Experimental and theoretical study on concrete-filled T-shaped steel tubular columns under uniaxial eccentric compression

Abstract

This paper presents an experimental and theoretical study on concrete-filled T-shape steel tubular (CFTST) beam-columns. Four full-scale slender beam-columns with slenderness ratio of 33.7–39.1 were tested under uniaxial eccentric compressive loads. In addition, three stub columns with the same cross-sections were axially compressed to investigate the confinement effect. Failure mode, axial displacement, lateral deflection, axial strain and hoop strain were obtained to understand the structural behavior of CFTST beam-columns. For beam-columns bended about the symmetric axis, torsion was not observed but a slight rotation of the neutral axis that was no longer parallel to the centroid axis was found by analyzing the experimental results. A fiber element model for CFTST beam-columns was developed and verified for parametrical analysis. The effects of key parameters, such as material properties, cross-section dimensions, loading angle and slenderness ratio, on the behavior of stub and slender beam-columns were investigated. Finally, theoretical models were proposed to estimate the interaction curve and the load-carrying capacity of CFTST beam-columns. The prediction matches well with the experimental results.