Dynamic testing for structural identification of a bridge

Structural identification via modal analysis in structural mechanics is gaining popularity in recent years, despite conceptual difficulties connected with its use. This paper is devoted to illustrate advantages and also indeterminacy characterizing structural identification problems for bridge structures, even in rather simple instances. In particular, an identification procedure based on modal analysis and finite element model updating is presented for the characterization of a concrete bridge which constructive typology is quite diffuse in the area of Friuli Venezia Giulia (Italy). Experience has suggested, so as to restrict the indeterminacy frequently affecting identification issues, having resort to all the a priori information on the system and mindfully selecting the parameters to be identified. The analysis pointed out some particularities of the modelling of the bridge typology under study, otherwise not a priori detectable from the analytical point of view.