NASA and Bath University scientists have developed a new satellite-based early warning system that detects bridges at risk of collapse.
According to the scientists, the new satellite radar system could help governments and developers ensure that their large-scale infrastructure projects are safe and secure.
NASA’s JPL and Bath engineers verified the technique by reviewing 15 years of satellite imagery of the Morandi Bridge in Genoa, Italy – a section of which collapsed in August 2018, killing 43 people.
The bridge surprisingly showed no signs of warping in the months before the tragedy. This was until the scientists took a closer look with their new satellite radar system:
“The state of the bridge has been reported on before, but using the satellite information we can see for the first time the deformation that preceded the collapse,” notes Bath’s Dr Giorgia Giardina.
“We have proved that it is possible to use this tool, specifically the combination of different data from satellites, with a mathematical model, to detect the early signs of collapse or deformation.”
Current structural monitoring techniques are quite good at detecting signs of movement in a bridge or building; they however focus only on specific points where sensors are placed.
The radar system on the other hand can be used for near-real time monitoring of an entire structure.
“This is about developing a new technique that can assist in the characterization of the health of bridges and other infrastructure,” asserts JPL lead author Dr Pietro Milillo.
According to Milillo, the new technique marks an improvement over traditional methods.
It allows scientists to gauge changes in ground deformation across a single infrastructure with unprecedented frequency and accuracy.
The novel system makes use of the Italian Space Agency’s (ASI) COSMO-SkyMed constellation and the European Space Agency’s (ESA’s) Sentinel-1a and 1b satellites, which allows for more accurate data to be gathered.
Precise Synthetic Aperture Radar (SAR) data, when gathered from multiple satellites pointed at different angles, can be used to build a 3D picture of a building, bridge or city street.
The technique can also be used to monitor movement of structures when underground excavations, such as tunnel boring, are taking place.
Image and content: Pok Rei-Pexels/University of Bath