EXPERIMENTAL STUDY ON HELICAL LINE PARAMENTS’ EFFECT ON AERODYNAMIC CHARACTERISTICS OF STAY CABLES

The vibration-related problems of stay cables, such as rain-wind induced vibration and dry cable galloping, are one of the concerns of bridge designers and researchers. In order to prevent the occurrence of rain-wind induced vibration, it is a common measure to set the helical line on the surface of the cable. In the selection of the diameter and space of the helical line, the effects of rain-wind induced vibration are usually considered, while the effects of dry cable galloping are not. In order to clarify the influence of helical line parameters, wind tunnel tests were performed to obtain vibration control effects of helical lines with different diameters and spaces, in the wind speed range of 6 m/s ~ 50 m/s with and without rainfall. The results show that the amplitude of the stay cable generally decreases after the spiral is set, but it increases first and then decreases with the increase of the helical line diameter, so the diameter of helical line should be carefully selected in engineering applications. With the increase of helical line space, the amplitude of the stay cable gradually decreases. After the helical line is set, the amplitude of dry cable galloping is significantly reduced. For the same distance, the change in the diameter of helical line has no obvious effect on the dry-cable vibration of stayed cable. For the same diameter, when the helical line space is smaller than a critical space, the change of helical line space has no obvious effect on dry cable galloping, and the cable stay vibrates obviously when the helical line space is greater than the critical space.