构件失效后钢筋混凝土框架结构倒塌响应特性分析

Response analysis of RC frame structures in progressive collapse after the member failure

利用OpenSees有限元软件,将抽柱法与有限元法相结合;并假定构件的局部失效位置,通过引入不同的结构参数,如结构的层数、层高、跨度等,分析了其对结构倒塌响应的影响;研究了结构在静力Pushdown分析和动力非线性分析条件下的结构倒塌响应特性。结果表明:柱失效位置对结构的静力Pushdown分析和动力非线性分析结果有较大影响,其中边柱的失效导致结构的抗倒塌能力明显降低,并在地震作用下随着失效点位移加大,振动规律也趋于不稳定;结构的极限承载力随着框架结构层数的增加而增加,极限位移和延性则随着层数的增加而降低,动力加载条件下结构失效位置的竖向位移随着层数的增加而增大;随着层高的增加,结构的极限承载力则逐渐降低,但对结构极限位移和延性的影响并不明显;跨度的增加使结构的极限承载力明显下降,延性略有降低,但极限位移和初始刚度却随之增加。以上规律性研究结果为钢筋混凝土框架结构的抗倒塌设计提供了必要的依据。

This paper adopts opensees finite element software as a tool, with its unique Remove command, by removing the reverse counterweight at the structure failure position the continuous collapse process of remaining structure under sudden failure of local components is simulated. By introduction of different structural parameters(such as structure storey number, storey height, span), the structural responses under static Pushdown analysis and dynamic nonlinear analysis are analyzed. The result shows the column failure locations have significant influence on the simulation results of structural responses under static Pushdown analysis and dynamic nonlinear analysis.The failure of external columns can cause a remarkable decrease of collapse performance meanwhile the displacement drift in the failure location under seismic load tends to be unstable. With the increase of structure storey number, the ultimate bearing capacity of structure and the vertical displacement in failure points under dynamic load increases, while the ultimate displacement and ductility decreases. With the increase of storey height,the ultimate bearing capacity of structure gradually decreases, while no obvious influence on the ultimate displacement and ductility is observed. The increase of span causes a significant decrease of the ultimate bearing capacity of structure and a slight decrease of ductility; however it leads to an increase of ultimate displacement and initial stiffness occurred. The above analysis has provided some necessary principles on the collapse resistance design of the reinforced concrete frame structure.