THE PROGRESSIVE COLLAPSE ANALYSIS AND NUMERICAL SIMULATION BASED ON SENSITIVITY OF STEEL TOWER STRUCTURE

By introducing the sensitivity index proposed by Pandey, the method of identifying the key members of the structure is put forward. Based on the alternate load path method, the progressive collapse analysis of the steel tower structure under wind load was conducted by 4 different methods: linear static analysis, nonlinear static analysis, linear dynamic analysis, nonlinear dynamic analysis. The results show that the structural dynamic response depends on the direction of wind load and the position of key members, and linear static analysis is conservative while nonlinear dynamic analysis is more precise. It is recommended that nonlinear dynamic analysis should be taken to assess the progressive collapse of steel tower structure. Through unloading the equivalent force of failure element, the dynamic process of progressive collapse of steel tower structure was simulated. The computational methods of the initial duration t₀ (considering initial state) and unloading time t_p for equivalent force are presented.