London’s M25 ring motorway suffers some of the worst peak time traffic congestion in the country. To demolish and replace the worn out road deck of the Dartford Tunnel, during a series of night-time possesions, posed a huge challenge to engineers. Using a multitude of techniques, sections of the road deck were cut, lifted and replaced over a 91/2hr period in order for the tunnel to be open again for the morning’s rush hour traffic. Using a gantry lifting frame and hydraulic jacks, 6.8m long sections of the deck were removed. New match cast units were then delivered back to the lifting gantry using a specially adapted turntable truck and then fixed in position and secured.
Judging Panel’s Comments: The award goes to a project which impressed the judges as huge logistical problems had to be overcome enabling a road deck of an existing road tunnel to be systematically removed and replaced within a time window, enabling continued use of the tunnel by the owner during high traffic periods. With innovative ideas and considerable effort the project more than achieved its objectives to the benefit of all concerned.
