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EGU Journal Logos (RGB) O O O p p p Advances in e Annales e Nonlinear Processes e n n n A A A Geosciencesc Geophysicaec in Geophysicsc c c c e e e s s s s s s Nat. HazardsEarthSyst. Sci.,13,505–522,2013 Natural Hazards O Natural Hazards O p p wdowi:w10.n.5at1-9h4a/znahrdesss-e-1a3rt-h5-0s5y-s2t-0s1c3i.net/13/505/2013/ and Earth System en Ac and Earth System en Ac c c ©Author(s)2013. CCAttribution3.0License. Sciencese Sciencese s s s s Discussions Atmospheric O Atmospheric O p p e e n n Chemistry A Chemistry A c c c c and Physicse and Physicse s s s s 19 May 2011 Ku¨tahya – Simav earthquake and evaluation of Discussions existing sample RC buildings according to the TECA-tm20o0sp7hcerriict eOpria Atmospheric Op e e n n Measurement A Measurement A c c M.H.Arslan1,M.Olgun1,M.A.Ko¨rogˇlu2,I.H.Erkan1,A.Ko¨ken1,andO.Tan1 Techniquesce Techniquesce s s s s 1DepartmentofCivilEngineering,SelcukUniversity,42075Konya,Turkey Discussions 2DepartmentofCivilEngineering,NecmettinErbakanUniversity,42060Konya,Turkey O O p p Correspondenceto:M.H.Arslan([email protected]) en Biogeosciencesen Biogeosciences A A c c c Discussions c Received:19October2012–PublishedinNat.HazardsEarthSyst.Sci.Discuss.:– e e s s s s Revised:25December2012–Accepted:3January2013–Published:25February2013 O O p Climate p Abstract. This study examines the damage caused to rein- 7.2))(ArslanandKorkmaz,2007;CC¸algi˘mataay,t2e0 0e5;Ineletal., e n n forced concrete structures by the 2011 earthquake that oc- 2008; Tan et al., 2008; Adalier and Aydıngu¨n, A2001; Sezen of the Past A of the Pastc c c c curred in Simav, Turkey. The study briefly reports on post- et al., 2003; Dog˘angu¨n, 2004; Celep et al., 201e1; Kaplan et e s Discussionss s s earthquakefield observations,tectoniccharacteristics ofthe al.,2004).Themajorityofthesestudiesarerelatedtobuild- earthquakearea,geotechnicalcharacteristicsofthefield,and ingswithreinforcedconcrete(RC)structuralsystems.How- seismic characteristics of the earthquake. The main part of ever,mostofthelow-riseresidentialbuildingscOponstructedin Earth System Op thestudycomprisesafieldstudy,materialexperiments,and villagesandsmalltownsEaraemrtahso Snryyssttruecmtur eens.Therefore, en A Dynamics A performance analyses of two reinforced concrete buildings much of the knowledge aboutDTuyrnkiashmeaircthsqucake hazards, c c c thatsurvivedtheearthquakewithmediumleveldamage.The structuraldeficiencies,anderrorsareconcentratesedonRCand Discussionses s s building performance was calculated and assessed accord- masonry structures (Arslan and Korkmaz, 2007; C¸ag˘atay, ing to the Turkish Earthquake Code requirements for exist- 2005;Ineletal.,2008;Kaltakcıetal.,2007;Tanetal.,2008; Geoscientific Geoscientific ing building stock, and recommendations were made based AdalierandAydıngu¨n,2001;Sezenetal.,2003O;Dog˘angu¨n, O p p onthefindings. 2004;Celepetal.,2011;InKsaptrlaunmetealn.,t2a0t0io4;nA erslan,2010). Instrumentation e n n On 19 May 2011 an eaMrthequthakoedwsi tahnmdag Acnitude (Mw) Methods and Ac c c 5.7 occurred in Simav, in Ku¨tahya Province, leocated in the e Data Systemsss Data Systemsss western part of Turkey. According to the Earthquake De- 1 Introduction partmentoftheDisasterandEmergencyManagementPresi- Discussions dency(DEMP),theearthquakeoccurredat20:O15localtime GeoscientificO Turkey is situated in an active earthquake zone and more with epicenter coordinatesGoefo39s.1c3i2e8n◦Nti,fi2c9.pe0820◦E at a pe n n than 90% of its land area is within highly seismic re- depthof24.46km.Theearthquakeresultedin2 Afatalitiesand Model Development A Model Developmentc c gions. During the 20th century, Turkey experienced sev- morethan122injuries.Approximately2500afcetershocksoc- ce s Discussionss eral moderate to heavy earthquakes that resulted in signif- curred after the main shock (Sandıkkaya et als., 2011; ˙Inel s icant loss of life and property, and 22 major earthquakes et al., 2011; Kaplan et al., 2011), with a magnitude range with minimum magnitudes 7 (Mw) caused significant ca- (ML)ofbetween1.3andH4y.8d(Sroanldoıkgkyay aaentdal .,Op2011).After Hydrology and Op smuaazlt,ie2s00a7n;dC¸eaxgt˘eantasyiv,e20st0r5u;ctIunrealledtaaml.a,g2e0(0A8)r.slTanheanlidteKraoturkre- tihneg ethaerthcqauuasekseoTfutrhkeishdarmEesaeagaerrscthhoen rSsefsyopcseuctsieaeldmlyoRnen AcCunbdueirlsdtianngds-. Earth Systemen Ac includes many studies of earthquakes and post-earthquake Tama(2012)investigatedthebuSildcinigesnbcyeP2s5-cesrapidassess- Sciencesces case studies in Turkey because several destructive earth- mentmethod.Themethodshowedthattwoofsthebuildings s Discussions quakes have hit the country during the last two decades were in “high risk band”; the other two fell into “detailed (including1992Erzincan(Mw=6.8),1996Adana–Ceyhan evaluation band”, and the rest were in the “lowOprisk band”. Op (Mw=6.3),1999Adapazari–Izmit(Mw=7.4),1999Du¨zce So his findings demonstrated that the figure menatched with Ocean Scienceen (Mw=7.2),2002Afyon–Sultandagi(Mw=6.5),2003Bin- thedamagesobservedOintcheesaitne sSurvceiyeanftcereth Acceearthquake. Discussions Acc gol (M =6.4), 2010 Elazıg˘ (M =6.0), 2011 Van (M = e e w w w s s s s PublishedbyCopernicusPublicationsonbehalfoftheEuropeanGeosciencesUnion. O O p p e Solid Earthe n n Solid Earth A A cc Discussions cc e e s s s s O O p p e The Cryospheree n n The Cryosphere A A c c c Discussions c e e s s s s Fig. 1. 