Experimental study on out-of-plane flexural behavior of steel-concrete-steel composite walls

In this study, six steel-concrete-steel composite wall (SCSCW) specimens have been designed and manufactured, and their out-of-plane flexural behaviors under combined axial and horizontal loads are experimentally studied. The study parameters include the connector arrangement scheme and applied axial load. The effects of these parameters on the failure modes, experimental load-displacement curves, bearing capacities, ductility co-efficients, stiffness, energy dissipation capacities, and strain distributions of the specimens are analyzed. All specimens exhibit sectional flexural failure. The failure phenomena include the out-of-plane local buckling, concrete crushing, and welding fracture of the steel plates. These specimens show excellent ductility with an average ductility coefficient 2.27. The strength degradation coefficients of the specimens are >0.85. Increasing the number of connectors can restrict the local buckling of external steel plates, and the bearing capacities of the specimens are also improved. The connector arrangement scheme and axial load significantly influence the secant stiffness of the specimens during the initial stage of the experiments. When the connector arrangement schemes are identical, the higher the axial load, the better the energy dissipation capacity of the specimens. A simplified calculation model for the flexural capacity of SCSCWs is proposed considering the effects of local buckling and side plates, which has high accuracy and efficiency, and average ratio between the calculated and experimental peak loads is 0.96. A brief design example for the SCSCWs is provided to illustrate the design process considering the axial and out-of-plane loads.