# Longitudinal reinforcement for pure torsional moment, Σ`A`_{sl}

_{sl}

## Eurocode 2 part 1-1: Design of concrete structures 6.3.2 (3)

The required cross-sectional area of the longitudinal reinforcement for torsion Σ`A _{sl}` may be calculated from:

(ΣA⋅_{sl}f) /_{yd}u = (_{k}T⋅cot_{Ed}θ) /(2 A) _{k} | (6.28) |

where:

`T`_{Ed}- is the applied design torsion
`A`_{k}- is the area enclosed by the centre-lines of the connecting walls, including inner hollow areas (Figure 6.11)
`u`_{k}- is the perimeter of the area
`A`_{k} `f`_{yd}- is the design yield stress of the longitudinal reinforcement,
`f`=_{yd}`f`/_{yk}`γ`,_{S}

see § 2.4.2.4 (1), § 2.4.2.4 (2) for the values of`γ`,_{S}

see § 3.2.2 (3)P for the uper limit of`f`,_{yk}

see Figure 3.8 for the design stress-strain diagrams of the reinforcing steel. `θ`- is the angle of compression struts, see Figure 6.5 and § 6.2.3 (2).

This application calculates
the longitudinal reinforcement for torsion Σ`A _{sl}`
from your inputs.