Research on Fire Induced Progressive Collapse of Steel Frame Structures Based on Static-dynamic Conversion Analysis Methods

To investigate the progressive collapse mechanism and the initial failure rule of multistory steel structures under fire conditions,the static-dynamic conversion analysis method was developed based on the predefined field and restart function of ABAQUS.Applying this staticdynamic analysis method,the failure process of a steel structure under local fire was simulated and the initial damage mechanism of multi-story steel structures caused by the damage of column was studied.The influence of restraint stiffness ratio and load level to the initial damage mechanism of steel structures under fire conditions and dynamic effect of the whole structures was analyzed.The study results show that the static-dynamic conversion analysis method is feasible and the dynamic amplification coefficient of the column initial damage lies from 1.2to 1.5.