# Calculation of deflections: the shrinkage curvature 1/`r`_{cs}

_{cs}

## Eurocode 2 part 1-1: Design of concrete structures 7.4.3 (6)

The shrinkage curvature may be calculated as follows:

1/r = _{cs}ε _{cs}α (_{e}S/I) | (7.21) |

where:

- 1/
`r`_{cs} - is the curvature due to shrinkage
`ε`_{cs}- is the free shrinkage strain
`S`- is the first moment of area of the reinforcement about the centroid of the section
`I`- is the second moment of area of the section
`α`_{e}- is the effective modular ratio

`α`=_{e}`E`/_{s}`E`_{c,eff}with:

`E`_{s}- the design value of the modulus of elasticity of the reinforcing steel, see § 3.2.7 (4)
`E`_{c,eff}- the effective modulus of elasticity for concrete.

`S` and `I` should be calculated for the uncracked condition and the fully cracked condition, the final curvature being estimated by the application 7.4.3 (3).

This application calculates
the shrinkage curvature 1/`r _{cs}`
from your inputs.