A SIMPLIFIED ANALYSIS METHOD ON PROGRESSIVE COLLAPSE OF STEEL-FRAME BUILDING UNDER INTERNAL EXPLOSION

At present, General Services Administration (GSA) standard method is widely used for reference to analyze progressive collapse of buildings. However, the criteria of collapse evaluation of this method are found inapplicable in China. Although the loading on structure caused by air shock wave and the damage failure of structural members are considered in explosive incentive simulation analysis method, it is hard to apply in practical engineering due to its computational complexity. In this paper, a simplified progressive collapse analysis under explosive loading is developed by utilizing the simplified explosive loading to take account of the impact on structure members caused by air shock wave, by applying nonlinear beam element taking account of strain rate effect to structural members, by adopting the method of killing failure element to take account of structural members failure, and by setting contact elements among structural members and contact elements between structural members and the ground surface to take account of the interaction and load transfer behavior of structural members in the process of progressive collapse. After comparing with the explosive incentive simulation analysis method, it is found that the simplified method proposed in this paper offers reasonable collapse process, reliable calculation results and response of structure under the impact of explosive loading, and it also greatly reduces computational requirements.