基础隔震结构抗震可靠度简化分析方法

A Simplified Analysis Method for Evaluating Seismic Reliability of Base Isolated Structures

选用胡聿贤平稳地震地面运动模型作为基础隔震结构的随机地震动输入,采用Bouc-Wen模型描述隔震结构的层间滞变位移,将滞变体系动力特性矩阵随机等效线性化,并建立等价线性状态方程。引入左右特征向量系,对振动微分方程进行解耦,推导了基础隔震结构随机地震响应的统计矩解析解。采用变形失效准则,定义了上部结构和隔震层的功能状态极限函数。在此基础上,采用首次超越破坏模型,基于Possion分布假设和串联系统可靠度模型,建立了从整体上评价基础隔震体系抗震可靠度的简化分析方法。最后,通过一个基础隔震框架结构计算实例,说明了这种方法的运用。

A stationary power spectral model presented by Hu Yuxian is selected as a random earthquake excitation for base-isolated structures.The story hysteretic drifts of the base-isolated structures are described by Bouc-Wen model.The equivalent linearized state equation is established after equivalent linearization of dynamic property matrixes of hysteretic system.By introducing left and right eigenvector series,the vibration differential equation is decoupled and the analytical solutions of response statistical moments of structures are found.In accordance with the deformation failure criterion,the limit states of base-isolated structures are defined.On the basis of the first passage mechanism, the hypothesis about Possion distribution and the series connection reliability model,a simplified method for evaluating the seismic reliability of base-isolated structures on the whole is presented.Finally,a frame structure with base isolation is given for numerical illustration of the proposed method.