考虑轴力转移的并联基础隔震结构地震反应分析

在地震作用下,并联基础隔震结构的隔震层随着水平位移的增加,由于两类支座竖向刚度不同,将在两类支座间出现轴力相互转移,隔震层的力与水平位移的关系呈现很强的非线性关系。根据该种隔震结构不同类型支座间轴力在地震过程中相互转移的特点,给出并联基础隔震体系考虑轴力相互转移的隔震层恢复力模型,提出一种基于SIMULINK环境下对并联基础隔震体系考虑支座轴力相互转移进行仿真计算分析的新方法。工程实例计算结果表明,考虑支座承受的竖向荷载变化时,隔震层最大水平位移比不考虑支座竖向承载力变化时有所下降,支座竖向承载力变化所引起的附加摩擦力已经成为一个不能忽视的因素。

SEISMIC RESPONSE ANALYSIS OF PARALLEL BASE ISOLATION STRUCTURE CONSIDERING AXIAL FORCES SHIFT

Because the vertical stiffness of two kinds of bearings of parallel base isolation structures are different,the axial forces will shift when the displacement of isolation layer increases under earthquake loading;and the dynamic characteristic of isolation layer appears strong nonlinearity.According to the character of axial forces shift between two kinds of bearings under earthquake loading,the resilience model of isolation layer considering the vertical force is given;and the calculating model is studied too.A dynamic simulation method for the isolation system based on SIMULINK is put forward,in which the shift force between the rubber bearing and the sliding isolated bearing is considered.The results of an example show that the horizontal maximum displacement of isolation layer will decrease when the axial force transfer is considered.So the effects of additional friction forces caused by bearing vertical force transfer cannot be neglected.