Study on the ultimate bearing capacity of 7A04-T6 CFAT columns under eccentric compression

Abstract

The application of aluminum alloys in structural engineering is growing owing to their high strength-to-weight ratio, aesthetic appearance, and excellent corrosion resistance. And extensive studies on concrete-filled aluminum alloy tubular (CFAT) columns under axial compression have been widely conducted. Still, little information was reported in the literature regarding the behavior of CFAT columns under eccentric compression. In order to investigate the ultimate bearing capacity of 7A04-T6 CFAT columns under eccentric compression, experimental and numerical studies were conducted. Test results show that the failure mode of all tested specimens was overall buckling, and specimens exhibited excellent ductility. Based on the verified finite element (FE) models, the influence of concrete strength, eccentricity, and slenderness ratio on ultimate bearing capacity was discussed and analyzed. In the absence of design specifications for CFAT columns, the design rules for concrete-filled steel tubular columns provided by European (EC4) and Chinese (GB50936-2014) standards were adopted, and steel's material properties were replaced with those of aluminum alloy. Results indicate that the predicted strength by EC4 has a good agreement with test and FE analysis results in some cases discussed in this paper. However, the design formulae in GB50936-2014 overestimate the ultimate bearing capacity of 7A04-T6 CFAT columns. Based on GB50936-2014, modified formulae that can predict the ultimate bearing capacity of 7A04-T6 CFAT columns with less than 10% discrepancies were proposed.