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Bjorvika Immersed Tunnel, Oslo

The facts

Client:   Norwegian Public Roads Administration
Location:  Oslo, Norway
Services:  feasibility, outline and detailed tunnel design
Sector:   Infrastructure
Project Value:  €300m
Start/Completion: 1997 - 2010

The Project

The Bjørvika Immersed Tunnel is the first in Norway and Capita Symonds has been involved with the project since 1997 when we first provided advice on the feasibility of the scheme. 

This was followed up with outline design and detailed design of the tunnel structure, working with Norwegian consultants Aas Jakobsen. We assisted in the preparation of the contract documents and have subsequently provided advice and site support during the construction phase.

The immersed tube tunnel technique is highly specialised and Capita Symonds is one of only a few consultants in the world with the necessary expertise to deliver such projects. The method involves the construction of large box shaped tunnel elements in dry docks or purpose built basins, which are sealed with bulkheads then floated up and towed to site where they are sunk into a pre-dredged trench in the river or sea bed. The tunnel elements are joined together with a complex arrangement of watertight gaskets and once backfilled, the road or railway can be constructed internally.

The immersed tunnel in Oslo is 600m long and will carry a dual three lane highway under the harbour. It is part of a much longer network of tunnels carrying traffic beneath the city on the E20 highway. The overall scheme cost is in the order of €300m, with the immersed tunnel contract being worth €124m. The client is the Norwegian Public Roads Administration and the contractor for the immersed tunnel is a joint venture of Skanska, BAM and Volker Stevin.

The tunnelling contract is linked to the opening up and redevelopment of the harbour area, which includes a new opera house, commercial and residential districts. The project still has a long way to go however, as once all of the tunnel elements are in place there will be a lengthy period for finishing the road construction within the tunnel and fitting the mechanical and electrical systems required for safe operation. 

The tunnel should be open to traffic in 2010 with the remainder of the harbour development planned to be complete around 2012.