Investigating the influencing factors on the behavior of composite shear walls with an opening

Shear walls are widely used as lateral load-resisting systems in tall structures; however, reinforced concrete shear walls lead to excessive thickness and weight, while steel shear walls suffer from premature buckling and limited energy dissipation. To overcome these limitations, composite steel plate shear walls (CSPSWs), consisting of steel plates combined with concrete layers, have been introduced as an efficient alternative. In this study, a nonlinear finite element model of CSPSWs with openings was developed and validated against experimental results. The influence of key parameters including connector bar diameter and spacing, concrete compressive strength, thickness of the concrete core and steel plates, axial load ratio, and local reinforcement was investigated. The results indicate that bar diameter has negligible impact, while larger spacing reduces ductility. Increasing concrete thickness and compressive strength enhances buckling resistance of the steel plates, thereby improving overall seismic performance. Strengthening the lower portion of the wall improves stability only if it does not provide excessive restraint to the upper part, otherwise ductility decreases significantly. Openings reduce lateral resistance but increase ductility; reinforcing the corners mitigates stress concentration and improves performance. Comparisons show that CSPSWs with double steel plates and intermediate concrete exhibit higher strength and ductility than equivalent single-plate systems. Moreover, as plate thickness increases, the contribution of the concrete layer becomes less significant. Seismic performance parameters including behavior factor, overstrength factor, and displacement amplification factor were obtained through a combined methodology of pushover, incremental dynamic, and linear dynamic analyses. Overall, results demonstrate that CSPSWs provide an effective and economical lateral force-resisting system for high-rise buildings.