Dynamic Finite Element Modelling (DFEM) procedure for cultural heritage: Displacement-based reconstruction of the dynamical behaviour of the Roman bridge over the Savuto River

This study presents a metrological approach for investigating cultural heritage structures through Dynamic Finite Element Modelling (DFEM) procedure and displacement-based vibroacoustic monitoring. The Roman bridge over the Savuto River, Calabria, Italy, built in the 2nd century BC along the Via Popilia, is analysed as a case study. Broadband mechanical seismometers were deployed to measure linear and angular displacements under ambient excitation, allowing modal frequencies, thermal deformation cycles, and local dynamic anomalies to be identified. The comparison between measured responses and numerical predictions showed good agreement for the main vibration modes, while persistent low-frequency discrepancies indicated that the visible geometry alone does not fully describe the structural system. These results support the hypothesis of an additional concealed substructure beneath the riverbed, and reveal asymmetric behaviour associated with twentieth-century restoration interventions. The study shows how high-sensitivity measurements can strengthen digital modelling by transforming dynamic response into metrological evidence for structural diagnosis and heritage interpretation.