New Tyne tunnel reaches a crucial stage

Jan 18 2010 by Tony Henderson, The Journal

Preparations for immersion will include connections to various winches and the installation of two 25m high towers on the unit.

One will provide access for workers. A survey tower will ensure that the team knows, with millimetre accuracy, exactly where the structure is when it is underwater.

Nicolas Caille, project managing director for Bouygues Travaux Publics, said: “This is a complicated and challenging part of the project, especially at this time of the year when the weather can be very harsh and the daylight hours are limited. We have highly specialised equipment and skilled divers in the river to make sure things go smoothly within this limited window.”

Paul Fenwick, project director for New Tyne Crossing promoter, the Tyne and Wear Integrated Transport Authority, said: “The floating and immersion of the tunnel units are major highlights in the project overall and represent a great technical achievement.”

The first unit to be immersed is located adjacent to Jarrow riverside, and will connect to a transition structure built on the river bank, which will link the river tunnel to the cut-and-cover tunnel beneath the land. Once all the tunnel units have been positioned beneath the Tyne, rock armour will be placed above them to protect the tunnel from potential damage.

The temporary internal bulk head walls and ballast tanks will be removed so that by this spring there will be clear passage from one side of the river to the other.

The new vehicle tunnel is due to open to traffic in February 2011, at which point the existing tunnel will close for major refurbishment.

Both tunnels will be operational by the beginning of 2012.