印尼抗震规范英文版

1SEISMICRESISTANTDESIGNSTANDARDFORBUILDINGSTRUCTURESSNI–1726–2002*)By:Prof.WiratmanWangsadinataChairmanSNI-1726-2002CommitteeABSTRACTInthispaperthemainprinciplesoftheSeismicResistantDesignStandardforBuildingStructuresSNI-1726-2002areexplained.TheDesignEarthquakeconsideredhasareturnperiodof500yearsandtheresultingpeakbaserockaccelerationformsthebasisforestablishingtheIndonesianSeismicZoningMap.Thepeakgroundaccelerationdependsonthesoilcategorypresentontopofthebaserock.WiththisaccelerationtheresponsespectraoftheDesignEarthquakearedefinedfordeterminingtheeffectoftheDesignEarthquakeuponbuildingstructures.UndertheeffectoftheDesignEarthquakethebuildingstructureisatitsstateofnearcollapsewithamaximumdeflection,assumedtobethesameforanyductilitylevelofthestructure.Withthisassumptionandknownoverstrengthinthestructure,foracertainlevelofductility,asimpleformulationisestablishedregardingtheeffectoftheDesignEarthquakeuponabuildingstructure,suchaselasticload,maximumloadonthestructureatitsstateofnearcollapse,firstyieldloadandnominalloadfordesign.AgainsttheeffectoftheDesignEarthquake,abuildingstructureisingeneralanalyseddynamicallyusingresponsespectrummodalanalysismethod.However,regularbuildingstructures,havingtheirfirstandsecondmodemotiondominantlyintranslation,maybeanalysedstaticallyusingequivalentstaticseismicloads.Thesubstructure(basementandfoundation)maybeanalysedasaseparatestructuresubjectedtotheeffectoftheDesignEarthquakeoriginatingfromthesuperstructure,fromowninertialforcesandfromthesurroundingsoil.FinallythestrengthdesignofthesubstructurebasedontheLoadandResistanceFactorDesignmethodisdiscussed.Keywords:Standard,earthquake,dynamicresponse,structure,building,ductility.1.INTRODUCTIONThisstandardhastakenintoaccountasfaraspossiblethelatestdevelopmentofearthquakeengineeringintheworld,particularlywhathasbeenreportedbytheNationalEarthquakeHazardsReductionProgram(NEHRP),USA,initsreporttitled“NEHRPRecommendedProvisionsforSeismicRegulationsforNewBuildingsandOtherStructures”(February1998),butontheotherhandmaintainsascloseaspossibletheformatofthepreviousstandard“RulesforEarthquakeResistantDesignofHousesandBuildings”(SNI03-1726-1989).Ingeneralthisstandardissufficienttobeusedasthebasisforthemoderndesignofnewseismicresistantbuildingstructures,particularlyhighrisebuildings.Modification,alterationandadjustmentofvariousprovisionsareexpectedtobe*)PresentedattheInternationalCourseonSustainableStructuralSafetyDesignforBuildingEngineers,organizedbytheMinistryofHousing&RegionalInfrastructureincooperationwithJapanInternationalCooperationAgency,Jakarta–Bandung–Bali,Indonesia,1–31July20022necessary,afterobtainingrealexperienceintheirapplicationinpractice,alsoasaconsequenceofthecontinuousadvancementsinthefieldofearthquakeengineeringitself.Inorderthatthebuildingengineeringcommunityunderstandswhatthebasicprinciplesareofthisstandard,inthispapertheirbackgroundareexplained.Moredetailedexplanationscanbefoundinthecommentaryoftherespectiveclauses,whichisanintegralpartofthestandard.2.DESIGNEARTHQUAKEANDSEISMICZONINGMAPOFINDONESIAAnearthquakeisanaturalphenomenaintheformoflocalgroundmotiongeneratedbytectonicmovementsoftheearth’scrust,itsoccurrencebeingprobabilistic.Thismeansthatifacertainperiodoftimeisconsidered,theprobabilityofoccurrenceofmildearthquakesishigherthanoflargeearthquakesduringthatperiod.Inotherwords,mildearthquakeshavearelativelyshortreturnperiod,whilestrongearthquakesarelativelylongone.Fortheseismicresistantdesignofbuildingstructures,accordingtothisstandardaDesignEarthquakecausinglocalgroundmotionwithareturnperiodof500yearsmustbeconsidered.Accordingtotheprobabilitytheorem,suchanearthquakehasaprobabilityofoccurrenceof10%inaperiodof50years.Thisperiodof50yearsisassumedtobethelifetimeofnormalbuildingswithnoparticularimportance.Thelocalgroundmotionasthebasisfortheseismicresistantdesignofbuildingstructures,isgenerallyexpressedinthepeakgroundacceleration.Thismotionistheresultofseismicwavespropagatingfromthebaserocklocatedbelowthesurface.Whilepropagating,thewavesundergoamplifications.Thesofterthesoillayersareontopofthebaserock,thegreatertheamplification.Conversely,theharderthesoillayersareontopofthebaserock,thesmallertheamplification.Todeterminethelocalgroundmotionwithareturnperiodof500yearscausedbytheDesignEarthquake,aprobabilisticseismichazardanalysismustbeconducted.Fromtheresultofsuchananalysispeakbaseaccelerationswithareturnperiodof500yearsatnumerouslocationsthroughoutIndonesiahavebeenobtained.Thus,onthemapofIndonesiacontourlines,showingpointswithequalpeakbaseaccelerationwithareturnperiodof500years,havebeendrawn.Basedonsuchacontourlinemap,theSeismicZoningMapofIndonesiahasbeenestablishedasshowninFigure1.Theseismotectonicinputdatafortheprobabilisticseismichazardanalysisconsistof:earthquakesourceareas;magnitudefrequencydistributionattheearthquakesourceareas;attenuationfunction,relatinglocalpeakbaseacceleration,earthquakemagnitudeatthefocusanddistancefromthefocustothesite;minimumandmaximummagnitudeatthesourceareas;annualfrequencyofoccurrenceofearthq