Railway Bridge Monitoring with Sar: A Case Study

Spacebome sensors allow large areas of the Earth to be monitored with small revisit times; conversely, use of in situ techniques frequently limits spatial and/or temporal coverage of critical infrastructure observations. In this paper, some of the potentialities of synthetic aperture radar (SAR) for railway bridge monitoring are explored. The study is focused on a case study regarding a bridge near Triflisco, a small city in Campania, Italy. Twenty-six Cosmo-SkyMed stripmap SAR images were acquired over the area, allowing for a permanent-scatterer (PS) analysis of the bridge structure. Thanks to the availability of a detailed ground truth, the physical nature of the bridge PSs, their spatial distribution, and their time behavior are investigated. In particular, the PS behavior is compared to deformation results obtained using thermal loads in a finite-element model of the bridge.