Construction of the world's longest underwater tunnel to be completed with special solutions

The world's longest underwater tunnel, 18 kilometres long, is scheduled to be completed by 2029, linking Central Europe and Scandinavia. The Fehmarnbelt tunnel will provide fast road and rail links, significantly reducing journey times between the two European regions. The construction has reached an important milestone: the 79 tunnels, which will be built using the PERI formwork solution, a well-known formwork solution in Hungary, are now being produced on five production lines, the company said in a press release.

They point out that once the project is completed, it will take ten minutes by car and seven minutes by train to get from northern Germany to Denmark, and that the Fehmarnbelt Tunnel, the largest infrastructure project in northern Europe, could be completed by 2029.

Submerged tunnel system

At 18 kilometres, it is the longest submerged tunnel system in the world, consisting of five tunnel corridors with a total width of 42 metres. Two of them will be used for dual carriageway roads, the other two will be used for rail traffic, but a service and escape route will also be built. The underwater motorway and dual railway will reduce journey times by about an hour in each direction compared to the current ferry crossing.

We have developed a unique formwork for the efficient and stringent safety production of tunnels 217 metres long and weighing 73,000 tonnes. Each module consists of 9 sections 24 metres long, and a total of 79 of these units will be used to build the tunnel

- said Miklós Izsiás, CEO of PERI Magyarország.

11 thousand tonnes of formwork delivered by PERI

The more than 11,000 tonnes of formwork material were produced in PERI's factories in Germany, Poland and Italy, and transported by twelve ships and more than 275 trucks to the centre in the Danish port of Rødbyhavn, where the 79 tunnels are now being produced in three halls on five production lines. Thanks to a special formwork solution, using around 3,300 cubic metres of concrete each, several segments have already been completed. After the initial phase, the production lines will be converted to continuous series production. After production, the segments will be transported by sea to their place of immersion and sunk. 

Not an ordinary project, but standard solutions will also play a role

As the brochure points out, in addition to the specific formwork system, the PERI engineering team is helping the project with several standard solutions: the PERI UP modular racking system is adaptable to the individual steel formwork and allows safe access to the production lines, while the PROKIT fall prevention grid provides reliable protection against accidents. Concrete pressure monitoring is supported by the PERI InSite Construction's measuring device and sensors, which also allow efficient testing of concrete temperature and maturity. 

Finally, the company emphasises that thanks to the precise logistics concept developed by the PERI team, deadlines can be met accurately, and regular maintenance ensures that production lines can operate at maximum capacity. The announcement concludes by reminding readers that the PERI team has already contributed to the successful construction of numerous tunnels: their engineers played an important role in the construction of the recently completed Sopron tunnel in Hungary, which is part of the M85 motorway (you can read several articles about the tunnel in our newspaper here).