简介：A3DfiniteelementmodelfortheTaizhouYangtzeRiverBridge,thefirsttriple-towerlong-spansuspensionbridgeinChina,isestablishedbasedonthenonlinearfiniteelementsoftwareABAQUS,andthedynamiccharacteristicsofthebridgeareanalyzedusingtheLANCZOSeigenvaluesolutionmethod.Thestudyfocusesontheeffectsofthevertical,lateralandtorsionalstiffnessofthesteelboxgirder,therigidcentralbuckleandtheelasticrestraintsconnectingthetowersandthesteelboxgirderonthedynamiccharacteristicsofthetriple-towersuspensionbridge.Ourresultsshowthat,ingeneral,thedynamiccharacteristicsofthetriple-towersuspensionbridgearesimilartothoseoftwo-towersuspensionbridges.Thevertical,lateralandtorsionalstiffnessofthesteelboxgirderhavedifferenteffectsonthedynamiccharacteristicsoftriple-towersuspensionbridges.Theelasticre-straintshaveamoresignificanteffectonthedynamiccharacteristicsthanthecentralbuckle,anddecreasingthestiffnessoftheelasticrestraintsresultsintheappearanceofalongitudinalfloatingvibrationmodeofthebridge.Also,rigidcentralbuckleshaveagreaterinfluenceonthedynamiccharacteristicsoftriple-towersuspensionbridgesthanonthoseoftwo-towersuspensionbridges.Theresultsobtainedcouldserveasavaluablenumericalreferenceforanalyzinganddesigningsuper-long-spantriple-towersuspensionbridges.

简介：Anovelmodelisproposedwhichcomprisesofabeambridgesubjectedtoanaxialloadandaninfiniteseriesofmovingloads.Themovingloads,whosedistancebetweentheneighbouringonesisthelengthofthebeambridge,coupledwiththeaxialforcecanleadthevibrationofthebeambridgetocodimension-twobifurcation.Ofparticularconcernisaparameterregimewherenon-persistencesetregionsundergoatransitiontopersistenceregions.Theboundaryofeachstriperepresentsabifurcationwhichcandrivethesystemoffakindofdynamicsandjumptoanotherone,causingdamageduetotheresultingamplitudejumps.TheGalerkinmethod,averagingmethod,invertiblelineartransformation,andnearidentitynonlineartransformationsareusedtoobtaintheuniversalunfoldingforthecodimension-twobifurcationofthemid-spandeflection.Theefficiencyofthetheoreticalanalysisobtainedinthispaperisverifiedvianumericalsimulations.

简介：AnumberofdrybridgeshavebeenbuilttosubstitutefortheroadbedontheQinghai-TibetRailway,China.Theaimofthisstudywastoinvestigatetheexothermicprocessofcast-in-place(CIP)pilefoundationofadrybridgeanditsharmtothestabilityofnearbyfrozenground.Wepresent3Dheatconductionfunctionsofaconcretepileandoffrozengroundwithrelatedboundaries.Ouranalysisisbasedonthetheoryofheatconductionandtheexponentlawdescribingtheadiabatictemperaturerisecausedbyhydrationheat.ResultsundercontinuousandinitialconditionswerecombinedtoestablishafiniteelementmodelofaCIPpile-frozengroundsystemforadrybridgeunderactualfieldconditionsincoldregions.NumericalresultsindicatedthattheprocesscouldeffectivelysimulatetheexothermicprocessofCIPpilefoundation.ThermaldisturbancetofrozengroundunderalongdrybridgecausedbythecastingtemperatureandhydrationheatofCIPpileswassubstantialandlong-lasting.Thesimulatedthermalanalysisresultsagreedwithfieldmeasurementsandsomesignificantrulesrelatingtotheproblemwerededucedandconclusionsreached.