考虑碰撞效应曲线桥非线性响应及减隔震分析

Nonlinear Responses and Seismic Isolation Analysis of a Curved Bridge Considering Pounding Effect

目的研究陕西省镇巴县一座人字形曲线桥,展开相关受力性能分析,为此类桥梁的抗震设计提供设计参考。方法首先通过考虑桩-土相互耦合作用,建立了精细化的人字形曲线桥有限元模型,并与振动台试验的位移响应验证;基于直接积分法输入多向地震动,对比分析曲线桥在有无考虑碰撞效应下主梁、墩顶与墩底的力学性能;最后通过安装黏滞阻尼器进一步研究该曲线桥的减隔震性能。结果考虑碰撞效应,地震波输入方向为150°时碰撞力最大;随着伸缩缝宽度的增加,主梁间的碰撞力不断减小;主梁和墩顶受碰撞力影响位移皆明显减小,墩底内力则受碰撞力影响很小;黏滞阻尼器有效减小了桥梁的碰撞力与主梁位移,对提高人字形曲线桥的抗震性能有明显影响。结论地震波输入方向与伸缩缝宽度对主梁间的碰撞力影响明显,且人字形曲线桥在碰撞作用下主梁与墩顶易发生破坏,可以安装黏滞阻尼器限制主梁与墩顶位移。

A herringbone curved bridge in Zhenba County,Shaanxi Province is studied,and the relevant mechanical performance analysis is carried out to provide reference for the seismic design of such bridges.Firstly,a refined finite element model of the herringbone curved bridge is established by considering the pile-soil interaction.It is verified by the displacement response of shaking table test.Multiple direction ground motion input is used based on direct integration method,the mechanical properties of main girder,pier top and pier bottom of curved bridge with or without considering pounding effect were compared and analyzed.Finally,the seismic isolation performance of the curved bridge is further studied by installing viscous dampers.The results show that if considering the pounding effect,the pounding force is the largest when the input direction of seismic wave is 150°;with the increase of the width of the expansion joint,the pounding force between the main girder decreases;the displacement of the main girder and pier top is significantly reduced by the pounding force,while the internal force of the pier bottom is little affected by the pounding force;the viscous damper can effectively reduce the pounding force and displacements of the girder,which has obvious influence on improving the seismic performance of the herringbone curved bridge.The direction of seismic wave input and the width of expansion joint have obvious influence on the pounding force between main beams.The main girder and pier top of herringbone curved bridge are easy to be damaged under the pounding,and viscous dampers can be installed to limit the displacement of girder and pier top.