大学本科外文翻译精.docx

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大学本科外文翻译精

大连理工大学外文翻译

受弯钢框架结点周期性行为Cyclicbehaviorofsteelmomentframeconnections

学院（系）：

建筑工程学院

专业：

工程管理

学生姓名：

____

学号：

___________

指导教师：

_________

完成日期：

大连理工大学

DalianUniversityofTechnology

受弯钢框架结点周期性行为Cyclicbehaviorofsteelmomentframeconnections

1.Introduction

Aimedatevaluatingthestructuralperformanceofreduced-beamsection（RBS）connectionsunderalternatedaxialloadingandlateraldisplacement,fourfull-scalespecimensweretested.ThesetestswereintendedtoassesstheperformanceofthemomentconnectiondesignfortheMosconeCenterExp-ansionundertheDesignBasisEarthquake（DBE）andtheMaximumConsideredEarthquake（MCE）.PreviousresearchconductedonRBSmomentconnections[1,2]showedthatconnectionswithRBSprofilescanachieverotationsinexcessof0.03rad.However,doubtshavebeencastonthequalityoftheseismicperformanceoftheseconnectionsundercombinedaxialandlateralloading.

TheMosconeCenterExpansionisathree-story,71,814m2（773,000ft2）structurewithsteelmomentframesasitsprimarylateralforce-resistingsystem.AthreedimensionalperspectiveillustrationisshowninFig.1.Theoverallheightofthebuilding,atthehighestpointoftheexhibitionroof,isapproxima-tely35.36m（116ft）abovegroundlevel.Theceilingheightattheexhibitionhallis8.23m（27ft）,andthetypicalfloor-to-floorheightinthebuildingis11.43m（37.5ft）.ThebuildingwasdesignedastypeIaccordingtotherequi-rementsofthe1997UniformBuildingCode.

TheframingsystemconsistsoffourmomentframesintheEast–Westdirect-ion,oneoneithersideofthestairtowers,and

–1–

受弯钢框架结点周期性行为fourframesintheNorth–Southdirection,oneoneithersideofthestairandelevatorcoresintheeastendandtwoatthewestendofthestructure[4].Becauseofthestoryheight,thecon-ceptoftheCoupled-GirderMoment-ResistingFramingSystem（CGMRFS）wasutilized.

Bycouplingthegirders,thelateralload-resistingbehaviorofthemomentframingsystemchangestoonewherestructuraloverturningmomentsareresistedpartiallybyanaxialcompression–tensioncoupleacrossthegirdersystem,ratherthanonlybytheindividualflexuralactionofthegirders.Asaresult,astifferlateralloadresistingsystemisachieved.Theverticalelementthatconnectsthegirdersisreferredtoasacouplinglink.Couplinglinksareanalogoustoandservethesamestructuralroleaslinkbeamsineccentricallybracedframes.Couplinglinksaregenerallyquiteshort,havingalargeshear-to-momentratio.

Underearthquake-typeloading,theCGMRFSsubjectsitsgirderstowariab-bleaxialforcesinadditiontotheirendmoments.TheaxialforcesintheFig.1.MosconeCenterExpansionProjectinSanFrancisco,CAgirdersresultfromtheaccumulatedshearinthelink.

2.AnalyticalmodelofCGMRF

Nonlinearstaticpushoveranalysiswasconductedonatypicalone-baymodeloftheCGMRF.Fig.2showsthedimensionsandthevarioussectionsofthemodel.Thelinkflangeplateswere28.5mm254mm（11/8in10in）andthewebplatewas9.5mm476mm（3/8in183/4in）.TheSAP2000computerprogramwasutilized

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受弯钢框架结点周期性行为inthepushoveranalysis[5].Theframewascharacterizedasfullyrestrained（FR）.FRmomentframesarethoseframesfor1170whichnomorethan5%ofthelateraldeflectionsarisefromconnectiondeformation[6].The5%valuerefersonlytodeflectionduetobeam–columndeformationandnottoframedeflectionsthatresultfromcolumnpanelzone.

Theanalysiswasperformedusinganexpectedvalueoftheyieldstressandultimatestrength.Thesevalueswereequalto372MPa（54ksi）and518MPa（75ksi）,respectively.Theplastichinges’load–deformationbehaviorwasapproximatedbythegeneralizedcurvesuggestedbyNEHRPGuidelinesfortheSeismicRehabilitationofBuildings[6]asshowninFig.

3.△ywascalcu-P–Mhingeload–deformationmodelpointsC,DandEarebasedonTable5.4from[6]for△ywastakenas0.01radperNote3in[6],Table5.8.Shearhingeload-load–deformationmodelpointsC,DandEarebasedonTable5.8[6],LinkBeam,Itema.AstrainhardeningslopebetweenpointsBand

Cof3%oftheelasticslopewasassumedforbothmodels.

Thefollowingrelationshipwasusedtoaccountformoment–axialloadinteraction[6]:

whereMCEistheexpectedmomentstrength,ZRBSistheRBSplasticsectionmodulus（in3）,istheexpectedyieldstrengthofthematerial（ksi）,Pistheaxialforceinthegirder（kips）andistheexpectedaxialyieldforceoftheRBS,equalto（kips）.TheultimateflexuralcapacitiesofthebeamandthelinkofthemodelareshowninTable1.Fig.4showsqualitatively

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受弯钢框架结点周期性行为thedistributionofthebendingmoment,shearforce,andaxialforceintheCGMRFunderlateralload.Theshearandaxialforceinthebeamsarelesssignificanttotheresponseofthebeamsascomparedwiththebendingmoment,althoughtheymustbeconsideredindesign.Thequalita-tivedistributionofinternalforcesillustratedinFig.5isfundamentallythesameforbothelasticandinelasticrangesofbehavior.Thespecificvaluesoftheinternalforceswillchangeaselementsoftheframeyieldandinternalfor-cesareredistributed.ThebasicpatternsillustratedinFig.5,however,remainthesame.

