The structural behaviour of circular concrete filled steel tubular (CFST) columns with different geometries and filled with different grades of concrete, have been investigated analytically using the numerical results of three dimensional non-linear finite element model, which has been developed using commercial finite element code ANSYS. The steel tubes were having different lengths, diameters, and thicknesses, while the concrete cores were having different compressive strength. The study is focused on the parameters that include: steel tube thickness (t), outer diameter of steel tube (D), ratio of D/t and grade of concrete core. Effects of these parameters on the axial load carrying capacity and corresponding strain have been investigated. To comment on the performance, two parameter; confinement index and concrete enhancement factor are formulated, presented, and discussed.
Keywords: concrete filled steel tubular, CFST, structural engineering, ANSYS modeling, confined concrete, circular columns, CFT, tubular columns, concrete filled tubes, parametric study