A consortium led by the University of Nottingham joined forces with the operator of the Forth Road Bridge in Scotland to develop a system, called GNSS & Earth Observation for Structural Health Monitoring (GeoSHM), which uses space assets for monitoring purposes. The activity was supported by ESA under its ARTES programme, which funds and promotes the development of space-based applications and services.
The consortium deployed four highly sensitive GNSS receivers and two anemometers to measure short-term movement, as well as Earth Observation (EO) data from the Copernicus satellite to measure long-term ground movement.
“Based on our experiences with the Forth Road Bridge, we’ve discovered that EO is a powerful tool to monitor both local changes to the surrounding ground as well displacements of key components of such structures,” said GeoSHM team leader Xiaolin Meng from the University of Nottingham. Analysing historical EO data, the consortium detected no apparent displacements of the towers or the surrounding soil during the previous seven years.
Forth Road Bridge bridgemaster Barry Colford has found the GeoSHM information to be extremely useful for understanding how much the bridge can move under extreme weather conditions. “This allows us to decide to close the bridge based on precise deformation information. For example, I knew that the bridge can move significantly under high wind loading but for the first time I know that bridge moved 3.5 metres laterally and 1.83 metres vertically under wind speed of 41m/s. Other information provided by the GeoSHM system is also important to define reliable alarm thresholds for issuing the right alerts at the right time."
The solution installed on the Forth Road Bridge is a small-scale proof of concept to demonstrate the technical feasibility. The consortium is now planning a follow-up project, in which Forth Road Bridge as well as several major bridges in China may be used to further develop the technology. The University of Nottingham, China Rail, and China Railway Major Bridge Reconnaissance & Design Institute (BRDI) are also examining the possibility of setting up a commercial company in the UK to promote GeoSHM in China, where nearly half of the world’s long span bridges are situated.
"We see tremendous potential for deploying space assets in a cost-effective way for this vital activity," said Beatrice Barresi, a telecom engineer overseeing the project for ESA. "The combination of long-term monitoring of ground levels using Earth Observation data and short-term GNSS positioning creates a potent information service."
