近断层脉冲型地震动作用下隔震结构地震反应分析

隔震结构在远震场地减震效果良好，但是近断层地震动的明显的长周期速度和位移脉冲运动可能对隔震建筑等长周期结构的抗震性能和设计带来不利影响，需要深入探讨。本文首先讨论近断层地震动的长周期脉冲运动特征，然后以台湾集集地震8条典型近震记录和其它4条常用近震记录以及4条远震记录作为地震动输入，对两幢安装铅芯橡胶隔震支座的钢筋混凝土框架隔震结构进行非线性地震反应时程分析，通过比较探讨了算例计算结果，定量说明隔震结构的近震脉冲效应显著，是隔震设计不容忽视的问题。

Seismic analysis of base-isolated structures subjected to near-fault pulse-like ground motions

In the far-field region, the seismic response of the base-isolated structure can be reduced significantly. However, the distinct long-duration pulse motion of ground velocity and displacement in the near-fault region may cause the adverse influence on the seismic performance and design of the long-period structure including the base (isolation) building, which needs to be investigated deeply. In the present paper, the characteristics of long-duration pulse-like near-fault ground motions are discussed firstly. Then, eight near-fault (two groups) earthquake records from the Taiwan Chi-Chi Earthquake (Sep., 21,1999), four common near-fault (one group) earthquake records and four far-field (one group) earthquake records are selected as the input of ground motions, and the seismic response of two multi-story RC base-isolated frame structures with lead-core rubber bearings is obtained using nonlinear time history analysis. The numerical results of the base-isolated structures under four groups of earthquake records are compared, and it is illustrated quantitatively that the near-fault pulse-like effect on the base-isolated structures is remarkable, which cannot be neglected in the structural design of base-isolated buildings.