Monitoring of Bridges

• Subheading: Satellite monitoring reveals significant differential movement

The Vienības Bridge in Daugavpils, Latvia, is an approximately 300-metre-long road bridge spanning the Daugava River and serves as a critical transportation link for the city and surrounding region. Authorities have already described the bridge as being in poor technical condition and have secured European funding for its planned reconstruction.

Sille.Space satellite-based monitoring has identified significant structural movement on the bridge. Using Sentinel-1 Synthetic Aperture Radar (SAR) data from the European Space Agency (ESA) and the Interferometric SAR (InSAR) technique, analysts detected measurable displacement affecting multiple parts of the structure.

The most notable finding is a differential displacement exceeding 35 millimetres per year in the northern section of the bridge. Differential displacement is particularly important because it indicates that various parts of the structure are moving at different rates, potentially creating additional stresses within the bridge's foundations, supports, bearings, and deck. The analysis also identified measurable displacement affecting both the northern and southern sections of the bridge, with movement patterns that appear to indicate subsidence, or downward settlement, in several locations. 

The findings are especially noteworthy because a similar satellite-analysis pattern was reportedly observed on the Carola Bridge in Dresden, Germany, prior to its collapse on 11 September 2024. The collapse of the Carola Bridge attracted international attention because a section of the structure failed unexpectedly. Fortunately, no vehicles were on the affected span at the time, and there were no fatalities, injuries, or significant collateral damage. 

It is important to emphasize that similar displacement signatures do not mean the Vienības Bridge will experience the same outcome. Every bridge has unique design characteristics, foundations, construction materials, maintenance histories, and environmental conditions. However, the comparison demonstrates how satellite-based deformation monitoring can provide valuable early warning indicators that merit closer investigation through detailed engineering assessments. 

Image source: euronews.com

While the InSAR findings alone do not indicate an immediate safety risk, they provide another layer of evidence suggesting that the bridge should remain a priority for infrastructure investment and engineering review.  As infrastructure across Europe continues to age, combining traditional engineering inspections with advanced Earth-observation technologies may become an increasingly important strategy for detecting risks before they develop into major safety concerns. 

 
https://eng.lsm.lv/article/economy/transport/25.05.2026-jekabpils-only-bridge-in-poor-condition.a648551/ 

https://www.esfondi.lv/en/about-eu-funds/news/the-government-approves-the-rules-for-allocating-european-union-funds-for-the-reconstruction-of-the-unity-bridge-in-daugavpils

https://www.euronews.com/my-europe/2024/09/12/major-bridge-partially-collapses-into-river-in-dresden

https://www.dw.com/en/germany-bridge-in-dresden-collapses-into-elbe-river/a-70185172