Specialist know-how: Folded Plate Floor Slabs in Prestressed Concrete
The load-bearing structure of the Namics office building in St. Gallen, Switzerland, is constructed almost entirely of reinforced and prestressed concrete. Relatively thin concrete floor slabs span transversely as folded plates across the entire width of the building, allowing the open spaces below them to be uninterrupted by intermediate vertical supports. Flat slabs are preferred for the circulation cores at each end of the building and for the whole of level -2. At the top of the building, level +4, the roof is supported by a longitudinal steel hollow box girder with simple, lightweight steel framed ribs cantilevering on each side. The building’s overall structural system consists of a pair of transverse walls at each circulation core and the frames of the two longitudinal facades. The whole structure rests on a slab foundation, which is thickened locally under the most heavily loaded walls. The transverse walls and facade frames together with the slabs, which act as diaphragms, provide the resistance to horizontal forces.
