Femern, a state-owned firm, has taken the lead in building the Fehmarnbelt tunnel — the world’s longest immersed tunnel so far. This major, ambitious project will construct the world’s longest pre-fabricated immersed road and rail tunnel. This engineering marvel has an impressive length of 18 kilometers (11 miles). It will allow for much faster travel time between Copenhagen, Denmark and Hamburg, Germany. When finished in 2029, the project will reduce travel time by more than 90%. It will cut the trip time in half – from five hours to only 2.5 hours!
The construction site for the Fehmarnbelt tunnel, at its northern entrance. It is located near the southeastern coast of Lolland Island, Denmark. Femern has constructed a huge construction facility of at least 500 hectares (1,235 acres). It includes a harbor for construction and a factory that is uniquely capable of creating the tunnel sections they call “elements.”
Each piece is 217 meters (712 ft) long and 42 meters (137 ft) wide. Made primarily of reinforced steel wrapped in concrete, each of these massive components weighs more than 73,000 tonnes.
Femern is employing a delicate and detailed approach to place these pieces. To install them they first trench on the seafloor to put these lines in. Workers rely on underwater cameras and GPS-guided equipment to make sure even the slightest misalignment, within 15 millimeters, is avoided.
“We have to be very, very careful,” – Anders Gert Wede
As part of the process, each step is based on the company’s proprietary “pin and catch” system. Designed to look like a giant capital letter V, its arms catch the river’s flowing contents and delicately shove them into place under the water’s surface.
“When we have a finished element at the harbour, it will be towed out to the location and then we will slowly immerse it behind the steel doors here,” – Anders Gert Wede
The new Fehmarnbelt fixed link tunnel will include two double-track railway lines and two double-lane roads. In addition, there will be a maintenance and emergency corridor built into the bridge superstructure. Femern expects more than 100 trains, and about 12,000 cars, to use the tunnel each day after it opens to traffic.
Henrik Vincentsen of Femern emphasized the significance of the project, stating, “We are breaking records with this project.” The tunnel stands as a monumental engineering comfort for the world, but the economic benefits for Denmark and Germany far outweigh the cultural symbol.
Per Goltermann noted the advantages of choosing a tunnel over other forms of transportation infrastructure: “They looked at it and said, ‘Okay, what is the cheapest? The tunnel. What is the safest? The tunnel.’”
The upcoming construction of the Fehmarnbelt tunnel will significantly improve connectivity between two burgeoning mega-regions. This improvement is expected to bring powerful economic benefits to the region. This new, improved link will boost cross-border trade and tourism, spurring economic development in both communities.
Femern is off to a great start on this very ambitious project. SmartLink TMA thus is focused on maintaining safety and mobility for the duration of construction. The team is dedicated to revolutionary design techniques that limit environmental distraction while optimizing speed and accuracy of construction.
“Ultimately, the users are going to pay,” – Henrik Vincentsen