New Technologies for
Urban Safety of Mega Cities in Asia
October 18-19, 2004
Agra, India－Editor－

Junichi Susaki
ICUS, IISThe University of Tokyo, Japan

Organised By

Department of Civil Engineering,
Indian Institute of Technology Kanpur,
Kanpur, India
International Center for Urban Safety Engineering (ICUS),
Institute of Industrial Science, The University of Tokyo,
Tokyo, Japan

New Technologies for Urban Safety of Mega Cities in Asia
Taketo Uomoto
Director and Professor of ICUS, IIS, University of Tokyo

ICUS Report No 6, December 2004
Preface
Over half of the world's population is concentrated in urban areas covering just four percentof the world's surface. Mega Cities (exceeding a population of ten millions) in particular arecharacterized by a high population density and high material demands. Rapid urbanization is adistinctive feature of Asia with a tremendous rate of population growth. It is estimated that by 2015,
more than 50% of the Mega Cities are going to be in Asia. Due to rapid economic development,
there has been a phenomenal growth of high-rise buildings and other infrastructure in Mega Cities.
However, this growth of infrastructure is not adequately balanced by the appropriate measures fortheir maintenance and management and that has led to a deterioration of urban infrastructures andresulted in urban disasters in many cities. Moreover, dense concentration of population is leading
to high rate of water-related illness from lack of safe drinking water or inadequate sanitation orenvironmental problems.
The recent developments of various advanced technologies have generated scopes andmotivation to focus on devising appropriate methodologies for management and maintenance ofurban buildings, infrastructures, mitigation of urban disasters and environmental problems forsustainable development of Asian Mega Cities with adequate safety and security. As a large
percentage of population is under potential risk, safety and security of Asian Mega Cities deserve
increased attention of various concerned groups including the researchers and decision makers.
With this realization and recognition of the importance of advanced tools in urban safety,
International Center for Urban Safety Engineering (ICUS) of the Institute of Industrial Science (IIS)
and, organized a 2-day International symposium on October 18-19, 2004 on the use of advanced
technologies towards development of methodologies for safety and security of Mega Cities in
Asia. This symposium was also supported by 21st Century COE Program “Creation of New
Science and Engineering for Sustainable Urban Regeneration”, University of Tokyo.
The prime objective of the symposium is to bring together decision makers, practitioners andresearchers involved in these fields to share their expertise, knowledge and experience for tacklingthe critical issues of urban safety with advanced technologies. A network of Asian researchers andpractitioners was established for collaboration in various issues of urban safety of the Asian Mega
Cities through the First and Second International Symposiums jointly organized by otherinstitutions (Asian Institute of Technology (AIT), Thailand in 2002 and 21st Century COE Program,
University of Tokyo, Japan in 2003). It is strongly expected that this symposium would be aplatform for strengthening this network for future collaboration towards safety and security of the
Asian Mega Cities.
I would like to thank the Steering Committee, Technical Committee and the Organizing
Committee for their hard work, valuable suggestions and coordinating for the initiatives to makethis symposium a success.
I wish all the distinguished guests and participants the very best and successInternational Center for Urban Safety EngineeringOPENING ADDRESSSHIGEFUMI NISHIO
Director General of IIS, University of Tokyo, Japan
Honorable Guest Professor Mehesh Tandon, President of the IndianConcrete Institute,
Honorable Guest Professor Samjay Dhande, Director of the Indian
Institute of Technology, Kanpur
Distinguished Guests, Ladies and Gentlemen,
On behalf of the Institute of Industrial Science, University of Tokyo, I
take pleasure in extending a warm welcome to Professor Tandon, Professor
Dhande, and other distinguished guests and participants to the International
SYMPOSIUM ON "NEW TECHNOLOGIES FOR URBAN SAFETY OF
MEGA CITIES IN ASIA", being held here today.
At the outset, I would like to express my thanks to Professor M. C.
Tandon, Professor Dhande who have taken time out of their busy schedules
to be with us today, and agreeing to inaugurate the Symposium. I would
also like to thank Professor Sudhir Misra, and their team for the hard workin co-organizing this symposium with the International Center for Urban
Safety Engineering, or ‘ICUS’ of our Institute. I would also like to express
my regret for my inability to attend in person.
ICUS was created about three year and a half ago in response to a
growing need to deal with the various aspects of problems related to urban
safety comprehensively, create greater social and academic awarenesstowards these issues, and, serve as an agency to collect and disseminate
relevant information. Through this symposium, co-organized with the
School of Civil Engineering, IIT, the center makes an effort to start a muchneeded initiative towards greater collaboration between the professionals in
India and Japan, and further our understanding of different aspects ofurban safety.
The success of the symposium is evident by the overwhelming response
it has generated, and will be judged by the initiatives that result in terms of
exchange of information and ideas, sharing of resources, and generation of
joint research and other projects. I take this opportunity to assure all help
from my Institute and the University of Tokyo in this regard, and wish thesymposium all success.

1

7 CONTENTS

Opening session
MAHESH TANDON
Technical Hurdles of Implementing Infrastructure Projects..................

1

R.N. IYENGAR
Seismic Hazard in Urban India with Delhi as a Case Study ..................

9

Technical sessions
Disaster Management
TSO CHIEN PAN, B. LI, X. T. YOU AND C. L. LIM
From Ground Shocks to Air Blasts– Multiple-Hazard Protections .......

25

TAWATCHAI TINGSANCHALI
Optimal Improvement of Storm Sewer System for Inner Bangkok ......

37

MADHAV N. KULKARNI, NISHA RADHAKRISHNAN AND DEEPARAITechniques for Monitoring Deformation in Large Engineering
Structures ...............................................................................................

47

AKIYUKI KAWASAKI AND SATORU SADOHARA
Development of Slope Failure Disaster Management System in
Urban Area
-The Utilization of Existing Data Toward “E-Municipal
Government” ..........................................................................................

59

SAID A. ELKHOLY AND KIMIRO MEGURO
Numerical Modeling of Steel Structures in Fire Conditions using
Improved Applied Element Method ......................................................

69

REIKO AMANO, YOUICHI IZUSHI, HITOSHI KURIOKA, HIDEAKIKUWANA, TAKASHI TSURUDA, TAKESHI SUZUKI AND YOSHI
OGAWA
Water Screen Fire Disaster Prevention System Characteristics ofWater Screen as Partitioning Technology .............................................

79

DUSHMANTA DUTTA, M. J. ALAM AND S. HIRONAKA
Urban Flood Modeling in Lower Mekong Basin a physically based
Distributed Modeling Approach ............................................................

87

TRAN THUC AND NGUYEN HUU PHUC
Hydraulics Computations to Study Flood Control for Hanoi City .......

97

AYSHA AKTER AND ROWSHAN MAMTAZ
Sustainable Development of Water Supply, Sanitation and Waste
Management: A Challenge to Dhaka Urban Slum Dwellers in
Bangladesh. ...........................................................................................

104

DJILLALI BENOUAR
The need for an Integrated Disaster Management Strategy in North
African Mega cities: A Case Study of Algiers ......................................

114

Earthquake
KIMIRO MEGURO AND YASUNORI HADA
Application of Power Demand Changes to Evaluate Building andDwelling damages due to Earthquake ...................................................

124

HORI. M. AND OGUNI KENJI
Integrated Earthquake Simulation using Simulation and
Geographical Information System .........................................................

134

KUSALA RAJENDRAN AND C. P. RAJENDRAN
Understanding the Seismic Sources in India: Strategies for Seismic
Hazard Reduction ..................................................................................

142

SUDHIR K. JAIN AND C.V.R.MURTHY
Capacity Building in India towards Earthquake Risk Reduction –Role of IIT Kanpur in Past Two Decades ..............................................

156

JUNJI KIYONO AND KATSUMI NAGAI
Casualty occurrence Mechanism Induced by Train Accident during
an Earthquake ........................................................................................

158

PHAN QUANG MINH
Damage to Masonry Buildings in Dien Bien Phu Earthquake ..............

168

SHAILESH KUMAR AGRAWAL AND AJAY CHOURASIA
Seismic Vulnerability Analysis of Buildings in Jabalpur Urban Area.

172

PAOLA MAYORCA AND KIMIRO MEGUROAn Innovative Seismic Strengthening Method for Unreinforced
Masonry Structures using PP-Band Meshes ..........................................

186

KRISHNAMOORTHY, KIRAN KUMAR SHETTY AND RAVI KUMAR
Response of a Base Isolated Masonry Structure ....................................

194

N. H. M. KAMRUJJAMAN SERKER, PENNUNG WARNITCHAI AND
DUSHMANTA DUTTA
Urban Building Inventory from VHR Remote Sensing Imagery for
Earthquake Risk Analysis in Bangkok ..................................................

199

ROSHAN ALAYIL DIVAKARAN, PRABIR C. BASU AND AJAI S.
PISHARADY
Quantitative Approach for Seismic Retrofitting of Structures using
Push Over Analysis ................................................................................

211

THURAICHAMY GUGANESAN SUNTHARAVADIVEL, YOZOFUJINO AND PING ZHUEvaluation of Earthquake Caused Damages using Non-Linear
Dynamic Numerical Analysis ................................................................

223

YUSUKE ONO, JUNJI KIYONO AND TATSUKI TAMAI
Seismic Behavior of Urban Highway Tunnel in Vicinity of
Embankment ..........................................................................................

230

KOJI TAKEWAKA AND GOVINDA RAJ PANDEY
Seismic Behavior of Reinforced Concrete Piers deteriorated byCorrosion of Reinforcement ..................................................................

240

PENNUNG WARNITCHAI, SOMMAI PONGPORNSUP, UNNOPPRAWATWONG AND AMORN PIMANMAS
Seismic Performance of Post Tensioned Interior Flat Slab-Column
Connections ...........................................................................................

250

N. CHANDRA SEKHAR, K. B. S. SUNIL BABU AND PRADEEPKUMAR RAMANCHARLA
Equivalent Static Analysis as per 1893:2002: A Simple Software
Tool ........................................................................................................

260

Infrastructure Management
TAKETO UOMOTOIntroduction to JSCE Standard Specification for Concrete Structures

269

KEUN JOO BYUN
Recent Advances in Assessment Technology of Infrastructures in
Korea......................................................................................................

279

PRASANTA KUMAR DEY AND STEPHEN O. OGUNLANA
A Risk-Based Decision Support System for Inspection and
Maintenance of Cross-Country Petroleum Pipelines .............................

285

KIANG HWEE TAN
Impact Resistance of FRP-Concrete Sandwich Panels ..........................

295

SOMNUK TANGTERMSIRIKUL
Durability Design for Concrete Structures for Urban Safety in
Thailand. ...............................................................................................

305

TOSHINOBU YAMAGUCHI, KOJI TAKEWAKA, JUNICHIMATSUMOTO AND YOSHIKAZU AKIRAAn Experimental Study on complex deterioration of Concrete using
Ground Granulated Blast-Furnace Slag .................................................

313

S. K. MANJREKAR
Case Study of the Repair of a Major Bridge and Some Thoughts on
Repair Materials.....................................................................................

321

HISASHI KANADA Y. ISHIKAWA AND TAKETO UOMOTO
Development of New Method to inspect deteriorated Concrete using
NIR Spectroscopic Technique ...............................................................

331

M. A. ANSARY AND M. A. NOOR
Vulnerability Assessment of Existing Engineered and Non
Engineered Structures of Dhaka City using RVS and NDTTechniques .............................................................................................

341

YOSHITAKA KATO
Maintenance Management of Concrete Structures by using RepairRisk ........................................................................................................

351

K. K. BAJPAI, C. V. R. MURTY AND DURGESH C. RAI
Influence of Fiber Wrap Retrofitting on Gravity Designed RC
Beam-Column Joints under Cyclic Loading..........................................

359

TAMON UEDA
New Concept for Retrofitting Concrete Structures with
Unconventional Materials ......................................................................

369

TIJO THOMAS AND PRADEEP KUMAR RAMANCHARLA
Simulation of Plate Behavior under Non-Uniform Wind Loads ...........

379

T. R. WARSI AND ANURAG KHANDELWAL
Urban Safety and Security Issues, Constraints and Challenges
ahead-Agra .............................................................................................

389

MAHUA MUKHERJEE
Urban Safety in Asian Cities: For the city dwellers, by the citydwellers ..................................................................................................

395

Environment
VIRENDRA PATHAK AND ONKAR DIKSHIT
Per-Field Classification of Indian Urban Environment using IRS-1C
Satellite Data ..........................................................................................

405

TRAN HUNG AND YOSHIFUMI YASUOKA
Surface Climatic Impacts of Urbanization in the Ho Chi Minh City,
Vietnam: An Integrated Study with Remote Sensing and Modeling

415

T. G. SITHARAM, C. S. VISWANATHA, M. S. SUDARSHAN AND
P. S. R. NARASIMHA RAJU
Subsurface Geotechnical Characterization Map of Bangalore City
using 3-D Analyst in GIS.......................................................................

423

EKTA AMAR AND BHARAT LOHANI
Registration of Laser Scanner Point Clouds for a large and complex
Building .................................................................................................

431

YOSHIFUMI YASUOKA, YOSUKE YAMAGISHI, TAO GUO, AND
TAKAHIRO ENDO
Extraction and 3-D Visualization of trees in Urban Environment.........

441

S. K. KATIYAR, ONKAR DIKSHIT AND KRISHNA KUMAR
Ground Control for the Geometric Correction of Remotely Sensed
Imagery: Requirements and Issues in India ...........................................

447

SURENDER SINGH AND B. S. SOKHI
Internet GIS based Municipal Information System: A Case Study ofDehradun Municipal Area .....................................................................

454

RYOZO OOKA, SHINSUKE KATO, HONG HUANG AND TAKEO
TAKAHASHI
Prediction of Atmospheric Pollutant Dispersion in an Urban Area byWind Tunnel Experiment and Numerical Simulation ...........................

463

D. MOHAN
Automobile Traffic Generated Atmospheric Pollution: Need forconsideration in Urban Infrastructure Planning .....................................

469

K. VENKATESAN AND K. P. SUBRAMANIAN
Road Safety Audit – Chennai ................................................................

479

RAJIV GUPTA
2D-EA for Facility Allocation ...............................................................

488

K.W. FOONG AND H.C. CHIN
Pedestrian Speed-Flow Model on Escalators and Staircases .................

498

JAYARAM H., VINOTH M. AND RAGHURAM P.
Tele-Operated Surveillance Robot ........................................................

508

DUSHMANTA DUTTA AND TAKETO UOMOTOICUS and AIT Collaboration on Urban Safety Research ......................

516

SHARAD VIMAL OBEROI AND NARINDER KUMAR THAKUR
Safety Assessment of Existing Road in the Himalayas using
Geographic Information System and Satellite Imagery.........................

526

Gate of Hotel

Symposium Hotel

Symposium Hotel

S. Misra

Opening Ceremony1iOctober 2004, Agra, IndiaM. Tandon

R. N. Iyengar

At Banquet

Poster of ICUS and IIS

2

T. C. Pan

New Technologies for Urban Safety of Mega Cities in Asia
ii

ICUS Report 6

T. Tingsanchali

T. Thuc

C. V. R. Murthy

P. Q. Minh

P. Wanitchai

K. J. Byun

3iii

October 2004, Agra, India

At Presentation

4

K. H. Tan

S. Tangtermsirikul

M. A. Ansary

T. UedaNew Technologies for Urban Safety of Mega Cities in Asia
iv

ICUS Report 6



T. Hung

At Presentation

End of the Symposium

5v

Opening Session

TECHNICAL HURDLES OF
IMPLEMENTING INFRASTRUCTURE
PROJECTSMAHESH TANDON
Tandon Consultants Pvt Ltd, New Delhi, INDIA
ABSTRACTThe current infrastructure scenario boasts of fast-track projects, manyof which are in the process of being constructed with still others in thepipeline. While they are indicators of urban development and progress, they
are not without their attendant ills: ugly dug-up trenches, diminished roadwidths, crawling traffic, frequent bottle-necks, short-tempered commuters,
etc.
More often than not the implant of an infrastructure project in an
urban landscape is in the nature of a fire-fighting exercise facilitatingpedestrian cross-over at one intersection or removing vehicular congestionat another or providing a signal-free stretch elsewhere. Symptomatic
solutions such as these however, pose technical hurdles that include
construction technology, land acquisition, traffic diversions anddisturbances, effect on environment, to name a few.
This paper highlights the technical hurdles that challenge theimplementation of infrastructure projects.
1.0 INTRODUCTION
Construction of transportation infrastructure structures like flyovers,
viaducts, underpasses, tunnels, etc in urban situation poses many technicalhurdles. Unfortunately, infrastructure requirements are or should be
proportionate to the population residing in the area and hence more andmore problems arise because of the existence of already built-up andcongested areas where the structures have to be implemented.
2.0 DESIGN CONCEPTION AND CONSTRUCTIONTECHNOLOGYAppropriateness of design conception and construction technology
adopted for implementation of the structure is the most importantconsideration for urban transportation structures. Precast segmental
construction technology, whereby small elements can be fabricated in acentralized casting yard and conveniently transported on the existing road
network, is a popular choice, Fig 1. This also reduces site concreting with its
attendant environmental issues like dust, noise, etc. Though the spanarrangements can be fixed in advance the structure should be capable of11October18-19, Agra, India

Low Bedded Trailer
Figure 1: Transportation of Segment to Siteabsorbing minor changes in span lengths during construction. This isnecessary because of the possibility of encountering un-chartered utilities
which are discussed later in this chapter.
3.0 PROBLEMS OF LAND ACQUISITION
The central verge of the road is ‘no-man’s land’ and presents thepossibility of placing piers for long elevated viaducts without the necessityof acquisition of land or reducing the ground level carriageway, Fig 4.
However, at points of take-off from ground level, large widths of thestructure have to be accommodated, which results in a reduction of thecarriageway width at such points.
For flyovers which are generally of small length, the ground level road
becomes unusable for the whole width of the flyover.
4.0 FAST TRACK CONSTRUCTION
The importance of fast-track construction cannot be over-emphasisedfor urban transportation projects. The design conception and methodology
of construction must be geared for speed. Not only disturbance to life must
be minimized but reverting back to improved version of ‘normalcy’ must be
effected in the shortest possible time.
Detailed planning and constant monitoring by an experienced project
management team hold the key to fast track construction.
Without incentives and disincentives, fast track construction has
seldom been implemented successfully. Provisions for attractive bonus forearly completion and strong penalties for delays must form an integral part

New Technologies for Urban Safety of Mega Cities in Asia
22

ICUS Report 6of the contract document. There are some very good examples where suchprovisions were made, viz the 50-odd flyovers on Mumbai city werecompleted in record time due to the innovative tender provisions introducedby the Maharashtra State Road Development Corporation (MSRDC), whowere in charge of the implementation.
5.0 QUICK DISPUTE RESOLUTION
Good unambiguous contract documentation is the key for reducing
conflicts during implementation. However, differing interpretations andperceptions can still give rise to disputes. Also, no contract documentation
can foresee all the problems that may surface during construction. However,in such circumstances, there should be no slowing down or shutting down of
the construction activities.
When disputes do arise during project implementation, a previously
identified and agreed-to transparent mechanism for its resolution should be
activated. The decisions of this mechanism should be binding on all partiesof the dispute at least as far as the construction speed is concerned.
6.0 TRAFFIC DISTURBANCE/DIVERSION DURING
CONSTRUCTION
There must be minimal disturbance to traffic during construction, Fig
2. To achieve this objective, the diversions have to be planned carefully at
the conceptual design stage.

Figure 2: Pitampura Cantilever Bridge no disturbance to Traffic(38.5m + 55m + 38.5m)

Technical Hurdles in Implementing Infrastructure Projects
33October18-19, Agra, India

The type and sequence of construction have a significant impact on thedesign. Hence, without a complete knowledge of how traffic would move on
the arterial road during various stages of construction, the concept design
itself may be initiated in the wrong direction.

Figure 3: Construction Sequence of Substructure and Superstructure ofCurved Over Bridge, AIIMS Crossing
A good example of the planning for traffic diversions and its effect on
the design can be seen in
Figure 3.
7.0 SAFETY DURING CONSTRUCTION
In urban transportation projects, the construction has not only to caterto workmen present on location, but also passers-by and habitants of thearea. Apart from preventing physical injury to human beings who mustreceive the greatest attention, damage to existing infrastructure, especially
utilities, must be avoided.
Proper barricading, signages and diversion are part of the process of
ensuring safety during construction, given the heavy machinery andequipment that may be deployed on the project, Fig 4.

New Technologies for Urban Safety of Mega Cities in Asia
44

ICUS Report 6

Vibro-Hammer

Steel Casing

Figure 4: Safety During Construction
8.0 ENVIRONMENTAL IMPACT & AESTHETICS
How will an infrastructure project impact its environment? It is
important to analyse and assess the potential impact of urban transportation
projects on the natural, social and cultural environment of the area bothduring construction and in-service conditions.
Some of the issues can be identified as follows: Noise and dust pollution
 Replanting of trees which require to be displaced Rain water harvesting due to large built-up areas being created Landscaping to soften the visual impact
 Disposal of waste material , eg bentonite
Due to its sheer size and importance in sociological terms,
infrastructure projects loom prominently in the public consciousness.
Disregarding its harmonious integration into the natural or built
environment can have significant repercussions, the detrimental effects ofwhich are always significant.
Graceful and aesthetic bridges elicit a sense of appreciation fromlovers of natural beauty crowning majestic natural splendors. Smooth andelegant flyovers earn the unmitigated gratitude of millions of urban dwellers
enhancing quality of life in the cities.

Technical Hurdles in Implementing Infrastructure Projects
55October18-19, Agra, India

A good example of a project with a positive impact on theenvironment is shown in Fig 5. Aesthetics is a matter of good proportioning,
shape and texture of the structure and reducing the visual impact of thebulky and heavy elements, Fig 6.

Figure 5: Aerial View AIIMS-Safdarjung Crossing

Figure 6: Delhi Metro Viaduct Structural Engineer's Impression

New Technologies for Urban Safety of Mega Cities in Asia
66

ICUS Report 6

9.0 UNDERGROUND UTILITIESFigure 7: Example of Un-Chartered Utilities

Figure 8: Irregular Configuration of Piles for Straddling Across
One of the most common reasons for delays in implementation of
infrastructure projects can be attributed to the identification, removal andTechnical Hurdles in Implementing Infrastructure Projects
77October18-19, Agra, India

diversion of underground utilities that comprise as diverse items as power
cables, telephone lines, water and oil pipelines, sewage and storm waterdrains and latest inclusions like gas pipelines and optical fibre cables, Figs 7,
8.
Identification of the underground utilities poses a problem because not
only are they ‘hidden’ but frequently ‘un-chartered’, implying complete
ambiguity regarding their nature and location. Once identified, their removal
and diversion often proves more difficult and time-consuming as different
authorities responsible for them operate on un-coordinated time framesleading to great inconvenience to the public, not to mention significant cost
and time over-runs.
10.0 HARDENED FACILITIES
While protection of urban infrastructure from attacks by terrorist
activity or vandalism is difficult, it is important to introduce features thatwould discourage such action due to difficulties imposed.
Some precautions which can be taken is to avoid external prestressing,
introduce ‘integral’ bridges which can preclude bearings and thwart ingressor access to the structure except at a few designated points that can be
specifically protected.

New Technologies for Urban Safety of Mega Cities in Asia
88

ICUS Report 6

SEISMIC HAZARD IN URBAN INDIA
WITH DELHI AS A CASE STUDY
R.N. IYENGAR
Department of Civil Engineering,
Indian Institute of Science, Bangalore, INDIA
1.0 INTRODUCTION
Strong earthquakes are rare events, rarer than cyclones, windstorms
and tidal waves. Nevertheless, India has seen quite a few earthquakes in the
recent past. It is not that the frequency has suddenly increased.
Earthquakes have been known in this country from pre-historic times, moreor less in the same regions, where they are presently felt. The present,
apparent heightened awareness towards earthquake disaster mitigation in the
country is attributable to large loss of life and property suffered during the
Khillari (30th September 1993), Jabalpur (22nd May 1997) and Bhuj (26thJanuary 2001) earthquakes. Post-event analysis of the regions affected bythese earthquakes show that the pre-event seismic risk to structures was very
high, and they were already in highly vulnerable conditions. It is wellrecognized that the seismic hazard of a city or a region is a natural property
that cannot be altered. Human intervention in a habitat is possible to theextent the vulnerability of the built environment can be reduced leading todecreased risk levels and hence mitigation of a foreseen disaster.
Indian cities have grown unplanned and uncontrolled in recent years.
In 1947 the population of the country was 33 Crores, of which 14% wasurban. Presently, it is estimated that about 33-35% of the total population of
100 Crores (one billion) is concentrated in some 25-30 urban centers. Apartfrom the active migration of rural population to urban areas, it is observedthat Indian cities have a tendency to expand and capture nearby villages into
their territory. Thus, about 25% of urban population in the country lives inslums. In addition, there is always shortage in urban housing, which wasestimated at 66.4 Lakh units in 2001. Hence, we have a situation where thequality of life shows dramatic spatial variation in a city than in a village.
The same can be said about the vulnerability of constructions andinfrastructures in big cities. With reference to residential buildings; Kutcha(informal), Semi-Pucca (semi-formal) and Pucca (formal) houses in ourcities are roughly in the proportion 8:16:76, whereas this figure is 34:35:31
for rural areas. The above classification approximately corresponds to Atype, B-type and C-type buildings of the seismic code IS-1893. The 76% Ctype houses in urban areas are not necessarily built to high standards ofsafety. They are particularly constrained by limits of affordability andacceptability. Thus, it is the social and economic rather than technological,
issues that govern the safety of our cities during natural calamities. It is withthese points in the background we have to discuss seismic hazard,
vulnerability and risk to Indian cities. Success of disaster mitigation
strategies depends on how well the stakeholders are sensitized to the
Seismic Hazard in Urban India with Delhi as a Case Study
923

October18-19, Agra, India

necessity for reducing the vulnerability of their structures. Since earthquakes
are rare and unpredictable, there is always a tendency among the lessinformed persons, in the local administration, to deny the importance of risk
mapping of cities as a pro-active step in the right direction. In recent years,
it has been well recognized that national level seismic zone maps are at best
preliminary estimates. They are useful as guides but cannot be substitutes
for micro-zones of cities existing near active faults. Microzonation, whichmaps the hazard, vulnerability and risk to the built environment in a city,
targets the building owners, local administrators and elected representatives
responsible for the welfare of a ward of the size of approximately one
square kilometer. The challenge one faces here, is to scientifically computethe basic hazard on small scales of the order of 1km x 1km, with faults thatare hundreds of kilometers long at unknown depths, spread randomly in thecontributing seismo-tectonic region of about 300,000 sq. km. Municipal
engineers who like to evaluate the vulnerability or safety of existingbuildings, need to know how the ground will vibrate in future at their sites
within the city. This ground motion lasting for a few seconds is due to therelease of energy stored for centuries at the fault level, but is nonethelessstrongly influenced by the local soil conditions at the site. By superposing
the building typology descriptions on the hazard map one can construct thevulnerability map, provided the damage probability matrices or motiondamage relationships are available. Damage statistics can be converted into
financial loss estimates to create a risk map also for a city. Ultimately,
seismic risk reduction achieved by a city habitat depends on how well thethree key subjects namely engineering, earth sciences and social sciences
are made to converge by the metropolitan administration.
In this article, the focus would be on how the seismo-tectonic
knowledge of a region can be converted into a city level hazard map forengineering purposes. Delhi, the capital city of the country is taken as an
example. In a city like Delhi founded on the banks of a river, that hasbrought several million tonnes of sediments from Himalayas, surface levelground motion can vary dramatically within short distances. A case studyof mapping seismic hazard of Delhi through probabilistic seismic hazard
analysis methods is presented with some limited and qualitative results on
soil amplification.
2.0 SEISMIC HISTORY
A general review of the seismic status of Delhi, has been previously
presented by the author (Iyengar 2000). Varāha Mihira, who lived in 5th
century A.D., has mentioned northern India including Delhi and its
surroundings as the felt region of severe earthquakes. However, the first
historically reported earthquake in Delhi city was on 17th July 1720. The
MMI value of this event at Delhi (Old) has been estimated to be IX(Srivastav and Roy 1982). Even though the focus of this event has not been
identified, from historical accounts it is surmised that the source should havebeen near Delhi city. It is known that Agra was affected severely by anearthquake on 6th July 1505. Another event of high intensity felt in theAgra-Mathura region on 25th August 1803 has been described by Nazir

New Technologies for Urban Safety of Mega Cities in Asia
1024

ICUS Report 6

Akbarabadi (1740-1830) in his Urdu poem bhūcāl-nāma (UPHS 1992). This
event caused damage to Kutub Minar, one of the famous landmarks of Delhi.
Again, the source of the shock has not been identified. However, it isgratifying to note that Taj Mahal withstood this event with no recognizable
distress. In recent times an event of magnitude ML=6 occurred on
27thAugust 1960, having its epicentral tract in the Delhi-Gurgaon region. On
28th July 1994 an event of magnitude ML=4 caused minor damage to a few
old buildings. While these events have had their sources in the Indogangetic plains nearer to Delhi city, distant events originating in the
Himalayan plate boundary, such as Uttarakashi (ML=6.4, 20th October 1991)
and Chamoli (ML=6.8, 29th March 1999) earthquakes have caused
nonstructural damage in some parts of Delhi. Thus, the hazard at Delhi iscontrolled broadly by two different tectonic regimes with different
recurrence characteristics.
3.0 REGIONAL SEISMICITY
From past investigations, it is known that a strong earthquake can
induce severe ground vibrations up to distances of about 300 Km from its
epicenter. It follows, for any site one has to consider all active faults within
300 Km radius of the site. Here, with India Gate in Delhi as the center, aseismo-tectonic map (Fig. 1) has been prepared, taking information fromvarious sources (Valdiya 1976, GSI 2000, Srivastava and Roy 1982). Wellknown geological features of Himalayas such as the Main Boundary Fault(MBF) and the Main Crustal Thrust (MCT) have several tributaries also. In
the present study, all such branches have been merged with the parent fault.
In Fig.1, twenty important faults are shown along with the known 278 past
epicenters. This figure highlights Delhi’s susceptibility to earthquakes
originating either from the Himalayas or from local sources. The faults arenumbered for further reference and some of their details are presented inTable 1. The magnitude Mu given in this table refers to the estimatedmaximum magnitude a particular fault may be able to produce. This value
has been assigned based on past information, without excessive
conservatism. The hazard at any point in Delhi is a function of the seismic
activity of the region, which in turn is directly related to the individual
recurrence property of the listed twenty faults. This amounts to stating thatthe quantified regional seismicity has to be accounted by the twenty faults indiffering proportions. In the present case, this regional seismicity has to beunderstood for engineering purposes in terms of historical data, in thecontrol region around Delhi city. Here we consider the historical period tobe 1720-2001, during which there were 278 catalogued events of ML  3 inthe region. Aftershocks of large events have been omitted from this list. It is
well known that catalogues contain more number of small magnitude eventsof recent dates detected with the help of instruments. On the other hand,larger earthquakes are rare but even without instruments their occurrence
would be known from general regional history. This points to the limitationthat any regional catalogue will be complete, at different magnitude levels,with differing periods of representative history. Quantification ofcompleteness of a catalogue is essential to arrive at reliable (a, b) values in
the Gutenberg-Richter recurrence relationship. Here, an additional
Seismic Hazard in Urban India with Delhi as a Case Study
1123

October18-19, Agra, India

complication arises due to the control region being not seismicallyhomogenous. To keep the work tractable, with the limited amount of
reliable data available, the control region has been divided into two partsdenoted as the Himalayan region (HR) and the Delhi region (DR) as shownin Fig.1. The maximum likelihood method proposed by Kijko and Sellvol(1989,1992), has been used for each of the two parts, with an upper boundon the maximum magnitude, to obtain the regional (a, b) values. Thismethod can handle small errors and incompleteness in the data set. This
leads to the expected values b=0.780.04 for HR and b=0.870.04 for DR.
The recurrence relationships for the two sub-regions associated with Delhi,
are shown in figure 2.
4.0 FAULT DEAGGREGATION
A given point in the target region will be subject to ground motion
from any of the twenty faults. However, each fault has different length,orientation and seismic activity rate. To compute the ground motion due toan event on a particular fault source s one needs to know the magnitude ofthe event and the site to source distance. The magnitude of a future event on
any fault is a random variable since that fault has potential to produce anearthquake of magnitude m in the interval (m0, mu) as per its own recurrence
properties, which is not known. To circumvent this difficulty, the heuristic
principle of conservation of seismic activity is invoked. According to thisprinciple, the number of earthquakes per year with m>m0 in the region,
denoted as Nr(m0), should be equal to the sum of number of events Ns(m0)(s=1,2,…Ns) possible on the different faults. For seismic hazard analysis,
m0 can be fixed at 4.0 since events of still lower magnitudes are not ofengineering importance. However, any fault longer than the rupture length
required to cause an event with m0=4, can generate ground vibration at thesite in future. This observation leads one to recognize that Ns(m0) may betaken to be proportional to the length of the fault. This gives the weighting
factor s=Ls/Ls as an activity indicator for fault s. However this need not
be the only factor influencing Ns(m0). For example, a shorter fault may be
more active at the lower magnitude level m0, than a longer fault that is
capable of producing a higher magnitude. This property can be included if
the slip rate of various faults in the region are known. Since this is notknown, one has to proceed differently. All the past earthquakes are assigned
to the twenty faults depending on the proximity of the respective epicentersto these faults. This way another weighing factor s, which is the ratio of thepast earthquakes attributed to fault s to the total number of earthquakes in
the region is obtained. This leads to the relation
Ns(m0) =0.5(s + s) Nr(m0)(s=1,2,….20)(1)

The weight ws=0.5(s + s) assigned to each fault is given in Table 1. With
the help of the above expression, the regional recurrence is deaggregatedinto individual fault recurrence as shown in Fig. 3. Here it may bementioned that the b-value of a fault has been taken to be equal to theregional b-value.

New Technologies for Urban Safety of Mega Cities in Asia
1224

ICUS Report 6

5.0 ATTENUATION OF PGA
The peak ground acceleration (PGA) at a site depends strongly on
the magnitude of an event and the corresponding hypocentral distance. The
pattern of decay of PGA with distance is a property of the region. The
current practice is to obtain the attenuation relation by empirical methods,
based on instrumental data. Sharma (1998) has proposed one such empirical
relation, valid for mixed soft soil and rock sites in North India. However, he
has not reported the standard deviation of the error in the regression. Hence,
it is not applicable in probabilistic seismic hazard analysis (PSHA). With
this in view, it is thought appropriate here to derive a relation valid for rocksites in northern India. By definition, such sites are expected to have a shear
wave velocity of 0.76<Vs<1.5 km/s in the top layer of about 30 meters.
Available strong motion data at such sites consists of 38 samples from
Sharma’s database plus 23 samples of new data. With the help of this data,
the attenuation relation valid for rock sites in the Delhi region is obtained aslog10 ( y )  C1  C 2 M  B log10 (r  e C3M )  P(2)

C1= -1.5232, C2=0.3677, C3=0.41, B=1.0047, =0.2632,

In the above equation P=0, stands for the median or 50 percentile (PGA/g)
value and P=1, leads to the 84 percentile value of (PGA/g). A comparison
between the present equation and the one given by Sharma, for mean PGA
value, is shown in Fig. 4. The two relations are similar except for minor
differences, which are attributable to mixed soil conditions retained by
Sharma, in his database.
6.0 PROBABILISTIC SEISMIC HAZARD ANALYSIS (PSHA)

Probabilistic seismic hazard analysis has been discussed in theliterature notably by Cornell and Merz (1975), Kiureghian and Ang (1977),
Bullen and Bolt (1985) among others. Presently, international engineering
standards and manuals such as USDOE-1024, IBC-2003, USNRG-1.165
and EM-1110 of US Army Corp of Engineers, specify hazard in terms of agiven value being exceeded at a particular probability level in a time
window of one or more years. If the number of earthquakes randomly
occurring on a fault is taken to be a Poisson process, the probability of therandom variable (Y=PGA/g) exceeding the level a in the time period T at thesite can be expressed in terms of the annual rate of exceedance a as,P(Y > a) = 1- exp(-a T)(3)

The basic expression for a isNs

 a   N s (m 0 )s 1m

 P (Y  a | m , r ) p

R |M( r | m ) p M ( m ) drdmr(4)Seismic Hazard in Urban India with Delhi as a Case Study
13

23

October18-19, Agra, India

It is emphasized here that the above expression sums up all theindividual contributions of twenty faults (s=1,2,…20) to obtain the annual
probability of exceedance of PGA. As an example, for the central point(India Gate) of Delhi, the individual contribution of all the twenty faults tothe mean annual hazard is presented in Fig.5, along with the total value.
Details of the computations involved are presented elsewhere (Iyengar andGhosh 2004). Once the value of a is found at a site, the probability of rocklevel PGA exceeding a design value a in a life period of T years is given byequation (3). By repeating the above computations at various points
representing Delhi and its environs, one can construct a micro-zonation map
to any required level of detail. Here, a rectangular region of 40 Km x 30
Km, with India Gate as the central point is taken as the target region. Thisregion is divided into 1320 grid points at 1km x 1km distance apart. PSHA
incorporates all known faults, epicenters, past data and local characteristics
in a judicious manner to arrive at the site-level hazard. Here, this result isshown in Fig. 6, as (PGA/g) value, with 2% excedance probability in 50
years. This corresponds to a return period of 2500 years as suggested by theInternational Building Code IBC-2003. At the rock level, it is seen that thehazard peaks up near the local Delhi fault at the center of the city. Thiseffect is also seen from Fig.5, where the contribution of individual faults tohazard at the center point is shown. As one moves away from the center
towards the corners, the distance from the Delhi fault increases and its
contribution to the hazard decreases. The pattern of the contours in Fig.6
indicates that the hazard is strongly influenced by the southwest-northeast
trending M-D fault. The PGA value shown at the center point of Delhi is of
the order of 0.2g. This value compares with the value reported by Khattri(1992) at the probability level of 10% for a time window of 50 years. It has
to be noted that the result of Fig.6 does not include the effect of soft soil
deposits that are widely spread over Delhi. Further refinement of the microzonation map of Fig.6 is yet to be done by incorporating the effect of soft
soil deposits.
7.0 LOCAL SITE EFFECTS
It is well established that structures on rock behave differently fromthose founded on soft soils. Delhi is a typical example of a city on thebanks of a river that has left several paleo-channels over which presently
human settlements exist. Delhi has also rock outcrops in its southern
extensions, as seen from Fig.7. Besides the NNE-SSW trending ridge, theother parts of the city are overlain with alluvial sediments. These alluvial
plains are flat except for a few interruptions by clusters of sand dunes orrock outcrops. The ridge, which is an extension of the Aravali hills into
Delhi, seems to disappear below the western banks of River Yamuna northof Delhi. The land surface on the eastern side of the ridge is inclined
towards River Yamuna with an average gradient of 3.5 m/km. Geological
Survey of India (GSI 1978) summarizes the soils conditions in the
Metropolitan area in the following manner: “The depths to bed rock…..vary
from near surface in the Link Road, Pusa Road, Vijay Chowk, Daryaganj
areas to as deep as 40 to 60 m in the Patel Road, Lal Quila, Rajghat areas,

New Technologies for Urban Safety of Mega Cities in Asia
14

24

ICUS Report 6

80 to 100 m in the Aurobindo Marg- IIT area and 150 m in the Yamuna
river bed area. The bedrock topography, in general, is undulating,characterized by several humps and depressions. In the North Delhi area,
the depths to bedrock east of the ridge vary from near surface to 30 m, witha gradual easterly slope towards the river Yamuna. West of the ridge in theMall Road- Imperial Avenue sections the depths vary from near surface to
30 m and more, with an abrupt deepening to 90 m in the north to as much as
200 m in the Roshanara garden area in the south. In the Sabzi Mandi, RaniJhansi Road area the bedrock occurs at shallow depths and at more than 20
m in the Chandni Chowk Sadar Bazar-Lal Quila areas. The bedrock isoverlain mostly by clay in the North Delhi, Aurobindo Marg, and Yamuna
river bed areas with indications of sand/silt with kankar and granular zones
at several places. The overlying alluvium east of the ridge appears to bemostly sand/silt with kankar.” This is a qualitative, broad-brush picture ofsoil conditions in Delhi. Construction sites are of the size of a few ten
meters. Thus, the local ground vibration transferred to the structure depends
sensitively on the detailed vertical make up of the soil layers at the site. A
proper study of the effect of local soils on the hazard calls for extensive
investigations focusing on shear wave velocity and density profiles. Even
though in engineering projects bore hole investigations are common, shear
wave velocities are not routinely measured. Under these circumstances,what has been possible here is to estimate the transfer function of the groundat a few points. At construction sites borehole data up to 30-60 meter depth
are acquired for purposes of foundation design. The geotechnical parameters
obtained this way, can be used to estimate how the local soil modifies rocklevel PGA to the surface level PGA value. Seventeen borehole data from a
construction project were available for further study (courtesy M/s Tandon
Consultants Pvt.Ltd., New Delhi). The locations of these data are listed inTable 2 and shown in Fig.7. A typical profile of N value obtained by theStandard Penetration Test (SPT) is shown in Fig.8 to illustrate variation ofengineering properties of soils with depth. The N value is widely used as aproxy for shear wave velocity through empirical correlations. One such
relation proposed by Turnbull (2001) based on Australian and Japanese
information is Vs=3.9.N + 182.9 m/s with a standard error of 70 m/s. In theabsence of measured Vs values, they have been estimated from reported N
values using the above equation. By repeating this exercise for all theseventeen stations, a picture of how Vs varies with depth can be obtained.
The regression equation Vs=173 D0.2 is found to be the average variation of
Vs with depth D in meters (Iyengar and Ghosh 2004). Analyticalrepresentation of Vs has practical advantages when a large region overlain
with alluvial soils has to be studied. In such a case, the rock level motion
propagates vertically through the soil layers, as in a one-dimensional
medium, to arrive at the surface in a modified fashion. This modification,
incorporating nonlinear effects and layering properties can be carried out
using the standard software SHAKE-91. Here, using this software, surface
amplification function for unit amplitude Sinusoidal motion at the rock levelis obtained for some stations and presented in Fig.9. The amplification will
be a maximum corresponding to the natural frequency of the soil deposit. In
Table 2, the first natural frequency of the local ground is listed along withsome layering details. In the same table the engineering classification of the
Seismic Hazard in Urban India with Delhi as a Case Study
15

23

October18-19, Agra, India

sites as per international practice, using the average Vs value in the top 30
meters of the soil is also presented. Sites, where rock is not too deep, would
correspond to site class B requiring no correction. This is the case for site
no.3 and site no.5 with high natural frequency. At such places, the seismic
hazard curve of Fig.6 can be directly used. For other sites, suitablecorrection for the PGA value would be necessary. The frequency response
functions at C- and D-type sites (Fig.9) indicate that seismic waves, near thesite resonant frequencies, are susceptible for amplification by as much as
1.5–2.5. Thus, notwithstanding the low PGA values at the rock level,surface acceleration values can be of the order of 0.3g and more in theTrans-Yamuna region. It has to be noted that Fig.9, refers to Sinusoidal
motion at the rock level. In practice, one needs the surface level acceleration
spectrum for real earthquake motion at the rock level. This calls for, moredetailed work yet to be undertaken. Engineering properties of soil deposits
can vary widely within short distances, particularly near riverbanks. Thus, itwill be appropriate to compute surface level design basis accelerations fromrock level values shown Fig.6, depending on the V30 value at the site.
Amplification factors given by codes such as IBC-2003 can be used until
results specific to Delhi region are obtained.
8.0 SUMMARY AND CONCLUSION
A planned natural disaster reduction strategy has to be built into thelarger policy frame- work of sustainable development. The vulnerability ofIndia’s urban areas has been dramatically demonstrated by recent
earthquakes; which did not originate in the more active Himalayan plateboundary. The looming risk to cities such as Delhi, Agra, Chandigarh,Gauhati and others can be perceived in the backdrop of severe earthquakes
originating either in the Himalayan zone or in the Indo-Gangetic plains. As
the cities expand, the potential for earthquake loss also increases.
Repeatedly, India has had earthquakes turning into disasters without
warning. While the loss in financial terms is a function of the state ofdevelopment, initial investment and cost of living indices, the vulnerabilityof a city is dependent on the social and economic condition of the
population. It is prudent to plan, develop and protect our vulnerable cities
from possible future earthquake destruction. It is in this context, seismic
micro-zonation of cities assumes great importance. If carried out properly,
it is an excellent scientific tool for engineers and planners for involving all
stakeholders in a city in land use planning and earthquake resistantconstruction practices. As an example, results are presented here in theform of a seismic hazard contour map covering Delhi city and its environs
for an extent of 1200 sq. km on a grid of 1 sq. km. Engineers can use thismap directly for rock sites and B-class soil sites in Delhi. For soft soil sites,
amplification factors given in codes such as IBC-2003 can be used, till
improved Vs values become available for Delhi. The present result should
form a sound basis for future extensions to cover local soil effects,liquefaction susceptibility, and vulnerability analysis of buildings. It is
hoped a national level effort will be forthcoming to map city level seismic
hazard, followed by vulnerability analysis and risk estimation, as a step
towards making our cities safer.

New Technologies for Urban Safety of Mega Cities in Asia
16

24

ICUS Report 6

REFERENCES
1. Bullen, K.E. and Bolt, B.A., (1985) An introduction to the theory ofseismology. 4th edition. Cambridge University Press. Cambridge.
2. Cornell, C.A. and Merz, H.A., (1975),’ Seismic risk analysis of Boston’, J.
of Struct. Div. ASCE, 101, ST10, pp. 2027-2043.
3. GSI, (2000), Seismo-tectonic Atlas of India and its Environs, Geological
Survey of India, Calcutta, India.
4. Der Kiureghian, A. and Ang, A. H.-S., (1977), ‘A fault rupture model forseismic risk analysis’, Bull. Seism. Soc. Am., 67, 4, pp. 1173-1194.
5. DOE Std-1020 (2002), ‘Natural phenomena hazards design andevaluation criteria for department of energy facilities’, U.S.
Department of the Energy, Washington,D.C. U.S.A.
6. EM 1110-2-6050, (1999), ‘Response Spectra and Seismic Analysis forConcrete hydraulic Structures, Engineering Manual’, US Army
Corps of Engineers, Washington.
7. GSI, (1978) ‘Urban Geology of Delhi’ Miscellaneous Publications, No.42,
Govt. of India.
8. Iyengar, R. N., (2000), ‘Seismic Status of Delhi Megacity’, Current
Science., 78, 5, pp. 568-574.
9. Iyengar, R.N., and Ghosh, S., (2004) ‘Microzonation of Earthquake
Hazard in Greater Delhi Area’ to appear in Current Science,
Bangalore.
10. IMD (2002), India Meteorology Dept. ‘Important earthquakes from the
IMD Catalogue occurred in the region bounded by 25.5o- 31.5 oN
and 74.5 o-80.5 oE’, personal communication.
11. Khattri, K.N., (1992), ‘Seismic hazard in Indian region’, Current Sc., 62,1, pp. 109-116,
12. Kijko, A., and Sellevoll, (1989), ‘Estimation of Seismic Hazard
Parameters from Incomplete Data Files. Part I: Utilization of extreme
and complete catalogues with different threshold Magnitudes’, Bull.
Seism. Soc. Am., 79, pp. 645-654.
13. Kijko, A., and Sellevoll, M. A., (1992), ‘Estimation of Earthquake
Hazard Parameters from Incomplete Data Files. Part II:
Incorporation of Magnitude Heterogeneity’, Bull. Seism. Soc. Am.,82, pp. 120-134.
14. Sharma, M.L., (1998), ‘Attenuation relationship for estimation of peakground acceleration using data from strong-motion arrays in India’,
Bull. Seism. Soc. Am., 88, 4. pp. 1063-1069.
15. Srivastava, V.K. and Roy, A.K., (1982), ‘Seismotectonics and seismic
risk study in and around Delhi Region’, Proceedings IV Congress
International Association of Engineering Geology. VIII, pp. 77-82,
New Delhi.
16. Turnbull M.L. (2001) ‘Seismic Hazard Assessment and Microzonationof Bundaberg’. Masters Thesis, Central Queensland Univ. Australia.
17. UPHS:Uttar Pradesh Hindi Sansthan (1992) Nazir Granthavali,Collection of Poems of Nazir Akbarabadi.
18. Valdiya, K.S., (1976), ‘Himalayan transverse faults and folds and theirparallelism with subsurface structures of north Indian plains’,
Tectonophysics, 32, pp. 353-386.
Seismic Hazard in Urban India with Delhi as a Case Study
17

23

October18-19, Agra, India

19.USNRG(1997): Regulatory Guide 1.165, ‘Identification andcharacterization of seismic sources and determination of SSE groundmotion’, pp. 1-45.
Table 1: Fault Characteristics
No.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

Fault Name

Mu

LengthKm.

Delhi Region
Great boundary fault
7
320
(GBF)
Mahendraghar7300
Dehradhun(M-D)
Moradabad
6.5
165
Chahapoli
5.5
215
Sabi Fracture
5.5
195
Near Mathura
5
84
Parallel fault to no. 6 5.5
115
Fault left of Alwar
5130
Fault near Alwar
555
Fault near Jaipur
5
117
Mathura
6
100
Sohna
6
105
Delhi
4.5
7
Himalayan Region
Main Central Thrust
8
350
(MCT)
North Almora thrust
6.9
280
(NAT)
Main Boundary Thrust
8
450
(MBT)
Alaknanda
5.5
51
Ropar
5
35
Near Ramgarh
537South Almora Thrust
6.5
130
(SAT)

ws

M100

0.14625.18

0.26575.47

0.07900.08720.0796
0.03710.04900.05470.02600.04970.04320.07190.0106

4.87
4.81
4.78
4.40
4.59
4.53
4.27
4.50
4.56
4.80
3.92

0.58476.87

0.13156.00

0.16476.22

0.04540.01440.0149

5.15
4.61
4.62

0.0444

5.43

New Technologies for Urban Safety of Mega Cities in Asia
18

24

ICUS Report 6

Table 2: Soil Site Location and Classification (Ref. Figure 6)

Site
no.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

Location
Sewanagar
Shahjahan Road
Boat Club
N.D. Rly.Stn.
Chawri Bazar
ISBT
Rohini
Punjabi Bagh
Kirti Nagar
Rama RoadPatel Road Jn.
Naraina RoadPatel Road Jn.
Patel Ngr.
Karol Bagh
Palika Place
Connaught
Place
Mandi House
Tilak Bridge

20.9,20.0
21.0,18.0
20.1,17.5
19.5,14.2
20.6,13.5
20.9,10.6
09.3,27.7
10.3,21.0
12.5,19.2
13.0,19.0

No.
oflayers
above
rock
10
8
4
11
4
8
24
18
19
18

13.9,18.5

11

16

2.88

834

C

14.8,18.0
17.0,17.5
19.2,17.2
20.0,16.5

9
18
16
12

14
27
24
18

2.74
1.88
2.13
2.38

910
420
524
748

B
C
C
C

21.0,15.5
22.8,16.2

11
11

40
40

1.88
1.75

339
257

D
D

Grid
coordinate
s in km.

Rock
depth
.m

Natural
Freq.
hz

Vs
m/s

55
32
12
30
09
30
200
100
40
27

1.00
1.63
5.38
1.75
6.00
2.00
0.50
0.75
1.63
2.00

235
270
1009
279
1130
317
269
271
318
296

Site
Class
as per
IBC2000
D
D
B
D
B
D
D
D
D
D

30

Figure 1: Seismo-tectonic map of Delhi Region

Seismic Hazard in Urban India with Delhi as a Case Study
19

23

October18-19, Agra, India

Figure 2: Regional Magnitude-Frequency Relationship

Figure 3: Deaggregation of regional hazard in terms of fault recurrence

New Technologies for Urban Safety of Mega Cities in Asia
20

24

ICUS Report 6

Figure 4: Attenuation of PGA in Northern India

Figure 5: Hazard Deaggregation at India Gate due to Individual Faults

Seismic Hazard in Urban India with Delhi as a Case Study
21

23

October18-19, Agra, India

Figure 6: Microzonation of hazard at rock level. Contours of mean
horizontal PGA( g) with 2% probability of exceedance in 50 years.

Figure 7: Rock Outcrops in Delhi City

New Technologies for Urban Safety of Mega Cities in Asia
22

24

ICUS Report 6

Figure 8: Bore-log at Palika Place.

Seismic Hazard in Urban India with Delhi as a Case Study
23

23

October18-19, Agra, India

(a)

(b)

(c)
Figure 9(a,b,c): Frequency Response Functions at the seventeen sites ofTable 2.

New Technologies for Urban Safety of Mega Cities in Asia
24

24

Technical Sessions

FROM GROUND SHOCKS TO AIR BLASTS– MULTIPLE-HAZARD PROTECTIONS
T. C. PAN, B. LI, X. T. YOU AND C. L. LIM
Protective Technology Research Centre, School of Civil and Environmental
Engineering, Nanyang Technological University, Singapore
TCPan@pmail.ntu.edu.sg
ABSTRACT
Singapore is an island city-state, located off the southern tip of Malay
Peninsula. It has a land area of around 700 sq km and a population of
about 3.5 millions of residents. Although small in size, the country’s grossdomestic product per capita was about US$22,500 in 2003, among thehighest in Asia. Most people live in high-rise residential buildings due to theland shortage. Being a metropolis with highly active trades and commerce,
Singapore has also seen in recent years many modern high-rise commercial
buildings constructed in her central business district.
This paper looks into the protective technologies for these modern
high-rise residential and commercial buildings against multiple hazards.
The hazards discussed here include both natural and man-made ones. They
are the effects resulting from the long-distance major Sumatra earthquakes,
ground shocks induced by underground explosions, and blast loading fromterrorist bombings. The consequences from any extreme event of themultiple hazards could be devastating to the society at large due to the highconcentration of population as well as the high-value commercial andfinancial activities housed in these modern high-rise building structures.
This paper summarizes the experiences that have been gained in Singapore
dealing with protection requirements against the multiple hazards.
1.0 INTRODUCTION
The most recent incident of terrorist car bombing occurred on
Thursday, September 9, 2004, targeting the Australian Embassy in Jakarta,
Indonesia. Many innocent people lost their lives in the tragic incident. In
Singapore, the government has cautioned the general public that a terrorist
attack against Singapore’s interests remains a possibility. While both thesecurity personnel and the general public have remained vigilant against any
possible terrorist attacks in Singapore, the engineering community has beencollectively looking into measures that may mitigate the effects of a terrorist
attack on a major building and/or infrastructure. It has thus become clearthat the adverse and fatal results of terrorism, which have become
increasingly higher, should be reviewed at the same time whenever any
additional measure to mitigate the risk of natural hazards is to be introduced.
This should form the common first step towards a platform of integrated
engineering methodologies to protect national interests against multiple
hazards. This paper attempts to summarize the experiences that have been

125

October 2004, Agra, Indiagained in Singapore which deals with mitigating the effects of both naturaland man-made hazards.
Located within the stable Sunda plate with mild winds, Singapore isbelieved to be in an aseismic area. It is about 350 km away from an active
earthquake belt, comprising the Great Sumatra Fault and the subduction
zone of Sunda Trench. Singapore has never experienced any earthquake
damage, and hence buildings are generally not designed against thehorizontal earthquake loadings. However, tremors caused by distant
Sumatra earthquakes have been felt in Singapore for many years. The
seismic response of typical Singapore buildings to the maximum credible
earthquakes from Sumatra will be discussed.
As part of the national effort to intensify the land use of the landscarce country, Singapore has explored the possibility of using undergroundfacilities for various purposes. One of initiatives is to move the surface
ammunition storages underground, which will reduce the precious landsurrounding the surface storages that have been sterilized for safety reasons.
As a result, the dynamic response of building structures to ground shocks
that may result from underground explosions has been investigated. The
results will be discussed in terms of the dynamic failure of RC buildings
subjected to ground shocks, which in turn affects the minimum radial
distance within which no residential buildings should be erected.
Recent terrorist bomb attacks around the world have demonstrated theferocity, cruelty and unpredictability of the hazards posed by terrorism.
Instead of trying to predict the next terror attack, it appears to be more
important to protect critical assets like waterworks, seaports, airports, majorbuildings, etc. The transient dynamic response of a high-rise commercial
building to a postulated external explosion load resulting from terrorist
bombing will be discussed.
2.0 SEISMOTECTONICS OF SUMATRA AND THE MCE EVENT
Sumatra is located adjacent to the Sunda trench, Figure 1, where theIndian-Australian plate subducts beneath the Eurasian plate at a rate of 67 ±7 mm per year towards N11°E ± 4° (Tregoning et al, 1994). The islands ofSumatra and Java lie on the over-riding plate, one hundred some kilometresfrom the trench. Convergence is nearly orthogonal to the trench axis nearJava, but it is highly oblique near Sumatra, where the strain is strongly
partitioned between the dip slip on the subduction zone interface and theright-lateral slip on the Sumatran fault along the western coast of the island.
Large earthquakes have thus been generated in the region. The largest
subduction earthquake that has occurred in the Sunda trench is the great
1833 event with an estimated Mw between 8.8 and 9.2 (Zachariasen et al,1999). The earthquake, with an average Mw of 9.0 with an epicentral
distance of 723 km, is thus selected for this study to be the maximum
credible earthquake (MCE) that the Sumatra subduction zone is capable ofgenerating (Megawati and Pan, 2002). The larger of the two horizontal

2

New Technologies for Urban Safety of Mega Cities in Asia
26

ICUS Report 6components of the synthetic MCE ground motions is used in the
convolution process to obtain the surface accelerations at a soft soil site.
g

12oN

,

,

10oN

8oN

Eurasian
Plate

6oN

4oN

Kuala
Lumpur

500 km2oN

Singapore

0oSumatran
Fault

52 mm/yr(N10°E)o

2 S

57 mm/yr

4oS

6oS

IndianAustralian

8oS

67 mm/yr(N17°E)
Sunda Trench

10oS

12oS o
93 E

95oE

97oE

99oE

101oE

103oE

105oE

107oE

109oE

Figure 1: Seismotectonics of Sumatra region
3.0 EFFECTS OF LONG-DISTANCE MAJOR EARTHQUAKESOne of the tallest buildings in Singapore that has been instrumented tomonitor its seismic response has recorded 21 sets of seismic response data
during the last decade. A detailed three dimensional finite element (FE)model of the building is constructed to simulate the seismic structural
response. The correlation analyses of the recorded and the simulated seismic
responses of the instrumented tall building to the major Bengkulu, Sumatra
earthquake (Ms=8.0) which happened on June 4, 2000, Figure 2, (Pan et al.
2001a) are presented in this paper.
A three dimensional mathematical model was constructed fornumerical analyses. The FE model shown in Figure 3 contains 3,185 frame
elements and 2,223 shell elements, and has 20,808 degrees of freedom.
Besides the main structural elements, major openings, secondary openings
and internal thin walls within the central core have all been considered inthis model. The basement acceleration records of the earthquake occurred in

From Ground Shocks to Air Blasts – Multiple-Hazard Protections
27

3

October 2004, Agra, Indiayear 2000 at Bengkulu, 685 km away from Singapore are used as the input
motions.

Figure 2: Epicentres of recorded earthquakes

Figure 3: Floor plan and perspective view of the FE model
The simulated results and the recorded roof motions are shown in
Figures 4a and 4b. The responses consist of mainly the first two naturalmodes in both directions and the rigid-body motions. The smaller spikes inthe spectra of the simulated results at the first translational mode frequency
in each direction, 0.19 Hz and 0.21 Hz for the x and y directions
respectively, suggest that the FE model may be stiffer than the actual
structure. This is also indicated by the measured fundamental frequencies
which are higher than the simulated ones. The smaller spikes in the spectra
may also be due to the consistently smaller magnitude of the simulated time
histories when compared with the recorded ones. However, for this largest
event recorded, the simulated and the recorded time histories match very
well in both the displacement and velocity responses, except in the later

4

New Technologies for Urban Safety of Mega Cities in Asia
28

ICUS Report 6portion of the responses in the y direction, where the simulated results are
smaller compared with the field records. Such phenomena were also
observed in some other events, though sometimes in the other direction.
They may have been caused by the sudden wind blows. The maximum
values of the simulated roof displacements are 16 mm and 31 mm in the x
and y directions, and those of the recorded roof displacements are 21 mm
and 33 mm.

Figure 4(a):Bengkulu event (2000.06.04): comparison of time histories atroof level in the x direction

Figure 4(b): Bengkulu event (2000.06.04): comparison of time histories atroof level in the y direction
4.0 EFFECTS OF EXPLOSION-INDUCED GROUND SHOCKS
Explosion-induced ground motions (EIGMs) or ground shocks could
be one of the possible damaging ground motions to be faced in the lifetimeof a structure owing to accidental or intentional explosions. However, sinceground motions of earthquakes and EIGMs are inherently different, direct
application of earthquake engineering principles to ground shock cases may
be questionable. By subjecting a lightly-reinforced RC frame to a simulated

From Ground Shocks to Air Blasts – Multiple-Hazard Protections
29

5

October 2004, Agra, India
EIGM, the suitability of current earthquake design philosophies and damage
assessment techniques for EIGMs is investigated in this section.
EIGM characteristics can be segmented into two parts: the major
shock duration (Phase I) and the ensuing duration (Phase II). Dhakal andPan (2003) showed that the high frequency nature of an EIGM led to a large
shear force with small deformation during Phase I followed by significant
deformation in Phase II. Other studies have shown that the EIGM produces
significant local damages owing to the high frequency content of EIGMs(Ma et al, 2002). In this paper, impulse per unit mass of a ground motion isused as a gauge of the damaging potential of the ground input.
4.1 Member and joint strengths
Member strength includes flexural and shear strengths, respectively.
While the predictive flexural strength equation stated in (Park and Pauley,1974) has been widely accepted, there is less confidence on the existing
shear strength predictive equations (ASCE-ACI, 1973, Karim, 1999,
Priestley et al, 1994). Shear strength has been regarded to comprisecontributions from concrete and steel reinforcement. With variations of thesteel contribution, these predictive equations state a similar concrete
contribution (Karim, 1999, Priestley et al, 1994). For the small deformationin Phase I, the contribution of the longitudinal reinforcement to the member
shear strength may not be significant. Thus, the shear strength of members
during Phase I would mainly be contributed by the concrete strength.
Observations of the buildings damaged during the strong Chilean
earthquakes of the 1960’s showed damage in the beam-column joints (i.e.
joint panels). Joints act to transfer forces between beams and columns, andso their state reflects the extent of the load transfer mechanism. Joint
performance has been observed to be dependent on joint shear strength(Paulay and Priestley 1978). When the joint shear strength is exceeded,
member strengths will be compromised. For a non-seismically designed
joint, joint cracking and joint failure were observed at a 0.5% and 3% interstorey drift ratios, respectively (Pan et al 2001b, Li et al 2003).
4.2 Post-elastic response and damage assessment
Hysteretic models attempt to describe the post-elastic behaviour of RC
members in terms of hysteretic energy dissipated. The advantage of using
hysteretic model of members over material model is its lower computational
effort. Park and Ang (1985) proposed a three-parameter post-elastic model
where the post-elastic behaviour of members is described by stiffness
degradation, strength deterioration and pinching parameter. In earthquake
response analysis, damage assessment techniques provide qualitative
information of structural performance under earthquake actions. Damage
assessment techniques may be classified as strength-based, response-basedor the hybrid of the two. Of the many damage assessment techniques, thehybrid damage assessment technique by Park and Ang (1985) is widely used.

6

New Technologies for Urban Safety of Mega Cities in Asia
30

ICUS Report 6

The damage levels were categorized as moderate, severe and partial or totalcollapse.
4.3 Response to a simulated EIGM
A non-seismically designed 6-storey RC frame was subjected to asimulated EIGM. The RC frame and the details are shown in Figure 5. The
simulated EIGM is similar to that used in (Ma et al, 2002) for the horizontal
ground motion at a distance from the explosion source. The simulated
EIGM has a peak ground acceleration (PGA) of 124 g and a predominantfrequency of about 200 Hz, Figure 6.
The IDARC software (Valles et al, 1996) with Park and Ang’s threeparameter hysteretic model and damage assessment procedure was used foranalysis. For a qualitative understanding of the generic damage assessment
techniques, local mode responses described in Ma et al (2002) were notmodelled, while 3% inter-storey drift ratio was used as the joint failure
criterion. The shear failure occurs when the nominal shear stress exceeds theshear strength predicted in Priestley et al (1994).
The Phase I responses of different storey levels (ST) are: themaximum roof displacement 12 mm; the peak inter-storey drift ratio 0.29%
reached at ST2, and the maximum storey acceleration 1.36 g at ST2. The
largest nominal shear stress occurred at the base of interior column, which
was below shear strength. The damage level was moderate according toPark and Ang’s model. The Phase II response exhibited a much larger
deformation. The largest roof displacement was 230 mm, and ST6 had thelargest inter-storey drift ratio of 3.2% (i.e. joint failure). The maximum
nominal shear stress occurred at the base of interior column without shear
failure. For this column, there was flexural yielding. However, the damagelevel was identified as moderate. Therefore, such a damage level does notreflect the actual damage associated with the joint failure.
4.4 Failure analysis
To understand the effects of the duration and the input impulse of
EIGMs, duration multipliers (DM) and amplitude multipliers (AM) wereapplied on the above EIGM. The main parameters investigated are thepredominant frequency and the amount of energy. Following this procedure,
the response analysis and damage assessment of the 6-storey RC frame
subjected to a family of scaled EIGMs were performed. Both shear failureand joint failure were investigated for the first storey interior column where
the maximum shear stress occurred.
Combinations of DM and AM can lead to joint and/or failure in Phase
I or Phase II. The damage level for the first storey column is presented in
Figure 7. One bold line shows the boundary between the moderate and thesevere damage levels for Phase I, Severe (I). The other bold line shows theboundary between the moderate and the severe damage levels for Phase II,
Severe (II). Iso-impulse lines are shown as dotted lines in the background.

From Ground Shocks to Air Blasts – Multiple-Hazard Protections
31

7

October 2004, Agra, India


2Y25

3Y25

3Y25

Roof
250

500
2Y25

250
3Y18

500

3Y18

ST4
ST3

3Y13 3Y13

ST2

250

250

350
ST 1 to ST 4
Exterior Columns

6@
3500

ST5

ST 1 to ST 4
Interior Columns

All Beam Sections

ST6

250

2 @ 6000

ST 5 to ST 6
All Columns

Concrete strength = 30 MPa;
Concrete cover = 35 mm
Concrete Young’s Modulus, Ec = 26 GPa; Concrete Ultimate Strain, u = 0.002
Steel Yield Strength Y=410 MPa, R=250 MPa
Beam Links: 2R10-200; Column Links: R10-150
Reinforcement Young’s Modulus, Es = 200 GPa
3Superimposed Dead Load = 2 kPa
RC Unit Weight = 24 kN/m ;

Figure 5: RC frame elevation and details

Acceleration (g)

150
100
50
0
-50
-100
-150
0.00

0.05

0.10

0.15

0.20

Time (s)0.25

Figure 6: Horizontal acceleration time history of a simulated EIGM

Severe(II)Severe(I)Moderate

Figure 7: Zones of failure patterns for different response phases
The figure shows that the iso-impulse line of 1xE produced moderate
damage in both Phases I and II. A scaled EIGM with a DM=1 and AM=2
produced a moderate damage level. Therefore, it can be seen that thedamage level as computed does not reflect adequately the shear failure andjoint failure caused by this scaled EIGM.

8

New Technologies for Urban Safety of Mega Cities in Asia
32

ICUS Report 6


5.0 EFFECTS OF EXTERNAL BLAST LOADING
Effects of an external explosion on a high-rise commercial RC
building resulting from a vehicle bomb at the ground level near the building
are investigated in this section. The standoff distance is qualitatively
classified as long or short. The high-rise commercial building selected forthe study is a 30-storey RC structure with frames and a shear wall core. The
building structural system consists of one storey of basement, 9 storeys of
shopping centres cum car park, one mechanical floor and 20 storeys ofoffice space, Figure 8. It is about 146.5 m high, and the typical floor planfrom the 10th storey upwards is 29 m x 44 m. Some beams and all floorslabs are post-tensioned RC members

.

Figure 8: FEM model of the buildingFigure 9: Deformation and stress distributions of the long standoff caseFigure 10: Deformation and stress distributions of the short standoff case
5.1 Blast load and FEM modelling
The parameters defining the blast loading characteristics are the peakpressure and loading duration, which can be determined using ConWep(Hyder, 1991). The distribution of the blast loading is non-uniform along
the building height and varies with the explosive weight and the standoff
distance. A typical plane frame of the building was analyzed. 2D solid

From Ground Shocks to Air Blasts – Multiple-Hazard Protections
33

9

October 2004, Agra, Indiacontinuum element with 4 nodes was used to model the concrete, and rebar
element was merged with the solid concrete element (ABAQUS, 2001). The
cap plasticity model was used to represent the concrete behaviour underblast load, while the elasto-plastic model was used for rebars. The dead andthe live load were first applied prior to the dynamic analysis of building
response to surface blast load.
5.2 Blast response evaluations
5.2.1 Long standoff case
The building deformation at a representative time step of the longstandoff distance case is shown in Figure 9. The lateral displacement of theblast-loaded bottom column reaches its peak at 13.4 ms. Plastic deformation
was mainly concentrated at the bottom column and the beams of the second
and the third storeys. Most severe damage appeared in the column around13 ms and in the beam around 16 ms. The beam deformation was focused atits ends where local damages occurred. Shear wall played an important rolein the global response and exhibited a lateral vibration beginning around 30
ms resulting from the force transferred from the beams. The lateral vibration
propagated upwards and reached the roof level around 200 ms.
The maximum tensile and crushing stress of concrete are assumed tobe 1.7 MPa and 25 MPa, respectively. The cracks would first occur in theshear wall and propagate towards the upper part of the building. At 3 ms,
crushing of concrete first occurred at one corner of the fixed-end column
and at the left ends of the second and the third storey beams. As thecompressive wave propagated to the other end of the beams, the second
storey beam was almost completely crushed. Crushing of concrete in theshear wall was confined to its connection with the second storey beam.
The local damage index based on curvature is used to evaluate theflexural performance of structural elements under blast load. The second
and the third storey beams were nearly in complete failure. Sever damage
appeared in columns on the first and the second storeys and in the beams at
the fourth and the fifth storeys.
5.2.2 Short standoff case
The building deformation at a representative time step of the shortstandoff distance case is shown in Figure 10. The lateral displacement
reaches its peak value at 13.3 ms. The dynamic deformation was localized at
the blast-loaded columns between the first and the third storeys. The beams
connected with these columns might thus be damaged. Large residual
deformations were observed for the blast-loaded columns and the beams
connected to them. Compared with the long standoff case, the global
response of the short standoff case hardly existed.
Extensive cracks first occurred in the blast-loaded bottom column.
The cracks propagated sideways via the shear wall to the bottom column on
the other side of the building as well as upwards in the wall. At 300 ms, the10

New Technologies for Urban Safety of Mega Cities in Asia
34

ICUS Report 6

crack reached the roof. In addition, cracks also appeared in the transfer
girders located at the tenth storey as a large tensile stress propagatedthrough them. Compared with the long standoff case, the cracks in theconcrete columns in the short standoff case were more severe, while those in
the shear wall were less severe. At 1.5 ms, concrete crushing first appearedat the right corner of the lower end of the bottom column. The crushing zone
developed towards the central zone of the column. In addition, the concreteat the compressive zone of the second and the third storey beams wasseverely damaged.
Figure 10 shows that partial collapse or moderate damage may exist in
the columns on the first and the second storeys. The beams at the second
and the third storeys were destroyed completely. Compared with the longstandoff case, damage in the short standoff case was more localized.
6.0 CONCLUSIONSIn summary, in protecting the building structures and infrastructural
systems in Singapore, there is a need to investigate systematically theeffects of multiple hazards which may include both natural and man-madeevents. The multiple hazards that have been investigated so far comprising
the effects of long-distance major Sumatra earthquakes, explosion induced
ground shocks, and blast-induced overpressures. The dynamic response of
the non-seismically designed building structures in Singapore to these
postulated multiple hazards has shown a variety of different characteristics.
This will pose a challenge to the engineering community who must strike abalance between safety and economy in designing and constructing abuilding structure to resist the multiple hazards which may result from bothnatural and man-made events. The consequences from any extreme event of
the multiple hazards could be devastating to the society at large due to thehigh concentration of population as well as the high-value commercial andfinancial activities housed in these modern high-rise building structures.
However, it is important to realize that the dynamic effects of these events
have drastically different loading characteristics as well as frequency ofoccurrence.
REFERENCESABAQUS, 2001. Standard User’s Manual, Version 6.2, HKS, Inc.
ASCE-ACI Joint Task Committee 426, 1973. Shear Strength of Reinforced
Concrete Members. Journal of Structural Engineering, ASCE, Vol. 99,
No. 6, pp. 1091-1187.
Dhakal, R. P., and Pan, T.-C., 2003. Response Characteristics of Structures
Subjected to Blasting Induced Ground Motions. Journal of Impact
Engineering, Vol. 28, No. 8, pp. 813–828.
Hyder, D. W., 1991. ConWep: conventional weapons effects. USAEWES /SS-R.
Karim, S. R., 1999. Shear Strength Prediction for Concrete Members.
Journal of Structural Engineering, ASCE, Vol. 125, No. 3, pp. 301- 308
Li, B., Wu, Y. M., and Pan, T.-C., 2003. Seismic Behavior of Non-

From Ground Shocks to Air Blasts – Multiple-Hazard Protections
35

11

October 2004, Agra, Indiaseismically Detailed Interior Beam-Wide Column Joints for Seismic
Performance Part I: Experimental Results and Observed Behavior. ACIStructural Journal, Vol. 31, No. 8, pp. 1501–1523.
Ma, G., Hao, H., Lu, Y., and Zhou, Y. X., 2002. Distributed Structural
Damage Generated by High-Frequency Ground Motions. Journal of
Structural Engineering, ASCE, Vol. 128, No. 3, pp. 390–399.
Megawati, K. and Pan, T.-C., 2002. Prediction of the maximum credible
ground motion in Singapore due to a great Sumatran subduction
earthquake: the worst-case scenario. J. Earthquake Engrg. Struct. Dyn,
31, 1501-1523
Pan, T.-C., Dhakal, R. P., and Irawan, P., 2001a. Dynamic and PseudoDynamic tests of Lightly Reinforced Concrete Beam-Column SubAssemblies. Technical Report No.2, Protective Technology ResearchCentre, School of Civil and Environmental Engineering, Nanyang
Technological University.
Pan, T.-C., Megawati, K., Brownjohn, J. M. W. and Lee, C. L., 2001b. The
Bengkulu, Southern Sumatra, Earthquake of 4 June 2000 (Mw=7.7):
Another Warning to Remote Metropolitan Areas. SeismologicalResearch Letters, Seismological Society of America, Vol. 72, No. 2, 171– 185.
Park, R., and Paulay, T., 1974. Reinforced Concrete Structures. John Wileyand Sons.
Park, Y. J., and Ang, A. H.-S., 1985. Mechanistic Seismic Damage Modelfor Reinforced Concrete Structures. Journal of Structural Engineering,
ASCE, Vol. 111, No. 4, pp. 722-739.
Paulay, T., Park, R., and Priestley, M. J. N., 1978. Reinforced Concrete
Beam-Column Joints under Seismic Action. ACI Journal, Nov., pp. 585593.
Priestley, M. N. J, Verma, R., and Xiao, Y., 1994. Seismic Shear Strength ofReinforced Concrete Columns. Journal of Structural Engineering, ASCE,
Vol. 120, No. 8, pp. 2310-2329.
Tregoning, P., Brunner, F. K., Bock, Y., Puntodewo, S. S. O., McCaffrey,R., Genrich, J. F., Calais, E., Rais, J., Subarya, C., 1994. First Geodetic
measurement of convergence across the Java Trench. GeophysicalResearch Letters, 21, 2135-2138.
Valles, R. E., Reinhorn, A. M., Kunnath, S. K., Li, C., and Madan, A., 1996.
IDARC 2D Version 4.0: A Program for the Inelastic Damage Analysis
of Buildings. Technical Report NCEER-96-0010, National Center for
Earthquake Engineering Research, State University of New York at
Buffalo.
Zachariasen, J., Sieh, K., Taylor, F. W., Edwards, R. L., and Hantoro, W. S.,
1999. Submergence and Uplift Associated with the Giant 1833 Sumatran
Subduction Earthquake: evidence from coral micro atolls. Journal ofGeophysical Research, 104, 895-919.

12

New Technologies for Urban Safety of Mega Cities in Asia
36

OPTIMAL IMPROVEMENT OF STORMSEWER SYSTEM FOR INNER BANGKOKTAWATCHAI TINGSANCHALI
School of Civil Engineering, Asian Institute of Technology, Thailand
tawatch@ait.ac.th
ABSTRACT
A study area of 3.5 km2 was selected in an inner part of Bangkok. The
area is mostly residential consisting of buildings, pavements, grassland andunbuilt areas. The urban storm sewer system was investigated to findoptimal improvement to alleviate frequent flooding problems due to its
limited capacity. The MOUSE model developed by the Danish HydraulicInstitute was successfully calibrated and verified using two heaviest
rainstorm data on 5 May 1990 and 7 June 1991. It was proposed toconstruct a flood retention pond in the center of the study area to receive
drainage of surrounding floodwater by gravity and to pump it out to Klong
Bang Sue, the main drain canal. The effects of replacement of some small
sewer pipes by larger ones were determined.
The storm sewer system was analyzed for improvement by considering
probabilistic rainfalls. Fourteen different sewer systems of different pipe
diameters, pumping locations and capacities, and flood storage retention
areas were considered. By considering Markov chain process, the transition
probabilities of rainfall patterns and the steady state probabilities were
calculated from past records. The MOUSE surface runoff model was run forseven different rainfall patterns. The computed runoff was used as input tothe pipe flow model wherein hydrodynamic flood routing was performed tocompute flooding depths and discharges. The water levels in the manholes
and the discharges in the sewer pipes were calculated to determine thehydraulic effectiveness of each alternative. The expected annual flood
damages were computed. Considering the objective function of maximum
annual net benefit. A simulation model was used to determine the optimal
improvement of the sewer system. Sensitivity analysis showed that thediscount rate has a significant effect on optimal results while the Manningroughness coefficient has only a little effect.
1.0 INTRODUCTION
The study area is situated in the north of Bangkok and is delineated by
Klong Bang Sue in the north, Klong Sam Sen in the south, Rama 6 road inwest and Phahon Yothin road in the east. The study area is about 3.5 sq. km.
in which 60% are residential areas and 40 % are commercial areas. The
storm sewer system was consisted of a retention pond at the center of thestudy area, a number of pipes forming sewer networks, pumps and gates asshown in Figure 1. The surface area of retention pond is 14,500 m2 and theaverage depth was 1.5 m. When rainfall occurs, runoffs are collected in thesewer system and discharged through the sewer pipes to the main open drain

2337

October 2004, Agra, India

channels - Klong Bang Sue and Klong Sam Sen. A part of runoff flows to
the retention pond and water is pumped out to the main open drains.
Frequent flooding occurs due to limited pipe sizes in the system to carryflow during high floods.
The main objective of this study is to determine an optimal
improvement of the sewer system based on maximum net benefit. The
MOUSE sewer system model developed by the DHI Water andEnvironment (2000) was used for determining the hydraulics of storm sewerflow.
2.0 MATHEMATICAL MODEL
2.1 MOUSE Model
The MOUSE model (DHI Water and Environment, 2000) is a software
package for modeling urban storm sewer systems. The system consists ofsurface runoff model, pipe flow model, pollution model and routines forgraphical presentation of input and output data.
Surface runoff model
The model applies the continuity equation and the kinematic wave
equation in the surface runoff computation. The effective rainfall Peff per unit
area is expressed as

Peff (t )  R (t )  QE (t ) Qw (t ) Qi (t )  Qs (t )(1)where R = rainfall, QE = evaporation loss, Qw = wetting loss, Qi = infiltration
loss and Qs = storage loss and t is the time. The infiltration is calculated byusing the Horton's equation with exponential decay with time. The hydraulicprocess routes the effective rainfall by using the kinematic wave equation
assuming quasi-steady uniform flow of runoff over the surface without timedelay. The runoff Q(t) is determined byQ(t) =

1
5/3
(2)
.B. I 1/2
o .ynwhere n = Manning n, B = runoff width, Io = bed slope, y = flow depth. Also,
Q(t) can be expressed by the continuity equation
Q(t) =dy
A (3)dtwhere A = surface area, dt = time step and dy = change in depth. The water
depth y and the runoff Q(t) can be determined implicitly by solving equations
1 and 2 simultaneously. The surface runoff model computes runoff

24

New Technologies for Urban Safety of Mega Cities in Asia
38

ICUS Report 6hydrographs at nodal points (manholes) in the sewer system for the pipe
flow model computations.
Free surface and pipe flow model
The governing equations for free surface flow are the following
continuity and momentum equations
Q A+= 0 (4)
x
t
2
Q
  Q  y 
++ g A   + g A I f = g A I 0 (5)tx  A  x 

where Q = flow rate, A = cross sectional area, y = flow depth,g = gravitational acceleration, x = longitudinal axis, t = time,  = velocity
distribution factor, I0 = bottom slope, If = friction slope = QQ /(n2A2R4/3),
n = Manning roughness coefficient and R = hydraulic radius.
When full pipe flow occurs, equation 4 can be generalized byintroducing a fictitious slot at the top of the pipe and can be written as: Q Q  g A0  y+ 2+= 0 (6)
x
 x
a t
where the slot width T is defined as T = gA0 /a2 , A0 = full pipe cross sectional
area and a = speed of sound in water (a  1,000 m/s for most pipes).
The outputs from the pipe flow model are discharge, velocity and depthhydrographs. Given the boundary and initial conditions, the discharge Q and
depth h along pipes at different grid points and different time steps arecomputed using Abbott’s six-point finite difference scheme. In order toobtain a stable numerical solution, the following Courant stability condition
has to be satisfied, i.e., t  x / V , where v = flow velocity (m/s), t =time step (seconds), x = distance between computation nodes in m.
2.2 Rainfall Probability
The collected rainfall data at 10 minute interval during the heavy
rainfall period (August, September and October) in 1983-2000 werecategorized into rainfall patterns according to rainfall depth, time to peak ofrainfall and maximum intensity of rainfall (Table 1). The rainfall process
was assumed to constitute a Markov chain having a number of states m = 7.
Using Markov chain process, the probability of rainfall at a certain time step
depends on the probability of rainfall at the previous time step only. The
transition probability of changing of rainfall state from i to j, Tij can becomputed as

Optimal Improvement of Storm Sewer System for Inner Bangkok
39

25

October 2004, Agra, Indiam

Tij  Nij /  Nij

(7)

i 1

where Nij = number of times that the rainfall data is changed from state i tostate j in one time step and,m

Pj   Pi .T ij

(8)

i1

m

 Pj  1(9)i1

where Pi and Pj are the stationary probability of rainfall states i and j. The
stationary probabilities are solved from equations 8 and 9 simultaneously
and are equal to 0.956, 0.012, 0.011, 0.008, 0.005, 0.005 and 0.003 for therainfall states 1 to 7 respectively.
Table 1: States of rainfall patterns
State

Rainfall Characteristics

1

Rainfall Depth
(mm)
<20

≥20

Max. Intensity(mm/min)
<1

2

40-60

≥10

>1.5

3

40-60

≥20

1.0-1.5

4

60-80

≥10

>1.5

5

60-80

≥20

1.0-1.5

6

>80

≥10

>1.5

7

>80

≥20

1.0-1.5

Time to Peak (min)The transition probability of changing of rainfall state from i to j, Tij, can becomputed based on observed rainfall data, e.g., Tij = 0.96, 0.010, 0.010,
0.009, 0.006, 0.003 and 0.001 for i =1 and j = 1 to 7 respectively; Tij =0.78,
0.11, 0.11, 0.0, 0.0, 0.0 and 0.0 for i =2 and j = 1 to 7 respectively, etc.
3.0 MODEL CALIBRATION AND VERIFICATION
System input data to MOUSE model are catchment characteristics andpipe data namely manholes, pump stations and retention basin. The existing
sewer system has 88 sub-catchments, 94 manholes and 99 branches. For
surface runoff model, hydrological input data are rainfall, evaporation,
wetting, depression storage, initial filtration and exponential decay constant.
The time step is 5 minutes. For the pipe flow model, input hydraulicparameters are head losses in manholes for various shapes of outlet. For
numerical stability and convergence, a time step t = 30 seconds and x =100~200 m was used for hydrodynamic computation. The hourly waterlevels data at Klong Sam Sen and Klong Bang Sue were input as the

26

New Technologies for Urban Safety of Mega Cities in Asia
40

ICUS Report 6boundary conditions. The MOUSE model assumes initial pipe flow depth
equal to 10% of the pipe diameter. The Manning roughness coefficient n istaken as 0.017 for rough concrete pipes. The value of Manning n was
adjusted by trial and error in model calibration and verification based on
observed storm data on 5 May 1990 and 7 June 1991 (Moe, 1992).
4.0 ECONOMIC ANALYSIS
4.1 Flood damage cost
From the field data analysis, Tang et al. (1991) proposed the following
quadratic model:
FLD  0. 025 [ a  D  D m   b  D  D m ]
2

(10)

where FLDi = flood damage cost in US dollars per flooded establishment
corresponding to rainfall state i , D = maximum flooding depth above
ground level in centimeters , Dm = minimum flooding depth in which there
is no damage, a = 0.0482, b = 80.26, Dm = 1.63 cm. The total expected flood
damage cost was computed by,
Expected Flood Damage Costm

  Pi ( FLD) i E i
i 1

(11)

where Pi = stationary probability of rainfall state i, m = number of rainfall
states and Ei = number of flooded establishments.
4.2 Pipe cost
The pipe cost data includes cost of excavation and the cost of laying
pipes, i.e., CP  40.3 d1.717 where Cp = pipe cost per meter length in US
dollars and d = diameter of pipe in meters. The pump cost function which
includes the cost of construction and accessories was developed JICA
(1985), i.e. Cpump = 0.1215 Q + 0.54, where Cpump = pump construction costin million US dollars, Q= pump discharge (m3/sec). The operation andmaintenance cost of pumping per year was estimated to be 7% ofconstruction cost.
In the estimation of annual costs, the rate of discount and life ofcomponent was assumed as 10% and 30 years for pipes and 10% and 15
years respectively for pump costs.
4.3 Cost of retention pond
A unit cost of US dollars 137.50 per square meter of additional
retention area was used. The annual cost of retention for a planning periodof 30 years and discount rate of 10% was taken. The optimization of sewer
system improvement is based on the objective of maximizing the annual net
benefit obtained from the flood protection, i.e.
MAXIMIZE Z = MAX (B - C)

Optimal Improvement of Storm Sewer System for Inner Bangkok
41

(12)

27

October 2004, Agra, India

where Z = annual net benefit, C = annual cost and B = annual benefit. The
constraints are pipe diameter di  0.2 m, Qi  0, Dm  25 cm.

CAllnewpipes

 CPL i AllpumpsmCapump  CR   Pi  FLD i . E i
i1

(13)

C = annual flood damage cost in existing sewer system, CP= cost of pipe perm length, CR = cost of retention basin, L = length of pipe in meter, Capump =annual capital pump cost plus operation cost of pump, m= number ofrainfall states. Other parameters were previously defined. The decisionvariables were the diameter di of pipes that need to be replaced, the capacityof the pumps Qi and the surface area of the retention pond. The objectivefunction is a non-linear function in which there are a large number ofdecision variables. As the sewer system is rather complicated, theoptimization based on non-linear programming or dynamic programming
may be very time consuming and even not possible. A simulation techniqueused by Fujiwara and Dayani (1991) was applied to the fourteen alternatives
to find the maximum net benefit for optimal pipe sizes, the pump capacities
and the retention area.
5.0 RESULTS AND DISCUSSIONS
Fourteen different sewer systems are considered by choosing different
diameters of pipes, different locations and capacities of pumps, andretention area (Acharya, 1993). For each sewer system, the flooding depth
and flooding area are calculated by running the pipe flow model. It was
found that the effect of a rainfall pattern on inflow to sewers depends on thedepth, duration of rainfall and the maximum intensity. The rainfall pattern
R6 (Table 2) has the maximum runoff volume and its effect lasts for almost
6 hours. The rainfall pattern R2 (Table 2) produces the least volume offloodwater and time of runoff is also the least. The output from the runoff
model was used as input to the pipe flow model. From the pipe flow model,
the depth of flooding at manhole locations and volumes of floodwater wereobtained for each rainfall pattern and each sewer system. The rainfall
pattern R6 produces the maximum depth of flooding and also generates
maximum volume of floodwater and hence the maximum flood damage cost.
The simulation technique (Fujiwara and Dayani, 1991) was used todetermine the optimal sewer system from fourteen cases. Only commercial
sizes of pipes and box culverts were considered, i.e. diameters of 1.2 m, 1.5
m and 1.75 m, etc. From the results (Table 2) the sewer system no. 8 is the
optimal sewer system because the net benefit is maximum. Also, the total
cost in minimum and the benefit cost ratio is maximum compared to othersewer systems. The average flooding depth for the optimal sewer system isless than 25 cm. and the average flooding duration in less than one hour.
The optimal sewer system (sewer system no. 8) has a maximum B/C ratio of
1.89 and a maximum annual net benefit of US $ 340,000. Sensitivity
analysis was carried out by changing the Manning n from 0.020 to 0.017

28

New Technologies for Urban Safety of Mega Cities in Asia
42

ICUS Report 6

and 0.025 keeping other parameters fixed. It is found that the n value hasvery little effect on B/C ratio and the net benefit. Sensitivity analysis is also
carried out by changing the discount rate i in calculating the annual costs.
The effect of i value was found to be very significant. When the discountrate was decreased, the cost of sewer system decreased and hence thebenefit cost ratio and the net benefit were increased.
6.0 CONCLUSIONS
By classifying observed rainfall by its depth, time to peak andmaximum rainfall intensity, seven rainfall patterns were specified. The
transition probability and steady state probability of rainfall were
determined. By running the MOUSE model, it was found that the rainfall
pattern R6 is the most severe one. A quadratic flood damage function andthe cost models were applied in this study. The objective function is tomaximize net benefit of the sewer system. Due to complicated sewer
systems and nonlinear characteristic of the system benefit and cost, asimulation technique was applied to find the optimal sewer system withmaximum net benefit. Fourteen different sewer systems were considered,
the flooding depth and flooding area were calculated by the pipe flow model.
The sewer system number 8 yields the maximum net benefit, the highest
B/C ratio and the minimum total cost. Sensitivity analysis on the economic
evaluation showed that the discount rate has a significant effect on the
optimization results while the effect of Manning n is insignificant.
REFERENCES
Acharya, B.K., 1993. A Probabilistic Model for the Design of an Urban
Drainage System for an Inner Part of Bangkok. Master Thesis, Asian
Institute of Technology, Pathumthani, Thailand.
DHI Water and Environment, 2000. Modeling of Urban Sewer System.
Danish Hydraulic Institute, MOUSE Documentation, Horsholm,
Denmark.
JICA, 1985. Master Plan For Flood Protection Drainage Project in Eastern
Sub-urban Bangkok. Project Report, Japan International Cooperation
Agency, Japan
Moe, M.M. 1992. Computer Modeling of Urban Drainage System of an
Inner Part of Bangkok. Master Thesis, Asian Institute of Technology,
Pathumthani, Thailand.
Tang, J.C.S, Vongvisessomjai, S. and Kanchanarat, S., 1991. Estimation of
Flood Damage Cost for Bangkok. Water Resources Management, 6(1),pp 47-50.
Fujiwara, O. and Dayani, M.A., 1991. A Semi-Markovian Analysis for
Reliability of Water Distribution Networks. Research Report, Industrial
Engineering Division, Asian Institute of Technology, Pathumthani,
Thailand.

Optimal Improvement of Storm Sewer System for Inner Bangkok
43

29

October 2004, Agra, India

Figure 1: Sewer system of Inner Bangkok and verification of MOUSE
model with observed flood depths, 7 June 1991

30

New Technologies for Urban Safety of Mega Cities in Asia
44

ICUS Report 6



Figure 2: Existing and optimal storm sewer system in study area

Optimal Improvement of Storm Sewer System for Inner Bangkok
45

31

October 2004, Agra, India
Table 2: Results of sewer system optimization, discount rate i = 10%

Annual Cost (Million US$)
Sys-

Con-

Flood

tem

struct O&M

Dam-

ion

age

32

Total

AnnualAnnualBenefit

B/C

(Mil.

Ratio

US$)

Net
Benefit
(Mil.
US$)

1

-

-

0.76

0.76

-

-

-

2

0.17

0.012

0.28

0.46

0.48

1.04

0.02

5

0.58

0.010

0.02

0.61

0.75

1.23

0.14

12

0.31

0.007

0.14

0.46

0.62

1.33

0.16

14

0.31

0.007

0.14

0.46

0.62

1.34

0.16

3

0.30

0.019

0.14

0.46

0.62

1.36

0.16

11

0.53

0.019

0.01

0.57

0.75

1.32

0.18

13

0.32

0.007

0.13

0.45

0.64

1.43

0.19

6

0.52

0.022

0.01

0.56

0.75

1.35

0.20

10

0.34

0.022

0.10

0.46

0.66

1.44

0.20

9

0.41

0.011

0.05

0.47

0.72

1.54

0.25

7

0.42

0.025

0.02

0.46

0.74

1.60

0.28

4

0.38

0.008

0.05

0.43

0.72

1.65

0.28

8

0.32

0.007

0.05

0.37

0.71

1.89

0.34

New Technologies for Urban Safety of Mega Cities in Asia
46

TECHNIQUES FOR MONITORING
DEFORMATION IN LARGE ENGINEERINGSTRUCTURES
MADHAV N. KULKARNI, NISHA RADHAKRISHNANAND DEEPA RAI
Department of Civil Engineering,
Indian Institute of Technology Bombay, India
kulkarni@iitb.ac.in
ABSTRACT
Construction of large engineering structures such as dams, bridges,
high-rise buildings, etc., is essential for the urban development of a nation.
However, under excessive loading, these structures are subjected todeformations, which may lead to their failures, thereby causing loss of lives
and property. The safety of these structures demands their periodic
monitoring. Results from the deformation monitoring measurements enable
us to expand our existing knowledge of the correlation between the loading
factors and the deformations. Thus, the safety control of such structures liesin the analysis of their structural behaviour, based on monitoring a large setof variables, which describes the actions (earthquakes, temperature
variations, wind action etc) and the corresponding stresses.
For the purpose of monitoring and measuring deformation of dams, anumber of methods have been developed. They have been broadly classified
into physical and geodetic techniques. With the advancements in spacetechnology, in the recent years, deformation monitoring and measurements
are being done using Global Positioning System (GPS). With the advent ofmodern instruments, conventional geodetic surveying and physical methods
have been replaced by use of instruments like tacheometers, fiber optic
deformation sensors, GPS, etc.
This paper gives an overview of the physical methods and geodetic
methods used in deformation monitoring and measurement. Deformation
monitoring in bridges using tacheometers are described. The paper also
gives a broad view of how GPS is used for deformation monitoring. A casestudy on Koyna dam deformation monitoring using GPS is presented, alongwith some recent results. The concept used here can also be used in
deformation monitoring of the other structures.
1.0 INTRODUCTION
Large engineering structures such as dams, bridges, high-rise buildings,
etc., are essential for the socio-economic development of a region. However,they need a careful safety control along their life span, since under excessive
loading they might undergo failure, causing loss to lives and property. The
monitoring of the actual state of existing structural buildings has a high71
47

October 2004, Agra, India

importance regarding to the assessment of the reliability and availability.
The security and maintenance of bridges and tall buildings requires periodic
monitoring, maintenance and restoration. Furthermore, accurate knowledgeof the behaviour of the structures is becoming more important as new
structures become lighter, new building techniques are introduced and anincreasing number of existing bridges are required to remain in service
beyond their theoretical service life. Hence, the safety of large engineering
works demands periodic monitoring of the structure and in-depth analysis of
its structural behaviour, based on the monitoring of a large set of variables
contributing to deformation. Thus, the deformation forms the most relevant
parameter to be monitored.
Deformation of large engineering structures is often measured in orderto ensure that the structure is exhibiting safe structural behaviour.
Deformation of a structure is the only single parameter affected by all theloads on the structural system and is an important critical parameter thatwould throw light in a significant measure on the structural behaviour of thestructure (Narayana, 1982).
Several factors contribute to the deformation of these structures. The
most important of all is the result of the varying stress and strains developedin the structure due to the effects of local crustal movements (Manake &Kulkarni, 2002). Other factors may include type of the material, wind
actions, temperature variations, settlement of soil, and fluctuations in theload due to vehicular traffic. Deformation refers to the changes that a
deformable body (natural or man-made objects) undergoes in its shape,
dimension and position. Therefore, it is important to measure these
movements for the purpose of safety assessment and as well as forpreventing any disaster in the future. All deformations or movements are
three-dimensional (3-D) and the several ways of measuring them can bebroadly classified into Physical, Geodetic and Photogrammetric methods
and more recently, the revolutionary space geodetic technique, the Global
Positioning System (GPS) (Kulkarni, 1985) .
2.0 PHYSICAL METHODS
The physical methods used for deformation studies involve the use ofstrain gauges, special thermometers, direct and indirect pendulum, plumbing
equipment etc. Other kinds of instruments used are Carlson Stessmeters,
Carlson Strainmeters, Coordimeters, Tiltmeters, Structural Response
Recorders, Accelerometers and Uplift Pressure cells that are embedded in
the body of the structure. Periodic observations with these instruments canyield some idea about the deformation of the structures. The main
disadvantage of physical methods is that these instruments, deeply
embedded in the body of the structure, are mostly inaccessible formaintenance and repair. These methods give only relative movement ofpoints within the structure as no reference can be made to points outside thestructure. Since they give only relative and not absolute measurements,
these cannot be used for monitoring deformations due to crustal movements.
72

New Technologies for Urban Safety of Mega Cities in Asia
48

ICUS Report 6

Thus they are useful only in estimating the structural deformations(Kulkarni, 1985).
3.0 GEODETIC METHODS
Applications of geodetic technique to geodynamic, monitoring crustal
movements for Earthquake studies and deformation measurements, haveassumed great importance recently (Roy & Kulkarni, 1999). The classicaland modern geodetic techniques being used to establish horizontal, vertical,
gravimetric, geomagnetic, and tidal control networks can be classified as:Terrestrial Techniques includes Geodetic Triangulation, Electronic
Distance Measuring instrument (EDM) Traverse, Astrogeodetic
Methods, Precision Levelling.
Space Techniques includes Doppler Satellite Surveying System,
GPS, VLBI, SLR, LLR, Other Space Geodetic Techniques like
LORAN, DORIS, etc.
Geophysical Techniques in Geodes includes Gravimetric surveys,
Geomagnetic surveys, Tidal observations and predictions.

High precision geodetic instruments including precision theodolites,
precise levels, GPS receivers, EDMs, Gravimeters, Magnetometers, Tide
gauges etc., are being used in India for such geodetic surveys.
4.0 PHOTOGRAMMETRIC METHODS
These methods consist of periodic photography of large structures,targets and pillars, permanent pillars etc., to estimate the displacements.
Photogrammetry provides a new perspective to monitoring work in the waythat photographs are rich of information and can be analyzed at any timewith high repeatability. This method has the advantage of depicting theentire ground surface whereas the conventional monitoring techniques canonly handle discrete point measurements. But however, this method is stillin experimental stage and not being used widely (Tsan-wing & Kin-Wah,2001).
5.0 GPS FOR STRUCTURAL MONITORING
Deformation of engineering structures is often measured in order toensure that the structure is exhibiting safe deformation behaviour. Thereby,
it is necessary to monitor structural deformation due to various factors likemost importantly, seismic activity, wind forces, changes in the ground level,etc.
Physical instruments like Accelerometers, strain gauges and geodetic
instruments like total stations are familiar tools for structural monitoring.
However, relative displacements, which are the key to accessing drift andstress conditions, are very difficult to measure directly with the following
instruments. This is because in order to compute displacements it isTechniques for Monitoring Deformation in Large Engineering Structures
49

73

October 2004, Agra, India

necessary to perform suitable processing. Although acceleration
measurements by accelerometers are useful for accessing design/analysis
procedures and correlating the response of the structure they are inadequate
for warning of potential failure or even recovering the permanent responseof the event. Further limitations on monitoring are imposed by the high costof equipment installation and maintenance. The regular monitoring ofstructures often require measurements of relative displacements, which may,in turn, be used to access the structure’s stress and drift conditions during
seismic events or wind forces (Tsakeri & Lekidis, 2001).
Recent advances in GPS technology have made it a cost-effective tool
for monitoring the safety and performance of structures. It has theadvantage of directly providing displacement information in absolute aswell as in real time, making it a competitive alternative to the conventional
surveying methods. GPS provides 3-D positions with reference to a fixed
global coordinate system, simultaneously at all sites, with automated datacollection and no line-of-sight requirement. It can provide continuous
updating of positions of GPS receivers within few-mm accuracy withrespect to stable points up to several km away. Furthermore, GPS satellites
are not affected by earthquakes. The recent development in the field ofstructural monitoring applications is the advances in GPS receivertechnology and data processing software. The collected information can beused to make decisions for further evaluation of the susceptibility to damage
and future repair schemes for the dam. Hence, many dams worldwide arebeing monitored using this technique [Manake & Kulkarni (2002)].
6.0 BRIDGE DEFORMATION MONITORING
The monitoring of a new or existing bridge can be approached either
from the material or from the structural point of view. In the first case,monitoring will concentrate on the local properties of the materials used
(e.g., concrete, steel, timber, composite materials) and observe their
behaviour under load, temperature variations or aging.
In the structural approach, the structure is observed from a geometricalpoint of view. By using long gauge length deformation sensors withmeasurement bases much larger than the characteristic dimensions of thematerials (for example a few m for a concrete bridge), it is possible to gain
information about the deformation of the whole structure. Structuralmonitoring has usually been realized using external measuring methods liketriangulation, dial gauges and invar wires. At present, geodetic methods liketacheometers have gained great importance in monitoring deformations inbridges (Inaudi et al. 1999).
6.1 Tacheometers in bridge monitoring
The use of Tacheometers for monitoring bridges is one among themany geodetic techniques. Currently, new tacheometers are being used tomeasure distances without a reflector up to a range of 200 m (TRIMBLE
74

New Technologies for Urban Safety of Mega Cities in Asia
50

ICUS Report 65601).
This instrument fulfills the following requirements.
The
requirements being the time of measurement should be less than 3 hours.
Measurements should be possible under traffic load. No point marking
should be involved and a reproductive accuracy of deformations of 5 – 10mm within several years must be obtained. It should be suitable formonitoring bending of the superstructure and displacements of pillars andabutments. The technique should also involve automatic data processing.
These tacheometers can scan and determine the building shape. With thisinformation calculations of deformations are possible (Kuhlmann & Glaser,1999).
Basic principle of the procedure is to derive the deformation of thebuilding by comparison of shape and not by evaluation of movement of
single points. For comparing of shape, the following Figure 1 has been
considered.

Figure 1: Deviation in a bridge zone
(Kuhlmann & Glaser, 1999)
For comparing the shape, geometrical objects are formed from themeasured zone points. In detail the inclination and shape of the pillar andsuperstructure are studied.
This is done as follows:Inclination and shape of the pillar: They are described in theprocessing by angle α of a fitting straight line in comparison toplumb line, and by deviations from this straight line.
Inclination and shape of the superstructure: They are described in
the processing by angle α of a fitting straight line in comparison toa horizontal line, and by deviations from this straight line.

For calculation of the pillar inclinations every pillar side is consideredseparately. An average pillar inclination can be computed from the rightand left side inclination.

Techniques for Monitoring Deformation in Large Engineering Structures
51

75

October 2004, Agra, India

7.0 HIGH-RISE BUILDING DEFORMATION MONITORING
Due to the outcome of several severe earthquakes in the recent years,
drift studies and assessment of susceptibility to damage of tall buildings
have become important issues, particularly as many steel-framed buildings
are damaged, some severely and some lightly.
Relative displacements, which are the key to assessing drift and stressconditions of structures, are difficult to measure directly. On the other hand,measuring acceleration response requires a double integration process toarrive at displacements. Accelerometer measurements cannot be used torecover the permanent displacements at the cm level. The level of accuracyof displacements calculated from accelerations has not been widely verified
by observations. An alternative method to measure relative displacements
while monitoring structural systems can be accomplished by using GPS
technology. This has now advanced to 10 samples per second with anaccuracy of ± 1 cm horizontally and ± 2cm vertically (Celebi et al. 2001).
This provides a great opportunity to reliably monitor long-period structures(tall buildings).
In the recent years, GPS has found to be highly significant inmonitoring deformation of large engineering structures. A study on how
GPS is used in monitoring the deformation of Koyna Dam is explained. The
Indian Institute of Technology Bombay (IITB) has been working in the fieldof deformation measurements and analysis of Koyna Dam under a research
project funded by the Department of Science and Technology (DST),
Government of India. A GPS network has been established for this purpose,and observed over nine epochs, from December 2000 to April 2004, in order
to investigate the potential of the GPS Technology in deformation
measurement analysis.
The study highlights methodology, analysis
techniques and the results of the research work being carried. The analysisof results indicates a correlation between the change in the reservoir level
and the deformation of the dam. Similarly, the same application and conceptof measurement can also be used for estimating the degree of deformation inbridges and tall buildings.
8.0 CASE STUDY: KOYNA DAM, MAHARASHTRA
Koyna Dam, a rubble concrete dam, located on the Krishna River, isan 85 m high and 800 m long rock-filled structure, with an 872 sq km ofcatchment area. The dam and the reservoir formed went under constructionin 1962 and were completed in 1963. They are located on the Indian
Peninsular shield, one of the oldest continental blocks on the earth’s surface.
Prior to the year 1962, this shield was referred to as a stable rock bygeologists, which remained immune from any major seismic disturbance.
But the December 11, 1967 earthquake at Koyna at approximately 4.21 am
local time, with a magnitude of 6.6 – 7.5 on Richter Scale, contradicted thisbelief and evoked interest on the part of geologists, geodesists, dam experts
and engineers. However, the dam in the region withstood this significant
76

New Technologies for Urban Safety of Mega Cities in Asia
52

ICUS Report 6

seismic activity without much damage. This occurrence in the Central
Indian shield has led to serious introspection among geo-scientists and led tovarious studies dealing with the stability of the dam structure and thesurrounding regions [Manake & Kulkarni (2002)].
Thus to study some of the factors that might be affecting the dam, it
has been well instrumented for observations of structural behaviour, rightfrom the design stage, and has proved to be significant. The instrumentation
include physical instruments embedded in the dam structure or installedaround the dam body like uplift pressure cells, thermometers, piezometers,
stress and strain meters and coordimeters and these have been providing
data since 1969. Apart from this, the advances in technology have evoked
the use of GPS for carrying out dam and crustal deformation studies. The
advantage of providing positions simultaneously at all sites, automated datacollection, no line-of-sight requirement makes GPS more economical,
efficient and convenient, as compared to the conventional surveying
techniques. IITB in collaboration with DST has been working in the field ofmonitoring deformation of Koyna Dam from September 2000. The main
objective of this work is to study the seismologically disturbed region of
Koyna area and the behaviour of the dam body, using geodetic GPStechnique. It includes establishing dense GPS network in the identified
seismically active area, its repeat observations, detailed GPS data processing
using scientific software and to estimate parameters responsible for
deformations.
8.1 GPS network
In order to carry out structural and crustal deformation studies, anextensive GPS network comprising 34 stations has been established in thevicinity of Koyna Dam, at the beginning of the project, in December 2000January 2001. The GPS network set up in order to monitor the complete
area is given in Figure 2.
The distribution of the GPS stations is One base station on the dam
axis, established approximately at the centre and the top most point of thedam; Six stations on the dam axis (Three on either side of the base station);
Three stations on the dam pier (Two on upstream (U/S) side & one on
downstream (D/S) side); Three station on dam base (All on D/S side); One
GT Station connected: Jangli Jaigad H. S situated approximately 8 km northof the dam; One at IIG (Indian Institute of Geo-magnetism) Observatory andone at Evaporation Lab; Eight GPS stations (fault points) along the fault line
D/S of dam; Three back site stations (All on D/S side); Two safety stations(All on D/S side); Five deformation stations (All on D/S side)

Techniques for Monitoring Deformation in Large Engineering Structures
53

77

October 2004, Agra, India

Figure 2: GPS Network established in the Koyna region.
(Manake & Kulkarni (2002))
The observations at the selected points were taken using dual
frequency geodetic GPS receivers: 4000SSi with Choke Ring antenna and
5700 with Zephyr Geodetic antenna. The data is collected for a period of 68 hours with a sampling rate of 15 seconds, and satellite elevation mask of
15°. Repeat observations over the entire network have been carried out
starting from Dec 2000. Till date, nine sets of observations have been taken(Dec. 2000, May 2001, Oct 2001, Sept 2002 and Dec. 2002, May 2003, Sept
2003, Dec 2003, April 2004), each fieldwork period spanning approximately
three weeks.
8.2 Methodology for data processing and analysis
The objective of the work was to identify the factors responsible for
deformation of the dam and their impact on the dam points and thesurrounding region. The major factors that have been identified and studied
in this project were the plate motion, varying reservoir water table. Other
factors include seismic activity along fault zone, temperature, seepage,erosion, and settlement changes in the subsoil etc, which have not been
included in this study.
The data is being processed using Bernese v4.2, which is a scientificsoftware developed by the University of Bern. The processed data yieldcoordinates and baselines in both Cartesian Rectangular and Geodetic
coordinate systems. All the changes in the coordinates and baseline lengths
between the subsequent repeat observations (campaigns) have been
established, and this gives the degree of global deformation between the
campaigns. The global deformation includes the displacements caused due

78

New Technologies for Urban Safety of Mega Cities in Asia
54

ICUS Report 6

to crustal (plate) motion, water level, seismic activity due to fault zone andother factors like subsidence etc.
In order to study the deformation of the dam due to continuously
fluctuating water table, the base station on the dam axis was analysed.
Continuous observations were taken for the base station throughout all thecampaigns. The change in the coordinates of the point between the
successive campaigns was estimated and the deformations thus obtained
were studied to understand the pattern of deformation with respect to change
in the water table.
8.3 GPS results and deformation analysis
The change in the coordinates obtained from GPS yield the global
deformation of the points, which include two components, namely the local
deformations and the plate deformation (of the Indian plate). In order tounderstand the deformation pattern of the dam, it is necessary to exclude theplate deformation from the global deformation to give the local deformation.
For this purpose, the coordinates of IGS station IISc was used to computethe plate motion between the successive campaigns. Since IISc and Koyna
are on the same plate (Indian plate), the deformation reflected in the Koyna
points with respect to IISc would yield purely the local deformations. The
local deformations of the base station for the successive campaigns were
calculated and this is given in Table 1.
Table 1: Local deformations of the Base Station(Global deformation – Plate motion)
SL
No

Campaigns

1
2
3
4
5
6

Dec00-Oct01
Oct01-Sept02
Sept02-Dec02
Dec02-May03
May03-Sept03
Sept03-Dec03

Globaldeformation
(mm)
92
43
18
12
16
10

Plate motion Local(mm)
Deformation
(mm)
97
-5
48
-5
13
5
22
-10
18
-2
08
2

(Negative sign indicates the point moves in the direction of plate motion, i.e., NNE;
Positive sign indicates motion opposite to plate movement)

An attempt was made to correlate the global and local deformations of
the base station with the water level for all the eight successive campaigns.
This was done to understand the pattern of deformation of the dam withrespect to change in water level. For this purpose, the standardized waterlevel (z) for three years from 2000 – 2003 (the eight campaigns from Dec00– Dec03) were computed.

Techniques for Monitoring Deformation in Large Engineering Structures
55

79

October 2004, Agra, India

The standardized water table is given by the formulaz(Waterlevel  MDDL)( MWL  MDDL)

where MDDL (minimum drawdown level) and MWL (mean water level).
MWL is taken as 659.90 m, which is the mean of the water levels recorded
since 1969 and MDDL so far recorded since 1969 is 609.60 m. The watertable and the z values for 3 years are given in Table 2. The change in the z
values (Δz) between the successive campaigns are given in Table 3.
Table 3: Change in z between
successive campaigns

Table 2: Standardized Water table z
Campaigns
Dec00
May01
Oct01
Sept02
Dec02
May03
Sept03
Dec03

Water level(m)
649.81633.83654.95657.76649.48632.94656.95650.05z
0.79940.48170.9016
0.95750.79280.46400.94140.8042Campaigns
Dec00-Oct01
Oct01-Sept02
Sept02-Dec02
Dec02-May03
May03-Sept03
Sept03-Dec03

Δz0.10220.0559-0.1647-0.2880.4774-0.1372

At Koyna, from earlier studies done by experts, it has been reported
from physical instrumentation data analysis that the deflection of the dam
increases very gradually for the water levels upto 625 m and increases
rapidly for water levels beyond 625 m. Keeping this factor in mind, apolynomial in Δz was fit to the GPS local deformation data. It was foundthat polynomial in Δz of third degree fits well and this is shown in Figure 2.

Figure 3: Deflection of Koyna Dam – Regression of deflection on water
level
80

New Technologies for Urban Safety of Mega Cities in Asia
56

ICUS Report 6

From the figure, a correlation of 0.9926 is observed. This clearlyshows that the deformation of the dam is entirely due to the varying watertable. This confirms the fact that the displacement of the structure may besolely because of the water table.
9.0 CONCLUSIONS
Several techniques have been developed for monitoring structuraldeformation of bridges, and high-rise buildings which from the steppingstone to urbanization. Since several years, physical and geodetic surveying
methods have been widely used to monitor displacements of these structures.
In the recent years, advancement in technology has led to the developmentof modern measurement methods like long gauge length deformation
sensors, tacheometers with automatic reading and recording features tomonitor deformations. The advancement in Space Geodesy has resulted in
the use of GPS in structural deformation studies, since it overcomes thelimitations of the terrestrial geodetic techniques. GPS has been widely usedin monitoring of several types of structures, especially large dams, like
Koyna Dam in India. The concept of monitoring deformation, as
implemented by IITB GPS team for deformation analysis with respect towater level for the Koyna Dam, can also be applied to other type ofstructures.
REFERENCES
Celebi, M., Prescott, W., Hudmut, K., Behr, J., 2001. GPS monitoring ofstructures: Recent Advances. Proc. 30th Joint meeting of US-Japan cooperative Programme in Natural resources, August, San Francisco,
U.S.A.
Inaudi, D., Casanova, N., Vurpillot, S., 1999. Bridge Deformation
Monitoring with Fibre Optic sensors. International Association for
Bridge and Structural Engineering symposium, August 25-27, Rio deJeneiro, 475.
Kuhlmann, H., Glaser, A., 1999. Investigation of new measurement
techniques forBridge monitoring, Institute of Application of Geodesy to
Engineering, Germany.
Kulkarni, M.N., 1985. Dam Deformation Studies by Geodetic method,
Indian Surveyor, January, Journal of the Institution of Surveyors, India,
23.
Manake, A., Kulkarni, M.N, 2002. Study of the Deformation of Koyna Dam
using Global Positioning System, Survey Review, July 36(285), 497.
Narayana, G.S., 1982. Role of Geodetic Measurement in Survelliance ofDams. Internal Report, Special Analysis & Instrumentation Directorate,
Central Water commission, New Delhi.
Roy, B.C., Kulkarni, M.N., 1999. Geodetic and Geophysical aspects ofMonitoring Seismotectonics in India. Indian Surveyor, January, 15.
Tsakiri, M., Lekidis, V., 2001. The use of GPS for Monitoring Cable-stayed
bridges in Seismic areas. International Association of Geodesy
symposia, 125, 347.
Techniques for Monitoring Deformation in Large Engineering Structures
57

81

October 2004, Agra, India

Tsan-wing, N.G., Kin-Wah, L., 2001. Application of Photogrammetry inMonitoring of Marine Rubble Structures. The 10th FIG International
Symposium on Deformation Measurements, Session II, Orange,
California, U.S.A, March 19-22.

82

New Technologies for Urban Safety of Mega Cities in Asia
58

DEVELOPMENT OF SLOPE FAILUREDISASTER MANAGEMENT SYSTEM IN
URBAN AREA THE UTILIZATION OF
EXISTING DATA TOWARD“E-MUNICIPAL GOVERNMENT”
AKIYUKI KAWASAKI AND SATORU SADOHARA
Yokohama National University, Japanakiyuki@arc.ynu.ac.jp
ABSTRACT
Slope failure disaster management system in Yokohama, Japan, isunder development using existing municipal government data and GIS, inorder to improve steep slope management activities. Three basic
methodologies for predicting dangerous slopes and sand covering areas areproposed in this study:Specifying steep slopes and sand covering areas in large city areas
automatically using DEM (Digital Elevation Models) and
LandUse data using GIS raster and vector analysis.
Forecasting dangerous areas for slope failure with rainfall datausing GIS. As a provoking cause for collapse, collapse records andrainfall data observed at 98 points in Yokohama every 15 minutes
are analyzed.
Statistical analysis of the possibility of slope failure disaster, using
steep slope inventories by municipality, and multivariate analysis:
Quantification Theory Type II. Relationships between collapse andthe slope's factors (primary cause for collapse) are analyzed.

By combining these three methodologies, a “Real-time evaluation
system against slope failure disaster” can be completed. As a conclusion ofthis paper, a prototype system was developed. This system consists of two
components:

A Slope Information Management System for effective daily
support of steep slope management activities by integrating
municipal data related to steep slope management (inventory,collapse record, and precipitation). All data are linked to the map.
Searching, retrieving, and updating “Steep Slope data” areallowed, and can be shared by the Internet.
Real-time Slope Failure Prediction System for response activities
after a collapse by accumulation and analysis of slope failure
records and precipitation data. The system development
environment is as follows: OS: Windows XP; DB: Geodatabase(SQL Server2000 by MS ); GIS Engine: ArcObjects by ESRI;

83
59

October 2004, Agra, India


Digital Map: Digital Mapping by Municipality of Yokohama;Analysis Software: Excel Statistics 2000 and SPSS 12.0
1.0 INTRODUCTION
Slope failure disasters must be measured in Japan where they often
occur. Recent efforts to develop soft-measures are underway because hardmeasures, like covering hillsides with concrete, create economical andenvironmental problems. This paper demonstrates how to develop systems
to manage slope failure disaster for municipal governments. Areas prone toslope failure disasters are predicted in real time using GIS and rainfall data.
Also, a database system was developed to combine spatial data with existing
paper data about potential slope failure disasters. This project provides anexample of how existing hardcopy documents can be digitized and used tomake "e-government" a reality.
2.0 OBJECTIVES
The purpose of this study is to create a “slope failure disastermanagement system” by existing data and documents in municipal
government. We believe that making use of paper inventories are important
to assist municipal slope failure disaster management and it will reduce thedamage of slope failure disasters with a small budget and people. The
objectives of the development are shown below:Link existing paper inventories with steep slope areas calculated
by computer.
Collect slope failure disasters record and analyze factors ofcollapse.
Near real-time slope failure disaster prediction based on analysis
and precipitation data.

The flowchart of the development is shown in figure 1.

