Modal Characterization of a Prestressed Reinforced Concrete Bridge Composed by Decks with Different Ages

The use of ambient vibration test for modal characterization of structures is becoming a common practice to capture samples of the experimental response of the “real structure”, especially for existing structures where conditions with respect to the “as-built” state can be further different due to the presence of deterioration phenomena. The present work illustrates experimental activities and data process of dynamic tests carried out on a prestressed reinforced concrete bridge, located along a highway in Italy. The structure is characterized by four main decks built in two different ages. Objective of the tests was to determine modal parameters of the two bridges, like vibration frequencies, mode shapes and damping-ratios, to calibrate a FE model. Furthermore, the longitudinal and transversal joints behavior was investigated.