Stability design of multi-celled corrugated-plate CFST walls under combined axial and in-plane bending loads

Multi-celled corrugated-plate concrete-filled steel tubular (MC-CFST) walls are innovative steel-concrete composite walls comprising horizontally arranged corrugated steel plates, interval flat steel plates, and infilled concrete. Due to the significantly improved out-of-plane stiffness, the corrugated steel plate provides a considerable confinement effect on the infilled concrete, which enhances the structural efficiency and cost-effectiveness of MC-CFST walls. In this study, the stability performance of MC-CFST walls under combined axial and in-plane bending loads was investigated through extensive numerical simulations. A refined finite element (FE) model was established and validated using existing test results. Moreover, a formula for calculating the bending capacity of MC-CFST walls was also derived and validated against FE results. Additionally, parametric analyses were conducted to evaluate the effects of various factors such as the wall width, wall height, concrete strength, steel strength, and width of individual corrugated cells on the global stability performance. It was found that the stability performance was predominantly affected by the overall width of the wall rather than the width of the individual corrugated cells, with an increase in wall dimensions generally diminishing the stability performance. Furthermore, increasing the concrete strength improved the stability performance, while increasing the steel strength had a negative effect. Finally, a design formula was proposed for evaluating the bearing capacity and stability performance of MC-CFST walls under combined axial and in-plane bending loads. The formula demonstrated good agreement with the FE results, and it could provide a valuable reference for practical designs of MC-CFST walls.