Figure 1: Flowchart of the development

84

New Technologies for Urban Safety of Mega Cities in Asia
60

ICUS Report 6


3.0 METHODOLOGIES
Three methodologies to develop a “real time slope failure disastermanagement system” are proposed in a series of our study. Details of eachmethodology are on papers of Kawasaki (2001) and Kawasaki (2003).
3.1 Methodology of specifying “steep slope” and “predicted damagearea”.
This method could be used in order to predict which buildings would
be damaged by the collapse. Two GIS data: Land Use and 25m DEM, areused to specify steep slopes and damaged area. The model to specify “steep
slopes” and “the predicted damage area” are shown in Figure 2. Spatial
analysis functions by ESRI ArcGIS were combined in the model.
The result of the model was inspected in Minami-ku, Yokohama city
(Figure 3): 191 areas specified by the model were matched with the areas
specified by local governments out of 204. In other word, 93.6% of theareas specified by local governments were covered by the methodologies.
The predicted damaged area is calculated by the height of steep slope.
It means that higher steep slope has longer damaged area. As a result ofinspection, actual height of a slope was multiplied the calculated height by
0.87.
3.2 Evaluate the primary cause, using “steep slope inventories” and“multivariate analysis; quantification theory type II”.
City of Yokohama inspected 3400 steep slopes in all around the city.
Thirty detailed factors such as geology, height, vegetation, surface thickness,leaking water, etc., were inspected and ranked for its danger. In this study,nine important factors were quantified in order to multivariate analysis foreach slope pattern. In Yokohama city, steep slopes were categorized to four
patterns (Yokohama city steep slope evaluation committee, 2000)
Table 1 is the result of quantification theory type II for slope pattern
No. 1. Each value means the contribution-ratio for the collapse. Higher
value contributes to collapse strongly, while minus value is lower
contribution. Regarding slope pattern No. 1, “ Over-hang”, “Loosenessrelaxation”, and “Leaking water” are common strong factor for the collapse.
On the other hand, “vegetation” tends to prevent slope collapse. Moreover,sum of values can be used to evaluate the possibility slope failure based on
the past collapse record.
Figure 4 represent that most steep slopes which have value higher
than around 0.2 were actually collapsed in the past. Therefore, if a slope had
a value of higher than 0.08, it has strong potential of collapse in the future.
As a result of our verification, the potential of collapse can be estimated in
87% of its accuracy.

Development of Slope Failure Disaster Management System in Urban Area
61

85

October 2004, Agra, India
元 デ ータc.自然的土地
利用ポリゴンa.土地利用LandUse被 災危険区 域の抽出
Predicted-damaged
area

崖
区域Slope
の抽 出
Steep
g.崖区域
ポリゴン

d.TIN

e.TIN
ポリゴン

f.急傾斜地
ポリゴン

Steep
slope
m.崖ポリゴンb.ＤＥＭ

n.バッファ
の発生（属性：区域・高さ）

i.最大値

DEM
h. GRIDk.高さを算出

p.被災
危険区域

l.高さ GRID

Predicted

j.最小値

e.‘ 斜面方向
ポリゴン

m.‘ 崖ポイント

o.斜面方向のdamaged
area

ライン作成

（属性：斜面方向・高さ）

Figure 2: Process of extracting dangerous slopes and zones suffering form
slope failures.

Figure 3: Left; Specified areas of this model (painted) and the areas by
local governments (slashed), Right; Example of 3D
visualization.
3.3 Forecasting the dangerous area for slope failure by rainfall data at
the time using GIS spatial analysis.
In this step, a methodology to specify dangerous area for slope
failure by one hour and three days accumulated rainfall using GIS raster
analysis was proposed. Figure 5 shows relationships between collapses andrainfall (One hour rainfall and three days accumulated rainfall) in
Yokohama city. As a trial, a approximate expression is calculated on thegraph.
As Figure 6 shows, when one hour rainfall and three days rainfall
data was put into ArcGIS spatial analyst with the approximate expression
for slope failure, then ArcGIS calculate dangerous area for slope failure at
the time. This methodology will allow specifying the dangerous area for
slope failure every time the rainfall data is available. Red areas on figure 6
represent the area where rains exceeded that approximate expression. From
the result of verification, about 75 % of actual collapse points were coveredby the areas specified by this methodology. This relationship is important tomake a real-time estimation, because rainfall data can be available every
quarter hour in Yokohama.

86

New Technologies for Urban Safety of Mega Cities in Asia
62

ICUS Report 6

Table 1: Results of Quantification Theory Type II
Item

Category

Height of Slope
(Hm)

Slope
(degree)

Vegitation

Surface Water(above)Surface Water(slope)Drainage on top

Relative frequency

崩壊あり

崩壊なし

- 40°
50cm - 50cm
Exist
No
Exist
No
Bare groundtree
grass/field
tree＋grass/field
Exist
No
Exist
No
Bad/Uncompleted
Good
Exist
No

Over Hang

0.4-0.378
0.086
0.485
0.272
-0.107-0.2190.644-0.0781.296-0.0741.207-0.146-0.346
0.151
0.278
0.050
0.190
-0.1710.160-0.2090.013-0.0360.018-0.002- 5m
60°40°- 60°

Leaking Water

Weightd
coefficient

24
38
12
23
44
7
8
66
4
70
8
66
17
5
11
41
35
39
42
32
54
20
7
67

10m 5m - 10m

Thicknessof Surface

Looseness
Relaxation

Num. ofsampleRange

partialcorrelation
coefficient

0.863

0.224

0.491

0.125

0.722

0.171

1.370

0.255

1.353

0.311

0.624

0.159

0.361

0.134

0.369

0.158

0.049

0.018

0.020

0.005

No collapse

0.3

Actual collapsed

0.2

0.1

0.0

-2.0 -1.5 -1.0 -0.5 0.0 0.5

1.0 1.5

2.0

2.5

3.0 3.5 4.0 4.5 5.0

Sample score

Figure 4: Frequency distribution of distinction result

Development of Slope Failure Disaster Management System in Urban Area
63

87

October 2004, Agra, IndiaOne hourrainfall (mm)
1時間雨量(mm)

30
25
20
15
10
5

Y = － 0.174 X + 28.4
0
0

50

100
7KUHHGD\VDFFXPXODWHGUDLQIDOOPP 
3日間累積雨量(mm)

150

200

Figure 5: Relationship between rainfall and slope failure

Y = ‐0.174X +28.4(“RasterCalculation” )Figure 6: Dangerous area at the time by rainfall data (August/22/2001)
4.0 PROTO TYPED SYSTEM DEVELOPMENT
4.1 System design
The final objective of this study is to develop a slope failure disastermanagement system to support disaster management works in municipality.
In this moment, two trial systems were developed. 1. “Slope Information
Management System”, which is used for daily disaster management use. 2.
“Real-time Slope Failure Prediction System”, which is for preparedness andemergency response work after disasters.
Municipality’s data related to slope failure (inventory, collapse record,and precipitation) were stored and managed using ArcGIS and ArcSDE(Spatial Database Engine), and three methodologies are integrated into thesystem for risk estimation and real time slope failure prediction. The system

88

New Technologies for Urban Safety of Mega Cities in Asia
64

ICUS Report 6

flow is shown in Figure 7. The system is divided into four parts:“Management”, “Analysis”, “Prediction” and “Response”. Proto-typed
system on two parts: “Management” and “Prediction” have been developedin this paper. The other two parts: “Analysis” with data ware house and“Response” for municipality, fire department, and local residents are underdevelopment. The system development environment is shown in Table 2.
Table 2: The system development environmentOS
Database
GIS Engine
Digital Map
Analysis Software

Windows XP Professional
ESRI Geodatabase (SQL Server2000 by Microsoft)
ArcObjects by ESRI
Digital Mapping by Municipality of Yokohama
Excel Statistics 2000 and SPSS 12.0

Figure 7: Flowchart of System design.
4.2 Trial development of slope information management system
Slope information management system is designed for the daily
disaster management use in municipality. Figure 8 shows interfaces of thesystem. Main functions in the system are: A. data input, and B. data
searching and retrieving. Data input interfaces are based on the paper format
of “Steep Slope Inventory”. The format of “Steep Slope Inventory” is basedon the guidelines by Ministry of Land, Infrastructure and Transport. All ofslope inventories have attached the linkage with digital map by municipality.
It will allow searching a slope by the address list box or clicking on the map.
Then, GIS data such as a boundary, road, evacuation area, buildings andDevelopment of Slope Failure Disaster Management System in Urban Area
65

89

October 2004, Agra, India
steep slopes could be overlaid on map window. Also, data related toneighborhood, and pictures are available.
Personnel in municipality can input detailed attribute data of a slope
for inventory work. Then, pop up windows will help data input work. Thiskind of functions would reduce input misses; paper inventories had many ofit though. These functions are required if a system has an analysis functions.
The searching and retrieving functions are required for querying asteep slope by its attribute. Then, system displays the place and attributetable of the slope.

Figure 8: Interfaces of Slope Information Management System.
4.3 Trial development of real-time slope failure prediction system
Proto-typed system of real-time slope failure prediction byaccumulation and analysis of slope failure data, and precipitation data

90

New Technologies for Urban Safety of Mega Cities in Asia
66

ICUS Report 6


updated every 15 minutes, was developed. In Yokohama, precipitation data
at 97points around the city is available every 15 minutes. This system isreceiving rainfall data automatically thorough the Internet, and processing
the data to calculate. Information of observation points and the graphs of theshort-time rainfall and the long term accumulated rainfall data at the time
are shown in the interface (Figure 9). The result of the prediction will beshown on the window when rainfall exceeds a critical line. In addition,using the function of Data warehouse, all data can be stored and used forfurther analysis in order to improve prediction.

Figure 9: Interfaces of Real-time Slope Failure Prediction System.
5.0 CONCLUSIONSSlope failure disaster management system in Yokohama, Japan, isunder development using existing municipal government data and GIS.
Three basic methodologies for predicting dangerous slopes and sandcovering areas are proposed in this study:Specifying steep slopes and sand covering areas using DEM
andLandUse data using GIS raster and vector analysis
Forecasting dangerous areas for slope failure with rainfall data using
GIS,
Statistical analysis of the possibility of slope failure disaster, using
steep slope inventories by municipality, and multivariate analysis:
Quantification Theory Type II.

Development of Slope Failure Disaster Management System in Urban Area
67

91

October 2004, Agra, India
By combining these three methodologies, a prototype system of“Real-time evaluation system against slope failure disaster” was developed.
This system consists of two components:

Slope Information Management System for effective daily supportof steep slope management activities by integrating municipal data
related to steep slope management.
Real-time Slope Failure Prediction System for response activities
after a collapse by accumulation and analysis of slope failure records
and precipitation data.

In next step, using advanced data such as high resolution remotesensing and laser profiler data, the precision of methodologies for evaluating
and predicting slope failure disaster have to be improved. In addition,
thorough a questionnaire and interview to users, system development needs
further improvements as to be a decision-making support tool in practicaldisaster management work in municipality.
ACKNOWLEDGEMENT
Special thanks to YNU Gake-team members for their dedicated work
to this study: Mr. FANG Ji, Mr. IMAMASU Keisuke, Ms. INAGAKI Keiko,Ms. IRIBE Yoshimi, Mr. Li Long Ji, Mr. OKANISHI Yasushi, Ms.
OKUMURA Mako, Ms. Rizka Oktora Ibrahim, Dr. YOSHIDA Satoshi, Mr.
WANG Jin, and Ms. WANG Dongzhi.
This work is contribution to the 2004 Research and Development ofConstruction Technologies by the MLIT (The Ministry of Land,
Infrastructure and Transport).


REFERENCES
Kawasaki, A., Sadohara, S., 2003. The Utilization of GIS for the Measureagainst Slope Failure Disaster in Urban Area, Joint Workshop on USJapan Cooperative Researches in Urban Earthquake Disaster
Mitigation. Unpublished report, Los Angels, California, USA.
Kawasaki, A., Hattori, K., Urakawa, G., Nakajima T., And Sadohara, S.
2001. The Utilization of GIS for the Measurement against Slope Failure
Disaster. Theory and Applications of GIS, Vol.9, No. 2, 25-32.
(Japanese)
Kawasaki, A., Yoshida, S., And Sadohara, S. 2003. Statistical researches ofthe factors affecting slope failure in Yokohama. J. Archit. Plann., AIJ,
No. 569, 125-130. (Japanese)
Yokohama City Steep Slope Evaluation Comitee, 2000. Report of theevaluation of slope failure disaster in Yokohama City. Unpublishedreport, Yokohama, JAPAN.

92

New Technologies for Urban Safety of Mega Cities in Asia
68

NUMERICAL MODELING OF STEELSTRUCTURES IN FIRE CONDITIONS USING
IMPROVED APPLIED ELEMENT METHODSAID A. ELKHOLY AND KIMIRO MEGURO
Institute of Industrial Science, University of Tokyoelkholy@prelude.iis.u-tokyo.ac.jp
ABSTRACT
Steel structures are widely used for buildings due to the advantages ofhigh strength, good ductility and fast fabrication and erection. However,
unprotected steel structures suffer serious damage or even collapse in a firedisaster due to the progressive deterioration in both strength and stiffness ofstructural steel with increasing temperature. To protect life and reduce firedamage to property and financial loss, a steel structure must be designed tohave the ability to sustain the applied design loads without the occurrenceof excessive deflection or even failure in structural members for a specified
period of time in the case of a fire.
In this paper, the Improved Applied Element Method (IAEM), which
was originally developed as an effective analysis technique of large-scale
structures up to complete failure under different hazard loads, has been
progressively developed to carry out modeling the behavior of plane frame
steel structures in fire. The paper presents the methodology of a new
approach for thermal analysis of the large deflection behavior of steel
structures at elevated temperatures. IAEM has been developed to cover bothgeometric and material nonlinearities, including the changes to material
properties as temperatures increase. Rigorous treatments of thermal
analysis in plane frame steel structures are illustrated. The effectiveness andvalidation of the proposed approach are demonstrated by comparison its
results with those previously obtained by benchmark experiments or byother independent computer software.
1.0 INTRODUCTION
To obtain full knowledge of the total behavior of steel structures underfire, it is essential to simulate the collapsing process and the trace ofyielding and deformation at each structural member. The reliable numericalmodels are highly required as a cost effective method of obtaining acomprehensive knowledge of the main parameters that affect response ofstructures under fire. The advanced analytical methods enable engineers to
predict the type and range of possible collapse in both the design stage andafter incidents to enhance the safety of people in structures subjected to fire.
In order to include nonlinear temperature distribution across thesection and along the member, the effects of material and geometric
nonlinearities, thermal strain and creep strain at elevated temperatures
several techniques have been introduced during last four decades. These
121
69

October 2004, Agra, India

techniques can be classified into two main categories depending on theformulation procedure of implementing the constitutive relations. The firstcategory bases on the finite element method (FEM). Based on FEM,
numerous researchers had developed a number of formulations or computer
packages (such as: Cheng and Mak, 1975; Bailey, 1998). The accuracy of
those formulations depended mainly on the adopted models for simulating
the nonlinear material properties and the creep law.
The second category of the numerical approaches bases on plastic
hinge technique (Wong et al. 1998; Vimonsatit et al. 2003). The plastic
hinge approach is less computationally intensive and usually gives goodpredictive accuracy compared to the rigorous finite element approach(Vimonsatit et al. 2003).
None of the methods based on the discrete elements approach have yet
been developed for carrying out the thermal analysis. Therefore, in thispaper, the first implementation of the thermal analysis in the field ofDiscreet Element based approach is presented. This feature allows, not only
to follow the total behavior of structures at elevated temperature, but also
the analysis can extend up to complete failure.
2.0 IMPROVED APPLIED ELEMENT METHODIAEM is a newly developed method for structural analysis of largescale plane-frame structures under hazardous loading conditions. It canfollow total behavior of structures up to complete failure stage with highaccuracy in reasonable CPU. In IAEM, each structural member is divided
into a proper number of rigid elements connected by pairs of normal andshear springs uniformly distributed on the boundary line between elements.
Two major extensions of the AEM (Meguro and Tagel-Den, 2001) havebeen implemented in IMEM: The first is improving the element type to use
different thickness per each spring to be able to follow change of thickness
in non-rectangular cross-sections. The second is using different thicknesses
for calculating normal stiffness and shear stiffness in each pair of springs.
The sort modifications allow modeling cross sectional geometric parametersof structural members using elements with large size. The value of normal
and shear stiffness for each pair of springs can be determined as:
K ni

E * d * Tni
a

and

K

i
s

G * d * Tsia(1)where: d is the distance between each spring; a is the length of therepresentative area; E and G are Young’s and shear modules, respectively;
Tni and Tsi are the thickness represented by the pair of springs “i” for normal
and shear cases, respectively.
With these modifications, the total behavior of large-scale structures
under different hazardous loading conditions can be simulated with a good
accuracy and in a reasonable CPU time (Elkholy and Meguro, 2003;
122

New Technologies for Urban Safety of Mega Cities in Asia
70

ICUS Report 6

Elkholy and Meguro, 2004). The IAEM has been progressively developed
to carry out modeling the behavior of plane frame steel structures under fire.
3.0 CONSTITUTIVE MODEL OF STEEL UNDER FIRE
3.1 Material model
A simplified uniaxial bilinear stress-strain model with kinematic strain
hardening is adapted for representing the normal stiffness component ofstructural steel (Figure 1). In this model the plastic range remains constantthroughout the various loading stages, and the hardening rule for the yieldsurface is assumed as a linear function of the increment of plastic strain. The
model can be characterized by three parameters, the elastic modules (E),yield strength ( y), and straining of hardening parameter ( ). At increased
temperature, the material properties degrade and its capacity to deform
increases, which is measured by the reduction of the Young’s modulus.

Figure 1: Bilinear material model
3.2 Constitutive model
For heated and loaded steel, the constitutive model is described byassuming that the change inis expressed as the sum of three components,
as described in Equation (2) (Buchanan, 2001).
t

int

th

(t )

( ,T )

cr( ,T , t)(2)where:
is the total strain at time t,
is the initial strain at time t = 0,
int
is the thermal strain being a function only of temperature “T”,
th(T)is the stress-related strain, being a function of both the applied( ,T)stress “ ” and the temperature “T”, andis the creep strain, being a function of stress, temperature andcr ( ,T,t)time.
So far, the creep model for steel at elevated temperatures is not yet
included in the proposed numerical model. It has been assumed that thevariation of mechanical properties of steel with temperature takes into
account the creep effects.
tNumerical Modeling of Steel Structures in Fire Conditions Using Improved Applied Element Method
71

123

October 2004, Agra, India

4.0 THERMAL ANALYSIS BY USING IAEM
A step-by-step time integration procedure has been adopted to follow
the response of the structure subjected to elevated temperature. The flow
chart of the analysis in elastic loading condition is shown in Figure 2. For
convenience of analysis, the following hypotheses are employed:

Start
Apply static load
Apply time increment
Evaluate temperature temperaturetime curve
Calculate thermal elongation
Update material properties
according to selected design code
Repeatfor allCalculate stiffness of each spring
Calculate the thermal load vector

Main
procedureCalculate the residual force due tothe variation in material
Apply timeincrement

Assemble the calculated spring
matrix in the global stiffness
Calculate load vector
Solve the equations to get thedisplacement
Calculate strain components(thermal and mechanical strains)
Draw deformed shapeEnd
Figure 2: Flow chart of the program

Update the temperature profile through a given structure. The
temperature {Ti} at time ti is calculated at each spring location according
to the selected fire scenario.
Calculate the thermal elongation ( th) due to the temperature
increment.
Update the material properties (Young’s modulus (E), initial yieldstrength ( y) and strain hardening parameter ( )) of all springs when
the temperature of the structure is increased from {Ti-1} to {Ti}.
Create the new stiffness matrix of the structure considering thevariation of material parameters at each spring due to the rising oftemperature.
124

New Technologies for Urban Safety of Mega Cities in Asia
72

ICUS Report 6

Calculate the thermal load vector of each element {FTi} due to thetemperature increment { T } {Ti } {Ti 1} . For each spring, thethermal load is calculated according to Equation (3) and applied as acompression force applied at the elements’ boundary.
Fni

K ni ( th (Ti )th(Ti 1 ))

(3)

where K ni is the normal stiffness of spring i.
After calculating the thermal load vector, the general equation of
motion in case of thermal analysis is changed to be:

M

U

C

U

K

U

f(t) R m

RG

F (T )(4)

where: [M] is mass matrix; [C] is the damping matrix; [K] is thenonlinear stiffness matrix; F(T) is the incremental applied thermalload vector; { U},{ U},{ U} and {ΔU } are the incremental acceleration,
velocity, acceleration, and gravity acceleration vectors, respectively.
The value of the geometrical residuals around each element (RG) incase of dynamic load condition is calculated according to Equation(5) (Meguro and Tagel-din, 2002).
G

RG

F (T ) - M

U - C

U -Fm

(5)

where Fm is the element force vector from the surrounding springsof each element
Solve the equation of motion. Calculate the incremental and total
displacement vectors and obtain the total strain at each spring.
Subtract thermally induced strains ( th) from total strains ( t) toobtain the mechanical strains ( m) at each spring.
Assuming the stress-induced incremental strain is elastic, calculate
the current stress.
E( t

th

p0

)

(6)

If the stress obtained in the above step exceeds the tensile or thecompressive yield strength then recalculate the stress according to
the inelastic rule given by:
E( t

th

) (1

)

y

(7)

Calculate the geometrical residuals around each element from theequation below.
Apply again a new time increment and repeat the whole procedure.
The most important feature in this technique is that it allows evaluatedtemperature analysis beyond instability. Moreover, it takes into account the
dynamic effects, which can either add to destabilizing forces or delay themor both.

Numerical Modeling of Steel Structures in Fire Conditions Using Improved Applied Element Method73

125

October 2004, Agra, India

5.0 ILLUSTRATIVE EXAMPLES
To evaluate the capability of IAEM in modeling a steel structure
under fire, a comparison was conducted between the numerical model andthe results obtained experimental works.
A 5.50 m span beam of 305 x 165 UB 40 kg m-1 cross-section and
Grade 43 steel was loaded equally at the quarter points, as shown in Figure
3. The beam has flange slender ratio bf/tf = 16.18 and a web slender ratio ofh/tw =50.5. Firstly, the beam was loaded with R = 0.6 where R is the load
ratios defined as the maximum bending moment of a simply supported beam
to the plastic bending moment capacity of the beam at ambient temperatureaccording to BS5950: Part 8. After fully applying the vertical loads, thebeam is uniformly heated. Two support conditions had been considered in
the analysis as shown in Figure3:
Case 1: Pin – Roller support conditions
Case 2: Fixed –Slide support conditions
To model the steel properties at elevated temperatures, the bilinear
material model is employed with reduction factors shown in Figure 4. The
straining of hardening is assumed to be zero at room temperature andincreases gradually up to its maximum value of 0.05 at 400 °C anddecreases again to be zero at 650 °C. Tri-linear models are assumed torepresent the variation of modulus of elasticity and strength of steel withtemperatures. These factors are chosen as a best fit the given momentrotation curve given by (Bailey, 1998).
The mid span deflections, plotted against temperature, are shown in
Figure 5 for the two boundary condition cases, together with the results
illustrated by Bailey (1998). It can be seen from the figures the wellagreement between the analytical modeling using IAEM and test results.
The high capability of IAEM of evaluation the critical temperature andfollowing the total behavior of the beam is demonstrated.
Figure 6 shows the failure mechanisms and the formation of theplastic zones for the heated beams. From the figure, In case of Pin – Roller
support beam since the beam was free expand, the bending moment along
the beam was only due to the imposed load and no axial load had been
generated. The beam failed due to the formation of one plastic hinge at the
mid-span. The figure shows the spread yielding sequences illustrated by thedark color. When the plastic zones develop, the beam has lost most of its
strength and the deflection increases greatly, pulling the roller support closer
to the pin support. This mode of failure is known as a runaway failure mode.
On the other hand, in case of Fixed –Slide support case the supportsof the beam started to yield first. Subsequently, a third plastic hinge isformed at the mid span of the beam due to increasing deflection caused byformation of plastic hinges at the beam supports. Moreover, the criticaltemperature that produces failure of the beam is higher that the in pin- roller
support case.

126

New Technologies for Urban Safety of Mega Cities in Asia
74

ICUS Report 6

Span Length =5.50 m
2
y20 = 275 N/mm
B

B

P

E20 = 205 kN/mm2
B

1.375

B

P

P = 44.928 kN

1.375

Load Ratio = 0.60

Support schematic for Pin – Rollercase

305 x165 x 40 UB

ections-Cross

Support schematic for Fixed –Slide
case

Figure 3: Beams configuration and loading
0.05

0.8

Hardening factor

Reduction Factor

1.0

0.6
Yield strength
0.4
0.2
Young’s Modulus
0

200

400
600
800
Temperature (°C)

1000

1200

Figure 4: Material properties at elevated temperatures
Mid-span displacement (m)0 .5 00 .4 00 .3 0IA E M C a s e 2

B a il e y 1 9 9 8 C a s e 2

IA E M C a s e 1

B a il e y 1 9 9 8 C a s e 1

0 .2 0

Pin-Roller case

Fixed –Slidecase

0 .1 00 .0 0
0

100

200

300

400

500

600

700

Te m pe r atur e (°C )Figure 5: Behavior of heated beams
Numerical Modeling of Steel Structures in Fire Conditions Using Improved Applied Element Method
75

127

October 2004, Agra, India
P

P

P

P

P

Temp=297°C

P

Temp=540.0 °C
Temp=588.5°C

Temp=365°C

Temp=602.0°C

Temp=399°C

Temp=620.0°C
Temp=465°C

Temp=653.0°C

Temp=560.5°C
Temp=663.0°C

Temp=588.5°C

Temp=671.0°C

Figure 6: Failure mechanism of the heated beams
6.0 RESPONSE OF STEEL FRAME STRUCTURE TO A SUDDENFAILURE OF A COLUMN
Progressive failure is a principal cause of injury and death inbuilding failures regardless the source of the loading. Therefore, predicting
and designing to prevent the progressive failure. By using IAEM with thesame thermal analysis procedure, it is possible to evaluate the possibility of
progressive collapse of multi-story steel frame structures due to a sudden
failure in one of their supporting member.
The structure considered is a plane nine-story steel frame withthree bays of 9.00m long. The typical story height is 3.75m. The dimensionsof structure and that of structural members are illustrated in (Elkholy and
Meguro, 2004). Using IAEM, only 477 elements are utilized for modelingthe whole structure. In this paper, two cases of failure are introduced: failure
due to exterior and interior columns (Figures 7 and 8). At first, the design
load on the structure is applied as an initial load, while the sudden failure of
one supporting structural element is applied as loading in time domain. The
sudden failure of the structural members is modeled using a localized fire128

New Technologies for Urban Safety of Mega Cities in Asia
76

ICUS Report 6

scenario which produces reduction of the yield stress and Young’s modulus
to be 10% of their original values during a period of 0.10 second.

1.05 S1.40 S1.80 S2.20 S3.20 S

4.00 S

5.00 S

7.00 S

Figure 7: Progressive collapse due to sudden failure of exterior column

0.50 S1.45 S2.20 S2.60 S5.20 S

7.60 S8.20 S9.00 S

Figure 8: Failure mechanism due to sudden failure of exterior column
The figures show the entire collapse procedures and illustrate thehigh capability of following the trace of yielding and deformation at eachstructural member. The dark areas in the figures identify the zones that haveplastic deformations. The sudden removal of the column causes also
releasing of some of the potential energy and rapid alternation of internal
Numerical Modeling of Steel Structures in Fire Conditions Using Improved Applied Element Method
77

129

October 2004, Agra, India

dynamic forces. The simulation shows that the lack of joint ductility may
lead to a total collapse of the outer bay of the structure.
7.0 CONCLUSIONSIn this paper, a pioneering attempt to implement the thermal analysis
in the filed of Discreet Element based approaches is presented. The IAEM
has been progressively developed to carry out modeling the behavior ofplane frame steel structures under fire. The paper presents the methodology
and basic formulations of a new approach for thermal analysis to analyze
the large deflection behavior of steel structures at elevated temperatures.
The most important feature in this technique is that it allows evaluatedtemperature analysis beyond instability. Moreover, it takes into account the
dynamic effects, which can either add to destabilizing forces or delay themor both. The method can also follow the immediate geometric change in a
structure due to sudden removal of any element in the structure. Releasingof potential energy and rapid alteration of internal forces can be simulated
by using the direct step-by-step integration method technique used in IAEM.
REFERENCES
Bailey, C.G., 1998. Development of Computer Software to Simulate theStructural Behavior of Steel-Framed Buildings in Fire. Computer andStructures 67, 421-438.
British Standard Institute, 1990. BS 5950, Part 8, Code of Practice for theFire Protection of Structural Steelwork.
Buchanan, A.H., 2001. Structural Design for Fire Safety. John Wiley &Sons, West Sussex, England.
Cheng, W.C. and Mak, C.K., 1975. Computer Analysis of Steel Frame inFire. Journal of the Structural Division 101, 855-867.
Elkholy, S. and Meguro, K., 2003. Structural Failure Simulation due to Fireby Applied Element Method. JCOSSAR2003, The 5th Japan Conferenceon Structural Safety and Reliability, Tokyo, Japan.
Elkholy, S. and Meguro, K., 2004. Numerical Simulation of High-rise Steel
Buildings using Improved Applied Element Method. 13th World
Conference on Earthquake Engineering, Vancouver, Paper No. 930.
Meguro, k. and Tagel-Din, H., 2001. Applied Element Simulation of RC
Structures under Cyclic Loading. Journal of Structural Engineering,
ASCE 127 (11), 1295-1305.
Meguro, K. and Tagel-din, H., 2002. Applied Element Method used forLarge Displacement Structural Analysis. Journal of Natural Disaster
Science 24(1), 25-34.
Vimonsatit, V., Tan, K. and Ting, S., 2003. Nonlinear Elastoplastic
Analysis of Semirigid Steel Frames at Elevated Temperature: MP
Approach. Journal of Structural Engineering 129(5), 661–671.
Wong, M. B., Ghojel, J. I., and Crozier, D. A., 1998. Temperature-time
Analysis for Steel Structures under Fire Conditions. Struct. Eng. Mech.
6(3), 275-289.

130

New Technologies for Urban Safety of Mega Cities in Asia
78

WATER SCREEN FIRE DISASTER
PREVENTION SYSTEMCHARACTERISTICS OF WATER SCREEN
AS PARTITIONING TECHNOLOGY
5(,.2$0$12, YOUICHI IZUSHI, HITOSHI KURIOKA, HIDEAKI KUWANA, TAKASHI TSURUDA, TAKESHI SUZUKI
AND YOSHIO OGAWA3

University of Tokyo Visiting Professor, Kajima Corporation, Tokyo, JapanKajima Corporation, Tokyo, Japan
National Research Institute of Fire and Disaster, Tokyo, Japan
amanor@kajima.com
ABSTRACTWith the enforcement of the Special Measures Act for Public Use of
Deep Underground as well as with ongoing urban renewal, there is a needfor fire disaster prevention technology to secure the occupants’ safety incase of fire breaking-out in any underground space.
In this respect, a fire disaster prevention system using a water screen
was developed for potential fires in underground spaces. This system isaimed at securing the occupants’ integrity from the fire by partitioning thefire zone using a water screen and also at the safety of a structure by
reducing damage due to the fire. It would correspond to the performancebased-design for providing refuge for the occupants.
In the paper to be prepared, results obtained from experiments on thecharacteristics of the water screen when used as partitioning technology
will be described.
1.0 INTRODUCTION
With the enforcement of the Special Measures Act for Public Use of
Deep Underground as well as with ongoing urban renewal, there is a needfor fire disaster prevention technology in the case of a fire breaking out inany underground space or in tunnels.
With regard to this, a fire disaster prevention system using water
screens was developed. The aim of this system is to secure the occupants’safety from the fire by partitioning the fire zone using water screens(hereafter referred to as WS). This technology creates water screens byspraying water with a droplet diameter of about 200μm out of nozzles
arranged in a line for the partitioning.

103
79

October 2004, Agra, India
In order to understand the partitioning effects of the WS in the case ofa fire, fire tests were carried out in a road tunnel. The results of the first fire
test using n-heptane mixed with 5% toluene as the origin of a fire havealready been reported on.
In this paper, the details and results of a second test using gasoline as
the origin of a fire are described.
2.0 TEST OUTLINE
2.1 Aim of test
This experiment aims at understanding the formation of the WS
including their installation angle as well as the characteristics of the WS for
isolating the origin of a fire in the case of the wind speed being controlled at
2m/sec by ventilators during a fire in a road tunnel with a verticalventilation system. The other purpose is to investigate whether or not thepartitioned environment can allow the occupants to survive in the case of afire breaking out.
2.2 Experiment facility and model
The experiments were carried out at the overall fire test facility. The
large area used for the experiments was 25m high, 25m wide and 120m long.
Smoke was introduced through 12 ports at a rate of 2000m3/min in total.
The model shown in Photo.1 was scaled down to 1/2 the size of atunnel with the AA rank in the first class category for road standards. The
model, composed of steel frames and fireproof panels, was a box with aheight of 2.7m, a breadth of 5.4m and a length of 18.2m. On the sides of themodel, fireproof glass windows were installed at 3 locations for theobservation of the progress of the fire and the WS in operation.

Photo 1: Entire view of the modelNozzles for the WS were arranged in two parallel lines which wereabout 1.6m apart from each other and formed the partition boundary in thevicinity of both of the end openings of the model. 5 or 6 nozzles were fixed

104

New Technologies for Urban Safety of Mega Cities in Asia
80

ICUS Report 6in a zigzag pattern in each line at 1.0m intervals. The total amount of water
sprayed from the 11 nozzles installed on each side was 110L/min.
Smoke exhaust ducts and fans were installed at both of the end
openings and in the center of the model.
2.3 Establishment of fire origin
Ordinary passenger cars were assumed as the origin of the fire in twocases, one of a single car and the other of 3 or 4, and the heat release rate forthe combustion scale was set at 1.5MW and 5.0Mw respectively withconsideration to the reduced scale ratio. A fire plate with a diameter of
1,000mm and a height of 200mm was placed at the center of the floor of themodel in order to burn gasoline over a period of 10 minutes. The WS began
to work 30 seconds after igniting the gasoline.
2.4 Measurement points
2.4.1 Temperature distribution on the inside and outside of partitioned
area
The atmospheric temperatures of the inside and outside of the firezone which are partitioned from the fire using the WS were measured using
sheath type thermocouples. The thermocouples were installed at 200mm
intervals on the inside and outside of the partitioned area respectively andsuspended 50mm below the surface of the ceiling. Fig.1 shows themeasurement locations.
&2 濃度測定位置

Location for CO concentration measurements
温度･湿度測定位置


温度測定位置 熱電対 thermocouple●

Location for temperature・humidity
measurements
模型



ＷＳ

ｍ





Origin of a fire
火源




ＷＳ




ｍ

ｍ

●

ｍ


ｍ


ｍ


ｍ


ｍ

Figure 1: Measurement equipment installation in vertical section of themodel
2.4.2 Smoke concentration in the experiment facility
Figure 2 shows the locations where smoke concentration gauges
were installed. The concentration of the smoke which filled the experimentarea after rising up from the model was measured in the case of the WS
being used and in the case when it was not used. The light concentration
value was also measured using concentration gauges with photoelectric
separating type sensors installed in vertical and horizontal directions (with aheight of 9.9m~22.5m) at the ends of the experiment areas.

Water Screen Fire Disaster Prevention System-Characteristics of…
81105

October 2004, Agra, India
Gaugefor smoke
concentration

Experiment
facility
ｍ

ｍ

ｍ

1/2 scale model

Figure 2: Measurement equipment installation in vertical section of theexperiment facility
2.4.3 CO concentration on the outside of the partitioned area
The difference in the CO concentration of the smoke sampled bysmoke exhaust ducts and fans installed at both openings of the model
between in the case of the WS being used and in the case when it was not
used was measured using CO concentration gauges. The measurement
locations are shown in Fig.1.
2.4.4 Temperature and humidity on the inside of the partitioned area
The temperature and humidity with regard to the height of a humanbody (1.2m from the floor surface) in the case when the partitioned area wasformed using the WS were measured using gauges for temperature andhumidity installed halfway between the origin of the fire and the WS (6.3mfrom the center of the model). Fig.1 shows the locations of these gauges.
2.4.5 Spray distribution of the WS
Several fans for industrial use were installed at one opening of themodel in order to create a wind in the tunnel. For the purpose ofunderstanding the formation of the WS caused by the presence of windspeed, the water spray distribution was calculated from the amount of watercollecting in each of 25cm square measuring devices which were spread allover the floor in the vicinity of the WS.
3.0 TEST RESULTS
3.1 Temperature distribution on the inside and outside of the WS
Figs.3~6 illustrate the results of the atmospheric temperature
measurements carried out on the inside and outside of the WS in the case of
the WS being used. Figs.3 and 5 indicate the measurement results under adead calm. Figs.4 and 6 indicate the results in the case of the wind speed

106

New Technologies for Urban Safety of Mega Cities in Asia
82

ICUS Report 6being 1.4m/s. The wind speed described in this paper is set withconsideration to the reduced scale ratio and it corresponds to 2.0m/s in thecase of converting it into the actual scale.
As can be seen in Figs.3 and 4, in the case of 1.5MW for the heatrelease rate, there was smoke in the proximity of the ceiling surface in thefire zone partitioned by the WS and the temperature in this area climbed up.
The temperature in the vicinity of the ceiling on the outside of the WS fell.
It can be seen from Fig.3 that under a dead calm the temperature on theoutside of the WS dropped by 74% of the temperature in the vicinity of theceiling surface. Fig.4 illustrates that the temperature under windy conditions
dropped by 68% near the ceiling surface.
In the case of 5.0MW, it was discernible that the temperature fell by
79% under a dead calm as shown in Fig.5 and by 85% under windy
conditions as shown in Fig.6 respectively.

測定高さ [m]Height of Measurement (m)It was confirmed from the above that the temperature of the air andsmoke in the proximity of the ceiling surface was reduced by 70~80% dueto the use of the WS regardless of the existence of wind.
2.7
2.4
2.1
1.8
1.5
1.2
0.9
0.6
0.3
0
0

20

40

60

80

Inside of WS 
WS内Outside of WS
WS外[℃]
100 120 140 160

Height of Measurement (m)Figure 3: Temperature distribution on the inside and outside of WS(No wind 1.5MW)
2.7
2.4
2.1
1.8
1.5
1.2
0.9
0.6
0.3
0
0

20

40

60

80

Inside of WS 
WS内Outside of WS
WS外[℃]
100 120 140 160

Figure 4: Temperature distribution on the inside and outside of WS(wind speed 1.4m/s, 1.5MW)

Water Screen Fire Disaster Prevention System-Characteristics of…
83

107

October 2004, Agra, India
Height of Measurement (m)



2.7
2.4
2.1
1.8
1.5
1.2
0.9
0.6
0.3
0.0

[℃]

0

20

40

60

80

100

120

140

160

180

200

220

240

測定高さ [m]Height of Measurement (m)Figure 5: Temperature distribution on the inside and outside of WS(No wind 5.0MW)

2.7
2.4
2.1
1.8
1.5
1.2
0.9
0.6
0.3
0.0
0

20

40

60

80 100 120 140 160 180 200 220 240 [℃]

Figure 6: Temperature distribution on the inside and outside of WS(Wind speed 1.4m/s, 5.0MW)
3.2 Smoke concentration measurement results
Fig.7 illustrates the time history of the measured values for the smoke
concentration obtained in the test facility in the case of 1.5MW. Whenassuming that the value obtained by integrating the measured value using
the time axis corresponds to the total amount of the smoke flowing out of
the model into the test facility, the temperature was reduced by 78% under adead calm when the WS was used in the case of 1.5MW. When the windspeed was 1.4m/s, the temperature was reduced by 60% of the value in thecase of the WS not being used. It was confirmed from the above thatregardless of the existence of wind, 60~80% of the smoke rising from theorigin of the fire was isolated by using the WS.
3.3 CO concentration measurement results on the outside of thepartitioning area
The maximum value for CO concentration obtained by analyzing thesmoke rising from the fire origin, collected at the ceiling of the opening of
the model, in both cases of the WS being used and not being used was
reduced by about 15% under a dead calm in the case of 1.5MW and was

108

New Technologies for Urban Safety of Mega Cities in Asia
84

ICUS Report 6

Light reduction coefficientTime ( Sec)

Figure 7: Time history graph of smoke concentration in the experiment
Facility.
reduced by about 45% when the wind speed was 1.4m/s. It was thought thatthe fact that the temperature fell only 15% under a dead calm was caused by
CO which is insoluble in water instead of the partitioning of the WS. It canbe thought that the great decrease in the CO concentration in the case of
1.4m/s was caused by the incomplete collection of the smoke at the openingof the model due to the effects of the wind. Therefore, the reduction ratio of
the CO concentration in the outside of the area partitioned using the WS was
set at about 15%.
3.4 Temperature and humidity measurement results on the inside of thepartitioned area
It was confirmed that the temperature as well as the humidity on theoutside of the partitioned area while the WS was used did not reach thecondition that is critical for human life. (Human bodies are exposed to thecritical condition in 5 minutes when the humidity is 100% and thetemperature is 50℃ or more according to field guide to fires) the humidity
rose to 100%, but the temperature was 20 ℃ which was the exteriortemperature. The maximum recorded temperature was 35℃.
3.5 WS Spray distribution measurement results
With regard to the water spray distribution of the WS under a deadcalm, the maximum value for the spraying amount was seen at the center ofthe WS nozzle. (See Fig.8) In the case of the wind speed being 1.4m/s, thelocation for the maximum value of the spraying amount shifted to a point of
1.8m on the leeward from the center of the WS nozzle. (See Fig.9) It was
confirmed from the above that the spraying angle was 33°. Furthermore, it
was discernible from the eye measurement that in the case of 1.4m/s for thewind speed, the water screen was formed extending from the ceiling surface
down to the floor surface.

Water Screen Fire Disaster Prevention System-Characteristics of…
85

109

October 2004, Agra, India
ＷＳ中心位置Centerof the WS

12.7m

2.7m

θ＝0゜

散水量最大値
Maximum
value for water spraying amount
15000

10000



模型高さ

散水量 [mL/min]

20000



5000

0
11.0

12.7m

12.0

14.0

15.0

16.0

17.0

19.0

火源からの距離X[m] the fire origin (m)Distance from

Figure 8: Water spraying graph (no wind)Center of the WS
ＷＳ中心位置
12.7m

風

12.7m

θ

1.8m

10000





模型高さ

Wind

散水量 [mL/min]-1

θ＝tan (1.8 / 2.7)
＝33゜

15000

2.7m

散水量最大値
Maximum
value for water spraying amount

20000

5000

0
11.0

12.0

14.0

15.0

16.0

17.0

19.0

火源からの距離X[m]the fire origin (m)Distancefrom

Figure 9: Water spraying graph (wind speed 1.4m/s)
4.0 CONCLUSIONSAs for the characteristics of the WS for the partitioning of a firezone, it was confirmed that the isolation effects for heat, smoke
and poisonous gas (CO) were 70~80%, 60~80% and 15%
respectively.
It was discernible that in the case of the wind speed being 1.4m/s(the wind speed converted to that on an actual scale: 2.0m/s), theWS was formed at an angle of 33o where the same effects wererecognized.
It was also confirmed that the occupants could survive in the firezone partitioned using the WS and that activities for refuge andfire fighting could be effectively carried out.

As a result, the validity of the WS as partitioning technology for a fire
was verified.
ACKNOWLEDGEMENT
We would like to express our thanks to the staff concerned of the
HOCHIKI Corporation who gave us a great deal of cooperation for theexperiments and analyses.
REFERENCES
Reiko Amano, Yoichi Izushi, Hitoshi Kurioka, Hiroomi Sato, Hideaki Kuwa
na,Takashi Tsuruda, Yoshio Ogawa, Takeshi, 2004. Water Screen Fire
Disaster Prevention System in Underground Space. 6th Asia-Oceania
Symposium on Fire Science and Technology, Soal [1].

110

New Technologies for Urban Safety of Mega Cities in Asia
86

URBAN FLOOD MODELING IN LOWER
MEKONG BASIN: A PHYSICALLY BASED
DISTRIBUTED MODELING APPROACH
D. DUTTA1,2, M.J. ALAM1 AND S. HIRONAKA3
1
RNUS, SCE, Asian Institute of Technology, Thailand
2
ICUS, IIS, University of Tokyo, Japan
3
NEWJEC Inc., Tokyo, Japanddutta@ait.ac.th
ABSTRACTThis paper presents the results of an application of a distributed modelin the lower Mekong River basin for flood inundation analysis. The
distributed hydrological model is a combined surface-river flow model
which solves the one-dimensional (1-D) unsteady flow equation for river
channel flow and two-dimensional (2-D) flow equation for each grid of thefloodplain simultaneously to calculate the flood inundation parameters inthe basin. The calculations of flow from river channel to flood area causedby flood levee failure or overtopping of levee, flow from flood area to river
channel such as sluice, pump etc., moreover, condition of basin or river
channel, are done by using some suitable equations in conditions. The study
area is the Cambodian floodplains of the Mekong River. In preliminary, thesimulation has been carried out for the flooding condition of 2000. The
simulated flow along the major rivers show close agreement with theobservations. The results from the model application are presented here.
1.0 INTRODUCTION
The Mekong basin, one of the important and largest river basins in theworld, originates in the highland of Tibet in China and ends in the South
China Sea comprising the territories of six Southeast Asian countries- China,
Myanmar, Lao PDR, Thailand, Cambodia and Vietnam. The drainage areaof the basin is 795,000 km2 with a total length of 4,620 km (Hori, 2000).
The Lower Mekong basin covers 78% of the total basin area which includes
four riparian countries of the region: Laos, Thailand, Cambodia andVietnam (Figure 1).
The flooding in the Mekong basin, a very common phenomenon
occurring several times a year, greatly varies in magnitude and extent indifferent parts due to spatial variability and local hydro meteorologicalcharacteristics including rainfall distribution. In the lower reaches of
Cambodia, where the land is low and flat, a larger area is usually inundated.
In 2000 during the period of August-November, the Lower Mekong region
observed a record breaking flood in Cambodia and Vietnam estimating
about 600 casualties, over 300,000 evacuated people and altogether withhighest recorded water level in Phnom Penh since records began (Dutta,
2000). The reasons for the recent year’s floods are reportedly due to14187

October 2004, Agra, India
deforestation, reclaiming of land, urban expansion and the decrease ofnatural channels for the basin development (Kazama, et al., 2001). The
frequency of flooding is also increased in the lower part.

Figure1: Location map of study area

The flood modeling in the Mekong was first initiated in the decade of1960 with a view to an establishment of a basin wide flood warning system
for the alleviation of adverse effect of floods in the areas along the MekongRiver and the Delta (Dutta and Herath, 2001). After the development of aflood forecasting system through UNDP program in 1970, the floodmodeling has got a momentum to continue in different forms from simple
black box or conceptual modeling to complex hydrodynamic system byvarious organizations. With the rapid progress in computational resources,
there have been tremendous development in modeling approaches over theworld, and some of these approaches have also been applied in Mekong
Basin. A geomorphology based distributed hydrological model was applied
to the upper central part of Mekong River basin, from Luong Prabang
station at the boarder of China up to the Stung Treng gauging station in
Cambodia, covering an extent of 402,636 km2 as an initial study on
distributed hydrological simulation in Mekong river basin (Herath et al.,2000). To evaluate multi-functional hydrologic role, a hydrologic model
was applied to Tonle Sap and its vicinities (Masumoto, 2000). Onedimensional modeling along with 2-d model in Chaktomouk junction of
Mekong River was carried out within the present study area in connection
with morphological study (Olesen, 2000). Although, a great progress offlood modeling in Mekong River basin could be seen, there is still need of
improvement in the existing approaches. Another limitation is that data
availability and integration in the model development.

142

New Technologies for Urban Safety of Mega Cities in Asia
88

ICUS Report 6In this research, the Cambodian flood plain of the Mekong river, Tonle
Sap Channel and Bassak river is selected as study area for modeling. Theselower reaches of the Mekong River (below Kratie) have different hydrologic
and hydraulic characteristics than the rest of the Mekong basin. The flow
patterns in these portions of the basin are characterized by very low water
surface slopes, inundation of a huge floodplain during and after the annual
flood peak, and deposition of a fraction of the suspended sediment on theriver dykes and adjacent floodplains (MRC, 2003).
2.0 MODELING APPROACH
2.1 Outline of the model
The distributed model used in this study is a coupled surface-river
flow model, which has been designed to calculate the flow parameters in theriver channel and floodplain simultaneously. The model was originallydeveloped by the Public Work Research Institute (PWRI), Japan (Yoshimoto
et al., 1992). The main characteristic of the model is the link between
unsteady calculation in river channel and calculation of flood depth in river
basin to reproduce the flood inundation phenomenon in large scale over thewhole river system. The relation between stage in river channel and heightof levee decides the points and scale of flood levee failure with unsteadycalculation in river channel. A schematic diagram of the model is shown in
Figure 2.
Flood levee failure(Ht, Qt Relation)

Calculates flow and waterlevel at each cross section in
every time step (∆T)

Calculates flow and depth
in every ∆T

Figure 2: Outline of the model (adapted from Yoshimoto et al., 1992)



2.2 Governing equations
Basically, the model uses two dimensional unsteady flow equations forflood flow calculation in basin, and one dimensional unsteady equation forriver flow. However, outside of these, flow from river channel to flood area
caused by flood levee failure or over flow of levee, flow from flood area toriver channel such as sluice, pump etc., moreover, condition of basin or
river channel, in some cases these equations are not applicable, where somesuitable equations are used in conditions. For example, in case of calculation
about flood plain, local phenomena which is unable to solve with energy

Urban Flood Modeling in Lower Mekong Basin: A Physically Based Distributed Modeling Approach89

143

October 2004, Agra, Indiaequation as long as not using empirical coefficient occurred at the points
where gradient of flood plain changes suddenly except the effects due toweir of bank, calculation is done using other equations as discussed in thesections below (Yoshimoto et al., 1992). Besides, model uses empiricalequation for calculation of flow in box culvert or over banking flow whenembankment exists on the flood plain. The unsteady equations are derived
from continuity and momentum equations for one dimensional as well as fortwo dimensional flows.
2.3 Model setup
2.3.1 River systemFor preliminary simulation, a small part of river system near Phnom
Penh city has been considered which includes Mekong River (Below
Kompong Cham), Bassak River and Tonle Sap Channel as shown in Figure
3 with hydrological gauging stations. The river setup has been assigned withcross sections. The raw cross sections data have been processed and given
as H-B-A-R (Height-Width-Area- Hydraulic Radius) relation in the model.
The details of cross-section of the the river system are given in Table 1.

Figure 3: Model River Network
In river cross sections the link between the 2-D grids of the flood plain
and the river channel is specified. The relation between stage in river
channel and height of levee decide the points and scale of flood levee failure
with unsteady calculation.
Table 1: Details of Model Rivers
RiversU/s locations

MekongBassakTonle Sap

Kompong Cham
Mekong Ch.213.0 km
Mekong Ch.213.0 km

144

D/s

location

Tan Chau
Chau Doc
Prek Kdam

No. of cross sections
84
32
38

New Technologies for Urban Safety of Mega Cities in Asia
90

ICUS Report 6
2.3.2 Model grid
Rectangular grid of 1 km resolution has been used in this study. The
total number of grids within the study area is 121113. The source of theDigital Elevation Model (DEM) is the Mekong River Commission
Secretariat (MRCS), which has originally been derived from various sources
data (Figure 4).

N
Model River
Primary Area
Secondary Area

iv

er

gR

R i ve r

Me
ko n

ap
nle S
To

Elevation (m)-9 - 910 - 29
30 - 49
50 - 99
100 - 199
200 - 499
500 - 999
1000 - 1499
>1500

M
ek

o ng

40

er

0

Ri v

iver
B as s a k R

40

80 KilometersFigure 4: DEM of the Model Area (Source: MRCS)
2.3.3 Structures and other information
The model has the provision of incorporating hydraulic structures likeweir, culvert and pumping options for drainage and retarding basin. The
embankment or road alignment along with structures information gives thetrue description of the physical system. However, not all of theseinformation are incorporated properly yet in this simulation, which are being
updated from the available source for final calibration of the model.
2.4 Model application
The model has been applied for simulation of flooding during theperiod of 1st of July to 31st October of 2000. The stability of simulation isvery much dependent on grid spacing and the time step used in computation.
In use of 1 hour time step, stable simulation has been obtained. Rainfall has
been specified as an internal runoff on the model grid. Evaporation value
has been deducted from daily rainfall value to calculate the net rainfall.
Based on the Thiessen polygon developed for the project area, rainfall has
been distributed over the grid as internal runoff (m3/s). At 46 locations therainfall data is available for 2000 and evaporation data available only in one
station at the MRCS Headquarter. The average of daily rainfall of 46
stations is shown in Fig. 5.

Urban Flood Modeling in Lower Mekong Basin: A Physically Based Distributed Modeling Approach
91

145

October 2004, Agra, India
2.4.1 Initial and boundary conditions
The initial water level in the river channels has been specified basedon observed data. However, the flood plain has been considered dry at
initial time step. The time series boundary data has mainly been obtained
from the project of Consolidation of Hydro-Meteorological Data and MultiFunctional Hydrologic Roles of Tonle Sap Lake and Its Vicinities(Basinwide) (MRC, 2003). At the upstream of Mekong River a time seriesof daily discharge has been provided as an inflow. The discharge data has
been generated based on a rating curve developed by 2002 observed data.
The inflow boundary is shown in Fig. 6. At the down stream boundary
locations daily observed time series water level data has been specified.
Boundaries of the flood plain grid have been assumed closed, i.e. no flow isgoing out or coming into the basin through the boundary meshes.

01
-J
ul
-0
0
15
-J
ul
-0
0
29
-J
ul
-0
0
12
-A
ug
-0
0
26
-A
ug
-0
0
09
-S
ep
-0
0
23
-S
ep
-0
0
07
-O
ct
-0
0
21
-O
ct
-0
0

Rainfall (mm)

40
35
30
25
20
15
10
5
0



Figure 5: Average of daily rainfall of 46 stations around the study area
Rated Discharge in Mekong River
Station: Kompong Cham
60000

Discharge (m3/s)

55000
50000
45000
40000
35000
30000
25000
20000
07/01/00

07/21/00

08/10/00

08/30/00

09/19/00

10/09/00

10/29/00

Figure 6: Inflow boundary to the upstream of Mekong River146

New Technologies for Urban Safety of Mega Cities in Asia
92

ICUS Report 6
2.4.2 Roughness coefficient
A fixed value of Manning roughness coefficient has been specified ineach cross section of river channels. The roughness value for river channels
is 0.03. For the flood plain grid the roughness value has been used based on
the land use type. The landuse map of 1km resolution for the study area was
obtained from Global mapping project. Besides, in roughness calculation,model also considers the occupied housing ratio in the each grid of the flood
plain.
3.0 RESULTS AND DISCUSSIONSThe simulation results of river water levels for the period of July 1st to
October 31st of 2000 have been compared with the observed water levels at
different gauging stations along the four river branches in the study area. In
absence of any field observation, the simulated extents of flood inundation
have been compared with satellite imagery. Fig. 7 shows the comparison ofsimulated and observed daily water levels at the gauging stations of
Meklong river (Choroi Changvar and Neak Loung stations), Basak river(Koh Khel station) and Tonle Sap river (Phnom Penh Port station). The
locations of these gauging stations are shown Fig. 3. It can be observed fromthe comparison that the simulated water levels match well with observed
ones in Mekong and Basac Rivers. However, the simulated water level ismuch higher than observed water level at Phnom Penh Port in Tonle Sap
river. The Tone Sap lake in the upstream of this river influences the flow
characteristics greatly. For improvement of the simulated results, it will be
important to incorporate this lake in the simulation.
The simulated maximum flood inundation extents and depths of
September 20, 2000 are shown in Fig. 8. By comparing simulated
inundation map with the flood extent observed from the LANDSAT TM
image of September 26, 2000 (as shown Fig. 9), it can be noticed that thesimulated flood pattern and locations agree well with the actual flooding.
However, the simulated flood extent is much lesser than the observed flood
extent from the remote sensing image along the Mekong and Tone Sap
rivers. There are two major possible reasons for this. The first reason is thatin simulation there no consideration of flood water entering to the study areafrom outside over the ground, only inflow along the river system isconsidered as the upstream boundary conditions. However in reality, there isa large amount of water entered to the study area as overland flow. The
other possible reason is the low resolution of the DEM considered in themodel. Flood modeling is very sensitive to DEM, it is required to consider
high resolution topography dataset for obtaining better modeling outcomes.

Urban Flood Modeling in Lower Mekong Basin: A Physically Based Distributed Modeling Approach
93

147

October 2004, Agra, IndiaComparison of Water Level at Choroi Changvar
11.5
11Water Level (m)

10.5
10
9.5
9
8.5
8
7.5
7
1-Jul

31-Jul30-Aug29-SepObserved

29-OctSimulated

Comparison of Water Level at Neak Loung
8.5

Water Level (m)

8
7.5
7
6.5
6
5.5
5
1-Jul-00

31-Jul-00

30-Aug-00
Observed

29-Sep-00

29-Oct-00

Simulated

Comparison of Water Level at Koh Khel
8.5

Water Level (m)

8
7.5
7
6.5
6
5.5
5
1-Jul-00

31-Jul-00

30-Aug-00
Observed

29-Sep-00

29-Oct-00

Simulated

Water Level (m)Comparison of Water Level at Phnom Penh Port
11
10.5
10
9.5
9
8.5
8
7.5
7
6.5
6
1-Jul-00

21-Jul-00

10-Aug-00

30-Aug-00

Observed

19-Sep-00

9-Oct-00

29-Oct-00

Simulated

Figure 7: Comparison of simulated and observed water levels at thegauging stations Choroi Changvar, Neak Loung, Koh Khel,and Phnom Penh Port148

New Technologies for Urban Safety of Mega Cities in Asia
94

ICUS Report 6









Figure 8: Simulated maximum flood depths and extents

Figure 9: LANDSAT image on flood of 26 September 200
4.0 CONCLUSION
In this paper, a physically based distributed surface-river model has
been introduced and the results of flood inundation simulation in an urban
area in the lower Mekong basin have been presented. The simulated waterlevels along the Mekong and Basac rivers show close agreement with theobservation. However, the extent of simulated flood inundation is lesser
than that is observed from satellite data. It is required to improve thesimulated inundation with realistic consideration of inflow from outside andhigher resolution of DEM and the simulated flood inundation parameters in
different locations should be thoroughly verified with the groundobservation.

Urban Flood Modeling in Lower Mekong Basin: A Physically Based Distributed Modeling Approach95

149

October 2004, Agra, India
This is an on-going research project. In the next phase of simulation,
the study area will be extended to cover the Tonle Sap Lake, which has agreat influence in flood characteristics and flood inundation simulation will
be carried out with updated details of topography and surface boundary
conditions to consider the flow influx from outside of the study area.


REFERENCES
Chow, Ven Te, Maidment, David R., Mays, Larry W. 1988. Applied
Hydrology. McGraw-Hill, Inc., pp35.
Dutta, D. and S. Herath 2001. Flood Modelling Experiences in MekongRiver Basin. Proceedings of the International Symposium on
Achievements of IHP-V in Hydrological Research, Hanoi, Vietnam,
IHP-V Technical Document in Hydrology No. 8, pp.51-52.
Dutta, D. 2000. Devastating Floods in Cambodia, 2000. INCEDE
Newsletter. Vol. 9, No. 1, pp. 1-4.
Herath, S and Yang, D.2000. Distributed Hydrologic Modeling in Mekong
Basin. Proceedings of the workshop on Hydrologic and Environmental
Modelling in the Mekong Basin, 11-12 September 2000, Phnom Penh,
pp30.
Hori, H. 2000. The Mekong: Environment and Development. United Nations
University Press, Japan, ISBN: 92-808-0986-5, pp1.
Kazama, S., Hagiwara, T. and Sawamoto, M. 2001. Temporal and Spatial
Inundation Pattern Revealed by Numerical Simulation of the 2000 Floodin the Lower Mekong. Proceedings of the International Symposium on
Achievements of IHP in Hydrological Research, Hanoi, Viet Nam, 1922 November 2001, IHP-V Technical Document in Hydrology No.8,
International Hydrological Programme, UNESCO Jakarta Office.
Masumoto, T. 2000. Modelling of Multi-Functional Hydrologic Roles ofTonle Sap Lake and Its Vicinities. Proceedings of the workshop on
Hydrologic and Environmental Modelling in the Mekong Basin, 11-12
September 2000, Phnom Penh, pp181.
Mekong River Commission (MRC). 2003. Consolidation of HydroMeteorological Data and Multi-Functional Hydrologic Roles of Tonle
Sap Lake and Its Vicinities (Basinwide). Draft Final, Main Report, pp1-1.
Olesen, K. W. 2000. Morphological Modelling of the Chaktomuk Junction,
Proceedings of the workshop on Hydrologic and Environmental
Modelling in the Mekong Basin. 11-12 September 2000, Phnom Penh,
pp289.
Yoshimoto,T., Fueda, T., Ikeda, Y., Kawakami, T. 1992. Technical
Memorandum of Public Work Research Institute (PWRI). Flood
Simulation of Two Dimensional Unsteady Flood Model, Public Works
Research Institute, Japan , T. M. of PWRI No.3105, ISSN 0386-5878.
Geographical Survey Institute. 1997. Global Map’97 Dataset. Secretariat ofthe International Steering Committee for Global Mapping, Kitasato 1,
Tsukuba, Ibaraki, 305-0811, JAPAN.

150

New Technologies for Urban Safety of Mega Cities in Asia
96

HYDRAULICS COMPUTATIONS TOSTUDY FLOOD CONTROL FOR
HA NOI CITY,VIETNAM
TRAN THUC1 AND NGUYEN HUU PHUC2
Institute of Meteorology and Hydrology, Viet Nam
2
Department of Flood Control and Dike Management, Viet Nam
thuc@netnam.vn
1

ABSTRACT
Hydrodynamic model was applied for the Red River system, North
Viet Nam to evaluate the effectiveness of the existing flood control measuresin the river basin. Results of computations show that the current flood
control structures of the Red River basin cannot cope with extreme flood,water level at Ha Noi is still higher than the designed value. Emergency
spillways on the dike system were studied and it is found that they cansignificantly reduce water level at Ha Noi. With the use spillways, waterlevel at Ha Noi can be kept lower than the designed value when a 2000-year
return period flood occurred.
1.0 INTRODUCTION
The Red River system with a catchment area of about 143,000 km2 isthe biggest river system in North Vietnam. There are three main river
tributaries, namely, Da River, Thao River and Lo River. The Red Riversystem and its tributaries are shown in Fig. 1.
102°E

102.5°E

103°E

103.5°E

104°E

104.5°E

105°E

105.5°E

106°E

106.5°E

107°E

23°N

20°N


Figure 1: Red river system

63
97

October 2004, Agra, India
Strategy for flood prevention in Red river Delta is “actively preparing
for flooding”, including 6 basic measures: planting and protecting upstream
forest, flood regulation by reservoirs, dyke system, flood drainage, flood
diversion and detention.
Reforestation and watershed protection: The country has 19 million ha offorest land, but only about a half of the area is covered by forest, theremaining is covered by grass, bushes and scattering trees. Forest area isreduced very quickly due to shifting cultivation, irrational wood exploitation.
The Viet Nam Government has been implementing activities ofreforestation program in mountainous areas.
Dyke system: It is the main and most important measure. In the Red Riverdelta, there is a river dike system of 2,000 km in length to protect the urban
centers and the important economic zones. At present and in the future,dyke will remain the main and most effective flood prevention measure. In
general, dyke systems in the Red River basin can stand against designed
flood. However, it cannot cope with extreme flood, if a 1000-year return
period flood happened, dyke might break.
Flood regulation: Hoa Binh Reservoir is a large-scale reservoir built in1979 on the Da River, some 70 kilometers to the northwest of Ha Noi with a
total storage capacity of 9.45 billion m3. In the Da River water resources
development plan, a cascade of reservoirs will be built on the Da River,
upstream of Hoa Binh reservoir.
Flood diversion: Day River flood diversion is responsible to divert flood of
the Red River to Day River with a design discharge of 5,000 m3/s. However,
due to flood plain encroachment, some calculations have shown that atpresent, only about 3,000 m3/s can be diverted. The most difficult problems
for flood diversion in the Day River is that too many people (nearly
700,000) would now have to be resettled, and about 200 km of dykes need
to be more frequently repaired.
Flood detention: Four areas are reserved for flood detention: Tam Thanh
area (200 x 103 m3), Lap Thach area (100 x 103 m3), Luong Phu - Quang
Oai area (600 x 103 m3).
Flood drainage improvement: After the historical flood in 1971, measures
to improve flood drainage have been carried out. However, as dredging needa huge a mount of money, difficulty in funding has limited the result ofchannel improvement.
A lot of experiences have been gained in flood prevention,
preparedness. The Red River Delta still has a high potential threat offlooding. It is seen that current flood protection system is still insufficient tocope with extreme flood; more effective measures are needed for flood
control and management for the North Viet Nam.

64

New Technologies for Urban Safety of Mega Cities in Asia
98

ICUS Report 6


2.0 HYDRAULIC COMPUTATIONS TO DETERMINE
EMERGENCY SPILLWAY FOR DIKE SYSTEM
2.1 Computation scheme
HEC-RAS model is applied for hydraulic computations for the Red
River system. The computation scheme includes 25 river tributaries (Da,Thao , Lo, Hong, Cau, Thuong, Luc Nam, Duong, Thai Binh, Kinh Thay,
Kinh Mon, Lai Vu, Gua, Da Bach, Moi, Mia, Luoc, Lach Tray, Hoa, Tra Ly,
Dao Nam Dinh and Day rivers), and 792 cross-sections (Fig. 2).
Phó ThäTh¸c Huèng

Vô Quang

1

1

214

386

213
2

2

387

215

3

3

214

CÇu S¬n
433

386

433

387

434

388

434

388
216

4

389

215

4
5

390

216
6

6

218

391

217
7
7

392

219

8

8

218

9

219

393

220

9

394

10

221

10

220

11

435

389
217

5

395

390

435
436

391
436
392

437

393

437

394

Chó thÝch

438

S«ng Th-¬ng
438

395

439

222
439

221
223

440

Qu¶ng C-

222
224
223

biªn d-íiChòbiªn trªn

441

628

632
225

KiÕn An (H)

440

441

224
442
226

864

21
22

863

861

23

21

208 209 21026

211 212 213

30

31

32

33

34

35

36

37

445

587

28

29

30

31

32

33

34

35

36

37
38

S«ng §µ

446
635

633

634

639

638

446

632

447

636

637

597

39
40

449

40

449
41

Qu¶ng Oai

R21
BÊt B¹t

tªn mÆt c¾t

448
448

39

849
799

450

41

800

R22

S«ng Hång
42

848

42

451

Chò

451

43
846

464

44

452

44
635

tr¹m thuû v¨n

450

43

756

tªn ®o¹n s«ng

635
231
38

447

27

203

29

28

445

631

230
229

230

26

452

h-íng dßng ch¶y

464

45

756
757

465

45
465

46

S«ng Lôc Nam

56

845

757

nót « ruéng

444

228
23

27

207 208 209 210 211 212

807

444

634

229

24

204 205 206

201

443
443

630

227 22822

25

199 200

442

633
227

226

808
862

Hoµ177 178 179 180 181
B×nh 176 177 178 179 180

629

225

R24
Tam Thanh

47

758

466

47
129
48

48

759
49

843
49
760

50

798

50

761

467

S¬n T©y(H, Q)

467

455

468

455

51

850

Bèi
VÜnh T-êng

844
762

466

BÕn M¾m

468

51
52

469

456
851

R23 801

469

456

53

763

470
54

457
470
457

764

V©n Cèc

55

471
458

852

471

56

785

785

784

458
418

57

472

418

853
419

78

686

685

80

81

§¸p CÇu (H)

79

82

423

426
425

427
426

428
427

429
428

430
429

431
430

432 463431

Ph¶ L¹i

83
84

480

480
232

85

233

231 232

234

235

236

693

88
89

694
794

233 234

235

237

236

238

237

239

238

240

239

241

242

240 241Th-îng C¸t
(H,Q)

85
86

692
87

789

86

243

242

244

243

245

244

246

245

247
246

249

248
247 248

250

256

249

256

259

257

260

258

259

90

S«ng Kinh ThÇy

261

260

262
481

261

BÕn Hå

482
482

S«ng §uèng

526

527

525

528

526

527

529

S«ng Kinh ThÇy

530

528

531

529

532

530

531

483

558

485

558

699
96

543

489

95

606

489

606
607

607

98

560

133
491

608

491

702

616

560

704

494

777
811

611

496

563

612
497

709

497

710

498

564

564

622

612

498
793

794

R5

R6

795

796

622

547

Phó L-¬ng

817
818

621

563

708
815

621

547

611

496

132

812
810

620
620

546

610
562

495
707

783

562

495

706
131

782

781

619
618
619

561

494

130

805

779

618
617

546

561

705

804
806

776
778

616

545

610

493

129
133

615

609
493

132

775

617

545

609
492
492

703

801

803

544

608

134
800
131

544

BÕn TriÒu (H)S«ng Kinh M«n

490

97

543

559

S«ng Lai Vu

490

97

132
701

542
542

605
605

96

700

604

604
559

488

802

792

541

603
603

S«ng Th¸i B×nh
488

94

An Phô

602

487
487

93
94

130

540

601
601

486
92

129

539

540

602

95

R4 798

539
538

541
486

92

791

538

537

485

698

R2

537

536

An Bµi

600
600

89

93

697
796

797

867

599
599

484

90

808

834

536

535

534

557

484

88

91

696

809

535

534

533

BÕn B×nh

483

91

795

R1 790

533

532

598

C¸t Khª87

Hµ Néi (H,Q)

695

479

432
479

84
691

R3

Lôc Nam(H)

462
463

423 42483

R20 833

690

792
793

473

462

S«ng CÇu

422

81
82

855

791

788

474

461
421

421

80

424 425

688

788

474

475

422

802
856

787

475

476

461

79

R19

678

420

78

854

687

688
689

477

420

784
789

476

473
478

460

790

477

460

419

787

472

459
478

459

786

786

548

623

613

820

R8

R7 819

821

565

499

711

623

548

614

Qu¶ng §¹t

500

S«ng §¸
624 B¹ch
614

500

822

613

565

499
712

R9 797

566

624

566

824

713

501

823

R10 677

549

501
714

825

625

567

502

549

502

625

567
715

503
503

826

504

568
625

504

R13

625

550

568

716

832

833

550

717
505

827
718

505

719

506

829

830

720

831

721

676

Cao Kªnh 551(H) 551

569
569

828

S«ng Gïa

506

481

552

570

507
627

628

629

552

507

S«ng CÊm

570

Ngäc §iÓm587

B¸ Nha 571

508

588

508

586

627

Do Nghi (H)

553

587
553

722
509
723

509

724

510

588

571

Trung Trang

835

554
589

572

510
836

626

626

576

554

589

572

555
725

555
590

511
726

573

838

556

512

591
574

512

727

839

556
591

513
728

840

592

729

S«ng MÝa

514

842

514

129

593

593
576
594

131
131

659

737

660

738

S«ng L¹ch Tray

516

515

130
130

H-ng Thi

592

517

515

731

KiÕn An (H)

575
575

516

129

730

557

574

513

841

R12 674

590

573

511

837

R11 675

577

594

578

595

132
577

132

663

133
133

664
739

134

665 661

595

596

578

134
741

666 662

135

579

135

596
597

579
136 136
667

663

R15

664
668

804

R16

R17

R18

805

806

807

137

755
858

665

859

138

860

666

676
668 669

580

640

672

636

Gi¸n KhÈu

264

262 263

265

264

266

265

267

268

266 267

269

268

270

269

271

270

272

273

271 272

274

273

275

274

276

275

277

276

278

277

279

278

142

144
144
145

642
Ninh B×nh
646

292

294

293

295

294

296

295

581

615

297

296

630

Qói Cao

631 581KiÕn An (H)582TiÒn TiÕn 582

362
517

362

S«ng 583
V¨n óc

363

298

299

300

301

302

364

303

518

575

519

584

520

585

584

518

364
297

298

299

145
146

S«ng Hång
146

643

300

301

302
303

243

S«ng Th¸i B×nh

365QuyÕt ChiÕn 304

S«ng Ho¸

304

585

519

147

647

305

147
644

148

586

305

148
645

520

149

649

306

149
650

291

293

363
143 143640

645 641

648

290

142

639
643
644

292

361

T¶o Xu©n141 141

638
642

290

289

TriÒu D-¬ng

140 140

637
641

Chanh
Ch÷
291

138

139
139

597
598

137

263
673

660

580

H-ng Yªn

754

857

646

370

Quang Phôc(H)

370

306

521
371

647

385

384

383

380

381

382

651
648
385

384

383

382

380

381

379

307

378
377 150

378

379

372
309

153

373
522

373

309

374

309
154 154

523

374
310

155

375

155

523

310

156

653

522

372

308

152
152
153

649

521

371

150

151 151

Nam §Þnh
652

156
157
340

650

339

338

337

336

335

334

333

339

338

337

336

335

334

375

311

157

333 332 158

Trùc Ph-¬ng
(H)

160

312
377

313

Th¸i B×nh

161
161

348 348

349
163

656

350
164
351

Fig. 2: Computation Scheme

164

351
165

S«ng Trµ LýS«ng Hång

165
653

352

§«ng Xuyªn (H)

315
163

350
652

657

§«ng Xuy ªn (H)

314

314
162

162

349
360

525

313
160

347
347

362
359

524

376
312

159

159

346
346
651
655

360

524
376

311

158
340
345

654

352
166
166
353

658

S«ng §¸y

315

353

167

654

167
354

659

655

354

328

168

S«ng Ninh C¬

168

328
169

169
329

170

660

329

170
171
656

330

171
172

661

330

172
358

657

173
173

358

662
658

359

174

174

331
331
332

H×nh S¬ ®å tÝnh thuû lùc theo m« h×nh VRSAPhÖ thèng S«ng Hång - Th¸i B×nh
(tµi liÖu ®Þa h×nh n¨m 2000)

175

Nh- T©n (H)Phó LÔ (H)

Ba L¹t (H)Ba L¹t (H)Figure 2: Computation scheme

Hydraulics Computations to Study Flood Control for Ha Noi City, Viet Nam
99

65

October 2004, Agra, India
2.1.1 Boundary conditions
Upstream boundary conditions are flows at 4 hydrological stations: Hoa
Binh, Yen Bai, Vu Quang, Thac Buoi, Cau Son, and Chu stations.
Downstream boundary conditions are tidal water levels at 12hydrological stations: Nhu Tan on Day River, Truc Phuong on Ninh Co
River, Ba Lat on Red River, Dinh Cu on Tra Ly River, Dong Xuyen on Thai
Binh River, Kinh Khe on Van Uc River, Kien An on Lach Tray River, Cua
Cam on Cam River, and Don Son on Da Bach River.
Cross section data measured in 2000 and hydrological data including
water levels and discharges at hydrological stations are used in thecomputations.
2.1.2 Model calibration and verification
Flood data in the year of 1996 are used for model calibration andflood data in the year of 2000 are used for model verification.
From model calibration and verification, it is found that the computed
results of water levels and discharges are in good agreement with themeasured data, absolute error are small as shown in Table 1.
Table 1: Results of Model Calibration and Verification
StationAbsolute Error
in Water Level (m)Calib.
Verif.

Absolute Error
in Water Level (m)Calib.
Verif.

StationPhu Tho

0.08

0.11

Nam Dinh

0.05

0.30

Trung Ha

0.28

0.28

0.12

0.18

Viet Tri

0.19

0.27

0.11

0.01

Son Tay

0.04

0.07

Dap Cau
Phu LangThuongPha Lai

0.05

0.25

Ha Noi0.17

0.29

Ben Binh

0.04

0.20

Thuong Cat

0.02

0.28

Cat Khe

0.05

0.12

Ben Ho0.08

0.29

Phu Luong

0.25

0.29

Hung Yen

0.18

0.08

Ba Nha0.05

0.15

Trieu Duong

0.06

0.22

Trung Trang

0.25

0.26

Chanh Chu

0.20

0.03

An Phu0.01

0.13

Tien Tien

0.24

0.00

Cao Kenh

0.15

0.05

66

New Technologies for Urban Safety of Mega Cities in Asia
100

ICUS Report 6


2.2 Computation scenarios
Basing on the socio-economic, topographic, hydrological andhydraulic conditions of the Red River Delta, 36 emergency spillways on thedike system are identified with the concept of accepting certain damage but
avoiding disaster due to dike break.
Characteristics of the spillway such as location, width and crest level,and storage capacity of the downstream area are used in the computations.
All the existing flood control measures in the Red River basin are
applied, i.e., Hoa Binh Reservoir regulation, Day River flood diversion, andflood detentions areas.
Two cases are considered in the computations: (1) Case A: Natural
flood in the Red River with 1000-year return period, and (2) Case B:
Natural flood in the Red River with 2000-year return period.
Case A: Natural flow at Son Tay station is 53,000 m3/s (1000-year return
period). Three scenarios are considered:Scenario A.1: Applied all existing flood control structures i.e.,
flood regulation, flood diversion, and flood detention, but
without using emergency spillway. This is to study the capacityof the existing flood control structures in coping with extreme
flood.
Scenario A.2: Applied all existing flood control structures and all
the identified spillways.
Scenario A.3: Applied all existing flood control structures andonly some of the identified spillways in the upper part of theriver basin.

Case B: Natural flow at Son Tay station is 60,000 m3/s (2000-year return
period). Three scenarios are considered:Scenario B.1: Applied all existing flood control structures, but
without using emergency spillway.
Scenario B.2: Applied all existing flood control structures and all
the identified spillways.
Scenario B.3: Applied all existing flood control structures andonly some of the identified spillways in the upper part of theriver basin.

2.3 Results and discussion:
Results of computations for Case A (flood with 1000-year return
period) for different scenarios are shown in Table 2. From the results, it isfound that:

Hydraulics Computations to Study Flood Control for Ha Noi City, Viet Nam
101

67

October 2004, Agra, IndiaWith the use of the existing flood control structures (Scenario A.1),
maximum water level at Ha Noi reaches a value of 14.97 m, i.e.,
0.77 m higher than the designed flood water level at Ha Noi. The
existing flood control structures in the Red River basin cannot
cope with 1000-year return period flood, emergency spillway isfound necessary.
With the use of the existing flood control structures and all theidentified spillways (Scenario A.2), maximum water level at Ha
Noi reaches a value of 13.46 m, i.e., 0.74 m lower than thedesigned flood water level at Ha Noi. The spillways together withthe existing flood control structures in the Red River basin cancope with 1000-year return period flood.
With the use of the existing flood control structures and somespillways upstream of Ha Noi (Scenario A.3), maximum waterlevel at Ha Noi reaches a value of 13.58 m, i.e., 0.62 m lower thanthe designed flood water level at Ha Noi. The spillways upstreamof Ha Noi together with the existing flood control structures in the
Red River basin can cope with 1000-year return period flood.



Table 2: Results of Computations for Case A (1000-year flood)
Scenario

Water Level at Station
Son Tay
Ha NoiT. CatPha Lai
A.1
18.09
14.97
14.44
9.16
A.2
17.07
13.46
13.05
7.57
A.3
17.12
13.58
13.15
7.58
Note: Designed water level at Ha Noi is 14.20 m

Hung Yen
9.36
7.91
8.04

Results of computations for Case B (flood with 2000-year return
period) for different scenarios are shown in Table 3. From the results, it isfound that:68With the use of the existing flood control structures (Scenario B.1),
maximum water level at Ha Noi reaches a value of 15.86 m, i.e.,
1.66 m higher than the designed flood water level at Ha Noi. The
existing flood control structures in the Red River basin can notcope with 2000-year return period flood, emergency spillway isfound necessary.

With the use of the existing flood control structures and all theidentified spillways (Scenario B.2), maximum water level at Ha
Noi reaches a value of 13.95 m, i.e., 0.25 m lower than thedesigned flood water level at Ha Noi. The spillways together withthe existing flood control structures in the Red River basin cancope with 2000-year return period flood.

New Technologies for Urban Safety of Mega Cities in Asia
102

ICUS Report 6With the use of the existing flood control structures and somespillways upstream of Ha Noi (Scenario A.3), maximum waterlevel at Ha Noi reaches a value of 14.09 m, i.e., 0.11 m lower thanthe designed flood water level at Ha Noi. The spillways upstreamof Ha Noi together with the existing flood control structures in the
Red River basin can cope with 2000-year return period flood.
Table 3: Results of Computations for Case B (2000-year flood)

Scenario

Water Level at Station
Son Tay
Ha NoiThuongPha Lai
Cat
B.1
19.01
15.86
15.28
9.49
B.2
17.96
13.95
13.55
7.6
B.3
18.04
14.09
13.69
7.61
Note: Designed water level at Ha Noi is 14.20 m

Hung Yen
10.04
8012
8.29

3.0 CONCLUSION
The existing flood control structures of the Red River basin cannot
cope with extreme flood with 1000-year return period. Although, all themeasures are taken, water level at Ha Noi is still higher than the designed
value of 14.2 m.
Application of emergency spillways on the dike system cansignificantly reduce water level at Ha Noi. A number of scenarios arestudied and it is found that spillways in the upstream of Ha Noi are more
effective in reducing flood water level at Ha Noi. With the use of thesespillways, water level at Ha Noi can be kept lower than the designed value
for the case of 2000-year return period flood.
REFERENCES
Thuc T., Phuc N. H., 2003. Hydraulic computations for determining
emergency spillway for the Red River system.
ADB, 1995. Red River Delta Master Plan.
US Army Corps of Engineers, Hydrologic Engineering Center, 2001. UNET
One Dimensional Unsteady Flow Through a Full Network of OpenChannels, Version 4.0.
US Army Corps of Engineers, Hydrologic Engineering Center, 2001.
HECRAS Hydraulic Reference Manual.



Hydraulics Computations to Study Flood Control for Ha Noi City, Viet Nam
103

69

SUSTAINABLE DEVELOPMENT OF
WATER SUPPLY, SANITATION
AND WASTE MANAGEMENT: A
CHALLENGE TO DHAKA URBAN SLUM
DWELLERS IN BANGLADESH
AYSHAAKTER1 AND ROWSHAN MAMTAZ2
1
School of Civil Engineering, AIT, Thailand
2
Associate Professor, Dept. of C.E., Dhaka, Bangladesh
aysha_akter@yahoo.com


ABSTRACTThe new ethic of ‘Sustainable Development’ in basic urban facility likewater supply, sanitation and proper drainage system for waste disposal is
now being supported by a number of technologies to achieve it in reality.
Most of the developing countries’ urban slums receive few or no facility.
Albeit there are several cost-effective basic infrastructures/services from theslum improvement providers (both public and private) but the poor situationof urban facilities still prevails in these settlements. That is because after
providing these infrastructures/services, within a very short time most areeither fully ruined or exist in a very shocking condition. The problem isparticularly acute in the capital of Bangladesh - Dhaka, where about 33
percent out of total Dhaka’s population live in slum/squatter settlements
within abject physical and environmental conditions like: out of total slum
dwellers about 20 percent have land-access, 30 percent’s houses blessed of
piped water supply, 20 percent have sanitation access and only 10 percent
receives proper waste management facilities. There are lots of community
based approaches which are positively influencing the long- run services
but due to slum’s legality these facilities cover only one/two sector without
any incorporation. Against this backdrop, an urgent ‘Sustainable
Development’ is required to provide slum dwellers’ elementary needs
through an integration of both technical and managerial. This paper
focused narrow down at the existing facilities in context of non-slum area
and identifies the responsible factors to achieve sustainability. The main
discussion is devoted for improved Dhaka slum’s basic services throughboost up the existing participatory approach to cope the challenges behindsustainability and finally come up with possible solution as an integrated‘Rainwater Harvesting’ and ‘Bio-Gas Plant’ in corporation with the‘Community Construction Contracts’. This paper concludes the proposed
community-based cost-effective infrastructure can be accomplished therequirements of slums ‘Sustainable Development’.

31104

October 2004, Agra, India
1.0 INTRODUCTION
The current slum population in the urbanizing world is about 928
million (UN-HABITAT, 2003) increases inevitably the needs for economic
solution of water supply, sanitation and waste management. That is why the
Sustainable Development took center point in worldwide development as aresult of the Earth Summit (UNCED) held in Rio de Janeiro, Brazil, in 1992.
However for proper realization recently the World Summit on Sustainable
development, Rio+10, held in Johannesburg in 2002 has postulated the‘Plan of Implementation’ stated that “…Integrate sanitation into water
resources management strategies” (WSSD, 2002).The importance ofsustainable development is already being aware by the developing countries
but for successful implementation should be started from the mostvulnerable part i.e. the urban slums. The fifth mega city of the world, Dhaka
is in crying need to get rid from the inadequacy of water supply, sanitation
and waste management services from its slum. So, in this circumstance how
far Dhaka slums to achieve sustainability. For the exact answer just have alook back, in 1996 there were 3,007 slums and squatter settlements for 1.3
million people in the Metropolitan Area (the Centre for Urban Studies i.e.
CUS survey, 1996). And the current estimated population for 2002 of theslums in and on the fringes of the Dhaka would be somewhere between 2.5
million and 3.0 million of the greater Dhaka Metropolitan Development
Plan (DMDP) (1995-2015) (Figure 1).
P r o je c te d
S lu mG r o w ho f o th e r c o m p o n e n ts

G r o w th

1 4

1 3

Population Variation

1 2
1 0

9 .8

9 .2
8 .4

8
6

8

7 .3
6 .5

6

6 .2
4 .8

4

3 .7
3
2 .2

2

1 .5

0
1 9 9 01 9 9 52 0 0 02 0 0 52 0 1 02 0 1 52 0 2 0Y e a rFigure1: Growth chart of city’s population and slum population in DMDP
area (Nawaz, 1999).
The current population of the same area under the above plan isaround 10.0 million. According to the same plan by the year 2015, the total
population of DMDP area would be in 17 million. The slum population
unless corrective policies are adopted and implemented, would range
between five and six million. In excess of thirty five percent of whole
Dhaka would be living in unauthorized land and in miserable slum
conditions. The living conditions of the city in general and that of the slums
in particular while bad as they are today, it needs initiatives to be taken to
decrease the miseries of the slum people. There may be difference ingetting facility for the slum’s situational condition like the slum situated in a

32

New Technologies for Urban Safety of Mega Cities in Asia
105

ICUS Report 6
residential or commercial area might get special facilities rather than in a
sub-urban area and vice versa. To get the exact picture eight slums havebeen selected from residential area (Kal-a-Wala Para Bastee, Nashimbag
Bastee and Kallayanpur 4no. Pora Bastee), industrial area (Beg Rubber
Industry Slum, Omor Sons Slum and Tiger Slum) and sub-urban area (West
Vasantek Slum and West Vasantek 1 no. Slum). An intensive field survey
on the prepared questionnaire has been conducted through door to door
survey by random sampling and simulation with secondary informationfrom different government and non government organization has been used
for supporting primary information (Dhaka City Corporation i.e. DCC andDhaka Water and Sewerage Authority, DWASA, Dusthaya Shathaya
Kendra i.e. DSK, Waste Concern and others) (Akter, 2003).
2.0 EXISTING SITUATION
About half of the slum dwellers have no access to formal sources ofwater, very few of them have access to common sanitary latrine and slums
have very poor garbage collection systems (Figure 2).

(a) Water collection(gathering)(b) Common latrine(discharging to water body )(c) Solid waste (uncollected)(d)Drain (jammed)

Figure 2: Existing overall Dhaka Slum situation
In recent years, however, the Dhaka City Corporation has been
continued supporting the slum communities’ to access water supply,
sanitation and primary solid wastes collection system through someinnovative program by engaging the different private organizations but stillit’s a lengthy way towards the success through an integration between
services as well as service providers.

Sustainable Development of Water Supply, Sanitation and Waste Management
10633

October 2004, Agra, India
2.1 Water supply
From the field survey it is observed that in the slums (Figure 3), themain source for drinking water is the supply water from Dhaka Water andSewerage Authority (i.e. DWASA), which is of the same outlook with thefindings of Coalition for the Urban Poor i.e. CUP which shows about 76.1%
slum people use DWASA water for drinking purpose (CUP, 1998).
Residential

80

Industrial

Sub-urban

70

Percentage of Users

60
50
40
30
20
10
0
Water point

Community Tube well/ Public Water source of neighboringStandslums / pond/ other water
bodiesAvailable Services

Figure 3: Use of water sources (percentage) in the study areas
The DWASA is charging Tk. 5 (1US$=Tk 58) for 1,000 liters of water.
In the slums of Dhaka the households are paying Tk.1 for 20 liters of water.
This means that slum households are paying almost ten times more than the
DWASA rate. However the system for storing DWASA water, the “Water
Point” takes about Tk. 0.5 for 20 liters of water. Field survey shows themonthly income of the slum dwellers varying from Tk. 3,000 to 5,000. If it
is consider their average monthly income Tk. 3,500 (As according to ADB
1996 study of Urban Poverty referred to the poverty line at Tk.
3,500/month/family in Bangladesh) and daily demand for water 500 liter per
capita/family; then the total cost spends only for water will be [(500÷20) x
0.5 x 30 days] i.e. Tk. 375 which is about 11% of their monthly income
whereas for the city dwellers the investment is hardly 1.5% of their income.
One study from Asian Development Bank i.e. ADB showed manyslums got illegal water connection (ADB, 1996); in this study illegal
connection was also found in only one slum – West Vasantek no.1 slum,
although the slum dwellers showed their interest to pay for better watersupply. Among the study areas almost all but specially in two (Kallayanpur
4no. Pora Bastee and West Vasantek) slums have a quite large number
inactive tube-well those are provided (by different GOs and NGOs projects)
in the last 2/3 years due to lowering of ground water and lack of proper
observation. For other cases different sources including stagnant rainwater
pools serve them which are mostly unhygienic due to improper collection
system the ‘first flush water’ of the rain has allowed for preservation andalso inadequacy in cleanliness. So that some sever illness like diarrhea (due34

New Technologies for Urban Safety of Mega Cities in Asia
107

ICUS Report 6to mixed dirty water from roof carry the epidemic germs) make them scareto use rain water.
2.2 Sanitation
It is revealed that the sanitation situation is worse than water supply
situation in slums as well as in the full city area. Among the sanitary facility,‘Pit Latrine’ is the main mode of sanitation for the slum people. It isestimated that about 20 percent of slum dwellers have access to suchcommon sanitary toilets. The field survey showed that the Beg Rubber
Industry slum has a better option for the slum dweller which is named‘Sanitation Block’ with separate systems for male and female; it costs
Tk.0.5/use of toilet. For emptying the pit ‘Vacutag’ machine is used toempty the human wastes and transport to an appropriate safer disposal ortransfer site. On the other hand common pit latrine provision in residential
area’s (Kal-a-wala para and Nasimbag) slum has designed for 6 households/toilet and costs Tk.40/month/household (Figure 4).
60
Residential

Industrial

Sub-urban

Number of Toilets

50

40

30

20

10

0
Latrine available(simple pit latrine)

Kucha and hanging

Open latrine

Sanitation Block

Type of Toilet

Figure 4: Variation in quality and availability of latrine facilities in thethree study areas.
In West Vasantek slum the discharging pipe connected to adjacentwater body although there is screen at the end of the pipe which protects thelatrine to enter any wastes from outside (Figure 1c). The situation becomes
noticeable in rainy season due to absence of drainage system. The overallsituation of the West Vasantek 1.no slum is also worst as in this area has
only one option which is the hanging toilet mostly on adjacent water body,facing a enormous problem like health problem due to contact with dirty
water in every monsoon.
2.3 Waste management
According to a study of Center of Urban Studies i.e. CUS (1998),
about 90% of the slums do not receive municipal solid waste collection
services although the slum dwellers generate relatively small amount ofwaste per person. The solid waste from the slums are mostly disposed in
nearby water body (Figure 1 d), low-lying areas and drainage ditches or

Sustainable Development of Water Supply, Sanitation and Waste Management
10835

October 2004, Agra, India
simply scattered in adjacent non-occupied areas. From the field study, it isobserved that there are variations of the existing wastewater disposing
practices in the three classified areas which is really alarming (Figure 5).
Residential
100

Industrial

Sub-urban

100

95

94

%of Slumdwellerscoveredbybins

90
80
70
60
50
40
30
20
10

5

6
0

0

0

0

0
DCC communal bin

Closed bin

Open place

Type of Solid Waste Collection

Figure 5: Drainage practices in the three areas (qualitative measure)
The two residential slums (Kal-a-wala para and Nasimbag slum) has
got the practice of door-to-door collection of solid waste leading tocommunity-based decentralized composting (namely ‘Barrel Composting’)
program run by Waste Concern (Table 1) .
Table 1: Availability of Solid Waste Collecting Bins in the three areasIndicator
Residential
Industrial Sub-urban
(%)

(%)

(%)

DCC communal bin

5

6

0

Closed bin (Barrel system)

95

0

0

Open place

0

94

100


The success comes from this ‘Barrel Composting’ program as theparticipant households are getting Tk. 2/kg of wastes from this facility
provider. This program is sustainable due to its conversion process oforganic (bio-degradable) portion of the waste to compost i.e. organic
fertilizer. Although the carbon nitrogen ratio of solid waste is slightly higher
like carbon 22.6% and nitrogen 0.41% in Dhaka, besides the optimum
carbon nitrogen ratio 35 to 50 for aerobic composting, with some additional
animal excreta the composting has finished within 40 days (Waste Concern,
2000).This excellent program attracts other slum dwellers due to its income
generation opportunity.
3.0 RESPONSIBLE FACTORS
There are number of factors, which have significant roles in thedevelopment of slum’s overall situation. This study observed that the36

New Technologies for Urban Safety of Mega Cities in Asia
109

ICUS Report 6
situation of slums located in sub-urban area or periphery of the city area isworse in all basic services than those located in residential and industrial
areas. The slums located at residential areas get relatively better facility thanothers slum area. So, the location is one of the responsible factors for slums
that have a little effect on its overall development for service condition andquality. The sub-urban slums are not getting much attention from the slum
dwellers development providers Government Organizations (GOs) and Non
Government Organizations (NGOs) due to the gap in cooperative
relationships between the service provider and slum leader. If local leader
do not cooperate, the GOs and NGOs organization cannot implement any
development activities successfully. The success rate of development
activities like ‘Water Point’, ‘Tube-well’, ‘Common Latrine’, ‘Sanitation
Block’ and ‘Barrel Composting’ by both GOs and NGOs proves if the slum
community is properly aware, convinced, motivated and guided how thesituation changed positively. So, for overall development the community
participation can be taken as a prerequisite factor.
4.0 POSSIBLE SOLUTION FOR SUSTAINABILITY
In context of above existing situation, the factors can be identified as
challenge to cope with sustainability, are: first of all limited resources andtheir mismanagement then the contradictory behavior of existing policies ofslum’s water supply and sanitation right, and the overall role of community.
To ensure sustainable solution, the water sources should be taken care fromfurther groundwater extraction and surface water pollution. Small scale
recycling of wastewater like ‘Duck-weed Wastewater Treatment’ or any
such type cost effective approach can be a great initiative. The slum which
got quite large bare land (like West Vasantek no.1 of 48 acres for 2500
household can get effective supply by introducing a ‘Pond Sand Filtration’i.e. PSF. But due to regular migratory place, initiatives for the wastewater
treatment or PSF will not be a sustainable solution. Reinforcing of‘Rainwater Harvesting’ can be achieved the target by proper plan andimplementation as there is a considerable rainfall i.e. nearly 85% of theannual average rainfall observed in May to September of every year in
Dhaka (Table 2).
Table 2: Monthly average Rainfall for Dhaka city(source: Weather Center Dhaka Bangladesh, 2003).
Jan
7.6

Feb
30.5

Mar
61.0

Apr
137.2

May
243.8

Jun
315.0

Jul
330.2

Aug
337.8

Sep
248.9

Oct
134.6

Nov
25.4

Dec
5.1

Annual156.11

So, the choice of “Rainwater Harvesting” with local construction
material for slum is sustainable solution. Only the supply side is not enoughin the way of development, there is an urgent need for demand side
management by establishment of existing law. This in turn, will allow
investments in extending piped water coverage. Metering of water
connection for non-slum area can be a great solution to overcome theSustainable Development of Water Supply, Sanitation and Waste Management
11037

October 2004, Agra, Indiamisuse both from Household connection and common pool connection, as
there most of the consumer pays tariff in property tax basis.
At present the government has targeted to ensure sanitation for all by
the year 2010 instead of 2015 which seems a grand offer for Dhaka slums.
But for slum dwellers income generating low cost option rather than theseparate toilet is far more attractive. For solid waste ‘Barrel Composting’itself a sustainable solution although the integration manner with the latrine
will diminish the slum drains blockage problem for every monsoon. Again
integration is required with water supply to ensure hygiene as well as
recycling or Waste Water Treatment to ensure sustainable slum environment.
“Bio-Gas Plant” can bring a radical change in this perspective as anintegration manner (Akter, 2004). For this circumstance, the outlet of thecommon toilet(s) incorporation with kitchen wastes as well as the othertypes of liquid/solid discharging outlet should be the main contributory partfor the whole process. The main process which takes place in a digester is inan anaerobic form. In the biogas digester, small micro-organisms (bacteria)
break down the human wastes and the organic kitchen wastes in the absenceof oxygen into a mixture of methane gas (CH4), carbon dioxide (CO2) andsmall amount of other gasses. For successful operation first of all, there is a
pre-requisite behavioural change required for using detergent in kitchen to
promote the bacterial death in the reactor otherwise it will be an excellent
integration approach to achieve the sustainability.
For example West Vasantek no.1 Slum
Population is 12,000 and households 2500 (secondary data DSK,
2002).According to Rahman (1996), potentiality of biogas generationconsists:
Gas generation
Human excreta

0.4 kg / day/ person

0.074 m3 / kg extra

Municipal waste

0.22 kg/head/day

0.06 m3/ kg waste

So, for West Vasantek no.1 slum the calculation shows a significant
outcome (Table 3).
Table 3: Bio-Gas generation for West Vasantek no.1 slum
Feed Materials

Total excreta

Gas may be obtained(kg per day)

(m3 per day )Human Excreta

4800

355.2

Kitchen Wastes

2640

158.2

Total

513.4

38

New Technologies for Urban Safety of Mega Cities in Asia
111

ICUS Report 6
So, in small scale for a community toilet which is used by 6/7 families
and with their kitchen wastes about three cubic meters of gas is produced in
one such plant at a cost of Tk. 15,000 to 20,000. The produce gas is enoughto meet up their cooking purpose as well as the output manure will be able
to bring some financial solvency. Usually such type of plant’s design period
for 30 years, however it’s totally depending upon the maintenance. The
wastewater outlet in addition to the human excreta and kitchen wastes willmeet the required water (normally to dilute wastes the required water is
twice of the waste weight). And the collaboration of a pipe connection fromrain harvested roof will be an immense pulse in the way of sustainability.
To upgrade the proposed solution i.e. ‘Rainwater Harvesting’ and‘Bio-Gas Plant’, there is an enormous need for policy. So, in conjunction
with these infrastructures a proposed policy is “Community Construction
Contracts” which is based on the concept of active community
participation in physical upgrading of their neighbourhoods. The expectedadvantage of this approach is the improvement of construction quality andthe creation of responsibilities on the side of community for the design andconstruction as well as for the maintenance and repairs after its completion.
So, the “Community Construction Contracts” will be able to place
integration between the technical and managemental aspect such as:
Technical AspectHigher quality of works will be ensured because the community has a
stake in the product; andDue to community ownership a provision of community required
services can be attained more rapidly than a commercial contractor.

Managemental Aspect

Job opportunity will be generate for skilled and unskilled persons inthe settlement;The participants will be able to get the technical, administrative andmanagement experiences practically on the job; andSuch type of small scale ‘Bio-Gas’ plant will save the fuel wood andfertility of soil and overall for sure it will keep the soundness ofenvironment through pathogen free discharge and pollution free air
leading to a healthy atmosphere for the inhabitants. In the long run it
will be great deals of sustainability through conserve the soil
productiveness and the trees.

Sustainable Development of Water Supply, Sanitation and Waste Management112

39

October 2004, Agra, India
5.0 CONCLUSION
The great examples of ‘Water Point’ and ‘Barrel Composting’ showthat the enhanced community participation in decision level become really
successful for most of the pioneering technology. ‘Community
Participation’ successes for many country as well as Bangladesh andhopefully it will be succeed to improve the slum dwellers’ lifestyle in termsof sustainable safe water supply, sanitation and waste management. As thestudy illustrates cent percent respondents from unserved slum group showedwillingness to pay for betterment so ‘Community Construction Contract’will bring the targeted achievement incorporation with the integrated ‘BioGas’ system. Although more intensive research and field works are required
for Dhaka slums.
REFERENCES
ADB 1996. Urban Poverty Reduction Project (ABD TA 2410- BAN. ADB
Draft Final Report. ADB, Government of the People’s Republic ofBangladesh, Local Government Engineering Department, International
Development Support Services, Bangladesh Consultants Limited andProshika, November, Bangladesh.
Akter A. 2003. Water Supply, Sanitation and Solid Waste Management
Situations of Selected Slums in Dhaka City. M. Engg. Thesis,
Department of Civil engineering, Bangladesh University of Engineeringand Technology, Dhaka, Bangladesh.
Akter A. and Mamtaz R. 2004. Integration of Urban Facilities: A Great
Sustainable Remedy to Urban Slum Dwellers in Dhaka (Bangladesh).
Pro of the 1st KMITL International Conference on Integration of
Science & Technology for Sustainable Development Bangkok, Thailand,25-26 August 2004. Vol: 183-186.
Coalition for the Urban Poor (CUP) 1998. Baseline survey of environmental
sanitation, hygiene and water supply in urban slums of Dhaka City.
Dhaka, Bangladesh.
Center for Urban Studies (CUS), Dhaka 1996. A comprehensive Summary
Report.
Nawaz T., 2002. Dhaka City and possible slum resettlement programme.
CUS Bulletin (No. 42) January - June (Special Issue: Thirteenth CUS
Anniversary).
Rahman, M.H., 1996. Biogas: environmental aspects and potential for
generation in Bangladesh. International J. Env. Educ. & Inf., (Publishedby Environmental Resources Unit, University of Salford, U.K.
UN-HABITAT, United Nations Human Settlement Program 2003.The
Challenge of Slums-Global Report on Human Settlements 2003.Waste
Concern, 2000. Aborjona O Poribesh, September, Dhaka , Bangladesh.
World Summit on Sustainable Development, Rio+10, Johannesburg 2002.
Poverty eradication, sanitation, energy, financing, integrated water
resources management. Africa.

40

New Technologies for Urban Safety of Mega Cities in Asia
113

THE NEED FOR AN INTEGRATEDDISASTER MANAGEMENT STRATEGY INNORTH AFRICAN MEGACITIES:A CASE STUDY OF ALGIERS
DJILLALI BENOUARUSTHB, Civil Engineering Faculty, Alger, Algeria.
dbenouar@yahoo.com
ABSTRACTAs many other countries of the world, the northern African countries
also suffer from environmental and geological problems, among others, thelarge cities and their suburbs. The capitals, particularly, represent
gravitational poles constitute true economic metropolises of them, recording
a considerable migratory flow in addition to one important demographic
growth, a fast industrialization and an anarchistic urbanization, whichmake of it the receptacle of various sources of pollution, where ground, airand sea do not escape the consequences of these plagues. Furthermore,
Algiers have had also suffered from storms, floods, landslides andearthquakes. Algiers in this research work, capital of Algeria, is taken as acase of study because it introduces most of the risks met in the othercountries of North Africa. Algiers counts more than 3 million inhabitants foran area of 809.19 km2. From the independence of Algeria in 1962, Algiers
was found constituted of a dense urban fabric where various functional
scales were overlapped. The town of Algiers experienced a significant
development as well on the urban level as industrial and of this fact it isseen confronted with a degraded environment and a multiform pollution.
The industrial sector and the factories established in urban fabric and its
periphery are at the origin of the existing or potential sources of pollution in
addition to the consumption of space.
1.0 INTRODUCTION
For the North African countries, geological, environmental andtechnological hazards constitute a constant threat to human life and property,
sometimes causing major economic losses and disruption. The rapid
urbanization, development of critical engineering works such as dams,
decaying building stock, implementation of various industries within andaround the main cities, industrialization of cities with modern types ofbuildings and the large concentration of populations, with a heavy
dependency on infrastructure and services, living in large cities and/or
settling in hazardous areas are matters of growing concern, as they
contribute to heavier loss of life and seriously increasing the economic
losses in future disaster damage. The environment concerns and anincreased official and public awareness of various hazards have, in the last
decade, led to a rapid rise of interest in hazard and risk evaluations and thus
in disaster risk management.

173
114

October 2004, Agra, India

In fact, there are various reasons for investigating the Mediterranean
Africa as a unit and for evaluating the various hazards of the entire zone
under similar criteria: (1) In terms of geological process: the countries
limiting the southern part of the Mediterranean Sea and its adjacentcontinuation in the Atlantic Ocean have had, since hundred million years
ago, the same tectonic process marked by a relative motion alternating
between left and right lateral along the border of the African and Eurasianplates, (2) Similar present level of development: the actual state ofdevelopment in the whole zone is dominated by a rapid urbanization, highdensity of population in most important cities, degradation of theenvironment, (3) at the present pace and patterns of rural-to-urban migration
and unplanned urbanization are causing increased population densities inurban centers, such areas are a prime reason for increasing vulnerability, (4)Similar historical development: the historical development of the countries
in the region shows many common factors, such as cultural background.
Similarities in population settlements, building stock characteristics andsocio-economic and demographic conditions, various types of pollution,
climate, etc., are very important parameters in the whole process of disasterrisk studies in most cities in the zone under consideration. For all thesereasons, this research work is concentrated on the city of Algiers, which
presents a general case of most of the geological, environmental andtechnological threats found in all the main cities across the Mediterranean
Africa.
Algiers, the Capital of Algeria, including its surroundings
communities, has a population of approximately three millions, represents
the most important concentration of investment, government institutions andpopulation in the whole country. It is the intellectual, social, political andeconomic center of the country. In recent years the disaster risks haveincreased due to overcrowding, faulty land use planning and construction,
inadequate infrastructure and services, and environmental degradation andtechnological plants within and surrounding the city. In the last two decades,
the city of Algiers and its surroundings have known an importantdevelopment in the urban domain as well as in the industrial one and thus itis actually confronted to rapid environmental degradation and to a
multiform pollution. The industrial sector implemented within the city itself
and its surroundings increases considerably the risk of disasters. Algiers is
confronted seriously to all risks as earthquakes, floods, landslides, as well as
the industrial pollution (4 Industrial zones), atmospheric pollution (roadtraffic, main industries, Public dump Oued Smar), Solid wastes pollution(Public dump Oued Smar, units for wastes treatment), Hydro pollution(superficial and underground water), marine pollution, soil pollution, forestsand green spaces degradation, as well as to geological risks. The topography,
the waterfront location and the ancient neighborhoods (Casbah) make it
difficult to affect radical solutions to most of its problems. Decision-makers
need adequate integrated information on the likely (probabilities) intensityof the disaster the city will face if they are to reduce disaster vulnerability.
This research work shows the need of an integrated disaster risk
management in megacities.

174

New Technologies for Urban Safety of Mega Cities in Asia
115

ICUS Report 6

2.0 INDUSTRIAL POLLUTION
The industrial activity constitutes a most significant source ofpollution and harmful effect in the city of Algiers. It is the origin of several
forms of pollution as hydrous pollution and atmospheric; it is also
generating dangerous and toxic wastes posing serious problems for thehealth of the people as well as their elimination.
Great Algiers represents one of the most significant areas of thecountry, from the point of view of the industrial activity. The total numberof industrial units is approximately 735 public and private in the Wilaya of
Algiers, that is to say 7.2% of the national total estimated at 10 200 units, ofwhich 5 242 would be located on the coast.
The polluting industrial activity is localized with the periphery of
Algiers, mainly in the East at the industrial zones of Gué de Constantine (8km of the center town), of El Harrach (11 km of the center), Oued Smar (15km) and Rouiba - Réghaia (27 Km).
The most polluting units on the level of Algiers are:








Paper mills,
Manufacture of batteries,
Oils and soaps,
Yeasts, detergents, metals heavy,
Pharmaceutical products
Fertilizers,
Petroleum products: gas, gasoline, asphalt…

2.1 Air pollution
The principal sources of pollution in Algiers are:

Very intense road traffic,
Rejections of pollutants by the industrial units established in urban
fabric and by the various industrial zones,
The combustion of the wastes at the public damp of Oued Smar.

2.1.1 Road traffic
The automobile park of Algiers counts approximately 560 000
vehicles all categories mixed (with a daily traffic of 1500 to 2000
vehicles/hour), which represents the quarter of the national automobile park.
This pollution consists approximately to CO2 15%, 60 à.70% of CO, 40 to
50% of NO, 30% of the hydrocarbon none burnt residues, SO2 5%, black
fume, dust, lead, etc,.

The Need for An Integrated Disaster Management Strategy in North African Megacities
116

175

October 2004, Agra, India

A quantity of 180 tons lead/year is emitted in the streets of the capital
at a rate of 0.5g of lead/liter of gasoline for the vehicles, that is to say anannual average of 3.8mg/m3 (average higher than that of the capitals of theother countries). The annual average recommended by WHO, as a standardof quality of the air not to be exceeded, ranges between 0.5 and 1 mg/m3.
Whereas lead concentration in the agglomeration of Algiers east of 2.01
mg/m3 (Aoudia, 1996).
2.1.2 The main industries
The most polluting industries are:









Te cement factory of Rais Hamidou which emits cement dust
charged with combustion gas NO, CO2 and of CO, is 30 tons of
dust/day (the standard ranges between 15 to 250 tons/Km2/year)(Service environment and forests, 1990). This cement factory,
localized within the heart of an urban zone (to 10 km west of thecenter of Algiers), unquestionably constitutes a significant
harmful effect for the populations resident and the wholeenvironment in the vicinity. Producing 750 tons of cement per day,this cement factory emits fine particles, made up mainly by
products limestone, which generate respiratory diseases. The mostvisible impact is certainly the deposit of cement dust on the roofs,
the vegetation and on the entire zone close to the cement factory.
The threshold of 1000g of dust/100m2/month, determined by amodel of dispersion as a norm, is largely exceeded on a radius of
3 km (INGECO, 1997).
The tobacco production units of Bab El Oued and El Hamma(both located within the center of Algiers) emit harmful fume dueto the use of fuel.
The unit of cable-making of Oued Smar emits dust charged withlead,
The industrial unit of the greasy substances in the harbor of
Algiers emits fume with nauseous odors,
The manufacturing plant of batteries of Oued Smar emits leadoxide dust,
The manufacturing plant of painting within Oued Smar emits gas
dust charged with asbestos and lead,
The refinery of Baraki (localized to 12 km of the center of
Algiers) releases various hydrocarbon gases,

2.1.3 Public dump of Oued Smar
It releases nauseous fume, odors and gas emissions (CH4, CO2, NH3)
from the combustion of the household refuse of the city of Algiers, its
surroundings and the industrial zones. This pollution is visible at Oued Smar,
El Harrach, Bab Ezzouar, Hamiz, Dar El Beida and Eucalyptus.

176

New Technologies for Urban Safety of Mega Cities in Asia
117

ICUS Report 6

3.0 POLLUTION BY SOLID WASTE
Solid urban wastes can be defined like the whole of the solid waste
generated by the urban activity. In Algeria, in particular in Algiers,
household refuses pose serious difficulties to the public services to collectthem correctly, as they encumber the streets of Algiers and its surroundings.
Wild waste dumps on which the inhabitants come to deposit their waste
without paying any attention to the impact on the environment. I fact, thelack of information and awareness, and the non respect of the law, made thatthe citizen pours his solid waste anywhere, more particularly in the isolated
places and thus the creation of wild discharges. The estimate of the quantityof the waste generated by the agglomeration of Algiers is about 1 408 tons
per day (ANAT, 1996). The quantity of 2 500 tons per day is produced on
the whole of Wilaya of Algiers, that is to say 910 000 tons/year. Thisquantity will pass to 3 200 tons/day in 2005.
As for the industrial facilities, they pour daily more than 2 000 tons of
not controlled wastes, particularly asbestos, acid, cyanide, phosphorus, etc.
It should be also noted that waste of the slaughterhouses is rejected directly
into the public dump of Oued Smar.
The nature of solid waste is:Domestic Waste: 657 000 tons/year;
Industrial Waste: 930 000 tons/year;
Waste of the administrations (paper, paperboards, etc.) : 90 000
tons/year; Waste of the markets: 50 000 tons/year; Waste of hospital (syringes, bandages, etc.) : 3 900 tons/year; Waste of trade: 80 000 tons/year; Special Waste (toxic): 30 000 tons/year;(Service CPVA in Inspection of environment of Algiers).
3.1 Public dump of Oued Smar
Solid waste of the Wilaya of Algiers is forwarded to the single public
dump of Oued Smar just as well as the waste of the industrial zones. The
initial surface was 10 hectares and reached 37.5 hectares today. It is locatedat 13 km of the center of Algiers on a ground of a unit of clay. This public
damp reached a very advanced degree of saturation where the monticules ofstored waste exceed 6 meter high above the ground level. An investigationof a engineering and design department (Kaoula, 1996) estimated at 4 000
tons/day the quantity of waste which arrives on the discharge including 1
600 tons/day of domestic waste, that is to say approximately 1 000000
tons/year coming from Wilayates of Algiers, Boumerdes and Tipaza.
3.2 Hydrous pollution

The Need for An Integrated Disaster Management Strategy in North African Megacities
118

177

October 2004, Agra, India

Hydrous pollution is related to the disposal of the liquid and solid
wastes in the ground. Pollution reached today most of the hydrographic
networks and poses serious problems, on the one hand by the insufficiencyof the water resources, and on the other hand, because of the degradation of
the living conditions in the aquatic environment.
3.3 Superficial waters
The superficial water pollution is caused mainly by the sewage
systems deteriorated and not maintained where also pour the effluents in therivers. Sewage water of the of the city of Algiers and that of all the othercommunes of the Wilaya is rejected to the sea, either directly, or by themeans of Oued El Harrach. Oued El Harrach in which flow all the waste
water of the regions of El Harrach, Baraki, Eucalyptus, Bab Ezzouar, Dar El
Beida, Oued Smar, Gué of Constantine and even part of Wilaya de Blida.
The total volume of the wastewater poured in the Oued El Harrach isapproximately 57 000m3/day (IEA, 1997).
3.4 Underground waters
The water table of the plain of Mitidja constitutes the main water tankof the area. It is prone to many contaminations:

Pesticides, nitrate fertilizers
The liquid infiltrations of the water table
Nitrates of the catchments basin of Oued El Harrach.

The pollution of the water tables by hydrocarbons is a serious
problem since it can expand to surrounding collecting fields. Indeed,
drillings of the water table of Algiers were subjected of pollution byhydrocarbons. Most of drillings analyzed present a very high degree ofpollution, showing a largely higher index than the maximum permissible
concentration (10mg/litre) for the water intended for human consumption(Bruchet, 1985).
The discharge of domestic and industrial waste water without
treatment in the receiving medium constituted by a hydrographic network
which is characterized by nonpermanent rivers and relatively low flow notallowing a process of self - purification, dangerously threatens the watertable, the beaches, the dams as well as the public health.
3.5 Marine pollution
The bay of Algiers covers a water area of 184 ha, characterized by apollution of urban and industrial origin. Most of the cities in the Wilaya andindustrial facilities established on the of Algiers littoral pour their waste
water either directly to the sea, or by the means of the Oueds, without
preliminary processing which causes the deterioration the sea water quality.
At the Algiers harbor, 25 outlets of urban and industrial waste water were178

New Technologies for Urban Safety of Mega Cities in Asia
119

ICUS Report 6

listed, with presence of oils and greases coming from the harbor
maintenance workshops, the sewage waters of Hamma, the hospital
Mustapha Bacha, the factories of the fatty corps, the pasta production unit,
oil company and electricity production unit in addition to the draining
operated by the tankers and other ships either within the harbor or at large(Urbanis, 1998).
3.6 Soils pollution
The pollution of the soil may have its origin from the industrial
activities. The massive use of the artificial fertilizers, the use of certain
organic soil conditioners and the systematic use to the pesticides result in avery significant increase in the agricultural outputs; unfortunately this riseof the productivity of the grounds is often accompanied by the increase in
the contents of heavy metals in these grounds. Indeed, the contamination of
the grounds by heavy metals constitutes a phenomenon which results mainly
from the various human activities as the agricultural use of fertilizers(phosphates, fertilizers, organic soil conditioners,..), the industrial wastes,
etc. The analysis carried out in various places of the Mitidja plain shows acontent of nitrates between 50 and 250 mg/l, whereas the standard set by
WHO is 45 mg/l (ANAT, 1996).
4.0 DETERIORATION OF THE FORESTS (DEFORESTATION)
The forests of Wilaya of Algiers know actually a very advanced
deterioration covering a surface of 633 ha for a total surface of 5 338 ha,including 37 forests whose majority were arranged as entertaining forests.
The principal causes of deterioration of the forests are:







Attack of insects
Fires
Atmospheric pollution of origin generated by the industrial
activity; case of the cement factory of Rais Hamidou which
devastated the forest of Bainem
Neglect of the sector of the forests in the land use decisions
Anarchistic urbanization
Proliferations of the cities

5.0 FLOODS
Rapid urbanization is a major factor in the increase of floods. Flashfloods is a growing concern due to concrete which absorbs little water, thedecline of open spaces, engineering works that divert river flows and weakcity drainage systems (neglect, lack of maintenance). inappropriate housing
on river banks or near delta is a major concern.
The last Algiers flood and mudflow of 10 November 2001 whichcaused the loss of 712 human lives, injured 350, 116 are missing, and 1800

The Need for An Integrated Disaster Management Strategy in North African Megacities
120

179

October 2004, Agra, India

housing units suffered damage, 56 schools, scores of bridges, roads, public
works were damaged. 1000000 m3 (up to 10 m thick) of mud in the streetof Bab el Oued, more than 350 vehicles (cars, trucks and buses) withpassengers buried under mud. Preliminary cost U.S.$ 250 000 000.
6.0 LANDSLIDESRocks and soil sliding rapidly downhill. Mudflows and rock falls
triggered by earthquakes, storms, water logged soil and heavy
constructions.
Growing amounts of badly built housing on/below steep slopes,
on cliffs, or at river mouths of mountain valley. Landslides haveoccurred with or without the help of earthquakes. During the last
Algiers flood and mudflow of 10 November 2001, several
landslide cases were recorded within Algiers and its surroundings.

