强震作用下高层钢框架结构倒塌模式分析

Analysis on Collapse Modes of High-rise Steel Frame under Strong Earthquakes

为了研究高层钢框架结构在强震作用下的倒塌模式,在研究该类型结构动力特性的基础上,考虑结构构件的双重非线性和材料应变失效,利用有限元软件LS-DYNA对高层钢框架结构的倒塌进行了全过程的模拟。结果显示高层钢框架结构的破坏模式可以分为动力强度破坏和动力失稳破坏两种类型。同时得到如下结论:由顶点位移曲线和加速度时程曲线的波动幅度可以较为清晰的判断高层钢框架结构发生倒塌。以失效构件数量的比例作为指标可以区分动力强度破坏和动力失稳破坏,一般情况下,高层钢框架结构发生动力强度破坏时,失效构件比例较大;而发生动力失稳破坏时,失效构件比例相对较小。

In order to study the collapse modes of high-rise steel frame structure under strong seismic excitations,the model of the high-rise steel frame structure was constructed by LS-DYNA software,and the collapse processes were simulated based on the dynamic characteristics of the structure. The results show that the collapse modes of high-rise steel frame structures were divided into two types,with the first being dynamic strength failure and the other dynamic buckling failure. Meanwhile,some conclusions were obtained according to the collapse index analysis,that is,the collapse of the structure could be rather clearly recognized by the vertex displacement time-history curve and the fluctuation amplitude of the vertex acceleration time-history curve,and,the failure types could also be judged by the proportion of the failure components. Generally speaking,the failure components accounted for a great proportion in case of the dynamic strength failure,but the failure component was in a small proportion in case of dynamic buckling failure.