基于可靠度和灵敏度的结构局部地震易损性分析

Local seismic fragility analysis of structures based on reliability and sensitivity

结构的地震易损性分析是结构地震风险分析的核心内容,传统的方法主要是分析结构的整体地震易损性。提出了结构局部地震易损性的概念,通过构造结构局部性能指标与其参数之间的一个新的功能函数,给出了局部地震易损性的可靠度表达式;根据可靠性灵敏度的概念,提出了构造结构局部性能指标概率密度函数的新方法,并详细推导了结构可靠指标对局部性能指标参数的灵敏度表达式。算例表明,所提方法可极大地提高结构地震易损性分析的计算效率。

Seismic fragility analysis is the central part of seismic risk evaluation of structures. In the traditional methods, the global seismic fragility is analyzed for structures. In this paper, a new concept, as local seismic fragility, is put forward. By constructing a new performance function which relates the local performance index with its parameter, the local seismic fragility problem is reformulated as a structural reliability problem. By way of the concept of structural reliability sensitivity, a new method for setting up the PDFs of the local performance index of structures is proposed. The sensitivity formulations of the reliability index with respect to the parameter of structural local performance index are derived in detail. It is demonstrated by a numerical example that the new method proposed herein can greatly improve the computation efficiency of seismic fragility analysis of structures.