Structural performance of bolted HSS-to-HSS connections with reinforcement technique

Modular houses play a crucial role in addressing housing shortages, especially in emergencies and remote regions. This study examines the mechanical performance of three reinforcement techniques for Hollow Structural Section (HSS) connections in panelized modular houses: stiffeners beneath the extended plate, concrete filling within the HSS column, and a combined technique integrating both methods. A total of 162 finite element models were created via LS-DYNA software and validated using experimental results. This analysis focuses on ultimate moment capacity, ultimate rotation, failure modes, and the effectiveness of these reinforcement techniques in enhancing connection rigidity. The results demonstrate the significant influence of plate thickness, bolt arrangements, and reinforcement techniques on connection performance. Plates with a thickness of 8 mm are prone to premature tensile rupture, which can be mitigated using stiffener reinforcement. For the AR1.5 bolt arrangement, concrete reinforcement proved most effective, increasing capacity by 1.45 times the plastic moment, while stiffener reinforcement was the least effective. In contrast, for the AR0.6 arrangement, stiffener reinforcement induced local buckling in the column, whereas concrete reinforcement prevented it but increased ultimate rotation. A combination of reinforcement techniques is recommended for optimal performance, achieving the highest capacity of 2.2 times the plastic moment of the beam and reducing ultimate rotation by 76 % compared to concrete reinforcement alone. Design charts are proposed to predict failure modes by altering design parameters and are validated with tested specimens. The findings provide valuable insights for designing more efficient HSS connections in modular construction, improving structural integrity. • Evaluation of three reinforcement methods for HSS connections in modular houses. • Conducting a parametric study for different bolt and plate configurations. • Analysis of moment capacity, rotation, and failure modes of reinforced connections. • Design charts developed to predict failure modes for different configurations.