Innovative Technique for Strengthening Steel Frame Articulated Joints in Restricted Conditions

Upper space limitation problems such as floor slabs and decorative panels on the upper part of steel beams, cause difficulties in the actual strengthening OF steel structures. A new type of retrofitting method for articulated joints of steel frames under the limitation conditions was proposed. The models of articulated joints, rigid joints, and rectangular plate-strengthened joints were established. Finite element analysis was employed to investigate the failure modes, ultimate load-carrying capacity, hysteresis characteristics, ductility, energy dissipation capacity, and stiffness degradation of the joints. Additionally, the parameters of the new strengthened joint models are analyzed. It was found that the hysteresis curves of the strengthening joints were fuller and the bearing capacity and seismic performance were significantly improved, When the length-thickness ratio is less than 20, the bearing and energy dissipation capacities increased with increasing the rectangular strengthening plate size.