Experimental Research on the Apparent Corrosion Law of a Suspension Bridge’s Main Cable Steel Wire under Status of Holding Force

Abstract

Regarding the corrosion law of a suspension bridge’s main cable steel wire under the status of holding force, a set of electrolytic-accelerated corrosion test devices with preload was designed. The electrolytic-accelerated corrosion test of the main cable steel wire of a suspension bridge under the status of holding force was carried out. A total of 60 steel wires with diameter 5.25 mm were selected under four working conditions of 0, 1,000, 2,000, and 3,000 μϵ. The quality and diameter of steel wire after 0–4 days of electrolytic-accelerated corrosion were measured. Additionally, the change law of the average mass loss rate and cross-sectional loss rate of the main cable steel wire with strain and time growth were discussed. The results of the tests showed that with the increase of strain level and corrosion time, the corrosion of steel wire under the stress state is more obvious, the fluctuation of local characterization is more intense, and the corrosion presents a nonlinear growth trend. The mass loss of the steel wire with 3,000 μϵ after four days of accelerated electrolytic corrosion is similar to the 420-day test result of natural corrosion, and the change trend is consistent. Under accelerated corrosion conditions, the average mass loss rate of a steel wire with 3,000 μϵ after four days of accelerated electrolytic corrosion is 6.40 times that of one day. At the same time, the average mass loss rate of steel wire with 3,000 μϵ after one to four days of accelerated electrolytic corrosion are 1.17 times, 1.22 times, 2.27 times, and 3.02 times than 2,000 μϵ respectively. The maximum section loss rate increases with the increase of strain and time, and it has a good correlation with the two variables. Therefore, the maximum section loss rate can be considered as the core intermediate variable to measure the corrosion grade of main cable steel wire.