Multi-Temporal SAR Interferometry for Structural Assessment of Bridges: The Rochester Bridge Case Study

Multi-temporal Interferometric Synthetic Aperture Radar (InSAR) is a space-borne monitoring technique able to detect cumulative surface displacements with a millimetre accuracy within the line of sight (LOS) of the radar sensor. Several developments in the processing methods and an increase in the availability of SAR data sets from different satellite missions have proven the viability of this technique in the near-real-time assessment of bridges and the health monitoring of transport infrastructure. This research aims to demonstrate the potential of satellite-based remote sensing techniques in developing an innovative health-monitoring method for structural assessment of bridges and the prevention of subsidence damage, using high-resolution SAR data sets and complementary ground-based (GB) non-destructive testing (NDT) techniques. To this purpose, high-resolution COSMO-SkyMed (CSK) products provided by the Italian Space Agency (ASI) were acquired and processed. A multitemporal InSAR analysis was developed to identify and monitor the structural displacements of the Rochester Bridge, located in Rochester, Kent, U.K. This bridge is composed by four separate bridge decks carrying the A2 Road, a railway, and a service-bridge carrying service pipes and cable. The outcomes of this study demonstrate how multitemporal InSAR remote sensing techniques can be synergistically applied to complement the traditional GB analyses (e.g., ground penetrating radar, laser scanner, and accelerometers) and information on river bridges (e.g., river levels from monitoring stations). This can provide an extended spatial coverage and an effective identification and monitoring of defects and decays at reduced costs, compared to traditional monitoring techniques. © ASCE.All right reserved.