文献翻译静力弹塑性分析法在侧向荷载分布方式下的评估研究.docx
- 文档编号:7035724
- 上传时间:2023-01-16
- 格式:DOCX
- 页数:10
- 大小:30.02KB
文献翻译静力弹塑性分析法在侧向荷载分布方式下的评估研究.docx
《文献翻译静力弹塑性分析法在侧向荷载分布方式下的评估研究.docx》由会员分享,可在线阅读,更多相关《文献翻译静力弹塑性分析法在侧向荷载分布方式下的评估研究.docx(10页珍藏版)》请在冰豆网上搜索。
文献翻译静力弹塑性分析法在侧向荷载分布方式下的评估研究
EVALUATIONOFLATERALLOADPATTERN
INPUSHOVERANALYSIS
ArmaganKORKMAZ1,AliSARI2
1VisitorResearcher,DepartmentofCivilEngineering,UniversityofTexasatAustin,Austin,TX78712,PH:
512-232-9216;armagan@mail.utexas.edu
2Ph.D.Student,DepartmentofCivilEngineering,UniversityofTexasatAustin,Austin,TX78712,PH:
512-232-9216;ali_sari@mail.utexas.edu
ABSTRACT
Theobjectiveofthisstudyistoevaluatetheperformanceoftheframestructuresorvariousloadpatternsandvarietyofnaturalperiodsbyperformingpushoverandnonlineardynamictimehistoryanalyses.Theloaddistributionsforpushoveranalysesarechosenastriangular,IBC(k=2)andrectangular.Fourdifferentframedstructuresareused,whicharetypicalreinforcedconcrete(R\C)framesystemsandhavefourdifferentnaturalperiods.EventhoughthenonlineardynamictimehistoryanalysisisthebestwaytocomputeseismicdemandsFEMA-273andATC-40proposestouseofnonlinearstaticprocedureorpushoveranalysis.Thispaperisalsointendedtocomparetheresultsofpushoverandnonlineardynamictimehistoryanalyses.Toevaluatetheresultsfromthepushoveranalysesforthreeloadpatternsandalsofournaturalperiods,nonlineardynamictimehistoryanalysesareperformed.Earthquakegroundmotionsrecordedat50stationsduringvariousearthquakesoveralltheworldareusedintheanalyses.Pushoverandnonlineartimehistoryanalysesresultsarecomparedtochoosethebestloaddistributionforspecificnaturalperiodforthistypeofframestructure.
Keywords:
Pushoveranalysis,nonlineartimehistory,loadpatterns,moment-resistingframe
INTRODUCTION
Onlythelifesafetyandcollapsepreventioningeneralearthquakeresistantdesignphenomenaareexplicitlypreventedinseismicdesigncodes.Thedesignisgenerallybasedonevaluatingtheseismicperformanceofstructures.Itisrequiredtoconsiderinelasticbehaviorwhileevaluatingtheseismicdemandsatlowperformancelevels.FEMA-273andATC-40usepushoveranalysisasnonlinearstaticanalysisbutnonlineartimehistoryanalysishasmoreaccurateresultsoncomputingseismicdemands(ATC-40,1996,FEMA-273,1997).Thepurposesinearthquake-resistancedesignare:
(a)topreventnon-structuraldamageinminorearthquakes,whichmayoccurfrequentlyinlifetime,(b)topreventstructuraldamageandminimizenon-structuraldamageinmoderateearthquakeswhichmayoccuroccasionally,(c)topreventcollapsingorseriousdamageinmajorearthquakeswhichmayoccurrarely.Designsareexplicitlydoneonlyunderthethirdcondition.
Theobjectiveofthisstudyistoevaluatetheperformanceoftheframestructuresforvariousloadpatternsandvarietyofnaturalperiodsbyperformingpushoverandnonlineardynamictimehistoryanalyses.3,5,8and15storyR\Cframestructuresareusedintheanalysesandtheloaddistributionsforpushoveranalysesarechosenastriangular(IBC,k=1),IBC(k=2)andrectangular,wherekistheanexponentrelatedtothestructureperiodtodefineverticaldistributionfactor(IBC,2000).ThefourframestructureshavebeenanalyzedusingnonlinearprogramDRAIN-2D(Prakash,V.,Powell,G.,Campbell,S.,1993)andtheresultshavebeencomparedbyrecordedresponsedata.Bothnonlinearstaticpushoveranalysisandnonlineardynamictimehistoryanalysisareperformed.Thecorrelationsbetweenthesenonlinearanalysesarestudied.
Theperformanceofthebuildingssubjectedtovariousrepresentativeearthquakegroundmotionsisexamined.Finally,pushoverandnonlineartimehistoryanalysesresultsarecomparedtochoosethebestloaddistribution(pattern)forspecificnaturalperiodforthesetypesofreinforcedconcreteframestructures.
GROUNDMOTIONDATA
Forthisstudy,itisconsideredas50differentdatausedinthenonlineardynamictimehistoryanalyses,givenintheTable1.AllthedataarefromdifferentsiteclassesasA,B,CandD.TheshearvelocitiesforthesiteclassesA,B,CandDareVs>750m/s,360m/sto750m/s,180m/sto360m/s,and180m/s,respectively.Thegroundmotiondataarechosenfromdifferentdestructiveearthquakesaroundtheworldearthquakename,dateofearthquake,datasource,recordname,peakgroundaccelerations(pga)forthecomponents,effectivedurationsandfaulttypesforeachdataarepresentedintheTable1.,respectively.
Thepeakgroundaccelerationsareintherange0.046to0.395g,wheregisaccelerationduetogravity.Allgroundmotiondataarerecordedinnear-fieldregionasinmaximum20kmdistance.
