Castle jacking

Castle jacking

Commissioned by: Strukton Infratechnieken
Location: Utrecht, Netherlands

Reinforcing the castle foundation with supporting poles without damaging the walls and the surrounding area. Commissioned by Strukton Infratechnieken, Holmatro supplied multi purpose cylinders for jacking the castle.


At the beginning of the previous century a new castle, named "Kasteel de Haar" was built on the foundations of a seventeenth century fortress. This foundation turned out to be too weak to support the new and massive building. The castle started subsiding in the mid nineties and the only way to save it, was to reinforce its foundation.


Sinking piles into the ground for extra support was not an option: There simply was not enough space and it would disturb the ground too much, resulting in more damage. Therefore another approach was needed and it was decided to fit the castle’s foundation with supporting poles.


(1) Steel tubes were drilled into the ground on both sides of the castle walls. At the same time a mixture of cement and water was pumped in. Thus, the soil was not being removed, but blended with the mixture. When the tubes were drilled in deep enough, (2) a hole was drilled in the wall, (3) and a steel H-profile was positioned through it, resting on the tubes. On top of this a load spreading plate was fixed. (4) By means of multi purpose cylinders the H-beam was put under pressure. (5) Then, the resulting gap between the tubes and the beam was filled up with steel plates. (5 + 6) The surrounding floor and any gaps in the walls were filled up with concrete.

Castle jacking

The result: a fully supported, stable and safe structure. Once this major project was finished, the wall and surrounding area showed no indication of the work that had been undertaken.

Would you like to know more about this project? Contact us via e-mail or call +31 (0)162 751500.

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