Dynamic Progressive Collapse Simulation Analysis Of Long-span Steel Station Structure

Currently the progressive collapse design method of structures is mainly based on the regular frame in domestic and abroad, however it is not based on the long-span complicated steel station structure. It is difficult to accordance with the fact if static analysis method is used for calculating the progressive collapse of steel station structure. In this paper, dynamic progressive collapse simulation of long-span railway station structure is studied by using software ANSYS/LS-DYNA in order to search for the collapse mechanism.Firstly, the key columns of the project were selected using the average stress ratio method and energy method. Secondly, the equivalent load transient unloading method is used to dynamic simulation analysis of different defective structures, single column failure structure or double columns failure structure, furthermore the judgments of the collapse performance and comparison of upper structure layer and lower structure layer of each defective structure are obtained. Finally, the influences of material failure strain, equivalent load failure time, damping ratio are studied to the structural collapse.The studies show that, this project has good redundant degrees and performance of resisting progressive collapse, the double middle columns failure is more disadvantage to lower structure layer, while the double side columns failure is more disadvantage to upper structure layer. The parametric analysis of this project show that the changes of material failure strain between the elastic limit and plastic limit have little effect on the progressive collapse of single side column failure. The equivalent load failure time takes 1 /10 of the first vertical self-vibration period of the defective structure is the most reasonable value. The changes between the range of general damping ratio of steel structure have little effect on the collapse performance of the project.