Eccentrically loaded concrete-filled steel tubes made with high strength materials

Abstract

High-strength welded steel sections filled with high-strength concrete, so called high-strength concrete filled steel tubes (HSCFSTs), are widely used in multi-story buildings and large span bridges to achieve superior structural performance with optimized cost. Many experimental and numerical investigations have been conducted on the behaviour of small and large scale HSCSFTs under centric axial compression. However, very few studies have investigated the response of large scale HSCFSTs under eccentric loads. This paper presents an experimental investigation conducted on five square HSCFSTs that are 2.7 m height under eccentric axial compression. The effects of loading eccentricity and depth-to-thickness ratios on the behaviour of HSCFST columns were investigated. The experimental results reveal that the failure mode of HSCFSTs was governed by local buckling of the steel tube in all cases. A finite element model was also developed in ABAQUS and was validated against the test results. Sensitivity and parametric studies that investigate the effect of various parameters of the concrete damaged plasticity model, imperfections, concrete and steel strengths, load eccentricity and plate slenderness are also presented.