At the Rokin in Amsterdam, Ivy Group has developed two luxury warehouse locations in collaboration with architectural office Rijnboutt and main contractor Van Wijnen. One of these locations features a unique rounded roof structure cladded with rhombus shaped sandwich panels. The structure houses a restaurant.
The roof structure is 80 meters long and consists of a gridshell cladded with 423 rhombus shaped sandwich panels. The term sandwich refers to the layering of each panel, which greatly contributes to the façade’s performance. Because of the semi-circular shape of the roof structure, it is capable of supporting its own weight, thus eliminating the need for supporting columns. This creates a spacious floor plan inside without obstructions of the widespread view over the city of Amsterdam.
In order to assemble the glass into the cassettes without any visible connections, it was decided to employ the benefits of hot bent glazing as opposed to cold bending. The seam between the glass and the sandwich panel is flush with structural silicon sealant. In the design phase Octatube built a mock-up for this, which was also used to determine whether the panels’ play of lines would be consistent on both the inside and the outside. The sheet metal of the cassettes consists of stainless steel on the outside and aluminium on the inside, both finished with a powder coating.
All cassettes are identical in shape, while the size of the glass alternates. Following the architect’s design, the hot bent glass panels in the gridshell structure gradually decrease in size from the bottom upwards. At the top, the sandwich panels do not contain glass at all. In order to install the panels, Octatube created a bespoke aluminium staircase parallel to the structure’s curvature, enabling it to move horizontally.
The assembly of the structure was challenging as the building is situated at one of Amsterdam’s busiest streets, severely limiting the storage space on-site. In order to comply to the strict programme, the prefabricated roof structure and sandwich panels have been delivered and installed ´just in time´. The roof structure was worked out in BIM very precisely by all parties involved.