Comprehensive study of compressive behavior of CFST columns with confinements and stiffeners

This paper presents a performance study of circular-shaped short steel-concrete-filled columns (CFST) with external confinement and internal stiffening under axial loading conditions. Thirty specimens of different types of HST and CFST columns were fabricated and tested. The variables studied included concrete type, inner wall design with/without vertical strips, and shear studs. The failure pattern, deflection, axial strain, hoop strain, types of lateral confinement and their combined effects, and the effect of longitudinal strips were closely examined. The results showed that using external confinement, such as spiral or ring-type steel rods, and internal stiffening, such as vertical strips and shear studs, improved the axial load-carrying capacity and stiffness of the CFST columns. The theoretical and empirical findings of the axial load-carrying ability of CFST columns were found to be in excellent agreement with experimental results. Reliability analysis was carried out, and its results signified that the CFST column specimens with studs and stiffeners were highly reliable.