铁路桥梁的地震易损性分析

Seismic vulnerability analysis of railway bridges under Wenchuan earthquake

近年来我国发生的大地震,尤其是5·12汶川地震表明,铁路桥梁作为交通系统中的枢纽结构,在地震中极易受损.多跨连续钢筋混凝土桥是铁路桥梁中常见的结构形式.故采用国家强震动台网中心提供的汶川地震强震波和NGA强震数据库提供的地震波,以位移延性比为破坏指标,应用结构分析软件SAP2000,分别对多跨连续钢筋混凝土铁路桥进行非线性时程分析,并对其结果进行回归,得出以PGA(Peak Ground Acceleration)为自变量,结构超过某一特定损坏状态的概率为因变量的地震易损性曲线;最后分析了该类铁路桥在地震作用下的地震易损性.

Recent earthquakes that happened in China, especially the 5.12 Wenchuan earthquakes, have highlighted the vulnerability of railway bridge structures to moderate-to-strong ground motion. The multi-span continuous reinforced concrete structure is one common type of railway bridge struc- ture. This paper adopts the strong ground motion waves supplied by China National Strong Motion Network Center and PEER NGA Database and performs a series of nonlinear time-history analyses for a typical continuous railway bridge through the structure analysis software SAP2000, respectively. Be- sides, the damage index is the displacement ductility ratio. Then the displacement ductility ratio data is regressed in order to get the vulnerability curves that show the relationship of the independent index PGA （Peak Ground Acceleration）and the probability of the damage over a particular state. Finally, the seismic vulnerability analysis of the railway bridge under earthquakes especially the Wenchuan earthquake is performed.