【摘要】 概率地震需求分析是美国太平洋地震工程研究中心(Pacific Earthquake Engineering ResearchCenter,PEER)提出的新一代"性能化地震工程(Performance-Based Earthquake Engineering,PBEE)"理论框架的重要一环。传统的概率地震需求分析方法称为"云图法",这种方法针对确定性结构进行一系列地震动作用下的非线性动力分析,从而得到地震动强度参数与结构地震需求的"云图"。然而,传统的云图法只能考虑地震动的不确定性,而无法考虑结构的不确定性。为此,结合拉丁超立方体抽样技术,提出一种能综合考虑地震动不确定性和结构不确定性的改进云图法,并将传统的概率地震需求分析内容拓展为概率地震需求模型、概率地震需求易损性分析、概率地震需求危险性分析三个层次。以一榀五层三跨钢筋混凝土框架结构为例,分别采用传统云图法和改进云图法对其进行概率地震需求分析,得到了该结构的概率地震需求模型、地震需求易损性曲线和地震需求危险性曲线。分析结果表明:提出的方法可以有效地考虑地震动与结构的不确定性,避免不考虑结构的不确定性而低估结构的地震风险性。更多还原

【Abstract】 Probabilistic Seismic Demand Analysis(PSDA)has already become an important part of the newgeneration of Performance-Based Earthquake Engineering(PBEE)proposed by PEER.The commonly used nonlinear demand estimation method in PSDA is called "cloud analysis" procedure,in which a "cloud" of seismic-demand-intensity-measure pairs are generated when a deterministic structure is subjected to a suite of earthquake ground motion records.However,this method can only consider the record-to-record(RTR)variation in ground motions but not consider the randomness in structural properties.An improved cloud method based on Latin Hypercube Sampling(LHS)technique is proposed to consider the inherent randomness both in structures and ground motions.Furthermore,the contents of the traditional PSDA are extended to include three parts:Probabilistic Seismic Demand Model(PSDM),Probabilistic Seismic Demand Analysis(PSDFA)and Probabilistic Seismic Demand Hazard Analysis(PSDHA).A three-bay and five-storey RC frame structure is taken as an example,that is analyzed by applying the improved cloud method and the original counterpart respectively,and the PSDMs,the seismic demand fragility curves and seismic demand hazard curves are derived and compared by the two methods.It is shown that the improved cloud method proposed herein is able to efficiently take into account the inherent randomness both in ground motions and in structures.It is also demonstrated by this example that the risk analysis results without considering structural randomness will underestimate the potential hazard of structures in the future earthquake events.更多还原