The aim of this paper is the evaluation of the structural safety of a single-span prestressed concrete bridge, placed in a thoroughfare, a
few kilometres far from the city of Cagliari. The judgement on the reliability of the structure spreads from a diagnosis process
starting from the visual inspection and passing through in situ tests, consisting in non-destructive tests and static and dynamic testing,
whose results allowed the calibration of a finite element model, capable of representing accurately the stress-strain response of the
structure. The validation of the numerical model is based primarily on the correlation between the results of the dynamic testing, in
terms of fundamental frequency, and the numerical model modal analysis