Fehmarnbelt Fixed Link: building the world’s longest immersed tunnel

Currently, to reach the Danish port of Rødby from Puttgarden on the German peninsula of Fehmarn, the choice is limited to a 160 km detour by road or an hour-long ferry trip. Many opt instead to travel by plane between Hamburg and Copenhagen.

When the Fehmarnbelt Fixed Link is commissioned in 2029, Denmark will be just a 10-minute drive or a 7-minute train ride from Germany. The tunnel will make the train an attractive alternative to air travel. 

By further extending the road links between the Mediterranean and Scandinavia while enabling faster road and rail transport of freight between Scandinavia and Central Europe, the Fehmarnbelt Fixed Link will: 

• facilitate train travel, an environmentally friendly mode of transport
• boost tourism and trade between the two regions

Rising to the technical and technological challenge 

Unlike the Channel Tunnel, another project Group teams helped build over 30 years ago, the Fehmarnbelt Fixed Link will not be dug; rather, it will be positioned along the seabed.

That is why the various sections will be formed using prefabricated concrete segments. Although it is not the first time VINCI has employed the prefabrication technique, the sheer scale of this project makes it unlike any other. The tunnel will be composed of 89 segments, each 200 metres long, that will be towed and submerged, then assembled and positioned in a trench 40 metres underwater.

The segments will be transported by a catamaran specially designed to carry their weight – almost 73,000 tonnes – as well as their varying dimensions. A major mechanical challenge!

Before the segments are submerged, they will be placed on a bed of gravel that will form the foundation and installed using an automated forklift, controlled remotely.