The Dartford River Crossing links the Essex and Kent sections of the M25 Motorway and consists of two tunnels and a bridge.  The main elements of the project are the replacement of the East Tunnel carriageway deck and strengthening of the Essex Viaduct support piers.

TGP was appointed by the contractor as temporary works consultant.  The brief included the mechanical and structural design of the tunnel deck slab erection gantry propping to the Essex Viaduct deck.

The gantry was designed to operate within the height and width restrictions imposed by the tunnel and was used to remove the existing deck slab and install the new 45 tonne slabs.