ICUS NEWSLETTER

ICUS NEWSLETTERInternational Center for Urban Safety Engineering

Institute of Industrial Science

The University of Tokyo

VOLUME 5 NUMBER 3OCTOBER-DECEMBER 2005

FROM GROUND SHOCKS TO AIR BLASTS:MULTIPLE-HAZARDS PROTECTION OF BUILDINGS

By

TSO-CHIEN PAN *

Map of epicenter

Reflecting the rapid economicgrowth and development, manyhigh-rise buildings and complexinfrastructure systems have beenconstructed in recent decades inalmost all Mega Cities of Asia. Ofconcern is the high concentrationof population and commercialactivities taking place in thesecities. Therefore, the consequencesof even a moderate disaster may be

enormous in these cities. Recenttechnological development hasmotivated the devising of newmethodologies for sustainabledevelopment of Asian Mega Citieswith adequate safety and security.The importance of using advancedtools in urban safety has beenrecognized by the InternationalCen te r fo r Urban Sa fe tyEngineering (ICUS). This is the

motivation for ICUS to organize aseries of symposium in the AsianReg ion . These sympos iumsencourage trilateral communicationamong researchers, practitionersand policy- makers, whereby theepicenter of this is evidently humanlives. Any improvement of urbansafety serves to better protect thecore of a community – humanlives.

International Center for

Urban Safety Engineering

Republic Plaza

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ICUS Newsletter Vol. 5, No. 3

damage assessment of buildingssubjected to ground shocks; and (c)blast response of buildings.

FAR-FIELD EARTHQUAKEMOTIONS

Singapore is located in a lowseismicity region of Sunda plate.The Suma t r an f au l t and t heSumatran subduction zone, arelocated more than 350 km away.While earthquakes have neverposed any rea l p roblems fo rS ingapo re , p r ev ious l a rgeearthquakes have induced tremorsfelt in Singapore. Like other megacities, the lack of free surface landhas prompted the construction oftaller buildings. These taller andflexible buildings may respondmore significantly to long period,f a r- f i e ld ea r thquake g roundmotions.

On 26 December 2004, theGreat Sumatra-Andaman IslandsEarthquake (Mw = 9.0) occurredoff the northwest coast of Sumatra,Indonesia. The epicenter of thisearthquake is about 916 km west-northwest from Singapore (figurein previous page).

Since 1996, one of the tallestbu i ld ings in S ingapore , t heRepublic Plaza shown in previouspage has been instrumented tostudy buildings responses due towinds and far-field earthquakes.The Republic Plaza is a 66-storey,280 m high tower consisting of aframe-tube structural system with acentral core wall, in turn connectedto a ring of external columns by ahorizontal steel framing system atevery floor. From ambient vibrationtests, the predominant frequenciesof the building are found to be 0.19Hz and 0 .20 Hz , i n the twohorizontal directions.

The Four th In t e r na t iona lSymposium on New Technologiesfor Urban Safety of Mega Cities inAsia (USMCA 2005) was held inNanyang Technological University,Singapore, during October 18-19,2005. I t was co-organized byProtective Technology ResearchCenter, Nanyang TechnologicalUniversity, Singapore, and ICUS,IIS, University of Tokyo, Japan.About 100 par t ic ipants f romvarious countries were present. Thecountries included Austral ia,Thailand, Bangladesh, China, Japanand Singapore. The participantsincluded engineering researchers,defence scientists, design engineersand members o f gover nmentorganizations. The variation of theparticipant’s background supportsthe philosophy of ICUS’s intent forthese sympos iums . For th i ssymposium, the areas discussedi n c l u d e s a f e t y a s s e s s m e n tand mon i to r ing o f ex i s t inginfrastructure, threat reductionand consequence management,structures subjected to seismic,shock and impac t l oads ,environmental impact assessmentof urbanization, tsunamis, flood andenvironmental risk assessments.During the symposium, the two co-chairmen of the symposium, Prof.Kimiro Meguro and Prof. Pan Tso-Chien, were interviewed by theChannel News Asia TelevisionStation. During the interview, boththe co-chairmen emphasized theneed for the balance betweenengineering solutions and theenforcement of these solutions.

