A collaborative slab or collaborative sheet metal slab is a type of mixed slab composed of a corrugated steel sheet profile and a concrete compression layer, in which the sheet itself fulfills a resistant function as positive reinforcement and not only as lost formwork, so both materials collaborate structurally. The system is usually completed with a distribution mesh embedded in the concrete, in order to avoid cracking due to shrinkage and temperature changes.

In order for both materials to work in a supportive manner, the sheet metal must be specifically designed for this purpose, for which it usually has projections or embossings that facilitate the transmission of stresses between one material and another and prevent relative sliding between the two.

In 1950, in the USA, the first patent for this type of forging was made. The connection between both materials was made by means of steel plates arranged transversely and welded to the crest of the corrugated sheet; These are later replaced by a welded mesh also on the upper part of the sheet. Later research developed new shapes to guarantee the perfect connection between both materials (overcoming the shear stress), introducing embossings or indentations on the lateral faces.

In Europe, the introduction of collaborative slabs dates back to the late 1960s. Research to solve the main problem of composite slabs, the shear stress, continued to develop and around the mid-eighties the American Society of Civil Engineers published “Specifications for the Design and Construction of Composite Slabs”. At the same time, the British Standard BS-5950-82 is published. Both have been and continue to be a reference for this type of system.

As collaborative slabs are considered non-traditional constructions, French researchers in their publications of the “Avis Techniques” guidelines consider carrying out an in-service analysis in addition to the corresponding failure analysis. These guidelines are the first reference to the current Eurocodes that are still being modified today.

A composite composite sheet slab is made up of a corrugated steel sheet profile on which a layer of concrete is poured. The materials are arranged in such a way that when the slab comes into service, the lower steel sheet resists tensile stresses, while the upper layer of concrete resists compressive stresses, so both materials work optimally. It is common to complete the system with a corrugated steel distribution mesh, in order to avoid cracking of the concrete due to the shrinkage it experiences during the setting process.