On the Use of Satellite-Based Interferometry for Structural Monitoring of Bridge Portfolios

Transport network management authorities need to address targeted monitoring and structural assessment on appropriately selected critical bridges to improve the serviceability and safety of the network optimising the involved financial budgets and resources. The multi-temporal satellite-based differential interferometry, commonly referred to as MTInSAR, is a remote-sensing technique aimed at detecting displacements of coherent scatterers on the terrestrial surface with centimetre- to millimetre-level accuracy. This paper applies an MTInSAR-based methodology for the portfolio-scale evaluation of deformation phenomena on bridges, suitable for addressing targeted sensor-based monitoring or on-site inspection plans. The methodology is applied to a case-study highway network in Roma (Italy) by using Sentinel-1 (C-band) and COSMO-SkyMed (X-band) satellite datasets. The interferometry products are processed to identify bridge-specific deformation scenarios. The MTInSAR products and the deformation scenarios related to some specific test bridges subjected to subsidence phenomena are analysed to highlight the advantages and disadvantages of the investigated approach.