Within the Singapore com-munity, the concerns about urbansafety include: (a) the response ofbuildings subjected to far-f ieldearthquake ground motions; (b)

Accelerometers are installed atthe basement level and the rooflevel, along the two principledirections of the building. Theacce le romete rs recorded thebuilding vibration during the GreatSumat ra -Andaman I s l andsearthquake. The ground signalsrecorded at the basement were usedas the input to the finite elementmodel of the Republic Plaza. Whensubjected to this input groundmot ion , the response resu l t sob ta ined numer ica l ly werecompared wi th the r eco rdedresponses shown in above figure.At the roof level, the displacementresponse obtained by the numericalmethod is reasonably similar to thatof the recorded response.

GROUND SHOCKSMost mega cities have limited

free space. Singapore’s nationaleffort is to intensify its land use.This has prompted under-groundspace development, leading to thehousing of ammunition storagesunderground. As a result, groundshocks due to acc iden ta lunderground explosions and theireffects on surrounding buildingsare investigated.

Ground shock characteristicscan be segmented into two parts:the major shock duration (Phase 1)and the ensuing duration (Phase 2).I t was shown tha t t he h ighfrequency nature of a ground shockleads to a large shear force withsmall deformation during Phase 1,f o l l owe d b y s i g n i f i c a n tdeformation during Phase 2. InPhase 2, the responses of globalmodes are signif icant, and thiswould poss ibly cause beam-column joint failure.

Numerically determined displacement compared with recorded displacement

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For non-seismically designedbeam-column sub-assemblies, ithas been experimentally observedthat the beam-column joints mayfail at an inter-storey drift ratio ofabout 3 % of the storey height.

A non-seismically designed 6-storey reinforced concrete (RC)frame was subjected to a simulatedground shock. For the simulatedground shock, the peak groundacceleration (PGA) is 124 gal, thepeak particle velocity (PPV) is 0.9m/s and principal frequency isabout 200 Hz. By considering thefailure mechanisms of flexuralfailure (FF), diagonal shear failure(SF) and joint failure (JF), thedamage for the 6-storey RC framesubjected to the simulate groundshock was assessed.

A pa rame t r i c s t udy wasundertaken which involved thescaling of the PGA, PPV andp r inc ipa l f r equency o f t hesimulated ground shock. The

distance, the dynamic deformationwas localized at the blastloadedcolumns spanning the first and thethird storeys. The beams connectedwith these columns might thusbe damaged . La rge r e s idua ldeformations were observed forthe blast-loaded columns and thebeams connected to them. Thus,the beams connected to thesecolumns might be damaged asshown in the figure.

Compared with the case of longstandoff dis tance, the globalresponse hardly existed in theshor t s tandoff dis tance case.Furthermore, compared with thecase of long standoff distance, thedamage in the case of short stand-off distance was more localized.

CONCLUSIONSIn summary, there is a need to

investigate systematically theeffects of multiple hazards whichmay include both natural and man-made events. In this article, themultiple hazards investigatedcomprised the effects of long-distance major Sumatra earth-quakes, ground shocks, and airblasts. The dynamic response ofthe non-seismically designedbuilding structures in Singapore tothese multiple hazards has shownvarying characteristics.

This will pose a challenge tothe engineering community whomust strike a balance betweensafety and economy in designingand cons t r uc t i ng a bu i l d ingstructure to resist multiple hazards.The consequences f rom anyextreme event of multiple hazardscould be devastating to mega-citiesdue to the high concentration ofpopulation and also the high-valueof commercia l and f inancia lactivities. However, it is importantto realize that the dynamic effectsof these events have varyingcharacteristics and frequency ofoccurrence.

* Director, Protective TechnologyResearch Centre, Nanyang

Technological University,Singapore

characteristics of the scaled groundshock leading to the various failuremechanisms, are shown in theabove Figure.

AIR BLASTSEffects of an air blast explosion

on a high-rise commercial RCbuilding resulting from a vehiclebomb at the ground level area,were investigated. The objectivewas to investigate the effect ofstandoff distance on buildingdamage. The high-rise commercialbuilding selected for the study wasa 30-storey RC structure withframes and a shear wall core.