506 M.H.Arslanetal.: 19May2011Ku¨tahya Fig. 1. Fig. 2. Fig.2.MajorfaultingsystemintheSimavregion(AFAD,2011). Fig.1.Majortectonicelementsan ddistributioninTurkey(Adalier andAydingun,2001). Fig. 2. Province (EAF), the Aegean Graben System, the Cyprus– This study briefly examined structural damage caused by HellenicArc,theCentralAnatolianProvince,andtheBlack this earthquake event. The seismic characteristics of the Sea region (Sengor et al., 19 85). The tectonics of Turkey earthquakeweredeterminedbyexaminingtheseismicstruc- is greatly influenced by the movements of the Arabian, ture and soil features of the region. Soil and material ex- Eurasian, and African plates (Fig. 1). The Arabian plate perimentsrequiredbyTurkishEarthquakeCode(TEC-2007) moves NE and pushes the Eurasian plate along the Bitlis normsweremadeintwolow-risebuildingsthatex perienced thrustandfaultzone.Duetothiscontinuingmovementofthe medium damage. Using the obtained data, the load systems Arabianplate,theAnatolianblockshiftswestwardalongthe ofthebuildingswereevaluatedtoanalyzestructuralperfor- NorthandNortheastAnatolianfaults.Ontheotherhand,the mance. The main aim of the study is to compare two sam- African plate moves in the NE direction, colliding with the 32 ple RC buildings located on alluvial soils, which suffered Eurasianplate,andsubductsalongtheCyprus–HellenicArc, damagebutremainedstanding,andtocriticallyevaluatethe somewhat retarding the westward movement of the Anato- provisions of the TEC-2007 regulations. For this purpose, lianblockandinitiatingitstendencytorotatetotheSW.The the seismic performance of the selected buildings obtained interaction of these complex plate motions resulted in sev- by the non-linear evaluation procedures given in TEC-2007 eralE–Wtrendingblocksboundedbyobliquenormalfaults has been conducted. Global pe rformance of these buildings insouthwestTurkey.Consequently,thisregioncoveringthe wasdeterminedfromthemem berperformancesandthean- Cyprus-Hellenic Arc and the Aegean Graben System has alyticalresultswerecomparedwiththeexperienceddamage veryhighseismicity(Konak,1982). ofthebuildings.Aftertheasse ssmentacriticalcomparative The Aegean region of Turkey, including Ku¨tahya evaluationhasbeendonefromtheobtainedresults. Province, is a highly active seismic area and has frequently been exposed to earthquakes. Ku¨tahya is affected by the groundmotionsresultingfromtheGediz–Emet,Simav,and 2 Seismicityandgeotechnicalcharacteristics Ku¨tahya fault lines. Throughout history many destructive earthquakes causing loss of life and property have occurred 2.1 Tectonicsetting in the region (Table 1). The highest magnitude earthquake recorded in this region was generated by the Gediz fault in Turkey is located in the eastern Mediterranean segment on March 1970 and resulted in more than 1000 casualties and theAlpine–Himalayanearthqu akebeltandisfrequentlyex- the total collapse of 3500 buildings. The most recent disas- posedtodestructiveearthquakes.Accordingtotheseismicity trousearthquakeofKu¨tahya–Simavin2011,approximately   32 mapofTurkey,95%ofthepopulationand92%ofTurkish 40kmfromtheepicenterofthe1970Gedizearthquake,led land is within seismically active areas (on seismic zones 1 toconsiderabledamageinSimav,Ku¨tahya. to4).TheKu¨tahya–Simavregionisinthefirstseismiczone Simav district is located within a collapsed basin (ele- according to the seismic zoning map of Turkey and has a vation 800m) known as the Simav Graben. Simav Moun- seismiccoefficientof0.4gaccordingtoTEC-2007. tain extends east–west and is located in the south of Simav. There are seven major tectonic provinces in Turkey: The most important tectonic feature of the study area is the North Anatolian Fault (NAF), the Northeast Ana- Simav Fault, an active right strike-slip fault extending ap- tolian Fault (NEAF), the East Anatolian Contractional proximately 205km length in a general NW–SE direction Nat. HazardsEarthSyst. Sci.,13,505–522,2013 www.nat-hazards-earth-syst-sci.net/13/505/2013/ M.H.Arslanetal.: 19May2011Ku¨tahya 507 Fig. 3. Fig. 3. Table 1. Recent destructive earthquakes in the