., 2005. Architectural and city planning measures for flood defense.
Floods, from Defence to Management. Van Beek and Taal (eds.).
Taylor and Francis Group. London.
Chowdhury, J.U., Rahman, R., Bala, S.K. and Islam, A.K.M.S., 1998.
Impact of 1998 Flood on Dhaka City and Performance of FloodControl Works. IFCDR, BUET, Dhaka
Dunne, T. and Leopold, L. B., 1978. Water in Environmental Planning.
New York: Freeman. 818 pp.
Dhaka Metropolitan Development Plan, 1995. Volume-I, Dhaka StructurePlan, Dhaka Metropolitan Development Plan (1995-2015), Rajdhani
Unnayan Kartipakka Dhaka.
DMDP, 1997. FAP-8A and 8B, Master Plan for Greater Dhaka Protection
Project (Study in Dhaka Metropolitan Area) of Bangladesh, Flood
Action Plan.
Hasnat, M. A., 2006. Flood Disaster Management in Dhaka City. Options
for Flood Risk and Damage Reduction in Bangladesh, a symposium
organized in 2004.
Hossain, A. N. H., A., Azam, K. A., and Serajuddin, M., 2006. The impact
of floods on Dhaka City’s water supply, sanitation and drainage andmitigation options. Options for Flood Risk and Damage Reduction in
Bangladesh, a symposium organized in 2004.
IUCN, 2006. www.iucn.org./en/news/archive/2006/02/02
Japan International Cooperation Agency, 1990. Updating Study on Storm
Water Drainage System Improvement Project in Dhaka City,
Supporting Report, Dhaka WASA, Dhaka.
Japan International Cooperation Agency, 1991. Master Plan for Greater
Dhaka Flood Protection Project, FAP 8A, Report I and II, Flood Plan
Coordination Organization (presently WARPO), Dhaka.
Khan, M. U., Chowdhury, J. U. and Hossain, M. S. A., 1998. Measurement
and Analysis of Rainfall-Runoff in Selected Catchments of Dhaka City.
Vol. 1: Main Report, IFCDR, BUET, Dhaka.
Leopold, L.B., 1968. Hydrology for Urban Planning- a guidebook on thehydrologic effects of urban land use USGS Circular 554, 18 pp.
Ogunyoye, F. O., Breay, R., Gunasekara, R. T., and Vigor, M., 2005.
Managing flood risk at source – showcasing best practice. Floods,
from Defence to Management. Van Beek and Taal (eds.). Taylor andFrancis Group. London.
Paul and Meyer, 2001. Streams in the Urban Landscape. Annual Review of
Ecological Systems 32:333-365.

Spontaneous Urbanization of Dhaka City and Water Logging as a Consequence407

December 2007, Dhaka, Bangladesh

Potter, K.W., 1994. Estimating potential reduction flood benefits of restored
wetlands. Water Resources Update 97: 34-38.
Seaburn, G.E., 1969. Effects of Urban Development on Direct Runoff toEast Meadow Brook, Nassau County, Long Island, New York. USGS
Professional Paper 627-B, 14 pp.
The Daily Star. 19th May 2006.
Tucci, C. E. M., n.d. Flood Control and Urban Drainage Management.
Institute of Hydraulic Research, Federal University of Rio Grande doSul, Porto Alegre, RS Brazil
Zedler, J., 2003. Wetlands at your service: reducing impacts of agriculture at
the watershed scale. Frontiers in Ecology, vol. I (2): 65-72.

408

New Technologies for Urban Safety of Mega Cities in Asia

STUDY ON THE POTENTIAL OF TREESHAPE CLASSIFICATION BY USINGTHE SIMULATED LIDAR DATA AND
A TREE CROWN MODEL
TAKAHIRO ENDO and YOSHIFUMI YASUOKAInternational Center for Urban Safety, Institute of Industrial Science,
The University of Tokyo, JAPANtendo@iis.u-tokyo.ac.jp
ABSTRACTLight Detecting and Range (LiDAR) is one of aerial remote sensing
techniques, which can acquire three-dimensional information above theground. LiDAR measurement is not only applied to investigation of 3D city
information and disaster, but also is widely applied to forestry management.
In latest forest management application of LiDAR, individual tree positionand height can be estimated by LiDAR data. However, in case ofheterogeneous forest site, in addition to the LiDAR data, visible orhyperspectral data is needed for classification of species. There has been no
study to classify species only with LiDAR data. LiDAR data with high pulse
density which is able to reconstruct tree form by point clouds have potential
to classify difference species. As an initial study, we examined possibility ofclassifying trees by simulated LiDAR data. Firstly, LiDAR data with specificpulse density was simulated by simulated 3-D tree polygons and ray tracing
technique. Secondly, the developed 3-D crown surface model, which canreconstruct canopy form, was applied to the simulated LiDAR data andparameters of the model for fitting were estimated. As the result ofanalyzing parameters, Ginkgo biloba, Zelkova serrata and Cryotomeria
jaoanica, which are main species of urban trees in Tokyo could be classified
based on properties of crown form. This result indicates that LiDAR datawith high pulse density has potential for classifying species without using
other optical sensors, which can significantly reduce measurement cost.

1. INTRODUCTION
Recently, LiDAR which is one of advanced remote sensing technologies is
becoming useful instrument for measuring 3-D information in urban area orforest area (HYYPPÄ et al.; 2001; PERSSON et al.; 2002, YU et al.; 2004,
HIRATA; 2007). The data is the LiDAR pulse returned from the target
above the ground after being emitted from an airborne devise. The data can
not only measure the ground level (digital elevation model, DEM), but also
can reconstruct the form of target.
In conventional forest management, it is difficult to measure treeheight, breast height (DBH) and position in thick forest like jungle, sinceprevious methods are carried out by using only manpower. Moreover, these409

December 2007, Dhaka, Bangladesh

methods have low efficiency, costly and time-consuming. LiDAR has thepotential in solving these problems, and many researchers have been using
to estimate growth parameters, such as height, DBH and position. The
parameters which are related to plant growth can be estimated using LiDAR
data, in case of a individual tree. However, it is difficult to estimate growthparameters in mixed forest using LiDAR, because of complex crownstructure. Hence, classification method or identification method of a tree isthe most important point before estimation of parameters using LiDAR data.
One of approaches is to use visible or hyperspectral data for classification.
But, in case of using other data with LiDAR data, the cost becomes high.
Moreover, it is difficult to measure same area on same day and time bydifference sensors. Since LiDAR data contains 3-D information of tree
crown, it is possible to reconstruct a tree crown. If classifying species fromthe crown alone would reduce cost of measurement and it would also
provide variable information on whole leaf area and current growth activity.
However, there hardly exist studies concerning tree classification methods
by LiDAR point clouds alone, as the relationship between LiDAR point
clouds and a form of tree crown is not clear. There are two reasons for thissituation. One reason is that, there are many forms of crown shapes. Crown
form depends on species, age of stand, and growing environment. (Theother reason is specification of measurement which is platform type, pulse
rate, emitting direction and so on, which is changed by each measurement.)
This initial study aims, firstly to develop a LiDAR data simulation
system and, secondly to develop an algorism for classification of species
based on LiDAR point clouds.

2. MATERIALS AND METHODS
2.1

LiDAR data simulation system

A LiDAR simulation system using 3-D tree polygon was developed inorder to simulate LiDAR data of tree crown. The tree polygon is simulatedby 3dsmax (Autodesk, USA) and the natFX (Bionatics, USA) which arekind of growth simulation software. The advantage of using these softwares
is that they can create an object with absolute coordinate system value
which can be handled in 3DCG software, and so the 3-D model can be
simulated for various situations. With regard to the simulated form of
polygon, its crown form and foliages are similar with an actual tree. In
addition, the system can modify the tree with a standard form to a tree witha smaller crown size and higher height which normally exists in highdensity forest.
LiDAR data of crown is simulated by the tree polygon and thedeveloped original program that can control spatial resolution of pulse anddirection of emitting. LiDAR data is defined as an intersection of point
between the tree surface and ray by the ray-tracing calculation technique.

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ICUS Report xx 27

In this study, we selected three species; Ginkgo biloba, Zelkova
serrata, and Cryotomeria jaoanica. There were two criteria for selection.
One is crown form, the other is branch and leaf form. Forms of both the
Ginkgo and the Cryotomeria are conical. On the other hand, form of
Zelkova is bowl-shaped. Leaf types of the Ginkgo and the Zelkova are broad.
Leaf type of the Cryotomeria is needle. With regard to configuration of
measurement, the pulse density and the emitting direction were 10 points/m2
and vertical, respectively. Five tree polygons for each species were
simulated in order to average individual variations.
2.2

Concept of the developed classification method

Classification method in this study consisted of two steps. The firststep was using properties of macroscopic form that were crown height (ch),crown radius (cr), ch/cr ratio and crown cover. The second step was using
properties of microscopic form that was the standard deviation value (S.D.).
Even if trees were similar ch/cr value, their S.D. value might be different. In
this case, S.D. value would be able to classify them, and became indicator
for classification. Actually, property of LiDAR’s point clouds between
needle leaf and broad leaf is quite different.
2.3

Approximate model of 3-D crown form

One of approximate model for tree form is an ellipsoid model reported
by Sheng et al.[2001]. This model is suitable for coniferous form, but
approximate accuracy is low around edge of bowl-shaped crown form likethe Zelkova. Crown curvature is controlled by cc parameter in the originalmodel. We introduced cc of the cosine type and the gaussian type in order toimprove accuracy of model fitting. The Sheng’s model with the original cc
type, the cosine type and the gaussian type are shown in equation 1, 2 and 3.
Parameter a, b are correction coefficient and flat rate of the cosine andgaussian faction, respectively.
The Sheng’s original model:cc(Z + ch − Zt ) cc (( X − Xt ) 2 + (Y − Yt) 2 ) 2
+
=1
ch cc
cr cc

(1)

The original type:
ccoriginal = Constant
The cosine type:1

d = (( Xt − X ) 2 + (Yt − Y ) 2 ) 2
dπ 2
cccos = b cos(
) +a
2cr

(2)

The gaussinan type\:

Study on the Potential of Tree Shape Classification by using the Simulated Lidar Data and
A Tree Crown Model

411

December 2007, Dhaka, Bangladesh12d = (( Xt − X ) + (Yt − Y ) )d
cc gaussian = b exp[− ( ) 2 ] + a
cr
2

2

(3)

Where crown height is ch, crown radius is cr, crown curvature is cc, treetop
coordinates is Xt, Yt, and Zt, d is distance on X-Y plane between the tree tip
and the specific X, Y position, a is correction coefficient and b is flat rate.
Accuracy of model fitting was verified by the S.D. value between thesimulated LiDAR data and the model. The properties of macroscopic form
and the microscopic form were calculated from the result of the model
fitting.

3. RESULTS AND DISCUSSIONS
3.1

Overview of LiDAR data simulation system

The developed system can change various pulse densities and theangles of emitting laser from anywhere, and can simulate various LiDAR
data of crown form. Figure 1 shows the simulated tree polygon (Ginkgo
biloba) as one of results. The left-hand side figure is macroscopic overview
of the form. The right-hand side figure is microscopic overview of branches
and leaves. Figure 2 stands for the simulated LiDAR data of Ginkgo biloba
as one of results. Left-hand side scatter plot is the result that carried out thesimulation with 90 degree of emitting angle. Right-hand side scatter plot is
the result with 30 degrees of emitting angle.
The result indicates that our system could simulate the LiDAR data of
the crown which was similar to that of actual tree. In order to estimate
crown cover, the best emitting angle was perpendicular. In addition, righthand side scatter plot indicates that position of stem and top may bemeasured since a stem of tree is hit by laser. In order to estimate a stem
position, the best emitting angle may be the other angles than perpendicular.

a) The macroscopic overviewb) The microscopic overview
Figure 1: The simulated thee polygon of Ginkgo biloba; a) the macroscopic
overview of the tree form (left), b) the microscopic overview of branches
and leaves (right)

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ICUS Report xx 27a) The emitting angle is 90 degreeb) The emitting angle is 30 degree
Figure 2: The simulated LiDAR data of Ginkgo biloba; the emitting angle is
90 degree (left) and 30 degree (right)
3.2

Approximation accuracy of the 3-D crown form model

The simulated LiDAR data was approximated by three models whichare 1) the Sheng’s original type, 2) the cosine type and 3) the gaussian type.
One of correlation diagrams between the Z value estimated by the 3-D
approximation model and the Z value simulated by the system is shown as
figure 3. Approximation accuracies by the cosine and gaussian type were
improved in comparison with the original type. The modified models could
not only apply to a conical form like the Ginkgo, but also apply to bowlshaped form like the Zelkova. One of results of the Zelkova is shown as theapproximated 3-D crown surfaces in figure 4. Table 1 shows the result of
approximation accuracy. These values were calculated from average of 5
samples.

a) The original typeb) The cosine typec) The Gaussian typeFigure 3: The correlation diagram between the Z value estimated by the 3D approximate model and the Z value simulated by the system; a) theoriginal type, b) the cosine type and c) the Gaussian type
Study on the Potential of Tree Shape Classification by using the Simulated Lidar Data and
A Tree Crown Model

413

December 2007, Dhaka, Bangladesha) The original typeb) The cosine typec) The gaussian typeFigure 4: The approximated 3-D crown surfaces using the best S.D. valueof the Zelkoba
Table 1: The approximate accuracy of the macroscopic and the microscopic
properties.
S.D. (m)ch/crROriginal
CosineGaussian
type
type
type
0.788
0.755
0.751
Zelkova (ave.)
0.697
0.782
0.796
0.798
1.876
1.309
1.313
Gingko (ave.)
1.959
0.823
0.812
0.812
2.424
2.093
2.099
Cryptomeria (ave.) 2.433
0.900
0.898
0.895
3.3

The probability of tree classification based on tree form

As the results of the first screening of the macroscopic property, thech/cr value of the Zelkoba, the Ginkgo, and the Cryotomeria were 0.697,
1.959, and 2.433 in Table 1, respectively. Hence, the result indicates thatspecies could be classified by only ch/cr value. Moreover, as the results ofthe second screening as the microscopic property, the S.D. value by thecosine type of the Zelkoba, the Ginkgo, and the Cryotomeria were 0.755,
1.309, and 2.093 (m), respectively. Also, the S.D. values by the gaussian
type of the Zelkoba, the Ginkgo, and the Cryotomeria were 0.751, 1.313,
and 2.099 (m), respectively. The S.D. values between the Gingko and the
Cryotomeria were different by about 70cm in spite of similar conical form.

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Therefore, this result indicates that species with the similar crown form
could be classified.

4. CONCLUSIONSThe LiDAR data simulation system was developed, and the probability ofclassification of trees based on the crown properties was investigated in thisstudy. An advantage of the simulation system is that, it can simulate point
clouds of a tree crown under different conditions such as species, various
crown forms, specific pulses density and the direction of emitting laser.
Moreover, the simulated LiDAR data was almost same as actual
measurement data. The system can help to analyze optimal measurement
condition and to develop new algorism for extraction of unknown growthparameters before an actual LiDAR measurement.
In addition, the approximate surface model of 3-D crown form wasinvestigated in order to classify tree species based on the crown property.
Two models with the cosine type and the gaussian type function as crowncurvatures have improved approximate accuracy of both conical and bowlshaped crown forms when compared with the Sheng’s model. Therefore,
these models can be used for approximate definition of crown form.
The result of having analyzed the possibility of the classification oftrees of a characteristic crown form, the macroscopic property such as the
ch/cr value can not only classify species, but also the microscopic property
such as the S.D. value can classify species with similar crown form.
The result of this study indicates that the approximated surface model
derived from point clouds have the macroscopic and the microscopic
properties that has the potential to classify species with LiDAR data alone
without using optical imaging ot other data. This will reduce cost andincrease efficiency of measurement.

REFERENCESHIRATA, Y., 2007. Forest measurement with airborne laser scannerand its trend, Jpn. J. For. Plann. 41, 1, 1-12.
HYYPPÄ, J., KELLE, O., LEHIKOINEN, M. and INKINEN, M.,
2001. A Segmentation-based method to retrieve stem volume estimationfrom 3-d tree height models produced by laser scanners, IEEE Trans. Geosci.
& Remote Sens. 39, 969-975.
SHENG, Y., GONG, p. and BLGING, G.S., 2001. Model-based
conifer-crown surface reconstruction from high-resolution aerial images.
Photogrammetric Engineering & Remote Sensing. 67,8, 957-965.
YU, X., HYYPPÄ, J., KAARTINEN, H. And MALTAMO, M, 2004.
Automatic detection of harvested trees and determination of forest growthusing airborne laser scanning. Remote Sens. Environ. 90, 451-462.72.

Study on the Potential of Tree Shape Classification by using the Simulated Lidar Data and
A Tree Crown Model

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LIDAR: A TECHNOLOGY OF NEW ERA
MOHAMMAD ABDUL QUADER
Senior GIS analyst,
Golden Hervest Scankort GIS Ltd., Dhaka, Bangladesh
quader_000@yahoo.com
MD. ZAHID HASAN SIDDIQUEE
Research Assistant, Dept. of Civil Engineering, BUETRUBEL DAS
Research Assistant, Dept. of Civil Engineering, BUETABSTRACTThe developed world is moving into a new era of using technology tomanage infrastructure using accurate land information displayed in three
dimensions: x and y represent horizontal coordinates and z represents
elevation. Improvements in gathering and displaying elevation data make it
economically feasible to gather vast quantity of data in a short period oftime and have it readily available for distribution to multiple users. Lightdetection and ranging (LIDAR) has proven a mature technology to acquire
three-dimensional point clouds for describing earth surface. So this is hightime for third world countries like Bangladesh to use this technology which
has application in geography, geology, geomorphology, seismology, remotesensing, atmospheric physics, and hydrology. Flood visits Bangladesh
almost every year. Most data collection on flood is done by traditional
methods which is extremely expensive and comparatively slow. LIDAR data,with high resolution and accuracy are suitable for improving theperformance of flood models by providing more reliable initial boundary
condition. Accurate and comprehensive high-resolution terrain data helps
greatly in planning, design, construction and maintenance of transportation
infrastructure. Improvement of drainage system, land division, utilities andthe availability of soils mapping also depends on the availability of DEM(Digital Elevation Model) which is obtained from LIDAR technology.
LIDAR may also be used to measure the speed of atmospheric winds,
densities of certain constituents of urban atmosphere. LIDAR has a notableapplication in hydrology to quantify stream channel cross sections androughness, to estimate bank erosion. LIDAR data are essential to analyze
and assess the vulnerabilities of critical infrastructure for security andnatural disaster mitigation.

1. INTRODUCTION
LIDAR (Light Detection and Ranging) is an optical remote sensing
technology that measures properties of scattered light to find range and/or
other information of a distant target.

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The prevalent method to determine distance to an object or surface isto use laser pulses. Like the similar radar technology, which uses radio
waves instead of light, the range to an object is determined by measuring thetime delay between transmission of a pulse and detection of the reflectedsignal. LIDAR technology has application in geography, geology,
geomorphology, seismology, remote sensing and atmospheric physics.
The primary difference between LIDAR and radar is that with
LIDAR, much shorter wavelengths of the electromagnetic spectrum areused, typically in the ultraviolet, visible, or near infrared. In general it ispossible to image a feature or object only about the same size as the
wavelength, or larger. Thus LIDAR is highly sensitive to aerosols and cloudparticles and has many applications in atmospheric research andmeteorology.

2. COMPONENT OF LIDAR SYSTEM
In general there are two types of LIDAR systems: micropulse LIDAR
systems and high energy systems. Micropulse systems have developed as aresult of the ever increasing amount of computer power available combinedwith advances in laser technology. They use considerably less energy in thelaser, typically on the order of one microjoules, and are often "eye-safe"
meaning they can be used without safety precautions. High-power systems
are common in atmospheric research, where they are widely used formeasuring many atmospheric parameters: the height, layering and densities
of clouds, cloud particle properties (extinction coefficient, backscatter
coefficient, depolarization), temperature, pressure, wind, humidity, trace gas
concentration (ozone, methane, nitrous oxide, etc.).

Figure 1: LIDAR uses lasers to emit light pulses that strike the ground andreflect back to the airborne sensor.

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There are several major components to a LIDAR system:
2.1

Laser

600-1000 nm lasers are most common for non-scientific applications.
They are inexpensive but since they can be focused and easily absorbed by
the eye the maximum power is limited by the need to make them eye-safe.
Eye-safety is often a requirement for most applications. A common
alternative 1550 nm lasers are eye-safe at much higher power levels since
this wavelength is not focused by the eye, but the detector technology is lessadvanced and so these wavelengths are generally used at longer ranges andlower accuracies. They are also used for military applications as 1550nm is
not visible in night vision goggles unlike the shorter 1000nm infrared laser.
Airborne topographic mapping LIDARs generally use 1064 nm diodepumped YAG lasers, while bathymetric systems generally use 532 nm
frequency doubled diode pumped YAG lasers because 532 nm penetrates
water with much less attenuation than does 1064 nm. Laser settings include
the laser repetition rate (which controls the data collection speed). Pulse
length is generally an attribute of the laser cavity length, the number ofpasses required through the gain material (YAG, YLF, etc.), and Q-switch
speed. Better target resolution is achieved with shorter pulses, provided the
LIDAR receiver detectors and electronics have sufficient bandwidth.
2.2

Scanner and optics

How fast images can be developed is also affected by the speed atwhich it can be scanned into the system. There are several options to scan
the azimuth and elevation, including dual oscillating plane mirrors, acombination with a polygon mirror, a dual axis scanner. Optic choices affectthe angular resolution and range that can be detected. A hole mirror or abeam splitter are options to collect a return signal.
2.3

Receiver and receiver electronics

Receivers are made out of several materials. Two common types are
Si and InGaAs. They are made in either PIN diode or Avalanche photodiodeconfigurations. The sensitivity of the receiver is another parameter that has
to be balanced in a LIDAR design.
2.4

Position and navigation systems

LIDAR sensors that are mounted on mobile platforms such as
airplanes or satellites require instrumentation to determine the absolute
position and orientation of the sensor. Such devices generally include a
Global Positioning System receiver and an Inertial Measurement Unit
(IMU).

Lidar: A Technology of New Era

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December 2007, Dhaka, Bangladesh

3. ADVANTAGES OF LIDAR
3.1

Accuracy

An accuracy of order of 10 - 15 cm in the vertical and 50 - 100 cm inthe horizontal is claimed by manufactures and has been demonstrated bymany field studies.
3.2

Time of data acquisition and processing:The data capture and processing time is significantly less for LIDAR
compared to other techniques. LIDAR can allow surveying rates of up to 90
km2 per hour (Environment Agency, 1997) with post-processing times of
two to three hours for every hour of recorded flight data.
3.3

Minimum user interference

User interference is minimum, as most of the data capture andprocessing steps are automatic except the maintenance of the ground GPS
station.
3.4

Weather independence

LIDAR is an active sensor and can collect data at night and can be
operated in slightly bad weather and low sun angle conditions, which
prohibit the aerial photography.
3.5

Additional data

Besides relief information, laser reflectance may be used to generateintensity images to help in classifying the terrain features. Further, thesystems can have fluorosensors allowing pollutant identification andchlorophyll mapping (Environment Agency, 1997).
3.6 Canopy penetration
Unlike photogrammetry, LIDAR can see below canopy in forested
areas and provide topographic measurements of the surface underneath.
Additionally, LIDAR generates multiple returns from single pulse travel,thus providing information about understory.
3.7

Data density

LIDAR has the ability of measuring subtle changes in terrain as it
generates a very high data density (due to firing of 2000 - 80000 pulses per
second).

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3.8

Ground control point independence

Each LIDAR pulse is individually georeferenced using the onboard
GPS, INS, and laser measurements. Only one or two GPS ground stations
are required for improving the GPS accuracy by the differential method.
Independence from GCPs makes it an ideal method for inaccessible orfeatureless areas like wastelands, ice sheets, deserts, forests, and tidal flats.
3.9

Digital compatibility

Data produced from LIDAR flights are in digital format with Easting,Northing, and Altitude values of each laser target. This makes importing ofdata to GIS and other image processing packages straightforward.
3.10 Cost
One of the major hindrances in the use of LIDAR had been the cost of
the equipment. However, in recent years the purchase price of these
instruments has been reduced so that cost is no longer a barrier to companies
capable of investing in standard aerial photogrammetry equipment.
Furthermore, with more and more users opting for LIDAR the cost of thesystem and operation is likely to go further down. Mason et al. (1999), on
the basis of overall performance evaluation of available topographic
techniques for coastal terrain, found that LIDAR could achieve good
performance at a lower cost.

4.

LIDAR APPLICATIONS

4.1

FloodsHigh-resolution and accurate LIDAR data are suitable for improving
the performance of flood models by providing a more reliable initialboundary condition. LIDAR data having multiple returns help in generating
and understanding the 3D structure of obstructions (i.e. surface roughness,
vegetation, buildings, and other structures). This information can yield thefriction coefficient over the various parts of a floodplain. LIDAR data arealso being employed for flood hazard zoning. Flood visits Bangladesh
almost every year. Bangladesh was affected by severe floods in 1988, in
1998 and also this year. According to Care, one of the world’s largest
private humanitarian organizations, 35 million people in South Asia havebeen affected by flood this year. The following table shows the loss due tofloods in Bangladesh.

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December 2007, Dhaka, Bangladesh

Table 1: Loss due to flood in Bangladesh
Year
Type
1987

1988

1998

2004

1657

1517

<1000

500

Livestock

350000

26564

15143

Roads

3000 km

Embankments

35 km

4500 km2500 km

Crops damages

1.21 m.h36727 m. Tk

2.14 m.
ha
35462
m.Tk

1.74 m. ha
37661 m. Tk.85 m. ha
31839 m. Tk

Monetaryloss (USD)

1000 m.

1200 m.

2800 m.

Human loss

16000 km45528 km3.10 m.

Source: Hossain A.,N.,H.,A., 2006

So Using LIDAR technology to prepare flood plain maps will help thegovernment and international community immensely in decision making
and assess the loss.
4.2

Coastal applications

LIDAR has generated considerable interest among coastal researchers
as a topographic tool. Highly accurate, dense, and rapidly obtained data sets
are most suitable for coastal applications like sediment transport, coastal
erosion, and coastal flood models.

Figure 2: LIDAR data of a coastal area (showing TIN and elevation )422

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ICUS Report 27

4.3

Bathymetry

LIDAR in its bathymetric form can map the bed topography up to adepth of 70 m. This information is useful for determining the siltation on
navigation canals and ports and planning the construction details.
4.4

Hydrology

LIDAR data can be used to quantify gully and stream channel crosssections and roughness, gully and stream bank erosion and channel
degradation, to estimate soil loss from gully or channel banks and tomeasure channel and flood plain roughness and cross sections for estimating
flow rates. Further, coastal channels which are difficult to map otherwise
can be automatically quantified using LIDAR data.
4.5

Landslides

LIDAR has made it possible to monitor and predict slope failure by
rapidly obtaining highly accurate and dense elevation data. In post-slideconditions rapid damage assessment and mapping can be realized using
LIDAR.
4.6

Forest Mapping

The unique feature of LIDAR of producing multiple returns from thecanopy top, under story, and the ground has attracted many to use it for
estimating forest biomass, timber volume, and other parameters.

Figure 3: LIDAR data of a forest area in Norway (showing TIN view andcross section of the area)

5. CONCLUSION
LIDAR data helps to reduce data collection costs which are the main
obstacle in planning and development especially in third world country.

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December 2007, Dhaka, Bangladesh

Some disaster occurs almost every year in the country which is densely
populated as well as poor. Determining the losses due to flood,
identifying the earthquake prone area, landslide prone area, tsunami
exposed area can be easily done if the LIDAR data are available. So
disaster prone countries can save the human resource as well as thenatural resources by using LIDAR technology in their national planning.

REFERANCES
Franz, R., Trinder, J., Clode, S. and Kubik, K. 2003. Building detection
using LIDAR data and multi-spectral images, Proceedings of VIIthdigital image computing: techniques and applications. Sun, C., Talbot,
H., Ourselin, S. and Adriaansen, T. (editors), Sydney, 10-12
December 2003.
Hossain,A.,N.,H.,A and Siddique,K.,U. 2006. Options for Flood Risk andDamage Reduction in Bangladesh. The University Press Ltd.,
Bangladesh.
Haala, N. and Brenner, C. 1999. Extraction of buildings and trees in urban
Environment. ISPRS Journal of Photogrammetry and Remote sensing, Vol.
54, pp. 130-137.
Pohl, C. and Genderen, J.L. 1998. Multisensor image fusion in remotesensing: concepts, methods and application. International Journal of
Remote sensing, Vol. 19, No. 5, pp. 823-854.
Sandia National Laboratories 2004. Synthetic Aperture Radar .[Online],
Available: http://www.sandia.gov/RADAR/whatis.html.
Thuy, T. and Tokunaga, M. 2001. Wavelet and scale-space theory insegmentation of airborne laser scanner data. Proceedings of 22nd
Asian Conferecnce on remote sensing, Singapore, 5-9 November 2001.
TopScan 2004. http://www.topscan.de/en/literatur/index.html [Online]

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MANAGEMENT OF BUILDING ENERGYCONSUMPTION AND RENEWABLE
ENERGY SUPPLY IN THE ECOLOGICALCOMMUNITIES USING GIS
MD. ZAHID HASAN SIDDIQUEE
Research Assistant, Dept. of Civil Engineering, BUET
zh027@yahoo.com
DR. URSULA EICKER
Professor, Stuttgart University of Applied Sciences,
Stuttgart, Germany
DR. DIETRICH SCHRÖDER
Professor, Stuttgart University of Applied Sciences,
Stuttgart, Germany
ABSTRACT
Building is the hub of almost all human activities in urban areas.
These activities are mostly supported by energies such as electricity whichmakes energy management very important especially in urban areas. This
paper has made an approach for enhancing energy management in thebuildings using Geoinformation Systems (GIS). Energy and water
consumption in the buildings can be visualized in different ways. Web GIS
can address this issue well over the Internet. Buildings in the project(Shranhauserpark, Stuttgart, Germany) area have consumption data
regarding heat, electricity, water and gas. GIS can perform the task ofvisualization in a number of ways; thematic map is one of the best wherecolour intensity indicates the degree of energy consumption. Moreover bar
charts associated with thematic maps depict the changes of consumption
values over the period of time (years, months, days etc) for each building in
the unit of Kilo Watt Hours per square meter (unit of measurement).A web
portal is developed for displaying maps and attributes where users or
people of the study area can have the access through Universal Resources
Locator (URL). Thus, they can evaluate the status of their energy
consumption regarding heat, electricity, gas and water. Dissemination oftheses information will lead to an increasing awareness among the residentsof the project area with respect to energy consumption and supply. Morethan half of the world’s population lives in the urban areas in Asia. The
number of people living in urban areas would be 2 billion by the year 2030.
This huge influx of people would make a significant impact on the energy
management system of the mega cities in Asia. The result of this study would
support the energy management system to monitor and evaluate building
energy consumption in a much more efficient way that can play a vital role
to mitigate the energy crisis in the world.

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December 2007, Dhaka, Bangladesh

1. INTRODUCTION
Internet GIS is comparatively a new term in Geographic Information
System. It is getting special significance for spatial data handling over theweb. In simple words this is for distributing and processing Geoinformationby the way of Internet and World Wide Web. It is getting increasing
importance and acceptability for different level of bodies like geospatial
data users and producers as well as governmental and non-governmental
agencies. It can provide GIS functionalities both on Intranet and Internet atthe same time. As Internet GIS is platform independent it reduces thenecessity of purchasing costly desktop GIS software.
Internet plays a vital role in our everyday life. Necessary information isavailable online regarding almost every sphere of life. Energy is anotherwidely used term. Very few things are possible without energy. On the other
hand buildings accommodate greater portion of human activities. Thus how
to manage energy in buildings is worth stating. Particularly in urban areas, it
is very significant. Geoinformation can be the right choice for this type ofenergy management. This task deals with structuring a system wherebuilding energy consumptions such as electricity, water, gas and heatingenergy and renewable energy supply are to be managed in real time with thehelp of Geoinformation Systems. The users can have access to the building
energy consumption data over the Internet and thereby they can evaluate thestatus of their respective energy consumption and supply. This will increase
the awareness about energy consumption along with the efficiency ofenergy use among the users.

2. BACKGROUND
PolyCity is an urban conversion project. It is focused on large-scale urban
development. Here the working places and living areas are integrated toresult in sustainable city quarters within short distance and low energy
consumption. The sustainable city quarters mean that these would be thebest for the people and environment both for now and the indefinite future.
The project handles a number of aspects related to urban conversion such as
new construction at the city edges of Barcelona in Spain; the conversion ofold city quarters with poly-generation energy and grid based energy supply
at Tornio in Italy; new building construction and renovating old ones on alarge former military ground near Stuttgart with biomass heat and electricity
supply.
The part of the project in Stuttgart is the area of Scharnhauserpark.
This is an urban conversion and development on an area of 150 hectares in
the community of Ostfildern on the southern border of Stuttgart. Working
places, residential areas and green park sections are integrated here to resultin a harmonious living and transportation concept with high comfort andlow energy consumption.

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This is also designed as an exemplary ecological community
development where wood fired co-generation plants will deliver electricity
and heat energy. This is in the frame of a European research project called
PolyCity for urban development or urban conversion. There are some otherrelated key components of the project like ecological communities,
Geoinformation and so on. These will be discussed in brief in the following
sections

3. METHODOLOGY
Each of the buildings in the project area will have an electronic device
called SmartBox. At present there are few buildings with the device such as
Stadthaus. The SmartBox will transmit the consumption and supply data at a
certain time interval. The data from this SmartBox will be stored in server.
Some programming tools will be used for establishing connection between
the electronic device and the server. Necessary data is to be retrieved fromthe server and to be put into the MS Access database in tabular form.
SmartBox

Consumption data
data

MS
AccessServer

GeoMedia Pro

Static
Display

Actualised
Database

GeoMedia Pro

Dynamic
Display

Access Database

Control Signal

WebPagewith Result

GeoMediaWeb Map

Figure 1: Flow diagram of methodology
Once the data about consumption from each building is stored in the
MS Access database, it will be used in the Geoinformation System forvisualization. In this case GeoMedia Professional is used to visualize theconsumption data on the server computer. GeoMedia WebMap Professionalis used for visualization over the web for the residents in the project
area.Database stored in MS Access would be actualized at a certain timeinterval. These real time data are to be used for creating graphic displays.

Management of Building Energy Consumption and Renewable Energy Supply in the Ecological Communities
Using GIS
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December 2007, Dhaka, Bangladesh

A number of thematic maps are prepared to view the numeric values invarying color intensities. This will give the visual impression about thewhole area; for example buildings with darker colour indicate more energy
consumption. Bar charts associated with thematic maps will demonstrate theconsumption values to facilitate the comparison among different timeintervals (years). As the database will be updated at an interval of time, thethematic maps along with bar charts will also be updated at the same time.
The maps and bar charts are based on the real time consumption values. So
this display is dynamic. A set of static maps will also be created using thedata form the Access database for a longer time span such as for a year orsix months. GeoMedia Professional will be deployed to generate above
stated outputs.

4. DATA AND SOFTWARE
Data is very important for any GIS project. For the current project necessary
data is available in the form of MS Access and GeoMedia workspace. Thereis building information in access database like house number, number ofstories, and name of the homeowner and so on. The consumption of energy
for each building is also available in Kilowatt Per Hour (Kwh). The above
stated data has to be in real time. Once all the connections are set up among
the system components the target will be achieved. GeoMedia Professional
5.2 is very powerful software for analysing and managing spatial data. The
GeoMediaWebMap Professional will be used for handling web related
aspects of this project. For creating graphical display MS Excel or Accesscan be attached with GeoMedia Professional.

5. AVAILABLE DATA
Data is most important item in spatial analysis. Once the database is ready it
is only a matter of time to have the desired output. The database for the areaof Scharnhauser Park is in Microsoft Access. The data set for carrying out
this study is with a working group from the University of Applied Sciences,
Stuttgart, Germany. They have obtained it from the city office of Osfildern
and a utility company called Esslingen am Neckar GmbH. The datbase
contains information about buildings as well as energy and water
consumptions. There is another data set in DXF file format containing
building block. This CAD data is later transformed into GeoMedia files witharea features for buildings. The MS Access data and GeoMedia files areused together to visualize the amount of energy consumption with a seriesof thematic maps and bar charts. The following sections give an idea about
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6. IMPLEMENTATION
Implementation covers the working procedures in GeoMedia Professional
for generating thematic maps and bar charts. A brief is provided discussion
on the consumption pattern on the energy along with thematic maps.
6.1

Working with GeoMedia Professional

The features with location data are in the GeoMedia warehouse andthe most of the attribute data are in the MS Access database(Scharnhauserpark.mdb). The attribute data includes building information
like building name, owner’s name number of stories and so on. The
database also has information about energy and water consumption for eachbuilding. For visualization of these attributes data we need to establish arelationship between the database and the warehouse.
6.2

Performing Analysis

Once the connection is set up we can start processing data inside
GeoMedia Professional. We are interested about consumption values perbuilding in a unit of KiloWatt Hour (kWh/m2) per square meter for heating.
As we have already the data about heating per building we only need thetotal heating area to have the consumption in desired unit. We can obtain the
ground plan area using Analyze Geometry function in GeoMedia. This is
saved in a query named Area of Ground Plan. Still the number of floors isnecessary to calculate the approximate heating area for each building.
After a number of field visits to the project area in Ostfildern the
database table Gebäude is updated with height information manually. In thistable the field Stockwerke contains the height information in number ofstories. Inside GeoMedia Professional the query containing ground area andthe table (Gebäude) with building height are joined. Now the ground area
and the building heights are available in a single query.
Using Functional Attribute query we can calculate the consumption
values for each building in kWh/m2. The arithmetic operation includes thedivision of annual consumption values by the product of ground area andnumber of floors. The output of this calculation is saved in a query under thename of Heatperunitarea.
6.3

Thematic Maps

A thematic map symbolizes geographic features according to nongraphic attribute data through the use of colour and other user-defineddisplay properties (Intergraph 2005).
It can give the visual impression of non-spatial attribute data over themaps. For making thematic maps customized ranges are used from 0 to 250
where the difference between two successive classes is 50. The number
actually refers to the unit of kWh/m2. Consumption values for a particularManagement of Building Energy Consumption and Renewable Energy Supply in the Ecological Communities
Using GIS
429

December 2007, Dhaka, Bangladeshbuilding can also be read form the legend entry in the thematic maps(
Figure 2).
Logical zooming is applied for the layers with street names and housenumbers. So the user can have more detailed information when he/she does
more zooming. The query Heatingperunitarea is used as a data source formaking thematic maps. But after finishing the thematic map preparation,
when it was attempted to publish on the Internet using GeoMedia WebMap
Publisher, it gave error message the processing pipe can not process theGeometry information. Transforming the query into Feature Class solved
the problem.

Figure 2: Thematic map for heat consumption (2003)
Following the same procedure the thematic maps for the year 2002
and 2004 were created. Each of them was put under different map windows
along with a set of rational legend entries.
6.4

Creating Bar Charts

There is one module developed by Prof. Dr. D. Schröder (Stuttgart
University of applied Sciences, Stuttgart, Germany) that can be used alongwith GeoMedia Professional to create Bar Chart or Pie Chart for making
comparison with different attributes of the feature classes.
Following the dialog box (Error! Reference source not found.3) bellow
the bars for the year 2002, 2003 & 2004 have been created and put onthematic map from the year 2003 as this year is having maximum number ofbuildings with consumption data for heating. The bar charts facilitate users
to visualize the fluctuation in consumption values for different years in abetter way.

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Figure 3: Thematic maps with bar charts
In the figure above each of the building has three bars indicating thecorresponding heat consumption (kWh/m2) for 2002,2003 and the third isfor 2004(
Figure 3). The right most one is for 2002; the middle one is for 2003
and the rest is for 2004. The intensity of colour indicates the degree ofconsumption in base map.

7.

MAP ON THE WEB

The web page is ready with maps and related attributes. It is not allowed to
publish the energy and water consumption data for each building on theInternet due to the privacy policy. The page is released inside the university(Stuttgart University of Applied Sciences) Intranet as a test case and it isproven successful (Figure4). The page provides all the functionalities so far
assigned to the thematic maps. It is possible to get access to the web pagefrom any of the computers inside the university network. As per the request
with the URL (http://193.196.137.99/Test_aneta), the page will appear on
the client’s machine. The type of the output map is SVG (Scalable Vector
Graphics). This is why if the client machine does not have a viewer for SVG
graphics, the page prompts for downloading the viewer (Adobe SVG
Viewer 3). The page has title on the left upper corner. Just beneath the title,
there is a tool bar holding a number of commands for online functions. The
right frame holds the legend entries while the different map windows are in
the left frame. The thematic map (heat consumption) for the year 2003 alongwith bar charts are set to default map window so it is activated at this point.

Management of Building Energy Consumption and Renewable Energy Supply in the Ecological Communities
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December 2007, Dhaka, Bangladesh

Figure 4: Overview of the page on the web

7.1

Tooltips

As the Tooltip for some features are already set, when the mouse is on
the object it shows the attribute specified. For example once the mouse isover a building it will give a rectangular box with Building ID, Building
Name, Use and the heating area of that building. In the figure below whenthe mouse is on the highlighted building it shows that the building ID is 8,
name of the building is Sporthalle im Park and the approximate heating area
(Figure5).

Figure 5: Map with Tooltip action
These functionalities are available for buildings having heatconsumption values for different years. Bar charts are added to the thematic
maps to visualize the comparison of heat consumption values for the years
2002, 2003 and 2004. When the user zooms into a single building three bars
appear corresponding to heat consumptions for 2002, 2003 and 2004.
Tooltips are also attached with these bars that show the values in kWh/m2
for that particular building.

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7.2

HotSpots

The Attribute of an object can also be viewed in a pop up dialog box
by clicking on it. It is possible because of defined HotSpot actions
associated with the feature class (buildings). For example the user can seeheat energy consumption per m2 in numbers for different years. The blankspace beside Heatperunitarea indicates that this year does not have any
consumption values for this particular building (Figure6).

Figure 6: Property Popup box for feature
The client has the option to turn off any layer that is not desired. It canbe performed by just checking out the check boxes against the layer.

8. CONCLUSIONSA Web Portal was designed furnished with the maps and non-spatial
attribute data for building energy and water consumption. The Portal
provides a certain level of interactivity for the users like pan, zoom orviewing attributes. The Thematic Maps with Bar Charts show the amount ofheat consumption for different years. Tooltips are assigned for mouse overaction with attributes such as building ID, name and so on.
Analysis shows that the administrative & Health facility buildings
consume much more heat energy than others. Electricity consumption isanalyzed as per month for different years. In the year 2002 and 2003, themaximum electricity consumption occurred in May while in the next year
(2004) buildings consumed most energy in April. The average electricity
consumption value is 68.84 kWh/m2 for these years. The data set for waterand electricity consumption is not complete.
Only few buildings have data regarding water (8) and electricity (14)consumption. The consumption pattern found here in this project can change
when the data set is completed.
In the PolyCity project working places, residential areas and greenparks are designed in such a way that it will result in an integrated living
environment with high comfort and energy efficiency. Low energy building
standards are prescribed for all plots in the project area.80 % of the total
Management of Building Energy Consumption and Renewable Energy Supply in the Ecological Communities
Using GIS
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December 2007, Dhaka, Bangladesh

energy demand will be supplied from renewable sources here in this projectsuch as solar cells and biomass plant for generating electricity. Thus 3038% of energy saving is expected in comparison to national standards.
The outcome of this paper will be integrated to the PolyCity project tomake the city of Ostfildern energy efficient and comfortable for urban
dwellers. Later this idea can be replicated in other cities in European
countries. The result can also be interesting for urban planners, managers
form utility supply companies, architects and engineers.

REFERENCES
Intergraph. (2005): GeoMedia Command Wizard. Online Guide of
GeoMedia Professional. Integraph Corporation, USA.
Murray, J. (2000). Developing Internetbased GIS Applications
http://www01.giscafe.com/technical_papers/Papers/papers058
Patil. R., and Loony C. (2003). Developing Dynamic GIS Web application,
Department of Computer Sciences, University of Navada,
http://www.scs.unr.edu
Plewe, B. (1997). GIS Online: Information Retrieval Mapping and theInternet. Stanta Fe, New Mexico: On Word Press
Web Links
http://www.answers.com/biomass
http://www.wissenschaftwirtschaft-bw.de/index.php4

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COMPARATIVE ANALYSISANDMONITORING OF URBAN HEATISLAND INTENSITYIN ASIANMEGA CITIES BY MODISWATARU TAKEUCHI1, 2, KAWIN WORAKANCHANA1, 2,
YOSHIFUMI YASUOKA2 and VIVARAD PHONEKEO3
1
RNUS, Asian Institute of Technology, Thailand
2
Institute of Industrial Science, University of Tokyo, Japan
3
GIC, Asian Institute of Technology, Thailand
wataru@iis.u-tokyo.ac.jp
ABSTRACTThis study focuses on comparing the heat island intensity for cities in
East and Southeast Asian mega cities and set up an operational monitoring
system for them to quantify the relationship between surface temperatureand biophysical land cover types. Aqua/Terra MODIS data received at
Tokyo and Bangkok were used to monitor thermal conditions in 37 selected
Asian mega cities. An operational monitoring system is set up in a near-realtime fashion and is available at http://webmodis.iis.u-tokyo.ac.jp/UHI.

1. INTRODUCTION
The urban heat island (UHI) refers to the phenomenon of higher
atmospheric and surface temperatures occurring in urban areas than in thesurrounding rural areas due to urbanization. It is characterized by a large
expanse of non-evaporating impervious materials covering a majority ofurban areas with a consequent increase in sensible heat flux (Voogt andOke, 2003). While atmospheric heat islands are normally measured by insitu sensors of air temperature via weather station networks, the surface UHI
is typically characterized as land surface temperature (LST) through the useof airborne or satellite thermal infrared remote sensing, which provides asynoptic and uniform means of studying SUHI effects at regional scales(Yuan et al., 2007). Satellite-measured LST has been utilized in various
heat-balance, climate modeling, and global-change studies since it isdetermined by the effective radiating temperature of the Earth's surface,which controls surface heat and water exchange with the atmosphere.
The Institute of Industrial Science (IIS), University of Tokyo has been
receiving NASA’s satellites’ Aqua/Terra MODderate resolution Imaging
Spectro radiometer (MODIS) data starting from 2001 May in order tomonitor the environment and disaster parameters around the East Asia. A
MODIS can monitor the same location twice a day from visible to thermal
infrared wavelength in discrete 36 channels. A MODIS-based monitoring
project has been launched to analyze and assess the environment anddisasters such as forest fire, flooding, agricultural activities, heat island

435

December 2007, Dhaka, Bangladesh

issues, sea surface temperature, vegetation phenology and so on (Ochi et al.,2002). In order to acquire MODIS data for expanded continental-scale into
Southeast Asian sub-region, IIS has provided MODIS receiving station at
Geoinformatics Center (GIC), Asian Institute of Technology (AIT) and data
to Geo Information, Space and Technology Development Agency ofThailand (GISTDA) through AIT.
The objective of this study is to compare the heat island intensity for
cities in East and Southeast Asian mega cities and set up an operational
monitoring system for them to quantify the relationship between surface
temperature and biophysical land cover types.

2. METHODOLOGY
2.1

Study area

Figure 1 shows a map covering Asian mega cities selected in thisstudy including Bangkok, Beijing, Busan, Chengdu, Chongqing, Colombo,
Dhaka, Khaborovsk, Hanoi, Harbin, HoChiMinh, HongKong, Hyderabad,
Jacarta, Kathmandu, Kolkata, KualaLumpur, Manila, Mumbai, NewDelhi,
Osaka, PhnomPenh, PyongYang, Sapporo, Seoul, Shanghai, Shijiazhuang,
Singapore, Taipei, Thimphu, Tokyo, Ulanbatar, Vientiane, Vladivostok,
Wuhan, Xian, Yangon.

Figure 1: An area of interest in this study which is covered by MODIS
receiving station installed at Tokyo and Bangkok.

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2.2

MODIS Land surface temperature (LST)

Figure 2 shows a flow chart of land surface temperature mapping.
Firstly, MODIS level1b data were processed into geo-coded level1b productand one-day mosaic image were generated covering 60N-S10 and 60E-150E
on daytime and nighttime observations respectively. Secondly emnissivity
map were generated by a response function averaging supplemented by land
cover map product and ASTER spectral library (Salisbury et al., 1992).
Then, land surface temperature map was generated by a generalized split
window method and was applied in this study (Wan et al., 1996). Finally,
monthly land surface temperature of daytime, nighttime and difference
between daytime and nighttime were generated by selecting maximum
temperature on pixel basis to remove cloud contamination.

Figure 2: A flowchart of land surface temperature mapping by ageneralized split window method using MODIS level1b, land cover map andspectral library over varieties of land cover types.

3. OPERATIONAL MONITORING SYSTEM
Figure 3 shows an operational monitoring system of urban heat island alongwith direct broadcasting of MODIS data at http://webmodis.iis.utokyo.ac.jp/UHI/. In our system, regional to continental scale disasters andenvironmental information can be achieved such as forest fire, heat island,
land surface water, vegetation phenology and land cover or land use map.
Figure 4 shows a land surface temperature difference between day andnight (left image), and land cover map (right) respectively for Bangkok,
Tokyo and Shanghai. Color scale ranges from cooler to warmer colors withincreasing temperature. Figure 4-(a) shows a thermal condition of Bangkok
in Thailand on 2006 February in rainy season. A light blue area around 8-10
degrees in a left image of Figure 4-(a) corresponds to an urban area in a left
image of Figure 4-(b) enhanced as a red color.
Figure 4-(b) shows an example of Tokyo in Japan on 2006 February in
winter season. It is found that less temperature difference is found along
coastal zones shown in bluish color whereas comparatively higher
difference is clearly identified in inner area shown in green color. Much
clear difference is visually interpreted in urban and sub-urban area as a heatisland phenomenon.

Comparative Analysis and monitoring of Urban Heat Island Intensity in Asian Mega Cities by Modis

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December 2007, Dhaka, Bangladesh

Figure 4-(c) shows an example of Shanghai in China on 2006 August
in summer season. This city is also affected by a wind coming from sea
located in the east of the city and relatively higher temperature difference
around 10 degrees in light blue correspond to an urban area which isrepresented as a red area by land cover map.

Figure 3: Web-based environment and disaster monitoring system such as
forest fire, heat island, land surface water, vegetation phenology and land
cover or land use map at http://webmodis.iis.u-tokyo.ac.jp/UHI/

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ICUS Report 27(a) Bangkok in 2006 February(b) Tokyo in 2006 February(c) Shanghai in 2006 August
Figure 4: Land surface temperature difference between day and night (leftimage), and land cover map (right) respectively for Bangkok, Tokyo andShanghai. Color scale ranges from black and cooler to warmer colors withincreasing temperature.

