Curtailment

Summary

Curtailment - is the reduction of mesh reinforcement in concrete slabs, so that it only covers the area in which it is required. Common in fibre reinforced slabs.

Technical Information

In theory, tension reinforcement is only required in areas where the bending moment imposed on a slab exceeds the moment capacity of the unreinforced concrete. Therefore, it could be considered a waste of steel to provide reinforcement over the whole area of the concrete if the moment capacity of the non mesh reinforced concrete is only exceeded in small areas of the slab. The reinforcement can be curtailed (cut short) where it is not needed. However, it is more common for slabs to be reinforced throughout, with additional reinforcement placed locally where required.
The reinforcement is required to extend a small distance beyond the area in which it is needed to resist moments. This is called the anchorage length, and is usually dependent on the diameter of the reinforcing bars and their effective depth in the slab.

Curtailment is most commonly seen in pile supported slabs where the whole slab is fibre reinforced but extra moment resistance is required above the pile heads.

Curtailment is important for efficient construction of a concrete slab; it can drastically reduce the overall amount of reinforcement used compared to reinforcing the entire area of the slab on both the top and bottom.