极罕遇地震作用下多层RC框架结构抗震性能分析

Seismic performance analysis of multi-layer RC frame structures under extremely rare earthquakes

为研究极罕遇地震作用下多层RC框架结构的抗震性能,本文依据我国现行《建筑抗震设计规范》(GB50010-2010)分别设计了建筑类别为丙类、抗震等级为一、二、三、四级的4个典型多层RC框架结构,在有限元软件OpenSees中对其进行数值建模并通过对其他试验进行数值模拟验证了本文数值建模方法的合理性与实用性,在此基础上,采用Pushover分析方法及增量动力分析(IDA)方法,分别对4个抗震等级的多层钢筋混凝土框架结构在极罕遇地震作用下的抗倒塌性能进行了分析。结果表明:在极罕遇地震下,当结构的设防类别为丙类时,根据现行抗震规范所设计抗震等级为一、二级的RC框架结构不能满足规范提出的“大震不倒”的抗震性能要求;抗震等级为三级的RC框架不能完全满足规范提出的“大震不倒”的抗震性能要求;抗震等级为四级RC框架能满足规范提出的“大震不倒”抗震性能要求。由于各级框架结构的表现性能不一,因此,有必要在修订抗震规范时对极罕遇地震下结构的抗震性能进行更加深入的研究。

In order to study the seismic performance of multi-layer RC frame structures with different seismic resistance under the action of extremely rare earthquakes,this paper designs the seismic resistance grades of Grades I,II,III and IV according to the current Code for Seismic Design of Buildings(GB50010-2010).Four typical multi-layer RC frame structures are numerically modeled in the finite element software OpenSees and the numerical simulation of other experiments is carried out to verify the rationality and practicability of the numerical modeling method.On this basis,Pushover is adopted.The analytical method and the incremental dynamic analysis(IDA)method were used to analyze the collapse resistance of the multi-layer reinforced concrete frame structures with four seismic grades under extremely rare earthquakes.The results show that from the Pushover curve of the four frames,it is reasonable to choose the maximum interlayer displacement angle of 1/50 as the collapse point.Under the rare earthquake,the RC frame structure with the first and second grades of seismic resistance according to the current seismic code cannot meet the seismic performance requirements of the“big earthquake does not fall”proposed by the code;the RC frame with the third grade of seismic resistance exists.The possibility of meeting the seismic performance requirements of the“big earthquake does not fall”proposed by the specification is not met;the seismic grade is a four-level RC framework that can meet the seismic requirements of the“large earthquake does not fall”proposed by the specification.Due to the different performance of the frame structures at all levels,it is necessary to conduct a more in-depth study of the seismic performance of structures under extremely rare earthquakes when the seismic specifications are revised.