基于IDA的高速铁路大跨度斜拉桥地震易损性分析

Seismic Vulnerability Analysis of High-speed Railway Long-span Cable-stayed Bridges Based on IDA

为研究高速铁路大跨度斜拉桥的地震易损性,以我国西部某主桥跨径为249.5m+550m+550m+249.5m的三塔四跨铁路斜拉桥为研究对象,利用有限元软件SAP2000建立其动力有限元分析模型,采用增量动力分析(IDA)获得结构地震响应,结合对数回归分析最终获得各关键构件的地震易损性曲线。结果表明:二次拟合得到的概率地震需求模型整体略优于一次拟合;在纵向地震作用下,支座呈现出较高的损伤概率,其中固定支座损伤概率最大;桥塔和桥墩的损伤相对较低。因此在大跨度铁路斜拉桥抗震设计中,应重点考虑位移和变形的控制。

In order to study the seismic vulnerability of high-speed railway long-span cable-stayed bridge,a three-tower and four-span railway cable-stayed bridge with a main bridge span of 249.5m+550m+550m+249.5m in western China is taken as the research object,and its dynamic finite element analysis model is established by using finite element software SAP2000.The seismic response of the structure is obtained by incremental dynamic analysis(IDA),and the seismic vulnerability curve of each key component is obtained by logarithmic regression analysis.The results show that the probabilistic seismic demand model obtained by quadratic fitting is slightly better than the first fitting,and the bearing presents a higher damage probability under the action of longitudinal earthquake,in which the damage probability of fixed bearing is the highest.The damage of bridge tower and pier is relatively low.Therefore,the control of displacement and deformation should be considered in the seismic design of long-span railway cable-stayed bridge.