D5.D.10.7 Clause 126.96.36.199 - Slenderness for torsional and torsional-flexural buckling
Equations 6.52 and 6.53 of NBN-EN 1993-1-1:2018 are to be used to calculate the non-dimensional slenderness parameter, λT, to be used for torsional and torsional-flexural buckling checks. The NBN-EN 1993-1-1:2018 does not provide equations to calculate the elastic critical loads Ncr,T,F and Ncr,T (refer 6.3.14 of SS EN 1993-1-1:2005). Therefore, the NCCI document "SN001a-EN-EU: Critical axial load for torsional and flexural torsional buckling modes" provides methods to calculate the Ncr,T,F and Ncr,T factors and hence will to be included in this implementation of the Belgian NA.
The critical axial load for torsional buckling is evaluated as:
The critical axial load for torsional-flexural buckling is evaluated as:
For details on these equations, refer to the NCCI document SN001a-EN-EU.