RESIDUAL LIFE PREDICTION AND DESIGN CORRECTION METHOD OF CORRODED CIRCULAR STEEL TUBES BASED ON TIME-VARYING RELIABILITY

Current research on the effects of corrosion on the safety of steel members is primarily focused on the degradation of the ultimate bearing capacity, and there is a lack of research on the reliability-based service life assessment. In this paper, a modified reliability function and an uncertainty model for each parameter considering the effects of corrosion are established based on the reliability analysis method of the GB50068-2018 design specification. The effects of the corrosive environment category, wall thickness, and slenderness ratio on the time-varying reliability of axially compressed round tubes are analyzed. The results indicate that an increase in the corrosion duration and the environmental category can cause a decrease in the reliability index of the component, and the smaller the wall thickness, the faster the corrosion-related degradation of the reliability index. However, with the increase of the slenderness ratio, the corrosion-related degradation of the reliability index gradually decreases. In the end, a residual life prediction method and a design correction method for corroded components based on the reliability index are p roposed. Moreover, the values of the corrosion life and corrosion coefficient of circular steel tubes for different environmental categories, slenderness ratios, and thicknesses are determined. This paper provides a technical reference for the residual life prediction and full life design of round steel tubes considering local corrosion.