Reliability analysis of axial bearing capacity of concrete filled steel tubular stub columns with different cross sections

Abstract In this paper, Monte Carlo Simulation (MCS) and the simplified fourth-moment method based on cubic normal distribution are used to analyze the reliability of bearing capacity formula of concrete-filled steel tubular stub columns (CFST) under axial compression proposed by Ding Faxing, which considers the shape confinement coefficient of steel tube. The influence of different section shapes, different strengths of concrete and steel, two load combinations and different load ratios on the reliability index are considered. The results show: (1) the reliability index of MCS and simplified fourth-moment method are close, and the maximum difference is less than 5%; (2) the reliability of bearing capacity formulas of CFST with different cross sections meet the requirements of target reliability index 3.2; (3) When the ratio of office live load to dead load is 1.0, the lower the steel ratio and the higher the concrete strength, the greater the reliability index.