7. 0 EARTHQUAKES

Algiers, densely built, densely populated city located on seismic
zone. The city suffered several damaging earthquakes in the past,occurring within the city or in adjacent zones. The earthquake
catalogue for the Wilaya of Algiers goes back to 1365.
The building stock of the capital Algiers presents a highvulnerability to earthquake loads and thus seismic risk
management is really needed if the government wants to avoid
surprises

8.0 CONCLUSIONS AND RECOMMENDATIONS
Decision-makers need adequate integrated information on the likely(probabilities) intensity of the disaster the city will face if they are to reduce
disaster vulnerability. This research shows the need of an integrated disasterrisk management in megacities.
In a country which regrettably is a disaster-prone as Algeria or inother country, it is of crucial importance, at the macro-level, for the country
to have a well established and well regulated disaster management plan.
This will enable the government to avoid undue crisis management when
future emergencies occur. It is also of crucial importance, again at themacro-level, to integrate disaster management in all its facets withgovernment’s mainstream policies and plans for national development.
Disaster management and economic development are not two separate
disciplines that conflicts for resourcing. They are synonymous and theirresourcing should be a combined administrative process.
To fulfil these goals, the proposal of the establishment of a national
disaster research and management agency in Algeria has two objectives (1)to prepare the national disaster management plan and (2) to create a

180

New Technologies for Urban Safety of Mega Cities in Asia
121

ICUS Report 6

sustainable cadre of disaster management staff at all levels, and to promote
institutional and public awareness of disasters, their effects and likely relief
activities. The permanently established national disaster management
organisation is presented in what follows. The organisation chart describes
the structure, the chain of control and reporting, and the main working
relationships. It allows having a permanently established and functioning
integrated data collection system to gather information relevant to disastermanagement in all its aspects. However, it has a wider application andprovides an important step forwards an effective national data collection
system, and this will require extensive research work. Several partial databases are already available and these will be drawn upon in the creation of
the agency which will attempt to provide a more general view within asingle framework. The structure of the agency will then incorporate existing
government, non-government and community information/data sources inorder to provide an overall picture of potential danger zones, multi-sectoral
early warning indicators and available resources. This enables particularattention to be paid to problem geographic sectors or problem functions, andthe consequent mobilisation and allocation of resources in advance ofdisasters. A permanent structure for disaster management integrated in theAlgerian government is presented in Figure 1.
REFERENCES
Abdelouaheb, N. and T. Sadoun 1996. Evaluation de la pollution de l’eau
par les métaux lourds à l’aide des moules de la région d’Alger. incommunications 1er Séminaire Maghrebin sur l’eau, Université de Tizi
Ouzou (Algérie), Juin.
ANAT (Agence Nationale d’Aménagement du Territoire) 1996. Schémad’organisation de l’armature urbaine de la région métropolitained’Alger.
Aoudia, T. 1991. Pollution atmosphérique dans la région Est d’Alger. in
Etudes : Estimation des concentrations dans l’air à l’aide d’un modèle deboite ; CERHYD, Alger.
Bentir, M. 1995. La problématique des déchets solides en Algérie. Revue
EEC-Edil.
Bruchet, A. 1985. Recherche d’hydrocarbures dans les forages de la napped’Alger. Rapport Lyonnaise des Eaux, Laboratoire Central, France.
DVAHA 1990. Dossier Pollution et nuisances de la Wilaya d’Alger.
Division du développement des activités hydrauliques et agricoles,« Service Environnement des forêts de la Wilaya d ‘Alger », 241 pages.
IEA 1997. Rapport sur l’état environnementale. Inspection del’Environnement de la Wilaya d’Alger.
INGECO 1997. Audit environnemental de la cimenterie de Rais Hamidou(Rapport préliminaire).
Kaoula. A. 1996. Alger, une capitale malade de ses ordures. Revue« Symbiose », 34p).
Melha, A. 2001. Les enjeux environnementaux en Algérie. Pifp, June, Alger.
Programme du Gouvernement algérien pour l’an 2000.
Revues : « Algérie – Environnement », No. 1 and 2, 1998 and 1999.

The Need for An Integrated Disaster Management Strategy in North African Megacities
122

181

October 2004, Agra, India

Rouidi. L.1995. Les déchets solides urbains du Grand Alger. Revue Edil –Info. « Quantification, Caractérisation et propositions techniques pourleur élimination ».
Sellali. B. 1995. Influence des rejets urbain et industriels sur
l’environnement du littoral : Quelques exemples en Algérie. p.69.
AGEP : Actes de la Conférence Nationale sur la Nouvelle Politique del’Eau.
Urbanis 1998. Problèmes environnementaux dans le Gouvernorat du Grand
Alger.

Cabinetof the President
Strategic
Level

National Council of Disaster Management
National Agency for Research &Coordination of Disaster Management

LINE MINISTERS
CGS, CNERIB, COMENA,CTC ANB EPEAL
CNIG, CRAAG, ONM, ANRH,
ANB, CIVIL
CNES, CREAD, SAA,
LCTP CTTP CAAR

AlgerianRed

UN
Nat. Int. &NGO’S

ANDRU,
UNIVERSITIES, etc..
INESG, ENTV,PRESSE, RADIO

National Opérational
Emergency Centre (NOEC)

Tactical Level

NEGOCIATI
ON
FOR
LEVEL OFACCEPTEDRISK

ONS, SONELGAZ,
SONATRACH etc

Wilaya Disaster Management Unit

Information&
Documentation

WilayaOpérational

Operational
Level

Daira Disaster Management Unit

Daira or Baladia
Opérational
Baladia Disaster management Unit

Information&
Documentation
CentreInformation
Control

Figure 1: Structure of ANRCGCN in Algeria
182

New Technologies for Urban Safety of Mega Cities in Asia
123

APPLICATION OF POWER DEMANDCHANGES TO EVALUATE BUILDING AND
DWELLING DAMAGESDUE TO EARTHQUAKEKIMIRO MEGURO1 AND YASUNORI HADA2International Center for Urban Safety Engineering
Institute of Industrial Science, The University of Tokyo
2
Disaster Center and Human Renovation Institution
meguro@iis.u-tokyo.ac.jp
1

ABSTRACT
Early earthquake damage evaluation is very important for thedisaster-related organizations to take prompt action in order to minimize
the hazard negative impact. This paper presents a methodology to evaluate
the earthquake damage to buildings and dwellings using monitored power
supply before and after the event. The electric power demand was used toevaluate regional characteristics and a high correlation was found between
the demand changes and the earthquake damage. The proposed method
allows a feasible real-time damage evaluation methodology that can bereadily implemented with little investment and its applicability is not limitedby the weather conditions or time.
1.0 INTRODUCTION
The accurate evaluation of earthquake damage is extremely importantfor disaster related organizations to efficiently plan their actions. After the
1995 Kobe Earthquake (Great Hanshin-Awaji Earthquake or Hyogo-ken
Nambu Earthquake), several methodologies for quick disaster estimation
were developed. Fragility curves combined with strong ground motion
records as well as remote sensing techniques are among them (Noda and
Meguro, 1995, Yamazaki et al, 1998, Takashima and Hayashi, 2000,
Matsuoka et al, 2001). As an alternative to these methodologies, we propose
the monitoring of power demand variations during and after the event as ameans to evaluate earthquake damage. Power is permanently supplied to theusers, with its demand strongly reflecting the people’s response or actions.
During a disaster, the damage level of an area is directly reflected by theactivities of the people there. Therefore, the power demand after theoccurrence strongly reflects the site damage situation.
The proposed methodology has several benefits. First, there is no needto develop new facilities to implement a power demand monitoring system.
All the facilities are already available and provided by the power supply
company. Second, a real time monitoring is possible. Third, there is no needto collect a database of the structure strength characteristics or to develop
fragility curves before the event. Finally, the observation is not affected byweather conditions or time.

33
124

October 2004, Agra, India

In this paper, the feasibility of the above mentioned methodology is
explored. As a first approach, the power demand is monitored at a spatial
unit defined by the substation supply area. This unit consists of one
substation for the transformation of the power for ordinary consumers(Figure 1). At each substation, there are three transformers andapproximately 20 distribution lines. Thus, from the system point of view, it
is possible to reduce the spatial unit by monitoring the power demand at the
distribution line level. However, at the present stage, the spatial unit is givenby the substation supply area.
2.0 POWER DEMAND AND REGIONAL CHARACTERISTICS
The power demand and the substation supply area characteristics arestrongly related. Meguro et al proposed a classification of a region
according to its power demand. Four categories were defined: 1) residential
type, 2) office type, 3) industrial (factory) type, and 4) entertainment (pubsand restaurant, etc.) type. By using a stochastic analysis, typical demand
curves for each type according to the season were developed for the 23
wards of Tokyo. First, power demand characteristics in the Kobe area wereassumed to be the same as those in Tokyo and demand curves obtained inTokyo were used to calculate contribution rates of each type of demand
curves in Kobe. However, the results were not appropriate as the power
demand characteristics strongly depend on the regional characteristics.
Therefore, in this report, we calculated the typical demand curves using
power demand data in Kobe.
Power plant

Super High Voltage
Substation

Transmission line
275～500kV

Primary
substation
Intermediate
substation

Transmission line
154 kV

Transmissionline, 66 kV

Distribution line
66～154 kV
Transmissionline, 66 kV

Distribution line
22 kV

Large building

Region of
Substation

Distribution line
6.6 kV

Distributionline, 6.6 kV

Poletransformer
Drop wire
200 V

Small factory

Large factory, andrailway company
substation

Distribution
substation

Building factory

Drop wire
100/200 V

Residential
house

Drop wire
100/200 V

Small officeStore/Restaurant

Figure 1: Electric power supply system
Figure 2 shows the distribution of the substation supply areas for the
Hanshin region, which has 69 spatial units with an average area of 4.78 km2.

34

New Technologies for Urban Safety of Mega Cities in Asia
125

ICUS Report 6

2.1

Power demand database

The Kansai Power Company, which supplied power to the affectedareas during the Kobe earthquake, provided data of the power demand
before and after the earthquake. The database includes hourly records fromJanuary 9 to 24, from January 28 to February 3, i.e. approximately two
weeks after the event, and from February 18 to 24, i.e. one month after the
event.
2.2

Calculation of the typical demand curves

The substation power supply area is composed of not only one of thecategories defined before, but rather a combination of them. Thus, thepower demand at each area can be evaluated as the summation of thecontribution of each category. In order to calculate the typical demand
curves, the selected spatial unit was the substation area. In this report, weselected 69 substation areas in the affected region. The calculation details
may be found in Hada et al (2004). Figure 3 shows a comparison between
the typical load curves of the four demand areas for Tokyo and Kobe.
2.3 Calculation of the contribution rate for each substation power
supply area
Using the obtained elemental load curves, contribution rates for all
substation areas were calculated. The contribution rate is the percentage ofthe power used in an area at peak-load time due to residences, offices,
factories or restaurant consumption. Figure 4 shows a comparison between
the recorded power demand and the demand calculated using the calculationof the contribution rate. A good agreement is clear. Therefore, it can beconcluded that the nature of the substation power demand can be accurately
estimated by the contribution rate concept.
Kawanishi

Kuise
Rokko island
Port island
Tarumi
030km

Figure 2: Distribution of substation areas in Kobe

Application of Power Demand Changes to Evaluate Building and Dwelling Damages due to Earthquakes 35
126

October 2004, Agra, India
2.5

Residential (Tokyo)
Office (Tokyo)
Industrial (Tokyo)

2Entertain. (Tokyo)

Current (A)Residential (Kobe)
Office (Kobe)

1.5

Industrial (Kobe)Entertain. (Kobe）

1
0.5
0
0

4

8

12

16

20

24

N o rm alized Pow e r D em and C urve

Figure 3: Typical power demand curves for Tokyo and Kobe
1
0.9
0.8
0.7
0.6
0.5
デ ma ndR実
eal de0.4

E店
ntertainme nt

0.3

工 trialIndus

0.2

Office
オ フ

0.1
0

Re
住side ntial

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Time

Figure 4: Comparison between real power demand and simulated demandby contribution ratios
3.0 CHANGES OF THE POWER DEMAND BEFORE AND AFTERTHE KOBE EARTHQUAKE
3.1 Overview of power outage due to the Kobe earthquake and its
causesAs Figure 5 shows, due to the Kobe earthquake, 260 million
customers lost power just after the event and 169 substations including 106
stations of Kobe branch office experienced malfunction. Although it took
about one week for all the consumers to recover power supply in theaffected area, with a quick recovery response such as switching of supply
network, 80% of those substations recovered within 3 hours. Fukiai

36

New Technologies for Urban Safety of Mega Cities in Asia
127

ICUS Report 6

substation, whose malfunction time was the longest, finally recovered at
7:23 am on January 18 (about 26 hours after the earthquake). From thatpoint in time, a discussion of the power demand changes can be done.
There were about 400 thousand consumers without power even after all thesubstations’ function recovered because of damage to facilities at a level,
lower than the substation. It can be argued that the demand might beaffected by the falling of poles. This does not directly imply building
damage. However, there is a strong correlation between poles and building
damage. A collapsed pole is an indication of the severity of the earthquake.
Thus, the probability of building damage in the area next to a fallen pole isvery high.
3.2 Changes of power demand before and after the earthquake at thelevel of controlling office unit
Figure 6 shows that the power demand decreased immediately after
the earthquake. Due to the large area of the spatial unit the demand drop was
not so dramatic. The gap increases if a smaller area unit is taken into
consideration.
3.3 Power demand changes at the substation unit level
Figure 7 shows the power demand variation on the day of the event,one and two weeks after, and one month after for the 69 substations
observed in the study. Figure 7(b) shows the area where the seismic
intensity was JMA7 in magenta color. The correlation between the power
demand drop and the seismic intensity is very high.

restoration
復旧率ratio

1.0
1/18, 7:23
Recovery of power supply system

0.8

1/18, 8:00
A: 400,000

0.6

A: number of customers
without power supply

1/17, 7:30
A : 1 million
B : 680.4

B: number ofmalfunctioning stations

1/17, 5:46
A : 2.6 million
B : 68

0.2
0.0
1/17

1/18

1/19

1/20

1/21

1/22

1/23

1/24

1995

Figure 5: Electric power recovery time after the Kobe earthquake

Application of Power Demand Changes to Evaluate Building and Dwelling Damages due to Earthquakes 37
128

October 2004, Agra, India

8000
Power Supply (MWh)

7000

明石
Akashi
明石

6000

立花
Tachibana
立花

5000

伊丹
Itami
伊丹

4000

西宮
Nishinomiya
西宮

兵庫
Hyogo
兵庫

3000

三田
Sanda
三田

2000

葺合
Fukiai
葺合
洲本
Sumoto洲本

1000

データなし期間
No data0
Jan.9

Jan.16Jan.23

Jan.30

Feb.6

Feb.13

Feb.20Figure 6: Changes of electric power supply before and after the 1995
Kobe Earthquake

Zones with JMA
Intensity 7
Power supply ratio
0.0 – 0.2
0.2 – 0.4
0.4 – 0.7
0.7 – 0.9
0.9 – 1.2(a) January 17(b) January 19(d) January 31(c) January 24

Figure 7: Distribution of power supply ratio in the affected areas (on theday, one- and two-week, and one-month later the earthquake)38

New Technologies for Urban Safety of Mega Cities in Asia
129

ICUS Report 6

4.0 DISCUSSION ON THE RELATION BETWEEN POWER
DEMAND AND STRUCTURAL DAMAGE
Power demand can always be monitored. As time goes by, the peakvalue gradually increases until the original demand peak is reached. In orderto analyze the relationship between structural damage and power demand,
the ratio of power demand with respect to the original demand and thedamage ratio (collapsed or burned buildings) are plotted against each other.
Figure 8 shows the graphs corresponding to the substations where a) the
residential area component contribution is over 70%, b) the officecomponent contribution is over 30%, c) the industrial component
contribution is over 35%, and d) the entertainment component contribution
is over 20%. Each graph shows four curves corresponding to four different
times: 1) the day of the earthquake, 2) one week after, 3) two weeks after,and 4) one month after. If damage is 0%, the power demand should be
100%. On the other hand, if damage is 100%, the demand should be null.
However, it is clear that even in the cases where the damage is zero, a dropin the demand can be observed. The reason for this is that even if thedamage is small or inexistent at the spatial unit under consideration, thepeoples’ activities change due to the damage in the surrounding areas. For
instance, people cannot get to their offices or factories.
Figure 8 shows another interesting feature. In the four cases
considered the correlation between power demand and structural damage
increases as time elapses from the earthquake occurrence time. On the dayof the earthquake, the correlation is low. For instance, in the case ofresidential area, it is 0.35. This is mainly due to the presence of substations
that are not supplying energy, i.e. power supply system failure, which arenevertheless considered for the calculation of the correlation. As time passes,
the correlation dramatically increases. This allows the proposed method toachieve accuracy levels superior to other damage estimation methods.
A general trend of power demand recovery is observed for the fourcases as shown in Figure 9. Shortly after the earthquake, the areas where thedamage is minor rapidly recover to the original levels of demand. The areas
where damage is higher recover as well, but not until a significant period ofrecovery. Figure 9 depicts the mechanism of power demand recovery as afunction of the damage ratio and time elapsed from the earthquake
occurrence. At first, the regression line power demand versus the damage
ratio shifts until the original demand at the locations where damage is null isreached. After this, the regression line slowly rotates until the entire region
returns to the original demand level.

Application of Power Demand Changes to Evaluate Building and Dwelling Damages due to Earthquakes 39
130

Ratio of power supply after andbefore the event
電力需要比（地震前後）
地震前後の電力需要比

October 2004, Agra, India

1.2

y   0 . 89 x  1 . 0

Jan.17Jan.24Jan.31
Feb.21R 2  0 . 821y   1 .3 x  1 .1

0.8

R 2  0 . 86

0.6

y  1.3x  0.89
2
R  0.86

0.4

y  1.4 x  0.71

0.2

N=21

0
0

R  0.35
2

0.2
0.4
0.6
0.8
Ratio of collapsed and burned structure (low rise
residential buildings)

1

Ratio of power supply after andbefore the event(a) Residential type substation areas (Contribution rate is more than 70%)1.2

y  0.97x  0.93

Jan.17Jan.24Jan.31
Feb.21R  0.55
2

1y  1.4 x  0.92

0.8

2R  0.65

0.6

y  1.4 x  0.77

0.4

2R  0.61

0.2

y  0.91x  0.44

N=18

0
0

R 2  0.33

0.2

0.4

0.6

0.8

1

Ratio of collapsed and burned structure (low rise shops andoffice buildings)

Ratio of power supply after andbefore the event(b) Office type substation areas (Contribution rate is more than 30%)1.2

y  1.0 x  0 .97

Jan.17Jan.24Jan.31
Feb.21R 2  0 .94

1y  1.4 x  0.96
2
R  0.89

0.8
0.6

y  1.4 x  0.85
2
R  0.84

0.4
0.2

y  0.86x  0.53
2
R  0.73

N=9

0
0

0.2

0.4

0.6

0.8

1

Ratio of collapsed and burned structure (small size factorybuildings)(c) Industrial type substation areas (Contribution rate is more than 30%)

40

New Technologies for Urban Safety of Mega Cities in Asia
131

Ratio of power supply after andbefore the event

ICUS Report 6

1.2

y   1 .1 x  1 . 0

Jan.17Jan.24Jan.31
Feb.21R 2  0 . 781

y   1. 4 x  1 .0

0.8

R 2  0 .75

0.6y  1.3 x  0.87

0.4

R 2  0.75

0.2y  1.4 x  0.70

N=19

R2  0.59

0
0

0.2

0.4

0.6

0.8

1

Ratio of collapsed and burned structure (small size shops
and office buildings)(d) Entertainment type substation areas (Contribution rate is more than
20%)
Figure 8: Changes of power supply after the earthquake at substations
with different damage levels
e
k
a
u
q
y
h
l
p
t
r
p
a
u
se
e
r
eh
wt
oe
pr
o
f
of
e
b
o
i
d
t
an
Ra
r
e
t
f
a

y=ax+b1

Three months later
One month later
Two weeks later
One week later
Just after the earthquake

0

Structural damage ratio

Figure 9: Model for discussion of structural damage and power supply
changes (in case regional characteristics before and after the
event are close to each other)
5.0 CONCLUSIONSThis paper presents a new technique for structural damage estimation
based on the observation of the power demand variations. This methodology
has several advantages. First, there are no limitations for the observation of
the power demand such as weather conditions, time, etc. Second, there is noneed to prepare new facilities such as aircraft or satellites for conducting theobservation. All the required facilities are already provided by the power
supply company. Third, the data can be monitored in real time. Forth, themodel is continually updated since the power demand is continuously being
observed, i.e. immediate feedback is possible. Fifth, the proposed

Application of Power Demand Changes to Evaluate Building and Dwelling Damages due to Earthquakes 41132

October 2004, Agra, India

methodology is also useful to supervise the reconstruction progress bymonitoring the power demand recovery. Even in case a certain area changes
its type of use, i.e. from an industrial use to a residential use, the expected
power demand can be easily estimated from the model and recovery
supervision is possible.
REFERENCES
Yamazaki F., Noda S. and Meguro K. 1998. Developments of Early
Earthquake Damage Assessment Systems in Japan, Structural Safety
and Reliability. Proceedings of ICOSSAR 7, 1573-1580, Balkema.
Meguro K., Soejima M., Yamazaki F. and Katayama T. 1995. Classificationof Urban Areas by Characteristics of Power Load Curves. Proc. of 5thInternational Conference on Seismic Zonation, 60-67, Nice, France.
Matsuoka M., Yamazaki F. and Midorikawa S., 2001. Characteristics ofSatellite Optical Images in Areas Damaged by the 1995 Hyogo-ken
Nanbu Earthquake. Journal of Japan Society of Civil Engineers, 668/I54, 177-185, 2001.
Takashima M. and Hayashi H., 2000. Validation of Damaged Area
Estimation using DMSP/OLS night-time imagery, - application forMarmara earthquake in Turkey (1999) and Hanshin-Awaji earthquake
in Japan (1995). Journal of Social Safety Science, Institute of Social
Safety Science, 2, 69-78.
Noda S. and Meguro K., 1995. A New Horizon for Sophisticated Real-Time
Earthquake Engineering. Journal of Natural Disaster Science, 17(2), 1346.
Hada, Y. And Meguro K., 2004. Introduction of An Earthquake Damage
Evaluation Method For Buildings And Dwellings By Monitoring
Changes Of Power Supply. US-Japan Cooperative Research For Urban
Earthquake Disaster Mitigation Assessment Of Post Earthquake
Management Processes Using Multimedia Disaster Simulation.

42

New Technologies for Urban Safety of Mega Cities in Asia
133

INTEGRATED EARTHQUAKE SIMULATIONUSING SIMULATION AND GIS
MUNEO HORI AND KENJI OGUNI
Earthquake Research Institute, The University of Tokyo, Japan
hori@eri.u-tokyo.ac.jp
ABSTRACTThe advancement of computer technology and sciences enables us alarge-scale numerical computation. As one of such, the authors have been
simulating the whole processes of earthquake, i.e., the generation andpropagation of earthquake, the response and damage of structures, andhuman and social action against disaster. With the aid of the latest
geographical information system (GIS), a compute model can beconstructed for a city of some hundred-meter scale; a structure model is
automatically made for each building, and a suitable numerical analysis
method is applied to calculate the dynamic response of each model for agiven strong motion.
This paper presents the current state of this integrated earthquake
simulation. The simulation is controlled by a computer system which
combines numerical analysis methods and GIS. An example of a computermodel of a city is presented. Discussion is made on the usefulness of thelarge-scale simulation of the integrated earthquake simulation, in order toform a common recognition of possible earthquake hazards among citizens,government officers and earthquake engineers.
1.0 INTRODUCTION
Local government officers play a major role in promoting earthquake
disaster mitigation since they make and enforce regional mitigation plans
against a possible earthquake. For the technical point of view, the local
government officers are not in an ideal state. They are essentiallyadministrators and do not have to understand seismology and earthquake
engineering at high level. Even engineering-oriented officers do not havesufficient experiences on designing and constructing structures.
Improving the technical ability of the local government officers is an
important issue. The technical ability means correct understanding ofprediction of possible earthquake damages which is made by experts. The
uncertainty of the prediction must be grasped, and the targets are allbuildings and structures located in the city.
The technical ability must rely on a solid foundation such as
earthquake resistant design codes. The codes, however, are written for aprofessional design engineers, and local government officers have somedifficulty to read the codes; they must read the codes of various structures.
Visualization of dynamic responses of all structures located in a city helps

43
134

October 2004, Agra, India

understanding the earthquake resistant codes when the responses arecomputed by using the codes. Realizing such unified visualization of
structure responses is the primary objective of the present paper.
Unified visualization is made with the aid of an integrated earthquake
simulator (IES), a system which is aimed at simulating all processes ofearthquakes, with the aid of data stored in geographical information system(GIS); see Yang et al. (2002). Numerical analysis methods based on actual
earthquake resistant design codes are implemented in IES. An example ofunified visualization which combines all the simulation results is presented.
2.0 SYSTEM FOR UNIFIED VISUALIZATION
Realizing unified visualization is not trivial, even if it is taken for
granted that there is limitation in constructing computer models for all
structures due to lack in available data. The major difficulty is theimplementation of numerical analysis methods of various structures into one
system. To solve this difficulty, we develop a mediator, a computer agent
which automatically implements a numerical analysis method to IES.
2.1 Mediator in IES
First, we briefly explain IES (Yang et al., 2002). As mentioned, IES isa system for numerically simulating all processes of earthquake; theprocesses are basically divided into three phases, namely, the generation andpropagation of earthquake, the responses and damages of structures, and thehuman and social action against earthquake disaster. IES thus consists ofthree simulations, earthquake simulation (Ichimura and Hori, 2000),
structure response simulation and action simulation; see Fig. 1.
computer model of cityhouse

school/hospital/theatertransportation systemhigh rise building

structure response simulation

action against earthquake

earthquake
amplification

crisis managementtime

evacuation
retrofitting

propagation

recoveryfault mechanism

action simulation

earthquake simulation

Figure 1: Overview of IES.

44

New Technologies for Urban Safety of Mega Cities in Asia
135

ICUS Report 6

Major components of IES are kernel, GIS, simulation programs (SP)of structures and visualization tools. Kernel is a key component, as it
controls other components; see Fig. 2. From GIS, kernel extracts dataneeded for model construction. Providing data for model and strong groundmotion, kernel runs each SP. Kernel finally collects all simulation results
and send them to visualization tools.
Plug-in is not suitable for implementation of SP’s into IES, since it
requires a laborious task of modifying a source code of SP. As an alternative,
we adapt an agent, called a mediator, which translates all communications
between kernel and SP; see Hammer et al. (1995). The communications arefor data input, execution and result output. Thus, each mediator plays a roleof an interpreter for its supporting SP (Uhlman, 1997, Gruber 1993).
It should be emphasized that each SP needs a particular mediator.
Making a mediator requires a laborious task similar to modifying a sourcecode since SP has its own description of input/output. However, the basic
structure of all SP's is common; they are based on finite element method(FEM) which is a standard analysis method of earthquake resistant design.
In principle, therefore, it is possible to automatically make a mediator for agiven SP. In this paper, we seek to develop an artificial intelligence, called a
mediator maker, for this purpose.
2.2 Mediator maker
When viewed from the point of input and output, an FEM-based SP
basically consists of an input part and a loop part which further consists of acalculation subpart and an output subpart. The input part is literally for

input

target cit/earthquake scenario

simulation
programsimulation
programGIS
kernelsimulation
programlibraryvisualization

outputstrong ground motion distribution
structure damage
action against earthquake disasterFigure 2: Kernel of IES.

Integrated Earthquake Simulation using Simulation and GIS
136

45

October 2004, Agra, India

inputting data such as configuration, material properties and boundary
conditions. The loop part repeats calculation in the calculation subpart andoutput of temporal results in the output subpart. In view of this program
structure, we specify basic functions of a mediator in Table 1. The first fourfunctions correspond to the input part, and the sixth function is for the
output subpart. The fifth function interprets kernel's command of execution
and the seventh function is to construct files for the unified visualization.
When C++ is used, a mediator is programmed as a class and the basic
functions shown in Table 1 are written as methods of the class. Making useof succession, we can efficiently construct the class; a source class for a
mediator is pre-constructed, and a new class is construed by modifying thecontents of data and methods of the source class.
A mediator maker is an artificial intelligence program which outputs aclass of a mediator when a source code of SP is given. Making a classmeans describing the seven methods which are inherent to SP. The mediatormaker does this task through the two phases, namely, the analysis of thesource code and the construction of mediator; see Fig. 3.
In the first phase, the mediator maker generates a digested code, asimplified code which contains only input/output and loop sentences, fromthe source code of SP. When the source code is written in FORTRAN, thekey points of analyzing SP are subroutines and common memories. In
analyzing subroutines, the mediator maker finds all subroutines in thesource code, picks up input/output statements, and examines the order of the
input/output sentences and the type and format of input/output variables byconsidering mutual relations of subroutines.
Table 1: Basic functions of mediator.
basic function

content

identification of structure

identify structure and building in a target city from data
extracted from GIS

selection of SGM site

select sites where SGM is computed and inform them toearthquake simulator

acquisition of structure data

construct data files for input of SP, by extracting data from
GIS and libraryacquisition of SGM data

construct data files for SGM at sites, using results ofearthquake simulator

execution of SP analysis

run SP using data files which are constructed by mediatoracquisition of results

take results of simulation from SP, and make result files

visualization

make visualization files (VRML/POV/AVS) from result files
made by mediator
SGM: strong ground motion

In the second phase, the mediator maker analyzes the digested codeand describes the seven methods of the mediator class. Since the digested
code mainly consists of input/output and loop sentences, the major tasks are1) analysis of input/output, 2) analysis of loop and condition and 3)

46

New Technologies for Urban Safety of Mega Cities in Asia
137

ICUS Report 6presumption of variables which are used in input/output or loop andcondition. The presumption of variables is important in describing themethods since the mediator makers match these variables with variables
which are used in the original class in succeeding it to a new class.
It should be emphasized that constructing a robust artificial
intelligence program is extremely difficult. The current mediator maker is
not complete, as it requires some man power in describing a class for a
mediator. However, it saves man power to some extent since the program
structure of a source code is analyzed and some input/output variables are
identified.
3.0 EXAMPLE OF UNIFIED VISUALIZATIONWith the aid of the mediators which are produced by the mediatormaker, IES constructs a virtual city (VC) as a computer model for an
artificial city of 300x300[m] area; see Hirose et al. (1999) for a computermodel of city. A small GIS is constructed for this city, such that data toconstruct computer models for the underground and structures are stored.
The underground, up to depth of 40[m], consists of three distinct layers, andthere are four gas pipe lines, five concrete piers, seven steel piers of two
kinds and four ground molds. A schematic view of VC is presented in Fig 4.
This figure is a result of visualization; IES automatically generates the static
image of VC and each structure within VC as well as dynamic images(animation) of VC as for unified visualization.
The second phase of construction of mediator is not trivial, due to thedifficulty in presuming variable. We seek to presume the meaning of somevariables which are commonly used in FEM-based SP, namely, the node
number, the element number and the time increment number. Thesevariables are input in the beginning of the input part and used in the loop
part, and the mediator maker seeks to find them as follows:source codes

analysis of source codesubroutinecommon memory
digested code

construction of mediatoranalysis of I/O
analysis of loop andcondition

prediction of variable

code for mediator

Figure 3: Two phases of mediator maker.

Integrated Earthquake Simulation using Simulation and GIS
138

47

October 2004, Agra, India






the node number as a variable which controls the iteration of the
input part and of the output subpart;the element number as a variable which controls the iteration of
the output subpart;the time increment number as a variables which control theiteration of the loop part.

As an example, the frequency of all variables appearing in the digested
code are shown in Fig. 6 for a digested code of concrete pier; read/write
means input/output, and LL means the loop level (LL=0 or =1 is out of loop
sentences or in the first nest of loop sentences). As is seen, variables INODE,
IMEM, IJK are presumed as the node number, the element number and thetime increment number, which is correct presumption.
Examples of the unified visualization is shown in Fig. 5; a halfsinusoidal wave of amplitude 10[cm] and period 1.0[sec] is input at the
bedrock mass, and figures are snapshots of bird-views of VC every 0.2[sec].
The displacement of structures is magnified by 10 times, and the norm isindicated by color. As expected, structures of the identical configuration andmaterial properties have different responses since strong ground motion
input to them is not the same due to the difference in local ground structures
which results in different amplification of earthquake; see ground molds.
Structures of different kinds have responses which is mainly governed by
the natural frequency; for instance, concrete and steel piers located at thecenter of VC cause has large contrast in amplitude of displacement, and the
maximum displacement of the concrete pier is just 20% of that of the steelpier.

soil layer

concrete pierground moldsteel piergas pipe line

Figure 4: Static view of VC.48

New Technologies for Urban Safety of Mega Cities in Asia
139

ICUS Report 6It should be emphasized that SP's implemented into IES have beenused to analyze dynamic non-linear responses of a structure for the research
purpose. Hence, high reliability can be expected. The unified visualizationof earthquake disaster which may happen in a city surely contributes to theimprovement of the engineering ability of local government officers since it
provides a vivid image of the disaster. While more realistic visualization
will be needed, the unified visualization of quantitative information of thestructure damages which are simulated by reliable numerical analysis
methods results in making more efficient mitigation plans.

Figure 5: Example of unified visualization.

Integrated Earthquake Simulation using Simulation and GIS
14049

October 2004, Agra, India


30
25
20

write/LL=1

15

write/LL=010
50read/LL=0
IMEM

INODE

MX

KFCS

KSCS

KINDS

NAXF

IDEFO

IABAN

IJK

Figure 6: Frequency of variables at different loop level;
frequency is counted by mediator maker.

4.0 CONCLUDING REMAKRSWith the aid of the mediator and mediator maker, some SP’s ofanalyzing dynamic structure response, which have been developed
according to the earthquake resistant design codes, are implemented into
IES. An example of the unified visualization is presented for an artificial
city; it provides reliable images of possible damages of structures within thecity. This example suggests the usefulness of IES that combines GIS andsimulations for the unified visualization. The system of IES will be being
improved as well as the mediator maker such that other SP’s can be
implemented into IES more freely.
REFERENCES
Gruber, T. R., 1993. A translation approach to portable ontology
specification, Knowledge. Acquisition, 5, 2, 199-220.
Hammer, J., Gracia-Monlina, H., Ireland, K., Papakonstantinou, Y., Uhlman,
J. D. and Widom, J., 1995. Information translation, mediation, andmosaic-based browsing in the TSIMMIS system. Exhibits Program of
the Proceedings of the ACM SIGMOD International conference on
Management of Data, 483.
Hirose, M., Tanikawa, T. and Endo, T., 1999. Building a virtual world fromthe real world. Mixed Reality - Merging Real and Virtual Worlds (ed.
by Ohta, Y and Tamura, H.), Springer-Verlag, 183-197.
Ichimura, T. and Hori, M.. 2000. Macro-micro analysis for prediction ofstrong motion distribution in metropolis. J. Struct. Mech. Earthquake
Eng., JSCE, 654/I-52, 51-61.
Uhlman, J. D., 1997. Information Integration Using Logical Views. Proc.
ICD'97, Springer LNCS 1186, 19-40.
Yang, F., Ichimura, T. and Hori, M., 2002. Earthquake simulation in virtual
metropolis using strong Motion simulator and Geographic Information
System. Journal of Applied Mechanics, JSCE, 5, 527-534.

50

New Technologies for Urban Safety of Mega Cities in Asia
141

UNDERSTANDING THE SEISMIC
SOURCES IN INDIA: STRATEGIES FORSEISMIC HAZARD REDUCTION
KUSALA RAJENDRAN AND C.P. RAJENDRAN
Centre for Earth Science Studies, Trivandrum, India.
kusala@seires.net
ABSTRACT
Seismic sources in the Indian subcontinent display varying
characteristics, in their styles of deformation to earthquake recurrence.
These sources, capable of generating moderate, large and greatearthquakes occur in the interplate collision zone (Himalaya), ancient rift
systems (Narmada, Kachchh) and unrifted crust (Killari) and the uplifted
plateau (Shillong). Following are some of the key questions concerning theseismic hazard associated with these sources: Which faults are likely togenerate damaging earthquakes in the near future? What is the maximum
magnitude expected? How frequently do they generate earthquakes? Whatis the nature of ground acceleration and site amplification in these regions?
In this paper, we address some of these questions in the context of someselected seismic sources in India (Killari, Jabalpur, Kachchh), that havegenerated moderate to large earthquakes in the recent times. The Killari
earthquake of 1993 (M 6.3) occurred in a region of negligible backgroundseismicity, considered as the zone of least seismic risk. The shallow sourceand site-specific amplification, together with the style of construction
contributed to the severity of damage at this location. Paleoseismologicalinvestigations in the rupture zone suggested that the past earthquake in thesame source may have occurred ~20000 years before present. The Kachchhseismic source presents a different picture where large earthquakes recurduring shorter intervals of time (100s of years, as against 1000s at Killari).
For example, the 1819 source appears to have generated a similarearthquake about 1000 years ago. Site amplification of energy and soilliquefaction, affecting locations as far as 150 km from the source, areconsidered major causes for the severity of damage, apart from theinadequate design of structures. Our studies have revealed existence ofmultiple sources in the Kachchh region, but their past histories remain
largely unknown. We also present observations from the source zone of thegreat 1897 Shillong (Assam) earthquake, where we have dated the pastearthquake in the same source as about 1200 years before present. Our
study suggests that the seismogenic processes in the Shillong Plateau varyfrom that of the Himalaya and consequently, the hazard assessment in thisregion must consider these issues.

1.0 INTRODUCTION
Hazard evaluation and mitigation measures such as developing
appropriate design practices call for a reasonably good understanding of the51
142

October 2004, Agra, Indianature of earthquake sources. This understanding must include not only theknowledge about the location, size and potential (size and frequency, forexample) of the structures concerned, but also the site-specificcharacteristics of damage (liquefaction potential, site amplification etc.).
Attempts to assess the seismogenic potential of a fault based on its recent
and historic activities reveal their histories during a small segment of time
only, perhaps too short, compared to the interseismic interval. For example,
instrumental data are available only for a few decades and the historic
documents in most regions extent only to a few hundreds of years.
Techniques such as archeo and plaeoseismology are often used toreconstruct the histories of such faults (see McCalpin, 1995). Knowing thetiming of the past earthquakes often helps to obtain some handle on the
future activity on the same fault. Obviously such information provide basic
inputs for hazard assessment as well as information required in the planningof critical facilities such as nuclear power plants, in the proximity ofseismogenic structures. These faults may not be active at the present time,
but admittedly, the short period for which historic information is available
does not really represent the seismogenic status of such structures. Ability to
map a fault and develop its past histories may vary from one location to theother, based on the nature of activity on the fault (size and frequency ofearthquakes, for example) as well as the site-specific nature of deformation.
For example, in regions where large earthquakes have occurred in the
recent/historic past and where the geological conditions are favorable for thegeneration and preservation of primary and secondary features, such studies
are much easier, compared to regions of infrequent, low/moderate seismicity
that does not lead to significant fault-related features such as fault scarps
and offsets, liquefaction features etc.
Five damaging earthquakes occurred in India during the last ten years,
causing substantial loss of life and damage to property. These were at
Uttarkashi (1991, mb 6.5); Killari (1993, Mw 6.2); Jabalpur (1997, Mw 5.8);
Chamoli (1999, mb 6.3) and Bhuj (2001, Mw 7.7). Of these, the Chamoli andUttarkashi earthquakes occurred in the Himalaya and these are not discussed
in this paper. The other three events occurred in the peninsular India (Fig. 1),
a part of the Stable Continental Region (SCR), characterized by slow
deformation and low seismic productivity. In this paper we discuss thecharacteristics of these three seismic sources. We also present someobservations about the source of the great 1897 Shillong earthquake in the
NE India.
The Killari earthquake occurred in a region that had not experienced
any notable seismicity in the past and was regarded to be of low seismic risk.
This earthquake came as a total surprise and as a grim reminder that adamaging SCR earthquake can occur even at the least expected location. On
the contrary, the 2001 Bhuj event occurred in a region that has experienced
previous large earthquakes, the most notable being the one in 1819, a classic
example of SCR-seismicity associated with passive rifts. It had caused morethan 2000 deaths and brought about permanent changes to the landscape ofthe region. In comparison, to Killari and Bhuj earthquakes, the Jabalpur
presents a different case; it was spatially coincident with the ENE-WSW

52

New Technologies for Urban Safety of Mega Cities in Asia
143

ICUS Report 6trending Narmada-Son lineament, which occasionally generates lowmoderate earthquakes. These earthquakes are associated with an ancient rift
system that closed subsequent to the Himalayan collision (see Rajendranand Rajendran 1999a and references therein). All of these earthquakes havebeen studied in detail and a large volume of information is available. The
purpose of this paper is to use these examples to illustrate how moderate orlarge earthquakes in diverse tectonic settings can differ in theircharacteristics. Observations presented in this paper illustrate the need toadopt different strategies for hazard reduction, considering the diverse
nature of these sources.
70°
24°

72°

74°

76°

78°

22°N
1869, 1872
IV, III

ad a
Narm

22°

80°

1819
2001
r
Rive

Jabalpur

20

NSL

Tapti R.

1757, V18
1764, VII20°
Deccan Traps
18°

1201
1942, ,IV
1953, IV
Ter ~450A.D
1993, Killari
1955, IV

1896

Killari16

1865, III

1886
Historic earthquakes

1843, VII

Ancient earthquakes

14

16°

1934, III
1861, 1862
IV

74

75

76

77

78°E

Figure 1: Map of western India Figure 2: Historic seismicity in theshowing earthquakes discussed in the Killari region. The shaded region
text
indicates
theNW
corridordiscussed in the text.
2.0 THE 1993 EARTHQUAKE AT KILLARI
The Killari earthquake occurred in the eastern margin of the Deccan
Plateau, formed by Late Cretaceous-Eocene basalt flows (Fig. 1). The
earthquake, which nucleated at shallow depth (5 km), was associated withhundreds of aftershocks (Kayal et al., 1996). Killari falls in zone I of India’s
seismic zonation map; this region has not experienced any significant
earthquakes in the historic past and it was not considered as a potential site
for a future damaging earthquake. Consequently, the level of awareness andpreparedness, particularly in terms of construction practices was also very
poor, a situation that increased the damages manifold. The generally low
background seismicity, together with the perceived stability of the region
made this earthquake appear as a total surprise. Its occurrence triggered
many questions on the mechanism of SCR earthquakes. Some of these
pertinent questions are: Do the SCR source zones share common
characteristics? Are these earthquakes random or periodic? Do they repeat
at the same source? Many of these questions remain to be answered fully,
but the studies that followed the Killari earthquake provided a variety of
data, helpful to address some of these questions.

Understanding the Seismic Sources in India: Strategies for Seismic Hazard Reduction
144

53

October 2004, Agra, India


Relatively inactive areas such as the source zones of the Killari
earthquake seldom attract the attention of earthquake scientists. Thus, it is
only after an earthquake actually strikes at such a location that one tries to
examine whatever scanty data that may be available. We examined theearthquake catalogues for peninsular India (Rao and Rao, 1984), whichindicate no earthquake of M > 6 from this region during the recent or
historic times (~ 800 years). The background seismicity associated with theKillari source seems to compare with those in other cratons, such as
Australia. Interestingly, the locations of historic earthquakes during AD
1201-1960 (Geological Survey of India) appear to be mostly confined to a
400 km-long, NW corridor, passing through Killari (Fig. 2).
Spatial correlation of this corridor of activity with a structure inferredfrom a variety of field evidence as well as the fault plane solution of themain event suggested reactivation of a NW oriented fault (Rajendran et al.,1996). The 3-D distribution of aftershocks suggests that the earthquake
originated at the intersection of the NW and EW oriented faults (Kayal et al.,1996). These observations suggest localization of strain build up, which
may develop as future locations of earthquakes. Thus, the Killari-type
earthquakes seem to occur in certain locations within the stable region,
where the conditions for the localization and build up of stress are favorable.
The next important question is if the Killari earthquake was a temporally
isolated event or if any previous earthquakes have occurred on the samestructure. We address this question through paleoseismologicalinvestigations in the rupture zone of the 1993 earthquake.
The Killari earthquake generated a small scarp (a few centimeters toabout 80 cm) along a 1-km-long discontinuous rupture. Since very few SCR
earthquakes are associated with surface ruptures, this earthquake presented aunique case for detailed field investigations. The deformation zone at Killari
has since then been the site of many studies including trenching, deep
drilling and other studies (Seeber et al., 1996; Rajendran et al., 1996 andGupta et al., 1999). Initial studies in the rupture zone were concerned
primarily with obtaining evidence for past earthquakes that may haveoccurred in the same source. Early shallow trenching suggested that the1993 earthquake originated on a new fault (Seeber et al., 1996). However,deep trenches cut across the rupture zone exposed a wide impact zone
comprising of minute fragments of rocks and grounded mass with yellowish
clay, which was interpreted as evidence of previous movement (Rajendran
et al., 1996). Indications of thrusting observed in the lateritized profile
overlying the basalt flows were also considered as additional evidence for
deformation in the layers basalt. Preliminary analysis based dating of gouge(based on thermo luminescence technique, TL) from the impact zone
suggests an age of 18-20 ka for the penultimate earthquake at this source(Rajendran and Rajendran, 1999b). This appears to be in the range of repeat
intervals observed for other cratonic regions, such as Australia. Evidence forprevious movement has been obtained also from deep drilling in the rupturezone. A maximum displacement of about 6 m, observed in the deeper basalt
layers is suggested as evidence for repeated reactivation. On a first
approximation, this should suggest occurrence of at least six events

54

New Technologies for Urban Safety of Mega Cities in Asia
145

ICUS Report 6
(assuming constant slip) subsequent to the last episode of basalt flow,
suggesting interseismic intervals of the order of several 1000s of years, assuggested also by the TL data.
Search for paleoearthquakes in the vicinity of Killari led to theidentification a deformation event dating to AD 350-450, at a location
known as Ter, about 40 km northwest of Killari. Evidence for theoccurrence of another earthquake in the NW corridor (Fig. 2) defined byhistoric earthquakes as well as structural trend is a possible indication that
other discrete parts of this pre-existing weak zone may have beenreactivated in different segments of time. We have no data on the older
earthquakes on the Ter fault, but going by the example of Killari, it isreasonable to assume that the next event on this part of the fault may bethousands of years away.
The important question concerning the Killari source is whether there
are other discrete segments of this fault that might be the next candidate for
rupture? Because such structures seem hidden beneath the basalt and they
are not expressed by any recent activity, will some of them spring anothersurprise? The biggest lesson to be learned from this earthquake is thatseismic hazard assessment in the intracratonic regions must take into
account, even the less prominent and perhaps unexposed faults. These may
not be active in the current time window, but without an understanding of
their past histories, hazard evaluation will not be complete. How did an M
6.3 earthquake lead to such total devastation in a few villages in theimmediate vicinity of the epicentre? Apart from the poor style of rural
construction, one aspect that compounded the damage is probably the
amplification of seismic energy at the rock-soil interface. The thin soil
profile (a few meteres) overlying the basement rock appears to haveprovided an excellent medium for amplification of seismic energy as thewaves passed from the high velocity basement to low velocity soil. The
layered structure of the soil also provided ideal conditions for the generationof multiples. We believe that this peculiar site-specific behavior, together
with the non-engineered nature of the rural houses were prime factors in theseverity of damage at Killari.
3.0 THE 1997 EARTHQUAKE AT JABALPUR
The Mw 5.8 earthquake near Jabalpur is spatially coincident with the
ENE-WSW trending Narmada-Son rift (Fig 3). This earthquake killed 48
people and left many injured. Several thousands of houses were partially orcompletely damaged. The occurrence of this earthquake has perhaps guided
to the conception and implementation of major project on microzonation of
Jabalpur, which will put together a variety of information to prepare hazard
zonation maps. Geological and geophysical surveys have unequivocallyestablished this structure as deep fault zone, cutting across the entire breadthof central India. This structure is also associated with low-moderate
seismicity and at least 4 earthquakes of magnitude > 5 have occurred in thisregion.

Understanding the Seismic Sources in India: Strategies for Seismic Hazard Reduction
146

55

October 2004, Agra, India

72

74

76

78

80

82° E

24°N
JabalpurNarmada R.
Broach1970 (5.4)
1938 (6.3)

Gulf of Cam
bay

22

20
0

1927 (6.5)

1957 (5.4)

Tapti R.

M<4
M>4

100km

18

Figure 3: Historic and recent earthquakes in the Narmada rift region.
The 1997 Jabalpur earthquake is indicated by a star.
In comparison to other shield-related earthquakes, those associatedwith ancient rift systems seem to be originating at mid-crustal or lower
crustal depths. The Jabalpur earthquake also falls in this category, with its
focus at a depth of 36 km. Another interesting aspect is the limited
aftershock activity (see Rajendran and Rajendran, 1999a for details). While
the Killari earthquake was followed by hundreds of aftershocks, theJabalpur earthquake had only a few aftershocks. In terms of seismic hazard
assessment, the nature of aftershock productivity is an importantconsideration, because a large number of aftershocks following a mainshock
can lead to failure of structures already weakened by the main shock.
4.0 SEISMIC SOURCES IN THE KACHCHH RIFT
4.1 Allah bund: 1819
The 1819 earthquake (Mw 7.5) occurred on the northwestern flank of
the Kachchh basin in NW India, a known seismic source in the Indian SCR(Fig. 4). The damage caused by this earthquake at Bhuj, located about 150
km southwest of its epicentral region is quite revealing of the severity of thisearthquake. Nearly 7000 houses were destroyed in this town, killing morethan 1150 people. The shock was felt in far away cities such as Ahmedabad(about 300 km from the epicentre) where a 400-year-old mosque wasdamaged (Oldham, 1926). This earthquake generated one of the mostdramatic of the surface deformation features formed by an SCR earthquakea nearly 60 km-long, warped zone with an average elevation of about 2.5 mhigh, popularly known as the Allah Bund. It caused widespread liquefaction
in a large area, the farthest documented effect being at Porbandar, about 250
km south of its source zone (Oldham, 1926). Liquefaction of sediments
appears to be the major cause for the submergence of the Sindri Fort,
located about 8 km south of the Allah Bund (Rajendran and Rajendran,2001). Damage from the 1819 earthquake suggested that a similarearthquake can affect distant cities such as Ahmedabad.

56

New Technologies for Urban Safety of Mega Cities in Asia
147

ICUS Report 6

89

0

25 N
bay

1819, M7.5
Ka
chc
hh
Rif
t

23

Gulf of Kachchh

2001, M7.7
1956
M6.1

K

iaw
a th

.
ar F

26

68

69

70

71

72

96

97

0

98 E

Sadiya1697
Brahmaputra valley

TezpurGauhati

24
23

Dauki Fault

35°N
Lahore30°

6795

Shillong
25

Gulf of Cambay

100 km

94

1950

0

73 E 22

05
19

21

93

Himalaya

1897

22

92

27

DholkaBet Dwarka

91

28

R if tAllah bund

24

90

290
N

C am

AD 893

TIBETAN

PLATEAU1934
New Delhi
80°
75°

85°

50
19

Shillong
1897
90°E

Figure 4: Map of Kachchh region Figure 5: Map of NE India showing
showing the rifts, earthquakes and location of the 1897 Shillong
earthquake. Inset shows the rupture
locations discussed in the text.
areas of the 1905, 1934 and 1950
earthquakes. See text for discussion
With the experience of a large historic earthquake, we explored thisregion to understand its past activity. Paleoseismic investigations in the1819 epicentral area suggested occurrence of another earthquake about 1000
years ago. By sifting through some historic documents, we could gather
supplementary evidence suggesting that this event occurred in A.D. 893,
providing additional constraints to the paleoseismic evidence. This is thefirst example from India, for constraining the date of past earthquake, in thesource zone of a large earthquake, using paleoseismological as well as
historical data (Rajendran and Rajendran, 2001, 2002).
Although our investigations helped to estimate the timing of thepenultimate earthquake in the 1819 source, this information is still
inadequate to suggest a recurrence interval for large earthquakes. One
reasonable conclusion that we could derive is that the 1819 source has thepotential to generate large earthquakes over a period of 1000 years. The
occurrence of the 2001 Bhuj earthquake on an independent fault within therift illustrated that earthquakes in the Kachchh rift are not just restricted to
the Allah Bund source. The natural question that followed is whether there
are other unknown sources, waiting to generate future large earthquakes.
Paleoseismic data, although scanty, suggest the possibility for otherpotential sources, but their seismic histories remain to be explored.
4.2 Bhuj: 2001
The 2001 source was not known to be associated with any previous
large historical earthquakes, the only significant event in this region being
the 1956 Anjar earthquake (Fig. 4). Compared to the 1819 earthquake, thesurface effects of the 2001 earthquake were less dramatic in that it was not
associated with any primary surface folding or rupture. However, thisearthquake generated sandblows, ground fissures, minor strike-slip faults,
linear mounds and small thrust scarps. Ground failure features include
widespread liquefaction, lateral spreads and gas ejection, which were more
intense within a radius of 50 km around the epicenter (Wesnousky et al.,Understanding the Seismic Sources in India: Strategies for Seismic Hazard Reduction
148

57

October 2004, Agra, India
2001). The depth distribution of aftershocks suggested that the earthquake
occurred on a fault that dips 50° toward the south, but the projection of thisplane does not match with any mapped faults in the area. The depth range ofaftershocks is from 10-35 km and the fact that there no shallower events is
consistent with the observation that there was no obvious main fault rupture
for this earthquake. Based on the overall style of deformation, lack of a
primary surface rupture and absence of aftershock activity at depths
shallower than 10 km, the causative fault is considered as a blind thrust.
Compared to fault that are exposed and with well-expressedgeomorphic features, possibly also associated with some discernible patternof recent seismcity, blind thrusts pause more threat because of the lack of
information on their existence. This situation can lead to severe earthquakerelated damage at the least expected locations. The occurrence of a large
earthquake on a hitherto unknown fault in the Kachchh rift pointed to theunderestimation of seismic hazard associated with this structure. Whether
this source has a similar history as the 1819 source and if there were moresuch unknown faults waiting to fail, became issues of immediate concern.
The Bhuj earthquake caused widespread liquefaction and related
features in a large area. However, trenching in a few large craters in theepicentral area did not expose any significant evidence of older liquefaction.
One example where a 2001 sand dike has cut an older sandblow wasobserved in a river valley at Dholka, near Ahmedabad, about 250 km southof the 2001 epicenter (see Fig. 4 for location). This trench provided a single
TL age constraint of 2948±295 yr B.P., for the older dike (Rajendran et al.,2002). Causative source of this earthquake remains unknown, but the nearly
3000-year-long interval between the liquefaction events suggests two
possibilities: one, that no earthquake may have affected this region during
the intervening period and two, that the sandblows that formed during thisperiod may have been eroded or disturbed by anthropogenic activities.
Further work in this region has exposed more features belonging to the same
vintage and we are inclined to believe that there are no missing events
between the 3000-year-old and the 2001 earthquakes that have affected thisregion.
The history of damage to the ancient Harappan settlement at (B.C.
2600 to B.C. 1600), located about 60 km north of the 2001 epicentre, offer
additional constraints on the timing of the past earthquakes. Although thisstructure suffered only minor damages from the 2001 earthquake (somebricks at the entrance had fallen off), subtle evidence of a previous
deformation event, in the form of a flexure is preserved on the brick wall in
the central part of the fort. The 1819 earthquake did not cause any damage
to this structure; paleoseismic investigations in this area did not expose any
major features that could be related to that earthquake. However, this 4000year fort underwent some significant repairs during the closing decades ofStage III of the settlement (B.C. 2500- B.C. 2200), possibly due to an
earthquake (Joshi and Bisht, 1994). No major repair work is reported tohave taken place since Stage III of this settlement. The question to beresolved is whether an older earthquake at the Bhuj source could have58

New Technologies for Urban Safety of Mega Cities in Asia
149

ICUS Report 6caused this damage, requiring major reconstruction. Could the same
earthquake have caused the damage at Dholavira and the liquefaction at
Dholka? The underlying assumption here is that we know only about the
Bhuj and Allah Bund sources, but this may not be the true situation.
Paleoseismic studies suggest the possibility for a third source in the vicinityof Bet Dwarka where the last earthquake seems to have occurred around2000 years ago.
4.3 A third source near Bet Dwarka?
Bet Dwarka, a coastal island on the coast of Gulf of Kachchh, is
known to have hosted human settlements dating back to more than 3000
years, this site offers opportunity to use archeological data in combination
with paleoseismic evidence (see Fig. 4 for location). In one of the trenches
excavated here, we observed a paleoliquefaction feature, which shares mostattributes of seismically induced structures. Charcoal from the liquefied
layer was dated to be 1859±60 yr B.P. (cal. A.D. 25-A.D. 328); thesediment immediately overlying this sandblow was dated as 1980±40 yr B.P.
(cal. B.C. 50 - A.D. 100). We have proposed that an earthquake may haveaffected this area ~ 2000 years ago, but its exact source remains to beconstrained (Rajendran et al. 2003). The age data from Bet Dwarka does
not compare with the data obtained from other sites and the obvious
question is if we are dealing with a totally independent source. If theseobservations are correct, the Kachchh region features multiple sources
which may show varying pattern of recurrence. We do not have a precise
chronology on their past activities; nor do we know about their locations.
However, going by the experience of the 1819 and 2001 earthquakes, one
thing is very evident. Large earthquakes in this region tend to cause damage
even at distant locations, due to liquefaction, lateral spreading and site
amplification. The large range of distances in which liquefaction features
are generated is itself a problem in pinpointing the exact source zones. But
the knowledge that many seismic sources exist and that future earthquakes
in each of these regions may affect far away locations should be an
important criterion in the seismic hazard assessment of this region.
5.0 1897 SHILLONG EARTHQUAKEOne of the largest earthquakes in the modern history, the mechanismof the 1897 Shillong (Assam) earthquake is still debated (see Fig. 5). Whilesome workers relate it to the Himalayan fault system (Seeber andArmbruster, 1981 for example), there are other workers that view it asrelated to an independent source related to the Shillong Plateau (Bilham andEngland, 2001; Rajendran et al., 2004). Two issues regarding thisearthquake remain poorly understood. One concerns the geometry of thefault and its relation to the Shilong Plateau and two, the age of the pastearthquake in detail. Rajendran et al. (2004) have addressed these issues indetail and here we reproduced some of their important observations.
The 1897 earthquake generated massive liquefaction in the
meizoseismal area, particularly within the Brahmaputra Valley (Oldham,

Understanding the Seismic Sources in India: Strategies for Seismic Hazard Reduction
150

59

October 2004, Agra, India
1899). We believe that identifying older generation liquefaction features anddating them would provide constraints on the previous earthquakes in thisregion. Previous workers conducted paleoliquefaction studies along theKrishnai and Chedrang Rivers, a region known for the 1897 coseismic
secondary rupture (Sukhija et al., 1999a and b). These studies indicatedevidence for at least two older earthquakes during A.D. 1450-1650 and A.D.
700-1050. Our re-evaluation of the published data suggests that theliquefaction features identified in this area can also be placed in two groups,
based on their relative sizes. While the younger features (A.D. 1450-1650)
are characterized by ~10 cm wide vents, the width of the older vents (A.D.
700-1050) is ≥50 cm. We conducted more excavations and came acrossmultiple liquefactions- from 1897 and its predecessor. We highlight here thesalient features of some interesting sedimentary features, exposed at twosites in the epicentral area (see Rajendran et al., 2004 for details).
Our observations data suggest that the penultimate earthquake in thisregion may have occurred between 125080 yr B.P. and 250175 yr B.P. In
a region where history stretches to periods far beyond the probable timing of
the penultimate earthquake, chronological constraints can be obtained also
from monuments and other heritage structures. A catalogue of ancientmonuments indicates that ruins of almost all of the stone temples discoveredfrom various parts of the Brahmaputra valley belong to c. 9-10th century
A.D. Historical data also reveal that during A.D. 9th –11th century, there wasa wave of reconstruction activity in Assam (see Barua, 1966). Later
generation construction in the contemporary style and inscriptions on someof these temples testify to their rebuilding. These reconstructions seem tohave followed a massive destruction and the timing is in agreement withthat of the large earthquake (~1200 yr B.P) inferred from thepaleoliquefaction studies, discussed earlier.
Rajendran et al., (2004) made to important observations from the pointof view of hazard evaluation in this region. Seeber and Armbruster (1981)
proposed that the 1897 earthquake ruptured a 550-km-long segment of theHimalaya, filling the gap between the rupture zones of the great 1934 and1950 earthquakes (see Fig 5, inset). Following this argument, it has beensuggested that the 1897 earthquake has actually lowered the potential for alarge earthquake in the Himalaya. If indeed the mechanism of the 1897
earthquake is unrelated to the thin-skinned tectonics of the Himalaya, theseismogenic processes and therefore the recurrence of earthquakes in the
Shillong region will be independent of the Himalaya. In this scenario, thehazard assessment of the Shillong Plateau needs a different approach. The
second issue concerns the potential of the Dauki fault (the southernboundary fault) which has not broken at least for the last 1000 years. The
threats from the faults bordering the plateau remain underestimated; so also
the hazard associated with the unbroken segment of the Himalaya, between
the 1934 and 1950 ruptures.

60

New Technologies for Urban Safety of Mega Cities in Asia
151

ICUS Report 6


6.0 DISCUSSION
The earthquakes at Kachchh and Killari may be considered as
representative examples of two distinct types of SCR earthquakes. The
former occurred in a pericontinental rift, where large earthquakes seem torecur during short intervals of time where as the latter originated in theshallow and un-rifted part of the SCR crust. The Jabalpur earthquake issomewhat different because of its association with a well-definedcontinental structure, known to have generated earthquakes in the past.
Going by the nature of this structure, it appears that earthquakes ofmagnitude around 6 can be expected on any part of this structure and hazard
assessment strategies must consider this possibility. The Kachchh seismiczone shares characteristics of other well-known sources associated withfailed rifts elsewhere. For example, the recurrence period of the Kachchhtype earthquakes may be of the order of only 100s of years.
The current picture of the seismic history of the Kachchh region isvery sketchy. Limited paleoseismic investigations in the region suggest
existence of multiple sources associated with different fault systems.
Seismic histories of these sources are barely known- two events separated
by an interval of about 1000 years are known from the Allah Bund fault, but
this data is insufficient to suggest a recurrence model. The Bhuj source,
however is associated with a different recurrence rate, it does not seem to begenerating large earthquakes in the same way as the 1819 source. The
timing of the penultimate earthquake in the 2001 source is yet to beconstrained and only after we gather more data, a comparison can be madewith the 1819 source. Occurrence of another sandblow, belonging to anindependent age bracket (2000 yrs), in the trench at Bet Dwarka brings up
the possibility of a third source, whose location is not known. We need toconstrain the sources of these earthquakes and develop better age constraints
and this will be the focus of our future studies.
Hazard evaluation (which must start with estimation of timing,
location and size of future earthquakes) is not a simple task, particularly inregions where multiple sources with complex seem to exist. In addition to
the inherent uncertainties originating from the complexities of the source
zone, what makes it more difficult at Kachchh is the lack of sufficient data.
That some of the potential structures in this region remain hidden beneaththe thick sediment deposits adds a more difficult dimension to this problem.
A more or less complete picture of the active faults and their earthquake
histories, quantification of strain using GPS-based observations are some of
the important tasks to be completed. The investigations at Kachchh are only
beginning and only through a concerted effort to combine geologicalobservations with seismic reflection and GPS data, can we present a clearer
picture of the seismic hazard associated with this important seismogenic
source.
The Killari-type earthquakes in the unrifted crust may be considered as
an outcome of slow tectonic processes, and by the very nature of thatdefinition, earthquakes are expected to repeat only during much longer

Understanding the Seismic Sources in India: Strategies for Seismic Hazard Reduction
152

61

October 2004, Agra, India
intervals of time, compared to rift-type earthquakes. With its shallow focal
depth, abundance in aftershock activity and subdued neotectonic
expressions of the source zone, the Killari earthquake is comparable totypical SCR events in the Australian shield. Seismic hazard assessment of
SCR regions is complicated also because of the incompleteness in data. In
the absence of high quality data from each of the SCRs, assessment of theseismogenic processes may have to rely also on data from analogous
settings elsewhere. As more data are generated from various source regions,
it may be possible to identify analogies in their characteristic sizes, patternsof recurrence and deformation mechanisms.
Hazard evaluation must essentially combine a variety of information
starting from details of active faults, site characteristics as well as
population centres, life-lines etc., using latest tools such as the GIS.
Geological and paleoseismological data can provide information on thelocation and past activities associated with some of the seismic sources.
These include dimensions of the fault and expected style of deformation;
they would also provide some estimates on the locations and sizes of pastearthquakes and also identify regions of highest liquefaction potential. The
most important input to this data base must come from ground accelerationand geotechnical studies. This is one area that requires more efforts. As
more of such data become available, hazard maps indicating theprobabilities of ground shaking can be prepared. Clearly, strategies to befollowed in Kachchh region are different from that at Killari or Jabalpur, as
has been demonstrated in this paper. Similarly, the hazard caused by the
1897-type earthquakes, associated with structures that are not part of theHimalaya may need re-evaluation. The important task right now is toexpand the data base on the nature and history of active faults so thatappropriate hazard assessment scenarios can be developed, for each region.
Paleoseismological studies being carried out in the known sources ofearthquakes is a step in that direction.
REFERENCES
Barua, R.K.L., 1966. Early history of Kamarupa, Lawyers's Book Stall,
Gauhati, Assam, 234p.
Bilham, R., and England, P., 2001. Plateau 'pop-up' in the great 1897 Assamearthquake, Nature, 410, 806-809.
Gupta, H.K., Rao, R.U.M., Srinivasan, R., Rao, G.V., Dwivedy, K.K.,
Banerjee, D.C., Mohanty, R and Satyasaradhi, Y.R., 1999. Anatomy ofsurface rupture zones of two stable continental region earthquakes, 1967
Koyna and 1993 Latur India. Geophys.Res.Lett., 26, 1985-1988.
Joshi, V.P. and Bisht, R.S. 1994. “India and the Indus Civilization”
National Museum Institute, New Delhi, 1994, 22-31.
Kayal, J.R., Reena De, Das, B and Chowdhury, S.N., 1996. Aftershockmonitoring and focal mechanism studies; Killari earthquake. GSI SPL
PUB 37, 165-185.
McCalpin, J. 1996. Paleoseismology, Academic Press, 588pp.

62

New Technologies for Urban Safety of Mega Cities in Asia
153

ICUS Report 6
Oldham, R.D., 1899. Report of the great earthquake of 12th June, 1897,
Mem. Geol. Surv. India, reprinted: 1981, Geol. Surv. India, Calcutta,
379p.
Oldham, R.D., 1926. The Cutch (Kachh) earthquake of 16th June 1819 witha revision of the great earthquake of 12th June 1897. Geological Surveyof India Memoir, 71-147.
Rajendran, C.P., Rajendran, K., and John, B., 1996. The 1993 Killari (Latur),
Central India, and Earthquake: An Example of Fault Reactivation in the
Precambrian Crust. Geology, 24, 651-654.
Rajendran, K., and Rajendran, C.P., 1999a. Seismogenesis in the Stable
Continental Interiors: An appraisal based on two examples from India.
Tectonophysics, 305, 355-370.
Rajendran, C.P., and Rajendran, K., 1999b. Geological investigations at
Killari and Ter, Central India and their Implications for Paleoseismicity
in the Shield Region. Tectonophysics, 308, 67-81.
Rajendran, C.P. and Rajendran, K., 2001. Characteristics of deformationand past seismicity associated with the 1819 Kutch earthquake,Northwest India. Bull. Seism. Soc. Am., 91, 3, 407-426.
Rajendran, K., Rajendran, C.P., Thakkar, M., Gartia, R.K., 2002. Sand
blows from the 2001 Bhuj earthquake reveal clues on past seismicity,
Current Science, 83, 5, 603-610.
Rajendran, C.P. and Rajendran, K., 2002. Historical constraints on previous
seismic activity and morphologic changes near the source zone of the1819 Rann of Kutch earthquake: Further light on the penultimate event.
Seism. Res. Lett., 73, 470-479.
Rajendran, C.P., Rajendran, K., Vora, K.H. and Gaur, A.S., 2003. The odds
of a seismic source near Dwarka, NW Gujarat: An evaluation based on
proxies. Current Science, 84, 5, 695-699.
Rajendran, C.P., Rajendran, K. Duarah, B.P, Baruah, S. and Earnest, A.,
2004. Interpreting the style of faulting and paleoseismicity associatedwith the 1897 Shillong, northeast India, earthquake: Implications forregional tectonism, Tectonics, 23, doi 10.1029/2003TC00165.
Rao, B.R and Rao, S., 1984. Historical seismicity of peninsular India. Bull.
Seism .Soc. Am., 74, 2519-2533.
Seeber, L., and Armbruster, J. 1981. Great detachment earthquakes along
the Himalayan arc and long-term forecasting, in: Earthquake Prediction:
An International Review, Maurice Ewing Ser. Vol. 4, edited by D.W.
Simpson and P.G. Richards, AGU, Washington, D.C., pp. 259-277, 1981.
Seeber, L., Ekstron, G., Jain, S.K., Murty, C.V.R., Chandak, N and
Armbruster, J.G., 1996. The 1993 Killari earthquake in central India: A
new fault in Mesozoic basalt flows? Journal of Geophysical Research,
101, 8543-8560.
Sukhija, B.S., Rao, M.N. Reddy, D.V. Nagabhushanam, P., Hussain, S.,
Chadha, R.K and Gupta, H.K., 1999a. Paleoliquefaction evidence andperiodicity of large prehistoric earthquakes in Shillong Plateau, India.
Earth and Planetary Sci. Lett., 167, 269-282.
Sukhija, B.S., Rao, M.N. Reddy, D.V. Nagabhushanam, P., Hussain, S.,
Chadha, R.K and Gupta, H.K., 1999b. Timing and return period ofmajor paleoseismic events in the Shillong Plateau, India, Tectonophysics,
308, 1999b.

Understanding the Seismic Sources in India: Strategies for Seismic Hazard Reduction
154

63

October 2004, Agra, India

Wesnousky, S.G., Seeber, L., Rockwell, T.K., Takkur, V.C., Briggs, R.,
Kumar, S and Ragona, D., 2001. Eight days in Bhuj: Field Bearing on
surface rupture and genesis of the 26 January earthquake in India, Seism.
Res. Lett., 72, 514-524.

64

New Technologies for Urban Safety of Mega Cities in Asia
155

CAPACITY BUILDING IN INDIA TOWARDS
EARTHQUAKE RISK REDUCTION - ROLE
OF IIT KANPUR IN PAST TWO DECADESSUDHIR K. JAIN AND C.V.R.MURTHY
Indian Institute of Technology Kanpur, India
skjain@iitk.ac.in and cvrm@iitk.ac.inIndia faces moderate to severe seismic hazard over 60% of its land area.
The lessons learnt from earthquakes that occurred in the country in the lasttwo decades indicate that the country is far from being prepared to faceearthquakes with no fatalities and minimal economic setback. IIT Kanpur
recognized this national need about decades ago, and undertook small
initiatives that set out small goals that address different facets of thisnational challenge of marching towards earthquake preparedness. The major
work undertaken at this institute is focused on developing seismic designand construction in the country. The various initiatives include:(a)

Teaching the subject of earthquake engineering as part of theundergraduate and post-graduate programs, and to practicing
professionals and teachers of other colleges in India as part of thecontinuing education programs;(b) Conducting research on specific aspects of earthquake resistant designand construction through research conducted by students and researchsponsored by various governmental agencies in the country;(c)Undertaking a comprehensive review of the seismic codes in India,
developing provisions for seismic design and construction afresh thateventually lead to new Indian standards, and proposing modifications toexisting provisions;(d) Setting in place a national clearing-house at IIT Kanpur for collection
and dissemination of information at the national level on earthquake
resistant design and construction;(e)Working with the Ministry of Human Resource Development of theGovernment of India in planning and executing the first phase of amajor initiative of developing a teaching resource in the subject ofearthquake resistant design and construction in engineering andarchitecture colleges in India; and(f)Initiating a set of small projects and human resource nuclei that are
expected to eventually create a professional environment of strong andvibrant community of professionals with a background in earthquake
resistant design and construction.

1
156

October 2004, Agra, India
Details of these macro and micro initiatives undertaken at this Instituteare given in the documents listed below:______,

Earthquake

Engineering

at

IIT

Kanpur,www.nicee.org/EQ_Engg/eq_engg.htm.
Jain, S.K., and Murty, C.V.R., “Some Capacity Building
Initiatives in India on Earthquake Risk Reduction,” Proceedingsof the World Congress on Natural Disaster Mitigation, New
Delhi, 19-22 February 2004, Vol.1, pp 217-222.

Jain, S.K., and Agrawal, P., “Earthquake Engineering Capacity
Building in Educational Sector in India,” CD ROM Paper No.
3245,

13th World Conference on Earthquake Engineering,

Vancouver, Canada, 1-6 August 2004.
______, Programme Implementation Plan, National Programme
on Earthquake Engineering Education, Ministry of Human
Resrouce Development, Government of India, New Delhi,
www.nicee.org/npeee.

______, National Programme on Earthquake Engineering
Education (NPEEE), Ministry of Human Resource Development,
Government of India, New Delhi, www.nicee.org/npeee______, National Information Center of Earthquake Engineering(NICEE), Indian Institute of Technology Kanpur, www.nicee.org.

Murty, C.V.R., “IITK-BMTPC Earthquake Tips - Learning
Seismic

DesignandConstruction,”

www.nicee.org/EQTips/IITK_BMTPC.htm.

2

New Technologies for Urban Safety of Mega Cities in Asia
157

CASUALTY OCCURRENCE MECHANISM
INDUCED BY TRAIN ACCIDENTDURING AN EARTHQUAKEJUNJI KIYONO AND KATSUMI NAGAI
Graduate School of Engineering, Kyoto University, Japankiyono@quake.kuciv.kyoto-u.ac.jp
ABSTRACT
Damage to railway facilities is reported in the past earthquakes.
Especially in the 1995 Hyogo-ken Nanbu Earthquake, totally thirty-two
railway bridges were collapsed, and eight of which occurred at the San'yo
super express line. Fortunately the train accidents caused by the damage tobridges have not been reported so far. Although the large earthquake thatstrongly affects the train behavior hardly occurs, the effect of the accident tothe society is unpredictable once such large earthquake will occur. In thisstudy, we modeled a train and passengers in the train as distinct elements
and simulated their behavior by DEM. The impact force acted on the humanbody is computed and compared with the results from the experiments doneby the automobile engineering field. It is found that the velocity of 80 km/h
is a transition speed for both behaviors of trains and damage to passengers.
1.0 INTRODUCTION
Many damages to railway facilities are reported in the recent historicalearthquakes. Train accidents occur in nine past earthquakes in Japan. In the
1995 Hyogo-ken Nanbu Earthquake, seventeen trains were derailed, but
fortunately nobody died by the accident. The trains of the Southern Pacific
Railway in U.S. were also derailed during the 1994 Northridge earthquake.
Damage to railway bridges was occurred in the 1964 Niigata Earthquake,the 1978 Miyagi-ken Oki Earthquake and the 1989 Loma Preate Earthquake.
Thirty-two railway bridges including eight bridges of the San’yo super
expressway were collapsed in the 1995 Hyogo-ken Nanbu Earthquake.
Many train accidents induced by earthquakes have been reported, however,
the terrible accident such that the trains crashed into a collapsed part of thebridges has never happened so far.
Although a large earthquake just beneath the urban area has seldom
occurred, we have to anticipate and prepare for such a severe train accident.
In this study, the case that the trains crash into a collapsed part of a
destroyed overhead bridge is considered. Behaviors of the trains andpassengers in them are simulated by use of the Distinct Element Method(DEM). We calculate the force that acts on the human body, and discuss thehuman casualty of the earthquake-induced train accident according to thedamage criteria to the body for the car accident.

167
158

October 2004, Agra, India

Figure1: Train-collapsed bridge model(a) 2D section of the train (interior space, seats and passengers)(b) 3D model of seats and passengers
Figure 2: Analytical model of the inside of the train
2.0 METHOD
A train and a human body are modeled as a three dimensional rigid
element. The trains and the overhead bridge with a collapsed part are shownin Figure 1. The human bodies are expressed by spherical elements andarranged as shown in Figure 2 (a) and (b). The trains are numbered from aright side as No.1-No.16, and the human elements also from No.1 to No.20
for each row (A-E).
2.1 Equation of motion
The DEM, a numerical analysis method that computes the position ofeach element by solving the equations of motion step by step, was used.

168

New Technologies for Urban Safety of Mega Cities in Asia
159

ICUS Report 6

(a) normal direction(b) tangential direction
Figure 3: Contact model (virtual spring and dashpot)
All the elements are assumed to be rigid. Virtual springs and dashpots
in the normal and tangential directions are generated when an element
comes in contact with other elements (Figure 3). The contact force acts
through these generated virtual springs and dashpots. By solving theequation of motion for each element step by step, the behavior of all theelements can be traced. The forces acting on an element are the external
force (fx, fy, fz) and the total sum of the contact forces between elements (Fx,Fy, Fz). Accelerations of an element in a 3D case are calculated by:x  ( f x   Fx ) / m

F )/mz  ( f   F ) / my  ( f y 
z

(1)

y

(2)

z

(3)

in which m is the element’s mass and t the time increment in the analysis.
Assuming that acceleration is constant for the short period, t, the velocity
and displacement of each element can be calculated by the following
difference scheme. Total structural behavior therefore can be traced.
 xt   xt  t   xt  t 

 
  
 y t    y t  t    yt  t t z   z  z  t   t  t   t  t (4)

 xt   xt  t   xt  t 

 
  
 yt    yt  t    y t  t t z  z t   t  t   zt  t 

(5)Casualty Occurrence Mechanism Induced by Train Accident During an Earthquake

169

160

October 2004, Agra, India
(a) sphere-sphere(b) sphere-plane(c) sphere-cylinder(d) cylinder-cylinder

Figure 4: Contact patterns of the element
Rotation is obtained from Euler's equations of motion. Equations for the -,-, and -directions are
I
I
I

d 
dt
d 
dt
d 
dt

 ( I   I  )     ( r  F )iii

 ( I   I  )     ( r  F )iii

 ( I   I )    ( r  F )
i

i

i

(6)
(7)
(8)

in which and  are the inertia axes of the coordinates, and Ii and i(i= ) respectively are the moments of inertia and rotational velocities
around the center of gravity in the inertial frame of reference.
2.2 Contact judgment
When elements come into contact, the spring and dashpot are
generated in the calculation. Judgment of contact for the 3D analysis isbased on the use of spherical and cylindrical elements, but the process is thesame 2D circular elements. The contact models for the 3D analysis, shownin Figure 4; upper left is a case in which the spherical elements are incontact, upper right the spherical element and plane, bottom left the170

New Technologies for Urban Safety of Mega Cities in Asia
161

ICUS Report 6spherical element and cylindrical element, and bottom right cylindricalelements. Judgment of contact is made by considering the collocation
between the two elements concerned.
In order to make the judgment simple, the train was modeled by theuse of 1/8-sphere and 1/4-cylinder for its corner and edge. The rail wasmodeled 1/2-cylinder.
2.3 Contact force
Increments of the restoring and damping forces in the normal andtangential directions, (en, es, dn, ds), for the interval t are expressedby the increments of relative displacement in the normal and tangential
directions, n and s;
e n  K n ne s  K s sd n  C n n / td s  C s s / t

(9)
(10)
(11)
(12)

in which Kn and Ks, and Cn and Cs, respectively are the spring constants anddamping coefficients in the normal and tangential directions. The restoringand damping forces in each direction, ([en]t, [es]t, [dn]t, [ds]t) at the arbitrary
time t are obtained from the preceding equations;[e n ] t  [e n ] t  t  e n
[ e s ]t  [ e s ]t   t   e s[d n ]t  d n
[d s ]t  d s

(13)
(14)
(15)
(16)

When the restoring force exceeds the friction limit, the tangential force isgoverned by dynamic friction. The total contact forces in both directions are[ Fn ]t  [en ]t  [d n ]t
[ Fs ]t  [e s ]t  [d s ]t

(18)
(19)

The forces, Fx, Fy and Fz, in Eqs. (1), (2) and (3) are obtained by combining
the above forces in the target direction.
3.0 PARAMETERS USED IN THE ANALYSIS
3.1 Element parameters of train and human body
The various parameters of the train are determined according to the
700-type bullet train [Table 1, and Figure 5 (a), (b)]. The parameters of thehuman body are given by using the experimental results (Kiyono et al.,Casualty Occurrence Mechanism Induced by Train Accident During an Earthquake
162

171

October 2004, Agra, India1998) as shown in Table 2. The speed of the train is defined when the train
has reached to 5m behind the collapsed place. The contact parameters of the
train and the human elements are used according to the previous study(Kiyono et al., 2003).
Table 1: Element parameters for trainm (ton)I (ton･m2)I (ton･m2)I (ton･m2)
l(m) [Car No.1 & No.16]l(m) [Car No.2 to No.15]
b(m)
h(m)
lG(m) [Car No.1]
lG(m) [Car No.2 to No.15]lG (m) [Car No.16]bG(m)hG (m) [Car No.1 & No.16]hG (m) [Car No.2 to No.15]
lt (m)
hb(m)

44.25
42.28
2304.782346.81
11.53
12.50
3.38
3.65
11.53
12.50
15.82
1.69
0.636
0.650
9.20
1.30

Table 2: Element parameters for human body
r(m)
0.219

m (kg)
64.00

I (kg/m2)
1.228(a) lead and tail car(b) intermediate car

Figure 5: Parameter of the train
3.2 Chest-G and HIC
Damage to human body is assessed by the combination of the
maximum impact acceleration (Chest-G) and Head Injury Criteria (HIC)
frequently used in the field of car engineering. The value of HIC is
calculated as follows;

172

New Technologies for Urban Safety of Mega Cities in Asia
163

ICUS Report 6



Figure 6: Classification of damage levels(a) 80km/h(b) 150km/h

Figure 7: Behavior of the train with (a) 80km/h and (b) 150km/h in speed

1
HIC (t )  [T {  a( )d }2.5 ] max
T(20)

In which t is an arbitrary time and T the duration time of the impact thatsatisfies T<36 (msec). The assessment of the damage based on the Chest-G
and HIC is shown in Figure 6. We compared the simulation results of the
car crash to the wall with those of the experiment in order to check thevalidity of the analysis. Both were in good agreement (Kiyono et al., 2003).
4.0 SIMULATION OF TRAIN ACCIDENTThe number of the trains is 16, the passengers in No.1 and No.16 car
are 65 and intermediate car 100 persons. The span length and height of theCasualty Occurrence Mechanism Induced by Train Accident During an Earthquake
164

173

October 2004, Agra, India(a) 0.0sec(b) 1.6sec(c) 3.2sec(d) 4.8sec

Figure 8: Behaviors of passengers in the car No.1 (80km/h)
collapsed overhead bridge are 30m and 10m, respectively. The reclining
angle of the seat is 10 degree. The input ground motions used are the threecomponents recorded at the Kobe Marin Observatory in the 1995 Hyogoken Nanbu earthquake. The input ground motion is assumed to propagate
with an apparent velocity of 3km/sec in order to express three dimensional
behavior of the train. The constraint of y-direction movement is released
when the transversal acceleration exceeds 570gal or the uplift height fromthe rail exceeds 30mm, then the train derails.
Figure 7 (a) and (b) show the behaviors of the trains of which speeds
are 80 and 150km/h, respectively. In case of 80km/h, the first train hits tothe side wall directly, and the second car is lifted up. The deformation to they-direction becomes large with increase in speed, however, each car almost
collides head-on. In case that the speed exceeds 150km/h, the first two trains
jump upward in order to release the energy. The behaviors of passengers in
the car No.1 with 80km/h speed are shown in Figure 8 (a), (b), (c) and (d).
As the train tilt and fall into the collapsed part of the bridge, the passengers
in the train show the complex behaviors.
5.0 DAMAGE ASSESSMENT TO HUMAN BODY
The damage to human bodies is estimated by using the indexes of
Chest-G and HIC. Analytical conditions of the train are same as the previous
section. The speeds are varied such 6 cases as 50, 60, 70, 80, 90, and100km/h. Damage levels for all passengers in the trains are calculated. The
damage rate for each speed is shown in Figure 9. When the speed is lessthan 60-70km/h, more than 90% of passengers are ranked as triple-A. Whenthe speed becomes 100km/h, more than 60% of passengers are ranked as D.
The damage level of human body changes drastically around 70-80km/h.

174

New Technologies for Urban Safety of Mega Cities in Asia
165

ICUS Report 6



Figure 9: Damage rate for various speeds

Figure 10: Average damage level for each car
Figure 10 shows the average damage level for each car. The rate ofrank-AAA becomes large in the first car because its behavior is very
complicated such like falling, crashing, and jumping. The rate of rank-D
becomes smaller as the train is locating in the front position except Car No.1.
The main reason that the force to the x-direction is decreased as thedisplacement to the y-direction becomes large for the front cars.
6.0 CONCLUSION
In this study, we simulated the earthquake-induced train accident
when the overhead bridge collapsed by the strong ground motion. When the
train speed exceeds 150km/h, the trains show very complicated behaviors
such like falling, crashing, and jumping. The damage to passengers in the
train was calculated according to the index of Chest-G and HIC. The
damage level to human body also changes around the transition speed of 7080km/h.

Casualty Occurrence Mechanism Induced by Train Accident During an Earthquake
166

175

October 2004, Agra, IndiaACKNOWLEDGEMENT
This research is supported by the Takahashi Industrial Economics andResearch Foundation. The authors deeply acknowledge for this support.
REFERENCES
Kiyono, J., F. Miura and H. Yagi, 1998. Simulation o Evacuation Behavior
in a Disaster by Distinct Element Method. Proc. of the Japan Society of
Civil Engineers, No.591/I-43, 379-390 (in Japanese with English
abstract).
Kiyono, J. and K. Nagai, 2003. Earthquake-induced Train Accident and Its
Casualty Occurrence Mechanism. Journal of Social Safety Science, 5, 110 (in Japanese with English abstract).
Nagase, K., K. Kondo and T. Nomura, 1997). Train Damaged by the Quake
in Kobe. Proc. of the Japan Society of Mechanical Engineering, 63(606),
300–307 (in Japanese).
National Organization for Automative Safety and Victim’s Aid, 2000. New
Car Assessment, Japan (in Japanese).



176

New Technologies for Urban Safety of Mega Cities in Asia
167

DAMAGES TO MASONRY BUILDINGS IN
DIEN BIEN PHU EARTHQUAKEPHAN QUANG MINH
Hanoi University of Civil Engineering, Vietnam
pqminh1001@yahoo.com


ABSTRACTOn February 19th , 2001, a 5.3 on Richter scale an earthquake struck
Dien Bien Phu Town (North West Vietnam), where most of buildings are
masonry. This paper presents an overview of damage to masonry buildingsin the affected area and problems related to their strengthening
1.0 INTRODUCTION
Vietnam is a country situated in seismically active region. Within thelast 10 years a number of earthquakes have occurred in North West Vietnam,with the earthquakes in 1981 and 2001 measuring 6.6 and 5.3 respectively
on Richter scale. The last event occurred at 22:53 local time on February
19th 2001. The epicenter was located 15 km from Dien Bien Phu Town, thefocal depth was 12 km. Numerous aftershocks were recorded withmagnitude of 4,2 to 4,9 on Richter scale. The earthquake resulted ineconomic consequences to the one of poorest regions of Vietnam.
For a long time, in Vietnam design norm, the earthquake load was not
required for the design of buildings, except these of high importance. Up tonow, Vietnam still has no official code for the seismic resistant design ofbuildings. The study of Dien Bien Phu earthquake damage plays a very
important role in the compiling of Vietnamese norm for seismic design. In
this article, the damages to masonry buildings and their strengthening are
discussed.
2.0 DAMAGES OF MASONRY BUILDINGS
Dien Bien Phu Town is located in the North West Vietnam with
227,000 citizens, a number of whom are from ethnic minorities. The
majority of 1-storey and 2-storey buildings constructed before 1994 wereunreinforced masonry with low strength of materials (burnt brick, lime
mortar). Most of the bearing walls were 220 mm thick. Due to the local
design preferences and climate conditions, the houses had high first storeys(about 4.2m) with large openings. The R/C slab of these constructions ismade 70-80 mm thick. After 1994, reinforced concrete frames with infill
masonry are used for buildings with 2 to 4 storeys in the town. In thesuburbs, however houses with brick bearing walls and R/C slabs are widelyused. None of the constructed buildings are following any seismic provision.
The earthquake in 2001 caused:1168

October 2004, Agra, India

Up to 7700 damaged houses, 70% were 2-3 storey buildings, outof which 1257 buildings were heavy damaged. Most of thedamaged buildings were unreinforced masonry. The bearing walls
were subjected to the out-of-plane deformation, the width of cracks
was to 4cm. The cracks of bearing walls were almost diagonal andoften located between two openings or near the corners ofbuildings (Fig 1).

Figure 1: Damage of bearing wall






The reinforced concrete frames were not affected, only observed
cracks of infill masonry related to bond slip or openings.
2-storey building of Dien Bien Phu secondary school was heavy
damaged. The structure of this building was brick bearing wallswith R/C slabs. Interesting to note that another school building
with the same structure, located down the hill and 30m far fromfirst building, was experienced very little damage.
1 irrigation construction was damaged due to ground failure.
There is one high structure in the area, the TV steel tower with
40m high, located on the hilltop. The tower was not affected,
although some bracing elements were bent.

According to the investigation of the masonry buildings in affectedareas, some main reasons for damage and failure were identified as given in
Table 1.
Table 1: Causes of failures in masonry structures(a) Defect of construction(b) Lack of confining ties in
unreinforced masonry(c) Long walls (compared to their
thickness)(d) Previously occurring cracks inwalls (due to settlement, etc.)2(e) Openings close to corners.
(f) High first storey(g) Soft first story(h) Low strength of materials(i) Bending of slabs(j) Poor connection between R/Cframes and infill masonry

New Technologies for Urban Safety of Mega Cities in Asia
169

ICUS Report 6


3.0 RESTORATION & STRENGTHENING OF MASONRY BUILDINGS
After the main earthquake, most damaged buildings were temporality
supported. A decision to repair, restore or strengthen these needed to betaken urgently and depended on the level of damage. For example, it was
decided to destroy and rebuilt buildings with very heavy damage, strengthen(with addition RC elements) those with substantial to heavy damage, andrestore buildings with upto moderate damage. Also, the technique of
restoration and strengthening took into consideration the short time and low
cost of construction, locally available material, and the capability of thesemi-skilled labors, etc.
3.1 Restoration of buildings
For bearing walls with large cracks, the procedure adopted was – (a)Removal of portions of cracked masonry walls and rebuilding them in richmortar, followed by (b) providing steel clamps, perpendicularly to cracks orreinforcement key to be inserted into the wall (Fig. 2) and replastering. In
order to reduce the time involved in construction, the keys were precast.
3.2 Strengthening of buildings
3.2.1 Grouting
Grouting injection has gained popularity in recent years as an effective
method for repairing or strengthening of masonry walls and requires
equipment for mixing and pumping. In Dien Bien Phu, non-shrinking
Portland cement grout mixture was used for strengthening of bearing wallsof the school and some residential buildings with crack’s width to 10mm.
The technique of grouting injection requires equipment and skill labors, so
its application is limited.
3.2.2 Inserting new RCC elements
For unreinforced masonry, R/C framing columns and collar beams
were provided. Columns were located in corners and junctions of walls. In
some cases, in order to improve the bond of the new R/C structure with thewall, additional steel bars were inserted for connected existing slabs withcolumns (Fig. 3).

Figure 2: Inserting precast RC key into
damaged wall
Damages to Masonry Buildings in Dien Bien Phu Earthquake
170

Figure 3: Inserting new R/C column

3October 2004, Agra, India

Figure 4: Strengthening of constructing
building with new R/C columns


4.0 CONCLUSION
After Dien Bien Phu earthquake in 2001, many newly constructed tallbuildings in Vietnam were designed against the horizontal earthquake
loading. Vietnam has not enough experience of earthquake damage and sostudy of foreign codes is very important in order to compile the Vietnamesecode of practice for seismic resistant design of buildings.
5.0 REFERENCES
Arya, A.S, Teddy Boen, Yuji Ishiyama, Martemianov, A.I., Meli, R.,
Charles Scawthorn, Vargas Julio, N., Ye Yaoxian, 1986. Guide-lines forearthquake resistant non-engineering construction
Hisaka Okada, 2001. Report on Japanese activities on performance-based
building structural design. The 6th APEC workshop on International
Alignment of Codes and standards in building construction. Hanoi,
March 2001.
Ninh N.L., Minh P.Q., 2002. Seismic design of buildings. Research Project,
Hanoi (in Vietnamese).
Paulay, T., Priestley, M.J.N., 1992. Seismic design of reinforced concreteand masonry buidings. John Wiley & Sonc, Inc.
Phong N.T., Minh P.Q., Thanh, V.L., 2001. Report on Lai chau Earthquake.
National workshop on "Buildings and constructions in seismically active
regions". Hanoi, April, 2001 (in Vietnamese).
RMS Event Report. 2003 San Simeon, California Earthquake.

4

New Technologies for Urban Safety of Mega Cities in Asia
171

SEISMIC VULNERABILITY ANALYSIS OF
BUILDINGS IN JABALPUR URBAN AREASHAILESH KR AGRAWAL AND AJAY CHOURASIA
Central Building Research Institute, Roorkee, India
bdlcbri@datainfosys.net
ABSTRACT
Experiences of earthquakes in last few decades have caused deep
concern as regards to seismic vulnerability and resulting nature of disaster.
The rapid industrial growth, population explosion and consequent
escalation of urbanization with accelerated pressure on housing industry,
render the entire domain of built environment vulnerable to earthquakes.
The interest of social and economic stability requires recognition ofearthquake risk, commitment & preparedness to encounter the hazard andtheir mitigation, through seismic vulnerability studies of urban centers. The
paper presents an approach for assessment of seismic vulnerability ofbuildings whereat seismic vulnerability of existing building stock has been
estimated quantitatively and qualitatively. The quantitative approachcovers demand-capacity computation, while qualitative procedure estimates
structural scores based on national & international state-of-the-art
procedures viz. Rapid Screening Procedure (RSP). The study presented
here is aimed to carry out seismic vulnerability of existing building stock toprognosticate the damage pattern of existing building stocks of Jabalpur
urban area in the event of future earthquake. The results are mapped for
different types of buildings viz. Adobe/Mud houses (Type-A), Masonrybuildings (Type-B) and reinforced concrete (Type-C) buildings and collatedusing Arch Info and GIS, compatible for planning of pre-disaster mitigation
measures.
The study concludes that most of the buildings in Jabalpur are
constructed based on socio-economic consideration rather than engineering
approach.
The construction practices, materials used and quality of
construction for Type-A buildings are varied in nature from one region toother region in the area lacking seismic resistant measures and are likely tofail in the event of an earthquake. The majority of building stock (70%)
composed of Type-B buildings out of which 16% buildings are safe, while
84% buildings are likely to suffer damages in form of excessive cracking,falling of walls, falling hazard of non-structural components and then
combinations. Similarly, RC constructions (15%), are mainly designed forvertical loads and no special provisions are being accounted as far as
earthquake resistance is concerned. In case of an earthquake, around 45%
buildings are safe whereas rest of Type-C buildings are likely to suffer
damages in the form of excessive cracking, diagonal cracking, falling
hazard and its combination.

5172

October 2004, Agra, India

1.0 INTRODUCTION
The semi-urban and urban parts of India are being visited byearthquakes recurrently. The resulting disaster caused by Uttarkashi (1991);
Latur (1993); Jabalpur (1997); Chamoli (1999); & Bhuj (2001) are
testimony to the vulnerability of our existing built enviornemtn. In thiscontext, not only the well known seismic belts of Himalayan-Nagalushai
region, Indo-Gangetic Plain, Western India, Kachchh and Kathiawar regionsin geologically unstable parts of the country, where most devastating
earthquakes of the world have been witnessed, but also other seismic zones
where events such as Latur (M6.3, 1993) and Jabalpur (M6.0, 1997)
earthquakes have wreaked devastation in recent past are of equal concern.
The damages in huge proportions to the engineered and non-engineered
structures during Bhuj earthquake have shown that not only the source
ground characteristics but also the vulnerability of the built environment
render the domain susceptible to earthquake hazards.
A deterministic approach to hazard and risk analysis (DHRA) has beenresorted and based on the experiences of preliminary studies on
microzonation, a conceptual model for SHRM has been evolved (Mishra,
P.S. et al, 2001; Agrawal et al, 2003) . It envisages four level microzonation
viz. (a) base or 1st level geoscientific microzonation, (b) microzonation with
geotechnical inputs on ground characterization, (c) microzonation
improvised with parameters on site effect and ground response, and (d)seismic risk microzonation with engineering, seismological inputs onvulnerability of engineered and non-engineered structures and anthropic
parameters of population living in dwelling susceptible to damage and otherexposure factors. The seismic vulnerability is a measure of the seismic
strength or capacity of a structure, hence it is found to be the main
component of seismic risk assessment and microzonation thereof is being
presented here.
2.0 SEISMIC VULNERABILITY OF BUILDINGS FOR JABALPUR
The seismic vulnerability study comprise mainly review of theexisting buildings of Jabalpur in the light of guidelines for earthquake
resistant construction in India, behavior of buildings during 1997 earthquake,construction practices being adopted in Jabalpur urban area (pre & post
earthquake), building typologies, designing of questionnaire for survey ofbuildings, zoning of the Jabalpur urban area, selection of representativebuilding samples, detailed survey of selected buildings, and creation of
database. Subsequently, seismic vulnerability of existing building stock
estimated quantitatively and qualitatively. The quantitative approach covers
demand-capacity computation, while qualitative procedure estimates
structural scores using Rapid Screening Procedures (RSP). The results are
mapped using ArcInfo and GIS which are later synergized with seismic
hazard microzonation to deliver seismic risk.

6

New Technologies for Urban Safety of Mega Cities in Asia
173

ICUS Report 6

2.1 Existing building scenario in Jabalpur urban area
India has a very complex socio-cultural environment and its built
environment encompasses the widest possible range from non-engineered
dwellings built with traditional skills to the most modern buildings, andJabalpur is no exception. The Jabalpur urban area under study is spread over
290 sq. km., comprising of around 6.2 lakhs dwellings of different typology(Table-1).
Table 1: Distribution of Houses by Predominant Materials of Roof/Wall*

Type-A

Type-B

Type-C

Type-X

Wall & Roof Combination

Census Houses
No. of Houses
%

Urban
Rural
Total
Urban
Rural
Total
Urban
Rural
Total
Urban
Rural
Total

74,825
2,85,650
3,60,475
1,82,655
47,115
2,29,770
9,405
1,775
11,1809,480
6,125
15,605
6,17,030

20.75
79.25
58.42
79.50
20.50
37.24
84.10
15.90
1.81
60.75
39.25
2.53

Grand Total
Building Category
Type-A: Buildings in field-stone, rural structures, unburnt brick house, clayhouses
Type-B: Ordinary brick building, buildings of the large block andprefabricated type, half-timbered structures, building in natural hewnstoneType-C: Reinforced building, well built wooden structures
Type-X: Other types not covered in A, B, C.
*
Source: Vulnerability Atlas of India (1999)
The majority of houses in villages under Jabalpur urban area are of (a)mud (reinforced with straw), having 60 – 75 cm thick walls, (b) thick stone
strips in mud/lime mortar, having wall thickness of 35 to 60 cm, (c) unburnt
clay bricks in mud/lime mortar having wall thickness of 35 - 50 cm (Type-A
Structures). The roofs are made of thatch of bamboo or other plants,
covered with earthen tiles supported on wooden purloins. The roof andcantilever projections all around the houses are supported on wooden
ballies/wooden columns/mud pedestals.
There is no interlocking /connection between the wall and roof, making the same more vulnerable
during earthquake. The supporting columns are connected with wooden

Seismic Vulnerability Analysis of Buildings in Jabalpur Urban Area
174

7

October 2004, Agra, India

rafters by wedge kind of triangular wooden element. The various elementsof trusses made-up of wooden ballies are interconnected using nails and allgable ends found without any connection/gable band.
The existing building stock (around 70%) in Jabalpur city is comprisedof brick masonry in cement mortar (1:8)/ lime / surkhi / mud mortar, with
230 mm to 750 mm thick load bearing walls (Type-B Structures). Thesedwellings are mainly 2 to 3 storey with 3.00 to 3.3 m storey height. The
construction practices and material used for these houses seem to vary withtime. It has been found that no earthquake resistant measures have been
adopted in buildings constructed before 1997 earthquake. Implementationof BIS codal provisions regarding earthquake resistant design &construction (IS: 4326-1993), were found to be absent almost in all thesample buildings surveyed, rendering the large percentage of structure
seismically vulnerable. However, the post 1997 construction make use offour RCC columns of size 230 x 230 mm in corners, and RCC beams at
lintel and floor level. In some of the newer construction lintel and plinth
bands were found to be present.

Photo 1: Existing building typologies in Jabalpur urban area
The RC framed buildings are not much prevalent (around 15%) in
Jabalpur urban area. General construction of RC framed buildings are of
nominal concrete of M15 grade (1:2:4) ranging from 3 to 4 story with story
height of 3.00 to 3.30 m (Type-C Structures). Among majority of RC framebuilding, around 90% buildings are soft story, with uniform cross section ofcolumns although, having RCC slab of 120-140 mm thickness and 200-250
mm thick brick masonry in CM (1:6) as infill. These RC buildings aremainly designed for gravity loads without giving much attention to ductility
provisions as enumerated in BIS: 13920-1993.

8

New Technologies for Urban Safety of Mega Cities in Asia
175

ICUS Report 6

2.2 Experiences of Jabalpur earthquake of 1997 (M6)
Jabalpur lies close to a mature zone of seismic source with recurrent
seismic activity. On 22nd May 1997, the area was rocked by an earthquakeof 6.0 magnitude (focal depth ~ 35 km) with epicenter at latitude 23.08oN
and longitude 80.06oE. The Jabalpur urban domain lied in the near field of
the seismic event and was in meizoseismal zone having undergone wide
spread damage of MSK intensity VIII. The post-earthquake reconnaissancesurvey during 1997 in the area carried out by difference agencies viz. GSI(Mishra, P.S. et al, 2000), CBRI (Agrawal, S.K. et al, 2002), IIT Kanpur(Jain, S.K. et al, 2001), IIT Roorkee (Rai, D.C. et al, 1997), revealed that theperformance of existing building stock was poor. The obvious reason has
been that earthquake resistant measures prescribed in Indian codes were notmade mandatory.
2.3 Past attempts for assessment of vulnerability
The first attempt to create Vulnerability Atlas of India (MP) – 1997
(Arya, 1997) details out housing vulnerability tables wherein damage risk
levels for earthquakes are defined based on the intensity scale such as Very
High, High, Moderate, Low, and Very Low, and categorization of houses
has been carried out based on distribution of houses by predominantmaterials of roof and wall, according to 1991 Census. The statewise
Vulnerability Atlas, describing districtwise damage risk due to earthquake,wind and flood has been prepared Accordingly, the earthquake damage
risk associated for Jabalpur urban area varies from very low, low, &medium to Type-C, Type-B, & Type-A houses respectively. However, May
1997 Jabalpur earthquake caused severe damages leading to collapse ofType-A and Type-B houses, in particular, based on various damage survey
reports. There has not been any other reported literature on seismic
vulnerability of existing building stocks of Jabalpur urban area, which is oneof the important modules for any SHRM study.
3.0 SEISMIC EVALUATION: METHODOLOGY
Indian buildings built over past two decades are seismically deficientbecause of lack of awareness regarding seismic behavior of structure,
constant upgradation of knowledge as regards earthquake resistant design &construction. Also seismic design is not practiced in most of the buildings
being built. It calls for seismic evaluation of existing building stocks in an
area.
Evaluation is a complex process, which has to consider not only thedesign of building but also the deterioration of the material and damage
caused to the building, if any. The difficulties faced in the seismic
evaluation of a building are manifold. There is no reliable
information/database available for existing building stock, construction
practices, in-situ strength of material and components of the building. The
seismic evaluation mainly relies on set of general evaluation statements.

Seismic Vulnerability Analysis of Buildings in Jabalpur Urban Area
176

9

October 2004, Agra, India

The unavailability of a reliable estimate of earthquake parameters, to which
the building is expected to be subjected during, its residual life poses
another challenge. Probabilistic approach to evolve needful parameters,
would call for elaborate studies. Hence, for preliminary appraisal, theground motion parameters available in the present code (IS:1893-2002)
have been estimated at the macro level. As regards the effect of local soil
conditions, which are known to greatly modify the earthquake groundmotion, experiences of ground accentuation and data generated throughcollateral studies on site response have been considered. Also, in view ofabove constraints, the present study is limited to seismic evaluation ofrepresentative buildings of different typology viz. Type-A (Mud/RR
Masonry, Adobe), Type-B (Brick Masonry Buildings), and Type-C (RCC
Buildings), and projects a generalized pattern of building response to future
seismic ground motion in different wards/zones of Jabalpur urban area.
The seismic evaluation leading to seismic vulnerability of existingbuilding stock at Jabalpur has been estimated quantitatively andqualitatively.
The quantitative approach, covers demand-capacity
computation (ATC-40, 1996), while qualitative procedure estimates
structural scores based on national & international state-of-the-art
procedures viz. Rapid Screening Procedure (ATC-21, 1988, ATC-211,1988). The general procedures for seismic evaluation of existingbuildings adopted in the present study are: site visit & data collection;
selection & review of evaluation statements; follow-up fieldwork; andanalysis of buildings by quantitative and qualitative approach.
3.1 Designing of questionnaire
Designing of questionnaire comprising of set of evaluation statements
is the first and foremost step for any seismic vulnerability analysis. The
questionnaire would help the surveyor to determine any weak links in the
structure that could precipitate structural or component failure. Although
for macroseismic/post-earthquake damage investigations several
questionnaires (Gunthal, 1993) are devised, however, for pre-earthquake
seismic evaluation of existing building stocks there is no standard
questionnaire at international & national levels. Hence, a need was felt todesign exhaustive questionnaire to uncover the flaws and weaknesses ofbuildings/built environment. In the backdrop of available practices being
adopted all over the globe, a comprehensive questionnaire has been
designed. The questionnaire involves the use of sets of evaluation
statements which cover structural configuration & specification, conditionof structure & ambience, scenario of distress in non-structural components,
seismic vulnerability parameters, damage during previous earthquake andrepairs carried out thereof, and assessment of scientist/surveyor.
Thequestions are in form of fill-in-the-blanks and evaluation statements
highlighting building characteristics which are essential to avoid failuresduring earthquake.

10

New Technologies for Urban Safety of Mega Cities in Asia
177

ICUS Report 6

3.2 Site visit and building survey
3.2.1 Administrative units of Jabalpur urban area
In order to evaluate seismic vulnerability of huge number of building
stocks in Jabalpur urban area, it is practically impossible to survey each andevery house; hence it is imperative to divide Jabalpur urban area into
number of small zones based upon structural/population density. The
Jabalpur urban area is divided into 60 numbers of municipal wards as
delineated by Jabalpur Nagar Nigam (Municipal Corporation of Jabalpur).
These 60 wards are taken as zone in the present analysis. In addition,
Jabalpur Cantonment Area and surrounding villages have been considered
as a separate zone. Detailed reconnaissance survey of existing buildings
stocks of each ward has been conducted. Based upon the observations, 3-4
representative building samples of different building typologies are selected
for detailed investigation from each ward.
3.2.2 Selection of building samples
During the detailed survey, buildings of each type (i.e. Type-A, TypeB, and Type-C) have been identified, with the assumption that selectedbuilding represents construction practices being prevalent in that particular
ward/zone. This was done with the mutual consensus amongst the teammembers and Corporator of the ward. Wherever the construction practices
varied drastically in a ward, more number of samples were identified so as
to cover the each type of construction in a ward. The sample survey wasdone with the aim that the seismic vulnerability analysis to be carried out on
those sample buildings which would represent seismic vulnerability of eachtype of building in that zone.
3.2.3 Detailed survey of selected buildings
Apart from filling-up of questionnaire for the selected buildings,
surveyor has to inspect the health of structure critically to assess its seismic
resistance. In the process, surveyor has to face several difficulties. The
foremost problem is of uncovering the structure. In many buildings the
structure is concealed by architectural finishes, and the surveyor will have to
get into attics, crawl spaces. Non-availability of plans, and design
calculations is yet another problem, and is particularly frustrating withrespect to reinforced concrete work. Assessing material quality andassociated allowable stresses is also difficult preposition, and one has to rely
on local available reports/information or otherwise one has to go for
destructive testing, which is seldom possible. Destructive and nondestructive testing of reinforced concrete and masonry elements arenecessary to determine strength and quality of construction. The reboundhammer is used to assess the compressive strength of concrete structuralmembers, wherever access is provided in reinforced concrete structure. If
reinforcement details are available, a limited amount of exposure of criticalreinforcement is needed to verify conformity to the plans/structural details.

Seismic Vulnerability Analysis of Buildings in Jabalpur Urban Area
178

11

October 2004, Agra, India

If the plans are not available, the quality of reinforcement is assessed byexposing reinforcement to a limited extent.
The sample survey was carried out for about 474 buildings spread over
62 zones of Jabalpur urban area including 22 surrounding villages, out of
which 33% are of Type A, 52% are of Type B and 15% are of Type C.
3.3 Seismic vulnerability analysis
The seismic vulnerability analysis of all types of buildings have been
carried out by two different approaches. For qualitative assessment ofbuildings, Rapid Screening Procedure is used to assess vulnerability of all
types of structures, while for quantitative approach, DCR computation has
been used for Type B & C buildings and later it is related with the possible
failure modes.
3.4 Quantitative seismic vulnerability for masonry buildings
Since earthquake is a random process, all the load bearing walls in a
structure are to be evaluated for their shear resistance. The demand placedby an earthquake i.e. lateral forces at various levels, as per IS:1893-2002,
along with gravity load calculations were carried out for sample buildings,
and later check in terms of Demand –Capacity ratio (DCR) for shear
resistance, combined stress, overturning, and stability of non-structural
failures for long and short walls. The capacity of wall is defined as its
allowable stress depending upon mortar type in accordance with the relevant
codal provisions. The DCR greater than unity, indicates that the building isseismically vulnerable in respective criterion, whereas DCR less than one
implies the building to be safe under earthquake loads. As indicated earlier,earthquake demands for better shear resistance and hence the DCR in shear
should be less than one, otherwise the building will have diagonal (X)cracking. The DCR greater than one for combined stresses means that thebuilding is not even designed for gravity loads and would lead to collapse
on seismic shaking. The failures in overturning corroborates falling of walls.
The check for non-structural element implies the falling hazard of parapet
wall. The above analogy has been used to estimate seismic vulnerability interms of various failure modes i.e. collapse, excessive cracking, falling ofwalls including parapet walls.
3.5 Quantitative seismic vulnerability for RC buildings
In order to critically evaluate the RC framed buildings, selectedbuilding sample were modeled using sophisticated structural analysis
software under combination of earthquakes & other wards for computing
the member end forces in each structural member. Apart from the dead &live loads, is analyzed for design basis earthquake (DBE) loads, theearthquake loads which can reasonably be expected to occur at least once
during the lifetime of the structure. Accordingly, dead load, live load andtheir combination as suggested in IS-1893-2002 have been considered for

12

New Technologies for Urban Safety of Mega Cities in Asia
179

ICUS Report 6

analysis. The analysis directly computes member end forces and then eachmember is designed for worst load combination. The design module ofanalysis engine gives the longitudinal and transverse reinforcement for eachmember. This reinforcement corresponds to the demand of a member due toearthquake forces, whereas the actual reinforcement provided in a particularmember would correspond to capacity. In order to calculate the DCRs, thecalculated reinforcement of structural members has been compared with
provided reinforcement. The DCRs for longitudinal and transverse
reinforcement reflects DCRs for flexure and shear of member. The DCRs
calculated for flexure and shear gives the idea about inherent ductility andstrength of member to ensure safety & serviceability during severe shocks.
The DCR greater than one for flexure indicates that the longitudinal
reinforcement in columns & beams are inadequate leading to failure. The
possibility of failure of such buildings is excessive cracking leading tocollapse. Whereas DCR greater than one in shear indicates that the lateralties provided are not sufficient leading to brittle failures i.e. catastrophic
failure. In this case, there is possibility of diagonal cracking in structuralelements. The check for non-structural element implies the falling hazard ofparapet wall. Based upon above analogy, DCRs for flexure, shear andnon-structural members leading to estimate seismic vulnerability in terms offailure modes i.e. excessive cracking, diagonal cracking and falling hazard
respectively, for all the representative RC buildings under consideration
have been computed.
3.6 Qualitative seismic evaluation for buildings
The Rapid Screening Procedure (RSP) is aimed to identify potentiallyhazardous buildings in the study area, without going into detailed analysis.
RSP utilizes a methodology based on visual inspection of a building andnoting the structural configuration.
The methodology begins withidentifying the primary structural lateral load resisting system and materialsof the building. The method generates a Structural Score ‘S’, which
consists of a series of ‘scores’ and modifiers based on building attributes
that can be seen during detailed survey. The Structural Score ‘S’ is related
to probability of the building sustaining life-threatening damage in the eventof occurrence of a severe earthquake in the region. A low S score suggeststhat the building is vulnerable and needs detailed analysis, whereas a high‘S’ score indicates that the building is probably adequate. RSP helps indeveloping a list of potentially hazardous buildings without a high cost ofdetailed analysis of each building. In the present study, this method has
been used for qualitative assessment of seismic vulnerability of existingbuildings in Jabalpur urban area.
3.7 Prognostic damage scenario of Jabalpur urban area
The prognostic damage scenario of a ward reflects the structural andnon-structural damages induced in the existing building stocks.
Thedamage scenario of a ward given here is based on representative building
surveyed for different building typologies.

Seismic Vulnerability Analysis of Buildings in Jabalpur Urban Area
180

13

October 2004, Agra, India

Based on the survey & analysis of data, the seismic vulnerability of
Jabalpur urban area obtained through qualitative approach. It is found that
Type-A, Type-B & Type-C buildings are 100%, 87% and 33% vulnerable
respectively.
In order to present the prognostic damage scenario for Jabalpur urban
area using quantitative approach, the failures modes of different type ofbuildings are collated, and indicates that all the Type-A houses are 100%
vulnerable since they are built from socio-economic consideration rather
than engineering. For Type-B buildings, the postulated failure modes havebeen categorized as excessive cracking (EC); falling of walls (FW); falling
hazard of non-structural members (FH); and combination thereof Excessive cracking + falling of wall (EC+FW); excessive cracking + falling
hazard (EC+FH); falling of wall + falling hazard (FW + FH); excessive
cracking + falling of wall + falling hazard (EC + FW + FH); and safebuildings (which do not have any failure). At the first instance, wardwise
seismic vulnerability has been derived, and later the ensemble is projected topresent prognostic damage scenario for Jabalpur urban area. The prognostic
damage scenario for Jabalpur urban area for Type-B structures obtained as“Excessive Cracking (EC) works out to 15%; Falling of Walls (FW) – 0%;
Falling Hazard of non-structural members (FH) – 29%; and combination
thereof - Excessive Cracking + Falling of Wall (EC+FW) – 2%; Excessive
Cracking + Falling Hazard (EC+FH) – 36%; Falling of Wall + Falling
Hazard (FW + FH) – 1%; Excessive Cracking + Falling of Wall + Falling
Hazard (EC + FW + FH) – 1%; and Safe buildings – 16% (Fig. 1).

15%

16%

1%

0%

1%

29%
36%
2%
EC

FW

FH

EC+FW

EC+FH

FW+FH

EC+FW+FH

SAFE

Figure 1: Prognostic damage scenario of Type-B buildings in Jabalpur
Similarly, the various failures modes for assessing seismic
vulnerability of Type-C buildings are identified as excessive cracking (EC),diagonal cracking (DC); falling hazard of non-structural members (FH); andcombination thereof and safe buildings. The prognostic damage scenario
for Type-C buildings in Jabalpur urban area obtained as “Excessive
Cracking (EC) – 0%; Diagonal Cracking (DC) – 0%; Falling Hazard (FH) –14

New Technologies for Urban Safety of Mega Cities in Asia
181

ICUS Report 634%; Excessive & Diagonal Cracking (EC+DC) – 9%; Diagonal Cracking+ Falling Hazard (DC+FH) – 7%; Excessive Cracking + Falling Hazard(EC+FH) – 7%; Excessive Cracking + Diagonal Cracking + Falling
Hazard (EC + DC + FH) – 32%; and safe buildings – 11%. The overallprognostic damage scenario of Jabalpur urban area for this kind of buildings
is presented in Fig. 2. The falling hazards are essentially non-structural
failures and therefore these buildings may also be deemed to be safe afterminor modification to non-structural elements making around 45% safe RC
structure.
0%
11%

0%
34%

32%

9%

7%

EC

DC

FH

EC+DC

7%

DC+FH

EC+FH

EC+DC+FH

SAFE

Figure 2: Prognostic damage scenario of Type-C buildings in Jabalpur
Figure 3 presents Prognostic Seismic Vulnerability Map of Masonry
Buildings in Jabalpur. The vulnerability map can be effectively used toproject the risk associated with existing building stock in Jabalpur Urban
area. Further, these maps may act as guidance for future planning, risk
reduction and disaster mitigation and management.
4.0 CONCLUSIONS
Based on qualitative and quantitative analysis of the data collectedduring the survey and its analysis & interpretation, the following
conclusions for predicting seismic damage scenario for Jabalpur are drawn:

 The buildings in field-stone, rural structures, unburnt brick house,clay houses (classified as Type-A), comprises of 15% of totalbuilding stock in Jabalpur urban area. The construction practices,materials used and quality of construction for Type-A buildings
are varied in nature from one region to another region in the area.
All the buildings lack seismic resistant measures and are likely tofail in the event of an earthquake.

Seismic Vulnerability Analysis of Buildings in Jabalpur Urban Area
182

15

October 2004, Agra, India

Figure 3: Prognostic seismic vulnerability of masonry buildings in
Jabalpur urban area

 The majority of building stock (70%) in Jabalpur area composedof Type-B buildings which include ordinary brick buildings,
buildings of the large block, half-timbered structures, buildings innatural hewn stone. As regards to seismic damage scenario,
around 16% buildings are safe, while 84% buildings are likely tosuffer damages in form of excessive cracking, falling of walls,
falling hazard of non-structural component and combination
thereof.
 The engineered RC construction in the region typically consists of
RC Moment Resisting Frames (Type-C) with infilled brickmasonry walls, which constitutes about 15% of total building
stock. The buildings are found to be designed for vertical loads
only with no special provisions for earthquake resistance. In caseof an earthquake around 45% buildings are safe whereas rest ofType-C buildings are likely to suffer damages in the form ofexcessive cracking, diagonal cracking, falling hazard and its
combination.
 The study presents the seismic damage scenario of Jabalpur urban
area taking into account all prevalent construction practices,material of construction, quality/workmanship of construction,
types of buildings, ambience, geological / geotechnical parameters
based on ground realities. However, the limitation of study has
been that it is based on a limited sample size of 474 representativebuilding from different microzones of Jabalpur urban area.

16

New Technologies for Urban Safety of Mega Cities in Asia
183

ICUS Report 6

 The present study on vulnerability when integrated for damage
scenario analysis on incidence of earthquake with collateralgeoscientific studies corroborates the finding of revalidated
intensity map of Jabalpur Earthquake 1997.
These risk microzonation studies demands special attention withreference to heritage/monumental buildings, lifelines like rail/road, watersupply, electric supply, sewage, communication, dams, hospitals & schools,
vulnerable industries, which is missing in the present study. Also there is aneed to identify safe zones/domains/structures and secure routes to work as
a relief centers and relief dispersion on incidence of future disaster.
ACKNOWLEDGEMENTS
The authors gratefully acknowledge the financial support from the
Department of Science & Technology, Government of India for financial
support for the above study. Authors are thankful to Dr P.S. Mishra,
Director, Geological Survey of India, Nagpur for valuable suggestion &guidance offered during the study. The authors also thank Shri V.K. Mathur,
Director, Central Building Research Institute, Roorkee, for granting
permission to publish the paper.
REFERENCES
Arya, A. S. 1997. Madhya Pradesh: Vulnerability Atlas of India. BMTPC,
Ministry of Urban Development, New Delhi, India.
Agrawal, Shailesh Kr., and Chourasia, Ajay 2004. Estimation of Seismic
Vulnerability of Buildings in Delhi. World Congress on Natural Disaster
Mitigation organized by Institution of Engineers (I), Kolkata, Feb. 2004.
Agrawal, Shailesh Kr., Chourasia, Ajay, and Parashar, J. 2003. Seismic
Vulnerability of Buildings in Jabalpur Urban Area. Vol V, DST Report,
Central Building Research Institute, Roorkee.
Agrawal, S.K., Chourasia, Ajay, and Parashar, J. 2002. Seismic Evaluation& Retrofitting of Existing Buildings. 12th Symposium on Earthquake
Engineering, Indian Institute of Technology, Roorkee.
Agrawal, S.K., Chourasia, Ajay, Parashar, J and Dutta, J.
2002.
Experimental Investigation on Earthquake Resistance and Retrofitting
Measures of Masonry House. Advances in Concrete & Construction
Technology, Publication –3, Interline Publishing, Bangalore.
ATC-21, 1988. Rapid Visual Screening of Buildings for Potential Seismic
Hazards: A Handbook. Applied Technology Council, Redwood city, CA,USA.
ATC-21-1(1988), “Rapid Visual Screening of Buildings for Potential
Seismic Hazards: Supporting Documentation”, Applied Technology
Council, Redwood city, CA, USA.
ATC-40, 1996. Seismic Evaluation and Retrofit of Concrete Buildings. Vol.
1, Applied Technology Council, Redwood city, CA, USA.

