The steel decking has two main structural functions

The steel decking plays a very important role in the structure, has two main structural functions:

Formwork function

During concreting, the steel form decking supports the weight of the wet concrete and reinforcement, together with the temporary loads associated with the construction process. It is normally intended to be used without temporary propping.This kind of steel decking, we call it steel form decking.

Composite floor slab function

In service, the steel floor decking acts ‘compositely’ with the concrete to support the loads on the floor. Composite action is obtained by shear bond and mechanical interlock between the concrete and the decking. This is achieved by the embossments rolled into the decking – similar to the deformations formed in rebar used in a reinforced concrete slab – and by any re-entrant parts in the deck profile (which prevent separation of the deck and the concrete).This kind of steel decking, we call it steel floor decking.

The steel decking may also be used to stabilize the beams against lateral torsional buckling during construction, and to stabilize the building as a whole by acting as a diaphragm to transfer wind loads to the walls and columns (where it is designed to do so, and in particular where there are adequate fixings. The decking, together with either welded fabric reinforcement placed in the top of the composite floor slab or steel/synthetic  throughout the slab , also helps to control cracking of the concrete caused by shrinkage effects.