Prediction methods for residual load-bearing capacity and service life of bridge cables

Previous research has mainly explored how corrosion affects the fatigue performance of bridge cables, with less focus on their residual load-bearing capacity throughout their service life. In this paper, a calculation method for predicting the residual strength and service life of the bridge cable was presented. After inspecting cables operational for 21 years, tensile and fatigue tests were conducted on the steel wires to assess their mechanical degradation. Based on outcomes from accelerated corrosion examinations and finite element simulations conducted under diverse stress conditions, a fitting equation of steel wire corrosion rate varying with stress was presented. Then, the corrosion state prediction model and equivalent strength calculation model of steel wire were established. Due to the discrepancy between the number of test specimens and the total number of steel wires, the overall load-bearing capacity results may be biased. To overcome this discrepancy, a method for calculating the residual strength of cables that considered the coefficient of variation was applied. Finally, the service lifetime prediction framework for cables was developed based on residual strength and rupture rate criterion. The results showed that the strength of the 1# and 2# cables was reduced by 0.5% and 5.63%, respectively. The remaining life of the 1# and 2# cables was estimated at 7.603 and 7.873 years, respectively.