Acoustic emission monitoring techniques as applied to bridge structures, has improved significantly with the availability of more sophisticated electronic components. Regardless of their actual size, a bridge is considered a large and usually complex structure. A major difficulty occurring in bridge monitoring is what we have called "secondary source activity" which is associated with certain types of open bridge construction techniques. Bridges are also made from different materials ranging from steel, timber, concrete and brick, or mixtures of these materials. Complete instrumentation of a bridge structure can be complex, if complete monitoring is required. The basics of acoustic emission monitoring and data evaluation is very similar for each application, but there are some factors which must be both structure and application specific. The application technology developed by Metacoustics has the ability to identify the various stimulus operating on the structure; quantify the degree of damage suffered by the structure under these applied loads, and, from the basic data analysis, provide recommendations on loading regimes that will be less damaging to the structure. The Metacoustics instrumentation also has the ability to allow remote acoustic emission and taking into account local conditions monitoring.
Problems associated with old bridge structures such as this brick viaduct include the additional loading due to heavier trains, the higher curve loads, and the deformation of the ground under the foundations. Metacoustics monitored this structure with acoustic emission, micro-seismic, strain, temperature, train speed and applied load.
This steel bridge and the support piers were monitored as many trains crossed the bridge. These trains included the heaviest load in 50 years, and the Kaiser Effect was checked and verified.
By using the Metacoustics long term monitoring techniques, it was proved that the bridge structure is partially loaded prior to the train entering the bridge structure. The additional damage caused by High speed light passenger trains was also proved.