Seismic Vulnerability Analysis of Buildings in Jabalpur Urban Area
184

17

October 2004, Agra, India

Grunthal G., 1993. European Macroseismic Scale 1992 (up-dated MSKscale. European Seismological Commission, Luxembourg, 1993.
IS:1893-2002, 2002. Criteria for Earthquake Resistant Design of Structure.
Bureau of Indian Standards, New Delhi.
IS:4326-1993, 1993. Code of Practice for Earthquake Resistant andConstruction of Buildings. Bureau of Indian Standards, New Delhi.
IS:13920-1993, 1993. Ductility Detailing of Reinforced Concrete Structures
Subjected to Seismic Forces-Code of Practice. Bureau of IndianStandards, New Delhi.
Jain, S. K., Murty, C. V. R., Dayal, U., Arlekar, J. N., and Chaubey, S. K.,
2001. A Field Report on Structural and Geotechnical Damages
Sustained During the 26th January, 2001 M7.9 Bhuj Earthquake in
Western India. NICEE Report.
Mathur, V.K., Agrawal, Shailesh Kr., and Chourasia, Ajay 2004.
Microzonation Studies as Impacted by Recent Earthquakes in India.
World Congress on Natural Disaster Mitigation organized by Institutionof Engineers (I), Kolkata, Feb. 2004.
Mathur, V.K., Agrawal, S.K., and Chourasia, Ajay 2003. Demand-Capacity
Approach for Seismic Rehabilitation of RC Residential Buildings. 9thInternational Conference on Civil & Structural Engineering Computing(CIVIL-COMP 2003), Heriot Watt University,, Edinburgh, UK.
Mishra, P.S. et al 2000. Jabalpur Earthquake – 22 May 1997- A
Geoscientific Study. GSI Special Publication No. 51, Geological Surveyof India, Calcutta.
Mishra, P.S. et al 2001. Base Level Seismic Hazard Microzonation of
Jabalpur Urban Area, MP. National Symposium on Role of Integrated
Development & Related Issues, GSI Special Publication No. 65(iii),
Calcutta, pp 249-258.
Rai, D.C., Narayan, J.P., Pankaj, Kumar, A. 1997. Jabalpur Earthquake of
May 22, 1997 – Reconnaissance Report. Department of Earthquake
Engineering, University of Roorkee, Roorkee.
Vulnerability Atlas of India 1999. Building Materials & Technology
Promotion Council, New Delhi.

18

New Technologies for Urban Safety of Mega Cities in Asia
185

AN INNOVATIVE SEISMIC
STRENGTHENING METHOD FOR
UNREINFORCED MASONRYSTRUCTURES USING PP-BAND MESHESPAOLA MAYORCA AND KIMIRO MEGURO
IIS, The University of Tokyo, Japanpaola@iis.u-tokyo.ac.jp
ABSTRACT
Rapid urbanization and city grow are common features worldwide.
This phenomenon is transforming city skylines due to the remarkableincrease of high-rise buildings and infrastructure. In spite of this, numerous
existing structures are and will be used in the future. Many of thesebuildings are made of seismic vulnerable materials, such as unreinforced
masonry, posing a great danger to urban development in seismic prone
regions. The potential risk that these structures represent to human lives inlarge metropolis is aggravated by the high concentration of people.
Therefore, increasing their seismic resistance is imperative.
In order to effectively promote seismic retrofitting, one of the key
issues is to enable inexpensive technical solutions which could be executedwithout highly skilled labor. In this context, this paper discusses aninnovative strengthening technique for unreinforced masonry structuresusing polypropylene band (PP-band) meshes embedded in a mortar overlay.
These bands, which are commonly used for packing, are resistant,
inexpensive, durable and worldwide available. The PP-band meshes areeasily attached on both sides of the wall and connected with wires passed
through holes drilled in the wall. In this way, the structure disintegration
under seismic loads is prevented.
In order to verify the suitability of the proposed method, a series ofmasonry walls, with and without retrofit, were tested under in-plane loads.
Although the retrofitted wall peak strength was almost the same as that of
the bare wall, its post-peak strength became much larger and sustained forlateral drifts over 2%.
1.0 INTRODUCTION
Masonry is a construction material widely used around the world due
to its low cost and construction easiness. More than 30% of the world’s
population lives in a house of unbaked earth, which is one type of
unreinforced masonry (Houben and Guillaud, 1989). During the last century,
human casualties during earthquakes were mainly caused by structural
damage, being the failure of unreinforced masonry structures responsible ofmore than 60% of them (Coburn and Spence, 1992). The vulnerability ofmasonry structures under seismic loads has being recognized long ago and19186

October 2004, Agra, Indiaefforts to provide guidelines for the construction of sound earthquake
resistant houses have being remarkable. In spite of this, every year
casualties due to collapsing masonry houses during earthquakes are reported.
Several types of retrofitting have been developed for unreinforced
masonry structures. A comprehensive review of them can be found in
Lizundia et al (1997). The existing retrofitting techniques can be categorized
in: 1) grout and epoxy injections, 2) surface coatings, 3) reinforced or posttensioned cores, and 4) addition of structural elements. There is no doubtthat these methods are useful for strengthening masonry structures.
Depending on the purpose of the retrofitting works, one method is more
appealing than the other.
For strengthening unreinforced masonry houses in developing
countries, a suitable retrofitting technique should guarantee not only its
efficiency in terms of improvement of the seismic resistant characteristics ofthe structure (strength, ductility and energy dissipation). It should also be
considered that: 1) the used material is economical and locally available and2) the required labor skill is minimum. In this context, a new retrofitting
method for unreinforced masonry structures is proposed.
2.0 RETROFITTING METHOD PROPOSAL
Considering the above-mentioned conditions, a novel retrofitting
method consisting of polypropylene bands (PP-bands) arranged in a meshfashion and embedded in a cement mortar overlay is proposed. These bands
are worldwide used for packing. They are cheap, resistant, and easy tohandle. The details of the retrofitting technique are discussed elsewhere(Mayorca and Meguro, 2003). Only a brief explanation of the installation
procedure is presented below.
At first, the meshes are prepared with the PP-bands. The pitch andinclination may vary according to the required earthquake resistance. Then,the masonry wall surfaces are cleaned and holes are drilled through the wallat a spacing of approximately 4 times the mesh pitch. After this, the PPband meshes are set on both wall sides and fixed at the borders. Galvanizedsteel wires are passed through the wall holes and used to fix the meshes.
Photo 1 shows the wall at this stage of the process. Finally, a mortar overlay
is placed on the wall surface.
3.0 EXPERIMENTAL PROGRAM
In order to assess the retrofitting by PP-band mesh, eight masonrywalls were constructed: four with and four without reinforcement. The wall
dimensions were 985×1072×100mm3 and consisted of 15 brick rows of
4.5 bricks each. Clay bricks were used. The mortar mix proportion involume was cement: sand=1:4.5 and the joint thickness was 10mm. The
bottom and top brick layers were embedded in steel channels. The walls
were cured with water spray for 14 days. At the end of the curing process,20

New Technologies for Urban Safety of Mega Cities in Asia
187

ICUS Report 6
the upper channel was installed. Figure 1 shows the test setup and specimen
dimensions.

Photo 1: Retrofitted wall before mortar overlay setting
Two meshes were prepared per retrofitted wall. The mesh pitch, equal
to 45mm, was chosen so that each brick would be crossed by at least threebands. Because the bricks were very strong, the connectors, 27 in total, wereplaced only at the mortar interface. This constrain defined the band
inclination, which was 50°. A cement mortar mix (cement: sand=1:3) wasused for the protection overlay of 8mm thickness.
At first, a vertical pre-compression load was applied by closing thebolts at the bottom end of six vertical rods. The force increment at the bars
was closely monitored. Then, the actuator was positioned and the forces atthe vertical rods were readjusted in case of unbalance. Finally, thehorizontal loading, which consisted of 5 steps, was applied with a hydraulicpump operated manually. In the first step, the wall was loaded until diagonal
cracking. The second step consisted on additionally pushing the wall 10mm
in the same direction. In the third step, the actuator displacement direction
was reversed and the specimen was loaded until the diagonal crack in the
opposite direction occurred. In the fourth step, the wall was loaded 10mm
more in the same direction. Finally, the wall was unloaded. Table 1 showsthe experiment program summary.
Due to the brick high strength, the resulting masonry was stronger
than the material typically available in developing countries. In order tointentionally reduce the wall strength and highlight the retrofitting effect,
holes were drilled through some of the walls. Two hole distributions wereconsidered, uniform and diagonal. Further details of the experimental
program may be found in Mayorca (2003).

An Innovative Seismic Strengthening Method for Unreinforced Masonry Structures using PP-Bands Meshes
18821

October 2004, Agra, India

Figure 1: Test setup and dimensions in mm
Table 1: Summary of experiment conditions
Case name
Bare wall
Bare wall w/ holes
Bare wall w/mortar
Reinforced wall
Reinforced wall w/holes
Bare wall w/mortar
Reinforced wall
Reinforced wall w/diagonal holes
VL=Vertical pre-compression load

VL
(kN)
9
9
9
9
9
30
30
30

PPbandOOOOMortar

Holes

O
O
O
O
O
O

None
Uniform
None
None
Uniform
None
None
Diagonal

4.0 RESULTS DISCUSSION
Photos 2 and 3 show typical crack patterns. Figures 2 and 3 show theforce-deformation curves obtained in the experiments grouped according to
the pre-compression load. The experimental observations are briefly
discussed below.
4.1 Crack pattern
As observed in Photos 2 and 3, the crack pattern did not change
considerably due to the reinforcement presence. In both cases, the flexuralstresses caused a crack at the lower most mortar layer at an early load stage.
This crack became gradually longer and wider as the horizontal loadincreased. In the case of the reinforced walls, the crack propagated slowly
and as a result, a wall strength drop was not observed in the forcedeformation curve. This effect was identified in the walls with VL=9kN.

22

New Technologies for Urban Safety of Mega Cities in Asia
189

ICUS Report 6The flexural crack caused the horizontal force, which was originallytransferred to the support by a shear-flexural mechanism, to be resisted
through a compression strut along the wall diagonal. As the bottom crack
stopped propagating, the specimen stresses continued to build up and were
eventually released through a diagonal crack.

Photo 2. Unreinforced wall crack pattern

Photo 3. Reinforced wall crack pattern
After the first diagonal crack, the wall strength was notoriously
reduced and the subsequent imposed deformation was related to the
movement of the upper half of the failed wall. Because of this, when theload was reversed it did not produce any additional flexural cracking. It was
mainly the upper wall displacement. After the initial shear crack closed, thestresses started to build up again and the second diagonal crack, along the

An Innovative Seismic Strengthening Method for Unreinforced Masonry Structures using PP-Bands Meshes
190

23

October 2004, Agra, Indiaother diagonal, appeared. The main difference between the unreinforced andreinforced walls was the crack propagation speed rather than the location.
4.2 Stiffness
The force-deformation curves presented in Figure 2 may suggest thatthe reinforced walls have a slightly higher stiffness than the unreinforced
ones. However, it must be noted that the deformations showed in the figurescorrespond to two effects, the wall deformation itself and the wall rotation.
The later is larger. Figure 4 shows the deformation along the wall diagonals,
which is a direct measurement of the wall shear deformation. Note that the
deformation of both reinforced and unreinforced walls is small and almost
the same. This shows the high stiffness of the masonry wall and suggeststhat the stiffness difference observed in the force deformation curves ismainly due to the reinforcement restrain to the wall rotation.

Figure 2: Force-deformation curve (VL=9kN)

Figure 3: Force-deformation curve (VL=30kN)

24

New Technologies for Urban Safety of Mega Cities in Asia
191

ICUS Report 6

Figure 4: Diagonal deformation (VL=30kN)
4.3 Peak strength
The PP-bands have a relatively low stiffness compared to the masonrywalls (Mayorca, 2003). Because of this, they did not contribute to increase
the wall peak strength. Although some differences are observed, these are
due to: 1) mortar overlay presence, 2) bonding between mortar overlay andmasonry wall, and 3) variability of masonry properties due to theworkmanship effect. The PP-band mesh contribution was only observed
after the wall cracked.
4.4 Post-peak strength
Figure 5 shows the force-deformation relation normalized to the peakstrength and corresponding deformation for the group of walls with
VL=9kN. It is observed that immediately after the peak, the normalized
strength dropped to 10 to 40% for the unreinforced walls. On the other hand,
the reinforced walls exhibited a 60% residual strength after the peak, which
was sustained for drifts over 2%. In the reverse direction, the reinforced
walls also exhibited a larger normalized strength.
4.5 Effect of connectors and mortar overlay
The reinforced wall with VL=30kN deserves special attention because
the wall strength after the diagonal crack dropped to almost 25% of the peakstrength. This was the only reinforced wall that exhibited such a sharp drop.
After the test, the specimen was examined and broken wire connectors were
found. Furthermore, a severe cracking of the mortar overlay due to drying
shrinkage was observed before the experiment. This may have caused a
reduction of the mortar support to the bands resulting in a larger demand to
the wire connections, which ultimately caused their failure. It is worth
noting that this was the first retrofitted wall constructed and eventually thesteel wires may have been damaged during the installation process.

An Innovative Seismic Strengthening Method for Unreinforced Masonry Structures using PP-Bands Meshes
192

25

October 2004, Agra, India

Figure 5: Normalized force-deformation relation (VL=9kN)
5.0 CONCLUSIONS
A new technique for strengthening masonry structures using PP-bands
is proposed. The results of shear wall tests showed the reinforcement effecton the masonry wall behavior. Although the reinforcement did not increase
the structure peak strength, it contributed to improve its performance after
the crack occurrence. The reinforced walls exhibited a larger post-peakstrength and were capable of better sustaining their strength even for drifts
over 2%. The importance of the connectors and the mortar overlay for the
retrofitted wall performance was recognized.
REFERENCES
Houben H. and Guillaud, H, 1989. Earth construction – A comprehensive
guide. ITDG Publishing, London.
Coburn A. and Spence R., 1992. Earthquake Protection. John Wiley & Sons
Ltd, West Sussex.
Lizundia, B., Holmes, W. T., Longstreth, M., Kren, A., Abrams, D. P., 1997.
Development of Procedures to Enhance the Performance ofRehabilitated URM Buildings. NIST GCR 97-724-1.
Mayorca, P. and Meguro, K., 2003. Efficiency of polypropylene bands forthe strengthening of masonry structures in developing countries. Proc.
of the 5th International Summer Symposium, JSCE, 125-128.
Mayorca, P., 2003. Strengthening of unreinforced masonry structures inearthquake-prone regions. PhD Dissertation, The University of Tokyo.

26

New Technologies for Urban Safety of Mega Cities in Asia
193

RESPONSE OF A BASE ISOLATEDMASONRY STRUCTURE
KRISHNAMOORTHY1, KIRAN KUMAR SHETTY2
AND RAVI KUMAR1
1
Manipal Institute of Technology, Manipal, India
2
N.M.A.M. Institute of Technology, Nitte, India
hodcivil2002@yahoo.com
ABSTRACT
A masonry building resting on laminated rubber bearing andsubjected to ground acceleration due to Koyna earthquake is analyzed using
three dimensional finite element method. The building and bearing ismodeled using eight noded isoparametric brick element with three degrees
of freedom at each node. The response of building isolated at base iscompared with the response of the building fixed at base. The response ofisolated building is found to be less in comparison to the corresponding
response without isolation system, implying that the isolation is effective in
reducing the response of the masonry structure. It is also found that thedisplacement at top and base of the isolated building are almost same at alltime intervals. This indicates that the building moves rigidly during
earthquake.
1.0 INTRODUCTION
Masonry buildings are increasingly used in all countries except
perhaps in the relatively more developed ones. Masonry walls are known tosuffer maximum damage during earthquakes. A number of base isolation
systems have been developed to isolate these buildings subjected toearthquake. Base isolation is an aseismic design approach in which thebuilding is protected from the severe earthquake forces by a mechanism,
which reduces the transmission of horizontal acceleration into the building.
One of the concepts to protect a building from the damaging effects of anearthquake is by introducing some type of support that isolates it from theshaking ground using specially designed bearing. These bearings are placed
between the structure and its foundation. These bearings can carry thegravity load of the superstructure in normal way and simultaneously provide
the horizontal flexibility necessary to shift its first mode natural frequency
away from predominant frequency of the design earthquake motion. This
results in the reduction of inertial forces and accelerations several times inthe structure. Base isolation is therefore recommended for life saving andlife threatening structures. Kelly (1986) carried out an extensive review on
the historical developments of the many mechanisms that have beendeveloped. Among the numerous designs of base isolators, the laminatedrubber bearings offer perhaps the simplest method of isolation and are
relatively easy to manufacture. In the present study a one-story masonrybuilding resting on laminated bearing and subjected to Koyna groundmotion is analyzed. The response obtained from the analysis of the building

47
194

October 2004, Agra, India

fixed at base is compared with the response obtained from the analysis of
the building isolated at base so as to study the effectiveness of base isolation.
2.0 ANALYSIS
The various assumptions made for analysis of the building mounted on
bearing are as follows:

The superstructure remains in the elastic range during theearthquake excitation.
The force – deformation behavior of the laminated rubber bearing
is considered to be linear

A three dimensional building frame resting on bearing and subjectedto earthquake ground acceleration is analyzed by finite element method ofanalysis. The three dimensional building and bearing is divided into numberof eight noded isoparametric brick element. The element is having threetransnational degrees of freedom at each node.. For each element, thestiffness matrix [k] and consistent mass matrix [m] are obtained. The mass
matrix and stiffness matrix of each element are added by direct stiffness
method to get the overall mass matrix [M] and overall stiffness matrix [K]for the entire structure. The overall damping matrix is obtained by using
Raleigh’s equation. [C] =  [M] +  [K] where  and  are the constants.
The overall dynamic equation of equilibrium for the entire structure can be
expressed in matrix notations as[M] { u }+[C ] { u }+[K] { u }={f (t)}(1)

where [M], [C] and [K] are the overall mass, damping, and stiffness
matrices. { u }, { u }, { u } are the acceleration, velocity and displacement
vectors and f(t) is the nodal load vector. The nodal displacement vector isequal to { u } = {u1, v1, , w1, u2, v2, w2, ….. un, vnwn} where n is thenumber of nodes.
The nodal load vector due to earthquake is obtained using the equationf (t) = - M I üg (t)(2)

where M is the overall mass matrix, I is the influence vector, üg(t) is theground acceleration. To determine the displacements and acceleration, theresulted equation of dynamic equilibrium is solved using Newmark’s
method. The displacement obtained at each node is assigned for eachelement. The stresses in each element are then obtained using these
displacements.

48

New Technologies for Urban Safety of Mega Cities in Asia
195

ICUS Report 6

3.0 RESULTS AND DISCUSSIONS

3m

wall

3m
bearing

3m

Figure 1: One-storey masonry structure resting on laminatedrubber bearing
A response of a masonry building subjected to Koyna earthquake
excitation is studied. A one-story masonry building mounted on laminatedrubber bearing considered for the analysis is shown in Figure1. The modulus
of elasticity and poisons ratio of wall is taken as 2 x 105 kN/m2 and 0.2
respectively. The stiffness of the bearing is adjusted in order to get theisolation period equal to 2.0 seconds. Damping is assumed to be 5% and
10% for superstructure and bearing respectively. The top floor displacement,base displacement, top floor acceleration, Von Mises stresses at bottom dueto this loading is computed at a time interval of 0.04 seconds for a total
period of 30.0 seconds. The variation of response with time is shown in
Figure 2 for fixed (Ts= 0.2 sec) as well as base isolated (Tb = 2.0 sec)
structure. It can be seen from the figure that the maximum acceleration andmaximum Von Mises stresses at bottom decreases due to isolation. However,
the maximum horizontal displacement increases due to isolation. Also thedisplacement at top and base of the isolated structure are almost same at alltime intervals. This indicates that the structure moves rigidly during
earthquake.

Response of a Base Isolated Masonry Structure49
196

October 2004, Agra, India

8
FixedIsolated2

Top floor acceleration (m/s )

6
4
2
0
0

5

10

15

20

25

30

20

25

30

20

25

30

-2
-4
-6
Time (sec)-830

Top floor displacement (Fixed)
Top floor displacement (Isolated)
Base displacement (Isolated)

Displacement (mm)

20
10
0
0

5

10

15

-10
-20
-30
Time (sec)-40

2

Von Moses stress at bottom (N/mm )

0.3
Fixed
Isolated
0.2

0.1

0
0

5

10

15
Time (sec)Figure 2: Response of masonry building for Koyna earthquake50

New Technologies for Urban Safety of Mega Cities in Asia
197

ICUS Report 6

4.0 CONCLUSIONS
The response of a masonry building resting on laminated rubber
bearing subjected to Koyna earthquake ground motion is studied. A onestorey masonry building resting on bearing is considered for study. The
effectiveness of base isolation is studied by comparing the response of baseisolated structure with the response of the fixed base structure. Based on theanalysis it can be concluded that the maximum acceleration and stresses inthe building decreases considerably. The maximum base displacement isalso within the limit. Hence the isolation using bearing can be usedeffectively used to reduce the effect of earthquake on masonry buildings.
ACKNOWLEDGEMENTS
This research was supported by grants from the University Grants
Commission, New Delhi. This support is gratefully acknowledged.
REFERENCES
Bhasker P, Jangid RS. 2001. Experimental study of Base isolated
Structures. Journal of Earthquake Technology ISET; 38, 1, 1-15.
Jangid RS, Dutta TK. 1992. Seismic behaviour of torsionally coupledbase isolated structure. European Earthquake Engineering. 3, 1-13.
Kelly JM.,1986. Seismic base isolation: review and bibliography. Soil
dynamics and Earthquake Engineering. 5, 202-216.
Paz M, 2001. Structural dynamics – Theory and Computation, 3rd Ed,
Van Nostrad Reinhold, New York.

Response of a Base Isolated Masonry Structure

51
198

URBAN BUILDING INVENTORY FROM VHR
REMOTE SENSING IMAGERYFOR EARTHQUAKE RISK ANALYSISIN BANGKOK
N.H.M. KAMRUJJAMAN SERKER1, PENNUNG WARNITCHAI2 AND
DUSHMANTA DUTTA3
1
Rajshahi University of Engineering and Technology, Bangladesh
2
SCE, Asian Institute of Technology, Thailand
3
ICUS, IIS, University of Tokyo, Japanddutta@ait.ac.th
ABSTRACT
Bangkok, the capital city of Thailand, is one of the mega cities in Asiaand a regional hub. The city has a very high economic growth and is going
through changes as new buildings and other structures are built. Bangkok is
considered free of seismic risk. Recent studies shows that the risk due todistant earthquakes needs to be evaluated because of high population
density and construction of concrete structures considering a little or noseismic loading. It is imperative to update the building and infrastructure
inventory to evaluate seismic risk and to establish proper management
plans for disaster reduction. Therefore, very high resolution (VHR) satellite
images are used to develop an inventory for building and infrastructures
located in the region considering their spectral, spatial and contextual
properties. Seismic risk due to scenario earthquake is evaluated using the
HAZUS methodology and inventory data obtained from image analysis incombination with the existing database. Scenario results are presented foran earthquake in the region.
1.0 INTRODUCTION
Bangkok (Figure 1), the capital city of Thailand, is one of the major
cities in Asia and is a regional hub. The city has a high economic growth
and a rapid urbanization and a massive scale of building construction havetaken place in Bangkok. Since Bangkok has long been considered by mostpeople as being free from seismic risk, most buildings and structures were
designed and constructed without any consideration on seismic loading.
However, recent studies indicate that there are several active faults locatedat about 120 to 300 km from Bangkok (Warnitchai, 2003). Warnitchai(2003) also found that these active faults exhibit very low levels ofseismicity, however, their expected rupture dimensions indicate that a large
earthquake of magnitude 7.5 could be generated. Instrumental records ofearthquakes in the Thailand-Burma-Indochina region over the past 90 years
also show that the active seismic sources, capable of generating large
magnitude earthquakes, are located at about 400 km to 100 km from
Bangkok. Moreover, Bangkok has the qualitatively similar surficial
geologic setting of Mexico City, and hence by analogy, Bangkok appears

71
199

October 2004, Agra, India


similar to be susceptible to the same soil amplification of ground motions(Warnitchai, et. al, 2000).
Disaster risk analysis is important not only to estimate the losses fromfuture event (or events) but also to make recommendations for prevention,
preparedness and response. Building inventories are essential for all types ofdisaster risk analysis models. With a slight difference in characterization ofbuilding types, all models require an estimate of number of buildings or
total square footage (Eguchi et al., 2000). Land use information is very
important for disaster risk analysis in urban areas. Traditional land
surveying methods, such as field surveys, aerial photography, etc. are costly
and time consuming. Padermkul (1999) developed an inventory
methodology for Bangkok using the multiple data sources. However thesesources contain old data and these files are not updated regularly. Also theavailable building inventories for Bangkok are old, paper-based and do notcontain the spatial information. In order to rapidly derive detailed land use
information in broad areas, it is necessary to use remote sensing techniques.
The launches of the IKONOS and Quickbird satellites in 1999 and2001, respectively, have improved the resolution power of the previously
most powerful commercially available satellite images by factors greaterthan 10. The Quickbird images provide 2.8 meter detail in multispectralmode (blue, green, red and near-infrared bands) and 0.6 meter inpanchromatic mode. This detail is comparable to aerial photography, but
satellite imagery has the advantage of being continuously updated without
having to cover great areas using an aeroplane with expensive equipment.
The availability of such images has given new possibilities to use satellite
images in high detail Geographic Information Systems, including cityplanning, real-estate inventory, natural risk management and any other kindof cartography.
A few studies, in the past years, were done to use satellite imagery todevelop building and other infrastructuresinventories for the selected areas.
Yamazaki et al. (2000) investigated the capability of developing building
inventory used for seismic risk analysis using satellite images fromLANDSAT, IRS, JERS-1, ADEOS and IKONOS. They used principal
component analysis and found this method as a possible solution to classify
urban structures. However, Sande et al. (2003) proposed a segmentation andclassification approach for IKONOS-2 imagery for land cover mapping toassist flood risk and flood damage assessment using object oriented image
analysis techniqueThis research was aimed to develop an up-to-date building inventory
using information obtained from remote sensing data analysis and existing
databases. The main objectives were as follows:

72

Analysis of very high-resolution satellite remote sensing
data for developing an inventory for buildings for an urban
area,
Use of the building inventory for earthquake risk analysis.

New Technologies for Urban Safety of Mega Cities in Asia
200

ICUS Report 6


2.0 STUDY AREA
The study site selected is a part of the Bangkok Metropolitan Area
(Figure 1). The area, measured about 52 km2, comprises of mainly
residential areas along with a few industrial sites. Most of the buildings are
single housing type. Only a few numbers of high-rise buildings was found in
the selected site. The common practice of building houses in the selectedarea is with concrete moment resisting frame with in filled non-reinforced
masonry walls. Reinforced concrete roofs, concrete tiled roofs, and metalroofing’s are very common in the selected study area. However, details
about the individual buildings were not found from any existing database.
The roads are found as cement concrete roads with foot over bridges atregular intervals. The roads are separated with wide road dividers and atroad intersections flyovers exist. There are trees along the roadsides and partof roads and building roofs are found shaded with tree.

Figure 1: The study area
3.0 METHODOLOGY
The overall approach adopted for development of an up-to-datebuilding inventory is shown in Figure 2. The existing building database was
supplemented with the outcomes of the image analysis of very highresolution remote sensing data for the study area. AGIS platform wasutilized to integrate the extracted information from image analysis andexisting information of the region.
QuickBird (panchromatic and multi-spectral) images were used in thisstudy, for development of urban building inventory. QuickBird image
specification is shown in Table 1. The primary objective of this study was toobtain information on buildings and other important structures, from very
high-resolution remote sensing data, located in the selected site.
There are two different approaches, visual interpretation and thematicclassification, of gathering information from satellite imagery. Pixel basedclassification and object oriented classification are two common methods ofthematic classification. In this study object oriented image analysis

Urban Building Inventory from VHR Remote Sensing Imagery for Earthquake Risk Analysis in Bangkok
201

73

October 2004, Agra, India

technique was applied to extract the desired information. The basic elementsof an object-oriented approach are image objects. Image objects arecontiguous regions in an image. Segmentation is the subdivision of animage into separated regions. Image segmentation was done using multiresolution image segmentation (eCognition, 2002).
Analysis of Very HighResolution Satellite Image

Existing Database, Informationfrom Local Region

GIS Analysis for
Urban Inventory

Modified Databaseof Urban Inventory

Figure 2: Overall inventory methodology
Table 1: QuickBird image properties.
Acquisition date
Spatial resolution

11/07/2002
2.80 m multi-spectral bands
0.60 m panchromatic

Spectral wavebands

0.45-0.52 m (Blue)
0.52-0.60m (Green)
0.63-0.69m (Red)0.76-0.90m (Near IR)

Map projection
View angle

Universal Transverse Mercator
Nadir

Swath width

16.5 km

Fuzzy classification is beside neural networks and probabilistic
approaches (Curlander and Kober, 1992), a very powerful soft classifier(Benz et.al., 2004). As an expert system (Tsatsoulis, 1993) for classification
it takes into account the followings (Benz et.al., 2004):

Uncertainty in sensor measurements
Parameter variations due to limited sensor calibration
Vague class descriptions
Class mixtures due to limited resolution

Four different levels were chosen to extract features of interest fromdifferent levels. Table 2 shows the segmentation parameters used as relativevalues and as a function of thematic land cover. As shown in the Table 2
and Figure 3, the spectral bands can either be included or excluded from the74

New Technologies for Urban Safety of Mega Cities in Asia
202

ICUS Report 6segmentation process. The scale parameter was the most important factor tocontrol the size of the objects. The classification was done on the image
objects using multi level classification approach based on fuzzy methods.
Fuzzy classification technique was applied with the help membershipfunction. Membership functions were developed based on the spectralreflectance characteristics and shape properties of the image objects.
Different features were separated using different membership functions.
One-dimensional membership functions were used in this study. To separate
different urban features, (e.g., concrete surfaces, nonconcrete surfaces,
green areas, Bareland, water bodies, etc) spectral information based onimage objects was used. Buildings were separated from roads based on theirshape properties. The classified image view is shown in Figure 4. Field
survey was carried out to obtain information about the features and to obtain‘ground truth’ data. Field survey data was used as the primary knowledge
base and was combined with the spectral information obtained from theimage objects to develop membership functions for different classes.
Table 2: Segmentation parameters used for analysis of QuickBird image.
Segmentation&
classification
level

Land
use
types

Level I

Homogeneity criterion

QuickBird bands used
Scale
Blue

Green

Red

NIR

All

Yes

Yes

Yes

Yes

Level II

Buildi
ngs &
Roads

No

Yes

Yes

Level III

Major
Roads

No

Yes

Level IV

Large
Water
bodiesNo

No

Shape settings

Color

Shape

Smoothness

Compactness

5

0.7

0.3

0.9

0.1

Yes

10

0.5

0.5

0.9

0.1

Yes

Yes

25

0.5

0.5

0.9

0.1

Yes

Yes

40

0.9

0.1

0.9

0.1

Table 3: Features extracted from QuickBird image analysis and digitization(% of total area)Class
Build upRoad
RC Building
NRC Building

Green
Bareland
Water
Shadow
OthersQuickBird
3.29
10.65
23.33
42.79
13.81
3.20
0.60
3.33

Digitized
4.24
10.20
20.10
57.61
3.85
3.30

Urban Building Inventory from VHR Remote Sensing Imagery for Earthquake Risk Analysis in Bangkok
203

75

October 2004, Agra, India
Image Objects

Spectral reflectance properties

Built up features

Non-Build up features

Spectral reflectance properties

Spectral reflectance properties

Concrete

Not Concrete

Shadow

Water
Bodies

Green

Bare
Land

Shape Properties

Roads



Buildings

Figure 3: Class hierarchy for analysis of QuickBird image
4.0 RESULT ANALYSESIn this study buildings and roads were given primary importance to be
extracted. Buildings were extracted from segmentations at levels 1 and 2.
Buildings were classified as reinforced and non-reinforced concretebuildings depending on their roofing materials and types. Small roads wereextracted from extracted from segmentation at level 2 where as large roads
were extracted from segmentation at level 3. Segmentation at level 4 wasused to classify the large objects, e.g. large water bodies, in the study area.
The classification results are summarized in Table 3. About 38% of the total
area was classified as built up area of which approximately. 35% of the total
area was classified as building area. From visual interpretation of thepanchromatic image of 60cm, approximately 36% of the total area wasclassified as built up area, which is about 95% of the area obtained fromimage analysis. It was possible to separate shadows from other features,
however, 33% shadow objects were classified as water.
4.1 Accuracy assessment
Verification of the classification results with the help of ground truth
data is a common technique in remote sensing data analysis. However, in
this study two different approaches, verification of results with ground truth
data and comparison of the results with the results obtained fromdigitization, were applied to verify the classification results. Table 4 shows
the verification of the classification results with ground truth data. In
general pixels are considered to verify the classification results. In this study,
image objects were considered to verify the classification system. An
overall accuracy of 85% was achieved with the classification scheme.
However some of the classes, e.g. RC buildings, green areas and bareland,
were classified with high level of accuracy up to 100%. Non RC buildings

76

New Technologies for Urban Safety of Mega Cities in Asia
204

ICUS Report 6

and roads were classified with accuracy of 70% and 80% respectively.
Digitized data of the study area was developed using manual classification
with the help of visual interpretation and photographs obtained from fieldsurvey. The areas of different features extracted from image analysis werecompared with the areas obtained by digitizing. The comparison of theresults obtained from two analyses is shown in Table 3. RC buildings area
extracted from image analysis was 95% of the area obtained by digitization.
Non RC buildings area was extracted as 116% of the digitized area. Shapesof buildings, roads and water bodies, extracted from image analysis, wereoverlaid on the shapes obtained from digitization. There was large deviation,in terms of regularity of shape, between two shapes.
Table 4: Error matrix for QuickBird image.
Building
Building

10

Road

2

Not Concrete

Road

Not
Concrete

Water

Shadow

Green

Bareland

Total
10

7

10
7

1

Water

8

Shadow

3

Green

2

8
6

9
10

Bareland

10

10
5

Total

5
62

Figure 4: Classified map with QuickBird image

Urban Building Inventory from VHR Remote Sensing Imagery for Earthquake Risk Analysis in Bangkok
205

77

October 2004, Agra, India


5.0 SEISMIC RISK ANALYSIS
The recent studies show that Bangkok can be experienced to a large
earthquake of magnitude 7.5. Also the site response analyses show that thesurficial deposits of Bangkok have the ability to amplify earthquake groundmotions about 3 to 4 times, and the amplified ground motions can be
describes as narrowband random motions with long predominant period of
about 1 second. Considering these factors an earthquake of magnitude 7.5
was selected to observe the building damage.
HAZUS99-SR2 was used for earthquake loss estimation in this study.
HAZUS has been developed by the Federal Emergency Management
Agency (FEMA) under the agreement with National Institute of Building
Sciences (NIBS). HAZUS is designed to produce loss estimate in different
levels (e.g. state, regional, and local government levels). HAZUS can beused in ARC View or ARC Info environment. An earthquake loss estimate
can be performed using HAZUS for any location using only themethodology and user supplied databases. The HAZUS methodology isoutlined in Figure 5.
5.1 Inventory development for risk analysis
The study was focused only on the damage of buildings anddistribution of damaged buildings. The classification of buildings was madeon the building structure types. Other classifications e.g. social function
classes, essentially needed for monetary and non-monetary loss estimation,
were not considered. The inventory was compiled using the extracted resultsfrom remotely sensed data and combining it with field survey data andexisting databases. From the field survey it was found that there exist mostly
single housing residential buildings. Most of the buildings are low-risebuilding. The number of high-rise buildings is not large. For theclassification of building the methodology provided by HAZUS was
followed. The total number of building was estimated from the QuickBird
panchromatic image as 7000. Approximately 79% of the buildings areassociated with residential housing. The land use statistics as obtained fromJICA report on “The Study on Urban Environmental Improvement Programin Bangkok Metropolitan Area” are shown in Tables 5 and 6.
5.2 Building damage estimation
Structural fragility curves were evaluated for spectral displacement
and spectral acceleration defined by the intersection of the capacity anddemand curve. The fragility curves for different types of structuralclassification that are used in this study were taken from HAZUS. Figure 6
shows the building damage distribution in the study region due to an
earthquake of magnitude 7.5. The damage states are used from the HAZUS.
The analysis shows that about 1.5% of the low-rise building got slightdamaged and 0.5% of the mid-rise building damaged slightly. None of thehigh-rise building received any damage due to the ground shaking caused by78

New Technologies for Urban Safety of Mega Cities in Asia
206

ICUS Report 6

the selected earthquake. The results of the building damage estimation are
given in Table 7.
Table5: Types of building according to function(% of total building constructed)
District
Residential
Bangkapi 37.41%
Bungkum 48.52%

Commercial Office30.56%
26.46%
30.42%
14.56%

Industrial
0.18%
1.37%

Others
5.39%
5.13%

Figure 5: Earthquake loss estimation using HAZUS (HAZUS99-SR2)
Table 6: Types of buildings according to height
Bangkapi
Type of Building
No. of stories

Low Rise
Mid RiseHigh Rise

1~3
4~7
8+

% of total Building

Total no of
Buildings

66.45
21.94
11.61

4,573
1,607
1,036

Table 7: Building damage data
Building
Type

No of
Buildings

No
DamageNo. of Building Damaged
Slight Moderate Extensive

Complete

C3L*
4,573
4,505
68
Nil
Nil
Nil
C3M*
1,607
1,599
8
Nil
Nil
Nil
C3H*
1,036
1,036 Nil
Nil
Nil
Nil
* C3L, C3M, and C3H represent low rise, midrise and high rise concrete
frame with unreinforced masonry infill wall building respectively as
described in HAZUS manual.

Urban Building Inventory from VHR Remote Sensing Imagery for Earthquake Risk Analysis in Bangkok
207

79

October 2004, Agra, India


6.0 CONCLUSIONSThis study was aimed to develop a GIS ready inventory for buildings
in selected districts of Bangkok city using remotely sensed data. Building
areas were classified with approximately 90% accuracy. The shapes of theroads and water bodies were found as regular shapes. However, the regularshapes of the buildings were not found from the image analysis. Finallyseismic risk due to an earthquake of magnitude 7.5 was evaluated using
HAZUS methodology.

Figure 6: Building damage distribution (low-rise buildings)

From this study, the following conclusions can be drawn:







80

QuickBird image can be a very good choice to develop an
inventory for urban features. City area consists of small and large
buildings and roads along with other structures. Small houses,
roads, water bodies and other features are clearly visible andidentifiable from QuickBird image.
In the selected study site, the roofing material consists of concrete,
metal sheets, wood etc. However, buildings were classified, basedon their roofing materials, as concrete and non-concrete buildings.
With the object-oriented classification scheme used in this study,
an overall accuracy of 85% was achieved in detailed classificationof urban landcover in the study area. The building area was
extracted with a high level of accuracy.
From this study, it was found that many urban features completely
or partly covered with trees and shadows. From analysis of
QuickBird image it was found that 0.6% of the total land area
covered by shadow. Using Remote sensing data, it is difficult to
extract accurately the features covered with trees or vegetal cover.

New Technologies for Urban Safety of Mega Cities in Asia
208

ICUS Report 6

Dynamic properties of buildings are needed to be evaluated toperform the risk analysis accurately. In this study all properties ofbuildings were directly used from HAZUS. So the results mayvery due to change in building properties.

REFERENCES

Benz, U.C., Hofmann, P., Willhauck, G., Lingenfelder, I., Heynen, M.,
2004. Multi-resolution, object-oriented fuzzy analysis of remote sensing
data for GIS-ready information. ISPRS Journal of Photogrammetry &Remote Sensing, vol. 58, pp. 239– 258
Curalnder, J., and Kober, W., 1992. Ruke Based System for ThematicClassification in SAR Imagery. Proceedings of IGARSS, IEEE Press,
New YorkeCognition, 2002. User Guide. Definiens Imaging, GmbH, Munich,Germany.
Eguchi, R.T., Huyck,C.K., Houshmand, B., Tralli, D.M., and Shinozuka, M.,
2000. A new Application for Remotely Sensed Data: Construction of
Building Inventories using Synthetic Aperture Radar Technology.
Proceedings of the 2nd Multi –lateral Workshop on Development ofEarthquake and Tsunami Disaster Mitigation Technologies and Their
Integration for the Asia-Pacific Region, Kobe, Japan.
HAZUS 99 Service Release 2 (SR2), User Manual-Arc View, Maryland,
U.S.A.
Padermkul, S.,1999. An Integrated Inventory Methodology for Seismic
Damage Assessment of Bangkok. Asian Institute of Technology,
Thailand, Thesis no. ST-99-29.
Sande, C.J. van der, Jong, S.M. de, and Roo, A.P.J. de, 2003. A
segmentation and classification approach of IKONOS-2 imagery forland cover mapping to assist flood risk and flood damage assessment.
International Journal of Applied Earth Observation and Geoinformation,
vol. 4, pp 217-229.
Tsatsoulis, C., 1993. Expert systems in remote sensing applications. IEEE
Geoscience and Remote Sensing Newsletter June, 7 –15.
Warnitchai, P., 2003. Assessing Impact of Distant Earthquakes on Buildings
and Structures in Bangkok. Proceedings of the 6th Multi-lateralWorkshop on Development of Earthquake and Tsunami Diasster
Mitigation Technologies and their Integration for the Asia-PacificRegion, Kashikojima, Japan.
Warnitchai, P., Sangrayangkul, C., and Ashford, S.A., 2000. Seismic
hazards in Bangkok due to long distance earthquakes. Proceedings ofthe 12th world conference on Earthquake Engineering, Auckland, paper
no. 2145.
Yamazaki, F., Mitomi, H., Matsuoka, M., and Honda, K., 2000. Inventory
Development for Natural and Built Environments- Remote Sensing
Technologies for Inventory Development and Risk AssessmentCharacteristics of Satellite Images in Bangkok, Thailand. Report on‘The Development of Earthquake and Tsunami Disaster Mitigation

Urban Building Inventory from VHR Remote Sensing Imagery for Earthquake Risk Analysis in Bangkok
209

81

October 2004, Agra, India
Technologies and Their Integration For the Asia-Pacific Region,
Earthquake Disaster Mitigation Research Center, Japan.
http://www.edm.bosai.go.jp/eqtap/3rdws_yamazaki_e.pdf(April2004).

82

New Technologies for Urban Safety of Mega Cities in Asia
210

QUANTITATIVE APPROACH FOR
SEISMIC RETROFITTING OF
STRUCTURES USINGPUSHOVER ANALYSISPRABIR C. BASU, A. D. ROSHAN, AJAI S. PISHARADY
Atomic Energy Regulatory Board, Mumbai, India.
adroshan@aerb.gov.in
ABSTRACT
Seismic fragility of structure is the conditional frequency of its failure
for a given value of seismic response parameter, which is generally taken as
peak ground acceleration. A method for determining the seismic fragility
using deflection based structural analysis (pushover analysis) has beendeveloped. Application of deflection based fragility analysis method is
illustrated with an example problem of reinforced concrete frame structures
taken from a safety related concrete building of PHWR based nuclear power
plant.
1.0 INTRODUCTION
Fragility of a system, be it building structures or equipment or a safetysystem, is defined as the conditional probability of its failure for a given
value of the input parameter such as stress, moment, spectral acceleration,
peak ground acceleration.
Seismic fragility is generally defined in terms of peak groundacceleration (PGA). The objective of fragility evaluation is to estimate thePGA value for which the seismic response of a given component (i.e.
structural elements or equipment) located at a specified point in the structure
exceeds the component capacity resulting in its failure. Because there aremany sources of variability in the estimation of this ground acceleration
capacity, the component fragility is described by means of a family offragility curves. A probability value is assigned to each curve to reflect theuncertainty in the fragility estimation (Kennedy et. al., 1980). Systemfragility is derived by combining suitably the component fragility.
In case of structures, failure can be viewed in more than one way,strength failure (collapse) and functional failure. Fragility analysis ofconcrete structure of a nuclear power plant (NPP) is worked out in mostcases in terms of element stresses, i.e. basically with reference to strength
failure. The structures have generally considerable margin against strength
failure. However, safety against such failure may not guarantee the safety
against functional failure.
Seismic fragility of reinforced concrete structures for functional
failure could be worked out using deflection based method. Deflection

107
211

October 2004, Agra, India

based method is also believed to be suitable for re-evaluation of concrete
structures subjected to near field earthquakes. The scope of the present
paper covers determination of seismic fragility of reinforced concrete
structures using deflection based method.
2.0 FRAGILITY ANALYSIS OF STRUCTURAL SYSTEM
The ground acceleration capacity, A, of a component can be expressedin terms of best estimate of the median ground acceleration capacity, Ã, andtwo random variables, R and U, and is given by (Kennedy et. al., 1984),
A = Ă. R. U
Ă = Am. F
F = FS.F.FRS
FRS  FSA  FSS  F  FM  FMC  FEC

(1)
(2)
(3)
(4)

Where,
Ã:Median ground acceleration capacity
R :Random variable representing the inherent randomness about themedian value
U:
Random variable representing the uncertainty in the median value.
Am: Median value of ground acceleration PGA
FS:Strength factor.
F:
Inelastic-absorption factor.
FRS: Structure-response conservatism factor.
FSA: Factor for ground motion and associated response spectra for a given
PGA.
FSS: Soil structure interaction factor.
F:
Factor energy dissipation i.e. damping.
Structural modeling factor.
FM:
FMC: Factor for combination of modes and earthquake analysis results.
FEC: Factor for combination of earthquake components
If {F(.)}’s follows log-normal distribution, the median (F ) andstandard deviation (F) of “F” can be calculated from the median values{F(.) } and logarithmic standard deviation {(.)} of the factors given inequations (3) and (4). Therefore,F  FS  F * FSA  FSS  F  FM  FMC  FEC

(5)

and
2
2
 F  S2  2  SA
 SS
 2   2M   2MC   2EC(6)

F is further divided into random variability R and uncertainty U
The fragility i.e., the frequency of failure f at any non-exceedence
probability level Q can be expressed as:108

New Technologies for Urban Safety of Mega Cities in Asia
212

ICUS Report 6 a ln    U  1 Q  Af  


R







(7)



Where, Q = P f '  f | a = the probability that the conditional frequency offailure, “ f’ ”, is less than f for a peak ground acceleration, ‘a’; and Φ(.) is
the standard Guassian cumulative distribution function. From the equation
above f’ is determined for discrete values of non-exceedence probability
level such as 5%, 50% and 95% etc for each structural elements.
Fragility of the overall structural system can be determined by
combining suitably the component (structural element) fragility. One
example of such combination approach is fail-safe condition. The seismic
fragility of overall structural system can be determined as follows using failsafe combination approach. Let fi is the conditional frequency of failure of
the element for a PGA value of “a”. The conditional frequency failure of
the overall structure for PGA value of “a” is given by the following
expressions (Moses F and Kinser D.E., 1967) for a given value of “i”, say
i = 4;PF = f1+(1- f1)[ f2 + (1- f2){ f3+(1- f3) f4}]

(8)

Where, fi’s are arranged in descending order, i.e., f1 > f2 > f3 > f4
3.0 SEISMIC FRAGILITY OF REINFORCED CONCRETE FRAME
STRUCTURES USING DEFLECTION BASED METHOD

A structure can be considered to fail functionally when the
deformations under seismic loads are estimated to be sufficient topotentially interfere with the operability of the safety related equipment
attached to the structure, or fractured sufficiently to cause the failure ofequipment attached to it. Two important failure modes of structures areindicated above; deformation of the structure beyond a desired value, andfracture of components to which equipment is attached. First one may beviewed from the consideration of functional failure, while the second one isassociated with the strength failure of component.
The functional failure of a structural system can be defined by theexceedence of deflection at a given location beyond a specified value, or
storey drift exceeding a given value. Such type of deflection-based criteria
can be incorporated in the fragility evaluation of reinforced concrete frame
structures by means of deflection-based method.
In deflection-based method, a pushover curve, i.e. load (base shear)
deformation (roof deflection) curve of the structure is first determined andthen the maximum displacement,  ag , under the effect of given seismic
excitation is calculated. Methodology described in either FEMA 273 (1997)

Quantitative Approach for Seismic Retrofitting of Structures using Pushover Analysis
213

109

October 2004, Agra, India

or ATC-40 (1996) is suitable for this purpose. It is to be noted that the
pushover curve (load deformation curve) is the property of the structure andnot related to ground motion parameters. The limiting value of deflection
parameters can be specified considering the constraints imposed upon the
structure from the operability condition of systems or equipment housed init. These limiting values of deflection parameters represent the capacity ofthe structure for given criteria. Typical deflection parameters on which thelimitations could be imposed are roof deflection, storey drift, etc. Once thedeflection parameters are identified and the limits, a, are specified, theground acceleration capacity of the structure can be determined fromequation (1) through (7). The governing relation of ground acceleration
capacity of equations (2) and (3) reduces to

A  A m  FC  FRS(9) a   an
 ag   an

(10)

FC 

Where,
FC = Capacity factor
Δa = Limiting value of structural deflection.
Δan = Deflection induced by non-seismic load
Δag = Maximum deflection corresponds to the given ground motion
parameter determined from the deflection based method.
When an is very small compared to Δ a and Δ ag, for example in case of deadload, equation (10) reduces toFC  a(11)
 ag
It may be noted from equation (9) that the capacity factor FC replaces
Fs and F of equation (3). The factor F of equations (3), (4), and (6) is notconsidered explicitly in equation (9), because the contribution of structuralductility is already considered in establishing pushover curve. But thevariability associated with FC and other factors related to FRS are to beconsidered similar way as expressed in equations (5) and (6). The
exceptions are that the terms ' FS  F ' and '  s2   2 ' would be replaced by‘FC’ and ‘C2’ respectively.
The methodology described in FEMA 273 has been adopted for thepresent work, though ATC-40 methodology is also equally good for
calculating ag. FEMA 273 outlines a procedure for calculation of the
expected maximum displacement (usually, roof displacement), which is also
termed as target displacement, during an earthquake using a number offactors for modification of structural deflection. To derive the target
displacement, the spectral acceleration corresponding to the effective periodof the structure is multiplied by these modification factors, which accounts
for non-linear and dynamic behavior of the structure. The target
displacement expected during an earthquake is given by110

New Technologies for Urban Safety of Mega Cities in Asia
214

ICUS Report 6

2

T 
(12)
 t  C 0 C1C 2 C 3Sa  e  g 2 
The detailed procedure for calculation of target displacement as per
FEMA 273 is given in the Appendix.

4.0 EXAMPLE PROBLEM
The formulation derived in the preceding section is illustrated with an
example of reinforced concrete frame structure taken from a safety relatedbuilding of PHWR based NPP. Figure 1 depicts configuration of the frame
structure and the sectional parameters of beams and columns are given in
Table-1A and Table–1B respectively. The ground acceleration spectrum thatwas used in design of the frame is given in Figure 2.

6.00

5.04

5.86

3.00

6.00

Figure 1:

8.30

6.00

6.75

6.75

7.50

8.50

Configuration of the frame structure of the example problem(All dimensions are in meters)
Table 1A: Section parameters of beams

Group
B1
B2
B3
B4
B5
B6
B7
B8
B9
B10
B11
B12

Element Numbers.

Size
Percentage of reinforcement
End 1
End 2
(mm)
bxd
Top Bottom Top Bottom
231
450x1000 .84
.84
.88
.88
237
450x1000 .78
.78
.87
.87
232,234,236
450x1000 .66
.66
.67
.67
233,235450x1000 .74
.74
.76
.76
245,238800x500 1.82
.61
1.3
.65
244
500x1200 .91
.54
1.26
.55
239
500x1200 1.22
.61
.92
.56
240,241,242,243
500x1200 .99
.61
.95
.62
252
800x500 1.16
.61
.95
.62
246
700x1200 .95
.6
.7
.54
247,248,249,250,251 700x1200 .65
.55
.67
.59
253,254,255,256,257 700x950
.85
.55
.88
.61

Quantitative Approach for Seismic Retrofitting of Structures using Pushover Analysis
215

111

October 2004, Agra, India

Table 1B: Section parameters of columns
Group

Element Numbers

Size (mm)

C1
C2
C3
C4
C5
C6

201
202, 204203
205, 206, 207
208
209, 210, 211, 213, 214,
215, 216, 217, 218, 220,
221, 222, 224, 225, 226
212, 219
223, 227
228, 229, 230

800x800
800x800
800x800
1200x1200
1200x1200
1000x1000

Percentage ofreinforcement
3.5
2.42
1.27
1.26
1.45
1.62

1000x1000
1000x1000
1200x1200

1.97
1.89
1.26

C7
C8
C9

Spectral Acceleration, g

0.6
0.5
0.4
0.3
0.2
0.1
0
0

1

2

3

4

Period, sFigure 2: Ground acceleration response spectra (7% damping)
Push over analysis of the frame was carried out for failure in flexuremode. The moment curvature relationship of elements are determined fromthe cross sectional data of Table-1 using the method given in (SS/CSE-1).
A typical moment curvature relation of a concrete beam (end 1 of element
group B2) is shown in Figure 3. The fragility parameters, i.e. median valuesof factors associated with FRS and the variability of FC and different factors
related to FRS is tabulated in Table – 2 (Kennedy et. al., 1984).
Table 2: Fragility Parameters

112

Factors

F(.)

(.)U

(.)R

FC
FSA
Fδ
FM
FMC
FEC
FSS

1.25
1.25
1.0
1.0
1.0
1.3

0.25
0.10
0.075
0.15
0.00
0.00
0.20

0.14
0.20
0.075
0.00
0.075
0.075
0.20

New Technologies for Urban Safety of Mega Cities in Asia
216

ICUS Report 6

3.E+06

Moment (N-m)

2.E+06
2.E+06P=0

1.E+06

P=10%Pu
5.E+05

P=50% Pu

0.E+000

0.005

0.01 0.015 0.02
Curvature (rad/mm)

0.025

0.03

Figure 3: Typical moment curvature curves for a concrete beam fordifferent values of axial load (P) in terms of ultimate load (Pu)The frame was pushed by the load distribution given in Figure 4,
determined from storey shear corresponding to first mode of vibration. The
push over analysis was carried out using ANSYS software. Figure 5
contains the deflected shape of the frame when mechanism is formed. The
corresponding pushover curve, i.e. variation of roof displacement with baseshear is given in Figure 6. The load displacement data obtained from thepushover analysis is given in Table-3.
Storey Height, m

25
20
15
10
5
0
0

1

2

Ratio of applied floor loads

Figure 4: Load distribution used for pushover analysis

Figure 5: Deflected shape of the frame after the formation of mechanism.

Quantitative Approach for Seismic Retrofitting of Structures using Pushover Analysis
217

113

October 2004, Agra, India

Base Shear, N

6.0E+06
5.0E+06
4.0E+06
3.0E+06
2.0E+06
1.0E+06
0.0E+00
0.000

0.050

0.100

0.150

0.200

0.250

Roof displacement, mFigure 6: Pushover curve (Base shear Vs roof deflection) of the frame
Table 3: Load – Load – deflection data of the frame
Step Base shear,
Roof
Fourth floor
No.
(N)
Floor Drift, Drift Ratio Floor Drift, Drift ratio,
(m)
%
(m)
%
1
1.46E+05
0.00320.01620.00100.016022.82E+05
0.00610.03070.00180.02963
4.86E+05
0.01040.05250.00300.04994
7.58E+05
0.01620.08160.00460.07715
1.03E+06
0.02200.11080.00630.10446
1.30E+06
0.02790.14000.00790.1317
7
1.57E+06
0.03370.16930.00950.15918
1.85E+06
0.0395
0.19860.01120.186792.12E+06
0.04540.22790.01280.214210
2.39E+06
0.05120.25720.01450.2417
11
2.66E+06
0.05700.28660.01620.269212
2.93E+06
0.06290.31610.01780.296813
3.21E+06
0.06880.34590.01950.324514
3.48E+06
0.07490.37630.02110.352415
3.75E+06
0.08100.4071
0.02280.380416
4.02E+06
0.08730.43870.02450.408917
4.29E+06
0.09400.47220.02630.437918
4.57E+06
0.10110.50800.02810.467719
4.84E+06
0.1091
0.54820.02990.498920
5.11E+06
0.11750.59030.03180.530721
5.38E+06
0.21001.05530.04070.6779The median value of FC, i.e. F C, is calculated from the medianvalue of a and ag using equation (11). The corresponding value ofvariability CR and uncertainty CU are taken as 0.14 and 0.25 respectively.
The displacement, ag, corresponding to PGA value 0.2g is calculated fromequation (12) and the pushover curve of Figure 6, which is 9.44 mm. The
fragility curve considering the value of maximum roof deflection, a=
210mm (from Figure 6) as its capacity is given in Figure 7. It may be notedthat Figure 7 gives the fragility curve of the frame when its capacity is

114

New Technologies for Urban Safety of Mega Cities in Asia
218

ICUS Report 6

Conditional frequency of failure

defined by the maximum roof deflection. The acceleration capacity of theframe corresponding to high confidence (95%) low probability of failure(5%) is 2.8g.
1.20

Q : 5%

1.00

Q: 50%

0.80

Q: 95%

0.60
0.40
0.20
0.00
0

2

4

6

8

10

12

Acceleration (g)Figure 7: Fragility curve of the frame corresponding to the collapse state.
HCLPF = 2.8g

Conditional frequency of failure

The pushover calculation of the frame indicates a very high roof
deflection 210mm prior to collapse, no concrete structure of NPP is allowed
to deflect so high. Generally limit on deflection, from functionality
consideration, is imposed. The fragility curves of structure can be easily
determined for this condition. If roof deflection of the example frame islimited to height/300, the Δa becomes 66mm. This is less than the
maximum defection determined by pushover analysis. The fragility curves
thus determined by putting this value of Δa in equation (9) and (11) are
given in Figure 8.
1.20

Q: 5%

1.00

Q: 50%

0.80

Q: 95%

0.60
0.40
0.20
0.00
0

2

4

6

8

10

12

Acceleration (g)Figure 8: Fragility curve of the frame corresponding to the roof deflectionof height/300, HCLPF= 0.875 g.
Functional failure criteria are also defined in some cases by limiting
particular storey drift. Fragility curves can also be determined for suchcases using the method described in the present paper. If functional failure
is defined as a given floor drift, the roof deflection corresponding to thisspecified floor drift will represent the capacity Δa. Once Δa is known, thefragility curves are determined using the same procedure. Fragility curvesof the example problem are determined for four cases of story drifts as given
in Table-4. These fragility curves are given in Figure 9.

Quantitative Approach for Seismic Retrofitting of Structures using Pushover Analysis
219

115

October 2004, Agra, India

Table 4: Calculation of Fc for different performance parametersCase(% drift of second
floor)
1
0.75
0.5
0.25
1.20
1.00
0.80
0.60
0.40
0.20
0.00
0

5
10
Acceleration (g)Conditional frequency
of failure

Conditional frequency
of failure

1
2
3
4

Roof deflection,Δa* (m)
0.164
0.125
0.085
0.037

15

0

Fragility

Conditional frequency offailure

0.60
0.40
0.20
0.00
10

17.32
13.06
9.00
3.87

3.64
2.61
1.80
0.77

5
10
Acceleration(g)15(b) Case – 2 (drift = 0.75%)
HCLPF = 1.65g

1.20
1.00
0.80

5

Am Fc (g)

1.20
1.00
0.80
0.60
0.40
0.20
0.00

(a) Case – 1 (drift = 1%)
HCLPF = 2.175g

0

Fc

15

1.20
1.00
0.80
0.60
0.40
0.20
0.00
0

Acceleration (g)(c) Case – 3 (drift = 0.5%)
HCLPF = 1.125 g

5

10

Acceleration (g)(d) Case – 2 (drift = 0.25%)
HCLPF = 0.485 g

Figure 9: Fragility curve of the frame corresponding to limits
on floor drift
5.0 CONCLUDING REMARKS
Deflection based method has been in use for the safety assessment ofreinforced concrete structures of buildings in non-nuclear field for sometime. This method is believed to be an efficient tool for examining safetysignificance of structures subjected to near field earthquakes in addition tothat for far-field earthquake.
A formulation, using deflection based method, is outlined in thepresent paper to calculate the fragility curves of reinforced concrete
structures when failure criteria is described in terms of deflection parametersof structure. The newly formulated deflection based method for fragility
analysis is applied to determine the fragility curves of the example problem
conveniently with the failure criteria is expressed as follows,

116

New Technologies for Urban Safety of Mega Cities in Asia
220

ICUS Report 6Roof deflection at collapse of structure
Limit on roof deflection expressed as a fraction of height of thebuilding
Storey drift

Further work is necessary to assign suitable value of different fragility
parameters, i.e. F(.) , ( . ) U and  ( . ) R .
REFERENCES
Applied Technology Council. Seismic Evaluation and Retrofit of concretebuildings. ATC-40 (1996), Vol. 1, California Seismic Safety
Commission, California.
Atomic Energy Regulatory Board. Design of Concrete Structures Important
to Safety of Nuclear Facilities. SS/CSE-1 (2001), AERB, Mumbai.
Federal Emergency Management Agency. NEHRP Guidelines for the
Seismic Rehabilitation of Buildings. FEMA-273 (1997), Washington,
DC.
Kennedy R.P., Cornell C.A., Campbell R.D., Kaplan S., Perla H.F., 1980.
Probabilistic seismic safety study of an existing nuclear power plant.
Nuclear Engineering and Design, 59, 315-338.
Kennedy R. P., Ravindra M.K.. Seismic fragilities for nuclear power plantrisk studies. Nuclear Engineering and Design, 79, 47-68.
Moses, F., Kinser, D.E.. Optimum structural design with failure constraints.
AIAA Journal, 6 (1967), 1152-1158
U.S. Nuclear Regulatory Commission. Assessment of the Relevance ofDisplacement Based Design Methods/Criteria to Nuclear Plant
Structures. NUREG-6719 (2001), USNRC, Washington DC.

Quantitative Approach for Seismic Retrofitting of Structures using Pushover Analysis
221

117

October 2004, Agra, India

APPENDIXCALCULATION OF TARGET DISPLACEMENT AS PER FEMA 273
FEMA 273 outlines a procedure for calculation of the expected maximum
displacement (usually, roof displacement) during an earthquake. For this purpose, thespectral displacement corresponding to the effective period of the structure ismultiplied by a series of coefficients, which accounts for non-linear behavior of thestructure. The procedure could be briefly described as follows:1.
2.

Calculate the fundamental period (Ti) of the structure
From the non-linear force displacement curve (Base shear vs. roof displacement),
derive a bilinear form of force displacement curve. The intersection of the twolinear segments is termed as the yield strength of the (Vy) of the structure. The
bilinear segments should also satisfy the criterion that the first segment of thebilinear approximation should intersect the non-linear curve at a base shear of
0.6Vy. The initial slope of the bilinear curve is termed as effective lateral stiffness,
Ke (Figure A1). The effective period of the structure isTe  Ti

Ki
Ke

Ki : Elastic lateral stiffness of the building.
3.

The target displacement (t ) is given by2

T  t  C 0 C1C 2 C 3 Sa e  g 2 
Where
Sa is the spectral acceleration at period, Te, and the damping ratio of the building
under consideration
C0 is the modification factor to relate the spectral displacement and likely building
roof displacement.
C1 is the modification factor to relate expected maximum inelastic displacements todisplacements calculated for linear response.
C2 is the modification factor to represent the effect of hysteresis shape on the
maximum displacement response.
C3 is the modification factor to represent the increased displacements due to dynamic
P- effects.

Figure A1: Calculation of effective stiffness (From FEMA 273)

118

New Technologies for Urban Safety of Mega Cities in Asia
222

EVALUATION OF EARTHQUAKE CAUSEDDAMAGES USING NON-LINEAR
DYNAMIC ANALYSIS
T.G. SUNTHARAVADIVEL1, YOZO FUJINO1 AND PING ZHU2
1
The University of Tokyo, Tokyo, Japan.
2
Research Institute of Science and Technology for Society, Tokyo, Japanzhu@ristex.jst.go.jp
ABSTRACTThe inter-dependent socio-economic development of the world has led
to dramatic increase of losses due to natural and anthropogenic
catastrophes such as earthquakes, floods, and nuclear accidents. The everincreasing loss and casualty of earthquakes in the past several decades havewarranted commitments and cooperative endeavors by the insurance sector,
as well as the emergency management agencies at a national andinternational level, toward reducing the loss and casualty caused byearthquake disasters.
This paper focuses on the analysis of damage of wooden house using
numerical simulation. In Japan, the wooden house represents one of thesociety’s largest investments in the built environment and common wood
frame house is usually an individual’s largest assets. But the wooden
houses have higher risk during an earthquake. During the Great Kanto
earthquake (1923) and Kobe Great Hanshin Earthquake (1995) many
human casualties are associated with the wooden residential houses. So thatthe wooden houses damage have a significant role in risk assessment inJapan cities and need to estimate the damage of wooden houses with moreconcern. However unlikely other type of structures, the wooden houseseismic behavior is highly affected by many uncertainties such as joint type,material properties of timber. In this study an advanced technique has beenused to simulate the wooden houses and study the effect of the joint
properties and building type on the damage of a wooden house. The
influence of joint strength on the damage of wooden houses has discussed.
1.0 INTRODUCTION
Earthquake cause a large impacts on human properties and life as well.
However its occurrence time and place or magnitude could not predict
exactly with existing technology. This critical situation makes a higher
demand in pre-earthquake damage and loss assessment to reduce thedamages of human life and properties. It has been estimated that within thenext 50 years, more than a third of the world’s population will live inseismically and volcanically active zones (Serguei et al. 2002). Therefore aproper risk management policy is important to serve the building damage
and human vulnerability. To achieve this aim, an effective methodology isneeded to estimate the building damage caused by an earthquake. The

119
223

October 2004, Agra, India

seismic hazard assessment (estimate the building and human vulnerability)
methodology consists of several steps, some of which are interactive. In
general these events are treated separately and combining together in aprobability manner to get total damage and loss due to an earthquake
scenario.
Unlikely other type of structures, wooden houses behavior is highly
complex and varies with their material properties and dynamic
characteristics as well as the scenario earthquake. Therefore the statistical
data or probabilistic based estimation will not satisfy the decision makers’
demand. Thus, a numerical based damage estimation system is important forbuildings, especially for wooden houses.
2.0 MODELING OF WOODEN HOUSES
2.1 Background
Wood structures consist of interacting components (or subassemblies)
such as walls, floors, roof, and a foundation that are fastened together bynails, bolts, steel straps, and/or cleats forming a three – dimensional, highly
indeterminate system. A common observation from the cyclic test data oftypical lateral – load – resisting systems is that the hysteresis trace of woodsubsystem or subassembly is governed by the hysteretic characteristics of its
primary connections. Thus, we only need to characterize the hysteretic
behavior of wood joints to characterize the behavior of wood structural
systems (Greg C. Foliente, 1995).
In Japan several models have been used in dynamic analysis ofJapanese wood houses. Sakamoto and Ohashi (1998) proposed two
hysteresis models for conventional Japanese wooden houses. Kamiya (1988)
proposed another model that was developed from pseudo–dynamic tests ofwood – sheathed shear walls. A third model was proposed by Miyazawa(1990) for Japanese wood – framed construction.
2.2 Numerical tool – DEM
Although these models satisfied some of the specific features of thejoints or systems that they meant to model, they may be inappropriate forjoints and systems with different configurations and material components.
Furthermore, all the available models for wooden systems use either acomplex set of force – history rules or very limited empirical relations.
Because there are hundred of combinations of materials and joint
configurations in wood systems a general constitutive model, that both
simulates the general hysteretic features of wooden systems and ismathematically tractable in dynamic analysis is preferred.
Junji Kiyono and Aiko Furukawa (2004) developed three –dimensional analytical model using distinct element model (DEM). The
main advantage of this DEM is that, it can analyze until the collapse of the120

New Technologies for Urban Safety of Mega Cities in Asia
224

ICUS Report 6

house (DEM is a numerical analysis method that compute the position ofeach individual elements by solving equations of motion step by step) andable to simulate collapse of each element individually as well. In usual
DEM, connectivity between elements is not considered, the elements acting
independently as a discontinuum. Joints, however, connect the columns andbeams of a real structure, and the structure acts as a continuum. The contact
model (Figure 1) allows a structure to behave as a continuum until its joints
being broken.

Figure 1: Contact Models of Elements (2D)The joint model consists of spring and dashpot to represent therespective hysteretic loop of the wooden houses. However, in this analysis
it is assumed that damping coefficient of the joint model as zero in all
directions and springs behave as bilinear elastic - plastic elements.
3.0 NUMERICAL ANALYSIS OF WOODEN HOUSESIn this study, wooden houses were modeled using DEM. Because of
the number of combination in the materials as well as joint configurations,the damage may differ significantly even with same structuralconfigurations. The major sources for the variation in the damage ofwooden houses were identified as:Earthquake Input – for same spectral displacement depends on the
input earthquake motion may change the response of the buildings.
Type of building – different type (frequency) of structure has
different response for same earthquake.
The joint property of the wooden houses – Type and configurationof joints [for analytical purpose Dowrick (1986) classified joint
types into yielding plates, yielding nails and yielding bolts]

3.1 Input parameters
A number of two story wooden buildings were analyzed for 1995
Kobe earthquake ground motion with different joint strengths. In reality
wooden house joint strengths have a large range from 4000 – 12000 N/m2
(Sarwar, 2003) depends on the material properties, age and joint
configuration. According to the IISEE report about wooden houses, theEvaluation of Earthquake Caused Damages Using Non-Linear Dynamic Analysis
225

121

October 2004, Agra, India

natural frequencies have changes from 2.2 – 4.0 Hz. Based on these studies
following range of joint strengths and frequencies has used for this study.

Figure 2: Typical plan of wooden house used in this study
Table 1: Model properties for the analysis
Model Property
Joint Strength (N/m2)
Natural Frequency (Hz)Range
4500 – 25000
2.5 – 4.0

3.2 Simulation results
The story drift angle (story drift divided by the height of the story) was
obtained from the numerical simulation as a measure of damage. The mean
and variation is plotted in Figure 3.

122

New Technologies for Urban Safety of Mega Cities in Asia
226

ICUS Report 6

Figure 3: Story drift angles for different joint strengths
4.0 DAMAGE ANALYSIS OF WOODEN HOUSESThe simulation results show a large variation of story drift angle
measurement in low joint strength range. Most of the residential houses in
Kobe were on this range and served a severe damage.
4.1 Damage classification
Because of the higher variation of the story drift angle (damage) inwooden houses, the mean value of damage may leads a large difference indecision-making towards improve the building performance. However to
use the numerical simulation result for damage estimation we need arelationship between story drift angle and damage of wooden houses. Basedon the post earthquake assessment guidance used in Japan, we proposed a
simple relation as in Figure 4. The story drift 1/5 is considered as limit ofsafety of the building.

Figure 4: Defined relationship between story drift angle anddamage of wooden house

Evaluation of Earthquake Caused Damages Using Non-Linear Dynamic Analysis
227

123

October 2004, Agra, India

4.2 Damage distributions
The wooden house damages were estimated for different wooden
house groups. According to Sarwar (2003), Joint strengths of Kobe wooden
houses having a mean of 6000 N/m2 and standard deviation (STDIV) 1050
N/m2. Based on this other joint strength distributions were assumed to study
the effect of joint strength on the damage of wooden houses.
Table 1: Distribution of wooden house damage with different joint strength
distributions
Joint Strength (N/m2)
Mean
STDIV
6000
1050
7000
1300
8000
1450
9000
1600

Mean
58.0
45.9
28.7
22.1

Damage (%)
STDIV
43.3
32.5
28.5
21.0

According to the analytical results, when the joint strength increased
by 50%, the damage of wooden houses could be reducing by nearly 60%.
This is an important advantage in numerical damage estimation; it is easy to
predict the future retrofitting scheme for a wooden house or a group ofwooden houses.
5.0 CONCLUSIONSIn this paper, the earthquake caused damage and loss of wooden
houses was analyzed using non-linear dynamic response analysis. The
variation in the conventional damage estimation methodology has discussed
for different joint properties and different wooden house types. A numerical
based damage estimation methodology has been developed. This study canconclude that:

There is a large variation observed in the damage of wooden
houses for different joint strengths and different natural frequencyof the structures. In reality the joint strength of wooden house hasa large range depending not only on the age of the structure but
also in the joint type and timber properties.
The story drift angle could be a better measure than the fragility
curve for more reliable damage estimation. With the advanced
computation technology the story drift angle can be estimated in ashort time with good accuracy.
The numerical computation also gives a better estimation of thehuman vulnerability (not discussed in this paper).

At present the existing wooden houses were not strictly follow code ofpractice; therefore, the material and joint properties are highly unknown.
Therefore it is quite difficult to categorize into groups. Therefore numerical124

New Technologies for Urban Safety of Mega Cities in Asia
228

ICUS Report 6

analysis methodology is a better replacement for the conventional damage
estimation (fragility curve) of wooden houses. It can be estimate thestability of the wooden frame construction as well as effect of retrofitting.
ACKNOWLEDGEMENTS
The authors wish to thank Professor Muneo Hori and Dr. Masato Abe
for thier guidance and patient advice during this study.
REFERENCES
American Institute of Timber Construction, 1966. Timber Construction
Manual. AITC, Washington, D.C.
Applied Technology Council, 1985. Earthquake Damage Evaluation Data
for California. ATC, California.
Disaster Presentation Urban Development Section, 2002. The Fifth Reporton Disaster – based Assessment of Vulnerability to Earthquake Disaster.
Bureau of City Planning, Tokyo Metropolitan Government, Japan
Dowrick, D.J., 1986. Hysteresis loops for Timber Structures: Bulletin of
New Zealand National Society of Earthquake Engineering. Waikanoe,
New Zealand, Vol. 19(20), 143-152.
Federal Emergency Management Agency 1999. HAZUS®99 Technical andUser Manual. FEMA, Washington D.C.
Greg C. Foliente, 1995. Hysteresis Modeling of Wood Joints and Structural
Systems”, Journal of Structural Engineering. Vol. 121(6), 1013–1022.
International Institute of Seismology and Earthquake Engineering.
Assesment of Building Damage due to Ground Motion. Web publicationof
IISEE,
http://iisee.kenken.go.jp/net/yokoi/methodology/
04bld_damage_motion.htm
Junji Kiyono, and Aiko Furukawa, 2004. Casualty Occurrence Mechanismin the Collapse of Timber – frame Houses during an Earthquake
Earthquake Engineering and Structural Dynamics. Vol. 33, 1233–1248.
Naoya Yamaguchi, and Fumio Yamazaki, 2001. Estimation of strong
motion distribution in the 1995 Kobe earthquake based on building
damage data. Earthquake Engineering and Structural Dynamics. Vol. 30,
787– 801.
Osamu Murao, Hiroyuki Tanaka, and Fumio Yamazaki, 2000. Risk
Evaluation Method of Building Collapse from the Experience of theKobe Earthquake. Proceedings of the 12th World Conference on
Earthquake Engineering, Auckland New Zealand, January 2000.
Sarwar Muhammad Waheed, 2003. Parametric Identification of Joints in
Wooden Houses based on Past Earthquake Damage using DEM
Collapse Simulation. Master Thesis, University of Tokyo, Japan.
Serguei Baranov, Boris Digas, Tatiana Ermolieva, Valerii Rozenberg, 2002.
Earthquake Risk Management: A Scenario Generator. Interim Report of
the Project No IR-02-025, International Institute for Applied Systems
Analysis, Austria. http://www.iiasa.ac.at

Evaluation of Earthquake Caused Damages Using Non-Linear Dynamic Analysis
229

125



SEISMIC BEHAVIOR OF URBAN HIGHWAY
TUNNEL IN VICINITY OF EMBANKMENTYUSUKE ONO, JUNJI KIYONO AND TATSUKI TAMAI
Department of Urban Management, Kyoto University, Japan
ono@quake2.kuciv.kyoto-u.ac.jp

ABSTRACTA new construction of the highway tunnel is planned in Osaka, Japan.
The features of this structure are that it is a semi-underground structure andin the vicinity of the existing embankment. The steel sheet piles will be
installed on the both sides of the tunnel during the construction. The seismic
responses of both the highway tunnel and the embankment may decrease
due to the large stiffness of steel sheet piles. The sheet piles, however, areusually removed after the construction and their effects on the seismic
responses are not cleared yet. Thus, effects of the steel sheet pile on theseismic behavior of the semi-underground highway tunnel and theembankment are discussed in this paper.
The three-dimensional dynamic finite element technique is used to
calculate earthquake responses. Our analysis is composed of two steps.
First, the earthquake ground motions are inputted below the bottom of thefinite model spontaneously. Second, the input ground motions are appliedalong the longitudinal direction with time delay and the propagation effects
of seismic waves are considered.
It is concluded that the steel sheet pile installed the both side of thetunnel have effects that make the residual displacement and the rocking ofstructure decrease. Furthermore, it is cleared that the effects of the sheet
pile are strongly affected by the propagating velocity of the seismic wave.
1.0 INTRODUCTION
A new highway construction is planned due to the dissolution of theheavy traffic jam in Osaka region. The part of this new highway will be ahalf-buried structure and combined with the existing embankment. Few
construction examples of tunnel structures combined with the embankment
are known and the seismic behavior of this kind of system has not beencleared yet.
Moreover, the steel sheet piles are planned to be installed along theboth sides of the half-buried tunnel. The steel sheet piles are generally usedas the temporally retaining wall during the construction and they are
removed when the construction is finished. However, it is expected that the
sheet piles improve the stability of the embankment during earthquakes.
The purpose of this study is to investigate the seismic behavior of thehalf-buried tunnel-embankment system with steel sheet piles, and to make

127
230

October 2004, Agra, Indiaclear the propagation effect of the input ground motions. Three dimensional
finite element analysis is used in this study.
2.0 ANALYTICAL MODEL
In this study, the viscous boundary developed by Miura et al (1989)
was used. The viscous boundary we used can take into account the free field
ground motion on the outside of the analytical region. Soils including theembankment were modeled as an elastic-plastic solid element except forbase diluvial clay while the tunnel structure was modeled as elastic solid
element. The steel sheet pile was modeled as a Mindlin shell element. The
yield criterion of soil element obeys the Drucker-Prager model. The
geological survey at the construction site has already been done. The soil
properties we used are listed in Table 1.
Table 1: Soil profiles

Soil

Unit
Weight(tf/m3)

Poisson’s
ratio

B-1
B-2
As
Ac-1
Ac-2
Tc

1.90
1.78
1.89
1.79
1.75
1.83

0.490
0.384
0.494
0.493
0.492
0.492

Shear
Wave
Velocity
(m/s)
200.0
200.0
153.0
157.0
194.0
218.0

Cohesion(tf/m2)
0.00
0.86
0.88
7.15
7.64
12.8

Internal
Friction
Angle
(deg)
35.0
37.4
35.7
0.0
0.0
0.0

The sectional view of the tunnel-embankment system is illustrated in
Figure 1. As shown in Figure 2, the steel sheet piles are installed in the bothside of 1m away from the structure. The embankment consists of two soilmaterials. Properties of the embankment materials were also shown in Table
1. The half-buried tunnel is a reinforced concrete structure. The properties
are shown in Table 2. The unit weight, Poisson ratio and Young's modulus
of steel sheet pile are also shown in Table 2.
Table 2: Structural parameters
Structure
RC tunnel
Steel Sheet Pile

Unit Weight(tf/m3)
2.35
7.85

Poisson’s
ratio
0.167
0.300

Young’s Modulus(tf/m)
2.8x106
2.1x107

The FEM mesh used in this analysis is shown in Figure 3. The widthand depth of the analytical model in the cross section are 233m and 38.5m,
respectively. The length of longitudinal section is 300m.

128

New Technologies for Urban Safety of Mega Cities in Asia
231

ICUS Report 6



Figure 1: Sectional view of the half-buried tunnel and theembankment

Figure 2: Soil profiles and installation position of steel sheet piles

Figure 3: Bird view of finite element mesh
3.0 INPUT GROUND MOTION
Figure 4 shows the time histories of the observed records at the PortIsland during the 1995 Kobe Earthquake. The vertical seismographs array
had been built at the site. The records at G.L.-83m are used in our analysis.
Three components of the ground motion are inputted simultaneously.

Seismic Behavior of Urban Highway Tunnel in Vicinity of Embankment
232

129

October 2004, Agra, India

NS Comp.

EW Comp.

UD Comp.

Figure 4: Observed record at G.L.-83m, Port Islands during
1995 Kobe earthquake.

4.0 RESULTS
4.1 Effects of steel sheet pile
The horizontal responses at the top of the embankment in the crosssection which locates at center of the longitudinal direction are shown in
Figure 4. The responses are obviously reduced by leaving steel sheet piles.
The reduction rate of the maximum acceleration is 12.3%. With respect tothe peak values of the velocity and the residual displacement, the reduction
rates are 14.6% and 56.3% respectively.
On the other hand, the vertical direction responses of the same node
are shown in Figure 5. Although the remarkable reduction is not seen about
acceleration and velocity responses, the residual displacement is decreased
by steel sheet piles. The reduction rate due to the steel sheet piles is 47.8%.
Table 3 shows the summary of the comparison of the peak values of
the acceleration, velocity and residual displacement with and without thesteel sheet piles. It is known that the horizontal responses in the crossdirection and the residual vertical displacement are decreased. Thisphenomenon is also seen at the top of the half-buried RC tunnel.

130

New Technologies for Urban Safety of Mega Cities in Asia
233

ICUS Report 6



Acc.

Vel.

Dsp.

Figure 4:

Horizontal responses at the top of theembankment in the cross section

Table 3: Peak values of responses at the top of the embankment
Acc. (gal)Vel. (kine)

Residual Dsp.
(cm)

Horizontal response in the cross section
without steel sheet pile1228.1
163.6
with steel sheet pile1069.3
139.6
Horizontal response in the longitudinal section
without steel sheet pile
690.7
84.4
with steel sheet pile680
86.4
Vertical Response
without steel sheet pile382.8
22with steel sheet pile
400.6
31.7

13.38
5.84
1.09
2.82
1.68
0.88

Figures 5(a) and (b) show the growth of the yielded soil area in thecase without and with steel sheet pile in the cross section at the center of
longitudinal direction, respectively. These results show that the steel sheet
piles have effects of increasing the shear strength of soil closed between
steel sheet piles. Figures 6(a) and (b) show the spatial distribution of the
maximum strain in the case without and with steel sheet piles, respectively.
It is found that the axial strains near the surface are decreased by the steel
sheet piles. On the other hands, the axial strains in the depth deeper thansheet piles are increasing as compared with the case without steel sheet piles.
Additionally it is seen that strains in the region between the tunnel andthe embankment is quite small. This phenomenon implies that the structure

Seismic Behavior of Urban Highway Tunnel in Vicinity of Embankment
234

131

October 2004, Agra, India




5.6s

5.8s

6.0s

(a) Without steel sheet piles

5.6s

5.8s

6.0s

(b) With steel sheet piles
Figure 5: The growth of the yielded soil area

exx

ezz

ezx

(a) Without steel sheet piles

exx

ezz

ezx

(b) With steel sheet piles
Figure 6: Distribution of the maximum strain

and embankment behave as one structure. The maximum value of strain ezx
is reduced by 50% by the steel sheet piles and the steel sheet piles restrain
the share deformation of the soil in the cross section.
Figure 7 shows the behavior of the structure from 5.9 to 6.05 sec. The
nodal displacements are multiplied by 300 and the results without steel sheet
piles are shown. On the other hands, Figure 10 corresponds to the case withsteel sheet piles. Compared with these figures, it is found that the rocking ofstructure is decreased by the steel sheet piles. In vertical component, the132

New Technologies for Urban Safety of Mega Cities in Asia
235

ICUS Report 6

residual relative displacement between the both ends of the bottom is0.47cm with steel sheet piles while it amount to 2.8cm in the case withoutthem. This is because steel sheet piles restrain the deformation of the soil
under the structure. We can conclude the steel sheet piles have desirable
effects that make the rocking of the structure decrease.
4.2 Propagation effects of input ground motion
Each part of a long structure, like as a highway tunnel, is excited by adifferent input motion each other and it becomes a problem on a seismic
performance of a structure. Thus the responses of our highway tunnelembankment system excited by the propagating seismic wave are analyzed
in this study.
Figure 8 shows the nodal responses at the top of the embankment in
the case without the steel sheet piles while the propagation velocity of the
input wave change from 500 to 1000 and 2000m/s. In this figure, themaximum response is getting smaller when the propagation velocity
becomes small.
Figure 9 and 10 show comparison of the nodal responses at the top of
the embankment between the case with and without the steel sheet piles.
The propagation velocity in Figures 9 and 10 are corresponding to 500 and
2000m/s respectively. From these figures, it can be seen that the steel sheet
piles have small effect on the response of the embankment as long as the
propagation velocity is small.
5.0 CONCLUSIONS
The dynamic behavior of the embankment neighboring on semiunderground structure excited by the seismic motion is discussed. The
conclusions obtained through this study are summarized as follows:

By installing the steel sheet piles along the tunnel structure, themaximum values of horizontal acceleration and velocity on the
cross section are decreased 10% at least.
The steel sheet piles have effects that make the residual
displacement and the rocking of the structure decrease.
Taking into account the propagation of seismic waves, themaximum response both of the structure and the embankment
become small.
The effects of the steel sheet piles become small when the
propagation velocity is getting small.

Seismic Behavior of Urban Highway Tunnel in Vicinity of Embankment
236

133

October 2004, Agra, India(a) Without steel sheet piles(b) With steel sheet piles
Figure 7: Rocking motion of the RC tunnel

Vel.

Acc.

Dsp.

Figure 8: Variation of the response at the top of the embankment
due to the propagation velocity of the input motion

134

New Technologies for Urban Safety of Mega Cities in Asia
237

ICUS Report 6



Acc.

Vel.

Dsp.

Figure 9: Effect of the steel sheet piles (V=500m/s)

Acc.

Vel.

Dsp.

Figure 10: Effect of the steel sheet piles (V=2000m/s)

Seismic Behavior of Urban Highway Tunnel in Vicinity of Embankment
238

135

October 2004, Agra, India

REFERENCES
Miura, F and Okinaka, H, 1989. Dynamic Analysis Method for 3-D SoilStructure Interaction System with the Viscous Boundary based on the
Principle of Virtual Work. Journal of Structural Engineering, JSCE,
No404, pp.395-404.

136

New Technologies for Urban Safety of Mega Cities in Asia
239

SEISMIC BEHAVIOR OF REINFORCED
CONCRETE PIERS DETERIORATED BY
CORROSION OF REINFORCEMENT
KOJI TAKEWAKA1 AND GOVINDA RAJ PANDEY2
1
Kagoshima University, Japan
Saitama University, Japan
takewaka@oce.kagoshima-u.ac.jp
ABSTRACTThe corrosion of reinforcement is the main cause of serious and rapid
degradation of the performance of reinforced concrete structures. Apartfrom the problems on serviceability such as cracking and rust staining,
corrosion on reinforcement causes significant deterioration in the static anddynamic behavior of the reinforced concrete structures leading to the
reduction of their mechanical capacities.
The main objective of this research is to evaluate the seismic
behaviors such as, stiffness, ductility and energy absorption of the piers
deteriorated by corrosion of reinforcement. It is aimed to obtain the natureof degradation of these properties with increase in the weight loss ofreinforcing steel due to corrosion. Moreover, the combined effect of theaxial load and the corrosion is also to be evaluated.
In the examination, an experimental study is carried out on sixteen
reinforced concrete piers with exactly same size and identical loading
cycles while axial load, design method and corrosion condition were being
varied. And, the following results can be obtained:
The seismic behaviors of reinforced concrete structures areseriously affected by corrosion of reinforcement, and the reduction
rate of strength, ductility and total energy absorption withcorrosion loss of reinforcement can be quantitatively evaluated byexperimental equations.
Rate of degradation of ductility and energy absorption withcorrosion loss is found to be much larger than that of strength.
Therefore, even when only a slight reduction of strength ofstructure due to corrosion of reinforcement has been observed
from static loading test, it should be considered that the corrosion
is responsible for much larger reduction of ductility and energy
absorption.
1.0 INTRODUCTION
The corrosion of reinforcement is the main cause of serious and rapid
degradation of the performance of reinforced concrete structures. Apartfrom the problems on serviceability such as cracking and rust staining,

139
240

October 2004, Agra, India

corrosion in reinforcement causes significant deterioration in the static anddynamic behavior of the reinforced concrete structures leading to the
reduction of their mechanical capacities.
Experiences from recent earthquakes, like the Great Hansin Awaji
Earthquake, clearly show that piers in bridges are relatively vulnerable toearthquake because it is suffered with very large inertial force. On the other
hand, some of the piers in chloride-attacked environment, such as marine
environment, have already deteriorated due to corrosion of thereinforcement. Particularly in the regions of high seismic risk, the behaviorof these deteriorated piers against earthquake becomes the matter of prime
concern. In addition, now the trend of repairing, renovating andrehabilitation is increasing rather than just demolishing and reconstruction.
Under such condition, it becomes necessary to evaluate the dynamic
behavior of the deteriorated bridge piers.
The main objective of this research is to evaluate the dynamic
properties such as, stiffness, ductility and energy absorption of the piers
deteriorated by corrosion of reinforcement. It is aimed to obtain the natureof degradation of these properties with increase in the loss of steel weight
due to corrosion of reinforcement. Moreover, the combined effect of theaxial load and the corrosion is also to be evaluated.
The purpose is also to study the behavior of the corroded piers against
the seismic loading, which were designed with two different ways. The firstone was designed by using the design method for ordinary structures in
JSCE code. The second one was designed with the seismic design part of
JSCE along with the verification of ductility.
2.0 OUTLINE OF EXPERIMENT
2.1 Test specimen

1401000 mm

1200 mm

The overall size of the specimen is shown in Figure 1. The height ofpier part was 1.2 meter, whereas the point of application of load was 1 meter
above the base. The specimen was designed for the axial load and themoment corresponding to the lateral load at the point of application of load.
In the design, lateral seismic load
220 mmwas assumed as 20 % of the axial
220 mmDucts for postload.
Using
the
strengthtensioning
Loadinteraction diagram, specimens
less than 200 kN of axial load
were designed with two design
Duct for anchor bolt
philosophies, which were design
methods specified by Japan
Society of Civil Engineer (JSCE)
500 mmcode for ordinary reinforced
concrete structures and by the1200 mm
320 mmseismic design part of JSCE codein conjunction with the Japan
Figure 1: Size of specimen
New Technologies for Urban Safety of Mega Cities in Asia
241

ICUS Report 6

Road Association (JRA)’s specification for the verification of ductility
against the seismic load. Figure 2 shows the detail of the specimen designedby both philosophies.
Mix proportion and the average strength of the concrete used wereshown in Table 1.

12.7 mm PC Tendons

4-D20
9 @80 mm9@200 mm
6-D 20

6-D20

9 @200 mm

9 @200 mm(a) Specimen with ordinary
design(b) Specimen with earthquake
resistant design

Figure 2: Detailing of the specimens
Size of specimen
Table 1: Mix proportion of concrete
Unit weights (kg/m3)

W/C
(%)

W

C

S

G

.55

192

349

828

935

Compressive
Strength(Mpa)
35

2.2 Experimental parameters and number of specimens
The main parameter that was considered in the experiment was degreeof corrosion of the reinforcement. The experiments were carried out for four
different degrees of corrosion including non-corrosion condition.
Another important parameter that was varied in the experiment was
the condition of axial load. Two sets of experiments were performed withand without axial force. The third important parameter was the designprinciple mentioned in 2.1. With all these combinations, the total specimen
number was sixteen. The designation and its corresponding conditions are asshown in Table 2.
2.3 Accelerated corrosion test of reinforcing bars
To simulate the deterioration of concrete structure due to rebar
corrosion in the laboratory in a short time, accelerated galvanic corrosion

Seismic Behavior of Reinforced Concrete Piers Deteriorated by Corrosion of Reinforcement
242

141

October 2004, Agra, India

technique has to be used. Specimens were cured for fourteen days before
accelerated corrosion test was performed. To have galvanic accelerated
corrosion, specimen was immersed into a tank with 3.5% sodium chloride
solution that
Table 2: Test specimens
No.

Designation

Expectedcorrosion(*)

Axial
load

Ordinary design
1

POA-1

2

POA-2

3

POA-3

4
5
6
7
8

POA-5
PON-1
PON-2
POA-3
PON-5

No.

Designation

Axial
load

Expectedcorrosion(*)

Seismic design
200
kN

0

0.00

9

PEA-1

0.19

10

PEA-2

0.38

11

PEA-3

0.56
0.00
0.19
0.38
0.56

12
13
14
15
16

PEA-5
PEN-1
PEN-2
PEN-3
PEN-5

0.00
200
kN

0

0.19
0.38
0.56
0.00
0.19
0.38
0.56

acts as an electrolyte. In this method, rebars of the specimen that had to becorroded was made anode and titanium mesh was used as cathode. The
schematic circuit diagram for the experiment is shown in Figure 2.
The weight loss in the rebars by this technique can be obtained byusing Faraday’s law. The relation is as follows;
w

AIt
ZFa

(1)

where, w : metal weight loss due to corrosion, A : atomic weight of iron
(56 g), I : corrosion current in ampere, t : time elapsed in sec., a : reinforceing bar surface area before corrosion, Z : valence of the reacting electrode(iron) which is 2, F : Faraday’s constant (96,500 amp sec), : constantdepending on the concrete quality and cover thickness
The value of
depends on the quality of Current
concrete and the cover supplierLongitudinal
thickness. This factor had
rebar (anode)
to be determined by the
3.5% NaCl+solution net
Titanium
preliminary tests. Poudel(cathode)(2001) had carried out
Testexperiments in the similarTankconditions for the case ofbeam and found the valueof to be 1. Therefore, theresult obtained from that Figure 2: Circuit diagram for accelerated
experiment was used as
corrosion test
preliminary test results.

142

New Technologies for Urban Safety of Mega Cities in Asia
243

ICUS Report 6

2.4 Experimental setup

3.0 RESULTS
3.1 Deterioration conditionof specimens

Displacement(mm)
Displacement (mm)The experiment was carried out with the experimental setup as
shown in Figure 3. Figure 4 shows the lateral loading cycle on thespecimens in terms of displacement. Design yield lateral loads were 33.1kN
and 36.3kN for the specimens with and without the axial load, respectively.
Therefore, in the first three cycles until 30kN of the lateral load, the loading
was controlled by load andthen it was changed to be in
Hydraulic Actuator
displacement
controlwith Force Sensor
condition; that was, theReactionDial
fourth cycle was started with
Frame
Gauge
the maximum displacement
12.7 mmTendonwas 16 mm and thenTestfollowed by the cycles inSpecimenwhichthemaximum
Anchor Bolt
displacement was increasedby 8 mm each. Consequently,
the order of the cycles was
15 kN, 21 kN, 30 kN,
LateralLoad History
Figure3:
Experimental
setup
16 mm, 24 mm, 32 mm,
150
40 mm and so on, until the100
specimen was collapsed.
50
0
0

4

8

12

16

-50
-100
-150

CycleCycle
numberNumberTypical deterioration
Figure 4: Lateral load history
conditions on the specimens
after accelerated corrosion test are shown in Figure 5 and Table 3. Corrosion
loss in rebars that were taken out from the specimens was measured after thelateral loading test. Though the average corrosion loss was smaller than the
expected ones calculated by using equation (1), all of the specimens
suffering corrosion of rebars had the corrosion cracks on the concretesurface along with the main rebar’s direction.
Figure 6 shows the relationship between corrosion loss in rebar andaverage corrosion crack width. In the lower degree of corrosion, the entire
specimen showed very close value in crack width with the same corrosion
loss, while in higher corrosion condition some difference arose. However,nearly the linear behavior was also observed in the relation between averagecrack width and corrosion loss.
3.2 Load-displacement curve
The typical load displacement curves of the specimens under theloading test are shown in Figure 7. The shape of the curve for specimens, inwhich the average corrosion loss in rebars was less than 0.20 and the

Seismic Behavior of Reinforced Concrete Piers Deteriorated by Corrosion of Reinforcement
244

143

October 2004, Agra, India

average corrosion cracks width was smaller than 0.5mm, was almost thesame and had relatively the large area enclosed by the hysteretic loop in the
all series

AverageCrack
crack
width
width
(mm) (mm)

0.2

0.2

0.2

1.4
1.4

0.4

0.9

0.3

0.4 0.3

1.2
1.2
1.0
1

0.3

0.4

0.8
0.8

0.2

0.6
0.6
0.4
0.4
0.2
0.2
00
00

0.1
0.1

0.2
0.3
0.4
0.2
0.3
0.4
2 2
Corrosion loss
loss (g/cm) )Corrosion
(g/cm

0.5
0.5

0.3

POA 2

PON
POA
PEN
PEA

0.6
0.6

POA 3

1.0

POA 4

0.3

0.3

0.3

0.4

0.4

0.3

0.4

0.6
1.3
0.9

0.2
0.3

0.4

Figure 6: Relationship between corrosion
loss in rebar and average crack
width on concrete surface

0.3

PEA 2

1.0

0.4 0.4

PEA 3

PEA 4

Figure 5: Typical corrosion
crack pattern with
its width

Table 3: Degree of deterioration and loading capacity of specimen
No.

Designation

Corrosion loss
(gm/cm2)
Expected

144

ActualDurationof test(days)

Crack width(mm)

Failure load (kN)Max.

Calculated

Avg.

Actual

58.66

1

POA-1

--

--

--

--

--

2

POA-2

0.19

0.04

6.6

0.3

0.23

3

POA-3

0.38

0.13

13.2

0.5

0.43

4

POA-4

0.56

0.47

19.7

1.3

0.72

46.71

5

PON-1

--

--

--

--

--

47.70

6

PON-2

0.19

0.05

6.6

0.4

0.26

7

PON-3

0.38

0.14

13.2

0.5

0.38

8

PON-4

0.56

0.52

19.7

2.0

1.15

30.00

9

PEA-1

--

--

--

--

--

61.31

10

PEA-2

0.19

0.17

6.6

0.6

0.38

11

PEA-3

0.38

0.22

13.2

0.9

0.47

12

PEA-4

0.56

0.53

19.7

1.3

0.91

13

PEA-1

--

--

--

--

--

48.95

14

PEN-2

0.19

0.06

6.6

0.50

0.31

48.87

15

PEN-3

0.38

0.12

13.2

0.50

0.35

16

PEN-4

0.56

0.31

19.7

1.60

0.63

55.21

42.07

55.21

54.25
54.59

44.30
44.20

60.18
54.05
51.84

42.07

48.87
33.01

New Technologies for Urban Safety of Mega Cities in Asia
245

ICUS Report 6

80
80
Load (kN)

8080

-80
-80

6

8

7

9

10

11

2020

2

4

-40
-40

-80
-80

-40
-40

0

-120

-80
-80

-60
-60

(b) PON 2

-80
-80

80
80

80
80

Load (kN)

Load (kN)

60
60

-40
-40

4
5

6

7

8

9

3
2

1

0
-20
-40
-40
-60
-60

9

40
80
120
40
120
Displacement (m m) 80
Displacement
(mm)

60
60
40
40

3

20
20

2
1

-120

8

-40
-40

(a) PON 1

0

7

1

-80
-80

20
20

6

10

20
20

-20

Cycle Number

-60
-60

40
40

5

3
2

0
-120
120 -12040
80
120Displacement (mm)4080Displacement (mm)-20

Load (kN)

60

40
40

1

00 0

-40
-40

5

3

Load (kN)

44040

Load (kN)

-120
-120

Load (kN)

Load (kN)

Figure 7 Example of load-displacement curve 60of specimens
6060

-120
40
80
120-120
Displacement (mm)4080
Dis placement (mm )

120

-80
-80

-40
-40

0
0
-20

4
5
6

7

8

40
80
120
80
40
120
Displacement (mm)Displacement (mm)

-40
-40

(c) PON 3

-80
-80

-60
-60

(d) PON 4-80-80

of PON, POA, PEN and PEA. In consideration of both the curve shapes andcrack development condition during loading, the specimens with axial load
(POA and PEA types) were seemed to be in the typical bending failure
nature, while the specimens without the axial load (PON and PEN types)
might be in a combination of bending and shear failure nature.
On the other hand, in the specimens having most severe corrosion
loss of rebars and the corrosion cracks with about 0.5mm or more of theiraverage width, the curve shows a typical bond failure condition with very
narrow loop area.
3.3 Strength

Strength ratio (%)

Strength of each specimen, which is explained as the maximum load
bearing capacity acting on the specimen during the cyclic loading test, isalso shown in Table 3. 120
Figure 8 shows the strength
ratio of the corroded 100
specimen to the non80
corroded one with corrosion
60
loss of rebars. With thesmall increase in degree of
40
PON
POA
corrosion within 0.05 g/cm2
PEN
20
the strength had shown only
PEA
10 % or less in reduction.
0
0
0.1
0.2
0.3
0.4
0.5
0.6
Then it remained stable withCorrosion loss (g/cm2)
only 5% more of strength
Figure 8: Trend of reduction in load bearing
reduction with some morecapacity of specimen withcorrosion loss around 0.15
corrosion loss
g/cm2. With further increasein corrosion loss, the strength started to reduce rapidly.

Seismic Behavior of Reinforced Concrete Piers Deteriorated by Corrosion of Reinforcement
246

145

October 2004, Agra, India

From the figure, it seems that the strength mainly depends on thedeterioration condition such as the corrosion loss and occurrence of thelongitudinal corrosion crack, regardless of design method and axial loadcondition. Therefore all the data can be fitted by an approximate curve asshown in Equation (2). With the known flexural strength of non-corrodedpier, the strength of the corroded pier may be predicted for the various
corrosion condition by this equation.
Pc(1

0 .1 7 0 3 w 2

0 .5 2 4 4(2)w ) Puwhere, Pc : strength of corroded specimen, Pu: strength of non-corroded
specimen, w: corrosion loss (g/cm2)
3.4 Ductility
Ductility of a structure is defined as the ratio of ultimate
displacement to the yield displacement. In this study, the ultimate
displacement was determined from the load displacement curve at the pointof collapse where the load bearing capacity has been reduced by 20 percent
from the strength of the specimen.
9

PON
POA
PEA
PEN

8
7
6

Ductility
Ductility

Figure 9 shows thedegradation of the ductility
with increase in corrosionloss.
It can be clearlyobserved that the ductility inthespecimens
without
corrosion was larger in thecase of specimens designedforseismic
resistance,
though there was not any

5
4
3
2
1
0
0

0.1

0.2

0.3

0.4

0.5

0.6

2

Corrosionloss
loss (gm/cm) 2)
Corrosion(gm/cmDuctility ratio (%)

significant
changeinductility due to axial load Figure 9: Relationship between ductility of
specimen and corrosion loss on
condition. The ductility isrebarsalso found to be very
susceptible to the corrosion 120
PON
of reinforcement. Especially,
POA
100
PEA
when the corrosion loss was
PEN
280
more than 0.15 gm/cm ,ductilitywas
reduced60
significantly and became less40
than 2 with corrosion loss
2
more than 0.4 gm/cm , which20
was around one third to one
0fourth of the ductility on the
0
0.1
0.2
0.3
0.4
0.5
0.6
Corrosion loss (g/cm )specimen without corrosion.
2

Figure 10: Trend of reduction in ductilityof specimen with corrosion loss

146

New Technologies for Urban Safety of Mega Cities in Asia
247

ICUS Report 6

Figure10 illustrates the trend of ductility reduction with increase incorrosion loss. The theoretical calculation considering the effects ofcorrosion on both main rebars and lateral ties showed that the rate of
reduction of ductility in the specimens with seismic design was higher than
the specimens with ordinary design under the same condition of corrosion
loss. However, for corrosion loss up to 0.5gm/cm2, the difference in the
reduction rate of ductility with corrosion loss was found to be small in the
all series. Therefore, for the simplicity in ductility estimation, the best fit
parabolic curve was evaluated from all the results, and ductility of corroded
specimen may be predicted by using Equation (3).
c

(1 1.149 w2 0.7927 w) u

where, c: ductility of corroded specimen,
specimen, w: corrosion loss (gm/cm2).

(3)
u:ductility of non-corroded

3.5 Energy absorption

En e rgy a b so rp tio n (k N -m m )Energy Absorption ( x104kN-mm)

Energy absorption was obtained by calculating the area under thehysteretic curve. Figure 11 shows the degradation of total energy absorptionof specimen with the60000
increase in corrosion loss.
PEA
PON
5
50000
The
total
energyPOA
PEN
absorption
of
the
40000
4
specimens with seismic
30000
3
design was much larger
2
20000
than the specimen withordinary design in the1
10000
case of non-corroded00
condition. However, it
0.1
0.2
0.3
0.4
0.5
0.6
00
0.1
0.2
0.3
0.4
0.5
00.6
Corrosion loss (gm /cm )was sharply decreased
Corrosion loss ( gm/cm2)
with increase in corrosion
on the specimens designed Figure 11: Relationship between energy
not only by the ordinary
absorption of specimen anddesign method but also bycorrosion loss on rebars
the seismic one.
120
2

PEA
PON
POA
PEN

Figure 12 shows theratio of energy absorption
80
of corroded specimen to60
that of non-corroded one.
40
Total energy absorption isvery sensitive to the20
corrosion of reinforcement.
0Consequently, in higher
0
0.1
0.2
0.3
0.4
0.5
Corrosion loss (g/cm )corrosion condition withcorrosion loss of 0.5 Figure 12: Trend of reduction in energy
gm/cm2 or more, theabsorption of specimen with
Energy absorption ratio (%)

100

2

0.6

corrosion loss
Seismic Behavior of Reinforced Concrete Piers Deteriorated by Corrosion of Reinforcement
248

147

October 2004, Agra, India

energy absorption dropped drastically down by 10% for non-corroded
specimen, regardless of the difference of design method. The trend of
reduction of energy absorption had a little effect of design condition. The
rate of the reduction was found to be larger in the specimens with seismic
design especially in the lower corrosion condition than about 0.3 g/cm2 ofcorrosion loss. However, the relationship between the rate of energy
absorption and the corrosion loss for the specimens designed by bothmethods were not much difference from each other. Consequently, theenergy absorption of the corroded specimen was explained as an equation
(4).
Ec

(4)

(1 1.8517 w) Eu

where, Ec: energy absorption of corroded specimen, Eu: energy absorptionof non-corroded specimen, w: corrosion loss (gm/cm2).
4.0 CONCLUSION
From the experimental results on the dynamic properties of the piers
deteriorated due corrosion of reinforcement, the following conclusions wereobtained:
Seismic performances of reinforced concrete structures such as
strength, ductility, stiffness and energy absorption are seriously
affected by corrosion of reinforcement.
With the increase in the corrosion loss of reinforcing bars,
reduction rate of ductility and energy absorption of the pier ismuch higher than that of strength. Therefore, even when only aslight reduction of strength of structure due to corrosion ofreinforcement has been observed from static loading test, it should
be considered that the corrosion is responsible for much larger
reduction of ductility and energy absorption. Corrosion ofreinforcement becomes much more critical parameter for thedeteriorated structures in earthquake action.
Reduction rate of strength, ductility and total energy absorption
with corrosion loss of reinforcement can be quantitatively
evaluated by experimental equations.
REFERENCES
Takewaka, K and Poudel, U. P., 2001. Bending Property of Reinforced HighStrength Concrete Structure Deteriorated by Corrosion of Steel
Reinforcement. Proceedings of the Third International Conference on
Concrete under Severe Conditions, Vol.2, CONSEC’01.
Takewaka, K. and Matsumoto, S., 1984. Influence of Corrosion of
Reinforcement on Mechanical Property of Reinforced Concrete Beams.
Proceedings of JCI, Vol. 6,Japan Concrete Institute.

148

New Technologies for Urban Safety of Mega Cities in Asia
249

SEISMIC PERFORMANCE OF POSTTENSIONED INTERIOR FLAT SLABCOLUMN CONNECTIONSPENNUNG WARNITCHAI1, SOMMAI PONGPORNSUP1,
UNNOP PRAWATWONG1 AND AMORN PIMANMAS2Asian Institute of Technology, Thailand
2
Sirindhorn International Institute of Technology, Thailand
pennung@ait.ac.th
ABSTRACTThis paper presents the results of reversed cyclic loading test of a 3/5
scale slab-column connection model, which was carefully designed andconstructed to represent a typical connection between interior column andpost-tensioned flat slab with bonded tendons in Thailand. A conventional
displacement-controlled cyclic loading test with monotonically increasing
drift levels until failure was adopted to investigate the seismic performanceof the connection. The lateral force-deformation relation indicated that foreach loading cycle the connection model essentially behaved like a linear
elastic system with low energy dissipation. As the drift level increased,cracks on the slab surface grew in size and number and concentrated
around the column, and the lateral stiffness of the model degradedsignificantly. Shortly after attaining its maximum lateral strength at 2%
drift, the specimen abruptly failed by punching shear. The drift at which thenon-ductile failure occurred is considered to be rather low, and hence
design improvement for slab-column connections is deemed desirable. The
test results on cyclic properties of the response, including stiffness
degradation, hysteretic shape, and failure mode, will be useful for theevaluation of seismic performance of the entire slab-column frame buildingsin the future.
1.0 BACKGROUND
Over the past three decades, rapid urbanization and massive scale ofbuilding construction have taken place in Bangkok and several major citiesin Thailand. As the country has long been considered as being free fromseismic risk, most existing buildings have been designed and constructedwithout any consideration on seismic loading. Recently, however, there has
been a significant improvement in the understanding of seismic risk. New
probabilistic seismic hazard studies indicate that northern and western
Thailand can be regarded as regions of moderate seismic hazard, and that
Bangkok, though located at a remote distance from seismic sources, is stillat risk from long-period, damaging ground motions induced by distant large
earthquakes (Warnitchai 2004). The risk in Bangkok is primarily caused by
the ability of thick soft surficial deposits in the city area to amplify
earthquake ground motions about 3 to 4 times.

147
250

October 2004, Agra, India

To mitigate the risk, seismic design requirements in the form of
mandatory ministerial regulations were introduced in 1997. The regulations
stipulate that public buildings, essential facilities, hazardous facilities, andall other buildings with height above 15 meters in 10 provinces in northern
and western Thailand must be designed for a moderate level of earthquake
ground shaking. A revision of the regulations is currently being made toinclude the design requirements against the effects of distant large
earthquakes for buildings in Bangkok and 4 neighboring provinces.
Despite the introduction of statutory seismic design requirements,
their actual implementation in design practices seems to have manydifficulties and limitations. Most design engineers are not familiar withseismic design concepts and procedures, and they normally do notunderstand the need for seismic detailing. Many engineers believe thatbuildings typically designed for gravity loads and wind load (but no seismic
detailing) do have sufficient inherent capacity to withstand the expectedmoderate earthquake ground shaking.
Under these circumstances, a research program on the seismic
performance of several typical buildings in Thailand is currently being
conducted by the authors. The main objectives are to: (1) determine theinherent seismic capacity of typical buildings of various forms; (2) identify
their typical weak spots, detailing deficiencies, and poorly performed
structural configurations; and (3) find out economic and practical ways toimprove the design of new buildings and to retrofit existing buildings. One
key element in this research program is a study on the performance of somecritical building components under reversed cyclic loading.
These
components include, for example, RC columns with short lap splices, beamcolumn joints with no joint reinforcement, and slab-column connections, etc.
In this paper, a study on the seismic performance of post-tensioned
interior flat slab-column connections is presented. A quasi-static, reversed
cyclic loading test of a 3/5 scale connection model was carried out, and its
behavior and failure mode were examined in detail. The results from thisstudy will be critical ingredients for the evaluation of seismic performanceof slab-column frame buildings in Thailand.
2.0 SLAB-COLUMN FRAME BUILDINGS IN THAILAND
Post-tensioned flat slab construction is popular in Thailand for
medium to high rise buildings such as office buildings, hospitals, residentialbuildings and parking buildings. A slab-column frame is normally designed
to carry only gravity loads, while the lateral wind load is assumed to betaken care of by concrete shear walls. The slab-column frame is neither
designed for lateral seismic load nor checked for lateral deformationcompatibility with shear walls to ensure that it can undergo the maximum
lateral drift (due to seismic load) without losing gravity load carrying
capacity.

148

New Technologies for Urban Safety of Mega Cities in Asia
251

ICUS Report 6

It is widely known that the slab-column connection is a criticalcomponent in the slab-column frame system. This is the region of slab
immediately adjacent to the column that has to transmit large torsion, shear
and bending moments between slab and column and is therefore susceptible
to punching shear failure. In Thailand, slab-column connections are
typically not designed and detailed for seismic effects. No shear
reinforcement (such as stirrups or stud-rails) is provided at slab-column
connections. Although slab bottom reinforcement bars are provided in an
orthogonal mesh to satisfy a minimum requirement for temperature andshrinkage effects, there may be no continuous bottom bar passing throughthe column to protect against progressive collapse after punching shear
failure. Furthermore, due to the congestion of reinforcement bars in thecolumn section, prestressing tendons are normally arranged such that noneof them passes through the column.
Despite the fact that a reasonably large number of research studies on
the behavior of slab-column connections under seismic loading have been
carried out in the past, most of them were made for reinforced concrete slabcolumn connections. Only a few focused on post-tensioned flat slab-column
connections (e.g. Hawkins 1981, Burns et al. 1985, Martinez-Cruzado et al.
1994, Kang et al. 2004), and none of them were made for ‘bonded’ posttensioning tendons system with non-seismic reinforcement detailing, whichis the prevailing type of flat slab construction in Thailand.
3.0 KEY STRUCTURAL INDICESAs the objective is to study the seismic performance of post-tensionedslab-column connections that are typical in Thailand, an effort was made toacquire architectural and structural drawings of five representative buildings
with post-tensioned floors in Bangkok. The number of stories of thesebuildings varies from 15 to 30. Some important structural parameters
associated with seismic behavior are computed from the drawings; they are
herein called ‘structural indices’. These indices are: gravity shear ratio( Vg / V0 ), critical section perimeter-to-depth ratio ( b0 / d ), side ratio ( b1 / b2 ),gravity shear-to-moment ratio ( e r Vg / Mg ), prestressing ratio ( f pc / f c ' ),negative moment reinforcement ratio (( Mg / Mn ).

s), and gravity moment ratio

In the above, Vg is the gravity shear acting on the slab critical section,
V0 is the direct punching shear strength as defined by ACI 318-95, b0 isperimeter of the critical section, d is the effective depth, b1 is the width ofthe critical section measured along the direction of loading, b2 is the otherdimension of the section orthogonal to b1, Mg is the negative moment at theslab-column connection caused by gravity load, er is the ratio of the shear
stress caused by a unit direct shear to the maximum shear stress caused by aunit unbalanced moment on the critical section, fpc is the compressive stressin concrete slab at the centroid of cross section due to prestressing force,s is the ratio of total area of top reinforcement bars to (c2 +3d).d, c2 is the

Seismic Performance of Post-Tensioned Interior Flat Slab-Column Connections
252

149

October 2004, Agra, India

column width measured orthogonal to the direction of loading, Mn is thenominal slab moment capacity. Note that the gravity load here is the deadload (without load factor) plus ‘likely live load’ of which the value is given
by ATC-40 (ATC 1996) based on the building occupancy type.
The indices’ values of interior slab-column connections in five
representative buildings are given in Table 1. The values do not vary muchfrom case to case, indicating the structural similarity between all these cases.
Among these indices, the gravity shear ratio ( Vg / V0 ) appears to be the mostimportant one, as many test results in the past indicate that the lateral drift
level at which a connection punching shear occurs is strongly influenced bythis index (Hueste et al., 1999). For gravity shear ratios higher than 0.4—
which is the maximum limit recommended by ACI 318-02, the drift
capacity could be unacceptably low, say below 1.5 % in some cases. Table
1 shows that the gravity shear ratio of every representative building falls
within the limit, with a moderately high average value of 0.289.
Table 1:
Building

Office 1
Office 2
Office 3
University
Hospital
AverageSpecimen*

Structural indices of interior slab-column connections in five
representative buildings and those of test specimen
Span

ColumnSize(cm)(cm x cm)

800
700
800
800
840
800
480

40x100
40x80
40x80
50x80
50x70
40x80
25x50

b1
b2

e r Vg

f pc

V0

b0
d

Mg

fc

0.267
0.296
0.287
0.231
0.366
0.289
0.280

21.5
19.0
19.0
18.8
18.3
19.3
18.3

2.07
1.71
1.71
1.44
1.30
1.65
1.70

1.72
1.67
1.21
1.40
1.52
1.50
3.25

Vg

*

0.84
1.01
0.84
1.04
0.87
0.92
0.93

s

Mg
Mn

'

0.014
0.011
0.010
0.008
0.009
0.010
0.011

0.13
0.11
0.16
0.11
0.15
0.13
0.07

unit = kg/cm2

4.0 TEST SPECIMEN AND EXPERIMENTAL SETUP
The test specimen is a 3/5 scale slab-column interior connection model
as shown in Figure 1. As the inflection points in the slab-column frame
system under seismic loading are assumed to occur at slab mid-span andcolumn mid-height, the model slab extends to mid-span on two sides of theconnection and the column extends above and below the slab to story midheight. The slab was supported along each transverse edge by 5 pin-ended
bars to simulate a moment-free boundary condition. Similarly, to produce
moment-free condition at the column ends, the column bottom end was set
on a hinged support, and the top end was connected to a hydraulic actuator
through a pivoted connection. The test specimen was designed to have thevalues of structural indices close to the average values of representativebuildings as shown in Table 1.

150

New Technologies for Urban Safety of Mega Cities in Asia
253

ICUS Report 6

500

5700
5700

500

Loading

250

Pivot

840

Pin-end bar
Hinge

840

2400
2400

120

160

2400
2400
5700
5700

5700
5700

(unit : mm)(a) Plan(b) Elevation

Figure 1: Interior slab-column connection specimen and its dimensions
The prestressing strands are grade 270, seven-wire, stress relieved typewith a nominal diameter of 12.7 mm. Eight strands were banded in the
direction of loading with a spacing of 350 mm. Other eight strands wereplaced uniformly in the direction perpendicular to the loading with a spacingof 700 mm as shown in Figure 2. Each strand was inserted into agalvanized duct to prevent bonding with concrete before prestressing. Threedays after casting slab, all these strands were tensioned one by one to about
80 % of their ultimate strength (0.80 fpu). Shortly afterward, all galvanizedducts were filled in by non-shrink cement grout.
Top slab reinforcement bars were placed symmetric about both
centerline axes as shown in Figure 3. The top bars were concentrated onlyat the slab-column connection region and have a spacing of 80 mm. Thesebars were cut off at a distance of 1.0 m from the center of the column.
Figure 3 also shows the layout of bottom slab reinforcement which issymmetric about both center line axes. The bottom bars were spaced at 550
mm intervals throughout the slab. Although the specified steel grade of all
slab reinforcement bars was SD-30, their tested yield and tensile strengths
were about 440 and 580 MPa, respectively. The average compressive
strength of concrete cylinders for slab at 4, 14, and 28 days were 20, 39, and
40 MPa, respectively.
Before applying a lateral reversed cyclic load, a large number of sandbags were piled up on and hanged underneath the slab as shown in Figure 4
in order to correctly simulate the gravity load effects. The amount anddistribution of sand bags were determined by a finite element analysis suchthat the computed gravity shear ratio was close to the average value ofrepresentative buildings. The lateral load was applied to the top column by
an MTS servo controlled hydraulic actuator mounted horizontally to a rigid
reaction wall (Figure 4).

