Work Completed on World’s Longest Hydraulically Inserted Pipe
(UC) — Construction of a 5km (3-mile) replacement tunnel 30m (98 feet) under the River Humber completed last year and now, in the penultimate stage of the project, the last piece of gas pipeline has been inserted.
Working with project partners Skanska, A.Hak and Porr, the 3.65m (12 foot) diameter tunnel was built 30m under the river to replace a trench-laid gas pipe which had become exposed. When gas begins to flow through the pipeline towards the end of this year, it will help ensure reliable and resilient supply of up to 25% of Britain’s gas.
Two hydraulic thrust machines began the epic task of carefully pushing eight 620m (2,000-foot) long and 850 tonne sections of pipe on rollers into the new tunnel from Goxhill side of the Humber on June 23. The pipes were methodically pushed at around one meter per minute into the tunnel which had been flooded with 50,000 cubic meters of pure and treated water, enough to fill 16 Olympic swimming pools, to aid the installation.
After one pipe section had been installed, the next was moved into position and welded to the one in front. The push continued until all five kilometers of pipeline were fully installed on July 9, becoming the world’s longest hydraulically inserted pipe.
“Completing the installation of the pipeline under the Humber is a major milestone for both the project team and partners,” said Steve Ellison, Senior Project Manager, Capital Delivery, for National Grid. “We will now begin work to connect the pipeline to the network, ready for gas to begin flowing towards the end of the year.”
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