Drag loading of circular cylinders inclined in the along-wind direction

The drag wind loading on the stay cables of long cable-stayed bridges is discussed based on two recent long-span cable-stayed bridge designs. For wind along the bridge, the available design literature on cable drag coefficients either do not cover the actual cable configurations or are too conservative. Therefore, some simple design values had to be devised. These design values for the cable drag coefficient are then compared with measured drag coefficients for various types of cable surface treatments introduced to suppress rain-wind vibrations. A modified expression depending on cable diameter and inclination is also proposed and the applicability of the expression is discussed.