Progressive collapse analysis of steel frame structures using flexibility-based element

Based on the flexibility method, whole process simulation for the progressive collapse of steel frame structures was conducted using OpenSees. Flexibility-based element was adopted to divide beam and column into four parts to achieve the fracture simulation of member. Based on the removing column method, the analysis procedure of structural progressive collapse was proposed. Two 6-storey steel frame examples were given to analyze the time history of failed nodal displacement and the sequence of members' plastic hinges and fractures. It is indicated that plastic hinges first appear in the ends of beams near the failed column. Member fracture in the beam ends is the main cause of collapse of the whole frame. The proposed method is verified by the results from ABAQUS software package and experiments. It can be applied to practical engineering in future. ©, 2015, Southeast University. All right reserved.