Lateral-torsional Buckling - EC 3


The Lateral-torsional buckling dialog box allows the definition of the lateral-torsional buckling lengths for each flange of the selected steel element. The color code designated for each flange (blue for the upper flange and orange for the lower flange) highlights the corresponding tab and is also displayed in the explanatory picture and in the field corresponding to the calculated value.



How to access the command

Select a steel linear element:


Lateral-torsional buckling

Lateral-torsional Buckling - EC 3




Description of the Lateral-torsional Buckling dialog box


When EC 3 standard is the steelwork standard selected for the current project, the Lateral-torsional buckling dialog box allows the definition of the following parameters:


Recommended values for imperfection factors for lateral torsional buckling curves




Bending moment diagram

Load type



For the lateral buckling verification calculations according to EN 1993-1-1, the procedures for calculating the moment factors Cmy/Cmz/CmLT according to Table B.3 of Annex B include how the bending moment diagram is interpreted and the consideration of sway buckling mode in the element. For the last point the info if the element is braced or unbraced on a given direction is retrieved directly from the steel element properties, from the Buckling group.


LTB Calculations

Braced or unbraced options


These factors determine the interaction factors using Method 2 (used by some National Annexes, including Poland and the Czech Republic).  


You can select the steelwork standard using the Localization settings dialog box. For detailed information, refer to the following section: How to configure the project standards.



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