Behavior-and-Design-of-Single-Plate-Shear-Connecti

BehaviorandDesignofSinglePlateShearConnectionsAbolhassanAstanehAuthorAbolhassanAstanehreceivedaPh.D.incivilengineering(struc-tures)fromtheUniversityofMichigan,AnnArborin1982.HeiscurrentlyanassistantprofessorintheDepartmentofCivilEngineer-ing,UniversityofCaliforniaatBerkeley.Hismainareasofinterestarebehavioranddesignofsteelstructuresandtheircomponentssubjectedtocyclicormonotonicloading.Dr.AstanehisaregisteredprofessionalengineerinMichigan.HeisaprofessionalmemberofAISC,andamemberofASCE,EERI,SSRCandtheCouncilonTallBuildingsandUrbanHabitat.SummaryThispaperpresentstheresultsofaresearchprogramrecentlycon-ductedattheUniversityofCalifor-nia.Theobjectiveoftheprogramwastostudytheactualbehaviorofsingleplateshearconnectionsunderrealisticshearandrotationcombinations.Fivefull-sizespecimensweresubjectedtorealisticshear-rotationsinthelaboratoryuntilfailureoccurred.Basedontheanalysisofthebe-haviorandfailuremodes,newdesignproceduresweredevelopedthatarepresentedinthepaper.3-1©2003byAmericanInstituteofSteelConstruction,Inc.Allrightsreserved.Thispublicationoranypartthereofmustnotbereproducedinanyformwithoutpermissionofthepublisher.NEWCONCEPTSINDESIGNOFSINGLEPLATESHEARCONNECTIONSbyA.AstanehUniversityofCaliforniaatBerkeleyINTRODUCTIONThesingleplateshearconnection,oftencalledasheartab,isprimarilyusedtotransfertheshearreactionofabeam.Inasimplysupportedbeam,inadditiontoconsiderableshearforce,theconnectionissubjectedtorotationsduetotheendrotationofthebeam.Recently,aresearchprojectwasconductedattheUniversityofCaliforniaatBerkeleytostudythebehaviorofsingleplateshearconnections(3,4,and7).Theobjectivesoftheresearchprogramwere:1.Tosubjectanumberofsingleplateshearconnectionstorealisticcombinationsofshearandrotationinordertostudytheactualbehavioroftheseconnections.2.Toanalyzethetestresultstoestablishfailuremodesandtheshearstrengthassociatedwitheachfailuremode.3.Tousetheexperimentalandanalyticalresultstodevelopcomprehensiveyetsimpledesignprocedures.ABRIEFSUMMARYOFTHERESEARCHPROJECTTheexperimentalphaseoftheprojectconsistedofconductingfivetestsusingrealisticspecimenswith3,5and7bolts.PropertiesofthetestspecimensaregiveninTable1.Figure1showsatypicaltestspecimenwhichconsistedofabeam,ashortcolumnandasingleplateconnection.Byusingtwoactuators,theconnectionineachspecimenwassubjectedtotheshear-rotationvariationgiveninFigure2.Theinelasticanalysesofalargenumberofsimplysupportedsteelbeamssubjectedtouniformloadsindicatedthattheshear-rotationrelationshipofFigure2representsarealisticvariationoftheshearreactionsandendrotationsinanactualsimplysupportedbeam(1,2).Figures3(a)showstypicalfailureofboltsthatoccurredinSpecimens1,2,3and4.Figure3(b)showsshearyielding,bearingyielding,boltfailureandweldfailurewhichoccurredinSpecimen5.Figures4and5showmoment-rotationandshear-rotationcurvesrecordedduringthetests.3-3©2003byAmericanInstituteofSteelConstruction,Inc.Allrightsreserved.Thispublicationoranypartthereofmustnotbereproducedinanyformwithoutpermissionofthepublisher.TABLE1-PropertiesofTestSpecimensTESTNO.12345NO.OFBOLTS75353DIA.OFBOLTS(in)3/43/43/43/43/4TYPEOFBOLTS*A325-NA325-NA325-NA490-NA490-NPLATEDIMENSIONS(inxinxin)21x3/8x4-1/415x3/8x4-1/49x3/8x4-1/414-1/4x3/8x3-7/88-1/4x3/8x3-7/8EDGEDISTANCE(in)1-1/21-1/21-1/21-1/81-1/8ACTUALWELDSIZE(in)1/41/41/47/327/32BEAMMATERIALA36A36A36Gr.50Gr.50PLATEMATERIALA36A36A36A36A36*Allboltsweretightenedto70%ofproofload.Inallspecimensdiameterofboltholewas1/16inchlargerthannominaldiameterofbolt.Nindicatesthatinallspecimensthreadswereincludedinshearplane.†Sizeofallweldswasspecifiedas1/4inch.Basedonthebehavioroftestspecimens,thefollowingfailuremodeswereestablished:1.Yieldingoftheplateinshear2.Yieldingoftheboltholesinbearing3.Fractureoftheedgedistanceoftheplate4.Fractureofthenetsectionoftheplate5.Fractureofthebolts6.FractureoftheweldlinesDEVELOPMENTOFDESIGNPROCEDURESThefirststepindevelopingtheproposeddesignprocedurewastoestablishfailuremodes.Thiswasdonebyconductingtheabove-mentionedtestsandbyanalyzingtheexperimentalresults.Inestablishingfailuremodes,theexperimentalresultsfromtwoparallelresearchprojectsonteeframinganddouble-angleframingconnections(1,5,6and10)werealsoconsidered.Thesecondstepwastostudyinteractionofthesefailuremodestoestablishtheirdependency.Itwasfoundthatallfailuremodesarealmostindependentwiththeexceptionoffractureofthenetsectionoftheplatewhichusuallywilloccuraftersubstantialshearandbendingyieldingoftheplate.Thethirdstepwastoprioritizethefailuremodeswithrespecttotheirdesirability.Itwasdecidedthatductilefailuremodesthatinvolveextensiveyieldingofsteel,suchasshearyieldingofplate,begivenhigherpriorityandrelativelybrittlefailuremodessuchasboltorweldfracturebegivenlowerpriority.Duringtheexperiments,itwasobservedthatweldfailuresresultedincompletelossofsupportforthebeamwhereaswhen3-4†©2003byAmericanInstituteofSteelConstruction,Inc.Allrightsreserved.Thispublicationoranypartthereofmustnotbereproducedinanyformwithoutpermissionofthepublisher.boltsfailedthebeamdroppedaboutoneinchdownandthebottomofthetopflangeofthebeamrestedonthetopofthesh