The 217m-long element consists of nine segments, each 24m long. In total 79 elements of this type are required, and another 10 special elements with space for the technical installations.

The elements are being cast at the tunnel factory in Rødbyhavn.

The finished tunnel element will be left to cure for three weeks before the next stage begins – the installation of the steel bulkheads and ballast tanks to ensure the element’s stability during the immersion process.  

“It’s a special feeling knowing that we have now cast the first of the 79 standard tunnel elements. Casting such a large concrete structure has been a long and complicated undertaking, but we’ve now demonstrated that technology and methods interact well,” said Femern A/S CEO Henrik Vincentsen.

Now the first tunnel element has been cast, the experience gained from the casting process will be applied to the remaining elements. Data collection and preparation of the element will continue until the end of May.

“Casting a single tunnel element is a major achievement in itself, but we still have a long way to go. Nowhere else in the world does serial production of concrete elements of this size take place, but this is precisely what we have to master over the years ahead. Our goal is to transform the exceptional into routine practice,” said Fehmarn Belt Contractors (FBC) director Sébastien Bliaut.

The casting process will be optimised continuously as the work crew become more experienced. The second complete tunnel element is expected to roll off the production lines in mid-May.

FBC is currently excavating the portal and the tunnel trench where the first tunnel element will be immersed later this year. Dredging of the 18km-long trench for the tunnel was completed last month.

The Fehmarnbelt tunnel is both Denmark’s largest construction project and the largest construction site in northern Europe. The 18km-long tunnel beneath the Baltic Sea will connect Rødbyhavn on Lolland in Denmark and Puttgarden on the German island of Femern. It will be the world’s longest immersed tunnel.