Analysis of the progressive collapse of space truss structures during earthquakes based on a physical theory hysteretic model

This study develops a force-displacement hysteresis model (computer program) for a bar element based on a physical theory model. The model is capable of capturing complex physical phenomena of member, such as yielding under tension, non-elastic buckling under compression, growth effect and degradation of buckling capacity due to the Bauschinger effect. The proposed element model is validated by comparing the simulation results with previous experimental results and is applied to the dynamic analysis of space truss structures. The explicit dynamic analysis method is adopted for solving the nonlinear equations of motion. Furthermore, a case study of a three-layer space truss structure is conducted. The reliability of the proposed algorithm and the need to develop the bar element are verified by comparing the results obtained using the proposed method and the ANSYS finite element analysis software package. Moreover, several fracture criteria for bar elements are defined and are used to analyse the progressive collapse of a space truss structure under seismic loading. The analytical results demonstrate that the selection of the fracture criterion for the bar members significantly affects the calculation of the collapse of the space truss structure under seismic loading. The strut buckling/softening-based fracture criterion can be used to relatively accurately evaluate the collapse resistance of a space truss structure under seismic loading. Finally, the collapse mode of a power transmission tower model under seismic loading is simulated. The simulation results are then compared with the collapse mode of a power transmission tower with a similar structure that collapsed during the Wenchuan earthquake. The simulation results agree closely with the observations, thereby verifying the reliability of the proposed algorithm.