Corrosion Behavior And Service Life Evaluation Study On Cable Of Cable-Stayed Bridge

The majority of domestic cable-stayed bridge built in the 1970s and 1980s replacement the cables because of corrosion. This paper is mainly based on studying the cable-stayed bridge on corrosion behavior of cable, through precise finite element analysis and indoor-accelerated corrosion test establish the mathematical prediction model indirectly dynamic to master security status cables of cable-stayed bridge,providing a reasonable time for cables replacement and service life evaluation.First of all, through field investigation and the collection of domestic cables of cable-stayed bridge protection and corrosion, failure characteristics of the cable-stayed bridge cable protection and corrosive morphology of cable wire is analyzed and the major environmental factors of rate of cable corrosion is discussed. Secondly, the stress corrosion theory, corrosion fatigue theory and the theory of fracture mechanics is applied to post the promote mutual relations among cable wire's stress, corrosion, fatigue and the influence in the life of cables. Thirdly, form the cable wire's overall corrosion and corrosion on the local section of the wire, effect of the reduction of the wire's section area and local stress of cable steel wire is analyzed .Last of all, corrosion degree evaluation method of cable steel wire overall corrosion and local corrosion is established. Method based on the depth of overall corrosion and the greatest depth of pitting can apply to predict the life span cable-stayed bridge cables. This paper gets the polynomial formula about different etch-pit morphology and largest local stress, form establishing precise finite element model of corrosion wire, and studying the effect of local stress'distribution of corrosion wire with different etch-pit morphology and yield load of corrosion wire. Formula established can be used to determine the largest local stress of corrosion wire and cable life prediction. Through indoor-accelerated corrosion test, the formula about cable-stayed bridge zinc plate of steel wires and steel corrosion rate which is changing by stress is established, the relation between the depth of steel etch-pit morphology and overall corrosion of the steel cable, and the distribution rule of cable sections'corrosion are discussed. The quantitative forecasting model of cable service life is established based on failure criterion about the largest equivalent stress.This paper forms ideas of study of the corrosion by combining corrosion behavior, precise finite element analysis, indoor-accelerated corrosion test study and other studies designedly. It also provides a practical assessment analytical method of the life prediction of structural corrosion and structural bearing capacity.