For a long standoff distancecase , t he de fo r ma t ion wasconcentrated at the ground columnand the beams of the second andthe t h i rd s t o r eys . The beamdeformation was focused at itsends whe re l oca l damagesoccurred like as the figure below.

However, for a short standoff

Stresses and deformation forshort standoff

Damage characteristics of a 6-storey RC frame to ground shocks

Stresses and deformation forlong standoff

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by Center for Sustainable UrbanRegeneration, The University of Tokyo,21st Century Center of ExcellenceProgram, Ministry of Home Affairs(Singapore), Shimizu Corporation,CPG Corporation Pte Ltd. and SurbanaInternational Consultants Pte Ltd..

Seven keynote papers and 63technical papers were presented. 97delegates from 12 countriesparticipated in the symposium.

This symposium provided aplatform for sharing knowledge andforming a network among the Asianresearchers. The number ofparticipants are increasing and thequality of papers are improving ateach new symposium. The nextsymposium will be held at Phuket,Thailand on December 16-17, 2006.Further details will be announced soon.

(by H.Kanada)


On October 18-19, 4th Interna-tional Symposium on New Technolo-gies for Urban Safety of Mega Cities inAsia was held at Nanyang ExecutiveCentre, Nanyang TechnologicalUniversity, Singapore. The symposiumwas co-organized by ICUS andProtective Technology Research Centre,School of Civil and EnvironmentalEngineering, Nanyang TechnologicalUniversity, Singapore, and sponsored

Symposium participants pose for a group photo

4th International Symposium on New Technologies forUrban Safety of Mega Cities in Asia at NTU, Singapore

Number of participants per country

Number of presentation

ICUS PARTICIPA-

RNUS SeminarOn October 20, RNUS organized

another RNUS seminar on ‘AdvancedTechnology for Urban Safety – AgainstDisaster and Hazardous Environment’.Four professors from the University ofTokyo were invited to give thepresentation. The presenters were Prof.T. Uomoto, Prof. R. Amano, Prof. K.Meguro,and AssociateProf.R.Ooka.

The content of this seminar coverstechnologies applicable to preventvarious types of disaster and toevaluate hazardous environmentalcondition. There were approximately80 audiences in this seminar. Not onlystaffs and students of AIT but thosefrom other institutes and engineersfrom construction companies alsojoined this event.

Field Trip to New AirportRNUS held the field trip to the

new internat ional airport of

Thailand on October19,2005.Thename of this new airport wereconferred by H.M. the King asSuvarnabhumi or“GoldenLand”

Dr.Tokuda:Chief of Thai Obaya-shi Corp in Suvarnabhumi Airport

RNUS Activities

Prof.W. Kanok-Nukulchai gavea present to Prof. T. Uomoto

on September 29, 2000 and afoundation stone laying ceremonywas held on January19,2002.

The field trip which was led byDr. Tokuda began with a briefintroduction about the airportconstruction and ended with a visitto the construction of runways andterminals.

Suvarnabhumi airport has anapproximate area of 8,000 acres andis located around 25 km to the eastfrom the downtown Bangkok.

There are two 60-m wide parallelrunways (4,000 and 3,700 m.respectively). Two parallel taxiwayswere designed to accommodatesimultaneous departures andarrivals. The annual passengercapacity is expected to be 45 millionat opening day and 100 million uponattaining the full capacity.

(by R. Sahamitmongkol)

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On October 8, 2005, at 3:50(UTC), a magnitude 7.6 earthquake,with a focal depth of 26 km, struck theNorth of Pakistan and North West ofIndia. Most damaged area is NorthWestern Frontier Province (NWFP),and Azad Jammu and Kashmir (AJK)in Pakistan. Many cities, towns andvillages were heavily damaged.

The s ta t i s t ics of humancasualties and structural damage areprovided in the following tables. Dueto this earthquake, approximately75,000 people and 77,000 were killedand injured, respectively. Mainly alltypes of masonry structures weredamaged during this earthquake.

