On Tuesday 16 September 2025, BESIX and its partners in the TM COTU joint venture successfully immersed the fourth tunnel element of the Scheldt Tunnel beneath the River Scheldt in Antwerp, Belgium. This achievement marks a significant milestone in the construction of the Oosterweel Link, a major infrastructure project that will complete the Antwerp Ring and greatly enhance mobility and liveability in the region.
Successful second attempt
The operation followed an earlier attempt a few weeks ago, which was interrupted due to an unexpected build-up of sand on the riverbed. At that time, the tunnel section had already been connected underwater to the third element using a specialised rubber seal known as the GINA joint. The COTU team had to carefully detach the section and refloat it, a delicate task that was carried out smoothly thanks to thorough preparation, technical expertise and composure.
The team then returned the element to the Doel Dock and waited for neap tide, a period when water movement is minimal, to ensure ideal conditions for a second attempt. This time, the immersion proceeded without issue, and the fourth element is now securely in place on the riverbed.
One-month pause
With the fourth element installed, the immersion process enters a planned one-month pause. During this time, the navigation channel will be shifted from the right to the left bank, allowing the next tunnel sections to be immersed safely on the right bank.
Meanwhile, the COTU team has begun transporting the remaining four tunnel elements from Zeebrugge, where they were constructed, via the North Sea and the Scheldt River to Antwerp. The fifth element is scheduled for immersion on 16 October, subject to favourable conditions.
Preparations on the Right Bank
Meanwhile, on the right bank, the COTU joint venture is removing the last bit of soil separating the tunnel entrance from the Scheldt. This will make way for the final tunnel section, which will connect to the entrance at the future Oosterweel junction. This junction will link the Antwerp Ring Road to the port area.
Until now, the soil has served as a protective buffer for passing ships. Once the navigation channel is rerouted, vessels will no longer sail close to the site on the right bank, allowing the removal of the temporary dike and further progress on the tunnel entrance.
Vital component of Oosterweel Link
The Scheldt Tunnel is a vital component of the Oosterweel Link. Once completed, it will provide a new crossing under the Scheldt for motorized traffic, cyclists and emergency services. The tunnel includes two traffic tubes, an emergency tube and a six-metre-wide cycle tube.
BESIX is proud to contribute its expertise to this landmark infrastructure and to share knowledge with international partners shaping the future of mobility.
TM COTU stands for "Tijdelijke Maatschap Combinatie Oosterweeltunnel" and brings together the Belgian construction groups BESIX, Stadsbader Contractors, DEME, and Jan De Nul.
The immersion schedule is subject to change and depends on several factors, including weather, wind, wave conditions, currents and tides. You can follow all important operations via the live blog www.kanjersopkomst.be.
