Finite Element Analysis of Steel Beam to Column co

1、ThePennsylvaniaStateUniversityTheGraduateSchoolCollegeofEngineeringFiniteElementAnalysisofSteelBeamtoColumnConnectionsSubjectedtoBlastLoadsAThesisProposalinCivilEngineeringByTapanSabuwalaSubmittedinPartialFulfillmentoftheRequirementsfortheDegreeofMasterofScienceAugust2001TapanSabuwala1ABSTRACTTheaimofthisstudyistoanalyzeandassessthebehaviorofsteelconnectionssubjectedtoblastloadsusingfiniteelementanalysis.Threedifferenttypesofconnectionshavingvaryingconnectiondetailswillbeanalyzed.Theseconnectio。

2、ndetailsarepartofthe8connectiondetailsthathadbeentestedbytheAISCNorthridgeMomentConnectionTestProgram(Engelhardtetal1995).OnthebasisofthesetestsrecommendationswereproposedforimprovingconnectionperformancewhichhavebeenacceptedbytheFederalEmergencyManagementAgency(FEMA)andhavebeenincludedinpartintheRecommendedSeismicDesignCriteriaForNewSteelMomentFrameBuildings(FEMA,2000).Thisstudyaimsatevaluatingtheefficiencyoftheseconnections,whichhavebeendesignedforseismicloads,againstblastloads.Forthisstudythe。

3、finiteelementcodeABAQUSwillbeusedtodevelopthevariousconnectionmodels.Thefiniteelementmodelswillbecalibratedusingtestdata.Theverifiedmodelswillthenbesubjectedtosimulatedblastloadsandtheefficiencyandbehavioroftheconnectionswillbeanalyzed.TapanSabuwala21.INTRODUCTION2.PROBLEMSTATEMENT3.OBJECTIVES4.SCOPEOFWORK5.LITERATUREREVIEW6.EXPERIMENTALDATA7.ANALYTICALPROGRAM8.ANTICIPATEDCONCLUSIONS9.REFERENCESTapanSabuwala31.INTRODUCTIONInrecenttimesmanystructureshavebeensubjectedtoblastloadsduetoactsofterrori。

4、smandsteelframesformamajorpartofthesetargetedstructures.Hencethebehaviorofstructuralsteelconnectionssubjectedtoblastloadsisofinterest.Forfacilitiessubjectedtoblastloads,theconnectionsdetailshavebeenshowntoplayamajorpartintheresponseofthestructureofsuchhighratedynamicloading.Thusabetterunderstandingofbehaviorofstructuralsteelconnectionsunderblastloadsisveryimportant.Theguidelinescurrentlyusedforthedesignofstructuralsteelconnectionssubjectedtodynamicloadsinducedduringblastsorearthquakeshaveprovedt。

5、obeinadequatejudgingfromthepoorperformanceofsteelframesduringthebombingsinrecenttimesandalsoduringseismiceventslikethe1994Northridgeearthquake.Importantdesignmodificationswereintroducedforconnectionssubjectedtoseismicloadsafterextensiveassessmentsoftheobserveddamage(Engelhardtet.al.,1995).Howeverthesemodifieddesigndetailsmightprovetobeinsufficientwhensubjectedtohighratedynamicloadssuchasthosegeneratedduringanexplosion.Thereforeitisimportanttoassessthebehaviorofsuchstructuresunderblastloads.Curre。

6、ntdesignrecommendationsforblastresistantstructuresinTM-51300(Dept.oftheArmy,1990)includeguidelinesforthesafedesignofblastresistantsteelconnections.Howevertheadequacyofthesedesignproceduresisnotwellunderstoodasnotmuchresearchhasbeendoneinthisfieldleadingtoadearthofinformationregardingthebehaviorofsteelconnectionsubjectedtoblastloads.Theproposedstudyaimsatprovidingabetterunderstandingofthebehaviorofsteelconnectionsunderblastloadsthroughfiniteelementanalysis.TheadequacyofsteelTapanSabuwala4connecti。

7、onsthatwereproposedforresistanceagainstseismicloadswillbeassessedwhentheseconnectionsaresubjectedtoblastloads.Thisstudyalsoaimsatprovidingabetterunderstandingofthefiniteelementmodelingofsteelconnections.Itisimportanttocorrectlycharacterizetheinteractionofthevariouscomponentsofasteelconnectionsuchasboltsandwelds.Forthisitisimportanttounderstandandadequatelymodelthecontactinteractionbetweenthevariousinteractingpartsoftheconnectionandtocorrectlyspecifytheirconstitutiveproperties.Theproposedstudyaim。

8、stoachievethisusingthecapabilityprovidedinthefiniteelementpackageABAQUStomodelvarioustypesofcontactsimulationsandmaterialbehavior,whichmaythenserveasareferenceforfuturefiniteelementmodelsinvolvingsuchinteractions.Threedifferentconnectiondetails,whichhadbeenusedintheAISCNorthridgeMomentConnectionTestProgram(Engelhardtet.al.,1995),havebeenchosenforthestudy.Thefirstspecimenisastandardweldedbeamboltedflangetypeofconnection,whichrepresentsatypicalPre-Northridgeconnection.Theothertwoconnections,Specim。

9、ens7and8,havebeenmodifiedandstrengthenedbyaddingcoverplatestothebeamflanges,andcontinuityplatesforthecolumntogivebetterperformancewhensubjectedtoseismicloads,andhavebeenselectedfortheirsuperiorperformanceduringtheexperimentalstudy.TheconnectiondetailsforSpecimens7and8aresamebutthematerialpropertiesforthesespecimensaredifferent.Finiteelementmodelsofthese3connectiontestswillbepreparedusingtheFEcodeABAQUS.Thefiniteelementmodelswillbecalibratedusingtheavailableexperimentaldatafromthetests.Oncethemod。

10、elshavebeenverified,theywillbesubjectedtosimulatedblastloadsandtheresultsobtainedfromthesesimulationswillbeusedtoanalyzethebehavioroftheseconnectionsunderhighratedynamicloading.TapanSabuwala52.PROBLEMSTATEMENTBlastresistantsteelconnectionsarecurrentlydesignedusingthedesigncriteriadevelopedbytheindustryonthebasisoftheoreticalandexperimentalinvestigations.However,datafromtherecentactsofdomesticterrorismandseismiceventssuggeststhattheperformanceofsteelframesagainstseismicloadsaswellasblastloadsisnot。