Inspection and Assessment of Stay Cables in Cable Stayed Bridges

That stayed cables are prone to corrosion fails to draw enough attention of bridge management until corrosion leads to damage of cables. Corrosion is usually allowed to develop for lack of accurate detection method or rather for lack of matured method of assessing tensile capacity of existing stayed cables. The tensile capacity of corroded stayed cables are affected by main factors such as cable specifications, mechanical properties of wires, extent of corrosion, and distribution of corroded wires in stayed cables. The last two factors are especially in need of systematic research. Therefore, this paper, taking advantage of the project of displacing stayed cables of Shimen Bridge, attempts an investigation of the two factors from the following perspectives: The investigation starts with measurement of corroded cable wires of the bridge to understand mechanical property of the wires and then makes an empirical fitting curve according to the mechanical change caused by corrosion. Severely corroded stayed cables are cut into several parts to expose cross sections, every wire in which is numbered for test of corrosion extent. Thus, radial distribution law of corroded cable wires is well examined. In light of the above investigation, a model is proposed to assess tensile capacity of stayed cable based on the series-parallel connection system. To verify practicality of the theory governing the investigation, one specimen made from a corroded stayed cable with the old anchor terminal on one end is tensioned and assessed using the assessing method proposed in this paper to see if the method is applicable to assessment of tensile capacity of other corroded stayed cables.