基于长周期作用的大底盘基础隔震结构地震响应分析

Seismic Response Analysis of Base Isolation Structures with Large Chassis Based on Long-period Action

收集了273条地震动信息并进行滤波处理,筛选了近场普通、近场脉冲、远场普通和远场谐和4类地震动,利用ETABS软件建立了一个大底盘基础隔震结构的有限元模型,进行隔震和抗震模型在双向地震动作用下的时程分析。结果表明:长周期作用下基础隔震结构减震效果比普通地震动差;大底盘楼层的减震效果在长周期地震动下,较塔楼明显降低,设防烈度下层间位移角超限,罕遇烈度下隔震层位移超限;普通地震动下,隔震结构能够降低大底盘结构的平-扭耦合效应,但长周期地震动下,扭转响应增大,尤其在大底盘顶层;隔震结构与长周期地震动产生共振,导致隔震结构响应的增长幅度大于抗震结构。

In this paper,273 pieces of ground motion information have been collected and filtered to select two kinds of special long-period ground motions and near-field and far-field ordinary ground motions. A finite element model of base isolation structure with large chassis is established by using ETABS software,and the time history analysis of the isolation and seismic models under bidirectional ground motion is carried out. The results show that the shock absorption effect of the base isolation structure under the long period is worse than that of the ordinary ground motion. The shock absorption effect of the large chassis floor is significantly worse than that of tower building under long-period ground motion. The inter-story displacement angle under fortification intensity exceeds the limit value,and the displacement of isolation layer under rare intensity exceeds the limit value. Under ordinary ground motion,the isolated structure can reduce the flat-torsional coupling effect of the large chassis structure,but the torsional response increases under long-period ground motion,especially on the top of the large chassis;the isolated structure and the long-period ground motion resonate,resulting in a larger increase in the response of the isolated structure than the seismic structure.