This earthquake occurred in amountainous area like the 2004 Mid-

Temporary heliport set at dry riverbed(Alai)

Niigata Prefecture Earthquake, Japan.So the geo-related damage waswidespread. Many roads were brokenand damaged. Therefore, manypeople living in mountainous areawere isolated and could not evacuateand get foods and tents. Militarycarried affected people to refugeecamps or medica l centers byhelicopters. They made temporaryheliports at riverbeds and fields andused them.

One of the features of thisearthquake damage was that publicbuildings, especially school buildingshad heavy damage near the epicenter.So many students and teachers wereaffected (see upper right table). School

buildings located not near theepicenter had also cracks in the walls.As the earthquake occurred duringschool time, students ran away fromclassrooms without their textbook,bags etc. After the earthquake, thestudents did not return to the schoolsdue to three reasons: “Students do notwant to come to school”; “Theirparents do not send them to school”;and “Teachers do not want to go toschool”. So it is necessary to providepsychological support to both studentsand teachers and construct emergencybuilding for schools.

(by Shinya Kondo, Researcher of Disaster Reduction

and Human RenovationInstitution)

Pakistan and India was Struckby a M 7.6 Earthquake on October 8, 2005

Map of Damaged Area(UN OCHA Relief Web)

Casualties in Pakistan and India(as of November 20, 2005by UN OCHA Relief Web)

Damaged buildings in Pakistan(as of November 20, 2005by UN OCHA Relief Web)

Casualties at schools in AJK,Pakistan (as of November 20,

2005 by UN OCHA Relief Web)

Damaged school buildings in AJK,Pakistan (as of November 20, 2005

by UN OCHA Relief Web)

Many large land slides were observed(Muzaffarabad)

Many public buildings were collapsed(Muzaffarabad)

Due to fear of earthquake, both students and teachers dislike attendingschool even if the structural damage were not so severe (Mansehra)

Pancake collapse of building(Abbottabad)

A year has passed since the hugetsunami generated by a M9.0earthquake off Sumatra devastatedIndian Ocean rim countries. Thenumber of victims by this event wasreported as over 300,000. However,the number is still unconfirmed evenafter one year due to lack of properidentity check and a large number ofdead bodies being carried away byhuge waves. Affected countries areseeking a reasonable approach toimprove their preparedness againsttsunami disaster to avoid the sameconsequence in the future.

Most straightforward approachfor tsunami disaster reductionwould be setting back from the coastline. However, it is not always anacceptable solution for everyone.

As shown in photos , theirlivelihood is inseparably linked toocean. Beach front location whichallows guests good access to waterpleasure, nice ocean view andcomfortable sound of waves is anindispensable factor for resort hotels.Fishers tend to live just next toshore line. They use beach as adock to maintain fishing boats andequipments, an yard to process thecatch and meeting space withneighbors for f ishers. With thisreality, tsunami warning system(TWS) can be a most practicalsolution.

Meguro Lab., IIS, The Universityof Tokyo has proposed a sustainable

TWS concept using Multi-PurposeObservat ion Buoy Network.Important characteristics of thissystem are its simplicity, economicalefficiency and daily-usability. IndianOcean rim countries have lessresource of technologies, researchersand experiences of tsunami disasterscompared with Pacific Ocean rimcountries. So, it is important formonitoring tsunami which occurs inaround 100-year period continuouslywithout any interruptions to developa scheme to use and maintain themonitoring system on daily basis.Industries inherent in coastal areahave strong need to collect variouskinds of information as shown inmiddle figure above.Promotion ofcoastal industries and continuoustsunami monitor ing can beaccomplished by adding tsunamimonitoring function on the systemcollecting daily use information.

Minimum unit of the system isone or two multi-purpose observationbuoys operated by one beachsociety. The cost to maintain thesystem should be shared by the beach

society, who will receive the mostbenefit from the system. When manybeach societies install the system andjoin the multi-purpose observationbuoy network beyond theadministrative or internationalboundary, it must be possible togather marine information neededon daily basis in much larger scaleand to get more advantage beforetsunami arrival even in case oftransoceanic tsunami.

