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tech 11 May 2026

First Element of the Fehmarnbelt Tunnel Successfully Immersed

The Fehmarnbelt Tunnel, connecting continental Europe to Scandinavia, has reached a significant milestone with the successful immersion of its first element. This 18-kilometer project will become the world's longest immersed tunnel.

Article inspired by the original source
First tunnel element of the Fehmarnbelt Tunnel immersed ↗ www.arup.com

Introduction

The Fehmarnbelt Tunnel project recently reached a significant milestone with the successful immersion of its first tunnel element. Located between the Danish island of Lolland and the German island of Fehmarn, this 18-kilometer immersed tunnel is set to become the longest in the world, far surpassing San Francisco's 5.8-kilometer Transbay Tube.

An Ambitious Project for Europe

The Fehmarnbelt Tunnel represents a significant technical advancement, connecting continental Europe to Scandinavia and drastically reducing travel time for passengers and freight. Once completed, it will offer a high-speed route between Stockholm and Hamburg, increasing the attractiveness of eco-friendly trains over freight trucks.

Technical Challenges

The immersion of the first tunnel element required meticulous preparation and exceptional international collaboration. The RAT joint venture, comprising Ramboll, Arup, and TEC, has been closely working with the client Sund & Bælt since 2008 to provide their technical expertise. Three main contracts structure this project:

  1. TPR Contract: It concerns the tunnel entrances and approach structures, including the cut-and-cover sections, portal buildings, and access ramps.
  2. TDR Contract: It covers site preparation, including dredging of the tunnel trench and creating temporary working ports.
  3. TUX Contract: It focuses on the immersed tunnel itself, with tunnel elements constructed on land, then transported and submerged.

Key Figures

  • 18 kilometers total length of the tunnel
  • 79 standard tunnel elements and 10 special elements
  • Each standard element measures 217 meters long

Environmental and Economic Impact

Beyond the technical challenges, the Fehmarnbelt Tunnel is designed to be environmentally friendly. By facilitating rail transport, it helps reduce carbon emissions. Economically, it is expected to boost trade and tourism between the connected regions.

Conclusion

The immersion of the first element of the Fehmarnbelt Tunnel is an impressive achievement that showcases ingenuity and international collaboration. If you're considering an ambitious tech project, let's discuss your project in 15 minutes to turn your ideas into reality.

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Fehmarnbelt Tunnel immersed tunnel European infrastructure RAT Joint Venture environmental impact
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