Integrated health monitoring of masonry arch bridges by Remote Sensing and Ground Penetrating Radar technologies

Advances in data processing and the availability of larger SAR datasets from high-resolution (X-Band) satellite missions have consolidated the use of the Multi-Temporal Interferometric Synthetic Aperture Radar (MT-InSAR) technique in the near-real-time assessment of bridges and the health monitoring of transport infrastructures. This research aims to investigate the viability of a novel non-destructive health-monitoring approach based on satellite remote sensing and ground based techniques for structural assessment of bridges and the prevention of damages related to structural subsidence. To this purpose, high-resolution X-Band SAR products were acquired and processed by MT-InSAR technique. Analyses were developed to identify and monitor the structural displacements of the historical "Ponte Sisto" masonry bridge located in Rome, Italy, crossing the Tiber River. To this extent, the historical time-series of deformations were processed by Persistent Scatterers (PSs) relevant to critical structural elements of the bridge (i.e., bridge piers and arcs). On the other hand, an on-site Ground Penetrating Radar investigation was directly conducted over the masonry bridge. More specifically, several frequencies were implemented for this purpose, with the aim to investigate the condition of the layers of the superstructures at different propagation lengths. A novel data interpretation approach is proposed based on the selection of several PS data-points with coherent deformation trends and location on the bridge, and the analysis of the B-Scan obtained by GPR investigations. The outcomes of this study demonstrate how multi-temporal InSAR remote sensing techniques can be applied to complement non-destructive ground-based analyses (e.g., ground-penetrating radars), paving the way for future integrated approaches for monitoring of infrastructure assets