DESCRIPTIONOFTHEFRAMESTRUCTURES
3,5,8and15-storyR\Cframestructureswithtypicalcross-sectionsandsteelreinforcementsareshowninFigure1.ThereinforcedconcreteframestructureshavebeendesignedaccordingtotherulesoftheTurkishCode.Thestructureshavebeenconsideredasanimportantclass1withsubsoiltypeofZ1andinseismicregion1.Thedead,liveandseismicloadshavebeentakenaccountduringdesign.
Allreinforcedconcreteframestructuresconsistthree-bayframe,spacedat800cm.Thestoryheightis300cm.Thecolumnsareassumedasfixedontheground.Yieldstrengthofthesteelreinforcementsis22kN/cm2andcompressivestrengthofconcreteis1.6kN/cm2.
Thefirstnaturalperiodofthe3-storyframestructureiscomputed0.54s.Thecross-sectionofallbeamsinthisframeisrectangular-shapeswith25cmwidthand50cmheight.Thecross-sectionofallcolumnsis30cmx30cm.Thefirstnaturalperiodof5-storyframestructureis0.72sandthecross-sectionofbeamsis25cmwidthand50cmheightsimilarto3-storyframe.Cross-sectionofcolumnsatthefirstthreestoriesis40cmx40cmandatthelasttwostories,itis30cmx30cm.Theeight-storyand15-storyframestructureshavenaturalperiodof0.90sand1.20s.Thecrosssectionofbeamsforbothframestructuresis25cmx55cm.The8-storyframestructurehas50cmx50cmcolumnsforthefirstfivestoriesand40cmx40cmforthelastthreestories.Thecrosssectionofcolumnsforfirsteightstoriesinthe15-storyframestructuresis80cmx80cmandatthelastsevenstories,itis60cmx60cm.
NONLINEARSTATICPUSHOVERANALYSISOFFRAMESTRUCTURES
Forlowperformancelevels,toestimatethedemands,itisrequiredtoconsiderinelasticbehaviorofthestructure.Pushoveranalysisisusedtoidentifytheseismichazards,selectionoftheperformancelevelsanddesignperformanceobjectives.InPushoveranalysis,applyinglateralloadsinpatternsthatrepresentapproximatelytherelativeinertialforcesgeneratedateachfloorlevelandpushingthestructureunderlateralloadstodisplacementsthatarelargerthanthemaximumdisplacementsexpectedindesignearthquakes(Li,Y.R.,1996).Thepushoveranalysisprovidesashearvs.displacementrelationshipandindicatestheinelasticlimitaswellaslateralloadcapacityofthestructure.Thechangesinslopeofthiscurvegiveanindicationofyieldingofvariousstructuralelements.Themainaimofthepushoveranalysisistodeterminememberforcesandglobalandlocaldeformationcapacityofastructure.Theinformationcanbeusedtoassesstheintegrityofthestructure.
Afterdesigninganddetailingthereinforcedconcreteframestructures,anonlinearpushoveranalysisiscarriedoutforevaluatingthestructuralseismicresponse.ForthispurposethecomputerprogramDrain2Dhasbeenused.Threesimplifiedloadingpatterns;triangular,(IBC,k=1),(IBC,k=2)andrectangular,wherekisanexponentrelatedtothestructureperiodtodefineverticaldistributionfactor,areusedinthenonlinearstaticpushoveranalysisof3,5,8and15-storyR\Cframestructures.
Loadcriteriaarebasedonthedistributionofinertialforcesofdesignparameters.Thesimplifiedloadingpatternsasuniformdistribution,triangulardistributionandIBCdistribution,theseloadingpatternsarethemostcommonloadingparameters.
VerticalDistributionofSeismicForces:
(1)
(2)
where:
Cvx=Verticaldistributionfactor
V=Totaldesignlateralforceorshearatthebaseofstructure
wiandwx=Theportionofthetotalgravityloadofthestructure
hiandhx=Theheightfromthebase
k=Anexponentrelatedtothestructureperiod
Inadditiontheselateralloadings,framesaresubjectedliveloadsanddeadweights.P-△effectshavebeentakenintotheaccountduringthepushoveranalyses.Thelateralforceisincreasedfor3,5and8-storyframesuntiltheroofdisplacementreached50cmand100cmfor15-storyframe.Beamandcolumnelementsareusedtoanalyzetheframes.Thebeamsareassumedtoberigidinthehorizontalplane.Inelasticeffectsareassignedtoplastichingesatmemberends.Strain-hardeningisneglectedinallelements.Bilinearmoment-rotationrelationshipisassumedforbothbeamandcolumnmembers.Axialload-Moment,P-M,interactionrelation,suggestedbyACI318-89,isusedasyieldingsurfaceofcolumnelements.Inertialmomentofcrackedsection,Icr,isusedforbothcolumnandbeammembersduringanalyses.Icriscomputedashalfofthegrossmomentofinertia,Ig.
TheresultsofthepushoveranalysesarepresentedinFigures2to5.Thepushovercurvesareshownforthreedistributions,andforeachframestructures.Thecurvesrepresentbaseshear-weightratioversusstoryleveldisplacementsforuniform,triangularandIBCloaddistribution.ShearVwascalculatedbysummingallappliedlateralloadsabovethegroundlevel,andtheweightofthebuildingWisthesummationoftheweightsofallfloors.Besidethese,thesecurvesrepresentthelostoflateralloadresistingcapacityandshearfailuresofacolumnatthedisplacementlevel.Thechangesinslopeofthesecurvesgiveanindicationofyieldingofvariousstruc
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 文献 翻译 静力 塑性 分析 侧向 荷载 分布 方式 评估 研究
![提示](https://static.bdocx.com/images/bang_tan.gif)