Wind-Induced Vibrations of the Alconetar Bridge, Spain

A vibration event which happened in the Alconetar arch bridge during construction is described and studied in this paper. Vibrations are interpreted as being caused by vortex shedding under wind and they were the result of a very light structure and a tandem cross section. Wind tunnel tests have confirmed this interpretation and they allow a satisfactory prediction of vibration amplitude by applying the correlation length model. The arch was equipped with wind deflectors which proved to be very effective to reduce vibrations. Some modifications of the correlation length model have been studied to better explain the actual behaviour of the bridge when the wind deflectors are in place.