Aegean region of Turkey. Date InstrumentalMagnitude Epicenter 1928 6.2 Emet 1944 6.2 Saphane 1970 7.2 Gediz 1970 5.9 Cavdarhisar 2011 5.7 Simav (Konak, 1982; Sarog˘lu et al., 1987, 1992). The epicenter of the 19 May 2011 Simav earthquake was the Simav Fault Zone. The region includes active fault segments within the SimavfaultzonewithaNW–SEdirection(Fig.2).Withinthe month following the earthquake, 1629 aftershocks occurred aroundtheSimavepicenter.Themagnitudesofmostofthese Fig.3.Simplifiedgeologicalmap ofSimavanditsvicinity(Inelet aftershocks (1322) were 3 or less (M≤3). The number of al.,2011). Fig. 4. seismogramsoftheearthquakeswhosemagnitudeswerebe- Fig. 4. tween3and4(3<M≤4)was292,andthenumberofseis- mograms of the ones between 4 and 5 (4<M≤5) was 13 (Fig.2). 2.2 Geologicalsetting The Ku¨tahya–Simav region is characterized by plateaus of varying heights, with some mountains and hills as well as largeplains.Bothmountainandhillrangesandlowareasare oriented in NW–SE direction, which is consistent with the generalcharacteristicsoftheregion.TheKu¨tahya,Tavs¸anlı, Altıntas¸, Gediz, Simav, and O¨rencik plains, which are allu- viumcovered,formthelowerpartsofthisregion.Themain part of the region consists of Neogene plateaus. Within the study region, the Neogene series begins with a thick con- glomerateseriesandcontinueswithclay,marl,andlimestone Fig.4.Spectralaccelerationvalues forfourearthquakesinTurkey. series. Despite generally being horizontal, Neogene series aresometimessloping.Theregionhasmanyblockfaultsas aresultoftheseNeogeneseries.Tectonicactivitiesaregen- Thisclayedsedimentisupto1 0mthickinsomeplaces,and erallyobservedinthewestandsouthwestoftheregion.Old hashighplasticityandlowbearingcapacity. Neogeneterrestrialsedimentsareobservedinthesoutheast- ern, northern, and northwestern parts of Simav district. In 2.3 Characteristicsofstrongmotionrecords addition, pre-Neogene basic rock units of various ages can befoundacrossawidearea.Thelandisgenerallyroughex- The highest acceleration value of the earthquake was mea- cept in the northern part of Simav and has many valleys of sured as 103.92cms−2 (gal) i n an E–W direction in Gediz varying sizes. These valleys are generally filled with young district. As a result of a study based on the 31-km distance alluviumcarriedbyrivers. fromtheGedizstationtoSimav,Ineletal.(2011)predicted TheplaininthenorthernpartofSimavdistrictinvolvesal- thegroundaccelerationinanE– Wdirectionas247cms−2at luvialmaterialwithhighgroundwaterlevel,andthesouthern theepicenter. Spectrumvaluesina N–S directionarelower partinvolvesrock(limestoneandschist)andslopewashma- than those in an E–W directio n. Maximum ground acceler- terials (Fig. 3). Until 1960 Simav Lake extended northwest ationpredictedinTEC-2007forthisregionis392.4cms−2. from Simav city center; after 1960, this lake was dried by Figure 4 shows spectral accele ration with respect to the pe- openingchannels,leavingblack–darkgreyorganicclay.Af- riodforadampingratioof5% .Itisinferredthattheearth- ter drying the lake, the site was zoned for co nstruction, and quake impacted structures wit h a fundamental period of up 33 now includes a dense residential area and public buildings. to0.15s. www.nat-hazards-earth-syst-sci.net/13/505/2013/ Nat. HazardsEarth Syst. Sci.,13,505–522,2013   33 508 M.H.Arslanetal.: 19May2011Ku¨tahya 3 Damagetypesinreinforcedconcretestructures ThetypicalconstructionsinTurkeyareRCmoment-resisting frames with hollow, unreinforced clay-brick infill panels as theurbanpartofthisarea.Crackfailuresandcollapseofin- fill walls, resulting in significant economic loss and human casualties,areobservedonRCstructures.Mostofthedam- agetosuchstructuresoccurredinlocationswithalluvialsoil. TheclaysoilsinthenorthernpartofSimavbearnegative geotechnicalconditions.Soilamplificationishigherinthese types of soil during an earthquake. In addition, soil softens under continuous loads in these types of soils and shearing resistance parameters (cohesion and angle of internal fric- tion)decrease.Whenthesitesofstructuraldamageareexam- ined,itcanbeseenthattheeffectoftheearthquakeextended to an area of approximately 25km radius from the epicen- terandthereislessstructuraldamageintheareawith10km radius(redring)(Fig.5).Oneofthemainreasonswhysignif- Fig.5.DistributionofdamagedareasinandaroundSimav(Inelet icantdamageswerenotobservedinsettlementareassuchas al.,2011). S¸enko¨y, So¨g˘u¨t, and Kapıkaya even though they are close to theepicenteroftheearthquake,isthatstructuresarelocated onunitswithtighterandmorerigidgeotechnicalfeatures. 