Hybrid Concrete Structures

Hybrid concrete applies the same logic as hybrid steel to reinforced concrete: the vertical structure in one material, the roof in another.

Concrete columns are strong in compression and vertical load. Where they are weak is span — a wide-span concrete roof is both heavy and slow, extending the programme with formwork and curing time. A steel superstructure solves both at once: being light, it reduces the load on the columns; being factory-made, it shortens time on site.

The point where the system works is the column head. The steel structure is fixed to the concrete with purpose-designed anchorages; the connection detail is calculated for the differing behaviour of the two materials — the rigidity of concrete and the deflection of steel.

There is a second application: a facility whose concrete columns are still standing can move to this system when its roof is renewed.