Case Study

London Power Tunnels

Client

Costain / Skanska JV

Dates

2015

Location

Wandsworth - London

Value

£210k

The Project
National Grid are involved in a long-term project to build over 32km of new cable tunnels under South London to enable the replacement of existing electricity circuits. There will be 3 tunnels with various access shafts.

Our Involvement
We were commissioned to carry out the secondary lining of a 13m deep access shaft at Wandsworth. The project included:
 Completing the lining with the use of peri-formwork systems and steel re-enforcement.
 Ensuring water tight structure using Hydrotite on all joints.
 Responsibility for creating sink shaft using radius shutters of correct specifications.
 Our specialist concrete team ensuring in-situ pours ran smoothly with correct vibrations.

Challenges
A key challenge was working in a confined space for the works area. Liaison with other trades was essential to maximise our output and keep safety to a maximum.

Innovation
To ensure smooth progress of the project we created a climbing formwork system. This involves the formwork being designed so that it can be gradually moved up the walls of the shaft and fixed using a system of temporary bolts as the pour progresses.

Key Achievements
Works completed 3 weeks ahead of schedule.