基于随机IDA的钢框架核心筒易损性分析

Vulnerability Analysis of Core Frame of Steel Frame Based on Stochastic IDA

地震中的人员伤亡主要由于建筑物的倒塌所造成,合理评价建筑结构的抗震性能,有效分析结构的易损性,可以有效地减少人员损伤.由于钢框架的变形与混凝土核心筒存在较大差异,因此对于钢框架与混凝土核心筒的混合结构体系,如何评价其破坏程度存在较大难度.在混合结构中不同体系的损伤次序通常有先后之分,结构设计之初的设防理念是设置多道防线,保证主体结构在地震作用下不发生倒塌破坏,导致不同结构体系参与整体结构抗震的贡献在不同计算模型之间差异显著.为有效评价混合结构的地震易损性,文章提出,以弹性状态下2种体系所受剪力的比例关系为依据,对2种结构体系各自赋予不同的权重系数,建立混合结构体系的整体损伤模型,从而对混合结构的损伤极限状态进行量化.采用随机IDA方法对结构进行易损性分析,同时考虑结构的不确定性,分析钢框架混凝土核心筒结构在非倒塌与倒塌状态下的损伤破坏概率.

The casualties in the earthquake are mainly caused by the collapse of buildings.It is necessary to evaluate the seismic performance of the building structure and analyze the vulnerability of the structure.Due to the large difference in the deformation ability between the steel frame and the concrete core tube,it is difficult to describe the mixed structure of the steel structure of the steel frame concrete core tube under the earthquake.In the mixed structure,the damage order of different systems is usually different.The fortification concept at the beginning of structural design is to set up multiple defense lines to ensure that the main structure will not collapse under earthquake action,resulting in significant differences in the contribution of different structural systems to the overall structural earthquake resistance between different calculation models.In order to evaluate the damage degree of steel core structure under the action of earthquake,it is proposed that the ratio of the shear forces of the two systems under the elastic state is given to different weight coefficients of different structural systems.The whole damage model of the mixed structure system is established,and the damage limit state of the hybrid structure is quantified.The stochastic IDA method is used to analyze the structural fragility,and the uncertainty of the structure is considered.The damage probability of the steel frame concrete core tube under the condition of non-collapse and collapse is analyzed.