Eccentric compressive behavior of circular concrete-filled aluminum alloy tubular columns

Concrete-filled aluminum alloy tube (CFAT) is an innovative composite member that offers excellent ductility, high bearing capacity, strong corrosion resistance, and lightweight characteristics. However, research on the eccentric compression performance of CFAT columns is still limited. This study focuses on testing nine circular CFAT columns under eccentric compression. The test parameters included slenderness ratio (12, 32, and 56) and eccentricity-to-radius ratio (0.33, 0.67, and 1), both of which led to a reduction in ultimate strength as their values increased. All specimens exhibited overall bending as failure mode. A finite element model was developed to predict the ultimate strength of composite columns, demonstrating good agreement with the test results. The parametric analysis was conducted to evaluate the influence of aluminum alloy grade, concrete strength, tube thickness, and slenderness ratio on the axial load-bending moment responses. The existing design codes of concrete-filled steel tubes (CFSTs) were applied to calculate the ultimate strength of circular CFAT columns. Among them, CECS provided reasonably accurate predictions, while EC4 showed the best agreement with the test results.