2.4 GeotechnicalaspectofSimavearthquake In Simav city center, inadequate spacing between neigh- boring buildings contributed to serious damage to a signifi- Significant amounts of damage were observed in buildings cant number of buildings. During the earthquake, hammer- locatedonclayedunitswithyounglacustrinesediment,even ing(structurescontactedeachotherduetodifferencesinthe though they were located away from the epicenter. These dynamic properties of adjacent buildings) was observed in regions cover especially the northern part of the center of many neighboring buildings. Similar to previous studies of Simav.Instandardpenetrationtests(SPT)conductedinthese earthquakes in Turkey (Adalier and Aydıngu¨n, 2001; Sezen clayunits,generalaverageN valuesrangedbetween7and 30 et al., 2003; Dog˘angu¨n, 2004; Celep et al., 2011; Kaplan et 13(Ineletal.,2011).Consideringthesevalues,theunitcan al.,2004),post-earthquakeobservationsrevealedpoordetail- beclassifiedasCorDsoilgroupaccordingtodisasterregu- ing,andalackofappropriatereinforcementwasobservedin lations.Acceptingthattheunitthicknessdoesnotgenerally manyRCframedstructuresinSimav.Thewideshearcracks exceed15meters,territorialsoilclassfallswithintheZ2–Z3 and plastic hinging at column ends indicate that poor de- interval. In addition, in some regions with low construction tailing and an insufficient number of column transverse re- density,astheclayunitthicknessexceeds10–15m,theterri- inforcements led to catastrophic failure. In Simav a lack of torialsoilclassisZ3–Z4.Shearwavevelocity(V )measured s inthislevelisaround250ms−1.Duetothesefeatures,high stirrupsatthejointswasobserved,makingthebeam-column joints vulnerable to earthquakes (Sandıkkaya et al., 2011; soilamplificationvaluesareobservedinthesesettlementar- ˙Inel et al., 2011; Kaplan et al., 2011). The major deficien- eas. ciesofreinforcementdetailinginSimavareasfollows: Many urban and rural settlements, especially in the cen- ter of Simav, have been settled in graben (sediment) areas. Moreover,thesesettlementareasarelocatedinlacustrineal- luvial soil units with high groundwater levels. This geolog- Unsuitable transverse reinforcement (large spacing of ical structure in settlement areas has become a basic con- stirrups(Fig.6a)andlackof135degreehooksattheend trolfactorintermsoftheeffectsofearthquakesonbuildings. ofcolumnties) When the damage distribution in the district was examined, more damage was observed in the structures located on al- Duringanearthquake,someadditionallateralforcesarein- luvial soil (plains) compared to those on rock fields in the duced in a structure. These loads increases the shear forces south.However,theobservationsshowednoadvancedlique- on the structures, so, actually for columns, design of the factioninSimavplaininthisearthquakeevent. shearreinforcementisessential.Widespacingoflateralties isacommonshortcomingobservedinSimavRCstructures. During site observations after earthquakes, it is noted that thestirrupspacingwasmuchmorethanthemaximumvalue allowed by the design code TEC 2007. For most of the damaged columns, no tie spacing of less than 100mm was Nat. HazardsEarthSyst. Sci.,13,505–522,2013 www.nat-hazards-earth-syst-sci.net/13/505/2013/ M.H.Arslanetal.: 19May2011Ku¨tahya 509 observed. Often unequally spaced ties are between 150mm Insufficientlateraltiesatthebeam–columnjoints and300mm. For TEC-2007, “hoops and crossties used in columns, Wide spacing of lateral ties is a common shortcoming ob- beam-column joints, wall end zones and beam confinement served by authors in Turkish RC structures. During site ob- zones of all reinforced concrete systems of high ductility servationsafterearthquakes,itisnotedthatthestirrupspac- level or normal ductility level in all seismic zones shall be ingwasmuchmorethanthemaximumvalueallowedbythe specialseismichoopsandspecialseismiccrossties”.Special design code (Sandıkkaya et al., 2011; ˙Inel, 2011; Kaplan et seismic hoops shall always have 135degree hooks at both al.,2011),asseeninFig.6a.Inmostdamagedcolumns,atie ends. 90-degree hook does not provide effective anchorage spacingoflessthan100mmwasnotobserved. since it is not embedded in the confined. Unfortunately, in Simav,90-degreehookshavebeencommonlyobserved. Using plain rebar for reinforcement (low tensile quality ofsteelreinforcement)(Fig.9a) Unconfinedlapsplices After the earthquakes, especially widespread use of plain- The strength of the lap splice is very important for the de- rebarcausedbondproblemscoupledwithinsufficientsplic- velopmentofstrengthandductilityofareinforcedconcrete inglengthshavebeenobservedinmanyRCbuildings. column.Accordingtotheobservationinthefield,lapsplices In addition to reinforcement detailing deficiencies, low insubstandardcolumnsweretypicallydesignedascompres- qualityconcretecausedadherenceproblemsinRCmembers, sion splices with the lap length of about 20 to 24 times bar resultinginplastichinging. diameter.Thereasonformostobserveddefectsindamaged