考虑支座摩擦滑移及结构碰撞的非规则人字形桥梁地震响应分析

Seismic response research of irregular Y-shaped bridges considering frictional sliding and structural pounding

针对非规则人字形桥梁在地震作用下灾变严重的问题,以一座非规则人字形桥梁为研究对象,建立其空间分析模型,研究综合考虑支座摩擦滑移、结构碰撞对非规则人字形桥梁地震响应的影响。结果表明:邻梁间的碰撞作用可使得桥梁墩顶位移及内力相比不考虑时有所减小,但同时也使梁体产生了较大的加速度脉冲效应;当考虑支座摩擦滑移和结构碰撞时,固定墩墩顶位移和邻梁相对位移峰值有一定程度增大,然而对梁体加速度脉冲效应结果影响并无统一规律;纵向地震波作用下,非规则人字形桥梁不仅存在顺桥向的碰撞,横桥向的碰撞响应也不容忽视。非规则人字形桥梁进行抗震设计计算时应选取符合实际情况的计算模型,考虑支座摩擦滑移及结构间的碰撞。

In view of the serious problem of irregular shaped bridge under earthquake, spatial analysis model was established to study the impact on the seismic behavior of Y - shaped irregular bridge concerning bearing friction sliding and structural pounding. The results showed that displacement at the top of the piers and internal force of piers reduced but the girders have a larger acceleration impulse, as taking bearing friction sliding and pounding of expansion joint into consideration. When the friction sliding and the structure pounding were not taken into account, the displacement of the top of fixed pier and the peak value of relative displacement of adjacent beams increase to a certain extent, however, there is no uniform law for the effect of the acceleration of girders. Under the action of longitudinal earthquake, the irregular Y - shaped bridge not only has a pounding along of the bridge, but also the pounding response of the transverse bridge can not be ignored. When calculating the seismic design of irregular bridges, the calculation model should be chosen to consider the friction sliding and the pounding between the structures.