RC框架结构倒塌地震易损性评估

为系统评估RC框架结构的抗地震倒塌能力,按照中国现行规范设计了66个典型RC框架结构,基于OpenSEEs平台建立了考虑节点剪切变形的典型RC框架结构集中塑性铰模型,并采用IDA分析方法得到各典型结构的IDA曲线与倒塌点;分析设防烈度、层数及跨度对倒塌储备系数的影响,评估RC框架结构在大震及特大地震下的抗地震倒塌能力。结果表明:按中国现行规范设计的RC框架结构的抗倒塌储备系数CMR与设防烈度和层数存在负相关关系,而与跨度的相关性较弱;符合现行规范设计的RC框架结构满足大震不倒的设防要求,但其抵御特大地震作用的能力明显不足,其中,7.5度设防RC框架结构的抗倒塌能力最弱。

Seismic collapse fragility estimation of RC frame structures

In order to systematically evaluate the seismic collapse resistance of RC frame structures in China, 66 typical RC frame structures were designed in accordance with the current codes. Based on OpenSEES platform, the lumped plastic hinge model of typical RC frame structures considering shear deformation of joints was established. IDA curves and collapse points of typical structures were obtained by IDA analysis method. Furthermore, effects of building seismic fortification levels, storeys and span on the collapse margin ratio (CMR) were analyzed, and the seismic collapse resistance of the RC frame structure under major earthquakes and severe earthquakes was evaluated. The results show that, the CMR of the RC frame structure designed according to China''s current codes has a negative correlation with the seismic fortification levels and stories, but has a weak correlation with the span; the RC frame structure designed in accordance with the current code can meet the fortification requirements of major earthquake, but its ability to withstand the effects of severe earthquakes is obviously insufficient. Among them, the 7.5 degree fortified RC frame structure has the weakest ability to resist collapse.