ABSTRACT
ABSTRACT Stay cables of cable-stayed bridges and exstradosed bridges are very difficult to inspect by visual inspection, because there are in high places. The high-strength steel wire or strand used for stay cables may be broken due to corrosion due to penetration of deterioration factors, or fatigue due to stress fluctuation. Therefore, efficient non-destructive inspection devices are required for inspection of the degradation of the steel wire or strand in the protective tube. In order to solve these problems, the automatic stay cable inspection device was developed and operated on the prestressed concrete cable-stayed bridge. This inspection device can visually inspect the protective tube with cameras and can detect non-destructively the breakage of the steel wire or strand in the protective tube with the eddy current flaw detector. This inspection device is possible to automatically raise, lower and stop on the stay cable by wireless operation, it can inspect the stay cable with a diameter of 100 to 200 mm, a maximum length of 200 m, and a maximum oblique angle of 65 degrees. And, it can be visual inspection and recording for the protective tube of stay cable with the video cameras, it can inspect by the eddy current test whether or not the steel wire or strand of the stay cable breakage. This paper describes the outline and effects of this inspection device.
