Seismic Behavior of Beam-Connected Precast Walls with Innovative Concealed Steel Bracings: Experimental Insights and Numerical Study

In order to improve the seismic performance of traditional precast lightweight walls, a new precast concrete wall with beam connection and embedded steel support is proposed in this study. Six 2/3-scale specimens were designed for a quasi-static cyclic loading test, and a numerical study was carried out. Key variables include shear span ratio (0.8–1.6), wall thickness (120–200 mm), concrete strength (C25–C40), and concealed column configuration. The experimental results reveal three distinct failure modes, specifically, brace buckling, weld fracture at the lower joints, and bolt shear failure. The system shows excellent ductility (displacement ductility coefficient μ = 3.2–4.1) and energy dissipation capacity (equivalent viscous damping ratio ξ = 0.28–0.35), and its performance is 30–40% higher than that of traditional reinforced concrete walls and close to that of steel plate shear walls. The shear span ratio is reduced by 50%, the shear bearing capacity is increased by 16%, but the peak displacement is halved, and the peak load of concealed column is increased by 57%. The finite element analysis verified the experimental trends and emphasized that the shear capacity can be increased by 12–18% by widening the steel brace (relative to thickening) under the condition of constant steel volume. The results demonstrate that BIM-driven design is very important for solving connection conflicts and ensuring constructability. Parameter research shows that when the concrete strength is greater than C30, the yield load increases by 15–20%, but the influence on the ultimate bearing capacity is minimal. These findings provide an operational guide for the implementation of high-performance prefabricated walls in earthquake-resistant steel structures, and balance the details of constructability through support, connection, and BIM.