Beam–to–column joint solutions for reusable moment-resisting steel frames

Abstract

This paper advances reusable building practices by introducing an innovative beam–to–column joint for moment-resisting steel frames. The proposed joint, featuring T-stubs and cleats, is fully demountable, employing bolted connections instead of welds. Moreover, it is designed to accommodate reclaimed steel, incorporating an adaptable link that extends the service length of existing members and adjusts them to the required span of a new structure. Experimental testing was conducted on three test specimens to evaluate joint performance and identify failure modes, moment resistance, rotation capacity and stiffness. Two joint configurations were tested, varying the T-stub section and number of bolts on the T-stub web–to–beam flange connection. Additionally, the influence of material origin, reclaimed versus new steel, was investigated through two specimens with identical configurations. Testing revealed two failure modes: bearing deformation at bolt holes in the T-stub web and failure of the first bolt row on the column flange. Results also highlighted the critical role of bolt slip resistance on the T-stub web–to–beam flange connection in governing the rotational stiffness. Finite element models were developed and validated against the experimental results to simulate the mechanical behaviour of the joints. A parametric numerical study explored key design variables, including link length, bolt diameter, and number of bolts. The findings contributed to improving the joint structural performance by increasing its resistance and delaying the stiffness degradation. Results indicated that increasing the link length from 100 to 150 mm does not have a negative effect on the joint performance.