Buckling behaviour of aluminium alloy columns under fire conditions

This paper presents a systematic investigation on the buckling behaviour of aluminium alloy columns under fire conditions. One hundred and eight aluminium alloy columns, including sixty rectangular tubes and forty eight circular tubes, were tested under axial load at elevated temperature and at ambient temperature as reference. All the column specimens failed by flexural buckling. Finite element (FE) models implemented in the non-linear code ANSYS were established and verified against the experimental results. To develop a further understanding, 8829 FE models considering geometrical and material nonlinearity were conducted with four kinds of material properties, thirty four kinds of sections and five elevated temperature points. According to the FE results and statistical regression method, formulae to estimate the stability coefficients of aluminium alloy columns under fire conditions were proposed. Finally, the proposed formulae were compared with the experimental results and the stability coefficients from existing codes. It is found that the proposed formulae can provide accurate stability coefficients of aluminium alloy columns under fire conditions.