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大跨度钢桁架拱桥风振研究.docx

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大跨度钢桁架拱桥风振研究 Abstract Inrecentyears,theconstructionoflarge-spansteeltrussarchbridgeshasbeenincreasinglyfavoredbypeopleduetoitsgreatcapabilitiesofaccommodatingtraffic,reducingcongestionandpromotingtransportationdevelopment.Amongallthedesignconcernsforlarge-spansteeltrussarchbridges,wind-inducedvibrationsareoneofthemostcritical.Thispaperfocusesontheresearchofwind-inducedvibrationsoflarge-spansteeltrussarchbridges,includingthetheoreticalmechanismofwind-inducedvibrations,theinfluencingfactorsofwind-inducedvibrations,andthecorrespondingcontrolmethods. Introduction Large-spansteeltrussarchbridgesarewidelyusedinmodernbridgeconstructionsduetotheirexcellentmechanicalproperties.However,wind-inducedvibrationsareoneofthemostsignificantconcernsforsuchbridges,astheymaycauseirreversibledamageandresultinsafetyhazards.Therefore,exploringthewind-inducedvibrationmechanismoflarge-spansteeltrussarchbridgesanddevelopingeffectivecontrolandpreventionmeasuresareextremelyimportantandnecessary. TheoreticalMechanismofWind-inducedVibrations Wind-inducedvibrationsoriginatefromtheinteractionbetweenthewindandthebridgestructures.Theaerodynamicforceactingonthebridgesurfacescangeneratevibrationresponsesinthestructures.Thevibrationresponsescanbeclassifiedintotwotypes,namely,verticalvibrationsandtorsionvibrations. VerticalVibrations Verticalvibrationisacommonvibrationmodeoflarge-spansteeltrussarchbridgescausedbythecombinedeffectsofvortexsheddingandthebluffbodyeffect.Ingeneral,verticalvibrationsareinducedbytheunsteadyflowaroundthebridgesurface,andthephenomenoncanbeexplainedbytheVortex-InducedVibration(VIV)theory.TheVIVtheoryindicatesthatthevortexsheddingaroundthebridgesurfacescausesalternationbetweentheliftforceandthedragforce,generatingverticalvibrationsofthebridge. TorsionVibrations Torsionvibrationisanothertypicalvibrationmodeoflarge-spansteeltrussarchbridges,characterizedbythetwistingresponseofthebridgestructure.Thisvibrationmodeismainlycausedbythewindflowseparationatthebridgesurface.Thevortexsheddi