Progressive Collapse Analysis of Concrete-filled Steel Tubular Column to Steel Beam Connections Using Multi-scale Model

The multi-scale model which combined the fiber beam element with the fine element was used to investigate the progressive collapse performance of steel beam to concrete-filled steel tubular (CFST) column connections. By using the nonlinear static analysis method and taking into account the influence of the adjacent framework of joints, the resistance of progressive collapse, the failure modes and the stress distribution revealed the resistance mechanism of these joints during the process of progressive collapse. And the vertical displacement time history curves of joints which displayed the progressive collapse resistance demands of these joints were obtained by using the nonlinear dynamic analysis method. The relationship between resistance capacity and resistance demand of these joints were obtained by analyzing the nonlinear static analysis results and the nonlinear dynamic analysis results. These analysis results showed that the frame structure with these joints which enabled to form the resistance mechanism and new alternate path of unbalanced loads can prevent the occurrence of progressive collapse after the failure of column connected to joints. And the adjacent framework can improve the ability of anti-progressive collapse of these joints.