不同层隔震结构在近断层地震作用下动力响应分析

选用天然橡胶支座(LNR)与铅芯橡胶支座(LRB)作为两栋8层钢筋混凝土结构的隔震装置,对其分别输入172条近断层地震波,计算隔震层设置在基础或以上每一层时隔震结构的动力响应,分析近断层地震动对不同层隔震结构动力响应的影响。分析结果表明:隔震结构输入能量小于非隔震结构输入能量,LRB隔震结构的输入能量小于LNR隔震结构的输入能量;随着隔震层的上移,隔震支座位移减小,顶层最大加速度增大。近断层地震动特征参数与不同层隔震结构动力响应参数均存在相关性,但相关程度不同。隔震结构设计要根据建筑结构动力响应的需求,同时考虑隔震层位置与地震动特征参数的影响。

Analysis on dynamic responses of different story isolation structures to near-fault ground motions

The dynamic responses of two 8-story RC frame structures were studied respectively when the isolation layer was set in the base layer or each superstructure layer. The natural rubber bearings (LNR) or lead-rubber bearings (LRB) are adopted. 172 near-fault seismic records are input. The effect of near-fault ground motions on different story isolation structures is analyzed. The input energy of isolation structure is less than that of non-isolation structure. The input energy of LRB isolation structure is less than that of the LNR isolation structure. The maximum displacement of isolation bearing decreases and the maximum acceleration of top-story increases with the isolation layer rising. The characteristic parameters of near-fault ground motions are all correlated with the dynamic responses of isolation structures，but the degree of correlation is different. The isolated structures need to be designed in terms of the requirements of structure dynamic responses, meanwhile it should consider the position of isolation layer and the influence of seismic characteristic parameters.