Thurrock Viaduct

A complicated array of transportation infrastructure presents itself on the northern side of the Thames in Thurrock. At ground level, running east to west, is the double-track of the London, Tilbury, and Southend railway; passing above this at a perpendicular angle is the exit road from Dartford Tunnel; positioned diagonally over the latter is High Speed 1’s (HS1) Thurrock Viaduct; and finally, the highest of them all, is the ascending approaches to the Queen Elizabeth II Bridge. Of these, Thurrock Viaduct is the latest addition to a very dense industrial landscape, forming part of what was known as "Section 2" of the Channel Tunnel Rail Link (CTRL).

The 39-KM-long "Section 2" of the CTRL — running from St Pancras to Southfleet Junction — was officially given the go-ahead by the Government on 3rd April 2001. The 13-KM portion of this line between the portals of Dagenham and Thames Tunnels was termed the "West Thames" part of the CTRL construction project, formally known as Contract 310. Three viaducts, eleven bridges, road diversions, and extensive use of piled slabs and elevated piling were required for this stretch of the line, which would traverse the unstable ground of the Thames Marshes.

On 1st October 2001, Morgan Sindall Plc announced through a press release that they had been jointly awarded Contract 310, worth £178 million, with French firm Vinci Construction Grands Projets. Both companies had made a combined bid under the Eurolink name, Morgan Sindall Plc having done so through their construction division named Miller Civil Engineering Services Ltd. Preparation works were to begin immediately, with the first building work of the contract scheduled for March 2002. The contract was planned to be completed by December 2004.

Thurrock Viaduct extends for 1,025 metres and is threaded through the middle of a series of busy road carriageways. The structure comprises twenty-two concrete piers and has a deck formed of twenty-three individual spans. Of the latter, these are of reinforced concrete construction, each being made up of four segments cast on site. The first span was pushed onto the piers on 30th October 2002 (ref: Vinci Construction Grands Projets, Annual Report, 2003), and subsequent spans were similarly shifted forwards by hydraulic jacks, a process (known as "push-launch") which in turn moved earlier sections further across the site of the viaduct. The final span of Thurrock Viaduct was placed into position on 30th October 2003, exactly a year after the first was pushed out (ref: Vinci Construction Grands Projets, Annual Report, 2003), which involved pushing the entire deck of the viaduct forward, this weighing in at over 23,000 tonnes (ref: The Railway Magazine, January 2004). At this stage, Contract 310 was still on course for completion by December 2004.

7th August 2007

The inclined approach to Dartford Bridge is in the background of this view of Thurrock Viaduct, looking towards the Thames Tunnels. This is one of three viaducts situated between the portals of Dagenham and Thames Tunnels. © David Glasspool

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