Dynamic Monitoring of a Railway Steel Bridge with MEMS Accelerometers: First Results on the Case Study of Portella

The continuous growth of demand on railway networks requires an efficient management strategy to guarantee proper levels of safety and service. Bridges are a fundamental asset for a railway infrastructure and their integrity must be ensured implementing feasible approaches aimed at avoiding critical occurrences (e.g. collapses) by quantifying infrastructure responses to standard and critical loads, in terms of vibration features and long-term displacements. The work proposes a geomatic monitoring configuration for a new steel railway bridge -the Portella bridge- located along the Roma-Napoli railway, showing the results obtained analyzing three weeks of continuous monitoring in different seasons. The system, based on triaxial MEMS accelerometers and envisaging additional sensors (GNSS receivers) in its developments, was installed at the end of the bridge construction as a lifetime tool, and is designed to highlight the effects of the train passage. Data analysis permitted to retrieve structure accelerations and vibration normal modes (natural frequencies). The findings of the investigations will be used to improve the Finite Element model of the bridge used in the design phase.