Behavior of hexagonal concrete-filled steel corner columns under eccentric compression

Irregular hexagonal concrete-filled steel tubes (HCFST) are suitable for corner columns in high-rise buildings. In this paper, thirteen slender HCFST columns were tested under axial or eccentric compression. The experimental parameters included the slenderness ratio and load eccentricity. A finite element model was then developed to simulate such HCFST columns under compression. After validating the finite element model against experimental results, a comprehensive parametric analysis was carried out to generate a numerical database for HCFST corner columns to cover a wide range of parameters. Concrete strength enhancement from confinement was observed before and after the peak load. In an HCFST column, the interaction between the hexagonal tube and core concrete is mainly developed near the corners of the steel tube. A stronger interaction is found at the right-angle corners than at other corners. Equations were then proposed to predict the load-carrying capacities of HCFST corner columns under eccentric compression. Compared with the test and numerical results, the predictions from the design equations are generally on the safe side.