The units were constructed in a formerly derelict dry dock at the Wallsend and floated the 3km down the Tyne before being sunk into a prepared trench adjacent to the existing tunnel.

We had to prepare the base of the dry dock by levelling and profiling a sand and gravel formation layer prior to laying ply boards.

Each of the 8600t tunnel sections were 90m long by 15m wide and 8.5m high and had three cavities: -

• Main Vehicle Access
• Emergency Escape Route and
• Services Tunnel

The walls and roof pours took 16 hours to complete and required specially designed cooling systems within the pours to control heat loss/gain and any subsequent cracking.

We have delivered the project on programme and within the client's specified budget.'

Key Quantities include:

• 100 Strong Workforce
• 14,400m3 of Concrete and
• 3,400 tonnes of reinforcement