连续倒塌现象中结构动态响应特性的分析

局部破坏引起的动力响应是影响建筑物发生连续倒塌的重要因素。基于改变传力路径法建立了连续倒塌动力分析模型,对结构遭受局部破坏后的振动特性进行研究,并分析了失效时间及材料特性对结构动力响应的影响。分析结果表明,竖向固有振型是连续倒塌中动力响应的主要参与振型;失效时间越短,结构最大竖向位移及惯性力越大;且失效时间小于竖向固有振型对应的自振周期时,动力响应受失效时间的影响最为显著;较高的材料屈服强度可有效降低结构的竖向振动位移,但也会引发底层柱承受较大的竖向惯性力;强化模量的改变对结构动力效应的影响并不显著。

Dynamic response analysis of a frame structure in progressive collapse phenomena

Dynamic response caused by local damage plays an important role in the progressive collapse phenomena. The model for dynamic progressive collapse analysis was constructed based on alternate load path method. Studies were carried out to investigate the characteristic of vibration after local damage, and then the effect of failure time period and material characteristic on the structural response were analyzed. The results show that the vertical natural mode is the major contribution to structural vibration after local damage, and the maximum vertical displacement and inertial force decrease with the increase of failure time period; when the period of failure time is less than the structural nature period of vertical mode, the effect of failure time on structural vibration is obvious; as the yield strength increases, the vertical displacement decreases, and the inertia force increases which causes a higher axial force in the column of ground floor; the variation of strain harden has less effect on the vibration response.