Bridges
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.
