Reliability assessment of aluminum alloy columns subjected to axial and eccentric loadings

Abstract

The reliability and safety of aluminum alloy columns used in China is not well understood. This paper develops an improved probabilistic model for the reliability assessment of axially and eccentrically loaded columns, designed based on the aluminum alloy structure design codes of China. A comprehensive database, including 272 axially and 116 eccentrically loaded columns mainly made of 6061-T6 and 6082-T6 aluminum alloy in China, was established. Using this database, a statistical analysis of test results was conducted to determine the optimal probability distribution which can provide the best fit to the model error (ME) data and the relevant distribution parameters. The statistical parameters of ME, material strength, geometrical properties, load type, and load ratio were considered in the reliability evaluation, and a sensitivity analysis was performed to investigate the effect of these variables on the reliability indices. Then, the structural reliability levels of aluminum alloy columns in compression designed according to Chinese, American, and European codes were compared. By analyzing the optimal probability distribution of ME, the calculation results showed that the safety level of Eurocode 9 was the highest, while that of the American code was the lowest, with the Chinese code being in between. Additionally, the reliability index of 6082-T6 aluminum alloy columns was higher than that of 6061-T6. In view of the analysis results showing that the Chinese code barely met the target reliability index of 3.70, the material partial factor γR was modified for a capacity prediction model of aluminum alloy columns in compression designed according to Chinese code, to ensure that it reached the reliability requirement.