层间组合隔震结构随机动力可靠度分析

摘要

In order to limit the drift of the isolation layer under major earthquake, an inter-story hybrid isolation system with adding viscous dampers in isolation layer is proposed.The restoring force characteristics of the isolation layer and other floors are simulated by Bouc-Wen and stiffness degrading Bouc-Wen models, respectively.The motion equation of the hybrid isolation system is established.The pseudo excitation method is used to calculate the stochastic seismic response of the inter-story hybrid isolation structure.Then, the statistical quantity of the maximum drift of each story is obtained.The maximum drift of isolation layer and other floors are adopted as the control index to establish the limit state equation.The dynamic reliability of the structure is derived by using JC method and taking the stories as series mode.The total failure probabilities of inter-story hybrid isolation and inter-story isolation structures are compared with that of the fixed base structure through a numerical example.Finally, the influence of viscous damper parameters on the dynamic reliability is studied by changing the velocity index and viscous damping coefficient.The analysis results indicate that the total failure probability of inter-story hybrid isolation structure is lower than those of inter-story isolation and non-isolation structures.When the viscous damping coefficient is constant, with decreasing the velocity index decreases, the total failure probability becomes lower.When the velocity index is constant, the total failure probability decreases at first and then increases with the viscous damping coefficient increases, and the main failure mode is also changed from isolation layer to superstructure.%为了限制隔震层在大震作用下的层间位移, 基于在隔震层增设黏滞阻尼器的层间组合隔震体系, 分别采用刚度非退化和退化的Bouc-Wen模型模拟隔震层及其他楼层的恢复力特性, 建立了层间组合隔震结构在大震作用下的运动方程, 运用虚拟激励法对该体系进行随机响应分析, 得到了隔震层及其他各层层间响应峰值的统计量.以隔震层和其他各层的最大层间位移作为控制指标, 建立极限状态方程, 采用当量正态化法 (JC法), 基于串联模式计算了体系的动力可靠度.通过数值分析, 比较了层间组合隔震、层间隔震与非隔震结构的总体失效概率.最后通过改变黏滞阻尼器的速度指数和黏滞阻尼系数, 系统地研究了黏滞阻尼器参数对层间组合隔震结构动力可靠度的影响.结果表明:层间组合隔震结构的总体失效概率比层间隔震结构和非隔震结构都要低.当黏滞阻尼系数不变时, 速度指数越小, 结构的总体失效概率越低;当速度指数不变时, 随着黏滞阻尼系数的增加, 结构的总体失效概率呈现出先减小后增大的趋势, 结构的主要失效模式也逐渐由隔震层过渡为上部结构.