Gigantic sawing and lifting operation crucial part on Oosterweel connection

The Oosterweel link is currently the largest and most far-reaching infrastructure project in Belgium. The project is initially intended to close the Antwerp Ring Road on its northern side, but at the same time creates the necessary breathing space on and off the road. Part of this extensive project is the construction of a highway tunnel with an adjacent bicycle shaft under the Scheldt. Preparatory work on both banks of the Scheldt is already in full swing. And in those deep construction pits, the expertise of the Dutch demolition company Van der Jagt Groep comes in handy.

Temporary Partnership Combination

Oosterweeltunnel (TM COTU) is taking on the construction of the Scheldt Tunnel. The group consists of the Belgian construction groups BESIX, Stadsbader Contractors, DEME group and Jan De Nul. On the Left Bank, the tunnel tour is already taking shape. At the end of August last year, the deepest point in the construction pit was reached at a depth of 25 meters and since then the consortium has been busy with the concrete work. "On the Right Bank, the construction pit is formed by anchored diaphragm walls containing stamping frames on three levels. Via six heavily reinforced concrete beams of 430 tons each, the transfer from the strut frames on either side is distributed to the diaphragm walls," explains Adriaan van der Jagt. "Like the strut frames, the concrete beams are temporary in nature and will be removed in phases with the construction of the ramp. And we are taking care of that complex task."

Too heavy and too long

TM COTU approached several parties for the phased removal of the six heavily reinforced concrete beams. "We may not have been the cheapest, but the consortium had the most confidence in our method," says Adriaan. "This complex project requires a combination of disciplines and techniques, since the concrete beams cannot be lifted out in their entirety. They are too heavy and too long for that. Traditional demolition was not an option either, because that would damage the couplers used to anchor the diaphragm wall. We devised a method in which we support the beam with an auger construction, then saw it off the back of the diaphragm wall and move it to the middle of the cofferdam via a sliding conveyor. Here we then have all the space we need to cut the beam into 70- to 120-ton blocks and lift them out with a 750-ton crane between the strut frames above." 

Combination of techniques 

The proposed method proved extremely successful, because after pouring the concrete floor in the construction pit, Van der Jagt Group removed the bottom two beams in early April. The beams are mega heavily reinforced, 18 meters long, 2.5 meters deep and 3 meters high. "We were working day and night with three bandsaw combinations to saw over 250 m2. Within three weeks, the concrete blocks had to be removed from the construction pit, all residue cleaned up and the final touches put on the 'i'. Quite a feat. After sawing, we removed the last remnants of both beams against the wall with hydrodemolition (water demolition)." According to Adriaan, it is definitely a very special job for Van der Jagt Group. "This kind of project is right up our alley. It's special, big and it has to be fast. Everything comes together here. That makes us happy. We therefore take the complete package out of TM COTU's hands from A to Z."

The two concrete beams on the next level are scheduled to be removed by Van der Jagt Group just before the summer vacation, when the roof of the ramp is poured. The last two beams are due in February 2025.