Experimental Study on the Corrosion Rate of High-strength Steel Wires in Main Cables of Suspension Bridges Under Service Conditions

Abstract

To predict the corrosion progression of high-strength steel wires in the main cables of suspension bridges, this study proposes a method for calculating the corrosion rate of steel wires under service conditions. First, the corrosion rate was experimentally determined using a three-electrode system under orthogonal test conditions, varying the concentration of NaCl, pH, and tensile stress. The results reveal that both pH and NaCl concentration significantly influence the corrosion rate, with a notable coupling effect, while tensile stress has a relatively minor impact. A fitted calculation model was established to describe the relationship between these factors and the steel wire corrosion rate. Second, to validate the model, the environmental conditions of the Humen Bridge in China were analyzed. The annual corrosion rate of steel wires in this environment was estimated to be approximately 0.017 mm/year. Lastly, the diameter loss of the most severely corroded outer steel wire in the Humen Bridge's main cable was measured to be around 0.2 mm, aligning well with the model's predictions. Through experimental investigation and real-world validation, this study establishes a calculation method for predicting steel wire corrosion in suspension bridge main cables based on the internal cable environment and tensile stress. This method offers a novel approach for assessing and monitoring main cable corrosion in suspension bridges.