Highways Agency - Safe roads, Reliable journeys, Informed travellers

The Dartford - Thurrock River Crossing

A Growing Need

In 1929, Kent and Essex County Councils promoted a Bill for the construction of a tunnel. A pilot tunnel was authorised in 1936 and completed in 1938. The Second World War prevented progression of the full bore tunnel and the County Councils could not revive their plans until 1955.  

The first Dartford tunnel was built at a cost of £13 million and opened to traffic in November 1963. Early estimates of 2 million vehicles a year more than doubled in the first year of operation. Very quickly it was realised that a second tunnel was needed. The second tunnel took eight years to build and opened to traffic in May 1980, at a cost of £45 million.

When the M25 was completed in 1986, the tunnels provided a vital link in the national road network. Very soon the daily average volume of traffic regularly exceeded the maximum designed capacity of 65,000 vehicles and forecasts predicted annual throughput in excess of 40 million vehicles. Clearly something had to be done to increase the capacity and meet the traffic demands well into the next century.

As the operation of the Dartford Tunnel was controlled by an Act of Parliament, new legislation was necessary to allow transfer of the crossing from Kent and Essex County Councils to Dartford River Crossing Limited. This process was completed on July 31st 1988 and construction of the bridge began just a few days later.

 The principal engineering contractor was the Cementation Cleveland Dartford Consortium, a joint venture between Kvaerner Construction Limited and Kvaerner Cleveland Bridge Limited. Dr. Ing Hellmut Homberg and Partner designed the cable-stayed bridge superstructure whilst Kvaerner Technology Limited designed the substructure.

It took three years to build the new bridge and many challenges and obstacles had to be faced along the way, such as co-ordinating the work around changing water levels and the river traffic of a busy tidal waterway.

The new bridge at Dartford was named The Queen Elizabeth II Bridge and was officially opened by Her Majesty in October 1991. It was the first bridge to be built at an entirely new location along this historic river for more than 50 years. Now as you travel the approach roads towards the Dartford River Crossing, the new bridge rises dramatically into view; the largest and most dominant feature on the horizon.

Beneath the waterline, the bridge rests on two reinforced concrete foundations of enormous physical bulk and mass, each the equivalent in volume of 400 double-decker buses and weighing a total of 85,000 tonnes. These structures, which are called caissons, were constructed at a dry dock in Holland and towed across the North Sea by tugs on a 150-mile journey to the River Thames. Here they were sunk into position on either side of the navigation channel. On these sit slender concrete piers, 53 metres in height, which meet the underside of the steel pylons just below road deck level.

Traffic travels across the bridge on a four-lane carriageway, reaching 65 metres above the river at its highest point between the two main piers. The 450 metre main span is flanked by two 181 metre long back spans which extend to the riverbanks, which are in turn flanked by 1-kilometre approach viaducts on either bank. These link the high level roadway over the river directly to the road system on the north side, and the toll collection plaza and the road system on the south side. The total length is 2.9 kilometres long.