Manufacture of ball-joint and foundation

With a diametre of ten metres the ball-joints are more than three times as big as the largest ball-joint ever used. The pedestals and shells were manufactured in the Skoda factories in the Czech Republic, which had the necessary skills and machinery to manufacture parts of this size. The cast-steel was poured into moulds, after which the parts were finished on enormous turntables.

The shells were transported to Hollandia in Krimpen aan den IJssel by ship, where they were attached to the core. Like the linking elements joining up the trusses, the shells are attached to the core by bolts.

The manufacture of the cast-steel shells had to be exceptionally precise. Even a minor deviation can result in a redistribution of the pressure, so that the pressure in certain points of the shell reaches impermissible levels, with potential failure. Manufacture of the shells was therefore subject to tolerances of just a few millimetres.