Clause 6.3.2.2 – Lateral torsional buckling curves - general

The D-NA states that the values for the imperfection factor, α_LT, to be used in equation 6.56 of EC-3 are to be obtained from Table 6.3 of EC-3. These are the values used by STAAD.Pro.

Clause 6.3.2.3 – Lateral torsional buckling curves for rolled sections or equivalent welded sections

The D-NA states that:

1. The values for the:

   • Imperfection factor αLT0 = 0.4 (used in equation 6.57 of EC-3)
   • Β = 0.75 (used in equation 6.57 of EC-3)

   These are the default values used by the program.

2. The buckling curves shall be selected as per Table 6.5.

3. The reduction factor, f, is given by:

   f = 1 – 0.5(1 - kc)[1 - 2x (λLT -0.8)2].

   where

   kc

   =

   a correction factor for moment distribution determined from Table 6.6. This value can be specified or calculated by the program using the KC parameter. Refer to D5.A.6 設計パラメータ

   STAAD.Pro conservatively uses a value of f = 1.0.