Image: Sketch of the composite slab - bauwion
In the composite slab, profiled steel sheets are combined with a reinforced concrete layer. Composite means that a joint load-bearing effect of the sheet metal and the reinforced concrete layer above it is achieved. The composite sheet takes over the tensile load in the lower slab area, while the reinforced concrete takes on the majority of the compressive load in the upper slab area. The composite is achieved as a surface or ceiling bond via the geometry of the sheet metal with webs and corrugations, but also via knobs, grooves and rivets in order to avoid displacement of both layers in the event of load. In addition, the composite sheet serves as slab formwork during the concreting process, whereby assembly support is usually necessary.
In practice, composite slabs are often used as pressure belts of composite beams in steel structures. However, it can also be used in solid construction or other types of construction. Since the profiled sheets can be laid by hand and a composite ceiling is lighter than a pure reinforced concrete ceiling, it is also often used in the renovation of old buildings.
According to DIN EN 1994-1-1, a minimum support depth of 75 mm is required for supports on concrete or steel, and at least 100 mm for supports on other materials. Composite ceilings are regulated in Eurocode 4. Since manufacturers manage composite securing very differently, composite ceilings require general building authority approval.
Source: bauwion