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December 2007, Dhaka, Bangladesh

4. CONCLUDING REMARKSThis study focuses on comparing the heat island intensity for cities in Eastand Southeast Asian mega cities and set up an operational monitoring
system for them to quantify the relationship between surface temperatureand biophysical land cover types. Aqua/Terra MODIS data received at
Tokyo and Bangkok were used to monitor thermal conditions in 37 selected
Asian mega cities. An operational monitoring system is set up in a near-realtime fashion and is available at http://webmodis.iis.u-tokyo.ac.jp/UHI/ACKNOWLEGEMENT
This study is financially supported by the Japan Society for the Promotionof Science (JSPS) under the research project (Grant number: 19569002).
The authors would like to thank JSPS for their support.

REFERENCES
Dousset, B. and Gourmelon, F., 2003. Satellite multi-sensor data analysis ofurban surface temperatures and landcover. ISPRS Journal of
Photogrammetry and Remote Sensing, 58, 43-54.
Yuan, F. and Bauer, M. E., 2007. Comparison of impevious surface area andnormalized difference vegetation index as indicators of surface urban
heat island effects in Landsat imagery, Remote Sensing ofEnvironment, 106, 375-386.
Nichol, J, 2005. Remote Sensing of Urban Heat Islands by Day and Night,
Photogrammetric Engineering and Remote Sensing, 71(5), 613-621.
Ochi, S., Uchihama, D., Takeuchi, W. and Yasuoka Y, 2002. Monitoring
urban heat environment in East Asia. GIS development, 6(10), 18-20.
Salisbury, J. W. and D’Aria, D. M., 1992. Emissivity of terrestrial materials
in the 8-14 μm atmospheric window, Remote Sensing of Environment,
42, 83-106.
Small, C., 2006. Comparative analysis of urban reflectance and surface
temperature. Remote Sensing of Environment, 104, 168-189.
Voogt, J. A. and Oke, T. R., 2003. Thermal remote sensing of urban areas.
Remote Sensing of Environment, 86, 370-384.
Wan, Z. and Dozier, J., 1996. A Generalized Split-Window Algorithm for
Retrieving Land-Surface Temperature from Space. IEEE Trans.
Geoscience and Remote Sensing, 34, 892-905.
Yuan, F. and Bauer, M. E., 2007. Comparison of impervious surface areaand normalized difference vegetation index as indicators of surface
urban heat island effects in Landsat imagery. Remote Sensing ofEnvironment, 106, 375-386.

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NUMERICAL SIMULATION OF
ATMOSPHERIC POLLUTION OVER KANTO
AREA USING THE MM5/CMAQ MODEL“SIMULATION OF OZONECONCENTRATION BETWEEN TWO
DIFFERENT WEATHER DAYS”
M.V.KHIEM
Institute of Industrial Science, University of Tokyo,
khiem@iis.u-tokyo.ac.jp
R.OOKA
Institute of Industrial Science, University of Tokyo,
ooka@iis.u-tokyo.ac.jp
H. HUANG
Institute of Industrial Science, University of Tokyo,
hhong@iis.u-tokyo.ac.jp
H. HAYAMI
Central Research Institute of Electric Power Industry,
1646 Abiko, Abiko-shi, Chiba-ken 270-1194, Japan.
haya@criepi.denken.or.jp
ABSTRACT
It is known that in summer, Ozone (O3) concentration in urban areas
can be strongly affected by local climatic condition in which somemeteorological factors play an important role such as precipitation, cloud,fog especially urban heat island (UHI). In this study, we use the
MM5/CMAQ model to investigate influence of climatic change on theatmospheric pollution over Kanto area with two case studies; (1) simulation
period with mild weather, and (2) the period that it’s hot and clear weather
pattern associated with climatic change. The 3 domains, which cover a
region of Kanto with grid resolutions of 9 km, 3 km, and 1 km respectively,
have been employed for this study. Numerical simulation results showed
that: (1) Atmospheric pollution was strongly effected by urban heat island
event; (2) the high temperature and weak wind speed lead to significantly
increase O3 concentration; (3) simulated O3 temporal trends showed good
agreement with observation. However, the simulated O3 in the night tends tooverestimate and in case of July maximum O3 is also higher thanobservation about 10 – 30 ppbV, this may relate to calculating on thevertical diffusion coefficient in the MM5 model and initial and boundary
conditions of CMAQ model. This will be investigated in the next work.

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1. INTRODUCTION
In recent years, the air pollution has become an important problem inparallel with the increasing energy use. The sources of the pollutants are theemissions from the industrial facilities, motor vehicles and heating systems.
The meteorological factors such as precipitation, cloud, fog especially urban
heat island (UHI) play an important role in the concentration of theatmospheric pollutants. (Chao, 1990; Cuhadaroglu, et al, 1977; Escourrou,
et al, 1990; Miyazaki, et al, 1991; Lacour, et al, 2006;). Conversely,
atmospheric pollution also has important effects in modifying urban climate
in various ways such as by increasing long-wave radiation from the sky inthe canopy layer, and increasing absorption of short-wave radiation in theboundary layer. It is found that UHI can raise the rate of chemical reaction
between nitrogen oxides (NOx) and Volatile Organic Compounds (VOCs),
this lead to significantly increase surface ozone concentrations in city
areas(Dewent, et al, 2003). In this paper, we would like to investigate
influence of climatic change on the atmospheric pollution over Kanto area
using two case studies; (1) simulation period with mild weather, and (2) the
period that it is the hot and clear weather pattern associated with climaticchange.

2. MODEL DESCRIPTION
2.1

Meteorology model

The Fifth-Generation NCAR / Penn State Mesoscale Model (MM5)version 3.7, a limited-area, nonhydrostatic, terrain-following sigmacoordinate model(Dudhia, et al, 2005), is used in this research to provide
spatial and temporal distribution of meteorological fields to the air quality
model. It has some characteristic such as: (i) a multiple-nest capability, (ii)nonhydrostatic dynamics, which allows the model to be used at a fewkilometer scale, (iii) multitasking capability on shared- and distributedmemory machines, (iv) a four-dimensional data-assimilation capability(FDDA), and (v) more physics options.
2.2

Air Quality modeling

The Community Multi-scale Air Quality (CMAQ) modeling systemversion 4.6 developed by Environmental Protection Agency (USA), which
was released in 2006, was used in this study. It is a multiple scale andmultiple pollutant chemistry-transport model that includes all the criticalscience processes such as atmospheric transport, deposition, cloud mixing,
emissions, gas- and aqueous-phase chemical transformation processes, andaerosol dynamics and chemistry. The CMAQ system can simulate
concentrations of troposphere ozone, acid deposition, visibility, fineparticulate and other air pollutants in the context of “one atmospheric”
perspective involving complex atmospheric pollutant interactions onregional and urban scales.

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3. ANALYSIS OUTLINE
3.1

Analysis domain

In this study, the MM5 simulation was performed with 3 nested
domains (Figure 1).
Detail conFigureure of model is summarized in Table 1. The 3
domains cover a region of Kanto with grid resolutions of 9 km, 3 km, and 1
km, respectively. The second domain size is 73x88 grid points and the third
domain is 100x121 grid point. All of the domains have 23 vertical sigma
levels from the surface to the 100-hPa level.
Ibaragi

Chiba

Figure1: Analysis domain

D1
D2
D3
3.2

Table 1: Analysis size domains and grid resolution
Computation
Grid
Horizontal
domain (X[km] x
numberresolution
Y[km])(km)
450x54051x61x23
9216x26173x88x23
3
99x120100x121x23
1

Model conFigureuration

In this study, the physic options in the MM5 simulation are following:
Grell cumulus parameterization scheme(Grell, et al, 1994); MRF planetary
boundary layer scheme(Hong, et al, 1996); explicit simple ice
microphysics(Hsie, et al, 1984); cloud-radiation scheme(Dudhia, 1989) andFDDA. The cumulus parameterization scheme is not used for the 3 and 1km domains. The CMAQ was conFigureured with the following options: (1)CB-IV speciation with aerosol and aqueous chemistry; (2) the Piecewise
Parabolic Method for both horizontal and vertical advection; (3) eddy
vertical diffusion; (4) photolysis; (5) no Plume-in-Grid; (6) the EBI
chemistry solver conFigureured for CB05; (7) use of the 3rd-generation
aerosol model; (8) use of the 2nd-generation aerosol deposition model; (9)use of RADM cloud model; (10) 14 vertical layers. More detailed
description of the scientific mechanisms and implementations of CMAQ canbe found in Byun and Ching(Byun and Ching, 1999).

Numerical Simulation Of Atmospheric Pollution Over Kanto Area Using The Mm5/Cmaq Model “Simulation Of
Ozone Concentration Between Two Different Weather Days”
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December 2007, Dhaka, Bangladesh

3.3

Study period and simulation condition

In this study, the MM5 simulation is done 96 hours with two periods:(1) with the mild weather, starting from 09 JST July 19 to 09 JST July 23,
2005; and (2) with the hot weather pattern associated with UHI event overTokyo area, starting from 09 JST August 03 to 09 JST August 07, 2005. A
meteorological condition with weak surface wind and high temperature inAugust case is favorable for photochemical production of ozone. Global
meteorological data (FNL) from NCAR with horizontal resolution of 10x10
was used to provide initial and boundary conditions for MM5 model and
FDDA process. Hourly emission data used here are the horizontal 3km x
3km emission estimated by Hayami et al.(Hayami, et al, 2004) (Figure 2).
After completing MM5 simulation, two periods from 00JST on 20 to 00JST
on 23 July and from 00JST on 04 to 00JST on 07 August have been run for
CMAQ model in domain 2 with the initial and boundary condition were
derived from the observation report of Japan Clean Air Program (Table 2).
Finally, the result of CMAQ model in domain 2 aimed to produce initial andboundary conditions for CMAQ runs in domain 3 with two periods from 00
JST on 21 to 00 JST on 23 July and from 00 JST on 05 to 00 JST on 07
August.

NOx

NMVOC

Figure 2: Hour emission data for CMAQ at 14 JST August 6(mole/s/grid)
Table 2： Initial and boundary condition for CMAQ model (JCAP, 1999)
Species
O3 NOx ALD FORM ETH OLE TOL XYL ISO
ICs
28 6.0
1.8
2.2
1.4
1.6
14.4
0.6
0.5
N 28 6.0
1.8
2.2
1.4
1.6 14.4 0.6
0.5
E 25 6.0
1.8
2.2
1.4
1.6
14.4
0.6
0.5
BCs
S 30 6.0
0.9
1.1
1.3
0.4
6.0
0.7
0.5
W 28 6.0
2.0
2.4
3.2
4.2
11.4
0.7
0.5

PAR
74.3
74.3
74.3
37.8
82.7

4. RESULT AND DISCUSSION
Figure 3 shows the spatial distribution of the 2m temperature and 10m windfrom MM5 simulation in domain 2 at 14 JST. In the case of July, thetemperature is low and the northeasterly wind is strong, most of Kanto area
was dominated by easterly and northeasterly winds. For the case of August,
the weather pattern associated with UHI event, we can see the region of444

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ICUS Report 27

temperature higher than 340C cover Tokyo metropolitan at 14 JST on
August 6 and the horizontal wind speed is a little weak. This meteorologicalsituation supports the development of a sea breeze circulation, therefore theatmospheric pollution in the northern cities of Kanto area will be strongly
influenced by UHI event. This difference in meteorological condition
between two above mentioned periods can influence on atmosphericpollution over Kanto area.

Figure 3: The MM5 simulated Temp (oC) & wind in D2 at 14 JST
Figure 4 is the spatial distribution of hourly O3 concentration
predicted by CMAQ model in domain 2 at 14 JST on July 22 and at 14 JST
on August 6. The result showed that atmospheric pollution concentration
under hot and clear weather condition is higher than that under mild
condition (July 22) and the area with high O3 concentration in August is also
larger. In the case of July, because of the northeasterly wind, O3
concentration is diffused to the southwestern part of Kanto. It was found thearea higher 90 ppbV in Shizuoka. In the August, however, it was found thata high O3 concentration area covers almost the northwestern part of Kanto
due to transition of the south and southeastern flow predicted by MM5.
Because of this direction wind some cities in the northern such as Saitama,
Gunma, and Tochigi have O3 concentration very high (more than 90 ppbV).
Comparison of averaged O3 concentration simulation of some cities between
the case of July and the case of August is illustrated on Figure 5. From thisFigureure we can see O3 concentration remarkably increases on the hot day(August 6) in comparison with that on the mild day (July 22). The
difference of O3 concentration can reach 10 - 30 ppbV.

Figure 4: The CMAQ simulated Ozone concentration (ppbV) in D2 at 14
JST
Numerical Simulation Of Atmospheric Pollution Over Kanto Area Using The Mm5/Cmaq Model “Simulation Of
Ozone Concentration Between Two Different Weather Days”
445

December 2007, Dhaka, Bangladesh
T okyo

100

100

80

80

60
40

60
40
20

20

0

0
1

3

5

7

9

11 13 15
T im e (JS T )17

19

G unm a

21

1

23

3

5

7

9

11 13 15
Tim e (JST )17

T ochigi

A ugust
July

120

19

21

23

A ugust
J uly

120

100

100
O 3 (ppbV )O 3 (ppbV )A ugustJuly120

O 3 (ppbV )O 3 (ppbV )S aitam a

A ugust
J uly

120

80
60
40

80
60
40
20

20

0

0
1

3

5

7

9

11 13 15
T im e (JS T )

17

19

21

1

23

3

5

7

9

11 13 15
T im e (JS T )

17

19

21

23

Figure 5: Comparison of averaged O3 simulation between mild and hot day
5. VALIDATION OF MM5 SIMULATION
In order to validate the simulation of MM5 model, we compared the 2mtemperature and 10m wind velocity with measured data at some stations in
Kanto area; Ebina(Kanagawa), Kumatani(Saitama), Kofu(Yamanashi),
Nerima(Tokyo), Hachiouji(Tokyo), and Fuchu (Tokyo) (Figure 6). For
temperature on Figure 9 and Figure 10, MM5 simulate well its diurnal
variation in all prediction periods (0-72h) at all stations. However, theminimum temperature intends to overestimate on the hot day (August). For
wind velocity, on Figure 11 and Figure 12 we can see the MM5 model
simulations agree well with measured data in term of diurnal variation, but
the MM5 does not simulate small variation of observed wind velocity. This
may relate to parameterization of boundary layer in model.
●

●

Kofu

●

Kumagaya●Hachiouji●● Nerima
Fuchu

Ebina
0

30km

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●

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Figure 7: Monitor stations used for CMAQ

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Numerical Simulation Of Atmospheric Pollution Over Kanto Area Using The Mm5/Cmaq Model “Simulation Of
Ozone Concentration Between Two Different Weather Days”
447

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during 4-6 August 2005 at some stations

Numerical Simulation Of Atmospheric Pollution Over Kanto Area Using The Mm5/Cmaq Model “Simulation Of
Ozone Concentration Between Two Different Weather Days”
449

December 2007, Dhaka, Bangladesh

6. VALIDATION OF OZONE CONCENTRATIONIn this study, the results from the CMAQ model in domain 2 were comparedwith measured data from 10 air quality monitoring stations located within
the Tokyo city; Shinjuku, Setagaya, Nerima, Hachiouji, Fuchu, and Komae,
which are shown in Figureure7. Figure 13 and Figure 14 show the ozone
time series comparison between the CMAQ simulation and observations at
the 6 Tokyo monitoring stations for the case of July and the case of August.
Generally, simulated O3 concentration tendency showed good agreementwith observations. However, the simulated O3 concentration in the nighttends to overestimate and in case of July maximum O3 is also higher thanobservation about 10 – 30 ppbV, this may relate to calculating on of thevertical diffusion coefficient in the MM5 model and initial and boundary
conditions of CMAQ model.

7. CONCLUSIONSThe MM5/CMAQ model applied to simulate influence of urban climaticchange on atmospheric pollution. In general, CMAQ simulated O3
concentration showed a good agreement with the observation for both two
periods. The results indicate that the high temperature and weak wind speed
under UHI event lead to significantly increase averaged O3 concentration ofTokyo city. Compare with mild day, the O3 concentration in hot and clear
day can increase 10 - 30 (ppbV) at some cities. From this research, it is said
that effect of UHI event on atmospheric environment is very significant.
However, the maximum O3 is higher than observation and for the July 22case, and simulated O3 concentration overestimates in the night. Somereasons which could cause these discrepancies such as meteorologicalcondition predicted by MM5, initial and boundary conditions for O3, NOx
and VOC, emission data and so on, these factors also need to be consideredin generation and distribution of O3 concentration.

REFERENCES
Byun, D and Ching, J., 1999, Science algorithms of the EPA Models-3
Community Multiscale Air Quality (CMAQ) modeling system, US
Environmental Protection Agency, EPA-600/R-99/030.
Chao, Z., 1990, Urban climate and air pollution in Shangai, Energy
Buildings, 15, 647–656.
Cuhadaroglu, B. et al., 1977, Influence of some meteorological factors on
air pollution in Trobzan city, Energy Buildings, 25, 179–184.
Derwent, et al., 2003, Photochemical ozone formation in north west Europe
and its control, Atmos. Env., 37, 14, 1983–1991.
Dudhia, J., 1989, Numerical study of convection observed during the WinterMonsoon Experiment using a mesoscale two-dimensional model, J.
Atmos. Sci., 46, 3077–3107.
Dudhia, J. et al., 2005, PSU/NCAR Mesoscale Modeling System. Tutorial
Class Notes and User's Guide: MM5 Modeling System Version 3.
Grell, G. et al., 1994, A description of the Fifth-Generation Penn

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State/NCAR Mesoscale Model (MM5), NCAR Technical Note,
NCAR/TN-398+STR.
Hayami, H., Kobayashi, S., 2004, Modeling of Concentration of
Atmospheric Secondary Aerosol, CRIEPI Report T03037, 17.(inJapanese).
Hong, S.-Y. et al., 1996, Nonlocal boundary layer vertical diffusion in a
medium-range forecast model, Mon. Wea. Rev., 124, 2322-2339.
Hsie, E.-Y. et al., 1994, Numerical simulation of frontogenesis in a moist
atmosphere, J. Atmos. Sci ., 41, 2581–2594.
JCAP, 1999, Air Modeling (4), Observation results of Kanto area insummer, Technical Report of Japan Clean Air Program. (in Japanese)
Miyazaki.T et al., 1991, Meteorological factors causing high dust
concentration, Energy Buildings, 15, 691-698.

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Ozone Concentration Between Two Different Weather Days”
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AUTOMATIC AND REAL-TIME BRIDGEHEALTH MONITORING FOR HEAVY
TRAFFIC ROUTESSANAE MIYAZAKI
ICUS, IIS, The University of Tokyo, JapanNTT DATA Corporation, Japanmiyazaks@iis.u-tokyo.ac.jp
YUJI ISHIKAWA
NTT DATA Corporation, Japan
ishikawayuj@nttdata.co.jp
TAKAHIDE OKUBO
Metropolitan Expressway Company Limited, Japanokubo85@shutoko.jp
KIMIHIKO IZUMITechnology Center of Metropolitan Expressway , Japanizumi@tecmex.or.jp
EIICHI SASAKI
Yokohama National University
esasaki@cvg.ynu.ac.jp
CHITOSHI MIKI
Tokyo Institute of Technology, Japanmiki@cv.titech.ac.jp
ABSTRACTA real-time bridge remote monitoring system for a quick detection of
the damage caused by earthquakes and for a reliable measurement of thedamage caused by its aging was developed. The system is consisted ofvarious sensors, high-speed data transmission networks, and an information
center that produces high-level information associated with the bridgeshealth. A demonstration system was developed on a Metropolitan
expressway in Tokyo, Japan, where many heavy vehicles over regulation
weight passes on. By this system, the reliability and the durability of oursystem was confirmed.

1. INTRODUCTION
Around 40% of Japanese bridges were constructed about 40 years ago, andthey have various kinds of damage known or unknown, serious or nonserious in recent years. Even these old bridges have to be remained inservice with effective maintenance because of a recent review of public453

December 2007, Dhaka, Bangladesh

investments. Both strong earthquakes and the daily use can trigger serious
disasters similar to a Minneapolis bridge collapse on Japanese bridges in a
few years, and also its damage might be very huge especially in mega city
areas. A quick and time-serial reporting of quantitative diagnoses to roadadministrators associated with bridges-health measured using scientificsystems would be extremely important to establish a sustainable city. In thispaper, a concept of our real-time bridge remote monitoring system using
various sensors, such as video cameras and various kinds of fiber-optic
sensors for a quick detection of the damage caused by earthquakes and for areliable measurement of the damage caused by its aging was described. A
demonstration system developed on Metropolitan expressway in Tokyo,
Japan was also introduced.

2. SYSTEM ARCHITECTURE
The advantage of our system is on its ability to monitor the time-serial
condition of bridges automatically from remote locations in real-timewithout electric power supply at the field. Ensuring this, as shown in
Figure 1, our bridge monitoring system is consisted of five subsystems;
sensor subsystem, data transmission subsystem, data analyzing subsystem,
diagnosing subsystem and administration support subsystem. The detail is
as follows.
2.1

Sensor Subsystem

In our monitoring system, various sensors, namely video camera andfiber-optic sensors such as strain gauges, displacement meters,
inclinometers and accelerometers are attached to each bridge as a sensor
subsystem. Figure 2 shows the example of these sensors.
Road
Administrator

BridgeSensorSubsystem

Data
Analyzing
Subsystem

Diagnosing
Subsystem

Administration
SupportSubsystem

Data Transmission Subsystem

Figure 1: System architecture454

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

FBG displacement meter

FBG inclinometer

FBG accelerometer

BOTDR displacement meter

FBG strain gaugeVideo camera

Figure 2: Example of sensors
2.2

Data Transmission Subsystem

The data measured by the sensor subsystem is automaticallytransmitted to the data analyzing subsystem using the data transmission
subsystem. We can choose the data transmission technology, e.g. theInternet, fiber-optic communication, wireless communication, etc.,
appropriately to the needs of a road administrator according to its reliability,
capacity, cost, etc.
2.3

Data Analyzing Subsystem

The data transmitted from the sensor subsystem using the datatransmission subsystem is stored in the database, and then various
calculations and analyses are automatically done using the data analyzing
subsystem.
2.4

Diagnosing Subsystem

As a next step, the diagnosing subsystem generates the gap
information between the measurement data and the pre-known normal datausing the output of the data analyzing subsystem. The gap information isrepresented in three ranks, namely “large”, “small” and “non”.
2.5

Administration Support Subsystem

The administration support subsystem visually provides theinformation generated by the data analyzing subsystem and the diagnosing
subsystem to support road administrators for the decision of their next
actions, etc.

Automatic And Real-Time Bridge Health Monitoring For Heavy Traffic Routes

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December 2007, Dhaka, Bangladesh

3. FEASIBILITY STUDY ON HEAVY TRAFIC ROUTESAs a feasibility study, a demonstration system was developed on
Metropolitan expressway, which consists mostly of bridges, in Tokyo, Japan.
The reliability and the durability of the system was also examined.
3.1

Overview of our demonstration system

Figure 3 shows a geographical location of our demonstration system.
The detail of our test site and our system are as follows.
3.1.1 Test site characteristics
Our test site is Komazawa and Sangen-jaya on the route No.3 ofMetropolitan expressway that is one of the heaviest traffic routes in Tokyo
Metropolitan City, where many heavy vehicles over regulation weightpasses on. The route No.3 of Metropolitan expressway, which wholly
consists of bridges, was constructed in the middle of 1960’s, and about
110,000 vehicles, including 30% heavy vehicles, pass through this route perday; namely 50,000 vehicles go toward the metropolitan core, and 60,000
vehicles go away from the metropolitan core. Therefore, both aging damage
and daily damage caused by the traffic are extremely serious in our test site,and practically various maintenance is enforced on the route perpetually.
3.1.2 System configuration
Our demonstration system is consisted by five parts in accordancewith our system architecture described in Section 2. As shown in Figure 3
and 4, the sensor subsystem is set between Komazawa and Ikejiri on theroute No.3 of Metropolitan expressway. We use twenty-four FBG
displacement meters, eight BOTDR displacement meters, eight FBG
inclinometers, twelve FBG strain gauges, four FBG accelerometers and two
FBG heat gauges for our measurement. The data measured using thesesensors is collected at Ikejiri local station located 1.8 km away from
Komazawa (and 5 km dummy fiber is added for our experiment), and istransmitted to the data analyzing subsystem in our information center
located at Otemachi IDC by using the data transmission subsystem; here weuse a fiber optic communication network provided by NTT, and then thedata is calculated and analyzed for generating measurement data anddiagnosis information using the data analyzing subsystem and the
diagnosing subsystem, respectively. After that, measurement data anddiagnosis information are transmitted to the administration support
subsystem located at the road administrator’s office, Toranomon by using asimilar data transmission subsystem, and then they are visually provided to
the road administrators for supporting their decision making.

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Sensors on bridges
Information Center

FBG displacement meter
Analysis server

FBG inclinometer

Data storage

Fiber optic communication network
FBG accelerometer
BOTDR displacement meter

Admin
OfficeFBG strain gauge

PositionVideo camera

Heavy Vehicle traffic

Road map (c) Metropolitan Expressway Company Limited

Figure 3: Geographical location of our demonstration system
Local Station（Ikejiri）

Information Center（Otemachi IDC）

Admin Office（Tranomon）

Bridges
information

data
SensorCameraSensor subsystem

Data analyzing subsystem
Diagnosing subsystem

Admin support subsystem

Figure 4: Data and information flow
Disaster Management

Maintenance Management

Fatigue Estimation

Quick damage detection

Early damage detection

Continuous traffic detection

inclinometer

accelerometer

inclinometer

accelerometer

main girders andpiers angularity

vibration

main girders andpiers angularity

vibration

video camera

vehicle images

displacement meter

displacement meter

main girders gap

main girders gap

Damage level

Long-term data change

strain gauge

main girders stress
Accumulative traffic

GeographicalGeographicalRepresentation
Representation

Figure 5: Output information

Automatic And Real-Time Bridge Health Monitoring For Heavy Traffic Routes

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3.1.3 Measurement items
Figure 5 shows the data and information provided by ourdemonstration system corresponding to each sensor. As shown in figure 5,
we provide them for three purposes, namely the disaster management, themaintenance management and the fatigue estimation, that are indispensable
to the bridge management. Only one sensor system is required both for thedisaster management and the maintenance management.
3.2

Data and information provision

In this section, some examples of measurement data and diagnosis
information provided to the road administrators in our demonstration system
are introduced.
3.2.1 Measurement data provision
Figure 6(a) shows the display representation of measurement data. It
is updated corresponding to data collecting cycle, namely 1Hz for FBG
displacement meters, every thirty minutes for BOTDR displacement metersand 125Hz for the other sensors. Figure 6(b) shows a result of a real-time
detection of heavy vehicles passing thorough our test site, and a histogramof its passing-vehicle number corresponding to its weight levels. These data
can be redrawn if only they specify the date and time that they are interestedin.
3.2.2 Diagnosis information provision
Figure 6(c) shows the display representation of diagnosis information.
It is shown on a 2D geographical map using different colors corresponding
to each gap level, namely “large”, “small” or “non”.

displacement [mm]displacement [mm]Real-time Measurement
Heavy vehicle detection

P-420 FBG displacement (upper)

real-time monitoring system○ real-time○ input date
yymmddtime[s]P-420 FBG displacement (lower)
shibuyahhmmss

OK

P-415
P-417

Main girders position

P-419

Heavy vehicle traffic (statistics)

P-420

P-415

gap : -1.4mm

number of vehicles

P-421

[tf]
70 60 - 69
50 - 59
40 - 49
30 - 39
20 - 29
0 - 19time[s]Main girder gaps

P-417

gap : -3.2mm
Septembertime[s](a) Measurement data458(b) Heavy vehicle detection

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ICUS Report 27

S2
S5

Disaster

S1

main girder gap
C2

vibration
Maintenance

6

5

C1

7

4

vibration

6

Y
3

2

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9
1

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B

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K3

P-420

P-418

←Yoga
P-419

P-417

P-416
→Shibuya
P-415

END

(c) Example of the diagnoses information

Figure 6: Display representation of the administration support system

4.

CONCLUSIONS

We introduce a concept of our real-time bridge remote monitoring systemusing various sensors for a quick detection of the damage caused byearthquakes and for a reliable measurement of the damage caused by its
aging, and also introduce a demonstration system developed on
Metropolitan expressway in Tokyo, Japan, for our feasibility study. The
system has been in operation since March 2007 without any trouble andfailure. In the next step of our research, we will try to establish thereliability and the durability of our system, and to estimate a costeffectiveness for the road administration.
ACKNOWLEDGEMENT
The authors acknowledge to the reviewer for necessary corrections andcomments for improving the quality of the paper.

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3-D APPLIED ELEMENT METHOD FOR
PP-BAND RETROFITTED MASONRYWORAKANCHANA KAWIN
Project Researcher, ICUS, Institute of Industrial Science,
The University of Tokyo, Japankawin@.iis.u-tokyo.ac.jp
PAOLA MAYORCA
Project Research Associate, ICUS, Institute of Industrial Science,
The University of Tokyo, Japanpaola@.iis.u-tokyo.ac.jp
RAMESH GURAGAIN
Director, Earthquake Engineering and Research,
National Society of Earthquake Technology, Nepal
rguragain@nset.org.np
SATHIPARAN NAVARATNARAJ
Doctoral Student, Meguro Laboratory
The University of Tokyo, Japansakthi@.iis.u-tokyo.ac.jp
KIMIRO MEGURO
Professor, ICUS, Institute of Industrial Science,
The University of Tokyo, Japanmeguro@iis.u-tokyo.ac.jp
ABSTRACT
Masonry, through its long history, is widespread used around theworld and still remains a main building material in many places especiallydeveloping countries. However a poorly designed masonry is known asbrittle and susceptible to earthquakes. To improve masonry seismic
capacity, polypropylene band retrofitting technique was purposed based on
economic point of view and local availability of material and skilled labor.
In this study, we proposed the 3-D Applied Element Method as an analysis
tool to help understanding the polypropylene band retrofitted masonry
behavior which will be benefit in the future design process. Unlike theprevious version, 3-D Applied Element Method elements can be any
rectangular prism which helps reducing the number of elements. Brick andmortar springs are represented by using different spring properties.
Nonlinear constitutive law of the mortar spring employed the Gambarotta
model which considers the material softening. Polypropylene band ismodeled as beam element using conventional plastic constitutive law
connected together with the masonry by elastic spring representing thepolypropylene band to brick connector. The numerical simulation of nonretrofitted and retrofitted out of plane wallets shows that with the suitableselected parameter the behavior of masonry can be closely reproduced.

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1. INTRODUCTION
Masonry along with timber structures are among the oldest structures thatare still used nowadays. Masonry structures history can be tracked back asearly as 8000-9000 B.C. near Lake Hullen, Israel (Lourenço, 1996). With
its long history, abundance of material, ease of construction and theadvantages in thermal property, masonry is widespread used around theworld. This type of structure still remains a main building material in many
places especially in developing countries (Paola, 2003). Despite its
advantages as residential structure, masonry is known as brittle andunsuitable for construction of buildings in seismic zones (Tomaževič, 1999).
The 1997 Umbria-Marche, 1999 Bhuj and 2003 Bam earthquakes shows thatmasonry is rather susceptible and a huge number of masonry collapses isfound especially in the region where the poorly designed masonries areconcentrated. Moreover, masonry collapse also results in high casualty
because masonry material tends to break into the small debris and left
insufficient void which reduce the chance of survival.
In order to improve the current situation, the proper retrofitting
method must be invented. Several proposed retrofitting method in theliteratures includes grout injection and internal reinforcing, ferrocement
coatings, FRP composites and adding of steel elements. These methods
were reporting successfully for increasing the seismic capacity of thebuilding. Besides, the recent retrofitting scheme considering economic andavailability of material and skilled labor is Polypropylene band (referredlater as PP-band) retrofitting technique. The method was first proposed by
Paola in 2003. Unlike the former methods, a main objective of thisretrofitting technique is to hold the disintegrated elements together andpreventing the collapse. In attempt to understand the behavior and torationalize the design of these retrofitting methods, she carried out the PPretrofitted masonry wall testing. It was found that the behavior of theretrofitted walls was more stable and larger deformations could be sustained
compared to unretrofitted one. Moreover, Paola also proposed the 2-D
numerical model based on Applied Element Method (AEM) for simulating
PP-band retrofitted wall using constitutive laws provided by Lorenço (1996).
In 2005, Sathiparan conducted series of shaking table tests of the ¼ scaled
single unit masonry models with opening. He found that the retrofitted test
models can resist up to 88 mm compared to 7 mm in an unretrofitted casefor top displacement without collapse. Later, Guragain (2006) adopted theconstitutive laws from Gambarotta (1997) into AEM and succeeded inproposing the model for simulating the in-plane cyclic behavior of PP-band
retrofitted masonry.
By considering the damage mechanisms in the masonry structures, thetypical damage mechanism in the masonry structure can be identified as 1.
cracks between walls and floors 2. cracks at the corners and at wallintersections 3. out-of-plane collapse of perimetral walls 4. cracks inspandrel beams and/or parapets and 5. diagonal cracks in structural walls(Tomaževič, 1999). Except the diagonal cracks, most masonry damage
behaviors inevitably relate with three dimensional behaviors. With the462

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proposed PP-band retrofitting, the interaction between each wall will behigher and therefore the seismic resisting mechanism tends to become more
important. Therefore, three dimensional behaviors have to be investigatedbefore developing the less complicated two dimension analysis and design
process. Moreover, because PP-band stiffness is rather low compared tomasonry, the effect of retrofitted PP-band will play more significant role
when a structure largely deforms. This is inevitably required the goodunderstanding of three dimensional seismic behavior of masonry structure in
the large deformation state. Despite a number of numerical models forstructural analysis, few are suitable to simulate masonry in the large
deformation range and AEM is one among these. In this study, we proposed
the 3-D AEM, based on previous 2-D AEM for masonry and 3-D AEM for
concrete, to simulate three dimensional behaviors for PP-band retrofitted
masonry structure.

2. 3-DIMENSIONAL APPLIED ELEMENT METHODIn AEM, the structure is divided in rigid elements, carrying only thesystem’s mass and damping, connected with normal and shear springs
representing the material properties (Figure 1). The stress and strain fields
are calculated from the spring deformations. 3-D AEM rigid elements with
6 degrees of freedom each are connected through sets of one normal andtwo shear springs.

Figure 1: 3-D AEM
3-D AEM used an explicit scheme to solve structural problems
therefore it is required to assemble the system stiffness matrix. For thispurpose, it is necessary to sum up the contributions of all the springs aroundone element to the relevant degrees of freedom. Because each element has
six degrees of freedom, the stiffness matrix of each spring is a 12 by 12
matrix which its components were generated by direct stiffness method.
Masonry is constituted by two phases: brick and mortar. Therefore,

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there are two types of springs: one inside brick units, brick spring, and theother at the joint interface, brick-mortar spring, are defined in 3D-AEM. In
this paper, the brick spring stiffness is assumed to be elastic and its stiffness
can be calculated as:
Kn = E × b × c and Ks=a

G ×b×ca(1)where E and G are Young’s and shear modulus of brick, respectively. Other
variables are shown in Figure 2. For the brick-mortar springs, an equivalentnormal and shear stiffness is calculated by assuming that these springs
represent a system of brick and mortar springs arranged in series as shownin Figure 2.
a
th

b

Kb

Kb
Km

c

Brick
CL

Brick
CL
MortarFigure 2: Concept of equivalent brick-mortar spring
The corresponding equivalent stiffness is:1
a − thth=+Kneq Eb × b × c Em × b × c(2)

1
a − thth=+
K 1seq Gb × b × c Gm × b × c(3)1
a − thth=+
K 2 seq Gb × b × c Gm × b × c(4)where Eb and Gb are the Young’s and shear modulus of brick and Em and Gm
for the mortar. Eigenvalue analysis is also possible with the current version
of 3D-AEM. The vector iteration with shifts technique is adopted. This
technique is chosen as it provides a practical tool for computing as many
pairs of natural vibration frequencies and modes of the structure as desired.
2.1

Masonry Modeling

The material constitutive relation requires spring level stress/strain
updating for each loading step in the 3-D AEM. The stiffness changes inaccordance to damage that material sustained in local level is required tomonitor throughout the loading history. As mentioned earlier, theconstitutive law needed to be modified in order to take into account thisphenomenon. Such a model should be able to reflect the highly nonlinear

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behavior of masonry with the fewest number of parameters so that it results
in a simple and stable numerical model. Considering these criteria, thedamage model of brick masonry proposed by Gambarotta et al (1996) has
been chosen to implement in the 3D-AEM for cyclic behavior of themasonry. This constitutive law is able to reflect the important physicalphenomena exhibited by masonry under cyclic loading.
The chosen constitutive model is based on damage mechanics andtakes into account both the mortar damage and brick-mortar de-cohesion
which is considered to take place when opening and frictional sliding are
activated. Constitutive property of joint springs is based on two damage
variables representing frictional sliding and mortar joint damage. Those
variables are obtained from Mohr-Coulomb’s friction surface and damage
condition based on fracture mechanics. The damage evolutions in tensileand compression zones as well as the frictional limit criteria are given in
Figure 1.

Figure 1: Constitutive relation to model the cyclic behavior of masonryStress at any springs can be defined as:{σ } = [D] {ε}(5)Strain in springs can be split into elastic and plastic strain as:{ε} = [Ke] {σ }+ {εp}(6)where, [Ke] is the elastic compliance matrix of the spring. The plastic strainis {εp} = {εnp, γp}t and is the result of inelastic normal and tangential
displacement. Strain components are defined as functions of the damage
variable α,εnp = h(α) H(σn) σn(7)γp = k(α) (τ-f)(8)

where h(α) and k(α) are positive functions representing inelastic
compliances in normal and tangential direction. H(σn) is the heavisidefunction used to make the expression unilateral in tensile straining action
and f is the friction developed at the interface between mortar and brick.
Evaluation of the variable α and friction f is made through the limiting
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December 2007, Dhaka, Bangladesh

conditions of damage and friction sliding.
The damage condition based on R-curve approach of fracture
mechanics is defined on the basis of energy release rate of damage, Y andtoughness, R as:

φd = Y- R ≤ 0
Y =(1/2) h′(α) H(σn) σn2+ (1/2) k′(α) (τ-f)2(9)

and the compliance functions h(α) and k(α) are assumed linear function of
inelastic compliance constants as follows:h(α) = cn αk(α) = ct α

(10)The toughness function, R is related to damage evolution and isdefined in terms of damage index α setting to attain its peak value Rc at
critical value of α =αc(=1) and vanishing to zero as α increasing. The
friction sliding condition is obtained from Mohr-Coulumb friction conditionas:

φs = | f | +μ σn ≤ 0(11)where, μ is friction coefficient and | f | represents the shear component insurplus to cohesion.
2.2

PP-Band Mesh Modeling

The PP-band mesh is modeled through beam elements spanning
between band intersections points as shown in Figure 5. These ends werethen connected to the masonry structure through a set of three springs:
normal, shear, and rotational. By appropriately setting the properties ofthese springs, it is possible to consider all possible connecting conditions
between mesh and structure. For instance, if there is a wire connector at thatparticular location, all three springs have values proportional to theconnector properties. On the other hand, if there is no connector and no
mortar overlay, the normal spring only works in compression, i.e. when themesh and the structure are in contact. As for the shear and rotation springs,
there values are almost zero. This would not be case if there was mortar
overlay.

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Improved model

Beam element

PP-band

PP-crossspringPP-crossspringPP-crossspringConnector
springPP-crossspringPP-crossspringPP-crossspring

AEM mesh
2 shear springs

Connector
springPP-cross spring(Normal spring)

3 rotational
springs

Figure 5: 3D-AEM mesh modeling
The direct implication of a model as the one described above is theconsiderable increase of degrees of freedom of the system because eachintersection point is associated with six more degrees of freedom. A 3dimensional analysis by itself also involves the solution of systems withlarge number of degrees of freedom. Therefore, it was absolutely necessary
to optimize the algorithms used to solve the equations of motion. This step
was successfully implemented.
The material model used for each PP-band beam element was elastic
in tension as shown in Figure 6. No compression forces were taken by thebeam element. The beam elements were defined so as to have almost no
moment resistance at their ends.

EεFigure 6: Material model for PP-band beam element

3. MODEL VERIFICATIONThe 3D-AEM model was verified using the experimental data obtained by
Sathiparan (2005). The non-retrofitted and retrofitted wallettes, shown in
Figure 2 and Figure 3, were 475x235x50mm3 and consisted of 6 rows of 6
bricks each. The PP-band mesh was made of 6mm-width, 0.32mm-thick PPbands placed at 40mm pitch. A total of 6 wire connectors were used toattach the meshes to the wallettes. The wallettes were simply supported byhigh strength steel rods in both ends. The masonry wallettes were tested
under line load using another steel rod of 200mm diameter in the mid span.

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December 2007, Dhaka, Bangladesh

Figure 2: Retrofitted masonry wallet tested for out of plane

Figure 3: Boundary condition and loading of the masonry wallet for outof plane test
The material properties used for the masonry are summarized in Table
1. The PP-band mesh stiffness was set equal to 9.375 MPa.
Table 5.1: Material properties used for the modeling of out-of-planemasonry wallettes
Young’smodulusE(kN/mm2)

Shear
modulusG(kN/mm2)

Tensilestrengthσcr(kN/mm2)

Shearstrengthτcr(kN/mm2)

Friction coeff.
μ

β

1/Cmt
(kN/mm2)

Morta
r

0.5

0.25

0.16e-30.22e-3

0.6

0.9

1/30

Brick

15.0

7.5

NA

NA

NA

NA

NA

NA: Not applicable

The models used for non-retrofitted and retrofitted models are shownin Figure 4.

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ICUS Report 27(a) Non-retrofitted wallette(b) Retrofitted wallette(c) Boundary and loading condition (top dark elements: loading point,bottom dark elements: support)
Figure 4: Boundary condition and loading of the masonry wallette
for out of plane test
Figure 5 and Figure 6 show the comparison of numerical andexperimental simulations for non-retrofitted and retrofitted wallettes,
respectively. It can be seen that in both cases, the model could accurately
capture the force-deformation relationships.

Figure 5: Numerical and experimental force-deformation curves for nonretrofitted wallettes. (Experiments by Sathiparan, 2005)

3-D Applied Element Method for PP-Band Retrofitted Masonry469

December 2007, Dhaka, Bangladesh

Figure 6: Numerical and experimental force-deformation curves for
retrofitted wallettes. (Experiments by Sathiparan, 2005)
The agreement between experiments and numerical simulation canalso be observed in the crack patterns and deformed shapes (Figure 13
and 14).

(a) Experiment(b) Numerical simulation (scale factor: 20; midspan verticaldisplacement=3mm)
Figure 7: Comparison of numerical simulation and experimental
deformed shapes for non-retrofitted masonry.

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ICUS Report 27(a) Experiment(b) Numerical simulation (scale factor: 20; midspan verticaldisplacement=3mm)(c) Numerical simulation (scale factor: 5; midspan verticaldisplacement=10mm)
Figure 8: Comparison of numerical simulation and experimental
deformed shapes for retrofitted masonry
CONCLUSION
The 3-D AEM for simulating static behavior of PP-band retrofitted masonry
was developed. The main improvements in this version are the rectangularprism AEM element which helps reducing the element number and the
additional beam element and connected spring allowing AEM for simulating
PP-band. The verification for 3-D AEM for PP-band retrofitted masonry forthe out of plane test was carried out. The verification result shows that with

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December 2007, Dhaka, Bangladesh

the suitable selected parameter, the behavior of masonry can be closely
reproduced.

REFERENCES
Gambarotta L. and Lagomarsino S. (1997), “Damage Response for the Seismic
Response of Brick Masonry Shear Walls. Part I: The Mortar Joint Modeland its Application”. Earthquake Engineering and Structural Dynamics,
26, 423-439
Guragain, R. (2006), Numerical Simulation of Masonry Structures under Cyclic
Loading using Applied Element Method, Master degree thesis,
Department of civil engineering, The University of Tokyo.
Lourenço, P.B. (1996), Computational Strategies for Masonry Structures, Delft
University Press
Mayorca, P. (2003), Strengthening of Unreinforced Masonry Structures in the
Earthquake Pone Regions, Ph.D. thesis, Civil Eng. Dept., the University ofTokyo.
Tomaževič, M. (1999), Earthquake-Resistant Design of Masonry Buildings,
Imperial College Press, London
Sathiparan, N. (2005), Experimental study of retrofit of masonry building by
pp-band mesh, Master degree thesis, Department of civil engineering,
The University of Tokyo

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STRUCTURAL HEALTH ASSESSMENT OFINFRASTRUCTURE: THE BANGLADESHPERSPECTIVE
RAIS AHMAD1, M. KABIRUL ISLAM1, M. ZAKARIA AHMED1
1
Department of Civil Engineering,
Bangladesh University of Engineering & Technology, Bangladeshmzahmed@ce.buet.ac.bd
2

TRIBIKRAM KUNDU2
Department of Civil Engineering and Engineering Mechanics
University of Arizona, USA

ABSTRACTDue to rapid urbanization various multi-storied reinforced concretebuildings are being built in major cities of Bangladesh such as Dhaka andChittagong. Many of these buildings have soft story in the ground floor andgenerally have been built without seismic consideration. However thesecities as well as most of the region encompassing Bangladesh are located inmoderate to severe earthquake zone. In recent years, several earthquakes ofmagnitude 4.0 to 6.0 have been recorded in Dhaka and Chittagong, whichhave caused either collapse or damage of concrete and masonry buildings,
cyclone shelters, and mud-walled houses. Damages to utilities such as
electric transformers have also been recorded. It has been observed inrecent times that poor quality or faulty construction and design have also
resulted in complete structural collapse of buildings. This paper discusses
some of these occurrences and the methods that could be employed to assess
the structural health condition of critical buildings and other infrastructure.

1. INTRODUCTION
Rapid urbanization in big cities of Bangladesh, like Dhaka and Chittagong,
have been taking place in recent three decades. This thrust has created ademand for multi-storied reinforced concrete (RC) buildings especially of
residential type. Many of these apartment complexes are found to have softstories in the ground floor, which is generally used as parking space. A large
number of industrial buildings have also been built throughout Bangladesh
during the past decades because of rapid industrialization environment andgood government policy.
The epicenters of some of the past (over the last 150 years) major
earthquakes measuring greater than 7.0 on the Richter Scale were observed
to be located within 150 km from Dhaka city. In recent years several
earthquakes with magnitude 4.0 to 6.0 have been recorded. These recent
earthquakes (2001-2005) have caused collapse of concrete buildings,
damage of cyclone shelters, masonry buildings, electric transformer, mudwalled houses in the countryside including loss of human life. Frequent473

December 2007, Dhaka, Bangladesh

shaking in the Chittagong region in recent times has raised alarm among thepeople. It is obvious from these occurrences that Bangladesh is located in aregion vulnerable to earthquake hazards. A strong earthquake may strike
this country in the future, resulting in huge loss of life and damage toproperty and infrastructure, and thus can set back the pace of development
achieved in this country so far. For ensuring sustainable development of
Bangladesh, it is important to take necessary measures for disaster risk
reduction.
Some examples of recent building collapse can illustrate the severity
and magnitude of disaster management scenario in a post earthquake
situation in major cities of Bangladesh. In 2005, a nine storied garment
factory building at Savar (located about 30 km from downtown) suddenly
collapsed due to gravity load. In this incident, about one hundred workers
were killed. It took more than a month to clean the debris from the site eventhough this building is located in relatively open space compared to otherlocations and structures in Dhaka city. In February 2006, a five storiedbuilding undergoing reconstruction/renovation collapsed without warning at
the Tejgaon industrial area of Dhaka city, killing about 20 people. It isreported that this building was being built as a 500 bed specialized hospitalin joint collaboration with Mount Elizabeth Hospital, Singapore. Cleaningof the concrete debris took a few days. These are examples of vulnerable
buildings that have failed under normal loading. It is quite obvious that in
the event of a moderate to severe earthquake, many buildings face asignificant risk of collapse as a result of poor quality of construction and due
to design without seismic considerations. In densely populated areas of thecities, buildings are located on narrow roads, where it is difficult for firefighting and rescue operation vehicles to enter and operate. In addition to
inadequate road network, Bangladesh lacks necessary logistic support for
rescue and recovery operations. In other words, post earthquake disastermanagement task for Dhaka and other cities is difficult and cumbersome. A
country wide rational structural health assessment is necessary for possible
rehabilitation of critically important structures including bridges. The strict
enforcement of national building code for the new buildings as well as astrong structural assessment and rehabilitation program for the existing ones
with adequate logistic support may help to reduce the extent of devastation
during an event of earthquake. From this realization among professionals
and academics of this country, and to reduce the risk posed by seismic andman-made hazards, strengthening structural health assessment methods in
Bangladesh is evolved.

2. STRUCTURAL HEALTH ASSESSMENT METHODS
Various methods for condition assessment of civil structures are developed.
In broader sense, these methods can be categorized into two distinct groups
such as Global method and Local method. In Global method the conditionof a structure (building, bridge) is evaluated from its global response. On theother hand, in a Local method structure’s condition is evaluated based onsome of its local response at the critical locations. Brief description of the474

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methods, which are also known as Non-Destructive Evaluation (NDE)
techniques under these two broad categories are presented in the following.
2.1

Global Methods

Global methods are based on changes in their measured dynamic
properties such as the stiffness and flexibility measurement, resonancefrequency measurement, mode shape measurement or wave velocity
measurement of the structure during its vibration. Flexibility and Stiffnessof a damaged structure will be different from the good one. Thus inflexibility and stiffness method, displacement at the top of the structure
relative to its base (building, long span bridge) or drift ratio of tall buildings
is measured during a natural event (earthquake, wind loads), or a man-madeevent (blasts) using GPS technology. For this purpose, differential Global
Positioning Systems (GPS) units are placed at selected locations of thestructure (Celebi and Sanli, 2002). The drift ratio can be computed from themeasured displacement and story height. Since the drift ratio is related todamage condition of a building, this parameter is employed in an
appropriate structural analysis program to predict the stiffness of thestructure and its damage level. In this technique, as a reference, drifts forseveral pre-selected stages of damage are computed using the parametersuch as connection types, story height. Measured drift ratios are comparedwith the pre-computed drift ratios to assess the damage condition of thebuilding. Depending on the damage condition, the building can be alerted byred, yellow or green signals for the users.
GPS technology is also used to monitor the resonance frequency of
civil structures that varies when the structure is damaged because of thechange in the structural stiffness. In this method, monitoring the resonancefrequency of a building or a bridge, the condition of the structure is assessedfrom the shift in its resonance frequency. The time histories recorded dataof different GPS units placed on the roof of a building is used in the spectral
analysis to determine peak frequency (Celebi, 2005). The peak frequency
shifts when the building is damaged from earthquakes or other events.
In wave propagation method, the condition of a multi-story building isassessed by monitoring the speed of the elastic wave propagating from thebottom to the top of the building (Safak, 1999). For example, accelerometerdata were recorded at different floors of the 34 story building in San
Francisco during December 2003 San Simeon, California ealrthquake (Mw= 6.4 with epicentral distance of 258 km). Time shift of a particular peak of
the time history curve from lower floors to upper floors was measured fromthose accelerograms to obtain the velocity of the wave propagating from theground floor to the top through the building structure. It was observed thatthe wave propagated from the bottom to the top of the building (80 m high)in 0.5 seconds. This indicates that the wave velocity is 160 m/s (Celebi,2005). A lower wave velocity will be found if cracks are developed in thebuilding.

