We were commissioned by J. Gallagher on behalf of Scottish Water to carry out a tunnel inspection of a 4.3m diameter raw sewage dual storage/transfer tunnel that ran for 5.2km under the City of Glasgow. There were no-intermediary access shafts which necessitated the design and manufacture of a bespoke low friction, high workload 6km fibre optic cable.
Our remit was to visually inspect above water with CCTV and measure the profile of the tunnel and silt levels below water with profiling sonar. The estimated average water depth was around 1m and the estimated flow rate was 1m/second. The inspection had to be synchronised with suitable weather conditions to ensure an optimal water depth and flow rate; excessive rain would create torrential flows and the tunnel would surcharge.
We designed and fabricated stainless-steel roller assembly brackets for the upstream and downstream shafts, which were installed by Gallagher’s and left in place upon completion of the inspection for future works.
We built a wide angle, high-definition zoom camera and pan & tilt head which was installed on the floating Pipe Inspection Vehicle (PIV) to ensure that we could obtain close-up images of any deformation or damage.