Spatiotemporal characteristic analysis of cross-river bridge deformation in Jiangsu Province with InSAR

Interferometric synthetic aperture radar (InSAR) was applied to Sentinel-1 satellite imagery from 2015 to 2024 to monitor long-term deformation of various cross-river bridge types in Jiangsu Province, China. The results demonstrate that InSAR effectively captures cross-river bridge deformation, with monitoring efficacy influenced by geometric structures and material properties of the bridge. Continuous steel truss structures and steel bridge towers exhibit strong backscattering characteristics, enabling dense monitoring point distributions that finely depict periodic deformation characteristics. For cable-stayed and suspension bridges, deformation concentrates at the mid-span and attenuates toward both ends, with notable differences in cumulative deformation magnitude. Integrated temperature data analysis reveals pronounced thermal expansion and temperature shrinkage effects in continuous steel truss bridges, characterized by periodic deformation amplitudes increasing from the mid-span center to both ends. Thermal effects in cable-stayed and suspension bridges are predominantly localized at steel bridge towers.