Multidisciplinary Investigations of a Steel–Concrete Composite Bridge

The paper presents the results from the multidisciplinary investigations performed on Baghetto Bridge. The structure, built in 1966, crosses the Adda river between the Municipalities of Castello dell'Acqua and Chiuro. It consists of three steel–concrete composite girders of different lengths supported by stone-masonry piers. The research program involved several investigations: (i) documentary research, (ii) ambient vibration testing, (iii) hydraulic study, and (iv) FE modelling and updating. After a concise review of the bridge history and a brief description of the structure, the hydraulic study based on existing topographic surveys is presented. This latter analyses allowed the estimation of hydraulic actions as well as the evaluation of possible hydro-geomorphologic scenarios. Subsequently, the complete results of the experimental tests are described and discussed. The modal parameters identified from the dynamic survey allowed validation of the numerical model, together with a more in-depth interpretation of the actual behaviour of the bridge. Moreover, the overall investigation allows to sound the presented multidisciplinary approach for the structural assessment of existing bridges.