中小跨径桥梁地震作用下横向损伤模式分析

Analysis of transversal seismic damage model under earthquake for small and medium span bridges

为研究横桥向地震作用下板式橡胶支座对桥梁抗震性能的影响,比较了传统延性抗震设计方法与考虑支座摩擦滑移抗震设计方法的差异,采用Open Sees软件建立桥梁有限元模型,对一简支变连续梁桥进行了非线性增量时程分析,对比研究桥梁支座、挡块和桥墩的受力性能,并根据延性系数对桥梁各构件的损伤顺序进行了分析。研究结果表明:按传统延性体系设计时,桥梁破坏首先从墩底开始,在大震作用下会造成墩底发生严重损伤;考虑支座摩擦滑移时,桥梁损伤首先是支座和挡块的破坏,然后是墩柱发生损伤,支座摩擦滑移后可大大减小传递到下部结构的地震力,大震下桥墩保持弹性或只发生轻微损伤,建议桥梁抗震设计时采用考虑支座摩擦滑移的抗震设计方法。

To study the transversal seismic performance of bridges with laminated rubber bearing under earthquake,by considering two different earthquake-resisting systems： the ductility and the beating friction sliding model, the OpenSees was used to establish the finite element model of a simply supported changing continuous girder bridge by incremental nonlinear dynamic analysis, compare the seismic performance of bridge bearing, shear key and pier, and analyse the damage sequence of bridges members based on ductility coefficient. Research results show that： when we designe the bridge by ductility method, the bottom of bridge pier is damaged first, it can bring serious damage to the pier, which would cause the whole bridges collapsed; when the bearing becomes nonlinear, the bearing begins to slip, the friction slipping consume to be the earthquake energy, the damage first appears at bearings and shear keys, then piers, and the friction and sliding at bearing can greatly reduce the inertia force to substructure, the pier remains elastic or only suffers slight damage, and it is suggested to consider bearing friction and sliding in bridge seismic design.