考虑桥台性能影响的连续梁桥地震易损性分析

Seismic fragility analysis of a continuous bridge considering the performance of abutments

由于目前桥台性能对整个桥梁结构地震易损性影响的研究较少,本文对考虑桥台性能的连续梁桥地震易损性进行研究。以一典型三跨连续梁桥为例,分别建立了有、无桥台两种情况下的有限元模型;根据四类场地从PEER(Pacific earthquake engineering research center)强震数据库中各选取100条地震波来模拟地震动的不确定性,并组成"结构—地震波"样本对;采用Open Sees对结构进行非线性时程分析后得到构件响应,并定义了各个构件的四种极限破坏状态;采用可靠度理论得到各个构件的地震易损性曲线。研究表明:桥台对构件的地震响应有显著影响,若不考虑桥台作用将会使其他构件的损伤概率明显增大;且在同一场地条件下,墩柱最易损伤,滑动支座次之,而桥台最不易损伤。

There is limited work on the impact of abutment property on the seismic fragility of bridge. Therefore,the seismic fragility analysis of continuous bridge considering the effects of abutment was presented in this paper. First-ly ,finite element models for the three-span continuous bridges with and without abutments were established. Sec-ondly, four sets of 100 earthquake ground motion records were selected from the Pacific Earthquake Engineering Research Center（PEER ） strong motion database for four different site conditions to simulate the uncertainty of ground motions. And they were randomly combined with bridge samples. Thirdly, the seismic responses of each component were obtainedvia nonlinear time history analysis using OpenSees and the four limit states of different components were defined. Lastly, fragility curves of the components were obtained via reliability and probability methods. The study found that the seismic responses of the bridge were significantly influenced by abutments,and the damage probability of other componentsconsiderably increased for the bridge without abutments. Under the same site conditions,piers were the most vulnerable components,followed by the sliding bearings,and then abutments.