TfL is replacing the three span Power Road Bridge, which carries the A406 North Circular Road (Gunnersbury Avenue) over two Network Rail lines. This complex project involves diversion of utilities onto a new service bridge, and highway bridge deck demolition and replacement works without the need for road closure.
The need for replacement
The bridge has reached the end of its operational life and is beyond simple repair. Not replacing the bridge would mean restricting the weight of vehicles that use the bridge and closing lanes to carry out maintenance, causing considerable disruption to traffic and rail operations in the long term.
The £35m bridge replacement works are part of TfL’s Road Modernisation Plan. This project is one of eight in the STIP portfolio that are being delivered in partnership with Hochtief (UK) Construction, Ramboll and Parsons Brinckerhoff (JV), and Skanska.
The new structure
The new structure replacing the existing bridge will have an expected design lifespan of 120 years.
The new bridge will have wider footways and better facilities for pedestrians and cyclists making this section of the A406 safer for all users.
Key phases of the work
The project is divided into three key phases:
- Preparation and installation of a utilities service bridge (May to July 2016)
- Diversion of utilities into the service bridge (from July to December 2016)
- Highway bridge deck demolition and replacement works: The main bridge replacement works (December 2016 to December 2017)
A new service bridge for utility cables and pipes
Advance works to replace Power Road Bridge involved the installation of a new utilities service bridge in July 2016. The service bridge was lifted into position by two 500 tonne cranes in a tandem lift during a closure of the railway and contraflow traffic arrangement on the A406 Gunnersbury Avenue.
The next phase of work is the diversion of the utility cables and pipes (electricity, gas, water, and telecommunications) from the existing Power Road Bridge carriageway into the new service bridge. This will minimise the need for road closures for future maintenance works on the utility pipes and cables.