Marmac Services Ltd Scope of Work includes the removal of more than 8000 metres of steel ducting and making good steelwork within the bridge structure including the removal of tack weld burrs on bulkheads at pipe cut out locations on diaphragms, NDT & re-painting painting.
The 6 no. existing 150mm dia. steel cable ducts running end to end inside the bridge shall be removed without damage to the internal cables. There are also 4 no. existing grey coloured UPVC ducts, each containing a fibre optic cable (BT Openreach) and 1No black coloured UPVC duct containing a fibre optic cable (Traffic Scotland), running the full length of the bridge. The grey UPVC ducts are intermittently routed through or attached to the exterior of the existing steel ducts which are to be removed. A black UPVC duct is also routed along the exterior of the steel ducts. Marmac are to reposition these UPVC ducts (including internal fibre optic cable) onto the new cable tray.
Where the fibre optic UPVC ducts are routed through the steel ducting, the duct route shall be identified and the fibre optic UPVC ducts shall be safely removed from the steel ducting and temporarily supported prior to final installation on new cable tray. Care shall be taken to avoid damage the existing fibre optical cables during the repositioning works. The redundant cables and ducting shall be removed from the bridge structure and taken to a licensed recycling plant. The existing service cables shall not be removed until the new services are installed and commissioned.