Nondestructive Testing Method and Technique for Cable-Stayed Bridge Steel Cables

摘要

It is important to test the steel cables safety of the cable-stayed bridge. The wire rope tester is used in many departments, but the cable-stayed bridge steel cable testing has not been employed because many practical problems haven't been solved. In this paper, the nondestructive testing method and technique for cable-stayed bridge steel cables are proposed. Firstly, the magnetic flux leakage testing is used to test the cable damages such as broken wires, corrosions, etc. The detector contains a permanent magnet and an array of Hall sensors. It is attached to the bottom of a bridge cable and pulled along its length. As the instrument moves it magnetizes the cable. Any damages cause distortion in the magnetic field and this distortion can then be detected by the Hall arrays. The Hall sensors send the information to a computer for analysis. The difficulty of magnetization and obtaining signal is studied exhaustively. In order to pull along the tester, the cable-climbing robot is developed, too. The laboratory and field tests indicate that the tester can detect the internal broken wire in the cable and the robot can climb the arbitrary gradient cable. One of the biggest advantages of the technique is that it has little or no effect on traffic flow.