The bunker was part of the Nieuwe Hollandse Waterlinie, a series of works constructed before World War II to defend the Netherlands against foreign invasions.

Because the bunker is an important piece of historical heritage, Rijkswaterstaat wanted to move the heavy concrete building in one piece.

The gantry was put in place to support the weight of the bunker, allowing contractor Sas van Vreeswijk to disconnect the building from its foundation. After the bunker was detached, Mammoet was able to transport the 1,200t structure 150m to its new location.

At its new location, the bunker was turned and positioned onto the new foundations at an angle. It was placed into the landscape as an ‘Objet Trouvé’- an object found by an artist and displayed with minimal alteration as a work of art.

Mammoet used a combination of a skidding system and four strand jacks to rotate the bunker. By lowering two strand jacks while two other strand jacks held still, the bunker could be rotated while its center of gravity remained stationary.

“The project was a challenging assignment for Mammoet. The bunker was designed to withstand bombing raids, so our client had to bring in a special drill that could drill through the reinforced concrete, enabling it to be attached to the gantry. The team also had to create a road between the old and new locations to ensure that the transport would not get bogged down in muddy ground during the operation. In addition, the bunker had to be positioned at an angle, to highlight to everyone who passes the bunker that it has been moved,” Mammoet said.

Mammoet said more than 2,000 people went to witness the operation.

The bunker is not the only object that will be moved to make way for widening the channel. In total, Mammoet and Sas van Vreeswijk will be moving three bunkers and two water management structures during the upcoming months.