Remote Sensing for Stability Assessment of River Bridges: Case Study of the Red River Bridge in Winnipeg, Canada

With Canada's transportation infrastructure aging, compounded by the effects of climate change, the need to enhance condition assessment through structural health monitoring is increasingly critical to ensure integrity, performance, public safety, and cost-effectiveness. Bridge pier scouring, caused by high river flow and turbulence that erode the surrounding bed material, poses a significant threat to bridge stability and can potentially lead to failure. Conventional scouring inspections are often timeconsuming and costly. This paper presents a case study on the Red River Bridge in Winnipeg, Canada, where an innovative, multidisciplinary assessment of bridge stability was performed, including both environmental and structural investigations. The environmental investigation utilized multispectral satellite imagery and optical-band unmanned aerial vehicle (UAV) imagery, combined with large-scale particle image velocimetry (LS-PIV), to assess river flow and turbulence. An anomalous condition near a bridge pier, detected in multispectral satellite imagery, was confirmed by UAV photogrammetry and LS-PIV river current patterns. The structural investigation, detailed in this paper, incorporated Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) deformation measurements from satellite imagery, in-situ measurements on the bridge deck, and numerical bridge model predictions. This provided an assessment of the bridge's structural behavior and its potential connection to the condition observed near one of the bridge piers.