Steel frame collapse assessment method based on dynamic increase factor

To study the laws of evolution dynamic increase factors (DIFs), relationship between DIFs and progressive collapse resisting capacity a structure with web cleat joints under column removal scenario, refined finite element model is established based on an existing quasi-static test. The are studied for different loading type, beam height, joint rotation stiffness. It was observed that displacement-based factor (DIFu) increases in load level elastic elastic-plastic stages, it decreases plastic stage. With structural damage, DIFu reaches maximum value when frequency ratio equal to 1 further damping ratios. load-based (DIFp) negatively corelated “arch compression effect” beam. Finally, method proposed judging structures joints. In addition, improvement provided design joint. proved be reasonable effective help evaluation this study.