山区多层接地隔震框架结构的抗震性能研究

Study on seismic resistance behavior of the mountain isolated frame structure connected with ground by not only the first floor

筛选来自台湾集集地震同一场地类别上的三个台站的地震波,包括两条近断层地震波TCU054与TCU068和一条远场波ILA007,引入多次透射边界以模拟场地的无限性,利用二次开发后的ANSYS建立考虑土-结构相互作用的山区多层接地基础隔震与层间隔震框架结构有限元模型,针对近断层地震动与远场地震动作用下山区隔震框架结构的位移、加速度、层间剪力与层间位移角等地震响应进行对比分析。结果表明:远场地震动作用下三种结构中位于陡坎上部楼层的层间剪力的相对关系均为非隔震>层间隔震>基础隔震,而两种隔震结构中位于陡坎下部楼层的层间剪力值很接近,与非隔震结构的相对关系与土体的刚度有关。多层接地框架的两种隔震形式均放大了掉层部分的层间剪力,但远场地震动作用下的放大效应比近断层地震动作用下的放大效应要低。两种隔震结构中位于陡坎上部的楼层在近断层地震动作用下的响应均大于远场地震动作用下的响应。

Three earthquake records from the Taiwan Chi-Chi earthquake on the same soil site are chosen,including two near-fault earthquake TCU068 and TCU054,and one far field earthquake ILA007. The fault distance of two near-fault ground motions are all less than 10 km,wich pulse motion of ground velocity is included in, and the distance of the far filed earthquake is more than 100 km.Based on mulitransmitting boundary and the ANSYS after secondary development, the SSI(soil-structure interraction) multilayer ground base isolation and story isolation building models were established. The earthquake response analysis was carried out on the two kind of buildings above under near-fault and far field ground motions.It is found that rich low frequency component is included in near-fault groud motions,which will cause adverse influence on long-period structure,and rich high frequency component is included in far filed groud motions,which will adversely effect on short-period structure. the earthquake response of SSI multilayer ground base isolation and story isolation buildings is greater under near-fault ground motions than far fied ground motions, and the damping effect of the isolation bearings under near-fault ground motions is poorer.