Compression behaviour and bearing capacity calculation of concrete filled double skin square steel columns

Abstract

In this paper, the mechanical behavior of concrete-filled double square steel tubular(CFDSST) columns under axial compression loading was studied by experiment and finite element (FE) analysis. The diagonal angle between inner and outer square steel tubes is 45°. In the experimental work, eight columns of 300 mm outer side length were tested. The variables considered were the wall thickness of inner and outer steel tube, side length of inner steel tube and aspect ratio. The 3D FE simulation of CFDSST is carried out by using the FE program ABAQUS, which was verified by the experimental results. The validated FE model was used to build models with different variables. The experimental and numerical results show that the ultimate strength and ductility of CFDSST columns were effectively improved by using inner steel tubes. Finally, the ultimate strength calculation method was proposed, which provides accurate prediction compared with experimental results and FE results.