Cover Plate Integration in Reduced Beam Section Connections: Stress Redistribution and Seismic Performance Enhancement

This study presents a comparative evaluation of four steel beam-to-column connection configurations: Conventional (CONV), Cover Plate (CP), Reduced Beam Section (RBS), and a hybrid Reduced Beam Section with Cover Plate (RBSCP), under cyclic loading conditions, with particular emphasis on hysteresis behavior and energy dissipation capacity. Finite element simulations were performed up to 6% story drift to evaluate each model’s performance against the seismic demand limits prescribed in ASCE/SEI 41-17. All configurations demonstrated adequate ductility for moderate to severe seismic events. The CONV connection underperformed in both energy dissipation and stiffness retention, producing narrower hysteresis loops and exhibiting earlier stiffness degradation. In contrast, the CP connection achieved the highest energy dissipation and moment strength at all drift levels, attributed to the increased flange stiffness from the cover plates. The RBS connection exhibited stable, wellbalanced hysteresis loops with slightly lower strength but effective energy dissipation, benefiting from the intentional relocation of the plastic hinge away from the column face. The RBSCP connection combined the advantages of strength and ductility, sustaining broad and stable hysteresis loops with minor asymmetry between the positive and negative directions. Although it did not surpass the CP connection in peak strength, the RBSCP connection offered a well-balanced seismic performance. Analysis of the cyclic hysteresis loops revealed distinct differences in stiffness characteristics and degradation behavior. These findings highlight the potential of hybrid configurations such as the RBSCP connection, with further geometric optimization recommended to enhance consistency and reliability.