Experimental evaluation of the effect of controlled damages on the dynamic response of PC bridge beams

The present paper describes the dynamic test campaign on the prestressed concrete bridge beams taken from a dismantled viaduct in Turin, Italy after a service life of 50 years in the framework of BRIDGE|50 research project. Dynamic measurements were previously performed on the decks from which the 29 beams were taken to characterize the behaviour of the viaduct in service condition. Successively the single beams are tested to evaluate the effects of the different damage levels on the dynamic properties. The vibration data have been collected before the application of static load, after the first cracking condition and after the maximum load capacity of the beam and analysed to extract the principal modal components. The results highlight the correlation among the evolution of the damage and the dynamic response of the beam and then the effectiveness of vibration tests to identify the occurrence of damages and follow their evolution. The experimental findings will be used in future works to explore the effects of damages of the single beams on the global response of this bridge typology. This work presents the results of the experimental tests on the first three beams.