一种新的方式通过和半透过拱桥设计吊带毕业论文外文翻译Word下载.docx

一种新的方式通过和半透过拱桥设计吊带毕业论文外文翻译Word下载.docx

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Anewwaytodesignsuspendersforthroughandhalf-througharchbridges

R.J.Jiang,Y.Y.Chen,Q.M.Wu,W.M.GaiandD.M.PengShenzhenMunicipalDesign&

ResearchInstitute,Shenzhen,China

1ABSTRACT

Itiswell-knownthat,inthroughandhalf-througharchbridges,thesuspendersareimportantcomponentssincetheyconnectthebridgedecktothearchribs.Thecollapseofbridgedeckorarchribsmaybeinducedonceoneormoresuspendersarebroken.Inthispaper,thetraditionaldesignwayofthesuspendersinthroughandhalf-througharchbridgesisdiscussedfirst.Basedonthediscussion,anewwaytodesignsuspendersforarchbridgesisthenputforward.Thereasonabilityofthisnewwayisprovedbynumericalanalysisexamples.TheimpacteffectoftheremainingcomponentsofthearchbridgeduetothebreakageofoneormoresuspendersisobtainedbyappropriatesimulationusingthecomprehensivecommercialsoftwareANSYS.Itcanbeconcludedfromtheanalysisinthispaperthatthenewwaytodesignthesuspendersforthethroughandhalf-througharchbridgescanassurethesafetyofthebridgeeffectivelyeventhoughoneormoresuspendershappentobreak.

2INTRODUCTION

Withtherapiddevelopmentofnewmaterialsandconstructiontechnologies,themodernarchbridgesarenowenteringanewera.Thespanlengthofthemodernarchbridgesisincreasing,andthefirsttwolongestmodernarchbridgesaretheChaotianmenYangtseRiverBridgeandtheLupubridge,respectively.TheChaotianmenYangtseRiverBridgebuiltin2008isatiedsteeltrussarchbridgewithaspanlengthof552m;

andtheLupuBridgebuiltin2003isasteelboxarchbridgewithacentralspanlengthof550m.Theyarebothhalf-througharchbridgesandrespectivelylocatedinChongqingandShanghai,China.Archbridgescanbeclassifiedintothreecategoriesaccordingtotherelativepositionsbetweenthedeckandthearch:

deck-archbridge,half-througharchbridgeandthrougharchbridge（ChengJ.etal.2003）.Forbothhalf-througharchbridgeandthrougharchbridge,thesuspendersaretheimportantcomponentssincetheyconnectthebridgedeckwitharchribsandtransferkindsofloadsfrombridgedecktoarches,andfinallytofoundation.However,atthesametimetheyarethevulnerablememberstobedamagedorruined,becausetheyusuallyworkbothinformidablenaturalenvironmentandunderfatigue-inducedcyclingloads（LiD.S.etal.2007）.Itisafactthattheservicelifeofthesuspenderismuchshorterthanthatofthearchbridge,andthesuspendersmustbereplacedtimely（TangH.C.2005）.Thedamagetothebridgedeckorarchesmaybeinducedwhenoneormoresuspendersbreak,sometimes,eventhecollapseofthearchbridgemayhappen.Inrecentyears,theaccidentsofarchbridges’collapsecausedseverecasualtiesandhugeeconomicloss（LiD.S.andOuJ.P.2005）.Inordertoknowwellaboutthehealthconditionofsuspenders,kindsofrealtimemonitoringanddiagnoseswereconducted（LiD.S.etal.2007）.However,boththetechnologiesandthematerialsforstructuralhealthmonitoringanddiagnosearenotfullydevelopeduptonow（LiH.N.etal.2008）.Inthispaper,thetraditionaldesignwayofsuspendersinthroughandhalf-througharchbridgesisdiscussedfirst.Basedonthediscussion,anewwaytodesignthesuspendersinthroughandhalf-throughmodernarchbridgesisthenputforward.Withtheapplicationofthisnewway,thearchbridgewillremainsafeeventhoughoneormoresuspendershappentobreak.Thisnewdesignwayisadifferentmethodfromthehealthmonitoringtocontrolthesafetyofthemodernarchbridgesundertheconditionthatthebreakofthesuspenderisuncontrollable.Thereasonabilityandreliabilityofthisnewwayisstudiedandprovedbyanumericalanalysisexamplebasedonarealthrougharchbridge.TheimpacteffectoftheremainingcomponentsofthearchbridgeduetothebreakageofoneormoresuspendersisobtainedbyappropriatesimulationusingthecomprehensivecommercialsoftwareANSYS.Itcanbeconcludedfromtheanalysisinthispaperthatthenewwaytodesignthesuspendersinmodernarchbridgescanassurethesafetyofthebridgeeffectivelyeventhoughoneormoresuspendershappentobreak.

3DISCCUSIONONTRADITONALDESIGNOFARCHBRIDGESUSPENDERS

Forthrough-typeandhalf-through-typearchbridges,thesuspendersareanchoredtoarchribsatoneendandtransversebeamsattheother.Generallyspeaking,inthetraditionalarchbridgedesignthedouble-suspenderanchorage（Fig.1）insteadofthesingle-suspenderanchorageiswidelyadoptedinordertokeepthearchbridgestillsafeandmakethereplacementofthesuspendersmoreconvenientwhenonesuspenderhappenstobreak.

