When applying floor construction techniques comprising lattice girders, the floor is constructed from precast concrete slabs, lattice girders as reinforcement and an in situ concrete overlay.

Precast slabs are reinforced concrete or prestressed concrete slabs which are generally used as permanent formwork for the in situ concrete. After hardening, the slabs in conjunction with the concrete overlay form the floor.

Lattice girders are installed in the precast slabs to ensure sufficient load-bearing capacity and stiffness already during construction and to ensure good bonding between the precast slab and the concrete overlay. A lattice girder is a two- or three-dimensional reinforcing element composed of an upper chord, one or more lower chords and continuous or discrete diagonal bars welded to the chords.

Steel shear heads are used as special punching shear and shear reinforcements to increase the punching shear resistance of point-supported slabs. Steel shear heads are rectangular grate-shaped supports made of structural steels which, as slab-level column head reinforcement, contribute to resisting bending moments and shear forces.

Voided slabs consist of reinforced concrete floor slabs in which void formers are inserted as permanent formwork to create voids in the stab. This leads to reductions in slab weight and material consumption as compared to solid slabs.

Regulatory framework

There are no conclusive technical rules for the design and execution of the construction techniques described above. DIBt therefore grants general construction technique permits (aBG) for these application upon request.

National technical approvals (abZ) can be granted for individual components/reinforcing elements/hollow bodies if they significantly deviate from the applicable Technical Building Rules (cf. MVV TB, Part C) or the harmonised standards.

European Technical Assessments (ETAs) can also be issued for construction products which are not (fully) covered by a harmonised standard.