考虑楼梯的框架结构连续倒塌分析

利用有限元软件SAP2000的动力非线性计算方法对考虑楼梯与不考虑楼梯两种情况下的框架进行连续倒塌计算,对比分析了楼梯位置处两处框架柱失效时框架的抗连续倒塌能力。分析结果表明:当楼梯部位的柱失效时,考虑楼梯与不考虑楼梯对框架的连续倒塌计算影响很大。考虑楼梯后,模型失效点处的位移和框架梁的内力减小,部分柱内力增大;楼梯构件受力改变,可能会因此失效,但有利于实现荷载的多路径传递,从而对框架的抗连续倒塌有利。

Progressive collapse analysis of frame structure with stairs

Using nonlinear dynamic method of finite element software SAP2000,the progressive collapse analysis was taken on frame in which the stairs were not considered(frame 1) and on frame in which the stairs were considered(frame 2).The resistance to progressive collapse of the frame was analyzed while two frame columns at the location of the stairs separately failed suddenly.It is shown that the results of progressive collapse analysis are significantly different between the frame 1 and the frame 2.Compared with the result of the frame 1,the displacement of the failure point and the internal force of the beam of the frame 2 decrease,however,internal force of some columns increase.Internal force of the stair components changes and the stair components may fail for this reason.At the same time,a new vertical load path is created due to the stairs,which is advantageous for the resistance to progressive collapse of the frame.