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2.2

Local Methods

In Local methods, damage condition of critical regions of a structure
is assessed by different local techniques based on visual inspection,
ultrasonic waves, acoustic emission, electric field, magnetic flux etc.
propagation. Among the local methods, Visual inspection is the oldest
nondestructive testing method which is fast, simple and economic. Many
industries opined that 80 percent of the defects found are located by visualinspection (Bray and McBride, 1992). But a large degree of uncertainty may
be associated with the visual inspection technique as small external defects
and internal defects cannot be identified by this technique.
Ultrasonic Testing (UT) based on ultrasonic waves are vibrational
waves having frequencies usually in the mega hertzs range. However, thefrequency generally varies from 50 kHz to 20 MHz when detecting most of
the defects. These techniques can be used for both the internal flaw
detection and the material characterization (Kundu, 2004b). UT can detect
defects oriented both in the plane of and normal to the surface of structuralcomponents using normal beam or angle beam transducers. By suitable
design of ultrasonic transducer, ultrasonic beams can be introduced into amaterial at almost any angle. There are several forms of ultrasonic waves,the most widely used in NDT being compressional (longitudinal) andtransverse (shear) waves. One of advantage of using this method is that forstructural element with both surfaces not accessible can also be assessed. In
the recent, component with complex geometries are assessed using
ultrasonic inspection technique based on guided waves (Lamb waves,Rayleigh waves and cylindrical guided waves). They are different from thebulk ultrasonic waves in that they continue to interact with the boundary of
the material in which they travel and require these boundaries to exist. The
boundaries confine the waves and allow them to propagate over long
distances, which make them attractive for rapid, long screening of different
systems. Guided wave ultrasonic inspection as a quality tool has become
quite popular and effective in thickness measurement, flaw detection, andmaterial characterization. The guided wave ultrasonics are very effective at
detecting anomalies along the sound path. The applications of Guided
waves have been shown for inspecting composite-concrete interface (Kundu
et al. 1999), pipes (Guo and Kundu, 2000, 2001), concrete beams (Jung et al.
2001, 2002) and interface of concrete and reinforcing bars (Na et al. 2002,
2003).
Eddy Current Method is based on electric field (Figure 1) as
developed when an alternating electric current (ac) flows in a coil of manyturns of fine. As shown in Figure 1, eddy currents are induced in thematerial due to placement of an energized coil near the surface of aconducting material that flows in a direction opposite to the current in thecoil. Eddy currents are proportional to the electrical conductivity of thematerial. Magnitude and phase of the induced current depends on thematerial properties as well as on damage (cracks and voids). Thus analyzing
the eddy currents the material conditions of a structure can be assessed. The
main advantage of this method is that mechanical contact is not required

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between the eddy current transducers and the test object. The otheradvantage is that eddy current penetration depth can be controlled byadjusting the frequency of energizing current. The penetration depth (mm),α which is related to the material resistivity (micro-ohm-cm), ρ, relative
permeability (dimensionless), μ and frequency (Hz), f is given as follow(Bray and McBride, 1992),

Eddy Current Probe
Magnetic Force Lines
Alternating
Voltage
SourceConducting
Material

Figure 1: Schematic of an eddy current probe placed near an electricallyconductive material.
1⎛ ρ ⎞2
α = 50.3⎜⎜ ⎟⎟⎝ μf ⎠(1)

For most applications, instrumentation for eddy current testing isrelatively low cost. However, the application of this technique is limited tothe electrically conductive materials only.
Acoustic Emission (AE) monitoring is a passive technique where
sensors (transducers) are mounted to listen acoustic energy released whencracks are formed inside a material. Acoustic energy is released because of
the relaxation of the stress at the point of cracks which propagates throughthe material to its surface. The source of these emissions in metals is closely
associated with the dislocation movement accompanying plastic
deformation and with the initiation and extension of cracks in a structure
under stress. The AE technique as shown in Figure 2 is based on thedetection and conversion of high frequency elastic waves emanating from

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December 2007, Dhaka, Bangladesh

the source to electrical signals. This is accomplished by directly coupling
piezoelectric transducers on the surface of the structure under test andloading the structure. The output of the piezoelectric sensors (during
stimulus) is amplified through a low-noise preamplifier, filtered to remove
any extraneous noise and further processed by suitable electronics The
mounted transducers can identify the formation or propagation of cracks
inside the material.

Figure 2: Acoustic emission (AE) testing Sensor
The acoustic emission is also generated due to dislocation movements,
fracture of brittle inclusions or surface films, fiber breakage and fiber
delamination in composite materials, melting, phase transformation, thermal
stresses, cool down cracking and stress build up. Thus one can predict thetype of damage created using this technique (Mal et al., 2003). The energyof these disturbances is termed as emission energy. The emission energy insome cases is very small and results in motion of small dislocations inmetals. During earthquakes, such emission energy is so large that theresulting disturbances cause major cracking of structurural members withconsequent catastropic collapse. The limitation of this method is that it can
detect a growing crack and size cannot be determined. The primaryadvantage of this technique is that no equipment is required to excite a pulse,and hence the instrumentation is relatively simple and inexpensive. Other
advantages are that the sensors can be located at remote locations for theobject operating in hostile environments and a relatively large volume ofmaterial can be inspected at a reasonable cost. Since in most materials, thenumber and intensity of the released acoustic signal increases significantly
near the failure point, AE technique can serve as a good warning tool before
the failure. The AE technique has been sucessfully used to detect leaks instorage tanks located above the ground (Miller, 1990; Nordstrom, 1990).
This technique has also been applied to monitor crack initiation andpropagation inn airplanes during its fligh (Martin, 1980).
The magnetic flux leakage (MFL) is one of the most widely usedtechniques to nondestructively inspect ferromagnetic materials like steel forsurface and near-surface defects (Halmshaw, 1987; ASM International,
1989). A magnetic field is applied to steel to magnetically saturate it, so thatit can't hold any additional field. In the presence of a flaw, some of themagnetic flux escapes or "leaks" into the surrounding environment, where

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magnetic sensors like Hall probes detect it and report a flaw signal. The
MFL devices rely on magnetic field perturbation created by imperfections
as the means of detecting the anomalies. The distortion in the flux field
induces an electric current in one or more groups of coils or detectors
located between the poles of the magnet and arrayed around thecircumference of the pipe. The resulting electrical signal and its location
along the pipeline are recorded on magnetic tape for analysis. MFL is mostcommonly used for inspecting lifeline structures such as oil and gas
pipelines. Magnetic flux leakage method is widely used in industrial
inspection. Typical applications of MFL include testing of longitudinalwelds in pipe during fabrication, testing of oil-field equipment including oilwell drill pipe, tubing, line pipe and structures. Pipelines are regularly
inspected for thin wall using the magnetic flux leakage principle. Internal
inspection devices called pigs as shown in Figure 3 are used for inspecting
buried pipelines. The structures and piping in chemical plants and petroleum
refineries are also tested using this technique.

Figure 3: Magnetic Flux Leakage Tests.

3. DEVELOPMENT PLAN FOR CAPACITY UPGRADING:
3.1

Institutional Strengthening

The civil engineering departments of the technical universities ofBangladesh, particularly BUET participate in a large number of national
projects yearly where it provides the necessary advisory, consultancy andtesting services to the construction industries. Some of those research-cum
consultancy projects include structural health assessment, seismic
vulnerability evaluation of critical buildings like hospitals and commercial
buildings. However at present very primitive methods (such as Schmidt
Hammer, core cutting and testing) of evaluation are used due to lack ofnecessary know-how and logistic facilities, except the recently assessed
BUET campus buildings by NDTs (BNUS Report, 2006). To reduce the riskof possible structural collapses in infrastructure, institutional strengthening
is essential for providing quality education on structural health assessment
techniques to the students and for upgrading knowledge of academics. In
this connection, some linkage or collaborative projects need to be

Structural Health Assessment of Infrastructure: The Bangladesh Perspective479

December 2007, Dhaka, Bangladesh

implemented through which our curriculum can be upgraded including
procurement of health assessment devices. In addition various training
modules can be developed for the practitioners who will be involved inhealth monitoring of buildings, bridges etc. These linkage projects may also
include the provision to provide training to the staff and masons of theconstruction industries, which is very important for quality and proper
construction. Moreover through these projects, young faculty members of
the universities can obtain their higher education (MS, PhD) in Non
Destructive Evaluation (NDE) of Infrastructures. The financial support fortechnology transfer on structural health evaluation technologies for the
infrastructure can be sought from donors under the framework ofInternational cooperation between Higher Education Institutions.
3.2

Regional Assessment and Rehabilitation Program

The Ministry of Housing and Public works, Ministry of Disaster
Management and Relief and other concerned Ministries in joint
collaboration with technical universities like BUET should start a step bystep structural health assessment program targeting specific regions
throughout the country. In this regard, the concerned Ministry can takenecessary steps to seek adequate support from international development
partners. In the assessment and rehabilitation program, priority should begiven in the educational institutions, starting from primary schools touniversities as these institution buildings are used as emergency shelters
during any disaster e.g., cyclone and earthquake. On the other hand public
hospitals of Seismic Zones 2 and 3 of Bangladesh including the buildings
where private hospitals, clinics and diagnostics centers are located should betaken care of under the framework of nation-wide assessment andrehabilitation program. Government of Bangladesh should also takenecessary steps to execute an investigation regarding the vulnerability of thecountry’s critical facilities like sea port, rail road network, electricity
generation and supply systems, gas field and their transmission systems,
telecommunication systems, etc.
In addition to above targeted infrastructures and critical facilities of
the country, the city government with joint collaboration of the Ministry of
Housing and Public could start a seismic assessment program and suggest
affordable retrofitting of vulnerable houses. The results of the seismic
assessment should be published in pictorial form in the daily newspaper sothat house and commercial building owners and the tenants can understandthe level of earthquake vulnerability of their respective structures. In thisway a fruitful awareness could be developed among the owners and tenants,
which in turn would encourage them to undertake appropriate rehabilitation
scheme to protect their assets and lives from earthquake disaster

4. CONCLUSIONSIn recent time structural collapse of buildings have occurred in Bangladesh
either as a result of seismic activity or due to inadequate ability of the480

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structures to support occupancy or wind related loads. In both cases theprimary reason for such collapse or damage was inadequate design or faulty
and poor quality of construction. Appropriate preventive steps such as
retrofitting, redesign and partial reconstruction or demolition could havesaved life and/or property. For this a thorough structural health assessmentof selected or critical structures and utility facilities is necessary. This paper
has summarized some of the structural health assessment methods as well as
their advantages, limitations and their possible applicability for structures in
Bangladesh. A more thorough analysis and comparison of various structural
health assessment methods including cost benefit analysis needs to be donein the future. In this regard it is imperative for international and multinational institutions and organizations to fund extensive research and studyof such methods.
ACKNOWLEDGEMENT
The first three authors of this paper express their gratitude to Professor
Tribikram Kundu of Civil Engineering and Engineering Mechanics
Department of The University of Arizona, USA for his kind consent to be a
co-author of this paper.

REFERENCES
ASM International, 1989. Metals Handbook, Vol. 17, 9th ed., ASM
International, Materials Park, Ohio
BNUS Report, 2006, Evaluation of the Seismic Vulverability of Bangaldesi
Buildings using Non-Destructive Testing - Microtremor
Measurements and Fefforscan, ed. Russel et al. and Yoshimura et al.,
ICUS, University of Tokyo
Bray, D. E. and D. McBride, 1992. Nondestructive Testing Techniques, John
Wiley & Sons, Inc., New York
Celebi, M., 2005. Real-time Seismic Monitoring and Functionality
Assessment of a Building, Health Monitoring and Smart
Nondestructive Evaluation of Structural and Biological Systems, IV,
Proc. of SPIE, Ed. T. Kundu, Vol. 5768, pp. 63-73.
Celebi, M., and A. Sanli, 2002. GPS in Pioneering Dynamic Monitoring ofLong Period Structures, Earthquake Spectra, Journal of EERI, Vol. 18,
No. 1, pp. 47-61
Guo, D. and T. Kundu, 2000. A New Sensor for Pipe Inspection by Lamb
Waves”, Materials Evaluation, Vol.58(8), pp.991-994
Guo, D., and T. Kundu, 2001. A New Transducer Holder Mechanism for
Pipe Inspection, Journal of the Acoustical Society of America,
Vol.110, pp.303-309
Halmshaw, R., 1987. Non-destructive Testing, Edward Arnold, London
Jung, Y. -C., T. Kundu and M. R. Ehsani, 2002. A New Nondestructive
Inspection Technique for Reinforced Concrete Beams, ACI Materials
Journal, Vol.99(3), pp.292-299
Jung, Y.C., T. Kundu and M. Ehsani, 2001. Internal Discontinuity Detectionin Concrete by Lamb Waves, Materials Evaluation, Vol.59(3), pp.418-

Structural Health Assessment of Infrastructure: The Bangladesh Perspective481

December 2007, Dhaka, Bangladesh

423
Kundu, T., 2004b. Ultrasonic Nondestructive Evaluation: Engineering and
Biological Material Characterization, Pub.CRC Press, ISBN 0-84931462-3
Kundu, T., M. Ehsani, K. I. Maslov and D. Guo, 1999. C-Scan and L-Scan
Generated Images of the Concrete/GFRP Composite Interface,
NDT&E International, Vol.32, pp.61-69
Mal, A. K., F. J. Shih and W. H. Prosser, 2003. Ultrasonic Methods forMaterial Characterization, Special Issue of I2M (Instrumentation,
Measurement and Metrology), ed. T. Kundu, Pub. Lavoisier, Paris,
Vol. 3,
p. 11
Martin, G. C. , 1980. In-Flight Acoustic Emission Monitoring, in Conf. Proc.
Mechanics of Nondestructive Testing, Blacksburg, VA.
Miller, R. K., 1990. Materials Evaluation, Vol. 48, p. 822, 826, 829
Na, W. B., T. Kundu and M. Ehsani, 2003. A Comparison of Steel-Concreteand GFRP-Concrete Interface Inspection by Guided Waves, Materials
Evaluation, Vol.61(2), pp.155-161
Na, W.B., T. Kundu and M. Ehsani, 2003. Lamb Waves for Detecting
Delamination between Steel Bars and Concrete, Computer-Aided
Civil and Infrastructure Engineering, Vol.18,pp.57-62
Na, W.B., T. Kundu and M. Ehsani, 2002. Ultrasonic Guided Waves for
Steel Bar-Concrete Interface Testing, Materials Evaluation, Vol.60(3),pp.437-444
Safak, E., 1999. Wave Propagation Formulation of Seismic Response ofMultistory Buildings, ASCE Journal of Structural Engineering, Vol.
125, No. 4, pp. 426-437

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INVESTIGATION FOR PROMOTINGSEISMIC RETROFIT OF CRITICALFACILITIES- A CASE STUDY OF WAKAYAMA CITYREIKO AMANO1 TAKEYUKI EBI2, SHOGO HAYASHI3,KIMIRO MEGURO4 KOUJI UEMATSU5, KAZUHISA FUJITA6
1Former Visiting Professor of IIS, University of Tokyo
Kajima Corporation, Tokyo, Japan
2
Kajima Corporation3
Formaer International Center for Urban Safety engineering (ICUS),
Institute of Industrial Science, University of Tokyo, Japna
4International Center for Urban Safety Engineering (ICUS),
Insititute of Industrial Sicence, University of Tokyo, Japan
5
Wakayama city, Japan
6
Fire and Disaster Management Agency (FDMA) of Ministry of Internal
Affairs and Communications, Japan
amanor@kajima.com
ABSTRACT
There has recently been active interest in municipalities in developing
hazard maps of earthquakes, tsunamis, floods, etc. However, the focus ofmany of these maps is to improve public awareness of these hazards. Thus,
maps focusing on other uses are being sought. This report introduces anexample in which a data package has been prepared by utilizing anearthquake hazard map to support investigations for prioritizing district
disaster-prevention bases for earthquake-resistant conversions.
1. INTRODUCTION
Many large earthquakes are expected to occur in Japan in the future, andrelevant authorities of the national government, municipalities, privatecompanies, etc. have planned and executed various measures to minimize
damage. Prior measures are considered to be more effective in mitigating
the impact of earthquake disasters than post-disaster measures. In particular,
it has been reported that the most effective method is to strengthen buildings
and structures to make them earthquake resistant (Meguro, 2006). However,
it is not easy for municipalities with limited budgets to strengthen their
many facilities. As a result, action has been delayed even for disasterprevention bases.
The paper “Materials for promoting earthquake-resistant strengtheningof disaster-prevention bases” was circulated in 2005 for the use of in-charge
persons in municipalities. In 2006, this was used as a basis for aninvestigation aimed at promoting seismic retrofit of disaster-prevention
bases in Wakayama city. Damage is anticipated in Wakayama city from483

December 2007, Dhaka, Bangladesh

future potential Tonankai and Nankai Earthquakes. The investigation was
aimed at prioritizing Wakayama city’s many disaster-prevention bases
taking into account the structures and earthquake hazard.
This investigation was carried out as an Industry-GovernmentEducation joint project as a continuation from 2005, and was led by theauthor and her co-workers from Ministry of Internal Affairs andCommunications and ICUS, IIS, University of Tokyo.
2. OVERVIEW OF WAKAYAMA CITY
Wakayama city, capital of Wakayama prefecture, is located in the northwestern part of the Kii Peninsula, near the border with Osaka-fu. It faces
the Izumi Mountains to the north and the Kitan Strait to the west. Figure 1
shows the location map of the city.
The city extends to the mouth of the Kinokawa River, registered as afirst-class river in Japan. The coastal area and area along the KinokawaRiver are lowlands. The city covers an area of 210km2 and its population isabout 376,000 as of October 1, 2006, showing a decreasing tendency fromits peak of about 403,000 in 1982.

Kansai Airport

Wakayama city

Figure 1: Location map of Wakayama city
3. EARTHQUAKE IN WAKAYAMA CITY
3.1

Past earthquake damage

The observed earthquake occurrence distribution in Wakayama cityand its environs is shown in Figure 3-1. Many large and small earthquakes

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have been observed in Wakayama prefecture and in neighboring waters,
showing that it is a very earthquake-prone area.
During their history, the Kinki and Shikoku regions have experienced
many large earthquakes. Including tsunami damage accompanied some ofthese earthquakes, past records show that several thousand to several tens of
thousands of casualties occurred in earthquakes of 1707 Hoei (M8.4), 1854
Ansei Nankai (M8.4), 1944 Tonankai (M7.9), 1946 Nankai-do-oki (M8.0),
etc.

Magnitude

Figure 2: Epicenter distribution in Wakayama city and surroundings(New SEIRA output)
3.2

Future anticipated earthquakes

In 2005, as an aid in development of a future regional disasterprevention plan, Wakayama city conducted an investigation to predict
damage caused by two anticipated classes of earthquakes. The first includes
the “Tokai, Tonankai and Nankai Earthquakes,” and these are being
investigated by the governmental Central Disaster Prevention Conference.
The other is the “Chuo Kozo-sen (Central Tectonic Fault)” induced
earthquake. This tectonic fault runs directly below Wakayama city. The
predicted damage due to these two classes of earthquakes is outlined inTable 1.

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Table 3-1: Outline of assumed earthquakes in Wakayama city
Simultaneous occurrence Central Tectonic Lineof Takai, Tonankai and Earthquake
Nankai Earthquakes
Earthquake size
M 8.6 equivalent
M 8.0 equivalent
Locationof Suruga trough – Nankai Central Tectonic Linehypocenter fault
trough(Awaji Island
southeasternmost – near Izumi
Mountains easternmost
Depth
of About 10 – 30km
4 – 14km
hypocenter fault
Seismic intensity A little over 6 – a little 7 – a little below 6
blow 5
Liquefaction
High hazard mainly for High hazard for valley
filled up land and plain area in mountains inarea
addition to filled up landand plain area
Steep
slope 72 locations
311 locations/Mountainsideslide
TsunamiMaximum tsunami height Tsunami does not occur
when it hits
1.05 – 3.89m
Building collapse Total
collapse
4,071 Total collapse 33,483
buildings
buildings
Casualties (as of 2,659 persons
9,094 persons
18:00
hrs
in
winter)Peopleof 36,834 persons
201,334 persons
temporarily
restricted housing(as of 18:00 hrs in
winter)Damaged water 135 locations
1,305 locations
works
Probabilityof Nankai
Earthquake 0 – 5%earthquake
about50%
occurrence
for Tonankai
Earthquake
coming 30 years
about 60 – 70%486

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Tokai
TonankaiNankaiFigure 3: Assumed hypocentral region map of Tokai, Tonankai and Nankai
Earthquake

Hypocenter (Failure
onset point)

Osaka bay

Central Tectonic
Li
Awaji Island

Wakayama city

Figure 4: Assumed hypocentral region map of Central Tectonic Fault
Earthquake
4. INVESTIGATIONTOPRIORITIZE
FACILITIESDISASTER-PREVENTION BASES FOR SEISMIC RETROFITOF

In order to implement seismic retrofit of facilities of disaster-prevention
bases, it was necessary to first carry out a seismic diagnosis of them and toassess their health. However, a large budget and a lot of time would havebeen necessary for detailed seismic diagnosis. Furthermore, it was difficult
for Wakayama city to carry out the diagnosis of all of its many facilities atthe same time. Thus, for budget phasing, it was necessary to determine
priorities that would enable the city to carry out detailed seismic diagnoses
in a phased manner over a period of years. It was therefore decided toproceed with the investigation according to the flow chart shown in figure 5.

Investigation for Promoting Seismic Retrofit of Critical Facilities - A Case Study of Wakayama City-

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December 2007, Dhaka, Bangladesh

Indentify disaster prevention Bases
Implement “Quick Scismic
Diagnosis”

Define scenario earthquake
Investigate predcted damage
due to sccnarioearthquake

Investigate prioritizing method by detailed seismic diagnosis
Results of investigation and analyses

District conditions
District budget

Current study’s boundary

Implement seismic diagnosis for municipal facilities as disasterprevention bases and prepare earthquake resistant repair plan

Correct district disasterprevention plan
Prepare action plan

Secure budget for seismic diagnosis /reinforcement
Strengthen disaster-prevention
facilities

Figure 5: Investigation flow
4.1

Implement quick seismic diagnosis of facilities for disasterprevention bases

4.1.1 Identify facilities for disaster-prevention bases
A seismic retrofit project was already in progress for schools, etc. in
Wakayama city that were planned for use mainly as shelters. In addition,
165 of Wakayama city’s facilities for disaster-prevention bases wereidentified where seismic diagnosis was considered necessary. Therefacilities are shown in Figure 6.

(Liaison Office)(Fire Station)(Pump Station)

Figure 6: Part of facilities of disaster-prevention bases in Wakayama city

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4.1.2 Implement questionnaire-type “Quick Seismic Diagnosis” (Kajima,
2005)
Quick seismic diagnosis has been developed as a useful tool, based on
the results of many detailed seismic diagnoses. A simple questionnaire
consisting of 26 questions was prepared. These questions would be easy toanswer by persons involved in the building industry, and the results would
assist in development of a simplified seismic diagnosis. However, it was
not practical for the questionnaire to be answered by only ICUS engineers
for all 165 facilities to be used for disaster-prevention bases over the wholearea of Wakayama city. Thus, a training course for “Quick Seismic
Diagnosis” was held to instruct people how to fill in the questionnaire. Thiswas carried out with the participation of about 25 building engineers of
Wakayama city who were familiar with local conditions. These engineers
then carried out a site survey of the relevant facilities for about one month,and then answered the questionnaire.
The main contents of thequestionnaire were as follows:• What is the number of stories and the total floor area?
• What year was construction of the facility commenced andcompleted?
• What is the structural type?・Does the facility have pilotis?
• What is the plan configuration of the facility?
• What is the size of the facility’s walls and windows?
• What are the soil conditions at and surrounding the site?
Many of the questions could be simply answered from preset answer
options with the help of easy-to-understand figures.
The building engineers of Wakayama city were also requested toattach photos of the facilities with their answers. If they were unsure aboutsome of the questions, ICUS engineers clarified their answers using theprovided photos to increase diagnosis accuracy.

Figure 7:

Questionnaire for “Quick Seismic Diagnosis”(part of it)

Investigation for Promoting Seismic Retrofit of Critical Facilities - A Case Study of Wakayama City-

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December 2007, Dhaka, Bangladesh

Figure 8: Training course for “Quick Seismic Diagnosis”
The analysis results for the 165 facilities were assessed as five gradeswith six indices, i.e. site conditions, building plan configuration, building
elevation configuration, seismic standard compliance, deterioration
conditions and overall assessment. In addition, the cost of the seismic
retrofit for each building was roughly estimated on the basis of similarbuildings. The estimated cost covered the cumulative reinforcement cost
necessary for the building to satisfy the standard required earthquake
resistance defined by the current Construction Standard Act of Japan.

Figure 9: Example of Quick Seismic Diagnosis results
4.2

Investigation of predicted damage

As stated in Section 3 above, two potential classes of earthquakes
were identified: the Tokai, Tonankai and Nankai Earthquakes and theCentral Tectonic Fault Earthquake. For the scenario-based investigation onprioritizing the facilities for detailed seismic diagnosis, it was necessary to
select one of these two earthquake classes. The Central Tectonic Fault
Earthquake, whose epicenter is directly below Wakayama city, would cause
huge damage but its occurrence probability in the coming 30 years is only 0
to 5%. However, the occurrence probability of the Tokai, Tonankai andNankai Earthquakes is 50 to 70%. As a result of discussions with therelevant authorities, it was agreed that predicted damage due to thepresumed Tokai, Tonankai and Nakai Earthquake would be the priority forthe investigation. Then, taking into account the longevity of the facilities

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used for disaster-prevention bases and phasing of the budget, it was decided
to investigate the subject priority using the above predicted damage.
The utilized predicted damage was based on GIS, and data wereextracted by ICUS. The GIS was prepared by Wakayama city as shown in
the “Report on results of investigation on predicted earthquake damage ascontracted work to develop hazard maps for Wakayama city, etc. (March
2005)” (hereinafter called “Report on predicted damage for Wakayama
city”).
4.3 Investigation of prioritization method for detailed seismic
diagnosis
4.3.1 Categorization roles of disaster-prevention bases
The roles of the disaster-prevention bases in the event of a disastervary. For example, in Wakayama city, “Fire Station” takes the roles ofcontrolling / executing measures, dispatching / gathering information,
helping / rescuing, etc. “Health Center” takes the roles of dispatching /gathering information and conducting temporary recovery. “Shelter” is aplace of refuge for disaster victims. Furthermore, “Branch / Liaison Office”
and “Stockpile Storehouse” have their respective roles. However, no roles
had been allocated to the 165 facilities for disaster-prevention bases.
Prioritization is not practical if the roles are treated equally. As a result, 61of the 165 facilities that must perform one or more key roles in the event of
a disaster were selected for the current investigation. They were identified
as “Critical Facilities in Disaster Mode” (key roles are A: control / executemeasures, B: dispatch / gather information, C: help / rescue and D:
temporary recovery). It is noted that these 61 facilities included those where
seismic retrofit was already progressing. This was due to the need to clarify
these facilities’ placement conditions to cover the whole district and toassess their resistance to damage.
Table 2: Roles of disaster-prevention bases in Wakayama city
Disaster prevention Fire
City hall Branchbases (roles)
station/liaison/office
officeHealthcenterA

Control andmeasuresexecute

○

○

○

B

○

○

○

○

C

Dispatch and gather
information
help and rescue

D

temporary recovery

○

○

○

E

Human

F

G1
G2

Material○

VictimInjuredShelter – Shelter – Stockpile
storehousschool otherethanschool○○26
locations:emergency
medicalorganizati
ons

○

Food

○

○

Others○○Investigation for Promoting Seismic Retrofit of Critical Facilities - A Case Study of Wakayama City-

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December 2007, Dhaka, Bangladesh
Disaster prevention Fire
City hall Branchbases (roles)
station/liaison/office
officeLifeline

HealthcenterShelter – Shelter – Stockpile
school otherstorehousthaneschoolElectricity
Water

4.3.2 Kinds of hazards
Many data were incorporated into GIS during the work to produce the“Report on predicted damage for Wakayama city”. These data included not
only natural and social conditions but also predicted natural phenomena anda variety of predicted damage to facilities and people. The current
investigation predicted direct damage to structures of disaster-prevention
base facilities by measuring the severity of hazards predicted to be causedby the presumed Tokai, Tonankai and Nankai Earthquakes. Specifically,
three kinds of hazards were studied: seismic intensity, tsunami and landslide.
These were supplemented by liquefaction potential values.
4.3.3 Assessment Method
Facilities exposed to large hazards of tsunami or landslide disasterwere excluded from the facilities of interest for the current prioritization
investigation. This is because they would fail to fulfill their roles as
disaster-prevention bases even if their earthquake resistance were improved.
It is desirable to study these facilities separately when considering measures
for mitigating the impact of hazards or avoiding hazards as well as theapplication of seismic retrofit.
For facilities of interest, the seismic hazard Z of each facility was
obtained from the earthquake ground motion and “overall assessment scoreX”, and priority was determined on that basis.
The specific assessment procedures were as follows:
1. Extract numerical data of seismic intensity, tsunami, landslidedisaster and liquefaction at the locations of the 61 disasterprevention base facilities of interest using GIS data obtained fromthe “Report on predicted damage for Wakayama city”.
2. Exclude facilities exposed to large hazard of tsunami or landslidedisaster from facilities of interest. Add supplementary notes onliquefaction for reference only.
3. Derive correction factor α from seismic intensity at each facility
location. Assess earthquake resistance taking into account external
force or earthquake ground motion. However, seismic intensity is
not equal to external force. Thus, acceleration correlatable toseismic intensity was introduced. Acceleration corresponding toseismic intensity slightly below 6 (reference number) was defined as
reference acceleration. It is noted that buildings must be resistant toseismic intensity slightly less than 6, according to the current
Construction Standard Act of Japan. Then, the ratio of the492

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acceleration corresponding to each scenario seismic intensity to thereference acceleration was defined as correction factor α.
4. Obtain seismic hazard Z by dividing correction factor α by overall
assessment score X from “Quick Seismic Diagnosis”.
Seismic hazard Z =α / X
5. Give priority in order from large seismic hazard Z obtained above tosmaller (the larger the number, the higher the priority).
Table 3: Estimate of correction factor α (relationship between seismic
intensity and corresponding acceleration)
Seismic
scale

intensity Scenario Corresponding
Correction
2
seismic acceleration cm/s factor α *2)intensity
A little below 5
4.5
80.0
0.23
4.6
94.0
0.27
4.7
108.0
0.31
4.8
122.0
0.35
4.9
136.0
0.39
Slightly over 5
5.0
150.0
0.43
5.1
174.0
0.50
5.2
198.0
0.57
5.3
222.0
0.63
5.4
246.0
0.70
Slightly under 6
5.5
270.0
0.77
5.6
310.2
0.89
5.7
350.4
1.00
Reference
number *1)
5.8
390.6
1.11
5.9
430.8
1.23
Slightly over 6
6.0
480.0
1.37
6.1
554.0
1.58
6.2
628.0
1.79
6.3
702.0
2.00
6.4
776.0
2.21
7
6.5
850.0850.0
2.43* 1) Reference seismic intensity was defined to be mid-point ofseismic intensity scale of “slightly under 6”, which is the current
standard earthquake resistance requirement, thus to be 5.7* 2) Correction factor was defined to be the ratio of the acceleration
corresponding to a certain scenario seismic intensity to thereference acceleration 350.4 cm/s2 corresponding to the reference
seismic intensity 5.7.
4.4

Results of investigation and analysis

4.4.1 Overlay on hazard maps
GIS output and locations / names of facilities of interest are shown in
Figures 10. They enabled us to identify the distribution of facilities andInvestigation for Promoting Seismic Retrofit of Critical Facilities - A Case Study of Wakayama City-

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December 2007, Dhaka, Bangladesh

hazards.They should also be useful for subsequent work in developing anaction plan, etc.
4.4.2 Results of investigations on priorities of critical facilities in disaster
mode
Table 4 shows part of the results of the investigations on priorities ofcritical facilities in disaster mode, assuming the Tokai, Tonankai andNankai Earthquakes. No facilities were found where a landslide disaster
was anticipated (denoted by “0” in Table 4). Two facilities were foundwhere a tsunami was anticipated (M fire station and T branch office). The
other 59 facilities were sorted in order from larger seismic hazard to lower.
In addition, the cost of a detailed seismic diagnosis for each facility
was estimated based on similar size and type of buildings.
It is noted that the facilities where questionnaire type “Quick Seismic
Diagnosis” was not applied were regarded as no-diagnosis-needed facilities.
They were evenly assessed as having an overall assessment score X of 3.5*).
(* Overall assessment score X = 5.0, 4.5 and 4.0 corresponds to avibration isolation building, a vibration controlled building or a building
taller than 60m, and a building taller than 45m, respectively.)
Referring to the current investigation results, it was agreed to startplanning for budgeting the detailed seismic diagnosis for seismic retrofit
work, taking into account individual circumstances and in line with themunicipality budget.
Seismic

Tsuna

Landslide

LiquefFigure 10: Hazard distribution due to Tokai, Tonankai and Nankai
Earthquake and facility location map

494

New Technologies for Urban Safety of Mega Cities in Asia

5.
D F

D

山 腹
崩 壊

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

地 す
べ り

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

0

0

0

0

0

0

急 傾
斜

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

5. 5

5. 5

5. 5

5. 7

5. 7

5. 7

5. 6

5. 7

5. 7

5. 5

6. 1

5. 7

5. 2

5. 4

シ ナ リ オ
震 度 ａ

0. 00

0. 00

0. 00

0. 00

4. 9

5. 0

5. 0

5. 0

（skipped）

0. 00

0. 03

18. 63

15. 62

0. 01

19. 23

10. 43

10. 17

7. 53

18. 63

8. 43

28. 21

18. 155. 93

液 状 化 PL
値

0. 39

0. 43

0. 43

0. 43

0. 77

0. 77

0. 77

1. 00

1. 00

1. 00

0. 89

1. 00

1. 00

0. 77

1. 58

1. 00

補 正 係 数
α

3. 0

2. 5

2. 5

2. 5

2. 0

2. 0

2. 0

2. 5

2. 5

2. 5

2. 0

2. 0

2. 0

1. 5

2. 5

1. 5

2. 0

3. 5

総 合 評 価
Ｘ

0. 13

0. 17

0. 17

0. 17

0. 39

0. 39

0. 39

0. 40

0. 40

0. 40

0. 45

0. 50

0. 50

0. 51

0. 63

0. 67

耐 震 危 険
性 Ｚ

優 先 順
位

59

56

56

56

10

10

10

7

7

7

6

4

4

3

2

1

備

考
0 津 波 に よ り 対 象 外

160

160

160

160

130

170

230

170 津 波 要 注 意

160

160

160

160

160

270

160

220

150 津 波 に よ り 対 象 外

耐 震 診 断 費
( 万 円 ）

注 ）・ 山 腹 崩 壊 、 地 す べ り 、 土 石 流 、 急 傾 斜 の 値 ０ は 、 本 ハ ザ ー ド の 対 象 範 囲 外 で あ る こ と を 示 す 。
・ 耐 震 診 断 費 は 階 数 及 び 延 床 面 積 か ら 概 略 算 定 し た も の 。

0

0

0

0

0

0

0

0. 09

0

0

0

0

0

0

0

0

1. 18

0. 84

津 波 浸 水深 （ ｍ ）

Table 4-3: Results of priority investigation

土 石流

Items in top row (from left to right):
Facility No., Building Name, Role, Mountainside Slide, Landslide, Debris Flow, Steep Slope, Flood Depth by Tsunami, Liquefaction
PL, Scenario Seismic Intensity, Correction Factor α, Overall Assessment X, Seismic Hazard Z, Priority, Seismic Diagnosis Cost (\tenthousand), Remarks
Items in “Remarks” column (from top to bottom, blank skipped)
Excluded due to tsunami, Excluded due to tsunami, Beware tsunamiNote) The number 0 specified for a Mountainside Slide, Landslide, Debris Flow, Steep Slope means that they were out of thehazards of interest of the current investigation.
- Seismic diagnosis cost was roughly estimated from the number of stories and total floor area

ABC

AB

105 Ｎ Ｙ 支 所

80 Ｋ 消 防 署 Ｎ 出 張 所

ABAB

95 Ｍ 連 絡 所

AB

116 Ｚ 支 所 Ｚ 地 区 会 館

102 Ｎ Ｗ 支 所

AB

ABC

AB

AB

107 Ａ 支 所

136 Ｎ 保 健 セ ン タ ー

79 Ｍ 消 防 署 Ｍ 出 張 所

111 Ｋ 支 所

90 Ｍ 連 絡 所

ABAB

92 Ｍ 連 絡 所

117 Ｗ 支 所

AB

AB

91 Ｓ 連 絡 所

134 Ｅ 研 究 所

104 Ｙ 支 所

135 Ｍ 保 健 セ ン タ ー

D F

ABC

0 Ｍ 消 防 署
AB役 割

建 物 名 称119 Ｔ 支 所

施 設
NO

ICUS Report 27

CONCLUDING REMARKSIn this investigation, priority was determined from the hazard and theearthquake resistance of the facility. The priority assessment was based onwhether the structure was sustainable. However, criticality of a disasterprevention base should be assessed not only from the structure’s health but

Investigation for Promoting Seismic Retrofit of Critical Facilities - A Case Study of Wakayama City-

495

December 2007, Dhaka, Bangladesh

also from various factors such as accessibility, sustainability of lifelinefunction, surrounding population, wooden building ratio, etc.
If the current assessment using seismic hazard Z is regarded as asingle-axis assessment, a double-axis assessment would be envisaged asfollows. For example, if the seismic hazard Z of the shelter vs. night
population, etc. are plotted on a two-axis graph, facilities in a dense
population area but with insufficient earthquake resistance become visible.
Thus, the assessment method would vary with the facility’s role.
The current investigations could utilize “Report on predicted damage
for Wakayama city” that Wakayama city worked on in the preceding year.
However, even if damage is repeatedly predicted, it can never be reduced(Meguro, 2006). Predicted damage is not useful until it is utilized fordisaster impact mitigation measures as in the current investigation. It isplanned to further utilize current investigation results in accordance withdemand for revision of Wakayama city’s disaster prevention plan anddevelopment of an action plan.
ICUS expects to contribute to the promotion of seismic retrofit ofcritical municipal facilities by uploading the current investigation results tothe website of the FDMA (Fire and Disaster Management Agency) entitled“Materials for promoting earthquake-resistant strengthening of disasterprevention bases” and by distributing materials to the relevant authorities
through the FDMA.
The authors express their sincere appreciation to the staff of theGeneral Disaster Prevention Office of Wakayama city and to the staff ofKajima Corporation, who provided the authors with a lot of help and advice.
REFERENCES
Central Disaster Prevention Conference HP (The Cabinet Office)Kajima Corporation HP, 2005., KAJIMA Digest, September
Japan Road Association, 2002. Road and bridge specifications andexplanatory note V Seismic design version, March.
Chihokokyodantai tantosha notameno “Bosai kyoten no taishinka
sokushin shiryo” (“Materials for promoting earthquake-resistantstrengthening of disaster-prevention bases” for in-charge persons inmunicipalities) HP (FDMA)
Meguro, K., 2006. “Jishin bosaijo no saijuyo kadai dearu kison
futekikaku tatemono no taishin kaishu wo suishin suru tameni (In order toimplement earthquake resistant repair of existing inadequate buildings thatare the most critical task in earthquake disaster prevention)”Shobo Bosai
Spring Issue vol 5, No. 2
Mapion HP (Cybermap Japan)
Wakayama city HP (Wakayama city)
Ukon,
H.,
2006.
Nagata,S.,
Miyamura,M.(editors)“Risukumanejimento notameno jishin kikendo kaiseki sisutemu (Seismic496

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

hazard anaysis system for risk management)”Urban Technology Promotion
Conference, 18th Technical Research Meeting, November 9.
Wakayama city, 2005. “Jishin higai soutei chosa kekka houkokusho(Report on investigation results of earthquake damage supposition)”contracted work to develop Wakayama city tsunami hazard map, etc.,
Kokusai Kogyo KK, March.
Wakayama city, 2005. Wakayama city disaster prevention plan 2005
revsion Wakayama city disaster prevention meeting.

Investigation for Promoting Seismic Retrofit of Critical Facilities - A Case Study of Wakayama City-

497

December 2007, Dhaka, Bangladesh

498

New Technologies for Urban Safety of Mega Cities in Asia

FRAGILITY ANALYSIS OF REINFORCED
CONCRETE FRAME STRUCTURESMUNAZ A. NOOR
Bangladesh University of Engineering & Technology
mnoor@ce.buet.ac.bd
M. YASIN
Bangladesh University of Engineering & Technology
yasinbuet96@yahoo.com
ABSTRACTIn this paper fragility curves of low rise reinforced concrete frame
structures in Bangladesh is presented. The fragility analysis has been
performed using the method proposed by Bazzurro et al. (2004).
Uncertainty of three structural parameters, concrete compressive strength,
column size and concrete cover have been considered. Fragility curves ofdifferent structural limit states of a typical structure have been developed
from probabilistic seismic hazard of the site and performance of thestructures against the hazard. The uncertainty inherent in building response
and capacity for different ground motion levels due to variability inconstruction and structural evaluation process is used to obtain the desired
fragility curves. The main feature of this method is that fragility curves canbe drawn very easily.

1. INTRODUCTION
Fragility of structures is obtained from probabilistic seismic hazard of thesite and performance of structure or stock of structures against the hazard.
Fragility curves of a structure are used to predict the post earthquake
functionality. Prediction of the post-earthquake functionality of theimportant structures such as hospital building, fire brigade building anddigester shelter is essential for earthquake digester management. It is very
important to identify the vulnerable buildings and estimate the level ofdamage under a probable earthquake by combining the probabilistic seismic
hazard and fragility of the concerning structure or stock of structures.
Noor et al. (2005) developed probabilistic seismic hazard curves for
Dhaka, Chittagong and Sylhet city using Boore et al. (1993) and McGuire(1978) acceleration attenuation expression. By using other acceleration
attenuation expressions same type of seismic hazard curves with different
curvature, can be developed through same procedure, from the same
earthquake database. A complex methodology that may be followed toconstruct fragility curves for reinforced concrete (RC) frame structures in
Bangladesh is presented in Noor and Manzur (2005). In the present study
seismic hazard analysis is done by using Duggal (1989) acceleration
attenuation expression and the earthquake database prepared by Sharfuddin499

December 2007, Dhaka, Bangladesh(2001) and limit-state fragility analysis is done by following the guideline
stated in Bazzurro et al. (2004). Duggal (1989) acceleration attenuation
expression is developed for the alluvium soil of Japan. The soil of
Bangladesh is alluvium. Finally a set of fragility curves for different limit
states is prepared for a typical three storey RC frame structure.

2. METHODOLOGY
A limit-state fragility curve provides the conditional probability that the
specified limit state will be reached or exceeded as a function of the severityof the future ground motion. Fragility curves involve uncertainties
associated with dynamic displacements produced by different groundmotion records, material properties, structure geometry, structure modelingand analysis procedure. In Noor and Manzur (2005) a time consuming
methodology is used to construct fragility curves for RC frame structures in
Bangladesh. In that method a structure is needed to be analyzed many times
and the method is time consuming. In this study a structure is needed to beanalyzed three times with three percentile values for a particular parameter.
Limit-state fragility analysis is done by following the guideline stated in
Bazzurro et al. (2004) and considering uncertainty of three major structuralparameters, concrete compressive strength, column size and concrete cover.
In this research work the limit states in fragilities are related to loss ofdynamic capacity.
2.1

Pushover Analysis

For seismic assessment of structures, the knowledge of the nonlinear
static behavior of a specific structure subjected to incremental lateraldeflection is used and quadrilinear approximation is done to infer its
nonlinear dynamic response expected for different levels of ground motion
severity. Quantitative measures of the implied degradation in structure
safety is used to associate each of several post-earthquake structural damage
states with an appropriate post-earthquake structural limit state that may
imply some degree of occupancy restrictions. This method of analysis is
known as pushover analysis.
2.2

Estimation of Uncertainty

The uncertainty inherent in building response and capacity for
different ground motion levels due to variability in construction andstructural evaluation process is used to obtain the desired fragility curves forthe different structural limit states. Uncertainty is measured from percentile
values of parameters and using Equation 1 and the square-root-of-sum-ofsquares (SRSS) rule is used to combine the uncertainty (Bazzurro et al.
2004).
1 ⎛ S ⎞
⇒ β = ln⎜⎜ ( LSa ⎟⎟x ⎝ Sa ⎠500(1)

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

where,
β =uncertainty
S a = percentile spectral acceleration(
S aLS= median spectral acceleration to attain concerning limit statex = −0.67,0.0,0.67
for 25 percentile, 50 percentile and 75 percentile value respectively, othervalues of x can be obtained from table of the Gaussian distribution function.
2.3

Computation of the Fragility Curves

From the median spectral acceleration and corresponding uncertainty(β) the fragility curves associated with onset-of-damage, onset of yellow-tag,
onset red-tag, and onset collapse states are plot using Equation 2 (Bazzurro
et al. 2004).
(
S a = S aLS e xβ(2)3. DEFINING LIMIT STATES

Seismic hazard analysis of Dhaka is performed by using Duggal(1989) acceleration attenuation expression and the earthquake database
prepared by Sharfuddin (2001). Developed seismic hazard curve for Dhaka
city is shown in Figure 1.The proposed primary tagging criteria of different
limit states are obtained from seismic hazard curve of Dhaka (Figure 1) anddisplayed in graphical form in Figure 2. The values of the quantities in
Figure 2 are proposed for Dhaka city and should be reevaluated for othersites and structures of different importance.

Figure 1: Seismic Hazard Curve for Dhaka city, developed using Duggal(1989) acceleration attenuation expression

Fragility Analysis of Reinforced Concrete Frame Structures

501

December 2007, Dhaka, Bangladesh

60

10
50

RED

7

40

5

YELLOW

4

P/P05%/50yrs

30

3
20
2

2%/50yrs

GREEN
1

-5

10

-4

P0

10

Loss of Sa cap (%)

6

10

4
2
0
-3
10

Figure 2: Graphical representation of tagging criteria for Dhaka ciry
In Figure 2, P0 is building-site-specific mean annual frequency (MAF)of exceedance of the ground motion corresponding to the dynamic capacity(Ša,cap) of intact structure and P is building-site-specific MAF of theaftershock ground motion corresponding to the median capacity of thedamaged structure. Any building is identified by a particular value of P0 thatcan be computed during “peace” time before any earthquake has occurred.
A larger value of P0 implies that the building is either relatively “weak”, orthat it is located in an area of higher seismic hazard compared to thatconsidered in the original design, or a combination of both. The opposite istrue for lower values of P0.

4. FRAGILITY ANALYSIS OF A TYPICAL THREE STOREY
REINFORCED CONCRETE FRAME STRUCTURE

A typical three storey reinforced concrete frame is analyzed. The plan andelevation are shown in Figure 3. The building is designed for gravity load.
Three dimensional models are created and static displacement controlled
pushover analysis is done using Opensees1.6.2 (McKenna and Fenves,2001).
The solid line in the Figure 4 is static pushover (SPO) curve anddashed line is quadrilinear approximation (Bazzurro et al. 2004). The
damage states are identified as on the curve of Figure.4. These choices ofdamage states are not unique. Any other point relating to a change in any
structure properties can be chosen as a damage state. Later, these damage
states will be associated to different structural limit states.

502

New Technologies for Urban Safety of Mega Cities in Asia

Ctrl. Node,where
displacement
is applied.

10'

15'

10'

ICUS Report 27

10'

15'

Ctrl. Node,where
displacement
is applied.

12'

12'

PLAN

ELEVATION

Figure 3: A typical three storey reinforced concrete building frame

Figure 4: Non linear static pushover curve for the intact structure
The assessment of the residual lateral capacity of the building in adamage state is of interest provided that at the local level every damaged
structural member is still capable of carrying vertical loads. If there is lossof local member vertical capacity in the damage state the building will beassigned a structural limit state that corresponds to collapse. The pushover
curve for a structure at the onset-of-damage state (DS1 in Figure 4) coincides
with that of the intact structure. Nonlinear Static Pushover (NSP) curves forother damage states are obtained simply by assuming parallel to elastic
unloading/re-loading (Figure 5 and Figure 6) that can result in comparable
estimates of residual dynamic capacity. Unloading the structure from adamage state may create an initial offset in the damaged-structure NSP
curve due to the residual permanent displacement in the structure. The
extent of this permanent displacement is somewhat an artifact of applying astatic procedure to modeling the dynamic response of the structure subject
to ground shaking. The residual displacement obtained from the NSP can beconsidered as an upper bound because the structure is not allowed tooscillate and therefore return to a residual offset closer to its original uprightposition. The NSP curves for the structure in the damaged conditions are
assumed to start from the origin of the axes (i.e., no permanent
displacement). The effects of the expected (or measured) dynamic residual
offsets on the residual lateral capacities are accounted to infer dynamic
Fragility Analysis of Reinforced Concrete Frame Structures503

December 2007, Dhaka, Bangladesh

response. As illustrated in Figure 5, the horizontal shift of the NSP curves
for the damaged structures back to the origin does not shift the collapse (e.g.,DS4) displacement.

Figure 5: Non linear static pushover curve for damage state DS2

Figure 6: Quardrilinear approximation of DS2 NSP curve, with and without
offsetThe Incremental dynamic analysis (IDA) curves are obtained from thequardrilinear approximation of NSP curves and shown in Figure 7. For the
intact structure four structural damage states are attained at four different
spectral accelerations. The capacity of the intact structure and residual
capacity of damaged structure are obtained. Figure 8 shows the percent lossof spectral capacity (loss of dynamic capacity) at different spectral
acceleration. The input percentile values of those parameters are as in
Table 1. The static pushover curves and incremental dynamic analysis
curves obtained are shown in Figure 9.

504

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

Figure 7: Incremental Dynamic Analysis curves for the structure in different
states0.9
0.8

Spectral acceleration (g)

0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0

20

40

60

80

100

Loss of Sa capacity (percent)Figure 8: Loss of spectral acceleration capacity at different spectral
acceleration
Table 1: Percentile values of three structural parameters
Parameter
Mean value
Percentile value
4.0 ksi (mean) 50 percentile = 4.0 ksi
Concrete
25 percentile = 3.5 ksi
compressive
75 percentile = 4.5 ksi
strength
Column depth 12.00 in
50 percentile = 12.00 in
25 percentile = 11.75 in
75 percentile = 12.25 inCover
2.50 in50 percentile = 2.50 in
25 percentile = 2.25 in
75 percentile = 2.75 in

Fragility Analysis of Reinforced Concrete Frame Structures505

December 2007, Dhaka, Bangladesh(a) for three percentile values of concrete compressive strength(b) for three percentile values of column size(c) for three percentile values of concrete cover
Figure 9: Static pushover curves and incremental dynamic analysis curvesof the intact structure.
The uncertainty (β) inherent in building response and capacity for
different ground motion levels due to variability in construction andstructural evaluation process is used to obtain the desired fragility curves forthe different structural limit states. Uncertainty (β) is measured frompercentile values of parameters and using Equation 1 and the square-root-ofsum-of-squares (SRSS) rule is used to combine the uncertainty.
Computation of the Fragility Curves

From median Sa-values and corresponding β-values of four groundmotion levels, the fragility curves associated with onset-of-damage, onset ofyellow, onset red, and onset collapse states are plot using Equation 2. The
resulting fragility curves are shown in Figure 10.

