板式橡胶支座地震易损性分析

Research on the Seismic Vulnerability Analysis of Laminated Rubber Bearing

以一中等跨径连续梁桥为研究对象,建立了橡胶支座的滞回特性曲线以及全桥非线性动力分析模型.从太平洋地震工程研究中心(PEER)强震数据库中选取100条地震波,进行了一系列非线性时程分析,得到了橡胶支座的位移反应.根据基于性能的抗震设计思想和地震易损性分析理论,提出了板式橡胶支座4种不同损伤状态损伤指标的确定方法,并由此拟合了谱加速度与支座相对位移延性比之间的关系.基于传统可靠度概率方法,建立了橡胶支座的易损性曲线.分析结果表明,支座在地震作用下的易损性较其他构件更严重,且桥台支座比桥墩支座更容易遭受损坏;增加支座橡胶层厚度或改用聚四氟乙烯滑板支座能很好地改善桥台支座的抗震性能.

Taking a mid-span continuous bridge as the research subject,the restoring force model of rubber bearing and the dynamical model of nonlinear analysis were established.Also,100 earthquake wave records were chosen from PEER to conduct a series of nonlinear time-history analyses,and the relative displacement responses of rubber bearings were obtained.Based on the principle of Performance-Based Seismic Design and the theory of seismic vulnerability analysis,a method for determining four different damage indexes of laminated rubber bearing was proposed.According to traditional reliability probability analysis method,a curve between the spectral acceleration and the relative displacement ductility ratios of bearings was fitted,and the fragility curves of different bearings were formed.The results have demonstrated that bearing,especially the bearing on abutment,is more vulnerable than other bridge members under earthquake.Therefore,the seismic performance of bearing will be greatly improved if the thickness of rubber bearings is heightened or the PTFE sliding rubber bearings are adopted for abutment bearing.