Figure1:

Double-suspenderanchoragetraditionallydesigned:

（a）Paralleldouble-suspenderanchorage,（b）Inclineddouble-suspenderanchorage

However,thetwosuspendersatthesameanchorageareusuallydesignedasthesamebothinmaterialandcrosssections;

i.e.,,E1=E2,A1=A2andθ1=θ2,whereE,Aandθaretheelasticmodulus,crosssectionareaandinclinedanglesofthesuspender,respectively.Thatmeanstheyhavethesameorsimilarstressandvariationofstressinservice.Theyarealsounderthesameorsimilarcorrosionenvironmentsincetheyarelocatedatthesameanchorage.Hereby,itcanbeconcludedthatthetwosuspendersatthesameanchoragewillfailatthesameorsimilartimebecauseofthealmostequallevelofbothfatigueloadandcorrosionenvironment.Basedonthediscussionabove,itcanbeseenthatthedouble-suspendersystemdesignedinthetraditionalwaywillnotimproveboththesafetyofthearchbridgeandtheconvenienceofsuspendersreplacementcomparedtothesingle-suspendersystem.

4ANEWWAYTODESIGNARCHBRIDGESUSPENDERS

Inordertokeeptheremainingstructureofarchbridgestillsafewhenonesuspenderhappenstobreak,thedouble-suspendersmustbedesignedwithdifferentservicelife.Theonlywaytoachievethisaimistodesignthetwosuspendersatthesameanchoragewithdifferenteithermaterialorcrosssectionareassincetheycarrythesamefatigueloadsandareunderthesamecorrosionenvironment.Ifthetwosuspendersatthesameanchoragearedesignedwithdifferentmaterials,theextrainconveniencebothindesignandconstructionofthearchbridgewillbeinduced.ThebetterwayistomakethetwosuspenderswithdifferentcrosssectionareasAFandAS（Fig.2）respectively.Withdifferentcrosssectionareas,thetwosuspendersatthesameanchoragewillhavedifferentstresslevelsandvariationofstresses,thatistosay,thereareσF,max≠σS,max,σF,a≠σF,a.Σmaxandσaarethemaximumstressandamplitudeofthestressofthesuspenders,respectively.Basedonthebasictheoriesofthematerialfatigue,thematerialormemberhasdifferentserviceliveswithdifferentmaximumstressandstressamplitude.

Figure2:

Double-suspenderanchoragedesignedinnewway:

Thereupon,thetwosuspendersatthesameanchoragemayhavedifferentservicelivesiftheyareappropriatelydesignedwithdifferentcrosssectionareaseventhoughtheyaremadeofthesamematerialandunderthesamefatigueloadsandcorrosionenvironment.Duringtheservicelifeofthearchbridge,thesuspenderwiththelargercrosssectionwillstillkeepthearchbridgesafewhenthesuspenderwiththesmallercrosssectionatthesameanchoragehappenstobreak.Thereasonabilityandreliabilityofthisnewwaytoconsiderthesuspenderdesignwillbeprovedbynumericalcomparisonstudyonatrough-typemodernarchbridge,ShenzhenNorthRailwayStationBridge,usingcomprehensivecommercialsoftwareANSYSinthefollowingsectioninthispaper.

5NUMERICALANALYSISEXAMPLE

5.1DescriptionofShenzhenNorthRailwayStationBridge

ShenzhenNorthRailwayStationBridgewithaspanlengthof150misathrough-typemodernconcrete-filledsteeltubulararchbridge.Itwasbuiltin2000andlocatedattheShenzhenNorthRailwayStation,spanningallrailwaysatthatstation.Rise-to-spanratioofthisbridgeis1/4.5.TheelevationviewofthebridgeisshowninFig.3.Thewidthofthegeneralbridgedeckis23.5mexceptattheendofthearchribswithabridgedeckwidthof28m.Horizontalcablesinthesteelboxgirdersofthebridgedeckareadoptedtobalancethehorizontalforceofthearchribs.Thisbridgehastwoverticalarchribsandeacharchribiscomposedoffourconcrete-filledsteeltubesandthushasatrusscrosssectionof2.0minwidthand3.0minheight.ThematerialpropertiesofthebridgearelistedinTable1.ThemoredetailsaboutthisbridgeisfoundinLietal.（2002）.

5.2Finiteelementmodeloftheexamplebridge

Adetailedfiniteelementmodel（Fig.4）oftheexamplebridgewasdevelopedusingthecomprehensivecommercialsoftwareANSYS.Inthis3dimensional（3D）finiteelementmodel,everycomponentisappropriatelymodelled.

Asmentionedabove,eacharchribiscomposedoffourconcrete-filledsteeltubes.Theseconcrete-filledsteeltubesaremodelledbyBEAM4element.Sincetheconcrete-filledsteeltubeisacompositemember,theequivalentcrosssectionalpropertiesandmaterialpropertiesareobtainedfirstbyeditinganAPDLfilebasedonsomeequivalencerules,andthenassigntheseequivalentcrosssectionalpropertiesandmaterialpropertiestothecorrespondingbeamelements.Theequivalentcrosssectionalpropertiesandmaterialpropertiesoftheconcrete-filledsteeltubesarelistedinTable2.

TheBEAM4elementisalsoadoptedtomodelthearchribbracings,thelongitudinalsteelboxgirders,thesteeltubesconnectingthefourconcrete-filledsteeltu