Performance of T-shaped CFST stub columns with binding bars under axial compression

This paper investigates the axial compressive behaviour of T-shaped concrete-filled steel tube (CFST) stub columns with blinding bars. In this column system, binding bars are applied cross-through the section and produce confinement effects. Eleven specimens with binding bars and five ones without binding bars were tested under axial compressive loading. The experimental results demonstrate that, by setting binding bars, the local buckling failure modes are changed and the occurrence of local buckling is delayed, and the global outward bulge of the steel tube at the concave corners can be effectively restrained. The ultimate strength and ductility of the columns with binding bars can achieve up to 1.53 and 7.5 times higher than those of the columns without binding bars, respectively. Taking into consideration the contribution of binding bars, the confinement effects of steel tube and the other sectional characteristics, a method for predicting the ultimate axial compressive strength of the columns with or without blinding bars is established. The accuracy of the method is validated through comparisons of the experimental results reported in this paper and in other available open literatures.