Understanding and cooperationof local leading industries andgovernments are essent ia l toimplement this kind of plan. Wehad opportunities to talk with resorthotel owners, managers and localgovernment officers in our f ieldsurveys. It was found that hotelowners and managers who did notreceive physical damage on theirproper t ies but suffered f romdecline of guests with harmfulrumors tends to have a stronginterests on our concept. We wishto implement our concept incooperat ion wi th those localstakeholders and contribute to thetsunami disaster safety in theircountries.

For further information: seeICUS Report, Report on the 2004Sumatra Earthquake and TsunamiDisaster, 2005- 01.

(by Masasuke Takashima,Lecturer of FujiTokoha University)

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Potential of Coastal Industry in Tsunami Disaster Reduction

ICUS PARTICIPA-

Inter Maintech 2005 was heldfrom November 15 to 18 at TokyoInternational Exhibition Center. This isthe only trade show in Japan whichfocuses on diagnosis and repair as wellas maintenance related managementtechnology from industrial facilities tosocial-capital infrastructure relatedfacilities such as concrete and steelstructures.

ICUS set up booth and presentedthe following research topics;1. Diagnosis software for concrete

structures (concrete bridges, piled

piers, tunnels)2. Development of new technique to

detect deleterious substances ofconcrete using NIR spectral imagingsystem

INTER MAINTECH 2005

Networked MultipurposeBuoy System

left: resort beach in PhiphiIs., Thailand right: a fishing village in Trincomalee, Sri Lanka

Concept of Sustainable TsunamiWarning System using Multi-

Purpose Maritime Observation

Booth of ICUS

3. Online monitoring system for agingconcrete bridgesOver 400 specialists visited our

booth and were interested in exhibits.Various publications from ICUS werealso distributed there. Stock ran out dueto heavy demand of ICUS publications.

ICUS will make a presentation atThe 10 Earthquake Technology EXPOscheduled to take place at PACIFICOYOKOHAMA from February 2 to 3,2006.Please come and visit our booth.

(by H. Kanada)

ICUS New Staff

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The Institute of Industrial Science(IIS) of the University of Tokyoorganized an open house at its ChibaExperiment Station on November 11,2005. There were 651 participants inthis event.

ICUS also participated in thisevent and presented its researchactivities. The ICUS topic was“Towards Safety Improvement inMega Cities.” Research associate ofICUS, Dr. Endo guided andexplained the research works to the

participants.Elementary school students

from near the experiment stationvisited the facilities. They listenedto Dr. Endo intently. They attendedand drew picture on concrete blockat the Uomoto laboratory.

Professor Uomoto, the head ofChiba Experiment Station gave aspecial lecture on “Urban Safety onConcrete.”

(by R. Ooka)

ICUS is glad to welcome its newstaff, Dr. Raktipong Sahamitmongkolwho joined ICUS as Researcher fromOctober 1st, 2005.

He received his Ph.D degree fromthe school of civil engineering, theUniversity of Tokyo in September,2005. During his doctoral study, healso got the outstanding presentationaward at the annual meetings of JapanConcrete Institute (JCI) and JapanSociety of Civil Engineering (JSCE).His research interests are the usage ofexpansive agent to prevent crackingor to control cracking condition inRC structure.

In his research, it was found thatthe expansive additive with suitable

reinforcement not only inducesbeforehand the compressive stress inconcrete, but it can also enhance theductile behavior of concrete. As aresult, the cracking of RC structure canbe effectively prevented. Thistechnique is proved advantageous to

elongate the service life of importantinfrastructure.

He has been assigned to station atthe Regional Network for UrbanSafety (RNUS) which locates in theAsian Institute of Technology (AIT),Thailand to activate morecollaborative research with other Thaiorganizations.

Recently, he started more researchprogram including the study about theapplication of ferrocement to protectthe structural element in buildingfrom bomb blasting, bridge inspectionin Bangkok Metropolitan Area, andthe application of NDT to inspect thecondition of concrete structure.

(by T. Uomoto)Dr. Raktipong Sahamitmongkol

• Project team was formed toconsider the role of The Universityof Tokyo Hospital in a time ofdisaster. The joint working groupmeetings are regularly convened.

• All ICUS members participated inthe 4th International Symposiumon New Technologies for UrbanSafety of Mega Cities in Asia atNTU, Singapore (Oct 18-19).

• Second student seminar was heldand 25 students in ICUS reportedtheir current research results(Dec 9).

