Nonlinear response of concrete-filled steel tubular columns under axial loading

This study presents un evaluation of the nonlinear response of concrete-filled steel tubular (CFT) columns subjected to axial loading. A three-dimensional finite element model was developed for CFT columns. The finite element model was calibrated against existing experimental results. Analyses of columns under axial loading indicate that the stress-strain properties of the confined concrete are highly affected by the geometrical configuration of the columns as well as material properties of concrete. A comprehensive parametric study was performed to identify the effect of different parameters such as width-wall thickness ratio (aspect ratio) and concrete uniaxial compressive stress. Mathematical expressions were developed to determine thp mechanical properties of confined concrete and steel tube, that accounts for the interaction between concrete and steel tube.