简介:TheSutongBridgeinChinaopenedtotrafficin2008,andisanarterialconnectionbetweenthecitiesofNantongandSuzhou.Itisacable-stayedbridgewithamainspanof1,088m.Duetoatightconstructionscheduleandlackofsuitableseismicdevicesatthetime,fixedsupportswereinstalledbetweenthepiersandthegirderinthetransversedirection.Asaresult,significanttransverseseismicforcescouldoccurinthepiersandfoundations,especiallyduringareturnperiodofa2500-yearearthquake.Therefore,thepiers,foundationsandfixedbearingshadtobedesignedextraordinarilystrong.However,whenlargerearthquakesoccur,thebearings,piersandfoundationsarestillvulnerable.Therecentrapiddevelopmentsinseismictechnologyandtheperformance-baseddesignapproachofferabetteropportunitytooptimizethetransverseseismicdesignfortheSutongBridgepiers.TheoptimizeddesigncanbeappliedtotheSutongBridge(asaretrofit),aswellasotherbridges.Seismicdesignalternativesutilizingviscousfluiddampers(VFD),orfrictionpendulumslidingbearings(FPSB),ortransverseyieldingmetallicdampers(TYMD)arethoroughlystudiedinthiswork,andtheresultsarecomparedwiththosefromthecurrentconditionwithfixedtransversesupportsandahypotheticalconditioninwhichonlyslidingbearingsareprovidedontopofthepiers(thegirdercanmove"freely"inthetransversedirectionduringtheearthquake,exceptforfrictionalforcesoftheslidingbearings).Parametricanalyseswereperformedtooptimizethedesignoftheseproposedseismicdevices.Fromthecomparisonofthepeakbridgeresponsesintheseconfigurations,itwasfoundthatbothVFDandTYMDareveryeffectiveinthereductionoftransverseseismicforcesinpiers,whileatthesametimekeepingtherelativetransversedisplacementsbetweenpiersandtheboxgirderwithinacceptablelimits.However,comparedtoVFD,TYMDdonotinteractwiththelongitudinaldisplacementsofthegirder,andhavesimplerdetail