摘要
选取按照现行规范设计的既有建筑进行有限元建模,考虑地震动的不确定性对其进行大量增量动力分析(IDA),得到模型的IDA曲线簇。在此基础上对其进行地震需求概率分析和概率抗震能力分析,拟合得到结构的易损性曲线,据此对结构的倒塌概率进行定量评估,并比较基于非线性分析与性能评估软件PERFORM-3D的纤维模型和塑性铰模型的分析结果。结果表明:按照我国现行规范设计的钢筋混凝土(RC)框架结构,在预期的罕遇地震作用下倒塌概率较小,可满足"大震不倒"的要求;基于PERFORM-3D的截面纤维模型所得的RC框架结构,经非线性分析所得的倒塌概率相对保守,安全储备更高。
Performance-based seismic design theory has received considerable attention from scholars since its proposition in the 1990 s.Collapse evaluation is an important part of performance-based seismic design.In this respect,although current Chinese seismic design codes for building structures have particular requirements and analytical approaches are used to prevent building collapse,they do not provide a quantitative index for the collapse-resistant capacity.Therefore,the collapse-resistance performance of structural systems,the seismic fragility,and collapse capacity of a reinforced concrete（RC）frame structure were investigated based on incremental dynamic analysis.A five-story and three-bay reinforced concrete frame structure,which was designed based on the current Chinese codes,was selected as a study case to conduct a seismic fragility assessment and collapse evaluation.Considering the uncertainty of ground motion,a mass incremental dynamic analysis was conducted for an existing building based on the current codes.In the incremental dynamic analysis,the intensity of a single motion was increased according to a series of intensity measures,under which an elastic-plastic dynamic analysis was performed.The relationship between the engineering demand parameters and the intensity measures was thus obtained,and on the basis of incremental dynamic analysis curves,the seismic demand probability and seismic capacity were then established.Furthermore,collapse evaluation was quantitatively performed based on fragility curves,which enable an estimation of the possible damage to buildings that could occur during an earthquake and have important significance in the improvement of seismic capacity and disaster prevention mitigation work.Finally,a comparison was made between a fiber model and a plastic hinge model based on PERFORM-3D.The fragility curves provide a quantitative evaluation under a specific ground motion intensity,and results show that RC frames designed in accordance with the current code have a small collapse probability during a rare earthquake,and that they meet the requirements of a 3-level design.The fiber and plastic hinge models have similar performance at a low spectral acceleration of motion;however,differences between the two models were evident with an increase in the spectral acceleration.Based on the fiber model,a nonlinear simulation of the RC frame in a collapse evaluation was relatively conservative and had a higher safety margin compared to the plastic hinge model.Therefore,in consideration of efficient modeling,the fiber model provided by PERFORM-3Dis a better choice as compared to the plastic hinge model.
出处
《地震工程学报》
CSCD
北大核心
2015年第4期1060-1065,1072,共7页
China Earthquake Engineering Journal
基金
国家自然科学基金项目(51278402
51078305)
长江学者和创新团队发展计划(PCSIRT)
关键词
框架结构
增量动力分析
易损性分析
倒塌性能评估
frame structure
incremental dynamic analysis
fragility analysis
anti-collapse performance evaluation
