Grandstand Ahoy is a facility for sport events, fairs and concerts. Especially because of the concerts a greater height of the roof and a stronger roof was required in order to accommodate large and heavy stage scenery elements. Ahoy also wanted to expand the capacity for visitors by adding a new tribune between the grandstand and an adjacent building.
The challenge was to realise this while the building remained maximally in use. A program free period of about a half year was the maximum feasible. In this period the new roof had to be assembled and the central zone had to be renovated. Prior to this it was possible to do some phased construction work in the edge zones of the building.

Project information


Building structures




Municipality of Rptterdam


Zwarts & Jansma

Project size

25.000 m2 GFA

Start of project




Consulting services

Structural design, specifications, detail drawings and calculations

The obvious approach was to take of the excising roof and to install a new roof. But, then the central zone would be exposed to weather conditions and it would be impossible to work there. In this way the planning would not be feasible. Aronsohn introduced an approach in which the new roof with trusses of 90 m length was constructed above the old one. After this the old roof could be demolished from inside. In this way the building remained watertight all the time. It introduced several critical building phases that had to be checked. In the end it was a very successful approach.

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