Structural health monitoring design for the A3 bridges in Naples

The paper shows the design approach of structural health monitoring (SHM) systems for a group of viaducts realized in '70 that connect in the port of Naples with the A3 Italian highway. Given the frequent traffic of heavy vehicles and deterioration phenomena of the existing structures, a reliable monitoring system can be an important support to enhance safety over time allowing timely maintenance intervention. The bridges constituting the infrastructure are mostly simply supported structural systems with several half joint (Gerber) bearings. However, the structural schemes are characterized by different geometric layouts, especially for main beams and piers. Superstructure decks are made of post-tensioned PC beams or composite steel-concrete beams/caissons. An integrated monitoring system was designed considering dynamic and static measures. Multiaxial accelerometers were located to measure acceleration during the transit vehicle and to identify main dynamic properties of the superstructures, as well as interactions with the substructures. Furthermore clinometers, displacement transducers, humidity and temperature sensors were added to collect deformability parameters under the traffic loads. Accelerations recorded at different times of the day on one viaduct are briefly shown, pending the collection of more data that will allow a check on the consistency of the measurements recorded by the various instruments. The FEM of the structure that will be used as support in interpreting the measurements is briefly introduced.