Spatial corrosion characteristics and their evolution process of corroded wires in stayed cables

Abstract

The corrosion evolution of steel wires inside a cable is crucial for its service performance evaluation and prediction. However, it is still a challenge to construct an effective model to evaluate the corrosion status of steel wires inside a cable, owing to the complicacy of this corrosion evolution. Therefore, this study conducted an accelerated corrosion test of stayed cables with initial sheath breakages and established a probability prediction model for wire’s corrosion evolution based on Bayes theory. The proposed Bayesian prediction model involved two critical parameters, i.e., the shortest effective path and corrosion duration. Besides, the spatial distribution characteristics of steel wires inside a cable were explored. Analysis results show that the corrosion evolution of steel wires inside a cable is intimately associated with their spatial positioning and the corrosion duration. A power function can approximate the correlation between the wire’s corrosion degree and corrosion duration, as well as wire’s space location. The corrosion degree and corrosion rate of the wires near sheath breakage are significantly higher than the others. The size of sheath breakage affects corrosive medium’s path to the target wire but has little effect for outer steel wires. In the early stage, corrosion evolution of wires near breakage is more significantly affected by corrosion duration. While wire’s corrosion rate tends to be stable in the late corrosion stage. The corrosive medium prefers to diffuse along longitudinal direction of a cable rather than along the radial direction. According to the validation, the calculations of the corrosion evolution model of steel wire are reliable.

Keywords

• Cable stayed bridges
• Shortest effective path
• Corrosion evolution
• Spatial characteristics of corrosion