Bridge aerodynamics and aeroelastic phenomena

Abstract

This memory deals with wind-structure interaction phenomena involving atmospheric flow investing bridges and roofs. Main load models describing the different components of the wind action are introduced and described, and the conditions under which instability phenomena can occur are defined. In particular, for bridges, it is possible to express the wind load as a steady, a quasi-steady or an unsteady action. The solution of the equations of motion in the different cases allows one to identify the critical condition for galloping, torsional divergence and flutter. The effect and the representation of the turbulence action on a bridge deck are also discussed, through the introduction of indicial functions representative of an assigned admittance. Concerning roofs, the representation of the wind action via pressure coefficients is discussed and the relevant investigations in wind tunnel are presented.