DFOS solutions covering full monitoring needs of an enlarged concrete deck viaduct

Le résumé fourni par la source

The 1960s economic boom led to spread construction of large transport infrastructures. Many of these steel reinforced concrete structures attain their end of lifespans on this and next decade. With no major renewing plan, repairing and retrofitting are explored alternatives. A good example is Milano's ring-road viaduct; while already repaired and its concrete deck enlarged, SHM begins nowadays. Monitoring of thermal and mechanical induced strain, static and dynamic, brings access to permanent strain, thermal expansion, eigenmodes of each single road span and better understanding of the whole structure dynamic behaviour. Three trucks moving at 30 km/h load dynamically the enlarged deck, while real traffic is used for modal analysis. Often, this kind of comprehensive monitoring requires combining various measurement technologies, making their installation time consuming and expensive. Thus, the number of sensors may be undercut, and measurement campaigns duration reduced, which may result in poorer monitoring results and mismatching between experimental results and model's ones. FEBUS SHM solutions based on DAS (Distributed Acoustic Sensing), DSS (Distributed Strain Sensing) and DTS (Distributed Temperature Sensing) provide quick instrumentation and easy monitoring. With long-range devices to address tens of km of infrastructure instrumented in a row, up to 400 kHz continuous monitoring, state of-the-art DAS repeatability threshold of 2 picoStrain/SquareRoot(Freq), FEBUS DFOS (Distributed Fiber Optics Sensing) brings valuable results for every node of the structure.

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