不同底部层高的RC框架结构地震易损性分析

Seismic vulnerability analysis of RC frame structures with different bottom heights

为研究不同底部层高的钢筋混凝土框架结构的易损性,应用SAP2000软件,采用动力增量分析法分别对设防烈度为7度和8度区6个不同底部层高的框架结构在地震作用下进行了非线性时程分析,得到了地震易损性曲线和结构在极限状态下的地震动强度指标,经回归拟合得到了不同设防烈度区的结构的失效概率公式和结构倒塌储备系数(CMR)。研究表明:结构在弹性阶段的耗能能力较差,在弹塑性阶段表现出较好的延性耗能能力。同一抗震设防烈度的RC框架结构倒塌储备系数CMR随着底部层高的提高而线性降低,底部层高较高框架结构的抗地震倒塌能力与底层层高负相关,基于IDA方法得到了不同底部层高RC框架结构的失效概率计算公式和抗倒塌储备系数线性拟合公式,可供工程设计参考。

In order to study the vulnerability of reinforced concrete frame structures with different bottom floor,SAP2000 software was used and the dynamic incremental analysis method was used to analyze the fortification intensity of 6 different bottom floor frame structures with 7 degrees and 8 degrees under earthquake action.Non-linear time history analysis was performed to obtain the seismic vulnerability curve and the ground motion intensity index of the structure in the limit state.After regression fitting,the failure probability formula and the structural collapse reserve coefficient(CMR)of the structure in different fortification intensity areas were obtained.).Research shows that the structure has poor energy dissipation capacity in the elastic stage,and exhibits good ductility energy dissipation capacity in the elastic-plastic stage.The collapse reserve coefficient CMR of the RC frame structure with the same seismic fortification intensity decreases with the increase of the bottom story.The seismic collapse resistance of the frame structure with the higher bottom story is negatively related to the bottom story.Based on the IDA method,different bottom story heights are obtained.The calculation formula of failure probability of RC frame structure and the linear fitting deduction formula of anti-collapse reserve coefficient can predict and evaluate the seismic performance of the same type of frame structure,which has certain guiding significance for the work of designers.