摘要
Pushover分析方法是逐渐得到广泛应用的一种评估结构抗震性能的简化方法,已被引入我国新的建筑结构抗震设计规范。侧向力分布的选取是结构Pushover分析中的一个关键问题,尤其高阶振型影响显著时其选取直接影响Pushover分析的结果。本文通过拟合规范反应谱,挑选了适用Ⅱ类场地的4条地震动记录和4条人工波,对比了典型地震动下非线性时程分析和采用5种不同侧向力分布的Pushover分析的5层、10层和15层钢筋混凝土结构在不同地震动强度时的反应。通过结构振型参与系数量化了各个结构的高阶振型的影响。研究发现,随着结构层数的增加和地震动强度的增加高阶振型的影响变大,侧向力的选取变得十分重要。本文对在高阶振型影响下钢筋混凝土框架结构的Pushover分析中侧向力的选取提出了建议。
Pushover analysis is a simplified method for structure seismic evaluation, which is extensively used gradually, and is recommended by the new national code of seismic design of buildings. The load pattern selection is one of the critical issues in pushover analysis, especially when the higher modes influence is important. In this paper, by fitting the norm response spectrum for the second soil site, eight typical earthquake records including four natural records and four artificially generated acceleration records are selected. Comparison between nonlinear time history analysis (NL-THA) employing eight typical earthquake records and pushover analysis (POA) using five typical load patterns imposed on three RC buildings is undertaken at various ground motions. By modal participation factors, the influence of higher modes is quantified. It is found that with the increase of floor and the intensity of ground motion, the higher mode influence is getting more important and the result of pushover analysis is very sensitive to load pattern. Suggestions about load pattern selection in pushover analysis (POA) are made when higher mode influence is found important.
出处
《地震工程与工程振动》
CSCD
北大核心
2004年第3期89-97,共9页
Earthquake Engineering and Engineering Dynamics
基金
国家"十五"科技攻关课题项目(编号:2002BA806B-4)
