Lantis and contractor TM Cotu have started flooding the construction dock in Zeebrugge to transport the elements for the Scheldt Tunnel to Belgium.
The immersed tunnel’s eight elements, which have taken two years to construct, are now ready to be transported to Antwerp where they will create a new crossing beneath the Scheldt River. The tunnel is a key part of the city’s new Oosterweel ring road.
Flooding of the construction dock, which is approximately 900x150m, began last week. It will take approximately seven days to fill the area with 800,000m³ of water – the equivalent of 320 Olympic swimming pools.
Lantis project manager Bert Claeys said filling the construction dock was needed to be done slowly.
“This allows us to regularly inspect the tunnel sections for any leaks. As soon as the dock is completely under water, the tunnel sections disappear from view. A special moment, because it is one of the last times that we can see the tunnel sections that we have worked so hard on,” he said.
The next step is to remove a section of the dyke so that the tunnel sections can leave the dock. This will only happen after the dock is filled with water.
“By filling the dock first, we create a water buffer. This prevents the canal water from suddenly and uncontrollably flowing in when we open the dyke, and everything proceeds safely and in a controlled manner. We used the same method for the dyke breach on the Left Bank,” said Claeys.
The tunnel sections must not only be watertight, they must also be able to float and sink. This is important for their transport and for when they are lowered into their final location in the Scheldt. In recent months, each tunnel section has therefore been equipped with five ballast tanks – two 3,000m³ tanks of and two 1,000m³ tanks. They are connected to a pipe system to accurately regulate the weight and buoyancy of the tunnel sections. The ballast tanks were also filled with water while the construction dock was being filled to ensure the elements remain stable on the bottom until the moment of departure.
The first of the tunnel sections, which each weigh up to 60,000 tonnes, is scheduled to start the 100km journey to Antwerp on May 19.
Each tunnel section will travel from Zeebrugge to the Doel Dock in Antwerp in approximately 30 hours, with stops in the Zeebrugge outer harbour and in Terneuzen to wait for high tide.
Placing the elements in their final position is dependent on tides and the weather. The elements will remain in the Doel Dock until a neap tide occurs and they can be sunk into position. The first element will be immersed in early July and all eight tunnel elements should be in place by the end of the year.
The Scheldt Tunnel consists of two tubes for car traffic, a 6m-wide tube for bicycles and an emergency tunnel.
Cyclists will be able to use the tunnel from 2028 and it will open to vehicles in 2030. The entire Oosterweel connection will open in 2033.
TM Cotu Belgian construction groups Besix, Stadsbader Contractors, Deme and Jan De Nul.
