Study on Buckling of Concrete-filled double skin steel tubular columns

The concrete-filled double skin steel tubular columns (CFDST) are regarded as one of the composite columns consisting of double steel tubes with square or circular hollow sections and the space between two skins is filled with concrete. These columns possess several advantages, including a proper performance during loading, smaller dimensions, cost-effectiveness, protection of the concrete surface against the damage, others compared to conventional columns. In this paper, the buckling of the concrete-filled double skin steel tubular columns subjected to the axial compression was assessed using finite element software, ANSYS. For further investigation of the various types of this novel column system, the nonlinear behaviors of the 3D model of the double skin sections with various cross-section shapes of the section were compared and the influence of the support condition was studied Moreover the buckling of the columns filled with self-compacting concrete, which is required due to the difficulty in the pouring in the confined space, was scrutinized. The results for the short CFDST columns indicate that the column with square-outer-section and circular-inner-section tubes exhibited high buckling critical load and better ductility. Variations in the support conditions do not have significant influence on the columns.