近场多脉冲地震作用下高墩桥梁地震响应分析  

Seismic Response Analysis of High-Pier Bridge under Near-Fault Multiple Pulse Record Excitation

作　　者：郑史雄[1] 陈志强[1] 陈志伟[1] 李晰[1] ZHENG Shixiong;CHEN Zhiqiang;CHEN Zhiwei;LI Xi(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院

出　　处：《西南交通大学学报》2019年第5期897-907,共11页Journal of Southwest Jiaotong University

基　　金：中国铁路总公司科技开发项目(2015G002-A);教育部春晖计划资助项目(Z2014032)

摘　　要：为了研究近断层地震的多脉冲效应对不规则高墩大跨桥梁非线性地震响应的影响,首先,采用眼观识别的方法选取了典型的多脉冲、单脉冲和非脉冲3组地震动;然后,采用小波变换识别方法和能量识别方法对其脉冲性进行识别,研究了脉冲地震动识别方法对多脉冲地震动的适用性;最后,以某大跨度高墩桥梁为例,基于OpenSees建立了其非线性有限元模型,对其进行了非线性地震响应分析,对比研究了近断层多脉冲地震动及单脉冲地震动对不规则高墩桥梁非线性地震响应的影响.研究结果表明:现有的近断层脉冲识别方法只适用于速度时程中只含有一个主脉冲的地震动,对于多脉冲地震动,其失效的可能性非常大;近断层脉冲地震动对不规则高墩桥梁具有更强的破坏性,特别是在多脉冲地震作用下,1号、2号两个高墩的墩顶位移需求分别增加了118.9%和109.6%,墩底弯矩和墩底曲率也有明显的增大;近场多脉冲地震作用下主梁的碰撞次数增大了3~5倍,碰撞力也会增大2~3倍,主梁更容易发生严重的碰撞破坏,在抗震设计时应采取适当防撞措施.The multiple pulse effect of near-fault seismic records on the nonlinear seismic response of high pier railway bridges(HPRB) was investigated. First,three representative groups of seismic records,namely,single pulse record(SPR),multiple pulse record(MPR) and none pulse record(NPR) were selected by visual inspection.Second,pulse characteristics were quantitatively identified using wavelet analysis method(WAM) and energybased approach(EBA) to investigate if impulse ground motion identification method was applicable to MPR.Finally,a typical HPRB,located in the southern region of China,was adopted as the research object,the nonlinear finite element model was established in OpenSees platform,and the non-linear seismic response analysis of the HPRB was carried out. The effects of MPR and SPR on the nonlinear seismic response of the HPRB were compared. The results obtained from the analyses indicate that the WAM and EBA are applicable to ground motions with only one dominant pulse in the velocity history,and are not applicable to multiple pulse ground motions. Near-fault MPRs and SPRs pose the risk of stronger damage to irregular high pier bridges than NPRs.Under MPR excitation,the top displacement of pier 1 and pier 2 is,respectively,118.9% and 109.6% larger than under NPR excitation. The bending moment and the curvature at the bottom of the pier also increase. Near-fault MPR is found to produce pounding force and pounding times that are,respectively,3-5 times and 2-3 times greater than those by NPR excitation. In the near field multiple pulse earthquake,the main beam is more likely to cause severe impact damage, and thus, the appropriate anti-collision measures should be adopted in seismic design.

关 键 词：近场多脉冲地震动 脉冲识别 高墩桥梁 非线性地震响应 碰撞 

分 类 号：U442.5[建筑科学—桥梁与隧道工程]