Performance of concrete-filled steel tubular stub columns reinforced with annular stiffener under axial compression: Experiment, simulation and design

This paper presents a study focusing on the structural behavior of a newly developed concrete-filled steel tubular (CFST) stub column reinforced with annular stiffener under axial compression. The annular stiffener is fabricated by curved steel plate with the circumferential plate serving as the connecting interface. The compression test was carried out on the new composite column and CFST counterparts, and the experimental findings reveal that the columns demonstrate superior capacity, stiffness and ductility than CFST columns. A validated finite element (FE) model was developed to comprehensively analyze the mechanism of composite action between components. Besides, parametric analyses were conducted to explore the influence of different parameters on the axial behavior of the members. Then, a physical and mechanical model with consideration of stiffener-contributions is proposed to predict the axial strength of stub columns. The results demonstrate that the FE modeling developed simulates well the structural behavior of the composite columns. The parametric studies suggest that the utilization of high-strength and thick wall-thickness circumferential plate is inefficient and uneconomical. Furthermore, the comparison results show the proposed design model possesses high accuracy and is in good agreement with both experimental and numerical results.