506

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

Figure 10: Fragility curves for different limit states of the building
In Figure 10 fragility curve for onset of damage (OD) is the steepestof the four because the value of β is the smallest. The opposite is true for thefragility curve corresponding to the collapse state. The fragility curve
corresponding to the green-tag state is equal to unity for all levels of groundmotion.

5. CONCLUSION

A methodology is presented to predict post-earthquake functionality of astructure. Coupling the fragility curves with probabilistic seismic hazard
analysis will permit assessments of the seismic performance of structures.
The procedure developed in this research work is of more generalapplicability and can be valuable to engineers to assess seismic performanceof structure or stock of structure to predict post-earthquake functionality.

REFERENCES

Bazzurro, P., Cornell, C.A., Menun, C., Luco, N., Motahari, M., 2004.
Advanced Seismic Assessment Guidlines. Stanford University, Stanford CA,
Sep. 30, 2004.
Boore, D.M., Joyner, W.B., Fumal, T.E., 1993. Estimation of response
spectra and peak accelerations from western North America earthquakes:
An interim report, Open-File-Report 93-509, U.S. Geological Survey,
Reston, Virginia, 72 pp.
Duggal, R., 1989. Estimation of Seismic Risk and Damage, Their
Utilization as Design Criteria. M Engg. Thesis, University of Tokyo, Japan.
McGuire, R. K. 1978. Seismic Ground Motion Parameter Relations.
Journal of the Geotechnical Engineering Division, ASCE, Vol. 104, No.
GT4, pp. 481-490.
McKenna, F. and Fenves, G. (2001). “The OpenSees Command
Language Manual: version 1.6.2,” Pacific Earthquake Engineering Center,
Univ. of Calif., Berkeley. (http://opensees.berkeley.edu).
Fragility Analysis of Reinforced Concrete Frame Structures507

December 2007, Dhaka, Bangladesh

NEHRP, 1991. National Earthquake Hazards Reduction Program.
Recommended Provisions for the Development of Seismic Regulations for
New Buildings. Building Seismic Safety Council, Washington, D.C., 1991.
Noor, M.A., Manzur, T., 2005a. Development of Fragility Curves for
R.C.C. Frame Structures: Bangladesh Context. First Bangladesh Earthquake
Symposium (BES-1).Dhaka, Dec. 14-15, 2005.
Noor, M.A., Yasin, M., Ansary, M.A., 2005b. Seismic Hazard
Analysis of Bangladesh. First Bangladesh Earthquake Symposium (BES1).Dhaka, Dec. 14-15, 2005.
Sharfuddin, M., 2001. Earthquake Hazard Analysis for Bangladesh.
M.Sc. Engg. Thesis, BUET, Dhaka.

508

New Technologies for Urban Safety of Mega Cities in Asia

FLOOD IN BANGLADESH WITH
FOCUSES ON 2007 FLOOD
MD. AYNUL KABIR
Flood Forecasting and Warning Centre, BWDB
aynulce@yahoo.com
MD. SAZEDUL KARIM CHOWDHURY
Processing and Flood Forecasting Circle, BWDB
sazed123@gmail.com
ABSTRACTAs a part of climate change over the world, the spatial and temporal
distribution of rainfall is changing day by day. And for this, the intensity offloods is increasing nowadays in many countries including Bangladesh withunusual timing. Unlike the past, the 2007 flood in Bangladesh occurred
relatively earlier. In this paper, the 2007 flood is extensively analyzed. It
reveals that the flood gave less time to the people for taking adequate
measures due to its earlier occurrence. At the same time, the flood that had
introduced earlier, ended quickly, most perhaps, because of the absence ofsynchronization of flood peaks at the GBM Rivers. The level of destruction
or extent of durations of past flood events (1988, 1998 and 2004) are also
found very much co-related with the synchronization of flood peaks at the
GBM Rivers. However, the temporal variability has stimulated this year’s
short duration flood in comparison to the floods in the past. Beside this, anumber of people living in flood plains also trigger high flood frequency aswell as huge loss. It is marked that breaching of flood protection
embankment at Serajganj and Gaibandha has worsened the overall flood
situation during the same period.

1. INTRODUCTION
Bangladesh is a part of the world’s most dynamic hydrological system. In
fact, the country is a fluid landscape framed by three major rivers: theGanges, the Brahmaputra and the Meghna (GBM). The country is highly
prone to natural disasters, especially hydro-meteorological disasters, for its
geographic location and topographic composition. Flood is considered here
as a regular event, which causes enormous loss of lives and properties
almost every year. On an average, 20% area of Bangladesh is affected byflood every year (FFWC 2005). The situation for monsoon river floods ismore complex and not fully understood (Khalequzzaman, 1994; Reavill andRahman, 1995; and Hofer and Messerli, 1997). Many studies, researches,
and investigations regarding this issue (e.g. Rasid and Paul, 1987; Khalil,
1990; Haque and Zaman, 1993; Paul, 1997; and Hofer and Messerli, 1997)
were conducted over the last few decades. It implies that complete flood
control in a country like Bangladesh is neither possible nor feasible. It is no
more flood control rather than the flood management. Now it has become509

December 2007, Dhaka, Bangladesh

inevitable to develop a plan to live or cope with flood and to take mitigation
measures to reduce the damages due to flood.
A Flood Information Cell (FIC) is running at Flood Forecasting andWarning Centre (FFWC) under Bangladesh Water Development board(BWDB) in action to the permanent orders of the Government of thePeople’s Republic of Bangladesh regarding disaster. FFWC presents amodel that gives forecast for maximum 72-hour interval. Forecast made by
FFWC using model revealed a very satisfactory approximation only in
different observation stations. FFWC activities are still limited to macrolevel applications. Additional efforts are required to reduce the impact offlood hazards in micro level. Flood risk assessment through comprehensive
study on past flood events could be an efficient and important tool providing
advance planning in flood disaster management for decision makers.
Main objectives of this study include of: (1) Analysis of past flood
events (1988, 1998 & 2004) and a comparison with 2007 flood. (2) Pictorial
analysis of different flood events (1988, 1998 & 2007) with respect tosynchronization of flood peaks at the GBM Rivers. (3) A brief review ofnonstructural measurements during 2007 flood. (4) Identification of current
flood plain and riverbed status by field observation. (5) A case study on
Serajganj with breaching and no breaching of flood protection embankment.

2. RECENT MAJOR FLOODS AND A COMPARISON WITH THE
YEAR 2007
Although floods occur every year in Bangladesh, the intensity andmagnitude of floods vary from year to year. The extensive flooding in
Bangladesh each year is related mainly to the three major rivers in the world– the Ganges, the Brahmaputra (Jamuna) and the Meghna. This section will
highlight on the flood events of recent years 1988, 1998, 2004 as well as
2007.
In 1988, the flood peak of the Brahmaputra and Ganges were very
high, but most significantly the peaks coincided, with devastating effects on
the Padma downstream of the Brahmaputra/Ganges confluence. The hugearea along the Brahmaputra, Ganges and Padma were flooded to an
unprecedented extent, and Dhaka was seriously affected at that period. 1988
flood established urban flooding as a national issue. The prolong flood in
the city caused severe loss of properties and to the business revenue, sointerruption to Govt. activities and commercial enterprise. There was an
exceptionally high flood on the Meghna basin due to the flood congestion in
the Lower Meghna.
The peaks in the Brahmaputra and Ganges again coincided in 1998,
causing severe flood and inundating more than half of the country. The
Brahmaputra reached its annual peak in July/August from heavy monsoon
rainfall. The Ganges started rising in June/July and attained the annual flood
peak in late August or early September. The Meghna at Bhairab Bazar

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reached the peak during August/September. This resulted in severe floodingin August/September in the three major river basins and periphery of the
Dhaka was also seriously affected in 1998. The 1988 and 1998 floods are
considered the most severe in recent experience. The main monsoon Aman
rice crop in 1998 was severely affected.
Generally the flash floods in the northeast region occur in April/May
and in the year 2004, this rapidly rising flood spilled over bank andeventually flew into the main lowland floodplains. Due to high intensity ofrainfall in the Meghalaya, the Barak and the Tripura river catchments andgreat rush of water from the northern hilly region due to vast deforestation,
rapidly rising river floods occurred in June-July causing over bank spills,
which was aggravated by the backing up of water in the Meghna River
resulting in deep flooding throughout the Sylhet depression and SurmaKushiyara floodplains. The rainfall and high flood level persisted
throughout July and reached at recorded highest level due to the backwater
effect from the Meghna, which also carried the Brahmaputra flood. This
resulted in severe flooding in the Brahmaputra and Meghna basin. Somestations in the major rivers experienced highest ever water levels in July.
In 2007, Meghna basin experienced moderate magnitude of flash
flood during third week of June and Northeast and Southeastern part of thecountry received approximately 20% above of monthly (June) normal
rainfall. July started with relatively dry spell, rainfall intensity rapidly
increased from 19th July as monsoon was vigorously active over Assam,
Meghalay, Auranachal Pradesh (Brahmaputra basin), Nagaland, Mizoram &Tripura (Meghna basin) and Bihar, East Uttar Pradesh, West Bengal &Nepal (Ganges basin) simultaneously. Floods started in Nepal, Assam,
Bihar and Uttar Pradesh from third week of July. In Bangladesh, flash flood
hit north-eastern part of the country from 20th July and onrush offloodwater from Assam, Bihar & Nepal has started coming through theBrahmaputra and the Ganges simultaneously from 22nd July. The rate ofrise of both the major rivers was very high and northern districts started
flooding from 28th July and after then the floodwater spread to central &south-central part of the country. Fortunately, the Ganges was flowing well
below from the danger level. In fact, July is not the proper time of Ganges
basin flooding. From the 1st week of August, dry spell prevails over the
GMB basins and water level started decreasing in the Brahmaputra from 1st
August and in the Ganges from 7th August. All the five small rivers in andaround Dhaka and Narayanganj crossed danger levels and caused flooding
especially in the eastern part and south-western part (outside of BWDB
flood embankment) of the Dhaka city. In this spell of flooding, the main
Dhaka city was well protected by BWDB flood protection embankment.
The flood damage of 2007 has yet to be calculated. According to thethorough investigation by Flood Forecasting and Warning Centre (FFWC),
42% (approximately) area of the country was flooded and 40 districts wereaffected in different magnitude.
The flood damages in 1988 and 1998 were estimated at US$ 1.2
billion & 2.8 billion respectively. The damage of 2004 flood has been

Flood in Bangladesh with Focuses on 2007 Flood511

December 2007, Dhaka, Bangladesh

estimated as US$ 6.6 Billion by UNWFP. The following table (Table 1)
provides a comparison of flood duration and flood affected areas of the
major floods since 1987 and the figure (Figure 1) illustrate water levels at
different stations of the major rivers.

0
23
34

0
54
59

68
49

39
72

37
19
62,000
(42)

27
68
72

56,000
(38)

2007
21
31

1,00,250( 68)

Number of districts affected

2004
16
19

89,970(61)

Flooded Area in Sq. Km.
(% of the country area)

1998
66
48

57,300(39)

Table 1: Comparison of Flood
Flood Year
Parameters
1987 1988
a. Bahadurabad (Jamuna)
13
27
b. Serajganj (Jamuna)31
44
c. Hardinge Bridge
Flood(Ganges)55
23
Duration d. Goalundo (Padma)
54
41(days)
e. Bhagyakul (Padma)
56
47
f. Bhairab Bazar(Meghna)30
68
g. Chandpur (Meghna)
16
27

50

53

53

39

40

(a) Water Level in Jamuna River at Bahadurabad

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ICUS Report 27(b) Water Level in Ganges River at Hardinge Bridge(c) Water Level in Meghna River at Bhairab Bazar
Figure 1: Comparison of Water Levels at the GBM Rivers

3. HISTORICAL FLOODS AND THE SYNCHRONIZATION OF
FLOOD PEAKS
Flooded area in Bangladesh calculated from the year 1954 to 2007 shown in
the figure (Figure 2). It reveals that approximately 37% areas are inundated
by floods of 10 years return period. Devastating floods of 1987, 1988, 1998
and 2004 inundated around 40-60% of the country. In fact, the prime causeof flooding was the synchronization of flood peaks of the three major rivers(GBM). Synchronization of flood peaks (especially, the Brahmaputra andthe Ganges) triggered large area flooding with relatively longer period in theyear 1988 and 1998. Figures (Figure 3a,b) show the synchronization offlood peaks in the year 1988 and 1998 for Bhahadurabad, Hardinge Bridge

Flood in Bangladesh with Focuses on 2007 Flood513

December 2007, Dhaka, Bangladesh

and Bhairab Bazar hydrological stations that represents the flow of theBrahmaputra, the Ganges and the Meghna rivers respectively. In 2007, theabsence of synchronization in the GBM rivers is pictorial (Figure 3c). As aresult, 2007 flood did not last long. But the continued rising of theBrahmaputra river from the middle of July, little bit earlier than that of usual,
gave less time to the people to be warned and damaged huge crops.
120000Flooded Area (km2)

100000

80000

60000

40000

20000

1954
1955
1956
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1980
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007

0

Year

Figure 2: Flooded Area from the year 1954 to 2007

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Figure 3: Synchronization of Flood peaks at the GBM Rivers (1988, 1998 &2007)
4. NONSTRUCTURAL MEASUREMENTS DURING 2007 FLOOD
In 1972, Flood Forecasting and Warning Centre (FFWC) formed under the
Bangladesh Water Development Board (BWDB). FFWC has been playing
key role in flood forecasting since the beginning. The activities of FFWC
are very important considering the geography of Bangladesh. And at sametime, flood forecasting in Bangladesh is very difficult due to having its
complex hydrology. For a long term, FFWC has forecasted the numericalvalue of water level in different rivers of the country using mathematicalmodel. But in 2007, FFWC tried to explain all the forecasted results in acompressive way. Besides, in some cases, five to seven days qualitative
forecast has also been disseminated by FFWC in the same year. Figure(Figure 4) shows a comparison of 24/48/72 hrs forecast with observed data
at Bahadurabad, Goalundo and Bhairab Bazar hydrological stations during
July 20 to August 15, 2007.

Flood in Bangladesh with Focuses on 2007 Flood515

December 2007, Dhaka, Bangladesh

Water Level (PWD meter)

21

20

19

Observed Data
24 hr Forecast
48 hr Forecast
72 hr Forecast

18

17
20Jul

22Jul

24Jul

26Jul

28Jul

30Jul

13Aug Aug

5Aug

79Aug Aug

11- 13Aug Aug

15Aug

T ime (year 2007)(a) Jamuna River at Bahadurabad

Water Level (PWD meter)

11

10

9

Observed Dat a
24 hr Forecast
48 hr Forecast
72 hr Forecast

8

7
20Jul

22Jul

24Jul

26Jul

28Jul

30Jul

1Aug

3Aug

5Aug

7Aug

9Aug

11Aug

13Aug

15Aug

T ime (year 2007)(b) Ganges River at Hardinge Bridge

Water Level (PWD meter)

8

7

6

Observed Data
24 hr Forecast
48 hr Forecast
72 hr Forecast

5

4
20Jul

22Jul

24Jul

26Jul

28Jul

30Jul

1Aug

3Aug

5Aug

7Aug

9Aug

11Aug

13Aug

15Aug

(b) Meghna River at Bairab Bazar
Figure 4: 24/48/72 hr Forecast Results versus Observed Data (year 2007)

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5. RECENT FLOOD PLAIN IN BANGLADESH AND A CASESTUDY ON SERAJGANJ
A number of people living in flood plains is increasing day by day and it
triggers high flood frequency as well as huge loss. On the other hand, water
carrying capacity of the rivers is decreasing chronologically due to siltation.
It is no more obscure that riverbed aggradation on a contrary to substantial
compaction of sediments in our delta prevails a critical morphology inwhich some settlement areas have already gone below the usual water levelin the river. Similar phenomena have been observed on 29th July 2007 near
the Gangachara thana in adjacent to the river Teesta which is pictorial as
shown in the figure (Figure 5).

Figure 5: Teesta River State at the Gangachara Thana
For this, the breaching in the flood protection embankment/levees
could be a cause of flooding in huge areas. In 2007, breaching in flood
protect embankment at Serajganj and Gaibandha has worsened the overall
flood situation. Figure 6 shows the inundation areas of Sirajganj district asof August 01, 2007. The inundation maps have been derived using MIKE 11hydrodynamic model and MIKE 11-GIS. It is worth mentioning here thatthe Digital Elevation Model (DEM) used to produce inundation maps iscoarse (900-meter resolution) and is not sufficient to produce good maps.
Rather it is old enough to represent the actual scenario. However, water
surface calculated in the embanked area of Serajganj district is around
34.3% of the total area in case of no breaching of embankment as shown in
the figure (Figure 6a). But at the same time, the water surface area wasfound 79.6% of the total area for the case of 20 Km breaching ofembankment as shown in the figure (Figure 6b). Similar investigation isundergoing for Dhaka city.

Flood in Bangladesh with Focuses on 2007 Flood517

December 2007, Dhaka, Bangladesh(a) Inundation map considering no breaching(b) Inundation map considering 20 Km breaching
Figure 6: Inundation maps of Serajganj district as on Aug 01, 2007

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6. CONCLUSIONSThe spatial and temporal distributions of rainfall are changing day by day.
Beside this, a number of people living in flood plain are creasing due to nothaving enough space. For this, flood intensity has increased now a day.
Synchronization of the GBM Rivers is still identified the prime cause ofmajor flooding in Bangladesh. Water carrying capacity of the rivers has
decreased sufficiently due to siltation. The reduced level of high river-bed
elevation with respect to the settlement area has become a great concern for
Bangladesh. Breaching of flood protection embankment could be a causedof flooding in huge area. Flood risk assessment and long term flood
prediction need to be adopted as a part of non-structural measurement.
In the conclusion, the 2007 Flood although initially seemed to be alethal one has receded quickly due to lack of synchronization of theBrahmaputra and the Ganges rivers.

REFERENCES
FFWC, 2005. Annul Flood Report 2005. Flood Forecasting &Warning Centre (FFWC), Bangladesh Water Development Board (BWDB).
Haque, C.E., and M.Q., Zaman, 1993. Human response to riverine
hazards in Bangladesh – A proposal for sustainable floodplain development.
World Development 21, No. 1: 93-107.
Hofer, T., and B., Messerli, 1997. Floods in Bangladesh, Process
understanding and development strategies. A synthesis paper prepared for
the Swiss agency for development and cooperation. Institute of Geography,
University of Berne. 32 pp.
Khalequzzaman, Md., 1994. Recent floods in Bangladesh: Possible
causes and solutions. Natural Hazards 9: 65-80.
Khalil, G.M., 1990. Floods in Bangladesh: A question of disciplining
the rivers. Natural Hazards 3: 379-401.
Paul, B.K., 1997. Flood research in Bangladesh in retrospect andprospect: a review. Geoforum 28, No. 2: 121-131.
Rasid, H., and B.K., Paul., 1987. Flood problems in Bangladesh: Is
there any indigenous solution? Environmental Management 11, No. 2: 155173.
Reavill, L.R.P., and T.G., Rahman., 1995. A systems-science-based
analysis of the factors that influence and aggravate the effects of flooding in
Bangladesh. Technological Forecasting and Social Change 49: 89-101.

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New Technologies for Urban Safety of Mega Cities in Asia

A STUDY FOR IMPROVING TOTALDISASTER REDUCTION ABILITYOF NURSERY SCHOOLSAND KINDERGARTENSMARIKO ABE1 and KIMIRO MEGURO2
International Center for Urban Safety Engineering
Institute of Industrial Science, The University of Tokyo, Japan
abe@risk-mg.iis.u-tokyo.ac.jp
meguro@iis.u-tokyo.ac.jp
ABSTRACTIn the field of protecting small children in the event of disasters, wehave various problems such as many seismic-vulnerable facilities or
miscommunication among concerned parties. Improving the disasterimagination ability is necessary for these people to solve these problems.
Therefore, the authors made the disaster situation image-training tool
named Meguro-maki from the Meguro-method (Meguro, 1999). Then theauthors designed the workshop using Meguro-maki and conducted it atnursery schools among others.
Furthermore, the authors made Meguro-maki stories based on pastearthquake disaster cases and expert opinions to support Meguro-maki
making and developing disaster mitigation ability. The authors also made apamphlet for pregnant women and little children’s parents using thesestories.

1. INTRODUCTION
When small children (in this paper, “small children” means infants and kids
under six years old, that is before elementary school age) face unpredictable
dangers such as an earthquake, fire or an intruding malicious person, theyneed adult’s help. Today, in Japan, typical places in which small children
gather are nursery schools and kindergartens. The former take care of
infants who are only several months old. In these groups, because thenumber of children per adult is larger than that of a regular home, the loadon adults when disaster occurs is heavier.
In this study, we propose a system to raise the disaster management
ability of these groups by establishing an independent and permanent
disaster management cycle starting from "Imagining the disaster situation"
up to "Perception of the present state of affairs and problem grasping" and"Design and implementation of countermeasures." In order to "imagine thedisaster situation" and "perceive the present state of affairs and grasp the
problems", we suggest carrying out disaster management workshops called521

December 2007, Dhaka, Bangladesh“Meguro-maki WS”, in which “Meguro-maki”, a tool to imagine thedisaster situation, is used.
An additional positive effect of our proposal is the increase of thedisaster management awareness of the whole community. When children’s
parents, relatives, and people interacting with them learn about nurseryschool disaster management activities, they themselves become aware that
“disaster management is important” and embrace it even if they did notconsider it as their own problem before. Furthermore, focusing on nurseryschools and kindergartens creates a disaster mitigation culture among smallchildren that will become a valuable asset for the society in the future.

2. METHODOLOGY
2.1

Importance of disaster-imagination

To deal with the various problems of disaster mitigation appropriately
under the severe conditions of the limited members, time, and items, etc, itis necessary to imagine disaster situations. If you don’t have enoughimagination about your possible disaster situations, your efforts for disastermitigation tend to be useless or wrong. When you try to imagine the disastersituation appropriately, it is important to consider various factors on
regional characteristics composed of social and natural environmental
conditions of the region. Also, as human acts and social activities arestrongly dependant on time, time related factor, such as season, weather, dayof the week, time of the day etc. on which the earthquake occurs, isimportant. And of course, your individual conditions such as your family
members and living house are important. Moreover, the situation changes
according to the passage of time from the hazard occurrence. What and how
much you need changes in relation to the elapsed time.
2.2

The Meguro-method

The Meguro-method has been developed in response to thesecontextual factors. The concept of Meguro-method is "After setting various
conditions, imagine your situation and action and feelings, etc. according to
the passage of time after the hazard occurrence.” In general, the table like
Figure 1 is used in the Meguro-method. This table is divided in detail with avertical and horizontal axis. The vertical axis shows "your typical action
pattern along the passage of time during a day". When you fill in theseblanks, you should consider the earthquake resistance conditions of theenvironment around the region where you live and work, conditions oflocation, and the indoor furniture arrangement, family structures, and eachmember's action patterns, etc. A horizontal axis is "time passage since theearthquake occurs", like three seconds later, ten seconds later, one minutelater, two minutes later, several minutes later, one hour later, one day later,…one week later, …one month later, …one year later, …ten years later.
You may flexibly change a unit of the division length and a final time522

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

passage as this time division responds to your purpose and the writing time
limit.
When some people write the Meguro method, the facilitator uses somemasses in the table as examples and explains the purpose and “how to image
their disaster situations”. For instance, he/she shows the mass "A1a” andmakes them imagine "What will your situation be after three seconds whenthe earthquake happens while sleeping?" Usually a digital worksheet is used
to collect and analyze the data easily. Through practices of filling in the
Meguro-method, the writer’s disaster imagination ability such as "Whathappens in my environment as time has passed since the earthquake
occurred?" can be improved. After that, the facilitator asks the writers ifthey could imagine the disaster situation appropriately. For example, thefacilitator comments about the possibility of a "situation in which the writeror his/her family members get injured or die." He/she asks “Why are only
you are OK in spite many people are killed or injured?” The facilitator uses
various pictures and videos of past earthquakes in order to reinforce thewriter’s disaster imagination. Because the writers imagine their own
situations, they can feel reality. If the writers fill again the tables withdifferent conditions, they will recognize what will change and what will not.
Some will drastically change and some will not. Next, the writers think“what can we do to reduce the negative impact?” Based on this,countermeasures can be implemented.
years
５ years
３ years
２ years
１ year６ months
３ months
２ months
１ month
２ weeks
１ week３ days２ days
１ day
hours
６ hours
３ hours
２ hours
１
hour
min
min
５ min
２ min
１ min
sec
sec
sec

Earthquake→→ → →→ → → → → → → → → → → → → →→ → → → → →→ → →Day-life
patternab c d eA 1 A 1a

3：00

f g

h i

j

k l

m n o

p

q r

A 1h

sleep

A2
・
6：00 Get up ・
Go to office A n

9：00
12：00

job

B1

lunch

B2

B3
・
・
18：00 Go home P 1
・
・
21：00
・
Pn

15：00

job

B 1e

B 3b

B 3k

P 1e

P 1o

s

t u v w x yz aa

When influence of the event occurrence time was lost

0：00

10

12

10 30

3 10 30

24：00

Figure 1: Disaster situation story table
2.3

Meguro-maki & Meguro-maki Workshop

The "Meguro method" is a very effective tool to imagine the disastersituation in detail. However, it is a hard task for beginners and busy people
to use the Meguro-method. Therefore, it is necessary to simplify the Meguro
method for busy childcare people.

A Study for Improving Total Disaster Reduction Ability of Nursery Schools and Kindergartens523

December 2007, Dhaka, Bangladesh

Because nursery teachers do not have a sufficient number of PCs, thetool must be written by hand. Also, because they are very busy, the tool
must be written in about 30 minutes. To meet these requirements, theauthors prepared “Meguro-maki” from the Meguro-method. “Maki” means“long roll”. The writing board of Meguro-maki is a long paper intended tobe lined up on the table and read through the times. The authors made theworkshop (WS) using Meguro-maki.
While in Meguro-method several possibilities are considered, Onlysome conditions and the time axis are on the board. The conditions are theseason, the day of the week, time, weather, the writer’s positions at theoffice or his/her family, and the seismic intensity (in case of the earthquake).
First, the writers decide the conditions. While deciding the conditions, there
are two important aspects. One is frequency and the other is unpleasantness.
After the writers decide the conditions and situations when the disasteroccurs, they start writing disaster situations as time passes. The facilitatoradvises the writer “Please write your own story after the disaster occurs.
You are the central figure of the story. What will your situation be and what
will you think and do? How about other characters like your family, yourneighbors, your coworkers etc.?” Usually, when Meguro-maki WS is held atnursery schools or others, at the first WS the leader and some members do
the imagination exercise. At the second WS, the first WS members become
the facilitators. The facilitator helps other to imagine the disaster situation if
they cannot write smoothly. If the writer becomes aware of the questions
and problems, he/she writes down these things on the memo pads. After all
the members finish writing, they line up Meguro-maki on the table and readeach story. It is interesting for each member to read the other members’
stories.
They compare Meguro-maki stories as time passes. Sometimes theimages of each member are different. They can consider the situation andhow to manage it through such communication. Through this practice, WS
members can share their disaster images and problems. It is important tofind and recognize the problems and solve the problems as a group.
Im agine your situation after disaster,and m ake a story of yourself

W rite in yoursituation w hen thedisaster occurs

Fix the typeof disaster
Earthquake

MeguroMaki

DATE

震度６強 Earthquake10Occur
sec.

SEISMICINTENSITY 6-odd

1 min.

.Sun.

your situation Gather andsurroundwinterfairbabiesWe’re playing
Call nurwith babies.
by mob（ Teachers: 2 BABIES
phone
ABE. Mariko 0-1 years old
NurseryADULTS
parent babies: 6）
worker

CONDITIONS
-R
AE
EH
WT

N
O
S
A
E
S

E
M
I
T

大人

R
E
T
I
R
W

n
o
i
t
i
d
n
o
c
e
h
t
t
e
S

teacher

Figure 2: Meguro-maki writing board

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New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

Figure 3: How to use Meguro-maki

A Study for Improving Total Disaster Reduction Ability of Nursery Schools and Kindergartens525

December 2007, Dhaka, Bangladesh

3. MEGURO-MAKI WS AT VARIOUS GROUPS

We have held Meguro-maki WSs at nursery schools, kindergartens andother various groups (Fig 4). Through these practices, we found someproblems. It is difficult for beginners to imagine the disaster situation
without help from the facilitator. And to motivate nursery schools andkindergartens, a combined approach of the government and parents’ side isimportant.

nurseryteachers

parents

home

officekindergarten
hospital
day-care centercitizen hall

Figure 4: Meguro-maki WS in various situations

4. MAKING DISASTER SITUATION STORIES FOR REFERENCE
AND PAMPHLET

To solve these problems, the authors cooperated with Tokyo Metropolitan
Government and made Meguro-maki reference stories based on pastearthquake disaster cases and expert opinions as the support for making
Meguro-maki and having disaster mitigation ability. Then the authors andthe Tokyo Metropolitan Government made a pamphlet for pregnant womenand little children’s parents using these stories.
We conducted a questionnaire survey with the people, mainly little
children’s guardians, who experienced the Niigata Prefecture Chuetsu
Earthquake (M6.8, October 23, 2004). We asked about the situation whenthe earthquake occurred, their characteristics such as family members andliving house, etc. In addition, we asked about their disaster situations,actions and feelings thorough the time passage. Then, we transfer theirmessages to other pregnant women and little children’s guardians who neverexperienced big earthquakes. After that, we analyzed these data and makedisaster situation stories. One main character is a pregnant woman and otheris the mother of a baby. Then, we made a pamphlet for pregnant women andlittle children’s guardians in Tokyo.

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W hat w e can do for our children before earthquake occurs –For pregnant w om en & little children’s guardians
C ontents
１．Introduction
２．D isaster m itigation before
earthquake occurs（house,room s,
item s,inform ation & com m unication）
３．D isaster situation story forreference (2 stories)
４．Your ow n story (blank story pad)
５．M essage by the disaster
東京都
experienced people
６．D isaster prevention inform ationof Tokyo M etropolitan G overnm ent Tokyo M etropolitan
７．R eference of books & w ebsites
G overnm ent
Figure 5: Disaster situation story
5. CONCLUSIONSIn the field of saving small children in the event of disasters, we havevarious problems such as many seismic-vulnerable buildings, or
miscommunication among concerned parties. To improve the disasterimagination ability, it is necessary for those people to solve these problems.
Therefore, the authors made the disaster situation image-training tool
Meguro-maki from Meguro-method (Meguro, 1999). Then, the authors
designed workshops using Meguro-maki and conducted it at nursery schools
among others.
Furthermore, the authors made Meguro-maki stories based on pastdisaster cases and special findings as the support for making Meguro-maki
and developing prevention power. Then, the authors made a pamphlet for
pregnant women and little children’s parents using these stories.
Using, verifying the case collection, creating a further database, andmaking other support systems are scheduled to be done in the future.

REFERENCES

Meguro, K., 1999. Lifeline earthquake disaster and its
countermeasures, Comprehensive course on disaster reduction, Urban
Disaster Mitigation Part, Shizuoka Prefecture, pp.33-55 (in Japanese)

A Study for Improving Total Disaster Reduction Ability of Nursery Schools and Kindergartens527

December 2007, Dhaka, Bangladesh

528

New Technologies for Urban Safety of Mega Cities in Asia

SCHOOL EARTHQUAKE SAFETYPROGRAM (SESP) IN OLD DHAKA,BANGLADESHISRAT JAHAN
Research Assistant, BNUS, BUET, Bangladesh
sheulyurp@yahoo.com
MEHEDI AHMED ANSARY
Professor, Dept. of Civil Engineering, BUET, Bangladesh
ansary@ce.buet.ac.bd
ABSTRACT
Dhaka as one of the densely populated cities of the world requires
hazard risk assessment and needs preparedness to reduce risk. The
earthquake risk is more prominent for Dhaka due to its high population
density, vulnerable structures, low preparedness, etc. The inhabitants of thecity must learn how to reduce risk due to any disaster. To reduce loss the
inhabitants of the city must learn what to do to cope with the disaster andminimize the risk at that time. In this perspective the school awarenessprogram is important as the young generation of the country will probably
response more eagerly than others and will play a vital role in spreadingout the ideas and knowledge among their friends, family and surroundings.
Schools are considered as shelter place during any natural hazards in
Bangladesh. Schools should be made earthquake resistant and its
inhabitants need to know how to cope with any disaster. The structures of
Old Dhaka is relatively more vulnerable against earthquakes. To reduce
loss in times of any disaster, a school based earthquake safety awarenessprogram has been organized in Govt. High schools in the older part of
Dhaka to train the students and spread out the ideas. Earthquake risk
reduction and preparedness program in this school covered: (a) seminar toaware about earthquake disaster, (b) short course on First Aid, (c) searchand rescue training, and (d) safety drill in Schools.

1. INTRODUCTION
Dhaka, the capital of Bangladesh is the center of economy, commerce,
politics and society, with a large population of more or less 12 million.
According to a report published by United Nations IDNDR-RADIUS
Initiatives, Dhaka and Tehran are the cities with the highest relative
earthquake disaster risk (Rahman, 2004). Earthquakes may cause billions of
Taka worth of damage (Ansary, 2004). Once a great earthquake occurs,
Dhaka will suffer immense losses of life and property. This will have very
severe long term consequences for the entire country. This is of particular
relevance to Old Dhaka which has large numbers of densely packed very
old non-reinforced masonry structures along narrow winding streets. There529

December 2007, Dhaka, Bangladesh

is no earthquake disaster management system in Dhaka and with the active
involvement of the local community this system will be effective. There is asaying among the earthquake experts: "earthquakes do not kill, what kills is
a building that falls, a gas escape or a column". "The human factor changes
a natural hazard into a disaster" (Campo, nd). That is why it is very
important to reduce human vulnerability through prevention, learning of
preventive measures and drills.
The School earthquake awareness program is important as thestudents are the future generation of the country and their response andcontribution in this sector is more far fetching than any other group as ayounger generation. They also play a vital role in spreading out the ideas
and knowledge on earthquake preparedness among their friends’ circle,
family level and surrounding locality. Again most often the schools are
considered as the Shelter place from any kind of disaster in this country. So
it is an emergency task to make the school building safe during and after theoccurrence of disaster ensuring the safety of its residing people, i.e. thestudents. It is of primary importance that the students of the schools should
train up to help themselves and provide support to others. To reduce loss the
inhabitants must learn what to do to cope with the disaster. If they motivate
people, they can play an effective role in risk mitigation, and reduce theimpacts of any urban hazard especially earthquakes.

2. PURPOSE OF THE AWARENESS WORKSHOP IN SCHOOL
•
•
•
•
•

To initiate discussions with the school people and the community
Acknowledge the important role of school buildings within thecommunity as post-disaster shelters.
To promote earthquake awareness through students and staffs ofschools
To Establish School Earthquake Safety Committee
To conduct preparedness and mitigation programs like first aid
training, search and rescue training and earthquake drills to reduce
the loss of lives and properties due to earthquake

3. RATIONALE OF THE STUDYIn Bangladesh, recently due to poor construction quality of buildings, threebuildings collapsed. In June 2004 a five storied building collapsed in
Sakhari bazar, Old Dhaka that killed 19 people and and injuring several
others among it’s 30 inhabitants. In April 2005 a nine-storied factorybuilding collapsed in Savar that killed 70 people and injuring around 200
others among its 300 workers. In February 2006 a five storied underconstruction building collapsed in Tejgaon that killed 18 and injured 40
workers. During an earthquake this will multiply thousand times more. Also
due to poor fire preparedness in high-rise buildings of Dhaka city, manybuildings may catch fire and people may die due to lack of poor evacuation

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facilities. If the people are aware how to cope with the disasters, the losses
will be less than what happened in the above cases. Also the trained persons
could help in searching the victims and rescue them from the debris. If thelocal people are trained up they can response earlier than the outside help
such as Fire Service Department, Armed Forces, etc. In emergency case thislocal trained volunteer group will come handy in reducing the effects of thedisaster. So the students should be trained up so that they can carry out
rescue work and provide first aid to the injured of their communities and intheir schools.

4. SCHOOL EARTHQUAKE SAFETY PROGRAM
Meetings, structured discussions, power point presentations, interviews andan evaluation questionnaire designed to get feedback from the participants
are among the tools used during the school awareness workshops. To fulfill
the objective, the school awareness-training program covers:• Brief discussion on earthquake that spreads out the ideas onearthquake, techniques to cope with such an uncertain situation, how
to tackle the unwanted situations, how to minimize the losses due tothe earthquake disaster, etc.
• First aid training• Search and Rescue training• Mock drills
4.1

Surveyed schools under the program

BNUS (Bangladesh Network Office for Urban Safety) has conducted
some earthquake safety related programs in several schools in old part of
Dhaka city. These schools are situated in the most densely and hazardous
area of Old Dhaka, which is the most vulnerable site due to earthquake inthis city for its high density and unplanned build-ups. In order to increase
the knowledge base and making the students fully aware of their statusduring and after a disaster, BNUS has undertaken this program. The safety
program has been launched in Armenitola Govt. High School (located at
Ward 68) in September 2006.
4.2

Open discussion on earthquake vulnerabilities

The earthquake school awareness program in Armenitola Govt. HighSchool has been started with an open discussion on earthquake with theteachers, students and young volunteers of Bangladesh Red CrescentSociety and Bangladesh Scout in 21 September 2006. Figures 1 and 2 show
glimpses of the seminar. The discussion covered earthquake vulnerabilities,
earthquake preparedness and disaster mitigation measures that focuses theoutcomes from the participants on how to manage the situation before,
during and after earthquake occurs, what are the duties of each individual,
what to do to minimize the loss and cope with the casualties due toearthquake, how to provide help to the helpless, what disciplines should be

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followed to come out in a safe open place without any injuries, etc. From
the discussion it was realized and agreed by the participants that first aid
training, search and rescue training and regular mock drill on safety issues isneeded to save lives and to minimize the loss due to disasters. Mock drills
must be carried out regularly to have a disciplinary technique to be followed
during and after disaster occurrence to safeguard against loss.

Figure 1: Prof. Ansary giving his speech on Earthquake awareness

Figure 2: The teachers and the students was present in the program
According to the suggestion that came out from the open discussion
BNUS organized training on Earthquake safety awareness that includes
short course training on First Aid, Search and Rescue training and final
demonstration. The full program concludes with making the students fully
aware of their duties in pre, during and post disaster periods.
4.3

Short course on First Aid

First Aid is an initial assistance or treatment given to someone who isinjured or suddenly taken ill. First Aid training makes any individuals toremain aware and safe by themselves and provide help to others injured
during and after any disasters. In order to make the students fully aware ofany disaster especially in case of earthquake, first aid training is of utmost
importance to safe lives.

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A short course on First Aid has been held in Armenitola Govt. HighSchool from November 30 to December 02, 2006 with 77 students of class
VI to IX selected by the school authority. The students are from generalgroups and the members of Red Crescent and Scout. The general knowledge
on primary treatment and special care during injuries especially withcasualty due to earthquake was given emphasis in this program. The
duration of the training is short to make a person totally capable to manage afirst aid required for a person. The training would rather extend help to otherfirst responders such Fire Brigade, Red Crescent members during a disasterto reduce pain and casualty.
4.3.1 Objective of Giving First Aid training to any person•••

Train them with the basic principles and practices of the First Aid
to provide help during and after any kind of disasters that could
save a life and reduce sufferings,
Make them aware of what they can do in providing first aid topeople in emergency care,
Help people avoid, prepare for and cope with emergencies.

4.3.2 Items covered under First Aid Training
The general knowledge on primary treatment and special care during
injuries especially with casualty due to earthquake was given emphasis in
this program. The students learned practically all the techniques of giving
first aid.
Introductory speech on First Aid Awareness: What is First Aid,
general knowledge of the students about First Aid, Objective of First Aid,
Principles of First Aid, Responsibilities of a First Aider, etc. Spread out theideas on:• Techniques of giving First Aid in case of Airway, Breathing andCirculating (ABC) Disorder• Major cause of respiratory problems, Artificial Respiration, waysof giving respiration and CPR• Heatstroke• Shock, Unconsciousness and Fainting• How to treat a burn casualty, Burns Scalds and Acid burns• Bleeding, Wounds, Dressings and Bandages, Pressure bandage
and how to dress a fresh wound• Immobilize the injured part, lower and upper arm sling, chest, legand skull bandage.
• Fractures, Strains and Sprains• Poisoning, Bites and Stings• First Aid materials• Carrying and transport of casualty• How to place a casualty in recovery position.

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Figures 3 to 8 show different stages of the training.

Figure 3: The ABC Technique ofFirst Aid

Figure 4: Managing the bleeding

Figure 5: Bandage in Chin injury

Figure 6: Bandage in Head injury

Figure 7: Settling down an injured
Arm

Figure 8: Make a patient breathe
easily and comfortably

4.4

Search and Rescue Training Program

The third step of the program covered Search and Rescue (SAR)
training on how to deal with casualty after a disaster. A three days programwith 5 hours per day has been organized by BNUS in Armenitola Govt.
High School December 11 to 13 2006. The students who got the first aid
training are selected for the next step of search and rescue training program

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that is the required doings in the after disaster part. There were 33 students
from the 77 first aid trainee students.
4.4.1 Topics covered under SAR training
Different Steps in SAR:
• Survey• Observation• Information• Plan• Actions
General knowledge on different Stage of Search and Rescue (SAR):
Lectures on:• What is Survey?
• How can they do the survey work?
• Types of Survey:
 Primary Survey
 Detailed Survey
 Specialized Survey• Ways of observing the damaged part of the area.
• Necessity and methods of collecting information on damaged
property?
• Plan to handle the situations perfectly. How to make anappropriate plan with the importance of making appropriate
and successful plans? What is the right plan in that momentwith details? Ways to develop the plan.
• Finally, why and how an action can take place?
Stage of Rescue:• 1st Stage: Emergency Rescue• 2nd Stage: Search in of slightly damaged building.
• 3rd Stage: Immediate rescue• 4th Stage: selected debris clearance
General Techniques of Rescue:• Different styles of rescue from a damage sector• Technique of Stretcher use with causalities• Causality leave with fireman using a chair knot
• Technique of Debris cleaning’s
Figures 9 to 14 show different stages of SAR training.

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December 2007, Dhaka, Bangladesh

Figure 9: Bow line dragging

Figure 10: Toe dragging

Figure 11: Technique of Fireman
Lift

Figure 12: Crawling

Figure 13: Stretcher blanketingwith rope

Figure 14: Casualty leave using
stretcher

4.5

Mock Drill

Finally a mock drill has been organized showing all the techniques ofsearch and rescue, ways of first aid, demonstration showing the duties
before, during and after an earthquake to have a clear cut view of theearthquake situation. It is the way of disseminating what they have learnt.
The earthquake mock drill was organized by BNUS with assistance of 12
Trainers from Bangladesh Red Crescent Society at Armenitola Govt. High536

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School, Dhaka on 23 February 2007. The drill lasted for 100 minutes. Total
150 students participated in the drill among them 33 was SAR trainees, rest
were first aider and other general students. The program was under theleadership of already SAR trained 33 students. The Guardians of thestudents and the Schoolteachers were also present in the program in order tospread out the knowledge on earthquake safety. In the program the students
presented their duties before, during and after an earthquake. Figures 15 to
19 show different scenes of the mock drill. To increase awareness eachschool student has given an earthquake awareness poster already made forthe Dhaka city (Figure 20).

Figure 15: A Scene of Earthquake Mock drill

Figure 16: Casualty leave using
Firemen Chair knot

Figure 17: Casualty leave using
Stretcher

Figure 18: First Aid Post

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Figure 19: Carrying a casualty

Figure 20: Earthquake Awareness Poster

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5. SUSTAINABILITY OF THE PROGRAM
The training program is very effective in facing a disaster in respect of
reducing the losses. The loss due to any hazard becomes greater if anappropriate measure is not taken in time. The trained up students arethemselves a great resource considering the future prospects. They will also
work in spreading out the knowledge base in awareness creation. The
students will actively take part in reducing the loss from any disaster. Livingin the affected or surrounding areas the local community may response mosteffectively before the outside help reaches in their area. And a trained up
community can reduce the loss much more than the untrained. The students
will spread out the ideas and knowledge on earthquake safety awarenessactivities and necessary duties to minimize the sufferings from disasters.
Emergency first aid service and other life saving measures candrastically reduce sufferings and save more lives. These students will workas the leader in their respective classes and guide in tackling any unwanted
situation. They will also lead in safety drill in their school. The students who
got the search and rescue training and the first aid training will be selected
for the next step of earthquake safety drill. Afterwards the safety drill will
be undertaken regularly in their school.
The trainee students will work as the following:• Save lives providing first aid and service to minimize the riskof death and future injury.
• Immediate transfer to minimize the shock and reduce
suffering• First Aid team at local community level.
• The students will actively take part in reducing the loss fromany disaster.
• The students will spread out the ideas and knowledge onearthquake safety awareness activities and necessary duties
to minimize the sufferings from disasters.
• Emergency first aid service and other life saving measures
can drastically reduce sufferings and save more lives.
The Search and Rescue training program is very effective after any
disaster occurs in respect of reducing the losses. The loss due to any hazard
becomes greater if an appropriate measure is not taken in time. The trained
up students are themselves a great resource considering the future prospects.
They will also work in spreading out the knowledge base in awarenesscreation. These 33 students will work as the leader in their respective classes
and guide in tackling any unwanted situation. They will also lead in safety
drill undertaken in their school. The headmaster of the school wishes tounder take safety drill program regularly in their school.

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6. CONLUSIONS
Earthquake risk reduction action plan cannot be successful unless the people
at risk in the hazardous zone aware themselves about the risk and considers
earthquake safety issues as part of their life and society’s culture. The
enthusiasm and potential of the school people was exciting and such schoolcommunity work should be a part of future efforts of any Safety related
Project. Schools play a vital role in every community. Schools teach civics,
educating citizens of their rights and duties. They foster an appreciation ofculture through the study of literature and the arts. Schools are a measure ofcommunity well being. Earthquake threatened communities needearthquake-resistant school to protect their teachers and children. In order toreduce Old Dhaka’s earthquake risk, the processes started by this projectneed to be continued for at least several years.
Recommendations for school based disaster management plan
• Emphasize preparedness for natural and technological disasters.
• Prepare charts, outlining who does what in disaster prevention,
mitigation, preparedness and response.
• Define the tasks to be fulfilled by the team and the support theyneed from the authorities.
• Include the BNCC, Red Crescent more fully in support ofresponse to warnings and disasters at all level.
• Reinforce cooperation between different organizations (Fireservice, Red Crescent Society) and school.

REFERENCES
Ansary, M.A., 2004. Seismic Loss Estimation of Dhaka for an Earthquakeof Intensity VII. Oriental Geographer, Dhaka University.
Campo, M. A., nd, 2006. Study of Awareness of Earthquake Risk in the
population of Mendoza. URL: http://proventionconsortium.org/files.
Rahman, M. G. F., 2004. Seismic Damage Scenerio for Dhaka City. M.Sc.
Engg. Thesis, Department of Civil Engg., BUET, Dhaka

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VULNERABILITY RISK AREAS OF
BANGLADESH DUE TO MULTIPLE
NATURAL HAZARDSMUSA. SHAMMI AKTHER
Graduate Student, Department of Civil Engineering, BUET, Bangladesh
shammii_bd@yahoo.com
MEHEDI AHMED ANSARY
Professor, Department of Civil Engineering, BUET, Bangladesh
ansary@ce.buet.ac.bd
ABSTRACTThis paper highlights the complete district wise database for natural
disasters in Bangladesh and identification of vulnerable areas withreference to different natural hazards. A basic requirement in this regard isto prepare a Vulnerability Atlas, showing specific areas vulnerable to one
or more natural disasters. Secondary data and information is collected fromthe census report as well as from various government and non-governmentorganizations such as Bangladesh Meteorological Department (BMD),SPARRSO, Disaster Management Bureau (DMB) and concerned nongovernment organizations (NGO). This study is undertaken to identify thehistorical disaster events, their duration and damage information. GIS is a
powerful planning tool, which is used to identify the disaster prone areas in
Bangladesh. The existing disaster data and zoning maps are criticallyreviewed. The location, type, year and damages etc are stored into a
database. Based on the available historical data gathered from different
sources, the disaster prone area of Bangladesh is identified.

1. INTRODUCTION
Bangladesh is one of the most natural disaster prone areas in the World. The
different types of disasters like flood, cyclonic storms, tidal surges, droughts,
tornadoes, riverbank erosion, earthquake, etc. occur in Bangladesh regularly
and frequently. The most devastating cyclones and floods of the world
occurred in Bangladesh. The 1988 flood killed 1517 people and nearly halfof the population was affected (Hossain, 2006). The 1970 cyclone killed
almost 500,000 people (Karim, 1996). About 1300 people were killed bytornado at Saturia of Manikganj district in Bangladesh in 1989 (EIA, 2004).
The 1897 Great Indian Earthquake with a magnitude of 8.7 and considered
to be one of the strongest earthquakes in the world killed 1542 and affected
almost the whole of Bangladesh (Oldham, 1899). Crop and livestock loss
was extremely high. Major factors responsible for disasters in Bangladesh
are flat topography, rapid run-off and drainage congestion, low relief of thefloods plains, low river gradients, heavy monsoon rainfall, enormous
discharge of sediments, funnel shapes and shallow Bay of Bengal etc.

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Bangladesh is a developing country with numerous problems like
overpopulation, poverty, complex socio economic structure, frequentdisasters, low level industrial base, resource constrains, lack of appropriate
infrastructural and institutional facilities, dearth of trained manpower, etc.
These problems are complicated and compounded with the occurrences ofregular and frequent disasters impeding the overall socio-economic
development efforts of the country. Exploring the historical disasterdatabase one can imagine the damages that occurred due to naturalcalamities.
Creating hazard maps will assist us to determine which areas are
susceptible to individual hazards or multiple hazards that have been
identified. The appropriate decision makers can use maps that depict
individual hazards or a combination of hazards. This study identified district
wise natural hazards, their hazard risk and finally developed combined
hazard map. The multi-hazard maps determine which areas are susceptible
to the most destructive hazards in order to determine where to concentrateand fund hazard mitigation measures such as developing property protection
ordinances or encouraging development in less hazard-prone areas.

