近断层双向水平地震作用下隔震结构地震反应

The seismic response of base-isolated structure under bi-directional earthquake action of near-fault ground motions

近断层地震动脉冲特性在2个水平分量上具有差异,采用平方和开方法分析了近断层脉冲地震动双向地震作用下基础隔震结构和组合隔震结构的隔震层位移,并与近断层脉冲单向地震作用进行了对比分析,结果表明:若仅地震动加速度峰值大的分量或2个方向分量均存在明显速度脉冲,则产生的隔震层位移大于单向地震动;若仅地震动加速度峰值小的分量存在明显速度脉冲,双向水平地震作用产生的隔震层最大位移值小于单向地震动。近断层脉冲地震作用下,相比于基础隔震结构,设置黏滞流体阻尼器的组合隔震结构可以在满足减震系数要求的同时减小隔震层位移。

The pulse characteristics of near-fault ground motion are different in the two horizontal components.The SRSS method is used to analyze the isolation layer displacements of a base-isolated structure and a composite isolated structure under bi-directional action of near-fault pulse-like ground motion.Compared with that under one-directional action,the results show that the displacement of isolation layer induced by two-directional earthquake action is greater than that by one-directional earthquake action if only the component with bigger peak acceleration or two horizontal components have distinct velocity pulse.While the displacement of isolation layer induced by two-direc‐tional earthquake action is less than that by one-directional earthquake action if only the component with smaller peak acceleration has distinct velocity pulse.Compared with base-isolated structure,the composite isolated structure with fluid viscous damper can satisfy the seismic decrease coefficient while reduce the displacement of isolation layer under near-fault pulse-like ground motions.