Seismic Performance of Post-Tensioned Interior Flat Slab-Column Connections
254

151

October 2004, Agra, India

480

700

700

700

540

700

700

700

480

1655

350
350
350
290
350
350
350

1655

120
(unit : mm)

Figure 2: Layout of prestressing strands

Top bars
10 DB10 @ 80 mm
2000 mm

Top bars
8 DB10 @ 80 mm
2000 mm
Bottom bars
DB10 @ 550 mm #5600 mm

120(unit : mm)

Figure 3: Layout of top and bottom steel deformed bars
Note that this test setup was found to be rather weak in torsion, so a
torsional restraining system was attached to the test specimen. A typicaldisplacement-controlled cyclic loading test was then carried out withmonotonically increasing drift levels of ±0.25%, ±0.5%, ±0.75%, ±1.00%,±1.25%, ±1.50%, ±2.00%, …. For each drift level, two complete cyclic
displacement loops were made.

152

New Technologies for Urban Safety of Mega Cities in Asia
255

ICUS Report 6

Figure 4: Setup for reversed cyclic loading test
The data measured and recorded in the experiment include: (1) lateralforce and displacement at the top column end, (2) lateral displacement andrigid-body twisting angle of slab, (3) bending curvature of slab in front ofand behind the column, (4) strain in top and bottom bars of slab at various
locations, (5) strain distribution along some prestressing strands, and (6)strain of longitudinal bars of column. Photos were also taken at peak
positive and negative drifts in every cycle of loading to record thedevelopment of visible cracks on top slab surface in the connection region.
Full details of the test specimen instrumentation can be found in(Pongpornsup 2003).
5.0 EXPERIMENTAL RESULTS
Due to space limitation, only some results are presented here in thissection. First, the development of cracks on the top surface of the slabaround the column is shown in Figure 5. The first observable cracks werelongitudinal cracks running in the direction of loading and passing throughthe column sides. They initiated at the lateral drift of 0.25%. The
development of diagonal cracks radiated from column corners followed
afterward and became more obvious at 0.5% drift. These diagonal cracks
might be caused torsion in the slab, which was resulted from the differencein flexural deformation of slab strips near and far from the column faces.
The flexural deformation of the slab strip adjacent to the column face wasfound to be the highest. Transverse cracks were clearly developed at about
1.0% drift. As the drift level increased, these longitudinal, diagonal, andtransverse cracks widened and lengthened and grew in number around theconnection.

Seismic Performance of Post-Tensioned Interior Flat Slab-Column Connections
256

153

October 2004, Agra, India

While the slab was pushing toward the positive direction after
completing two cycles at 2.0% drift, a punching shear failure suddenly
occurred on one side of the connection at about 1.70% drift. After that, theslab was then pulling back toward the negative direction, and anotherpunching shear failure suddenly developed on the other side of theconnection at about -0.8% drift, thus forming a complete loop of punching
shear failure as shown in Figure 5. Note that the punching shear failure did
not occur at the critical section.

Figure 5: Development of cracks on the top surface of slab
The relation between lateral load and lateral drift is shown in Figure 6.
The hysteretic loop in every loading cycle before punching shear failure waslong and narrow, indicating a limited ability to dissipate energy. Neither
pinching behavior nor plastic residual deformations were observed. As thedrift level increased, the peak lateral load also increased, but the average
stiffness (secant stiffness) reduced. The test specimen essentially behaved
like a linear elastic system with significant stiffness degradation. The
stiffness degradation is believed to be caused by the extensive andprogressive cracking of slab in the connection region. Strains in slab bottom
bars, prestressing strands, and column longitudinal bars fluctuated within
the limit of linear elastic, while strains in slab top bars exceeded the yield
limit at about 1.5% drift. The maximum lateral load of 105 kN was attained
at 2.0% drift. After the punching shear failure occurred at around 2.0% drift,
the test specimen completely lost its lateral strength and stiffness.

154

New Technologies for Urban Safety of Mega Cities in Asia
257

ICUS Report 6

Compared with other test results on slab-column connections done
elsewhere (e.g. Hueste 1999), the drift of about 2.0% at which the punching
shear failure occurred appears to be rather low. Improvement in the designof post-tensioned slab-column connections is deemed desirable.
120

Lateral force (kN)

80
Punching
shear
failure40
Punching shear
failure

0

-40

-80

-120
-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

Story drift (%)

Figure 6: Relation between lateral load and lateral drift
6.0 CONCLUSIONS
A 3/5 scale model was designed and constructed to represent a typicalconnection between interior column and post-tensioned flat slab in medium
to high rise buildings in Thailand. The model was tested under aconventional reversed cyclic loading with monotonically increasing drift
levels until failure to investigate its seismic performance. During the test,
the specimen essentially behaved like a linear elastic system with low
energy dissipation, as indicated by its long and narrow hysteretic loops. As
the drift level increased, cracks on the slab surface around the column grewin size and number, and the lateral stiffness of the specimen degradedsignificantly. Shortly after attaining its maximum lateral strength at 2%
drift, the specimen abruptly failed by punching shear. The drift at which thenon-ductile failure occurred is considered to be rather low, and hence design
improvement for slab-column connections is deemed desirable. The test
results on cyclic properties of the response, including stiffness degradation,hysteretic shape, and failure mode, will undoubtedly be useful for theevaluation of seismic performance of the entire slab-column frame buildingsin the future.

Seismic Performance of Post-Tensioned Interior Flat Slab-Column Connections
258

155

October 2004, Agra, India

ACKNOWLEDGEMENTS
This research work was funded by the EDM EqTAP Project of the
National Research Institute for Earth Science and Disaster Prevention
NIED of Japan and also by the Thailand Research Fund TRF We wish to
express our sincere appreciation to both organizations for providing theopportunity to undertake this research work
REFERENCES
ATC, 1996. Seismic evaluation and retrofit of concrete buildings. Volume 1,
ATC- 40 Report, Applied Technology Council, Redwood City,
California.
Burns, N.H. and Roongroj, Hemakom, 1985. Test of post-tensioned flat
plate with banded tendons. Journal of the Structural Division, ASCE,
Vol. 111, No. 9, 1899-1915.
Hawkins, N. M., 1981. Lateral load resistance of unbonded post-tensioned
flat plate construction. PCI Journal, Vol. 26, No.1, 94-116.
Hueste, M. B. D., Wight, J. K., 1999. Nonlinear punching shear failure
model for interior slab-column connections. Journal of StructuralEngineering, Vol. 125, No. 9, 997-1008.
Kang, T. H. K., Wallace, J. W., 2004. Shake table tests of reinforced
concrete flat plate frames and post-tensioned flat plate frames. Proc.
13th World Conference on Earthquake Engineering, International
Association for Earthquake Engineering, Vancouver, Canada, Paper No.
1119.
Martinez-Cruzado, J. A., Qaisrani, A.N., and Moehle, J. P., 1994. Posttensioned flat-plate slab-column connections subjected to earthquake
loading. Proc. 5th U.S. National Conference on Earthquake Engineering,Vol. 2, Earthquake Engineering Research Inst., Oakland, California,
139-148.
Pongpornsup, S., 2003. Seismic performance of post-tensioned interior flatslab-column connections. M. Eng Thesis, Thesis No. ST.–03-18, Asian
Institute of Technology.
Warnitchai, P., 2004. Development of seismic design requirements forbuildings in Bangkok against the effects of distant large earthquakes.
Proc. 13th World Conference on Earthquake Engineering, International
Association for Earthquake Engineering, Vancouver, Canada, Paper No.
744.

156

New Technologies for Urban Safety of Mega Cities in Asia
259

EQUIVALENT STATIC ANALYSIS AS PER
IS 1893:2002 – A SIMPLESOFTWARE TOOL
N. CHANDRA SEKHAR1, K. B. S. SUNIL BABU1
AND PRADEEP KUMAR RAMANCHARLA2
1
M.Tech (CASE) and2Assistant Professor & Coordinator,
Earthquake Engineering Research Centre, IIIT Hyderabad, India.
ramancharla@iiit.net
ABSTRACTThis paper presents a software tool for performing the static anddynamic analysis of regular and simple multi-storied structures. This
analysis procedure is based on IS 1893:2002 (Part I), Criteria for
Earthquake Resistant Design of Structures. This tool is a windows based
software program developed in Visual Basic. The tool provides a userfriendly GUI for the calculation of base shear and its distribution over theheight of the structure, depending on the input parameters. Usual input
parameters are structural dimensions, type of structure, soil type, purposeof structure and location. Though this tool is simple, can be used forverification of design within short time. This tool is aimed to help students,
architects and engineers during design of earthquake resistant structures.
1.0 INTRODUCTION
Earthquake engineering education in India though started early, it has
not picked up to the extent what is required at present. This is clearly
evident from the damages during previous earthquakes. Recent earthquake
in Bhuj, Gujarat on 26th Jan 2001 has also stressed the need for increasing
the awareness about earthquakes among the professional involved inconstruction activity. To address this issue, Ministry of Human Resources
Development, Govt. of India, (MHRD) initiated a programme called
National Programme on Earthquake Engineering Education (NPEEE) 1).
Under this programme, a large number of teachers from engineeringcolleges, architecture colleges and polytechnics are trained in the subject ofearthquake engineering. It is also felt that there is a need to develop
teaching aids and printed resource material relevant to India in this field. In
this connection, we plan to develop simple software tools that will help
students, professionals, and faculty members in understanding, teaching thebasics of earthquake resistant design of structures. As a preliminary attempt,
this tool is developed. Provisions of IS 1893 2002 are used in this tool for
performing equivalent static analysis and dynamic analysis of a simple
structure. The program has been adequately validated and found to provide
satisfactory results under all possible cases. This tool provides fast analysis
of simple structures.

21
260

October 2004, Agra, India

2.0 BRIEF OVERVIEW ON PROVISIONS OF IS 1893: 2002
Earthquake motion causes vibration of the structure leading to inertia
forces. Thus a structure must be able to safely transmit the horizontal andthe vertical inertia forces generated in the super structure through thefoundation to the ground. Hence, for most of the ordinary structures,
earthquake-resistant design requires ensuring that the structure has adequate
lateral load carrying capacity. Seismic codes will guide a designer to safely
design the structure for its intended purpose.
Seismic codes are unique to a particular region or country. In India, IS
1893 is the main code that provides outline for calculating seismic designforce. This force depends on the mass and seismic coefficient of thestructure and the latter in turn depends on properties like seismic zone inwhich structure lies, importance of the structure, its stiffness, the soil on
which it rests, and its ductility. Part I of IS 1893:2002 (here after we refer itas the code) deals with assessment of seismic loads on various structuresand buildings. Whole the code centres on the calculation of base shear andits distribution over height. Depending on the height of the structure andzone to which it belongs, type of analysis i.e., static analysis or dynamic
analysis is performed.
2.1 Static analysis
2.1.1 Calculation of design horizontal seismic coefficient
The total design seismic base shear (VB along any principal direction
shall be determined by following expression.
VB  Ah * W(1)where, W is the total weight of the building calculated using the structuraldetails and Ah is calculated as shown below:
Z  I  S 
Ah    *   *  a 
 2   R  g (2)where, Z is zone factor, I is Importance factor, R is response
reduction factor and Sa/g is spectral acceleration coefficient.
2.1.2 Design lateral force at each floor i
The design lateral force, Vb shall be distributed along the height ofthe building using equation 3.
Qi 

VB * Wi * hin

W * h
j 1

j

2

2
j

(3)

where, Q i = Design lateral force at floor i

22

New Technologies for Urban Safety of Mega Cities in Asia
261

ICUS Report 6

W i = Seismic weight of floor i
h i = Height of floor I measured from base andn = Number of storeys in the building
2.2 Dynamic analysis
Dynamic analysis shall be performed to obtain the design seismic
forces, and its distribution to different levels along the height of the building
and to the various lateral load resisting elements under any of the following
conditions:

For regular buildings, if the height is greater than 40 m in Zones
IV and V or greater than 90 m in Zone II and III
For irregular buildings, if height is more than 12 m in Zones IV
and V and more than 40 m in Zones II and III.

Dynamic analysis can be performed either by time history method or
response spectrum method. In this paper, response spectrum method is
discussed.
The peak response of the structure is calculated from the modal
combination, where the following two methods can be used
Square root of sum of squares (SRSS) method
r





2

k

(4)

k 1

Where k = absolute value of quantity in mode k, andr = number of modes being consideredComplete Quadratic Combination (CQC) method



r

r

   i 1 j 1

i

ij

j

(5)

where r = number of modes being consideredi = response quantity in mode i (including sign)

j

 ij

= response quantity in mode j (including sign)= cross-modal coefficientEquivalent Static Analysis as per IS: 1893-2002-A simple Software tool262

23

October 2004, Agra, India

8 2 1    1.5

1     4  1   
2 2

2

2

Where  = modal damping ratio

 = frequency ratio =  j  i
 i = circular frequency in i th modejth

= circular frequency in j mode

3.0 GUI OF THE TOOL
The user interface of the tool is shown in figure 3.1. It requires user toprovide certain input parameters such as location, type of soil, purpose ofbuilding, type of structure and dimensions of the structure.

Figure 3.1: The interface of the tool24

New Technologies for Urban Safety of Mega Cities in Asia
263

ICUS Report 6

Figure 3.2: Selection of different options from drop down menu

Figure 3 3: Selection of brick infill option

Equivalent Static Analysis as per IS: 1893-2002-A simple Software tool
264

25

October 2004, Agra, India

Based on the past seismic activity, India is divided into four zones.
Each zone is assigned one zone factor and for ready reference zone factors
for some important towns are mentioned in Annex E of the code. All thesecity names and assigned zone factors are stored in a database and can be
retrieved after selecting the city name from the drop down menu in the userinterface. Similarly, the other parameters like soil type, type of structure andpurpose of building are stored in the database. Selection of soil type decides
which curve to be used in figure 2 of the code, type of structure decides
what should be the value of response reduction factor and purpose ofbuilding retrieve the importance factor to be used in the analysis. Anotherparameter that helps us in selecting the formula for calculating fundamental
natural period is option that selects the structure with or without brick infill.
Basic theory includes the idealization of whole structure into a lumped
mass at each floor level. The tool will take all the input values mentioned
above and calculate the weights, lateral forces, time periods, frequencies ofeach floor and mode shapes. Finally the maximum response of the structure
is calculated using SRSS or CQC method depending on the natural
frequencies.
4.0 EXAMPLE PROBLEM
For testing the correctness of the developed software tool, we are comparing
the results of analysis of a simple 3-storied structured shown in figure 4.1.
First, analysis by hand calculation is performed and later results arecompared with software analysis results.
Given structure: 3-storeyed building
Location: Hyderabad (Zone II)
Soil type: Medium soil
Purpose: Residential
Structure type: Ordinary moment
resisting frame with brick
infillStorey height : 3m
Column dimensions: 230 mm x 230 mm
Beam dimensions: 230 mm x 230
mm
Slab dimensions
6mx6m
Number of columns:
9
Number of beams:
6
Unit weight of concrete: 25 kN/m3
Unit weight of brick : 18 kN/m3
Live load is 2 kN/m2
4.1 Analysis by hand calculation

3m

3m

3m

6m
6m

Figure 4.1: Example problem

Slab weight = (25 * 6 * 6 * 0.12) = 108 kN
Beam weight = (25 * 0.23 * 6* 6) = 47.61 kN

26

New Technologies for Urban Safety of Mega Cities in Asia
265

ICUS Report 6

Column weight:
First floor = (25 * 0.23 * 0.23 * 3 * 9) = 35.7 kN
Second floor= (25 * 0.23 * 0.23 * 3 * 9) = 35.7 kN
Third floor = (25 * 0.23 * 0.23 *1.5 * 9) = 17.8 kN
Wall weight:
First floor = (18 * 0.23 * 6*3*6) = 447.12 kN
Second floor = (18 * 0.23 * 6*3*6) = 447.12 kN
Third floor = (18 * 0.23 * 6*1.5*6) = 223.56 kN
Live load = (2 * 6 * 6) = 72 kN
First floor weight = 108+47.61+35.7 + 447.12+(0.2*72) = 652.83 kN
Second floor weight = 108+47.61+35.7+447.12+(0.2*72) = 652.83 kN
Third floor height = 108+47.61+17.85 + 223.56+(0.2*72) = 411.42 kN
Total weight (W)= 652.83+652.87+411.42 = 1717.094 kN
Fundamental natural time period for brick infil panel:Ta 

0.09 * hd=0.33 sec

Z=0.1, I=1, R=3, Sa/g = 2.5 (depends on Ta and type of soil)
Ah = 0.0416 from equation (2)VB = 71.43kN from equation (1)Distribution of seismic force to each floor: From equation (3)Q1 = 6.69 kN (for first floor)
Q2 = 26.77 kN (for second floor)
Q3 = 37.96 kN (for third floor)

In addition to static analysis, we performed dynamic analysis also;
Stiffness of each floor:
1st floor stiffness = 20858.116 kN/m
2nd floor stiffness = 20858.116 kN/m
3rd floor stiffness = 20858.116 kN/m
Mass matrix
652.837000652.837 000 411.420

Equivalent Static Analysis as per IS: 1893-2002-A simple Software tool266

27

October 2004, Agra, India

Stiffness matrix
41716-208580-2085841716-20858

0
20858
20858

Solving |K-M| = 0, frequencies (rad/second) are
1= 2.80, 2= 7.67 and 3= 10.57 and mode shapes for 1, 2, 3 are
1
0.481
0.845
1.000

2
-1.025-0.161
1.000

3
0.804
-1.2041.000

Since natural frequencies are distinct, SRSS method of modal combination
can be used. In such case, maximum displacement response of the structureis 0.357 m.
4.2 Analysis using software tool
After having performed the analysis by hand calculation, we will now do thesame using software tool. In this tool, it is required to input the parameters
by selecting options using the drop down menu as shown in figure 3.1.
Step 1:In GUI, select city for deciding zone factor, select the purpose of building
for deciding importance factor, select structural framework for deciding
response reduction factor and select soil type for choosing the curve fromtable 2 of the code to read spectral acceleration.
Step 2:Since the example problem is with brick infill, we have to input all physicaldimensions of the structure including wall and base dimensions.
Step 3:After entering all the dimensions, click on the ‘RUN’ button. Then, baseshear and its distribution as shown below will be displayed on the screen.
Base shear is 71.43 kN
Q1 = 6.69 kN (for first floor)
Q2 = 26.77 kN (for second floor)
Q3 = 37.96 kN (for third floor)

In addition to these, natural frequencies, mode shapes and maximum
displacement responses will be displayed. All these values are matchingwell with the results of hand calculations

28

New Technologies for Urban Safety of Mega Cities in Asia
267

ICUS Report 6

5.0 CONCLUSION
This paper discusses the simple software tool for performing equivalentstatic analysis of structures as per IS 1893: 2002 (Part I). For this purpose a
simple VB GUI has been developed in order to make the calculations simple.
This can be a handy tool for the civil engineers who wish to do structural
calculations in least time.
REFERENCES
Project Implementation Plan: National Programme on Earthquake
Engineering Education. A Ministry of HRD Initiative, Governmentof India, March 2003.
Indian standard Criteria for earthquake resistant design of structures,
Part1: General Provisions and Buildings, IS 1893(part1): 2002.
Bureau of Indian standards, New Delhi.
Evangelos Petroutrsos, 2002. Mastering Visual Basic 6.0. B.P.B. Publishers,
New Delhi.

Equivalent Static Analysis as per IS: 1893-2002-A simple Software tool
268

29



INTRODUCTION TO JSCE STANDARD
SPECIFICATION FOR CONCRETESTRUCTURESTAKETO UOMOTO
ICUS, IISc, University of Tokyo, Japanuomoto@iis.u-tokyo.ac.jp
ABSTRACTJapan has been constructing a large quantity of concrete structures
since 1950. In case of concrete structures, JSCE standard specification has
played an important role in the field of civil engineering, and most of thecivil structures in Japan are designed and constructed in accordance withthese specifications. Now, not only the materials of construction but also thedesign and construction methods, procedures inspection and maintenancehave also changed drastically since the specification was published in 1914.
JSCE has endeavoured to incorporate the latest development in the area of
research by suitably modifying the specifications. A change in the design
philosophy from the allowable stress to limit state design and now to a
performance based design concept, is only one example of these changes.
This paper provides a brief historical background to JSCE specifications
and an insight into the latest edition, where the performance and durability
based design and maintenance has been introduced for the first time.
1.0 INTRODUCTION
Since the end of 19th century, Japan has been constructing a large
quantity of structures introducing European and American methods,
modifying the method a little by little acceptable to Japanese culture. At the
beginning of 20th century, many new materials and design and construction
methods were introduced - such as to construction of structures using steel,bricks, plain and reinforced concrete. The first cement plant was setup by
the government in 1875 and handed over to a private company in the 1884,
which marked the beginning of cement production in Japan.
In 1923, the great Kanto earthquake shook the metropolitan area,
destroying numerous structures made of bricks and, and the ensuing fireburnt down wooden structures after the earthquake. This experience showed
the weakness of brick structures without enough reinforcement, andengineers decided to construct important civil structures using either steel orconcrete.
For large sale construction of these structures it was necessary forthe engineers to standardize the material to be used and the design andconstruction methods. Considering these, Concrete Committee of Japan
Society of Civil Engineers (JSCE) began publishing Standard Specifications
for concrete structures with the help of academicians, public officers,

13269

October 2004, Agra, Indiaresearchers and engineers from consulting and construction companies.
These standard specifications which have been published since 1931 haveplayed a leading role in the field of civil engineering, and most of the civil
structures in Japan are designed and constructed in accordance with them.
Modifications have been introduced in these specification from time
to time to incorporate findings from on going research and development,
and development in materials and construction technology. As an example,
the design philosophy for concrete structures was ‘allowable stress’, which
was changed to limit state design in 1986 to meet the requirements of safety
and economy. The concept has undergone a further revision, andperformance based design was introduced in 2002 to allow the use of many
newly developed materials and methods of design considering performances
other than strength: safety, aesthetics, durability, hazards to the public,
environmental issues, etc.
This paper provides a brief historical background to JSCE
specifications and an insight into the latest edition, where the performanceand durability based design and maintenance has been introduced for the
first time. The titles of chapters in some of the latest specifications are listed
in the Appendix for ready reference.
2.0 BRIEF HISTORY OF JSCE STANDARD SPECIFICATIONAs shown in Figure 1, the first Standard Specification of Concrete
Structure was published in 1931, and dealt with the design and constructionof reinforced concrete structures including bridges and other facilities. The
specification for non-reinforced concrete was published in 1943 to meet therequirements of construction of tunnels, concrete dams and other facilities.

After 1986

Maintenance
S.S. for Concrete for Dam

Concrete for Dam

S.S. for Concrete for Pavement

Concrete for Pavement

S.S. forConcrete

Test Methods and Specifications
Materials and Construction
Structural Design
Seismic Design

Recommendations
for PrestressedConcrete

Prestressed Concrete
Non-Reinforced Concrete

S.S for Prestressed
Cpncrete
S.S for Reinforced and
Non-Reinforced Concrete

S.S. for Non-Reinforced Concrete

Reinforced Concrete

S.S for Reinforced Concrete

1920

1940

1960

1980

2000

2020

Figure 1: Publication of the Standard Specifications of JSCE

14

New Technologies for Urban Safety of Mega Cities in Asia
270

ICUS Report 6

Considering the importance and the differences of concrete to be
used in dams and pavements, new specifications were published for dams
and pavements in 1949. After the Second World War, power generation andtransportation were the most urgent needs of the nation, and civil engineers
were involved in construction of concrete dams and roads across the country.
To prepare for the 1964 Tokyo Olympic Games the nation had toprepare not only stadiums but also highways and ultra-rapid trainsconnecting Tokyo and Osaka. Although Japan has large number ofearthquakes all year around, prestressed concrete was introduced in theconstruction of longer span bridges. In 1955, recommendation forprestressed concrete was published and after years of discussions, standard
specifications for prestressed concrete were published in 1978.
In 1986, all the specifications were combined into a single set called“Standard Specifications for Concrete” and individual specifications(volumes) became a part of these - design, construction, etc.. In this year,
limit state design was introduced for the first time, though an option to use
the allowable stress method was still retained, depending upon therequirements and wishes of a client.
In the 21st century, there was a pressure from both – clients and thesociety to use waste materials, reduce energy consumption, keep theenvironment clean, etc. To deal with the problem, performance based
specification was introduced in the 2002 edition of the Specifications,containing durability design. A new volume titled “Maintenance” was added
to the specifications to specially take care of the issues related to alreadyexisting structures. Learning from the disasters of the Great Hanshin Awaji
Earthquake (1995), more emphasis was placed on seismic design, which
was published as an independent volume separated from the volume ofdesign. Salient features of the durability design and maintenance volumes
are briefly discussed in the following sections.
3.0 EXAMPLES OF THE CHANGES
Figure 2 shows the changes of the maximum design strength of
concrete in the specifications. As can be seen, this value has been increasing
since 1931, and has now reached 1000kg/cm2 (since 1986), which ispractically six times that in 1931. The increase in more pronounced with theintroduction of prestressed concrete. This increase in strength of concrete
has become possible by improved methods of cement production, better
understanding of hydration processes and proportioning of concrete mixes,
better methods of production of concrete, and quality control.
However, this dramatic increase in design strength does not imply
that all structures are built with such ‘high strength concrete’, but simply
that the option is available for the use of such concrete, and the issues
related to design and construction using such material have been resolved atleast to the extent that allows their actual use.

Introduction to JSCE Standard Specification for Concrete Structures271

15

October 2004, Agra, India



1200

Maximum Design Strength (kg/cm2)

RC

1000

PC

1000
800
800

600

500
400

400

400

200

240
160

0
1940

1950

1960

1970

1980

1990

2000

2010

Figure 2: Changes in maximum design strength of concrete
Figure 3 shows the change of maximum water cement ratio whenfreeze thaw durability needs to be considered, and this change has beenpossible due to changes of material quality. In fact, presently, the maximum
water cement ratio of concrete is restricted by other factors, such as strength,
durability against corrosion etc.
65
Under Water

SplashNormal60

60
Water Cement Ratio (%)

55

55
50

55

53
49

45
45

40
35
(Note) Excluding marine concrete

30
1940

1950

1960

1970

1980

1990

2000

2010

Figure 3: Changes in maximum water-cement ratio of air entrained
concretes considering freeze-thaw durability
4.0 NEW STANDARD SPECIFICATIONS OF JSCEThe Concrete Committee of JSCE, the leading committee in the fieldof concrete, published revised editions of the Standard Specifications forConcrete Structures in 2000, 2001 and 2002 to address problems related to
durability and maintenance, which were becoming difficult to handle in theearlier specifications. The following two proposals can be considered themost important of the changes proposed in these documents:


16

Proposal for a new method for design and construction of new
concrete structures, wherein the structures can be used for a
specified lifetime at low cost of maintenance

New Technologies for Urban Safety of Mega Cities in Asia
272

ICUS Report 6

Proposal for an effective, economic and rational system for
maintenance of existing concrete structures, with minimum
investment in manpower. This aspect is important not only from thetechnical point of view but also considering the overall manpower
available for carrying out such jobs.

Addressing the above, the following two volumes have been
published – The Standard Specification for Construction Works of Concrete
Structures, (Jan. 2000), and, The Standard Specification for Maintenance ofConcrete Structures (Jan. 2001).
4.1 Durability design of new concrete structures [4]Performance-based durability design was introduced in the“Standard Specification of Concrete Structures” by the Concrete Committeeof JSCE in 2000. Although durability of concrete structures was considered
important in the previous specifications, performance-based design method
was not used. The previous specifications described the importance of
durability by proposing that the concrete structures are durable for a longtime when specified materials, mixes, covers, etc. are used. But these
specifications did not account for the time, in an explicit manner.
The proposed performance-based new durability design can besummarized requires that the concrete structure should be quantitatively
checked whether the structure possesses required performance over theentire designed period. Thus, the degree of deterioration of the structure inservice on account of a specific cause (mechanism) needs to be specified.
Also, to ensure that performance of a structure remains above the specified
degree of deterioration, the required performance also, needs to be specified.
To examine the performance on durability, a scheme similar to thelimit state design scheme was introduced, and the required equation can be
written as follows: i  Ad A  1.0
lim
where, Ad and Alim are the designed performance of the structure at
specified time considering the specified deterioration cause, and the limit of
the performance of the structure, respectively, and i is a coefficient to take
into account the importance, etc. of the structure.
Generally, the following deterioration items need to be examined,though sometimes, others such as fatigue loading, may also be examined.
 Corrosion of steel bars due to carbonation of concrete Corrosion of steel bars due to chloride penetration into concrete Deterioration of concrete due to freezing and thawing
 Deterioration of concrete due to chemical attack
 Deterioration of concrete due to alkali-aggregate reaction Water-tightness of concrete Deterioration of concrete due to fire

Introduction to JSCE Standard Specification for Concrete Structures273

17

October 2004, Agra, India

Concrete cover thickness (cm)

88
7

OPC

普通ポルトランドセメント

Service time
( Years )

66

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

5

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）

Dry Environment

1

00
40
40

45

50
50

55

60
60

Concrete cover thickness (cm)Figure 4 shows an example of the calculated result for minimum
cover thickness to prevent carbonation induced corrosion at different design
service lives for concretes with ordinary Portland and blast furnace slag
cements. As shown in the figures, the required cover thickness and watercement ratio changes substantially, depending upon the type of cement used,the environment (dry or wet) around the structure.
88

66

75
75年
5

Water
cement（％）
ratio (%)
水セメント比

70
70

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
65

Service time
(Years)100
100年

高炉セメントＢ種（スラグ40％）
Blast
Furnace
Slag Cement

7

Dry environment
40
40

50
50

45

55

60
60

65

70
70

Water
cementratio (%)
水セメント比（％）

Figure 4: Concrete cover and water-cement ratio for concrete made using
Ordinary Portland and Blast Furnace Slag cement
4.2 Methods of maintenance of existing structures [6])The methods used in the new Standard Specification are basically thesame as the conventional method. The difference is that the new method
requires maintaining the structure within their required performances
throughout their service lives, using the following basic principles: To maintain a structure, performances required for the structure must
be clearly defined, The performance(s) required for general structures are “safety”,“serviceability”, “hazards to the public”, “aesthetics and landscape”
and “durability” (See Figure 5).
 Structures must be maintained according to the designatedmaintenance category by formulating an appropriate maintenanceprogram to retain the performances within the specified tolerances
throughout their service life. The system for maintenance includes
adequate “initial inspection”, “deterioration prediction”, “inspection”,“assessment/judgment”, “remedial measures”, and “record” (SeeFigure 6).
As mentioned in items (1) and (2), Figure 5 shows the classificationof required performances of a general structure. Compared to otherperformances, “durability” performance is to keep the structure within
their tolerances throughout their lives.

18

New Technologies for Urban Safety of Mega Cities in Asia
274

ICUS Report 6

Load bearing including
Seismic performance

SafetyOther safety performancesServiceability performancesServiceability
Functionality performances
Required
Performancesof a structure

Hazards to public
Performance related to safety

Aesthetics

Performance related toserviceability

Durability

Serviceability related toHazards to publicServiceability related to aesthetics

Figure 5: Classification of required performance(s) of a structure [6]Also, considering item (3), Figure 6 shows how the maintenance
operation should be carried out. The details are highlighted below.
 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 “initialinspection”,“deterioration
prediction”,“inspection”,“assessment/judgment”, “remedial action”, and “record”.
 To maintain a structure, in addition to assessment and evaluation at
the time of inspection, assessment and evaluation should be carriedout throughout the service life based on prediction of deterioration.
 To predict the deterioration, required performances of the structure,and the design service life must be clearly defined and stated Records for design, construction, initial inspection, deterioration
prediction, periodical inspection, assessment and/or evaluation, andremedial actions must be kept throughout the service life.
Structure
Selection of
Maintenance Category

Determination of
Maintenance Category
Prediction of Deterioration
No Action
Assessment/
Judgement

Inspection

Need Action

Large-scale Remedial Action

Initial Inspection

RecordRemedial Action

Figure 6: Flowchart for maintenance of concrete structures [6]Introduction to JSCE Standard Specification for Concrete Structures
275

19

October 2004, Agra, India
One of the difficulties in the maintenance operation is prediction ofdegree of deterioration at the end of their service lives. Several efforts havebeen made to quantify deterioration [5,6]. In the published Standards,
several quantitative prediction methods have been cited as references forstructures suffering cyclic fatigue loads, carbonation induced corrosion andchloride induced corrosion. Whereas in case of cyclic fatigue, S-N curves
are used to predict the service life, in the case of carbonation and chloride
induced corrosion of steel bars, diffusion equations for carbon dioxide andchloride are used to predict the degree of corrosion. Using these methods, anestimate of the degree of deterioration can be made. But for other
deterioration problems, for whom a quantitative model is presently notavailable, a qualitative method “Grading method” has been suggested, and it
is hoped that research effort in the future in these areas will enable
development of appropriate tools.
The commonly used grading of apparent defects related to theprogress of deterioration is to classify the deterioration stages to “initiation”,“propagation”, “acceleration”, and “deterioration” stages. From the resultsof detailed inspection, the degree of deterioration can be estimated as shownin Figure 7. This is an example of corrosion induced deterioration. As canbe seen from the figure, initiation of corrosion takes place some years after
the structure is in service. Even when corrosion starts, it is difficult to
inspect whether corrosion has already started or not by visible inspections.
When corrosion proceeds to certain amount, cracks on concrete may appear
due to expansion of corroded steel bars. This shows that when cracks areobserved on concrete, it is already in the stage of propagation.
Degree ofDeterioration

Initiation of Corrosion
Cracking of
concrete due tocorrosionYears inservice
InitialStage

Propagation
Stage

Deterioration
Acceleration

Stage

Reduction of
Performance

Stage

Figure 7: Estimation of deterioration degree by grading method [6]5.0 CONCLUDING REMARKS
Engineering is not always complete, and further research works areneeded. To sustain existing structures, durability of the structure isimportant. One good method is to construct durable structures, but for the
existing structures maintenance is the only way to deal with the problem.
Although concrete committee of JSCE has set up a good system for
maintenance of existing concrete structures, there are still many things to bedone: not only researches but also education to the students and engineers

20

New Technologies for Urban Safety of Mega Cities in Asia
276

ICUS Report 6

about durability and maintenance. I hope this paper may become a help tothe concrete engineers of the world who are trying to design, construct andmaintain concrete structures.
ACKNOWLEDGMENT
The author would like to send sincere thanks to Dr. Sudhir Misra(IIT, Kanpur, India) and the members of Concrete Committee of JSCE
(Chairman: Prof. Kyuichi Maruyama) allowing me to explain some of theoutputs of the committee works related to the Standard Specification ofConcrete Structures. English version of the specification is now beingtranslated by the Translation Committee (Chairman: Dr. T. Ueda) and will
be published by March 2005.
REFERENCES[1] Uomoto T. and Misra S. Role of Engineers to Improve Quality ofConcrete Structures. Proceedings of EASEC-8, 2001.10[2] Izumi S. et al. Non-destructive Inspection of Concrete using HighEnergy X-ray CT/DR. Proceeding of 54th General meeting of JSCE, Vol.
5, JSCE, 1999.9 (in Japanese).
[3] Hirata T. et al. Application of High Density Ultra-sonic Measurement toInspect Internal Defects of Concrete. SEIKEN Leaflet 308, IIS,
University of Tokyo, 2001.6 (in Japanese).
[4] Concrete Committee. The Standard Specification for Construction
Works of Concrete Structures. JSCE, Jan. 2000 (in Japanese).
[5] Concrete Committee. References for “The Standard Specification forConstruction Works of Concrete Structures. JSCE, Jan. 2000 (inJapanese).
[6] Concrete Committee. The Standard Specification for Maintenance ofConcrete Structures. JSCE, Jan. 2001 (in Japanese).
APPENDIX
The contents of the Standard Specifications for Concrete Structures (2002)“Structural Performance Verification” are reproduced below:
Chapter 1
Chapter 2
Chapter 3
Chapter 4
Chapter 5
Chapter 6
Chapter 7
Chapter 8
Chapter 9
Chapter 10
Chapter 11
Chapter 12
Chapter 13

General
Basic of design
Design values for materials
Loads
Structural analysis
Verification of structural safety
Verification of serviceability
Verification of fatigue resistance
General structural details
Prestressed concrete
Composite steel and concrete structure
Design of members
Strut-and-tie model

Introduction to JSCE Standard Specification for Concrete Structures
277

21

October 2004, Agra, India
The contents of Standard Specifications for Concrete Structures (2001)“Maintenance” are reproduced below:
PART 1: MAINTENANCE
Chapter 1
Chapter 2
Chapter 3
Chapter 4
Chapter 5
Chapter 6
Chapter 7
Chapter 8
Chapter 9
Chapter 10
Chapter 11
Chapter 12GeneralRequired performance for concrete structures
Basic principles for maintenance
Identification of deteriorating mechanism
Initial inspection
Routine inspection
periodic inspection
Detailed inspection
Extraordinary inspection
Techniques of testing and surveying
Remedial measures
Records

PART 2: STANDARDS FOR MAINTENANCE
Chapter 13
Chapter 14
Chapter 15
Chapter 16
Chapter 17
Chapter 18
Chapter 19

22Standard maintenance method for carbonation induced
deterioration
Standard maintenance method for chloride induced
deterioration
Standard maintenance method for frost attack
Standard maintenance method for chemical attack
Standard maintenance method for alkali aggregate reaction
Standard maintenance method for fatigue of RC slab of roadbridgeStandard maintenance method for fatigue of RC beam ofrailway bridge

New Technologies for Urban Safety of Mega Cities in Asia
278



RECENT ADVANCES IN ASSESSMENTTECHNOLOGY OF INFRASTRUCTURES IN
KOREA
KEUN JOO BYUN
Yonsei University, Seoul, Korea
byun@yonsei.ac.kr
ABSTRACTInfrastructures are very important, capital equipments for a country.
In spite of their importance, Korea is still suffering from the global
competitiveness of the infrastructures nowadays. This would lead the role ofgovernment in investment and maintenance for our social overhead capital(SOC) to be increased.
While most of developed countries have continually invested on
expansion of the SOC and development of the assessment technology for
their infrastructures, we have just recognized the need of investment for
maintenance and assessment of the infrastructures in the 1990’s andrecently started to propose high-tech health monitoring systems andassessment technologies for our infrastructures.
In this paper, we present the status of assessment techniques for our
infrastructures and also introduce a road map for the development of anassessment technique in a long-term point of view including the service life
prediction technique, durability ꞏserviceability ꞏload-carrying capacity
assessment technique, health monitoring technique, and safety assessment
technique.
1.0 INTRODUCTION
The SOC is an infrastructure that offers the basis of national economic
activities. Hence, principal infrastructures (road, railroad, harbor, airport,etc.) would be appropriately supplied and continuously maintained for the
global competitiveness, and an assessment technique for the infrastructures
would be also systematically developed for the effective investment of
infrastructures as well. That is because the collapse and reconstruction of
the infrastructures are able to lead not only human life and property to belost, but also national economy to be damaged, for examples.
As the construction business has been rapidly grown with theconstruction boom of Middle East in the 1970's, a lot of infrastructures in
Korea have been constructed in a short time period due to the increased
demand for the infrastructures along with the high growth of economy.
However, it is true that the investment for developing an assessment
technique has been rather neglected compared with the quantitative growthof the SOC projects (Oh and Park, 2000).

65
279

October 2004, Agra, IndiaIn this paper, an assessment technique for the Korean infrastructuresand its road map are introduced for the effective investment of theinfrastructures.
2.0 CURRENT STATUS OF INVESTMENT AND ASSESSMENTTECHNOLOGY FOR INFRASTRUCTURES
2.1 Current status of investment in infrastructures
The SOC investments have been increased to stimulate the economic
activities and to strengthen the global competitiveness. In 2002, the SOC
investment against gross domestic product (GDP) of Korea is 17.7% of the
Korean GDP. Figure 1 shows the ratios of the SOC investments against thenational budgets between 1995 and 2002. Figure 2 shows the statistics of theinfrastructures in Korea. As shown in Figure 1, the demand for the
infrastructures and national investments are increasing by about 2% every
year. Although Figure 1 is not enough to completely show a comparison
with the developed countries, it still shows that the SOC projects have great
importance as a fundamental interest in Korea (Ministry of Construction andTransportation, 2001).
(%)
20

17.7 %
15.8 %
14.0 %

15
12.3 %
10.3 %

10
6.7 %

5

0

1995

1997

1999

2000

2001

2002



Figure 1: Ratio of investment in SOC to national budget
Harbors, Waterways (6.6%)
Building (25.0%)

Water supply and drainage (9.1%)
Infra
Structures

Railroad (12.5%)

Road (46.3%)
Dam (0.5%)

Figure 2: Statistics for infrastructures in Korea

66

New Technologies for Urban Safety of Mega Cities in Asia
280

ICUS Report 6


2.2 Current status of assessment technology of infrastructures
For several decades, the need of the SOC expansion has consistently
existed, and the demands for construction of the infrastructures, such as
bridge, road, railroad, harbor and bay, dam, waterway, water supply anddrainage system, and underground structure have also rapidly increased. As
for their effective maintenance, some research institutes (e.g., specified
organizations and structural consultant companies) have carried out the SOC
assessment, but the results are not enough for the current Korean
infrastructures. Figure 3 shows the levels of design, construction, andmaintenance technologies of infrastructures in Korea. It is also shown thatthe maintenance techniques of infrastructures (road, bridge and tunnel) in
Korea are only ranging from ~67% to ~72% in comparison of thetechnically developed countries (Oh and Park, 2000).

Technically developed countries

100

road
bridgetunnel

80

75

70

65

60

DesignConsturction

Maintenance

Figure 3: Level of design, construction, and maintenance of infrastructuresin Korea
Until the 1960’s, the developed countries has spent a lot of costs forthe replacement of infrastructures because of the lack of the SOC
assessment and maintenance systems. However, since the 1980’s, thedeveloped countries have consistently conducted researches to develop the
efficient maintenance technologies for the infrastructures. As a result of thedevelopment of partially integrated SOC maintenance systems, thedeveloped countries were able to get rid of the inefficiency due to double
investments and reconstructions. In case of the United Kingdom, the SOC
investment in the maintenance and assessment systems had already been up
to 28% of the total construction volume in 1973 and reached out 38% in
1983. However, the SOC maintenance and assessment costs in Korea were
only 8% of the total construction volume. This means that the international
competitiveness of overall management of the infrastructures in Korea wasvery low in 1983. It was from the middle of the 1990’s in which theimportance and the necessity of investment for maintenance and assessmentof infrastructures were understood and made researchers in the academies

Recent Advances in Assessment Technology of Infrastructures in Korea
281

67

October 2004, Agra, Indiaconduct basic researches on the durability, serviceability and life cycle costof infrastructures in Korea. Then, theses efforts made possible for extensive
researches on integrated analysis, design and construction, and maintenancesystem for infrastructures. Recently, completed National Technology Road
Map (NTRM) considers an essential technology in advanced infrastructure
construction technologies and Korean government continuously invests forthe technical developments of maintenance and assessment in theinfrastructures (Byun, 2003).

38 %

UK
26 %

Germany

21.7 %

Japan

15.8 %

USA
Korea
0

8%
10

20

30

40

50

Figure 4: Comparison of investment in maintenance to total construction
volume.
3.0 ROADMAP
IN
ASSESSMENTINFRASTRUCTURES IN KOREATECHNOLOGY

OF

3.1 Master plan
As for the systematic assessment of infrastructures, it is necessary todevelop the assessment technologies of infrastructures based on theapplication of a new technique and the development of new inspection
equipments. An investment from the government for efficient maintenanceof infrastructures is also essential. Requirements of the master plan todevelop assessment technologies are as follows:






68

The assessment technique must be compatible with generalmaintenance system of infrastructures.
The technique must be set as the objective of standardization
because nonstandard techniques may induce additional expense.
The technique must be innovative, intelligent developments
including the integration with IT technology and database of
information.
In order that all users are easy to use, the automatic measuring
technique is essential.
The developed individual technique on the element level must be
utilized with a good application and be able to commonly expand.

New Technologies for Urban Safety of Mega Cities in Asia
282

ICUS Report 6

Hence, the assessment technique must be a generalized technique withthe capacities of analysis, estimation, and management during the service
period.
3.2 Road map
As for the effective management of infrastructures, the optimized
assessment technique is essential. To achieve this purpose, four
requirements must be focused as shown in Figure 5. (1) health monitoring
technique, (2) safety assessment technique, (3) durability assessment
technique, and (4) modeling for service period and life time. Through thesetechniques, the unified assessment system for infrastructures can beestablished, so that the advanced assessment technology for infrastructures
under various conditions can be integrated and widely used. Figure 5 shows
the road map of related researches on the assessment technology.

Safety of infrastructures

Systematic maintenanceof infrastructures

Health monitoring technique• The new non-destructive inspection
technique & application• Multi deterioration monitoring• Monitoring & diagnosis manual• Integrated monitoring system

Infra technique

Safety assessment technique• Definition of safety assessment
theory• Optimum module for safetyassessment• Development of S/W system

Element technique
Durability assessment
technique

Practical technique• Status of durability assessment
techniques• Durability improvement technique• Computational equation using
proposed correction factors• Manual of durability assessment

Infrastructure assessment technique

Modeling technique forservice period and lifetime• Definition of service period andlifetime• Modeling, analysis, assessment
technique• Modeling technique for timedependent integration analysis• Information-communication technique• Sensor / Monitoring technique• Education & Certification system• Database for assessment of infrastructures• Design and construction technique• Material technique• Risk management technique

Advanced Assessment Technique of Infrastructures

Figure 5: Road Map of related research on assessment technology
4.0 CONCLUSION

Recent Advances in Assessment Technology of Infrastructures in Korea
283

69

October 2004, Agra, India
There exist many subjects to improve for the assessment technologies
of infrastructures. Recently, the advanced assessment technologies including
health monitoring technique, safety assessment technique, durability
assessment technique, and modeling technique for service period life time
are proposing in Korea as the first stage.
In this paper, a technical road map on the assessment technology ofinfrastructures was proposed. A main concept of the road map is theintegration of individual developments and combination of all the related
technologies even in initiation stage of the research. The ultimate goal ofthese techniques is to develop an advanced assessment technique of
infrastructures in Korea.
REFERENCES
Byun, K. J., Kim, M. K., and Song, H. W., 2003. Advanced Lifeline Systems
in Korea. Proceedings of the 2nd International Symposium on New
Technologies for Urban Safety of Mega Cities in Asia, ICUS/INCEDE.
Kim, M. K., and Byun, K. J., 1999. The Status of Bridge Maintenance in
Korea. Korean Society of Civil Engineers.
Lee, H. E., and Choi, H. J., 1999. Sensitivity of Time Domain Modal
Identification Technique to Measurement Noise and It’s Application to
Cable Stayed Bridges. 5th Korea-Japan Joint Seminar on Steel Bridges.
Ministry of Construction and Transportation, 2001. Development of Design& Construction Guide for Strengthening Method and Standardization of
Load-carrying Capacity Assessment Technique.
Oh, K. C., and Park, K. C., 2000. Evaluation Procedure on Concrete
Durability in Korea. ACI, The Forth ACI/KCI International Conference,
37-46.
Sim, J., Song, H. W., and Hong, S. G., 2001. Concrete Technology in Korea.
Workshop on Concrete Issues in Asia, Asian Concrete Forum, Sapporo,
Japan, 27-32.
Song, H. W., Byun, K. J., and You, D. W., 2000. Evaluation of Retrofitted
Capacity of Deteriorated Reinforced Concrete Beams. ACI
Supplementary paper, 47-64.

70

New Technologies for Urban Safety of Mega Cities in Asia
284

ICUS Report 6

A RISK-BASED DECISION SUPPORTSYSTEM FOR INSPECTION AND
MAINTENANCE OF CROSS-COUNTRYPETROLEUM PIPELINESPRASANTA KUMAR DEY1 AND STEPHEN O. OGUNLANA2
1
University of the West Indies, Bridgetown, Barbados, West
Indies2
Asian Institute of Technology, Pathumthani, Thailand
ogunlana@ait.ac.th
ABSTRACT
Pipeline failure can have devastating effect on the health andlivelihood of people living within the pipeline corridor. The existing
method of pipeline health monitoring, which requires an entire
pipeline to be inspected periodically, is unproductive. A risk-based
decision support system (DSS) that reduces the amount of time spenton inspection has is presented.
The risk-based DSS uses Analytic Hierarchy Process (AHP), a
multiple attribute decision-making technique, to identify the factorsthat influence failure on specific segments and analyzes their effects
by determining probability of risk factors. The severity of failure isdetermined through consequence analysis. From this, the effect of a
failure caused by each risk factor can be established in terms of cost,
and the cumulative effect of failure determined through probability
analysis. The technique does not totally eliminate subjectivity, but it
is an improvement over the existing inspection method selection.
1.0 INTRODUCTION
Cross-country pipelines are the most energy-efficient, safe,
environmentally friendly, and economic way to ship hydrocarbons(gas, crude oil, and finished products) over long distances, either
within the geographical boundary of a country or beyond it. A
significant portion of many nations’ energy requirements is now
transported through pipelines. The economies of many countries
depend on the smooth and uninterrupted operation of these lines, so it
is increasingly important to ensure the safe and failure-free operationof pipelines.
While pipelines are one of the safest modes of transporting bulk
energy, and have failure rates much lower than the railroads or
highway transportation, failures do occur, and sometimes withcatastrophic consequences. A number of pipelines have failed in the
recent past, with tragic consequences. In 1993 in Venezuela, 51

A Risk-Based Decision Support System for Inspection and Maintenance of Cross-country Petroleum Pipelines285

1

October 2004, Agra, India

people were burnt to death when a gas pipeline failed and theescaping gas ignited. Again in 1994, a 36-inch (914 mm) pipeline in
New Jersey failed, resulting in the death of one person and more than
50 injuries. Similar failures also have occurred in the UK, Russia,
Canada, Pakistan, and India (Hopkins 1994). While pipeline failure
rarely causes fatalities, disruptions in operation lead to large businesslosses. Failures can be very expensive and cause considerable
damage to the environment.
Traditionally, most pipeline operators make safety provisions
for a theoretical minimum failure rate for the life of the pipeline atthe design stage. Safety is considered when selecting pipes and otherfittings. To prevent corrosion, providing a high resistance externalcoating materials electrically isolates a pipeline. As a secondary
protective measure, a low-voltage direct current is impressed in thepipe at pre-calculated distance to transfer any corrosion that occurs
due to breaks in the coating caused by a heap of buried iron junk,rails, etc. This is called impressed current cathodic protection. The
quality of the commodity that is being transported through the line isalso ensured, and sometimes corrosion-preventing chemicals(corrosion inhibitors) are mixed with the commodity. To avoid
deliberate damage of the pipeline in isolated locations, regularpatrolling of the right-of-way from the air as well as on foot is carriedout, and all third party activities near the route are monitored.
Various techniques are routinely used to monitor the status of apipeline. Any deterioration in the line may cause a leak or rupture.
Modern methodologies can ensure the structural integrity of an
operating pipeline without taking it out of service (Jamieson, 1986).
The existing inspection and maintenance practices commonly
followed by most pipeline operators are formulated mainly on thebasis of experience. However, operators are developing an organized
maintenance policy based on data analysis and other in-house studies
to replace rule-of-thumb based policies. The primary reasons for thisare stringent environmental protection laws (DOT, 1995), scarce
resources, and excessive inspection costs. Existing policies are notsharply focused from the point of view of the greatest damage/defectrisk to a pipeline. The basis for selecting health monitoring andinspection techniques is not very clear to many operators. In manycases, a survey is conducted over an entire pipeline or on a particularsegment, when another segment needs it more. Avoidable
expenditures are thus incurred.
A strong reason exists, therefore, to derive a technique that will
help pipeline operators select the right type of inspection/monitoring
technique for segments that need it. A more clearly focused
inspection and maintenance policy that has a low investment-tobenefit ratio should be formulated.
2
in Asia

New Technologies for Urban Safety of Mega Cities

286

ICUS Report 6

This article introduces a DSS for predicting the risk factor for
pipeline failures. This model allows management to formulate a costeffective, customized, flexible, and logical inspection model. It isestablished through risk analysis, with the application of the analytic
hierarchy process (AHP) (Saaty 1980).
2.0 THE ANALYTIC HIERARCHY PROCESS
Risks are by nature subjective, so to analyze their potential
contribution to a failure, the AHP developed by Saaty (1980) is used
here. This technique allows subjective and objective factors to beconsidered in risk analysis and also provide a flexible and easily
understood way to analyze subjective risk factors. It is a multiple
criteria decision-making technique that permits the active
participation of those involved, and provides managers a rational
basis on which to make decisions.
Formulating the decision problem in the form of a hierarchicalstructure is the first step. In a typical hierarchy, the top level reflects
the overall objective (focus) of the decision problem. The elements
affecting the decision are represented in intermediate levels. The
lowest level comprises the decision options. Once the hierarchy has
been constructed, the decision-maker begins the prioritization
procedure to determine the relative importance of the elements ineach level of the hierarchy. The elements in each level are comparedpair-wise with respect to their importance in making the decision
under consideration. The verbal scale used in AHP enables thedecision-maker to incorporate subjectivity, experience andknowledge in an intuitive and natural way.
After the comparison matrices have been created, the process
moves on to the phase in which relative weights are derived for thevarious elements. The relative weights of the elements of each levelwith respect to an element in the adjacent upper level are computed
as the components of the normalized eigenvector associated with thelargest eigenvalue of their comparison matrix. The composite
weights of the decision alternatives are then determined byaggregating the weights through the hierarchy. This is done byfollowing a path from the top of the hierarchy to each alternative at
the lowest level, and multiplying the weights along each segment of
the path. The outcome of this aggregation is a normalized vector of
the overall weights of the options. The mathematical basis fordetermining the weights has been established by Saaty (1980).
The AHP has been applied to pipeline project control (Dey etal., 1994), route selection (Dey and Gupta, 2000) and feasibility
analysis (Dey, 2001).

A Risk-Based Decision Support System for Inspection and Maintenance of Cross-country Petroleum Pipelines287

3

October 2004, Agra, India

3.0 METHODOLOGY
The methodology adopted in this study involves the following
steps.
Step 1: Cross-country petroleum pipeline passes throughvarious terrains and requires originating and a few intermediatepumping stations for transporting petroleum products or crude oil.
Therefore, the entire pipeline is classified into a few stretches(preferably in line with its natural stretch i.e. pipeline sections in
between two stations).
Step 2: All information related to the pipeline including theterrain detail under study is prepared and documented section wise.
Step 3: Risk factors that can cause failures are identified.
Generally, pipelines fail because of one of these reasons: (i)corrosion; (ii) external interference; (iii) construction and materials
defects; (iv) acts of God; and (v) human and operational error.
Step 4: A risk structure model is formulated in the AHP
framework. Based on the identified risk factors, a hierarchical risk
structure is formed (see Figure 1). The goal here is to determine therelative likelihood of pipeline failures. Level II is criteria (riskfactors), level III is sub-factors, and level IV is alternatives (thepipeline stretches). Figure 1 shows the AHP model for analyzing risk
from a failure perspective.
Step 5: Comparison between pairs of risk factors and subfactors are done to determine the likelihood of pipeline failure due toeach factor and sub-factor.
Step 6: Pair wise comparison of alternative pipeline stretches,with respect to each risk factor, to determine the likelihood of failure
for each pipeline stretch due to each factor is done.
Step 7: The results are synthesized across the hierarchy todetermine the likelihood of failure of a pipeline stretch and relative
comparison with other stretches from failure perspectives.
Step
8:
Determine
specific
inspection/maintenancerequirements for specific segments, to mitigate risk.
Step 9: Determine the expected failure cost of each line by aMonte Carlo simulation.
Step 10: Establish a cost-benefit analysis to justify the
proposed investment, to suggest design, construction and operation4
in Asia

New Technologies for Urban Safety of Mega Cities

288

ICUS Report 6

improvement of future pipelines and to formulate a cost-effective
insurance plan for pipeline.

Determining the probabilityof failure of pipeline stretches

Sub-factors

Factors

Goal

Alternatives

Corrosion

External
interference

Construction &materials defect•External
corrosion•Third party
activities•Construction
defect•Human error•Internal
corrosion•Pilferage•Poor materials•Operational
error

Pipeline
stretch 1

Pipeline
stretch 2

Pipeline
stretch 3

Acts of God

Pipeline
stretch 4

Others

Pipeline
stretch 5

Figure 1: Hierarchical risk structure
4.0 APPLICATIONThe entire methodology has been illustrated by a case study
application. For reasons of space, only the first seven steps in themethodology are demonstrated in this paper. A crude oil pipeline(length 1500 km) in the western part of India was studied. The
throughput of the pipeline is 9 million metric ton per annum(MMTPA) with augmentation capability of 12 MMTPA, having
three intermediate booster stations and a offshore terminal. The
schematic of the pipelines is shown in Figure 2. The pipeline is 19
years old and has a history of corrosion failure. The poor condition of
the coating, as revealed during various surveys and an unreliable
power supply to cathodic protection stations are the reasons for this.
The line passes through long stretches of socio-economically
backward areas and is vulnerable to pilferage and sabotage. In someregions, the right-of-way is shared with other agencies, as such, thechance of external interference is high. Failure data revealed
numerous pre-commissioning failures, raising doubts about thequality of construction.
The risk analysis model for the pipeline is formulated byapplying the methodology described above. The entire pipeline wasclassified into five stretches. The risk structure and pair wisecomparisons were established through a workshop of the executives
who operate various pipelines. Thirty executives participated, eachhaving more than 15 years of experience in pipeline operations.

A Risk-Based Decision Support System for Inspection and Maintenance of Cross-country Petroleum Pipelines289

5

October 2004, Agra, India

Originating
Pump station
Off-shore terminalIntermediate
Pump station
PLS4

Crude oil
from
Ship

Pipelines

Tank farm

PLS5

PLS3

Intermediate
Pump station

Single buoy
mooring

Intermediate
Pump station
PLS2

PLS1
Tank farm in Refinery

Pumping units

To oil Refinery
PLS - Pipeline Stretch

Figure 2: Schematic of oil pipelines
Before formulating the model, they were given full knowledgeof pipeline conditions through the database of various pipeline
stretches (Table 1) and pipeline record sheet.
A decision-maker can express a preference between each pairas equal, moderate, strong, very strong, and extremely preferable(important). These judgments can be translated into numerical values
on a scale of 1 to 9 (Table 2). Elements at each level of hierarchy arecompared with each other in pairs, with their respective “parents” at
the next higher level. With the hierarchy used here, matrices of
judgments are formed. A brainstorming session was held to compare
the risk factors. The pipeline executives established a common
consensus for the AHP hierarchy, pair wise comparison in factors,
sub-factors and alternative levels through group decision making.
Disagreements were resolved through reasoning and collecting more
information. Their hierarchy contained the details necessary for risk
analysis. Table 3 shows the matrix of judgments that resulted.
The final outcomes of each of the pipeline stretch against therisk factors are summarized in Table 4. Both local probability andglobal probability for each of the five stretches are summed up to
derive the probability of a pipeline stretch failure and its position
with respect to other stretches. The results of the analysis (Table 4)
reveal that the chances of pipeline failure due to corrosion andexternal interference are greater than other factors.

6in Asia

New Technologies for Urban Safety of Mega Cities

290ICUS Report 6

Table 1: Database of pipeline stretches (figures in km)
Description

Pipe LS 1

Pipe LS2

Pipe LS3Pipe
LS4

Pipe LS5

Length

260

210

180

230

25

Normal

170

95

35

169

7

Slushy36
115

20

Terrain detail:Rocky(hilly)
River
&
canal
crossings
Populated

4

2

6

50

88

35

Offshore

18

Coal belt

25

ForestSoilcondition
3rd
party
activities
Chances ofpilferage

30
corrosive

corrosive

Higherdue topopulated
area

More due
to coal belt
Higher due
topopulated
area

Construction
complexity

Less
corrosive

More dueto rockand forest

Less
corros.
Higherdue topopulated areaMore
due toriver
crossing

Operational
complexity

A Risk-Based Decision Support System for Inspection and Maintenance of Cross-country Petroleum Pipelines

291

Less
corrosive

More duetooffshorepipingMore duetooffshoreterminal7

October 2004, Agra, India

Table 2: Scale of relative importance for pair-wise comparison
Intensity

Definition

Explanation

1

Equal importance359Moderate importance
Essential or strong
importance
Demonstrated
importance
Extreme importance

Two activities contribute equallyto the object
Slightly favors one over another
Strongly favors one over another

2, 4, 6, 8Intermediate values

7

Dominance of the demonstrated
in practiceEvidence favoring one overanother of highest possible orderof affirmation
When compromise is needed

Table 3: Pair wise comparison in factor level
Factors

Corrosion

External
Interfere
nce

Construction& materials
defectActs ofGod

OthersLikelihood

Corrosion

1

2

3

7

3

0.40

External
Interference

1/2

1

3

5

3

0.29

Construction &materials
defectActs of God

1/3

1/3

1

3

2

0.14

1/7

1/5

1/3

1

1/4

0.05

Others

1/3

1/3

1/2

4

1

0.12

The following additional observations were made from the risk
analysis study:The pipeline stretches 1 and 2 are vulnerable from external
corrosion due to slushy terrain, whereas pipeline stretches 4
and 5 are vulnerable to internal corrosion due to long
submerged pipe sections.
External interference due to the third party activities is amajor problem in pipeline stretches 2 because of coal mining
activities, whereas in stretches 4, it is due to major rivercrossings and canal crossing.

8
in Asia

New Technologies for Urban Safety of Mega Cities

292

ICUS Report 6External interference due to malicious reasons prevail in
stretches 1 and 2 because they pass through a long and highly
populated industrial areas.
The pipeline stretch 3 passes through mostly rocky terrain,
exposing the pipe to various types of failure due toconstruction and poor materials. As this stretch is vulnerable
to subsidence problem, the likelihood of pipeline failure fromacts of God is quite high along with high chance of failure
due to construction defect and poor materials.
The stretch 5, i.e. the offshore pipeline is very sensitive tooperational and human errors as well as failure due to various
natural calamities.
All pipeline stretches are ranked with respect to their failurechances, the failure prone pipeline stretches 5, 1, 2, 4, and 3
in decreasing order of vulnerability.



Table 4: Likelihood of failure of various pipeline stretches
PLS1

PLS2

PLS3

PLS4

PLS5

External

Likelihood
0.221

0.108

0.064

0.007

0.011

0.031

Internal

0.181

0.038

0.022

0.020

0.042

0.060

3rd party
activities
Malicious

0.186

0.030

0.078

0.011

0.061

0.006

0.100

0.033

0.039

0.005

0.018

0.005

Construction defects
Poor mats.

0.072

0.012

0.007

0.028

0.007

0.018

0.072

0.006

0.007

0.027

0.016

0.017

0.05

0.006

0.001

0.014

0.006

0.020

0.048
Human
error
Operational 0.072
error
Likelihood of failure of various pipeline
stretches
Ranking

0.001

0.005

0.003

0.008

0.030

0.001

0.003

0.009

0.003

0.056

0.236

0.227

0.123

0.172

0.242

2

3

5

4

1

Factors
Corrosion

Likelihood
0.40

External
Interferen
ce

0.29

Constructi
on & mat.
defect0.14

Acts ofGod

0.05

OthersSub-factors

0.12

PLS – Pipeline stretch
5.0 SUMMARY AND CONCLUSIONSAs pipelines pass through varied terrain, the condition ofpipelines varies widely across the entire length and throughout theservice life. Inspecting entire pipelines through specific a inspection
methodology/ tool cannot detect problems in the entire length as
inspection tools are designed to detect specific problems only. On the
A Risk-Based Decision Support System for Inspection and Maintenance of Cross-country Petroleum Pipelines

293

9

October 2004, Agra, India

other hand, inspecting the entire pipeline by various tools to detect
the entire associated problems is not cost effective.
A decision support system (DSS) model in AHP framework,
which determines the likely problems associated with each stretchwith the involvement of the experienced pipeline operators has beenpresented. This leads to the development of a cost-effective
inspection and maintenance strategy for the pipelines. The same
methodology can be used for any operating unit to develop strategic
DSS for inspection and maintenance.
The method of analysis described here can be used to: (i)reduce subjectivity in the decision making process when selecting aninspection technique; (ii) identify the right pipeline or segment for
inspection and maintenance; and (iii) demonstrate the risk level togovernments and other regulatory agencies.
The technique does have limitations, because subjectivity is nottotally eliminated. For instance, the weightage against each of the
failure factors is based upon experience, available data andperception of the pipeline executives and decision-makers. Despite
these limitations, a cross-country petroleum pipeline inspection andmaintenance policy formed on the basis of the methodology can be
an effective tool to mitigate risk
REFERENCES
Dey, P K, Tabucanon, M T, and Ogunlana S O., 1994. Planning for
project control through risk analysis: a case of petroleum
pipeline laying project. International Journal of ProjectManagement, 12:1, 23-33.
Dey, P. K. and Gupta, S. S., 2000. Decision support system yields
better pipeline route. Oil and Gas Journal, 98.22:10, 68-73, May
29.
Dey, P K., 2001. Integrated approach to project feasibility analysis:
a case study. Impact Assessment and Project Appraisal,
Forthcoming 2001.
Hopkins, P., 1994. Ensuring the Safe Operation of Older Pipelines.
International Pipelines and offshore Contractors Association, 28th
Convention. September.
Jamieson, R. M., 1986. Pipeline Integrity Monitoring. Pipeline
Integrity Conference Aberdeen, Scotland. October 29-30.
Saaty, T. L. The Analytic Hierarchy Process. New York: McGrawHill, 1980.
Pipeline Safety Regulations.Department of Transportation(US), 1st
October 1995.

10
in Asia

New Technologies for Urban Safety of Mega Cities

294

IMPACT RESISTANCE OF
FRP-CONCRETE SANDWICH PANELSKIANG HWEE TAN
Department of Civil Engineering,
National University of Singapore, Singapore
cvetankh@nus.edu.sg
ABSTRACT
Structures may be subjected to impact loads caused by events likeearthquakes or strong winds or terrorist acts or accidents, during theirservice life. This study examined the use of fiber-reinforced polymer (FRP)
panels and FRP-concrete sandwich panels to resist impact loads. Repeatedimpact tests using a hemispherical impactor of 43 kg falling from a height of
4 m in a drop-weight test rig, were carried out on square panels of different
thicknesses, with or with concrete, and with carbon and glass FRPs as thereinforcing material. Both the FRP and FRP-concrete sandwich panels
exhibited good impact characteristics in terms of resisted impact force,
impulse and energy absorption capacity. For FRP panels, the impact
resistance improved with the number of plies of FRP sheets. On the other
hand, the impact resistance improved with the thickness of the FRP systemin the case of glass FRP-concrete panels but not for the carbon FRPconcrete panels, due to the brittleness of carbon fibers under transverse
shear. A 5-mm thick concrete panel sandwiched between two 4-ply glass
FRP sheets suffered a punch through failure only after twelve impacts.
1.0 INTRODUCTION
Concrete structures may be subjected to impact or impulsive loads
during their service life due to falling or flying objects, due to events such as
earthquakes, strong winds, explosions or vehicular accidents. These include
protective structures to shield motorways from falling rocks, or bridge decks
and piers against impact by vessels (Struck and Voggenreiter, 1975). They
also include defence shelters, ammunition bunkers, and firing ranges, which
are designed to resist small weapon effects or sometimes, fragmentationfrom small bombs.
The objective of this study is to examine the impact resistance offibre-reinforced polymer (FRP) and FRP-concrete panels, thereby
determining the suitability of the material in protective works. The
advantages of using FRP systems are its low unit weight, and its installation
speed. To achieve the objective, a series of impact tests using a drop-weighttest rig was conducted on FRP panels as well as FRP-concrete sandwich
panels. The test parameters included two types of FRP composites, and thethicknesses of the FRP and concrete layers. The impact resistance was
evaluated in terms of resisted impact load, impulse, energy absorption
capacity and number of impacts to failure.

131
295

October 2004, Agra

2.0 TEST PROGRAMME
Two series of specimens, as shown in Table 1, were prepared. Series
P consisted of FRP panels, each measuring 1000 mm by 1000 mm on plan,and made with four, six or ten plies of carbon or glass fibre sheets. Series S
comprised FRP-concrete sandwich panels, in which a concrete lay, 5 or 10
mm thick, was bonded with two or four plies of glass or carbon FRP sheetson each face. The FRP sheets were of uni-directional fibres, and were laid
ply by ply in alternating orthogonal directions.

SeriesTable 1: Test Specimens

P

S

Specimen
Designation

Concretethickness
(mm)

PC4
PC6
PC10
PG4
PG6
PG10
SC25
SC45
SC210
SG25
SG45
SG210

5
5
10
5
5
10

Type of FRP Measured FRP
Reinforcement thickness (mm)No. of
FRP
plies

Carbon sheet
Carbon sheet
Carbon sheet
Glass sheet
Glass sheet
Glass sheet
Carbon sheet
Carbon sheet
Carbon sheet
Glass sheet
Glass sheet
Glass sheet

4
6
10
4
6
10
2x2
2x4
2x2
2x2
2x4
2x2

3.45
5.75
10.14
5.75
6.95
10.61
9.52
12.31
14.14
13.40
16.50
17.29

2.1 Materials
Ordinary Portland cement, potable water and natural river sandpassing through 4.75 mm sieve, were mixed in the proportion of 1:2:0.5 toform the mortar concrete layer in Series S specimens. As specified by the
manufacturers, the carbon fibre sheet weighs 300 g/m2, and has a design
thickness of 0.165 mm, and a tensile strength of 3500 MPa, with a modulus
of elasticity of 230 GPa and a rupture strain of 1.5 %. The glass fibre fabrichas a weight of 900 g/m2 and design thickness of 0.355 mm, tensile strengthof 1700 MPa, and rupture strain of 2.0 %. The primer and saturant for thebonding of the fibre sheets were each supplied in two parts, consisting of amain and a hardening agent, to be mixed in the ratio of 3:1 by weight.
2.2 Fabrication of Specimens
A template for making the FRP panels was constructed. It consistedof two aluminum strips set 1000 mm apart and adhesively attached to aplastic sheet placed on a wooden plank. A piece of Perspex was used toform the third side. The plastic sheet was waxed to facilitate demoulding.
The first FRP sheet was then placed onto the plastic sheet and taped down
on one edge. The FRP sheet was flipped over and saturant was applied to132

New Technologies for Urban Safety of Mega Cities in Asia
296

ICUS Report 6

the bottom plastic sheet. The FRP sheet was then flipped back onto theplastic sheet, and a coat of saturant was applied. Care was taken to flatten
the FRP sheet so as to prevent any air voids from appearing. The second
FRP layer was laid in the orthogonal direction, and the same procedure wasrepeated, until the required number of plies of FRP sheet was placed. After
that, a piece of perspex was placed with some weights on the FRP panel, toachieve uniform thickness. The panel was left to cure overnight anddemoulded the next day. Mild steel plates measuring 50 mm wide and 2
mm thick were bonded along the four edges of each panel to facilitate
clamping down during testing.
In the case of sandwich panels, the concrete layers were cast in
wooden formwork, demoulded after a day, and placed under wet gunnysacks for 7 days. Six 100 mm cubes were also cast and cured in the samemanner for each panel for the purpose of strength determination. After theconcrete panels had gained sufficient strength, they were ground on both
faces using a sandpaper grinder. Primer was applied to one of the faces
evenly and allowed to dry before the FRP sheets were installed, taking careto remove air bubbles and excess saturant using a roller. The installed FRP
sheets were left to cure. The specimen was turned over the next day and theprocess of FRP installation was repeated on the other face of the concrete
layer to form the sandwich panel.
2.3 Test set-up and instrumentation
The impact tests were carried out using a drop weight test frame,
consisting of a square horizontal frame welded to columns which werebolted on to the floor. Each panel was placed on the horizontal frame onfour edges with its centre aligned with the impactor. The panel was
restrained at the supports using steel bolts and/or clamps. Electrical strain
gauges and potentiometers were used to measure strains and displacements
during impact, near the center of the specimen, as shown in Fig 1.

Figure 1: Location of strain gauges and potentiometers (plan view)

Impact Resistance of FRP-Concrete Sandwich Panels
297

133

October 2004, Agra

For each test, a 43-kg striker with a hemispherical head was raised to aheight of 4 m and allowed to drop under its free weight on the centre of thespecimen. Its line of fall was kept in the vertical direction by smooth rollers
running along the aluminum guides. An accelerometer was fixed at the tipof the impactor to measure its deceleration and hence the impact force. The
impact velocity was measured by two laser diodes. The strain gauges,
potentiometers, laser diodes and accelerometer were connected to a dataacquisition system, and data collection was triggered by the laser diode firstcrossed by the impactor upon release.
The recorded data was filtered to remove electrical noise due to theelectronic systems and the mechanical system. A cut-off frequency of 3
kHz was selected using a trial and error method based on Fast Fourier
Transform (FFT) computation.
3.0 TEST RESULTS AND DISCUSSION
3.1 Behavior of FRP panels
Panels PC4 and PC6 were punched through at the first blow. PG4
took six blows before the potentiometers were damaged. The remaining
panels (PC10, PG6 and PG10) were subjected to a maximum of ten blows.
3.1.1 Failure characteristics
Failure was catastrophic for PC4 and PC6 as the impactor perforated
the carbon FRP panels. The measured FRP strains around the perforation
were as high as 0.8%. Besides rupture of fibres as shown in Fig. 2, inter-ply
delamination between the carbon fibre sheets was observed.

Figure 2: Appearance of FRP panels after failure
3.1.2 Impact force
The impact force on the panel, determined from the mass anddeceleration of the impactor, was found to increase with the panel thickness

134

New Technologies for Urban Safety of Mega Cities in Asia
298

ICUS Report 6

and hence stiffness. For the carbon FRP panels, it measured 80 kN for PC4
and 110 kN for PC6 for the first impact. The value was low at 55 kN for
PC10, but it rose to about 80 kN for the third impact. For the glass FRP
panels, the values were about 32 kN, 68 kN and 75 kN, respectively, for
PG4, PG6 and PG10.
Also, the impact force generally decreased with the number of impacts,
due to the loss of stiffness of the panels. Fig. 3 shows that the loss instiffness appears to be more drastic in carbon FRP panels.
90

3

80
80

4

100 msec

5

70

60

1

50

8

6

2

9

10

7

40
40

Force (kN)

Force (kN)

60

30

20
20
10

0

0
0

100

200

300

400

500

600

700

800

900

1000

-10

-20
-20
-30

Time (ms)(a) PC1090

100 msec

80

80

1

70

2
3

60

4

5

6

50

10

9
7

8

40

Force (kN)

Force (kN)

60

40
30

20

20
10

0

0
0

100

200

300

400

500

600

700

800

900

1000

-10

-20

-20
-30

Time (ms)(b) PG10
Figure 3: Impact force-time characteristics of FRP panels
3.1.3 Impulse
The area under the impact force-time graph gives the impulse, which
is a measure of the intensity of the impact load. Test results indicated thatthe impulse increased with the panel thickness in the initial few impacts.
Thereafter, the impulse was about the same and equal to about 550 Ns
regardless of the type and thickness of the panels, as shown in Fig. 4, in

Impact Resistance of FRP-Concrete Sandwich Panels
299

135

October 2004, Agra

which the value for PC10 at the third impact is probably due tomeasurement error.
1200

Impulse (Ns)

1000
PC10

800
600
400

PG6
PG10
PG4

200
0

2

4

6

8

10

Number of impacts

Figure 4: Impulse on FRP panels
3.1.4 Energy absorption
The maximum instantaneous displacement was lower for thicker
panels as expected. However, the variation in maximum displacement wasobserved to be small for the glass FRP panels tested. Also, despite being
thicker, PG10 registered a slightly higher maximum displacement thanPC10, probably due to the lower modulus of elasticity of glass FRP
compared to carbon FRP. The number of impacts did not affect the
maximum displacement, probably as the panels continued to behave
elastically and there was no permanent deformation.
The energy absorbed and dissipated by the panel was determined fromthe force-time and displacement-time relations. The cumulative energy
absorbed with the number of impact is shown in Fig. 5. Specimen PC10
absorbed the most energy due to a higher impact force. Among the glass
FRP panels, the energy absorbed generally increased with the panel
thickness, although the results of PG4 and PG6 did not differ much.
3.2 Behavior of FRP-concrete sandwich panels
At the time of testing, the concrete compressive strength averaged 54
MPa for carbon and 60 MPa for glass FRP-concrete sandwich panels. All
panels were punched through at the first or second impact, except SG45
which took twelve impacts without failing. The strains measured at thebottom of the carbon FRP-concrete panel near the centre were between 0.3
and 0.7%, with the higher value in the fibre direction of the outermost FRP
ply. The strains were higher in glass FRP-concrete panels at between 1 and
2%, except for SG45 where the strains were lower at between 0.4 and 1%.
The lower strains in carbon FRP-concrete panels indicated that the punching

136

New Technologies for Urban Safety of Mega Cities in Asia
300

ICUS Report 6

Total energy absorbed (kJ)failure was more localized as the load could easily shear through the carbon
FRP sheets.
PC10

16
12

PG10

8

0

PG6

PG4

4

4

2

6

8

10

Number of impacts

Figure 5: Energy absorption capacity of FRP panels
3.2.1 Damage and failure characteristics
The damage to the specimens due to the impacts was observed on the
top face. At the first impact, the top FRP layer was punched through, andthe impactor penetrated easily into the concrete layer. Since SC25 andSC210 each effectively had only two plies of carbon FRP sheets at thebottom and the concrete layer was thin, the impactor immediately punchedthrough the slab. SC45, SG25 and SG210 suffered the same fate at thesecond impact.
For Panel SG45, with a 5 mm thick concrete layer sandwiched
between two 4-ply FRP sheets, a depression was observed at the top face ofthe specimen after several impacts, and the appearance after punching
failure at the twelfth impact is shown in Fig. 6(a). Part of the top FRP
sheets had debonded around the depression, as shown shaded.
Upon
turning the panel over, it was observed that the bottom FRP plies had alsodelaminated near the centre of the slab, and this had spread along the fibre
direction towards the edges as shown in Fig. 6(b). Similar delamination wasobserved in the other slabs that were punched through.
3.2.2 Impact force
In general, the impact force increased with the concrete thickness or
the number of plies of FRP sheet. Also, it decreased with the number ofimpact, as observed from the panels that failed under the second impact,
indicating a deterioration of stiffness due to cracking of the concrete layer.
The impact force-time characteristics for Panel SG45 shown in Fig. 7,
however indicates an unexpected increase in impact force initially, followed
by a drop for subsequent impact beyond the sixth impact. The unexpected
increase could only be attributed to noise interference.

Impact Resistance of FRP-Concrete Sandwich Panels
301

137

October 2004, Agra(a) Top view(b) Bottom view

Figure 6: Appearance of FRP-concrete sandwich panel SG45

140
140

120
120

6

5

100 msec

100
3

8080
Force (kN)

Force (kN)

100

6060

7

2

1

4

8
9

10 11 12

4040
2020
00 0
-20

100

200

300

400

500

600

700

800

900

1000

1100

1200

-20

Time (ms)Figure 7: Impact force-time characteristics of panel SG45
3.2.3 Impulse
The impulse, like the impact force, increased with an increase inthickness in concrete layer or number of FRP ply. In general, the impulseon the glass FRP-concrete panels was higher than that on the carbon FRPconcrete panels, as glass FRP was more resistant to transverse shear andthicker than carbon FRP, sheet by sheet. Fig. 8 shows that the impulse for
SG45 decreased after the sixth impact, due to damage and loss in stiffness.

138

New Technologies for Urban Safety of Mega Cities in Asia
302

ICUS Report 6

800

Impulse (Ns)

600

400

200

0

2

4
6
8
Number of impacts

10

12

Figure 8: Impulse on panel SG45
3.2.4 Energy absorption characteristics
The maximum deflection of the panel under each impact decreased
with the thickness of the concrete and FRP layers in the case of carbon FRPconcrete panels, being about 70 mm, 50 mm and 55 mm under the first
impact, for SC25, SC45 and SC210, respectively. The glass FRP-concrete
panels sustained higher deflections of between 65 to 75 mm, probably due
to the lower modulus of glass FRP, but did not show any clear trend in theinfluence of thickness of the concrete and FRP layers.

Total energy absorbed (kJ)The energy absorption capacity increased with the thickness of either
the concrete layer or FRP layer. The values were 480 J, 1200 J and 720 J
for SC25, SC45 and SC210, and 1350 J, 1500 J and 1500 J for SG25, SG45
and SG210, respectively. The cumulative energy absorbed in Panel SG45 isshown in Fig. 9. The energy absorbed per impact decreased after the eighth
impact, indicating that significant damage had been imparted on the panel.
20
16
12
8
4
0

2

4

6

8

10

12

Number of impacts

Figure 9: Energy absorption capacity of panel SG45

Impact Resistance of FRP-Concrete Sandwich Panels
303

139

October 2004, Agra

4.0 CONCLUDING REMARKS
Carbon FRP panels are more susceptible to punching failure than glass
FRP panels as the fibers are less resistant to transverse shear. However,they provide higher stiffness, thereby enabling the panels to resist higher
impact force and absorb greater energy, when compared to glass FRP panelswith the same number of plies of FRP sheets. Also, the impact resistance
improves with the panel thickness in general, but was not affected by the
number of impact covered in the study.
Similarly, for the sandwich panels, punching failure was more
localized and likely to occur in carbon FRP-concrete panels. The impact
resistance was also found to improve with thicker concrete or FRP layers.
Repeated impacts cause damage to the concrete layer, thereby reducing theresistance of the panel.
ACKNOWLEDGMENT
The study was carried out with the assistance of Mr W. X. Lim, andstaff of the Structural Engineering Laboratory at the National University ofSingapore.
REFERENCES
Struck, W. and Voggenreiter, W. 1975. Examples of Impact and Impulsive
Loading in the Field of Civil Engineering. Materials and Structures, Vol.
8, No. 44, pp. 81-87.

140

New Technologies for Urban Safety of Mega Cities in Asia
304



DURABILITY DESIGN FOR
CONCRETE STRUCTURES FORURBAN SAFETY IN THAILAND
SOMNUK TANGTERMSIRIKUL
Sirindhorn International Institute of Technology,
Thammasat University, Thailand
somnuk@siit.tu.ac.th
ABSTRACTThis paper introduces some problems on deterioration of concrete
structures in Thailand and some concepts on their future solutions. A
survey of damages due to durability problems of some structures in thecentral and eastern parts of Thailand was carried out to explore the level ofseverity of the problem. It could be summarized that problems occurred invarious states of the works i.e. from design, material selection, construction
and maintenance. Some examples of problems in each state are illustrated.
Solutions were offered in two categories i.e. that for new construction andthat for the existing structures. For new construction, the performancebased analysis and design taking into account the service life of thestructures is proposed. For the existing structures, good protection, repair,strengthening shall be carried out.
1.0 INTRODUCTION
The current practices for design and construction of concrete
structures in Thailand are based mainly on short-term properties of concrete.
Civil engineers concern much only on a few properties of the concrete suchas workability and mechanical properties like strength and Young’s
modulus, etc. at the design age which is usually 28 days. Unfortunately,
those considered properties are just a few of the overall properties ofconcrete when considering the whole service life of the concrete. There arestill many properties that should be considered especially those in long-term
state such as durability properties. The current development plan of thecurrent Thai government has set ground for enormous investment on
infrastructures especially in the transportation and communication sectors.
It is an urgent task for Thailand to change the way of practice from thementioned strength concept to be a more rational design taking into accountoverall properties throughout service life of the structures. In addition, withmany infrastructures constructed within the past decades, already there is
now a huge stock of infrastructures that requires proper maintenanceprograms. Figure 1 shows the distribution and trend of annual total
construction budget of a major public organization in Thailand in the past
decade from 1996 to 2002 as an example to demonstrate the criticalsituation in the near future.
The figure shows that the ratio of
maintenance/total construction budget has surged from 45% in 1996 to 65%
in 2002 while the total budget tends to be constant or even decreased. It is

177
305

October 2004, Agra, Indiathen expected that this organization will have financial difficulty to expand
new infrastructures and may even have difficulty to properly maintain theexisting infrastructures. This situation is similar for all public organizations
but only with different seriousness. The situations in many countries are notmuch different.
This paper introduces the results of surveys on current situation of
concrete structures in some parts of Thailand, indicating various problems.
Many evidences deterioration with various degrees from light to serious
were observed. The deterioration was caused by insufficient knowledge andattention in various steps of the practices starting from analysis and design,material selection, construction and maintenance. It is necessary to plan fora solution to this problem for the sake of economic and safety.
Budget (Million Baht)

125000100000
75000
50000
25000
0

'96 '97 '98 '99 '00 '01 '02

MaintenanceTotal Construction

Figure 1: Budget situation of a major public organization in Thailand
2.0 SURVEYS ON DETERIORATION OF CONCRETESTRUCTURES SHOWING DETERIORATION PROBLEMS
Surveys on situation of deterioration of some concrete structures inThailand have been conducted since 1997 with the aim of gathering data on
the types and degree of deterioration of the surveyed structures [1, 2, 3].
Two regions were selected for the survey namely central region (including
Bangkok) and eastern region of Thailand. The two regions have different
types of environment. The main difference of the two regions is on theexisting of chloride attack. Eastern part of Thailand is the region closed tosea and is subjecting to attack by salts. Figure 2 shows the map of Thailand
and the survey area denoted by the name of the provinces in the map.
According to this survey, the following summary can be drawn:

178

There were various causes of deterioration including those due
to load and due to environmental attack such as drying
shrinkage, thermal crack, sulfate attack, acid attack, alkali
aggregate reaction, carbonation, chloride attack, etc., and thoseoccurs during construction like plastic shrinkage, bleeding andsettlement, etc.

New Technologies for Urban Safety of Mega Cities in Asia
306

ICUS Report 6

 Most damages were visible in form of steel corrosion.
Damages due to steel corrosion are much more serious in theeastern part than in the center of Thailand. The steel corrosion
problems in the eastern part are due to chloride attack but
those found in Bangkok area are mostly due to carbonation.
 Many of the steel corrosion problems were due to poor
construction such as insufficient concrete cover orhoneycombing, etc.
 Very few maintenance programs are in action for thosestructures.
 The selection of raw materials and mix proportion of concrete
was only based on a few performances such as strength andworkability. The concept of selecting proper materials andproper mix proportion for different environment was notpracticed in the past but has been just started in these few years.

1RUWK

Figure 2: Map of Thailand showing the surveyed regions
The problems in all stages of practice can be observed, starting fromstage of analysis and design, raw materials selection and mix proportioning,
construction and maintenance. Figures 3 to 8 show some examples of the
problem in each stage.

Durability Design for Concrete Structures for Urban Safety in Thailand
307

179

October 2004, Agra, India



Crack

Figure 3: Crack on a roof slab of a stadium (Analysis and design problem)a) Cracks due to AARb) Sulfate and acid attack in sewer water

Figure 4: Material selection problem



Figure 5: Severe honeycombing due to segregation (Problem of concrete
mix proportion)

180

New Technologies for Urban Safety of Mega Cities in Asia
308

ICUS Report 6



Figure 6: Plastic shrinkage (left) and plastic settlement cracking (centerand right) showing construction problems

Figure 7: Steel corrosion due to insufficient concrete cover under a bridge(left) and in a building (right) (Construction problem)

Figure 8: Concrete spalling due to carbonation induced steel corrosion in
Bangkok area (left) and chloride induced corrosion in easternpart of Thailand (right) (Maintenance problem)
3.0 SOLUTIONSThe solution to this problem can be implemented by considering 2
measures, first for new structures to be constructed from now on and second
for the existing structures that had been built. For new structures, thefollowing measures are to be implemented:

Durability Design for Concrete Structures for Urban Safety in Thailand
309

181

October 2004, Agra, India

A better analysis and design considering not only short term but
long term performances of the structures (Performance based
analysis and design). Design code shall be modified in thementioned way. At present, the design regulation is modified by
the Department of Public Work and Urban Planning to incorporate
the durability into the design.

Selecting proper raw materials and mix proportion of concrete foreach type of structure and different types of environment. The
concept of proper concrete for each structure type and eachenvironment must be seriously considered. Shown in Figure 9 aresome computer program for analysis and design of concrete mix
proportion by considering requirements of concrete performancessuch as workability, strength, temperature rise, carbonation andchloride content of the concrete.

a) Slump and strength designb) Analysis of temperaturec) Analysis of carbonation depthd) Analysis of chloride profile

Figure 9: Examples of performance based computer software for analysis
and design of concrete mix proportion (An effort to cope withproblems on material)182

A much more seriousness in quality control and quality assuranceof construction must be practiced. The Engineering of Thailand
and Thai Concrete Association are now modifying their codes of

New Technologies for Urban Safety of Mega Cities in Asia
310

ICUS Report 6

practice for construction and to conduct seminar courses for thepractice engineers.
The existing of good plan of protection and maintenance which
will prevent intensive repair or strengthening in the future has tobe considered from the beginning of the project.

For the already built structures, there is an urgent need to create a
database indicating the cause and degree of deterioration of the existing
structures in order to conduct a proper protection, maintenance, repair,strengthening or reconstruction program for each case. There is a strong
need to publish higher level of appropriately advanced codes and standardsof practice and to provide more education in order to get the problems
solved. The Thai Concrete Association is now drafting various codes andguideline for maintenance of concrete structures and preparing for seminarand training using the drafted codes and guidelines in the near future. These
will include the code and guideline for selecting repair materials and repair
methods that will prevent the wrong practice as those shown in Figure 10.

Figure 10: Cracking in the patching material due to incompatible shrinkage
property (left) showing improper selection of repair material.
Improper sequence of construction causing epoxy to adhere on
the steel reinforcement (right) showing low quality handling.
4.0 CONCLUDING REMARKS
Based on a survey on the deterioration situation of some concrete
structures in the central and eastern parts of Thailand, it was found that eventhough most of those structures were constructed just in the past decade,there were many problems regarding deterioration which would lead tofuture burden or even accident unless a proper plan for maintenance, repair
and rehabilitation is realized. Not only the existing damaged structures, butalso the newly constructed ones and those to be constructed must be
considered. A proper protective maintenance plan for newly and stillundamaged structures and proper practices in analysis, design, materials
selection, construction and maintenance plan for those to be constructedmust be available.

Durability Design for Concrete Structures for Urban Safety in Thailand
311

183

October 2004, Agra, India

ACKNOWLEDGEMENTS
A part of the survey was partially funded by the International Centerfor Urban Safety of the University of Tokyo where the author would like toacknowledge for the support. The author would like to also express
appreciation to Dr. Toshiharu Kishi of the University of Tokyo, former
seconded faculty member to Asian Institute of Technology and many
graduate and undergraduate students from Sirindhorn International Instituteof Technology and Asian Institute of Technology for their contributions tothe survey.
REFERENCES
Tangtermsirikul, S., 2003. Information Acquisition and Structural Health
Monitoring of Bridges in Bangkok. A report submitted to theInternational Center for Urban Safety, the University of Tokyo.
Tangtermsirikul, S., et.al., 2000. Durability of Concrete. Engineering
Institute of Thailand, ISBN 978-974-87684-5-7, Thailand.
Wongtanakitcharoen, T., 1999. A Study of Deterioration of RC Structures inCentral and Seaside Areas of Thailand. A Master thesis No. ST-99-32,
Asian Institute of Technology, Thailand.

184

New Technologies for Urban Safety of Mega Cities in Asia
312

AN EXPERIMENTAL STUDY ON COMPLEX
DETERIORATION OF CONCRETE
USING GROUND GRANULATEDBLAST-FURNACE SLAGTOSHINOBU YAMAGUCHI1, KOJI TAKEWAKA1,
JUNICHI MATSUMOTO1 AND YOSHIKAZU AKIRA2
1
Department of Ocean Civil Engineering, Kagoshima University, Japan
2
Port and Airport Research Institute, Japan
yamaguch@oce.kagoshima-u.ac.jp


ABSTRACT
Recently, a complex deterioration due to plural deterioration factors
has posed one of serious problems in RC structures. The effect on complex
deterioration is not clear, especially as for concrete using groundgranulated blast-furnace slag which, in Japan, commonly applied in coastal
environment.
In this study, the experimental examinations on the deterioration due
to each/both salt attack and neutralization were carried out using mortar
with substitution ratios of the ground granulated blast-furnace slag by
accelerated tests. As the results, by using GGBS, though neutralization
depth increases, penetration of chloride ion and corrosion properties of rebar can be improve. However, to use GGBS as admixture of concrete,content of GGBS and initial curing time must be considered.
1.0 INTRODUCTION
Recently, a complex deterioration due to plural deterioration factors
has posed one of serious problems in RC structures (Saeki, T., 2002). The
effect on complex deterioration is not clear, especially as for concrete using
ground granulated blast-furnace slag which, in Japan, commonly applied incoastal environment. The reasons to use GGBS are to inhibit alkaliaggregate reaction, to reduce hydration heat, to improve diffusivity ofchloride ion, and so on (Matsushita, H.,2003, Kokubu, k.,1988).
In this study, the experimental examinations on the deterioration due
to each/both salt attack and neutralization were carried out using mortar
with substitution ratios of the slag by accelerated tests. Corrosion areas of
re-bar were also measured to examine its effectiveness as an index for the
corrosion under complex deteriorative environment.

185
313

October 2004, Agra, India
2.0 EXPERIMENTAL PROGRAM
2.1 Specimens
Properties of used materials, ordinary portland cement, river sand and
GGBFS, are shown in Table 1. Mix proportions for mortal specimens areshown in Table 2.The shape of specimen is shown in Figure 1. Cylindricalmortar specimens with a size of 10 cm in diameter and 10 cm in height,
having a re-bar embedded with a cover depth of 3 cm were prepared. The
side and bottom of each specimen was coated by epoxy resin. To examine
the effect of initial curing time before exposure, three periods, 7, 28, and 91
days, were carried out for each mix proportion.
Table 1: Properties of materials
Materials

Density

Specific surface
area / F.M.

Cl (%)

Ordinary portland cement

3.16 g/cm3

3290 cm2/g

0.009

Ground granulated blast furnace slag

2.90 g/cm3

4010 cm2/g

0.002

River sand2.63 g/cm3

F.M. : 2.68



Table 2: Mix proportions
Series50-S0050-S5050-S7070-S0070-S5070-S70W/B (%)
50
50
50
70
70
70

Unit weight (kg/m3)

past
GGBS/B
volume (%)
(%)
45
45
45
41
41
41

W

B

GGBS

Ｓ

0
275
550
0
1447
50
271
271
271
1447
70
269
161
377
1447
0
282
403
0
1552
50
278
199
199
1552
70
277
119
277
1552 
* Mortar flow: 200 mm for every mix proportion

D10(SD35)
100

30

100



Epoxy





Figure 1: Size of specimen (mm)186

New Technologies for Urban Safety of Mega Cities in Asia
314

ICUS Report 6


2.2 Accelerated condition
In the experiment, 3 types of accelerated test were performed,
assuming deteriorations, such as salt attach, neutralization, and complex ofboth. Table 3 shows each accelerated conditions. Setting 7 days in eachaccelerated conditions as 1 cycle, chloride ion content, neutralization depth,
corroded area of re-bar were measured every 10 cycles. Picture 1 shows theacceleration system originally developed by authors (Akira, Y.,2001).
Table 3: Cycle condition for each accelerated test
Deterioration

Immersion (3.5days)

Drying (3.5days)

Salt attack

5% NaCl solusion

Normal Air

Nutralization

Distilled water

CO2 5%

Complex

5% NaCl solusion

CO2 5%

3.0 RESULTS AND DISCUSSION
3.1 Neutralization depth
Figure 2 shows neutralization depth of each type of specimen, after 10cycles of complex deterioration test. As previously reported, neutralization
depth increases with increasing GGBS content and water binder ratio, anddecreasing initial curing time. However, this unbeneficial characteristic ofconcrete and mortar using BBGS can be partly reduced in complex
deterioration as shown in Figure 3.

Neutralization depth (mm)

12
10
8
6

Initial curing time

10cycles7 days28 days
91 days420
50-S0050-S5050-S7070-S70Figure 2: Neutralization depth (complex)

A Experimental Study on Complex Deterioration of Concrete using Ground Granulated Blast-furnace Slag
315

187

October 2004, Agra, India

Neutralization depth (mm) )
12Initial curing time: 28 days

10

10cyclesNutralization
8

Complex64
20
70-S0070-S5070-S70Figure 3: Neutralization depth in different deterioration tests
3.2 Penetration of chloride ion

3

Chloride content (kg/m)3)( Kg/mFigure 4 and 5 show the diffusion properties of each type of specimen
in complex deterioration test, and Figure 6 shows the comparison ofchloride diffusion coefficients obtained from the results of both single andcomplex deterioration tests. However, the beneficial characteristic of BBGS
reduces due to the effect of neutralization, the great improvement inresistance against the penetration of chloride ion due to the GGBS can be
still observed in both water binder ratio.

30

40cycles25

Initial curing time: 28 days

20

50-S0015

50-S5050-S70

10
5
0
0

1
2
3
4
Depth from the surface (cm)5

Figure 4: Chloride content in specimen (complex, W/B 50%)

188

New Technologies for Urban Safety of Mega Cities in Asia
316

ICUS Report 6

3

Chloride content (kg/m) 3))( Kg/m
30

40cycles25

Initial curing time: 28 days

70-S0020

70-S5015

70-S70

10
5
0
0

1
2
3
4
Depth from the surface (cm)5

Figure 5: Chloride content in specimen (complex, W/B 70%)

12

Initial curing time: 28 days

10

10cycles

8

Salt Attack
complex64
20
70-S0070-S5070-S70Figure 6: Chloride diffusion coefficient in different deterioration tests
3.3 Corrosion properties
Figure 7, 8, 9, and 10 show the corrosion area of re-bar in each typeof specimen, during complex deterioration test. Figure 11 shows thecomparison of corrosion area of re-bar between salt attack deterioration andcomplex deterioration. From these figures, it is found that corrosion area ofthe re-bar increases with increasing water binder ratio and GGBS content.
Up to 50% GGBS conctent, corrosion area can be reduced by using GGBS.
However, the most important point is the conflicting phenomenon
between chloride content and corrosion area in high GGBS conctent
specimen. That is to say, in spite of high resistance against chloride
penetration which GGBS mortar has as shown Figure 4 and 5, re-bar insideof high GGBS mortar, such as 70% GGBS content can be corroded even thevery little chloride content. For the phenomenon, initial curing time is also

A Experimental Study on Complex Deterioration of Concrete using Ground Granulated Blast-furnace Slag
317

189

October 2004, Agra, Indiavery essential parameter to maintain the durability of GGBS concrete.
Therefore to use GGBS concrete for the complex deterioration
environments concerning to neutralization and salt attack, the GGBS
content and initial curing are should be considered carefully.

Corrosion area (%)

30
Initial curing time25

7 days28 days
91 days
28 days ( 50-S00 )

20
15
10

W/B : 50%
GGBS: 50%

5
0
0

10

20

30

40

CyclesFigure 7: Corrosion area of re-bar (complex, W/B 50%, GGBS 50%)

Corrosion area (%)

30
Initial curing time25

7 days28 days
91 days
28 days ( 50-S00 )20
15

W/B : 50%
GGBS: 70%

10
5
0
0

10

20

30

40

CyclesFigure 8: Corrosion area of re-bar (complex, W/B 50%, GGBS 70%)

190

New Technologies for Urban Safety of Mega Cities in Asia
318

ICUS Report 6

Corrosion area (%)

30
W/B : 70%
GGBS: 50%

7 days28 days
91 days
28 days ( 70-S00 )

25
20
15
10
5
0
0

10

20

30

40

CyclesFigure 9: Corrosion area of re-bar (complex, W/B 70%, GGBS 50%)

Corrosion area (%)

30
7 days Initial curing time
28 days
91 days
28 days ( 70-S00 )

25
20
15
10

W/B : 70%
GGBS: 70%

5
0
0

10

20

30

40

CyclesFigure 10: Corrosion area of re-bar (complex, W/B 70%, GGBS 50%)
20
Corrosion area (%)

30cycles15

Initial curing time 28 days

Salt attack
Complex1050
70-S0070-S5070-S70Figure 11: Corrosion area of re-bar between different deteriorations

A Experimental Study on Complex Deterioration of Concrete using Ground Granulated Blast-furnace Slag
319

191

October 2004, Agra, India
4.0 CONCLUSIONSIn this study, experimental examinations were performed in order tograsp the complex deterioration properties of concrete using GGBS (groundgranulated blast-furnace slag), especially for the complex between salt
attack and neutralization. As the results, it is found that an interactive
deterioration of concrete can be occurred in the complex deterioration
environment.
By using GGBS, though neutralization depth increases, penetrationof chloride ion and corrosion properties of re-bar can be improve. However,to use GGBS as admixture of concrete, content of GGBS and initial curing
time must be considered.
REFERENCES
Saeki, T., Ueki, S., and Shima, T., 2002. A model for predicting thedeterioration process of concrete due to the compound interaction ofsalt damage and carbonation, Journal of material. Concrete structuresand pavements, Vol.697, No.54, 131-142.
Matsushita, H., Harada, T., Soeda, M., Ryu, R., and Yoshitake, T., 2003.
Durability design and thermal cracking control of concrete piers ofshin-kita-kyushu airport bridge. Journal of construction management
and engineering, Vol.728, VI-58, 79-92.
Kokubu, K., Murata, Y., Takahashi, S., and Anzai, H., 1988. Studies on
adiabatic temperature rise and hydration of portland cement concrete
incorporating ground granulated blast furnace slag. Journal ofmaterials, concrete structures and pavements, Vol.396, V-9, 39-48.
Akira, Y., Takewaka, K., Sato, T., and Yamaguchi, T., 2001. Experimental
study on deterioration of concrete structure due to acid rain. First
international structural engineering and construction conference.

192

New Technologies for Urban Safety of Mega Cities in Asia
320

CASE STUDY OF THE REPAIR OF A
MAJOR BRIDGE AND SOME THOUGHTSON REPAIR MATERIALSMANJREKAR S. K.
SSCPL, Mumbai. India
sscpl1@bom5.vsnl.net.in
ABSTRACTThe paper discusses repair and rehabilitation of a major road overbridge connecting eastern and western suburbs of Andheri, Mumbai. Whilethe case study is described, the author dwells upon some of the important
aspects involved in selection of appropriate materials and methodologies ofrepair / rehabilitation.
1.0 INTRODUCTION
Rehabilitation of reinforced concrete (RC) bridges prematurely orotherwise damaged, continue to be a major problem throughout India. The
problem is more serious in the coastal areas and is aggravated further in thehighly polluted city like Mumbai. Many a bridge needs major repairs. Inview of the need to maintain continuous traffic flow on the bridge the repair
methodology assumes great importance. A case in point is the repair to the
Gopalkrishna Gokhale (GKG) Bridge, connecting S. V. Road and theWestern Express Highway in a suburb of Mumbai.
Major rehabilitation work of the western approach of this bridge has
been just concluded. It was carried out in very trying conditions ofcontinuous traffic flow matched with the serious damage taken place over
the years. This paper is an effort to understand the nature of damage andthen the logical solution to repairs based on the latest understanding of thematerials, particularly polymers and polymer-modified mortars/ concretes.
An attempt is also made to explain the mechanisms involved. This is withthe expectation that this case study which is possibly first example of its
type in terms of the expanse of the job and large quantities of materials
required can be a guidance for posterity to assess and carry out such bridge
repairs in the future.
2.0 DETAILS OF THE CASE STUDY
2.1 Salient features of the bridge
The salient features of the GKG Bridge are as below:
1. Year of construction
2. Width of bridge

:
:

1969
27.45 m193
321

October 2004, Agra, India

3. Superstructure
On railway track:
Structural steel
On approaches:
RCC T-beam and slab
(Total length 160m: 100 m on the western side and 60m on theeastern side.)
4. Substructure:
12 RC columns(the area below RC approach is enclosed and used as offices)
5. No. of girders per span:12
6. Thickness of deck Slab:
250 mm
7. Bearings:
Roller and rocker-roller typesteel bearings
8. Foundation:open
9. Total length of approaches :Eastern side- 240 m
Western side- 220 m
2.2 Nature of damage
Detailed visual inspection revealed the following types of damage:
Heavy and continuous leakages
Development of cracks in deck, girders and columns
Chunk of concrete mass fell off from western approach deck
exposing the deck reinforcement steel
Parapet walls cracked extensively.
Non-destructive testing was carried out involving ultrasonic pulse
velocity tests, carbonation test, half-cell potential mapping, determination of
pH of concrete and chloride content estimation, etc. Based on the visualobservations and results of non-destructive testing, consultants worked out adetailed procedure for the repairs which constituted following specifications.
Support the RC members by steel props and spans appropriately,
depending upon loading conditions and extent of damage of themembers to be repaired.
Expose the member by means of chisel and hammer. Remove theloose concrete beyond the reinforcement.
Remove loose rust from reinforcement by means of tacha and wirebrush (mechanical/manually).
Apply phosphate-based rustconverter- RUSTICIDE capable of removing corrosion products
to the reinforcement by brush or cotton waste. After 24 hours
wash the reinforcement by clean water jet.
Providing and applying slurry of 1 part of specially formulated
alkaline acrylic-based polymeric solution - POLYALKFIXOPRIME with 1.5 part of fresh cement and mix the solution
by means of stirrer and apply it on the reinforcement by paintbrush. This will act as protective coating on the reinforcement.
After 24 hours apply similar second coat of such slurry. Make
sure no area is left uncovered.
Providing and applying bond coat of single-coat acrylic copolymeric admixture - POLYALK EP and cement in 1:1

194

New Technologies for Urban Safety of Mega Cities in Asia
322

ICUS Report 6

proportion to RC members and applying polymer-modified mortar
to build up the thickness upto 10 mm.
Repairing of damaged RC member by single coat co-polymericmortar in 1:5:15 (acrylic co-polymer (POLYALK EP): cement:
Quartz sand) proportion and required proportion of water.
Curing the same by spray pump after 24 hours.
This paper lays emphasis on the material science dealing with theproperties, behavior and mechanisms of various repair materials / polymers
used in the above work. For various steps involved in the work
corresponding cross-references are also provided for better understanding.
3.0 REPAIR: SOME THOUGHTS
For effectiveness of any repair the following points need thoroughconsideration from material properties and compatibility point of views,
besides the important considerations of structural parameters:
Ascertaining the extent of corrosion and carbonation
Near total removal of corrosions products from the steel.
Application of a corrosion resistant barrier film on thereinforcement (such film should inhibit further corrosion)
Application of a useful bond coat which assures good bonding.
Rendering a strong, passive carbonation resistant polymer
modified / polymer concrete cover of proper generics, wherevernecessary.
Applying protective seal coat on the entire surface to guard against
any aggressive chemical attack.
Carbonation is one of the principle causes of corrosion and it brings
about various physical changes in the quality of concrete. However, itaffects the alkalinity of the concrete by bringing it down considerably.
Generally, the pH of good concrete which is in the vicinity of 12.5 to 13
comes down to around 9. This loss in pH causes the reinforcing steel to besusceptible to corrosion. The carbonation plane moves into the concrete
from the outer surface as a result of external attack and it is dependent upon
the moisture content of the concrete. This plane moves rapidly whenrelative humidity is between 50 to 70 percent1. One can find out the depthof carbonation from a formula d= kc t where, d= the depth of the
carbonation reaction plane in mm, after time t, years. Coefficient ofcarbonation kc is related to the permeability of the concrete, the amount ofavailable free time, relative humidity1 and the carbon dioxide (other relatedgases in case of polluted environments) content of the given environment.
As reported2 in the present case study, the carbonation attack was seen
to be upto 70 mm depth which was associated with highly undesirable low
pH in the range of 5 to 8.0. Half cell readings also were fairly negative inthe range of - 450 to - 600 mv. These data corroborated well with theCase Study of the Repair of a Major Bridge and Some Thoughts on Repair Materials
323

195

October 2004, Agra, India

physical state of the bridge. Thus, ascertaining the extent of corrosion andcarbonation proved to be very useful first step in the sequence of repairs.
The next step consisted of the process of removal of diseased/ loose
concrete and removal of corrosion products from the steel and preparing thesurface for further applications. It needs to be mentioned here that
howsoever effective the materials are, the basic surface treatment plays very
important role in the efficacy of the repair operation. In addition, it is very
important to see that the surrounding good concrete is not damaged. In thiscase chipping was done by hammers, which is most widespread method of
concrete removal if the deterioration is deeper than 15 mm or more. ACI
committee 5463 also stresses on proper selection of chipping tools, which
will avoid the damage of surrounding concrete. However in recent years theintroduction of the water jet technique (hydro demolition or hydro jetting orhydro blasting) has changed the prevalent method of concrete removal4.
Besides high efficiency several other advantages listed below add to thesuccess of this method:A rough and clean surface made available.
No micro cracks are introduced into the remaining concrete.
The reinforcement is undamaged and cleaned from rust, andOnly bad concrete is removed leaving the good concrete intact.
In fact, some comparative studies also have been made on the interface
strength of a repaired matrix between sand blasted surface, mechanicallychipped surface and the water-jetted surface. In water jetted surface,maximum bond strength was shown followed by mechanically chipped andthe sand blasted surface showed the least bond. In the present work it washowever decided to adopt the chipping method, using chipping tools whichfits in the recommendations of ACI Committee 546.
The next important step was to ensure that the corrosion products on
the steel are removed effectively. For this, it is reported that the mechanicalmeans prove quite inadequate. Hence, it was correct to use the chemicalrust remover-cum-converter material. The application of this material does
not reduce the section of steel (like in sand blasting) after having removed
the loose oxidation scales. It, in fact, consolidates the left over section. This
treatment also helps in resisting the corrosion to an extent, though,subsequent process of pacifying the steel is very essential.
Neither chemical cleaning nor rust converting processes are permanentrelief from corrosion. Hence, a protective barrier film is generally appliedon the treated steel. One of the options is to apply liquid epoxy on the bars
which on setting becomes almost plastic-like, resulting in substantial loss ofbond with subsequently laid concrete. It is reported that as much as 40
percent bond is lost5. In order to overcome this bond loss fine quartz sand issprinkled on the wet epoxy on many occasions. In addition, this treatment
being only a barrier film does not do anything so as to create non corrodible
conditions around the steel. However, despite these drawbacks epoxy

196

New Technologies for Urban Safety of Mega Cities in Asia
324

ICUS Report 6

treatment for bars has been found to be more effective than any othercoating treatment like zinc chromate priming6, etc.
Table 1: Indicative properties of the polymers
Sr. No.

Properties

1

Adhesion to concrete, N/mm22

Adhesion to steel, N/mm2

3

Tensile strength, N/mm2

45Compressive strength, N/mm2
Flexural strength, N/mm2

6Effects of chemicals on dry flexuralstrength after six months immersion,
N/mm2
Untreated
10%potassium hydroxide
10% magnesium sulphate
5% lactic acid
5% hydrochloric acid
Effects of extremes of temperature
N/mm2
untreated
after 6 frees/ thaw cycles at 18°C
( in 10% brine)
after 1 year at 70°C
Adhesion to concrete (dry) , N/mm2
untreated
after 6 months at 70°C
Shrinkage to concrete (dry) , N/mm2
water-cement ratio
percent shrinkage
Water penetration, g/ m2/24 hours
Water penetration with Revinex 29Y
40 in mortar, Kg/ m2 /24 hours

7

8
9
10
11

Polymer / Cement ratio(on Wt/Wt basis)
0
0.2
0.4
Dry
Wet
Wet
Dry
Wet
Dry
Wet
Dry
Dry
Wet

0.07
0.03
0.00
0.0
0.0
3.0
1.8
56.0
7.1
5.8

2.0
1.0
1.4
2.0
6.0

3.4
1.4
2.1
1.6
1.3
4.3
3.9

50.0
10.6
9.6

7.2
6.1
4.3
5.9
0.0

13.2
12.3
13.2
8.0
2.2

7.1
0.0

10.6
10.4

5.2

14.3

0.1
0.0

3.4
2.6

0.40
0.07
46.9

0.34
0.02
38.1

0.30
0.01
1.9

100.0

35.0

0.0

3.1 Need of a bond coat
In order to overcome the above mentioned shortcomings, a slurry ofwater based polymer emulsions and cement is applied on steel. This mixture

Case Study of the Repair of a Major Bridge and Some Thoughts on Repair Materials
325

197

October 2004, Agra, India

being highly alkaline in nature keeps the environment around steel in an
alkaline state. This situation helps greatly in maintaining a passive, γ-Fe2O3
film on the steel, thereby preventing corrosion7. Besides, this film being
cement based, it is a compatible material with concrete and does not resultin any loss of bond strength making the structural engineer’s work easy.
Moreover, the film is quite tough as well as flexible. In addition, being a
one-pack polymer system, hardening of unused material or setting of thematerial due to delayed use, etc is more or less eliminated. For reasonsmentioned earlier, pure acrylates, modified acrylates, modified styrenebutadiene rubber (SBR), etc are used as concrete modifiers, preference
being in that order too. These tailor-made formulations are easily available.
For the current job the material used was acrylate-based polymeric solution
which is tailor-made to protect γ-Fe2O3 film that is to prevent further
corrosion for long time to come. As a matter of fact, this material isspecially formulated to withstand even the stress corrosion when used withsuitably-formulated cementitious and supplementary cementitious materials8.
This step is one of “the important” steps to avoid further deterioration as
well as to enhance the life of the repaired system.
Earlier we have discussed the mechanism of improving the bondstrength at the stage of pretreatment of the method of removal of diseased
concrete. In addition to this, in terms of additional and assured bonding
methods one must consider the ‘Swedish Regulations for Concrete
Structures” which do not permit shear transfer at interfaces of composite
concrete structures. European and American concrete codes prescribe
comparatively low values for the permissible shear stress at the interfaces
like 0.22 to 0.62 N/mm2 (dependent on characteristic compressive concrete
strength9) and 0.55 N/mm2, respectively. Consequently, reinforcement
crossing the interface is needed as soon as the applied design shear stressexceeds these small values. This means the shear capacity in composite
repairs can be provided by shear connectors or dowels at very closeintervals which on a large area could prove very impractical and expensive.
That is why to ensure further adhesion between two phases, namely,
between the original concrete and the new repair material, a polymer
cementitious adhesive bonding coat is considered essential.
In several cases, where traditional repairs are executed by replasteringor mere concrete jacketing, or even guniting, it is often seen that the newconcrete / mortar mass separates from the old concrete. This obviously
happens due to dissimilar behavior patterns of the old, already set concreteand the subsequent new concrete or mortar, which is undergoing stresses
and strains while stiffening, mainly due to shrinkage. To an extent thisdrawback is nullified by using steel wire mesh. Although the wire meshhelps to distribute shrinkage stresses evenly it may introduce additional
corrosion problems. To overcome this, galvanized wire mesh is used, but
this may prove to be costly. Hence, years of experience has taught the
repair specialists to use a bond coat which ensures mechanical bond
between old and new concrete. However, sometimes inappropriate quantity/ quality of bonding coat together with the shortcomings in workmanshipresults in an undesirable performance.

198

New Technologies for Urban Safety of Mega Cities in Asia
326

ICUS Report 6

Liquid epoxy in tacky conditions is found to be an excellent bonding
coat. However, sometimes if a large area is to be concreted, for example,
jacketing of all four sides of the column, or when due to the negligence on
the part of workmen, the time lag between application of the epoxy bondcoat and subsequent placement of new concrete increases, it results in theepoxy being partially or fully set and consequently it acts as debonding
agent rather than a bonding agent. In such cases, separation cracks at theinterface can be seen. This is not because of the failure of the material but
due to the two-pack epoxy not being utilized properly. Hence, use of userfriendly material is necessary and this should preferably a one-pack system.
Bonding polymers, which are based on polymer latexes, when used alongwith cement, give equally excellent adhesion both to old concrete as well as
the new one. There is substantial reduction in cost too and the one packnature of the polymer keeps the tackiness of the surface for a long time. It
also helps to keep the conditions around the exposed steel and exposed
concrete generally alkaline, thereby preventing corrosion of steel andcarbonation of the adjacent concrete. Those latexes which are mentioned
earlier for steel protection are good for bonding purposes too.
In the present case study we have used a bonding coat of acrylate
based co-polymeric solution and cement in 1:1 proportion (part by weight)
as a slurry. Such polymeric materials are reported to show added bonding
to concrete and steel which is approximately thirty times more in concrete toconcrete and almost 100 times more in case of steel and concrete10. Such abonding coat can effectively replace the use of dowels at very closeintervals.
3.2 Polymer modified mortar/ concrete
Providing a new cover to a repairable structure should be done only
wherever necessary and the temptation to expose the entire surface – even if
a part of it is unaffected strong concrete, should be avoided. Judicious
removal of diseased concrete is therefore essential. If the replacement isdone by unmodified concrete, it can deteriorate due to carbonation andchemical attacks.
The most important factor encountered in selecting methods andmaterials for repair is the compatibility of existing concrete and newmaterials. Many materials change volume as they initially set, andpractically all of them change volume with temperature and moisturechanges. Tensile stresses are induced in one material and compressive
stresses in the other, causing a substantial shear at the interface. Identical
patterns of stress will result from the differential shrinkage and different
moduli of elasticity11.
In the initial stages of advent of polymers for repairs, the only reliablematerial used for making up the lost concrete as epoxy. It is a very strong
material and can easily give compressive strength of 80 to 100 N/mm2 andhigh tensile strength of 20 to 30 N/mm2. In addition, epoxy mortars whichfall under the category of polymer mortars are not affected by chemical

Case Study of the Repair of a Major Bridge and Some Thoughts on Repair Materials
327

199

October 2004, Agra, India

attack or carbonation. However, the following few points have madeengineers and materials scientists ponder over alternatives to this system:
Most of the reinforced concrete members to be repaired are having
concrete strengths between 20 and 25 N/mm2. Hence, how correct
is it to introduce in it intermittent pockets of very high-strengthmortar?
The cost of epoxy repair can be high, particularly if large areas areto be rehabilitated.
If faulty application is done, basically due to two-pack nature of
epoxy and negligence on the part of the labourers (due to its user
unfriendly character), bonding and integrity of mortar suffers
resulting into undesirable behavior of the concrete.
Epoxy mortars are found to be susceptible to fires or fire-prone
areas, wherein the mortar itself catches fire readily. This not only
leads to loss of earlier repairs but the fire also increases.
If user-friendly, one-pack polymer cementitious mortar is used,such mortar will be more compatible with the existing reinforced
concrete members and it will have good properties like chemical
resistance, carbonation resistance etc.
Preparation of cementitious polymer mortar is easy forconstruction workers, since it is a plain cement mortar in which thepolymer is to be simply mixed. This does not require any
specialized training and hence the problems of poor workmanshipcan be minimised.
Due to above points, the trend is shifting in favour of polymer
modified cementitious mortars which have improved chemical and physicalproperties as compared to ordinary cement /concrete mortar. In addition to
above reported properties, studies of comparative photomicrographs haveshown that the addition of polymer emulsions to concrete results in bondingof the latex to the aggregates and helps in bridging the cracks as they form.
As a result, the polymer relives the internal macro stresses, retards theformation and enlargements of cracks and increases the concrete’s overall
strength. Moreover, as the voids and cracks are bridged bay the polymer, it
results in substantially reducing the penetration of moisture and corrosion
chemicals. The indicative properties of the polymers used in these mortars
are given in Table 110. The cost of these mortars is approximately 33
percent of the cost of epoxy mortar. In addition, the polymer mortar coveris of the order of 10 to 15 mm in thickness above steel. Such thickness itself
can adequately take care of further chemical attack or subsequentcarbonation. Remaining part of the cover can be simply finished with wellcontrolled plain cement / concrete mortar to get proper level. Suchjudicious use of polymers can further bring down the cost of rehabilitation
without sacrificing on performance. In many countries such mortars findlarge application in repair of bridge decks where the cost of repairs due tocorrosion would otherwise be colossal.

