Experimental Research on the Shear Performance of RSM Integrated Walls Considering Self-Tapping Screw Spacing

The RSM integrated wall， consisting of a steel frame encased by double-sided thin steel plates and filled with rigid polyurethane foam， represents a novel type of shear wall. However， current literature lacks comprehensive research on the shear performance of RSM integrated walls， especially concerning the impact of self-tapping screw spacing on performance. This paper aims to investigate the influence of self-tapping screw spacing on the shear performance of RSM integrated walls through experimental testing and numerical simulation， providing scientific insights and design guidance for practical engineering applications. To thoroughly examine the shear performance of RSM integrated walls， a finite element model was developed using ABAQUS software. To validate this model， two RSM wall specimens with different self-tapping screw spacings （75 mm and 150 mm） were subjected to monotonic loading and quasi-static loading tests. Experimental data， including load-displacement curves and load-lateral hysteresis curves， were collected to evaluate the walls’ behavior. By comparing finite element simulation results with experimental data， the model’s accuracy was preliminarily validated. Subsequently， this study was extended to include five different self-tapping screw spacings （50 mm， 75 mm， 100 mm， 125 mm， and 150 mm） to explore their influence on the shear performance of RSM walls. Findings from both experiments and simulations showed that reducing the self-tapping screw spacing significantly improved the initial stiffness， shear capacity， and energy dissipation capability of RSM walls. Comparative analysis revealed that smaller screw spacing strengthened the connection between thin metal plates and the steel frame， delaying tearing at self-tapping screws and allowing better performance of the thin metal plates. As the screw spacing decreased， the bearing capacity degradation coefficient increased， and the stiffness degradation curve became more gradual， indicating enhanced ductility. However， when the steel plates were damaged， the frame could not fully bear horizontal loads， leading to a rapid decrease in wall bearing capacity. Additionally， energy dissipation capacity was negatively correlated with screw spacing， while the equivalent viscous damping coefficient increased initially and then decreased as displacement grew， indicating minimal impact from changes in screw spacing. The findings suggest that reduced self-tapping screw spacing enhances the connectivity between thin metal plates and the steel frame， effectively delaying the rupture of the thin metal plates. This significantly improves the shear strength and initial stiffness of the wall. These results establish a theoretical foundation for optimizing the design of RSM integrated walls and hold significant value for engineering applications.