Sectional strength and design of double-skin composite walls withre-entrant profiled faceplates

Profiled steel sheets are widely used in composite wall systems to form profiled double-skin composite walls (PDSCWs), serving as structural components in lowand medium-rise building structures. By using the profiled faceplates with re-entrant corrugations, the trough regions not only form vertical ribs to enhance the stability performance of the faceplates, but can also hook to the infilled concrete to eliminate the need for additional connecting elements. The sectional strength of the PDSCWs under combined axial and out-of-plane bending loads is investigated in this paper. A nonlinear finite element (FE) model is presented for simulating the combined axial and bending resistant behaviour, which is validated by comparing with independent series of tests. A numerical parametric study is conducted, which involves the parameters including faceplate thickness, wall depth, face-plate steel strength, infilled concrete strength and faceplate type, and the interaction curves between ultimate axial and bending resistance (N -M curves) are obtained based on extensive models with different eccentricities. By introducing a sectional analysis model which considers the local buckling effect of faceplates, the sectional axial and bending strength of PDSCWs is theoretically evaluated. By comparing the derived N-M interaction curve against FE results, it is found that the proposed design formulas are capable of conservatively predicting the ultimate resistance of the PDSCWs under combined axial and bending effects. Hence, these formulas can provide valuable references for designing the PDSCWs in practise.