| Using the balanced cantilever method of erection, the cable-stayed bridge during its critical construction phase resembles a long overhanging cantilever structure. This type of structure is particularly vulnerable to wind-induced buffeting instabilities because of its low natural frequencies and low overall stiffness.; In the past, the critical buffeting case for both vertical and horizontal excitation was assumed to occur when the wind was incident perpendicular to the bridge's axis. Recent observations in some cable-stayed bridges during construction revealing higher lateral responses at yaw angles other than perpendicular have triggered interest in the lateral vibration case.; Buffeting instabilities are affected mainly by the aerodynamic damping term. Experimental research for the vertical aerodynamic damping resulted in the cosine approximation. In the absence of available experimental data for lateral vibration, the cosine approximation is extended from the vertical case and assumed to be valid for the lateral aerodynamic term.; The experimental section of this thesis attempts to clarify the validity of the cosine approximation for the lateral aerodynamic damping case. Cantilever-type section models are triggered into vibration under various wind speeds and over a range of yaw angles, the aerodynamic damping is calculated, and the results are studied. |
