First segment of the Fehmarnbelt Tunnel is in place

An important step in one of the largest infrastructure projects currently underway with German involvement: the first segment of the Fehmarnbelt Tunnel has been submerged off the Danish port city of Rødby.

“After a lowering process lasting several days, the first of a total of 89 concrete elements for the Fehmarnbelt Tunnel is now lying in the tunnel trench on the seabed and is connected to the Danish tunnel portal,” Femern A/S announced. The Danish company is the client for the project. The operation took several days.

The transfer of the tunnel element from the factory's work harbor, where the segments are manufactured, to the construction site began as early as Monday evening. Five tugboats brought it to a ship specially designed to lower the segments to the bottom of the Baltic Sea.

However, work was delayed due to the current. It was only on Wednesday afternoon that the lowering could begin, reported Tagesschau.

The complex maneuver took 14 hours

The lowering of the tunnel segment took 14 hours. “This is a very complex maneuver that has never been carried out on this scale before,” said Lasse Vester of Sund & Bælt. Sund & Bælt is the parent company of Femern A/S. Both companies belong to the Danish Ministry of Transport.

The tunnel will consist of 89 segments, which will be submerged in a 12-meter-deep trench on the seabed of the Baltic Sea. Such a component is 217 meters long and 42 meters wide. It weighs 73,500 tons and is additionally ballasted with 4,500 tons to ensure it sinks. It comprises four tubes, two each for rail and road traffic, as well as a rescue tube.

The individual segments must be lowered with an accuracy of a few millimeters. They are then connected, and the trench at the respective location is filled with stones and gravel to stabilize the segment in its position. Finally, the tunnel will be covered with a protective layer of large stones and a layer of sand to restore the seabed.

Sund & Bælt already has experience in building such immersed tunnels: the Drogden Tunnel, which is part of the Øresund connection between the Danish capital Copenhagen and Malmö in Sweden, opened in 2000, was also built using this method. Nevertheless, this project is more complex: “The elements of the Fehmarnbelt Tunnel are longer, heavier, and wider than the elements used in the construction of the Øresund connection, and we will be working in significantly deeper water in the Fehmarnbelt,” explains Vester.

Crossing the Belt in 7 minutes

The approximately 18-kilometer-long Fehmarnbelt Tunnel crosses the Fehmarn Belt and will in the future replace the ferry connection between Puttgarden on the German island of Fehmarn and Rødbyhavn on the Danish island of Lolland. Crossing the strait will then only take 7 minutes by train and 10 minutes by car. The ferry takes about 45 minutes without waiting time.

The opening of the tunnel was planned for 2029. However, completion is expected to be delayed by approximately two years. One reason is that the construction of the special ship took longer than planned. There are also delays on the German side: a tunnel is to be built there between Fehmarn and the mainland so that traffic does not flow over the Fehmarn Sound Bridge, built in the 1960s. However, the 1.7-kilometer-long Fehmarn Sound Tunnel is currently scheduled to be completed only at the end of 2032.

As with almost all infrastructure projects in Germany, there have been strong protests and lawsuits against this one as well.

(wpl)