2. METHODOLOGY
In order to locate highest-risk areas, it may be helpful to first develop a riskprioritization scheme. It is possible to develop such a scheme using publicly
available data, although local data — data collected from local agencies —will almost always be more detailed and more accurate. In this study
following natural disasters were studied:• Tornado• Earthquake• Cyclone• Flood
Every community have unique or unusual hazards that need to beconsidered. Historical records and information from local experts andcitizens is used to provide estimates of the zones or locations potentially atrisk to such events. As no digital (geographic information systems or GIS)
data are available for Bangladesh, it has to construct risk maps showing
estimates of hazard extents and magnitudes by using transparencies overlaid
on paper maps. Even some paper maps have to be modified to gather data.
Following steps were followed for hazard assessment of each district area of
Bangladesh:
1. Locate, gather, and process data
2. Assign scores to risk areas (higher rankings should indicate higher
risk)
3. Identify high-risk locations (areas with highest scores)
4. Propose a multi hazard map for Bangladesh

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2.1

Data Sources

The data were collected from Bangladesh Meteorological Department(BMD), SPARRSO, Disaster Management Bureau (DMB) and concerned
non-government organizations (NGO), Cyclone Preparedness Programme(CPP), geological information from the Geological Survey of Bangladesh(GSB). Information from local and environmental organizations,international Journals, local newspapers and many study reports werecollected. Personal contacts with experts concerned were also made.
2.2

Hazard Area Scoring Methods

Assign scores within risk areas, where possible. Within risk areas
there could be additional boundaries representing varying degrees of risk.
These varying degrees of risk should be represented in risk areas bothgraphically (additional boundaries on the maps) and through some type of
relative scoring system (higher scores for higher risk areas). For example,
Cyclone maps are generally created for five different categories of storm.
Category 1 storms are generally associated with the least severe winds andstorm surge while Category 5 storms are considered the most severe forthese hazards. Generally, those areas subject to storm surge in the lower
category storms are also projected for inundation in all of the higher
categories. When developing a relative priority scoring system for storm
surge inundation, Category 1 storm surge areas would therefore have thehighest risk of being flooded since they are at risk of inundation in all storm
events.
The general concept in relative priority scoring system for natural
hazard risks is that locations with no consideration for risk will be given ascore of 0 and each incremental increase in risk adds 1 point. A multiplier orweighting factor is calculated based on frequency of events (NOAA, 2007).
2.3

Concept of Hazard Affected Frequency

Frequency is the occurrence of a disaster in a particular area. To
explain this issue for a particular disaster, occurrence of flood in a particulararea per year can be used.
Estimated flooded areas for September 18, 1988, October 31, 1995,
and September 18, 1998 are 34.7, 27.7 and 36.1%, respectively, when thedrainage network map was superimposed onto the flood season images.
Figure 1 shows the concept of the frequency (Islam and Sado, 2000). The
flooded area was estimated after subtracting the normal water area (river,lake, pond, etc.) from total inundated area; it was then converted topercentage of land area (non-water area in dry season) of the whole country.

Vulnerability Risk Areas of Bangladesh Due to Multiple Natural Hazards

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Figure1: Concept for flood-affected frequency (after Islam and Sado, 2000)
The more occurring number indicates more frequency that isexpressed by multiplier for a particular risk area for a particular hazard.
2.4

Relative Priority Scoring System for Natural Hazards

For a particular area for the various hazards scores are calculated asfollows:
Risk Score (for particular hazard e.g. Cyclone/ Flood/ Tornado/
Earthquake) = Weighting factor (WT(fr)) × Risk ( Potential Damage
Magnitude).
TR (c/ f/ t/ e) = WT (WT =f (fr)) × R ……………...……….(1)For Cyclone:
Rci = f ( w, h, cp)
Where i= 0, 1, 2, 3, 4, 5.
w= Wind speed, h= Storm Surge, Cp= Central Pressure.
WTcj = f (fr)fr = Frequency.
Where j= 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
TRc= Rci × 0.1WTcj…………………………………….(2)For Tornado:
Rti = f ( w)544

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Where i= 0 and 5.
w= Wind speed.
WTtj = f (fr)fr = Frequency.
Where j= 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
TRti= Rti × 0.1WTtj ……….………………………. (3)For Flood:
Rfi = f (hw)
Where i= 1, 2, 3, 4, 5.
hw= Water level.
WTfj = f (fr)fr = Frequency.
Where j= 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
TRti= Rti × 0.1WTfj .……………………………….(4)For Earthquake:
Rei = f (m, p)
Where i= 2, 3, 4.
m = Magnitude, p= Peak Ground Acceleration.
WTej = f (fr)fr = Frequency.
Where j= 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
TRei= Rei × 0.1WTej .………………………………….(5)Total Risk Score:n
TR= ∑ TRk ………….…………………………………………… (6)
k=1
where
k= 1 is for Cyclone.
k=2 is for Tornado.
k=3 is for Earthquake
k=4 is for flood
k=n disaster.
In these equations, two of the hazards have locations with a risk scoreof 0 (Cyclone and Tornado). In case of Cyclone, the maximum extent of thehazard risk does not realistically include the entire county and is limited toproximity to coastal waters. Tornado may always have high risk, i.e score 5
for all the tornado prone area. For the locations with no consideration of risk
for Tornado was given a score of 0. Again earthquake hazard of Bangladesh
was expressed as minimum by 2 and as maximum by 4.
The minimum risk score for each of the remaining hazards is 1 since
there is some potential that each of these hazards could occur anywhere
throughout each county. This scoring system has been used according to our

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district-based database. For particular district of Bangladesh the hazard for
Earthquake, Tornado, Cyclone and Flood is calculated. Then adding thosescores, total risk score for each of the 64 districts was found.

3. LOCATING THE HAZARD
3.1

TornadoThe existing tornado map of DMB, GoB (DMB, 1993), is shown in
Figure 2. In the map the areas affected by Tornadoes are identified. The
basis of this map is not clear. For this study a new tornado map is digitised
based on frequency or number of occurrence from the compiled database,which contains Tornado data from 1875-2007. From the database, thefrequency of the tornado is calculated by the occurrence of Tornado. The
proposed digitized district wise Tornado map is also shown in Figure 2.
Bangladesh is divided into four zones as shown in Figure 2 and Table 1.

DMB
Map(1993)

SL.
No.
1.
2.
3.
4.
3.2

Proposed Map
Figure 2: Tornado Hazard Maps of Bangladesh
Table1: Risk vulnerability Table for Tornado
Area
Occurrence/Frequency
Severe Tornado Prone Area
>4
Moderate Tornado Prone Area
3-2
Tornado Prone Area
1
Non Affected Area

0

Risk Score
50

Earthquake

The peak ground acceleration (PGA), i.e., maximum acceleration
experienced by the ground during shaking, is one way of quantifying theseverity of the ground shaking. Approximate empirical correlations are546

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available between the MM intensities and the PGA that may be experienced
as Table 2 (Bolt, 1993).
MMI
PGA(g)

Table 2: PGAs during shaking of different intensities
V
VI
VII
VIII
IX
X
0.030.060.100.250.50>0.60
0.04
0.07
0.15
0.30
0.55

The existing seismic zoning map (BNBC, 1993) and the proposed
Seismic-zoning map of Bangladesh proposed by Ansary and Sharfuddin(2001) is shown in the Figure 3.

BNBC (1993)

Ansary and Sharfuddin (2001)

Figure 3: Seismic Zoning Map for Bangladesh
Comparing the Table 2 and the seismic zoning map with different
Earthquake intensity, a Vulnerability Table for Earthquakes of Bangladesh
has been proposed in Table 3.
Table 3: Proposed Vulnerability Table of Earthquake for Bangladesh
Zone
Intensity EMS
PGA
Risk Score
SL.
No.
1.
Zone-1VI
0.075g2
2.
Zone-2
VII
0.15g
3
3.
Zone-3
VIII
0.25g
4
3.3

CycloneFrom the cyclone affected area map of Bangladesh prepared by
SPARRSO, a cyclone risk map of Bangladesh was developed which isshown in Figure 4.
Comparing with the Saffir-Simpson Hurricane Intensity Scale with thedamage database of Bangladesh (LGEB, 1991), a cyclone risk area map for
Bangladesh was proposed as shown in Table 4.

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Figure 4: Cyclone Hazard Map of Bangladesh

SL
No

Table4: Cyclone Risk Area of Bangladesh
Risk Area
Category with storm surge

1.

High Risk Area

Storm surge
Above 1m

2.
3.
4.

Risk Area
High Wind Area
Non Affected Area

Below 1m
Storm Surge buffer-

3.4

Category
Category 4 and 5
Category 3
Category 2&1
-

Risk
Score
5
4
3
2
1
0

Flood

1998 flood is the extreme flooding of Bangladesh. The 1998 flood
hazard map prepared by FFWC, BWDB Dhaka, has been used as areference. According to the hazard map the whole area is divided in fourzones based on water level. The map is shown in Figure 5. Table 5 showsdifferent flood level of Bangladesh.
The damage risks for flooding have been developed by the
Vulnerability Atlas of India (BMTPC, 1997) based on material behavior
under submergence. Comparing with flood water level of Bangladesh with
the Vulnerability Atlas of India, a flood risk table for Bangladesh was
proposed as shown in Table 6.

SL.
No.
1.
2.
3.
4.

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Table 5: Flood Water level of Bangladesh
Area
Water Level
Severe Flooding Area
Moderate Flooding Area
Normal Flooding Area
Non Flooding Area

Above 50cm DL
Up to 50cm above DL
Within 50cm DL
Below 50cm DL

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Figure 5: Flood Hazard Map of Bangladesh

SL.
No.
1.

2.
3.
4.

3.5

Table 6: Flood Risk Table for Bangladesh
Area Type
Water
DamageLevel
Type
SevereAbove
Very High Damage Risk
Flooding Area 50cm D.L (>3m above D.L)
High Damage Risk(<3m above 50cm D.L)
Moderate
Up toModerate Damage Risk
Flooding Area 50cm
Above DL
NormalWithinLow Damage Risk
Flooding Area 50cm DL
No
BelowVery Low Damage Risk
Flooding Area 50cm DL

Risk
Score
5
4
3
2
1

District wise Risk Scores

Total Risk Scores for each of 64 districts were estimated following theabove methods. Table 7 summarizes the total risk scores for Districts of
Bangladesh.
From the above Table a district risk-ranking map for Bangladesh is
proposed which is shown in Figure 6. This map indicates the risky districtsof Bangladesh for multi hazard (Cyclone, Flood, Tornado and Earthquake).
This Figure shows risk scenario of Bangladesh at a glance.

Vulnerability Risk Areas of Bangladesh Due to Multiple Natural Hazards

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December 2007, Dhaka, Bangladesh

Sl.
No.
1.

2.

3.

Table7: Hazard Index and Risk Score
Hazard Total
Hazardous Districts
Index
Risk
Score
High
20-30
Dhaka, Bogra, Sirajganj, Feni, Comilla,
Cox’s bazaar, Lakshmipur, Noakhali,
Chittagong,
Tangail,
Mymensingh,
Kishoreganj, Jamalpur, Rangpur, Bhola,
Barishal, Kurigram, Gaibandha
Moderate 10-20
Sylhet, Gazipur, Manikganj, Narsingdi
Narayanganj, Munshiganj, Netrokona,
Sherpur, Gopalganj, Rajbari, Shariatpur,
Madaripur,
Sunamganj,
Pabana,Bandaban, Faridpur, Naogaon, Natore,
Nawabganj, Rajshahi, Brahmanbaria,
Joypurhat,
Chandpur,Lalmonirhat,
Nilphamari, Dinajpur, Magura, Khulna,
Satkhira, Bagerhat, Jessore, Panchagarh,
Meherpur, kushtia, Habiganj, Narail,
Moulvibazar,
Potualkali,
Pirojpur,BorgunaLow
1-10
Jhalkati,
Chuadanga,
Rangmati,
Thakurgoan, Khgrachari, Jhenaidah

Figure 6: Risk Hazard Map of Bangladesh
4.

PROPOSED MULTI HAZARD MAP OF BANGLADESH

Again from the individual digitized maps of Bangladesh for different hazard(Cyclone, Flood, Tornado and Earthquake) and superimposing those, amulti hazard zonation map for Bangladesh is prepared as shown in Figure 7.
From this map one can easily identify the hazard area with the hazard typeand intensity. This map is comprehensible to everybody.

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For identifying multihazard in a district more clearly, the multihazard
map of Chittagong District is shown in Figure 8. Table 8 provides
explanation for Figure 8.

Figure 7: Proposed Multi Hazard Zonation Map of Bangladesh

Figure 8: Proposed Multi Hazard Zonation Map of Chittagong
Table 8: Explanation of the multi hazard zonation map of Chittagong
SL. NO.
CODE
Explanation
1.
Z(TP_EZ2_CHR_FM) Zone: Tornado Prone Area
Earthquake Zone 2=0.15g
Cyclone High Risk Area
Moderate Flooding Area2.
Z(TP_EZ2_CHR_FL) Zone: Tornado Prone Area
Earthquake Zone 2=0.15g
Cyclone High Risk Area
Low Flooding Area
3.
Z(TP_EZ2_CHR_FN) Zone: Tornado Prone Area

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December 2007, Dhaka, Bangladesh

SL. NO.

CODE

4.

Z(TP_EZ2_CR_FS)

5.

Z(TP_EZ2_CR_FM)

6.

Z(TP_EZ2_CR_FL)

7.

Z(TP_EZ2_CR_FN)

8.

Z(TP_EZ2_CW_FS)

9.

Z(TP_EZ2_CW_FM)

10.

Z(TP_EZ2_CW_FL)

5.

Explanation
Earthquake Zone 2=0.15g
Cyclone High Risk Area
Non Flood Affected Area
Zone: Tornado Prone Area
Earthquake Zone 2=0.15g
Cyclone Risk Area
Severe Flooding Area
Zone: Tornado Prone Area
Earthquake Zone 2=0.15g
Cyclone Risk Area
Moderate Flooding Area
Zone: Tornado Prone Area
Earthquake Zone 2=0.15g
Cyclone Risk Area
Low Flooding Area
Zone: Tornado Prone Area
Earthquake Zone 2=0.15g
Cyclone Risk Area
Non Flood Affected Area
Zone: Tornado Prone Area
Earthquake Zone 2=0.15g
High Wind Area
Severe Flooding Area
Zone: Tornado Prone Area
Earthquake Zone 2=0.15g
High Wind Area
Moderate Flooding Area
Zone: Tornado Prone Area
Earthquake Zone 2=0.15g
High Wind Area
Low Flooding Area

CONCLUSIONSThis paper proposes a multihazard Map of Bangladesh based on a recently
compiled disaster database. For this purpose initially Tornado, Earthquake,
Flood and Cyclone zonation maps were reviewed and updated. This
multihazard maps will be used for policy makers to take decision fordisaster management and preparedness.

REFERENCES
Ansary M. A. and Sharfuddin, M., 2001. Proposal for a new seismic zoning
map for Bangladesh, Journal of the Civil Engineering, IEB, No. 30(2),pp. 77-89.

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BMTPC, 1997. Vulnerability Atlas of India 1997, Building Materials andTechnology Promotion Council, Ministry of Urban Development,
Government of India, New Delhi.
Bolt B.A., 1993. Earthquakes, W.H. Freeman and Co., New York, USA.
DMB, 1993. Natural Hazard Mapping, GoB.
EIA, 2004. Environmental Informatics Archives, Volume 2 (2004), 855-863,
EIA04-085, ISEIS Publication #002, © 2004 ISEIS - International
Society for Environmental Information Sciences.
Hossain A. N. H, 2006. An Overview on Impacts of Flood in Bangladesh
and Options for Mitigation.
Islam, M. and Sado K., 2007. Flood Hazard Assessment for theConstruction of Flood Hazard Map and Land Development Priority
Map Using NOAA/AVHRR Data and GIS - A Case Study in
Bangladesh, Department of Civil Engineering, Kitami Institute ofTechnology, Japan .
Karim A.K.M, 1996. Formation of Planning and Land-Use Policies for
Disaster Management in Chittagong Metropolitan Area of
Bangladesh, UNCRD-BUET Joint Research, Department of Urban
and Regional Planning, BUET, Bangladesh.
LGEB, 1991. Cyclone damage-1991, Damage Assessment of General
Infrastructure, Local Government Engineering Bureau, Final Report,
Volume 4, The world Bank, GoB.
NOAA Coastal Services Center, 2007. Risk and Vulnerability Assessment
Steps, Hazards Analysis Extended Discussion.
Oldham, T. 1899. Report on the great India earthquake of 12th June, 1897,
Memoir of Geological Survey of India, Vol. 19, 1-53.

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December 2007, Dhaka, Bangladesh

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PROPOSAL OF INTENSITY SCALESFOR DIFFERENT NATURAL HAZARDSIN BANGLADESH
MUSA. SHAMMI AKTHER
Graduate Student, Department of Civil Engineering, BUET, Bangladesh
shammii_bd@yahoo.com
MEHEDI AHMED ANSARY
Professor, Department of Civil Engineering, BUET, Bangladesh
ansary@ce.buet.ac.bd
ABSTRACTThis paper covers topics related to hazard intensity scales for natural
disasters like Earthquake, Flood, Cyclone and Tornado for Bangladesh. It
also summarizes district-wise housing risk tables based on Earthquakes,
Cyclones, Tornados and Floods. All these analyses will be useful toengineers, planners, emergency personnel, government officials, andagencies that may be concerned with hazard mitigation activities in a given
region. It will be helpful also to people who will be directly affected by thenatural disasters. Secondary data and information was collected from thecensus report as well as various government and non-governmentorganizations such as Bangladesh Meteorological Department (BMD),SPARRSO, Disaster Management Bureau (DMB) and concerned nongovernment organizations (NGO). For different intensity scale, different
models were used. Intensity scales for different disaster of Bangladesh areproposed based on disaster data and worldwide disaster intensity scales.
Finally using the census attribute data of housing of different district ofBangladesh a Housing category Table for intensity scales of disaster was
prepared.

1. INTRODUCTION
Natural processes such as tropical Cyclones, Floods, Tornadoes, Earthquake,and the like are an enduring condition around the human environment.
Natural hazards become disasters when they intersect with the humanenvironment. In Bangladesh, natural disasters have left a profound imprintcausing devastating loss of life, property, economy and community.
Bangladesh is one of the most natural disaster prone countries in theWorld. Floods, cyclonic storms, tidal surges are the major disasters anddroughts, tornadoes, riverbank erosion, earthquake are other types ofdisasters in the country. All these disasters are occurring in Bangladesh
regularly and frequently. Intensity scales are subjective and depend uponsocial condition and construction status of a country, they need revisingfrom time to time. Regional effects must be accounted for. There exists no555

December 2007, Dhaka, Bangladesh

individual hazard intensity scale to identify the type of particular hazard for
Bangladesh. This paper studied different Bangladeshi disaster and theircorresponding scales all over the world, and proposed suitable intensity
scales for different disaster in Bangladesh.

2.

INTENSITY SCALES AND MODELS

2.1

Tropical Cyclones

Hurricanes, tropical storms and typhoons are collectively known as
tropical cyclones. These cyclones are defined as low-pressure areas ofclosed circulation winds that originate over tropical waters (FEMA, 1997).
Figure 1 shows the effect of a cyclone. Tropical storms have stained surface
wind speed that ranges from 39 to < 74 mph and that hurricanes have aminimum sustained surface wind speed of at least 74 mph.

Figure 1: Effect of a Cyclone
In Saffir-Simpson Hurricane Scale, a 1-5 rating based on a hurricane's
present intensity, used to give an estimate of the potential property damage
and flooding expected along the coast from a hurricane landfall. Wind speed
is the determining factor in the scale, as storm surge values are highly
dependent on the slope of the continental shelf in the landfall region.
Comparing with historical database with the Suffir-Simpson Hurricane
Scale and using STP model (Storm Track Prediction) of Cyclone, anintensity Scale for Bangladesh is proposed (Debsarma, 1988).
Also a Storm Surge Forecast (SSF) model (Debsarma, 1993) based onwind speed, central pressure and 200m bathymetric contour for Chittagong,
Cox’s Bazar, Kutubdia, Sandwip, Hatia, Khulna can be generated. Table 1
presents predicted highest storm surges for those areas based on the SSF
model.

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Table 1: Predictable Storm surge of Bangladesh by modeling
SL. Wind Expected Location
Storm Surge (m)No. Speed Central(kph) Pressure
Above tide Abovelevel
Mean Sea
Vmax (ECP)
level
1.

153

976

2.

177

966

3.

209

948

4.

220

942

5.

249

924

6.

>250

924

Chittagong
Cox’s Bazar
Kutubdia
Sandwip
Hatia
KhulnaChittagong
Cox’s Bazar
Kutubdia
Sandwip
Hatia
KhulnaChittagong
Cox’s Bazar
Kutubdia
Sandwip
Hatia
KhulnaChittagong
Cox’s Bazar
Kutubdia
Sandwip
Hatia
KhulnaChittagong
Cox’s Bazar
Kutubdia
Sandwip
Hatia
KhulnaChittagong
Cox’s Bazar
Kutubdia
Sandwip
Hatia
Khulna

3.04
2.28
2.59
3.12
2.98
2.61
3.93
2.97
3.36
4.03
3.86
3.38
5.25
3.98
4.50
5.38
5.15
4.52
5.73
4.35
4.92
5.88
5.63
4.94
7.08
5.40
6.09
7.25
6.95
6.12
7.13
5.43
6.13
7.30
7.00
6.16

6.62
4.54
6.21
7.61
6.75
5.53
7.51
5.23
6.98
8.52
7.63
6.30
8.23
6.24
8.12
9.87
8.92
7.44
9.31
6.61
8.54
10.37
9.40
7.86
10.66
7.66
9.71
11.74
10.72
9.04
10.71
7.69
9.75
11.79
10.77
9.08

Table 2 presents the proposed Cyclone Intensity Scales for
Bangladesh.
Bangladesh needs to develop a damage risk level table from previous
damage study. Due to limited data identification of the actual damage risk
level is not possible. So Saffir-Simpson Hurricane Scale with somemodification suggested by expert based on cyclone damage data of 1991
(LGEB, 1991) is adopted as shown in Table 3.

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December 2007, Dhaka, Bangladesh

2.2 Tornadoes
A Tornado is a rapidly rotating vortex of air extending ground-wardfrom a cumulonimbus cloud. Tornadoes can reach wind speeds in excess of
300 mph causing various intensities of destruction within its path. Often
tornadoes are related to larger vortex formations and as a result often formin convective cells. Figure 2 shows a twisting funnel of a tornado (CHCDA,2005).
Table 2: Cyclone Intensity Scale For Bangladesh
Scale
Number(Category)

ExpectedPressure(mbar)
1>=976
2966-9753948-9654923-947
5<924
ATL = Above Tide Level

Central Wind Speed

Maximum
possible Storm
Surge (ATL)

(in)

(mph)

(kph)

(m)

(ft)

>=28.9428.50-28.91
27.91-28.47
27.17-27.88<27.17

74-95
96-110111-130131-155>155

119-153154-177
178-209210-249>249<3.5
3.5-4.5
4.6-5.5
5.6-7.5
>7.5

<12
12-15
16-18
19-25
>25

Figure 2: The violent, twisting funnel of a tornado
Table 3: Details Cyclone Intensity Scale for Bangladesh
DamageIntensity
Risk Level
Very Low
DamageRisk (VL)
Category 1

Low
DamageRisk (L)558

Description
Winds 74-95 mph (64-82 knots or 119-153km/hr) - Storm surge maximum below 12 ft
above normal. No real damage to building
structures. Damage primarily to fishing boats,
trees near coastal. Some damage to poorly
constructed signs. Also, some coastal roadflooding and minor pier damage.

Winds 96-110 mph (83-95 knots or 154-177
Category 2 km/hr) - Storm surge may maximum 12-18 feetabove normal. Some roofing material, door, and

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DamageIntensity
Risk Level

Description
window damage of buildings. Considerable
damage to trees with some trees blown down.
Some fishing boat is missing. Considerable
damage to poorly constructed signs, and piers.
Small craft in unprotected anchorages breakmoorings.

Moderate
DamageRisk (M)Winds 111-130 mph (96-113 knots or 178-209
km/hr) - Storm surge may reach maximum 1618 ft above normal. Tin roof, wooden supports
blown off. Tin shed cottage industry totally
damage. Crack in wall and beam and floor
settled of some godown. Some structural
damage to small residences and utility buildings
with RCC roof and wall crack. Extensive
Category 3 damage to doors and windows of one storey
buildings and General damage of doorswindows of some two storey residentialbuildings. Some damage of boundary wall andsteel gate. Some retaining wall washed away andsome damage to toe of wall. Wooden jetty
totally damage. Some electrical works damage.
Major damage to lower floors of structures near
the shore.

High
DamageRisk (H)Winds 131-155 mph (114-135 knots or 210-249
km/hr) - Storm surge may reach maximum
within 18-25 ft above normal. More extensive
curtain wall failures with some complete roof
structure failures on small residences. Semi
pucca tin roof totally destroyed. Roofs blown
away and windows-doors damaged of dormitory
Category 4 and community centre. Single storey buildings
totally collapse. General damage to interior of
cyclone shelter. RCC pillars crack. Doors andwindows of two storey cyclone shelter destroy.
Complete roof failure of many residential andindustrial buildings. Trees and all signs areblown down. Major damage to lower floors ofstructures near the shore.

Very High
DamageRisk(VH)

Winds greater than 155 mph (135 knots or 249
km/hr) - Storm surge may maximum greaterthan 25 ft above normal. Complete roof failure
on many residences and industrial buildings.
Category 5
Some complete building failures with small
utility buildings blown over or away. All trees
and signs blown down. Severe and extensive
window and door damage. Stairs, auditorium

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DamageIntensity
Risk Level

Description
and toilet block severely damage. Some one
storey buildings and boundary walls collapse.
Some two storey buildings destroy.

The Fujita-Pearson Tornado Scale measures the damage severity of a
tornado. The historical data of Bangladesh is similar as the Fujita-Pearson
Tornado Scale. So for Bangladesh this scale can be adopted. The descriptionof this scale is given in Table 4 (FEMA, 1997).

Scale
Value
F0

Wind
Speed
(mph)
40-72

F1

73-112

F2

113-157

F3

158-206F4

207-260F5261-318

F6

>318

560

Table 4: Fujita-Pearson Tornado Scale
Intensity
Type of Damage

Light
DamageSome damage to chimneys; tree
branches broken off, shallow-rooted
trees pushed over, sign boards
damaged.
Moderate
Roof surfaces peeled off; mobile
Damagehomes pushed off foundations oroverturned; moving automobiles
pushed off roads.
Considerable Roofs torn from houses, mobile
Damagehomes demolished; boxcars pushedover; large trees snapped or uprooted;
light-object missiles generated.
SevereRoofs and some walls torn off wellDamage
constructed houses; trains overturned;
most trees in forest uprooted; heavycars lifted off the ground and thrown.
Devastating
Well-constructed houses levelled;
Damagestructures with weak foundations
blown off some distance; cars thrown;large missiles generated.
Incredible
Strong frame homes lifted off
Damagefoundations and carried considerable
distances to disintegrate; automobilessize missiles fly through the air inexcess of 100 yards; trees debarked.
Inconceivable These wind speeds have rarely been
Damagerecorded. The area of damage would
be completely obliterated andunrecognizable. Large missiles would
be thrown in excess of 100 yards.

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2.3

Flood

Flooding occurs in floodplains when prolonged rainfall over a shortperiod causes rivers or streams to overflow. Flash floods, specifically, occur
within six hours of a rain event, after a dam or levee failure or following asudden release of water held by a debris jam. In addition, development in
the flood hazard area can increase the overall height and speed of flooding
bringing it to areas that were not originally susceptible.

Figure 3: Typical Flood Damages
Depth classification maps rate also similar to flood depth maps, butinstead of using a constant depth increment for showing different depths,
depths are grouped into different classes. Depth classification maps can bebased on flood depth maps or duration depth maps. Figure 4 shows a depthclassification map based on the flood phase categories for the Tangail
compartment using the peak flood levels from the 1993 flood.

Figure 4: Depth Classification Map (after FAP25, 1994)

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December 2007, Dhaka, Bangladesh

Table 5 presents the Bangladesh flood phase classification, whichgroups flood depths into five classes, F0 to F4 (FAP25, 1994):

SL. No.

Table 5: Bangladesh flood phase classification
Class
Flood Phase
Depth Range

1.
2.

F0
F1

Non-flood
Shallow Flood< 0.3m including flood-free ground0.3m to 0.9m

3.
4.
5.

F2
F3
F4

Medium Flood
Deep Flood
Very Deep Flood

0.9m to 1.8m
1.8m to 3.6m
>3.6m

No such data exists for whole Bangladesh. It is not possible for this study
to establish such table for whole Bangladesh. For proper identification of hazard
area such data of flood for whole Bangladesh is needed.
1998 flood is the extreme flooding in Bangladesh. The flood hazard map
prepared by FFWC, BWDB Dhaka, has been used as a reference. According to
the hazard map the whole area is divided in four zones based on water level asshown in Figure 5. Table 6 presents four flood water levels of Bangladesh basedon 1998 flood:

Figure 5: 1998 flood affected area

SL. No.
1.
2.
3.
4.

562

Table 6: Flood Water level of Bangladesh
Area
Water Level
Severe Flooding Area
Above 50cm DL
Moderate Flooding Area
Up to 50cm above DL
Normal Flooding Area
Within 50cm DL
No Flooding Area
Below 50cm DL

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No Detailed building damage reports under flooding was recorded so far.
Flood intensities in terms of depth of water velocity of flow or time duration ofinundation are not yet defined. In the absence of such data, no definite
recommendation about damage risk levels could be made.
The following damage risks have been drafted by the BMPTC (1997) todevelop the Vulnerability Atlas of India, based on understanding of material
behavior under submergence. Table 7 is used for the intensity of Bangladesh.
Comparing the above tables and our historical damage data a intensity table for
Bangladesh is proposed as shown in Table 8. If our topographical data, floodlevel of whole Bangladesh in different flood year, the flood velocity zone etc.
are available than it can be made more accurate.
Table 7: Damage Risk Table for Flood
Sl. No. Damage Type
Description
1.

2.

3.
4.
5.

Very High
Damage Risk
(VH)

Total collapse of buildings; roof and some walls
collapse; floating away of sheets, thatch, etc;
erosion of foundation; severe damage to lifeline
structures and systems.
High Damage
Gaps in walls; punching of holes through wall by
Risk (H)flowing water; parts of buildings may collapse;
light roofs float away; erosion of foundation,sinking or tilting; undercutting of floors, partial
roof collapse.
Moderate Damage Large and deep cracks in walls; bulging of walls;
Risk (M)loss of belongings; damage to electric fittings.
Low Damage
Small cracks in walls; fall of fairly large pieces of
Risk (VL)
plaster.
Very Low
Fine cracks in plaster; fall of small pieces ofDamage Risk (L) plaster.

SL. No Area
Type
1.
SevereFlooding
Area

Table 8: Flood intensity of Bangladesh
Water Damage
Description
Level Type
Very High Total collapse of buildings; roof
Damageand some walls collapse;
Risk (>3m floating away of sheets, thatch,
above DL) etc; erosion of foundation;
severe damage to lifelineAbovestructures and systems.
50cm High
Gaps in walls; punching ofDL
Damageholes through wall by flowing
Riskwater; parts of buildings may(<3mcollapse; light roofs float away;above
erosion of foundation, sinking
50cm DL) or tilting; undercutting of floors,partial roof collapse.

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December 2007, Dhaka, Bangladesh

SL. No AreaType
2.
Moderate
Flooding
Area
3.

4.

2.4

NormalFlooding
Area
No
Flooding
Area

Water
Level
Up to
50cm
Above
DL
Within
50cm
DL
Below
50cm
DL

DamageType
Moderate
DamageRisk
Low
DamageRisk
Very Low
DamageRisk

Description
Large and deep cracks in walls;
bulging of walls; loss of
belongings; damage toElectric fittings.
Small cracks in walls; fall of
fairly large pieces of plaster.
Fine cracks in plaster; fall ofsmall pieces of plaster.

Earthquakes

Earthquakes are geologic events that involve movement or shaking of
the earth's crust. Earthquakes are usually caused by the release of stresses
accumulated as a result of the rupture of rocks along opposing fault planes inthe earth's outer crust. These fault planes are typically found along bordersof the earth's 10 tectonic plates.
The areas of greatest tectonic instability occur at the perimeters of theslowly moving plates, as these locations are subjected to the greatest strainsfrom plates traveling in opposite directions and at different speeds.
Deformation along plate boundaries causes strain in the rock and theconsequent buildup of stored energy. When the built-up stress exceeds therocks' strength, a rupture occurs. The rock on both sides of the fracture issnapped, releasing the stored energy and producing seismic waves,generating an earthquake.

Figure 6: Effect of an Earthquake
Earthquakes are measured in terms of their magnitude and intensity.
Magnitude is measured using the Richter scale, an open-ended logarithmic scalethat describes the energy release of an earthquake through a measure of shock
wave amplitude. Each unit increase in magnitude on the Richter scalecorresponds to a 10-fold increase in wave amplitude. Intensity is mostcommonly measured using the Modified Mercalli Intensity (MMI) Scale. It is a
12-level scale based on direct and indirect measurements of seismic effects.
There is another seismic Intensity scale name Japanese seismic intensity Scale,564

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0-VII levels. The MSK 1964 intensity scale is more comprehensive anddescribes the intensity of earthquake more precisely. EMS 1998 is the updated
scale of MSK scale. In this study EMS 98(European Macroseismic Scale) wasused. Table 9 shows the different vulnerability class (ESC, 1998).
Table 9: vulnerability classes

The masonry types of structures are to be read as, e.g., simple stone
masonry, whereas the reinforced concrete (RC) structure types are to beread as, e.g., RC frame or RC wall.
2.4.1 Classification of damage
The way in which a building deforms under earthquake loading
depends on the building type. As a broad categorization one can group
together types of masonry buildings as well as buildings of reinforced
concrete as shown in Table 10 and Table 11.

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December 2007, Dhaka, Bangladesh

Table 10: Classification of damage to masonry buildings
Grade 1: Negligible to slightdamage(no structural damage, slightnon-structural damage)Hair-line cracks in very few
walls. Fall of small pieces ofplaster only. Fall of loose stones
from upper parts of buildings invery few cases.
Grade 2: Moderate damage(slight structural damage,moderate non-structural
damage)Cracks in many walls. Fall of
fairly large pieces of plaster.
Partial collapse of chimneys.
Grade 3: Substantial to heavy
damage(moderate structural damage,heavy non-structural damage)
Large and extensive cracks inmost walls. Roof tiles detach.
Chimneys fracture at the roofline; failure of individual nonstructural elements (partitions,gable walls).
Grade 4: Very heavy damage(heavy structural damage, very
heavy non-structural damage)
Serious failure of walls; partial
structural failure of roofs andfloors.
Grade 5: Destruction(very heavy structural damage)
Total or near total collapse.

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Table 11: Classification of damage to buildings of reinforced concrete
Grade 1: Negligible to slightdamage(no structural damage, slightnon-structural damage)Fine cracks in plaster over frame
members or in walls at the base.
Fine cracks in partitions andinfills.
Grade 2: Moderate damage(slight structural damage,moderate non-structural
damage)Cracks in columns and beams offrames and in structural walls.
Cracks in partition and infill
walls; fall of brittle cladding andplaster. Falling mortar from thejoints of wall panels.
Grade 3: Substantial to heavy
damage(moderate structural damage,heavy non-structural damage)
Cracks in columns and beamcolumn joints of frames at thebase and at joints of coupledwalls. Spalling of conrete cover,buckling of reinforced rods.
Large cracks in partition and infill
walls, failure of individual infill
panels.
Grade 4: Very heavy damage(heavy structural damage, very
heavy non-structural damage)
Large cracks in structuralelements
withcompression
failure of concrete and fracture of
rebars; bond failure of beam
reinforced bars; tilting ofcolumns. Collapse of a few
columns or of a single upper
floor.

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December 2007, Dhaka, Bangladesh

Grade 5: Destruction(very heavy structural damage)Collapse of ground floor or parts(e. g. wings) of buildings.

Definitions of quantity

2.4.2 Definitions of intensity degrees
Arrangement of the scale:a) Effects on humansb) Effects on objects and on naturec) Damage to buildings
The single intensity degrees can include the effects of shaking of therespective lower intensity degree(s) also, when these effects are notmentioned explicitly.
I. Not felta) Not felt, even under the most favourable circumstances.
b) No effect. c) No damage.
II. Scarcely felta) The tremor is felt only at isolated instances (<1%) of individuals at
rest and in a specially receptive position indoors.
b) No effect. c) No damage.
III. Weaka) The earthquake is felt indoors by a few. People at rest feel aswaying or light trembling.
b) Hanging objects swing slightly. c) No damage.
IV. Largely observeda) The earthquake is felt indoors by many and felt outdoors only byvery few. A few people are awakened. The level of vibration is notfrightening. The vibration is moderate. Observers feel a slight trembling or
swaying of the building, room or bed, chair etc.
b) China, glasses, windows and doors rattle. Hanging objects swing.
Light furniture shakes visibly in a few cases. Woodwork creaks in a few
cases.
c) No damage.

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V. Stronga) The earthquake is felt indoors by most, outdoors by few. A few
people are frightened and run outdoors. Many sleeping people awake.
Observers feel a strong shaking or rocking of the whole building, room or
furniture.
b) Hanging objects swing considerably. China and glasses clatter
together. Small, top-heavy and/or precariously supported objects may beshifted or fall down. Doors and windows swing open or shut. In a few cases
windowpanes break. Liquids oscillate and may spill from well-filledcontainers. Animals indoors may become uneasy.
c) Damage of grade 1 to a few buildings of vulnerability class A
and B.
VI. Slightly damaginga) Felt by most indoors and by many outdoors. A few persons lose
their balance. Many people are frightened and run outdoors.
b) Small objects of ordinary stability may fall and furniture may beshifted. In few instances dishes and glassware may break. Farm animals(even outdoors) may be frightened.
c) Damage of grade 1 is sustained by many buildings of vulnerability
class A and B; a few of class A and B suffer damage of grade 2; a few ofclass C suffer damage of grade 1.
VII. Damaginga) Most people are frightened and try to run outdoors. Many find it
difficult to stand, especially on upper floors.
b) Furniture is shifted and top-heavy furniture may be overturned.
Objects fall from shelves in large numbers. Water splashes from containers,
tanks and pools.
c) Many buildings of vulnerability class A suffer damage of grade 3; afew of grade 4. Many buildings of vulnerability class B suffer damage of
grade 2; a few of grade 3. A few buildings of vulnerability class C sustain
damage of grade 2. A few buildings of vulnerability class D sustain damageof grade 1.
VIII. Heavily damaginga) Many people find it difficult to stand, even outdoors.
b) Furniture may be overturned. Objects like TV sets, typewriters etc.
fall to the ground. Tombstones may occasionally be displaced, twisted or
overturned. Waves may be seen on very soft ground.
c) Many buildings of vulnerability class A suffer damage of grade 4; afew of grade 5. Many buildings of vulnerability class B suffer damage of
grade 3; a few of grade 4. Many buildings of vulnerability class C suffer
damage of grade 2; a few of grade 3. A few buildings of vulnerability class
D sustain damage of grade 2.
IX. Destructivea) General panic. People may be forcibly thrown to the ground.
b) Many monuments and columns fall or are twisted. Waves are seen
on soft ground.

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December 2007, Dhaka, Bangladeshc) Many buildings of vulnerability class A sustain damage of grade 5.
Many buildings of vulnerability class B suffer damage of grade 4; a few ofgrade 5. Many buildings of vulnerability class C suffer damage of grade 3; afew of grade 4. Many buildings of vulnerability class D suffer damage of
grade 2; a few of grade 3. A few buildings of vulnerability class E sustain
damage of grade 2.
X. Very destructivec) Most buildings of vulnerability class A sustain damage of grade 5.
Many buildings of vulnerability class B sustain damage of grade 5. Manybuildings of vulnerability class C suffer damage of grade 4; a few of grade
5. Many buildings of vulnerability class D suffer damage of grade 3; a few
of grade 4. Many buildings of vulnerability class E suffer damage of grade
2; a few of grade 3. A few buildings of vulnerability class F sustain damageof grade 2.
XI. Devastatingc) Most buildings of vulnerability class B sustain damage of grade 5.
Most buildings of vulnerability class C suffer damage of grade 4; many ofgrade 5. Many buildings of vulnerability class D suffer damage of grade 4; afew of grade 5. Many buildings of vulnerability class E suffer damage of
grade 3; a few of grade 4. Many buildings of vulnerability class F suffer
damage of grade 2; a few of grade 3.
XII. Completely devastatingc) All buildings of vulnerability class A, B and practically all ofvulnerability class C are destroyed. Most buildings of vulnerability class D,
E and F are destroyed. The earthquake effects have reached the maximum
conceivable effects.

3.

HOUSING IN BANGLADESH

The census of houses (Census, 1991), gives details of houses based onmaterials of construction for walls and roofs. Table 12 summarized thebuilding types in different category based on Census (1991). This grouping
for the whole Bangladesh can be identified by collecting the whole district
wise census report of Bangladesh. The census reports generally show the
Dwelling Households by Material of Wall and Material of Roof of the Main
Structure. The wall and roof combinations are categorized as sloping(Straw/Bamboo/Polythene, Tiles/C.I/Metal Sheet) and Flat (Cement). The
vulnerability of different categories of houses can be described according to
the intensity scales described in this paper.

Category A
Category B

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Table 12: Category of Housing in Bangladesh
A1.
Mud wall with all roofs sloping.
A2.
Unburnt Brick wall with all roofs sloping.
B1
Burnt Brick wall with sloping roof

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Category C

Category X

4.

B1

Burnt Brick wall with flat roof

C1.(a)

Cement Wall with sloping roof

C1.(b)C2.
X1.
X2.

Cement Wall with flat roof
Wood wall with all roof sloping
C.I/Metal Sheet with all roofs sloping
Straw/Bamboo with all roofs sloping

CONCLUSIONSThis paper is an observation of damage levels in Bangladesh due to multihazard (e.g. Earthquake, Tornado, Cyclone, Flood). An attempt was made toprovide individual intensity scale for different disaster, which occur in
Bangladesh. Proper identification of a disaster by intensity scale canprovides a more complete understanding of the dangers, thereby easing theinitiation of long-term measures within the context of overall development
plans for a region.
ACKNOWLEDGEMENT
The authors are grateful to Mr. Sujit Kumar Debsarma, Assistant Director,
Bangladesh Metrological Department who helped in analyzing the data.

REFERENCES
BMTPC, 1997. Vulnerability Atlas of India 1997, Building Materials andTechnology Promotion Council, Ministry of Urban Development,
Government of India, New Delhi.
BBS, 1991.Bangladesh Population Census 1991, December, 1992, Statistics
Division, Ministry of Planning, GOB.
CHCDA, 2005. Multi Hazard Mitigation Plan, Country of Hawaii Civil
Defense Agency, Country of Hawaii.
Debsarma, 1995. Storm Track Prediction (STP) Model, Storm Warning
Centre, Bangladesh Meteorological Department Agargaon, Dhaka1207.
ESC, 1998. European Macroseismic Scale 1998, European Seismological
Commission.
FEMA, 1997. Fujita-Pearson Tornado Scale.
FAP 25,1994. FPCO: Flood Modelling and Management, Final Report,
GoB.
LGEB, 1991. Cyclone damage-1991, Damage Assessment of General
Infrastructure, Local Government Engineering Bureau, Final Report,
Volume 4, The world Bank, GoB.

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SOME EMERGING HAZARDS INMETROPOLITAN CITIES OFBANGLADESH
K.M. MANIRUZZAMAN
Professor, Department Of Urban And Regional Planning, BUET
mzaman@urp.buet.ac.bd
MOHAMMAD AMINUR RAHMAN
Teaching Assistant, Postgraduate Programs In Disaster Management,
BRAC University
1. INTRODUCTION
Bangladesh has experienced more than its fair share of natural or humaninduced disasters. Floods, oceanic surges, storms have repeatedly ravaged
the country, and the people remain braced to face the next onslaught. But
when landslides triggered by incessant rain over a period of nearly six hours
killed more than 120 people in the port city of Chittagong on 6 June 2007,
most Bangladeshis were left awestruck. Bangladeshis are not familiar withlandslides, especially those that are serious enough to threaten human lives.
In a way, the rude awakening early that morning served as an omen of more
surprises that may lie in store in the form of unexpected hazards as rapid
urban growth and development test the limits of tolerance of nature andintroduce changes into the physical, social and economic landscape.
Changes brought about by the urbanization process are bound to
introduce new hazards and vulnerabilities. Urban areas have been called‘crucibles of hazards’ (Mitchell, 1999a). As Bangladesh attains a more
urbanized character, it is important to assess what other forms of hazards
may strike in future, and take necessary precautions accordingly.
Some of the possible emerging hazards are hydro-meteorological innature but brought about as a result of human interventions in nature. Others
are the effects of scarcity of resources and services to meet the demands ofthe burgeoning urban population. Some potential new hazards arise out of
the economic activities concentrated in or around urban areas. Yet others area result of the increased global connectivity of the metropolitan cities.

2. URBANIZATION IN BANGLADESH
Urbanization in Bangladesh is going on at a very high pace, driven mainly
by migrants from rural areas. In 1991, around a fifth of the population lived
in urban areas. The share rose to a fourth in 2001 (BBS, 2001). Most of thisgrowth of urban population is absorbed by the capital followed at a distanceby Chittagong. Dhaka is experiencing a growth rate between 3 and 4 percent

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per annum. Around a tenth of the total population of Bangladesh and almost
40 percent of its urban population reside in Dhaka City. The frenzy ofgrowth and the tremendous pressure it puts on land in these two cities have
led to sound practices of planning and construction being flouted andignored. Resource-strapped city authorities are hard pressed trying to match
supply of services with rapidly expanding demand. One of the key
consequences of these is the rising threat of hazards that did not exist or
were infrequent so far.

3. URBAN FLOODING
The tragedy at Chittagong was a result of indiscriminate cutting of hills by
influential and unscrupulous businessmen, to make room for ‘development’
and to sell the soil removed from the hills, leaving portions of the hill
surface devoid of vegetation, often at a precariously steep slope. Under thecircumstances, landslides were inevitable. The destruction of hills also clogs
up the drainage channels with soil eroded from the hills raising the hazard ofurban flooding.
In Dhaka, where there are no hills, the pressure on limited buildable
land has resulted in the filling up of wetlands at the fringes andencroachment of waterways. Increased runoff and obstructed drainage
channels have exacerbated urban flooding. A few hours’ of rain, a common
phenomenon in the monsoon season, now inundate large tracts of the city.

4. BUILDING COLLAPSESThe rapid growth of urban economy and population has also resulted in arising tendency of shoddy construction. A large number of buildings in thecities are not designed or constructed by qualified professionals. High prices
of imported construction material motivate people to compromise withquality. Even in buildings erected by corporate bodies who employ
professionals, corners are cut in the haste to maximize returns at the cost of
structural quality. A number of buildings in Dhaka have collapsed under
their own weights in the recent past. The Spectrum Garment building
collapse of April 2005 claiming 76 lives, and the Phoenix Garmentsbuilding collapse of February 2006 killing 22 persons are cases in point.
These incidents are stark warnings of what may happen when extreme
natural forces inevitably act simultaneously on the urban structures at somepoint in future.

5. SCARCITY OF WATER
Another form of looming disaster that can be seen on the horizon is the
scarcity of water, especially but not exclusively in Dhaka. The Dhaka Waterand Sewerage Authority (WASA) is unable to meet the current demand ofwater and the daily shortfall in supply is around 800 million liters and574

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increasing. Around 80 percent of the supply is extracted from undergroundwith deep tube wells. The rest comes from the rivers. Environmentalists
have been warning against excessive extraction of subsurface water, but thewater in the rivers around the city has become polluted beyond treatment ina viable manner. The sources of pollution are untreated sewerage, industrial
effluent and spills from marine vessels. Even the subsurface water is now
reportedly under threat of contamination from the surface. These are very
disturbing signs of an impending water crisis that would have far-reachingand disastrous consequences.

6. TOXIC SPILLS AND EXPLOSIONSAs industrialization takes place in Bangladesh, many of the hazards that theindustrial world has faced already are gradually beginning to appear in thiscountry. However, the safeguards against such hazards are not in place, soeven at a lower stage of industrialization, the vulnerability is still high.
Because of inadequate legal framework and lax supervision, the facilities
and process of storing and transporting hazardous material used in industry
are less than satisfactory and may lead to disastrous leaks, spills or
explosions. Ship breaking yards in Chittagong where scrapped ocean liners,
often allegedly containing toxic material, are torn down in primitive fashion
without safety precautions posing a constant threat of explosions and toxic
contamination.

7. EPIDEMICS
Cities with crowded living conditions and inadequate urban services havebeen breeding grounds of epidemics throughout history. The bigger cities in
Bangladesh fulfill both criteria and are susceptible to outbreaks of diseases
spread by water or pests, such as dengue fever, malaria, diarrhea etc. A
potentially more serious threat is the outbreak of newer diseases such as
Severe Acute Respiratory Syndrome (SARS) or Avian Flu. New diseases
may originate in one corner of the globe, but spread very quickly. As theglobalizing economy knits countries closer together, increased and more
frequent international travel makes it easier for such diseases to spread
across national boundaries to far corners away from the site of origin very
quickly. For example, a person travelling in China transported SARS to
Canada in less than 24 hours (Quarantelli, 2006). The spread of SARS
stopped in 2003 and Avian Flu has not attained serious proportions. But
there is every possibility that a future disease may be more virulent andlethal. Cities are gateways of international travel and therefore more
susceptible to diseases originating in a different region. The most importantinternational airports in Bangladesh are located in Dhaka and Chittagong
and the latter is the main seaport of the country. So these cities are thepoints through which such diseases may make an entry into the country.

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8. THE WAY FORWARD
In the face of the situation described above, what measures are being taken
and what further measures can be adopted? Bangladesh has a reasonably
good body of laws and regulations for protecting the environment. The laws
prohibit the cutting of hills and filling of water bodies. Much of the
weaknesses in the legal framework for regulating construction have also
been removed with the adoption of the Bangladesh National Building Code(BNBC) and the Building Construction Rules (BCR) for Dhaka
Metropolitan City. BNBC was formulated in 1993, but the official gazettenotification making it mandatory to follow the code was published in
November 2006. The Code has extensive provisions to ensure safety against
wind, fire and seismic hazards. The rudimentary Building Construction
Rules of 1996 was totally revamped for Dhaka City in April 2006. This setof rules incorporates a system of holding responsible designated technicalpersonnel for each phase of design, construction and occupation. The rules
not only attempt to assure quality construction, but also ensure that a higher
portion of lots is left without construction to reduce runoff and increase
recharging of underground water. Similar rules are now being prepared for
Chittagong City.
Dhaka Metropolitan Development Plan (1995-2015) has strict
directives against building construction in areas delineated as flood flow
zones and sub-flood flow zones (RAJUK, 1995). Dhaka WASA has been
conducting periodic drives to rid the canals in the city of illegal
encroachment. Projects to improve storm water drainage are being
implemented. NGOs like the Bangladesh Environmental Lawyers’
Association are taking to court organizations that defy the ban on filling up
water bodies. This has acted as a deterrent and several ‘land development’projects remain suspended. Tanneries in Dhaka, a major source of riverpollution, are being rehabilitated at a site away from the city where effluent
treatment plants will also be installed.
While Bangladesh has no dearth of legal tools to promote a safe
environment, the problem has been with enforcement. Apart frominstitutional issues such as poor resources, manpower and capacity, endemic
corruption has been a hurdle to enforcement of laws. Storage andtransportation of hazardous material is one area where laws may be revisedand updated. This is an issue that is becoming a matter of serious concern as
the country continues on its path to industrialization.

