近场地震下隔震结构基底发生碰撞的鲁棒易损性曲线计算

用凸集模型模拟隔震结构参数(如刚度、质量、支座的屈服力和屈服后刚度等)的不确定性,而用随机模型模拟地震动输入的不确定性,提出了计算近场地震作用下在考虑双不确定性因素时隔震结构基底发生碰撞的易损性曲线计算新方法；提出了鲁棒易损性曲线的新概念,计算结果将给隔震支座力学参数的设计以及基底与限位墙之间空隙宽度的选取提供参考；通过计算实例中基底最大位移敏感度分析发现,上部结构的质量和隔震支座的力学参数(如屈服力、屈服后刚度等)对基底最大位移影响较大,而上部结构的刚度对其影响不大；此外,该文的研究内容也为考虑结构参数和输入地震动双不确定性因素的情况下,计算各类结构地震易损性曲线提供了一种新的思路和途径。

CACULATION ON ROBUST FRAGLITY CURVES OF BASE-ISOLATED STRUCTURE UNDER NEAR-FAULT EARTHQUAKE CONSIDERING BASE POUNDING

The structural uncertainties of base-isolations (i. e., structural stiffness, structural mass, yielding force and post-yielding stiffness of isolation bearing) are represented by a convex model, while structural input uncertainties are described by a stochastic earthquake ground motion model. A new method for calculating fragility curves of a base-isolated structure is presented, considering base pounding and double uncertainties under near-fault earthquake, and the new concept about robust fragility curves is introduced. The calculation results provide some references to how to select the mechanics parameters of isolation bearings and the size of the isolation gap. According to the sensitivity analysis of the maximum base displacement, the upper structural mass and mechanics parameters of isolation bearings (yielding force and post-yielding stiffness of isolation bearing) have a great influence on the base maximum displacement, while the influence of the upper structural stiffness is small. In addition, the paper provides a new way to calculate robust fragility curves of structures when structural uncertainties and earthquake input uncertainties are simultaneously considered.