L形平面钢筋混凝土框架连续倒塌分析

Progressive collapse analysis of L-shape plane reinforced concrete frame

为研究楼板对L形平面钢筋混凝土框架的影响,以某小学教学楼为背景,基于拆除构件法建立四种工况下的有限元模型,采用非线性动力分析方法,探讨四种工况下不加楼板与加楼板模型抗连续倒塌性能。结果表明:对于不加楼板模型,除底层内柱外,其余三种工况均会引起结构的连续倒塌且底层外角柱失效时更加显著;对于加楼板模型,只有底层外角柱失效才会造成结构的连续倒塌,需要重点加强。最后,通过分析子结构在梁机制和悬链线机制作用下的变形模式,提出以比较不平衡荷载做功与子结构耗能来评价结构是否发生倒塌的方法。

In order to research the effect of floors on L-shape plane reinforced concrete frame structures,a teaching building of a primary school is taken as the background.Based on the alternative path method,a finite element model under four conditions is established.By using nonlinear dynamic analysis method,the performances of resist progressive collapse of pure frame model and frame model with floors are analyzed.The results show that,for the pure frame model,except for the inner column,the other three conditions will cause the progressive collapse of the structure,and the failure of the outer corner column is more obvious; for the frame model with floors,only the bottom corner column failure will cause progressive collapse of the structure,so it needs to be strengthened.Finally,through the analysis of deformation modes in beam mechanism and catenary mechanism,a method is put forward to evaluate whether the structure collapsed by comparing the unbalanced load acting and substructure energy consumption.