9. CONCLUSION
Bangladesh has earned international acclaim for different aspects of disastermanagement. However the experience and expertise of Bangladesh lies
mainly in dealing with hazards in rural areas. The need to improve
preparedness and capacity to meet growing and emerging hazards in urban
areas cannot be overemphasized.

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Further research is required to assess the degree to which cities can beaffected by various types of unprecedented risks such as those associatedwith climate change, new industrial chemicals or hybrid hazards thatcombine natural, technological and social risks (Mitchell, 1999b).

REFERENCES
BBS (2001) Bangladesh Population Census 2001: Preliminary Report,
Bangladesh Bureau of Statistics, Dhaka.
Mitchell, J.K. (1999a) (ed.) Crucibles of Hazards: Megacities and Disasters
in Transition, United Nations University Press, Tokyo.
Mitchell, J.K. (1999b) “Megacities and natural disasters: a comparative
analsysis”, GeoJournal, vol. 49, pp. 137-142.
Quarantelli, E.L. (2006) “The Disasters of the 21st Century: A Mixture ofNew, Old, and Mixed Types”, Preliminary Paper #353, Disaster
Research Center, University of Delaware.
RAJUK (1995) Dhaka Metropolitan Area Development Plan (DMDP),
Rajdhani Unnayan Kartripakkha, Dhaka.

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EARTHQUAKE PREPAREDNESSCOMBATS URBAN DISASTERS
WAHIDA BASHAR AHMED
ActionAid Bangladesh
wahida.ahmed@actionaid.org
ABSTRACT
ActionAid, an international non-government organization working in
Bangladesh in various development activities as a development partner ofthe government. ActionAid is doing earthquake preparedness activities inthe vulnerable earthquake zone in Bangladesh since the Borkol Earthquakeof 2003. As a part of these, ActionAid developed 250 community volunteers
to work with community in case of earthquake or other natural disasters.
This group received several skill development training as such first aid andsearch and rescue. This paper will state the effectiveness of their skills,
which already applied to the vulnerable community in need.
Chittagong, the second largest metropolitan city in Bangladesh was
having heavy rainfall from the early monsoon this year. The hilly city
experienced highest rainfall on 11 June and this made several sudden
landslides in the city. One of the big ones happened in Kusumbag area
where 11 houses were collapsed. ActionAid’s developed community
volunteers rushed to the spot quickly and started rescuing people. Theyreached there before the government’s search and rescue team reached. The
paper will show and analyze the effectiveness of developing community
volunteers and their interaction with community in need.
ActionAid developed 200 community volunteers from 6 vulnerable
wards of Chittagong City Corporation with aim to work with the community
in case of earthquake disasters. They have been provided complete training
on earthquake preparedness, participatory vulnerability analysis, first aid
and search and rescue.
The community as well as ActionAid found the volunteers proactive
just after two disasters, one was fire in slum and another one was landslides
in city. The paper will check the preparedness level of the volunteers, theiracceptance level to the community, their response initiative and thepossibility to work with their community in case of earthquakes and so forth.

1. INTRODUCTION
ActionAid is working in the field of disaster management in Bangladesh forthe last two decades. Both preparedness and response were included in
ActionAid’s intervention. After the Borkol Earthquake of 2003, AcionAid
started preparedness work on earthquake in Chittagong City area, which wasamongst the second level of vulnerable earthquake zone in the country. One

579

December 2007, Dhaka, Bangladeshof the most important components of earthquake preparedness program wasdeveloping community volunteers who can work for community in need ofdisaster and emergency intervention. The following section will illustrate
the development of community volunteers, their preparedness forearthquake; and how they intervene in other natural disasters for theircommunity.

2. DEVELOPING COMMUNITY VOLUNTEERS
Primarily 23 vulnerable wards in the city corporation of Chittagong wereselected to carry on earthquake preparedness work. Among them, six wards
were identified as most vulnerable. Community volunteers were selectedfrom these six words. Initial criteria for volunteer selection were that thevolunteer should come up from that particular community. They should
possess strong sense of community and should have acceptance within thecommunity. Total twenty groups of volunteers, each group comprised 10
volunteers, were selected. The selected volunteers have been provided
following trainings and orientations to make up their skills, upgrade theirattitude, sensitize on earthquake preparedness.
2.1

Foundation Training on Earthquake Preparedness

This was a comprehensive training specially designed for thevolunteers to orient them on basic factors of earthquake and earthquake
preparedness. They were also interacted on community responsibility,
volunteerism, roles and responsibilities of community volunteers. They
were oriented on damage and needs assessment and immediate reporting.
Though the training objective was to orient community volunteers onearthquake preparedness, it covered several other natural or man madedisasters that can hamper normal livelihood of community.
2.2

Training on Participatory Vulnerability Analysis

This was a field-based training with practical demonstration on
identifying community’s vulnerability. At one stage, community’s
recommendation is checked to overcome the possible hazard. By thisexercise, volunteers demonstrated their ability to analyze community’s
possible threat to natural disaster or physical vulnerability to a particulardisaster. They also learned the technique of bringing recommendations ofcommunity to the concerned public representatives or local administrations.
2.3

Training on First Aid

In the process of skill development of the volunteers, training on FirstAid was organized. The training covered primarily the casualty situationthat can be arising after earthquake or other natural disasters. Volunteers
acquainted with the skills of safely shifting of disasters victims to nearby
health care centers. They also learned the coordination techniques that canbe used in disaster situations.

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2.4

Training on Search and Rescue

This was the most important training directly related to volunteer’s
skill development in earthquake response. The training was designed
specially to meet volunteer’s need after earthquake situation. In thispractical training, volunteers demonstrated skill of rescuing victims fromhigh-rise infrastructure without any heavy equipment.

3. VOLUNTEER PARTICIPATION IN RESPONSE ACTIVITIES
Since there had been no big or devastating earthquake in Chittagong or
outside Chittagong for the last couple of years, volunteers could notdemonstrate their skills in earthquake situation. However, they demonstrate
in other disaster as they took part in some disaster emergency search andrescue or intervention activities initiated by themselves or ActionAid orother actors inside or outside Chittagong. The following two are worth
mentioning.
3.1

Fire Response

Fire became a sudden urban disaster that happened in various parts ofChittagong for the last couple of years. The following two cases are worth
to mention here as community volunteers actively participated in the searchand rescue and demonstrated their ability.
Fire Response in KTS Garments: On the evening of 23 February,
2006 KTS Garments Factory in Chittagong City got fire accident. It was a
big one killing 67 and injured 109. Community volunteers rushed the spot
immediately but at first they were forbidden to get entered for any searchand rescue work. Next morning they opened an information center on the
spot. They were collecting and providing information of the distressed totheir family members. They Deputy Commissioner of Chittagong
appreciated their effort and permit them to get inside the spot to take part insearch activity with the government team. They made a quick assessmentand opened some mobile medical camp with support of the local medicalcollege. They were able to make coordination with local government andother responding agencies. They conducted final assessment and took part in
response activities.
Fire Response in Boubazar Slums: Boubazar is a big slum in Bakolia
area in Chittagong City Corporation. A devastating fire broke out here at theearly morning of 6 March, 2007. It killed 21 and injured 40 others.
Community volunteers quickly rushed the spot and started rescuing people.
They brought injured people to Chittagong Medical College Hospital fortreatment. They established coordination with the district administration andwith all agencies who initiated response activities. They provide constantcare to the hospitalized victims. They conducted initial damage and needs
assessment survey and informed the concerned agencies for necessary
action. On the following day, they conducted detail assessment andEarthquake Preparedness Combats Urban Disasters

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December 2007, Dhaka, Bangladesh

requested for essential relief package distribution. With their active andenthusiastic participation, ActionAid did a huge relief package distribution
to the affected victims. They were well taken by the community andadministration as well. Their fruitful movement acquainted them within
their community and external stakeholders as well.
3.2

Landslide Response

Chittagong was having heavy rainfall for the early monsoon on 11
June 2007. Most of the part of the city gone under knee to throat heightwater in the early morning. The incessant rainfall caused several sudden
landslides in the city. ActionAid’s developed community volunteers quickly
rushed to some spots and started search and rescuing victims. One of their
responses in landslide disaster became widespread as they could rush the
spot before the government rescue team arrived. In fact, they were on the
spot named Kkusumbag before the landslide happened. ActionAid got thefirst message from its community volunteer in Kusumbag area while they
were in action. The reporter volunteer said,“We five volunteers were helping the waterlogged peoplein Kusumbag area from the morning to leave their houses
as most of them were drowning by heavy rainwater. We
started to work from the early morning as our residenceswere also in the same area. We learned from ActionAid’s
training that heavy rainfall may cause landslide in
Chittagong. Intact, we were motivating people to evacuate
their houses as the heavy rainfall was not stopping andlandslide may occur in any time. At about quarter to ten in
the morning, we heard a big bang followed by a hue andcry. A landslide happened just on the slopping of the hill.
We five quickly rushed near the collapsed houses. Oh, thecollapsed houses lost their sign of house, all were mud andmud. People were quite at a loss. We started pulling out thederbies with our hands. We asked the gathered people tohelp us. Just at this moment, I made a phone call mysupervisee organization to inform about the disaster andthey reported ActionAid at the same time. It was good that
we first started work to search and rescue the victims andthen informed our authorities. We could inform themwithin 20 minutes after the landslide happed.”
When the government’s fire brigade rescue worker came, thecommunity volunteers worked with them. They worked like a big
team.

4. ACCEPTANCE AND POSSIBILITY
Community volunteers made quick response to the mentioned urban
disasters. Though the primary objective of their development was that they582

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would respond in earthquake disasters, but they proved their ability torespond in any other disaster with the same skill they gained from several
training and orientation done by AcitonAid. They made their access within
their community. They were accepted by concerned stakeholders. Local
government also accepted their existence and appreciated their team workwith government rescue workers.
It is evident that community volunteers got skill to respond any sudden
disaster in their community. They took part in some other response
operation in some other parts of the country, outside their city. They are
confident about their capacity and ready to work with less supervision or
without supervision in any onset of disasters. So earthquake preparedness isready to combat with other urban disasters.

5. CONCLUSIONS
ActionAid developed the community volunteers to work with their own
community. They were supported to increase their disaster knowledge andimprove their capacity and skills to work in earthquake disasters. But it wasan added advantage that volunteers were demonstrating in other disaster
response within their same capacity. They are owned by their community.
They are ready to dedicate their service for their community.

REFERENCES
Several project papers and documents of ActionAid were used as reference.

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EARTHQUAKE PREPAREDNESSCOMBINED WITH COMMUNITY EFFORTS
MD. FAIZ SHAH
ActionAid Bangladesh
mdfaizshah@yaho.com
ABSTRACT
ActionAid is doing earthquake preparedness activities in thevulnerable earthquake zone in Bangladesh since the Borkol Earthquake of
2003. ActionAid initiated earthquake preparedness activities in Chittagong,geologically which is situated in the second most vulnerable zone of country.
Both institutional and community based preparedness programs wereconducted. Institutional based programs comprised: (a) School based
programs, (b) Hospital based programs, (c) Garments based programs and(d) Local Government Institution (Ward) based programs. All these
programs conducted orientation on earthquake and earthquake
preparedness, simulation exercise, sensitization of schoolchildren throughpuppet show and development of contingency plan. As a result, all theselevel of beneficiary got their disaster action plan at hand now with theknowledge of preparedness.
Community based activities covered (a) Community sensitization onearthquake through street drama performance, (b) Lokokendra member’sorientation on earthquake and other natural disaster preparedness, anddoing Participatory Vulnerability Analysis (PVA) exercise to identify the
local risks. This community came up with specific recommendation to
reduce their vulnerability and they submitted to local government.
ActionAid developed 250 community volunteers to work with
community in case of earthquake or other natural disasters. This group
received several skill development training such as first aid and search andrescue. This paper reviews the effectiveness of their skills, which can beapplicable to the vulnerable community in need.
Finally the paper presents the most important development of
ActionAid’s preparedness i.e. the development of Earthquake Vulnerability
Atlas (EVA). How the concerned stakeholders were sensitized and find the
EVA a good preparedness tool – is analyzed.

1. INTRODUCTION
ActionAid Bangladesh has been working in the disaster management sector
for more than two decades. During this time, AAB has gained a wealth ofexperience in the major challenges and crisis prevailing in the sector in
Bangladesh. Disaster is now one of AAB’s key areas of focus with a clear
link to ActionAid international strategy and disaster policy.

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December 2007, Dhaka, Bangladesh

2. EARTHQUAKE PREPAREDNESS ACTIVITIESEarthquake is a new phenomenon in the field of disaster in Bangladesh. The
country uses to have small to moderate earthquake every month. Especiallypeople in the southeastern hilly area and adjacent town like Chittagong, felt
the jolt almost everyday. The Borkol earthquake in 2003 was big enough toalert people of the area that they should think about the early preparedness.
Geologically Bangladesh government identified this part of the country as
second most earthquake vulnerable zone. Amongst the towns in the region,
Chittagong is the most densely populated, where urbanization is rapid, andland use pattern is diversified. A sudden big earthquake can toll a higher
casualty in Chittagong. ActionAid initiated earthquake preparedness
activities here to sensitize the community, to build their capacity, and tostrengthening institutional capacities.
2.1

Institutional Based Programs

Institutional based programs covered several institutions’preparedness activities. For example, Schools, Hospitals, Garments factories
and Ward office of local government was the primary stakeholders under
this program.
2.1.1 School Based Programs
Schools are such educational institutions where on an average 2001500 people stay during the daytime. The objective of school-based
program was to sensitize the students, teachers and local community onearthquake and earthquake preparedness, enhance their capacity on
evacuation, search and rescue and first aid. First, sensitization session onearthquake and earthquake preparedness was done for all teachers of aschool including members of school management committees and selectedstudents. Secondly, evacuation drill was exercised with the participation of
all students and teachers. By this exercise school recorded the average
evacuation time, identified and marked the safety places for evacuation,
demonstrated how to conduct search and how to rescue victims safely after
a devastating earthquake hits. After doing this program, every school
identified the need for a guided plan or preparedness plan, which may leadthem to work effectively for preparedness. They formed school disastermanagement committees with teachers and members from school
management committees, guardians and local community. In someparticipatory sessions, schools developed their emergency preparedness planor contingency plan for earthquake preparedness and real time evacuation.
ActionAid worked with 12 Schools in Chittagong City including
government, private and City Corporation owned. To sensitize the smallchildren on earthquake in an easy way, puppet shows were performed inevery school. Being sensitized most of the small children conveyed theearthquake message to their family members and local friends.

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2.1.2 Hospital Based Programs
Hospitals are also big public gathering places where 200-500 people
stay round the clock and another 500-1000 people gather in the daytime. A
sudden earthquake can collapse the hospital system. Hospital itself may bevulnerable. Generally, after a big earthquake, mass casualty situation may
arise and people will rush to nearby hospitals. Therefore, hospitals need to
be prepared to handle mass casualty situation. Under this program, fivehospitals were covered. Sensitization orientation session on earthquake andearthquake preparedness was conducted, hospital disaster management
committees were formed, conducted training on mass casualty management,
performed simulation exercise on evacuation and mass casualty
management, search and rescue and first aid. Triage system was also
introduced to the doctors. Hospitals also developed their own contingency
plans to prepare and work effectively for preparedness and handle masscasualty situation. Doctors and medical employees of ten health care centersof City Corporation were given sensitization orientation on mass casualty
management.
2.1.3 Garments Factory Based Programs
Garments Factories are gathering places of workers who arecontributing to the economic development of the country like Bangladesh.
Normally factory buildings were not constructed for this type of heavy use.
Earthquake shaking can collapse the infrastructure and cause casualty
situation, damage and fire. Real time evacuation was the objective of
garments based preparedness program. A sensitization session was done at
the beginning stating the necessity of such program for garments. Workers
took part in safety evacuation and marked the possible gathering places. A
disaster management committee was also formed and they developed their
preparedness plan or contingency plan.
2.1.4 Ward Based ProgramsWard Offices headed by Ward Commissioners are the lowest tire ofCity Corporations in metropolitan cities like Chittagong. They haveimportant role in disaster assessment and effective response with decisionmaking. They are supposed to form disaster management committees toperform their disaster activities effectively. This program supported them toform a balanced disaster management committee, orient the committee andhelp them to exercise coordination in pre and post disaster situation.
ActionAid worked in 23 vulnerable wards in Chittagong City. Among them,
most six vulnerable wards were covered by ward-based interventions.
2.2

Community Based Programs

Community based programs mainly focused the low-income urban
community in the city corporation area of Chittagong. The selected 23
vulnerable wards of Chittagong City Corporation were densely populatedwith old houses and infrastructures. People were not aware about their

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vulnerability in terms of possible casualty, obstacle for search and rescue
work, using open spaces for evacuation and managing fire outbreak.
2.2.1 Community Sensitization
To sensitize this community on earthquake, several street dramas havebeen performed. The performance made a direct interaction with community
people so that they can be sensitized individually on earthquake issues.
2.2.2 Community Sensitization through CBO
Several grouped community people were also covered by the program.
People in a vulnerable place formed local CBO named Lokokendara. They
have been introduced disaster issues and their vulnerability. They performed
participatory vulnerability analysis and came up with specificrecommendations. They submitted the result and recommendations to theconcerned local ward commissioner for taking necessary steps for safeguard.

3. EARTHQUAKE VULNERABILITY ATLAS (EVA)
One of the most important outcomes of ActionAid’s earthquake
preparedness activities in Chittagong was developing Earthquake
Vulnerability Atlas (EVA) for pre selected 23 vulnerable wards. The EVA
was developed by considering the vulnerability by geographic data forexample, pattern of land use, infrastructure, population and density, roadlinks etc. The EVA identified vulnerable structures that may be a threat inincreasing casualty, marked the narrow streets that may obstacle vehicle
movement, found possible landslide locations that may add newer casualty
and showed existing open spaces that can be used for evacuation places. The
EVA was validated in sessions with concerned Ward offices particularly
with the members of ward disaster management committees. Finally it washanded over to ward offices, Chittagong City Corporation and Chittagong
Development Authority. These organizations can further develop andimprove the atlas and use it as a reference.

4. COMMUNITY VOLUNTEERS
As community can identify their own vulnerability, they can also come ingreat help in times of disaster. It is evident in every disaster that community
offers their first help in real time of need for search and rescue andevacuation work. External support takes time to reach grass root community.
If the community knows their possible vulnerability, they can take possible
preparedness measures. So a community can be better prepared if they haveusable resource in disaster like work force like volunteers. Under the
program, AcionAid supported in vulnerable 23 wards to develop a group ofyoung, energetic community volunteers. ActionAid developed total 250
community volunteers most of whom are students. They were given
sensitization orientation on earthquake and earthquake preparedness.

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Community volunteers also conducted participatory vulnerability analysis
involving their neighbors and community. They have been provided skill
development training as such training on first aid and search and rescue.
They were also provided material for first aid and search and rescue. The
volunteers have proven their ability and demonstrated their skills tocommunity. Thus, they have made acceptability within their own
community and community possesses the feeling of ownership.

5. LOGICAL ANALYSIS
ActionAid had done preparedness programs for vulnerable institutions andconcerned communities. ActionAid’s role was like facilitator, identified theneed of the community, involve community participation in searching
results, making preparedness plan and recommendations. Institutions cameup with their own remedy for possible hazards. They are practicing what
they evolved. So institutions developed their preparedness. Community
related to each institution became the part of the whole effort. For example,
school’s preparedness efforts are supported by the members of school
management committees, guardians and students. Hospitals and garments
are also taking local community’s support in their preparedness activities.
Moreover, community volunteers made a tremendous access to their own
community and to these institutions. They are taking part in every
institutional preparedness practices. So they are mainly maintaining thebridge between community efforts and institutional initiatives.

6. CONCLUSIONS
ActionAid supported earthquake preparedness activities made a scope forcommunity’s participation. Institutions combining related community’spresence in regular practices. Community volunteers are combining
community with institutions. ActionAid believes if the practices can be
maintained and mainstreamed, it will combine community efforts in disastermanagement.

REFERENCES
Several project papers and documents of ActionAid were used as reference.

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SOCIO-ECONOMIC ANDENVIRONMENTAL ASPECTS OFDISASTER RISK REDUCTION
MANAGEMENT FOR SUSTAINABLE
DEVELOPMENT IN BANGLADESH
MURSHED AHMED
Director (Economics)
Bangladesh Water Development Board, Bangladeshmahmed_3ch@yahoo.com
ABSTRACTThe main theme of the paper is to provide guidelines for developing acomprehensive approach and appropriate methodology for the mitigation ofdisasters and the promotion of sustainable development. It aims at
designing strategies and plans for mitigating the impact of disaster onsocial and economic development. Due to the increase of development
works, population, rapid urbanization and industrialization with low
economic growth the risk and vulnerability of natural disasters is growing
in the Asia Pacific region. The main focus of this paper is on identifying andexploring the guiding principles for overcoming the affects of flood disasterand alleviation of their impact for sustained development of Bangladesh.
The major challenges are to overcome the urban flood and cyclone hazards
by building sustainable communities to live with risk. Historical time series
data and records of information provide a wide variety of premises tohandle the disaster issue but they are hardly amenable to realistic solutions
to the disaster problem nor the flood-prone areas can be changed into floodor disaster free areas in a cost-effective way. Keeping these natural forcesin perspective, a long-term disaster mitigation strategy has been tried to be
evolved on the basis of sound principles. Effective disaster risk management
must take into account not only technical and economic but also social,administrative, environmental, political and legal framework. The paperargues for a more holistic model within a risk management context toaddress issues of vulnerability. Any solution to be permanent andsustainable for disaster risk management calls for broad political and social
consensus enhancing national, regional and international cooperation.

1. BACKGROUND AND RATIONALE
Management of disaster is an emerging need and growing concern of Asian
region. The major development challenge in the 21st century is how toensure effective disaster management. Disaster can be sudden or slow in
onset. Sudden onset of disasters like flood, cyclone and storm-surge,
drought, river bank erosion and earth quake destroy the country’s
infrastructures, commercial and industrial activities and environment.

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Views expressed herein are exclusively author’s own and do not in anyway
reflect those of BWDB
Historical statistics suggest that Bangladesh is one of the most disasterprone country in the world with negative consequences of devastating
floods, cyclone induced storm surge flooding, river bank erosion, drought,
earthquake, groundwater mining, arsenic contamination, chemical
pollutants, urban pollution, fire and technological accidents. Although there
is limited resources for coping with such calamities, human societies havethe capacity to recognize the risks that would lead to manage them withappropriate interventions. It is well recognized fact that it is possible tominimize the destructiveness through mitigation, preparedness, emergency
response, rehabilitation and reconstruction.
The future population growth that is predicted in Bangladesh aredestined to become more densely populated and thus more vulnerable tohazards. Land use in urban and semi-urban areas need to be plannedcarefully to minimize the risk due to hazards while maximizing economic
development. Over exploitation of land combined with a lack of appropriate
mitigation measures will increase the severity of flash floods and thevulnerability to drought (WWC, 2003).
Demand for food is increasing because of growing population. Total
population of the country will increase from about 129 million to 181
million by 2025 and 224 million by 2050 (NWMP, 2002).
2. GEO-PHYSICAL SETTING
Bangladesh is located adjacent to seismic belt and one of the largest active
delta of the world having a flat topography with very low elevations whichis larger than 10 meters from mean sea level. Eighty percent of the country
is deltaic floodplains which is criss-crossed by about 230 rivers including 57
transboundary rivers of which 54 is shared with India and three with
Myanmar. The river system that flows through Bangladesh is the thirdlargest source of freshwater discharge to the world's ocean. Catchments areaof the three major rivers system of the Ganges-Brahmaputra-Meghna(GBM) region is about 1.72 million km2, 93% of which lies outside thecountry. Bangladesh, being a lower riparian country, does not have any
control on the flow of these rivers. In GBM region, particularly in
Bangladesh, water is distributed unevenly in space and time due tounilateral withdrawal of water by India. This spatial and temporal variations
in water distribution creates major concern in relation to water availability.
The conditions and challenges of water management in Bangladesh are two
folds; scarcity of water during dry season together with water quality
deterioration, ground water depletion, salinity intrusion and environmental
degradation and too much water during monsoon with devastating flood.

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3. MAJOR CHALLENGES
•
•
•
•
•
•

Lack of political will and political consensus.
Non- compliance of the international conventions on water sharing
Lack of legislative and administrative framework for resolution of
conflicts
Lack of conservation storage reservoirs in the Himalayas
Upstream river basin development beyond the border of the country
Inter-basin water transfer project/River-linking project of India

To overcome these problems Bangladesh has been persistently trying
to negotiate with India since long. But as yet it has not been possible toreach a satisfactory level of solution to the problem (Ahmed, 2007). These
challenges are posing threat for the sustainable management of water
resources and Poverty Reduction Strategies (PRS). The water resourcesharnessing and development projects undertaken by the riparian countries
could not resolve the problems. The structural measures in isolation done by
the respective countries is not the ultimate solution for basin management of
the common rivers. It will rather create a severe havoc until and unless the
problems are not addressed considering the common interest of the coriparian countries of the Asia-Pacific region.
The impact of climate change will be more vital to economy andsociety. The climate change will also affect flows in the transboundary
rivers. The Himalayan zone is the climate regulator and also water head of
the Indian subcontinent. The role of Himalayas is not only the source of allrivers, they are also the source of the ecological life of the whole region.
The problems of water of the Himalayas watershed are a major engineering
challenge which can be solved satisfactorily by applying the principles ofIntegrated Water Resources Management (IWRM). To address thechallenges the co-riparian countries should make a paradigm shift and movetowards IWRM approaches. The challenge therefore is to:• Incorporate risk management principles in water resources management• Prevent flood hazards turning into disasters• Increase multidisciplinary approaches in flood management• Improved information on integrated flood management approaches• Alleviate poverty through preventive and response strategies forvulnerable sections• Enhance community participation
Priority actions on the above issues are required for achieving thegoal-1 of the Millennium Development Goals (MDGs). Implementing
country level PRS will need coordinated regional approaches to attaining
region’s socio-economic challenges.

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4. CAUSES OF FLOODING IN URBAN AREAS
Major cities, towns and civilizations are located in floodplains and havegrown near to rivers and are vulnerable to flooding. Asian countries like
Bangladesh, India, Thailand, China, North Korea, South Korea, Philippines,
Malaysia and Indonesia has been inundated this year by unusually heavy
and widespread floods.Each and every flood plain is a potential risk area
and their intensive use for residential, commercial purposes has resulted in
the expenditure of extremely large sums of money for flood protection
measures in recent years. Despite the vast expenditures that have been madefor flood control works, loses from floods are increasing every year. Due toincrease in land price the low lands have been developed which greatly
reduced storage facilities for floodwater. Similarly encroachments intodrainage facilities increased flooding and water logging. Political leaders,
Civil society, City administrators, bureaucrats are responsible for giving
permission for land development in urban areas. Urban flood problem incontext of Bangladesh can be identified as
•
•
•
•
•
•
•
•
•
•

Unplanned housing defying the building codes
Impeded drainage and water logging
Over abstraction of ground water
Reduced ground water recharge
Ground water mining
Land subsidence
Population boom
Rural to urban migration
Siltation of rivers
Free flow of water

The major flood disaster that occurred in Bangladesh are delineatedbelow:
Table-1: Major Floods Affecting Bangladesh
Item
1988
1998
2004 2007
Inundated
AreaofBangladesh (%)
People Affected (million)
Total Deaths (people)
Livestock Killed (nos.)
Rice
Production
Losses(million tons)
Road Damaged (kilometers)
NumberofHomes
Fully/Partly
Damaged(million)
Total Losses (Tk billion)

60

68

38

30-42

45
2300
172000
1.65

31
1100
26564
2.06

36
14
750 1071
8318 40700
1.00
1.00

13000
7.20

15927
0.98

27970 31533
4.00
1.10

83

118

134

-

Source: Ministry of Fisheries and Livestock, ADB and World Bank
estimate.

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Different development partners provided their continued support services
during all natural calamities in the past extraordinary flood and cyclone of
1987, 1988, 1991, 1998 and 2004. Flood damage rehabilitation currently
constitutes about 80% of ADB’s lending under its emergency assistancefacility. ADB will adopt a pro-active approach to reduce the severe
economic and social costs of natural disaster by promoting the use of
combined structural and non-structural approaches to flood protection
including flood-risk insurance (ADB, 2003). It is expected that development
partners will further continue their positive cooperation and provide theirsupport in post flood rehabilitation of 2007 for restoring the vital physicaland economic activities of the country.
An outcome of the World Conference on Disaster Reduction held in Kobe,
Japan in January 2005 was the ‘Hyogo Framework for Action 2005-2015’.
This Framework calls for all countries of the world including Bangladesh tocommit: (DMB, 2005-06).
• To pursue an integrated multi hazard approach for sustainable
development to reduce the incidence and intensity of disasters.
• To place disaster risk at the centre of political and economic priorities.
• To integrate disaster risk reduction in development planning.
• To invest substantively in disaster preparedness.
• To enable civil societies actors and affected communities to strengthen
their resilience to disasters.
5. ISSUES TO BE CONSIDERED FOR COMPREHENSIVE PLAN
FOR DISASTER RISK MANAGEMENT• The objective of the plan based on the flood management strategy• Legislative and legal requirements and constraints for the flood plan
• General framework of methodology for formulation of the flood plan
including planning criteria• (e.g. Cost Benefit Analysis, Multi-Criteria Analysis)• Floodplain mapping to identify the physical location, extent and• characteristics of the area
• General setting of the planning area as per NWMP
• Flood hazard mapping both at Macro and Micro levels to determine
the severity,• frequency, duration and depth of flooding• Flood risk information and mapping, charts, profiles and graphs• Hydrological factors and Morphological Characteristics• hydrological/Hydrometeorological data for the determination offlood frequencies, depth, duration, timing and rapidity
 river water levels including mean & flood peaks
 sediment load including bed materials & suspended materials
 geo-morphological approach based on drainage basin hydrological and hydraulic situation of the basin• Comprehensive Flood plan and management aspects for flood loss
reduction works and measures• Structural measures:
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Development in Bangladesh

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





•

•
•
•
•

large-scale embankments on major rivers
river training and bank protection
urban flood protection and drainage
coastal embankments
dredging of major channels
desilting of dead khals and rivers for improved drainage
Non-structural measures floodplain zoning to reduce flood damage risks
 flood proofing measures afforestation data required for effective retarding of floods.
 monitoring system for the purposes of improved disasterwarning systems and forecasting better disaster preparedness
Economic, social, institutional and environmental conditions on
existing situations and projections for the future
Assessment of structural and non structural measures
Alternative solutions of structural and non structural measures
Ranking of strategies.

6. INTEGRATEDMANAGEMENTAPPROACHTODISASTER

RISK

Bangladesh Water Development Board (BWDB) under the Ministry of Water
Resources has the primary responsibility for formulating and executing theplan in flood-prone area. BWDB is responsible for water resourcesmanagement with allied organizations like Water Resources Planning
Organization (WARPO), River Research Institute (RRI) under the Ministryof Water Resources (MoWR). Institute of Water Modelling (IWM) andCentre for Environmental and Geographic Information Services (CEGIS)
established by GoB provide technical support and environmental
management respectively and functions under the aegis of MoWR. IWM
has been carrying out modelling activities for improved irrigation
management, flood management, flood forecasting, groundwater modelling,morphological assessment and prediction modelling etc. Technicalmonitoring of environmental parameters are being accomplished by BWDB,IWM, CEGIS. Bangladesh Meteorological Department (BMD), Space
Research and Remote Sensing Organization (SPARRSO). Water resources
modeling exercises will play vital role for prediction and optimization oftrans-boundary water resources. Bangladesh being a disaster prone country,
had to concentrate her efforts towards flood loss reduction measures byconstructing flood embankment, river training and channel improvement anddevelopment of an effective Flood Forecasting and Warning System. The
active means of flood management by storage reservoirs is not possible
within her territory. Non-structural measures such as flood forecasting andwarning is currently performed by the large scale infrastructure like Surface
Water Hydrology under BWDB, BMD and SPARRSO.

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There had been a renewed awakening nationally as well as internationallyover floods and cyclones in Bangladesh and their solution. These recent
catastrophic floods have caused a change the attitude of planners and decision
makers and the Government of Bangladesh has emphasized that acomprehensive national flood protection programme needs large project
aimed at controlling the high discharges that come from the upstream
catchment. The strategy is, therefore:i) to accord the highest priority to the need for an integrated approach
to flood managementii) to implement effective flood management programs with emphasison comprehensive multi sector water developmentiii) to strengthen riparian cooperation leading to a long lasting solution
Disaster Risk management in Bangladesh calls for efforts based onregional (international cooperation) and national (domestic policy)
approaches.
6.1

Regional approach (cooperation with upstream nations)

Projects based on international cooperation should be planned,
designed and implemented in the following three stages :Stage 1 : Collection of data from upstream areas to improve flood
forecasting and warning systems
Stage 2 : Development of plans to establish an effective flood
prevention capability by linking embankments with those in upstream areas.
This plan would include an appropriate river training programme.
Stage 3 : Reduction of peak flood inflows under long-term perspective,
through construction of dams in upstream areas, management of river basins
and afforestation.
6.2

National approach (domestic measures)

Within Bangladesh project should be planned, designed andimplemented in the following lines:• Construction of embankments, implementation of river training,partial dredging of major rivers, removal of silt from minor rivers anddistributaries, improvement of existing flood control and drainage
facilities, construction of distributary channels or drainage canals,
improvement of flood forecasting and warning systems, flood
protection and drainage in Dhaka, alleviation of drainage problems
caused by banking of roads and railways, controlled flooding ofpolders, construction of refugee areas, protection of residential areas
outside of embankments, amendment of laws concerning irrigationand drainage, reinstatement of river morphology surveys,
reestablishment of hydrology training institutes, afforestation,
preparation of topographical maps. All these activities need be
performed on sound participatory approach through mobilizing watersector institutions at the centres, middle and the peripheries• Researchers have pointed out any steps to control flooding shouldemphasise both the structural and non-structural methods. Flood
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management programmes will be effective only when the mainfeature of flood plains are considered. Effective flood management in
Bangladesh calls for regional cooperation involving various
development options.
Formulating solutions to flooding problems requires a comprehensive
understanding of the geologic settings of the region and a better knowledge ofhydrodynamic processes that are active in watersheds. Only solutions thattake into account the underlying long-term factors contributing to flooding
problems can prevail. Such contributing factors are as follows: unplanned
urbanization, soil erosion, local relative sea-level rise, inadequate sedimentaccumulation, subsidence and compaction of sediments, riverbed aggradation,and deforestation. Structural solutions, such as the building of embankments
along the rivers and polders in coastal regions in Bangladesh, will not solve
the flooding problems but will result in many adverse environmental,hydrologic, economic, ecological, and geologic consequences. Solutions toflooding problems can be achieved by adopting and exercising watershedscale best management practices that include : floodplain zoning, planned
urbanization, restoration of abundant channels and lakes, dredging rivers andstreams, increased elevation of roads and village platforms, efficient storm
sewer systems, establishing buffer zones along rivers, conservation tillage,
controlled runoff at construction sites, good governance, indigenous
adjustment of life-style and crop patterns, and improvement on flood
warning/preparedness systems.
The most cost effective and efficient way to disaster reduction andmanagement is a co-ordinated approach to the appropriate combination of
structural and non-structural measures. The optimum flood mitigation plan forany particular area of Bangladesh region should, therefore, contain several
elements of structural and/or non-structural measures. Accordingly, integrated
flood management aims to maximise the efficient use of flood plains while
minimizing the loss of life from flooding and has five key elements;• Adopting a best mix of strategies both structural and non-structural;• Managing the water cycle as a whole while considering all floods,
including both extremes;• Integrating land and water management, as both have impacts on
flood magnitudes and flood risks;• Adopting integrated hazard management approaches, taking into
consideration the risks due to all related hazards such as land slides,
mudflows, avalanches, storm surges and tsunamis;• Ensuring a participatory approach to develop a sense of ownershipand reduce vulnerability.
Suggested measures against water management issues and hazards ontrans-boundary basins are delineated in Table-2.

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Table-2: Development Opportunities and Potentials
Objectives
Diagnostic
Solutionsanalysis
Regional Economic ¾ Reduction of ¾ Flood management
growth anddamages due
modeling
Development
to floods,¾ Basin widestorm surges
managementetc.
¾ River basin planning¾ Reinforceme
using mathematical
nt of floodmodelliing
plains¾ River basin
management
management¾ Hydro power
development¾ Flood forecasting &warning system
Health outcome and ¾ Safe
¾ Water quality
Human development
drinking
monitoringwater¾ Managing surface¾ Sanitationand ground water¾ Drainage
quality for¾ Cyclonemainstreaming the/stormenvironment in thesurges etc.
water sector¾ Urban drainage
management
Ensure¾ Improve¾ Balancing supply
environmental
water quality
and future demandsustainability and¾ Strongly¾ Water quality
bio diversity
enforcemodeling
restoration andexisting¾ Capacity building
protection of ecolegislation
for integrated
systemrelated to
managementwater¾ Developing global¾ Environment
partnerships &al impact
promoting regional
assessment
co-operationand social
impactassessment¾ Preservationof theaquatic Ecosystem

IWRM through an Apex Body: River Basin Organization

ICUS Report 27

A disaster management model for Bangladesh and the way forward isshown in Figure-1.

Socio-Economic and Environmental Aspects of Disaster Risk Reduction Management for Sustainable
Development in Bangladesh

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Source: Ministry of Food and Disaster Management

Figure-1: A Holistic Disaster Management Model
Political Economy of Transboundary Water Management
GBM region have experienced long-standing historical disputes
around politics of water planning for their common river basins. This has
resulted in creating mistrust among the countries of the region. The co-basinstates have tried to resolve the disputes but unfortunately because ofregional and socio-political controversy these initiatives have largely failed.
This failure prevented to capture the great opportunity of social andeconomic development of the region. It calls for political consensus of theriparian countries. South Asian Association for Regional Co-operation(SAARC) is one of the best forum which could solve the water dispute. But
they did not heed to the riparian disputes and consequently the impassepersisted.
Freshwater quality and quantity issues are becoming serious and mostcritical challenges to the five basin countries. The major factors for
freshwater conflicts are human activities like high population growth,
agricultural development, rapid rates of industrialization, upstream
diversions and abstractions (Figure 2). These factors are affecting water
availability both quantitatively and qualitatively which ultimately leads towater dispute among the co-basin states. Human systems depend criticallyon the state of the environment. Climate change is expected to have a broad

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and extensive impacts on the land water system in Bangladesh. The threat ofclimate changes will become the major regional environmental concern inwater disputes in the coming years. There is already clear evidence of
escalating conflicts in different parts of the world centered around water
quantity and quality issues. While the water quantity crisis is well known in
the GBM region freshwater quality will become the principal limiting factor
for sustainable development. China for the first time publicly stated thatwater quality is now limiting economic development. (Stephen, T.T. 1999).

Figure 2: Factors of Freshwater Disputes

7. REGIONAL COOPERATION
Regional cooperation is an important driving force for solidarity in river
basin management. One of the options is augmenting the Ganges flows
through the construction of a reservoir on the Sunkosh River in Bhutan may
be explored. Likewise, the proposed Sapta Kosi High Dam on the Kosi river(a tributary of the Ganges) in Nepal could bring significant benefits to India,
Nepal, Bhutan and Bangladesh in terms of flow augmentation. Bangladesh
can collaborate with Nepal and India for the construction of this dam for
mutual benefits. Basin management in Nepal will conserve soil resources,
mitigate flood and augment dry season flow for the areas in the downstream.
On the other hand, from economic consideration, the development of theimmense hydro-electric potential in Nepal will not only boost up the Nepali
economy but can be a cheap source of energy for Bangladesh and India(Rahman, S.M.M et. al, 2003).
Establishing River Basin Organization (RBO) for such regional
cooperation in water sector at the macro-level is more essential to makemicro-level water resources management sustainable. Network of Asia
River Basin Organizations (NARBO) expects to enhance capacity for
IWRM, ensure sustainable use of water for effective implementation of
IWRM and conflict resolution (4th WWF, 2006). For developing andpromoting active collaboration SAARC can patronize the RBO as proposed
to harness the potential of the water resources of the GBM region.
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8. PRINCIPLESMANAGEMENT
•
•
•
•
•
•

OF

SHAREDWATER

RESOURCES

Act locally but think globally putting people at the centre
No harm principle: obligation not to cause significant harm (UN,2005)
Justice and Equity
Free flow of data and information
Notification concerning planned measures
Political and public awareness.

The convention on the law of the Non-Navigational Uses ofInternational Water courses provides the principles and rules to guide statesin negotiating future agreement on specific water courses. All states in the
GBM region could adopt and ratify the Convention for future conflict
resolution. The Convention was adopted by the United Nations General
Assembly on May 21, 1997, following years of work by the International
Law Commission, (UN,2005).

9. MULTIPURPOSE RIVER BASIN DEVELOPMENT
Multipurpose River Basin Development (MRD) is fundamental for efficientand dynamic exploitation of water resources over time for irrigation, flood
control, erosion prevention, fisheries, industrial water supply, navigationand hydropower generation (World Bank, 1994). The development plan,undertaken so far, had a dominant focus on a single purpose rather thanmultipurpose development objectives. MRD might be a catalyst for regional
growth and sustainable tool for socio-economic and environmental
development that will enhance the quality of life shown in Figure 3.

Figure 3: Dynamic and Efficient Exploitation of Water Resources
through MRD

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MRD concept has not yet been developed for various historical,
political and economic reasons. As a result its potential for economic
growth and environmental sustenance at the regional and sub-regional level
has largely remained unrealized. Although MRD is difficult foraccomplishment and full of challenges for Bangladesh alone, neverthelessmany problems can be solved with dynamic programming. MRD, aframework for sustainable water use for the countries with predominantly
transboundary rivers can help obtain consensus that will decide in aparticipatory way for undertaking development strategies and investment
plans.

10. VISION AND OUTLOOK FOR THE FUTURE
Bangladesh hopes to create a safer environment through effective disastermanagement , risk reduction management concept and sustainable
development. Bangladesh is the role model of cyclone and flood
management in the world. The World Meteorological Organization (WMO)
has a vision to provide world leadership and expertise in international
cooperation to contribute to the safety and wellbeing of the people
throughout the world and to the economic benefit of all nations. This vision
is being achieved through the strategy of improved protection of life andproperty through;• Reduction of the social and economic impacts of natural disasters• Increased awareness and preparedness of peoples and society• Improved safety of infrastructures• Reduced vulnerability of human life and property to water, weather
and climate related hazards.

11. RECOMMENDATIONS AND CONCLUSIONS
Recommendations for the Asia Pacific region cover a wide range of issues
that require accelerated actions in a concerted manner by strengthening andreinforcing, which are:
• Flood mitigation and drainage facilities should be major
determinants of design, planning and development of cities.
• Strong leadership, political commitment, formulation of relevant
rules, regulations, laws and principles are urgently needed to avoid
sudden release of water retained by constructing barrages on thetrans-boundary rivers by upstream countries.
• Regional cooperation on trans-boundary rivers should be ensured forfree flow of data exchange and sharing of experiences forforecasting flood incidence• Long-term research should be undertaken by the national, regionaland global experts for capacity building and transfer of latest
technology.
However, turning strategies into action will require the following steps:
Socio-Economic and Environmental Aspects of Disaster Risk Reduction Management for Sustainable
Development in Bangladesh603

December 2007, Dhaka, Bangladesh

To develop policy and operational frameworks for stronger
coordination, collaboration and information sharing and management acrossgovernment, development agencies, Universities, NGOs and enabling
communities for working together.
To establish and maintain strong regional cooperation and networks
and active contribution to national, regional and international urban disastermanagement agenda.
To pursue the standardisation of disaster management training andsystems to align with best practice standards, models and competencies.
To learn from technologically expertise experience and continuous
exchange of these experiences.
From the discussion above, it will help towards the achievement andattaining the MDGs of the countries uniformly embodying technologicalinnovations on water related hazards. The reality is that emphasis should beon getting the message right at all the various stages of disaster spectrum ina scientific way.
ACKNOWLEDGEMENTS
The author gratefully acknowledges institutional and support services
received from BWDB, Institute of Water Modelling (IWM), Centre forEnvironmental and Geographic Information Services (CEGIS), Bangladesh
University of Engineering and Technology (BUET) and South Asian
Disaster Management Centre (SADMC) of International University ofBusiness Agriculture and Technology (IUBAT), Dhaka.

REFERENCES
ADB,2003, The Water Policy of the Asian Development Bank, Publishedby ADB, June2003, P.20
Ahmed, Murshed (2007), Some Reflections on Multipurpose on River Basin
Development and Strategies for Achieving Sustainable Solutions inConflict Management of Water Resources, presented and published in
Pre-Conference Paper Volume on International Conference on Water
and Flood Management organized by IWFM of BUET, 12-14 March,
2007, Volume-2, Dhaka, Bangladesh. P.680
DMB, (2005-06), Disaster Management Bureau Strategic Plan, 2005-2006.
NWMP, (2002), National Water Management Plan, Ministry of Water
Resources, Government of Bangladesh, Volume-2, Main Report,
Dhaka 2002, P. 23
Rahman, S.M.M et.al (2003), Conflict management of international river
basins: A case study of GBM River Basins, presented in a Regional
Conference organized by BUET and sponsored by UNESCO, 2003. P3,17.
Stephen, T. T.(1999), et al, Water Quality Processes and Policy (ed.) P.9

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4th WWF, (2006), Fourth World Water Forum, Asia-Pacific Regional
Document, March 16-22, 2006, P. 58
The World Bank (1994), Multipurpose River Basin Development in China,
EDI Seminar Series, (ed.), Peter Sun, October, 1994, P.10.
UN (2005), The Convention on the Law of the Non-Navigational Uses ofInternational Watercourses 1997, Article 7, P.5.
WWC (2003), World Water Actions, Forum Edition, March 2003, P.71

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Development in Bangladesh

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URBAN ROAD SAFETY: EFFECTIVERESCUE OF ACCIDENT VICTIMS USINGGIS TECHNOLOGY
DR. MD. MAZHARUL HOQUE
Professor, Department of Civil Engineering,
Director, Accident Research Centre (ARC),
dirarc@arc.buet.ac.bd
KAZI MD. SHIFUN NEWAZ, S. M. SOHEL MAHMUD
Research Assistantshifunnewaz@yahoo.com; smsohelmahmud@gmail.com,
SABREENA ANOWAR, ARMANA SABIHA HUQ
Junior Research Fellow
Accident Research Centre (ARC),
Bangladesh University of Engineering & Technology (BUET),
Dhaka, Bangladesh
ABSTRACTWorldwide about 1.2 million people are being killed and up to 30-40
million people are injured or permanently disabled every year due to roadtraffic accidents. Almost half of this deaths and injuries take place in the
countries of Asia and the Pacific region. Whilst deaths are declining in thedeveloped world, significant increases are still taking place in the countries
of Asia, including Bangladesh. The rapid increase of urbanization andmotor vehicle ownership in Bangladesh in recent years in combination withthe wide mixing of vehicle types have resulted in the significant worsening
and further aggravating the road safety problems. About 50 percent of roadtraffic deaths happen within 15 minutes of accidents as a result of injuries tothe brain, heart and large blood vessels. A further 35 percent die in the next
1-2 hours of head and chest injuries, and 15 percent over the next 30 days
from sepsis and organ failure. After an accident on crowded street of cities,
it is difficult to deliver the message to the nearby ambulance service andalso it is very much difficult for the ambulance to reach the scene of a crashand transport the victims to the hospital for treatment. The time between
injury and initial stabilization is indeed the single most important factor in
the victim’s survival for which immediate care is of critical importance.
Road traffic accidents do have an obvious spatial dimension that can beaddressed by Geographic Information System (GIS) which can help in rapid
information circulation, prompt emergency assistance and incidence
management, subsequently minimizing the road accident deaths. By
developing an on line tracking system based on GIS, the urban road safety
management system can be enhanced to provide immediate care to thevictims and handling the subsequent effects on the overall traffic system.
This paper focuses on the GIS based emergency rescuing system of road607

December 2007, Dhaka, Bangladesh

traffic accident victims. Detailed aspects of this system are discussed in thecontext of urban road safety and trauma management.

1. INTRODUCTION
In this era of automobile based personal transportation, road accidents havebecome of grave concern as a deaths, injuries and suffering. An effectivemeans of accident analysis and road safety management is needed to reduce
the number and severity of these accidents. People suffer from Road Traffic
Accidents (RTA) due to inadequate prompt casualty handling and absencesof Emergency Medical Services (EMS).Survival rates of medical
emergencies are dependent on rapid intervention by trained emergency
medical personnel. In most cases, the sooner trained emergency medical
rescue personnel arrive or vise versa, the greater chance for survival andconservation of life and property. Therefore, time is the critical factor andelement for the rescue of occupants and the application of emergency
service to minimize the losses when an emergency is reported. Indeed, thetime segment between incidence and the start of medical service has a direct
relationship to rescue of losses.
After an accident on crowded street of urban areas, it is difficult to
identify the nearby ambulance service center and to deliver the message andalso it is very much difficult for the ambulance to reach the scene of a crashand transport the victims to the hospital for treatment within a minimum
response time. In this paper an attempt has been made to develop a system
for Emergency Medical Service (EMS) using principles of GIS tools andtechnology to ensure prompt and quick response of Emergency Services(ES) for providing the best emergency medical treatment to the accident
victims within optimum response time after the incidence. The importanceof Emergency Medical Service and the current practices are also discussed.
At the very out set of this paper, the safety problem resulting from roadtraffic accidents with the particular emphasis on urban safety in developing
countries like Bangladesh are also highlighted.

