基于时域显式随机模拟的隔震结构易损性分析研究

工程结构的地震易损性分析结果是结构抗震性能评价和地震灾害评估的重要依据,考虑地震激励的非平稳随机过程本质,采用随机振动方法来进行易损性分析更具合理性。针对带隔震基础的多层结构,提出基于时域显式随机模拟的隔震结构易损性分析方法。首先建立求解局部非线性运动方程的显式降维迭代列式,继而与随机模拟相结合,求解层间位移和隔震层位移的首超概率,最终考虑不同地震动强度得到隔震结构易损性曲线。算例结果表明,相比于传统蒙特卡罗方法,基于时域显式随机模拟的方法具有一致的计算精度和明显更高的计算效率,有利于隔震结构易损性分析的工程应用。

Fragility analysis of isolated structures based on explicit time-domain random simulation

Seismic fragility analysis of engineering structures is an important basis for seismic performance evaluation and seismic hazard assessment. Considering the non-stationary random process nature of seismic excitation, random vibration-based method is more rational for the fragility analysis. For base-isolated multi-story structures, a random simulation method using explicit time-domain formulation is presented for fragility analysis of isolated structures. Firstly, an explicit dimension-reduced iterative formulation is established for solving the motion equation with local nonlinearity. Then the formulation is integrated into a random simulation to calculate the first-passage failure probability of the displacements of the inter-layer and isolation layer. Finally, the fragility curve of the isolated structures is obtained by considering different ground motion intensities. Numerical results show that, in comparison to the conventional Monte Carlo method, the proposed explicit time-domain random simulation method has similarly satisfactory accuracy and significantly higher computational efficiency, favoring the engineering application of fragility analysis of isolated structures.