Tallerfirststoriesanddisuseofwallsforexteriorcladding, members is because of unconfined lap splices, inadequate inordertousethefirstfloorsasshopsbecauseofhighresi- anchorage lengths (15–30cm), and lower longitudinal rein- dentialdensitiesinSimavcenter,causedweakandsoftstory forcementratiosthanconsideredindesign.Alsolapsplices problems. The building in Fig. 6b collapsed as the moment of a column longitudinal reinforcement should be made, as frame was both flexible and weak in the first story com- much as possible, within the column central zone. Accord- paredwiththeupperstories.Deformationsareconcentrated ingtoTEC2007,lapsplicesinmoment-framecolumnswere inthefirststoryofthisbuildingsincethefrontofthebuild- typically made immediately above the floor framing or the ingwasopenedonthefirststory.Thefirst-storycolumnsin foundation.So,lapsplicesincolumnswerelocatedinaplas- thisbuildingwereseverelydamagedandleanedontothead- tichingezonewhichisthemostcriticalpartofRCmembers. jacentbuilding.Softstoryfailuresoccurinbuildingsdueto thesuddenchangeofstorystiffnesswithopenfrontsonthe groundfloorortallgroundstory(excessivestoryheightwith Inadequateanchoragelengths respecttoothers).Themostcommonexamplesareshopping malls,offices,andhotels,etc. Thecompositeactionofconcreteandsteelinreinforcedcon- Because the length of the columns is less, as seen in crete structures is provided by bond strength. The required Fig. 6c, the column becomes stiffer, more rigid in bending bond strength is achieved by providing sufficient develop- andreceiveshighershearforceduringanearthquake.Since ment length. In Turkish Building Code (TS-500-2000) and themomentarmisshort,theshearforcesincrease.Theshort TEC-2007minimumdevelopmentlengthl isgiven. p column problem occurred due to the arrangement of infill Lackofanchorageofbeamsandinsufficientsplicelengths walls due to window openings in the base floor. In TEC- is secondarily affected by low-quality levels of concrete. 2007, where shear force short columns cannot be avoided, Damage due to poor quality of material was reported in the very stringent requirements for transverse reinforcement of earthquake. shortcolumnsareputforward,whicharetakenintoaccount for the design of transverse reinforcement of columns. Fig- Lowerlongitudinalreinforcementratiosthanconsidered ure6cisagoodexampleofthiskindofshortcolumndamage indesign(Fig.6a) fromSimavEarthquake. Thelongitudinalrebarratio(ρ )rangesbetween1%and4% 1 4 AshortdescriptionofsurveyedRCbuildings in TEC-2007. In TEC-2007, to increase the ductility, low intheregion steel ratio is encouraged because it is an amplification of a larger cross section. In the earthquake zone, Fig. 9a shows More than thirty government buildings were surveyed in thecolumnswithbuckledlongitudinalbarsbecauseoflower Ku¨tahyacitycenteranditsdistrictsbyauthors.Surveyteams reinforcementratioandlackofstirrups. have conducted necessary measurements and took adequate concretesamplesandcarriedoutdestructiveaswellasnon- destructive tests to obtain member sizes, member detailing www.nat-hazards-earth-syst-sci.net/13/505/2013/ Nat. HazardsEarthSyst. Sci.,13,505–522,2013 Fig.5. Fig. 7. 510 M.H.Arslanetal.: 19May2011Ku¨tahya Fig. 6. a- Lack of stirrups at b- Failure on first floor c- Short column failure the joints due to soft story Fig.6.Threedamagetypesfromepicenterregion. Fig. 8. Fig. 7. Fig.8.Buildingfacadeandlateral facade(casestudy1).   34 Fig.7.Geographicaldistributionsofthebuildingsstudied. Fig. 8. proximately6.76MPa.Itiswo rthnotingthatthecurrentcode TEC-2007requiresaminimumof20MPaforthedesignof buildings. From visual inspect ion, it has been observed that andthemechanicalpropertiesofthematerials.Asindicated generally plain bars with a characteristic yield strength of later,atleastthreecoresamplesperstoryweretakentode- nearly220MPawereused. termine the building-specific concrete compressive strength Themajorityofthesurveyed buildings’structuralsystems tobeusedintheperformanceanalysis. weremadeofRCwithvaryingpercentagesinthecolumnand Allbuildingshaddifferentconstructiondates,numbersof shear wall area. Since the density of shear walls in a given stories, and flat areas given in Table 2. The damages in the principal direction is believed to have a prominent role in buildings were classified into four ranks during the investi- theseismicperformanceofthebuildings(ArslanandKork- gation given in Table 2: (1) light and no damage; (2) mi-   maz,2007;C¸ag˘atay,2005;Ineletal.,2008;Tanetal.,2008; 35 nor damage; (3) medium damage; (4) major damage. Ge- AdalierandAydıngu¨n,2001;Sezenetal.,2003;Dog˘angu¨n, ographical distributions of the buildings studied are shown 2004; Celep et al., 2011; Kaplan et al., 2004), it is not sur- andmarkedinFig.7.Itisclearlyseenthatallbuildingsare