地震作用下Benchmark基础隔震结构支座破坏危险性评价

Hazard Assessment of the Isolation Bearing Failure in the Benchmark Base-isolated Structure Subjected to Earthquake Ground Motions

以Benchmark基础隔震结构为分析对象,用凸集模型模拟隔震结构参数(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,在PEER(太平洋地震工程研究中心)提出的以全概率理论为基础的基于性能的结构抗震评价方法(称为第二代PEBB)的大框架下,提出了计算地震作用下在考虑双不确定性因素时隔震结构支座发生破坏的危险性评价新方法。通过计算对比可知,若不考虑结构参数不确定性将低估隔震支座破坏的危险性;对计算实例中基底最大位移敏感度分析发现,隔震支座的力学参数(支座刚度、摩擦系数等)对基底最大位移影响较大,上部结构质量的影响次之,而上部结构的刚度对其影响不大。此外,该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,计算各类结构地震破坏危险性评价提供了一种新的思路和途径。

An analysis was performed on the Benchmark base-isolated structure using a convex model to simulate the uncertainties of the isolated structural parameters （e. g. , the stiffness, mass, post-yield strength and post-yield stiffness of the bearing） and a random model to simulate the uncertainties of the seismic input. Under the framework which is based on a full probability theory （also called the 2nd generation of PEBB） proposed by the Pacific Earthquake Engineering Research Center （PEER）, a new method for hazard assessment of bearing rupture in the isolated structure when considering the above two uncertainties are presented. A comparison of the calculations shows that failure hazard of an isolated bearing structure would be underestimated if the uncertainties of the structural parameters are not considered. The analysis on the maximum base displacement sensitivity in the actual calculation demonstrates that the mechanical parame- ters of the isolation bearing （the bearing stiffness, friction coefficient） have most significant impact on the maximum base displacement, the super structure mass impact is next, and the stiffness of the super structure stiffness impact is insignificant. Additionally, we also provided a new idea and approach for hazard assessment of different type of structures subjected to earthquake ground motions when considering the uncertainties of both the structural parameters and seismic input.