基于场地效应的山区高墩桥梁随机地震响应分析.pdf

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1、第29卷第6期公路交通科技v01．29No．62012年6月JournalofHighwayandTransportationResearchandDevelopmentJun．2012d硝：10．3969／j．issn．1002-0268．2012．06．016基于场地效应的山区高墩桥梁随机地震响应分析贾宏宇，郑史雄(西南交通大学土木工程学院，四川成都610031)摘要：为研究场地效应对高墩桥粱随机地震响应的影响规律，基于随机振动理论，研究了不同墩高和墩高差时场地效应对山区高墩桥梁在强地震作用下多点激励随机响应规律。对基于ANSY

2、S的随机振动计算理论进行推导并建立三维数值有限元模型。对不同墩高和墩高差的山区高墩桥粱进行不同场地条件下的多点激励随机地震分析。研究表明：场地效应对高墩桥粱地震响应影响显著。软场地条件下，桥墩位移和主粱轴力均较硬、中场地时大；随着墩高的增加，硬、中、软场地效应对主梁轴力影响先增大后减·1、；随着墩高差的增加，主粱轴力变化规律性不强，成波动性变化；主梁横桥向弯矩对场地效应敏感，软场地时响应是硬、中场地时的5一12倍，靠近高墩处的边跨反应比矮墩处边跨明显；随着墩高差的增加，软场地对主梁弯矩响应放大作用也随之增加。关键词：桥梁工程；高墩桥

3、粱；场地效应；随机振动；多点激励；强地震中图分类号：U442．5+5文献标识码：A文章编号：1002-0268(2012)06—0093一05AnalysisofRandomSeismicResponseofHigh-risePierBridgeinMountainAreaBasedonSiteEffectJIAHongyu，ZHENGShixiong(SchoolofCivilEngineering，SouthwestJiaotongUniversity，ChengduSiehuan610031，China)Abstract：In

4、ordertoinvestigatetheseismicresponseofhigh—risepierbridgeduetositeeffect，basedonFandomvibrationtheory，randomresponseofhish-risepierbridgeinmountainareasubjectedtomulti—pointexcitationofstrongearthquakecausedbylocalsiteeffectwithdifferentpierheights(PH)andheightdifferen

5、cesbetweenhighpierandlowpier(HDHL)Wasresearched．TheformulaofANSYSbasedrandomvibrationtheorywasderivedandthe3DfiniteelementmodelWasestablished．Suchrandomresponsesubjectedtomulti．pointexcitationunderdifferentcasecalculations，different10ealsiteeffects，anddifferentPHsandHD

6、HLs，wereconductedindetail．Theresultshowsthat(1)seismicresponseofhig}l-risepierbridgeWaSaffectedsignificantlybylocalsiteeffects，undersoftgroundcondition，thepierdisplacementandthemainbeamaxialforcewerelargerthanthoseunderothergroundconditions；(2)mainbeamaxialforcerespons

7、esfirstincreasedandthendecreasedwiththeheightincreaseofpiersinhard，mediumandsoftgroundeffect；(3)mainbeamaxialforceresponseroleswerenotclearwithHDHLincrease，onlyfluctuated；(4)lateralmomentofmainbeamWassensitivetolocalsiteeffect．theresponseundersoftgroundconditionWagthe5

8、—12timeslargerthanthatunderhard，mediumgroundconditions，theseismicresponseofsidespannearhiighpierWasstrongerthanthatof