200

New Technologies for Urban Safety of Mega Cities in Asia
328

ICUS Report 6

3.3 Surface protection treatment
The final step in the rehabilitation project is the application of thepenetrating sealer to entire surface including the repaired concrete parts.
This helps to minimize the moisture and chloride penetration and related
continuous environmental attack. Repairs are carried out on patch-workbasis and these patches are repaired with polymer concrete/mortars or
polymer modified mortars/concretes. Obviously at these repaired patches
environmental attack or carbonation attacks are not effective, though theadjacent area may get affected. Hence, to protect the entire area fromattacks and to avoid subsequently repair expenses, application of the surface
coating becomes imperative. Generally, these protective seal coats are
suitably pigmented so that besides protection, aesthetics of the structure canalso be taken care of simultaneously. Various coatings like polyurethane,epoxy, alkyds, chlorinated rubbers, acrylic emulsions can be used for thispurpose. However, selection is done keeping following points in mind:
Adhesion to the surface
Compatibility with alkalinity of concrete
Breathing capacity at the same time the coating should be
impermeable enoughResistance to aggressive attacks
Expected longevity of the treatment
Capacity to absorb irregularities of the surface like slightdampness or imperfect cleaning of the surface.
Ease in application and availability of color shades.
In the case study reported here, specially formulated material suiting
above requirements, an acryl ate based copolymer formulation POLYALK WP was mixed into colored cement to form a water resistantcoating to avoid any ingress of moisture / water in the concrete.
4.0 PARTICIPANTS IN THE PROJECT
ClientMumbaiConsultants:

Municipal Corporation of Greater:

Contractors
Supplier of Construction::

S. J. Group, Mumbai, andStructural Designers & Consultants
Pvt. Ltd., Mumbai
Manjalankal Construction
Sunanda Speciality Coatings Pvt. Ltd,
Mumbai Chemicals

Case Study of the Repair of a Major Bridge and Some Thoughts on Repair Materials
329

201

October 2004, Agra, India

REFERENCES
Smolcyk, H.G.,1976. Physical and chemical phenomena of carbonation.
Proceedings RILEM International symposium on carbonation of
concrete, Cement and Concrete Association, Wexham Springs, UK,
pp.10.
Bahadurpurkar, M.G., Godbole, U.B., 1999. Major structural repair to
GKG bridge at Andheri. National Conference on Corrosion Controlled
Structure, India Society of Structural Engineers, pp.345.
Guide For Repair Of Concrete Bridge Superstructures. ACI 546.1 lr-80,
1980. American Concrete Institute, Detroit, pp.20
Ingvarsson, H., And Ericksson, B., 1998. Hydrodemolition for bridge
repairs. Nordisk Betong (Stockolm), No 2-3. pp 49-54.
Caims John And Abdullahramli. July-August 1994. ACI Materials Journal,
Vol.91, no.4.
Sieely Carrol N. And Kelly Thomas Enp., 1991. Concrete surface
preparation coating and lining and inspection. National Association ofCorrosion Engineers, Houston.
Brett, M.A. And Brett, A.O., 1993. Electro-chemistry methods andapplication. Oxford University Press, pp.361.
Manjrekar, S.K., Manjrekar R.S. And Nair P.R.C., July 1996. Role ofpolymer – Cement-inhibitor comatrix in corrosion control of reinforcing
steel. The Indian Concrete Journal, Vol 70, No.7, pp 389-392.
CEB/FIP Model Code for Concrete Structures, 3rd Edition, 1978. Comite
Euro-international du Beton / Federation Internationale de laPrecontrainte, Paris, pp.348
Ohama Y., 1973. Study of properties and mix proportioning of polymer
modified mortars for buildings (in Japanese). Report on the Building
Research Institute, No.65, Tokyo, Japan.
Bullock, R.E., 1980. Factors influencing concrete repairs materials.
Concrete International: Design and construction, Vol 2 No.9, September,
pp.67-68.

202

New Technologies for Urban Safety of Mega Cities in Asia
330

DEVELOPMENT OF NEW METHODTO INSPECT DETERIORATED CONCRETE
USING NIR SPECTROSCOPIC TECHNIQUE
H. KANADA1, Y. ISHIKAWA2 AND T. UOMOTO3
Graduate School of Engineering, The University of Tokyo, Japan
2
Graduate School of Engineering, Shibaura Institute of Technology, Japan
3
Institute of Industrial Science, The University of Tokyo, Japan
kanada@iis.u-tokyo.ac.jp
1

ABSTRACT
Many non-destructive inspection methods have recently beendeveloped for concrete structures. However, these methods can obtain only
physical information of concrete, such as crack depth, delamination or
position of reinforcement etc. near its surface. Core boring or sampling may
be carried out for componential analysis in order to cover the lack ofchemical information. A remote non-destructive method that can detect
deterioration factors such as carbonation, chloride content or sulfate attack
would be an outstanding innovation in inspection methodologies. In thisresearch, remote non-destructive material detection of concrete is attemptedusing near-infrared [NIR] spectroscopy. The first step requires themeasurement of optical properties of components generated due todeterioration. A specific wavelength that can detect the target component
was determined from measured spectrums. Further, the capability ofquantitative analysis was confirmed using chemometrics. This enables us toobtain chemical information of concrete by just sensing reflected nearinfrared rays from the measuring plane. Since the existing methods are
restricted to measurements on small areas, a new near-infrared imaging
system was assembled using equipment already available. This system
consists of near-infrared irradiation equipment, imaging spectroscope andnear-infrared CCD camera. Dispersed near-infrared rays through thespectroscope can be received in each wavelength by light-sensitive element
on CCD camera. Finally, distribution or concentration of the target
component can be observed as an image. This paper describes the detection
method of carbonation, chloride and sulfate attack as examples.
Applicability of this method for inspection has been corroborated byexperimental results.
1.0 INTRODUCTION
Visual inspection is carried out as the first step of diagnosis ofdeteriorated concrete structures. Then, detailed inspections such as nondestructive testing methods or constitutive analysis may be done if
necessary. For example, delamination or loose portion of concrete can bedetected by using the infrared thermography method, and the ultrasonicmethod is used for measurement of crack depth. But deleterious substancesof concrete can not be detected by non-destructive inspection method. Core

203
331

October 2004, Agra, India

boring or sampling may be carried out for constitutive analysis in order toobtain chemical information. In the case of social infrastructures, theinspection area is large, and environmental condition or location may betough, therefore, it often requires high labor and cost in order to inspectconcrete structures. The applicability of diagnosis of deteriorated concrete
using near-infrared spectral imaging system is examined in this paper. Thismethod would prove to be a very effective technique for inspectors since it
can be remotely used to obtain chemical information on concrete surface.
2.0 APPLICATION EXAMPLE OF SPECTROSCOPIC TECHNIQUE
Near-infrared [NIR] spectroscopy had been developed in the area ofagriculture or food. Electromagnetic waves are absorbed or reflected fromany substance depending on the characteristics of their components.
Therefore, unknown components can be estimated if its optical properties
have been understood. Figure 1 shows the near-infrared image of tablets.
Left figure was captured in the visible range, right figure was captured bynear-infrared spectral imaging system.
Visible range

NIR chemical image

Figure 1 Near-infrared image of tablets (S. T. Japan Inc.)
Distribution of components can be observed from NIR image. Eachcomponent of tablet has its own characteristic optical properties, so
concentration of the component can be visualized as shading by capturing
spectral image at a specific wavelength. Figure 2 shows the opticalproperties of tablet components.
In this figure, the x axis shows the 2nd derivative spectrum, and y axis
the wavelength. 2nd derivative spectrum has local minimal value atabsorption peak of raw spectrum, and it has local maximum value atreflecting peak of raw spectrum (Figure 3).
As shown in Figure 2, Aspirin has an unique reflecting property at
1637nm, Acetaminophen and Caffeine also have unique absorption
properties at 2042, 2420nm respectively. Figure 4 shows component
distributions of tablets. Mixing ratio of components can be measured
remotely by image analysis, and these systems have already been installedat production lines of medicine manufacturing plants in order to check its
quality.

204

New Technologies for Urban Safety of Mega Cities in Asia
332

ICUS Report 6

AspirinRaw spectrum

A，dA，d2A

1st derivative spectrum

Acetaminophen
Caffeine

Figure 2: Optical properties oftablet components

2nd derivative spectrum

Raw spectrum
1st derivative spectrum
2nd derivative spectrum

Figure 3: Relationship between raw
spectrum and 1st, 2ndderivative spectrum

Figure 4: Component distributions of tablets (Spectral Dimensions Inc.)
3.0 APPLICATION OF NEAR-INFRARED SPECTROSCOPY TO
DETECT DELETERIOUS SUBSTANCES IN CONCRETE
Causes or grades of deterioration can be estimated from presence of
substances such as chloride, calcium carbonate, calcium sulfate, alkali silica
gel, rust etc. on concrete surface. In this research, steel corrosion due tocarbonation, chloride penetration and sulfuric acid attack were primarily
focused upon, and spectrum change due to deterioration was investigated.
3.1 Preparation of samples
Considering deterioration mechanisms, degeneration of cement
hydrates or penetration of detrimental constituent are main causes except incases of fracture due to external force or use of harmful aggregates.
Moreover, sand or course aggregate do not have unique optical properties innear-infrared range, so spectrum change of cement hydrates due todeterioration was focused. Cement paste samples were prepared in so as toobtain basic optical properties of concrete components. Samples,
40×40×160 mm in size, of chloride containing cement paste specimens(Table 1) were prepared. These proportions were determined according to
the chloride content on concrete surface described in “Standard
Specification for Design and Construction of Concrete Structures“(Japansociety of civil engineers). Chloride (sodium chloride) was directly added

Development of New Method to Inspect Deteriorated Deteriorated Concrete using NIR Spectroscopic Technique

333

205

October 2004, Agra, India

into the mixing water. Remixing was carried out to prevent segregation andto keep uniformity before casting.
Table 1: Mix proportions of samples
CementSample No.
N-50
N1-50
N2-50
N3-50
N4-50
N5-50
N6-50

Ordinary Portland cement W/C
Chloride content
Sample No.
(kg/m3)Not contained
N7-50
1.2
N8-50
1.5
N9-50
2.0
N10-503.0
N11-504.5
N12-506.0

50%Chloride content(kg/m3)
9.0
11.0
16.0
20.0
25.0
30.0

To verify spectrum change due to carbonation, specimen of N-50 was
placed in carbonation chamber until fracture plane pink coloration was notnoticed upon spraying phenolphthalein alcohol solution. To verify spectrum
change due to sulfuric acid attack, it was soaked in sulfuric acid.
3.2 Measurement of near-infrared spectrum
The near-infrared spectrums of samples were measured using a nearinfrared spectrometer (FOSS NIRSystems 6500 Series). The Spectralreflectance can be obtained from reflex ratio between sample and barium
sulfate used as standard white surface. The absorbance was adopted as theparameter of optical properties by converting reflectance (equation 1) in thiscaseAbsorbancelog 1 / Reflectance(1)

Figures 5 to 9 show the relationship between absorbance andwavelength of sample. The values shown have been averaged across fifty
measurements for the same sample. Measurement can be completed inseveral tens of seconds for one sample.
Normal cement paste
Carbonated cement paste

0.3

Normal cement paste

Calcium hydroxide
Calcium carbonate

Absorbance: A=log(1/R)

Absorbance:A=log(1/ R)

0.4
0.35

Carbonated cement paste

0.25
0.2
0.15
0.1

Absorbance decreases due
to carbonation at 1410nm

0.05

Calcium carbonate

Calcium hydroxide

0

-0.05
500

1000

1500
2000
Wavelength (nm)

2500

0.6

Normal cement paste
Deteriorated cement paste due to sulfuric acid attack
Calcium sulfate dihydrate

0.5
0.4
0.3

Deteriorated cement pasteDue to sulfuric acid attack

1750nm0.2
0.1
Normal cement paste

0

-0.1
500

Calcium sulfate dihydrate

1000

1500
2000
Wavelength (nm)2500

Figure 5: Spectrum change due Figure 6: Spectrum change due tosulfuric acid attack
tocarbonation

206

New Technologies for Urban Safety of Mega Cities in Asia
334

ICUS Report 6

Figure 5 shows spectrum change due to carbonation, spectrums of
Ca(OH)2 and CaCO3 are also shown for reference. Decrease of absorbanceat 1410nm can be observed due to carbonation. Ca(OH)2 in hydrated cementchanges to CaCO3, therefore, absorption properties of hydroxyl (-OH) were
found absent. Absorption peak at the wavelength is caused by 1st overtone
spectroscopy of the hydroxyl stretch vibration in calcium hydroxide.
Wavelength of 1410nm can be selected as characteristic waveband to verify
carbonation.
Deterioration due to sulfuric acid attack is often concerned for sewage
treatment equipments or structures in hot-spring area. Figure 6 shows
spectrum change due to sulfuric acid, and the spectrum for CaSO4•2H2O has
been shown for reference. Calcium sulfate dihydrate is produced due tochemical reactions between calcium hydroxide and sulfuric acid (eq. 2).

Absorbance: A=log(1/R)

Ca(OH)2+H2SO4→CaSO4•2H2O(2)Normal cement paste
Deteriorated cement paste due to sulfuric acid attack
Calcium sulfate dihydrate

0.3
-OH

H2O

0.2

CaSO4

0.1

0

1300

1400

1500
1600
Wavelength (nm)

1700

1800

Figure 7: Assignment of absorption peak of deteriorated samples
due to sulfuric acid attack
Some optical absorption peaks can be observed after deterioration(Figure 7), and absorption peak at 1410nm was found absent due toneutralization. Wavelength 1750 nm was selected as characteristic
waveband to verify deterioration caused by sulfuric acid since, compared toother peaks, it was independent and clear (F. M. Howari, et.al., 2002).
Figure 8 shows spectrum change from different chloride contents.
Increase of absorbance at 2266nm can be observed as chloride content
increases. The optical absorption peak can be seen clearer in Figure 9,
showing the enlarged figure at 2266nm after baseline offset. This behavior
is attributed to the fact that the vibration mode of cement hydrates ischanged by the action of chloride. Further details regarding thisphenomenon are currently being investigated. 2266 nm can be selected ascharacteristic waveband to quantify chloride content of cement paste.
Second derivative can remove the baseline offset and slope of theturbid interference, and emphasizes the peak of the spectrum (Figure 3).
This method is widely used for spectral analysis. Figure 10 shows the 2nd
derivative spectrums of samples. The effectiveness of second derivative
method can be seen by the accentuation of the absorption property at
2266nm when compared to Figure 9.

Development of New Method to Inspect Deteriorated Deteriorated Concrete using NIR Spectroscopic Technique

335

207

October 2004, Agra, India

Absorbance: A=log(1/R)( ) indicates chloride content of sample (kg/m3)

0.4
N12-50
N11-50
N8-50
N10-50
N6-50
N5-50

0.35
0.3

0.25
0.2

N9-50
N7-50
N4-50
N3-50

N2-50
N1-50
N-50

0.15
500

N-50(0.0)
N1-50(1.2)
N2-50(1.5)
N3-50(2.0)
N4-50(3.0)
N5-50(4.5)
N6-50(6.0)
N7-50(9.0)
N8-50(11.0)
N9-50(16.0)
N10-50(20.0)
N11-50(25.0)
N12-50(30.0)

1500
2000
2500
Wavelength (nm)Figure 8: Spectrum change from different chloride contents
Absorbance: A=log(1/R)

1000

0.28
0.26
0.24

N-50(0.0)
N1-50(1.2)
N2-50(1.5)
N3-50(2.0)
N4-50(3.0)
N5-50(4.5)
N6-50(6.0)
N7-50(9.0)
N8-50(11.0)
N9-50(16.0)
N10-50(20.0)
N11-50(25.0)
N12-50(30.0)

N12-50
N11-50
N10-50
N9-50
N8-50
N7-50
N6-50

0.22
( ) indicates chloride content of sample (kg/m3)

0.2
2100

2150

2200 2250 2300
Wavelength (nm)

2350

2400

Figure 9: Enlarged figure at 226 6nm after baseline offset
3.3 Introduction of regression analysis
Regression analysis should be carried out when the relationshipbetween component and optical properties is required. The simplest methodof calibration is based on a single independent variable (wavelength), andused for estimation of chloride content. The assumption is that constituent
value c (concentrations) are linear function of the 2nd derivative spectrum
A˝ at some wavelength i:c

K 0

K 1 Ai(3)

The least squares approach fits the line so as to minimize the sum ofsquares of deviations between data points and the calibration line and yields
two calibration constants: intercept K(0) and slope K(1). Those deviations
are taken along the concentration axis, and are hence called concentration
residuals. Chloride content of concrete can be easily estimated from the208

New Technologies for Urban Safety of Mega Cities in Asia
336

ICUS Report 6

calibration curve. In this case, this curve was determined from second
derivative spectrums and concentrations:c0.79 2461 A 2266

(kg/m3)(4)

The chloride content of sample can be estimated by substituting thevalue of second derivative spectrum at 2266 in equation 4. Figure 11 shows
the relationship between calculated value from calibration curve and actual
value, a very high correlation (R2=0.99) was obtained. Therefore, accurate
calibration curve can be obtained in above steps, and chloride content can be
estimated from optical spectrum.

Calculated value (kg/m 3)30
25

R2=0.99

20
15
10
5
0

0

5
10
15
20
25
Actual measurement value (kg/m 3)

30

Figure 11: Relationship between calculated value and actual
measurement
4.0 DETECTION OF DELETERIOUS SUBSTANCES OF
CONCRETE USING NEAR-INFRARED SPECTRAL IMAGINGSYSTEM
Since the near-infrared spectrometer can be used to measure thespectrum only at a fixed point, the spectral imaging system is required fortwo-dimensional scans.
4.1 Introduction of near-infrared spectral imaging system
Near-infrared spectral imaging system was introduced in order todetect distribution or concentration of deterioration factors remotely. Thissystem consists of near-infrared irradiation equipment, imaging
spectroscope and near-infrared CCD camera. This system consists of nearinfrared irradiation equipment, imaging spectroscope and near-infrared
CCD camera. Dispersed near-infrared rays through the spectroscope can bereceived in each wavelength by light-sensitive element on CCD camera(Figure 12).

Development of New Method to Inspect Deteriorated Deteriorated Concrete using NIR Spectroscopic Technique

337

209

October 2004, Agra, India

C o m p uterN ea r-in fra red
C C D ca m era

x AxisC C D C a m era
Im S p ecto r
L ig ht S o u rce

O b jectiv e L en s

W a v elen g th A x is

C o ntro l co m pu ter
Sp ec troscop e

Light Intensity

L ig h t sou rce

L ig ht-sen sitiv e E le m en t o n C C D C a m e rax A x isW a v elen g th A x is
1000

S ta nd ar d w hite b oa rd

1500

2000 nmO p tica l P ro perties o f Ｘ P o int

M easu rin g p lan e

T a rg et

E ntra nce
O b jectiv e Slit
L en sN IR C C D C a m era

Im S pe cto r

PG P

Figure 12: Near-infrared spectral imaging system
4.2 Detection of carbonated area by NIR spectral imaging system
Detection of carbonation area was attempted by the system referring
the result from obtained optical properties by spectrometer. Reflected nearinfrared light from measuring plane through the spectroscope is received,
and then spectral image at arbitrary wavelength can be shown (Picture 1).
CO2

CO2

CO2
CO2

CO 2

CO2

CO2

CO2

FigureFigure 13: Spectral image andvisible image ofconcrete specimen

CO2

CO2

14:

Spectral image andresult of EPMA analysis(Carbonation)

Figure 13 shows spectral image at 1410nm and optical image of aconcrete specimen. The image in the left was obtained using the nearinfrared spectral imaging system. Red pixels indicate non-carbonated area
because calcium hydroxide absorbs near-infrared light of 1410nm, so thearea is captured as dark. The image in the right was captured using a normal
digital camera. Measuring plane was colored by spraying phenolphthalein
alcohol solution. Figure 14 also shows spectral image at 1410nm and resultof EPMA analysis (Target:C) of cement paste specimen. Good agreements
between carbonated area detected by spectral image and traditional methods
were observed.
Near-infrared CCD camera

Lig
ht

so
urc
e

Spectroscope

Specimen

Picture 1: Actual scanning inlaboratory
210

New Technologies for Urban Safety of Mega Cities in Asia
338

ICUS Report 6

4.3 Detection of chloride penetration by NIR spectral imaging system
Detection of chloride penetration was also attempted using thesystem. Figure 15 shows spectral image of 2266nm and result of EPMA
analysis (Target:Cl). Cement paste specimen was soaked in salt water, so
chloride was penetrated form its surface. Chloride containing cement paste
absorbs near-infrared light of 2266nm, so high chloride concentration area
appears dark.
Salt water

Salt water

Salt water

Salt water

Salt water
Crack

Salt water

Salt water

Figure 15: Spectral image and result of EPMA analysis (Chloride)
Distribution of chloride concentration can be obtained by image
analysis (Figure 16). It was confirmed that chloride penetration can be also
detected by the system from the experimental results.
Chloride content (kg/m3)

27+
24 to 27
21 to 24
18 to 21
15 to 18
12 to 15
9 to 126 to 93 to 60 to 3

20
10
0

Crack

0

20
10

Figure 16: Distribution of chloride concentration
5.0 APPLICATIONS FOR FIELD INSPECTION
At the present stage, laboratory experiments have been carried out
because performance of NIR spectral imaging system is not high. Someapplications for field inspection will be expected. In case of concrete
structures near seashore, chloride content on concrete surface or cover may
be measured in order to estimate or investigate corrosion level of steel bars.
If distribution of chloride concentration on concrete surface can be detected
remotely, chloride penetration will be estimated approximately using Fick’s
diffusion equation. Moreover, number of core sampling would be proved toreduce since high chloride concentration area can be scanned twodimensionally. As shown in Figure 17, unnecessary sampling can be

Development of New Method to Inspect Deteriorated Deteriorated Concrete using NIR Spectroscopic Technique

339

211

October 2004, Agra, India

reduced and inspectors can designate the positions of boring from NIR
spectral image. Fiber sensors can be also used for inspection of interior of
concrete when information of internal deterioration is required. Carbonation
depth, deterioration depth due to acid attack or chloride content at arbitrary
depth can be measured using NIR fiber optic sensor (Figure 18).
Surface of concrete structure Distribution of chloride concentration(Visual inspection)(NIR spectral image)

Chloride concentration

Designation of core sampling

Chloride concentration

Random core sampling

Figure 17 Core sampling using
NIR
spectral
image

10mm

NIR fiber optic sensor

Drilling hole

Figure 18 Inspection of interiorof concrete using NIR fiber
optic sensor

6.0 CONCLUSIONSIt has been shown that deterioration factors of concrete such ascarbonation, sulfuric acid attack or chloride penetration can be detectedfrom their optical properties, and methods for obtaining quantitative valuesof chloride content, etc. have been illustrated in this work. This method
would be applicable to other deleterious substances too, if they havecharacteristic optical properties in near-infrared range. The Near-infrared
spectral imaging system was also introduced to obtain the two-dimensional
spectrum of the measuring plane. The applicability of the method has been
corroborated by comparison of the results with those obtained using
traditional methods.
REFERENCES
S. T. Japan Inc. Product catalogue of near-infrared spectral imaging system.
(In Japanese).
Spectral Dimensions Inc.: Product catalogue of MatrixNIR.
Japan society of civil engineers. Standard Specification for Design andConstruction of Concrete Structures, 2002. (In Japanese).
F. M. Howari, P. C. Goodell, S. Miyamoto. 2002. Spectral Properties ofSalt Crusts Formed on Saline Soils. Journal of Environmental Quality,
31:1453-1461.

212

New Technologies for Urban Safety of Mega Cities in Asia
340

VULNERABILITY ASSESSMENT OF
EXISTING ENGINEERED AND NON
ENGINEERED STRUCTURES OF DHAKACITY USING RVS AND NDT TECHNIQUESMEHEDI A. ANSARY AND MUNAZ A. NOOR
Department of Civil Engineering, BUET, Dhaka, Bangladesh
ansary@ce.buet.ac.bd
ABSTRACT
Bangladesh is an earthquake-prone country. Although, a large part of
the urban building stock is engineered but the quality of the construction isunsatisfactory. Luckily, the recent major earthquakes have occurred awayfrom the city. The history of the region indicates that there is a strong
possibility of major earthquakes occurrence that could cause extreme
devastation. In fact recent studies demonstrated that even moderate
earthquakes could be fatal in populated, unplanned cities. General public
and the engineering community are becoming more and more aware of thesituation. However, neither the possible extents of seismic damage ofexisting buildings are known nor there is any guideline for theirstrengthening measures. Even the performance of the engineered buildings
under a seismic event is questionable, as enough work has not yet been donein this field.
The methodology for conducting a successful insitu investigation
includes: strategic planning, preliminary visual inspection, loadingassessment, material property evaluation and load testing techniques. The
single most sought after material property used for the evaluation ofresidual load capacity and structural adequacy of deteriorated concrete
structures is the insitu concrete strength. This study has presented theresults of seismic vulnerability assessment of some existing engineered andnonengineered buildings of Dhaka City using Rapid Visual Screening
Technique and has also estimated insitu concrete strength of some existingbuildings by carrying out non-destructive tests. Finally using the collected
insitu information seismic performance of one-engineered building has beenassessed by structural modeling.
1.0 INTRODUCTION
The 1997 Chittagong Earthquake (Sabri, 2002), the 1999 Moheskhali
Earthquake (Ansary et al., 2001) and the 2003 Rangamati Earthquake(Ansary et al., 2003) revealed the vulnerability of “non-earthquake-proof”
cities and villages in southeastern part of Bangladesh. In 1897, anearthquake of magnitude 8.0 caused serious damages to buildings in thenortheastern part of India (including Bangladesh) and 1542 people were
killed. Recently, Bilham et al. (2001) pointed out that there is highpossibility that a huge earthquake will occur around the Himalayan region

213
341

October 2004, Agra, India

based on the difference between energy accumulation in this region andhistorical earthquake occurrence. The population increase around this region
is at least 50 times than the population of 1897 and cities like Dhaka,
Chittagong, Kathmandu, Guwahati have population exceeding several
millions. It is a cause for great concern that the next great earthquake may
occur in this region at any time. According to a report published by United
Nations IDNDR-RADIUS Initiative, Dhaka and Tehran are the cities withthe highest relative earthquake disaster risk (Cardona et al., 1999). Once agreat earthquake occurs, Dhaka will suffer immense losses of life andproperty and will not be able to function as the capital of Bangladesh.
After the recent 2003 Rangamati Earthquake people of Dhaka City
which is one of the densest areas in the world has become frightened
regarding the quality of their houses. Especially the students of residential
halls of Dhaka University (DU) have requested their authority to assess theirhalls and strengthen them. Under this circumstance, the authors have beenrequested by the DU authority to provide expert advice on this issue. Figure
1 shows the location of Dhaka and DU with respect to Bangladesh.
Accordingly, a Rapid Visual Screening (RVS) (FEMA-154, 2002)
survey has been carried out for all the buildings of DU. A detailed
evaluation for some of the buildings with low RVS score have also been
undertaken. Initially two buildings one nonengineered and the otherengineered have been selected for detailed evaluation. For this purpose nondestructive testing have been planned and carried out for the selectedbuildings. The obtained material data and other information have been usedin the analysis of the structural model of the engineered structure.
This paper presents the findings of the non-destructive tests
undertaken for the two buildings and the findings of the structural analysisof the engineered building. It also includes discussion of the results andprovides recommendations for future study.
2.0 EXISTING STRUCTURES OF DHAKA UNIVERSITY
Dhaka University (DU) is the premier university in Bangladesh, it wasestablished in 1921. According to a recent survey (DU Chief Engineer,2004) of the DU buildings, it has been found that there exist 165 official
buildings within the campus. The buildings can be mainly classified into
three categories: British Period (1757-1947), Pakistan Period (1947-1972)
and Bangladesh Period (1972 to date).
Table 1 shows that among 165 buildings of DU, 61% are of Brick
Masonry and the rest 39% are of reinforced concrete (RCC). This pattern ofbuilding construction has also been observed from the existing building
typologies of Dhaka City (Ansary, 2004). Before undertaking a detailed
survey, Rapid Visual Screening method (FEMA-154, 2002) has been
undertaken for each of those 165 buildings. RVS for moderate seismic zone
has been used as Dhaka falls in Zone-2 of Seismic Zoning Map ofBangladesh (BNBC, 1993) as shown in Figure 2.

214

New Technologies for Urban Safety of Mega Cities in Asia
342

ICUS Report 6Surja Sen
Hall

BritishCouncilFigure 1: Location map of Dhaka City and Dhaka UniversityVulnerability assessment of existing structures of Dhaka City using RVS and NDT Techniques
343

215

October 2004, Agra, India
Almost all of the buildings have got a final score less than two. The
primary reasons for this is that the buildings have either horizontal orvertical irregularities or both. The soil in DU area is stiff soil, which also
reduces the score. Figure 3 shows two typical buildings of British and
Bangladesh periods.
Table 1: Types of existing buildings within DU

1905-1942
1952-1970
1972-2003

23
42

Construction
Period3
5
5

Maximum
StoreyConstruction
Period7
61
32

RCC Structure
NumberMaximum
StoreyBritishPakistan
Bangladesh

Brick Masonry Structure
NumberPeriod610

1958-1970
1972-2003

Figure 2: Seismic zoning map of Bangladesh (BNBC, 1993)
3.0 NON-DESTRUCTIVE TESTING
Among the DU buildings, two buildings have been selected forcarrying out necessary non-destructive tests to obtain required in-situ
concrete strength and other parameters for developing structural model andanalysis. One is brick masonry and the other is reinforced concrete building.
Figure 1 also shows the locations of these buildings.

216

New Technologies for Urban Safety of Mega Cities in Asia
344

ICUS Report 6Curzon Hall, 1905

Amar Ekusey Hall, 2002

Figure 3: Typical buildings of British and Bangladesh periods
3.1 British council complex
This complex is located at Fuller road, Dhaka University. The
complex has four brick masonry buildings all constructed in late 1950s.
Schimdth Hammer and Micro Covermeter tests at selected locations of threeof the buildings have been carried out. Also concrete core tests on collected
samples and tensile strength tests on collected mild steel bar have been
performed. Figure 4 shows the above mentioned tests been carried out on
British Council buildings.
After conducting Schimdth Hammer test, following concrete strength
have been obtained for roof slab: 267 MPa (9 locations); for beam: 316MPa (3 locations). Using the Micro Covermeter equipment, main bar
diameter and spacing and concrete clear cover have been determined forroof slabs and beams. Also three 48 mm diameter concrete cores have beencollected from roof slab. Average concrete strength from the cores is 282MPa. Three 6 mm diameter plain bars have been collected and tested in thelaboratory with average yield strength of 28033 MPa.
3.2 Surjo sen hall complex
This student hall complex is located close to the Administrative officeof DU. About 1200 students reside here. There are altogether twelve
different buildings in the complex: five 5-story, two 6-story, one 3-story,
three single-story and one auditorium. Accept one 5-story house tutors
bungalow, other 5 and 6-story buildings are connected with 1-inch
expansion joint in between. All these buildings are ordinary moment
resisting frame structures of reinforced concrete and were constructed in
1965. Figure 5 shows the plan of a 6-story building with two expansion
joints at two ends. This building has a lift core and stair at one end.
Schimdth Hammer test have been carried out on the lift core, beams,
columns and slabs of ground floor, third floor and the top floor of a 6-story
building. Following concrete strength have been obtained for roof slab:
195 MPa (6 locations); for beam: 165 MPa (6 locations); for column: 16
 5 MPa (6 locations); for lift core 124 MPa (6 locations).

Vulnerability assessment of existing structures of Dhaka City using RVS and NDT Techniques
345

217

October 2004, Agra, India

Figure 4: Non-destructive tests being carried out


6-

6-

6-storied

5-

5-

66-

Figure 5: Plan, elevation and expansion joints of a 6-storey
building, Surjo Sen Hall




218

New Technologies for Urban Safety of Mega Cities in Asia
346

ICUS Report 6


4.0 STRUCTURAL MODEL AND ANALYSIS
Figure 5 shows plan and elevation of a 6-story building of Surjo Sen
Hall, which has been used for this investigation. The building has utilized astructural system with moment resisting frames having a lift core. All
columns are 255x610 mm size and beams are of variable sizes: 150x610
mm, 150x1020 mm, 255x455 mm and 255x610 mm.
The analyses of the buildings have been carried out separately in thelongitudinal and transverse directions using a finite element software
ANSYS (1999). The first five modes and mode shapes of the elastic
building without and with slabs are presented in Table 2. Figure 6 shows thefirst mode of the building without slab and Figure 7 shows the first mode of
the building with slab.
Modes

Table 2: Periods for different modal vibrations.
Without
Mode Shape
With Slab Mode Shape
Slab
Period (s)Period (s)

1

6.52

2

5.72

Cantilever along 5.99
long direction
Torsional
4.71

3

4.78

Torsional

3.77

4
5

3.83
2.77

Torsional
Double crossing

1.93
1.46

Torsional
Cantilever along
long direction
Cantilever along
short direction
Double crossing
Breathing

The building has been analyzed for equivalent static load method(EQSM) and response spectrum method (RSM) following BNBC (1993)
guideline. According to BNBC (1993), the design earthquake response
spectrum for different types of soils is as shown in Figure 8. For the present
study design response spectrum for soil type S2 i.e., stiff clay has been used.
The building has been analyzed without considering any vertical loads. The
analysis results are presented in the next article.
B

B

5.0 RESULTS AND DISCUSSIONS
From the finite element analysis of the engineered structures of Surja
Sen hall maximum top floor displacement have been estimated using theequivalent static load method (EQSM) and response spectrum method(RSM). The results are provided in Table 3. Figure 9 presents the structural
analysis solution of the building without slab using RSM.
Table 3: Maximum top floor deflection (mm).
Method ofAnalysis
EQSM
RSM

Without Slab Period (s)Long Direction
Short Direction
47
16
111
73

With Slab Period (s)Long Direction
Short Direction
9
10
56
106

Vulnerability assessment of existing structures of Dhaka City using RVS and NDT Techniques
347

219

October 2004, Agra, India

Non-destructive test (NDT) has provided very low insitu concrete
strength and modulus as discussed earlier. Due to this the building has very
long time period, which makes the building very flexible. From earthquake
point of views, the building may absorb high energy but the deflection limit
may be exceeded (as observed from Table 3), which demands high member
ductility. But from the structural drawing, it has been found that the ductility
detailing is absent in this building. During an earthquake this building may
not be able to generate the desired deflection and eventually may collapse.
To obtain the actual behavior of the building pushover analysis will be
required. Also this building will need some strengthening to satisfy theearthquake demand.

Figure 6: First mode of the building without slabFigure 7: First mode of the building with slab

220

New Technologies for Urban Safety of Mega Cities in Asia
348

ICUS Report 6



Figure 8: Normalized response spectra for 5% damping (BNBC, 1993)









Figure 9: Deflected shape of the building without slab using RSM

Vulnerability assessment of existing structures of Dhaka City using RVS and NDT Techniques
349

221

October 2004, Agra, IndiaACKNOWLEDGEMENTS
The authors would like to acknowledge the financial support provided
by CASR, BUET. Also they would like to thank DU authority to allow themto carry out RVS survey and NDT test.
REFERENCES
Ansary, M.A., T.M. Al-Hussaini, M. Sharfuddin and J.R. Choudhury, 2001.
1999. Moheskhali earthquake: a damage study. Journal of Asiatic
Society of Bangladesh, 27 (2), 139-149.
Ansary, M.A., A. Sadek and T.M. Al-Hussaini, 2003. 2003. Rangamati
earthquake – an engineering assessment. Proc. of the Seminar on 2003
Rangamati Earthquake, Organized by Disaster Management Bureau,
Ministry of Disaster Management and Relief, Government of
Bangladesh and Bangladesh Earthquake Society, Dhaka, September 4,
2003.
Ansary M.A., 2004. Seismic loss estimation of Dhaka for an earthquake ofintensity VII. Oriental Geographer, 48(1), 1-16.
ANSYS 5.6, 1999. ANSYS Inc., USA.
Bilham, R., V.K. Gaur and P. Molnar, 2001. Himalayan seismic hazard.
SCIENCE, 293.
BNBC, 1993. Bangladesh National Building Code. HBRI-BSTI.
Cardona, C., R. Davidson and C. Villacis, 1999. Understanding urban
seismic risk around the world. Summary Report on the Comparative
Study of the United nations International Decade for Natural Disaster
Reduction, RADIUS Initiative.
DU Chief Engineer, 2004. Building data collection of Dhaka University
campus. Personal Communication.
FEMA-154 (ATC-21), 2002. Rapid Visual Screening of Buildings for
Potential Seismic Hazards: A Handbook.
Sabri, S.A., 2002. Earthquake intensity-attenuation relationship for
Bangladesh and its surrounding region M. Engg. Thesis, BUET, Dhaka.




222

New Technologies for Urban Safety of Mega Cities in Asia
350



MAINTENANCE MANAGEMENT OF
CONCRETE STRUCTURESBY USING REPAIR-RISK
YOSHITAKA KATO
Institute of Industrial Science, University of Tokyo, Japankatoyosh@iis.u-tokyo.ac.jp


ABSTRACT
Prediction of deterioration of concrete structures was often executedusing uncertain information, because the quality of concrete structuresdiffered from the design due to construction errors. Therefore, it was very
difficult to judge what repair/reinforcement should be selected, or when the
repair/reinforcement should be done. To deal with that problem, it wasconsidered to be very useful to acquire the information to predict thedeterioration of concrete structures by inspection. Though physicalinspection of actual structures can lead to more accurate results andpredictions, such inspections are time consuming and are not as beneficial
for application to large structures requiring maintenance. In this research,evaluation of the value of inspection technique in maintenance management
was quantitatively done using repair risk, a factor proposed in this research.
1.0 INTRODUCTION
The Ministry of Land, Infrastructure and Transport (2003) forecasted
that infrastructure maintenance cost in Japan would be about 9 trillion yen
in 2025 which would be about 70 to 80 % of the entire construction
investment. Especially, huge stocks which were constructed at the higheconomic growth period will be about 50 years old in 2020. As a result, themaintenance cost will drastically increase from that time. To deal with thatproblem, some researchers tried to apply “Asset Management” to maintainthe stocks efficiently. But, it doesn't go well easily.
In order to do “Asset Management” appropriately, it is a minimum
requirement to predict the future performance of structures. But, theprediction of deterioration of a concrete structure should be often executed
under uncertain information, because the quality of concrete structures may
differ from the design due to construction errors. Therefore the accuracy of
prediction results may be low. This leads to difficulty in the selection of therepair/reinforcement methods and its timing. To deal with this problem, it isvery useful to acquire the information by using several kinds of inspection
techniques, such as ultra-sonic test, infrared thermograph, etc. Thoughphysical inspection of actual structures can lead to more accurate results andpredictions, such inspections are time consuming and are not as beneficial
for application to large structures requiring maintenance.

223
351

October 2004, Agra, India


25

15
10
5

20
cumulative

400

16

distribution

4

0

0
20
00

100

19
90

8

19
80

200

19
70

12

19
60

300



distributed stock (trillion yen)

500

20
25

20
10

19
95

19
80

19
65

0

19
50

cumulative stock (trillion yen)disaster
new const.
maintenance

20

19
50

const. investment (trillion yen)

Figure 1: Construction investment and transition of amount of stock
In this research, evaluation of the value of inspection technique inmaintenance management was quantitatively done using “Repair-Risk”, afactor proposed in this research.
2.0 WHAT IS UNCERTAIN INFORMATION?
In this research, corrosion-induced damage due to salt attack was
selected as the case study of evaluating the value of inspection techniqueunder uncertain information, because this phenomenon causes the serious
deterioration of concrete structures and also can be predicted by moderate
accuracy. When the prediction of this phenomenon is performed, therequired information that depends on the applied model is as follows. 1)
apparent diffusion coefficient of Cl- in cover concrete, 2) thickness of coverconcrete, 3) Cl- content at surface concrete(environmental condition). Then,
Cl- content at surface concrete is governed by environmental condition suchas distance from seashore, wind, temperature, humidity, and so on. Clcontent at surface concrete is also uncertain information, but there is little
research available for its calculation. Therefore, the influence of Cl- content
at surface concrete was neglected in this research. In addition, the accuracyof prediction result is also governed by the applied model. The model is also
considered to be a kind of uncertain information. But in this research, thesame model was applied to predict that phenomenon, the influence of224

New Technologies for Urban Safety of Mega Cities in Asia
352

ICUS Report 6applied model was considered to be negligible. As a result, the apparent
diffusion coefficient of Cl- of cover concrete and the thickness of coverconcrete were considered as the uncertain information in this research.
3.0 MODEL OF CORROSION-INDUCED DAMAGE DUE TO SALTATTACKThe deterioration process of corrosion-induced damage due to salt
attack is shown in Fig. 2. The corrosion of steel reinforcement begins at theend of stage1. According to JSCE (2002), this time is defined such that thedensity of Cl- at surface of steel reinforcement reaches 1.2 (kg/m3). Next,
the corrosion crack is generated at the end of stage2. This time is also
defined such that the amount of corrosion reaches 10 (mg/cm2). In order tosimulate stage1 situation, the diffusion analysis based on Fick’s second law
was conducted and for stage2, the proposed model by Matsumura et al(1999) was used.
Stage1

Stage2
Steel

Stage3
Steel

ClCl-

Stage4
Steel

ClCl-

H2O

O2

ClCl-

H2O

O2

Figure 2: Deterioration process of corrosion-induced damage due to salt
attackThe period of stage1 was calculated by equation (1). This equation istheoretical solution of Fick’s second law of diffusion under the constantboundary condition.
C( x , t )  C 0 (1  erf

x
2 D0t

)

(1)

where, C: Cl- content (kg/m3), C0: Cl- content at surface of concrete (kg/m3),
x: distance form concrete surface (cm), D0: apparent diffusion coefficient ofCl- (cm2/year), t: time (year), erf: error function
The period of stage2 was calculated by equation (2). This model was
based on the relation between corrosion speed of steel reinforcement andconcrete resistance.

Maintenance Management of Concrete Structures using Repair Risk
353

225

October 2004, Agra, India

where, Vcorr: corrosion speed (mg/cm2/year), RRc: reciprocal of concrete
resistance (1/), A: constant (-1.216), L: thickness of cover concrete (cm),
H: relative humidity (%).
4.0 SETUP OF UNCERTAIN INFORMATION
The apparent diffusion coefficient of Cl- and the thickness of coverconcrete were considered as uncertain information. Setups for of each set of
information are described in the following sections.
4.1 Setup of apparent diffusion coefficient of ClThere were a lot of measurement results of apparent diffusion
coefficient of Cl-. However, these results could not be simply comparedbecause the method of calculating the apparent diffusion coefficient of Clwas different among researchers. To deal with that problem, Maeda et al(2002) re-analyzed 1500 data sets that were reported by the investigations in
27 years. Figure 3 is one example of analysis results. The relation between
water cement ratio (W/C) and apparent diffusion coefficient of Cl- (DCl) is
shown in this figure. And the dispersion of DCl is also shown in this figure.
This result was used in this research.

DCl (cm2/sec)

10-5
10-6
10-7
10-8
10-9

30

40

50
W/C (%)

60

70

Figure 4: Relation between W/C and DCl [4]226

New Technologies for Urban Safety of Mega Cities in Asia
354

ICUS Report 6


40

Ave

Max

Min

average (mm)

30
20
10
0
-10
-20
-30
side side side side side side side side
A
B
C
D
E
F
G
H

standard deviation (mm)Figure 5: Average of construction error
16

Ave

Max

Min

12
8
4
0
side side side side side side side side
A
B
C
D
E
F
G
H

Figure 6: Standard deviation of construction error
4.2 Setup of thickness of cover concrete
It is very difficult to quantitatively evaluate the dispersion of thicknessof cover concrete due to construction error. Setup of that dispersion was
conducted based on the investigation results (Tanimura et al. 2003). Figure
5 shows the average of construction error. The plus value of vertical axis
means that the thickness of cover concrete is thicker than that of design, andthe minus value means the opposite situation. Figure 6 shows the standard
deviation of construction error. These results were utilized in this research.
5.0 EVALUATION OF VALUE OF INSPECTION TECHNIQUE
5.1 Prediction of corrosion-induced damage due to salt attack
Figure 7 shows the examples of prediction results (Tcc means
thickness of cover concrete). Analytical conditions are W/C = 0.5, Tcc = 10(cm) and C0 = 13 (kg/m3) and the dispersion of DCl and Tcc were set basedon Section 4. From this figure, it could be found that the corrosion crack
occurs from 8 to 114 years. The probability density distribution of corrosion
crack generation time are shown in Figure 8. Then, Tcc being kept at 10 (cm),W/C and C0 were changed in this simulation.

Maintenance Management of Concrete Structures using Repair Risk
355

227

October 2004, Agra, Indiaamount of corosion (mg/cm2)

20
Tcc-Max ，DCl-Min
Tcc ＆DCl-Ave
Tcc-Min，DCl-Max

15
8years10114years

50
050
time (year)

100

Figure 7: Calculation result of amount of corrosion

probability density

0.03

W/C=0.5,C0=13
W/C=0.5,C0=9
W/C=0.6,C0=9

0.02

0.01

0
0

20

40

60

80

100

time (year)

Figure 8: Probability density distribution of corrosion crack generationtime
5.2 Calculation of “Repair-Risk”
In this research, the dispersion of prediction result was measured with
“Repair-Risk (RR)” and it was calculated with probability density
distribution of corrosion crack generation time (Pc), repair cost (Rc) andrepair frequency (Rf). The calculation conditions are as follows:






Repair method: Desalination (cost = 1, validity time = 20 (years))Service period: 100 years
Periodic inspections are conducted in every 5 years(RR)i = (Pc) × (Rc × Rf)i x (Rc × Rf)d at time =i(RR)i was calculated at each periodic inspection (see Figure 9).
Then, (Rc × Rf)d means total repair cost at design (design means
there are no dispersions of DCl and Tcc).



RR   (RR ) i : p means the time when the value is evaluated (see

100
i p

Figure 10)

228

New Technologies for Urban Safety of Mega Cities in Asia
356

ICUS Report 6
W/C=0.5,C0=13
W/C=0.5,C0=9
W/C=0.6,C0=9

0.15

(RR)i

0.1

0.05

0
0

20

40
60
time (year)

80

100

Figure 9: Calculation result of (RR)i1

W/C=0.5,C0=13
W/C=0.5,C0=9
W/C=0.6,C0=9

0.8

RR

0.6
0.4
0.2
0
0

20

40

60

80

100

time (year)

Figure 10: Calculation result of RR
5.3 Evaluation of value of inspection techniqueFigure 11 shows RR in case of measuring DCl or Tcc (W/C = 0.5, C0 =13 (kg/m3)). In case of measuring DCl, DCl was constant, but dispersion of
Tcc remained. In case of Tcc, the opposite situation can be seen. From thisfigure, it could be found that measuring DCl can decrease RR more than
measuring Tcc in this case study. Figure 12 shows the result of subtracting
Figure 11 (measuring DCl) from Figure 10. Vertical axis shows the amountof decreasing RR, meaning the value of inspection. Naturally, larger values
denote higher values of inspection. From this figure, the order of the heightof value of inspection depends on the time. Therefore, it was concluded thatthe structure that should be inspected by priority that can be judged by using
this evaluation method.
6.0 CONCLUSION
In this research, the evaluation method of value of inspection
technique under uncertain information was proposed. The proposed model
can judge structures requiring inspection by proprietors. However, costeffectiveness of inspection was not examined, and also the number of case

Maintenance Management of Concrete Structures using Repair Risk
357

229

October 2004, Agra, India
study was limited. The proposed model should be modified to deal withsuch a problem.
0.4
measure DClmeasure Tcc

RR

0.3

W/C=0.5, C0=13

0.2
0.1
0
0

20

40

60

80

100

time (year)

Figure 11: RR in case of measuring DCl/Tcc
W/C=0.5C0=13
W/C=0.5C0=9
W/C=0.6C0=9

value of inspection

0.8
0.6

measure DCl

0.4
0.2
0
0

20

40

60

80

time (year)100

Figure 12: Calculation result of value of inspection
REFERENCES
JSCE, 2002. Concrete standard specifications (construction) (in Japanese)
Maeda, S., Takewaka, K., Yamaguchi, T. and Yoshimoto, K., 2002.
Analysis of Data on Chloride Diffusion Process into Concrete,
proceedings of the JCI, Vol.24 (in Japanese)
Matsumura, T., Kanazu, T. and Nishiuchi, T., 1999. An Evaluation Method
for Corroding of Reinforcement in Concrete Structure Located in
Seashore Atmosphere, Journal of Materials, Concrete Structures andPavements, JSCE, Vol.634, pp.303-314(in Japanese)
Tanimura, Y., Hasegwa, M., Sogabe, M. and Sato, T., 2003. Construction
Error of Concrete Cover in Railway Viaduct, proceedings of the JCI,
Vol.25, No.2, pp.1843-1848(in Japanese)
The Ministry of Land, Infrastructure and Transport, 2003. White paper on
Land, Infrastructure and transportation in Japan (in Japanese).

230

New Technologies for Urban Safety of Mega Cities in Asia
358

INFLUENCE OF FIBRE WRAPRETROFITTING ON GRAVITY DESIGNEDRC BEAM-COLUMN JOINTS UNDERCYCLIC LOADINGK K BAJPAI, C V R MURTY AND DURGESH C RAI
Department of Civil Engineering, Indian Institute of Technology Kanpur
kunwar@iitk.ac.in
ABSTRACT
Some RC frame buildings in India suffered severe damage in recent
earthquakes due to poor detailing of joint reinforcement. Indian standards
do not have detailed design guidelines for determining the amount oftransverse shear reinforcement in joints and anchorage of longitudinalbeam bars in columns. It is therefore important to evaluate the performanceof beam-column joints of existing buildings and to devise suitable
retrofitting techniques for improved seismic behavior of these lateral load
resisting moment frames.
This paper presents details of one of a series of twelve beam-column
specimens with different joint details tested up to failure under reverse
cyclic loading and retrofitted in the joint failure region using glass fabricreinforced plastic (GFRP) composite. The effectiveness of retrofitting using
GFRP composite for RC beam-column specimens was studied for improving
the seismic performance of RC joints. The specimen retrofitted with GFRP
composite showed improved strength and marginally improved energy
dissipation characteristics under reverse cyclic testing when compared withoriginal specimen. However, there is no improvement in the ductility of thejoint.
1.0 INTRODUCTION
Much of the civil infrastructure is in need of repair or replacement as aresult of damage caused by heavy use and exposure to the environment.
There is additional demand on repair and retrofitting caused by natural
disasters like earthquakes. The fiber reinforced polymers (FRP) are
relatively new materials but they have already become important
engineering materials. The properties of FRP’s like high strength-to-weightand stiffness-to-weight ratios, corrosion resistance, light weight andpotentially high durability make them very attractive for use in civil
infrastructure. Recently, the new retrofit method for reinforced concrete(RC) structures using FRP’s is getting attention due to its advantages overconventional retrofitting techniques like steel jacketing and shortcreting etc.
Their use has significantly increased in the retrofitting of RC structures dueto their tailor able performance characteristics.

27359

October 2004, Agra, India

Good seismic performance of RC frames is achieved in frames thathave the ability to (a) avoid a sudden development of collapse mechanism
during strong earthquake shaking, and (b) absorb seismic energy throughinelastic deformations. These objectives are met at global and local levels
while designing a RC frame system. At the global level, a suitable collapse
mechanism is chosen which distributes the inelasticity uniformly
throughout the structure but at specific regions, which enhances overall
energy dissipation potential and limits the inelastic demand at each of these
specific regions to a low level. And, at the local level, these regions
designated for inelastic activity are so detailed that they can undergo large
deformations without losing much strength and stiffness. For typical RC
frames, a strong column-weak beam (SCWB) collapse mechanism (Figure1a) satisfies the above global objective much better than by a strong beamweak column (SBWC) mechanism (Figure 1b). In SCWB systems, flexural
capacities of beams at a joint are developed before (i) the shear capacities ofthe beams themselves, (ii) the shear capacity of the joint, and (iii) the
flexural capacities of the columns.

(a)

(b)

Figure 1: Collapse mechanisms of frames (a) overall sway mechanism
owing to strong-column weak-beam design, and (b) storey swaymechanism owing to strong-beam weak-column design
Moreover, some RC frame buildings suffered damage in recent
earthquakes due to poor detailing of joint reinforcement (amount oftransverse shear reinforcement in joints and anchorage of longitudinal beambars in columns) (Rai and Murty, 2003). In the Indian context, mostbuildings were designed by the Indian Concrete Code IS:456:1978(IS:456:1978) and IS:456:2000 (IS:456:2000), in which there is no mentionof beam column joints. It is therefore important to evaluate the performanceof beam-column joints and to devise superior detailing techniques for
improved seismic behavior of lateral load resisting moment frames. Further,
the suitable retrofitting technique to rehabilitate the failed beam-column
joint in existing structures is very important to bring back the damaged
structure in its normal life.

28

New Technologies for Urban Safety of Mega Cities in Asia
360

ICUS Report 6

Extensive research work has been reported in literature on retrofittingof columns (Priestle et. al., 1996, and Seible et. al. 1997). Circular, square,and rectangular bridge columns have been strengthened externally using
continuously wrapped carbon FRP (CFRP) composites and steel jacketing.
Confinement, ductility, and shear effects were studies and design guidelines
were developed.
An experimental investigation was conducted by
Sadatmanesh et. al. (1996) to study the effect of retrofitting using composite
straps on seismic performance of RC columns. The retrofitted columns had
a improved ductility (up to 6) compared to low level of ductility (1.5)
observed for specimens without FRP retrofitting. Janoes Gergely et. al.
(2000) studied the viability of carbon FRP composite for shear
strengthening of RC T-joints. The use of CFRP has increased the joints’s
shear strength greatly and in addition there was better damage control andthe joints had the minimal residual strength at the end of the test sufficientfor supporting dead loads. Malek and Saadatmanesh (1998) studied theultimate shear capacity of RC beams strengthened with web-bonded FRP
plates. Older concrete structures do not meet the modified code criteria
This paper reports the findings of two specimens of an experimental
study on retrofitting of damaged exterior RC beam-column joint subassemblages that are typical of gravity-only designed RC frames in low
seismic regions and of pre-seismic code constructions in India and manyother developing countries. Full details of all specimens tested in this series
are given elsewhere (Murty et al. 2004).
2.0 OBJECTIVES
Retrofitting of different beam-column joints damaged under reverse
cyclic testing is done by using glass fabric reinforced polymer (GFRP)
overlays. The performance of this FRP retrofitting technique is evaluatedbased on hysteretic behavior and energy absorbed under cyclic loading.
3.0 EXPERIMENTAL DETAILS
3.1 Specimen design
Two specimens of half scale RC beam-column joint sub-assemblages
were tested, one original and another retrofitted. The original specimen
represented reinforcement detailing for anchorage of beam bars andtransverse reinforcement of joint core as practiced in most RC framebuilding constructions in India (Figure 2). The anchorage in the specimen is
typical for non-seismic (gravity) frames where only tension rebars areanchored (Indian Standard Handbook on Concrete Reinforcement andDetailing, 1987). This type of anchorage is least effective against pullout instrong seismic shaking. The original specimen S1 was tested under cyclicloads up to failure as reported in a previous study (Murty, et. al., 2003). The
photograph of a typical specimen failed in joint is shown in Figure 3.

Influence of Fibre Wrap Retrofitting on Gravity Designed RC Beam-Column Joints under Cyclic Loading 29361

October 2004, Agra, India

3.2 Application of GFRP overlays
The failed joint was retrofitted by GFRP overlays (4 layers) in the
joint region after replacing the cracked concrete with fresh concrete (Figure4). The balanced weave glass fabric (area density: 350 g/m2) has been used
Cyclic
Displacement
4 bars of
20mm dia.

400

Beam

Beam
1150 mm
250

See Anchorage
Details
550 mm

250
See
Joint
Details200

6 bars of
16mm
dia.
Column200

Column400

550 mm(a) Frame Geometry
Gravity
DesignAnchorage

No Joint
Reinforcement

600(b) Anchorage Details(c) Joint Details

Figure 2: Geometry and reinforcement details of specimen

Figure 3: The original specimen tested up to failure

30

New Technologies for Urban Safety of Mega Cities in Asia
362

ICUS Report 6

as reinforcement along with epoxy resin system for application of GFRP
overlays to retrofit all the twelve specimens damaged under cyclic testing.
The epoxy resin has two components: Resin PG-100 and Hardener PH-851
available from local manufacturer M/s Parikh Resins Limited, Kanpur. The
hardener is mixed in the resin (50% by weight) with gel time of 180-200
minutes (sufficient for retrofitting one joint at a time) and curing time of 24hours at room temperature. After cleaning the finished surface of therepaired joint a thick coat of epoxy resin was applied first. Subsequently,
layers of cut glass fabric sheets in T-shape were applied in the joint region(total four layers). The glass fabric was impregnated with epoxy resin ineach layer by using rollers and brushes so that extra resin from below comeson top ensuring proper impregnation. The cracked concrete in the beam andcolumn surrounding the joint was also covered with GFRP overlays. The
photograph of the specimen with GFRP overlays in the test set-up is shownin Figure 5.

Figure 4: Putting fresh concrete after the removal of cracked concrete fromfailed joint

Figure 5: Photograph of the GFRP retrofitted specimen

Influence of Fibre Wrap Retrofitting on Gravity Designed RC Beam-Column Joints under Cyclic Loading 31363

October 2004, Agra, India

3.3 Test set-up
The isolation of sub-assemblages from the frame structure requiresthat proper boundary conditions be simulated in the test set-up for faithfulemulation of stresses inside the test specimen akin to the prototype. A
schematic of the test-setup used in the study is shown in Figure 6. The subo
assemblage was rotated 90 such that the column member is in thehorizontal position and the beam member in the vertical position.
A 250 kN hydraulic actuator was used to apply cyclic displacements atthe beam end. The column ends are held against the reaction floor throughan arrangement, which not only restricts the horizontal movement but also
provides moment-free rotation through an external hinge fixture (Figure 6).
The loading program used was the same as for original specimens, consistedof a simple history of reversed symmetric cycles of increasing displacement
amplitudes in predetermined steps (Figure 7). At each step of loading, threecycles were performed. This simplified history permits the evaluation ofparameters such as energy dissipation potential, and failure mode, which areimportant for understanding the seismic performance of any system. The
load cell in the actuator arm measured the applied horizontal force and the
DC type LVDTs mounted on the specimen monitored the displacements andwere recorded online on a data acquisition system.
Actuator

LVDT

LVDT
Beam

Specimen

Reaction
Frame

LVDT
Column

Displacement Excursion (mm)Figure 6: Test set-up for cyclic displacement loading of joint sub
assemblage in a 90 rotated position
100
80
60
40
20
0
-20
-40
-60
-80
-100

Figure 7: Cyclic displacement loading history applied on joint subassemblages

32

New Technologies for Urban Safety of Mega Cities in Asia
364

ICUS Report 6

4.0 RESULTS AND DISCUSSIONSThe effect of retrofitting using GFRP overlays for twelve different RC
beam column specimens damaged under cyclic loads (Murty et. al., 2003)
has been studied. The retrofitted specimen has been tested under same
cyclic loading like original specimen. The overall hysteretic behavior of thetwo specimens is summarized in Table 1 and Figures 8 and 9. In general, theretrofitted specimen has been able to regain its original strength. The
specimen failed at the same displacement excursion levels as the original
undamaged specimen. The increase in peak load is between 33.7% as
observed from envelope backbone curves (Figures 10) for the specimens.
Observed pinched hysteretic curves (Figures 8-9) of the sub-assemblages(for both original and retrofitted specimens) are primarily due to premature
shear failure of the joint region exhibiting performance of joint
reinforcement.
Comparing hysteretic loops (Figures 8-9) and envelope backbone
curves of the specimens (Figures 10), the ultimate displacement (thedisplacement at 15% drop of peak load) is 20.0 mm for original specimen
and 18.1 mm for retrofitted specimen. The cumulative energy dissipatedduring the hysteretic loops has been plotted for different specimens inFigure 11 and the total cumulative energy values are given in Table 1 tocompare the performance of different specimens. A comparison of theenergy dissipation of the specimens (Figure 11) shows that the specimen
with no joint reinforcement indicates the poor energy dissipation potential.
It has been observed that use of GFRP overlays for retrofitting has been able
to achieve the original strength and marginally increase the energy
dissipation characteristics. However, there is no improvement in theductility.
Table 1: Comparison of observed Ultimate displacement and load, andcomputed cumulative energy dissipated during hysteretic cycles
Specimens

Ultimate
Displacement
u, mmUltimateLoad,Pu, kN(1)
S1
S1_Ret

(2)
21.0
18.1

(3)
70.6
94.4

Total Energy
dissipated inhysteretic cycles,
Ecummu, kN-m
(4)
5.90
7.55

ACKNOWLEDGMENTS
The experimental study reported in this paper is conducted at theStructural Engineering Laboratory, Indian Institute of Technology Kanpur(India). The untiring efforts of N. Satyanarayana, (Technical Officer),
Snehal Kaushik (Senior Project Associate), and staff members of the

Influence of Fibre Wrap Retrofitting on Gravity Designed RC Beam-Column Joints under Cyclic Loading 33
365

October 2004, Agra, India

Lateral Load, kN

laboratory in the timely completion of the experiments are sincerely
acknowledged.

100
75

S1

50
25
0
-80

-60

-40

-20-25 0

20

40

60

80

-50
-75
Displacement Excursions, mm-100

Figure 8: Lateral load-displacement hysteresis loops of original subassemblage specimen

100
Lateral Load, kN

75

S1_Ret

50
25
0
-80

-60

-40

-20-25 0

20

40

60

80

-50
-75
-100
Displacement Excursions, mm
Figure 9: Lateral load-displacement hysteresis loops of retrofitted subassemblage specimen

34

New Technologies for Urban Safety of Mega Cities in Asia
366

Lateral Load, kN

ICUS Report 6

125
100
75
50
25
0
-25
-50
-75
-100
-125

S1
S1_ret-10 -80 -60 -40 -20 0 20 40 60
0
Displacement Excursions, mm

80 100

Cumulative Energy (kN-m)

Figure 10: Comparison of envelope backbone curves (original andretrofitted specimens)

8
6
S1

4

S1_ret

2
0
0

500

1000

1500

Cumulative Displacement (mm)Figure 11: Comparison of energy dissipation
REFERENCES
Gergely Janos, Pantelides Chris P., and Reaveley Lawrence D. 2000. Shear
Strengthening of RCT-Joints using CFRP Composites. Journal of
Composites for Construction, ASCE, 4(2), 56-64.
Indian Standard Handbook on Concrete Reinforcement and Detailing 1987.
(SP 34(S&T):1987), Special Publication, Bureau of Indian Standards,
New Delhi.

Influence of Fibre Wrap Retrofitting on Gravity Designed RC Beam-Column Joints under Cyclic Loading 35367

October 2004, Agra, India

Indian Standard Plain and Reinforced Concrete Code of Practice, (IS456:2000), Bureau of Indian Standards, New Delhi, India, July 2000.
Malek A.M., and Saadatmanesh, H. 1998. Ultimate Shear Capacity of RC
Beams Strengthened with Web Bonded FRP Plates. ACI Structural
Journal, 95(4), 391-399.
Murty, C. V. R., Rai, D. C., Bajpai, K. K., and Jain, S. K., 2003.
Effectiveness of Reinforcement Details in Exterior Reinforced Concrete
Beam-Column Joints for Earthquake Resistance. ACI Structural Journal,
100(2), 149-156.
Murty, C. V. R., Rai, D. C., Bajpai, K. K., and Jain, S. K., 2004.
Effectiveness of Fibre Wrap Retrofitting on Exterior RC Beam-Column
Joints for Earthquake Resistance. Submitted to ACI Structural Journal.
Nilsson, I.H.E., and Losberg, A. 1976. Reinforced Concrete Corners andJoints subjected to Bending Moment. Journal of Structural Div. ASCE,
102 (ST6), 1229-1254.
Priestley, M.J.N., Seible F., and Calvi, G.M. 1996. Seismic Design andRetrofit of Bridges. Wiley, New York.
Priestley, M.J.N., Seible F., MacRac, G.A., and Chai Y.H. 1997. Seismic
Assessment of the Santa Monica Viaduct Bect details. ACI Structural
Journal, 94(5), 513-524.
Rai, D.C., and Murty C.V.R., 2003. North Andaman (Diglipur) Earthquakeof 14 September 2002. Reconnaissance Report, Department of Civil
Engineering, IIT Kanpur, April 2003.
Saadatmanesh, H., Ehsani, M.R., and Jin, L. 1996. Behavior of Concrete
Columns Retrofitted with Fiber Composite Straps under Cyclic Loading.
Proc., Ist International Conference on Composites in Infrastructure, 842856.
Seible, F., Priestley, M.J.N., Hegemier, G.A., and Innamorato, D. 1997.
Seismic Retrofit of RC Columns with Continuous Carbon Fiber Jackets.
Journal of Composites for Construction, ASCE, 1(2), 52-62.

36

New Technologies for Urban Safety of Mega Cities in Asia
368

NEW CONCEPT FOR RETROFITTINGCONCRETE STRUCTURES WITH
UNCONVENTIONAL MATERIALSUEDA TAMON
Hokkaido University, Sapporo, Japanegpsee@eng.hokudai.ac.jp
ABSTRACTThis paper presents some new concepts for retrofitting concrete
structures. These concepts can be recognized as new due to the facts thatmaterials other than steel, which is a truly conventional reinforcement
material, possess quite different mechanical properties and the bond of
retrofitting materials to concrete is quite different from conventional steel
reinforcement embedded in concrete.
The first concept is an application of material with small stiffness but highfracturing strain. In order to assure high deformability with concrete members,
reinforcement material should have a high fracturing strain otherwise concrete
deformability cannot be utilized fully. Low stiffness can be compensated byproviding more material, however low fracturing strain cannot. Reinforcement
materials with lower elastic modulus than steel can be more effective than steel
reinforcement if developed strain in the reinforcement at member’s ultimate
deformation is significantly higher than the steel yield strain. This is because thesteel stiffness at the ultimate deformation could be less than that of those materials.

The second concept is an application of soft adhesive for bonding
reinforcement externally. For reinforcement embedded in concrete, it is notnecessary to consider adhesive for bonding, however external bonding,which is a typical retrofitting method, must have adhesive for bonding.
Mechanical properties of adhesives are not of primary interest in the past.
In fact adhesive properties affect mechanical properties of members after
retrofitting. Soft adhesive decreases member stiffness but increases ultimate
member strength.
This paper presents experimental evidences of the above concepts as well as
numerical models to express the advantages of the new concept.

1.0 INTRODUCTION
In the 20th century human beings had accumulated so many
infrastructures, especially in mega cities. During the 21st century humanbeings must maintain those infrastructures not only for safety reason but
also for conservation of resources and energy. As a major remedial action
for maintenance, retrofitting is one of the primary interests to civil engineers.
Retrofitting methods vary greatly in terms of structural type andmaterial type. External bonding and over/under-laying as retrofitting needs

37369

October 2004, Agra, India
special attention different from that for monolithic structure. Many
retrofitting materials are not steel hence possess different mechanicalproperties from steel which shows yielding and a high fracturing strain.
The difference in structural type and material properties, however,bring us a new concept for material property to achieve retrofitting effects
most efficiently. This paper introduces some of the new concepts. The firstone is the importance of fracturing strain of material rather thanstrength/stiffness. The second is the soft adhesive (or bond) layer for
external bonding.
2.0 HIGH FRACTURING STRAIN FOR ACHIEVING DUCTILITY
2.1 Stress – strain relationship of various fiber sheets
Generally a material with a high strength shows a high stiffness but
low fracturing strain. Figure 1 illustrates stress – strain relationships ofvarious fiber sheets. Carbon is known to be a high strength and stiffness
material. The stiffness is as high as steel, and the strength is ten times ofsteel. However, the fracturing strain is around 1.5 %. Polyacetal fiber(PAF), polyethylene terephthalate (PET) and polyethylene naphthalate(PEN) show a much lower strength/stiffness than carbon but a much higher
fracturing strain (see Table 1). PAF sheet jacketing as seismic retrofittingshows a good performance to enhance ultimate ductility and even shear
strength (Ueda, 2001).
In this paper experimental evidences onenhancement of ultimate ductility with PET and PEN are presented.

Figure 1: Stress – strain relationships of various fiber sheets
2.2 Outline of experiment
Ten specimens were prepared in order to see ductility enhancement by
the duplex fiber sheet jacketing of reinforced columns. The DFS jacketing
applies two types of fiber, one of which is applied in hinge zone for ductility
enhancement and the other is in zone above the hinge zone for shear
strength enhancement. The former is PET, PEN or aramid 1 (Technora)

38

New Technologies for Urban Safety of Mega Cities in Asia
370

ICUS Report 6

whose fracturing strain is rather high, while the latter is aramid 2 (Kevlar)
whose stiffness is rather high. The details of materials used and specimens
are shown in Table 1 and 2 respectively. All the specimens were subjected
to reverse cyclic loading with a loading system as shown in Figure 2.
Table 1: Material constants


Items
Axial Reinforcement D19
Tie Reinforcement D6
Aramid 1 (Technora)
PEN
PET
Aramid 2 (Kevlar)

E (GPa)
176
188
79.5
22.6
6.7
122

fy (MPa)
394
340-

ft (MPa)
3246
1028
923
2670

 fu
0.041
0.045
0.138
0.022

Table 2: Details of specimens
Items
Unit SP-1
SP-2
SP-3
SP-4
Dimensionmm
400400
Shear span (a)mm1150
Axial load
MPa
1.0
ρ t
%
0.98
ρs
%
0.16
My
kNm
257
Mu
kNm
327
Vu
kN
284
Vc
kN
118
Vs
kN
73
(Vc+Vs)/Vu
0.67
Sheet reinforcement above plastic hinge zone
Material type
KevlarKevlar Kevlar
ρf
%
0.097
0.097
0.097
Vf
kN
231
231
231
(Vc+Vs+Vf)/Vu
0.67
1.48
1.48
1.48
Sheet reinforcement on plastic hinge zone
Material types
Technora
PEN
PET
ρf
%
0.126
0.382
0.377
Vf
kN
213
205
181.6
(Vc+Vs+Vf)/Vu
0.67
1.42
1.39
1.31
Ductility (Exp)
4.9
11.8
12
13.7

New Concept for Retrofitting Concrete Structures with Unconventional Materials
371

SP-5

Kevlar
0.048
134
1.14
PET
0.187
90.8
0.99
7.9

39

October 2004, Agra, India
Table 2: Details of specimens (Continued)
Items
Dimension
Shear span (a)Axial load

 t
 s

Unit
mm
mm
MPa
%
%
kNm
kNm
KN
KN
KN

SP-6

SP-7

SP-8
400*400
1500
1.0

0.98

SP-9

SP-10

1.18

0.78

310
393
262
120

210
260
173
107

0.74

1.04

Kevlar
0.024
67
0.99

-

1.04

PET
0.125
60.5
0.97
8.8

PET
0.063
30.3
1.21
11.3

0.16

My
257
Mu
327
Vu
218
Vc
118
Vs
73
(Vc+Vs)/Vu
0.88
Sheet Reinforcement above Plastic Hinge Zone
Material Type
Kevlar Kevlar
%
0.024
0.024
f
Vf
KN
67
67
(Vc+Vs+Vf)/Vu
1.18
1.18
0.88
Sheet Reinforcement on Plastic Hinge Zone
Material Types
PET
PET
%
0.125
0.063
f
Vf
kN
60.5
30.3
(Vc+Vs+Vf)/Vu
1.15
1.01
0.88
Ductility (Exp)
8.7
7.9
6.6

Figure 2: Loading system for columns specimen

40

New Technologies for Urban Safety of Mega Cities in Asia
372

ICUS Report 6


2.3 PET sheet performance for enhancement of ductility
The load-displacement relationship of specimens SP-6 and SP7 with
PET sheet jacketing in the hinge zone are compared with that of specimen
SP-8 without jacketing (reference specimen) in Figure 3. It can be seen thatthe reduction in load carrying capacity after the peak load with increase indisplacement is much smaller in the retrofitted specimens (SP-6 and SP-7)
than in the un-retrofitted specimen. This difference is believed to be due tonon-fracture of PET sheet even after buckling of the longitudinal
reinforcement, which can confine concrete in the hinge zone (see Figure 4).

(a) Specimen SP-6 (retrofitted)(b) Specimen SP-7 (retrofitted)(c) Specimen SP-8 (un-retrofitted)
Figure 3: Load-displacement relationships

New Concept for Retrofitting Concrete Structures with Unconventional Materials
373

41

October 2004, Agra, India

Figure 4: PET sheet in hinge zone
Enhancement of ultimate ductility can be seen in the normalizedenvelope curve (P/Py-/y relationship) as shown in Figure 5. Among
specimens SP-1 to SP-5 where the shear strength to flexural strength ratio of
the specimens before retrofitting is rather low (0.67), the enhancement
effect can be seen more clearly than among specimens SP-6 to SP-10 where
the shear strength to flexural strength ratio of the specimens before
retrofitting is higher (0.74 to 1.04).

(a) Specimens SP-1 to SP-5(b) Specimens SP-6 to SP-10
Figure 5: Ultimate ductility

42

New Technologies for Urban Safety of Mega Cities in Asia
374

ICUS Report 6

The prediction formula for ultimate ductility available in a report of
the Research Committee on Upgrading of Concrete Structures with FRP
Reinforcement, (2001), which was thought to be the best fitting ofexperimental data for carbon and aramid fiber sheet, most of which show
sheet fracture at ultimate deformation. However this formula overestimatesthe observed ultimate ductility with PET sheet indicating that a new formulaneeds to be developed.
In comparison with steel reinforcement there is an advantage withfiber whose fracturing strain is high. Around ultimate deformation any tie(shear) reinforcement is subjected to a high strain, therefore stiffness of steel
is likely to be reduced significantly due to its yielding. The fiber stiffness
whose initial stiffness is smaller than steel can be greater than steel at thisstage. This implies that the fiber reinforcement can provide a higher
stiffness, so that confinement of core concrete is more efficient.
3.0 SOFT ADHESIVE RESIN
DEBONDING STRENGTHFOR

ENHANCEMENTOF

For external bonding, adhesive must be provided. However, in thepast almost no attention had been paid to mechanical property of adhesive toachieve better interface bonding characteristics.
This paper shows
experimental evidences for significant effects of adhesive on the interface
bonding characteristics and that soft adhesive is one of the means toimprove debonding strength.
3.1 Local bond stress – slip relationship and adhesive stiffness
The pullout bond test of FRP sheet was conducted as shown in Figure
6. Local bonds stress – slip relationships observed in the test are comparedamong cases of different adhesive stiffness (see Figure 7) (Dai, et al, 2005).
The initial stiffness and the peak bond stress are smaller for softer adhesive,
however ductility is much better in the case of soft adhesive. As a result,the interfacial fracture energy increases with decrease in adhesive shear
stiffness (see Figure 8).
L oa d cell
H in ges
S tee l pla tes
F R P she ets
C on crete block

Figure 6: Pull-out bond test

New Concept for Retrofitting Concrete Structures with Unconventional Materials
375

43October 2004, Agra, India(MPa)

 Average

8

All founded curves from Exp.
G a /t a =1.05GPa/m m (FR-E3P)

6

G f=1.19N/m , B=10.4m m

-1

4
2
0
0.0

0.1

0.2

0.3

0.4

0.5

0.6

s(mm)

(a) Adhesive with a high stiffness
(MPa)

All found curves from exp.
Present m odel
G a /t a =0.49GPa/m m (SX-325)

86

G f =1.54N/m m ,B=5.77m m -1

4
2
0
0.0

0.1

0.2

0.3

0.4

0.5

0.6

s(mm)

(b) Adhesive with a medium stiffness

(MPa)

8

All found curves through exp.
Present modelG a /ta =0.20GPa/mm(CN-100)

6

G f=2.10N/mm, B=2.74mm

-1

4
2
0
0.0

0.1

0.2

0.3

0.4

0.5

0.6

s(mm)

(c) Adhesive with a low stiffness
Figure 7: Effect of adhesive stiffness on local bond stress – slip curve

44

New Technologies for Urban Safety of Mega Cities in Asia
376

ICUS Report 6



1.0
0.9
0.8
0.7
0.6
0.5



0.023
' 0.236
Gf /fc/(Eftf)



0.4
0.3
0.2
0.1
0.0

Present exp.
Regressing line
-0.352 ' 0.236
0.023
Gf=0.446(G a/ta)
fc(Eftf)
0.2

0.4

0.6

0.8

1.0

1.2

Ga/ta(GPa/mm)

Figure 8: Effect of adhesive shear stiffness on interfacial fracture energy
The bond stress – slip model (   s ) based on sheet strain – slip
relationship at loaded end (Dai, et al, 2005), shown in equation (1), canpredict the effects of adhesive stiffness very well (see Present model in
Figure 8).

  A 2 BE f t f exp( Bs)(1  exp( Bs))
where

A

2G f
Eftf

B  6.846( E f t f ) 0.108 (G a / t a ) 0.833

(1)
(2)
(3)

and G f is interfacial fracture energy, E f and t f are elastic modulus andthickness of FRP sheet, and G a and t a are shear modulus and thickness ofadhesive.
3.2 Enhancement of Debonding Strength of Beam with Flexural
Strengthening by Soft Adhesive Resin
Ultimate strength of beam with external bonding of carbon fiber sheet
can be increased by applying soft adhesive resin because of improvement ofinterfacial fracture energy as described in 3.1.
Figure 9 shows thecomparison of load – deformation relationship of strengthened beams. All
the strengthened beams show greater ultimate loads than the unstrengthened one (SP-C0). In all the cases of one, two and three layers ofsheet the ultimate loads with soft adhesive layer are greater than those
without soft adhesive layer (Ueda, 2002).

New Concept for Retrofitting Concrete Structures with Unconventional Materials
377

45

October 2004, Agra, India

Applied load (kN)150

1 layer

3 layers

2 layers

100
with soft layer
w/o soft layer

50
SP-C0

0
0

10

20

30

40 0

10

20

30

40

0

10

20

30

40

50

Deformation (mm)Figure 9: Load – deformation curves of beams strengthened by carbon
fiber sheet with soft adhesive layer
4.0 CONCLUSIONS
Through retrofitting technology, which utilizes structure and material
types different from the ordinary newly constructed structures, newmechanical concepts for reinforcing concrete can emerge. Two examples:high fracturing strain rather than high strength/stiffness and soft bonding
layer, are introduced with experimental evidence. It is hoped that these newconcepts could widen selections of structure and material types for practicaluse.
ACKNOWLEDGEMENTS
The author is grateful to Mr Hadiyono Jaqin and Dr Dai Jianguo for
their efforts in carrying the studies whose results are used in this paper.
REFERENCES
Dai J. G., Ueda T. and Sato Y, 2005. Development of the Nonlinear Bond
Stress-slip Model of Fiber Reinforced Plastics Sheet-concrete Interfaces
with a Simple Method. Journal of Composites in Construction, ASCE (tobe printed).
Research Committee on Upgrading of Concrete Structures with FRP
Reinforcement, 2001. Guideline on Upgrading of Concrete Structureswith FRP Sheet. Concrete Engineering Series 41, JSCE.
Ueda T., 2001. Bond behavior and seismic retrofitting effect of polyacetal
fiber sheet. FRP Composites in Civil Engineering. Proceedings of theInternational Conference on FRP Composites in Civil Engineering, Vol
2, 1041-1050.
Ueda T. and Sato Y., 2002. New Approach for Usage of Continuous Fiberas Non-Metallic Reinforcement of Concrete. Structural Engineering
International 12-2, IABSE, 111-116.

46

New Technologies for Urban Safety of Mega Cities in Asia
378

SIMULATION OF PLATE BEHAVIOUR
UNDER NON UNIFORM WIND LOADSTIJO THOMAS1 AND PRADEEP KUMAR RAMANCHARLA2
1
Former Graduate Student, 2Assistant Professor & Coordinator
IIIT Hyderabad, India
ramancharla@iiit.net
ABSTRACT
Procedure for finding out wind pressure at any given location inIndian subcontinent is outlined in IS-875 Part III 1987. This procedure ismade convenient to the user by developing a tool named ‘WindSim’. An
efficient algorithm has been developed for finding out deflection, when theplate is subjected to uniform wind pressure. Finite difference method is used
to solve the equation of plate in bending. It has been observed that the windpressure varies with height. Hence, the algorithm is further modified to takecare of the non-uniform wind loads and different support conditions. The
deflection of the plate is graphically simulated by drawing contours on a VB
GUI. The values of deflection obtained from the program can be comparedwith allowable deflection values, to check the safety of the structuralcomponent.
1.0 INTRODUCTION
The number of buildings increases year by year. So is the number ofhigh-rise buildings. The effect of wind on these buildings and its
components cannot be ignored. In many of these buildings, a major part ofits vertical components can be modeled as plates. Example being glass walls
in glazed building. When safety is a concern, behavior of these components
under wind forces can be a subject of interest. The work presented here
explains the program to simulate the linear behavior of building componentsthat can be modeled as rectangular plates. The program has two major
objectives:

To find out the wind loads at a given location in India.
To analyze the building component for deflection and simulate its
behavior.

The safety of the structural component is assured if its deflections arewithin the allowable limits. The paper gives a quick glance over theprovisions of IS 875, Part III (here after we mention this as the code) and its
programming implementation. It deals in detail with equation of plate inbending, finite difference method, the algorithm for numerical simulationand the behavior of plate for different boundary conditions.

157
379

October 2004, Agra, India
2.0 BRIEF OVERVIEW ON THE PROVISIONS OF IS 875-PART III
2.1 Basic wind velocity
Basic wind velocity (Vb) is the speed of wind based on peak gustvelocity averaged over a short time interval of about 3 seconds andcorresponds to mean heights above ground level in an open terrain. The
code provides basic wind speeds worked out for 50-year return period. Thisis applicable for 10 m heights above mean ground level for different zonesof the country (Figure 1).
2.2 Risk coefficient
The risk coefficient (k1factor) is dependent on the design
life of the structure and the basic
wind velocity. The k1 factors fordifferent class of structure are
given in the Table-1 of code.
2.3 Terrain, height andstructure size factor
The code has classified theterrain into four categories with Figure 1: Basic wind velocity (IS875, part 3)
regard to the effect of
obstructions that constitute the ground surface roughness. The terrain
categories are as discussed below.
Category – 1: Exposed open terrain with no obstruction and in which theaverage height of any object surrounding the structure is lessthan 1.5 m.
Category – 2: Open terrain with well-scattered obstructions having heights
generally between 1. 5 to 10 m.
Category –3: Terrain with numerous closely spaced obstructions having thesize of building structure up to 10 m in height with orwithout a few isolated tall structures.
Category-4: Terrain with numerous large high closely spaced obstructions.
The structures are classified further according to following threeclasses depending up on their sizes:
Class A: Structures and/or their components whose maximum
dimension is less than 20 m.
Class B: Structures and/or their components whose maximum
dimension is between 20 and 50 m.
Class C: Structures and/or their components whose maximum
dimension is greater than 50 m.
The table relating k2 factor to terrain category, class and height of thestructure is given below Table-2 of the code.

158

New Technologies for Urban Safety of Mega Cities in Asia
380

ICUS Report 6


2.4 Topography factor
The effect of topography is to accelerate wind near the summits ofhills or crests of cliffs, escarpments or ridges and decelerate the wind invalleys or near the foot of cliffs, steep escarpments, or ridges. The effect of
topography will become significant only when upwind slopes (ө) are greaterthan 3 degrees. When ө is less than 3 degrees, topography factor k3 is taken
as 1. If the slope is more than 3 degrees the value of k3 is obtained from thefollowing expression:
k3 = 1 + Cs

(1)

Where, C = 1.2 (z / L), when 3º < ө ≤ 17º= 0.36
when ө>17º
Here,
L = horizontal distance of the slope
Z = effective height of the feature

And for finding value of s, please refer the code.
2.5 Design wind pressure
The code provides us with the following formula for calculating the
Design wind pressure:Pz = 0.6 Vz2(2)
Where Pz = Design wind pressure
Vz = Design wind velocity
Design Wind Velocity:(Vz) = Vb k1 k2 k3(3)

The pressure coefficients are provided in the code, which when multipliedwith Pz gives the normal wind pressure on a surface.
3.0 PROGRAMMING IMPLEMENTATION
The program displays the map of India as shown in figure 1. The user
is prompted to click on the map corresponding to the location of his
structure. The basic wind velocity, obtained by sensing mouse click is
modified to get the design wind velocity as demonstrated later in this paper.
By clicking an appropriate button, user is entering the design life of thestructure. With the values of Vb and design life of the structure in hand, thevalue of k2 is obtained from the Table 2 of the code.
To find out the value of k2 factor a form has been created, whichallows the user to select the type of terrain category where his structure
belongs to. From the main form, text boxes are provided to enter the

Simulation of Plate Behaviour under Uniform Wind Loads
381

159

October 2004, Agra, Indiadimensions of the structural component. The program accesses these values
and finds out the class of the structure. Now Table 2 of the code is made useby the program to find out the value of terrain factor k2.
Separate form has been introduced to enter the values of upwind slope,dimensions of the feature such as horizontal dimension, height. Digitizing
the graphs given in the code, data files are created for finding out s. Program
has been written to access the value of s from these files corresponding to
the values of dimensions of the feature.
3.1 Application of the design wind pressure on plate
The design wind pressure serves as the uniform force per unit area on
the plate. Using this force, the plate equation is solved to find out the
deflections at any particular node of the plate. This process is explained inlater. Wind pressure is calculated at the center of the plate and applied
uniformly.
3.2 Equation of plate bending
The equation for plate inbending is given by:
4w
4w
4w
 2


x 4
x 2 y 2
y 4

Where w = Deflection of theplate
q = Force per unit area
D = Elastic constant
Et
D=
12

q / D


Figure 2: Bending of plate under uniform loads

3(1 - n 2 )E = Modulus of elasticityt = Thickness
ν = Poisson ratio
In the analysis of plate in bending, deflection is obtained by solving
the above equation satisfying the condition at the plate boundaries. The
solution for deflection is obtained by the method of finite difference.
3.3 Method of finite differenceIn finite difference method (FDM), numerical solution of thedifferential equation for displacement or stress resultant is obtained for160

New Technologies for Urban Safety of Mega Cities in Asia
382

ICUS Report 6chosen points of the structure, referred to as nodes. This solution isapplicable to the actual continuous structure. To apply FDM at a node, thedifferential equation is replaced by finite difference expression, relating the
given node and the nodes in the vicinity of that node. This equation isequated to the applied load. When FDM is applied to all the nodes in thesame way, sufficient number of simultaneous equations for displacement or
stress is obtained. The finite difference expression at nodes near theboundary has to be modified before solving for the unknown. The following
paragraphs demonstrate how this is done for a plate.
3.4 Finite difference equations at an interior node of plate in bending

Figure 3: Biharmonic operator in central difference formThe partial differential equation presented in section 3.1 is replaced
by appropriate finite difference expression. Figure 3 shows the centraldifference approximation of the partial differential expression for an interior
node of rectangular plate. These coefficients are used in the following form
for a general interior node i(5)[Coefficients] {wi}=qi/D
wi represents the deflection at a general interior node, qi represent thepressure at a general interior node and D is the elastic constant of the plate.
Similar equations are written for all the nodes in a plate. The
coefficients of nodes at or near the boundary are modified with appropriate
boundary conditions. Next section explains the modeling of the boundary.
These simultaneous equations are written in the form of a matrix, which isthen solved to obtain deflection at each node. Algorithm for finding out
deflection of plate subjected to uniform load is shown in figure 4.

Simulation of Plate Behaviour under Uniform Wind Loads
383

161

October 2004, Agra, India
Figure 4: Flow chart of the program

3.5 Modeling of built-in edge
The deflection at all
points on a built-in edge andslope of the delflected surface
normal to the edge are zero.
The equation shown in figure
5
isthe
algebraic
w
w
 0,
 0, w  0
representation of the boundaryxycondition. Internal nodes suchas ‘A’ here are modified to
Figure 5: Built-in edge modelingtake care of the boundary
condition. For example the coefficient at ‘A’ gets added with that of ‘C’ totake care of WC=WA.
3.6 Modelling of simply supported edge
The deflection and themoment vanish at all boundary
points. Here, coefficient at ‘A’gets subtracted from that of ‘C’
to take care of WC=WA as
explained in figure 6.
3.7 Modeling of free edgeMn  0 , w  0
WB=WD=WC=0, WC= -WA

Figure 6: Simply supported edge modeling

At a free edge bending
moment at any free edge is zero and there should not be any transverse
forces. For an edge parallel to the x-axis following are the conditions.

162

New Technologies for Urban Safety of Mega Cities in Asia
384

ICUS Report 6

Free Edge
G

 2 w
 nu
y 2

B
C
A

 3w
 ( 2  nu )
y 3

J

A
H
D

B

E

C
1/hx2(WC-2WB+WA)+
nu/hy2 (WE-2WB+WD)=0

D
E

 2 w
x 2

K

Figure 10

1/2hx3(WE+2WD+2WC-WB)+(2-nu)/2hy {(WK-WD+WH)/hx2--(WK-2WD+WH)/hx2}=0



0
 3w

x 2 y 0These algebraic equations
are solved to eliminate
deflections at the external
nodes.

Figure 7: Free edge modeling

3.8 Modification for non-uniform wind pressure case
While constant pressure is applied in uniform case, pressure varying
with height is applied to for non-uniform case. To find out the force vector
for this case, the height from the bottom of each row of nodes is calculated.
Factor k2 factor for this particular height is obtained from the standard.
Using k2, design wind velocity and hence design wind pressure is modified.
In short all the nodes in any particular row are subjected to the samepressure and this pressure varies from row to row.
4.0 GRAPHICAL USER INTERFACEThe GUI as shown in figure 4.1 has been developed using Visul Basic
6.0. The VB GUI provides user with convenient means to enter theproperties of both the plate and wind. Text boxes are provided to enter
dimensions such as length, breadth and thickness and material properties


Figure 8: Graphical user interface of WINDSIM

Simulation of Plate Behaviour under Uniform Wind Loads
385

163

October 2004, Agra, Indiasuch as elasticity and poisson ratio of the plate. To enter structuralproperties such as dimensions of structure and location of the plate separate
text boxes are given. User can enter the support condion by selecting fromthe combo boxes. To enter the wind properties, forms have been provided
where in user can enter the basic wind velocity and its modification factors
by mouse click. Appropriate messages are displayed when improper values
are fed in or to in confirmation of the entered value. The main program
accesses these input values processed for the results such as deflection.
These are then displayed as text in the main form. They are then graphicallysimulted as shown in next section. Utilities such as save, print, help areprovided to assist the user further. Program provides the option of analysing
for uniform pressure or non-uniform wind pressure.
4.1 Graphical simulation of the deflection

(a) Plate with no free edge(b) Plate with one free edge(c) Plate with two free edges(d) Plate with three free edges

Figure 9: Deflection contours for different edge conditions
The deflection obtained by the procedures explained in the preceding
sections is presented in the form of banded contour map on the VB GUI. In
the contour map at different parts of the plate is represented by different
colors. In general around 10 colors are used. The red color indicates the164

New Technologies for Urban Safety of Mega Cities in Asia
386

ICUS Report 6

maximum value while pink indicates ‘0’ value of deflection. The other color
indicates deflection between ‘0’ and maximum. The contour maps for plateswith different support conditions are given below.
4.1.1 Plate with no free edge
All the edges of the plates are simply supported as shown in figure 9(a). On applying uniformly load on to 4-edge supported plate, maximum
deflection occurs at the center of the plate. This is indicated by the red color.
The supported edges shows the minimum, i.e., ‘0’ deflection. The deflection
uniformly varies from the center to the edges. Deflections at the different
part of the plates are between the maximum (Central deflection) andminimum (deflection at edges) limits.
4.1.2 Plate with one free edge
On applying uniformly load on to 3-edge supported plate as shown infigure 9 (b), maximum deflection occurs at the center of the free edge of theplate. The supported edges show the minimum, i.e., ‘0’ deflection. The
deflection uniformly varies from the center of the free edge to the supported
edges. Deflections at the different part of the plates are between the
maximum (Central deflection-shown by red color) and minimum (deflection
at edges) limits.
4.1.3 Plate with two free edges
Two edges of the plates are simply supported and two are free asshown in figure 9 (c). When uniform load is applied on to 2-edge supported
plate, maximum deflection occurs at the center of both the free edges of theplate. This is indicated by the red color. The supported edges show theminimum, i.e., ‘0’ deflection. The deflection uniformly varies from thecenter of the free edge to the supported edges. Deflections at the different
parts of the plate are between the maximum (Central deflection-shown by
red color) and minimum (deflection at edges) limits.
4.1.4 Plate with three free edges
One edge of the plate is fixed, while all other edges are free as shownin figure 9 (d). When uniform load is applied on a 1-edge supported plate,maximum deflection the center of the free edge, which has two unsupported
corners. This is indicated by the red color. The supported edges show theminimum, i.e., ‘0’ deflection. The deflection uniformly varies from thecenter of the free edge to the supported edges. Deflections at the different
part of the plates are between the maximum (Central deflection-shown by
red color) and minimum (deflection at edges) limits.

Simulation of Plate Behaviour under Uniform Wind Loads
387

165

October 2004, Agra, India
5.0 RESULTS AND DISCUSSIONS
The maximum
Table 1: Deflection of plate
deflection
obtainedfrom the analysis is
Deflection
Deflection
under uniform
undernoncompared for nonSupport
wind loads (inuniform
wind
uniform application ofConditions
mm)loads (in mm)
wind
loads
and
4-Edge Supported
4.083
4.0516
uniform application of 3-Edge Supported
12.1537
12.0569
wind loads. Values of 2-Edge Supported
14.240914.3554
the deflection for 5 X 1-Edge
5 m glass plate, Supported
66.306466.3515
located in a general building in windzone-1, has been compared in the Table 1 given above. It is found that the
deflection values are comparable. Maximum of the two deflection values
can be taken for checking the safety of the structural component. For
example, in the case of glass panels, the deflection value obtained from theprogram can be compared with the allowable deflection for standard glass
types. If the value from the program is within the allowable deflection theglass panel is safe.
6.0 CONCLUSIONSA software tool is created to find out design wind pressure at any
given location in Indian subcontinent. The GUI of the program can takemost of the input values from user through mouse click. The wind pressure
so obtained confirms to IS 875 Part III, 1987. In second part of the program,deflection of plate under the action of this force is found out. An efficientalgorithm has been developed to find out the deflection of any structuralcomponent that can be modelled as a rectangular plate. Algortihm isgeneralised to take care of different boundary condition. The algorithm issuitably modified to take care of the non-uniform wind loads. Of the two
types loading condition, one which gives the maximum value of deflection,
can be used for checking the safety of the plate. The deflection is thengraphically presented on VB GUI, in the form of banded deflection contour
map for better understanding about the plate behaviour. If the values ofallowable values of load or deflection of any material is known, the tool canbe used for checking the safety of the stuctural component.
REFERENCES
IS 875 Part 3 1987,1997. Bureau of Indian Standards, New Delhi.
A Ghali and A. M. Neville, 1997. Structural Analysis, A unified classicaland matrix approach. E & FN SPON, Taylor and Francis Group.
C. V. Girija Vallabhan, 1982. Iterative analysis of Nonlinear Glass Plates.
Journal of Structural Engineering, Vol 109, ASCE .
Tirupathi R. Chandrupatla and Ashok D. Belegundu,2002. Finite Elements
in Engineering. Prentice Hall – India.

166

New Technologies for Urban Safety of Mega Cities in Asia
388

URBAN SAFETYAND SECURITY ISSUES,CONSTRAINTS AND CHALLENGESAHEAD - AGRATAHSINUR RAHMAN WARSI1 AND ANURAG KHANDELWAL2
1
Senior Lecturer, 2Visiting Faculty, Aligarh Muslim University, India
trwarsi@rediffmail.com
ABSTRACTAgra in 1991 census has been added to the list of Mega Cities. Agrabeing synonymous with Taj, one of the most beautiful structures built by
man and is among the most visited building in the world. With a total
population of 11.5 lacks in 2001 census the city cater 8000-10000 tourists
per day. Agra being the most important landmark of India still faces thebrunt of government negligence. The issues of safety and security of Taj arefocused more than the inhabitants and citizens of Agra.
The present paper discusses the various issues and challenges related
to urban safety and security of environment, health, socio-economic andurban design parameters with reference to Agra- The City of Taj.
1.0 INTRODUCTION
Agra in 1991 census has been added to the list of mega cities. The
growth of the city with its ever-increasing population has been putting uppressure on the infrastructure available in the city, thereby challenging thecore issues of Cities Urban Safety and security. Agra synonymous with Taj
Mahal, one of the most beautiful structures built by man and today it isamong the most visited monuments in the world. This adds up to thepressure on the Available infrastructure of the city.
2.0 TAJ MAHAL- BEYOND THE LOVE STORYTaj Mahal – one of the world’s greatest architectural wonders – isunder threat. Taj situated in Agra, one of India’s most chaotic and polluted
cities, this majestic monument is gradually being consumed by fumes andchemicals emanating from vehicles, diesel generators, factories, foundries,
and refineries. The government is prepared to close these industrial units, toprotect Taj, thus threatening jobs of millions. Taj Mahal: beyond the lovestory raises a question—in a poor country like India, can protecting amonument is more important than livelihood needs?



41
389

October 2004, Agra, India





Taj Mahal

Traditional Steet - Agra
Figure 1: Scenes of Agra
3.0 AGRA–ITS DEVELOPMENT AND OVERCOMINGCONSTRAINTS
Strategically located and well connected by roads and railways to themajor town especially the capital city Delhi, the city attracts a lot of people
from the nearby by villages cities and districts for the opportunities for work,business, medical care, higher education, entertainment and shopping. Withthe total population of 1.15 million in 2001 Census, Agra attracts aminimum of 8000-10000 visitors per day and the figure during the peak canreach upto 80,000 to 100000 visitors per day.
Emperor Akbar founded Agra because of its strategic location, eversince Agra has been the hub of commercial activity. Akbar made Agra his
capital and the development of the city experienced the golden era. During
the reign of Emperor Shahjahan a feather in the cities cap was added –TAJ
MAHAL. During the British Rule, the British Lords also realized theimportance of the city and intended to make Agra the Capital, which finally
was changed to Delhi.
A network of railways was set up and Agra was made one of theMilitary bases for British Army. Its Geographical Location provided a
strategic advantage for the mobilization of the forces. Because of theinfrastructure development city always provided the opportunities for
employment and business to the people. After independence, Agra received
a large number of refugees and migrants. The Business flourished and soon
Agra became the commercial hub of northern India. Iron Foundries andBrick Kilns mushroomed after Independence. At present about 40% of thetotal economy of Agra depend on industry (Directly or indirectly). Over
7200 Small Scale Industrial Units are spared all over the district. Agra city
is famous for the Leather Goods, Handicrafts, Marvel and Stone carving &inlay work. Agra is also well known for eats sweets (Petha) and Snacks(Dalmoth & Gajak). The Leather industry grew multifold as the city dwelled
skilled labour, the specialty sweet ‘Petha’ Industry grew as the agriculture
conditions favoured the cultivation of the pumpkins. Iron Foundries favoredthe growth of allied industries of casting. Agra became the hub of Generator

42

New Technologies for Urban Safety of Mega Cities in Asia
390

ICUS Report 6and diesel pump sets, automobile spares, and moulds. Agra supported thegrowth of Glass industry of nearby town Firozabad.
Education centers groomed as the universities, Technical and Medical
institutions established to cater the vast population of the city, nearby areas
and even abroad. The abundant availability of the technical and skilled
manpower supported the industrial growth and Agra became the biggest
medical center in northern region. Nursing Homes mushroomed as thedemand for basic medical facilities to cater to the people of Agra and its
nearby towns grew leaps and bounds.
The City Agra having all the advantages of factors of growth was
not able to sustain the development and in the present state stands as an
example of among the most chaotic and polluted cities in the world havinglots of urban safety and security challenges..
4.0 INFRASTRUCTURE AND URBAN SAFETY AND SECURITY
4.1 Socio economic scenario
The City has a total population of 1.15 million and 43% population
still lives in Slums. There are 182 identified slums in Agra. These Slums arein very bad Conditions. With the Supreme Court ordering for closure of the
Polluting Units for the safety of the heritage monument viz., Iron
Foundaries, Brick Kilns, Leather processing industries, without making
provisions for alternate solutions has led to millions losing there jobs andwork. The increasing unemployment and poverty results increase in crimesin the city.
4.2 Roads
The Physical infrastructure of the city, the total length of roads ads is
142 kms. Out of which 75% are two lanes. Near about all the streets are
narrow and hinders the smooth flow of traffic, creating health hazard due tovehicular pollution. The existing road network is inadequate for bothintercity and intra city traffic movement. The vehicles are highly varied incharacter and at the same time one can observe the most basic form oftransport (Bullock Cart) to the most advanced Automobile on the streets.
The three National highways and few other highways passing through thecity further aggravate the traffic chaos. It increases the traffic volume andtraffic jams, results in increase in air pollution. The chaotic and unregulated
traffic results in road accidents.
4.3 Power
Per Day electricity deficiency is about 250 MVA and inadequatetransmission infrastructure is leading to power breakdowns. Agra Faces
regular severe power break approximately 4-6 hours per day. This has led tooperating of large number of Diesel generator sets compounding
considerable amount of air pollution.

Urban Safety and Security Issues, Constraints and Challenges ahead - Agra
391

43

October 2004, Agra, India


4.4 Water supply
Situated on the bank of river yamuna the major river of the Country,
city faces the major drinking water scarcity. The river is dry for almost ninemonths and is being heavily polluted by city and industrial waste. The watersupply from the yamuna is for only 1-2 hours per day. About 24 drains are
directly discharging effluent and sewage in Yamuna making the water
totally non potable. The fishes in yamuna in Agra died due to the fact thatthe BOD in Water has reached to zero levels. The water quality is low formost part it is having high coli form count due to breakages in pipe. Iron
content in water is exceptionally high and residual chlorine and TDS areconsiderably high. The Most of the inhabitants sustain on undergroundwater, which also has very high TDS and Salinity.
4.5 Waste and sewage
Only About 30% of the city is covered by sewerage network, the rest
still survives on the most primitive techniques of sewage system. The total
Sewerage generation of the city is 128.6 mld., there is no sewrage treatment
plant. The open drains which usually get choked by solid waste results insewerage flowing on the roads and streets. The Waste disposal facilities arealso lacking in the city. The city generates 450 tones of solid waste, which is
uncollected. The situation in the area of ‘petha’ industry is even worst. Even
the Biomedical waste of 400 odd nursing homes and clinics without being
incinerated find its way into the general garbage bins.
4.6 Air pollution
Vehicular traffic is one important source of pollution in this mega city.
The number of vehicles in Agra has increased manifold. The increase has
been characterized by boom in private transport. The total air pollution in
Agra from domestic sources, D.G Sets, Industrial sources, ‘Petha’ units andvehicular sources are 51t/day. In General the air quality is poor with SO2,
NO2 and SPM content in the air is above permissible limit.
With an Adverse Chaos and unmanaged situation the city lacks any
facilities to counter adverse situations and any calamities. The lacking basic
amenities and infrastructural facilities has made a city a dumps of Garbage
and Chaos. The Urban Safety and Security has been put to ultimate Test.
The Social and Environmental Safety and Security of its inhabitants and ofits world heritage monuments are at stake.
5.0 SUGGESTIONS
Following are some suggestions to solve above mentioned challenges:

44

The new technology for power generation and solid waste disposal,
which are eco-friendly, should be adopted.

New Technologies for Urban Safety of Mega Cities in Asia
392

ICUS Report 6












A citizens’ committee should be constituted specifically for the
improvement of heritage areas having representatives from local
residents and user of those areas.
NGOs should be provided with greater opportunities to participate
in monitoring the state of the environment and Networking
amongst NGOs in the region should be further strengthened.
Governments should ensure wider participation and empowermentof women, youth, local communities and indigenous people inenvironmental management.
Public awareness about environmental issues in Agra must be
increased. Awareness has to be managed through various
innovative means of communications in view of large illiterate
population.
Recognizes the importance of Agra as a world heritage andextends its support to the efforts being made by local communities
and NGOs to protect its beautiful environment.
Identify polluting industries in the Taj Trapezium and to suggest
measures to control such pollution, which is harmful to the Taj as
well as human being.
Governments of India need to develop and adopt pro-people andpro-environment policies.
Empirical evaluation of every problem has to be worked out tofind out their economic viable and sustainable solutions.

6.0 CONCLUSION
Agra is on tourist map of world because of ‘Taj Mahal’ one of thewonders of world. Various efforts are being made to preserve and make thismonument everlasting but unfortunately no serious attention have been
given towards safety and security of more than one million inhabitants ofthis town. Who is more important ‘human being’ or ‘Taj’? Who is reallyresponsible for this? These are some questions, which need to be answered.
In present paper various issues regarding urban safety and security incontext of Agra have been discussed. We think each and very issues may beelaborated further in order to investigate causes of various problems and to
evolve sustainable solutions.
REFERENCES
Asher, C.B., 1995. Architecture of Mughal India. Cambridge University
Press, U.K.
Carmona M., 1996. Controlling Urban Design-Part 1: A Possible
renaissance?. Oc Taner(editor). Journal of Urban Design. Volume 1,
Carfax Publishing Company UK.
Lang, J., 1994. Urban Design the American Experience. Van Nostrand
Reinhold. ISBN 0442013604

Urban Safety and Security Issues, Constraints and Challenges ahead - Agra393

45

October 2004, Agra, India


Moughtin, C., Cuesta. R., Sarris, C., and Signoretta, P., 1999. Urban Design
Methods and Techniques. Architectural Press, Great Britain. ISBN
0750641029.
Nath, R., 1997. Agra & its Monumental Glory. Taraporevala, Bombay, India.
Nath, R., 1976. Some Aspects of Mughal Architecture. Abhinav Publications,
New Delhi. India.

46

New Technologies for Urban Safety of Mega Cities in Asia
394

URBAN SAFETY IN ASIAN CITIES: FOR
THE CITY DWELLERS, BY THE
CITY DWELLERS
MAHUA MUKHERJEE
Indian Institute Technology Roorkee, Roorkee, India
mahua1965@rediffmail.com
ABSTRACT
Today’s mega-city in Asian context can be compared with dinosaur,
one of the largest ever animal on earth. Strong apprehension is there, innear future, if corrective measures are not applied to these mega-cities they
can be extinct species of human settlement like dinosaurs. Haphazard
growth pattern coupled with uncontrolled population explosion are now aserious global concern. Natural or manmade disasters make them more
vulnerable.
Policymakers, planners and programme developers are working on
war-foot to maintain and recreate a safe environment. Situation of Asianmega cities are rapidly deteriorating due to extreme shortage ofinfrastructural facilities. The very purpose of city dwelling (i.e. safety andquality living) is being defeated at every steps. Not that effort is absent; newtechnological innovation/ developments are making the process smootherand more flawless. With easy communication (physical and informatics)
sharing of experience from successful attempts are quite common today. But
until and unless the common people would be involved in the process ofproblem solving starting from analysis to implementations of decisions, thisis partly futile exercise. If the users feel changes proposed/made as worthy
to follow, practice and pass on to next generation optimal success can beachieved. The scope of researchers has to be extended beyond planning anddevelopment of physical environment and use of new technologies like GIS
etc. User’s friendly technology or planning has to be initiated to takecommon people into the wing of development process. Many important
information or research results never reach the target group. In this paper
the author explores situations which are different as bridging between
planners/policymakers/ researchers and the common city dwellers wasappropriate. Dissemination of knowledge on behalf of researchers andawareness, local governments’ effort to bridge the gap and active
participation from common city dwellers have changed the situation.

47395

October 2004, Agra, India

1.0 INTRODUCTION
1.1 Urbanization
The human settlement pattern in today’s cities is far from ideal.
Ordered planning in central cores with haphazard growths in transitionalzones is a common feature. The global imbalance in the quality of life
makes things more difficult. In developing countries the confusion ofplanning with general urban destitution is certainly severe than in thedeveloped societies. In a book of Politics, Aristotle has described theurban settlement as habitable, when it can satisfy two main requirements–
security and a good life [Gottmann, 1990]. According to him, the families
form dense settlements for purposes of defense and once security areachieved, they remained there for the sake of a good life; i.e. happinessand safety are the aims of any human settlement. The terms like ‘good
life’ or ‘happiness’. ‘Security’ and ‘safety’ are subjective- but the notion
they convey, can be easily appreciated. Cities are major contributors to thecountry’s economy and resource development. To sustain this powerfulengine of growth and development, the cities must be planned, managed
and governed soundly.
1.2 The impending crisis
Cities are places where social issues such as poverty, homelessness,
crime and unemployment are becoming more far-reaching and complex thanever before. Urbanisation compounds issues like access to safe water,transport, education, security, health services, solid waste disposal anddrainage etc. – often for the worse. One of the major challenges at the end of
this century is the need to develop practical strategies for safe quality living
in urban areas. Good governance, sustainable development and security are
indivisible. Today’s mega-city in Asian context can be compared withdinosaur, one of the largest ever animal on earth. Strong apprehension isthere, in near future, if corrective measures are not applied to these megacities they can be extinct species of human settlement like dinosaurs.
Haphazard growth pattern coupled with uncontrolled population explosion
are now a serious global concern. Natural or manmade disasters make themmore vulnerable.
1.3 Urban safety and security: a major issue in Asia
Urban areas in Asia have become the place where social
dysfunctionalities are exposed and unattended for longer time. Situation is
rapidly deteriorating due to huge pressure of population coupled withshortage of resources and infrastructural facilities. The very purpose of citydwelling (i.e. safety and quality living) is being defeated at every steps. Not
that effort is absent; new technological innovation/ developments help tomake the process smoother and more flawless. But they are not enough toensure safety in urban life. Absence of safety creates a feeling of insecurity
among inhabitants, tearing the social fabric of cities and threatening the48

New Technologies for Urban Safety of Mega Cities in Asia
396

ICUS Report 6

foundations of democratic institutions. It is not pleasant to think that one
cannot attend social events, classes in the evening, nor visit friends without
feeling afraid for one’s own safety.
World-wide, urban crime and violence is increasing. Because of therelative anonymity of city life, it becomes an attractive place for thieves,burglars, muggers, car hijackers and others, who can commit crime without
fear of recognition. The role of city governments in local crime prevention
is quite recent. Environmental degradation has also reached a new height.
Cities are gasping to ensure that air is cleaner, water purer, and plant andanimal species better conserved and protected. Better economy andimproved physical environment can provide a safe life to some extent.
When they are coupled with conducive social environment are bound toprovide quality living. In developing countries cohesive social fabric is on
the verge of collapse. Revitalisation of social link is another difficult task
for the urban authorities at present situation.
2.0 URBAN SAFETY
2.1 Purview of the issue
Urban safety has different meanings to people of different
backgrounds. For a social scientist, this is an issue which deals with crime,
violence, social exclusion, law and order, attitude towards women andchildren, active participation, social festivals etc. Economist views this asavailability and security of job, adequate compensation, healthy GDP,
growth in industry & trade. For engineers, architects and planners this isequivocal to healthy built environment, satisfactory (both qualitative &quantitative) infrastructures like road networking, water supply and drainage,
waste disposal systems etc. Environmentalist can base her judgment on
physical or natural environment. Her consideration is pollution free water,soil, air, sound etc; conservation of vegetation cover, water body, and above
all bio-diversity conservation. Medico thinks in terms of medical safety i.e.
healthcare facilities in quantitative or qualitative terms or both. For the
Political leaders this is a question of healthy electoral process, control or
instigation of conflicts, ethical power play. Government assesses safety interms of prevailing law and order situation, prevention and control in crimeand violence, poverty eradication, abolition of social exclusion, control ofsocio-politico-religious turmoil, establishment of corruption-freeadministrative and judiciary process. Mitigating emergency situation due tonatural hazards or man made disaster is another important task forgovernment.
Public safety and security is increasingly recognised as a key
planning and management objective to ensure economic and social
development, as well as a central aspect of the quality of life. Public security
must be considered as a public good for social well-being to be promoted bypublic institutions and civil society together. The measures to protect
communities from deprivation, unemployment, homelessness and injusticewill also protect them from crime and violence. High crime rates are

Urban Safety in Asian Cities: for the City Dwellers, by the City Dwellers
39749

October 2004, Agra, India

attributable to causes like [United Nations- Safety for All,1998]: disparity
between income and expectations; the exclusion of youth; violence as ameans of solving conflict within homes and communities; poorly designed
and secured property; easy access to firearms, alcohol and drugs; andincreasing impunity and unaccountability
Road Accidents are currently ranked as the eighth biggest cause of
fatalities in the world and it is predicted that by 2020 they will be the thirdlargest cause of death [The Institution of Highways and Transportation
Guidelines, 2004]. As well as economic costs, there are social costs in termsof pain, grief and suffering caused to road accident victims and their friends
and relatives. A large proportion of road accidents take place in urban areas;
this is because urban areas are more complex than rural ones and there ismore potential for conflicts to occur. Motor vehicle traffic levels in Asia
have grown substantially over the last 30 or so years and these levels are set
to keep rising. As the number of vehicles and distance traveled increases,
there is a greater chance of conflicts occurring on the road and therefore
potentially more road accidents.
Political conflicts in countries prevent the suitable development of
cities and the provision of security to citizens. Government must also work
towards preventing the conflicts which make crime prevention that muchharder, while envisioning strategies for urban crime prevention. Only
through these measures can the proper development of cities and thestability of countries be assured. Many African cities are examples of what
happens when the governing framework collapses or does not exist. Citizens
become victims of poverty or civil war. Crime becomes rampant in the wakeof population displacements, illegal weapons and economic need.
Urban Safety and Disaster Mitigation Division in government level
will develop management technologies to ensure the structural safety ofurban infrastructure from natural disasters such as earthquake, flood, etc.,
and their safety for use at the time of disaster.
2.2 Methods of control
Urban crimes are of different hues – alcohol, drug abuse, petty or
violent crime (murder, rape, and molestation), theft, dacoity, trade in womenand children, neglect & insecurity of elderly people and children, crime
against school children etc. Prevention and reduction of crime is now being
ensured with better training of police force, improved communication
systems, use of sophisticated instruments etc. Crime information, role ofnational as well as local governments, the police and judiciary, communities
and partnership, monitoring and implementation of programme everything
plays important role to curb crimes.
In many Asian countries the road accident trend has been towards
control in fatalities even though there have been continued increases invehicular and pedestrian traffic levels. This has been a function of50

New Technologies for Urban Safety of Mega Cities in Asia
398

ICUS Report 6transportation engineering and traffic management, education, enforcement
and increases in safety standards. There are many well-documented methods
which can be used to make urban areas safer, including traffic calming,
zoning according to speed etc. Road engineers have the solution to many ofroad safety problems, but they are not always implemented as widely as
they could be. The reason is often that the public opinion and/or politicalsupport are missing.
Recent rapid development of information technologies, i.e., Internet,
Mobile Computing, Remote Sensing, Virtual Reality, etc., have changed oursocial life in various fields. Government, both at national and local levelaims to develop and evaluate technologies for monitoring information ofurban infrastructure, ensuring their safety for daily use and in case of
emergency. This remarkable innovation also affects the field of urban
safety planning or disaster mitigation. Cooperating with these latest
information technologies, some human activities for disaster mitigation
could be shifted into a new paradigm. Especially, GIS technology will be aneffective means, because the spatial viewpoint is indispensable not only forthe field of physical environment like urban planning but also for humanactivities. In fact, a lot of researches with GIS have been carried out e.g.
MUSE (the Method of Urban Safety Analysis and Environmental Design) toanalyze a city from the viewpoint of urban safety [Murao and Yamazaki,1999]. City safety and disaster prevention strategy includes engineering
technique for utilization of earthquake-predicting information.
2.3 Limitations
Safety and security have been identified as priority areas of urban
development policies. In reality, responsibilities for these subjects belong todifferent institutions, which are dependant of various Authorities operating
at different levels. In many cases they do not share any compatible platform
to exchange information, knowledge or experience. Though theoretically,
with easy communication (physical and informatics) system of present day,sharing of experience from successful attempts are not difficult. This showsthat the creation of partnerships which are sometimes complex, is always
necessary. Enforcement of safety is faced with a multitude of challenges
including high rates of delinquency, violence and insecurity; fears andconcerns of the public; lack of faith in the efforts of the police to combat
crime; frustrations with criminal justice systems; scarce government
resources to cope with crime; and the inherent risk to democracy andeconomic development if sustainable solutions to crime are not found.
Participation of common people in the process of problem solving
starting from analysis to implementations of decisions will make it a good
exercise. If the users feel changes proposed/made as worthy to follow,
practice and pass on to next generation optimal success can be achieved.
The scope of researchers has to be extended beyond planning anddevelopment of physical environment and use of new technologies like GIS
etc. Many important information or research results never reach the target

Urban Safety in Asian Cities: for the City Dwellers, by the City Dwellers
399

51

October 2004, Agra, India

group. User’s friendly technology or planning has to be initiated to takecommon people into the wing of development process. Limitation of
resource may be a problem for Asian cities; but the experience from unsafe
cities of developed countries counterbalance the issue of resource
availability for ensuing safety; and reinforces the argument in the favour ofpublic participation.
3.0 COMMUNITY’S PARTICIPATION
3.1 Community and safety
To make a safer world there should be a common vision. Such avision has two components: a vision of what is wanted; and a plan of action
for viable strategies that are implementable. This vision should include
educating people, motivating them based on their education and organisingfrom a planned, central body. Such a vision must incorporate long and shortterm goals, and should be partnership-focused. In addition to vision, morepractical information must also be gathered. Given these diverse causes,
solutions must go beyond law enforcement and criminal justice toincorporate prevention. A prevention focus should include: potential victims,
persons and families at risk, as well as the general public, who should be
encouraged to promote collective and individual responsibility to discouragea culture that fosters crime.
Crime prevention programmes are most likely to be effective if
developed locally (and not at national level), drawing in local players andlocal government. For crime prevention to succeed, it must involve thecommunity it is meant to help, because crime flourishes when good people
do nothing. Community involvement needs to be interactive and must be
inclusive – everyone who wants to participate should be allowed to.
The traditional criminal justice institutions can no longer stop or
control the escalation of urban violence. Today, reducing crime iseveryone’s responsibility: local authorities, Habitat, and key local actors
working together in partnership. If we learn to take responsibility and action,
our cities can be places where life is led in dignity, safety, happiness andhope.
Psychological pressure can be fought in groups. All are aware thatpeople cannot deal with urban violence and insecurity by repression alone.
One need to focus on prevention and awareness-building withincommunities to address the root causes of urban violence. ‘Partnership’ isthe current buzz-word, but for it to become a sustainable alliance it must be
based on equality and on the differing economic, social and politicalrealities of our world. Information sharing becomes important in this regard.

52

New Technologies for Urban Safety of Mega Cities in Asia
400

ICUS Report 6

3.2 Scope of community participation
Based on experience in the Safer Cities programmes [UNCHS, 1995],
preventive policy should be implemented and coordinated at the city level,
while political guidance, monitoring and evaluation are performed bynational government. The experience from implementation of suchprogrammes in several cities across the globe is quite exploring. Both atnational level and at local level following steps can be followed to combat
urban insecurity. At national level:






Improve socio-economic policies affecting excluded groups,
particularly youth and those in urban areas;
Create national responsibility centers for crime prevention;
Increase safer city programmes;
Engage public support; andPursuit of strategies that have been effective world-wide.

At local level:







Evaluate the process identification of existing problems (crime,
drugs, quality of life);
Verification of problems through analysis;
Identification of who is affected by these problems and whoshould be involved in their resolution;
Establishment of a community policing philosophy engaging all
key stakeholders;
Initiation of community mobilisation strategies;
Establishment of realistic, manageable and measurable goals.

