Vibration-based FE modeling and structural analysis of the Paderno iron arch bridge (1889)

The San Michele bridge (1889), one of the most important monuments of XIX century iron heritage, has been studied by Politecnico di Milano since 2009. The first part of the investigation, aimed at the assessing the state of preservation of the historic infrastructure, included preliminary dynamic tests in operational conditions as well as the design and installation (late November 2011) of a continuous dynamic monitoring system in the bridge. More recently, a FE model of the bridge was implemented, and accurate visual inspection and local survey of the corrosion state on the bridge members began, in order to obtain a dynamics-validated model including also the information on the actual local state of preservation of the main structural members of the bridge. After a brief description of the first part of the investigation, the paper describes the FE model, the correlation between the actual dynamic characteristics of the infrastructure and the model prediction, and the results of the numerical calculations carried out to evaluate the effects of present loading conditions.