大震下中间层隔震体系的随机动力可靠性分析

The Dynamic Reliability of Mid-story Isolation Structure under Seldomly Occurred Earthquake

建立了中间层隔震结构的非线性动力分析模型.用刚度退化Bouc-Wen模型描述钢筋混凝土框架的滞变恢复力;用非退化Bouc-Wen模型描述隔震层的恢复力.采用虚拟激励法计算结构的非平稳随机地震响应,在Poisson交叉过程假设下,求得了结构体系基于位移首超破坏准则的动力可靠度,并以实际工程为背景,分析了隔震层参数对中间层隔震结构的体系可靠度的影响.结果表明:采用中间层隔震技术后,隔震层上部结构的地震力水平较原结构降低了一度,且下部结构的动力可靠度也较不隔震时有所提高,合理的隔震层刚度和适当的隔震层阻尼可以明显降低中间层隔震结构在大震下整体倒塌的概率.

A non-linear dynamic analysis model of mid-story isolation structure was proposed, in which the Bouc-Wen model was adopted to represent the hysteretic restoring force of isolator, and the stiffness degrading Bouc-Wen model was used for the reinforced concrete frame. The pseudo excitation method was employed to calculate the non-stationary random seismic responses of the structure. Under the Poisson hypothesis, the dynamic reliability of the structure based on the first passage failure criteria was calculated, and the influence of isolator parameters on the system reliability of the mid-story isolation was analyzed. The results have indicated that the seismic effect level of the structure above the isolation level can be lowered by one degree, and the dynamic reliability of substructure will be increased when the mid-story isolation technique is introduced. The collapse failure probability can also be greatly reduced with reasonable isolation stiffness and appropriate isolation damping.