Axisymmetric Modelling of Circular Concrete-Filled Double-Skin Steel Tubular Short Columns Under Axial Compression

Recently, concrete-filled double skin steel tubular (CFDST) columns have been extensively developed and used for many structures. CFDST columns consist of inner and outer steel tubes with the concrete filled in the space between them. Compared to conventional CFST columns which have only a single steel tube with concrete core, the CFDST column offers some advantages such as lighter weight, better cyclic performance, and higher fire resistance period, etc. This paper proposes an effective axisymmetric model for performing the nonlinear inelastic analysis of CFDST columns subjected to uniaxial compression in ABAQUS software. An efficient constitutive material model of the concrete infill was employed to consider the confinement effects which increase the ultimate stress, strain, and ductility of the column. The accuracy of the proposed model was verified by comparing its prediction with experimental results and predictive results obtained by the three-dimensional (3D) model of the CFDST column. It was demonstrated that the predictive results obtained from the proposed model agree well with those of the experimental data. In addition, it was pointed out that the proposed axisymmetric model of CFDST column can significantly reduce the computational time (about 30 times) compared with the corresponding 3D model.