Site: Battersea, London
Contractor: Clancy Docwra / Joseph Gallagher
Client: UK Power Networks
Products Supplied: Precast concrete Tunnel and Shaft segmental lining systems and Precast concrete cover slab
The Vauxhall, Nine Elms, Battersea (VNEB) designated development opportunity area is by far the largest regeneration zone and one of the last remaining industrial stretches in central London.
The area spans 227 hectares along the south bank of the Thames between Vauxhall and Chelsea Bridges. The plans include 16,000 new homes, an extension to the Northern Line and regeneration of the Battersea Power Station site.
To provide the electricity infrastructure to this development and the Northern Line extension, UK Power Networks is building a new substation in Battersea within the VNEB area to deliver an increase in capacity of 86 Mega Volt Amp (MVA).
The project involves both the construction of a new substation and a 300 metre spur tunnel to route the power cables to the new substation site. Working on behalf of the main contractor Clancy Dowcra, tunnelling specialist Joseph Gallagher has recently completed construction of the 2.44m diameter cable tunnel, which has been lined with FP McCann’s 2.44m id trapezoidal smoothbore precast tunnel segments, manufactured at the company’s Cadeby facility in Warwickshire.
In order to lower the tunnel boring machine to the required depth, a 25 metre shaft was sunk in an existing building in the Battersea area. The building was modified to provide sound insulation, allowing the shaft and tunnelling works to be undertaken with minimum impact to the surrounding area. The 7.5 metre diameter back-bolted access shaft has also been supplied by FP McCann and installed by Joseph Gallagher using the top down caisson method of build. Each precast 7.5m shaft ring was jacked down from the surface using powerful hydraulic rams.
FP McCann also supplied a 7.5 metre precast concrete cover slab to cap off the shaft.
Commenting on the contract, Paul Challinor, Project Manager for Joseph Gallagher says, “Using the FP McCann precast concrete tunnel and shaft segmental lining system is an extremely efficient way to deliver the cable tunnel to the client’s specification and project timings. With storage space restrictions on site, we have worked closely with the FP McCann logistics team to ensure just-in-time deliveries to the job”.
The regeneration site will be completed in a phased manner to reflect requirements of large developments in the VNEB area and is scheduled for completion by December 2019.