Corrosion Damage Evolution Study of the Offshore Cable-Stayed Bridge Anchorage System Based on Accelerated Corrosion Test

Abstract

The cable-stayed bridge anchorage system is prone to serious corrosion problems in the offshore environment, threatening its service safety. Based on the copper accelerated salt spray (CASS) test, the anchorage system was subjected to accelerated corrosion and then dissected along the axial direction to study the corrosion damage evolution of the internal structure. This revealed the evolution of corrosion damage in the anchorage system of offshore cable-stayed bridges. The results show that in the offshore environment, a large number of corrosion factors enter the interior of the cable anchorage system through the splicing seam at the junction of the anchor cup and the connecting barrel, and spread to both ends, thus causing corrosion damage to the anchor cup, connecting barrel, filling medium and cable steel wires. Inside the cable of the anchorage system, cross-sections with a higher corrosion level on the outer circle steel wires will also have a higher overall corrosion level. The outer circle steel wires are less able to meet the strength requirements, because they withstand most of the corrosion effects, and the corrosion pits on the surface of the steel wires will render them much weaker than the design tensile strength and fracture. After the CASS test, the ductility of cable steel wires decreases from the inner circle to the outer circle, and the higher the corrosion level of steel wires, the more obvious the brittle indications; the steel wires tend to undergo brittle failure. In the design and manufacture of the cable-stayed bridge anchorage system, special attention should be paid to the corrosion protection of the splicing seam, as well as the corrosion condition and residual strength of steel wires in the outer circle of the cable, to delay the degradation of the mechanical properties and brittle damage of the anchorage system.