• Prof. Uomoto attended RNUSSeminar at AIT (Oct 20-21) and13th general meeting and workingof ISO/TC71 in Seoul (Nov 27-30).

• Prof. Amano attended RNUS

Seminar at AIT (Oct 20-21).• Prof. Meguro attended RNUS

Seminar at AIT (Oct 20-21), WorldSeismic Safety Initiative boardmeeting in Singapore and visitedIslamabad to investigate thedamage due to northern Pakistanearthquake (Oct 22-Nov 1).

• Dr. Ooka attended RNUS Seminarat AIT (Oct 20-21), InternationalSymposium on SustainableDevelopment o f As ia Ci tyEnvironment 2005 in China (Nov23-27).

• Dr. Oki attended The Second Post-GAME Planning Workshop inThailand (Nov 4-7) and The SecondPost-GAME Planning Meeting inThailand (Nov 19- 24).

ICUS Activities

Awards

• Dr. Kato stayed at Asian Instituteof Technology for his researchwork and teaching duties atRNUS (Sep 19-Dec 9) andat tended a conference onDurabi l i ty o f ReinforcedConcrete under CombinedMechanical and Climatic Loadsin China (Oct 26-31) and visitedVietnam Institute for BuildingScience & Technology toexchange views (Nov 10-13).

• Dr. Yoshimura attended RNUSSeminar at AIT (Oct 20-21).

• Dr. Sahamitmongkol stayed atAsian Institute of Technology forhis research work and teachingduties at RNUS (Oct 5- Dec 18).

Open Campus of IIS Chiba Experiment Station

Three graduate students; D. Itoh,T. Nanjyo (Meguro lab.) and N.

Takeshita (Kato lab.) won theexcellent presentation award at 60th

annual meeting of Japan Society ofCivil Engineers (Dec 26).

Guidance by Dr. Endo

Special lecture by Prof. Uomoto

page 8

Such news were never reported inJapan until now. The person, whobought the houses paying a largeamount of money, lost everythingexcept the loan which was lent to himby the banks. If such a disaster iscaused by the natural hazards(earthquake, tsunami, flood, fire, etc.),people and Japanese government maytry to help the victims by all means.But in this faked design case, it maynot be easy to request the people ofour country to support the victims.

The systems now being used in ourcountry are all based on Japaneseculture and ethics that people will not

try to do things bad, unless by accident.But this news gave us a big warning toour culture: Ethics is no longerefficient and “Learning makes a goodman better and an ill man worse” (Seethe above figure). “Safety” is nowbecoming one of the most importantrequirements in urban area, and ICUShas been working to prevent andreduce the natural disasters for morethan 5 years. May be we at ICUS haveto widen our researches to man madedisasters, not only natural hazards andterrorism but also to the faked workswhich have not been exposed yet.

(by T.Uomoto)

International Center for Urban Safety Engineering, ICUSInstitute of Industrial Science, The University of Tokyo4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, JapanTel: (+81-3)5452-6472, Fax: (+81-3)5452-6476E-mail:[email protected]://icus.iis.u-tokyo.ac.jp/

Editor’s Note

In November 2005, a big shockstruck Japanese society throughnewspapers, radio and TV. Mr.Hidetsugu Aneha, a first-classcertified architect confessed that hefaked records to make substandardbuildings look like they met Japan'santi-earthquake requirements. In thecommittee of Japanese parliament,he mentioned that he began fakingearthquake safety data around 1998,when a developer asked him toreduce costs by decreasing theamount of steel reinforcements belowthe compulsory minimum in a Tokyoapartment project. He mentionedthat he was under heavy pressurefrom the developer to reduce steelreinforcements. Initially he refusedthe request because of his pride as afirst-class certified architect. Butconsidering the reduction inconstruction cost and pressure fromthe developer, altimately hesuccumbed. The newspapersmentioned that at leat 88 structures(as of December 28, 2005) which hehas designed may collapse in amoderate earthquake tremor.

PRINTED MATTER

International Center for

Urban Safety Engineering

Keio Presso Inn, Gotandahas been closed for demolitiondue to lack of adequateearthquake resistance

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