Vortex induced vibrations of a bridge deck: Dynamic response and surface pressure distribution

This paper describes selected results collected during the wind tunnel tests carried out at Politecnico di Milano Wind Tunnel on the deck sectional model of the Messina Strait Bridge. It is a long span suspension bridge characterized by a multi box deck. Aerodynamic forces and surface pressure distributions have been measured in order to characterize static and dynamic response of the deck. Vortex induced vibrations phenomenon has been studied with particular attention: it represents one of the most important aspects to be considered while designing the deck shape of long span bridges and it has to be carefully analyzed. In fact, even if it can be separated from the stability problem for the modern bridges, VIV, in case of low Scruton numbers, can lead the deck to reach very large vibration amplitudes, also at very low wind speeds.