The action of flexible bridges under wind, II: Buffeting theory

By using the analytical and conceptual format set forth in the first of these two companion papers, the problem of bridge buffeting under natural wind is considered. Again, bridges having vibration modes that are not necessarily simple are dealth with. The buffeting action of random wind forces in the presence of self-excited, or bridge motion-induced, forces is discussed, as are energy considerations associated with bridge stability. A possible explanation is offered for the well-known fact that turbulence in the incident wind often delays the onset of flutter.