prising to observe that most of the buildings have no shear locatedintheearthquakeregion. walls. Distribution of concrete compressive strength shown in Table 2 reveals that the concrete compressive strength was generallybetween4.9–18.2MPawithanaveragevalueofa p- Nat. HazardsEarthSyst. Sci .,13,505–522,2013 www.nat-hazards-earth-syst-sci.net/13/505/2013/   35 M.H.Arslanetal.: 19May2011Ku¨tahya 511 Table2.Descriptionofgovernmentbuildingssurveyedbytheteam. Location Construction Construction Numberof Stories Totalarea Numberof Averagecompression Steel Damage type date story area coresamples resistanceof rebartype type coresamples(MPa) KCC RC 1994 5 1097 5485 15 6.3 S220 1 KCC RC 1988 3 188 564 9 11.7 S220 1 KCC RC 1987 5 160 800 15 4.85 S220 1 KCC M 1968 3 145 435 – – – 1 KCC RC 1991 1 263 263 4 9.9 S220 1 KCC M 1957 2 329 658 – – – 1 KCC RC 1975 1 525 525 3 4.8 S220 1 KCC RC 2003 1 616 616 3 18.2 S420 1 Gediz RC 2003 3 300 900 9 12.5 S420 1 Gediz RC 1977 4 120 480 12 5.1 S220 1 Gediz RC 1992 2 300 600 6 4.9 S220 2 Tavs¸anlı RC 1994 5 550 2750 15 8.5 S220 2 Tavs¸anlı RC 1988 5 320 1600 15 7.2 S220 1 Tavs¸anlı RC 1978 3 150 450 9 5.6 S220 1 Tavs¸anlı RC 2000 1 360 360 3 6.4 S220 1 Tavs¸anlı RC 1997 1 174 174 3 8.2 S220 1 Tavs¸anlı RC 1997 2 177 354 3 7.1 S220 1 Emet RC 1986 5 340 1700 18 5.4 S220 1 Simav RC 2008 4 342 1368 12 18.2 S420 1 Simav M 1951 2 216 432 – – – 1 Altıntas¸ RC 1994 2 340 680 6 6.8 S220 2 Domanic¸ RC 1997 2 280 560 6 6.2 S220 1 Hisarcık RC 1999 2 280 560 6 6.4 S220 2 Pazarlar M 1962 1 216 216 – – – 1 Aslanapa RC 2009 2 228 456 6 15.1 S420 1 Dumlupınar M 1987 2 149 298 – – – 1 C¸avdarhisar RC 1996 3 262 540 15 7.9 S220 1 Dumlupınar M 1970 2 160 320 – – – 3 Simav-Case1 RC 1990 5 515 2574 15 8.1 S220 3–4 Simav-Case2 RC 1997 6 282 1696 18 6.7 S220 3–4 Yoncalı M 1993 1 800 800 – – – 2 KCC:KutahyaCityCenter,RC:ReinforcedConcrete,M:Masonry Fig. 9. 5 SeismicperformanceassessmentofRCbuildings accordingtoTEC-2007 Within seismic codes, the earthquake safety of exist- ing RC buildings is determined based on the concept of performance-based design. Generally this takes the form of the desired performance outcomes, such as withstanding minor earthquakes undamaged, withstanding medium-scale earthquakes with limited damage, and withstanding large- scale earthquakes without total collapse. The critical out- come is prevention of total structural collapse. This means that the upper level withstands total collapse (CP); the sub level,forthecrucialstructures,maybeslightlydamagedbut remains fit for immediate occupancy (IO). Between the sub and upper levels there is a life safety (LS) level situation. Multiple performance objectives for these levels, including the seismic transformation periods, have been specified in Fig.9.Filledwalldamage. Table3. Fig. 10. In Turkey two main codes influence the design and con- struction of RC buildings: TEC-2007 and TBC-500-2000. designofcolumn,beam,andshearwallelements.TheTBC TECincludesproceduresforcalculatingearthquakeloadson includes requirements for the design and detailing of RC buildingsanddeterminingearthquakeperformanceofexist- components but does not include ductile detailing require- ing structures. This code includes specifications for ductile mentsforuseinseismicdesign. www.nat-hazards-earth-syst-sci.net/13/505/2013/ Nat. HazardsEarthSyst. Sci.,13,505–522,2013   36 512 M.H.Arslanetal.: 19May2011Ku¨tahya Table3.StructureperformancebasedondamageinTurkishEarth- seismic performance of buildings can be determined using quakeCode(TEC-2007). linear or non-linear analysis; the design engineer is free to utilizeeitherlinearornon-linearanalysisapproaches.Short Performance Performancecriteria procedure seismic performance assessment of an RC build- level inginTEC-2007isgivenbelow: Immediate 1. Collecting data from existing RC building (structural occupancy(IO) – The ratio of beams in layout,planandverticaldimensions,numberofstories Slight Damage (SD) and andarchitecturalfeaturessuchassoftandweakstories Moderate Damage (MD) and overhangs, short column formations etc., obtained shall not exceed 10% in anystory. concrete average compressive strength, steel yield strength,steeltype,stirrupsspacingintheconfinement – There must not be any regions,identificationofsoiltype). columns beyond Slight Damage(SD). – There must not be any 2. 3-Dmodelingbyusingobtaineddatafromtheexisting beams beyond Heavy RCbuilding. Damage(HD). 