Construction of the world's largest tunnel factory has been completed as part of the Fehmarnbelt Fixed Link road and rail tunnel between Denmark and Germany.
The factory at Rødbyhavn on the Danish island of Lolland, where the tunnel’s north portal will be, has an area of approximately 1Mm2 (including the dry dock) and is where the 89 precast concrete elements for the 18km tunnel will be manufactured. Once complete, it will become the longest immersed tube tunnel in the world, more than 10km longer than the tunnelled section of the Hong Kong-Zhuhai-Macau Bridge which currently holds the title.
The factory was aseembled by Femern Link Contractors (FLC) – a consortium featuring Vinci, Aarsleff, Wayss & Freytag, Max Bögl, CFE, Solétanche Bachy, Bam Infra, Bam International and Dredging International – which will be also be constructing the tunnel.
Of the 89 precast elements to be produced in the factory, there will be 79 standard elements that are 217m long, 42m wide and weighing over 73,000t. There will also be 10 “special elements” placed roughly every 2km that are 39m long, 47m wide, weigh 21,000t and have a basement underneath the road and rail surface.
The elements are created inside the factory by being cast onto large casting moulds and reinforced by steel. FLC successfully completed a trial of the casting process in July, creating a 12m-long prototype.
With the factory now complete, the contractor will look to start producing the full-size concrete elements before the end of the year. FLC board chairman Sébastien Bliaut told NCE earlier this year: “Once the learning curve is behind us, it will take nine weeks to make one tunnel element per production line.” At its peak, there will be six production lines working at once.
When an element is completed, it will be pushed out of the factory towards the dry dock. It is then sealed with bulkheads at each end and the water level in the dry dock is raised, leaving the element to float. Four tugboats then tow it into position, where ballast tanks inside the element will be filled with water to make it sink it into place. It is then covered in ballast concrete to and the bulkheads are removed from the openings, creating a watertight connection with the adjacent element.
You can watch the 10-month construction of the enormous precast factory compressed into a one minute timelapse video below.
The €7.1bn (£6bn) project is being overseen by Femern, a specially-created subsidiary of the Danish state-owned transport management firm Sund & Bælt. It is scheduled to complete in 2029.
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Tagged with: Aarsleff Bachy Soletanche bam Bam Infra Bam International CFE Dredging International Fehmarnbelt Max Bögl Solétanche Bachy Vinci wayss & freytag
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