Driving from Osnabruck to Hannover, past the town of Melle, a gigantic flame-shaped building towers above the horizon. This is the new innovation centre of stove manufacturer Spartherm. Referring to Spartherm's specialism, the building - designed by Podufal Wiehofsky - has been given the distinct shape and colour of a stove flame. Octatube developed and built the entire facade with one important condition: it had to be as transparent as possible. This project was a unique opportunity for us to use our expertise in the cold bending of glass on a scale (and at a considerable height) we had not done before.
Innovationzentrum Spartherm is 40 metres high and consists of over 6500 m2 of glass, with glass panels measuring 5.5 x 2.6 metres. Because of the gradient radius of the facade, many of the glass panels have a different radius. We chose to cold bend a large part of the glass in the work, needing less unique glass panels. And in addition, the transport of flat panels is more efficient.
Unique glass vacuum lifter
Together with Viavac, we have developed a special vacuum lifter to handle the large glass panels. The uniqueness of this vacuum lifter is not only that it can pick up such large panels, but also that it can rotate these panels 90 degrees and bend them to the desired angle. As we work at a considerable height of 40 metres, this is a remarkable achievement. The device, which is remote controlled, has to perform a great many manoeuvres in the air. Once the glass panels are bent in place, they are secured on the outside with pressure plates. These are then covered with snap-on profiles.
Concrete, glass, wood, aluminum
The building consists of a concrete construction. We placed steel uprights and beams on top of which we then mounted the glass. In the ridge of the roof, the curved structure is formed by laminated wooden trusses, produced by the German company Schütt. On top of this wooden structure we pulled a steel structure, then the glass. It is insulating glass, laminated outside and inside, heat strengthened. Where the glass serves as cladding (there is concrete behind it), it is virtually black and fritted (12mm fully tempered). We also cold bended the large fritted panels. The small panels of the curved facade are too small to be cold bent. These panels were therefore delivered hot bent on site and then put in place. The facades are capped with yellow aluminum cladding.
Prefab and assembly
To ensure that assembly runs smoothly and quickly, we prepared as much as possible in our factory. The steel and wood construction and the accompanying steel brackets, but also all connections for the long facades are prefabricated in our factory as well. We limited damage and the quality remains high. This preparation also means that we were on site as short as possible.
In order to be able to mount from the outside in the ridge of the roof, we worked on an assembly bridge. The bridge runs over the ridge of the building at a height of 40m and it runs over a rail at a height of 25m along the building. From there the fitters can assemble.
In Germany, you have to ask permission for any non-standard application. For the facades of the Innovationzentrum, we have used various new techniques and have therefore applied for different permissions. We have made it plausible that the techniques used are safe. For example, the use of a glass facade as fall-through safety is not included in the standards in Germany. In addition, cold bending of the glass is not common either. For these techniques, we have obtained specific approval for this project by means of technical substantiation and structural calculations.
Octatube now has extensive experience with cold bending of glass. But the size of the glass panels made it an interesting challenge for us. Together with the yellow aluminum edge, the transparent glass Innovationzentrum forms a striking marker in the otherwise flat green landscape of Melle and its surroundings.