D5.B.3.7 Clauses 6.3.2.2 and 6.3.2.3 – Lateral torsional buckling curves
Clause 6.3.2.2 – Lateral torsional buckling curves - general
The D-NA states that the values for the imperfection factor, αLT, 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:
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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.
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The buckling curves shall be selected as per Table 6.5.
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The reduction factor, f, is given by:
wheref = 1 – 0.5(1 - kc)[1 - 2x (λLT -0.8)2]. - 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.