方形铝合金管混凝土短柱长期性能研究

Concrete-filled aluminum alloy tube (CFAT) not only has similar structural performance comparable to traditional concrete-filled steel tube (CFST), but also possesses excellent corrosion resistance and good appearance, which makes CFAT a promising option for exposed structures operating in highly corrosive and high-salt environments. Considering the significant impact of concrete creep on the structural responses of composite structures, this paper focused on the long-term behavior of square CFATs. A finite element model was developed using the temperature reduction method, which accounted for the time-dependent development of passive confinement and the Poisson effect of concrete creep by defining an anisotropic thermal expansion coefficient. Through parametric analysis comparing the long-term performance of CFAT with CFST, it is found that the square CFATs exhibit a significantly larger increase in long-term deformation, ranging from 28. 6% to 131. 6% . Key parameters of influencing the long-term deformation include the aluminum ratio, concrete strength, loading age and loading duration. The nonlinearity of creep in square CFATs is not pronounced, with the difference in long-term deformation increase being 21. 5% to 44. 7% when the stress ratio is from 0. 5 to 0. 75, which is 78. 9% -93. 4% lower than the results in CFSTs. Additionally, the stress levels in aluminum alloys during the service life are relatively low, and they typically do not yield due to time-dependent effects.