Bouygues must construct a 2.6km two-lane road tunnel comprising two cut and cover sections north and south of the Tyne with a central 360m long immersed tube section.
In the scheme designed by TWPTA's advisers Arup and Royal Haskoning, three 100m and one 60m long sections will be constructed in a dry dock on the north bank of the Tyne .
The concrete sections are rectangular and will measure 14m wide by 9m deep with 1.5m thick walls.
When the first two sections are complete, the dry dock will be flooded allowing them to be floated out. The process will be repeated for the second pair of sections.
The sections will then be pumped full of water and sunk into a pre-dredged channel, allowing them to be placed in a controlled manner.
They will then be connected and the tunnel de-watered.
Dredged material will be used to cover the tunnel with rock armour which will protect it from trailing ship anchors.