Bridge’s Displacement Monitoring Using Persistent Scatterer SAR Interferometry

Kurzfassung

Over the last two decades, satellite Synthetic Aperture Radar (SAR) interferometry has become a powerful tool to monitor the motion of urban areas. Exploiting PersistentScatterers (PS) over long-time span allowed the analysis of how linear deformation and thermal displacement affect the displacement infrastructures. This is of particular interestfor bridges which suffer continuously of periodic and non-periodic oscillations; temperature, active traffic and surface’s roughness are only some of the main vibrating sources. The first one, that interacts with all the objects on the ground, represents an important contribution to the displacement of structures, especially to the ones made of steeland concrete. This kind of infrastructures are known to be suffering by environmental effects which interact with bridge’s movements. Succeeding in isolating the longterm deformation signal from the shot-term oscillation one, would allow to monitor the overallstructural trend; indicating an abnormal deformation and the need for a more detailed ground investigation. In this work, the oscillations of bridges are studied with particular emphasis on the thermal component. Cologne bridges are cases of analysis to demonstrate the potential of Persistent Scatterer Interferometry (PSI) for monitoring the movementsof these structures due to the thermal expansion and understand if other displacement sources might have a non-negligible role.