There are common challenges facing cities both in developed anddeveloping countries. Notably, justice systems often function inadequately –or worse, not at all. The justice system is in crisis as a result of the increasein crime. The large amounts of money spent on fixing justice systems incountries around the world have not always improved the functioning ofthese systems. What is needed is a system that can assist policing which
involves the role-players who are close to the situation in the community.
3.3 Appreciable efforts
Throughout the globe persisting strong efforts are there to make thecommunity equipped to ensure safety and security in their urban settlement.
In the following paragraphs few of these examples have been cited. Most of
the efforts have been initiated in Europe and USA.
In Côte d’Ivoire in Africa, thousands of refugees from Liberia haveentered the country. While government policy has been to incorporate thesepeople into the country, there have been repercussions from the massive
growth of urban areas. For example, transmissions of communicablediseases and crime have increased and weapons and drug trafficking is in

Urban Safety in Asian Cities: for the City Dwellers, by the City Dwellers
40153

October 2004, Agra, India

evidence. Thus, the need for a framework of public-private partnerships
becomes all important and government is working on it [United NationsSafety for All,1998]. In Europe, several cities have undertaken safer city
approaches to reduce crime. These programmes have made use ofpartnerships and co-operation exchanges which allow for the shaping ofexperiences and the sharing of best practices. In San Francisco of USA,
Urban Safety Programs [Urban Safety Programs] has been created to make astatement and to combat the feeling of resignation (towards accepting that
violence or crime may occur to anyone). One should not have to feel
resigned, nor do they have to harbor a deep seated anger. It is possible toface these issues squarely, and do something through Martial arts.
Alternative community court can take care of less serious crime,
local byelaws violation, family or neighbourhood disputes etc. This canprovide relief to people from waiting lifetime to get justice. Punishment canbe awarded as different community services depending on the degree ofseriousness of the crime. In Singapore this is a common practice and it’seffective too.
In 1996, the Towards World Change conference was held in
Vancouver, Canada. The conference was built around the notion that crime,
human rights and equality are closely related and that crime flourishes in theabsence of the other two. Three main tracks were identified: cities andcommunities, social development and justice. All require the involvement of
key role-players in order to bring about crime reduction. The conference
resulted in an action plan which encouraged the strengthening of theInternational Network of Practitioners, exchange of best practices, national
support and the holding of a second international conference inJohannesburg in 1998. The resulting International Crime Prevention Action
Network (ICPAN) operates as a forum for the development and exchange ofideas, strategies, resources and training at the community level.
Urban Safety Management [DUMAS] is a structured approach toaccident prevention and casualty reduction on urban roads introduced by
European Commission. Deaths, injuries and damage in accidents on urban
roads, and people's apprehensions about traffic risk in towns and cities canbe reduced by applying the principles as developed in the programme. Local
Area Safety Schemes like a roundabout, road humps, cycle lane, a bend in aroad, can reduce accidents. Strategy to make it successful has been
identified as consultation with local people & groups of people withmobility handicaps; acceptance of measures; evaluation of proposed
schemes; implementation and monitoring; monitor progress towards safety
objectives for a whole urban area etc. As conditions in urban areas areconstantly changing, the safety management strategy should be kept
continually under review. Objective Urban Safety [Objective Urban Safety]
has been introduced in USA to boost confidence to live & work in officesafely. Suggestions are to avoid becoming the victim by varying routine/
lowering the profile/ playing the 'chameleon' / recognising the danger signs/staying aware; getting about safely by on buses / the underground and54

New Technologies for Urban Safety of Mega Cities in Asia
402

ICUS Report 6

trains /taxis, by car and on foot; protecting possessions like wallets, purses,
handbags, credit cards, mobile telephones, cars; and protection at homethrough on the telephone - nuisance calls etc, answering the door, rules
about keys, during a break-in, fire, security of the home etc.
In urban India, efforts are to induct school children in the safety
awareness and implementation schemes at young ages. School children
observes traffic weeks, taking training to learn self defense, improving
interactions within neighbourhoods, taking care of elderly people etc. It is
too early to assess the impact of these initiatives.
4.0 COMMENTS
The city authorities in Asia have begun to recognise the scope of the
problem and are working towards proactive safety policies. Following EU
countries, safety is on the political agenda of municipal elections and moves
are being made to make lives safer. However, every city has its own
priorities and accordingly set their target and deduces the policy for
implementation. To be able to provide a safe and secured environment local
governments and communities can work together with following targets: Ensuring efficient performance of municipalities throughsatisfactory service delivery functions; The creation or rebuilding of local networks;
 Hauling up of local economic activities to revitalize thecommunity Introducing alternative judiciary system to make judiciary
process faster and issuing pro-neighbourhood punishments.
 The promotion of environmental design that stimulates
community interactions, using simple indicators for assessment
which community people understands;
 The need to prevent social exclusion.
The successful undertaking of these measures will prepare Asians foran urban 21st century. In developing a capacity-building strategic plan,
focus should be on priorities such as communities’ abilities to assess andmanage crimes of concern, undertake pollution prevention, participate inbiodiversity conservation, and improve economic and social efforts.
REFERENCESDUMAS, Urban Safety Management Programme. European Commissions
on Safety. http://www.trl.co.uk/dumas/index.htm
Gottmann Jean, January 1990. Political problems of Urban Growth. Guest
Editor’s introductory statement, Ekistics, No. 340-341.
The Institution of Highways and Transportation, Urban safety management
guidelines.
http://www.dft.gov.uk/stellent/groups/dft_roads/documents/
page/
dft_roads_504781.hcsp.
Murao, O., and Yamazaki, F., 1999. Use of GIS for the Method of Urban

Urban Safety in Asian Cities: for the City Dwellers, by the City Dwellers
403

55

October 2004, Agra, India

Safety Analysis and Environmental Design. Proceedings of the 20th
Asian Conference on Remote Sensing, Vol. 2, 951-956, Hong Kong.
Objective Urban Safety. http://www.objectiveurbansafety.com/
Urban Safety- Safety for All. Report of the International Conference for
Crime Prevention Partnerships to Build Community Safety. 26-30
October 1998, Johannesburg South Africa, Edited by Sarah Meek,
assisted by Kirsten Bowen-Willer.
United Nations - UNCHS, Safer City Programmes, 1996. http://www.
unchs.org/safercities.html.
Urban Safety Programs. http://www.angelfire.com/ca/usp/

56

New Technologies for Urban Safety of Mega Cities in Asia
404

PER-FIELD CLASSIFICATION OF INDIAN
URBAN ENVIRONMENT USING IRS-1C
SATELLITE DATAVIRENDRA PATHAK1 AND ONKAR DIKSHIT2
1. Department of Civil Engg., I.E.T. , Sitapur Road, Lucknow, U.P., India
2. Department of Civil Engg., I.I.T. Kanpur, Kanpur, U.P., India
vireniet@hotmail.com
ABSTRACTThe paper presents investigations to determine the suitability of
conventional per-pixel approach and results of per-field (segment)
classification for classifying Indian urban environment using high spatial
resolution satellite data. Three different types of classifications were
performed: the per-pixel classification, per-field GML classification and the
per-field neural classification. Result showed that per-field classification
improves overall classification accuracy up to 25% in comparison to perpixel approach.
1.0 INTRODUCTION
The past five decades have seen a phenomenal increase in thegrowth of urban population in India. All this rapid and haphazard growth ofurban sprawl and increasing population pressure is resulting in deteriorationof infrastructure facilities, loss of productive agricultural lands and green
open spaces besides causing air pollution, health hazards and micro-climaticchanges. To address these issues effectively, one requires up-to-date andaccurate data at regular intervals of time on the changing urban sprawl,
urban land use, urban resources and urban environment. It is here thatsatellite remote sensing with its ability to provide reliable and accurate data
may offers excellent possibilities to map, monitor and measure the various
facets of urban development.
Conventionally, land use maps derived using remote sensing data
have been prepared using coarse resolution satellite data with per-pixel
spectral (PPS) classifiers like minimum-distance-to-means and Gaussian
maximum likelihood (GML) classification methods (Mather, 1985).
However, the levels of details that could be delineated were very limited.
Later on the same techniques and features were used for classification withhigh-resolution satellite images of urban areas from SPOT HRV andLandsat TM sensors (Toll and Kennard, 1984). Unfortunately, the results
were not encouraging. The main reasons for this apparent lack of successwere that the conventional classification techniques and features were notsufficient for urban land use classification. Therefore, with the availabilityof high-resolution data some new alternative approaches need to be
explored for information extraction.

111
405

October 2004, Agra, India

Some of the new approaches which could be used for this purpose arebased on artificial neural network, fuzzy approach, inclusion of spatial
information in the classification process etc. Spatial information could be
included in the form of texture or per-field basis. Inclusion of spatial
information in the form of texture using the window-based approach has
inherent drawback of choosing a suitable window size. The per-field orregion base is important because a region as a whole contains more
information than its individual pixels, but also because regions are atomic
entities for structural and semantic analysis in middle and high level vision.
This study presents investigation pertaining to the region-based approach ofclassification for a typical urban environment.
2.0 OBJECTIVE, STUDY SITE AND DATA RESOURCES
The experiments reported in this work were mainly implemented toachieve the following main objectives:To investigate suitability of per-pixel spectral classifier for highresolution data of urban environment.
To investigate per-field method of incorporating spatial
information in the classification process.
To asses utility of the proposed per-field approach forclassification of high spatial resolution satellite data.

The study has been carried for Lucknow city, the state capital ofnorthern Indian state of Uttar Pradesh. It is situated in the upper Gangetic
plains of the country, the geographical extent of study area lies within North
latitudes 26 45 to 27 and the East longitudes 8050 to 815 . From thestudy of available maps, field visits and previous knowledge about thesestudy sites, it was observed that for Lucknow study site 12 classes covered
the majority of urban land use features (Table 1).

The satellite data products used for the study was procured from linear
image self scanning (LISS)-III sensors on board IRS-1C satellite throughNational Remote Sensing Agency (NRSA), Hyderabad, India (Table 2). A
central extract of 512 x 512 pixels covering major portion of urban areas
was extracted from the satellite image for the study. In addition to thesesatellite data products corresponding topographic and land use maps werealso used.
3.0 EXPERIMENTAL METHODOLGY

In the first part, per-pixel spectral classifications were carried out
using GML approach with pure spectral features to asses its suitability for
Indian urban environment. It was also intended for making comparison withthe results obtained using other approaches. Initially, classification was
carried out using 3 bands (B2, B3, B4) and then short wave Infra red band
(SWIR) was added to see its effect on classification. The training and test

112

New Technologies for Urban Safety of Mega Cities in Asia
406

ICUS Report 6pixels for different classes were selected with the help of various maps
available for the city, field visits, and by employing the experience of theauthors about various classes in the city. Sample size for training and test
were calculated at a confidence level of 99% and a desired precision of 
5% using equation suggested by Toratora (1976).
Table 1: Classes in the study area and their brief description
S. no.
1
2
3
4
5
6
7
8
9
10
11
12

Name
Agriculture-1
Agriculture-2
Commercial
Educational institutes
Government establishment
Grassy landHigh residential
Medium residential
Park
Reserve forest
River
Water body

Description
Agriculture area having crops at middle stage of growth
Agriculture area having crops at early stage of growthCentral business area of the city
Various educational Institutions
Different Government establishments
Big patches of lands having grass only
Residential areas with more than 600 persons/hectare
Residential areas with 400 to 600 persons/hectare
Parks for recreational activities
A big portion of land reserved for forest
River Gomati flowing from left to right
Various small water bodies in the study area

Table 2 Satellite data characteristics for study areas
SensorBands

Resolution
(m)
B2
23.5
B3
23.5
LISS III
B4
23.5
B5
70.5*
PAN
5.8
* resampled to 23.5 m.

Size(pixels)
512 x 512
512 x 512
512 x 512
512 x 512
2048 x 2048

Wavelength( m)0.52-0.59
0.62-0.68
0.77-0.86
1.55-1.70
0.50-0.75

SpectralRegion
Green
Red
NIR
SWIR
Panchromatic

Path/Row

100/52

Experimental methodology for per-field based classification is divided
into four stages i.e. Determination of threshold, segmentation of imagery,refinement of segmented imagery followed by classification based on perfield approach (Figure 1). For finding threshold for a given spectral band, anapproach modified after Nagao and Matsuyama (1980) was implemented.
The investigations used three different thresholding methods, namely Otsu
(1979), Trussel (1979) and Kapur et al. (1980). These algorithms wereapplied using a sliding window approach with 5x5 window size.
Using thresholds obtained by using the aforementioned approach, thespectral bands were subjected to segmentation. There are two types ofimage segmentation that are based on detection of boundary or growth ofregion (Nevatia, 1982; Choo et al., 1990).
A region-based approach was preferred because finding precise edges insuch images is extremely difficult. The approach calculates a merge-score.
A merge-score less than one indicates a preference for merging, whilevalues greater than one dictates against merging. It is possible to incorporate
many segment attributes to determine the merger of segments. The

Per-field Classification of Indian Urban Environment using IRS-1C Satellite Data
407

113

October 2004, Agra, Indiasegmentation algorithm operates in two phases. In the first phase, initial
segments were grown from randomly selected seed pixels. After that thesecond phase started from the first pixel in the image by scanning from left
to right and top to bottom. The second phase considered all those pixels thatwere not included in segments grown during the first phase.
Spectral features

Determination of best global thresholdfor every band

Segmentation of image using region growing
approach with global theshold values

Refinement of segmented image using grandmerge score criteria

Segment-based classification

Accuracy assement

Figure 1: Overall methodology for per-field classifications
The output of this process was a label image with a label number
assigned to each segment. The label image obtained as a result of the initial
segmentation was refined iteratively using region-merging approach
proposed by Beveridge et al. (1989). After getting refined label image,various properties of segments like, minimum, maximum, mean, median,standard deviation, covariance, kurtosis and skewness values were
calculated from spectral values of segments. Apart from these measures,

114

New Technologies for Urban Safety of Mega Cities in Asia
408

ICUS Report 6

texture measures Mean, Con and Entropy (Haralick et al., 1973) were also
calculated.
In the final stage, these segments were classified using various
spectral and textural properties of segments. Textural properties likestandard deviation (SD), GLCM texture feature Mean were used. Threedifferent types of classifications were performed, the per-pixel GMLC, perfield GMLC and per-field classification. For neural classification, Resilient
Backpropagation method was used. The accuracy analysis was carried out
using two approaches. The first measure of classification accuracy is basedon the number of correctly classified segments. The other measure is basedon -coefficient calculated using number of pixels corresponding tocorrectly classified segments. Pair-wise statistical tests were performed toassess the significance of any differences observed between twoclassifications using a Z statistic (Congalton and Green, 1999).
For testing the proposed per-field based classification approach onhigh resolution data, a simulated high spatial resolution data set of study site
was generated by image fusion using wavelet based substitute principal
component analysis (SPCA) approach (Li et al., 1999). High spatial
resolution PAN and low resolution LISS-III data were used for generating
simulated high spatial resolution data set. Experiments were carried out
using per-field based classification approach out in similar manner as it wasdone for normal data set.
4.0 RESULTS AND ANALYSISThis section presents results of various experiments carried out toachieve various objectives and to study importance of spatial properties in
the classification of urban environment.
4.1 Classification using spectral features
Classification results are presented in the Table 3. Classification
accuracy for grassy land, reserve forest, river and water body was
acceptable but for rest of the classes accuracy was poor. For classes
commercial, educational institutes and government establishment  coefficient was lesser than 0.50. The overall accuracy was also very low.
This low accuracy may be due to the fact that most of the classes werehighly heterogeneous, there were many classes with low seperability values
and few classes had similar biophysical environment.
Analysis of results suggests that classification results are less than
acceptable due to high heterogeneity and non-normal behaviour of most of
the classes. These poor classification results also suggest that spectralfeatures alone are not sufficient for urban land use classification having highheterogeneity and non-normal behaviour and some additional information
like spatial information in the form of texture, size, shape may be required.

Per-field Classification of Indian Urban Environment using IRS-1C Satellite Data
409

115

October 2004, Agra, India
Table 3 also presents result of GML classification after including
SWIR band with three spectral bands B2, B3 and B4. It was observed thatwith the inclusion of SWIR band, there was improvement in classification
accuracy for most of the classes. Though, this increase in classification
accuracy was statistically significant only for one class (commercial) but
due to increase in accuracy of all other classes, overall accuracy improved ina statistically significant manner. This shows that, although SWIR band haspoor spatial resolution but its spectral properties help in improving
classification accuracy when separation amongst classes is poor and theclasses are highly heterogeneous.
Table 3 Classification accuracy with spectral bands
S. no.
1
2
3
4
5
6
7
8
9
10
11
12
a
b
zba

Class name

Agriculture-1
Agriculture-2
Commercial
Educational institutes
Government establishment
Grassy landHigh residential
Medium residential
Park
Reserve forest
River
Water body
Overall
3 bands
3 bands + SWIR
Z-statistic between b and aTrainingab0.65 0.75
0.61 0.82
0.42 0.57
0.44 0.51
0.15 0.19
0.87 0.92
0.80 0.85
0.81 0.91
0.68 0.68
0.94 0.93
0.95 0.95
0.84 0.87
0.68 0.74

zba
1.33
3.16
1.90
0.91
0.69
1.02
0.83
1.90
0.02
-0.31
0.00
0.44
3.19

Test
a
0.74
0.73
0.45
0.49
0.05
0.87
0.75
0.74
0.69
0.91
0.92
0.92
0.68

b
0.78
0.77
0.71
0.53
0.11
0.89
0.81
0.85
0.73
0.90
0.92
0.93
0.74

zba
0.71
0.58
3.54
0.49
1.49
0.49
0.81
1.77
0.53
-0.26
0.00
0.29
2.81

4.2 Classification using per-field approach
Threshold values were determined for all bands considered for the
study. It was observed that results of Otsu and Kapur et al. methods weresimilar while threshold values from Trussel were slightly higher than othertwo methods. Threshold values obtained using Otsu method were chosen to
carry out further analysis. After selecting suitable threshold values for all
four bands, multispectral segmentation of bands was carried out. It wasobserved from segmented image that inclusion of band B5 in thesegmentation process produced poor segmentation. This could be due tovery small thresholds values obtained for band B5. Segmentation carried out
using three bands (B2, B3 and B4), produced good segmented image.
Therefore, further analysis was carried out using only these three bands.
Table 4 shows the results of per-field based classifications. It wasobserved from the results that accuracy in terms of number of correctlyclassified segments was lower than the number of correctly classified pixels.
The reason for this becomes obvious when we see test accuracy of classes

116

New Technologies for Urban Safety of Mega Cities in Asia
410

ICUS Report 6like commercial and educational institutes. In case of commercial class,
only two out of eight segments have been correctly classified whereas interms of number of pixels, more than 97% of the pixels have been correctlyclassified. Similarly for class educational institutes only one out of eightsegments have been correctly classified whereas in terms of number ofpixels, more than 90% of the pixels have been correctly classified for thisclass.
Table 4: Results of per-field based classification
S. no.

Class name

In terms of segment
a
b
c
10
8
80.00
8
7
87.50
8
2
25.00
8
1
12.50
7
4
57.14
4
2
50.00
1
1
100.00
2
1
50.00
5
2
40.00
4
3
75.00
4
4
100.00
8
7
87.50
69
42
60.87

1
2
3
4
5
6
7
8
9
10
11
12
a
b
c
d
e
f
g

Agriculture-1
Agriculture-2
Commercial
Educational institutes
Government establishment
Grassy landHigh residential
Medium residential
Park
Reserve forest
River
Water body
Overall
Number of segments for training / test
Number of correctly classified segments% of correctly classified segments
Number of pixels corresponding to training / test segments
Number of correctly classified pixels% of correctly classified pixels
 -coefficient

Test accuracy
In terms of pixels
d
e
f
229
180
78.60
2623
1983
75.60
2754
2691
97.71
4943
4482
90.67
3477
3148
90.54
7768
7740
99.64
15558 15558 100.00
15412 15407
99.97
1171
1125
96.07
9954
7329
73.63
2297
2297 100.00
291
286
98.28
66477 62226
93.61

Table 5 shows a comparison between classification results using perfield based GML and per-pixel GML classification approach. It wasobserved that except reserve forest, classification accuracy for most of theclasses was statistically significantly higher using per-field based approach.
The overall test accuracy in terms of  -coefficient increased from 0.68 to
0.92 (increase of 24%). The classified image using per-field based approach
looks more like a thematic map in comparison to per-pixel classified image.
For three fused bands obtained using wavelet based SPCA approach,threshold values were obtained from Otsu method. Segmentation of fusedbands was carried out and subsequently merging was done for refinement ofinitially segmented image. Total of 550 iteration of segment merging
algorithm were required before merging stopped. Corresponding to refinedsegmented image, per-pixel and per-field based GML classifications werecarried out for simulated data set. The same approach of classification was
adopted, which was used with the multispectral data set. Table 6 presents acomparison of per-field and per-pixel classification results. The overall test
accuracy in terms of  -coefficient increased from 0.70 to 0.95 (increase of25%).

Per-field Classification of Indian Urban Environment using IRS-1C Satellite Data
411

117

g
0.79
0.75
0.98
0.90
0.90
1.00
1.00
1.00
0.96
0.70
1.00
0.98
0.92

October 2004, Agra, India
Table 5: Comparison of per-pixel and per-field based classification
accuracy ()S. no.

Class Name

1
2
3
4
5
6
7
8
9
10
11
12
a
b
zba

Agriculture-1
Agriculture-2
Commercial
Educational institutes
Government establishment
Grassy landHigh residential
Medium residential
Park
Reserve forest
River
Water body
Overallper-pixel GML
per-field based GML
Z-statistic between b and a

a
0.65
0.61
0.42
0.44
0.15
0.87
0.80
0.81
0.68
0.94
0.95
0.84
0.68

Trainingbzba
0.61 -0.24
0.99 5.60
0.99 8.29
0.88 5.05
0.90 9.04
1.00 3.03
1.00 4.48
1.00 3.89
1.00 6.20
0.70 -3.26
1.00 1.24
0.98 1.35
0.93 7.26

a
0.74
0.73
0.45
0.49
0.05
0.87
0.75
0.74
0.69
0.91
0.92
0.92
0.68

Test
b
zba
0.79
0.29
0.75
0.15
0.98
6.87
0.90
4.67
0.90 11.17
1.00
2.78
1.00
5.17
1.00
5.13
0.96
2.87
0.70 -2.78
1.00
2.77
0.98
0.73
0.92
6.60

Table 6: Comparison of accuracy () between per-pixel and per-field basedclassification with fused image
S. no.
1
2
3
4
5
6
7
8
9
10
11
12
a
b
zba

Class name

Agriculture-1
Agriculture-2
Commercial
Educational institutes
Government establishment
Grassy landHigh residential
Medium residential
Park
Reserve forest
River
Water body
OverallPer-pixel classification
Per-field classification
Z-statistic between b and a

a
0.79
0.90
0.48
0.47
0.28
0.84
0.77
0.65
0.63
0.83
0.65
0.70
0.71

Training
b
zba
0.78
-0.46
1.00
35.30
0.95 196.19
0.95 126.16
0.36
18.44
0.99 101.36
1.00 201.69
1.00 213.30
0.87
45.45
1.00 165.30
1.00 147.36
0.82
16.66
0.96 388.40

a
0.57
0.66
0.49
0.46
0.28
0.85
0.77
0.64
0.62
0.83
0.65
0.69
0.70

Test
b
zba
0.70
9.18
0.89
50.50
0.95 195.73
0.93 125.45
0.36
18.35
1.00 108.40
1.00 201.25
0.98 213.69
0.82
36.38
1.00 165.75
1.00 147.28
0.82
16.62
0.95 390.24

These results reveal that invariably for all the classes, accuracy
increased in a statistically significant manner in case of per-field basedclassification approach. This clearly indicates that use of the proposedclassification method would be appropriate even for high resolution data.

118

New Technologies for Urban Safety of Mega Cities in Asia
412

ICUS Report 6


5.0 CONCLUSIONSThis paper has demonstrated the significance of spatial properties in
the classification of urban environment using IRS-1C satellite data. This
paper has also demonstrated that proposed approach of per-field (segment)
based classification is suitable for classification of urban environment evenwith high resolution spatial data. The classification results with thisapproach showed significant improvement over per-pixel approach. The
following conclusions can be drawn from the analysis carried out in thisstudy:








The poor classification results with pure spectral features suggestthat spectral features alone are not sufficient for urban land use
classification having high heterogeneity and non-normal behaviour.
Therefore, some additional information like spatial information in
the form of texture, size, shape may be required.
Inclusion of SWIR band in the classification process with IRS-1C
data helps in improving classification results for classes having
high heterogeneity.
Per-field based classification provides statistically significantly
higher accuracy (up to 25%) than per-pixel approach.
The per-field ANN classification provides slightly higher, thoughstatistically insignificantly different, test accuracy than the perfield GML classification.
Classified image obtained as a result of per-field basedclassifications looks more like a thematic map while making acomparison with results of per-pixel approach.
Per-field based classification of fused data set obtained from highspatial resolution PAN and low spatial resolution LISS-III,provides significantly higher accuracy. This clearly indicates thatper field approach would be appropriate for classification of urban
environments from high spatial resolution satellite images.

REFERENCES
Beveridge, J. R., Griffith, J., Kohler, R. R., Hanson, A. R., and Riseman, E.
M.,1989. Segmenting Images using localised histograms and region
merging. International Journal of Computer Vision, 2, 311-347.
Choo, A. P., A.J. Maeder and B. Pham, 1990. Image Segmentation forcomplex natural Scenes,. Image and Vision Computing, vol. 8, pp. 155163.
Congalton, R. G. and Green, K., 1999. Assessing the Accuracy of RemotelySensed Data: Principles and Practices. CRC Press, Inc.,U.S.A.
Haralick, R. M., Shanmugam, K., and Dinstein, I., 1973. Textural features
for image classification. IEEE Trans. on Systems, Man, and Cybernetics.
SMC-3, 610-621.
Kapur, J. N., Sahoo, P. K. and Wong, A. K. C., 1985. A new method forgrey-level picture thresholding using the entropy of the histogram.
Computer Vision and Image Processing, 29, 273-285.

Per-field Classification of Indian Urban Environment using IRS-1C Satellite Data
413

119

October 2004, Agra, IndiaLi., J., Zoju, Y., and Li, D., 1999. PCA and wavelet transform for fusing
panchromatic and multispectral images. SPIE’s International
symposium on Aero Scene: Image Exploitation and Target
Reconstruction; Orlando, Florida, U.S.A, 3719, 5-9.
Mather, P.M., 1985. A computationally efficient maximum likelihoodclassifier employing prior probabilities for remotely sensed data.
International Journal of Remote Sensing. 6 (2), 369-376.
Nagao, M. and Matsuyama, T., 1980. A structural analysis of complex
aerial photographs. Plenum, New York.
Nevatia, R., 1982. Machine Perception. Printice-Hall, Englewood Cliffs,
NJ.
Otsu, N., 1979. A threshold selection method from grey-level histograms.
IEEE Trans. on systems, Man, and Cybernetics, SMC-9, 62-66.
Toll, D. L. and Kennard, R. E., 1984. Investigation of SPOT spectral andspatial characteristics for discriminating land use and land cover in
Prince George’s county, Maryland. In SPOT simulation Applications
Handbook, Falls Church: American Society for Photogrammetry, 165170.
Tortora, R., 1978. A note on sample size estimation for multinomial
populations. The American Statistician, 32 (3) 100-102.
Trussel, H. J., 1979. Comments on ‘Picture thresholding using an iterative
selection method’. IEEE Trans. on Systems, Man, and Cybernetics,
SMC-9 (5), 311.

120

New Technologies for Urban Safety of Mega Cities in Asia
414

SURFACE CLIMATIC IMPACTS OF
URBANIZATION IN THE HOCHIMINH CITY,
VIETNAM: AN INTEGRATED STUDY WITHREMOTE SENSING AND MODELING
TRAN HUNG1 AND YOSHIFUMI YASUOKA2
Institute of Meteorology and Hydrology, Hanoi, Vietnam
2
Institute of Industrial Science, University of Tokyo, Tokyo, Japan
tranhung@iis.u-tokyo.ac.jp
1

ABSTRACT
Hochiminh City, the biggest industrial, commercial center in Vietnam
with population of more than 5 millions people, has experiencing rapid
urban expansion during the last decade. A large amount of forest andagricultural land has been converted into housing, infrastructure andindustrial estates. The resultant impervious urban surface alters the surface
energy balance and surface runoff, which in turn could pose serious
environmental problems for its inhabitants (e.g., urban waterlogged andthermal pollution). In this paper, we utilize satellite images (TM and
ASTER) to derive surface biophysical parameters such as fractional
vegetation cover (Fr), surface radiant temperature (Ts), surface moistureavailability (M0) and evapotranspiration fraction (ET/Rn) are derived for
different years during 1989 – 2002 period. The changes over the years of
surface biophysical parameters are, then, examined in association withland-use changes to illustrate how these parameters respond to rapid urban
expansion in Hochiminh City and surrounding region. This study attempts
to provide environmental awareness to urban planners in future urban
development.
1.0 BACKGROUND
Hochiminh City, one of fast-expanding Asian Metropolis
agglomerations with population of more than 5 millions, is the biggest
industrial, commercial center in Vietnam. The population density in theurban area is reported as of 9,373 persons per square kilometers on April 01,
1999. High economic growth and increased employment opportunities caused
substantial influx of labor immigration. The urban population has increased
1.5 times from 1977 to 1999 mainly due to immigration. Currently, thenatural growth is 1.36% while the immigration growth is 0.77% annually.
As the city expands, prime agricultural land and habitats such as forests andwater basins are transformed into land for housing, roads, and industry. This
has added more pressure on the land use demand and the drastic changes ofland cover and land-use caused by urbanization could significantly affectsocial, economic and ecological conditions in a large urban footprint area.
While effective urban land use planning can help guide urban development
away from vulnerable ecosystems, it appears impossible without deep

151
415

October 2004, Agra, India

understanding of processes governing the change dynamics and their interrelations in urban and sub-urban areas.
It is well recognized that the multi-spectral, multi-temporal satellite
imageries provide the most reliable, up-to-date and consistent means ofmonitoring land cover changes associated with urbanization at the regional
scale. The land cover information, properly classified, can provide aspatially and temporally explicit view of societal and environmental
attributes and can be an important complement to in-situ measurements. In
addition, Owen et al. (1998) noted that quantitative biophysical information
could also be extracted from existing satellite data, thus adding a great
potential for practical application to regional planning and urban ecology.
Remotely sensed surface radiant temperatures were successfully used in thestudies of the so-called urban heat islands, while various vegetation indexes
have long been used in urban vegetation studies. Gillies et al. (1997) has
described the characteristic triangular-shaped envelope of pixels as viewed
on a scatterplot of vegetation cover and surface radiant temperature forsatellite remotely sensed pixels. On the other hand, Soil-VegetationAtmosphere Transfer (SVAT) model can be used to predict changes invarious meteorological variables, including substrate temperature,atmospheric temperature and surface moisture as a function of time. The
remotely-sensed measured variables in terms of surface radiant temperature(Ts) and NDVI (after normalizing to minimize the effects of surface andatmospheric variability) could be then fitted to the model’s simulated onesin order to solve the inverse problem of estimating fractional vegetation
cover, surface moisture availability and evapotranspiration fraction (Gillies
et al., 1997).
In this paper, we attempt to utilize satellite imageries in association
with existing ancillary data to monitor and analyze land-use dynamics in
Hochiminh City and surrounding region during 16 years (1986-2002).
Based on revealed urban development patterns, major land-conversion
zones are delineated. We then have applied the “triangle method” to derive
surface biophysical parameters such as surface moisture availability (M0),evapotranspiration (ET/Rn) fraction and vegetation fraction (Fr) over theyears from high-resolution TM, ETM+ and ASTER images. The main
objective of this paper is to illustrate the expanded capability of remotesensing in studying the impacts of rapid urbanization on regional
environment by analyzing the changes in the derived biophysical parameters
associated with urban development in the Hochiminh City region between
1989 and 2002.
2.0 URBAN DEVELOPMENT PATTERNS BY REMOTE SENSING
The study area is located between 106020’01’’ – 106059’48’’
Longitude and 10040’49’’ – 11009’51’’ Latitude. Administratively, it
composes of major part of Ho Chi Minh City and parts of surrounding Long
An, Tay Ninh, Binh Duong and Dong Nai provinces, which is reported tohave rapid built-up expansion since the last decade (Fig. 1). To provide
temporal land cover and land use information, various satellite images such

152

New Technologies for Urban Safety of Mega Cities in Asia
416

ICUS Report 6

as MSS (1986), TM (1989, 1993), ETM+ (1999, 2001, 2002) and ASTER(2001) are obtained for the study area. Satellite images are corrected foratmospheric attenuation and geo-referenced to a common 1:50,000 UTM
topographic map and re-sampled to 30m resolution. The image analysis isdone on single-date images individually including ML classification andknowledge-based post-classification techniques incorporating texture,
vegetation information and ancillary existing land-use maps of 1997. Withbiophysical characteristics of the land cover as the major focus of the study,
the final analysis consolidates classified images into some major land-covercategories: built-up, paddy/irrigated agricultural land, plantation, forest, drybaresoil, wet baresoil, wasteland and water-body. Change detection is thenapplied based on overlaying classified images in order to understand the landuse conversion and to build time-series data for a particular land-use type
for the 1986 – 2002 period.

Figure 1: Map of the study area with some focus spots: for inner city – 1(Q. Phu Nhuan); suburban - 2 & 3 (Q. Go Vap & Thu Duc);
industrial zones – 4 (South of Binh Duong); agricultural area –5 (H. Hoc Mon)
As the result, the spatial patterns of urban development are foundchanging over the years (Fig. 2). Along with the continuing urban
densification of highly urbanized areas in the inner city districts such as
Quan 6, Phu Nhuan, the City significantly expands into northern and eastern
suburban areas during 1989 – 2002 (e.g., Q. Go Vap, Quan 8, Q. Thu Duc, Q.
2 and southern part of Binh Duong province). The rate of urban expansion isobserved of more than 7 percent per year in some neighborhoods of the Go
Vap and Thu Duc districts. Figure 3 shows trend of urbanization of some
representative districts in the inner city and suburban areas. The major to-

Surface Climatic Impacts of Urbanization in the Hochiminh City, Vietnam
417

153

October 2004, Agra, India

urban-land conversion is observed from: 1) irrigated land (paddy fields,
wetland) to built-up; 2) agricultural land (cash crops, orchards) to built-up; 3)
bush land / range land to pre-construction wasteland and industrial estatesareas; and 4) urban densification. Here, we select 5 sub-areas representing
different patterns, type and degree of urban development (1 – inner city, 2 –dry suburb, 3 – wet suburb, 4 - industrial zones & 5 – agriculture as controlzone) for more detailed analysis of the changes in surface biophysicalparameters (Fig. 1).

Figure 2: RS-derived urban expansion around HCM area during 1989 –2002 (white color shows non-urban; gray - urban area before
1989; blue, green, brown and red show new urban land by 1993,
1999, 2001 and 2002)
3.0 REMOTELY-SENSED BIOPHYSICAL PARAMETERS
3.1 Surface temperatures and NDVIThe Landsat TM raw data of 1989 and 1993, ETM+ of 1999, 2001
and 2002 and Terra ASTER data of 2001 are used to extract biophysicalsurface parameters (more details could be found in Tran & Yasuoka, 2001).
Thermal radiances at the original spatial resolution are converted to atsensor temperatures via the Planck equation and then to at-surface
temperatures based on the equations and calibrating coefficients developedby the National Aeronautics and Space Agency (NASA) and ERSDAC
respectively. Normalized Difference Vegetation Index (NDVI) is calculated
from visible red (TM Band 3 or ASTER B2) and near infrared (TM B4 or
ASTER B3) reflectance by equation: NDVI = (NIR – R) / (NIR +R).

154

New Technologies for Urban Safety of Mega Cities in Asia
418

ICUS Report 6

100

Percentage Urbanized (%)

80

60

40

20

0
1986

1988

1990

1992

1994

1996

1998

2000

Q. Go Vap

Q. Phu Nhuan

Q. Thu Duc

Q. 2

Q. 8

Q. 9

Q. 11

H. Hoc Mon

2002

Years

Figure 3: Increase in percentage of urbanized areas in selected inner andsuburban districts of Hochiminh City during 1986-2002
3.2 Universal triangle and biophysical parameters
We derive biophysical parameters from satellite images based on thetriangle method (Gillies et al., 1997). The water and cloud contaminatedpixels, which tend to be localized at negative of NDVI and lower values ofT0, are excluded from the analysis. Firstly, we normalize the calculated
NDVI and Ts, to reduce inter-scene variability in the state of the surface, thephenology of the vegetation and the condition of the atmosphere (e.g., haze,wind speed, humidity). Transformation of NDVI to a scaled NDVI (N*) is
accomplished using equation:N*

NDVI NDVI 0
NDVI s NDVI 0

where NDVI0 is limit for bare soil and NDVIs is limit for 100%vegetation cover are selected empirically for each image. Then, thefractional vegetation cover (Fr) is calculated as Fr = N*2 according toCarlson & Arthur (2000). Temperature values are also scaled between thewarmest (Tmax) and coldest (T0) surface temperatures corresponding to drybare soil and wet soil at 100% of vegetation cover. The temperature anchor
values are determined by inspection of the NDVI/Ts scatterplots (Owen etal., 1998) and observed ambient air temperature (Ta) recorded at the Tay
Ninh, Xuan Loc meteorological stations at the time of satellite overpass.
Normalization to a scaled surface temperature is done based on equation:
T*

Ts T0
.
Tmax T0

The normalized Fr/T* scatterplots are, then, constructed for the 1989,
1993, 2001 and 2002 images as the “universal triangle” as shown in Figure

Surface Climatic Impacts of Urbanization in the Hochiminh City, Vietnam
419

155

October 2004, Agra, India

4. With input parameters from observation data recorded frommeteorological stations at Tay Ninh and Xuan Loc, the SVAT (soilvegetation-atmosphere transfer) model of the Penn State University is used
to derive fractional vegetation cover (Fr), surface soil water content (M0)and evapotranspiration fraction (ET/Rn). The SVAT model output in formsof M0 and ET/Rn isopleths are overlaid on the normalized Fr/T* scatterplots
using third-order polynomial relations to compute the M0 and ET/Rn fromFr and T* for the 1989, 1993, 2001 and 2002 images in the study.

Figure 4: Universal triangle as scaled Fr/T* scatterplot for the Feb. 04,
1993 TM scene and overlaid surface moisture availability isolines(M0 = 0, 0.2, 0.4, 0.6, 0.8, 1) based on the SVAT model output.
4.0 URBANIZATION AND REGIONAL CLIMATIC PARAMETERS
With the derived biophysical parameters over the years, it isinteresting to examine the relationship between them and the urbanization
process. As TM/ETM+ pixels are of small size, T* and Fr have considerable
large variations creating difficulties in tracing out representative changes
over years, biophysical parameters are aggregated from 30x30m to
300x300m spatial resolution using average values. Examining the Fr/T*
scatterplots, there is a clear distinction between dense urbanized pixels fromother land cover types in terms of T* (> 0.6) and Fr (< 0.1), while suburban
residential areas have large variability in T* (0.3 0.6) due to variable
vegetation covers. Statistically, it is found a significant negative relationshipbetween % urbanized and Fr (r = 0.473, p < 0.001 for 2001 data) andsignificant positive correlation with Ts (r = 0.491, p < 0.0001).
The changes in T*, Fr, Mo and ET/Rn between 1993 and 2001 for 5
selected subgroups are summarized in Table 1, showing the study area ingeneral tends to become warmer and drier. Figure 5 shows the trajectories
for aggregated TM pixels representing 4 urban development classes from1993 to 2001 & 2002, which suggests urbanization is the primary cause of
the migration of the pixels in the Fr/T* scatterplot. However, the extent anddirection of the path appeared to be governed by other factors such as the
pixel’s initial location in the triangle and pixel geographical neighborhood.

156

New Technologies for Urban Safety of Mega Cities in Asia
420

ICUS Report 6

It seems that the conversion from agricultural lands, especially fromlowland irrigated areas to dense residential areas (e.g., Thu Duc, Q.2) leads
to most regional microclimate changes (e.g., significant decrease in Mo,
ET/Rn and significant increase in urban run-off).
Table 1: Comparison of mean migration of biophysical parameters from1993 to 2001 for 5 distinct groupings based on urban
development patterns

1- Inner City
(Phu Nhuan)
2- Suburban(Go Vap)
3- Suburban(Thu Duc)
4- Industrial
Zones (BinhDuong)
5- Agriculturalarea

Sample
size

Mean
T*

Mean
Fr

Mean
Mo

Mean
ET/Rn

164

+0.1438-0.0001-0.1983-0.0619218+0.2519-0.2134-0.3121-0.1032

113+0.3213-0.4673-0.5217-0.1527322+0.0942-0.1425-0.2025-0.1382525-0.0214+0.2031+0.0118-0.0025

1.0

1 - Phu Nhuan in 1993

Fractional vegetation cover

1 - Phu Nhuan in 2001
1 - Phu Nhuan in 2002

.8

2 - Go Vap in 1993
2 - Go Vap in 2001

.6

2 - Go Vap in 2002

warm and dry

Thu Duc

3- Thu Duc in 1993
3 – Thu Duc in 2001

.4

3 – Thu Duc in 2002
4 - Binh Duong in 1993

Go Vap.2

4 – Binh Duong in 2001

Binh Duong

4 – Binh Duong in 2002

moist and cool

0.0
0.0

5 – Agriculture in 1993,
2001 & 2002

Phu Nhuan

.2

.4

.6

.8

1.0

Scaled surface temperature

Figure 5: Migration of pixels (averaged for 5 focused sub-areas) on
universal triangle between 1993, 2001 and 2002

Surface Climatic Impacts of Urbanization in the Hochiminh City, Vietnam
421

157

October 2004, Agra, India

5.0 CONCLUDING REMARKS
Preliminary results from this case study in Hochiminh City
demonstrate the capability of satellite remote sensing not only in monitoring
the surface development but also in determining useful climate and land
surface parameters such as Ts, Fr, ET/Rn and Mo. Significant changes inthese surface climate variables ( T*, ET/Rn) are found to depend on the
speed of urbanization as well as the initial percentages of urban coverageand vegetation amount. Continuing works are carrying out to include moreground observations and factors such as sub-region’s urbanized structureand stage of urban developments into modeling of microclimate changes.
This study is a part of an on-going research at the Institute of Industrial
Science, University of Tokyo focusing on using remote sensing to study
urban growth in Asian cities and its impacts on regional climate. We wish to
thank Prof. Carlson T. N. at the PSU (US) and Dr. Tran Thuc at the IHM(Vietnam) for providing SVAT model & meteorological observations data
to use in this study. We also wish to acknowledge the Japan Science andTechnology Agency for the funding of this research at the IIS, University ofTokyo, Japan.
REFERENCES
Carlson T.N. & Arthur S.T., 2000. The impact of land use – land coverchanges due to urbanization on surface microclimate and hydrology: asatellite perspective. Global and Planetary Change, Vol 25, 49-65
Gillies R.R., Carlson T.N., Cui J., Kustas W.P. & Humes K.S., 1997. A
verification of the ‘triangle’ method for obtaining surface soil watercontent and energy fluxes from remote measurements of the Normalized
Difference Vegetation Index (NDVI) and surface radiant temperature.
International Journal of Remote Sensing. Vol 18(15), 3145-3165
Owen T.W., Carlson T.N. & Gillies R.R., 1998. An assessment of satellite
remotely sensed land cover parameters in quantitatively describing theclimatic effect of urbanization. International Journal of Remote Sensing.
Vol 19(9), 1663-1681
Tran H., Yasuoka Y., 2001. Remote Sensing to Assess Regional Climatic
Effects of Urban Expansion in Northern Bangkok, Thailand.
Proceedings of the Int’l Conference on Computer in Urban Planning and
Urban Management. University of Hawaii at Manoa, USA.

158

New Technologies for Urban Safety of Mega Cities in Asia
422

SUBSURFACE GEOTECHNICAL
CHARACTERIZATION MAP OFBANGALORE CITY USING 3-D ANALYSTIN GIS
T.G. SITHARAM1, C.S. VISWANATHA2, M.S. SUDARSHAN2 AND
P.S.R. NARASIMHA RAJU2
1
Indian Institute Of Science, Bangalore, India
2
Torsteel Research Foundation in India, Bangalore, India
mssudarshan60@yahoo.co.in
ABSTRACTThe geotechnical characterization of the subsurface in a city leads tounderstanding the ground conditions, area wise, and to obtain details of soil
stratification and soil characteristics. This helps in proper planning in
positioning important structures and conceiving suitable foundation systems.
Further, the regions of liquefaction and areas of magnification effects in the
ground due to earthquakes can be mapped. The paper describes thedevelopment of a detailed map (on a scale of 1:20000), containing 852
borehole data upto a maximum depth of 40 m (rock depth), generated in 3dimension for Bangalore region based on Geographic Information System(GIS) model using 3-D Analyst Package. GIS model helps in data
management, visualization, spatial analysis and decision support. The
project aims at creation of database on the existing information about
subsurface geotechnical information upto refusal or hard strata for
Bangalore region. GIS model consists of soil stratification with theirgeotechnical properties along the depth at all the borehole locations. The
final objective of this work is to develop seismic microzonation maps andliquefaction zonation maps based on the geotechnical properties in theregion.
1.0 INTRODUCTION
This project was aimed at mapping geotechnical data by developing a
GIS based subsurface model. This project was taken with a visionary idea,
to collate the enormous isolated geotechnical data that was available withvarious sources and frame in one single GIS model that could be used bywhole range of geotechnical fraternity.
The GIS based model helps in data management, to develop
geostatistical functions, 3D visualization of subsurface with geo-processing
capability and future scope for web based subsurface mapping tool.
This is envisaged not only in economizing geotechnical investigations
and avoid duplication of boreholes but would also provide geotechnicalengineers with various 3-dimensional views of soil strata and theirproperties necessary for consultancy and general prediction of soil behavior.
159
423

October 2004, Agra, India

The project is further intended for geotechnical site response andcharacterization studies for development of microzonation maps.
The work involved three major tasks as described below.
Develop a digitized map of Bangalore city with several layers of
information.
Development of GIS database for collating and synthesizing
geotechnical data available with different sources and,Develop 3 dimensional view of soil stratum presenting various
geotechnicalparameters with depth in appropriate format.

2.0 MAP AND 3-D SUBSURFACE MODELINGGIS has been used in geosciences for data collection, organization anddistribution of geological data and maps. The project in geosciences will
have many types of data sources in which GIS is an invaluable tool for
integration of many different types. Visualization is another GIS activity
which is very useful in this project. This includes creating maps on screen,producing hard copy maps and delivering maps. Arc GIS 8.3 has been usedhere with 3D analyst extension.
2.1 Digitization of map
The Bangalore map forms the base layer for development of GIS
model. The map entities were developed in view of two aspects, firstly forlocating the bore logs to the utmost accuracy on a scale of 1:20000 andsecondly for identification of bore logs by end user. With this scope of work
the map was developed with several layers of information. Some of theimportant layers considered are the boundaries (Outer and Administrative),
Contours, Highways, Major roads, Minor roads, Streets, Rail roads, Water
bodies, Drains, Landmarks and Bore locations. Digitized map wasdeveloped mainly using hard copy of Bangalore guide map, published by
Survey of India in 1983 and several other maps from standard publishers
were used for reference. Digitization of the map layers was done in
AutoCAD and then imported to Arc view GIS 8.1. Few combinations oflayers that can be viewed in the map for various information are shown in
Figures 1 & 2 below. Figure 1 depicts the location of boreholes with respect
to water features like tanks, lakes and drains within the corporate boundaryof Bangalore along with outer boundary circumscribing the ring road. It
gives a clear view of the spatial distribution of boreholes in Bangaloreregion. Also this would be helpful in prediction of soil behavior andinformation can be derived for ground water management and planning.
Figure 2 shows the location of boreholes with the elevation contours at 10m
intervals. This would give information on availability of reliable
geotechnical data on sloping terrains or valleys and could be used for land
use planning or other planning purposes. Several other layers of information
are available on the map like road (Highways, streets etc) and rail network,
bridges, culverts, Landmarks and monumental structures etc, which wouldcater to the interest of many other engineering groups. Also the isometric160

New Technologies for Urban Safety of Mega Cities in Asia
424

ICUS Report 6

view of all boreholes can be viewed by overlapping of layers to get a 3-D
projection. The 3-D modeling of boreholes is described in the section 2.3.
This view gives a visual idea of the depth to which geotechnical data isavailable in each borehole.

NE
NW
Vidhana Soudha
Lat-Long:(77o 35.46' ; 12° 58.67')

Corporate
Boundary

Outer
Boundary

SW

Drains

Water
BodiesSE

Borehole
Location

Figure1: GIS model of borehole locations with respect to water features

Subsurface Geotechnical Characterization Map of Bangalore City 3-D Analyst in GIS
425

161

October 2004, Agra, India

Figure 2: GIS model of borehole locations with respect to contours
2.2 Collation of geotechnical data
Geotechnical data was basically collated from archives of Torsteel
Research Foundation in India (TRFI) and Indian Institute of Science (IISc)
for geotechnical investigations carried out for several major projects in
Bangalore. The data collected is of very high quality carried out by seniorgeotechnical engineers for important projects in Bangalore during the years
1990-2003. So far 850 bore-log information has been keyed into the
database. Most of the data so far selected for the database is on average to adepth of 20m below the ground level with an interval of 0.5m. Another ofabout 600 borehole information is still available at different locations up todifferent depths (about 6-30m), which were carried out in connection with
geotechnical investigations all over Bangalore. The bar chart shown infigure 3 clearly gives the distribution of the boreholes classified on the depthof bore below ground level. Majority of the bores with depths greater than
15m were carried out for several grade separator projects. Most
investigations for residential and commercial complexes were below 15m.
But wherever bed rock has been encountered investigation has been
terminated at that depth. The properties keyed into the database at aparticular depth are location details, physical properties, grain size
distribution, Atterberg limits, and strength properties for soil and rock.
These boreholes spatially cover most parts of the Bangalore city and more
densely in the areas of high land use as shown in figures 1&2. Distributionof boreholes in four quadrants of Bangalore city considering Vidhana

162

New Technologies for Urban Safety of Mega Cities in Asia
426

ICUS Report 6

Soudha (shown in fig 1.) as the centre point is shown in figure 4. There isgreater scope for geostatistical analysis of the collated data to study thesubsurface features and their variation. One can use geostatistical analyst
extension of Arc GIS to deal with the common situations of limited data
availability in subsurface sampling and more effective decision making forsite characterization.

471

500
450
400
Number of bores

350
300
250
200

182

150

93

69

100

35

50
0
<6

6-15

15-20

20-30

>30

Bore depth in meters

Figure 3: Distribution of bores based on depth

NE; 163;
19%

SE; 290;35%

SW; 224;
26%

NW; 173;20%

Figure 4: Distribution of bores in quadrants for bangalore city

Subsurface Geotechnical Characterization Map of Bangalore City 3-D Analyst in GIS
427

163

October 2004, Agra, India

Single layer ofbore representing
0.5m depth

10 M
0.5 m

Figure 5: A typical borehole in 3 D
2.3 Subsurface 3-D model
The GIS model developed currently consists of 850 borehole
locations marked on the digitized Bangalore map of 1:20000 scales. The
boreholes are represented as 3 dimensional objects projecting below the map
layer in 0.5m intervals. Also image files of bore logs and properties tablehas been attached to location in plan. These 3-D boreholes are generated
with several layers with a bore location in each layer overlapping one below
the other and each layer representing 0.5 m interval of the subsurface.
Figure 5 shows a typical borehole viewed in isometric view. It consists ofseveral donut elements in different layers placed coinciding one below theother. A single donut as shown on the right in figure 5 represents 0.5 m
depth of ground in the model. Topmost donut represents the 0.5m depth of
surface strata and thereon each donut cumulates to 0.5m below ground level.
Each borehole in this model is attached with geotechnical data along
the depth. The data consists of visual soil classification, standard penetration
test results, ground water level, time during which test has been carried out,
other physical and engineering properties of soil. The model provides two
options to view the data at each borehole in order to cater for various groupsof geotechnical fraternity. In 2-D, by clicking on a borehole will display thestandard bore log information as shown in figure 6 and the respective
properties table consisting of index properties & shear strength parameters.
Apart from this each donut of any borehole is attached with soil/rockproperties at that particular depth. As such when this model is viewed in 3D
geotechnical information on any borehole at any depth can be obtained byclicking at that level (donut).

164

New Technologies for Urban Safety of Mega Cities in Asia
428

ICUS Report 6

3.0 SUMMARY AND CONCLUDING REMARKS
Digitized map of Bangalore on a scale of 1:20000 with about 12
layers of information has been prepared and presented. Geotechnical datafor 850 boreholes up to a depth of about 40m has been collated and attachedto the locations in the map using ARC View GIS 8.1 with 3D analyst
package. Further work is under progress in locating additional borehole data,
which is available for greater Bangalore region (Map development &extension work is also under progress). Once the database is fairly complete,attempts will be made to develop models of regions by contouring ofvarious properties at various depths along with the data exploration, fitting asemivariogram model, performing diagnostics to find how well the model
predicts the unknown values and comparing several models to find better
predictions of the unknown.

Figure 6: A typical display of bore log sheet

Subsurface Geotechnical Characterization Map of Bangalore City 3-D Analyst in GIS
429

165

October 2004, Agra, India

ACKNOWLEDGEMENTS
Authors thank Seismology division, Department of Science andTechnology, Government of India for funding the project titled“Geotechnical and site characterization of greater Bangalore region” (Ref no.
DST/23(315)/SU/2002 dated October 2003). Thanks to Mr. G.U Mahesh
and K.Shamanth, Project Associate who were very help full in preparationof the paper.
REFERENCES
ARC View GIS 8.1, Manuals and Handouts.
Torsteel Research Foundation in India, Geotechnical Investigation Reports(1988-2003).
Indian Institute of Science, Geotechnical Investigation Reports.
Survey of India, Bangalore guide map, 1983.
Eicher Good Earth, Bangalore map, 2002.
ESRI publishing, Subsurface Modeling with GIS.

166

New Technologies for Urban Safety of Mega Cities in Asia
430

REGISTRATION OF LASER SCANNER
POINT CLOUDS FOR A LARGE ANDCOMPLEX BUILDINGEKTA AMAR AND BHARAT LOHANI
Indian Institute of Technology Kanpur, Kanpur, India
blohani@iitk.ac.in
ABSTRACT
Terrestrial Laser scanners (TLS) can measure 3-D co-ordinates oflarge number of points in a short span of time. Scanning a large building
requires scanning from more than one position. Thus, registration of point
clouds acquired from different positions is important and essential for
preparing a complete 3D model of a building. This paper deals with theregistration of the different point cloud scans considering the common
overlapping areas in between successive scans. The detail procedure isdiscussed and also the problem faced while registering is outlined.
1.0 INTRODUCTION
The new technique of laser scanning for obtaining 3D information of
any object has revolutionized the surveying world. This technique ispopularly known as terrestrial laser scanning (TLS). Not withstanding its
recent emergence, the TLS is becoming an industry standard technique for
3D data capture. The main advantage of this technique is the availability ofgeometric information of thousands of points on an object in a short span oftime. TLS, as a new method of surveying, may replace the use of
conventional surveying data collection techniques by faster and more
complete data collection (Boehler et al., 2003). Colombo and Marana (2002)
called these systems as natural successors to motorized total stations. It has
become an additional technique for geodetic applications (Schulz andIngensand, 2004). Some of its application areas are creation of 3D digitalmodels, 3D imaging of buildings and structures, measurement tasks,
particularly for engineering projects and cultural heritage recording. Laser
scanner has also been used in topographic mapping of quarries, mines andtunnels, scene acquisition for virtual reality modeling application and for
dimensional measurements of interiors as well as for complex shapes ofarchitecture. Dense data sets and high sampling frequency obtained from
TLS also make it suitable for structural monitoring such as structuraldeformation for risk assessment, change detection and structural model
validation. Apart from these many new applications are being targeted.
Scanning a building is among the most common and useful application ofthis technique.
Invariably, in case of a large building several scans are required tocapture the geometry of building. The individual scans of a building arereferenced onto the coordinate system of the scanner, which varies for each

53431

October 2004, Agra, India

scan. Integration of different scans is important to generate a complete 3Dmodel, as is required in problem solving. Integration of data points resulting
from different scans is carried out through the process of registration, whichattempts to bring all data points onto a common reference system. Thisreference system could be an arbitrary one or the reference system of one of
the scans. This paper discusses the significance of 3D models of buildings,
scanning procedure using TLS and method of registration adopted. The
commercially available CAD software Imageware Surfacer V10.0 has beenused for registration purpose in this paper. Finally the error of registrationand other relevant points are discussed.
2.0 AIM OF THE PAPER
The aim of this paper is to perform registration of scans taken fromdifferent positions which are obtained using the TLS. The different position
point cloud scans are required to be stitched together, i.e. registration ofscans, so that all scans can be referred onto a single co-ordinate system andcan further be used for construction of 3D model. The procedure adopted
during registration is discussed in this paper.
3.0 SIGNIFICANCE OF 3D BUILDING MODELThe TLS can be used for capturing geometry of any structure speciallyhistorical and archeological buildings. For many ancient buildings, thebuilding is the only evidence about its existence and history. There are many
structures of archeological importance which are on the verge of destruction.
3D scanning can help in archiving their structural details which may be
useful for virtual tourism, research and reconstruction in case of damage tothe structure.
3D modeling is further equally important for capturing geometry ofmodern structures. TLS can be used to generate drawings of buildings andother infrastructure on as-it-is basis. Fast data acquisition also helps inassessing the damages to structures, or distribution of debris in case ofdamage to structure after a disaster.
Thus, for conservation of old historical buildings, archaeologicalresearch, reconstruction and visualization of new structures the 3D model
can play a significant role. Prior to TLS technique the conventional methods
were used for making 3D model. These are discussed in the next section.
4.0 CONVENTIONAL METHODS
The conventional methods used in the past to capture 3D model weretheodolite angle intersection, metric photogrammetry, non-metricphotogrammetry or close range photogrammetry. The process of creating
3D models from real scenes has some well-known steps viz. data collection,
data registration, and modeling (geometry, texture, and lighting).
Conventionally, land surveying and terrestrial photography were used fordata collection. Land surveying though accurate, fails to capture a dense

54

New Technologies for Urban Safety of Mega Cities in Asia
432

ICUS Report 6

point cloud thus missing the fine details of structures. Also, it iscumbersome and error prone. The surveying measurements are imported
into CAD software for generating 3D model. In image based methods,
photogrammetric bundle adjustment is used for data registration andsoftware like Photo Modeler are employed for preparing the 3D models.
Despite the data capture being fast, conversion of photographs into a 3dmodel is not fully automatic and requires highly skilled human resource andhuge processing time.
Invention of TLS technique has eliminated several of limitations ofconventional methods and should be ideally suited for capturing accurate
and dense 3D data at high speed.
5.0 STATE OF ART ON REGISTRATION
Registration of point clouds from different scans is solved using theclassic problem of coordinate transformation. Fundamental to this iscomputation of transformation parameters i.e. scale, translation, and rotation
between two coordinate systems. This is realized by identification ofhomologous points, e.g. corners in adjacent and overlapping scans or at least
three scan ‘targets’ within each scan data. Collection of tie points and search
for the homologous points in adjacent scans can be performed automaticallyusing reflecting targets (Bornaz et al., 2002). Since the engineering objects
are usually composed of poor reflective materials (clay, soil, stones)
reflecting targets are the best option. Researchers have attempted various
techniques for registration of scanner point cloud. Besl and Mckay (1992)
developed one of the most popular methods known as iterative closest point(ICP) algorithm which is accurate and computationally efficient registrationof 3-D shapes including free-form curves and surfaces. This method is basedon finding the closest point on a geometric entity to a given point. The
iterative closest compatible point (ICCP) algorithm has been proposed inorder to reduce the search space of the ICP algorithm (Akca, 2003). Roth(1999) proposed a method that exploits the intensity information supplied by
the laser scanner. In (Dijkman and van den Heuvel, 2002) a registration
method based on parametric model fitting (cylinder and plane) is presented.
Akca (2003) presented a full automatic point cloud registration method. He
used definite template shape special targets in registration process totransform local point cloud into ground coordinate system. Algorithm isbased on cross-correlation matching method on intensity image. For
achieving better registration results, Balzani et al. (2002) used laser scanneralong with a GPS. The GPS determines the 3D coordinates of thehomologous points to georeference scans automatically even if scans arecarried out at different times and do not have large overlaps.
The literature reveals that the methods which make use of external
targets or GPS measurements on object surface yield better result and can be
automatic. However, considering field conditions it is always not possible
and also not desirable to place targets on a structure. Further, measurementof control point locations on the structure is also time consuming. In view ofRegistration of Laser Scanner Point Clouds for a Large and Complex Building
433

55

October 2004, Agra, India

this it is desired to study a method which makes use of overlap area in point
cloud for registration. The same is aim of this paper.

Figure 1: SIDBI Building, IIT Kanpur
6.0 STUDY SITE AND DATA ACQUISITIONThe Sidbi building at IIT Kanpur was chosen for study in view of its
typical shape as shown in Figure 1. The building was scanned on May 20th,
2003 using Cyrax 2500 TLS. Cyrax is a portable, 3D laser scanning systemthat captures, visualizes and models complex structures and sites with anunprecedented combination of completeness, speed, accuracy, and safety.
Cyrax 2500 scans the building using time of flight principle. The
laser pulse fired from Cyrax is reflected by the object and by measuring thetime of flight of laser pulse the laser vector from Cyrax to target point isdetermined as shown in Figure 2. Combining this vector with the coordinates of origin (within Cyrax) results in coordinate of targeted point.

Figure 2: Mechanism of TLS measurement

56

New Technologies for Urban Safety of Mega Cities in Asia
434

ICUS Report 6

The scanning mechanism of instrument ensures measurement of
thousands of points on the surface of object (Figure 2). The specifications ofscanner are listed in the Table 1. Since it is not possible to have complete
3D representation from data acquired at a single viewpoint, the scans werecarried out from five different positions around the building. The scanningstations were selected such that a part of the building should be present in
the overlap area of successive scans. No external targets were used during
scanning. Each scan has its own local coordinate system with its origin at
the instrument.
Table 1: Specification of Cyrax2500
S.No
1
2
3
4
5
6
7
8
9

Product Quality
Laser Wavelength (in nm)
Laser Classification (Class)Beam diameter at specified
Distance (Ymm at Xm)
Average Data acquisition Rate (pps)
Distance Accuracy at Specified
Distance (Ymm at Xm)
Position Accuracy at Specified
Distance (Ymm at Xm)
Angular accuracy
Distance Range
Field of view (H × V)

Product performance532
2< 6mm from 0 − 50
1,000±4mm at 50m±4mm at 50m±60micro − radians
1.5m − 100m
40 × 40 degrees

7.0 REGISTRATION METHODOLOGY
7.1 Data cleaning
Scanning with TLS results in dense data points, which contain
unwanted details also. Unwanted details are those which are not related tobuilding. Around each scan there are many objects such as lamp posts, trees
and grass which not only increase the size of the file thus creating problem
in loading and unloading, but also make moving and visualization of point
cloud difficult. Therefore as a first step unwanted point cloud were removed
from the scan (Figure 3(a) and 3(b)).

(a) Total scan taken by TLS(b) Desired portion of point cloudafter cutting unwanted details
Figure 3: Cleaning of scans

Registration of Laser Scanner Point Clouds for a Large and Complex Building
435

57

October 2004, Agra, India

The unwanted point cloud is cut using a function “circle-select points”
in Imageware Surfacer Software V10.0 and selection mode was chosen as“Points outside (delete inner)”. A selection boundary is created on portion ofpoint cloud and all the points which fall inside this closed boundary aredeleted and a new point cloud is generated in which only relevant points are
retained which lie outside the boundary. The closed boundary needs to bemade carefully so that only unwanted points are removed. This procedure isrepeated till all the unwanted portions from all the scans are removed.
7.2 Registration
Since during the scan no external targets were placed on the building,the overlapping area between two scans was considered for registration.
Some prominent features in overlapping area were earmarked forregistration. Direct registration function of Imageware Surfacer V10.0 isused for registration of five different scans of building. This function aligns
a point cloud with a geometric entity in the world coordinate system.
Parameters required for the operation are:

Mobile Entities: It is that entity which is to be moved to beregistered with the source cloud. It can be picked in the view port,
or can also be chosen by selecting its name in the dialog box.
Source Entity: It is the part of mobile entity point cloud and it tries
to align itself with the destination entity (Figure 4(a)).
Destination Entity: It is the part of that cloud with respect to whichsource point cloud tries to align (Figure 4(b)). To register scan 4 tocoordinate system of scan 5. Mobile entity is full point cloud scan4, source entity and destination entity is chosen as a part from scan
4 and 5 respectively (as shown in Figure 4). For getting accurate
results, the source cloud entity has to be a subset of the destination
entity. The outliers in the entities are deleted before using thefunction.

(a) Source entity of scan number 4(b) Destination entity of scannumber 5
Figure 4: Parameters for direct registration

58

New Technologies for Urban Safety of Mega Cities in Asia
436

ICUS Report 6Tolerance: The tolerance for acceptable registration error isentered as 0.001.
Registration Option: There are two registration options:
Refinement or best possible. Best possible registration option is
selected.
Registration Mode: There are four types of registration modes: No
Constraint, Constraint X, Constraint Y, or Constraint Z. No
constraint mode is selected. The source point cloud can be rotated
and translated in all degrees of freedom.

After inputting all these parameters in direct registration function, theselected source point cloud is rotated and translated so that the mean squaredistance between the cloud and the destination geometric entity is
minimized and is within the specified tolerance, if possible. The registration
system works on the assumption that each point in the source cloud has acorresponding point on the destination entity.
All scans were registered with respect to the coordinate system of scan
1. This was realized by registering scan 2 with the scan 1. Then point cloudsof scan 1 and 2 are merged into a single registered point cloud using afunction “merge point cloud”. The scan 3 is registered with already mergedscan 1-2. This results in single point cloud of scans 1-2-3. Separately, scan 4
and scan 5 are registered and merged into a single point cloud. The point
cloud 4-5 is then registered with the point cloud 1-2-3 using overlaps
between scan 5 and scan 1. This was done to curtail accumulation ofregistration errors and also the overlap between 3 and 4 was insignificant.
Finally all point clouds are merged into one single point cloud with all thescans registered on the co-ordinate system of scan 1. Figure 5 shows theregistered point cloud scans.

Registration of Laser Scanner Point Clouds for a Large and Complex Building
437

59

October 2004, Agra, India(a)All scans registered(b) All scans registered (top view)
Figure 5: Registered point clouds of SIDBI building
7.3 Accuracy in registration
Registration was carried out very carefully considering every minutedetail in selecting the mobile and destination entity. Also, the spurious
points, e.g. unwanted details and outliers were removed prior to registration.
The Root Mean Square (RMS) value reported during the registration bysoftware, i.e. the accuracy with which the source entity of one scan translate,rotate and align itself with the destination entity of another scan, are shownin Table 2.
Table 2: RMS error during registration
S.No.
1
2
3
4

60

Scan number
Scan 1 and 2
Registered scan 1-2 and 3
Scan 4 and 5
Registered scan 1-2-3 andregistered scan 5-4

Registered RMS error in cm
0.149
0.192
0.202
0.197

New Technologies for Urban Safety of Mega Cities in Asia
438

ICUS Report 6

It is important to note that the RMS error as computed by software is
the accuracy with which the source point cloud entity gets itself aligned withthe destination point cloud entity during the direct registration process. It is
not the accuracy of full registration of one point cloud with another point
cloud. This RMS error is therefore misleading. This is evident when two fullpoint clouds of scan 1 and scan 2 are visualized after aligning; the edges of
balcony and walls are seen at a distance of an average 25.04 cm apart in twoscans. Similarly, an average error of 19.00 cm is observed in scan 4 andscan 5. The basis of this latter accuracy determination is measuring distance
between two points which represent the same object on the building but
belong to two different scans. The average difference in their position isreported by its arithmetic mean for 10-15 points. Selecting the same point in
two registered scans is not an easy task unless they appear distinctly
separate and are identifiable. Therefore, a better method for determination of
accuracy could be by comparing scans with total station measurement ofbuilding.
8.0 DISCUSSIONSWith TLS the amount of data obtained is huge. There are more than alakhs points in each scan, including several redundant data points, which
can be used efficiently to make 3D model. The scanner scans everythingthat comes within its field of view (FOV), including the unwanted details.
The unwanted data points cause problem in handling the data files. Since notargets are desirable to be placed while scanning the building, a properconsideration should be given to the overlapping portion between two scans.
Improper selection of scan stations results in problem in choosing source
entity and destination entity required for registration. Yet another problem isof no data points in some parts of building due to shadows of trees, lamp
post and other projected corners of the building. It is unavoidable to get ridof these obstructions. Moreover scanning stations should be chosen in sucha way to avoid maximum of these obstructions, which will help in reducing
the problem of shadowing.
9.0 CONCLUSION AND RECOMMENDATIONS
For any large and complex building scanning has to be carried out
from different viewpoints to get a complete view of the building. In thispaper, registration of these different position scans is carried out considering
the overlapping regions in between the different scans. Based on theexperience of registering the scan it can be concluded that just scanning thebuilding does not solve the problem. The unwanted details and problem of
the shadow can be solved by following a proper strategy before scanning. It
is recommended to scan in such a way that the effect of projected area on
scanning will be least. It would be better to carry out a detail reconnaissanceof the area. As the use of targets is not always feasible and desirable during
scanning, it is better to have a good overlap between successive scans. Only
five scans of a large building, as in the present case, are not sufficient.

Registration of Laser Scanner Point Clouds for a Large and Complex Building
439

61

October 2004, Agra, India

Hence, to reduce the time and energy during post processing of data, it
is essential to scan following a proper strategy. Else, the time saved during
data acquisition will be annihilated in post processing and the desired
benefit of time efficiency of this new technique will be no longer be evident.
ACKNOWLEDGMENT
Elcome Technologies Pvt. Ltd. provided the Cyrax 2500 instrument
for scanning and helped in scanning the site. Registration of point clouds
was done in CAD laboratory, IIT Kanpur and Mr. Surya Prakash, project
associate in CAD lab; IIT Kanpur provided support during learning andregistering the scans in Imagerware Surfacer V10.0 software.
REFERENCES
Akca, D., September 2003. Full automatic registration of laser scanner
point clouds. Optical 3-D Measurement Techniques VI, Zurich, 1, 330–
337.
Balzani, M., Pellegrinelli, A., N. Perfetti, P. R., Uccelli, F., Tralli, S.,
September 2002. Cyrax tm 2500 laser scanner and g.p.s. operational
flexibility: From detailed close range surveying, to urban scale
surveying. ISPRS Commission V, Symposium 2002.
Besl, P. J., Mckay, N. D., February 1992. A method of registration of 3d
shapes. IEEE Transaction on Pattern Analysis and Machine Intelligence
14 (2), 239–256.
Boehler, W., Vicent, M. B., Marbs, A., 2003. Investigating laser scanner
accuracy. XIXth CIPA Symposium.
Bornaz, L., Lingua, A., Rinaudo, F., September 2002. Engineering andenvironmental applications of laser scanner techniques. ISPRS
Commission III, Symposium 2002.
Colombo, L., Marana, B., May 2002. 3d building models using laser
scanning. GIM International 16 (5), 32–35.
Dijkman, S., van den Heuvel, F., 2002. Semi automatic registration of laser
scanner data. IAPRS XXXIV (5).
Roth, G., 1999. Registration two Overlapping Range Images Proc. of
second int. conference on 3d digital imaging and modeling, ottawa..
Schulz, T., Ingensand, H., May 2004. Terrestrial laser scanninginvestigations and applications for high precision scanning. FIG
Working Week 2004.

62

New Technologies for Urban Safety of Mega Cities in Asia
440

EXTRACTION AND 3D VISUALIZATION
OF TREES IN URBAN ENVIRONMENTYOSHIFUMI YASUOKA, YOSUKE YAMAGISHI, TAO GUO
AND TAKAHIRO ENDO
Institute of Industrial Science, University of Tokyo, Japanyyasuoka@iis.u-tokyo.ac.jp
ABSTRACTDigital city models are required for many applications such as urban
microclimate simulation, traffic navigation and landscape planning. The
existing 3D digital city models, however, mostly target only on modelingbuildings although vegetation plays an important role in the urban
environment. This research investigates the 3D digital city model with bothof building and trees by extracting individual trees from high resolution
IKONOS imagery together with Airborne Laser Scanner (ALS) data and bycoupling them with a tree growth model to simulate the growth of trees.
Finally, the simulated trees are integrated with the buildings modeled also
from IKONOS imagery and ALS data to represent a more realistic 3D
urban environment.
1.0 INTRODUCTION
Urban structure is one of the most essential factors which define thecharacteristics of urban safety and environment. Land use patterns or
distribution of buildings and vegetations are infrastructural information toassess, simulate and predict urban environment and disasters. In particular,
three-dimensional information on the distribution of buildings andvegetations, 3D model, plays a key role in microclimate simulation, traffic
navigation or landscape planning. It is, however, not easy to model 3D
structures in urban area since they are very much complicated. This study
investigates the 3D modeling of urban structures with new remote sensing
technologies including high spatial resolution observation from satellite andheight observation from airborne laser scanner.
There have been several approaches to extract 3D information fromremotely sensed data. Arial photographs were conventionally used in urban
3D modeling. However, it usually needs a lot of human power andprocessing time. Due to rapid improvement of spatial resolution satellite
images have been recently used to produce urban 3D models. For example,
Haala and Brenner (1999) integrated multi-spectral imagery and laser
altimeter data for the extraction of buildings, trees and grass-covered areas,
and for the reconstruction of buildings using laser data and 2D ground plan
information. Also Guo and Yasuoka. (2002) combined IKONOS imagery
and Airborne Laser Scanner (ALS) data to extract urban 3D information.
The existing 3D city models using remote sensing data, however,mostly focus on modeling of buildings. Although vegetation plays an83441

October 2004, Agra, India

important role in urban environment as well as buildings it has not beenmodeled properly since vegetation structure is complicated to extract fromsatellite data and not easy to model. This research develops a method to
extract and model 3D structures of trees as well as buildings from remotelysensed data. First trees were extracted from high spatial resolution satellite(IKONOS) image and Airborne Laser Scanning (ALS) data, and then trees
in urban environment were modeled in 3D format by integrating the tree
data derived from remote sensing data and 3D tree growth model. Finallythe modeled trees were integrated with buildings also extracted fromIKONOS image and ALS data. The proposed method was applied to Tokyo
urban area, and the realistic landscape was demonstrated.
2.0 DATA DESCRIPTION AND TEST SITE
Shinjuku area in Tokyo was selected as a test site since the area hasvery complicated urban structures and it was composed of many different
types of buildings and trees. For the test site IKONOS data was used for
detail land cover classification including buildings, trees and bare ground,and also ALS data was used for land surface modeling. Table 1 summarizes
the data set used in this research. Figure 1 and Figure 2 show IKONOS
image and Digital Surface Model (DSM) derived from the ALS data.
Table 1: Data set

Date
Spatialresolution
Accuracy

IKONOS
2001.11.4
multispectral:4m/pixel
panchromatic:1m/pixel―

ALS
2000.2.23
Around 10cm
±15cm(vertical direction)

Figure 1: IKONOS panchromatic image Figure 2: DSM derived from ALS

84

New Technologies for Urban Safety of Mega Cities in Asia
442

ICUS Report 6

3.0 METHODOLOGYFirst, Normalized Differential Vegetation Index (NDVI) was
calculated from IKONOS image, and the pixel that had large NDVI value
was extracted as tree areas. Next, the tree position was detected, and the tree
size (age) was evaluated by the detected canopy size. Finally 3D tree modelin urban environment was developed using 3D tree growth model. In thisresearch the tree detection scheme assumed the following conditions for thetree structures:
The tree position is the center of the tree image from the top view.
NDVI value increases as approaching to the center of a tree.
Canopy of a tree may be approximated by a circle.
An example of a tree in IKONOS image and the corresponding NDVI
is illustrated in Fig. 3.
high

A tree

NDVI

low

Figure 3: the condition of NDVI in a tree
3.1 Detection of tree positions
A schematic flow for the detection of tree position is shown in
Figure 4 and an example of tree position detection is illustrated in Fig. 5.
First, NDVI was calculated from IKONOS image to separate vegetation
areas and non-vegetation areas. The area of high NDVI value is extracted asvegetation area. Then the ALS data was mask for the vegetation area (high
NDVI area) and trees were extracted for high ALS value. That is, the tree isdefined as the area of high NDVI and high ALS value area (Figure 5-b).
The position of each tree was detected for the extracted tree area.
First, a skeleton of the extracted tree area was calculated based on theassumption that the tree position is the center of the image from the top
view. Figure 5-c was obtained by skeletoning the image in Figure 5-b. Eachpixel on the skeleton line was given NDVI value, and Local Maximum
Filter (Wulder, et. al., 2000) was applied to the NDVI skeleton image todetect the canopy top (Figure 5-d).
3.2 3D Modeling of trees
Figure 6 shows a flow of modeling of trees in 3D. First, 3D treemodel was generated using natFX and 3D modeling software. NatFX was a
3D tree growth model developed based on AMAP (Atelier of Modeling ofArchitecture of Plants). It can model a lot of types of plants, including

Extraction and 3D Visualization of Trees in Urban Environment
443

85

October 2004, Agra, India

ALS Data

IKONOS Image

DSM

NDVI
Tree area
Skeltonizing

Local maximum Filter
Tree position

Figure 4: Flow of the detecting tree positions
a

b

c

d

a: IKONOS panchromatic image
c: the skeleton line of the tree areab: the extracted tree aread: the detected tree positions(white points)
Figure 5: The result of tree position detection

flowers, bushes and trees and can generate 3D models of a given plant at
different ages and at different seasons (Figure 7). In this model, the tree age
was necessary to generate 3D tree model. In this research tree age wasestimated from the canopy size of the detected trees.
First, template matching was operated to estimate the diameter of the
canopy of the detected tree on the basis of assumption 3. The diameter of86

New Technologies for Urban Safety of Mega Cities in Asia
444

ICUS Report 6

the circle that was best matched to the canopy was defined as a canopy
diameter of the tree.
The tree growth was simulated to estimate the age of tree from thediameter of canopy. Figure 8 shows the relation between the diameter of the
canopy and the age. The age of tree was estimated from the canopy diameterof the tree.
position data

3D tree growth model

tree area

Template matching

Database of 3D tree model

Canopy size

Mapping of 3D tree model on IKONOS image

3D tree model in urban environment

Figure 6: Flow of 3D modeling of trees

Zelkova serrata

Ginkgo biloba

Figure 7: 3D tree model
Diameter of canopy

20
15
10
5
0
0

10

20

30
age

40

50

Figure 8: The relation between diameter of canopy and age(zelkova serrata)
Finally 3D tree model for the estimated age was mapped at thedetected position in the IKONOS image. The data of tree species were got
from the field survey and the ledger of greening roads, which is made byTokyo Metropolitan Bureau of Construction.

Extraction and 3D Visualization of Trees in Urban Environment
445

87

October 2004, Agra, India

3.3 Integration of tree model with 3D building model
3D building model was produced from the same data set following thealgorithms developed by Tao, et.al. (2002). The framework of the approachcontains the following steps: (1) segmentation of raised objects from groundto generate normalized digital surface model, (2) ortho-rectify images andderive edge etc. clues, (3) building blob detection by multiple height bins,and (4) building contour detection using balloon model. This scheme
enables to estimate the building structures with high accuracy, and theestimation error of the 3D buildings was below 1m in average. Figure 10
illustrates an example of the 3D city model integrating building and trees.

Figure 10: 3D city model including buildings and trees
4.0 CONCLUSION
A method for 3D digital city modeling was developed with remotelysensed data. 3D digital city is one of the key elements to assess and predict
environment and disasters. This research may provide an efficient tool to
produce more realistic model with buildings and trees.
REFERENCES
Haala, N and Brenner C,. 1999. Extraction of building and trees in urban
environments. ISPRS Journal of Photography & Remote Sensing, 54,
130-137.
Wulder, M., Niemann, K.O and Goodenough D.G, 2000. Local Maximum
Filtering for the Extraction of Tree Locations and Basal Area from HighSpatial Resolution Imagery. Remote sensing of Environment, 73:103114.
Tao, G. and Yasuoka Y. 2002. Data fusion of high-resolution satellite
images and airborne laser scanning data for building detection in urban
environment. Proc. of SPIE Conference on Image Processing and Pattern
Recognition in Remote Sensing, Vol. 4898, 120-130.

88

New Technologies for Urban Safety of Mega Cities in Asia
446

GROUND CONTROL FOR THE
GEOMETRIC CORRECTION OF
REMOTELY SENSED IMAGERY:REQUIREMENTS AND ISSUES IN INDIA
S. K. KATIYAR1, ONKAR DIKSHIT2 AND KRISHNA KUMAR3
1
Civil Engineering Department, M.A.N.I.T., Bhopal
2
Civil Engineering Department, I. I. T. Kanpur, Kanpur
3
M.N.N.I.T., Allahabadskatiyar7@rediffmail.com
ABSTRACT
Conventionally ground control (GCPs) are derived from maps, but inthe developing countries most of the existing maps are out of date due tolarge population growth, rapid changes in urban areas and economic
development. Global Positioning System (GPS) has emerged as a very
powerful tool for the acquisition of GCPs with the desired accuracy. In
India full potential of GPS technology could not be utilized by the civilian
users for the mapping requirements in Indian datum, due to restriction
policies of the Government of India. This research paper presents
investigations on the geometric correction accuracy of IRS-1C/D LISS-III
and PAN sensor imagery using 1:50,000 and 1:25,000 scale SOI map
derived and GPS derived GCP coordinates. Limitations of map derived
GCPs and problems in the transformation of GPS coordinates into Indian
datum are also investigated.
1.0 INTRODUCTION
Satellite images are vital tool in various applications like land use andland cover mapping, Geographic Information System (GIS) etc. Remotelysensed images are often considered as maps of the radiometric properties ofthe earth’s surface. However, these are not usually map-like. A variety offactors involved in the process of image acquisition, introduce geometricdistortions, which are removed by the process of geometric correction. As
technology progresses, the raster picture element (pixel) resolution ofdigitally acquired remotely sensed imagery continue to become finer inspatial resolution. This dictates the need of ground control points (GCPs)
with increased spatial accuracy to geometrically correct remotely sensed
data from high resolution satellites like SPOT, IRS-1C/D, RESOURCESAT(IRS-P6) and IKONOS.
The current status of world mapping leaves much to be desired;especially developing countries where most of the existing maps andmedium scale maps are out of date. Because of large population growth,
rapid change in urban areas and economic development, the topographic
maps become rapidly out of date. The data capture using conventional
methods (Surveying and Photogrammetry) for topographic mapping and89447

October 2004, Agra, India

map updating at small and medium scale takes a long time to complete thetasks involved. The most significant development of the twentieth century
for navigators was the development of the Global Positioning System (GPS).
GPS has revolutionized positioning concepts on land, at sea, in the air and inspace. It has got wide range navigational, geodetic, geophysical, military,marine and social applications. GPS can provide an alternative to the groundcontrol survey methods for the poorly mapped areas, which could not bemapped using conventional methods. Differential mode of GPS (DGPS) has
capability of providing very precise coordinates of any point up to
centimeter level accuracy.
A major concern in the use of GPS data for various applications is theintegration of GPS coordinates with the local datum map coordinates, if thecenter of Earth spheroid model used for the map preparation has
considerable offset from the center of the GPS Earth spheroid model (WGS84). Because of this coordinates measured on two different ellipsoids will
not be same for any position. For various practical applications like map
updating and comparison with the existing maps, GPS coordinates are
required to be transformed into local datum. In particular, in cadastral andengineering surveys, such transformations are normally the norm rather thanthe exception.
2.0 GCP ACQUISITION SOURCES IN INDIAIn India the conventional sources of GCPs are Survey of India (SOI)
maps. The SOI maps are available to civilian users on two different scales
1:50,000 and 1:25,000. The 1:25,000 scale maps have only about 20%
coverage. Thus, 1:50,000 scale maps appear to be ideally suited for deriving
GCP coordinates as these are available for the whole country. Also,
1:50,000 scale is the primary surveying scale from which the 1:25,000 scale
maps have been compiled (Shiva Kumar, 1998). These SOI maps are basedon old-field survey and having coordinates in Indian datum. The new seriesof maps having coordinate grids in Indian as well as WGS-84 datum has
been also announced by SOI. GPS could provide GCPs with the desired
accuracy. After the termination of selective availability of GPS signals, evena hand-held GPS could provide sub pixel level accuracy for the geometriccorrection of Indian Remote Sensing satellite (IRS) images (Katiyar et al.,
2002; Katiyar et al., 2003).
3.0 ISSUES RELATED TO THE SOI TOPOGRAPHIC MAPS AND
INDIAN DATUMThe SOI maps prepared in Indian Geodetic Datum are based on
Everest spheroid which is a local geodetic datum and best fits to certain
extent the Indian subcontinent. It is not a geocentric ellipsoid and its origin
is far away from the geocentre i.e. center of gravity of the Earth (Agrawal,
1997). The geodetic coordinates based on Everest spheroid differ
considerably as compared to WGS-84 and other international ellipsoids. In
India, the topographic maps available to a general user are in local geodetic

90

New Technologies for Urban Safety of Mega Cities in Asia
448

ICUS Report 6

datum and GPS coordinates of a point observed in WGS-84 datum will
differ considerably from the corresponding map coordinates. The main
problem with the use of GPS data is that the transformation parameters
between WGS-84 and Indian datum which are not available to the civilian
users. Recently SOI has announced that the new series of SOI maps will
also have WGS-84 coordinates along with the Indian datum coordinates.
However we should not ignore the inherent errors of map-making process(Cook and Pinder, 1996; Thapa, 1992). Further, the SOI map sheets areprojected individually with Polyconic map projection origin at the center ofmap sheet. This creates problems in joining different map sheets andrectification of full scenes of remotely sensed images.
GPS is considered to be the best available technique for deriving the
precise GCP coordinates for the geometric correction of remotely sensed
imagery (Clavet, 1993; Cook and Pinder, 1996; Kardoulas et al., 1996).
GPS can prove to be an important tool for GCP data collection in a country
like India, where large-scale maps are not available and even 1:25,000 scale
Survey of India (SOI) topographic maps have only 20% area coverage (Siva
Kumar, 1998). The main problem with the GPS coordinates is the lack ofprecise transformation parameters between WGS-84 and Indian datum,
which is required for the integration of GPS data with the local datum maps.
In Indian context various crucial issues related to the GCP acquisition forthe high resolution IRS images are as below:

Accuracy of maps
Availability of WGS-84 to Indian
parameters
Effects of Polyconic map projection

datum

transformation

4.0 STUDY SITES AND DATA RESOURCES
This research work was carried out for three different study sites
namely Bhopal, Kanpur and Lucknow. These sites were selected after
taking into consideration various aspects like availability of good GCP
features and base maps, convenience for GPS field work and GCP coveragefor the full scene. The IRS-1C/1D satellite LISS-III and PAN sensor images
were used for the investigations. The coordinates of GCPs identified on themaps were also read in the WGS-84 datum, using two different category
GPS receivers (DGPS receiver model SR530 and hand-held stand-alone
mode receiver model GS5 as per specifications given in Table 1.
5.0 METHODOLOGY
Point pairing techniques was used for the assessment of errors in the
GCP determination from the SOI maps. The GCP based geometriccorrection accuracy was determined in the ILWIS software using GCPs
from SOI maps and GPS. Effects of different map projections and datums
were also investigated by finding projected distances between widelydistributed GCPs in the study sites.

Ground Control for the Geometric Correction of Remotely Sensed Imagery
449

91

October 2004, Agra, India

6.0 DISCUSSION OF RESULTS
The point pairing analysis results for the different scale SOI maps ofdifferent study sites are shown in Table 2. This analysis has shown large
variability in the coordinates of derived from maps. The coordinates derived
from GPS and SOI maps have large difference and these differences for two
different study sites are given in Table 3. Because of the large difference ofIndian datum and corresponding WGS-84 coordinates, the transformation of
GPS derived coordinates to Indian datum is essential, if used in integration
with different maps like cadastral, land use etc. maps. The geometriccorrection accuracy of IRS, PAN sensor images were investigated by GCPs
from different sources and accuracy of each case is given in Table 4. The
projected distances on Everest ellipsoid in Polyconic and UTM map
projections are given in Table 5. These have shown that different map
projections will have different projected distances at full scene level andthese are significant in high-resolution images.
Table 1: Specifications of GPS receivers used in the investigations
GPS receivermodel and type

Available GPS
signal channels

Observationmode

Accuracy

Dual frequency
DGPS receivermodel, SR530 ofLeica Geosystems

12 channel dual
Differential phase mm level
frequency L1 and L2 Differential code 30 cm
of C/A-code andcarrier phase

Hand-held standalone receivermodel, GS5 ofLeica Geosystems
AG

12 channel L1 C/Acode with parallel
automatic selection

Stand-alone mode 3 to 5 m

Table 2: Distance errors in point-pair analysis for map derived GCP
coordinates
S.
No.
1
2
3
4
5

92

Source of map derived GCPs used for Range of distancepoint-pair analysis
error absolute value(m)
1: 50,000 scale SOI maps of Bhopal area
25 to 130
1: 50,000 scale SOI maps of Kanpur area 30 to 150
1: 50,000 scale SOI maps of Lucknow area 20 to 100
1: 25,000 scale SOI maps of Kanpur area 15 to 90
1: 25,000 scale SOI maps of Lucknow area 15 to 80

New Technologies for Urban Safety of Mega Cities in Asia
450

ICUS Report 6

Table 3: Difference between WGS-84 datum and map derived Indian datum
planimetric coordinates for the study sites
Bhopal1:50,000
GCP scale map
No. 
(s)(s)
1-3.54 3.76
2
-2.76 4.03
3-0.99 5.66
40.53 3.32
5-1.67 3.62
6
-0.86 4.54
7
-1.61 3.95
8-0.53 2.49
9-0.49 2.54
10
-0.53 4.64
11
-1.27 2.90
12-2.36 3.72
13
-1.23 3.43
14
-1.18 4.01
15
-1.07 4.55

Kanpur
1:50,000
scale map


(s)
(s)
-1.41 5.06
-2.37 5.87
-0.92 7.59
-0.06 6.06
-3.93 5.99
-3.07 5.88
-0.06 6.87
-0.34 6.14
-0.68 6.39
-1.19 6.41
-0.15 6.39
-1.42 6.03
-1.36 8.03
0.55 6.07-1.47 5.37

KanpurLucknow
1:25,000
1:50,000
scale map scale map


 
(s)
(s)
(s)
(s)
-1.31 6.05 -1.26 7.34
-1.21 6.58 -0.54 6.61
1.67 7.18 -0.50 7.44
-1.60 7.97 -1.28 7.19
-0.90 6.17 -0.57 8.29
-0.06 6.11 -1.14 6.90
-0.41 4.35 0.04 7.41
0.16 6.90 -0.20 7.22
-0.98 6.01 -1.07 8.51
-0.46 5.16 0.52 6.30
-0.74 5.11 0.22 6.99
-1.69 6.71 -0.73 7.50
-0.12 6.96 -0.57 6.01
1.13 6.94 -1.77 5.99
-1.58 6.79 -0.77 6.93

Lucknow
1:25,000
scale map


(s)
(s)
-1.54 7.97
-0.74 5.11
-1.09 5.57
-1.69 5.15
-1.33 6.01
-0.72 5.14
-0.32 5.55
-0.25 5.73
-1.63 6.27
-0.57 4.76
-0.38 4.88
-0.53 5.40
-0.09 5.96
-1.98 4.85
-1.23 5.98

Table 4: RMS errors in terms of the corresponding image pixels ofgeometrically corrected LISS-III and PAN images, using GCPs
from maps and GPS.
Details of corrected
image

1:50, 000 1:25, 000 Hand-held DGPS
scale map scale map GPS GCPs GCPs
GCPs
GCPs
Bhopal PAN image
4.41
NA
0.44
0.54
Kanpur PAN image
5.91
2.87
0.55
0.75
Lucknow PAN image
3.37
2.39
1.14
1.07
Bhopal LISS-III image
1.22
NA
0.30
0.32
Kanpur LISS-III image
1.77
1.34
0.54
0.70
Lucknow LISS-III image
1.10
1.05
0.56
0.65

Ground Control for the Geometric Correction of Remotely Sensed Imagery
451

93

October 2004, Agra, India

Table 5: Distances between GCPs, using different map projections andearth ellipsoids
Point
d1 (m)
d2 (m)
d3 (m)(d1- d2)(d2- d3)
pair no.
(m)(m)
12495.00
2494.012495.86
0.99
-1.85
2
3986.41
3986.833988.28
-0.41
-1.45
3
7710.167710.817714.27
-0.65
-3.46
4
5436.635436.885439.64
-0.25
-2.76
5
8090.878090.30
8094.04
0.57
-3.73
6
3304.323305.313306.59
-0.99
-1.28
7
8945.028943.64
8948.18
1.37
-4.53
8
10380.26 10378.25 10382.28
2.01
-4.04
9
5038.145037.045039.76
1.10
-2.72
10
8090.878090.30
8094.04
0.57
-3.73
11
1805.12
1804.83
1806.01
0.29
-1.17
12
5345.615346.725348.34
-1.11
-1.61
13
4444.714444.484446.04
0.23
-1.55
14
13035.40 13036.40 13041.56
-0.99
-5.16
15
20870.69 20871.07 20880.25
-0.38
-9.18
16
26088.75 26087.75 26098.11
0.99-10.351780904.79 80903.61 80934.07
1.18-30.461856950.25 56947.68 56970.00
2.57-22.321947500.49 47500.34 47519.17
0.15-18.832067840.62 67840.21 67866.53
0.42-26.332198876.87 98877.15 98915.51-0.28-38.362274898.68 74898.93 74926.99-0.25-28.07d1
Distance computed from UTM map projection coordinates in WGS84 datum
Distance computed from UTM map projection coordinates in Indian
d2
datum
d3
Distance computed from Polyconic map projection coordinates inIndian datum, using projection origin at LISS-III scene center
7.0 CONCLUSIONS
Based on the investigations of present research work following
conclusions can be drawn:




94

Map derived GCP coordinates should not be used for the geometriccorrection of modern age high-resolution images from IRS-1C/1D,
IRS-P6 or any other high-resolution sensor. The GCP coordinatescollected from hand held GPS receiver would suffice the sub-pixel
accuracy requirements even for IRS, PAN sensor images.
In the use of GPS data, availability of transformation parameters
between WGS-84 to Indian datum is a big problem at least forcivilian users.

New Technologies for Urban Safety of Mega Cities in Asia
452

ICUS Report 6The declared new series of SOI maps for WGS-84 coordinates will
not make any difference for high-resolution image applications. Thisis due to inherent errors of map-making process.
Polyconic map projection is not appropriate for the image
rectification and India requires appropriate map projection forsatellite image applications.
In view of the developments in satellite geodesy, efforts are neededfrom SOI for redefinition of Indian datum by selecting geocentric
ellipsoid and appropriate map projection for the new series of
topographic maps.

REFERENCES
Agrawal, N.K., 1997, WGS 84 and GPS. International Conference on
Remote Sensing and GIS/GPS. June 18-21, Jawaharlal Nehru
Technological University , Hyderabad.
Baveja, S. D., Kapur, R. K., and Mohan, R., 1994. Transformation
Parameters between Indian Datum and World Geodetic Systems (WGS72 and WGS-84): An Objective Analysis. Proceedings of 14th INCA
Congress at Bangalore (India), 28th Nov. 1994.
Clavet, D., Lassere, M. and Pouliot, J., 1993. GPS control for 1:50,000 –scale topographic mapping from satellite images. PhotogrammetricEngineering and Remote Sensing, Vol. 59, No. 1, pp. 107-111.
Cook, A. E. and Pinder III, J. E., 1996. Relative accuracy of rectifications
using coordinates determined from maps and the global positioning
system. Photogrammetric Engineering and Remote Sensing, Vol. 62, No.
1, pp. 73-77.
Kardoulas, N. G., Bird, A. C. and Lawan, A. I., 1996. Geometric correctionof SPOT and Landsat imagery: A comparison of map- and GPS- derived
control points. Photogrammetric Engineering & Remote Sensing, Vol.
62, No. 10, pp. 1173-1177.
Katiyar, S.K., Dikshit, O. and Kumar, K., 2002. GPS for the geometriccorrection of remotely sensed imagery: Possibilities after termination of
SA. Proceedings of The Asian GPS Conference, CSDMS, New Delhi,
24-25 October, 2002., pp.57-62.
Katiyar, S.K., Dikshit, O. and Kumar, K., 2003. GPS autonomous mode forsatellite imagery geocoding: Benefits of low-cost hand-held GPS. GIM
International, Vol. 17, No. 6, pp. 29-31.
Shiva Kumar, R., 1998. An integrated multi-source digital topographic
database for India. Ph.D. thesis, Deptt. Of Civil Engineering , I.I.T.
Delhi.
Singh, S. K., 2002. Coordinate transformation between Everest and WGS84
datums- A parametric approach. The Asian GPS Conference, CSDMS,
New Delhi, 24-25 October, 2002.
Thapa, K. and Bossler, J., 1992. Accuracy of spatial data used in
geographic information systems. Photogrammetric Engineering andRemote Sensing, Vol. 58, No. 6, pp. 835-841.

Ground Control for the Geometric Correction of Remotely Sensed Imagery
453

95

INTERNET GIS BASED MUNICIPALINFORATION SYSTEM: A CASE STUDY OF
DEHRADUN MUNICIPAL AREA
1

1

SURENDER SINGH AND 2B. S. SOKHI
M.Tech. Trainee, Head, Human Settlement Analysis Group
Indian Institute of Remote Sensing, Dehradun, India
surenderahlawat@hotmail.com
2

ABSTRACTThe present study has been undertaken to demonstrate the usefulness
of Remote Sensing, Internet Geographical Information System (Internet
GIS) and Global Positioning System (GPS) techniques for Land use/ Land
cover mapping and to locate the facilities and Points of interest of the client,accurately on the base map for further analysis and for the making anddevelopment of the website. To attain the goal of this project three tiers ofInternet interaction are defined as client, middleware, and server. It will be
discussed where Municipal Information System (MIS) components fit within
this framework. In the last, GIS based queries are supposed to be provided
at the client side Via Internet to provide information with ease and withselection.
The broad aim of this study is to apply Remote Sensing, Internet
Geographical Information System and Global Positioning Systemtechnology. Remote Sensing technology will be applied for the generation of
Spatial Data, Internet GIS / Geographical Information System will be used
to analyse the data and for providing selected inputs for the formation as
well as for the development of website and Global Positioning System will
be used to give accurate geographical location of the Facilities / Points ofInterest (POI) of the client. In last phase, by using all the technologies, anInternet based Dehradun Municipal Information System (DMIS) will be
developed. For this purpose an InternetGIS based conceptual model for
Municipal Information Database is discussed in this study.
1.0 INTRODUCTION
Municipalities are few of the important tiers of local Government. The
municipal bodies have a fairly comprehensive range of functional
responsibilities and regulatory powers within their boundaries including
health, accessibility / transport, primary education, garbage management,water supply, sewerage, planning and development control. Publicorganizations like municipalities experience a rapidly changing politicalenvironment that can cause radical differences in the way public employee'swork.
In the last 30 years computers have undergone a marked revolution.
Spectacular innovations in new spheres of applications areas are taking

97454

October 2004, Agra, India

place with the new development of the hardware software technology.
Computerisation has marked a new era in human history by these
innovations and applications that cover now almost every sphere of humanlife and his all activities (Quium and Shahidul, 1992)
However, the introduction of GIS technology involved the complex
processes of managing municipal functions (Campbell, 1991). The
computer system can facilitate Municipal Information System (MIS) toallow easy storage, updating, retrieval and mapping of a wide range of
information related to planning and management of municipal functions.
2.0 WHAT IS INTERNET GIS?
Internet GIS is a network-centric GIS tool that uses Internet as a majormeans to access and transmit distributed data and analysis tool modules, andto conduct analysis and visualization. Internet GIS is a special GIS tool thatuses Internet as a means to access and transmit remote data, conduct
analysis and make GIS presentation. Internet based geographical dataservices involve management spatial and non-spatial (attribute) data.
Geographic Information System (GIS) has come to be an indispensable tool
for analysing and managing spatial data.
Internet has been changing the ways of data access, sharing anddissemination. It is further changing the means of analysis and visualizationof Geographic Information Systems (GIS). Internet GIS is rapidly evolving
as Internet and Web technologies change. We seriously look at the need forthe integration of the Internet and GIS and how its implementation is
emerging as the fastest developing application for the web.
Internet GIS is a Geographic Information System (GIS) distributed
across a computer network to integrate, disseminate, and communicate
geographic information visually on the World Wide Web (Edward, 2000,
URL). In performing the GIS analysis tasks, this service is similar to the
Client-Server architecture of the Web. The geo-processing breaks down into
a server-side and client-side task that make the users will be able to access,manipulate and retrieve the GIS data from their browser without purchasing
proprietary GIS software.
Good decisions require good information. The operation level ofgovernment (the tax assessors, building inspectors, the meter readers etc.)
contains of the people who work with and depend on data, daily to performtheir tasks. If the information is inaccurate or out of date then their jobs are
difficult to perform. Not all of those data that are created by the operations
level of the municipality however are needed at the management level.
Managers generally need summary information of the operational data.
Instead of house-by-house or parcel-by-parcel data, managers needaggregate information. Even fewer data are needed for policy purposes lessdetailed but more integration, aggregation and flexibility are needed to meetthe ever-changing information needs at the policy level.

98

New Technologies for Urban Safety of Mega Cities in Asia
455

ICUS Report 6

Internet-based GIS users can use a Web browser to navigate maps anddo basic spatial analysis. A user enters specifications such as location,thematic layers, or searching requests on the web page to set up theenvironment for mapping or searching. Users can also click buttons to start
display commands such as zoom in, zoom out, identify, pan, query, etc. The
requests from user will be sent to clients by way of HTML forms. The form
is passed to the web server. A gateway at the web server passes the request
to a GIS server. For instance, the gateway could pass the request in the formof HTML to an Arc IMS Server. The Arc IMS Server then generates agraphic file that will be converted to a GIF image or JPEG image. The GIF
or JPEG image is later sent back to the client and viewed by the users with astandard web browser.
The goal then in developing information system is to design onceneeded at the operational level of the municipality, but also with thenecessary standard and flexibility to allow the data to be integrated withother data in different functions of the organisations and aggregated insummary form for assimilation at the management and policy level. Data
processor should strive to develop system that not only improve themunicipality, but can also serve the managers and policy makers in
improving decision-making, planning and policy analysis. An InternetGIS
based Municipal Information System (MIS) can facilitate or satisfy theabove-mentioned requirement of the municipality.
3.0 PUBLIC PARTICIPATION IN INTERNET MIS
Increased public involvement in the definition and analysis ofquestions tied to location and geography is the domain of Internet based
Municipal Information System (MIS), which is a type of Public
Participation GIS (PPGIS). This approach facilitates the meaningful
introduction of appropriate forms of spatial information and related
technologies for widening public participation in the Policy making process(NCGIA 1996). This participant driven framework should be capable ofrepresenting diverse views without forcing premature resolution ofcontradictions, inconsistencies and disputed as they arise.
Contexts for introducing PPGIS would include community economic
development, environmental dispute resolution, participatory planning, andother activities involving public collaboration. Technologies chosen ordeveloped to support this approach can be designed to document and record
the problem resolution process, allowing evolving priorities and problem
definitions to be tracked by all participants.
Sandman (1993) has identified nine publics relevant to discussion
about community problems. The publics include: neighbors, concerned
citizens, technical experts, media, activists, elected officials, business andindustry, and local, state and federal government regulators (Nyerges andBarndt, 1997).

Internet GIS based Municipal Information System: A Case Study of Dehradun Municipal Area456

99

October 2004, Agra, India

A public participation approach would situate GIS analytical tools
within an expanded framework of communication and discourse, opening
opportunities for public participation across the processes of problem
definition and problem resolution (NCGIA, 1996).
4.0 ADVANTAGES OF INTERNET GIS BASED MIS OVER THE
PRESENT SYSTEM
The advantages of InternetGIS based Municipal Information System(IMIS) are manifold. Some of the most important aspects of it are given
below:
Topologically structuring of GIS database can ensure reduction or
elimination of data redundancy and only one base map for amunicipality. One department develops and maintains the map
while all other use it. This procedure makes it easier to produce
quality map. Also multiple departments can share the cost for thebase map preparation. Time saving is also realized through theinterdepartmental cooperation.
Implementing computerised system can reduce data and time
constraints. Electronic field data record improves not only the fielddata collection process and the efficiency of MIS data acquisition,
but it also boosts the efficiency of the collection of Non-MIS
related data.
Data sharing and workload balancing within the departments canbe achieved through Internet based MIS. Interdepartmental
cooperation can be one of the most prominent advantages. Oncethe initial resistance is overcome participants in the project would
realized the benefits and would eager to share data and workload.
Wide array of data and their cumulative presentation helps the
manager to foresee the demand and supply situation of acommunity in the context of community facilities planning. The
system also facilitate the decision making process by giving
managers more information in a timely manner, thus allowing
administrators to be more informed and quicker in decisions
making.
Continuously changing environment requires frequent updating of
information. It is relatively easier to update information in acomputerised database. Correction and updating of database can bedone easily in topologically structured database without any major
involvement.
Decision-makers need data within a short notice to take thedecision quickly. As a Decision Support System (DSS), an Internet
GIS based municipal information system will provide easy andquick retrieval of information. Maps of selected area / feature andin any scale and size can be produced, in a short notice.

100

New Technologies for Urban Safety of Mega Cities in Asia
457

ICUS Report 6

Figure 1: Conceptual Flow of Internet GIS Software

4.1 Information shown in DMIS
As it is discussed that the aim of this study is to develop an
InternetGIS based MIS for Dehradun Municipal Area (DMIS). Internet
based DMIS has following information with relevant attributes to show andto make query analysis:(a) Base Map(b) Ward Map.
(c) Population Density Map(d) Land use and Land cover Map(e) Slum Map(f) Hydrogeomorphological condition(m)Post Offices(n) Police Stations(o) Parks and Gardens(p) Cinema Halls(q) Training Centres(r) Research Centres and National
Institutes(g) Railway Line and Railway Station (s) Hospitals and Dispensaries(h) Major and Intensive Road Map(t) Religious Places(i) Hotels(u) Waterbodies.
(j) Banks and ATMs(v) Physiography of Study Area.
(k) Schools and Colleges(w)Bus Stands(l) Soil Condition

Internet GIS based Municipal Information System: A Case Study of Dehradun Municipal Area
458

101

October 2004, Agra, India

Figure 2: Interface of InternetGIS based website

Figure 3: Landuse Information on website

5.0 WHY, WHERE AND FOR WHAT INTERNET GIS CAN BE
USED
5.1Internet GIS applications in transportation
Internet GIS provides a perfect tool to access, disseminate andvisualize transportation data. Any information that can be displayed on amap such as highway and transit traffic levels, construction conditions,weather information and so forth can be transferred using Internet GIS. The
US State of California uses “NEVERLOST” – a GIS/GPS application in102

New Technologies for Urban Safety of Mega Cities in Asia
459

ICUS Report 6

their transportation, which gives an exact location of the system anddirections and road maps to the desired location from that point.
5.2 Application sharing
Another approach of server-side Internet GIS is to share GIS
applications among a group of users. Microsoft has created a freeware
software tool that supports collaboration of GIS users over the Internet,
called Microsoft NetMeeting. For instance, while one participant in a
NetMeeting conference launches Arc View or MapInfo to work on a project.
Many people in conference can simultaneously work in the same application.
5.3 Integration of data from multiple sources
Internet GIS provides support for a variety of different data types anda variety of image formats. It can also offer unique and powerful client
integration capabilities, making it possible for users to access the data, thenquickly and simply integrate it with data from many other Intranet and local
sources.
5.4 Highly scalable architecture
Most of the present Internet GIS softwares including ArcIMS are
specifically designed to grow with an organization and to provide acompletely scalable solution for publishing GIS data, maps and its
application. They can be easily scaled to handle the demands of every thingfrom the smallest Intranet to a high volume Internet site.
5.5 Real time information on road conditions and road construction
Real time information on road conditions and road construction withtraffic volume and other related influxes could be studied by Internet GIS
within real and no time.
5.6 Standards based communication
Most of the present Internet GIS softwares provide a goodcommunication between clients and servers using computer languages suchac Arc IMS uses Arc XML (Standard Extensible Markup Language). This
language offers an easy, yet powerful way to customize Arc IMS
application. ArcXML also facilitate transfer and exchange of intelligent
geographic data between different applications.

6.0 GENERAL ANALYSISAs a product of this study an Internet GIS based website is generated.
It is presently providing spatial information related with facilities or points
of interest in following modes at client end:
Location with respect to base map
Zoom in and Zoom out function

Internet GIS based Municipal Information System: A Case Study of Dehradun Municipal Area
460

103

October 2004, Agra, India

Location in terms of X and Y Co-ordinates
Location in terms of their specific names, if any
Finding any specific point of interest by attributes given (Name,
Location etc.)
Query based Finding Approach for any information
Finding any land use of any specific place
Finding any road by name and type of road
Attaining any desired map or needed map
Option of saving of the On-screen map is available.
Option of saving whole project at once is available.
Direct printout of maps is possible.
Option of giving and changing Map Tips.
Option of giving Maps Notes.
Attributes table is accessible and modifications at client end ispossible
Option of Adding Client’s own layers to the site
Option of adding information by other Websites
Facility of measuring any line segment or between two points.
Option of setting scale units of client choice
Creating buffer around any road segment or any Point / Feature
Selection of features, points etc falling within buffer area
Multi-style Selection Possible (By line, point, Rectangle etc.)
Above given options are facilities are available independently andsome functions can be used in harmony of each other also. Almost all the
GIS based functions are available and can be used at client end with ease.
7.0 QUERY BASED ANALYSIS
The main aim behind this study was to provide query-based functions
at client end because these are the functions, which are the real functions
and characteristics of a true Internet GIS based website. In purposed Internet
GIS based website of Dehradun Municipal Area Query function is possible
in three modes:
By Single Entity Selection Approach
By Finding Approach
By Multiple Entities Selection Approach
8.0 RECOMMENDATIONS
As far as recommendations are concerned, it is suggested that –Internet GIS based Municipal Information System can be used as areplacement to paper based information providing system.
Internet GIS based Information Systems should be client oriented
and it should have less technical complexities.

104

New Technologies for Urban Safety of Mega Cities in Asia
461

ICUS Report 6

The authorities handling the paper based information system shouldbe trained so that they can handle Internet GIS based Information
System.
The feedbacks of the clients should be registered properly andweightage should be given to these suggestions wheneverupgradation is executed.
As an experiment, first Internet GIS based Information System canbe used at Municipality Level later it can be used at Tehsil or Taluka
level, if it meets the requirements and expectation.
REFERENCES
George Antonion and Dorthy Deremer, 2001. Computing and Information
Technology. World Scientific, New Jersey.
Robert R. Hoffman and Arthur B. Markman, 2001. Interpreting Satellite
Imagery – Human factors. Lewis Publishers, London.
Environmental Systems Research Institute, Inc., 1997. Using ArcView
Internet Map Server: Map Publishing on the Web. Environmental
Systems Research Institute, Inc. Redlands (California).
Harder, Christia, 1998. Serving Maps on the Internet. Environmental
Systems Research Institute, Inc., Redlands (California).
Huxhold, W. 1991. An Introduction to Urban Geographic Information
Systems. Oxford University Press, New York, USA.
Nyerges T. and Barndt M. 1997. Public Participation Geographic
Information Systems. Proceedings of Auto Carto 13, Seattle, WA.
Van Elzakker P.J.M. 2001. Users of Maps on the Internet. Taylor Francis,
London.
Allan Brown and Menno-Jan Kraak 2001. Web Cartography: Developments
and Prospectus. Taylor & Francis, London.

Internet GIS based Municipal Information System: A Case Study of Dehradun Municipal Area
462

105



PREDICTION OF ATMOSPHERICPOLLUTANT DISPERSION IN AN URBAN
AREA BY WIND TUNNEL EXPERIMENTAND NUMERICAL SIMULATIONRYOZO OOKA, SHINSUKE KATO, HONG HUANG
AND TAKEO TAKAHASHI
Institute of Industrial Science, University of Tokyoooka@iis.u-tokyo.ac.jp
ABSTRACTThe aim of this study is to predict the concentration distribution of air
pollution emitting from the elevated road near the ground level within urban
area, when the atmospheric stability is variable. This study consists of windtunnel experiment and CFD (Computational Fluid Dynamics) analysis. The
equation of plume model, which is used in the simplified condition, isapplied to the prediction of the characteristics of pollutant dispersion within
an urban area, by using data from wind tunnel experiment. This will become
the basis of the accurate prediction method of the concentration distribution
by each hour. In addition, this data are used for validation of CFD analysis.
CFD is conducted using the standard k- model, and will be used for the
real-time prediction of flow and pollutant dispersion in the future.
1.0 INTRODUCTION
The air quality in urban area becomes worse year by year due to theheavy vehicle traffic and the high density of various urban land uses. Manywind tunnel experiments have been conducted to investigate the phenomenaof air pollutant dispersion within the street canyon (e.g. Kennedy and Kent
1977, Wedding 1977, Hoydysh and Dabbert, 1988, 1994). On the other
hand, Computational Fluid Dynamics (CFD) method has become employed
in order to predict air pollutant dispersion in the street canyon recently.
The purpose of this paper is to study the air pollutant dispersion
mechanisms in the street canyons by the wind tunnel experiment and CFD
method and develop the prediction method of dispersion in the street canyon
by comparing the results of the wind tunnel experiment and CFD.
.
2.0 OUTLINE OF EXPERIMENT
2.1 Objectives
The area around a crossing road in the street canyon in IkegamiShinmachi, Kawasaki-city in Japan was analyzed here. This area is famousfor high concentration of NOX from vehicles on the highway and local main
road.

167
463

October 2004, Agra, India
2.2 Model arrangement and measuring techniques
The wind-field and concentration dispersion were simulated in aboundary layer wind tunnel at the Institute of Industrial Science, Universityof Tokyo. The size of the test section of this experimental facility is 1.8m
(H)×2.2m(W) and 14m long. The objective area was modeled partially at ascale of 1:600 (see Figure 1). The diameter of the model was about 1.7m.
Some of hundred buildings and all the streets within the area werereproduced in the model. There is a fence between piers under the highway
in the left hand side from the crossing in Figure 1. For the measurement
concentration, a tracer gas (C2H6) is released from the point source at A ~ E
in Figure 1.


XS

り

Ⅰ交差点
,&URVVLQJ  ＣASRLQWVRXUFH

Ｄ

GQ
り

Ｅ

Ｂ 



高架下に
7KHUHLVDIHQFH
フェンスありXQGHUWKHKLJKZD\  



510m 

1 XS 4 GRZQ 
2 3

Figure 1: Test area for the wind tunnel experiment
3.0 EXPERIMENTAL RESULTS
Experimental results of concentration are shown in the nondimensional value Cn=CUH2/Q. Here C is the dimensional value ofconcentration, H is the height of the highway (=1.33cm in model scale =8m
in real scale), U is the inflow velocity at the height of H and Q is the release
rate of tracer gas(=1cc/s). In this paper, the results under the condition at SE
in wind direction and neutral in atmospheric stability are described.

168

New Technologies for Urban Safety of Mega Cities in Asia
464

ICUS Report 6


3.1 Concentration field
Figure 2 shows the horizontal distribution of gas concentration whengas is released from point A. Gas disperses in the lateral direction along the
highway because the building complex intercepts the stream wise wind. Cn=
0.06 at 35m downward. This means rapid decrease of concentration in thestream wise direction.
N

0.
1

0.
1

1
10

20
30

0
100m



Figure 2 Horizontal Distribution of Concentration
(Wind Direction : SE, Release Point (B1))

Release point

Photograph 1: Visualization of Dispersion(Wind Direction : SE, Release Point(B2))

Prediction of Atmospheric Pollutant Dispersion in an Urban Area by Wind Tunnel Experiment and Numerical Simulation

465

169

October 2004, Agra, India
3.2 Visualization of dispersion
Photograph 1 shows the visualization of dispersion, when the gas isreleased from point B2 under the condition in SE wind directions. Due tothe wake behind the buildings along the highway, the gas flows in the
opposite direction to the stream wise.
4.0 PREDICTION OF CONCENTRATION FIELD WITH WINDTUNNEL EXPERIMENT AND NUMERICAL SIMULATION
4.1 Outline of prediction method with wind tunnel experiment
The Pasquill-Gifford equation is widely used in order to predict
concentration field from a point source. Here, the prediction method from aline source which is applicable for traffic pollutant dispersion is proposed bysuperposing this Pasquill-Gifford equation. The concentration near the
ground at x m distance in the stream wise direction from a point source, Cxy,is expressed as follows assuming normal distribution.
Cxy=Cx0 * exp(- y2/2σy2)(1)

Where, Cxo is the concentration on the stream wise axis (x axis) through a
point source, y is the distance from x axis and is the diffusion width in ydirection.
4.2 Outline of prediction method with CFD simulation
The standard k- model is utilized here for turbulence modeling.
Simple method is used for time integration. As to discreteizing scheme, thefirst order upwind scheme and the second order central difference scheme
are employed for convection term and the other terms respectively.
4.3 Prediction conditions
The NOx distributions at 1.8m high around 9-10 am September 3 areshown in Figure 4. Table 1 shows generation intensity of CO and NOx

Figure 3: Mesh system of whole computational domain
170

New Technologies for Urban Safety of Mega Cities in Asia
466

ICUS Report 6

based on the investigation of traffic volume conducted on September 3 in
2003. The weather condition on the same day is also shown in table 1. For
three dimensional CFD simulation, the analytical domain is discretized into
1,830,000 unstructured meshes (see Figure 3).
Table 1: Generation Intensity of NOx from Highway and Local Main Road
Local Main
Load(g . m-1 . h-1)

Highway(g . m-1. h-1)

NOx

NOX

Wind Velocity (m/s)

7to8 am

28.72

23.33

0.80

Wind
Direction
NNW

8to9 am

32.31

25.51

2.90

SSE

9to10am

35.21

31.83

1.90

SE

September 3
2003

Weather Condition

4.4 Results
Figure 4 shows the horizontal distribution of NOx concentration. The
results of both the wind tunnel experiment and numerical simulation showshigh concentration about 1.1 ppm around the highway and local main roadand low concentration below 0.1 ppm 450m downward (in the north-west
direction) from the highway. In the upward region from the highway, theconcentration of NOx is almost 0 ppm. The comparison between windtunnel experiment and CFD simulation shows fairly good agreement.

N N

clossing

SE(1) Wind Tunnel Experiment(2) Numerical Simulation
Figure 3: Horizontal Distribution of NOx Concentration (ppm)(1.8m high, 9to10am September 3, 2003)

Prediction of Atmospheric Pollutant Dispersion in an Urban Area by Wind Tunnel Experiment and Numerical Simulation

467

171

October 2004, Agra, India
5.0 CONCLUSIONSWind tunnel experiment and three dimensional numerical simulation
are conducted in order to predict pollutant dispersion from highway andlocal main road in an urban area. The results of CFD simulation correspondwell to those of the experiment. Therefore, three dimensional CFD
simulation is expected to be powerful tool for urban design because it can
predict more detailed concentration distribution.
REFERENCES
W.G. Hoydysh and Dabbert W.F. 1988. Kinematics and dispersion
characteristics of flows in asymmetric street canyons. Atmospheric
Environment 22, 2677-2689.
W.G. Hoydysh and Dabbert W.F. 1994. Concentration fields at urban
intersections: fluid modeling studies. Atmospheric Environment 28,
1849-1860.
L.M. Kennedy and Kent J.H. 1977. Wind tunnel modeling of CO dispersal
in city streets. Atmospheric Environment 11, 541-547.
J.B. Wedding, Lonbardi D.J. and Cermak J. E. 1977. A wind tunnel study ofgaseous pollutants in city street canyons. Journal of the Air Pollution
Control Association 27, 557-566.



