Buffeting Response of Cable-Stayed Bridge during Construction under Skew Winds and Pylon Interference

Abstract

Buffeting is a kind of wind-induced vibration phenomenon of long-span cable-stayed bridges which is easy to occur. Balanced cantilever method is widely employed for the construction of cable-stayed bridge. The maximum double-cantilever state is the most dangerous state of wind resistance. Through the aeroelastic model wind tunnel experiment, the buffeting response of a cable-stayed bridge in construction under skew winds is studied in this paper. The variation law of buffeting response with the wind yaw angle is compared between the two cases with and without pylon. The experimental results show that for the same wind yaw angle the lateral and vertical buffeting responses of the main girder increase with the wind speed approximately in a quadratic curve, while the torsional buffeting response tends to increase linearly. At the same wind speed, the buffeting response of the main girder presents non-monotonic changes with increased wind yaw angle. Under skew winds, due to the disturbing effect of the pylon and the influence of the three-dimensional flow field, the buffeting response of the main girder will be affected by the aerodynamic interference of pylon. When the wind yaw angle is small, the interference effect is not obvious, with the increase of wind yaw angle and wind speed, the interference effect begins to appear. Generally speaking, the aerodynamic interference of the bridge pylon on the buffeting responses can be ignored.