长周期地震动作用下隔震梁桥碰撞效应研究

Research on the collision effect of isolated girder bridges under long-period ground motion

以五跨一联设置铅芯橡胶支座与摩擦摆隔震支座的隔震连续梁桥为研究对象,通过建立三维空间有限元模型,分析探讨了在近场与远场长周期地震动作用下,伸缩缝刚度及伸缩缝宽度变化对两种隔震连续梁桥梁端碰撞效应的影响.研究结果表明:无论是远场长周期地震动作用亦或是近场长周期地震动作用下,伸缩缝宽度对结构最大碰撞力及中碰撞次数均有不同程度的影响,伸缩缝宽度越宽,最大碰撞力越小且碰撞次数也随之降低;伸缩缝刚度变化仅对结构的最大碰撞力有影响;对比两种隔震结构碰撞效应分析结果可知,FPB隔震结构的碰撞程度低于LRB隔震结构.

The isolated continuous girder bridge with lead rubber bearings （LRB） or friction pendulum bearings （FPB） was taken as the research object to analyze the collision effect under near-fault or far-fault long-period ground motion. The parameters analysis including the stiffness of expansion joint and width of expansion joint have been done based on the 3D FEM. The results show that whatever the type of long-period ground motion, it has different effect of width of expansion joint on the force and times of collision, and the force and times were decreasing with the increase of width of expansion joint. The changing of stiffness of expansion joint had effect on maximum collision force only. Compared with two isolated structures, the collision effects of FPB structure were lower than LRB structure.