复杂高层结构基于增量动力分析法的地震易损性分析

IDA-based seismic fragility analysis of a complex high-rise structure

增量动力分析法(Incremental Dynamic Analysis,IDA)是一种以动力弹塑性时程分析为基础的参数分析方法,计算结构在不同地震动强度作用下的响应,能够反映结构体系随地震动强度的变化,经历弹性、弹塑性直至倒塌的全过程性能。而建筑结构的地震易损性是指在不同强度地震作用下结构达到或超过某种极限状态的条件概率。因此,增量动力分析的结果提供了结构地震易损性分析所需的数据。本文在增量动力分析的基础上,结合地震易损性分析,提出基于IDA的地震易损性分析方法,并采用该方法对某复杂超限高层结构进行抗震性能评估,得出该结构在3个地震水准下,超越5个极限状态的概率。研究表明,基于增量动力分析的易损性分析结果,可为预测重大工程结构的地震破坏和损失提供有力的科学依据。

Incremental Dynamic Analysis（IDA） is a parametric analysis method that emerges in several different forms to estimate more thoroughly structural performance under seismic loads.It involves subjecting a structural model to one（or more） ground motion record（s）,each is scaled to multiple levels of intensity,thus producing one（or more） curve（s） of response parameterized versus intensity level and depicting the whole process of the structure from elastic to elastic-plastic until collapse.Seismic fragility analysis brings in fragility curves which are useful tools for showing the probability of structural damage due to earthquake as a function of ground motion indices.Results of IDA provide the data needed for producing fragility curves.In this paper IDA is combined with seismic fragility analysis and the IDA-based seismic fragility analysis method is proposed.A complex high-rise structure is taken as an example to illustrate the procedure.The probabilities of five limit states are exceeded for three given ground motion intensity levels,which are estimated,respectively.