2. THE GLOBAL ROAD SAFETY PROBLEM
Latest studies suggest that about 1.2 million people are being killedworldwide every year and up to 30-40 million people are injured or
permanently disabled due to road traffic accidents. Around 88 percent of
this road traffic deaths and injuries occur in the developing world andalmost half of those deaths and injuries take place in the countries of Asiaand the Pacific region. This worsening situation in developing countries isparticularly noted with a call to accelerate actions through multi-sectoralcollaboration, sharing information and knowledge with strong institutional
and political will. For every death, there are far greater numbers of injuriesfour persons with severe/permanent disabilities, ten persons requiring
hospital admission, and thirty persons requiring emergency room treatment(Jacobs, 2006 & Mackay, 2003). Although numerous strategies, programs

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and challenges have taken to control the road safety crisis all over the world
including developed and developing countries, yet the statistics still paint a
bleak picture of both current and predicted trends. The World HealthOrganization (WHO) predicts that by 2020 road accidents will be the third
most important cause of death or disability worldwide. Indeed, they are thesecond leading cause of death for people aged 5 to 25, with devastating
impact on families and communities. The majority of road casualties(injuries and fatalities) in developing countries are not motor vehicle
occupants, but pedestrians, motorcyclists, bicyclists and non motorized
vehicle occupants.
The economic costs of this epidemic are enormous, is estimated at up
to $100 billion, compared with total bilateral overseas aid amounting to$106.5 billion in 2005, ranging from 1 to 5 percent of GDP for every nation(IFRTD 2007). Indeed, road traffic injuries are an important obstacle todevelopment and place an enormous strain on a country’s health care system,and on the national economy in general (Ban Ki-Moon, 2007).
2.1

The Incidence of High Fatality Index

The road safety in low and middle income countries thus emerges
clearly a critical and major public health issue. Many Asian and Pacificcountries have an extremely high fatality index (i.e. deaths divided by total
casualties [including deaths] expressed as a percentage). The fatality index
depends crucially on accurate reporting of death and injuries but can also be
influenced by medical facilities (ADB, 1996). Unless prompt medical action
can be given to injured people with rapid and efficient emergency scheme,
their condition will deteriorate. However, it is clear that emergency medical
service and other intervention could do much to reduce the very high fatality
indices in the region.

3. ROAD SAFETY PROBLEMS IN BANGLADESH
There is no doubt that road transportation is vitally important to our
economic and social welfare and must be so maintained and continually
improved with due consideration of safety, minimizing accident hazards andrisks. Each year as reported to police, more than 3000 individuals- includingfrom among our peers, our family, our friends and our coworkers- lose theirlives in road traffic accidents in Bangladesh and many more sustain
disabling injuries. It is estimated that the actual fatalities could well be
10000-12000 each year taking consideration of underreporting anddefinitional inconsistencies (Hoque, 2005).

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Bangladesh
10000
200000500000
1 million
For every injury death, 50 injured attend emergency care
500,000 people are estimated to visit emergency room

Figure 1: Pyramid of road accident casualties in Bangladesh(Rhaman, 2007)
In economic terms, road accidents in Bangladesh costing community
in the order of Tk. 5000 crore (US $ 850 million) which is nearly 2 percent
of GDP. This is, of course, a huge some that the nation can ill afford to loss
(Hoque, 2006).

4. ROAD SAFETY ISSUES IN URBAN AREAS OF BANGLADESH
Rapid urbanization in developing countries presents tremendous challenges
to the transport systems of expanding cities if they are to meet the accessand mobility needs of their communities and provide them with asustainable, safe and healthy environment. To meet this expansion, many
developing world cities are increasing the capacity of their road networks,
but often at the expense of the safety of the vulnerable road users. As aresult many people die and are injured unnecessarily in road crashes. The
situation is critical particularly in metropolitan Dhaka, one of the mega
cities of the world today. Statistics reveal that, about 23 percent of country’sroad accidents occurred in the Dhaka Metropolitan area. The most
predominant accident types are hit pedestrians, rear end collisions, sideswipes and head on accidents which accounted for around 86 percent of
metropolitan accident profile. Accident data also showed that out of the total
fatalities, by far the largest proportion constitute the vulnerable road users
mostly pedestrians. Pedestrians account for 72 percent of all fatalities in the
Dhaka Metropolitan area. The share of pedestrian facilities is also very highin median size city of Bangladesh viz. Mymensingh 73 percent, Sylhet 63
percent and Bogra 43 percent (Hoque, 1996).

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Figure 2: Hospital burden by RTA victim
Typically the principle contributing factors of pedestrian fatalities aswell as overall fatalities after accidents in urban areas are improper
knowledge of first aid and other life savings skill, miss handling of victims,
absence of prompt emergency assistance, inadequate emergency medical
and trauma centre, inefficient trauma care management system, lack of rapid
response of service center, transportation and communication problem, lackof co-ordination between medical centre and victim manipulators, absenceof proper and organized Emergency Medical Services (EMS) etc.

5. THE CONTEXT OF EMERGENCY MEDICAL SERVICE (EMS)
5.1

Importance of Emergency Rescue to Accident Victims

Since 200 years ago, when "flying ambulances" or light horse-drawn
carriages were introduced to carry the wounded from the battlefield in
Europe, there has been a slow but steady increase in the sophistication of
emergency medical services, often accelerated by the requirements ofwartime situations. Mortality rates dropped from 4.5 deaths per 100
casualties in World War II to less than one in recent times. This reduction
was due, at least in part, to a reduction from hours to minutes in the timerequired to reach medical care and to the provision of effective care "at thescene" by trained paramedical personnel (ADB, 1996).
About 50 percent of road traffic deaths happen within 15 minutes of
the accident as a result of injuries to the brain, heart, and large blood vessels.
A further 35 percent die in the next 1-2 hours of head and chest injuries, and15 percent over the next 30 days from sepsis and organ failure. So, the time
between injury and initial stabilization is the single most important factor inpatient survival, with the first 30-60 minutes being the most important(ADB, 1996).
The most serious injuries resulting from traffic accidents are head,spinal, and internal soft tissue damage to vital organs. Early treatment andstabilization of these typical accident injuries can enhance a patient's timely
and full recovery. Delay or well-intentioned but inappropriate first aid, canresult in death or permanent disability. Medical experience around the world
has demonstrated that stabilization of the injured person and hospitalization

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to a specialist center, within what they describe as the "golden hour,"increases the patient's potential for survival and full recovery.
5.2. Generalized Emergency Medical Service System (EMS)
There are two general philosophies in the "formal" provision of
emergency medical care. One of these formal approaches is to provide
immediate first aid and emergency care at the scene of the incident, then totransport the injured person to the emergency department as fast as possible.
It is there to skilled and definitive care, the so-called scoop and run
philosophy. This approach is taken in countries such as Australia, New
Zealand, United Kingdom (UK), and parts of the US (ADB, 1996).
The alternative is to carry the skilled care to the site of the incident
and there provide appropriate treatment. This approach is taken in France,
Germany, and Russia, where well equipped vehicles carry skilled doctors to
the scene.
A third approach, an "informal system," is found in many situations incountries in the Asian and Pacific region. Since there or passing motorists
and carried to the nearest emergency department by whatever transport isavailable, usually without any treatment or first aid at the scene. This resultsin rapid transport to the emergency department but without any resuscitation
measures. The outcome of this system depends to some extent on thecapacity of the emergency department to deal with these severe cases and toprovide effective treatment on arrival (ADB, 1996).
Although there is a great diversity in application and practices, there is
general agreement on the principles of an effective emergency medical
service. The essential functions of such a service are as follows (ADB,
1996):• the provision of first aid and medical care to the casualties at theroadside;• the transport of the casualties to a hospital; and• the subsequent provision of more definitive treatment.
The typical components of an ambulance service in a developed
country are as follows:• a notification and communication system;• central control and coordination of operations;• effective rescue and medical aid at the scene; and• transport to a hospital and the provision of definitive care in an
emergency department.
In the light of the above principles, it is important to develop an
emergency rescue system to ensure that the accident victims get the best
emergency medical treatment practically possible in cognizance of the local
situations.

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5.3. The Situation in Bangladesh
As indicated earlier, the fatality rates viz. the estimated number ofroad traffic accident fatalities per 10,000 registered vehicle of Bangladesh(over 100) is very high by international standards, as the fatality rates formotorized countries is usually less than 2. The fatality index in Bangladesh
is nearly 40 percent, which is the highest among the developing countries.
This signifies probably two important characteristics, viz. the wide spread
under reporting of less serious accidents and the lower level of emergency
medical services available to accident victims. In Bangladesh with thepresent level of medical services, there is little scope to provide the prompt
and necessary medical attention to injured people, particularly soon after an
accident (Hoque, 2003).
Salahuddin and Khandaker (2006) in their study on emergency
medical services for road traffic accidents in Bangladesh briefly reviewed
the present emergency medical service system in Bangladesh. They pointout that, in general public handle improperly the RTA victims without
proper knowledge of first aid, Cardio Pulmonary Resuscitation (CPR) andother life saving skills. To avoid the harassment of police cases people
usually avoid their involvement in helping someone in RTAs. Though somehumanitarian people willingly handle such casualty but they don’t know
how to do that properly. Usually the rickshaws or auto-rickshaws carry themto the nearest public healthcare providers- more often those are the medicalcolleges. Nearest hospitals and clinics simply deny giving emergency
medical aid that can save many lives. On the way to the hospital 90%
casualties come to a fatality because of excessive bleeding. The scenario in
first medical response and casualty management in RTA is similar in allover the country.

6. THE POTENTIAL OF GEOGRAPHIC INFORMATION SYSTEM
A brief outline on application and potential of Geographic Information
System (GIS) in the field of data analysis, location identification, graphicalrepresentation and network analysis are presented by Affum and Taylor(1996), ESRI (2007). They pointed out that in this modern era, GIS is one ofthe proven and widely used tools for complex incident analysis to display
trends, illustrate patterns and identify areas of incidence all over the world.
Organizing information so it can be accessed by pointing to a region or a
specific location on a map is used in a variety of applications. Systems that
support this task are called Geographic Information Systems (GIS). The
information available is data that relates to specific locations. GIS canintegrate graphic information and data in databases to support the
production of geographic information for further arrangement, analysis, andmanagement and maps which are produced and displayed by GIS present
excellent visual interpretations of data which are hardly can be achieved bylanguage and letters.

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7. APPLICATION OF GIS IN EMS
In the emergency rescue of accident victims, initial response time is a very
important factor in determining the quality of pre-hospital EMS. The GIS
can assist in emergency rescue operations by identifying where help isneeded and helping to direct resources in an efficient manner to reduce theresponse time by the development and implementation of an emergency
medical services (EMS) response system. GIS can quickly analyze anddisplay a route from a station or GPS location to the emergency call. Thisroute (depending on the sophistication of the street file) may be the shortest
path (distance) or the quickest path (depending on time of day and traffic
patterns). In network analysis, the “optimum path" is derived by considering
many criteria. In EMS system, to locate the shortage path, these criteria
could be the level of the road, one way or two way transportation, speed
limit, congestion period, number of intersections etc. Indeed, emergencies
are very dynamic and, as circumstances change, GIS can reflect thesechanges also.
GIS technology is being deployed in a number of other emergency
response areas to increase efficiency and reduce time and provide higherquality decision support information and data. This includes dispatch,
mobile operations, and emergency management. The proposed use of GIS
with EMCS will alleviate the damage to life or save life by suggesting firstaid location and by admitting the patient to the nearest suitable hospital.

8. A PROPOSED EMS SYSTEM FOR URBAN SAFETY
In the light of the preceding discussions and in the absence of rapid andefficient system of emergency rescuing of accident victims, a frameworkof effective rescue system using GIS tools for facilitating emergency
medical service of accident victims is proposed. The detailed methodology
and steps of the system are described in the form of a flow chart in Figure 3.
This framework/flowchart essentially provides series of actions andinformation exchange following the reporting of an accident involving
serious causalities for ensuring their proper and timely emergency care. This
framework can be applied for any events of public emergency service.

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Incident

PublicEasy Access

Nearest ESC

ESC

Reach to the Spot withrequired materials

Contact with Control
CentreCentral Control andCoordination Centre

Data analysis

Information Disposal andCo-ordination

Actions

Duty Officer

GIS data base

Shortage RouteVictims/
Duty Officer

Reach to theConvenient ESC

Figure 3: Flow chart of system
8.1

Brief Description of the System Components• Events/Incidents: This refers to any type of event which creates

public disturbance, sufferings like road accident, fire, and crime or
any other natural hazards and pandemic etc. It may occur anywhere,
at any location, at any time, and in various different ways - thus
making any one of us susceptible.
• Contact and Information Exchange: Of most importance in thesystem is the immediate contact and information circulation
regarding the incidence and victims. This information involves
location, incident type, details of injuries and any special medical
treatment needed etc. This information will be exchanged by the
local viewers of the incidents or local police or duty traffic police
to the control center.
• An Effective Notification and Communication Network: There

should be a single convenient method of notifying the control room
about the location and nature of the incidence. In many countries
this is a telephone number such as 999, 000, or 111, which operates

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December 2007, Dhaka, Bangladesh

throughout the country and provides telephone access to all
emergency services, police, fire, and ambulance. Ideally, these callsshould also be without charge. An additional requirement for this towork is that there must be a way of identifying the exact location of
the incident.
The central control center will receive calls from the public and/or
duty officers about the incident and dispatch the information to the nearest
and competent Emergency Service Center (ESC) (hospital, fire service,police station etc.) and/or to the duty officer to take immediate actions withgiving details of injuries and any special medical treatment needed. The
control centre will also follow-up and co-ordinate with the ESC to ensure
the effective and reliable rescue and emergency incidence management like
medical aid after the incidence.
• Comprehensive GIS data base system: There should have acomprehensive and details GIS base database of road network, with
the information of road name, type, width, traffic characteristics,
node id, link id, length of link etc. and location of utility services
with the information of name, facilities, location, contact number,land marks etc. The data base information may also includes thelocation of critical facilities, including hospitals, nursing homes,
schools, parks, shopping areas, business areas, manufacturing areas,
and transportation routes.
• Analysis: After receiving the information, data analyst will locate

the incidence location and the required ESC will be identify withina particular radius from the incidence location. Then, the nearest,
capable and potential centre is marked out and subsequently finds
out the shortage and reliable distance using GIS database by
Network Analysis.

Figure 4: Accident spot and all hospitals within 1 Km radius

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Figure 5: Network analysis to find the nearest and capable hospital.
Figure 4 & 5 is an example of analysis. Figure 4 generated by GIS
illustrating the location of the spot and location of hospital within one
kilometer radius. This map also shows that there are nine hospitals withinthat circle which are denoted as chronological number 1 to 9. Figure 5
represent two probable shortage routes to reach the spot from two nearest
hospitals with priority 1 and 2 in different color green and red respectively.
• Information disposal: Dispatchers have an important responsibility

to process emergency calls and send the appropriate public safety
resources to the emergency location based on the type and urgencyof the incident. According to the data analysis, the information will
dispatch to the service centre for immediate action informing about
the location, shortage path, nature and severity of injuries or to the
local duty officer informing the nearest medical service centre.
• Actions: Service centre or victims/duty officer will take immediate

action to reach the emergency service team to the spot withrequired materials or victims will send to the convenient nearest
ESC.

9. CONCLUSIONSIn any emergency disastrous situation it is crucial that the right tools areavailable for operational personnel (viz. fire brigades, emergency service,police or armed forces) at all levels for them to make right decisions forappropriate actions as quickly as possible. GIS is one of such potential tools
which have the capability in organizing the extensive amount of spatial data
both generated and utilized during an emergency. A properly designed andimplemented GIS will allow managers and responders to access critical

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location data in a timely manner so that lives and properties can be protected
and restored.
The deaths and injuries resulting from road traffic accidents have now
emerged as a serious safety problem particularly in urban areas of
Bangladesh. In order to minimize the extent of deaths and injuries and theirresulting adverse social and economic consequences an effective trauma
management system needs to be developed and operated to provide
supportive care to the casualties at various stages viz. at the accident scene,
pre-hospital and hospital treatment. In this paper a GIS based system of
emergency rescuing of accident victims has been described. This system isconsidered as a vital element to the overall trauma management process andprovides opportunity in rendering timely emergency medical services byrapid information circulation and thereby ensures minimum time response
for prompt assistance and incidence management. While this system would
help minimizing road accident deaths, disabilities and sufferings, it will also
alleviate associated traffic congestion and operational hazards. Apart fromrescuing road traffic accident victims, the system can be introduced forother emergency and disaster management process in urban areas.
Further research and studies in this regard are underway at the
Accident Research Centre (ARC) at BUET to address the requirements viz.
equipment/vehicles, software, ITS, management and coordination, enriched
and updated database, training of personnel and funding for its fulldevelopment and subsequent implementation.

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Hoque, M. M. (2006), ‘Road Safety in Bangladesh: The
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Dhaka, Bangladesh.

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model of EMS: reducing ambulance response time”, Trauma andEmergency Medicine Research Unit, The Gertner Institute for Health Policy
Research, Sheba Medical Center, Tel-Hashomer, Israel.
Rahman F., ‘Community road safety In Bangladesh: a priority social
responsibility’, Road Safety Workshop, setting road safety priorities in
Rajshahi region, 2006

Urban Road Safety: Effective Rescue of Accident Victims Using GIS Technology

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December 2007, Dhaka, Bangladesh

620

New Technologies for Urban Safety of Mega Cities in Asia

COMPARATIVE ANALYSIS OF
ON-STREET PARKING MANAGEMENT
PRACTICES IN DIFFERENT COUNTRIESSHINJI TANAKA, MASAO KUWAHARAThe University of Tokyo, Japan
stanaka@iis.u-tokyo.ac.jp
ABSTRACT
Illegal on-street parking is one of the major causes of traffic
congestions and sometimes traffic accidents in urban streets. Therefore, anappropriate management of on-street parking is very important. In thisstudy, a questionnaire survey was conducted to understand parking
management strategies from the practice in 11 different countries. The
questions are about institutions in charge of parking management, parking
regulations, fees and fines, enforcements, ITS technologies, parking
management policies and so on.
In view of the result, one possible parking management strategy forJapanese cities is proposed, that is, modulated parking regulation,utilization of curbside space and so on. The validity of this proposed
parking space is evaluated through a simple analysis using traffic
simulation.

1. INTRODUCTION
Illegal on-street parking is one of the major causes of traffic congestion in
urban area because it reduces the traffic capacity of urban streetssignificantly. And sometimes, it may cause traffic accidents as an obstacle
on a road. From the viewpoint of smoothness and safety, all parking
vehicles should be removed from streets and parked in off-street parking
garages. However, there are some vehicles, especially commercial ones,
which have to repeat short stop for loading / unloading goods in manydifferent locations. If they are forced to park off-street, the efficiency of
their business would be largely deteriorated. And urban businesses andactivities are supported by these vehicles. Therefore, it may be difficult to
employ no parking regulation simply. We need to find more acceptable andrealistic solution.
In Japan, on-street parking is prohibited in the most part of urban area
in principle, because road is recognized as running space, not for parking.
However as there exist vehicles that need to park on-street as mentioned
above, there are a lot of illegal parking vehicles on streets in reality due tothe shortage of enforcement ability. This gap between the principle and thereality may cause sense of unfairness among road users, and might lead to akind of moral hazard. It would be meaningful to reconsider the current

621

December 2007, Dhaka, Bangladesh

system to realize an orderly traffic situation. For this purpose, to survey
parking management practices in different countries would be a good way toinvestigate possible parking management alternatives.
In this study, a questionnaire survey on parking management practices
was carried out in 11 countries. Based on the result of a comparative
analysis, one possible parking management scheme for Japanese cities is
proposed. And the validity of this scheme is evaluated through a simple
analysis of traffic simulation.

2. QUESTIONNAIRE SURVEY
2.1

Outline of the survey

A questionnaire survey was designed to understand parking
management practices in different countries. The countries and cities
answered are shown in Table 1. The questionnaire survey was answered bytransportation researchers and engineers in these countries.
Table 1: Surveyed countries and cities
Country
City
Population (ths)
The United States
San Francisco
798
The United Kingdom
Leeds
715
FranceParis
2,150
Germany
Darmstadt
138
The Netherlands
Delft
95
Italy
Turin
902
Switzerland
Geneva180
IsraelHaifa
300
South Korea
Yeosu
320
Thailand
Bangkok
6,355
Japan
Tokyo
8,520
The questions are about institutions in charge of parking management,laws and ordinances, systems, regulations, charging, enforcement, fine,parking policy, related ITS technologies and so on.
2.2

ResultRepresentative results are shown in the following sections. Note thatin some countries transportation system and regulation is different by cities,
therefore the result shown here is not always applicable throughout thatcountry.
2.2.1 Definition of parking
In some countries, “parking” is distinguished from “stopping” or“standing”. For example, it is defined by time duration in Germany and622

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

Switzerland, and by the fact that the driver leaves the vehicle in the UnitedStates and France.
Table 2: Definition of parking
StatusCountries
Time duration larger than a certain length
Germany (3 min),
Switzerland (15 min)Driver’s absence from the vehicle
The United States, France
Both above
Italy, Japan
2.2.2 Charging measures
Parking meter and pay & display system are the most widely used inmany countries. Coupon ticket and manual collection are also seen. As for
new technologies, smart card in common with public transportation andmobile phone charging are introduced in some countries. In-vehicle meter
which indicates arrival time on the dashboard is used in Germany and
Switzerland although it is not a charging measure.
Table 3: Charging measures

○

Japan

○
○
○

Thailand○○○○South Korea

○
○
○

○
○
○

Israel○○○○Switzerland

○

Italy

○

Netherlands

Germany

UK○○

FranceUS
Meter○
Pay & display○
Coupon ticket
Smart card
Mobile phone
Manual collection
In-vehicle meter

○
○

○
○

○

○

2.2.3 Operation of parking meters
As a typical charging measure, way of operating parking meters is
asked. Minimum charging unit time is usually 30min or 1 hr, however, 15 /30 / 60 / 120 min of unit time and sometimes 5 min for loading / unloading
vehicles are defined in the United States. This kind of fine unit time seems
effective to reduce unnecessary on-street parking and to enhance efficientuse of on-street parking spaces.

Comparative Analysis of On-Street Parking Management Practices in Different Countries

623

December 2007, Dhaka, BangladeshCountry

US
UK
FranceGermany
Netherlands
Italy
Switzerland
IsraelSouth Korea
ThailandJapan

Table 4: Operation of parking meters
Unit time
Maximum time Operation
limit variationhours
15, 30, 60, Day, Time ,120 min
Location
2, 4 hr
Constant
N/A
30 min - 2 hr Location
2 hr
Day, Location
30 minDay
2 hr
Day, Time,
Location
N/A
N/A
15 minConstant
60 minConstant

Parkingout ofoperation hours8-18h

OK

8-18:30
8-20h
8-20h
8-20h
8-12:30,
13:30-19
7-17h
8-21h
9-17h
8-20h

NG
OK
OK
OK
OK
OK
OK
OK
OK
NG

2.2.4 Charging rate of parking meters
In most countries, charging rate of on-street parking is cheaper thanoff-street parking except for the United States, where it become possible toinduce less necessary vehicles to off-street parking garages. To bring out
this effect, charging rate should be different depending on location and timein one city although it is constant in some countries. Some countries employ
progressive charging which charges a higher rate for a longer parking and it
also has an effect to induce long-term parking to off-street parking garages.
Table 5: Charging rate of parking meters
Country
Off-street
On-street
Rate(per hr)(per hr)variationUS
2-3 USD
4 USD Day, Time,
LocationUK
1.5-3 GBP
1.5-3 GBP Day, Time,
LocationFrance2-3 EUR
1-3 EUR Day, Time,
Location
Germany
1.5 EUR
1 EUR Location
Netherlands
4 EUR
2-4 EUR Constant
Italy
1 EUR
1 EUR Location
Switzerland
2.5 CHF
2.5 CHF Day, Time,
Location
Israel4 USD
1.2 USD ConstantSouth Korea
1000 KRW 1000 KRW Location
Thailand50 THB
10 THB ConstantJapan
600 JPY
300 JPY Constant624

Progressi
ve rate
No
Yes
Yes
No
Yes
No
No
No
No
No
No

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2.2.5 Institutions of enforcement
In most countries, municipalities and contracted private sectors
operate enforcement of illegal parking in addition to the police. In the
United States and the Netherlands, specialized parking section is sometimes
prepared in a municipal organization. As for the role of municipality /private sector and police, the former issues tickets for normal illegal parking
and the latter enforces more serious parking violation, usually.
Table 6: Institutions of enforcement

○
○
○

Japan

○
○

Thailand○South Korea○○○

Israel○○Switzerland

○

Italy

○
○

Netherlands○○

Germany

UK○○○

FranceUS

PoliceMunicipality
Private sector○○○

2.2.6 Fine
As for the fine of parking violation, Japanese one is the highest as awhole. However, some countries charge much higher fines in case theviolation is serious, e.g. violation in priority space for handicapped people,
fire hydrant and dangerous spot which obstruct other traffic. It shows an
idea that the amount of fine should be varied depending on the influence.

Country
US
UK
FranceGermany
Netherlands
Italy
Switzerland
IsraelSouth Korea
ThailandJapan

Table 7: Amount of fineFine
40-60USD, priority space and fire hydrant: 200USD
50 GBP
unpaid: 11EUR, obstruction: 35EUR, priority space:
135EUR
unpaid: 5EUR, obstruction: 40EUR
54 EURoverstay: 40-100CHF, unpaid: 40-120CHF
18 USD
40,000 KRW
500 THB
10,000 - 18,000 JPY

2.2.7 Owner’s responsibility
All the countries surveyed this time already introduced owner’s
responsibility of illegal parking vehicle, which means, if the driver of theillegal parking vehicle is not identified, the owner of the vehicle owes the
responsibility to pay the fine. And here, one group (the United States, theComparative Analysis of On-Street Parking Management Practices in Different Countries

625

December 2007, Dhaka, Bangladesh

Netherlands, South Korea) firstly charges the responsibility to the driver andsecondly to the owner if not identified. The other group (the United
Kingdom, Germany and Italy) charges to the owner from the first and does
not inquire who pay the fine eventually.
2.2.8 Decriminalization
Parking violation is decriminalized together with other traffic
violations in many countries, that is, it is treated not as “crime” but as“offense”. This makes possible for municipalities to enforce parking
violations.
2.2.9 Role of on-street parking
As for the role of on-street parking in traffic management policy, one
group (Italy, Israel, South Korea and Japan) has a principle that parking
should be done off-street, whereas the other group (the United States,
France, Germany, the Netherlands, Switzerland and Thailand) allows onstreet parking depending on necessity. The latter case can be understood thaton-street parking is established as an important mode of parking.

3. PROPOSAL OF ON-STREETSCHEME FOR JAPANESE CITIESPARKINGMANAGEMENT

Focusing on Japanese on-street parking management scheme, issues of thecurrent system is pointed out based on the result in the previous chapter.
Then a new scheme of on-street parking management is proposed.
3.1

Issues in the current system

From the comparative analysis in the chapter 2, it is revealed that
there are some issues to be improved in the current Japanese parking
management system. The principal ones are as follows.
• On-street parking is regarded as a tentative mode of parking until
off-street parking garages are constructed sufficiently.
• A common understanding of priority vehicles which should park
on-street is not established.
• Parking regulation is not differentiated depending on location andtime.
• Charging rate is constant throughout one city, not time-progressive,and less expensive compared with off-street parking garages nearby.
• Unit time of parking meters is apart from the duration of actual
parking behavior.
• Enforcement of parking violation is not strict very much and thefine is not differentiated by the influence.

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3.2

New scheme of on-street parking management

Considering these issues, new scheme of on-street parking
management should satisfy the following points.
(1) Modulated regulation
The level of parking regulation should be modulated, that is, illegal
parking at very influential spots should be strictly prohibited whereas
parking at less influential spots can be allowed. Same things can be said intime, duration, vehicle type and fine. This kind of modulated regulation
prevents drivers from parking at seriously influential and dangerous spots.
(2) Creation of on-street parking space
Next, it is necessary to create on-street parking space considering onstreet parking demand. Here, it is not enough to ensure the amount only. We
have to make sure the space is appropriately distributed, e.g. small space ineach block, because on-street parking is used for short stop and the distanceto the building become critical.
(3) Appropriate enforcement
To ensure the effectiveness of the parking management scheme, astrict enforcement of parking violation is essential. An appropriate
enforcement helps to realize an orderly traffic situation.
The important thing is to consider not only parking vehicles but also
the relationship with running vehicles. In other words, this is a matter ofassignment of limited road resources between traffic function and accessfunction depending on the local situation.
3.3

Design of on-street parking space

Then next issue is how to design on-street parking spaces in existing
urban streets. As for traffic congestion in an urban area, the bottleneck isalways at a signalized intersection, because the limited amount of green
time has to be allocated among different directions of traffic. Therefore, onstreet parking around an intersection which reduces the road capacity
significantly should be strictly controlled. In other words, there is someroom to allow on-street parking at a straight section between intersections.
According to this idea, the authors propose to create on-street parking
space between intersections as shown in Figure 1, that is, to make an onstreet parking bay at a straight pipe section between two intersections and tokeep the maximum capacity at the intersection.

Comparative Analysis of On-Street Parking Management Practices in Different Countries

627

December 2007, Dhaka, Bangladesh
On-street parking spaceat straight pipe section

Ensure maximum capacity
at intersections

Figure 1: Proposed design of on-street parking space

4.

TRAFFIC SIMULATION ANALYSISThe proposed on-street parking space is designed inside road space, so theroad width for passing vehicles has to be narrowed. Therefore, it should be
carefully designed not to reduce the capacity at the intersection. If designed
appropriately, the congestion level of the network remains the same. To
confirm it, a simple simulation analysis was done as follows.
4.1

Setting

The principal design elements of the proposed on-street parking space
are the distance from adjacent signalized intersections (named “clearance
distance”) and their cycle length. For the simulation, 2 and 3 lanes street
with signals on both ends were prepared as shown in Figure 2. We ran
several settings of the simulations changing some variables shown in Table
8.
detector

demand800 / 1200
veh/h/lane

2 / 3 lanes
lane width 3m
L
50 / 100 m

L
50 / 100 m

cycle length
60 / 120 sec

distance between intersections 300 m

Figure 2: Representation of on-street parking space in the simulation
Table 8: Setting of the simulation
Item
Setting
number of lanes
2, 3 [lanes]
distance between intersections
300 [m]distance from intersection to parking space 50, 100 [m](clearance distance) (L)cycle time (C)60, 120 [sec]green time
60% of the cycle timeoffsetsimultaneous offset
traffic demand (Q)800, 1200 [veh/h/lane]

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New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

4.2

ResultFirst, let us see the result of 2 lanes simulation with the demand (Q) of
800 [veh/h/lane]. When the cycle time (C) is 120 [sec] and there is no
parking space, the throughput of this section is 1447.6 [veh/h]. Here, if
parking space is located with clearance distance (L) as 50 [m], thecumulative curve of the passing time of vehicles is shown in Figure 8.
veh
180

upstream intersection

160

parking section

140

downstream intersection

120
100
80
60
40
250

350

450

550

sec

650

Figure 3: Cumulative curve (L = 50 [m], C = 120 [sec])
Next, if the clearance distance is set up as 100 [m] and the cycle timeis set up as 60 [sec], the cumulative curve becomes as in Figure 4.
veh
270
250
230

upstream intersection
parking section
downstream intersection

210
190
170
150
130
400

500

600

700

sec

800

Figure 4: Cumulative curve (L = 100 [m], C = 60 [sec])
Comparing these two, the latter has a larger gradient, which means it
has more ability to process traffic demand. (Note the displayed range ofthese two graphs is the same.) Actually, the throughput of the latter is1425.2 [veh/], which is much larger than that of the former 1102.2 [veh/h]and almost the same as the situation of no parking space (1447.6 [veh/h]).
In the same way, different cases are simulated with the combination of
the parameters mentioned above. The results are shown in Table 9 and 10.
Of course, no parking space situations have the largest value of thethroughput. When the parking space is located with L = 50 [m], the value ofthe throughput is reduced. However, as the cycle time is shortened and theclearance distance is extended, the value of the throughput is improved.
Assuming the no parking situation 100%, the throughput rate is improved
from 59.5% (L = 50 [m], C = 120 [sec]) to 77.1% (L = 100 [m], C = 60
[sec]) in the case of 2 lanes, and from 71.5% (L = 50 [m], C = 120 [sec]) toComparative Analysis of On-Street Parking Management Practices in Different Countries

629

December 2007, Dhaka, Bangladesh

88.6% (L = 100 [m], C = 60 [sec]) in the case of 3 lanes. From these results,
it seems to be possible to keep the enough high throughputs setting
appropriate clearance distance and cycle time.
Table 9: Throughput of 2 lanes road [veh/h]
Case
Q=800 [veh/h]
Q=1200 [veh/h]no parking space (C=120 sec)
1447.6
1856.9L = 50 m,
C = 120sec
1102.01105.9C = 60 sec
1253.31238.1
L = 100 m
1247.41285.4
L = 100 m, C = 60 sec
1425.21431.0
Table 10: Throughput of 3 lanes road [veh/h]
Case
Q=800 [veh/h]
Q=1200 [veh/h]no parking space (C=120 sec)
2240.92758.6
L = 50 m,
C = 120sec
1930.01973.2C = 60 sec
2156.92180.5
L = 100 m
2045.22055.4
L = 100 m, C = 60 sec
2093.62445.1

5.

CONCLUSIONSIn this study, on-street parking management practices were surveyed andcompared through questionnaire survey among 11 countries to find betteron-street parking management schemes. From the result, a couple of issues
in the current Japanese system were indicated, and one possible
management scheme was proposed. The key of the proposal is to make amodulated parking regulation and to create on-street parking space between
intersections inside existing streets. Then the feasibility of the proposed
parking space was evaluated by a simple analysis of traffic simulation andthe result showed a possibility to create on-street parking space without
deteriorating traffic smoothness.
All vehicles have to be parked eventually after they are used.
Therefore, parking management is one of the most important issues intraffic management policies. And, an appropriate parking management
strategy is different depending on the traffic situation in each country. For
the next step, we’d like to consider appropriate parking management
strategies applicable to Asian mega cities.

REFERENCES
Allison L. C. de Cerreño, 2002. The Dynamics of On-StreetParking in Large
Central Cities, Rudin Center for Transportation Policy &Management, NYU Robert F. Wagner Graduate School of PublicService630

New Technologies for Urban Safety of Mega Cities in Asia

PUBLIC TRANSPORT IN BANGKOK:A CASE OF THE PASSENGER VANS
SHINYA HANAOKA
Department of International Development Engineering
Tokyo Institute of Technology, JAPANhanaoka@ide.titech.ac.jp
SUPAPORN KAEWKO LEOPAIROJNA
Department of Urban and Environmental Planning
Kasetsart University, THAILAND
supaporn_k@hotmail.com
ABSTRACTThe passenger van services in Bangkok were initiated as informal
public transport. Passengers preferred these services to conventional buses
due to their speed, comfort and ease of access at affordable fares. The
popularity caused public bus operators to judge passenger vans ascompetitors who affected reduction of their passengers and revenues.
Consequently, the government started enforcing passenger van regulationsin 1999. According to the regulations entry of the passenger vans andmaximum fares are controlled. In this paper, the authors studied
background of the passenger van services, and analyzed the passenger vanmarket using data from the supply side, i.e., the passenger van drivers andthe demand side, i.e., the passengers on the passenger vans and theircompetitive modes. Market analysis under the existing regulations showedthat there was no price competition at the route and corridor levels. On theroute level, the passenger van market was an oligopoly market with
implication of collusion. At the corridor level, the market was an oligopoly
market with implication of product differentiation.

1. INTRODUCTION
The passenger van services supply 12-seat air-conditioning vans withguaranteed seats. It provides fast and comfortable road-based public
transport mode for middle-income passengers who travel between suburbs
and city centres. In 2003, passenger vans and bus carried about 3% and 26%,
respectively, of daily person trips in Bangkok and the neighbouringprovinces (OTP, 2004). The service was initiated illegally as it operated
without proper government licenses. Nonetheless, passengers preferred thismode to conventional buses because of its speed, comfort and ease of access
at affordable fares. Even though modal share of passenger van was not sohigh, public bus operators considered passenger vans as competitors andclaimed that the competition caused reduction of their passengers andrevenues. Consequently, the government started enforcing passenger van
regulations to ease competition and to provide legal services to thepassengers in 1999 (DLT, 2003). Though the regulations, safety and631

December 2007, Dhaka, Bangladesh

qualities of the passenger van services are assured and the entry of numberof the passenger vans and maximum fares are controlled.
In this paper, the authors studied background of the passenger van
services, and analyzed the passenger van market using data from the supply
side, i.e., the passenger van drivers and the demand side, i.e., the passengers
on the passenger vans and their competitive modes.

Photo 1: Passenger vans in Bangkok

2. BACKGROUND OF THE PASSENGER VAN SERVICES
2.1

Development of the passenger van services

Passenger van services were started by groups of investors. Since theLand Transport Act B.E. 2522 (1979) states that operating public transport
services requires official permission from Department of Land Transport(DLT), the passenger van services were then considered illegal for thereason that they operated without DLT permission. Additionally, the Motor
Vehicle Act of B.E. 2522 (1979) prevents drivers from operating the vans as
public vehicles when the vans were registered as private vehicles.
Furthermore, according to the Royal Decree Establishing Bangkok Mass
Transit Authority (BMTA) B.E. 2519 (1976) only BMTA is authorized toprovide bus services and other bus operators require BMTA sub-contracts.
Despite existing government policy to eliminate the passenger vansthe services kept on expanding in 1990s as suburbs of Bangkok developed
to be residential areas and most working places continued to be located incentral areas. The passenger vans are preferred by the middle-income
passengers because, 1) they charge similar fares to the conventional airconditioning (a-c) buses but offer more comfort in the form of guaranteedseats, 2) they reduce travel times since their smaller vehicle size enables
them to move quickly through congested roads, they have fewer stops, andsome of them operate on expressways, and 3) they offer a level of service
similar to taxis but lower fares and they give a better sense of safety forfemale passengers (Leopairojna and Hanaoka, 2005).
The popularity of the passenger vans caused BMTA and its jointservice operators to consider the passenger vans as competitors who
affected reduction of their passengers and revenues by interloping the bus
routes and “cream skimming”- operating on high demand routes.
Furthermore, relationships between the investors and the influential figures

632

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

in the passenger van industry led to bribery issues. Therefore, in 1999 thegovernment implemented the policy of “Passenger Van Order” and enforced
passenger van regulations to eliminate competitions between the passengervans and BMTA bus services, ensure good public transport services, and to
reduce problems of the influential figures and corruption (DLT, 2003).
Government determined number of passenger vans based on the politicalinfluence without considering market structure. Market structure of thepassenger vans should be studied.
2.2

Regulations regarding the passenger van services

DLT and BMTA are the two main agencies to enforce the passenger
van regulations. The regulations under DLT licenses and BMTA contracts
are shown in Table 1. As the regulator, DLT provides seven-year license tooperate the passenger van services to BMTA, monitors the passenger van
services and withdraws license of routes that are below DLT standards. As
authorized operator, BMTA distributes its two-year sub-contract rights tooperate the passenger van services to the drivers, supervises and discards
contracts of the driver, who do not follow BMTA regulations or fail toafford the concession fee, and transfers the contracts to the new driver.
Table 1: Regulation regarding the passenger van services
In the DLT Transport Business Licenses, the following conditions are fixed:- Route alignment (total 116 routes), origin and destination- A minimum and maximum range of passenger vans (passenger van quota - total
3,964-5,574 vans)- Type and colour of a passenger van (following DLT standards) and capacity (notmore than 12 seats)- Daily work time (head office and local office must be open from 8.30am to 4.30pm
on business day)- Operating hours (6.00am to 10.00pm) and minimum total daily trips (detailed
timetable and headway are set by a terminal manager of each route)- Maximum Fare (such as, passenger vans on route 1 can charge not more than 15
baht/person/trip)
Note: Fares are fixed at not more than 1 baht/km for the first 10 km and not morethan 0.60 baht/km for each additional km. An additional fare, not more than 5baht/person/trip, is allowed for routes operated on expressways and toll way.
In the BMTA contracts, the passenger van drivers have to respect the BMTA
regulations as follows:- Picking up passengers only at origins and drop off them at bus stops along routes
or at destinations, asking passengers to get off before arriving at their destinations
is prohibited- To operate vans outside regular routes, drivers have to get official permission from
DLT and BMTA
- To stop temporarily for repairing or for some reasons, drivers have to inform
BMTA- Monthly concession fee (1,070 baht) must be paid to BMTA (with no subsidy)- Motor and compulsory third party insurances must be provided to passengers incase of accidents- Drivers have to follow Land Transport Act B.E. 2522 (1979) for driving disciplines

Public Transport in Bangkok: A Case of the Passenger Vans

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December 2007, Dhaka, Bangladesh

2.3

Stakeholders in the passenger van services

Before the regulations were enforced four stakeholders, i.e.,
passengers, drivers, investors and influential figures, were involved in thepassenger van services. The investors set up terminals, determine routes
between city centres and suburbs, and control the services including numberof drivers, fare collection, schedules and other general rules. They behaved
as unofficial regulators and required supports from the influential figures
who received kickbacks in return. Main role of the influential figures was
negotiating with government agencies related to bus transport. Drivers wererequired to pay entry fees (20,000- 100,000 baht) and membership fees
(2,000- 4,000 baht/month) to the investors in order to provide services at theterminals (Eamsupawat, 1999). The passengers were not protected in case of
accidents and overcharge since the services were not regulated.
After the passenger van regulations were enforced the investors, who
registered as passenger van companies, continue to manage the services
through terminal managers and the influential figures remained in theindustry. The entry fees were changed to 10,000 - 250,000 baht and monthly
membership fees were 4,000- 5,000 baht based on number of passengers on
the routes (Longji, 2003). Main stakeholders in the passenger van services
are the passengers, the drivers, the investors (unofficial regulators), theinfluential figures and the government agencies, as shown in Figure 1. At
present, one passenger van route normally comprises one group ofindividual drivers (owner, renter and unlicensed drivers) and is unofficiallycontrolled by one investor and influential figures.
Monitors the services

DLT (A Regulator)

Influential Figures

BMTA (A Regulator)

BribesThe Investor and a terminal manager(An Unofficial Regulator)
Entry & Membership Fee
Operating costs

RenterDrivers

Concession Fee(The rented vans)

Entry & Membership Fee
Operating costs

Rent

Unlicensed
Drivers

Public Vehicle Tax(The rented vans)

OwnerDrivers

Public Vehicle Tax

Concession Fee

Supervise the drivers
Fares
Passenger Van Users
One Passenger Van Route(One group of drivers)

Figure 1: Relationship of the stakeholders in the passenger van services

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2.4

Potential competitors of the passenger vansCompetitions in the passenger van services were assumed at twolevels, on route level and on corridor level, as presented in Figure 2. On
route level, since a passenger van route comprised of several licensed andunlicensed drivers, each driver considered himself as a small enterprise andattempted to balance his costs and revenues to get maximum profits, andthen potential competitors of a passenger van driver were other licensed andunlicensed drivers who operated on the same route.
On corridor level, passenger vans provide similar services to otherroad-based public transport modes. Leopairojna and Hanaoka (2005)
compared Bangkok residents data for their household incomes, mode usage,
and household vehicle availability with data of respondents on passengervans in term of their household incomes, and found that the passengers on
BMTA a-c buses and on passenger vans had the same levels of householdincomes and vehicle availability. The authors concluded that the potential
competitors of passenger vans were BMTA a-c buses.
On Corridor Level

On Route Level
Competition

Licensed van

Unlicensed vanCompetition

Competition

Licensed vanCompetition

CompetitionBMTA
a-c Buses

Unlicensed van

Figure 2: Assumption of Competitions in the Passenger Van Services

3.

ANALYSIS OF THE PASSENGER VAN MARKET

To study market structure of passenger vans, the stakeholders wereidentified as the supply and demand sides. Supply side included the drivers
and terminal managers, i.e., representatives of the investors or selected by
the drivers, and demand side included the passengers on the passenger vans
and a-c buses.
One reason that makes the government judges passenger vans ascompetitor of the BMTA buses is duplication of routes between both
services. To verify competition between the passenger vans and a-c buses,
case study areas were selected by comparing alignments of the passenger
van and a-c bus routes. There were only three corridors that the two modes
have the same origins and destinations and parallel alignments and thus,
selected as case study areas.
Questionnaire survey was done to collect information on the supply
side in terms of characteristics of the routes, the services and the drivers.
Driver opinions related to the existing passenger van regulations and thefuture deregulated industry were interviewed. On the demand side,

Public Transport in Bangkok: A Case of the Passenger Vans

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December 2007, Dhaka, Bangladesh

information related to characteristics of the respondents and their trips,
mode selections and opinions regarding the passenger van and a-c bus
services, and the existing passenger van regulations were obtained. Conjoint
analysis was applied to find whether preferences of the respondents on thepassenger vans and a-c buses were similar or different.
3.1

Analysis of the supply side

In November 2004, 42 drivers were interviewed on one corridor and it
was found that they separated into two groups due to their internalarguments (Leopairojna and Hanaoka, 2005). The two groups agreed tooperate on the same route alignment, share the same terminal in the city
centre and charge the same fare structure. However, there were conflicts
between the two groups due to driver’s misbehaviour, such as picking up
passengers from bus stops and racing. The conflicts lead to fighting andlawsuits. In April 2005, 29 and 40 drivers on other two corridors wereinterviewed. There was no conflict among the drivers on the two corridors
since they were members of the same groups. Some unlicensed vans were
found during the survey.
The drivers preferred this job due to good income, flexibility, comfort
and self-employed attribute. In the survey, the drivers were asked about
their costs, revenues and incomes. Their incomes were high for their
qualification because they earned 300-1,500 baht/day while minimum wageof labours in Bangkok was 170 baht/day and a new graduate earned about
7,000 baht/month in public sector. The data was used for calculating markup on cost.
Mark-up on cost is a ratio of price to marginal cost. The formula forthe mark-up on cost is expressed as:
P − MCm=(1)
MC
Where m is the mark-up on cost, P is the product price, and MC is themarginal cost. In this paper, P was revenues that a passenger driver earned
from operating one trip and MC was marginal cost that the drivers spent tooperate one trip including fuel costs, toll fees, and maintenances. From
Table 2, the mark-ups on cost on the three corridors were varied from 63 to
89 percent, which were high values. This indicates that the fare was highand the passenger van services were low elasticity of demand, which means
imperfect competitive market such as oligopoly.
Table 2: Mark-up on cost on the three corridors
Corridors
A
B
C

636

Licensed Passenger Van Drivers
89 percent
63 percent
72 percent

Year
2004
2005
2005

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Since the passenger van services had high mark-up on cost, the drivers
may reduce the fares but they did not. When oil prices increased to almost
double during 2004 to 2006, the regulated fares of the passenger vans onthese corridors were slightly changed. In addition, the passenger van drivers
receive no subsidy from the government. Conversely, mark-ups on cost of
BMTA a-c buses were negative value because of providing cheap fares.
Although BMTA is subsidized by the government, BMTA increased the a-c
bus fares on many times when oil prices were increased. DLT data showsthat the a-c bus fares increased by 3 baht, from 8-16 baht in 2004 to 11-19
baht in 2006, while passenger van fares increased by 2 baht. The increase ina-c bus and passenger van fares were not so different but BMTA earned
more revenues per trip due to higher vehicle seat capacity. Passenger vansnormally carry 14 passengers, while the a-c buses have regulated capacity of
46 seats and 30 standees.
Passenger van drivers did not consider the BMTA a-c buses as theircompetitors because they thought their passengers were not the same
attributive groups with the a-c bus passengers and they provided different
qualities of services. However, BMTA and its joint-operators responded topopularity of the passenger vans by improving their services, such asrevising their route alignments, providing better condition buses and giving
discount to specific group of passengers to attract more passengers.
During the survey, the authors found that numbers of the passengervans operating on the three corridors were less than numbers of thepassenger vans in the allotted quota. The drivers revealed that some drivers
moved to other routes or temporarily stop operating and some passengervans were under repairing. This finding shows that the drivers observed
demand on each route and moved to routes that provided more income tothem. However, they did not reduce fares even if it is possible. To get
maximum revenues, the drivers wait to occupy full seats before departing
the terminals or attempt to get more passengers from bus stops along theirroutes during off-peak hours. During peak hours, though the frequency wasincreased, passengers waited in long queues at terminals due to insufficientnumber of the passenger vans.
The drivers agreed that main problem in operating the passenger van
services was unfair competitions with the unlicensed vans. The competitions
were unfair since the licensed drivers, who own the passenger vans, had
higher costs in paying insurances, BMTA concession fee and DLT taxes.
Most of the drivers wanted the unlicensed vans to be eliminated but somedrivers recommended solving this problem by licensing the unlicensed vans
and allowing them to operate on other new routes to reduce competitions.
3.2

Analysis of the demand side

Questionnaire survey of passenger van and a-c bus passengers was
conducted on three corridors between April and May 2005. Total 726
respondents- 348 and 378 respondents boarding on the passenger vans andPublic Transport in Bangkok: A Case of the Passenger Vans

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December 2007, Dhaka, Bangladesh

a-c buses completed the questionnaires, respectively. Results of the survey
showed that majority of the respondents on the passenger vans were females(63%), working adults (51%) and 21- 30 years old (41%). They weremiddle-income class, household incomes higher than the average of
Bangkok (57%) and had private vehicles (83%) but they had no personalvehicles (64%). The main trip purpose was to work or attend schools (51%)
and travelling distance was the whole routes (78%).
For the respondents on the a-c buses, percentages of male and female
respondents and age groups, that were younger than 20 years old and 21- 30
years old, were not so different. Majority of them had families withhousehold incomes higher than the average of Bangkok (47%) and had
private vehicles (82%) but they had no personal vehicles (68%). The larger
proportion of them was students (62%) who travelled by the a-c buses towork or attend schools (49%) and travelling distance was shorter than halfof the whole routes (50%).
Chi-square test shows that, at 95% confident level, distributions ofhousehold incomes, household vehicles and trip purposes of the respondents
on the passenger vans and a-c buses were not different. Distributions ofgenders, age groups, occupations, and frequencies of travel were different
but these characteristics were not significant. It was concluded that the
respondents on the passenger vans and a-c buses were in the same attributegroups who had household incomes higher than the average householdincome of Bangkok and had private vehicles in their households but usedpublic transport for commuting or going to school.
In mode selection surveys, under assumption that these passenger vanroutes stopped operating, 73% of the respondents on the passenger vanswould change to the a-c buses. Under assumption that the passenger van
fares were increased, 51% would continue travelling by the passenger vans
while 37% would change to the a-c buses. For the respondents on the a-cbuses, under assumption that these a-c bus routes stopped operating, therespondents would change to the passenger vans (53%) and non a-c buses(29%). Under assumption that the a-c bus fares were increased, 62% ofthem would continue travelling by the a-c buses while 22% and 10% wouldchange to the passenger vans and non a-c buses, respectively.
The respondents on the passenger vans and a-c buses were asked fortheir opinions about regulated fares, planned service schedules, consistencyof planned and actual schedules, allowing passenger van drivers to pick up
passengers from bus stops along routes, and over regulated capacity. Chisquare test shows that, at 95% confident level, distributions of opinions of
the respondents on the two modes were not different. Majority of themagreed that new passenger van drivers should be allowed to register for the
licenses without limitation of the passenger van quota because number of638

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the passenger vans need to be increased to meet demand of the passengers,
it would provide more alternatives for the passengers, the passengers would
be protected and it would lead to competition in terms of fare reduction andquality improvements.
For preferences of the respondents, conjoint analysis showed that the
respondents on the two modes had similar preferences. Their major
concerns in selecting their modes were comfort (seat availability),
convenience (no transfer to other vehicle(s) to complete the trips) and shorttravelling time while prices (fares) were considered but not of importance.
Although their preferences were similar but they selected different modes
due to some other reasons, such as they selected the a-c buses when they
were travelling only on some parts of the route, their origins or destinations
were not served by the passenger vans and they were uncomfortable withnarrow space of the passenger vans.
3.3

Market structure of the passenger van services

Based on characteristics of market structures by the view points of
Producers (operators), Users (passengers), Entry Barriers, Products andServices, and Relationship of the operators, the market structures of thepassenger vans on route and corridor levels were imperfect competitivemarkets. Comparing characteristics of the passenger van services with theimperfect competitive markets revealed that characteristics of the passengervans on route level are mixed between oligopoly and monopolisticcompetition markets, while characteristics of the passenger vans at corridor
level are similar to an oligopoly market.
On route level, data from the supply side shows that a passenger vanroute comprised many drivers and they considered themselves as small
firms. They had many middle-income passengers. Their services wereseparated as licensed and unlicensed services. Entry of driver was controlled
by the investor entry fee and the government entry regulation. To get
maximum profits, the drivers agreed to charge the same fares, i.e., themaximum regulated fares since they do not want to compete each other.
Actions of a driver such as improving vehicle conditions have negligible
effects on incomes of other drivers because passengers waited for apassenger van in a queue and boarded on any passenger van without
considering vehicle conditions. Data from the demand side shows that the
respondents considered the passenger van drivers as the same operator(s)provided similar express services with guaranteed seats. Therefore, market
structure of the passenger van services on route level is considered as
oligopoly with an implication of collusion, as shown in Figure 3.
On corridor level, data from the supply side shows that one corridor
comprised of two main groups of producers, the passenger van drivers and
BMTA with its joint-service operators. The passenger van drivers claimed
that their passengers were in different attribute group compared to the a-c
bus passengers. However, passenger characteristics in this study show that

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December 2007, Dhaka, Bangladesh

the respondents on the passenger vans and a-c buses were in the same
attribute group and had similar opinions and preferences. The passenger van
operators and BMTA provided similar but not identical services, i.e. both
services provide vehicles with a-c but the passenger vans offered express
services with guaranteed seats and higher fares while BMTA buses provide
slow services with not guaranteed seats but cheaper fares. Popularity of thepassenger van services encouraged BMTA to improve their services, butthere was no price competition. Data from the demand side shows that the
respondents selected to travel with either BMTA a-c buses or the passengervans based on comfort, convenience, travel time and their origins anddestinations. Mode selection survey shows that the respondents considered
the passenger vans and a-c buses as substitutes. Therefore, market structureof the passenger van services on corridor level is considered as oligopoly
with implication of product differentiation, as shown in Figure 3.
On Route Level

On Corridor Level“Collusive Oligopoly”“Oligopoly - Product Differentiation”

Licensed Van

Collusion

Unlicensed vanNonprice Competition

Collusion

Licensed Van

Collusion
CollusionBMTA
a-c Buses

Unlicensed van

Figure 3: Market structure of the passenger van services

4.

