The Polish-NA provides the values for the terms λ_LT,0 and β factors given in clause 6.3.2.3(1) as follows:

For all sections, use:

• λ_LT,0 =0.4 and β = 0.75

The Polish NA specifies the use of uses table 6.5 to work out the buckling curves for use in Cl. 6.3.2.3. Hence table 6.5 in PN-EN 1993-1-1 will be used for this.

These equations and factors are then applied to equation 6.57 of PN-EN 1993-1-1 to evaluate the Lateral Torsional Buckling reduction factor χ_LT.