Corrosion of Bridge Cables and the Protection Methods

Cables and hangers of old suspension bridges and stays of cable-stayed bridges often suffer from corrosion problems all over the world. It may lead to breakage of wires and then to collapse of a bridge itself in the worst case. This paper tackles the cable corrosion problem from three aspects:

(1) what are tensile strength, elongation and fatigue strength of bridge wires on different corrosion levels, (2) what is the cause and mechanism to lower fatigue strength of corroded wires and (3) how to prevent corrosion progress of corroded cables. Experiments were carried out and showed: (1) tensile strength does not change but elongation and fatigue strength decrease due to corrosion, (2) the deeper and sharper corrosion pits decrease fatigue strength more, and (3) dehumidification system is the most effective protection method followed by the epoxy resin paint and filling, the zinc powder paste, and the zinc and epoxy resin paint.