CONCLUSION

Market analysis of the passenger van services under the existing regulations
showed that there was no price competition at the route and corridor levels.
On the route level, the passenger van market was an oligopoly market with
implication of collusion. At the corridor level, the market was an oligopoly
market with implication of product differentiation. It was observed that theexisting entry regulation initiated collusion in the services. Negative impacts
of collusion on the passengers of the passenger vans were also observed.
The main negative impact was remaining of unlicensed passenger vans.
Therefore, removing the passenger van quota, i.e. deregulating only theentry regulation while maintaining maximum prices and safety regulations,
was recommended to allow the unlicensed passenger vans to get the licenses
and the passengers would be protected in case of accidents.
REFERENCES
Office of Transport and Traffic Policy and Planning (OTP)., 2004.
Transport data and model center II (TDMC II), Bangkok, Thailand.
Department of Land Transport (DLT)., 2003. A summary of passenger vansregulating in Bangkok and neighbouring provinces. Ministry of Transport,
Thailand. (In Thai)

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Leopairojna, S. and Hanaoka, S. (2005). Market structure of passenger vansin Bangkok. Journal of the Eastern Asia Society for Transportation Studies
6, 4192 - 4207.
Eamsupawat, B. (1999). The factors affecting the transportation pattern of
van pooling in Northern Bangkok Metropolis. CU Master Thesis ISBN 974334-801-8, Chulalongkorn University (CU), Bangkok, Thailand. (In Thai)
Longji, S. (2003). A study of bribery in passenger van business.
People's Fund for Exposing Corruption (PFEC), Bangkok, Thailand. (InThai)

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New Technologies for Urban Safety of Mega Cities in Asia

EVALUATION OF EFFECTIVENESSOF PEDESTRIAN OVERPASSES INDHAKA METROPOLITAN
DR. MD. MIZANUR RAHMAN
Bangladesh University of Engineering and Technology,
Bangladesh
MUHAMMAD ASHIKUL ISLAM
Bangladesh University of Engineering and Technology,
Bangladesh
MD. KAMRUL HASAN RIZVIBangladesh University of Engineering and Technology,
Bangladesh
ABSTRACT
A study had been carried out to evaluate the effectiveness ofpedestrian overpasses in Dhaka metropolitan, the capital city of Bangladesh.
An investigation was carried out on five major overpasses at five different
locations of Dhaka metropolitan namely, New Market, Farmgate, Shyamoli,
Mirpur-10 and Airport. Data were collected through a questionnaire survey
among the overpasses user and also the pedestrian who violated traffic
rules and not using the overpasses.
The overpasses of the selected locations were analyzed according to
the collected data to evaluate the effectiveness in terms of their usage. The
highest percentage of pedestrias, using overpass (85%) was found at
Farmgate while thes highest percentage of pedestrians not using overpass
i.e. violators (65%) was found at Shyamoli. The pedestrian interview data
revealed that the reasons for not using the overpasses are as follows: time
consuming (54%), hard to climb up (13%), lack of enforcement (6%), notsecured at night (7%), obstacle by hawkers (6%). The level of service
standard and the capacity of the selected overpasses were also determinedin this study.

1. INTRODUCTION
In context of Bangladesh, pedestrians form the largest single road usergroup. This is primarily because of lack of sufficient transportation facilities
and poor economic condition of the people. Increasing urbanization tends togenerate, additional traffic volume and hence the pedestrian problems
associated with their movement. Many Asian cities have made only 5 to
10% of their urban areas available for transportation facilities, as against 20
to 30% of the urban areas in Western cities. Under this circumstance, there
are inadequate transportation facilities for both vehicular traffic and643

December 2007, Dhaka, Bangladesh

pedestrian traffic. As a result, the vehicular traffic have had to force their
way through narrow, unpaved streets as such the pedestrian traffic have to
face different types of difficulties during their movement.
In uncontrolled traffic area it was observed that pedestrians try to
cross the roadway across the travel way haphazardly. This type of
movement can be reduced to some extent with the provision of pedestrian
facilities such as zebra crossing, pedestrian overpass, pedestrian underpass
etc. The regulation and control of pedestrians is an important factor thatmust be considered in the context of overall urban and transportation
planning and management process. Being physically unprotected,
pedestrians are the most vulnerable group. A large portion of the pedestrian
community is either young or elderly each of which has specific problems
associated with their respective group. These problems involve either thelack of fully developed facilities or a reduction in optimum facilities due tothe aging group.
Hoque (1981), conducted a study on accident type analysis in Dhaka
metropolitan and found that, the pedestrian involve accidents constitute thelargest category of accident type accounting for about 17% of the total
accidents. It is evident that pedestrian accident while crossing the roads isthe greatest problem in Dhaka metropolitan. This had clearly indicated thatthe problem is associated with ignorance of right of pedestrians as well as
the lack of road sense of the road users. It was also observed that thepedestrian crosswalks are missing at locations where these are urgently
needed because of extensive pedestrian movements. This had necessitatedstudying the behavior of driver and pedestrian to assess their attitudes
towards development of effective measure of safe movements with least
interference. Examination of all pedestrian accidents by hour of day
disclosed two distinct peaks during 8 a.m. to 10 a.m. with a later peakduring 4 p.m. to 8 p.m. This showed the little early peak hour to pedestrian
accident in morning compared to that of all accidents. This is primarily due
to the reason of greater pedestrian activities at this hour particularly for thegeneration of trips to schools, markets, as well as to work. The pedestrian
movement and characteristics therefore need to be well studied. This task is
not so simple and need considerable research towards development ofeffective devices for the mobility and safety of pedestrians.
The various types of pedestrian facilities that have already been usedthrough out the world are basically to ensure safety and comfort for thepedestrians. These facilities may be classified into three major groups;
depending on whether or not pedestrian and vehicle are separated (Victor,
1979). Integrated systems are currently adopted system with side walkprovided parallel with the carriageway and cross walks provided at intervals(Zebra crossing, Signalized Zebra crossing, Side walks, Islands). Horizontal
separation system located away from the vehicle network accommodates
pedestrian movement along pathway that is interdependent on vehicularpath (Widened sidewalk, Full malls, Auto free zones, Displaced grids).
Vertical separation system is perhaps the most efficient system. The three644

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primary elements of vertical separation are: Underground, Elevated and Atgrade system. In this system conflict with other road users are eliminated.

2. CHARACTERISTICS OF DATA COLLECTION SITESIn the Dhaka metropolitan area a number of overpasses have been installedat different locations on the basis of necessity of pedestrian crossing. All
these locations are not equally important according to the volume of thepedestrian. In order to select the locations of the pedestrian overpasses thefollowing factors are considered: importance of the location, amount ofpedestrian volume and suitability for the study. In this way five locations
were selected for this study (NewMarket overpass, Shyamoli overpass,
Mirpur-10 overpass, Farmgate overpass and Airport overpass). All theselocations are important and busy areas. Different kinds of people move tothese place for a lot of purposes. New Market is always filled with a lot ofbuyers. Farmgate is the center of Dhaka city, where a lot of commercial
activities always take place. Shyamoli is newly developed busy region witha mixed land uses area. Mirpur-10 has a very important intersection and Zia
International Airport is very important for its air navigation facilities.
Amount of pedestrian volumes at these locations are significant as well assuitable for the study. The locations of these overpasses are shown in
Figure 1.

Figure 1: Locations of Study Area on Dhaka City’s Map

Evaluation of Effectiveness of Pedestrian Overpasses in Dhaka Metropolitan

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The characteristics of study locations are presented in Table 1.

Name of

Table 1: Characteristics of data collection site
Location
Width of
Height ofPedestrian

Overpass

Overpass

Overpass

volume(ft)(ft)(ped/hr)

New market

Dhanmondi

9.5

18

318

Shyamoli

Mohammedpur

9.5

20.5

179

Mirpur - 10

Mirpur

9.0

21

385

Farmgate

Tejgaon

10.0

20.6

649

AirportCantonment

11.0

21

581

Two types of data are collected for this study. To observe thepedestrian behavior pedestrian volume is counted in two groups, using
overpass and not using overpass. All data were collected at morning peak (7AM to 10 AM) and evening peak (4 PM to 7 PM) for three working days.
To gather the pedestrian’s views a questionnaire survey was conducted at all
the selected sites. The pedestrian opinion survey is an important componentof this study. The purpose of this is to find out the causes of not using theexisting overpasses. For this purpose about 500 pedestrian were interviewed.
The method used was random sampling. A prepared questionnaire was used
to interview pedestrians.

3. PEDESTRIAN BEHAVIORAt the selected locations to observe the pedestrian behavior numbers ofpedestrians were counted in groups of those using overpass and not using
overpass. This data were recorded on hourly and gender basis. Table 2
presents the flow characteristics of pedestrians.
As shown in Table 2, the highest proportion of pedestrians using
overpass was at Farmgate location (85%) followed by Airport location(79%) and the maximum number of pedestrians not using overpass was at
Shyamoli location (65%) followed by New Market location (57%). At
Mirpur-10 location 60% pedestrians were using overpass. From the fieldobservation it was evident that at Farmgate location pedestrians were forced
to use overpass as there are fencing all around the roads at this site. At
Airport location the average speed of vehicles is too high for pedestrians tocross the road, and the width of the roads at this site is high which forced
pedestrians to use the overpass. The maximum number of female
pedestrians using overpass was found at New Market, Shyamoli and Mirpur–10 locations. At New Market there are various markets which attracts

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women, on the other hand at Shyamoli and Mirpur –10 locatons there are lotof garment factories so garment workers are using the overpass. Also at
Mirpur-10 location there are maximum number of female pedestrians who
not using the overpass.
Table 2: Pedestrians Flow Characteristics at Study Sites
Name of
Pedestrians using overpass
Pedestrians not using
overpass

overpass
Male

Female

Total

Male

Female

Total

New

1301

611

1912

2143

391

2534

Market

(68%)

(32%)

(43%)

(85%)

(15%)

(57%)

Farmgate

3629

263

3892

657

51

708

(93%)

(7%)

(85%)

(93%)

(7%)

(15%)

721

351

1072

1805

187

1992

(67%)

(33%)

(35%)

(91%)

(9%)

(65%)

1549

759

2308

1186

322

1508

(67%)

(33%)

(60%)

(79%)

(21%)

(40%)

3097

389

3486

1169

137

1306

(89%)

(11%)

(79%)

(90%)

(10%)

(21%)

Shyamoli

Mirpur -10

Airport

4. PEDESTRIAN VIEW
In general, pedestrians tend to walk along a path that represents the shortest
distance or most convenient route among several routes. They often cross at
mid-block instead of using overpass or underpass. In this study, thepedestrians for different locations have their own point of view for not using
the overpass. The reasons are: time consuming, hard to climb up, no medianfencing, not so secured specially at night, physically not fit, risky for
movement, obstacle by hawkers, vendor and so on. Table 3 presents thecauses for not using overpass by pedestrians.
From Table 3 it is found that the highest percentage of pedestrian(54%) is not interested to use overpass just because of more time required tocross the road. Other reasons are: hard to climb up (13%), lack ofenforcement (6%), not so secured at night (7%), physically not fit (5%), no
median fencing (5%), obstacle due to hawker (6%).

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Table 3: Cause for not using the overpass by the pedestrian
CausesNew
Farm- Shya Mir Air- Total
marketgate-moli pur- port
10
Time
50
51
47
79
69
296
Consuming
Hard
to
0
37
17
11
6
71
climb up
Lack
of
0
16
0
11
5
32
enforcement
Not so
7
0
16
13
0
36
securedspecially atnight
Far away
0
0
0
0
19
19
Physically
5
3
14
5
1
28
not fit
No median
28
0
0
0
0
28
fencing

(%)

54
13
6
7

3
5
5

5. CAPACITY OF OVERPASS AND LEVEL OF SERVICE
The actual capacity of an overpass can be determined using the informationof pedestrian speed and pedestrian module. The formula established so isgiven below.
Width(ft)*Speed(ft/min)*60
Capacity/Hour =Pedestrian module(ft2/ped)(HCM, 2000)

Table 4: Theoretical Capacity and Level of Service
Location Width Observed
Theoretical
Level
Pedestrian(ft)
Capacity
range ofof
Module/Hr
Capacity/Hr Service(ft2/ped)
New
9.5
318
Below 1140
A
130
MarketFarmgate

10649

Below 1200

A

130

Shyamoli

9.5

179

Below 1140

A

130

Mirpur-10

9385

Below 1080

A

130

Airport11

581

Below 1320

A

130

In this study the flow volume of the pedestrian, those using theoverpass and the violators who are not using it were recorded. The level ofservice standard and capacity were determined to know about theserviceability. These parameters are functions of the width of the overpass.

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Therefore, the capacity per hour corresponding to level of service wascalculated for different widths of the overpass as found in the study.
Observed volume of pedestrian that uses the overpass had been comparedwith the theoretical capacity to find the level of service and pedestrian
module thereafter. The results are presented in Table 4.
Table 4 shows that a level of service standard A is maintained in all
five major overpasses during the peak hour. This may be due to the reason
that most of the roads do not have continuous median barrier and overpasses
are not adjacent to the intersection. Pedestrian get a wide area to cross theroad illegally. That’s why, a level of service standard A is found, even in thepeak hour.

6. FIELD OBSERVATIONSAt New Market, only 43% are using the overpass and the rest 57% are notusing it. It reflects that pedestrians at this point tend to cross the road under
the overpass since median fencing is not continuous. People prefer the
shortcut under the overpass whereas all the stairs to climb up the overpass isheavily crowed. At Farmgate, median fence is continuous and pedestrian
have very little opportunity other than using the overpass. At Shyamoli, only
35% pedestrians use the overpass just because of a wider area of crossing.
Similarly, some of the pedestrians cross the road by the roundabout at
Mirpur-10. Median fencing is continuous at Airport, but people crossthrough the intersection just in front of the airport. The following images
display some scenario and overpass condition of Dhaka City.

Figure 2: Pedestrian crossing the road illegally during green period(Farmgate)

Evaluation of Effectiveness of Pedestrian Overpasses in Dhaka Metropolitan

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December 2007, Dhaka, Bangladesh

Figure 3: Random crossing interrupts the vehicular flow (Newmarket)

Figure 4: Pedestrians are chasing vehicle under new market overpass

Figure 5: Pedestrians like shortcut rather than using the overpass

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7. CONCLUSION
The overpasses of the selected location are analysed according to thecollected data to evaluate the effectiveness in terms of their usages. The
percentage of pedestrian using the overpass and the number of violators are
determined at each location. The investigated regions are NewMarket,
Farmgate, Shyamoli, Mirpur-10 and Airport. The result of the studies on the
overpasses has been discussed so far. This result on the effectiveness of theoverpasses may lead to a better design of the overpass facilities in the future.
Based on the study, the following conclusions are made:
•
•
•
•
•
•

The overpass user is maximum at Farmgate which is around 85%,
whereas it is minimum at Shyamoli which is only 35%.
In most of the location, pedestrians get the opportunity andindependence to cross the road according to their wish.
From the field study, it is evidenced that male pedestrians are moreencouraged to use overpass rather than female pedestrians.
The higher the opportunity to alter the way other than overpass, thelower the number of pedestrian using the overpass.
It is observed by the study results that reluctance to use the overpass
is higher when the amount of time needed to complete the overpass
is long.
Level of service standard is A for all the five overpasses, whichshowed that the overpasses are flowing less than the capacity

8. RECOMMENDATION
Some drawbacks and limitations were chalked out while carrying out the
study. Analyzing the data it was found that the reasons are the absence ofmedian fencing, lack of intention to use the present facilities, less awarenessabout the safety. From the above viewpoint, to get a better performancefrom the pedestrian and to make the best possible use of the overpasses thefollowing recommendations are made.
1. Locations of the overpasses have to be eventually distributed.
According to the engineers of Dhaka City Corporation, somepolitical and other influence sometimes shifts the overpass from therequired location. So the location should be selected as per thenecessity of the location.
2. In maximum areas, pedestrians get the opportunity andindependence to cross the road according to their wish. So most ofthem can consider overpass use as time consuming. Therefore,
continuous median-barrier is a way to improve the usage of overpass
effectively.
3. As we do not have required number of overpasses, the least used
overpasses can be shifted to an important location having moredemand of an overpass.

Evaluation of Effectiveness of Pedestrian Overpasses in Dhaka Metropolitan

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December 2007, Dhaka, Bangladesh

4. Road safety education is necessary for every road user to behave
better as a pedestrian and to increase the intention to use the existing
facilities to be safer.
5. Maintenance work of the overpass should be carried out in a regularmanner and cleanliness should be checked daily.
6. Enforcement should be used to wipe out the hawkers and the mobile
shops on the overpasses that creates obstacle to the pedestrians.

REFERENCES
Abraham, P.C. (1974), An Urban Transportation Planning
Methodology for Developing Countries: A Thesis, Asian Institute ofTechnology, Bangkok, Thailand.
Fruin (1970), Designing for Pedestrians, A Level of Service Concept,
Dissertation, Polytechnique Institute of Brooklyn, January, 1970.
Hasib, M.M. (1990), A Study of Mass Transit in Metropolitan Dhaka,
A Thesis, Department of Civil Engineering, Bangladesh University ofEngineering and Technology, Dhaka.
Highway Capacity Manual (1985), Transportation Research Board
Washington D.C.
Hoque, M.M. (1981), Traffic Accidents in Dhaka: A Study on
Roadway, Safety, Research Report, Bureau of Research Testing andConsultation, Bangladesh University of Engineering and Technology,
Dhaka.
Hoque, M.M. (1981), Pedestrian Accidents and Road Users Behavior:Some research Findings in Dhaka City. Paper Presented at the 26th Annual
Convention in the Institute of Engineers, Bangladesh.
Paul H. Wright, Radnor J. Paquette (1979), Highway Engineering, 4th
EditionPeter J. Moses (1990), The Vulnerable Road Users- The Pedestrian:th
6 Road Engg. Association of Asia and Australia, Conference Proceeding,Vol. no. 2, 1990.
Victor, D.J. (1979), Facilities for Pedestrian and Cyclists: Advanced
Course on Urban Transportation Management, Department of Civil
engineering, Indian Institute of Technology.

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New Technologies for Urban Safety of Mega Cities in Asia

ROAD TRAFFIC ACCIDENTS AND
INJURIES: A SERIOUS SAFETY CONCERN
IN URBAN AREAS OF BANGLADESH
MD. MAZHARUL HOQUE
Professor, Department of Civil Engineeringand Director, Accident Research Centre (ARC)
dirarc@arc.buet.ac.bd
SHAHNEWAZ HASANAT-E-RABBI1 and S. M. SOHEL MAHMUD2
Research Assistant, Accident Research Centre (ARC)
romel157@yahoo.com
CHOWDHURY KAWSAR AREFIN SIDDIQUI1and SABREENA ANOWAR2
Junior Research Fellow, Accident Research Centre (ARC)kawsar_arefin@yahoo.com
ABSTRACTThe combination of rapid urbanization and motorization has been a
key cause of numerous transport problems in developing cities in Asia. It
has resulted in deterioration in accessibility, service levels, safety, comfort,
operational efficiency, and the urban environment. This is particularly
prevalent in Bangladesh with current urbanization level at around 25
percent. Urban road traffic accidents and resulting deaths has now emerged
one of the major safety problems in urban areas all over the world. In 2002
nearly 1.2 million people worldwide died as a result of a road traffic crash.
This represents an average of about 3300 persons dying each day aroundthe world. In addition to these deaths, between 20 million and 50 million
people globally are estimated to be injured or disabled every year. The
majority- around 88 percent- occurs in the so-called developing andemerging countries. Accident rates in developing countries are often 10 to
70 times higher than in developed countries. The vast majority of roadaccident fatalities comprise vulnerable road user viz. pedestrians, bicyclists
and motor cyclists, and they are most prevalent in urban areas. The roadsafety problems appear to be much more severe than the other violent
causes and natural disasters. With the increasing complexities of urban
roads and transport problems it is clear that one of the today's biggest
challenges of transport engineering professionals is to address the issues ofurban road safety with due urgency. This paper presents an overview of thescale and characteristics of the road traffic accident and injury problem indeveloping countries, with a special reference to the situation in urban
areas in Bangladesh. The paper in particular highlights the contemporary
road safety issues and the commensurate solution strategies for achieving
sustainable and safer urban transportation system in Bangladesh with due
regards to the needs and requirements for safety of vulnerable road users,
pedestrian in particular.

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December 2007, Dhaka, Bangladesh

1. THE PROBLEM OF ROAD TRAFFIC ACCIDENTS AND
INJURIES
1.1

The scale of the problem

In 2002 nearly 1.2 million people worldwide died as a result of a roadtraffic crash. This represents an average of about 3300 persons dying eachday around the world. In addition to these deaths, between 20 million and 50
million people globally are estimated to be injured or disabled every year.
Around 88 percent of those deaths occur in the developing world (Mackay,2003), even though these countries only account for 32 percent of the total
motor vehicle fleet worldwide (Hoque et al, 2001). For every death, there
are far greater numbers of injuries- four persons with severe/permanent
disabilities, ten persons requiring hospital admission, and thirty persons
requiring emergency room treatment. It is estimated that road traffic injuries
will be the third leading cause of life years lost by 2020 (Table 1). Indeed,
they are the second leading cause of death for people aged 5 to 25, withdevastating impact on families and communities. For all these reasons, roadtraffic injuries are an important obstacle to development and place anenormous strain on a country’s health care system, and on the national
economy in general (Ban Ki-Moon, 2007).
Table 1: Change in Rank Order of Disease Burden for 10 Causes(1990-2020)

Source: WHO. Evidence, information and policy, 2000)

Furthermore, according to World Hearth Organization (WHO) datafor 2002, these road traffic accident deaths accounted for 23 percent of all
injury deaths world wide (Figure 1).

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New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

Other
Unintentional
Injuries, 18.10%

Other
Intentional
Injuries, 0.20%

Road Traffic
Injuries, 22.80%

Poisioning,
6.70%
War, 3.40%
Falls, 7.50%
Fires, 6.20%
Drowning,
7.30%

Violence,
10.80%
Suicide, 16.90%

Figure 1: Distribution of global injury mortality by cause (Source:
WHO Global Burden of Disease Project, 2002, Version 1)
Even when deaths by various violent causes are considered, roadtraffic accident is found to be the leading cause accounting for 33 percent,
36 percent and 56 percent of the deaths in developed, developing andMiddle-Eastern countries respectively (Table 2).
Table 2: Fatalities by Violent Causes in different regions
Developing
Developed
MiddleCountries
Countries
Cause
EasternCountries
Fire
2.0
3.0
1.0
Drowning
7.0
2.0
2.0
All other violent
20.0
26.0
26.0
causes
Suicide
9.0
33.0
5.0
Homicide
26.0
3.0
10.0
Road Traffic
36.0
33.0
56.0
Accident
100%
100%
Total
100%
Source: (Jacobs & Palmer, 1996)

The road safety problem appears to be much more severe comparedwith other natural disasters such as earthquake, cyclone, tsunami etc. Table
3 shows a list of some of the major disasters and the resulting fatalities. In
last 35 years, there were ten major natural disasters which claimed about 1.4
million lives with an average 140,000 deaths per disaster while road traffic
accidents alone account for 1.2 million deaths each year of which nearly 50
percent are in the Asia Pacific region with a clear sign of rapid increasing
trends. Therefore, it is obvious that road traffic accidents are more serious
hazards than other natural disasters.

Road Traffic Accidents and Injuries: A Serious Safety Concern in Urban Areas of Bangladesh

655

December 2007, Dhaka, Bangladesh

Table 3: Some major disasters and fatalities in the region
Year Type of natural disaster
Place
Deaths1970 Cyclone
Bangladesh
500,000
1976 Earthquake
Tangshan, China
255,000
1988 Earthquake
Spitak, Armenia
25,0001990 Earthquake
Northwestern Iran 35,000
1991 Cyclone
Bangladesh
140,000
1999 Earthquakeİzmit, Turkey
17,1182001 Earthquake
Gujrat, India
20,085
2003 Earthquake
Bam, Iran
31,0002004 TsunamiIndonesia
283,106
2005 Earthquake
Kashmir
80,000Source: United States Geological Survey (USGS)

1.2

Road traffic accidents in developing countries

The safety situation in developing countries is rapidly deterioratingwith increasing number of road deaths, largely as a direct consequence of
rapid growth in population, motorization and urbanization and lack ofinvestment in road safety. While the road accident situation are slowly
improving in the industrialized societies (e.g. Australia, UK, USA), mostdeveloping countries are experiencing a worsening situation. According to
UNESCAP (United Nations Economic and Social Commission for Asia andthe Pacific) in 2006 more than half a million people were killed (50 percent
of total global fatalities) and 20-30 million injured in road crashes in Asiaand the Pacific region at an economic cost of some US$100 billion.
Whereas highly motorized countries’ (North America, Australia, New
Zealand, Japan and Western Europe) contributes only 12 percent (GRSP).
Accident deaths rates in developing countries are often 10 to 70 times
higher than in developed countries. The vast majority of road accident
fatalities comprise vulnerable road user viz. pedestrians, bicyclists andmotor cyclists, and they are most prevalent in urban areas.
It should be noted that road traffic injuries affect mostly the young andthe middle age people in the society. In the low and middle income
countries and in the South-East Asian region, road traffic injuries are the 6thleading cause of death for all age group (Table 4). From this Figure, it isalso found that road traffic injuries ranked the 1st and 3rd leading cause ofdeath for age group 15-29 years and 30-44 years respectively. These agegroups represent the main working groups for each country.

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Table 4: Leading cause of death in South-East Asian region and other low
and middle income countries
0-4 Years

5-14 Years

15-29
Years

30-44
Years

1

Lower
respiratory
infections
176921
Diarrhoeal
diseases
108636

Diarrhoeal
diseases
18520

Road
traffic
injuries
53535
Tuberculosis37872

Tuberculo
sis
48762

Ischaemic
Ischaemic
Ischaemicheart
heart disease heart diseasedisease31619543006280527
HIV/AIDS Tuberculo Cerebrovascu Cerebrovascul
38965
sis
lar diseasear disease
70260
255251339328

HIV/AIDS
33771

Road
traffic
injuries
36097

2

Lower
respiratory
infections
17790
Childhoodcluster
diseases
16120

3

Low birthweight106415

4Childhoodcluster
diseases
89015
Birth
asphysia andbirth trauma
82122
Congenitalheart
anomalies
43408
Annencephaly18009

Road traffic
injuries
9451

Proteinenergy
malnutrition
9605
Endocrine
disorders
9252

Drowning
3996

5

6

7

8

9

45-59
Years

≥60 Years

Rank

Cerebrova
sculardisease55630

Ischaemic Cirrhosisheartof the liverdisease23607
25369
Tuberculosis
SelfCerebrova Hypertensi
8067
inflicted
scularve heart
injuries
diseasedisease
12521
17801
22826
Hypertensive
Fires
War injuries Cirrhosis
Road
heart disease
6334
12124
of the liver
traffic
87439
16319
injuries
18524
Diarrhoeal Diabetes
Diabetes
War injuries
Lower
diseasemellitus
mellitus
4765
respiratory
13010
18224
66938
infections
8337

Nephritis andnephrosis
2500

Fires
15620

Chronic
obstructive
pulmonarydiseases102826Lower
respiratory
infections
102065Tuberculosis
89129

Ischaemic
heart
disease7278
Rheumaticheart
disease7151

10

Meningitis
8888

Rheumaticheart disease2332

Diarrhoeal
disease6731

11Road traffic
injuries
7891

12

Spina bifida
6479

Congenitalheart
anomalies
2304
Malaria
1831

Nephritis
andnephrosis
6417
Cerebrovasc
ular Disease
6096

13

Alzheimerand other
dementias
5765

Leukaemia
1764

Malaria5727

14

Nephritis andnephrosis
5592

Falls
1753

Interpersona
l violence
5431

15

Drowning
4615

Meningitis
1749

Maternal
haemorrhag
e
4885

Lower
respiratory
infections
12562
War
Injuries
12254

Breastcancer
16358

Trachea,bronchus,
lungcancers
15292
Fires
Lower
10929
respiratory
infections
15263
Nephritis Mouth andandoropharyn
nephrosis x cancers
10088
14990
BreastNephritis
cancerand9413
nephrosis
14898
SelfChronic
inflicted
obstructiv
injuriese9394
pulmonarydiseases
14720
Hypertensi Diarrhoeal
ve heart
diseasesdisease14422
8139
Malaria
Liver
6782
cancer12785

All Ages

Lower
respiratory
infections
332940Tuberculosis
257614
Diarrhoeal
diseases
198178Road traffic
injuries
140405Chronic
obstructive
pulmonarydiseases
123881

Nephritis andnephrosis
37811

Hypertensive
heart disease120571

Diarrhoeal
diseases
36857

Childhoodcluster
diseases
115110Trachea,bronchus,lung cancers
35203
Cirrhosis of
the liver25512

Low birthweight106423Alzheimerand other
dementias
21257
Liver cancer
19982

HIV/AIDS
83099

Mouth andoropharynx
cancers
19391
Asthma18867

Diabetes
mellitus
93782

Birth asphyxia
and birthtrauma82562
Nephritis andnephrosis
77308
Cirrhosis of
the liverSource: Global Burden of Disease Project for 2000, Version 1

Road Traffic Accidents and Injuries: A Serious Safety Concern in Urban Areas of Bangladesh

657

December 2007, Dhaka, Bangladesh

The traffic safety patterns in developing countries are much more
complex than those in developed countries. Among the selected developing
countries, Bangladesh has the lowest level of motorization (2.3), but thefatality per 10,000 motor vehicles is the highest. The percent of decreasing
trends of fatalities per 10,000 motor vehicles is remarkable in Thailand (79%) and Malaysia (-89%) within the period of 1996 to 2003 whereas in
Bangladesh the same index increases about 15 percent during this period(Table 5). The fatality index (deaths divided by total casualties as apercentage) is also highest in Bangladesh (0.7) among the selecteddeveloping countries. It is also revealed that pedestrians are most vulnerable
road user group in developing countries, particularly in Bangladesh.
Table 5: Distribution of Road Accident Fatalities of Selected Developing
Countries with BangladeshCountry
India(2003)
Indonesia(2005)
Nepal(2001)
Sri
Lanka(2005)
Thailand(2002)
Myanmar(2003)
Malaysia(2003)
Bhutan(2005)
Bangladesh (2003)

Fatalities

Motoriz
ation
level

Two/threewheelers(% of total)

Fatality per
10,000
MV

%
Pedes
trian
Fatalities

Percapitafatality
rate

Fatality
index% changeoffatalities /10,000
MV

85998

63

na

12.8

10

8.1

0.21

-37

11610

98

75%

5.1

na

9.5

na

-34

1987

20

65%

42.0

50

8.3

0.06

na

2306

133

60%

9.1

32

12.1

0.05

-48

13116

381

68%

5.3

6

20.4

0.14

-79

1308

22

68%

13.8

na

3.1

0.24

46

6282

651

48%

4.2

na

27.2

0.02

-89

23

13

24%

7.7

59

1.0

0.02

-10

3334

2.3

67%

116

51

2.7

0.70

15.0

Source: World Bank, TRL, ESCAP road safety statistics

1.3

The urban accident problem

Generally, the road accident problem is disproportionally greater inurban areas than in rural areas (Lundebye 1995). This can be seen withrespect to the situation in different cities of developing countries:• Santiago (Chile): With 35% of Chile's population and 43% ofregistered vehicles has about 50% of all accidents.
• Sao Paulo (Brazil): With 7% of Brazil's population and 17% ofvehicles has about 24% of road traffic injuries.
• Harare (Zimbabwe): Accounted for 43% of road accidents with apopulation of 12%.
• Metropolitan Dhaka (Bangladesh): Accounted for nearly 23 % ofreported road accidents with a population of 7.3%.

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New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

Evidence suggested that large proportions of road accidents in cities
are concentrated on the main street network. There are still many
"blackspots" in urban areas which are amenable to site specific treatments.
Up to 70 percent of urban road accident deaths are often pedestrians alone.
For example, according to the latest data, Hong Kong had the highest shareof pedestrian fatalities, representing 67 percent. Pedestrians were involvedin 62 percent of the total fatal accidents reported in Dhaka, 47 percent in the
Republic of Korea, 45 percent in Sri Lanka and 43 percent in Fiji (Ross
Silcock and TRL 1997). Pedestrian were high in Middle Eastern countries,
around 50 percent. The comparable figure for European countries is around20 percent. Motorcycle accidents also have become or are rapidly becoming
a serious problem in some countries, for example in Malaysia, motorcycles
accounted for 57 percent of the fatal accidents and 74 percent of the injury
accidents in 1994.

2. ROAD TRAFFICBANGLADESH

ACCIDENTSAND

INJURIES

IN

According to the official statistics, in Bangladesh there were at least 35833
fatalities and 18029 injuries in 32845 reported accidents from 1998 to 2006.
The number of fatalities has been increasing from 1009 in 1982 to 3830 in
2006, nearly 3.8 times in 25 years period. It is estimated that the actual
fatalities could well be 10000-12000 each year (Hoque 2005).
The statistics revealed that Bangladesh has one of the highest fatality
rates in road accidents. As a consequence of these road traffic accidents, thenation is suffering a huge loss of the order of Tk. 5000 crore/US$ 850
annually, which is nearly 2 percent of country’s GDP. Accident victims aremostly young and middle age people (5-44 years) and they are the mosteconomically active and productive group in the society. These tragic losses
generate serious consequences for family lives of the victims and theeconomy particularly affecting the poor people.
The fatality index in Bangladesh is nearly 70 percent, which is one of
the highest among the developing countries. The fatality index depends
crucially on accurate reporting of deaths and injuries, but can also be
influenced by medical facilities. This signifies probably two importantcharacteristics, viz. the wide spread under reporting of injuries and lessserious accidents and the lower level of emergency medical services. In
Bangladesh, there is little scope to provide the prompt and necessary
medical attention to injured people, particularly soon after an accident. In
passing, it should be noted that about 50 percent of road traffic deaths
happen within 15 minutes of the accident as a result of injuries to the brain,heart and large blood vessels. A further 35 percent die in the next 1-2 hoursof head and chest injuries and 15 percent over the next 30 days from sepsis
and organ failure. The time between injury and initial stabilization is the
single most important factor in patient survival, with the first 30-60 minutes
being the most important. Thus prompt emergency assistance and efficient
trauma care are clearly important in minimizing the road accident deaths.

Road Traffic Accidents and Injuries: A Serious Safety Concern in Urban Areas of Bangladesh

659

December 2007, Dhaka, Bangladesh

Orthopedic hospital reports show that around 56 percent of total
patients in the intensive care units are victims of road traffic accidents.
Moreover, almost 30 percent of hospital beds are occupied by patients
injured by road traffic accidents. During seven days of Eid vacation in
October, 2007 a total 668 patients were admitted in the emergency sectionin Orthopedic hospital. Of these patients 220 (33 percent) were injured fromroad traffic accidents.
3.

ROAD TRAFFIC ACCIDENT SCENERIO IN URBAN AREAS
OF BANGLADESH

During eight years period, from 1998 to 2006, at least 11459 accidents
occurred in urban areas contributing 35 percent of total accidents occurred
within this country. More than 8250 fatalities and almost 6700 injuries
occurred in these accidents which represent around 28 percent of the total
casualties (MAAP 5). Some striking road accident characteristics in urban
areas are briefly discussed in the following sections.
3.1

Pedestrians-the most vulnerable road user group

In Bangladesh, with a low level of motorization, the role of walkmode is quite significant. Pedestrians have received far less attention thanvehicular traffic. Up to 70 percent of urban road accident deaths arepedestrians alone. Their involvement varied between 43 and 73 percent of
the road accident fatalities in the medium sized cities. Pedestrians accounted
for 53 percent of all reported fatalities in the accident database in urban
areas (Figure 2).

Rickshaw
Users, 9%Others, 7%
Motor Cyclists,
4%Bus, Mini-bus,
Micro-bus
users, 10%

Baby Taxi,
Tempo users,
8%
Bicyclists, 4%
Truck, Heav
Truck users,
6%

Car, Jeep, Pickup, 3%
Pedestrians,
53%

Figure 2: Distribution of road fatalities in urban areas of Bangladesh

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New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

Figure 3: Pedestrians-the most vulnerable road user
3.2

Predominant accident types

Event specified accident type analysis showed ‘hit pedestrian’ as thedominant accident type in urban areas, 62 percent involvement in fatal
accidents. Other common accident types are: rear end collision (15%) andhead on collision (8%). These three accident types account for nearly 85
percent of the fatal accidents.
3.3

Accidents at intersections

A large number of accidents occur at intersections. These intersection
locations often become accident black spots. Analysis showed that 31
percent road accidents occur at intersections in urban areas. Of theseintersection accidents 72 percent occurred in Dhaka. In the analysis, a siteexperiencing a total number of 10 or more accidents of all severities during
the study period (1998-2003) was classified as hazardous. A total of 313
intersections (with 2040 accidents) were found where at least one accident
took place during 1998 and 2003. Out of these 313 intersections, 54intersections were identified having 10 or more accidents. These 54
intersections accounted for nearly 79 percent of all intersection accidents
and almost 78 percent of total pedestrian accidents at intersections.

Figure 4: Unregulated pedestrian movements and High intensity pedestrianflow at a major intersection in Dhaka

Road Traffic Accidents and Injuries: A Serious Safety Concern in Urban Areas of Bangladesh

661

December 2007, Dhaka, Bangladesh

3.4

Over involvement of trucks and buses

Studies of road accidents revealed that heavy vehicles such as trucks
and buses including minibuses are major contributors to road accidents. This
group of vehicles is particularly over involved in pedestrian accidents
accounting for about 65 percent (trucks 28%, buses 22% and minibuses
15%).
3.5

Involvement of children in road accidents

The national road accidents statistics in Bangladesh revealed a serious
threat to the children. The incidence of overall child involvement in roadaccident fatalities in Bangladesh is found to be very high, accounting forabout 22 percent. In urban areas, the proportion is about 12 percent. This
involvement of children under 15 years of age in road accident fatalities ismuch higher than those in other developing countries.
3.6

Accident factors

The principal contributing factors of accidents are adverse roadway
roadside environment, poor detailed design of junctions and road sections,excessive speeding, overloading, dangerous overtaking, reckless driving,carelessness of road users, failure to obey mandatory traffic regulations,variety of vehicle characteristics and defects in vehicles such as worn out
tyres, loose wheels, overloaded axle, faulty brake and indicator lighting
system etc. and conflicting use of roads. Incompetent drivers and drivingwith open and widespread use of fake licenses appear to be a major concern
to safety on our roads. Others include a low level of awareness of the safety
problems, inadequate and unsatisfactory education, safety rules andregulations and traffic law enforcement and sanctions.

4.

SOME STRATEGIES FOR SAFETY IMPROVEMENT IN
URBAN AREAS

Considerable safety improvements can be made through road safetyengineering strategies. Strategies for reducing and preventing road traffic
accidents and injuries are many and varied. More common strategies are
exposure control (restrict certain travel and deny access to hazardous
situation), accident prevention (design, construction and maintenance ofvehicles and road system), behavior modification (road user education, thelaw and its enforcement and sanctions), injury control (vehicle design, roadside hazard management) and post-injury management (recovery, treatment
and rehabilitation measures). All of those strategies played a major part inachieving greater safety on the road network. For the future, it is important
to maintain the impetus in such strategies by the introduction of newly
developed measures, approaches as well as technologies.
With particular regard to urban road safety in developing countries,
Bangladesh, in particular, pedestrian vehicle conflicts are clearly the662

New Technologies for Urban Safety of Mega Cities in Asia

ICUS Report 27

greatest problem with significant involvement of trucks and buses. There is
specific need and much scope for road environment improvements aimed atcorrecting the most common deficiencies through wider application of
traffic engineering approaches. It is argued that priorities be placed on theprinciples like traffic segregation to provide facilities and road space for themost vulnerable users particularly pedestrians and non-motorised vehicles,
force correct road user behaviour (self enforcing measures) via
channelisation, speed reduction measures etc. With resource constraints thegreater emphasis should be placed on low cost improvement schemes.
Implementation of such measures should take place at hazardous roadlocations (accident blackspots) identified by systematic accident
investigation (rather than in an ad-hoc manner). To promote enhanced roadsafety, developing countries like Bangladesh should have programs to
implement well known engineering measures, leading to larger and longer
lasting effects at fewer expenses, widely and systematically. Importantly
systematic application of road safety audit- a powerful tool for accident
prevention is considered to be extremely useful and effective in alleviating
the deteriorated safety situation.
4.1

New innovative high-tech solution options

Improved and innovative solutions are vital to reduce road traffic
accidents and casualties. Such as safety barriers and crash cushioning(energy absorption system) at increased impact speeds are highly effective
in savings lives. Improved road markings could guide motorists and reduce
casualties. Advanced road side management system (fixed objects, trees,
poles etc.) and high-tech solutions such as Intelligent Transport System(ITS) can reduce overall hazards by a big margin. The ITS is intended foradvances in navigation systems, assistance for safe driving, optimization of
traffic management and increasing efficiency in road management bybuilding an integrated system of people, roads and vehicles utilizing
advanced data communication technologies. While providing users withquick information required for their safe and comfortable travel in ways
easy to understand, ITS makes it possible for users to enjoy a high leveltransportation system and thus reduce much of the workload commonly
associate with driving and thereby accomplish a major improvement in roadtransport safety. A recent study on ITS application for Bangladesh revealed
that with 100 percent deployment of ITS technology, the fatal and injury
related accidents could be reduced as much as 26 percent and 30 percent
respectively (Hoque 2001).

5.

CONCLUDING COMMENTS

With the recurrent losses of lives and properties, road traffic accidents haveloomed as a serious and growing problem in urban areas of Bangladesh. The
road safety situation is very severe by international standards as well. The
global forecast has indicated that over the next 10 years developing
countries like Bangladesh will experience the alarming increase in urban
road accidents and casualties. This paper has highlighted the scale andRoad Traffic Accidents and Injuries: A Serious Safety Concern in Urban Areas of Bangladesh

663

December 2007, Dhaka, Bangladeshcharacteristics of the road safety problem in urban areas in Bangladesh. It
also discusses the strategies for improving safety. There is urgent need andscope for improving the road safety situation by implementing an effective
and coordinated safety policy and actions which require significant
improvements in the relevant sectors. Intensified efforts are needed to bringabout changes in the attitudes of road users including drivers towards safe
operations. The opportunities and need for road environmental andengineering improvements by incorporation of new approaches and methods
are particularly discussed in the paper.

REFERENCES
Hoque, M. M. Ahsan, HM, & McDonald, M., 1997, Traffic
Congestion and Safety : Some Contemporary Issues and Options in
Bangladesh, ASCE Conference on Traffic Congestion and Traffic Safety inthe 21st Century, Chicago, Illinois, USA, June 8-11, 1997.
Hoque, M. M., McDonald, M. & Hall, RD., 1998, Relevance andintroduction of road safety audit in developing countries, First
AUSTROADS International Road Safety Audit Forum, Melbourne 11-12
May 1998
Hoque, M. M., 2001, Road Safety Improvements in Developing
Countries: Priority Issues and options, Proceedings of 20th Australian Road
Research Board (ARRB) Conference.
Hoque, M.M., 2004, Editor of Booklet Understanding Road Safety,
Published by Accident Research Centre (ARC), Bangladesh University ofEngineering and Technology (BUET), Dhaka-1000, Bangladesh, July 2004
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664

New Technologies for Urban Safety of Mega Cities in Asia

Authors’ Index

AUTHORS’ INDEX
A
Ansary, Mehedi AnsaryAnam, Iftekhar
Ahmad, Monsur
Akand, Md. Shah Aziz
Anam, Iftekhar
Ahsan, Raquib
Ahmed, Syed Ishtiaq
Amin, Md. Sohel Reza
Ahmad, Rais
Ahmed, M. Zakaria
Amano, R
Abe, Mariko
Akther, M. S.
Ahmed, Wahida Bashar
Ahmed, Murshed
Anowar, Sabreena
Anjuman, TaheraB
Byun, Keun Joo
Begum, MahbubaC
Choi, Ho
Chang, Tai-Ping
D
Dhar, Ashutosh Sutra
Das, Rubel
Deng, Zhihua
Dutta, Dushmanta
E
Endo, Takahiro
Eicker, Ursula
Ebi, Takeyuki
F
Fujita, Kazuhisa
G
Grzmil, Toby
Guragain, Ramesh

79, 103,113, 191,
231, 265,
287, 529,
541, 555
91
183
243
243
265, 275
307
397
473
473
483
521
541, 555
579
591
607, 653
653

H
Hug, Mohammad Sajedul

Haque, Md. Nafiul
Hossain, Muhammad Shahadat
Horri, Toshiyuki
Henry, Michael
Hossain, Tahsin R.
Hossain, Md. Raquibul
Hsu, Kai-Lin
Huang, Hong
Hussain, Mohammad Asad
Hossain, Md. Motaher
Herath, Srikantha
Hayami, H.
Hayashi, Shogo
Hoque, Md. Mazharul
Hung, Armana Sabiha
Hanoka, Shinya
Hossain, Md. Zakir
Hassanat-E-Rabbi, Shahnewaz

127 I
Ishihara, Kenji
Imtiaz, A. B. Afifa
253 Iwanami, Mitsuyasu
311 Islam, Md. Shahabul
Ishikawa, Yuji
Izumi, Kimihiko79, 191 Islam, M. Kabirul
183, 417 Islam, Muhammad Ashikul
343
385 J
Joshi, Ranjeet
Johansen, Jorgen
409 Johan, Israt
425
483 K
Katayama, Tsuneo
Kanok-Nukulchai, Worsak
483 Khan, Aftab Alam
Kumar, Ramancharla Pradeep
Kuwano, Reiko
Kohashi, Hidetoshi
461 Kato, Yoshitaka

103

103
147
173
201
287
307
333
343, 441
357
357
367
441
483
607
607
631
653
653

11
79, 191
211, 221
375
453
453
473
643

161
275
529

1
41
147
161
173
173
201

K
Kato, Ema
Kanada, Hisashi
Konagai, Kazuo
Kato, Shinsuke
Kawasaki, Akiyuki
Khiem, M. V.
Kunda, Tribikram
Kabir, Md. Aynual
Kuwahara, Masao
L
Liu, Naian
Leopairojna, Supaporn Kaewko

211, 221
231
275
343
367
441
473
509
621

R
Roy, Himadree
Rizvi, Mohammad Salahuddin
Rahman, Syed Zillur
Reza, Samy Muhammad
Rahman, Md. Musur
Rahman, Md. Mafizur
Rahman, MA
Rahman, Md. Mizanur
Rizvi, Md. Kamrul Hasan

Murao, Osamu

S
343 Shamim, Mahfuza
631 Sadat, Mohammad Rafat
Saha, Rajan
Sutradhar, Ashutosh
61, 139, Siddiqui, Md. Ziya Ur Rahman
231, 297,
367, 461,
483,52167 Siddiquee, Md. Zahid Hasan

Miyamoto, Atsushi
Mayorca, Paola
Miyazaki, Sanae
Maniruzzaman, KM
Mahmud, S M Sohel

67
297, 461
453
573
607

M
Meguro, KimiroN
Noor, Munaz A.
Nakano, Yoshiaki
Navaratnaraj, Sathiparan
Newaz, Kazi Md. ShifunNag, Dilip
Nam, Jin-Won
Nakano, YoshiakiOOoka, Ryozo
Okubo, Takahide
P
Prathuchai, Kul
Phonekeo, Vibarad
Q
Quader, Mohammad Abdul

Shimomura, Takumi
Siddiquee, Mohammed Saiful Alam
Sarker, Maminul Haque
Schroder, Dietrich
Sasaki, Eiichi
Shah, Md. Faiz
Siddiquii, Chowdhury Kawsar
Arefin231, 287,
499
253 T
461 Tsukamoto, Yoshimichi
607 Takashima, Masasuke
Tanaka, Hidetaki
Tamima, Umma
Takeuchi, Wataru
Tanaka, Shinji343, 441 U
453 Uomoto, Taketo
Uddin, M. Moslam
Uddin, Mohammad Nazim
375 Uematsu, Kouji
435

417

91
103
231
265
357
375
573
643
643

79
103
113, 231
113
161

183, 417,
425
221
307
357
425
453
585
653

11
61
275
397
435
621

51, 231
287
357
483

W
Wenguo, Weng
Worakanchana, Kawin

321
435, 461

Y
Yasuoka, Yoshifumi
Yokota, Hiroshi
Yamaji, Toru
Yoshimura, Miho
Yasin, M.

409, 435
211, 221
211
139, 231
499

Z
Zobair, Mohammad
Zhang, Linhe