Interaction equations of composite walls with T-section under axial compression and biaxial bending

Abstract This paper studies the load-carrying capacity of concrete-infilled double steel corrugated-plate walls with T-section (T-CDSCWs) under axial compression and biaxial bending. T-CDSCWs are composed of flange and web walls and boundary elements. The T-section is mono-symmetric and exhibits different interaction curves of load-carrying capacity when subjected to axial load and different direction bending. Based on the finite element (FE) model established by the previous study, the local buckling of the steel corrugated-plates is considered in the load-carrying capacity. Subsequently, this paper investigates the behaviours of T-CDSCWs under axial compression and uniaxial bending, including stress distribution, load–displacement curves, and interaction curves. Based on the numerical results, the pure moment capacity is found to be evaluated by reducing the plastic moment capacity, and the interaction equations of N–positive Mx, N–negative Mx, and N–My are proposed in the bilinear, linear, and parabolic form. For biaxial bending, the shape of the interaction curves is almost exclusively related to the axis compression ratio. Accordingly, this paper proposes the interaction equations of Mx–My subjected to certain axial compression. Moreover, the local buckling of steel corrugated-plates has no significant influence on the shape of the interaction curves no matter the bending direction. The global stability of T-CDSCWs is not involved in the study, and with the interaction equations obtained above, the global stability design of T-CDSCWs can be investigated by introducing the magnification factor of the bending moment caused by the secondary effect.