On request of the Ministry of Justice, the Central Government Building Authority tendered for design and construction of two floating prison buildings in 2005.
The design of the prison buildings was performed by EGM architects.  The basement of the building, which is the floating foundation, was separately tendered for in a ‘Design & Build’ setting. Special requirements were made on issues regards the maintenance of the floating structure and some functional and safety aspects.
Royal Haskoning (structural design and construction supervision), Ursem Bouwgroep (main contractor top structure), Besix (contractor pontoon), Imtech (contractor installations), and Hacé Marine (nautical consultant), succesfully designed and completed the project within time and budget.

 
The design is remarkable for its partially prestressed concrete construction and its double walls. The pontoon is 100 meters long and 20 meters wide, and reaches 3.5 meters in depth. The floors and walls are a solid 30 and 25 centimeters and are fully watertight. To minimalize the weight, the deck is made of lightweight concrete. The internal area is 1600 m2 gross area, and can be used for recreation space and meeting space, and for installations and storage.
The pontoons have been constructed in an open pit and transported over waterways to the assembling and fit-out site. The pontoons are fitted with ballast tanks to facilitate this and future  transportation.
The two floating prisons are identical, each 8000 m2 gross floor area, and are presently in service in Zaandam.





 

Dirk Jan Peters
T +31 (0)24 3284 153
E Dirk Jan Peters