Punching Shear Reinforcement

The weight of a slab supported on a column induces shear stresses in the slab. These stresses, if sufficient and where additional reinforcement is not provided, would result in the column ‘punching’ through the slab. This punching shear is similarly induced in the footing on which the column bears.

Although punching shear can be relieved by localised thickening of the concrete with downstand beams and enlarged column heads, the construction of flat slabs offers many advantages. A consistent head space can reduce the overall height of a building and provide significant time and material savings.

Ancon Shearfix

This is a shear stud rail system, sometimes called SSR on drawings.

Used within a slab to provide additional reinforcement around columns, Ancon Shearfix is the ideal solution to the design and construction problems associated with punching shear.

The system consists of double-headed studs welded to flat rails, positioned around the column head or base. The shear load from the slab is transferred through the studs into the column. The studs are welded to the rail at centres determined by Leviat’s software or by a design calculation.

Shearfix is suitable for all column shapes and is easy to install either ‘top down’ or ‘bottom up’, depending on user preference.