3. Performanceanalysisaccordingtotheselectedmethods LifeSafety (Linearornon-linear)inthecode. (LS) – The ratio of beams in Moderate Damage (MD) andHeavyDamage(HD) 4. JudgingtheperformanceofexistingRCbuildings. shall not exceed 30% in anystory. – In any story, the shear 5.1 Non-linearseismicperformanceassessment force carried by columns inTEC-2007 in Heavy Damage (HD) shall not exceed 20% of The purpose of the non-linear analysis methods is to deter- storyshear. minethestructuralperformanceofexistingRCbuildingsun- der seismic loading. In TEC-2007, the earthquake safety of Collapse existingRCbuildingsisdeterminedbasedonaperformance- Prevention – The ratio of beams in based design. The non-linear evaluation method considers (CP) Heavy Damage (HD) the elasto-plastic behavior of the structural system and the must not exceed 20% in mainapplicationprocedureisincrementalequivalentseismic anystory. analysisaccordingtothesinglemode. – In any story, the shear The objective is to carry out the non-linear static analy- force carried by column sisunderincrementallyincreasingseismicforces,distributed that passed Slight Dam- in accordance with the dominant mode shape in the earth- age(SD)mustnotexceed quakedisplacement,untildemandisreached.Internalmem- 30%ofstoryshearforce. berforcesandplasticdeformationsarecalculatedatthede- mand level. After the plastic rotation demands of ductile Collapse members are calculated, these values are compared and de- (C) – If the failure can not be finedinTable4. prevented,itisunderfail- Theseismicperformanceoftheload-bearingsystemisde- urecondition. finedasthesumofseismicdamagelevelsofthestructuralel- ements(e.g.,beamsandcolumns)thatformtheload-bearing system. As part of the static pushover analysis, it is neces- sarytodefinethecross-sectionaldamagelevelaccordingto the deformation of each of the structural elements in order When a short history of earthquake codes is considered, todeterminetheglobalperformanceoftheload-bearingsys- the earthquakes in Turkey and the code revisions occur at tem. Table 4 shows cross-sectional damage types according similar times. The recently published version of the TEC- toTEC-2007. 2007 includes seismic performance evaluation and seismic TEC2007definestheperformancelimitsofdeformations retrofitting sections that are parallel to those in FEMA-356 ofRCelementsasmaximumunitdeformations,calculatedin andFEMA-440.LikeFEMA-356,TEC-2007statesthatthe concreteandrebarinthesection.Limitvaluesgiveninunit Nat. HazardsEarthSyst. Sci.,13,505–522,2013 www.nat-hazards-earth-syst-sci.net/13/505/2013/ Fig. 9. M.H.Arslanetal.: 19May2011Ku¨tahya 513 Table4.Cross-sectionaldamagelevels. Cross-sectionaldamagelevel Maximumstrainforconcrete(εc) Maximumstrainforsteel(εs) SlightDamage(SD) 0.0035 0.010 (cid:16) (cid:17) ModerateDamage(MD)* 0.0035+0.01 ρs ≤0.0135 0.040 ρsm (cid:16) (cid:17) HeavyDamage(HD)** 0.004+0.014 ρs ≤0.018 0.060 ρsm ∗and∗∗:Deformationvaluesintheouterfiberofthestirrup. Fig. 10. deformation terms were defined in terms of plastic bending by using moment-bending relationships calculated primar- ily for the section. The plastic bend value is determined ac- cordingtowhetherconcreteorsteelfiberreachestheabove- mentioned limit values first. The plastic bend value is then multiplied by the plastic hinge length (L =0.5h) given in p TEC-2007 in order to obtain plastic bending. In the equa- tion given in Table 4, ρ is the volume ratio of minimum sm transversereinforcementintheconfinementzone,calculated accordingtoTEC-2007[13];ρ isthevolumeratiooftrans- s versereinforcementintheexistingsection. Pre-yieldlinearbehaviorofreinforcedconcretesectionis representedbycrackedsections,whichis0.4EI forflexural o members(suchasbeams),andvariesbetween0.40–0.80EI o foraxialloadedcolumns.Intheanalyses,strainhardeningin theplastichingerangecanbeignored. Fig.10.Filledwalldamage. 6 Casestudies were 30cm×50cm, 50cm× 60cm, 30cm×55cm, and 25cm×50cm rectangular sections. RC shear wall existed Thesamplebuildingshavebeenselectedfromthesurveyed only in the elevator shaft in lead system. Beams were 20 buildingsintheregion.Thesamplebuildingsthathavebeen cm×60cm and 25cm×60cm. Story heights were 3.00m explainedindetailwerethebestexamplesoftheirstructural in the basement, 4.00m in the ground story, 2.25m in the typeamongthemorethanthirtybuildings.Thebuildingsde- installationstoryand3.20min eachtypicalstory. signed and constructed before the TEC-1998 seismic code Non-loadpartitionwallswereparticularlybadlydamaged havesimilarstructuraldeficienciesobservedaftertheearth- in the earthquake. Partition walls were separated from the quake in Turkey. The structural system and the geometry of these buildings are thought to represent the current RC frame due to both in-plane a nd out-of-plane movements. Damagewasespeciallyseverearoundthewallsofsubfloors structural stock of Turkey. The sample buildings have been (Figs. 9 and 10). The architec t of the project removed sig- markedinboldinTable2. nificant parts of the ground story walls due to the projected 6.1 Casestudy1 usage of the building even though the project originally in- cludedthem. 