On the north bank

A new toll plaza is completed for southbound vehicles

A new toll plaza was built at the north end of the new tunnel for southbound vehicles. A re-configured toll plaza was constructed at the north end of the original tunnel.

A bus-only lane now allows southbound buses to bypass the toll plaza.

A roundabout where A19 and A187 traffic used to merge before reaching the original toll booths was removed.

Howdon Basin was filled in and handed back to the Port of Tyne.

The alignment of the new tunnel on the north was such that it passed over the existing 1967 tunnel. The vertical clearance between the two tunnels was only 2.7m and this required a different construction technique to ensure that there was no deformation of the main structure of the 1967 tunnel. To achieve this it was necessary to construct this section from the top downwards, i.e. build the roof to the new tunnel and then dig down to construct the base. The structure of the old tunnel was continually monitored for movement during and after construction of this section – excessive movement would have resulted in the tunnel being closed to traffic.

During construction, careful management of the land and associated pressure above the existing tunnel was implemented to ensure that construction of the new tunnel did not cause damage. Constant monitoring of the impacts on the existing tunnel took place during this part of the programme. Movement of the existing tunnel was well within acceptable parameters. Howdon Basin was filled in and handed back to the Port of Tyne.