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Continued...
Once the inspections and sampling at each location is completed,
the cables have to be returned to their original circular profile, galvanised
wire re-wound around the circumference and the final protective coatings
applied. One of the four points where the cables pass over the vertical towers
is also being visually inspected.
The inspections are being performed by the consulting engineers to
the Forth Estuary Transport Authority, Faber Maunsell, who appointed C. Spencer
Ltd as main contractor for the project. The specialised equipment required to
compact the cable, apply the wrapping wire and provide safe working for the
high-level work was designed by Yorkshire-based consulting engineers Bennett
Associates.
The six low level inspections, which were completed earlier this
year, were carried out from scaffolding platforms on the bridge deck. For the
high-level inspections, platforms are suspended from the main cables between the
vertical hangers up to 80 metres above the bridge deck to provide weather
protection for the staff, machinery and cable interior. They measure 18 metres
long x 3.5 metres wide, weigh around 12 tonnes and are designed to be used in
wind speeds of 30mph gusting to 35mph.
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