Seismic performance of steel frame joint with dumbbell-type replaceable energy-consuming beam sections

Abstract This research proposes a steel frame joint that addresses the issues of low lateral stiffness and the difficult replacement of traditional flange weakening joints. The proposed solution involves a steel frame joint with dumbbell-type replaceable energy-consuming beam sections (DREBS). Using DREBS with weakened webs, rather than weakening the flanges, improves the overall lateral stiffness of beam sections and enhances resistance to out-of-plane deformation. The replaceable energy-consuming girder section of the joint is connected using high-strength bolts, making it more convenient to replace. In addition, more steel can be saved using a large girder section instead of the entire girder. This study investigates the seismic performance of the proposed connection by examining the effects of various parameters, including the weakening length and weakening depth of web. Stress–strain diagrams and hysteresis curves are compared and analyzed with the weakening length and weakening depth of web. Also, the initial rotational stiffness is investigated using the component method, and the error between the stiffness from the equation and that from finite element calculations was compared. The results show that the length and depth of web weakening affect the structural performance; the longer the weakening length of web and the greater the weakening depth of web, the stronger the structure. Recommended values for the weakening length of webs are 0.24 to 0.48 times the length of the “dumbbell” beam. Similarly, the recommended values for the weakening depth of web are 0.07 to 0.21 times the height of the “dumbbell” beam section. The relative error between the theoretical and finite element values is 6.9%.