172

New Technologies for Urban Safety of Mega Cities in Asia
468

AUTOMOBILE TRAFFIC GENERATEDATMOSPHERIC POLLUTION: NEED FORCONSIDERATION IN URBANINFRASTRUCTURE PLANNING
D. MOHAN
Institute of Technology, B.H.U., Varanasi, India.
devmohan9@yahoo.com
ABSTRACT
Megacities in Asia have reached alarming levels of atmosphericpollution due to rapid urbanization, enhanced industrial activities andincreased emissions from automobiles.
Due to severe degradation in air
quality, various types of physiological disorders are being noticed in asignificant proportion of exposed urban population. Consequently, theexpenditure incurred on ‘air pollution induced health hazards’ has been
rising steadily. Automotive traffic also contributes to atmospheric burden ofradiatively important trace gases such as carbon dioxide, methane andnitrous oxide.
Chlorofluorocarbon emission from automobile airconditioners has a deep impact on global climate. Light absorbing propertyof diesel particulate matter affects radiation balance of the planet Earth.
In spite of various efforts to curb the menace of automobile traffic
generated pollution, improvements achieved in the quality of urban
atmospheric environment has remained far from the satisfactory level. In
fact, various physiological threats, which may arise, to human health due tothis source of pollution are not given appropriate weightage at the time ofplanning of surface transportation infrastructures in urban areas. This
paper draws attention towards the importance of this neglected aspect inurban planning. It also emphasizes that there is an urgent need for inclusionof vehicular traffic generated atmospheric pollution as one of theparameters in planning of surface transportation infrastructures inmegacities so that improved level of safety to health of the inhabitants may
be ensured.
1.0 INTRODUCTION
Rapid urbanization coupled with greater demand for transportation for
day-to-day activities have created near chaotic traffic conditions in a numberof cities and towns in many developing countries of the world. According
to certain studies, 50% of the population is expected to live in urban areas in
the beginning of the twenty-first century, making the problem of urban
transport a challenge to city planners and transport operators(Chandrasekhar, 1994). A large body of data has implicated motor vehicles
as a prime contributor to urban air pollution (Ludwig, 1967). Over the years,
there has been a substantial increase in air pollution caused by vehicular
exhaust emissions due to addition of more and more vehicles on roads to

183
469

October 2004, Agra, India

meet the rising transportation demand (Mayer, 1999; Sharma, 1997; Sharmaand Khare, 2001). An economic survey conducted by the Government ofIndia indicated that total number of automotive vehicles (four-wheeler orwith more wheels) manufactured in 2000-2001 was 7, 84,000, out of which
about 6, 32,000 were cars. Six years ago, the figure was about half of it.
The number of two-wheelers manufactured in the same period wasstaggering 3.75 millions. Over the last few years, the growth in the sale oftwo-wheelers in India has been compounding at the rate of over 15% every
year, at times even touching a whooping 20%. About 35% of total numberof two-wheelers are sold in four metropolitan cities (Delhi, Kolkata,
Mumbai and Chennai) and 30 ‘A’ class cities with populations exceeding 5
millions in India (Sivaramakrishnan, 2002).
Atmospheric pollution in large urban areas is still on rise worldwide or
has shown only marginal reductions at some places. The studies carried out
at city of Chile are an appropriate example with respect to various air
pollutants (Jorquera, 2002a and 2002b). According to the findings of
Global Workshop on Air Pollution, large cities in South Asia have reachedalarming levels of air pollution due to rapid urbanization, industrial
activities and increasing emissions from automobiles. The expenditure
incurred on health-related problems has been estimated to be about U.S.
$ 200 millions per annum for Dhaka, the capital city of Bangladesh(Montague, 2000), which has been found to be highly polluted due tovehicular exhaust in a study carried out continuously for four weeks by Pauland Quader (2002). It was found there that an average concentration ofparticles with size less than or equal to 10 m was 422.7 g/m3 in ambient
air, which is much in excess of the permissible limits set by Department ofEnvironment, Bangladesh or United States Environmental Protection
Agency. According to one estimate, the contribution of mobile sources tothe total emissions of hydrocarbons (C2-C9) in Korea has been found to be
more than 70% (Na, Kim and Moon, 2002). Personal exposure to CO infive European cities of Athens, Basle, Helsinki, Milan and Prague wasmonitored for 48-hours and for the period shorter than this. It was observed
to be pronounced particularly in street traffic, where CO concentration inambient air became quite high due to inadequate dispersion (Georgoulis etal., 2002). In a recent study on contribution of automobile emissions to air
pollution conducted in Beijing and Guangzhou, it was observed that thissource contributed more than 80% of CO and 40% of NOx (Fu et al., 2001).
Delhi has been found to be the fourth most polluted city in terms ofconcentration of the suspended particulate matter (SPM) in ambient air(WHO, 1992). Mumbai, the economic capital of India has also been
observed to be the fourth highest NOx polluted city in the world (Srinivas,
1999). Table 1 presents the trend of rise in sectoral share of contribution of
surface transportation to the pollution of atmospheric environment of Delhi
and Table 2 shows estimated quantities of different automotive exhaustpollutants emitted in the atmosphere there.

184

New Technologies for Urban Safety of Mega Cities in Asia
470

ICUS Report 6

Table 1: Trend in sectoral share (%) of air pollution in Delhi(Srinivas, 1999)
SectorIndustry
Transportation
Domestic

1970-71
56
23
21

1980-8140
42
18

1990-91
29
63
8

2000-2001
20
72
8

Table 2: Vehicular pollution load in Delhi (PNL, 1997)
Load (thousand tonnes/ year)
Pollutant
1991
1996
2000
2005
A
B A
B
A
B
A
B
Carbon monoxide 243 - 373
351
477
406
606
441
Hydrocarbons
82 - 123
113
156
135
198
149
Nitrogen oxides
139 - 208
207
261
250
330
279
Sulfur dioxide
10 15
15
18
16
23
18
Lead
0.19 - 0.297 0.259 0.384 0.269 0.489 0.276
Particulate matter
19 28
28
35
34
44
41
A-No control measures, B-With enforcement of emission norms and fuelquality
Uniqueness of gasoline consumption in India is that two- and threewheelers account for about 65% of the total fuel used by all the vehicles.
Besides the vast number of two-wheelers, the technology used in theirproduction also ensures this segment of India’s vehicular population toremain the largest contributor to load of air pollution in Indian megacities(PNL, 1997). Because of this fact, even a small city like Silchar in the stateof Assam in India has been found to have significant level of air pollution
due to automotive traffic and it has been reported that a sizeable portion of
the urban population was suffering from its adverse effects on human health(Pandey and Pandey, 2003a and b). In a number of studies conducted indifferent Indian cities, it is found that the quality of air has deteriorated to aperceptible degree due to pollution originating from mobile sources(Mariappan et al., 2000; Pandey et al., 1998; Pandit, 1974; Prakash andAlappat, 1999; Ramamurthy and Thirumaran, 2002; Sivacoumar, 2000;
Srinivas, 1999).
CO is one of the most abundant of the gaseous pollutants found inautomobile exhaust. It is a colorless, odorless, tasteless but flammable gas,
which is a product of incomplete combustion. It accounts for more than
50% of air pollutants pool in USA and also worldwide. More than 4x1012
kg of CO is emitted globally every year (Li et al., 2000). In megacities, due
to largely obstructed airflow, prolonged periods of stagnation lead toinadequate dispersion and consequently, result in enhancement of ambientconcentration of CO in air. Community CO levels vary with proximity totraffic, traffic volume, type of traffic and many meteorological variables.
As CO emission increases with decreasing engine speed, traffic congestion
enhances ambient CO concentration both by increasing the number of

185

Automobile Traffic generated Atmospheric Pollution471

October 2004, Agra, India

vehicles on given stretch of road and also, by enhancing the value ofemission rate per unit road length travelled by each of the vehicles. COconcentrations in ambient air encountered in heavy traffic is about threetimes higher in comparison to that in commercial areas and five times higher
than the value observed in residential areas. In developed countries,
estimations of CO concentration in and around roadways and urban arterials
are considered essential (at the stage of environmental impact assessment) todesign the layout of different transportation routes (Cooper, 1987; Koushki,
1991; Ward, 1975). Keeping the hazardous nature of CO in view, it has
been used as an indicator of air quality for design and operation of tunnel
ventilation systems also (Chen et al., 2002).
2.0 FACTORS AFFECTING AUTOMOTIVE EXHAUSTRoad transport in India poses typical problems because of mixed
traffic flow having about 13 different incompatible types of vehicles
occupying the same right of way and moving in aggregated flow. Thissituation causes speed of the traffic movement to go down drastically. Thiscondition results in higher consumption of fuel for relatively less distancetravelled and consequently, enhanced quantities of air pollutants are emitted
into the exhaust. In general, numerous short low speed trips accompanied
by frequent starting, idling, acceleration, deceleration and stopping make forvery inefficient and highly polluting automobile operation. In India,
operational cost of a vehicle has been estimated to go up by 20-25% on badroads, in addition to aggravation of the air pollution problem. Due to bad
conditions of roads, the fuel of about Rs. 20 millions is wasted everyday, i.e.,
wastage of about Rs. 7,300 millions every year. In addition, about Rs. 50
millions per day, i.e., approximately Rs. 18,250 millions additional wastage
per year has been estimated to be due to expenditure on vehicle maintenance.
Average mileage is estimated to be 12 to 30 kmpl in Delhi and average
speed on some roads, to be as low as 10 kmph. It has been estimated that by2011, there may be 6 millions vehicles in Delhi in comparison to 1.2 million
cars and 2 millions two-wheelers in the year 2002 (TOI, 2002). These
conditions will lead to further worsening of air quality in Delhi, which gives
an indication about the air pollution scenario, probably going to emerge in alarge number of other Asian megacities.
The exhaust composition depends on many variables like engine type,engine operating conditions, driving mode, type of fuel, vehicle age, makeand maintenance conditions, type of emission control system, weight ofvehicle and its engine capacity and many other engine variables. Many
studies reveal the effects of various operating parameters on exhaustemission from vehicles (Andre et al., 1994; Beaton et al., 1995; Belardini etal., 1993; Bendsten and Thorsen, 1995; Cernuschi et al., 1995; Hansen et al.,
1995; Jensen, 1995). Certain parameters related to operation, maintenanceand driving behaviours can be modified to a large extent by planningappropriately the surface transportation infrastructures in Asian megacities.

186

New Technologies for Urban Safety of Mega Cities in Asia
472

ICUS Report 6

3.0 ENVIRONMENTAL IMPACT OF THE AIR POLLUTION
The health effects of the pollution generated by automotive traffic are
yet to be fully understood, but increasing incidences of asthma, otherrespiratory diseases and certain types of cancer have been linked to various
exhaust pollutants such as carbon monoxide, oxides of nitrogen and volatileorganic compounds (Clifford et al., 1997). One of the studies sponsored byWorld Bank revealed that about 4.0 millions people were afflicted withailments caused due to atmospheric pollution in Delhi. In Kolkata, it has
been estimated to be around 3.5 millions and in Mumbai, about 2.5 millions.
There occurred about 40,000 deaths in India every year, mainly due toadverse physiological effects of air pollution generated by automobiles. In
Delhi alone, air pollution related mortality rose to 7,500 deaths per year as
the city air received more than 2000 tonnes of air pollutants fromautomobile exhaust every day (Bhattacharya, 2001; Pandey, 2001). It isshocking to note that about 40 percent of children in Kolkata were found tobe suffering from respiratory distress syndrome due to air pollution(Bhattacharya, 2001). Average figure of human morbidity and mortality hasrisen to about 57,000 everyday in 36 Indian cities, with about 26 million
people being hospitalized every year, due to different diseases caused byatmospheric pollution (Pattnaik and Pattnaik, 2000). The estimate of cost(due to biospheric pollution) to India in 1995 was Rs. 3, 68,000 millions outof which an amount of about Rs. 52,400 millions was attributed to adverse
health effects of urban air pollution alone (IJEP, 1999). There has beenconclusive evidence that polluted air of Delhi is responsible for over 40% of
the emergency hospital admissions due to breathing or heart problems. The
study found an increase of 41% in asthma cases, 39% in chronic bronchitis
and 30% in heart attack cases. The emergency ward of All India Institute ofMedical Sciences (AIIMS), Delhi has been reported to receive about 150
patients everyday from the geographical area within 10 km of radius (IJEP,
1999). The statistics of prevalent diseases in Delhi in recent past shows that
there has been a steep rise in the number of patients facing various
physiological disorders related to air pollution (Srinivas, 1999).
Automotive emissions not only lead to severe degradation in urban air
quality on micro-scale of meteorology, but are also reported to contribute toatmospheric burden of radiatively important trace gases, which havepotential to influence the global climate significantly (Deluchi et al., 1987;
Unnasch et al., 1989), such as CO2, methane and nitrous oxide.
Chlorofluorocarbon emission from automobile air-conditioners is found tocause greater impact on global climate than CO2 emissions from engines
using gasoline as fuel (Amann, 1990). Light-absorbing property of diesel
particulate matter (DPM) found in exhaust of diesel engines also affects
Earth’s radiation balance. The transportation sector is responsible for about
26% of the green house gases emissions in United States and due toincreasing demand for gasoline and diesel fuels, it has been estimated to be
one of the fastest growing sources of such emissions in near future(Transportation and global climate change, 1998).

187

Automobile Traffic generated Atmospheric Pollution473

October 2004, Agra, India

4.0 TRANSPORTATION INFRASTRUCTURES AND CONTROL OF
POLLUTION
Attempts to control automobile exhaust pollution by adoption ofprimary and secondary measures have not been successful in light of everevolving regulations in connection with concentrations of various pollutantsin the exhaust. Therefore, multi-pronged strategy need be adopted for
effective abatement of pollution due to automobile exhaust to realize thegoal of healthy air environment in Asian megacities. For gasoline powered
vehicles, driving at an optimum speed of 30-40 kmph in case of two/threewheelers and 45-55 kmph in case of four wheelers can be possible only after
ensuring an appropriate planning and operation of surface transportationroutes. This may also help to a large extent in avoiding harsh braking, andfrequent acceleration and deceleration while driving, which are highly
polluting phases. For diesel-powered automobiles, optimum driving speed
should be around 40 kmph. In a study conducted recently in Varanasi city,
it was observed that in the vicinity of certain traffic intersections, average
speed of two-wheelers was about 12 kmph; that of autorickshaws, around 10
kmph and in case of four wheelers, about 8 kmph. Thus, it is clear that atthese speeds, all the automobiles will spew excessively high quantities of
exhaust pollutants.
Efforts to abate automobile exhaust generated air pollution without
improving transport management will not meet significant success. This
type of pollution can be controlled by bringing down the total number ofvehicle-kilometres travelled either by reducing the number of vehicles onroad and/or the kilometres travelled by each vehicle. According to an
estimate, it has been found that if fifty bus passengers travel by twowheelers, the pollution generated would be about 36 times more; if by cars,
it will be 23 times more. The buses in Delhi meet nearly half of the demand
for transport, but account for only about 0.7% of total number in the fleet.
Introducing bus lanes and priority to buses at traffic intersections can cut
down travel time by as much as about 25%. Dedicated bus lanes have been
estimated to enhance the carrying capacity of buses by more than 50%. Bus
corridors can be identified and also a shuttle service along these routes
should be provided. If reliable, comfortable, fast, cheap and easily
accessible public transport can be provided and proper infrastructuraldevelopment is ensured, the number of vehicles on-road will go down
drastically.
To achieve lower emissions of automobile exhaust pollutants byensuring smoother movement of automobile traffic around the least
polluting speeds, efforts to develop and apply more and more sophisticatedtechnologies to attain better control of traffic flow have been going on andconsequently, many concepts like intelligent vehicle highway system(IVHS) etc. have emerged. IVHS uses the latest technologies to squeeze
more transportation from existing capacities of roads, allow the vehicles tomove in a more fuel efficient manner and faster, improve highway safety,
reduce fuel consumption, ease pressure for new highway construction, make188

New Technologies for Urban Safety of Mega Cities in Asia
474

ICUS Report 6

public transportation system more attractive and also help to reduce
quantities of different air pollutants generated by the traffic. Intelligent
transportation system (ITS) technologies, if integrated into surface
transportation infrastructures and vehicles, traffic flow can be monitored andmanaged, congestions can be minimized and alternative routes to travellers
can be indicated. This will cut down the time of travel and also, reduce theair pollution caused by automobile emissions.
Advanced traffic
management system can also be applied to monitor the traffic, optimise
signal timings on major routes and control the flow of traffic. This will help
in mitigation of recurring and non-recurring congestions, leading to
reduction in the air pollution. Highway advisory radios may also be used to
guide the travellers along less congested routes. These may also provide
information about public transit alternatives, traffic conditions along shortsegments of specific routes and parking availability. Such information may
help greatly in bringing down indirectly the quantity of pollutants generated
by automobiles.
5.0 CONCLUSION
The process of urbanization has progressed at a fast pace in Asia also
and so, megacities in this continent have expended rapidly. Consequently,
there has been tremendous rise in number of automobiles to meet theenhanced transportation demand. Due to compulsion of accommodating theincreased number of automobiles in existing capacity of roads, average
speed of traffic movement has gone down drastically. This has resulted in an
alarming rise of air pollution caused by automobile exhaust. Therefore,
surface transportation infrastructures need be planned, keeping in view theseverity of the threat to public health due to the air pollution.
Properly planned and operated surface transportation infrastructures
will help in achieving congestion-free traffic flow along with hindrance-free
driving around the least polluting speeds. This will also result in reductionin the probability of formation of street canyons, which tend to retain
various air pollutants by restricting wind movement etc.. Thus, urban
population will realize improved level of safety to the health andconsequently, a huge expenditure on account of ‘automobile traffic
generated atmospheric pollution induced health hazards’ can be brought
down significantly along with alleviation of human suffering.
REFERENCES
Amann, C. A., 1990. The Passenger Car and the Green House Effect.
Society of Automotive Engineers, Paper No. 902099, Warrendale, PA.
Andre, M., Joumard, R., Hickman, A. J. and Hassel, D., 1994. Actual Car
Use and Operating Conditions as Emission Parameters: Derived Urban
Driving Cycles. The Science of the Total Environment 146/147, 225-233.
Beaton, S. P., Bishop, G. A., Zhang, Y., Asahbaugh, L. L., Lawson, D. R.
and Stedman, D. H., 1995 (19 May). On-Road Vehicle Emissions:
Regulations, Costs and Benefits. Science 2687, 991-993.

189

Automobile Traffic generated Atmospheric Pollution475

October 2004, Agra, India

Belardini, P., Bertoli, C., Giacomo, N. D., Iorio, B., 1993. Combustion and
Pollutant Emissions from Light Duty Diesel Engines: The Influence of
Mixing Process and Transient Operating Conditions. The Science of thetotal Environment 134(1-3), 285-293.
Bendsten, H. and Thorsen, H., 1995. A Survey of the Number of Old
Vehicles on the Roads. The Science of the Total Environment 169(1-3),
113-121.
Bhattacharya, S. K., 2001 (Jan. 13-19). Protection of Environment and theRole of Law. Employment News Weekly, New Delhi, 1-2.
Cernuschi, S., Giugliano, M., Cemin, A. and Giovannini, I., 1995. Modal
Analysis of Vehicle Emission Factor. The Science of the Total
Environment 169(1-3), 175-183.
Chandrashekhar, B. P., 1994. Abstract Proceedings of Seminar on
Technology for a Better Tomorrow, Calcutta, 41-42.
Chen, K. S., Chung, C. Y. and Wang, S. W., 2002 (March). Measurement
and Three-Dimensional Modeling of Airflow and Pollutant dispersion in
an undersea Traffic Tunnel. Journal of Air & Waste Management
Association 52, 349-363.
Clifford, M. J., Clarke, R. and Riffat, S. B., 1997. Local Aspects of
Vehicular Pollution. Atmospheric Environment 31(2), 271-276.
Cooper, D.C., 1987. Indirect Source Impact Analysis: Carbon Monoxide
Modeling. Journal of Air Pollution Control Association 37 (2), 13081313.
Deluchi, M. A., Johnston, R. A. and Sperling, D., 1987. Transportation
Fuels and the Green House Effect. University Wide Energy ResearchGroup, UERG California Energy Studies Report No. UER-182,
University of California, Davis.
Fu, L., Hao, J., He, D. and He, K., 2001 (May). Assessment of Vehicular
Pollution in China. Journal of Air & Waste Management Association 51,
658-668.
Georgoulis, L. B., Hanninen, O., Samoli, E., Katsouyanni, K., Kunzli, N.,
Polanska, L., Bruinen de Bruin, Y., Alm, S. and Jantunen, M., 2002.
Personal Carbon Monoxide Exposure in Five European Cities and Its
Determinants. Atmospheric Environment 36, 963-974.
Hansen, J. Q., Winther, M. and Sorenson, S. C., 1995. The Influence ofDriving Patterns on Petrol Passenger Car Emissions. The Science of
the Total Environment 169(1-3), 129-139.
IJEP, 1999 (June). Indian Journal of Environmental Protection 19(6), 462470.
Jensen, S. S., 1995. Driving Patterns and Emissions from Different Types of
Vehicles on Roads. The Science of the total Environment 169(1-3), 123128.
Jorquera, H., 2002a. Air Quality at Santiago, Chile: A Box ModelingApproach-I: Carbon Monoxide, Nitrogen Oxides and Sulphur Dioxide.
Atmospheric Environment 36, 315-330.

190

New Technologies for Urban Safety of Mega Cities in Asia
476

ICUS Report 6

Jorquera, H., 2002b. Air Quality at Santiago, Chile: A Box ModelingApproach-II: PM2.5, Coarse and PM10 Particulate Matter Fractions.
Atmospheric Environment 36, 331-344.
Koushki, P. A., 1991. Evaluation of Street-Canyon Carbon Monoxide:
Dispersion Simulation Model. Journal of Transportation Engineering(ASCE) 117(4), 444-456.
Li, X., Yang, L., Lei, Y., Wang, J. and Lu, Y., 2000 (Oct.). A Method for
Removal of CO from Exhaust Gas Using Pulsed Corona Discharge.
Journal of Air & Waste Management Association 50, 1734-1738.
Ludwig, J. H., 1967 (Aug.). Progress in Control of Vehicle Emissions.
Journal of Sanitary Engineering Division (ASCE), 73-81.
Mariappan, G., Rajashekhar, R. V. J. and Muthusubramanian, P., 2000.
Estimation of Automobile Source Strength for Some Air Pollutants in
Madurai City. Indian Journal of Environmental Protection 20(8), 561565.
Mayer, H., 1999. Air Pollution in Cities. Atmospheric Environment 33,
4029-4037.
Montague, P., 2000 (July).
Girls are Reaching Puberty Early.
THIMMAKKA’S Resources for Environmental Education 2(1), 5.
Na, K., Kim, Y. P. and Moon, K. C., 2002. Seasonal Variations of the C2C9 Hydrocarbons Concentrations and Compositions Emitted from Motor
Vehicles in a Seoul Tunnel. Atmospheric Environment 36, 1969-1978.
Pandey, D. K., 2001 (Nov. 17-23). Effect of Air Pollution on Health.
Employment News Weekly, New Delhi, 1-2.
Pandey, K. M. and Pandey, A. K., 2003a. Impact on Health of Usage of
Non-Conventional Energy Systems for Controlling Environmental
Pollution: A Case Study of Silchar City. Proceedings of Fourth National
Conference on Thermal Systems (FNCTS-2003), Gupta, S. N. andPrakash, O. (editors), Varanasi, 47-59.
Pandey, K. M. and Pandey, A. K., 2003b. Usage of Non-Conventional
Power Generation for Controlling Environmental Pollution: A Case
Study of Silchar City. Proceedings of Fourth National Conference on
Thermal Systems (FNCTS-2003), Gupta, S. N. and Prakash, O. (editors),
Varanasi, 39-46.
Pandey, V., Kumar, A., Pal, A., Singh, N. and Younus, M., 1998. Status of
Ambient Air Quality in Lucknow City. Indian Journal of Environmental
Protection 19(3), 181-184.
Pandit, V. I., 1974. Automobile Exhaust: Air Pollution and Its Control.
Indian Journal of Environmental Health 16(4), 344-359.
Pattnaik, S. and Pattnaik, M., 2000 (Oct. 7-13). Combating Air Pollution inIndia. Employment News Weekly, New Delhi, 1-2.
Paul, M. K. and Quader, A. K. M. A., 2002. A Study of the Air Pollution of
Dhaka City. Abstract Proceedings of Indian Chemical Engineering
Congress-2002, 54.
PNL, 1997. Pollution Control in Problem Areas. Parivesh News Letter 3(IV), 1-11.

191

Automobile Traffic generated Atmospheric Pollution477

October 2004, Agra, India

Prakash, P. V. S. and Alappat, B. J., 1999. Control Strategies for
Automobile Pollution. Indian Journal of Environmental Protection 19(3),185-192.
Ramamurthy, N. and Thirumaran, M., 2002. Automobile Exhaust Level ofCarbon Monoxide: A Study in Chidambaram Town. Indian Journal ofEnvironmental Health 44(1), 37-40.
Sharma, M., 1997 (Nov.-Dec.). Combating Vehicular Pollution: Options
and Approach. Environmental Pollution Control Journal, 7-10.
Sharma, P. and Khare, M., 2001. Modeling of Vehicular Exhaust-A Review.
Transportation Research D6, 179-198.
Sivacoumar, R., 2000. Vehicular Pollution near Roadways in Chennai City.
Indian Journal of Environmental Protection 20(8), 592-596.
Sivaramakrishnan, K. C., 2002. India’s Urban Environment: Growth of
New Patterns. The Hindu Survey of the Environment, 41-46.
Srinivas, D. S. R. K., 1999. Spatial Patterns of Air Pollution in Delhi.
Indian Journal of Environmental Protection 19(3), 172-180.
TOI, 2002 (Feb. 18). Bad Roads Prove to Be Costly. The Times of India,
New Delhi Edition.
Transportation and Global Climate Change: A Review and Analysis of the
Literature (DOT-T-97-03), 1998. US Department of Transportation,
Office of the Environment and Planning, Washington DC, website:
http://www.fhwa.dot.gov////environment/lit/htm.
Unnasch, S., Moyer, C. B., Lowell, D. D. and Jackson, M. D., 1989.
Comparing the Impact of Different Transportation Fuels on the Green
House Effect. California Energy Commission, Sacramento, CA.
Ward, C. E., 1975. Air Quality Manual Modifications. Transportation
Laboratory, California Department of Transportation, Sacramento,
California.
WHO, 1992. Air Quality in Mega Cities of World. World HealthOrganization Publication.

192

New Technologies for Urban Safety of Mega Cities in Asia
478

ROAD SAFETY AUDIT - CHENNAIK.VENKATESAN AND K.P.SUBRAMANAIN
Division of Urban Systems Development, Anna University, Chennai, India
venkatesankanagaraj@yahoo.co.in
ABSTRACTA traffic accident may be taken as a failure of the road or vehicle ordriver system to perform one or more operations necessary for completing a
trip without damage or injury.Chennai is one of the mega cities in India.
The accident rate of Chennai is increasing every year.Efforts are being
made to study the traffic accident scene in Chennai in order to take suitablemeasures to bring down the accident rate.
1.0 INTRODUCTION
The accident rate of Chennai is increasing every year. So Chennai istaken as a case study for road safety audit. Accident data of 2003 isanalyzed and the road safety measures are given.
Table 1: Trend of accidents in Chennai city during the period 1990 – 2003
Year

Total no. of accidents

1990

5877

1991

5242

1992

5260

1993

5548

1994

4807

1995

5001

1996

5458

1997

5715

1998

5481

1999

4750

2000

5126

2001

5280

2002

3682

2003

4243

Source: Office of the Joint Commissioner of Police, Chennai

193
479

October 2004, Agra, India


2.0 SEVERITY OF ACCIDENTS

6%

13%

37%

44%

Fatal
Grievous Injury
Simple Injury
Non-Injury

Figure 1: Severity of accidents in Chennai city during the year 2003

During 2003 in Chennai city grievous injury accidents constitutes 44% andsimple injury accidents constitutes 37%.Fatal accidents accounts for 13%.
3.0 TYPE OF VEHICLES INVOLVED

Two wheeler
Car/Jeep/Tempo/Taxi
7%

1% 2%

14%

Lorry
32%

2%

OthersThree wheelers

14%

Bus (Corporation)28%

Bus (Private)
Unknown vehicles

Figure 2: Accidents according to type of vehicles during the year 2003

194

New Technologies for Urban Safety of Mega Cities in Asia
480

ICUS Report 6

From figure 2 it is inferred that two wheelrs (32%),Car/Jeep/Tempo/Taxi(28%) are involved in more number of accdients. Lorry and three wheelers
constitute 14 % each.
4.0 CAUSES OF ACCIDENTS
Table 2:

Number of road accidents in Chennai according to cause of
accidents in 2003

Causes

Fatal
531

Grievous
Injury1889

Minor
Injury1546

Non
Injury230

Total
accidents
4196

Fault of drivers
Fault on passenger

3

1

3

0

7

Fault of pedestrian

1

1

2

0

4

Mechanicaldefects
Bad road condition

4

6

6

4

20

1

4

0

0

5

Bad weather

5

3

2

1

11

Total

545

1904

1559

235

4243

Source: Office of Joint Commissioner of Police
From table 2 it is inferred that the fault of drivers is attributed as a major
cause for the accidents.

54%

Over Speed
Bad over taking
Bad left over taking
17%

Rash driving
Bad right over taking

4%

6%

7%

12%

OthersFigure 3: Percentage of accidents according to the type of driver fault
during the year 2003
Over speeding is the major type of driver fault which are causing theaccidents.Bad overtaking,bad left overtaking,,rash driving and bad right

195

Road Safety Audit – Chennai481

October 2004, Agra, Indiaover taking are other faults of driver.Others include apply sudden
brake,careless drive,yellow line violation,followed closely,self fallen etc.

450
400
350
300
250
200
150
100
50
0

Fatal
Grievous Injury
Simple Injury
Non Injury
Total

Ja
n
F e ua r
br y
au
M ry
ar
ch
Ap
r il
M
ay
Ju
ne
Ju
A ly
S e ug
pt us
em t
O ber
c
N o t obv er
D e embc e ermber

No. of accidents

5.0 DISTRIBUTION OF ACCIDENTS

Month



Figure 4: Month wise distribution of different type of vehicles in Chennai
during the year 2003
The figure 4 shows that the number of fatal accidents are more in
October.The grievous injury and simple injury accidents are more in
January and December respectively.In December, the occurrence of non
injury accidents are more. During January, the total number of accidents
occurred in Chennai is high.
700
No. of accidents

600
500

Fatal

400

Grievous Injury

300

Simple Injury

200

Non Injury

100

Total
y
tu
rd
a

Sa

ay
Fr
id

ay
ur
sd

Th

ed

ne

sd

ay

da
y
es
W

Tu

da
M
on

Su

nd
a

y

y

0

Day of Week

Figure 5: Daywise distribution of accidents in Chennai during the year
2003

196

New Technologies for Urban Safety of Mega Cities in Asia
482

ICUS Report 6




800
700
600
500
400
300
200
100
0

Fatal cases
Non-fatal cases

Ni
g

ht

t
ig
h
La

te

M

N

oo
n
re
n

aw

Fo

D

id
da
y
Af
te
rn
oo
n
Ev
en
in
g

Total casesnNo. of accidents

The above figure shows that the fatal accidents are occurred high on
Sunday.The grievous injury and simple injury accidents are occurred more
on Monday and Wednesday respectively.The non injury accidents are more
on Saturday.

Time of Day

Figure 6: Timewise distribution of accidents in Chennai during theyear2003
The above figure indcates that the fatal cases and non-fatal cases are
more in Night and Forenoon period of the day respectively.
6.0 ACCIDENTS ON ARTERIAL ROADS

100 Feet Road

51%

Anna Salai
14%

E.V.R.Salai
T.H.Road

5%

5%

11%

14%

Kamarajar Salai
Other Arterial roads

Figure 7: Percentage of accidents on arterial roads in Chennai during theyear 2003

197

Road Safety Audit – Chennai483

October 2004, Agra, India


The accidents on major arterial roads such as 100 feet road and Anna
Salai constitutes 14% each.
7.0 REMEDIAL MEASURES
Keeping in view the type of risks involved the following elevenissues have been identified as thrust areas:












Road Infrastructure
Vehicle Safety
Safer driver
Safer speed
Safe motorised two wheelers
Safety of children
Safety of pedestrians and cyclists
Better enforcement
Emergency Medical service
Reasearch and HRD for road safety
Institutional and financial mechanism

7.1 Road infrastructure
The road environment is contributing factor in upto 40 percent ofaccidents.Safety by design must be an integral part of road infrastructure
planning and become a key element in land use development to ensure longterm safety benefits for future road users.
7.1.1 Macro level planning
Engineering measures are taken at two levels,viz.macro-level andmicro-level.In case of macro level,problems are tackled in totality atregional,state and national levels and network planning is carried out as toarrive an optimal solution to the problems.Distribution of traffic amongmodes,known as inter-modal distribution should be carried out
scientifically.Coordinated land use and transport planning needs to be given
importance so as to control the demand aspect of the problem.
7.1.2 Road safety audit
Road infrastructure design should compensate for the inadequancies ofroad users and prevent errors of judgement.Safety conscious planning anddesign of roads and network should be encouraged while undertaking new
as well as upgradation and rehabilitation of road schemes through extensive
application of road safety audits.

198

New Technologies for Urban Safety of Mega Cities in Asia
484

ICUS Report 6


7.1.3 Accident black spots
As high percentage of serious accidents take place on arterial
roads,high accident frequency locations on these roads,otherwise known as
accident black spots should be selected from scientific studies,improvement
plans worked out from detailed studies and implemented on priority basis.
7.1.4 Roadside hazards
Roadside hazards in the form of trees,poles,enbankments and otherfixed objects contribute significantly to occupant injuries.Such hazards
should be identified and treatments known to reduce crash severity such as
removal of fixed objects,installation of guard rail and improvement of roadshoulder carried out.
7.1.5 Ribbon development
A most serious phenomenon is the ribbon development andencroachments,specially near the urban fringes,where there is lack of access
control.At such locations the carriageways are eroded and free flow of
traffic is affected resulting in unsafe conditions besides environmental
degradation.
7.2 Vehicle safety
The measures such as additional safety features in vehicle
design,awareness about regular,preventive and periodic maintenance should
be taken.There should be improvement in method,staff and equipment forchecking vehicle fitness.Spot inspection of heavy commercial vehicles
should be done.
7.3 Safer drive
Safety clinics to be organised for driver of transport vehicles involvedin accidents. The standards of driver training schools should be raised andsupervision of functioning of driver training schools should be done.The
method of driver testing should be improved to cover knowledge of safe
driving practices.The licenses should be renewed only after rigorous
tests.Enforcement of control drinking and driving should be done.
7.4 Safer speed
Appropriate speed limits needs to be set at the local level within thecentrally well planned guidelines to select safe speed.Information systemshould be created to guide the drivers in the selection of appropriate
speed.Enforcement has to be intensified to control over speeding.

199

Road Safety Audit – Chennai
485

October 2004, Agra, India


7.5 Safe motorized two wheelers
Safety engineering of motorised two wheelers should be
improved.Wearing of helmets by riders should be made compulsory.Strict
enforcement measures should be taken.
7.6 Safety of children
Training programme for teachers should be conducted and awarenessprogramme for parents is necessary.Road safety should be included in the
curriculum.School safety zones should be provided as model
projects.School children must involve in road safety activities.
7.7 Safety of pedestrians and cyclists
Land use planning should be directed towards encouraging walking
and cycling.Proper infrastructure facilities should be provided for safe andcomfortable movement of pedestrians and cyclists. Enforcement should beenhanced to ensure safety of pedestrians and cyclists.
7.8 Better traffic enforcement
Traffic police force should be strengthened and modernised.Well
planned and targeted enforcement campaigns should be conducted forachieving greater compliance with traffic laws.Penalties should be more
appropriate and proportionate to the seriousness of the offences.
7.9 Emergency medical services
Organized central ambulance services should be there in city.A
network of trauma care facilities should be established in the Chennai
city.Mass campaigns should be organised to highlight the importance of
emergency medical response.
7.10 Research and HRD for safety
The research on priority areas should be encouraged in teaching andresearch institutions.Suitable institutions for training nad research should beestablished.
7.11 Institutional and financial mechanism
The responsibilities of various stakeholders of road safety should be
defined properly.The organisations should be strengthened at appropriate
levels.Adequate funds for implementation should be earmarked.

200

New Technologies for Urban Safety of Mega Cities in Asia
486

ICUS Report 6


8.0 CONCLUSIONS
The accident data of Chennai city for the year 2003 was analysed. The
analysis shows that out of the total number of accidents, grievous injury
accidents constitutes 44% and simple injury accidents constitutes 37%.Two
wheelrs (32%),Car/Jeep/Tempo/Taxi (28%) are involved in more number of
accdients. The fault of drivers is attributed as a major cause for theaccidents in Chennai city during 2003. Over speeding is the major type ofdriver fault which caused the accidents. The accidents on major arterial
roads such as 100 feet road and Anna Salai constitute 14% each.
Based on the analysis road safety audit is done for the Chennai city
basedon the elevenissues such as Road Infrastructure,Vehicle
Safety,Safer driver,Safer speed,Safe motorised two wheelers,Safety ofchildren,Safety of pedestrians and cyclists,Better enforcement,Emergency
Medical service,Reasearch and HRD for road safety and Institutional andfinancial mechanism. The strategy should be evaluated three years andupdated depending on the performance, the then prevailing conditions andneeds.
REFERENCES
Agarwal ,R.C.,1997. Road accidents in India – Causes and remedial
measures. Indian Highways Journal.
Deshpande,M.D.,1998. Study of accidents on N.H.No:8 of Ahmedabad
Ajmer section from Kms 388/4 to 481/4. Indian Highways Journal.
Srinivasan,N.S., 1987. Scientific identification and improvement of accident
prone locations on N.H.No:47 in Kerala.Indian Road Congress Journal.
2003. .Studies undertaken to identify critical causes of accidents in the
Highways of Tamilnadu. Indian Highways Journal.

201

Road Safety Audit – Chennai
487

2D - EA FOR FACILITY ALLOCATIONRAJIV GUPTA
Birla Institute Of Technology And Science, Pilani, India.
rajiv@bits-pilani.ac.in
ABSTRACTIn a world that is rapidly shrinking and where land is at a premium,proper use of land is of utmost importance. This demands that we allocate
space to our facilities (residential buildings, commercial houses,
recreational and entertainment centers, etc.) effectively. Genetic Algorithms
have been used extensively for planning purposes. However, traditional
approaches emphasized on the vector or one-dimensional approach.
A new algorithm for designing the layout of facilities is presented inthis paper. The algorithm uses a 2 - dimensional genetic algorithm (GA),called 2-D Evolution algorithm (2D - EA), which employs GA common
operators in 2-dimensional form. The present work makes use ofgeographical information system software to convert the image/ digital map
in two-dimensional matrix that is used as chromosome to apply genetic
algorithm. This work deals with the design and implementation of 2D - EA
for optimal layout of facilities. Given a set of facilities and the site in which
they are to be placed and the distance between each of the facility, thealgorithm proposes solutions, which satisfies the distance constraints
among the facilities. The algorithm generates an initial population and thencalculates the fitness of the individuals of the population and by process of
selection and crossover. It generates the next generation of individuals.
Various functions which generates the initial population, calculate fitness
and perform genetic operations have been implemented using MATLAB.
This form is more suitable as compared to vector form of chromosomes dueto the nature of the problem that is related to space allocation. Since 2D EA can be applied directly on the remote sensed images/ scanned maps, theneed for compression and possibility of 'dimension crunch' does not arise.
The method is demonstrated on a real life problem of campus facilities
allotment. The paper concludes with the strength and limitations ofproposed algorithm.
1.0 INTRODUCTION
Urban planning involves many functions (general administration,
development control, plan making, and strategic planning), scales (whole
city, sub-region of a city, a district, a street block, etc.), sectors (land use,transport, housing, land development, environment, etc.) and stages(determination of planning objectives; analysis of existing situations;modeling and projection; development of planning options; selection ofplanning options; plan implementation; and plan evaluation, monitoring,and feedback). Plan making and non-routine strategic planning are

203
488

October 2004, Agra, India

undertaken much less frequently as compared to General administration anddevelopment control (Yeh 1999).
The layout problem is one of the important problems in the planningof service facilities since efficient layout is critical to cost-effective
operation of the facilities (Karray et al. 2000). Good facility layout isimportant to promote safe, efficient, and optimized operations concernedwith day-to-days life. Therefore, in the design process of the layout, many
objectives are considered (Francis and White 1974; Tompkins et al. 1984).
Traditionally, planning a layout is an iterative process till a compromise isreached (Whitehead and Eldars 1965). These trials and error are carried out
on maps (2 - D sheet) or now days some computing efficient techniques like
Genetic algorithms (Holland 1962) are used. A large amount of work has
been reported in the literature to deal with the layout problems. The methods
mainly used are Heuristic, Computer-based systems, Artificial Intelligence/
Expert Systems, Artificial Neural Network, Fuzzy Set Theory, Geographical
Information system (GIS), and Genetic algorithm (Zouein et al. 2002).
The main weaknesses of the existing methods are their linkage withurban planning model. The present work suggests a model based on EA thatcan be used as the substitute of this linkage or enhance the efficiency oflinkage GIS with planning model. The present work makes use of GIS toconvert the images in two-dimensional matrix that are used as chromosomes
to apply GA.
1.1 Genetic algorithm
These algorithms perform random searches through a domain of
possible solutions, with the aim of finding the best alternative with respect
to a given definition of 'goodness'. This goodness is expressed as 'fitness
function', a function that evaluates the given solution over the given criteria.
The search is performed over a finite set of alternatives. The alternatives orsolutions are coded traditionally as a one-dimensional vector, which arecalled 'chromosomes'. A set of chromosomes is known as a 'gene pool'. The
algorithm, in its simplest form can be expressed as:







204

Randomly create an initial pool of alternatives (chromosomes).
Given the 'fitness function', each member of the gene pool isevaluated in terms of this fitness.
The next generation is selected from the gene pool, by skewing therandom selection process in favor of the fitter chromosomes, called'Natural Selection'.
The gene pool is modified by performing certain genetics
operations, like crossover and mutation and some other special
operations like inversion, etc.
The new population replaces the initial population.
This process is repeated till the stopping criterion is satisfied.

New Technologies for Urban Safety of Mega Cities in Asia
489

ICUS Report 6

The proposed EA is a modified form of the generic genetic algorithm.
The basic functions of Selection, Crossover, and Extinction are modified.
The basic consideration in developing this evolutionary algorithm is to adapt
the vector based GA approach to two-dimensional maps/ satellite images.
The conversion of images in one-dimensional form leads to a loss of spatial
information, and thus could not be used satisfactorily. Here, the attempt is to
use the evolutionary approach directly on two-dimensional images.
The basic aim is to get an optimum facility layout such that theproximity among related facilities is as desired. The algorithm can beapplied either to optimize the facilities locations in given area or to modify
the locations of existing facilities in an area.
2.0 TWO-DIMENSIONAL EVOLUTIONARY ALGORITHM (2D EA)
The basic steps, which are further described in details, involved in the
proposed 2D - EA are as follows:









Calculation of base values (area, number, and distances) for theoriginal map and for each facility. Here the unit area for a facility
is kept constant; and to satisfy the need, number of unit area for thefacility is changed.
Generating a parent pool of two-dimensional matrices, which
satisfy the given constraints.
Calculation of the fitness value for each matrix.
Generating the gene (child) pool through 'Natural Selection'
process.
Creation of new matrices through the process of altered crossover.
Calculation of the fitness value for the child matrix, based on
which it is decided whether the matrix to join the child pool or
become extinct.
Repetition of steps 5 to 7, till the specified number of iterations is
over.

2.1 Calculation of base values
Base values are the parameters like unit area and number for eachfacility. These base values for the parameters are created from the map/
images as follows:Starting from a processed existing map, the prohibited places(facilities can not be placed due to various reasons) are marked.
Reading in the processed image into a matrix variable.
Reading in the processed image for the unit areas into a matrix
variable.
Deciding on a priority for placing each facility. The facilities
which occupy maximum space are placed first. Priority is given to

2D - EA for Facility Allocation

205
490

October 2004, Agra, Indiafacilities with larger unit areas, and then to facilities with larger
total areas but small units.
Calculating the total area for each facility and the unit area maps.
This is done by summing the number of elements in the matrix
corresponding to the gray level intensity for the particular facility.
Dividing the areas in the matrix by the areas in the unit area matrix
to get the total number of each facility.

Once the base values are obtained, the next step involves thecalculation of the parameters for the generated matrices. The following
assumptions have been made to calculate the facilities parameters for thegenerated matrices:The total area available for construction remains constant.
The area of the unit facility remains same.
Number of each facility units required is known.
The increase in facility area is manifested as an increase in facility
units.

To optimize the facilities locations in given area, unit area and the total
numbers of each unit are decided by the user according to the need. Placingthese facilities in random fashion creates a base map, and then algorithm isapplied.
2.2 Generation of parent pool
The first step involved in a map creation is to define the areas where
facilities cannot be placed. According to the facility priority decided on, arandom number is generated for the X and Y coordinates to place thefacility unit in the range of map. The area occupied by the prospective
facility unit is checked for the presence of any other facility. If the condition
is met, place the facility unit by making the values of the elements in thematrix equal to the facility unit number. This process is repeated for all
facilities. The numbers stored are in continuous forms, i.e. for 9 facilities
with 5 units each, the numbers stored range from 1 to 45. Thus, a separate
identification number distinguishes each facility unit placed. The range offacility unit numbers for a particular facility type is stored. The starting
point of each facility placed is stored in a separate matrix; this then acts as areference matrix. This is used to carry out 1-dimensional operations likedistance calculations. If it becomes impossible to place a particular facility
unit after a specified number of times, then start afresh with a new blankmatrix. The process is repeated till the parent population is complete.
2.3 The fitness function
Each chromosome (in the usual GA) or matrix (2D - EA) denotes aparticular solution. The higher the fitness value, the better is the solution.
Here, proximity is chosen as objective function. Proximity is the shortest
edge distance between two entities. In planning of smaller places, proximity

206

New Technologies for Urban Safety of Mega Cities in Asia
491

ICUS Report 6

is better indicative of spatial closeness between two entities than center-tocenter distance. A facility unit, in case of rectangular shape, is represented
by the upper left (X1, Y1) and lower right (X2, Y2) coordinates. Here, theproximity between facility unit i and facility unit j is expressed as:jj
Min ( (X i  X m ) 2  (Y i  Ym ) 2 ); l  1, 2; m  1, 2
l
l

(1)

The total proximity for n facility units is:
j 2
j 2
i
i

 Min (Xl  X m )  (Yl  Ym ) ); l  1, 2; m  1, 2
i  1:n j  1:n(2)

However, the approach described above is not capable of expressing
extra spatial relationships. For example, the proximity between a residential
area and a shopping complex could be preferably high. The problem isovercome by introducing a Proximity Matrix (Pnxn: symmetric matrix) for 'n'facilities, which gives relative weights on the proximity between two
facilities. Thus, the ith row and the jth column will indicate how close the ith
facility should be to the jth facility. The diagonal elements indicate how
close the unit areas of the same facility should be to one another. To
calculate the diagonal element in the ith row and ith column, the weight (Wi,i)
attached is:

Total number of units of facility iW i,i Total number of facilities units in the area

(3)

With this as the diagonal elements, the other weights are given inproportion to this. Hence, the fitness function now becomes:
1
j 2
j 2
i
i
 (  Min ( (X l  X m )  (Yl  Ym ) ) * Wi', j'i  1:n j1:n; l  1, 2; m  1, 2 (4)Here Wi', j' is the weight between the i' and j' facilities, with the ith unitof i’ facility and the jth unit of a j' facility. This fitness function needs to be
maximized for the optimum result. In the proposed method, Natural
selection and Crossover functions of prototypal genetic algorithm aremodified.
2.4 Natural selection

Given a percentage for crossover, the remaining chromosomes(matrices) are generated using natural selection. Thus, for a crossover
percentage of 0.4 and population size 100, 60 chromosomes are passed
directly to the next generation. The fitness function of each matrix is
calculated, which is divided by the sum of fitness to give the relative fitness
for each matrix. The values of the relative fitness are summed up in a

2D - EA for Facility Allocation

207
492

October 2004, Agra, India

stepwise manner, thus yielding a set of continuous intervals, which arelarger for matrices with higher fitness. A random number is generated, andchecked with the fitness intervals. For the range it falls in, the matrix withthe upper bound fitness value is chosen. This process is repeated till therequired number of chromosomes is selected.
2.5 Crossover
Crossover for 2-D matrices is a rather complicated concept. The
regular crossover operation proves to be inefficient in this case. A new
crossover mechanism is suggested in this study, which can be viewed as a
combination of crossover and random generation. The steps involved are as
follows:







Store the boundary coordinates for each unit of the facility.
The modified crossover starts with the selection of two parents
from the pool. The selection is done using the natural selection
operation.
The child matrix will contain each facility on location either fromthe corresponding facility location in parent 1, or parent 2. The
number is randomly generated (either 1 or 2) for each facility unit.
If the facility cannot be placed according to one parent in the given
row and column then try to place it by interchanging the row andthe column otherwise try to place it according to other parent. Ifneither option is possible, then it is randomly placed. As thepercentage of random placements to total facilities becomes morethan 0.4, the child is discarded and the crossover is repeated.
The fitness of the child matrix is calculated.
4

2

1

4

2
1

2

1

4
3

3

3

Chromosome 1+

Chromosome 2  Child Chromosome

Figure1: Modified crossover operation
In this study, a biased random method with respect to the worst fit caseof the previous generation is selected to decide on the survival of child
chromosome. The user provides a value for the rate of survival. If the matrix
generated has fitness less than the least fit of the previous generation, then arandom number is generated. If this number is within the survival rate then208

New Technologies for Urban Safety of Mega Cities in Asia
493

ICUS Report 6

the chromosome is allowed to enter the pool or else it is exterminated, andthe process is repeated to generate another child matrix.
Using the modified crossover operation, required child matrices are
generated. To remove the duplicity, the child chromosome is evaluated andits fitness is compared to the least fit matrix of the previous generation. As
per the survival rate, either it joins the population or exterminated. Here too
the reference matrix containing the starting points of each facility unit isstored. Finally the fitness is calculated for this generation, and the reference
matrix updated. This serves as the parent pool for the next generation, andthe process is repeated. For the present study, the mutation operation is notincluded.
2.6 Evaluation of matrices
Once the parent pool has been created, use the fitness function to get
the fitness value for each matrix. Use the reference matrix stored for eachchromosome to directly calculate the total weighted-proximity for the wholematrix.
3.0 CASE STUDY
As a case study, the institute campus of Birla Institute of Technology
and Science (BITS), Pilani, India is considered (Figure 2).
The campus map obtained for the project was a binary (Blue andWhite) top view map with proportionate real distances on the ground.
Certain modifications were made to the map to use it for analysis. Thesechanges include: Scaling and Resampling of map, Enhancement of scanned
image of map, Image classification into separate facility or land-use zones,
Conversion of colored map to gray level image (Figure 2), and Conversion
map into a two dimensional matrix.
These changes can be achieved using various software platforms. To
decide on the total number of facilities, nine facility zones (priority wise)
were created: Institute Building, Hostel (boys), Hostel (girls), Staff Quarters,
Shopping areas, Telephones exchange, Information Processing Center,Banks, and Miscellaneous.
The second step was to decide on a unit area for each facility. This was
decided based on the smallest possible unit that served as a center for thatfacility. For example, one hostel was considered as a unit. Using the simple'Cut-Paste' option the areas with a particular facility was filled withrectangles of a particular color equal in size to the unit size of the facility.
Each facility was coded with a different color (Figure 3).

2D - EA for Facility Allocation

209
494

October 2004, Agra, India

Figure 2: Base map of BITS
campusFigure 3: Map after scaling,
reclassification, and grayleveling

The colors used were shades of gray. The area where construction was
not allowed was filled with black, and the free areas were left white. The
unit areas were stored in a separate image, which can be used as a reference
file, later.

Figure 4: Output map after implementation of 2D - EA algorithm
3.1 Conversion to a two dimensional matrix
The image thus obtained is read and stored as a 3-dimensional matrix,
with the elements in each containing the intensity values for R, G and B
layers. For gray level images all these three elements are identical. The Red
layer is chosen as a representative, and used for further processing. The
original and transformed images are shown in Figure.2 and Figure.3
respectively. Once the gray level image has been read in as a twodimensional matrix various operations of evolutionary algorithms can be
performed on it as it can be treated as an ordinary matrix.
4.0 RESULTS
The 2D - EA was developed using MATLAB (MATLAB 1998). The
results were stored as the fitness for successive generations. An example of210

New Technologies for Urban Safety of Mega Cities in Asia
495

ICUS Report 6

a sample output map is shown in Figure. 4. The dark blue/black areas
indicate the 'no-facility’ zones. The output is one of the maps generated after
the 2D - EA was implemented. The computation time depends on Size ofthe image, Number of facility units, Number of iterations specified, andCrossover percentage.

Fitness value 

The program was run many times to come up with suitable values forthe number of iterations, crossover percentage, and extinction rate. In mostof the cases the best results were obtained for crossover percentage less than
50% and close to 40%. The extinction rate was around 99% (implying that
1% of the unfit child vectors would survive without extinction). The output
for crossover percentage of 0.45, 150 matrices, and 150 iterations is shownin Figure. 5.

Number of matrix (chromosomes) Figure 5: Output for crossover percentage 0.45, population’s size
150, and 150 iterations.
The graph shown above is for the starting and ending generations. It isclearly visible that the fitness becomes progressively better at the end of theiterations. For the results to converge, it is seen that larger population sizes
with large number of iterations should be used. However, in such cases
computation time is quite large. Computation time is reduced by increasing
the number of iterations, and decreasing the population size and coefficientof crossover. This aspect needs further study, and experimentation.
5.0 CONCLUSIONSThe project is an attempt to adapt a traditionally one-dimensional
concept to a two-dimensional environment. The results obtained areencouraging. It is observed that two-dimensional approach is more viable
than the vector based genetic algorithms followed till now. One of theimportant application areas that the 2D - EA can be applied is on remotesensed images. Since the 2D - EA can be used directly, the need forcompression and possibility of 'dimension crunch' (loss of information
suffered when converting images to vectors) does not arise. Anotheradvantage of the method is in process a number of feasible configurations offacilities locations are created that can be used for planning anddevelopment purposes. The method is applied with facilities of rectangular

2D - EA for Facility Allocation

211
496

October 2004, Agra, India

shape. However, it can be applied to the facilities of any shape. The
algorithm can be used to incorporate the new facility in existing system or toextend the facilities in near future. The technique is new and needs further
study and analysis; this is a step in the paradigm shift from one to two andperhaps three dimensions.
REFERENCES
Francis, R.L., and White, J.A. 1974. Facility Layout and Location.
Englewood Cliffs, NJ: Prentice-Hall.
Holland, J.H. 1962. Outline for a logical theory of adaptive systems. J.
Assoc. Comput. Mach., vol. 3, pp. 297-314.
Karray, F., Zaneldin, E., Hegazy, T, Shabeeb, A.H.M., and Elbeltagi, E.
2000. Tools of Soft Computing as Applied to the Problem of Facilities
Layout Planning. IEEE Trans. Fuzzy Syst. vol. 8, no. 4, pp. 367-379.
MATLAB User's Manual, Version 5.2 1998.The MathWorks, Inc., Natick,MA.
Tompkins, J.A., and White, J.A. 1984. Facilities Planning. New York:
Wiley.
Whitehead, B, and Eldars, M.Z. 1965. The planning of single-storey layouts.
In Building Sciences. New York: Pergamon, vol. 1, pp. 127-139.
Yeh A G-O 1999. Urban Planning and GIS. In Longley P, Goodchild M,
Maguire D, and Rhind D eds Geographical Information Systems:
Management Issues and Applications’. John Wiley & Sons, Inc, USA.
Zouein, P.P, and Tommelien, I.D. 1999. Dynamic layout planning using a
hybrid incremental solution method. J. Construct. Engrg. Mngmt. ASCE,
vol. 119, no. 2, pp. 266-287.

212

New Technologies for Urban Safety of Mega Cities in Asia
497

PEDESTRIAN SPEED-FLOW MODEL ON
ESCALATORS AND STAIRCASESFOONG KOK WAI AND CHIN HOONG CHOR
National University of Singapore, Singapore
cvefkw@nus.edu.sg

ABSTRACT
Pedestrian flows in underground rail stations are usually heavy
during the peak hours and could result in serious congestion, especially if
the escalators, staircases and walkways, are not adequately built to cater tosuch a demand. During an emergency, it would also be safety hazard to thepassengers. Maintenance of good speed and flow conditions in the station isessential to coping with emergencies.
This study was conducted to examine pedestrian flow characteristics
at underground railway stations in Singapore. Video recordings ofpedestrian movements were carried out in Somerset Mass Rapid Transit(MRT) Station in Singapore to collect volumetric flow data of pedestrians
on staircases and escalators and their travel times on these facilities. The
collected data is then used to calibrate speed-flow relationships for these
two facilities. The study shows that the walking speeds at capacity were 23.0
m/min on the staircase and 2.8 m/min on the escalator approach. In
addition, the parameters and forms of the relationships differ for working
persons, shoppers and the elderly.
1.0 INTRODUCTION
Escalators and staircases are two of the main pedestrian facilities in anunderground railway station, and should be well designed to ensure efficientand safe movement of pedestrians. Although these facilities are provided in
Singapore’s Mass Rapid Transit (MRT) stations, most of them were
designed with referenced to non-local, or out-dated standards. No relevant
studies have been conducted on the characteristics of pedestrians on thesefacilities either prior to, or after the commencement of the rail operation in
1987. Knowledge of the characteristics of pedestrian movements within the
MRT stations could help in optimizing space use and result in more efficientand safer designs for pedestrians. Furthermore, with the recent security
concerns relating to underground stations, there is an urgent need toevaluate the performance of these stations in times of emergencies.
Maintaining an acceptable level of service within the stations during suchoccurrences would be critical in ensuring safe and efficient evacuation.
These two issues have brought about the need to examine the characteristics
of pedestrians along walking facilities in underground stations.
In an urban underground railway system characterized by large
passenger flows and short train intervals, it is important to accommodate theexpected demand so as to ensure the efficient operations of the system.

213
498

October 2004, Agra, India


Fruin (1971) had highlighted a number of problems of using design"standards" in an ad hoc manner, such as using maximum pedestriancapacity, or stated operating capacity of an escalator, as a basis for design.
The dense crowding of pedestrians, who need to resort to restricted anduncomfortable locomotion, is a typical result of a lack of understanding of
the speed-flow relationships and space requirements of pedestrians. A betterknowledge of the relationships can be useful to those involved in the designand operation of pedestrian facilities.
This study examines the relationships between speed and flow ofsingle-directional pedestrian movements, which are the main type of flows
in times of an evacuation from an underground station. The work involved
includes the collection of pedestrian flow and travel time data on escalatorsand staircases in an underground MRT station in Singapore, followed bydata analysis and model estimation. A number of mathematical relationships
have been examined and tested for representation of such flow
characteristics.
2.0 DATA COLLECTION
Among the 65 operational MRT stations in Singapore, Somerset MRT
station is one where the staircase in the station is relatively more utilized.
This is because at this station, the staircase is the nearest facility from theentry gates connecting the concourse to the platform level. Furthermore, it
observed that there is negligible pedestrian upward flow along the staircase,since the escalator in the upward direction is located just beside the staircase.
The near single-directional flow on the staircase therefore coincides with theobjective and scope of the study. The station, which is in the heart ofOrchard shopping area, serves mostly working persons, shoppers andtourists.
A survey was carried out in 28 May 2003 during the evening peakhour and pedestrian data were collected on one escalator and one staircase at
the station using two video cameras. Information on passenger flow,
passenger travel time and the physical dimensions of the facilities werecollected at the site. The travel time measurements included queuing time at
the approaches as well as the time to travel on the facility, since thecongestion at the approach to the escalator and staircase contributes
significantly to the delay in travel time. A survey plan for data collection
and the location of the cameras at Somerset MRT station is illustrated in
Figure 1. Total sample sizes of 676 and 326 pedestrians were collected on
the selected staircase and escalator respectively.

214

New Technologies for Urban Safety of Mega Cities in Asia
499

ICUS Report 6


Figure 1: Survey plan of data collection at Somerset station
3.0 SURVEY RESULTS
3.1 Observed flow capacity
From the video recordings, pedestrian flow and travel times totraverse the entire staircase or escalator were measured. The flows were
measured by counting the number of pedestrian passing the exit of the
facility within a 30-second interval. The capacity flow rate, which isassumed to take the value of the maximum flow rate obtained, is shown in
Table 1. The travel times at each interval is calculated as the average of allpedestrians passing at that interval. In addition, the operating speed of theescalator is 45 m/min.
Table 1: Dimensions and flow characteristics of facilities.
Units
Effective width
Inclined length
Approach length
No. of observations
Average speed
Observed flow capacity

m
m
m
m/min
/m/minPedestrian Facilities
Staircase down) Escalators (up)
1.00
1.00
8.8
12.0
2.0
2.0
676
326
30.4
46.4
45.8
125.0

3.2 Walking speeds
It was found that the mean speed for descending pedestrians on thestaircase was 30.4 m/min. The males generally walked faster than thefemales on the staircase as their mean walking speeds were 31.3 andPedestrian Speed-Flow Model on Escalators and Staircases
500

215

October 2004, Agra, India
29.3m/min respectively. The differences in walking speeds between thesexes were similarly observed by Tanaboriboon, et. al. (1986) and Lam, et.
al. (1995). In addition, shoppers and the elderly and were found to havemuch lower walking speeds of 19.9 and 21.1 m/min respectively.
4.0 SPEED-FLOW RELATIONSHIPS
A variety of mathematical relationships were examined to describe therelationships among speed, flow and density of the pedestrian data collected
at the station. These functions includes speed-flow-density relationships thathave been established for pedestrian flow (Virkler and Elayadath, 1994), as
well as capacity-restraint travel-time functions that have been used
extensively in vehicular flow, transport modeling and planning purposes.
4.1 Flow-speed functions
Four speed-density functions, namely Greenshields’ linear,
Underwood’s transposed exponential, Greenberg’s modified exponential
and May’s bell-shaped curve, are tested against the pedestrian data.
Recognizing that flow can be derived by multiplying speed with density, thecorresponding flow-speed relationships for each of these functions can bederived:Greenshields:

V = S + S 2

Underwood:V =  S – (S ln S)

Greenberg:

V = S exp(- S)

May:

V2 =  S2 ln(/S)

where V = pedestrian flow (ped/m/min), S = pedestrian speed (m/min)
4.2 Capacity-restraint functions
Capacity-restraint techniques are based on the observation that as theflow on a facility increases, the speed decreases; and when the flow
approaches the capacity of the facility, the rate of reduction in speed
increases. They attempt to balance the volume on the facility, the capacityof a facility, and the related speed. There are flow-dependent travel timefunctions that utilize capacity-restraints, and have been applied in vehiculartrip assignment for the prediction of travel times on road networks.
Staircases have similar characteristics as road networks in that theirservice levels are limited by some capacity-related restraints. For example,
the capacity of a staircase is generally governed by its width, and thecapacity of the escalator approach is influenced by the speed of the escalator
and the boarding times of the pedestrians. It would thus appropriate to216

New Technologies for Urban Safety of Mega Cities in Asia
501

ICUS Report 6
employ capacity-restraint functions to describe the relationship between
speed and flow for pedestrian movement.
Several speed-flow curves based on capacity-restraint have been used
for the prediction of travel times on road networks. Some of the most used
includes the functions by Overgaard (1967), Davidson (1966) and the
Bureau of Public Roads, or BPR (1964):
Overgaard:t(V) = t0 exp[( V / C )]Davidson:t(V) = t0 [ 1 +  v /( C-V)]

BPR:

t(V) = t0 + ( V / C )nwhere t = travel time (min) at flow V; t0 = free-flow travel time (min); V =pedestrian flow (passenger/m/min); C = capacity of pedestrian facility(passenger/m/min); while and n are parameters to be estimated.
The BPR function, which is probably the most widely used in
vehicular flow analysis, was also employed by SATURN assignment modelfor the London Underground Station Congestion Model (Daly, et. al., 1991),
and also by Lam and Cheung (2000) in a study of pedestrian flows in Hong
Kong Mass Transit Railway (MTR) stations.
These travel time functions could be converted to speed-flow
relationships simply by using the following equation:
S = l/ twhere S = pedestrian speed (m/min); l = inclined length of facility (m).
The seven speed-flow functions described above would be tested
against the pedestrian data on the staircase and escalator collected in the
study. It is recognized that the speed at which a pedestrian moves along theescalator is generally constant. Thus for the case of the escalator, thewalking speed at the approach of the escalator, denoted by SA in this paper,
would instead be modelled using the speed-flow functions.
5.0 MODEL RESULTS
Linear regression was used to calibrate the speed-flow models against
the collected data. Nonlinear functions were reduced to linear forms, andfunctions with more than 2 parameters were estimated using sequential
programming techniques. The regression results for the functions developedfor each facility are discussed in turn.

Pedestrian Speed-Flow Model on Escalators and Staircases
502

217

October 2004, Agra, India


5.1 Staircase
The results for the calibration parameters of the speed-flow functions
for staircase in the downwards direction are displayed in Table 2. The fielddata are shown against the fitted flow models in Figure 2. All seven models
satisfied the tests for significance of the regression at 95% level. The
coefficient of determination, or R2, for the models ranged from 0.28 to 0.54,
with the Greenberg model exhibit the highest explanatory power. Using thecalibrated Greenberg model, the free flow descending speed on the staircase
would be 79.9 m/min, and the speed at capacity is 23.0 m/min.
Table 2: Speed-flow functions of staircases in Somerset MRT station
Regression parameters
Model

EquationR2

Se

p-value(F-statistic)

Flow-speed functions
Greenshields V = 3.33S + 0.0929S 2
Underwood V = 10.4S – 2.92 (S ln S)
Greenberg
V = 260 S exp(-0.21 S)
May
V2 = 4.23 S 2 ln(32.5 / S)

0.47
0.50
0.54
0.31

3.20
0.0978
2.99
0.110

<0.01
<0.01
<0.01
<0.01

Capacity-restraint functions
Overgaard
S = 35.7 exp (-0.539 V/C)DavidsonS = 32.4[1 + 0.162 v /( C-V)] -1
BPR
S = 8.80[0.174+ 0.191(V/C)0.37]-1

0.37
0.28
0.39

0.110 <0.01
0.0329 <0.01
0.0303 <0.01

It is noted that the values of the parameters obtained explained only
the variability of the data collected in the survey. The parameters for thesefunctions are dependent on factors such as types of pedestrian, time of day,and the design of the staircase. Pedestrians have different trip purposes andthe difference would influence how and the speed at which they walk.
To investigate the influence of types of pedestrian on the forms andparameters of the speed-flow function, 3 pedestrian types were identified
from the video data. Pedestrians rushing down on the crowded staircase andovertaking slower pedestrians were classified as Type I pedestrians. Type II
pedestrians were identified as those who carried heavy bags with them, andthose who appeared to be over 60 years old were classified as Type III
pedestrians. These two types of pedestrians can also be described as“shoppers” and “elderly” respectively. T-tests conducted on these threepedestrian types showed significant differences in their walking speeds at
95% level. Table 3 shows the speed-flow functions calibrated for the three
types of pedestrians and the calculated speed at free flow for each case.

218

New Technologies for Urban Safety of Mega Cities in Asia
503

ICUS Report 6

Field Data

40

Greenshields
Underw ood
Speed (m/min)

35

Greenberg
May

30

25

20
0

10

20

30

40

Flow (/m /m in)

45
Field Data
BPR

40
Speed (m/min)

Overgaard
Davidson

35

30
25
20
0

5

10

15

20

25

30

35

40

Flow (/m /m in)

Figure 2: Pedestrian speed-flow plots of flow-speed functions (top)and capacity-restraint functions (bottom) for staircase
Table 3: Speed-flow functions for different types of pedestrianTypes ofpedestrianAll
Type I
Type II
Type IIIBest fit function
Greenberg: V = 260 S exp(-0.21 S)
Greenberg: V = 8.25 S exp(-0.081S)
Greenberg: V = 413 S exp(-0.24 S)
Greenshields: V = 3.89S + 0.124S 2

Speed atcapacity (m/min)
79.9
180.5
73.6
31.3

Type I pedestrians are typically workers going to work in the morning
who tend to be in a rush, especially when they notice their trains are
standing at the platform. Conversely, Type II pedestrians tend to walkslower as compared to working persons as they usually carry heavy bagswith them. They are not restricted by time constraints, or are simply
sluggish after sometime of shopping. They also tend to shop during off-peakhours where the shops and the MRT trains are less crowded. Of the three

Pedestrian Speed-Flow Model on Escalators and Staircases
504

219

October 2004, Agra, Indiapedestrian types, only the Type III pedestrian fitted a Greenshields model,
which produces relatively lower speeds at low flows. This is typical of theelderly, whose walking speeds are usually limited by their physicalcapability. The variability in walking speeds of different types ofpedestrians has shown to affect the parameters of the speed-flow functions.
In addition, the design of the staircase would also affect walking
speeds. Generally, a staircase that is poorly-designed would give rise tolower walking speeds. For example, staircases with high risers (Lam, et. al.,1995), narrow treads, as well as long flight of steps would tend to renderwalking more difficult and slower. Conversely, the provision of appropriate
handrails, intermediate step landings and visible markings on the edge ofeach step would allow pedestrian to walk easier and faster.
5.2 Escalator
Table 4 shows that the speed-flow models of the escalator approachdisplayed a higher explanatory power as compared to that for the staircase.
Similar to the staircase models, the Greenberg model produces the best fit
for the escalator approach, with a R2 value of 0.69. Figure 3 displays thevariations of pedestrian speed and flow data for the escalator approach, aswell as the fitted speed-flow models. The free flow speed on the escalator
approach is calculated to be 24.6 m/min, and the speed at capacity is 2.8
m/min.
Table 4: Speed-flow functions of escalator approach at Somerset MRT
stationRegression parameters
Model

EquationR2

Se

p-value(F-statistic)

Flow-speed functions
Greenshields V = 19.0S + 1.92S 2
Underwood V = 31.0S – 13.6 (S ln S)
Greenberg
V = 272 S exp(-0.66 S)
May
V2 = 182 S 2 ln(8.61 / S)

0.60
0.63
0.69
0.41

1.92
0.229
1.70
0.258

<0.01
<0.01
<0.01
<0.01

Capacity-restraint functions
Overgaard
S = 10.0 exp (-0.675 V/C)DavidsonS = 6.49 [1 + 0.0007 V /( C-V )] -1
BPR
S = 2.0[0.223+ 0.183(V/C)1.9]-1

0.52
0.03
0.52

0.278 <0.01
0.121 <0.01
0.0828 <0.01

The observed capacity of the escalator of 125 ped/m/min was only 56
per cent of the design operating capacity. The design capacity assumes an
occupancy value of 5 ped/m2 on the escalator, but it was not achieved evenduring very congested periods as passengers were not occupying gaps on theescalator. This could be because the pedestrian may desire to have a more
comfortable personal space and does not want to be too near the otherpedestrian in front of him.

220

New Technologies for Urban Safety of Mega Cities in Asia
505

ICUS Report 6


As noted earlier, the parameters of the speed-flow function is
influenced by the nature of the pedestrians. The earlier assumption of
constant speed on the escalator will no longer be valid if a substantial
number of pedestrians walk along the escalators. Unlike the staircase, thedifferences in walking speeds for different types of pedestrian were notsignificant due to the short length of the escalator approach.
Field Data

14

Greenshields
Underw ood

12
Speed (m/min)Greenberg
10

May

8
6
4
2
0

10

20

30

40

50

60

Flow (/m /m in)

Speed (m/min)14

Field Data

12

BPR

10

Overgaard
Davidson

8
6
4
2
0
0

10

20

30

40

50

60

70

Flow (/m /m in)

Figure 3: Pedestrian speed-flow plots of flow-speed functions (top) andcapacity-restraint functions (bottom) for escalator approach
6.0 CONCLUSIONSThis paper has examined the pedestrian flow characteristics along a
staircase and an escalator approach in a MRT station in Singapore.
Pedestrian flows on both the staircase and the escalator approach are best
represented by a Greenberg’s speed-flow model. It was found that the freeflow walking speeds on the facilities were 79.9 and 24.6 m/min, and thewalking speeds at capacity are 23.0 m/min and 2.8 m/min respectively.

Pedestrian Speed-Flow Model on Escalators and Staircases
506

221

October 2004, Agra, India
It is shown that the parameters of the model are dependent onpedestrian characteristics and facility designs. The fact that no single model
is able to fit all pedestrian facilities and types of pedestrians, indicates that
there are some areas where further work could be carried out, including
more data collection for larger range of flow conditions, as well as
estimation of models for other pedestrian facilities such as walkways andjunctions. Such works would increase the scope and depth of the research. It
is believed that the findings of the paper could provide some insight inpedestrian movements in underground stations that is useful for operationalor emergency planning purposes.
ACKNOWLEDGEMENT
The authors wish to thank SMRT Corporation Limited for its support
and cooperation during the survey at Somerset MRT Station.
REFERENCES
Bureau of Public Roads (BPR), 1964. Traffic assignment manual. Urban
Planning Division, U.S. Department of Commerce, Washington, D.C.
Daly, P.N., McGrath, F. and Annesley, T.J., 1991. Pedestrian speed/ flow
relationships for underground stations. Traffic Engineering and Control
32, 75-78.
Davidson, K.B., 1966. A flow travel time relationship for use in transport
planning. Proceedings Australian Road Research Board 3, 183-194.
Fruin, J., 1971. Pedestrian planning and design. Metropolitan Associationof Urban Designer and Environmental Planners, Inc., New York.
Lam, W.H.K. and Cheung, C.Y., 2000. Pedestrian speed/ flow relationships
for walking facilities in Hong Kong. Journal of Transportation
Engineering 124, 277-285.
Lam, W.H.K., Morrall, J.F. and Ho, H., 1995. Pedestrian Flow
Characteristics in Hong Kong. Transportation Research Record 1487.
Transportation Research Board, National Research Council, Washington,
D.C.
Overgaard, K.R., 1967. Urban transportation planning: traffic simulation.
Traffic Quarterly 21, 197-218.
Tanaboriboon, Y., Sim, S.H. and Chin, H.C., 1986. Pedestriancharacteristics study in Singapore. Journal of Transportation
Engineering 112, 229-235.
Virkler, M. and Elayadath, S., 1994. Pedestrian speed-flow-density
relationships. Transportation Research Record 1438. Transportation
Research Board, National Research Council, Washington, D.C.

222

New Technologies for Urban Safety of Mega Cities in Asia
507

TELEOPERATED SURVEILLANCE ROBOT
H. JAYARAM, M. VINOTH AND P. RAGHURAM
Department Of Mechanical Engineering
Amrita Institute of Technology, Coimbatore, India
jayvin_project@yahoo.co.in
ABSTRACT“Technology makes mistakes and tries to correct them”. Man started
the industrial revolution, it resulted in betterment of his life standards in one
aspect, but on the other hand it also resulted in hazardous Global warmingand Green house effect. Man made weapons of Mass destruction, which
threaten the existence of the world itself. The important question is that can
we just stop everything and get back to primitive ways of life. The answer
would definitely be NO. The thing we can do is reverse Engineer the
Problem and try to minimize its impact or find an alterative solution for the
problem. The ultimate aim of this project is to find in a small way analternative solution so that man can evade himself from the effects that hecaused for himself.
Tele-operated surveillance Robot was designed with keeping in mind
to counteract the hazards caused by chemicals. The Robot is a mobile
independent unit with toxic gas sensor attached to its end so that it keeps us
informed about possible gas hazard. There is a surveillance camera
attached to it so that the operator could see around the place. The Robot is
controlled by the computer through wireless network. As additional feature
the Robot is made Tele-operated, i.e., the operator can control the Robot via
the Intranet from a remote location.
1.0 INTRODUCTION
We know that more than half of the total population of the world
resides in Mega cities. Most of the major industries are situated in andaround big cities of the world. This may be good in socioeconomic point ofview but has negative impact on the society as a whole by the advent ofpollution and other hazards. Chemical and biological hazards are the newer
threats that are poised to mankind. The classic example is that of Bhopal
Gas tragedy, a lethal gas (methyl isocynade) leaked from a chemical factory
causing the death for more than 3000 people in the wake of the midnight.
The strategy that would have prevented the tragedy was simple; Methyl
Isocynate is highly hygroscopic gas when it comes into contact with water it
readily dissolves. Many lives could have been saved by a simple techniqueof warping wet cloth around the face. The problem was the absence to an
alarming device to indicate the leakage of the toxic gas.
The Tele-operated surveillance Robot’s main function is to survey anarea and warn people the presence of toxic. The use of chemical weaponryin warfare is becoming increasingly common, in such instances this Robot
223
508

October 2004, Agra, India

could be used to inform the soldiers of the possible lethal gas presence. The
ultimate aim of the project is surveillance in hazardous environments. The
Robots could be Tele-operated so the operator can control the Robot fromany place over the Network.
2.0 DESIGN ARCHITECUTRE FOR THE ROBOTThe design of the Robot is the most important part project. The
performance of the Robot is entirely dependent design of the Robot. The
design phase of the Robot can be classified into two sub phases.
 Navigation system
 Robot body
2.1 Navigation system design
There were certain constraints that were kept in mind while decidingof the navigation system, like movement in rugged uneven terrain’s, andharsh environments. There are various options that were available forchoosing of navigating the Robot like wheeled Robot, legged Robots,
serpentine Robots, and aerial Robots etc. The best-suited navigation systemfor our application was the wheeled Robots with tracks so that it is gives
high traction and capability of moving in rugged terrain. So the base of the
Robot was designed in a similar way to military tanks with tracks.
2.2 Robot body
The body for the Robot houses the drive motor circuitry and the sensor
circuitry and also the toxic gas-sensing probe. The surveillance camera ismounted on the independent rotary head of the Robot.

Figure 1: 3D Model of the Robot224

New Technologies for Urban Safety of Mega Cities in Asia
509

ICUS Report 6

An on-board camera, connected to the server though the video
transceiver, is placed on the front-top of the mobile robot in order to give the

Figure 2: Front View of the Robot
user a clear view of the environment in front of the robot. The video signal
from the camera is transmitted to the host computer through USB port.
The toxic gas sensing probes are attached to the body of the Robot asshown in figure. The body of the Robot also houses the battery for supplying
power to the actuators, sensors and also the camera. There are various
compartments on which the various circuitries like the WI-Fi circuitry andmotor drive circuits are placed.
3.0 ACTUATORS
There are many types of actuators that are available for the driving of
the motors like the hydraulic actuators, pneumatic actuators etc. The
problem with these types of actuators is that they are large, complex anddifficult to maintain. Most of the mobile Robots around the world use
Electric motors because of the simplicity in installation and control.
In our Robot we have used three hobby servomotors one for the rotaryhead mountings and the other two are for the independent wheels. The
servos has a three wire connection, one for common ground, one for power
and the last takes in position commands as encoded PWM (Pulse widthmodulation- a fixed square wave with variable work factor where a given
work factor percentage corresponds to given shaft position). Closed loop
position control is in-built in the servo package.
Controlling the position of the actuators is a simple by implementing
electronics system whose inputs correspond to suitable square waves in
outputs (Fig 3)
3.1 Control electronic for actuators
The electronics to drive the servomotors are simple and include an
voltage regulator (5-15V dc), a power on LED with respective current
limiting resistor and the heart of the PWM generating circuit; a PIC16F84A
controller from microchip with minimal peripheral electronics (20 MHz

Teleoperated Surveillance Robot

225
510

October 2004, Agra, India

crystal and condensers of the clock signal as well be describe, the use oflower frequency crystals is also possible but this will decrease the position
control resolution).
The basics role of the PIC controller is to accept serial data sent by any
serial device (typically a computer) and converting that information into
PMW position commands for a given (selected) servomotors. Further more
the PMW command should be held until another command for the same
servo is received.
There are 12 servo outputs available at ports PB0 through PB7 andPA0 through PA3 of the PIC16F84A. The controller needs two bytes of
information for each position command, one byte is for the selection of theservomotor (the address byte) and the other specifies the position of theselected servomotor (position byte).
4.0 MULTISENSOR SYSTEM
The important factor in Tele-operation is that the Robot must havehigh degree of local intelligence to deal with the problems caused by low
bandwidth and transmission delay of the Intranet. Baseline to achieve the local
intelligence desired at the remote site by knowing about the environment;
therefore the Robot is equipped with various sensors. The ultrasonic sensors
and toxic gas sensors are used on our Robot to attain partial autonomy. The
information reported to the operator is mainly of symbolic feature and are
indispensable for Tele-operation.
4.1 Ultrasonic sensors
Around the base portion of the Robot, array of ultrasonic sensors areplaced. The feature of this Ultrasonic sensor system is its flexibility to be
operated in different measurement modes. The activation of the sensors canbe altered on line. The purpose of mounting this sensor is obstacle
avoidance. The obstacle is detected in advance so that the operator canmaneuver the Robot to avoid collision.

226

New Technologies for Urban Safety of Mega Cities in Asia
511

ICUS Report 6

Figure 4: Control electronics for Robot’s actuator
4.2 Toxic gas sensing
A commercially available toxic gas sensor is mounted on the Robot.
The two sensor probes are mounted on each of the arm. The sensors areoperated by independent the battery unit. The sensor signals are transmitted
to the computer via RS232 serial port.
4.3 Active vision system
The visual surveillance of the remote location is brought about withthe help of CCTV camera. The camera is mounted on the Rotary head thatthe operator can control.
5.0 HARDWARE ARCHITECTURE
The architecture we follow is client-server wherein the robot isconnected to a central server, which can be accessed by the client user froma remote location. The configuration of our current system hardware isshown in Fig. The remote client will be able to control the movement of the
Robot as well as receive the sensor input from the ultrasonic sensor and the
toxic gas senor thro’ the LAN cable. The interface between the Server
computer and the Robot is by wireless serial port so that the Robot will beable to move independently.

Teleoperated Surveillance Robot

227
512

October 2004, Agra, India

Figure 5: Hardware Architecture
5.1 Visual feedback module
The continuous and steady image stream feedback from the robot site
is necessary when the client users control the mobile robot at the client site.
Moreover, the image quality should be good enough to provide as muchinformation as possible about the remote site for Tele-operation. An onboard camera, connected to the server though the video transceiver, isplaced on the front-top of the mobile robot in order to give the user a clear
view of the environment in front of the robot. The video signal from thecamera is transmitted to the host computer through USB port.
The transmission of video images through the intranet is done byconverting the camera image into a stream of still images of JPEG or the
GIF format. In the system, the images are captured from the frame grabberbased on the bt848 chipset and compressed to JPEG format by software
implemented in C++. Then still images are sent at fixed intervals of timeand on the client side the reconstruction of the image takes place once theentire frame is received and displayed.
6.0 SOFTWARE ARCHITECTURE
As already mentioned, the Robot is computer controlled, theactuation signals to the on-board control a circuit is done by giving signal
via the serial port. Software must be developed to control the motion of the
Robot and also display the video image and sensor input.

228

New Technologies for Urban Safety of Mega Cities in Asia
513

ICUS Report 6

Figure 6: Video Transmission

Figure 7: Graphical User Interface

6.1 Graphical user interface
Since a Tele-robotic system involves the interaction between humans
and robots, a friendly user interface is necessary to assist the human operator.
A user friendly GUI was created using Visual Basic which will incorporate,
Robot motion control module, Video input and the sensor input.

Teleoperated Surveillance Robot

229
514

October 2004, Agra, India

7.0 CONCLUSION
Man cannot work in hazardous environments; in that case it is possible
to him to use Robots for doing the intended work. The Tele-operation of
Robots means that the controller need not be at the site of the operation,
which is dangerous. The application of Robots to in Urban Search andRescue (USAR) is now quite a common. Similarly this Tele-operated Robotin future will play a vital role in the future for urban safety. The current
intended application of toxic gas detection is very vital to prevent massdisasters like that of the Bhopal gas tragedy. The further work involves inmaking the Robot completely autonomous and multi-purposed such a fire
detection, material handling etc. The Robot could be put on the Web so thatthe operator can control the Robot from any part of the world.
REFERENCES
Andreas Birk and Holger Kenn.,2002. RoboGuard, A Teleoperated Mobile
Security Robot, Control Engineering Practice. Volume 10, no 11,
pp.1259-1264, Elsevier.Michael Wandel, Udo Weimar, Achim
Lilienthal, Andreas Zell.,1998 . Leakage localization with a mobile robot
carrying chemical sensors.
L. Feng , J. Borenstein , D. Wehe,.1996. A completely wireless development
system for mobile robots. Proceedings of the ISRAM Conference,Montpellier, France.
Donny A. Ciccimaro, H.R.Everett,Gillbreath,G.A.,Tran, T.T.,1998. An
Automated Security Response Robot. SPIE mobile Robots XIII, Boston,MA.
Ronald Siegwart, Patrick Saucy., 1999. Interacting mobile robots on theWeb. ICRA’99,Detroit, MI, USA.
Everett,H.R., 1995. Sensors for Mobile Robots: Theory and application.
A.K. Peters Ltd., Wellesley, M.A

230

New Technologies for Urban Safety of Mega Cities in Asia
515

ICUS AND AIT COLLABORATION
ON URBAN SAFETY RESEARCH
DUSHMANTA DUTTA1,2 AND TAKETO UOMOTO2
1
RNUS, SCE, Asian Institute of Technology, Thailand
2
ICUS, IIS, University of Tokyo, Japanddutta@ait.ac.th
ABSTRACTOver half of the world’s population is concentrated in urban areas
covering just 4% of the world’s surface. Mega cities in particular arecharacterized by a high population density and tremendous pressure on
supporting infrastructure. It is estimated that by 2015, Asia will be host to
more than 50% of the mega cities in the world. A phenomenal growth in thenumber of high-rise buildings and other infrastructure in these cities isclearly foreseen, though a balance is often not ensured with measures fortheir maintenance.
Safety of infrastructure is foremost important for sustainableurbanization and economic development in Asia. With this realization, on
October 29, 2002 the International Center for Urban Safety Engineering(ICUS) of the Institute of Industrial Science, the University of Tokyo, Japanand the School of Civil Engineering of the Asian Institute of Technology
established a Regional Network Office for Urban Safety (RNUS) to promoteand enhance high quality cooperative research in areas related to urban
safety in Mega cities of Asia and to nurture scientists of international
stature and achievements. This paper presents the collaborative activities
initiated by AIT and ICUS through RNUS for urban safety in the South andSouth-east Asian region.
1.0 INTRODUCTION
With the rapid economic development in the last few decades, there
has been a phenomenal growth of high-rise buildings and otherinfrastructure in mega cities in Asia. However, this growth in infrastructure
is not adequately balanced in appropriate measures for their maintenanceand management. This has led to deterioration of urban infrastructures andresulted in urban disasters in many cities. Recently, the issue maintenance ofurban buildings and infrastructure in Japan has been sensationalized bymass media after several incidents of falling blocks from concrete structures,such as bridges and tunnels in different parts of Japan (Larimer, T., 2000).
The frequency of floods in Asia has doubled in the last 30 years. The rate ofincrease of urban flood frequency is more prominent in the last 10 years,
especially, in the recent three years statistics show rapid increase of floods
in Asian cities (Dutta, 2003). Kobe Earthquake disaster of 1995 clearly
showed the vulnerability of our cities against earthquake disasters.

1516

October 2004, Agra, India

The recent developments in various advanced technologies including
remote sensing, GIS and other computational tools have generated scopeand motivation to focus on devising appropriate methodologies for
management and maintenance of urban buildings and infrastructures forsustainable development of the Asian mega cities with adequate safety andsecurity.
The International Center for Urban Safety Engineering (ICUS), a
research center located at the Institute of Industrial Science of the Universityof Tokyo, Japan, focuses on research and developments in the field of urban
safety engineering including maintenance and management of
infrastructures with new technologies from a global perspective. ICUS
emphasizes on collaboration in research with international organizations
particularly in Asian region. To strengthen its collaborative research efforts,
there have been several activities undertaken by ICUS (Dutta and Uomoto,2002; Misra and Kato, 2003). One of the most significant steps for
expanding its collaborative activities is the establishment of a Regional
Network Office for Urban Safety (RNUS) in Thailand. RNUS wasestablished on October 29, 2002 at the School of Civil Engineering (SCE) of
the Asian Institute of Technology (AIT) to work in areas of mutual interestof SCE and ICUS for the advancement of urban safety engineering utilizing
advanced engineering tools. AIT is a regional international and non-profit
institute with the vision of becoming a leading and a unique regional
multicultural institution of higher learning, offering state of the art education,
research and training in technology, management and societal development.
ICUS and AIT signed an agreement towards developing joint research
programs and to cooperate in developing strategies for tackling issues
related to urban safety through RNUS (Photo 1).

Photo 1: Opening ceremony of RNUS at SCE/AIT

2

New Technologies for Urban Safety of Mega Cities in Asia
517

ICUS Report 6

RNUS focuses on collaborative research activities with different
organizations in Asian countries in areas of urban safety engineering withadvanced technology tools such as numerical models, remote sensing, GIS,
GPS, etc. for devising appropriate methodologies for management andmaintenance of urban buildings, infrastructures, mitigation of urban
disasters and environmental problems for sustainable development of Asian
cities with adequate safety and security.
2.0 OBJECTIVES OF RNUS
Through RNUS, SCE and ICUS work together for:advancement of urban safety engineering utilizing advanced
engineering tools,
establishment of collaborative research activities with otherorganizations in areas of urban safety engineering in Asian region,andestablishment of a regional network of researchers for sharing
information and resources in the field of urban safety engineering.
3.0 FUNCTIONS OF RNUS
RNUS spearheads initiative of collaborative research projects withresearchers from Thailand and other Asian countries and sharing of
information through the following activities.
Fundamental Research
Collaborative Research Projects
Information Dissemination(Meetings/Seminars/Workshops/Symposia/
Conference/Publications)
Network of Researchers
Exchange of Staff
4.0 HIGHLIGHTS OF RECENT ACTIVITIES
Since its inception, RNUS has undertaken several activities including
collaborative research projects with researchers of AIT and otherorganizations in Asia, seminars and workshops.
4.1 Collaborative research projects
With the support of ICUS, two pilot projects were initiated by RNUS
in Bangkok, Thailand immediately after its establishment. In the past year,
RNUS has received funding from different international organizations for
conducting collaborative research projects. This section briefly introduces
the on-going research projects at RNUS.
4.1.1 Development of database for deteriorated concrete bridges
This is one of the two pilot projects initiated by RNUS in collaboration
with the researchers, scientists and engineers of Thailand as a start-up

ICUS and AIT Collaboration on Urban Safety Research518

3

October 2004, Agra, India

activity of the center. The participatory organizations in this project are
RNUS, ICUS and the Thammasat University, Thailand. Under this project,a database for deteriorated concrete Bridges in Bangkok has been developed.
The databased provides detailed information of bridges under thesuperintending of Bangkok Metropolitan Authority (BMA) including name,location, type of structure, dimension of structure, year of construction, etc.,
in order to subsequently create GIS of bridges in Bangkok for operation,
repair, and maintenance of the structure (Tangtermsirikil, et al., 2003; Kato,et al., 2003).
4.1.2 Urban flood risk mapping using GIS, RS and mathematical modelThis is the second pilot project initiated by RNUS. The organizations
involved in this project are RNUS, ICUS, AIT, Chulalongkorn University,and GISTDA (Geo-Informatics and Space Technology Development
Agency, Thailand). Two of the most frequently flood affected districts of
the Bangkok Metropolitan area are selected as the study area of this pilot
project. The selected districts are Bangkapi (Area: 28.5 km2, population:
0.143 million) and Bungkum (Area: 24.3 km2; population: 0.137 million),
both are adjacent districts located in the eastern side of the Bangkok City
(Fig. 1). The project consists of three components; 1) development of flood
loss functions for economic loss estimation; ii) development of urban
building and infrastructure inventory and iii) flood modeling using a
distributed flood model. Flood risk maps can be developed by integrating
the outputs of these three components. The first two components of the
project have been already completed (Dutta and Tingsanchali, 2003; Dutta
and Serker, 2004).

Figure 1: Location map of the study area

4

New Technologies for Urban Safety of Mega Cities in Asia
519

ICUS Report 6

4.1.3 Urban flood modeling in mekong river basin
This is a research project that aims at developing a system for urban
flood inundation simulation in the Lower Mekong river basin. The project
mainly focuses on physically based surface-river modeling for floodinundation simulation. The system has been developed with the objective ofintegrating it with airborne and space borne resources and numerical
weather prediction models for designing an integrated flood warning system.
An existing mathematical model has been modified and improved for floodmodeling in the lower Mekong basin. The details of the project arepresented by Dutta et al., 2004 in this symposium and included in thisproceedings.
4.1.4 Socio-economic impact assessment of floods in coastal cities underclimate change
RNUS receives an award from the Asian Pacific Network on Global
Change (APN) to conduct a research project titled "An Assessment of theSocio-economic Impacts of Floods under Climate Change Conditions in
Large Coastal Cities in South and South-east Asia". The project focuses onunderstanding the flooding characteristics under projected climatic andsocio-economic scenarios. It will integrate and analyze existing data,
information and results and use existing tools for simulating the flood
behavior and impacts. The project scope is limited to selected low-lying
large cities of the participating countries: Bangladesh, India, Pakistan, Sri
Lanka, Thailand and Vietnam. One city from each country is identified
based on their representativeness for the study. The research also focuses on
identifying critical gaps in information and policy and a set ofrecommendations will be made for better decision making to improve thelivelihood of the local people. The project duration is one year. Figure 2
shows the approach and possible outcomes of this project.
4.1.5 Risk analysis due to catastrophic floods in mega cities
RNUS receives a sponsored research project grant from the United
Nations University (UNU) for conducting this research project on "Risk
Analysis due to Catastrophic Urban Floods using GIS, Remote Sensing and
Surface-River Model". In this project, RNUS will conduct a case study in
Bangkok city for risk analysis due to catastrophic urban flooding. The work
covers simulation of catastrophic floods due to extreme rainfall events andassessment of its socio-economic impacts using an existing urban flood risk
assessment model in a part of the Bangkok city, which is most vulnerable tofloods. Risk maps will be prepared using GIS for the simulated catastrophic
flood events for existing socio-economic situation. The 15-month longproject is started from September 2004.

ICUS and AIT Collaboration on Urban Safety Research520

5

October 2004, Agra, India

Selected coastal cities
in project
Pakistan

DEM
India

Bangladesh

Bay ofBengalLand Use

Spatial databasecollection

ThailandSri Lanka

Vietnam

Network of researchers
communication

Rainfall
Evaporation

Soil condition
River Network

Extracted informationfrom remote sensing
Projected time series
Database from GCM

Downscale

Sea Level
Tools for simulation
Population
Economic
activities

Socio-economic
database

Flood inundation simulation

Structure
inventory

Send outcomes todecision makers
for devising policy
Socio-economic risk assessment
for different scenarios

Other related internationalorganization

Figure 2: Approach and expected outcomes of APN funded project4.1.6 Real-time flood forecasting and decision-making system for ChaoPhraya river basin, Thailand
RNUS collaborates with the Water Engineering and Management
Field of Study of SCE, AIT for this two-year long period project on"Development of Real-time Flood Forecasting and Decision-Making
System of Chao-Phraya River Basin, Thailand" funded by NECTEC,
Thailand. In this project, a real-time flood forecasting and decision-making
system will be developed for the Chao-Phraya River Basin, Thailand byintegrating a physically based distributed hydrological model developed at
the University of Tokyo and a hydro-dynamic model for floodplain
developed at AIT.
4.2 Information dissemination
RNUS has been organizing academic seminars at AIT in regularinterval by inviting prominent researchers on various issues related to urban
safety. It has also organized two workshops.
4.2.1 Seminars
So far, RNUS has organized six seminars on different themes related
to urban safety at AIT. Table 1 shows the seminar titles, speakers and dates.

6

New Technologies for Urban Safety of Mega Cities in Asia
521

ICUS Report 6

4.2.2 Workshopsa) Workshop on collaboration between yamanashi university, japan andresearch organizations in thailand
RNUS assisted the University of Yamanashi, Japan in organizing
activities of the Workshop on “Collaborative Research and Education
Program of the University of Yamanashi COE with Thai Organizations and
AIT” that was held on 25 November, 2003 at the Conference Center of AIT.
The objective of the workshop was to establish a strong tie for researchcollaboration between the University of Yamanashi, Japan and various
water-related Thai organizations associated with AIT. Several experts from
AIT and Thai organizations presented papers on hydrology and water
resources in Thailand, water use management, water quality and solid waste
management, among other topics.
No.
1
2
3

4

5

6

Table 1: Seminars organized by RNUS
Seminar Title
Speakers (Affiliation)

Date

Water Resources in the 21stCentury under Climate Change
Scenarios
Applications of Hyperspectral
Remote Sensing

Dr. T. Oki, Dr. S. Kanae and Mr.
Nov. 14,
K. Yoshimura (University of
2003
Tokyo)
Dr. T. Endo (University ofFeb. 24,
Tokyo)
2004
Feb. 27,
Remote Sensing from Local to Prof. Y. Yasuoka (University of
2004
Global Scale: Catering the Need Tokyo) and Dr. D. Dye (Frontierst
Research
Systemfor
Globalof The 21 Century
Change, Japan)
Numerical Models in Fluid and Dr. K. Nakayama (National Mar. 02,
Their Applications
Institute
for
Land
and
2004
InfrastructureManagement,
Japan)
Maintenance of Concrete
Dr. Y. Kato and Ms. M.
Mar. 12,Structures and Retrofitting
Yoshimura, (University of Tokyo)
2004
Promotion System for Low
Earthquake-Resistant Structures
Catastrophic Disaster Risk
Dr. S. Herath (UNU, Tokyo) And
Jul. 17,
Management for Sustainable
Dr. Rajib Shaw (Kyoto
2004
Urbanization in Asia
University)b) Third international workshop of WSSIRNUS spearheaded the organization of the 3rd International Workshop of
the World Seismic Safety Initiative (WSSI) on “Seismic Risk Management
for Countries of the Asia Pacific Region” at the Miracle Grand Hotel in
Bangkok during 7-8 December, 2003. WSSI is an undertaking of theInternational Association for Earthquake Engineering (IAEE) in support of
the International Decade for Natural Disaster Reduction (IDNDR) of theUnited Nations. Since its inception in 1992, WSSI has been working withmany countries around the world through its programs. To utilize and sharethe experiences learnt over the past ten or more years, WSSI 2003 wasorganized to allow participants: 1) to learn from countries where WSSIICUS and AIT Collaboration on Urban Safety Research522

7

October 2004, Agra, India

Photo 2: A snapshot during the workshop
programs have made positive difference in terms of risk mitigation andmanagement; 2) to learn from countries where WSSI programs have notmade any major impact in terms of risk mitigation efforts, and 3) to develop
a plan in consultation with all the attending countries about what WSSI
should do for the next five years and where they should focus their humanand financial resources. The workshop was attended by over 55
representatives from 19 countries.
RNUS also spearheaded the editing activities of the final this WSSI
workshop (Meguro et al., 2004). The proceedings include country reports
from 12 countries, reports on inter-national cooperation of JICA and reports
from other International Organizations. The country reports emphasized on
the earthquake risk mitigation efforts, strategies, responses and assessment
measures initiated in their respective countries. Most of the country reports
focused on seismic risk management activities in the last five years, scopefor future collaborations in the region for varied resources and further
networking and information-sharing with international organizations.

Photo 3: WSSI workshop participants in a group photo
8

New Technologies for Urban Safety of Mega Cities in Asia
523

ICUS Report 6

5.0 CONCLUSIONS
Rapid urbanization is a distinctive feature of Asia in addition to atremendous rate of population growth. It is estimated that by 2015, morethan 50% of the mega-cities of the world are going to be in Asia and theirurban development is going to continue in the decades to come. For
sustainable urbanization, holistic efforts are needed for urban safety andsecurity. New technologies have inspired us to conduct research for new
development in urban safety engineering, which should be integrated withsocio-economic and environmental aspects to achieve the sustainable urban
development for safer and securer 21st century. International collaboration
among researchers and other stake holders is needed to target the local andregional problems with shared knowledge and technologies. RNUS is an
initiative of ICUS, the University of Tokyo and SCE, AIT in this direction
and its success is a demonstrative example to inspire further collaborative
efforts in the region. There is still much to do for RNUS to expand its
activities of collaboration, which will in turn lead to regional collaborationand networking.
REFERENCES
Dutta, D. and T. Uomoto 2002 (ed.). Urban Safety Engineering 2001.
Proceedings of the Joint Workshop, ICUS/INCEDE Report 1, October.
Dutta, D. (2003). Analysis of Urban Flood Disaster trends in Asia.
Watershed Hydrology: Proceedings of the International Conference on
Water and Environment, Bhopal, India, December, pp.512-519.
Dutta, D. and T. Tingsanchali 2003. Development of Loss Functions for
Urban Flood Risk Analysis In Bangkok. Proceedings of the 2nd
International Symposium on New Technologies for Urban Safety ofMega Cities in Asia, ICUS, IIS, The University of Tokyo, October, pp:229-238.
Dutta, D. and K. Serker 2004. Urban Building Inventory from Very High
Resolution Remote Sensing data for Bangkok City, Seisan-Kenkyu.
Journal of Institute of Industrial Science, University of Tokyo, Vol. 56,
No. 3, pp. 27-30.
Dutta, D., M. J. Alam and S. Hironaka 2004. Urban Flood Modeling in
Lower Mekong Basin Using a Distributed Surface-River Model.
Proceedings of the 2nd International Symposium on New Technologies
for Urban Safety of Mega Cities in Asia, Agra, India, October 18-19.
Kato, Y., S. Tangtermsirikul and T. Uomoto 2003. Construction of a
Database for Deteriorated Concrete Bridges: Filed Research Report inCompany with RNUS, ICUS/INCEDE Report No. 3, ISBN4-9901475-37.
Meguro, K., D. Dutta and T. Katayama 2004 (ed.). Seismic Risk
Management in the Countries of Asia and Pacific. Proceedings of theThird WSSI Workshop, ICUS Report 5, The University of Tokyo, Japan,
312 pages, ISBN4-9902067-0-3.
Misra, S. and Y. Kato (2003) (ed.). New Technologies for Urban Safety ofMega Cities in Asia, Proceedings of the International Symposium, ICUS
Report 3.

ICUS and AIT Collaboration on Urban Safety Research5249

October 2004, Agra, India

Tangtermsirikil, S., T. Kaewkhluab and K. Kaewmanee 2003. Information
Acquisition and Structural Health Monitoring of Bridges in Bangkok,
Proceedings of the 2nd International Symposium on New Technologies
for Urban Safety of Mega Cities in Asia, ICUS, IIS, The University ofTokyo, October, pp: 133-140.
Larimer, T. (2000). The Sky is Falling. Time Magazine, USA, January 24,
2000.

10

New Technologies for Urban Safety of Mega Cities in Asia
525

SAFETY ASSESSMENT OF EXISTING
ROAD IN THE HIMALAYAS USINGGEOGRAPHIC INFORMATION SYSTEMAND SATELLITE IMAGERYSHARAD VIMAL OBEROI1 AND NARINDER KUMAR THAKUR2

Institute of Technology,Banaras Hindu University, Varanasi, IndiaSnow and Avalanche Study Establishment (SASE), Chandigarh, India
svoberoi11@yahoo.co.in
ABSTRACT
Remote sensing has been used to study characteristic properties ofground surface due to the advantages of its broad area observation andperiodicity. Geographic Information System (GIS) has also proved to be an
ideal tool for hazard modeling owing to its versatility in handling a large setof data, providing an efficient environment for analysis and powerful set oftools for collecting, storing, retrieving, transforming and displaying spatial
data. Therefore the integration of GIS with remote sensing data andthematic maps can facilitate greatly the assessment and estimation ofregional natural hazards.
The present paper explores modern GIS in the routing and alignmentof hill road network because of the immense benefits it can offer to planners
by identifying the landslide and avalanche prone areas. The roads existingin the Himalayas are subjected to frequent avalanches and landslides,
thereby causing fatal casualties and heavy damages to scarce man-madefeatures. The application of remote sensing in transportation has thepotential capability to provide information that can reduce the risks
involved.
It is expected that such risk assessment of the existing infrastructure
will help in formulating the necessary precautions to be taken during theplanning stage of a project, so as to minimize any possible future human orproperty losses in case of a calamity.
1.0 INTRODUCTION
With the rapid growth in population and immense pressure on theexisting facilities, today urban growth is extending into hazard prone
regions. The result is that the magnitude of the impact of a disaster increases
since it is dependent on the susceptibility of the land and the vulnerability ofthe society (Verstappen, 1995). The vulnerability is also compounded with
the increased complexity of interdependent systems (Comfort, 1999).
Natural disasters happen every year and their impact and frequency
seem to have greatly increased in recent decades, mostly because of

11526

October 2004, Agra, India
environmental degradation, such as deforestation, intensified land use, andthe increasing population (Vincent, 1997). With today’s complexity ofsociety, response and relief from disasters has become a costly concern.
Therefore, there is a need to shift to mitigation, which entails activities thatstrive to reduce the number of hazards and/or their impact before disasters
happen (Comfort, 1999).
According to Verstappen (1995), the purposes of using remote sensing
include: “to investigate the susceptibility of the land and the vulnerability ofthe society, to construct hazard zoning maps and potential damage maps, tomonitor potential hazards, and to deal with emergency situations after adisaster.” Many research studies have been completed that employ remotesensing as the principal information source in the assessment of
hazards/disasters. But, not all of the applications are suitable for use in thetransportation domain, because of the higher spatial and temporal resolution
required for many of the specific applications. Given the importance oftransportation in our daily lives, there is a desire to ensure the safety andoperation within each of the transportation domains (Gamba et al., 1998).
This is another reason why there is a growing interest in using remotesensing to predict, monitor, and assess disasters.
In this study, the authors have attempted to operationalise a working
methodology wherein geo-environmental parameters are analyzed todevelop models for mapping the hill areas prone to the regional natural
disasters (namely avalanches and landslides) using remotely sensed data andGeographic Information System (GIS).
2.0 AREA OF STUDY
The Indian Himalayas stretch from east for about 2500 km across 72o
E to 96o E longitude and 26o N to 37o N latitude. The complex folding
pattern that they have been subjected to during the upheaval of Himalayas in
Pleistocene and subsequent period leading to thrusting of Indian plate withEurasian plate, has lifted the rock structure to produce a long chain of
mountain ranges with deep furrow in between. The interaction of global
atmospheric circulation system with the tallest geological feature of theearth has produced diverse climatological, biological and snow climatic
zones within the Himalayas. This complex variation is unparalleled in theworld (Sharma et al., 2000).
Limited numbers of roads existing in the Himalayas are subjected tofrequent avalanches and landslides thereby causing fatal casualties andheavy damages to scarce man-made features. Moreover, the planning andlaying out of roads in the mountains is a very slow and cumbersome process,owing to the difficult terrain with ice-fields, snow-covered peaks and veryharsh climatic conditions. The Himalayan region of India is normallycovered by snow melting during the winter season. The region is cut-off for
most part of the year from the rest of the world and the passes only provide
the routes of communication. The strategic importance of some of these12

New Technologies for Urban Safety of Mega Cities in Asia
527

ICUS Report 6areas makes it more important for the roads to be kept open during adverse
weather conditions.
The area of study lies along the Manali-Leh Highway from Manali toDarcha for a stretch of about 138 km, which falls in the Lower and Upper
Himalayan snow climatic zone. The altitude in this area varies from 1800 to
6200 m. The road is under heavy use by the army and civilians, which
underlines its significance in connecting this treacherous landscape to themainland.
3.0 METHODOLOGY OF SAFETY ASSESSMENTAs the project area is vast and covers heterogeneous terrain the authors
have felt that a model addressing the expert knowledge combined with astatistical technique will suffice the need. In this method, expert opinions
are employed to determine how each parameter of the terrain and categories
within the parameters respond to landslide/avalanche susceptibility. This issubsequently used to classify the area into ranks, which are translated toweightages using the models. Decision space software, Landslide Hazard
Zonation and Avalanche Modeller have been used for the generation of thehazard maps.
4.0 SAFETY ASSESSMENT WITH RESPECT TO LANDSLIDES
Landslide is a rapid disaster that usually happens in an unstable slope
region, which always includes the falling, sliding or flowing of soil and rock.
Every year, landslides cause the death or injury of thousands of people andmillions of rupees of property is lost (Raju et al., 1999). Prediction ofpotential landslide areas has been very difficult because of the complexity of
the factors involved and their relationship to each other, which is wide
ranging (Yuan et al., 1997). Normally the causes of landslide are determinedby carrying out some sampling of the soil, rock, slope inclination, land
cover, underground water level, geology, etc. at the site. It is difficult andtime-consuming to do this for a large area from time to time and byintegrating it with GIS, all the information can be combined, manipulated
and analyzed to determine potential landslide areas very quickly and more
efficiently.
Among the various methods for landslide hazard zonation, theprobability of occurrence of mass movement has been calculated: (a) basedon the various terrain parameters and their cumulative influence, and (b)knowledge-based classification (Van Westen, 1994). It is expected that thepresence of terrain attributes similar to that of the observed/reported slide
elsewhere, is likely to induce slide under the given triggering conditions.
Therefore, based on the spatial and temporal distribution of the landslides
and their triggering factors, it is possible to identify areas susceptible tosimilar slide (Nagarajan et al., 1998).

Safety Assessment of Existing Road in the Himalayas using GIS and Satellite Imagery
528

13

October 2004, Agra, India


4.1 Factors causing landslides
Previous studies have amply demonstrated that landslides are
predictable if terrain characteristics are available. The factors generally
attributed to cause landslides are lithology, geology, slope-dip (beddingjoint) relation, geomorphology, drainage, slope angle, slope aspect, slope
morphology, land use, soil texture, etc. All these have been incorporated in
the present study, along with the triggering factors like rainfall, snow
ablation, earthquake and anthropogeny. However, it is impossible to exactly
predict when and where a landslide will occur because the relationshipbetween the factors mentioned above is complex (Shikada et al., 1997).
4.2 Methodology
The methodology was divided into the following steps:
 Selection of area of interest.
 Generation of precision geocoded LISS-III data along the route.
 Preparation of base maps using Survey of India (SOI) toposheetwise on scale 1 : 50000 with base details.
 Visual interpretation of satellite data for generation of thematicmaps.
 Model description with standardization of parameters.
 Ranking i.e. pair-wise comparison in hierarchical approach (basedon expert opinions).
 Landslide management map along the area of study and toposheetwise output.
 Final maps i.e. Landslide Hazard Zonation Maps.
The Landslide Hazard Zonation (LHZ) Maps were classified into
various categories based on the parameters described in Table 1.
Table 1: Assignment of ranks and triggering parameters for landslides
Landslide
Susceptibility
Very High
High

Slope
(o)
36-54
18-36

Moderate

>54

Low

0-18

Land use

Rainfall Snow
Geology Tectonic(mm) Ablation
Zone
Barren land 451-600
Grasslands/ 301-450
1800 to Youngfold Seismic
Pastures
Forested
151-300 4000 m mountains ZoneIV
Area
Settlements
0-150

5.0 SAFETY ASSESSMENT WITH RESPECT TO AVALANCHES
The major avalanche activity in our area of study is along various
nallas that drain into Indus and other rivers. The snow cover in this area islikely to evolve under cold climatic conditions. In this context a systematic

14

New Technologies for Urban Safety of Mega Cities in Asia
529

ICUS Report 6

study has been carried out to delineate the avalanche-prone areas. The
information about the study area was gathered by conducting ground/aerial
reconnaissance.
The remote sensing techniques comprising of Digital Elevation Model(DEM) analysis, preparation and visualization of map and satellite data
(IRS-1C/1D LISS-III) were carried out using ERDAS Imagine 8.4 software,
run under Windows 2000 Professional environment because of its
sophisticated procedures for satellite and vector data processing. The
avalanche hazard maps offer an effective way to guide and educate the users
about the avalanche-prone areas and their possible preventive measures.
This technique is user-interactive and offers better visual interpretations thatare lacking in conventional techniques, which use toposheets as a visualsource of information.
5.1 Methods of investigations
The slope, aspect and terrain configurations are derived from DEM
using precise geo-referenced topographic digitized data. The terrain
configuration has been interpreted using DEM along with the ground datacollected during the ground reconnaissance conducted. The ground coverparameters have been derived from the appropriate data selected after thedetailed analysis of multi-date IRS-1C/1D LISS III data using image
processing techniques. It has been found that the selected data provides upto-date information for classification of ground cover. The same confirms to
the ground data collected during ground recce carried out earlier.
5.2 Data type and sources
The data type and sources used for each parameter are discussed inTable 2.
Table 2: Data used for avalanche hazard zonation mapping
S.No.

Details

01

Data
Type

02
03

Accuracy
Data
Format+/- 6 mArc Info
Generate+/- 6 mArc Info
Generate

04

Data
Collector
Provider

SASE

SASE

Digitaltopographic
contours/
Satellite
imagery+/- 6 mArc Info
Generate .img/.
pix
SASE

SOI 1972
editionSOI 1972
edition

SOI /IRS
1972/2000

05

Slope

AspectDigitalDigitaltopographic topographic
contours
contours

Configuration

Safety Assessment of Existing Road in the Himalayas using GIS and Satellite Imagery
530

Groundcover
IRS-1C/1D
LISS-III.img/.pix (4bands)
SASE
August2000

15

October 2004, Agra, India


5.3 Generation of cartographic model
A cartographic model of data and analytical methodology has been
illustrated in Figure 1. LISS-III data has been geo-referenced by using welldefined 25 ground control points, which were established during the groundrecce to achieve higher accuracy. The LISS-III data has been then classified
for calculating the total area for each class of the ground cover (rocky,
barren and grassy).
The DEM gives a realistic view of the area and makes it easy tounderstand the planar nature of the area. Different terrain features e.g. hills,
valleys, gorges and configuration can be identified with ease. For analyzing
ground-cover parameter, the LISS-III data is used.

Figure 1: Cartographic Model
6.0 RESULTS AND DISCUSSION
6.1 Landslide hazard zonation
Since the study of the meteorological data for the region revealed
negligible liquid precipitation in the areas beyond the Rohtang Pass (Lahaul& Spiti), rainfall was assumed to be uniformly distributed for the Kulu

16

New Technologies for Urban Safety of Mega Cities in Asia
531

ICUS Report 6District areas, situated before the Rohtang Pass only. Therefore, the LHZ
model gives no results for the region beyond the Rohtang Pass. However, it
should be kept in mind that any precipitation that may take place in thismountain desert causes immense havoc, because of the loose soil andboulders present. The percentage of the different risk zones of the study area
is given in Table 3 below.
Table 3: Percentage of different risk zones of the study area
S. No.
01
02
03
04

Degree of Susceptibility toLandslides
Low
ModerateHigh
Very high

Percentage of Total Susceptible
Area
10.32 %
43.83 %
44.84 %
1.01 %

Darcha

KyelangRohtang Pass

SCALE
4

Manali0

4

8 kilometers



LEGEND
Low
ModerateHigh
Very highFigure 2: Landslide hazard zonation map of Manali-Darcha region
considering rainfall only up to Rohtang Pass

Safety Assessment of Existing Road in the Himalayas using GIS and Satellite Imagery
532

17

October 2004, Agra, India


6.2 Avalanche hazard investigations
The Avalanche Hazard Zonation Map was prepared to identify theformation zones of avalanches in the hilly terrain based on the DEM, which
gives a realistic view of the area and makes it easy to understand the planar
nature of the area. Different terrain features like hills, valleys, gorges andconfiguration were identified and all the thematic layers were overlaid.
A total of 90 avalanche sites have been mapped along the different
axes in the Manali-Darcha area as shown in Figure 3. It has been correlatedwith the ground data collected during reconnaissance surveys, as depicted in
Figure 4. This information has significant role for users in the operational
areas for visual interpretation of terrain and prediction of avalanche prone
areas.
Darcha

KyelangRohtang Pass

SCALE
4

0

Manali4

8 kilometers



LEGEND
Avalanche prone area

Figure 3: Avalanche hazard map of Manali-Darcha region draped on
IRS-1C LISS-III image

18

New Technologies for Urban Safety of Mega Cities in Asia
533

ICUS Report 6Darcha

KyelangRohtang Pass

SCALE
4

Manali0

4

8 kilometers



LEGEND
Avalanche prone area

Figure 4: Avalanche-prone areas identified by ground recce
7.0 CONCLUSIONS
Today over half of the world’s population is concentrated in urban
areas covering just 4 % of the world’s surface. Mega cities in particular arecharacterized by a high population density and tremendous pressure on
supporting infrastructure, leading to increased vulnerability of the society tonatural disasters, if and when they occur. This calls for prior preparation by
the authorities and governing agencies by performing the safety assessmentof the existing infrastructure. The Landslide Hazard Zonation and
Avalanche Modeler as described in this paper are useful tools for theplanners and decision makers in analyzing the disaster susceptibility ofurban growth extending into hazard prone regions. Nevertheless theaccuracy of these estimates can be enhanced by correlating with the grounddata collected during reconnaissance surveys.
The implementing of modern GIS technology for developing hazard
zonation maps taking into account the spatial variation of mountainous
terrain has so far been unexplored in India and hence needs immediate
attention.

Safety Assessment of Existing Road in the Himalayas using GIS and Satellite Imagery
534

19

October 2004, Agra, IndiaACKNOWLEDGEMENTS
The authors are grateful to Dr. R. N. Sarwade, Director, Snow &Avalanche Study Establishment (SASE), Manali, for granting thepermission to publish this paper. Our profound sense of gratitude also to Col.
P. Mathur, Deputy Director, SASE and Lt. Col. R. S. Puri, Assistant
Director, SASE, for their numerous valuable suggestions andencouragement.
REFERENCES
Comfort, L. K., 1999. The impact of information technology upon disastermitigation and management. Proceedings of the Second Conference on
the Applications of Remote Sensing and GIS for Disaster Management,
Washington D.C., CD-ROM.
Gamba, P., and Casciati, F., 1998. GIS and image understanding for nearreal-time earthquake damage assessment. Photogrammetric Engineering& Remote Sensing, Vol. 64, 10, 987-994.
Nagarajan, R., Mukherjee, A., Roy, A., and Khire, M. V., 1998. Temporal
remote sensing data and GIS application in landslide hazard zonation ofpart of Western Ghat, India. International Journal of Remote Sensing,Vol. 19, 4, 573-585.
Raju, R., and Saibaba, J., 1999. Landslide hazard zonation mapping using
remote sensing and geographic information system. IEEE 1999
International Geoscience and Remote Sensing Symposium, Hamburg,
CD-ROM.
Sharma, S. S., and Ganju, A., 2000. Complexities of avalanche forecastingin Western Himalaya: an overview. Cold Regions Science andTechnology, 31 (2000) 95-102, 96-100.
Shikada, M., Suzuki, Y., Kusaka, T., and Goto, S., 1997. An application of
GIS information and remotely sensed data for extraction of landslide.
IEEE 1997 International Geoscience and Remote Sensing Symposium,
Singapore, CD-ROM.
Van Westen, C. J., 1994. GIS in landslide hazard zonation: a review with
examples from the Andes of Columbia. In Price, M. F., and Heywood, D.
I. (editors), Mountain Environment and Geographic Information
Systems, Taylor & Francis, London, 135-166.
Verstappen, H. T., 1995. Aerospace technology and natural disaster
reduction. In Singh, R. P., and Furrer, R. (editors), Natural Hazards:
Monitoring and Assessment using Remote Sensing Technique, Elsevier
Science, Inc., New York, 3-15.
Vincent, R. K., 1997. Fundamentals of geological and environmental
remote sensing. Prentice-Hall, Inc., Upper Saddle River, NJ.
Yuan, R. K. S. and Mohd., M. I. M. (1997). Integration of remote sensing
and GIS techniques for landside applications. Proceedings of Asian
Conferenceon
RemoteSensing(ACRS)
1997.http://www.gisdevelopment.net/aars/acrs/1997/ps3/ps3006pf.htm

20

New Technologies for Urban Safety of Mega Cities in Asia
535