捏拢效应与P-Δ效应对地震延性需求和损伤指标的影响  

Influences of pinching and P-Δ effects on seismic ductility demand and damage index

作　　者：余波[1,2] 刘陶钧[2] 洪汉平[2] 

机构地区：[1]广西大学土木建筑工程学院,广西南宁530004 [2]西安大略大学土木与环境工程学院

出　　处：《地震工程与工程振动》2011年第4期94-105,共12页Earthquake Engineering and Engineering Dynamics

基　　金：中国留学基金委研究生专项(2008666001);中国留学基金委建设高水平项目(2009612007)

摘　　要：文中定量地分析了捏拢效应和P-Δ效应对非弹性单自由度体系的地震延性需求和Park-Ang地震损伤指标的概率统计特征的影响。采用Bouc-W en模型描述具有P-Δ效应、捏拢效应、强度退化、刚度退化等典型特性的恢复力-位移滞回曲线;根据非弹性单自由度体系在69条强震记录作用下的动力响应,定量地分析了捏拢效应和P-Δ效应对地震延性需求和Park-Ang地震损伤指标的均值和变异系数的影响,并建立了地震延性需求的概率预测模型。计算结果表明,捏拢效应和由重力引起的P-Δ效应对地震延性需求的影响较大,而由竖向地震激励引起的P-Δ效应对地震延性需求的影响很小;对于短周期体系,建议采用对数正态或Frechet分布来描述地震延性需求的概率分布;对于长周期体系,采用Frechet分布则更为合理。Assessment of the influences of pinching and P-Δ effects on seismic ductility demand and Park-Ang seismic damage index of inelastic single-degree-of-freedom（SDOF） system is carried out.The hysteretic behaviour of the SDOF system is described using the Bouc-Wen model taking into account strength and stiffness degradations as well as pinching and P-Δ effects.Analysis results show that the P-Δ and the pinching effects influence the seismic ductility demand,while the effect induced by the vertical excitation is negligible.Probabilistic models for predicting the mean and coefficient of variation of seismic ductility demand considering the pinching and P-Δ effects are recommended based on the samples obtained from 69 California records.It is suggested that for short-period system,the seismic ductility demand can be modeled as either the Lognormal or the Frechet distribution,while for long-period system,the Frechet distribution is preferred.

关 键 词：捏拢效应 P-Δ效应 地震延性需求 Park-Ang地震损伤指标 BOUC-WEN模型 

分 类 号：P315.959[天文地球—地震学]