Femern Bælt Senketunnel mellom Danmark og Tyskland

Verdens lengste senketunnel

The Femern Bælt project is a major infrastructure endeavor designed to connect Rødbyhavn in Denmark with Fehmarn in Germany via an 18-kilometer-long immersed tunnel under the Baltic Sea. This tunnel will be the world's longest immersed tunnel and will accommodate two motor vehicle lanes with two lanes in each direction as well as two railway tracks, one in each tunnel bore. The total estimated cost of the project has increased over time, with the most recent estimate exceeding 86 billion Norwegian kroner (approximately 7.4 billion euros).

Produksjon av store elementer

Construction involves the production and installation of 89 massive concrete elements at a purpose-built facility covering over one million square meters in Rødbyhavn. These include 79 standard elements and 10 special elements, each measuring 217 meters in length, 42 meters wide, and 9 meters tall. Each element weighs around 73,000 tons, with the entire project requiring approximately 3.2 million cubic meters of concrete and 360,000 tons of reinforcing steel. Once cast and tested, these tunnel elements are outfitted with ballast tanks and steel bulkheads before being floated out to a pre-dug trench on the seabed, where they are carefully lowered and joined underwater to form the tunnel.

Konsortium og fremdrift

The client for the project is Femern A/S, a wholly owned subsidiary of Sund & Bælt Holding A/S under the Danish government. Construction is carried out by the Femern Link Contractors (FLC) consortium, which includes prominent European construction companies such as Vinci Construction (France), BAM (Netherlands), Per Aarsleff A/S (Denmark), and Max Bögl (Germany). Technical advisory services are provided by the Design Joint Venture (DJV), a collaboration between Rambøll, Arup, Cowi, and TEC. The project started construction activities in 2021, with the original opening target set for 2029.

Forsinkelser på spesialfartøy

Despite steady progress on associated Danish railway infrastructure, including approximately 110 kilometers of new double-track railway between Ringsted and Rødby, the project faces significant challenges. Particularly, the custom-built specialized vessel named IVY, which is critical for the placement of tunnel elements, has experienced substantial delays due to technical issues and has yet to pass full testing or receive regulatory approval, resulting in an estimated delay of about 18 months that may affect the overall timeline.

Geotekniske og miljøutfordringer

Additional technical challenges include geotechnical findings that parts of the tunnel trench are approximately 30 centimeters deeper than initially planned, necessitating extra leveling with gravel to ensure a stable and secure foundation for the tunnel. Environmental approvals remain critical, especially from German authorities, who have expressed concerns over underwater noise and sediment dispersion during construction. German environmental organizations have threatened legal actions, which has contributed to project uncertainty and risks of further delays.

Økonomiske risikoer og fordeler

From a financial perspective, delays pose considerable risk, as external analyses estimate that each year of postponement could cost around 500 million Danish kroner in additional expenses, including compensation demands from contractors. Thus, the project is subject to both technical and regulatory risks that could impact its scheduled completion and budget. Meanwhile, the extensive infrastructure connection promised by the Femern Bælt tunnel is expected to bring significant societal benefits by improving transport connectivity between Denmark and Germany, fostering economic integration, and supporting sustainable mobility solutions in the region.