Calculation of nominal curvature
The curvature for calculation of second order eccentricity is calculated according to clause 5.8.8.3 in EN 1992-1-1.
(1/r)y(z) = Kr ∙ Kφ,y(z) ∙ (1/r0)y(z)
where
| Kr |
is a correction factor depending on axial load, see clause 5.8.8.3 (3) in EN 1992-1-1. This factor depends on relative normal force (n), see "Relative normal force" and mechanical ratio of reinforcement (ω), see "Mechanical ratio of reinforcement - check" or "Mechanical ratio of reinforcement - design". The formula below can be used for symmetrical cross-section and symmetrical reinforcement. For unsymmetrical cross-section and reinforcement the simplification according to [4] is used value Kr = 1 Kr = (1 + ω - n) / (1 + ω - 0,4) |
| Kφ,y(z) |
is factor for taking into account of creep around y(z) axis of LCS , see clause 5.8.8.3 (4) in EN 1992-1-1. This factor depends on effective creep ratio (φef), see "Effective creep ratio" and factor (βy(z)), see "Coefficient beta" depending on slenderness Kφ,y(z) = 1 + βy(z) ∙ φef ≥ 1 |
| (1/r0)y(z) | is the basic value of curvature around y(z) axis of LCS, see "Basic value of curvature" |