Inelasticstaticpushoveranalysiswascarriedoutbyapplyingmonotonicallyincreasinglateraldisplacements,atthetopofbothcolumns,asshowninFig.6.AfterthefourRBShaveyieldedsimultaneously,auniformyieldinginthewebandattheendsoftheflangesoftheverticallinkwillform.Thisistheyieldmechanismfortheframe,withplastichingesalsoformingatthebaseofthecolumnsiftheyarefixed.ThebaseshearversusdriftangleofthemodelisshowninFig.7.Thesequenceofinelasticactivityintheframeisshownonthefigure.Anelasticcomponent,alongtransition（consequenceofthebeamplastichingesbeingfosimultaneously）andanarrowyieldplateaucharacterizethepushovercurve.

Theplasticrotationcapacity,qp,isdefinedasthetotalplasticrotationbeyondwhichtheconnectionstrengthstartstodegradebelow80%[7].ThisdefinitionisdifferentfromthatoutlinedinSection9（AppendixS）oftheAISCSeismicProvisions

–4–

受弯钢框架结点周期性行为[8,10].UsingEq.

（2）derivedbyUangandFan[7],anestimateoftheRBSplasticrotationcapacitywasfoundtobe0.037rad:

FyfwassubstitutedforRy•Fy[8],whereRyisusedtoaccountforthediffer-encebetweenthenominalandtheexpectedyieldstrengths（Grade50steel,Fy=345MPaandRy=1.1areused）.

3.Experimentalprogram

Theexperimentalset-upforstudyingthebehaviorofaconnectionwasbasedonFig.6（a）.Usingtheplasdisplacementdp,plasticrotationgp,andplasticstorydriftangleqpshowninthefigure,fromgeometry,itfollowsthat:

inwhichdandgincludetheelasticcomponents.Approximationsasaboveareusedforlargeinelasticbeamdeformations.ThediagraminFig.6（a）suggestthatasubassemblagewithdisplacementscontrolledinthemannershowninFig.6（b）canrepresenttheinelasticbehaviorofatypicalbeaminaCGMRF.

Thetestset-upshowninFig.8wasconstructedtodevelopthemechanismshowninFig.6（a）and（b）.Theaxialactuatorswereattachedtothree2438mm×1219mm×1219mm（8ft×4ft×4ft）RCblocks.Theseblocksweretensionedtothelaboratoryfloorbymeansoftwenty-four32mmdiameterdywidagrods.Thisarrangementpermittedreplacementofthespecimenaftereachtest.

Therefore,theforceappliedbytheaxialactuator,P,canberesolvedintotwoorthogonalcomponents,PaxialandPlateral.Sincetheinclinationangleoftheaxialactuatordoesnotexceed3.0,thereforePaxialisapproximatelyequaltoP[4].However,

–5–

受弯钢框架结点周期性行为thelateralcomponent,Plateral,causesanadditionalmomentatthebeam-tocolumnjoint.Iftheaxialactuatorscompressthespecimen,thenthelateralcomponentswillbeaddingtothelateralactuatorforces,whileiftheaxialactuatorspullthespecimen,thePlateralwillbeanopposingforcetothelateralactuators.Whentheactuatorsundergoaxialactuatorsundergoalateraldisplacement_,theycauseanadditionalmomentatthebeam-to-columnjoint（P-△effect）.Therefore,themomentatthebeam-tocolumnjointisequalto:

whereHisthelateralforces,Listhearm,Pistheaxialforceand_isthelateraldisplacement.

Fourfull-scaleexperimentsofbeamcolumnconnectionswereconducted.

AllofthecolumnsandbeamswereofA572Grade50steel（Fy344.5MPa）.Theactualmeasuredbeamflangeyieldstressvaluewasequalto372MPa,whiletheultimatestrengthrangedfrom502MPa（72.8ksi）to543MPa（78.7ksi）.

Thespecimensweredesignatedasspecimen1throughspecimen

4.TestspecimensdetailsareshowninFig.9throughFig.12.Thefollowingfeatureswereutilizedinthedesignofthebeam–columnconnection:

TheuseofRBSinbeamflanges.Acircularcutoutwasprovided,asillustr-atedinFigs.11and12.Forallspecimens,30%ofthebeamflangewidthwasremoved.Thecutsweremadecarefully,andthengroundsmoothinadirect-tionparalleltothebeamflangetominimizenotches.

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受弯钢框架结点周期性行为Useofafullyweldedwebconnection.Theconnectionbetweenthebeamwebandthecolumnflangewasmadewithacompletejointpenetrationgrooveweld（CJP）.AllCJPweldswereperformedaccordingtoAWSD1.1StructuralWeldingCode

UseoftwosideplatesweldedwithCJPtoexteriorsidesoftopandbottombeamflan-ges,fromthefaceofthecolumnflangetothebeginningoftheRBS,asshowninFigs.11and12.TheendofthesideplatewassmoothedtomeetthebeginningoftheRBS.ThesideplateswereweldedwithCJPwiththecolumnflanges.Thesideplatewasadded