High definition cameras could transform the way bridges are monitored, thanks to research by the national standards laboratory.
The National Physical Laboratory (NPL) is trialling Digital Image Correlation, which can track the movement in a structure.
The new method relies on digital technology and compares two or more high definition digital images to monitor bridge behaviour in a controlled and highly accurate environment.
The NPL hopes the technology will deliver a cheaper form of measurement than more traditional forms such as visual inspection and attaching strain gauges the bridges, which often come with associated costs such as possessions and safety equipment.
“If you have cheaper, quicker assessments then you can make them more often and the data is better,” said NPL materials scientist Nick McCormick.
Scientists from the laboratory were this week in the midst of testing the technology in the hope that it will be ready within two to three years to be used in practice.
This involves simulating how engineers will assess a bridge by using a 60 mega-pixel camera mounted on a tripod to take pictures of the bridge at measured intervals, determined by the inspection regime.
The engineer will also rely on traditional surveying techniques to ensure he/she is in the same position each time.
The two images are then fed into NPL-developed software, which tracks blocks of pixels to measure any movement within the structure. The camera and software work together to measure movements as small as 0.1mm.
Engineers can use the resultant image to calculate stain, crack propagation and deformation within the structure. To help simulate the assessment the team is using a real life, 20m long, 5m wide concrete footbridge.
This information can then help civil engineers decided if any remedial action is required to the structure.
“We just provide the tools to enable engineers to make assessments – it should be civil engineers who decide what course of action may be required,” said McCormick.
NPL is the UK’s national standards laboratory. Its Industrial Advisory Group, which helps to decide scientific research that can be used by industry, developed this new concept about three years ago.
Network Rail and the Highways Agency have already shown interest in adopting the technique.