Study On Influence Of Cable Corrosion Damage On Cable-stayed Bridge Structure

After decades of rapid development,cable-stayed bridge has become one of the main types of modern long-span bridges.Cable-stayed cable is the lifeline of the whole structure system and is one of the most important load bearing components.However,during the service process of the cable-stayed bridge,cable stays is in a harsh natural environment for a long time and it is easy to cause corrosion damage,seriously affect the durability of the cable-stayed bridge,and threaten the safety of the bridge.(1)This paper was based on the latest research on the identification and evaluation of the corrosion damage of the cable at home and abroad,the corrosion damage cases of cables in some cable-stayed bridges are statistically analyzed;summarized the disease type of cable corrosion.The reason and mechanism of each disease were analyzed in detail,especially the cause and mechanism of the corrosion caused by the wire corrosion of cable.(2)Using a multi-functional salt spray corrosion box to perform copper accelerating acetate spray test on high-strength steel wire and sections of cable,studying corrosion status of galvanized steel wires,establishing a classification standard for the degree of corrosion of steel wires,and analyzed the corrosion morphology of steel wire under static and stress-free conditions and its effect on corrosion rate.The tensile test of corroded steel wire specimens was carried out to obtain the mechanical properties data of corroded steel wire specimens.The test also compared and analyzed the difference in mechanical properties between lossless steel wires and corroded steel wire under both static and stressless accelerated corrosion conditions.The ultimate load,yield load,elongation after breaking,and loss rate of strength were studied along with changes in mechanical properties such as corrosion rate.(3)The copper accelerating acetate spray corrosion test was carried out by breaking the PE sheath of the cable segment in different damage forms(holes,strips,rings)to study the corrosion state of the cables after removing the protective layer and the corrosion distribution law of the cluster steel wire along the length direction of the cables and the cross section direction of the cables.According to the classification criteria of the degree of corrosion of steel wire and the corrosion distribution rule of the parallel bundled steel wire in the cable,the classification criteria for the corrosion degree of the cable was set up and classify the corrosion grade of the cable into 5 levels,proposed corrosion damage assessment method for cable.(4)Based on a cable-stayed Bridge,the finite element model of the cable-stayed bridge was established to analyze the static influence of corrosion damage on the bridge structure.The effects of different position cables on the main beam line shape,main tower offset,and cable tension under the same degree of damage were analyzed specifically;the effects of same position cables on the main beam line shape and cable tension under the different degree of damage were analyzed.