Evaluating Stress Corrosion Damage of Steel Wires as Bridge Cables Based on the Corrosion Surface

Abstract

To investigate the variation law of corrosion damage of steel wires for bridge cables, the accelerated stress-corrosion test was carried out. The corrosion surface of steel wires was collected by virtue of a three-dimensional topography instrument, and the surface characteristic parameters of steel wires were also statistically analyzed under different corrosion ages and initial strains. Finally, the maximum pit depth of steel wires was estimated by the analysis method of extreme value. The results showed that the stress corrosion intensified the corrosion degree of steel wires under the same corrosion age, and the maximum discrepancy was nearly 20%. However, the high strain level had a lower influence on the growth rate of corrosion degree in the later stage of corrosion. The pit depth of steel wires more conformed to the lognormal distribution under the unstressed condition, while the corrosion depth of steel wires more closely conformed to the normal distribution under the stress condition. The fractal dimension could not only reflect the unevenness of the corrosion surface, but also be used as one of evaluation indicators of corrosion degree. The maximum pit depth obtained from the sampling inspection data was hazardous, and it was safe and feasible to take the results from the analysis method of extreme value.