Experimental Study on the Degradation of Mechanical Properties of Galvanized High-Strength Steel Wires for Bridge Cables Considering Prefatigue Effect

Abstract

When the high-density polyethylene sheath of bridge cables is not cracked, the galvanized high-strength steel wires are not corroded and only subjected to the fatigue loads of vehicles (called prefatigue). Some studies have confirmed that the corrosion rate and fatigue life of certain alloy materials can be affected by the prefatigue, which is not clear for the corroded steel wires in bridge cables. In this paper, the mechanical properties of high-strength steel wires considering the prefatigue effect under fatigue-corrosion alternating loading were studied, and the residual fatigue life was predicted. First, the corrosion characteristics of high-strength steel wires with different degrees of prefatigue and corrosion were explored through an optical microscope and a surface roughness measuring instrument. Then, the static mechanical properties and fatigue life of corroded steel wires were obtained. The results show that when the prefatigue effect is greater than the corrosion effect, the surface roughness of the corroded steel wires decreases significantly, leading to a smoother surface and a weaker stress concentration. Compared with the results in the “corrosion + fatigue” case, the fatigue life of the steel wires in the “fatigue (prefatigue) + corrosion + fatigue” case may increase. The prefatigue effect has no significant effect on the static performance of the corroded steel wires. Finally, a fatigue life prediction model of corroded steel wires considering the effect of prefatigue was established based on the aforementioned experimental data.