The axial compressive performance of CFSP walls under the multi-axial strength theory

Abstract

This research proposes one theoretical method to estimate both the axial compressive strength and the compressive deformation behaviour of a sandwich composite shear wall. The concrete-filled bilateral steel plate (CFSP) composite shear wall consists of one rectangular steel box in which the lateral steel plates are interconnected by binding bars and infilled concrete. The tri-axial compressive strength of infilled concrete and equivalent compressive strength of the steel plate are estimated according to the Guo-Wang failure criteria and Von Mises criteria, respectively, considering their mutual strengthening interaction. The equivalent uniaxial strain rules and Popovis equation are utilized to represent the compressive stress-strain curve of concrete and further predict the force-displacement behaviour. The local buckling displacement distribution mode of the lateral steel plate is proposed and the local buckling coefficient and the critical spacing to thickness ratio are achieved accordingly. Nonlinear static analysis of compressive behaviour of these specimens is carried out in ABAQUS. It is observed that both the FEM force-displacement curves and the theoretical curves agree well with represent the experimental curves. Considering the tri-axial compressive enhancement of concrete, a practical design formula to predict the axial compressive capacity of CFSP walls is proposed and exhibit good accuracy.