Abstract：To accurately reflect the real state of all-welded joints in the collapse process of steel frame structures, the mechanism and analysis model of the all-welded joints were investigated under large structural deformation condition. Based on the accurate simulation of the experiment for all-welded joint, the mechanism and the deformation characteristics of all-welded joint in elastic-plastic stage were investigated, and the traditional component-based model of all-welded joint was improved. The static and dynamic nonlinear analyses of steel frame substructures with shell element model, improved component-based model of joint and ideal rigid model of joint were respectively carried out, and the influence of joint model on the progressive collapse resistance of steel frames was investigated. The results show that the shear deformation of the panel zone accounts for the main part of the all-welded joint deformation in elastic-plastic stage. The axial tension of beam not only weakens the strength of joint, but also reduces the ductility. The elastic-plastic behavior of all-welded joint during the progressive collapse of steel frames can be accurately simulated by the improved joint component-based model in the static and dynamic analyses.
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2020, Vol. 41 
