The role of wind tunnel modelling in the prediction of wind effects on bridges

The relationship of wind tunnel modelling to theories for flutter, vortex excitation and buffeting is discussed. The combination of wind tunnel modelling with theory based on aerodynamic derivatives and quasi-steady treatments of buffeting now allows the flutter behaviour and wind loading of even highly complex structures to be analysed. Wind tunnel models supply the essential empirical information on aerodynamic derivatives, force coefficients and admittances. It is important however to use a level of complexity appropriate to the problem and simpler traditional approaches remain valid for many bridges. The sectional model retains its long standing role as a highly sensitive tool for examining vortex shedding and flutter, including the intricate effects of edge geometry details, turbulence and damping. The full aeroelastic model gives a more complete picture of turbulence effects at high wind speeds, three-dimensional influences and construction stages. The wind tunnel is important for other issues such as component vibrations and wind forces on vehicles.