This article describes developments in non-destructive methods for monitoring the structure of bridges. These include use of high resolution groundpenetrating radar operating at a frequency of 2600MHz and recording to a depth of around 1m. This system can detect voids within and behind concrete, and delamination in concrete and asphalt. An acoustic monitoring systemthat is designed to detect the fracture of high tensile steel wires such as those found in post-tensioned bridges and structures is also described.The system uses surface-mounted acoustic sensors to detect the energy released by the fracture of a wire and locate the position of the break. Recent installations of this system include Bowdon View Bridge on the M56 motorway at Junction 7 and the Thorley Lane Bridge on the M56 at Junction 5.
Abstract