6.1.1 Briefdescriptionoftheselectedexis ting Diagonal fractures occurred in significant parts of the in- 36 RCbuildings filled walls through the dissipation of energy. Therefore, no significant damage was observed in load-bearing elements The building used as case study 1 is located in the Simav (column,beam,etc.).Inaddition,theribbonwindowsofthe district of Ku¨tahya Province. It comprises 5 stories: 1 base- basementstoryintherearfacadeofthebuildingcausedshear ment, 1 ground story, 1 installation story, and 2 typical sto- cracks in upper bearings of columns (short column mecha- ries. The building was constructed in 1990. The facade of nism).Figure11showstheappearanceofshortcolumnform- the building is shown in Fig. 8. The load-bearing system of ing. thebuildingwasplannedasareinforcedconcreteframe.The Unsupervisedconstructionandevendesignfactorsareim- floor system of the building was beam slab with slab thick- portantcausesofdamageintherelevantbuilding(andother ness of 12cm. In situ measurements of columns, which are governmentbuildingsinSimavdistrict)sustainedduringthe the vertical bearing elements, determined that the columns earthquake. The examinations indicated frequent mistakes www.nat-hazards-earth-syst-sci.net/13/505/2013/ Nat. HazardsEarthSyst. Sci.,13,505–522,2013 Fig. 11. Fig. 12. 514 M.H.Arslanetal.: 19May2011Ku¨tahya Fig. 11. Fig. 11. Fig. 13. Fig.11.Shear-columndamage.   Fig.13.Obtainedcoresamples. 37 Fig. 12. Fig. 12. building.Aftercompletingthegeneralgeometricalsurveyto determinethecharacteristicsoftheas-builtproject,adetailed experimental program was planned. This program includes on-site destructive testing and laboratory tests on the speci- mens(coremembers)obtainedfromthestructuralelements, in order to evaluate the mechanical properties of concrete materials (Fig. 13). The experiments were conducted in the Earthquake and Construction Laboratory of Selcuk Univer- sity. Average concrete compression resistance of the build- ing was found to be 8.1MPa (f =81kgcm−2). The com- c pressivestrengthsofthecoremembersaregiveninTable5. Observations made during the search-and-rescue phase and core-removal works at the site suggested that the quality of theconcreteusedwasextremelyinsufficient.Examinationof theconcretecoresamplesobtainedfromthebuildingfound Fig.12.Utilizedrebar(beamFF-ciioggl.u. m1133n..n odeofgroundstory). that the concrete aggregates had been used in their natural states without being washed and sieved, and the grain size distributionwasnotsuitableforahighqualityconcrete. thatcannotbeexplainedwithprinciplesofRCconstruction. The class of steel rebar used in the building was S220 Thebasiccausesofdamagearedefectsintheplacementand (fy =220MPa).Therebarsintheloadsystemelementswere themechanicalcharacteristicsoftransverseandlongitudinal locatedusingarebardetectiondevice;thenumberanddiam- rebar, low concrete quality, inappropriate wall construction, etersofrebarsweredetermined,andaccuraterebardistribu- andtheincreasedheightandlowrigidityofthegroundstory tion was recorded in the model. It was found that confine- compared to other floors. The beam-column connection re- mentintervalsincolumnsandbeamswereabout17–25cm. gion shown in Fig. 12 demonstrates that the building is far Theexaminationsdeterminedthatthevertical(longitudinal) from complying with the provisions of TEC-2007. There is rebarratioincolumnswasapproximately0.8%–1.0%. no stirrup in the column and beam connection region, stir- Soil core samples showed that the territorial soil class is rups hooks have 90degree angles, there is hooking in the Z3,whichissimilartoclassCsoilinFEMA-356.TEC-2007 compression rebar, and the distance between rebars is non- specifiesspectrumcharacteristicperiodsas0.15sand0.60s compliant. inthistypeofsoil.ThebuildingislocatedonQuaternaryold alluvial,whichisclassifiedasclayeysand(SC;USCSclassi- 6.1.2 Seismicperformanceassessmentaccording ficationsystem).SPTnumberN30inthesoilgenerallyranges   toTEC-2007 between7an3d730.Inafieldwherethedepthoftheground-   37 waterlevelisbetween4.5and7.0m,topographicinclination TheevaluationsaccordingtotheTEC-2007normsprimarily isabout0–5%.AccordingtoTEC-2007,inafieldwheresoil determined on-site values of the load-bearing system of the classisCandterritorialsoilclassisZ3,groundwaterlevelis Nat. HazardsEarthSyst. Sci.,13,505–522,2013 www.nat-hazards-earth-syst-sci.net/13/505/2013/

Description:
existing sample RC buildings according to the TEC-2007 criteria. M. H. Arslan1 . the Alpine–Himalayan earthquake belt and is frequently ex- posed to Hellenic Arc, the Central Anatolian Province, and the Black. Sea region .. usage of the building even though the project originally in- cluded them
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