“There’s a Light at the End of the Tunnel"

The placing of the final sections of the second Tyne road tunnel in Newcastle is described. The 1.6 km tunnel, which will eventually carry southbound traffic, has required a variety of tunnelling techniques. The 360 m main crossing uses an immersed tube made up of four elements which have been constructed at the nearby Neptune dry dock. The construction of the elements, each 90 m long and 15 m wide, is outlined. Tubes are built to the same profile as the river bed and each contains 10,000 tonnes of concrete. Details are provided of the transport and positioning of the elements, processes restricted by the state of the tide. Trenches were excavated in 2009 with the material being used for infilling a dock as part of a redevelopment plan. Elements are lowered at night with the aid of divers and connections made using pressure. Details are given of the cross section of the tunnel which is only the third immersed tube to be built in the UK.