Lattice girder slabs

Lattice girder slabs act as permanent formwork and as precast soffits for robust, high capacity composite floor slabs. They are cast with most, if not all, of the bottom reinforcement required; the top reinforcement is fixed in situ. The units are typically 50mm to 100mm thick and 1200mm or 2400mm wide.
They are generally propped during construction and until the in situ concrete has gained sufficient strength. Typically spans of up to about 8m can be achieved (for an imposed loading of 5kN/m2) with an overall depth of 300mm. A recent development has been the use of spherical plastic void formers fixed to the lattice girder slab. The resulting composite slab, being voided, has a reduced self-weight and hence increased spans can be achieved. (By The Concrete Society/ UK)