The dome roof, with a clear span of 57 metres, consisted of 8 main trusses 32 metres long, 1.80 metres high and 0.26 metres thick, each weighing approximately 8.5 tonnes. Purlins interconnected the main trusses that converged in the top structure.
A complex roof construction that had to be dismantled in sections and then rebuilt. Lifting and dismantling the last four old main trusses and rebuilding the first four new main trusses presented the biggest challenge.
The Wagenborg Nedlift lifting specialists worked hard to come up with a safe and efficient solution to remove the last four main trusses one by one.
The engineers from Wagenborg Engineering were called upon to calculate the different variants for this complex lifting operation that involved several cranes lifting simultaneously.
This resulted in a sound action plan for the deployment of two 400-tonne mobile cranes and one 300-tonne crane. The 300-tonne crane and one 400-tonne crane each had a main truss in the hook, enabling the other 400-tonne crane to lift a main truss over the masts of the other cranes. After the 400-tonne crane had lifted the 4th and 3rd truss, the other cranes removed the last two trusses.
Installing the new trusses was carried out in reverse order. After installation of the main trusses, the big mobile telescopic cranes were replaced by two Spierings AT-6 type mobile tower cranes. This made it possible to install the cross beams, the top structure and the glass constructions in a safe set-up using different lifting heights.
Plenty of rigging challenges presented themselves due to the specially-designed payloads.
All in all, impressive workmanship and cooperation from the Wagenborg Nedlift team!