Basic Tutorial about buckling lengths in SCIA Engineer 19.1 

yes, maybe. I don't have so much experience, and didn't found some rules how to select the buckling shape. Maybe, because of the bending moment shape, it would better fit to use the clear buckling around weak axis.

​@@IvanBeles I just meant that you missed to change the buckling mode for weak axis (time 36:18). Once again, tutorial is great.

First, this should answer some professor from University. I think, the buckling shape should be affine to the deformation from the combination in the static analysis. Important is, to have the members under pressure, and best way with constant axial force. I try to get all columns to lose stability at the same or near level of load. Lateral forces are not important, because the stiffness matrix will be weaker due to the negative axial force. Sometimes, if I have to find only the buckling length, I define a special load case with ľ forces on the member. One from left one from right. Then the first buckling shape is the buckling around the weak axis. Because sometimes you have structures, where the important buckling shape is after 50.th or later. For the evaluation of buckling length, I think, the level of the load is not so much important, because the buckling length will be calculated from Ncr. And this is N * Lambda. If you use a smaller "N", you will get higher Lambda, and vice versa.

For this example I used the characteristic load to determine the "Lambda". So, if you use the design load it will be less than 16. But in the check itself, SCIA Engineer checks the ratio between N.crit and NEd. And if it is not necessary, the buckling check will be not performed.

Yes I understand is not necessary the stability analysis. In this example (ok with characteristics loads) you have Ncr=16N. If you put all uls combination maybe have smaller lamda. But if you do stability analysis and have lamda bigger 10 then you have non sway type of construction and “k”

Maybe you are right. I don't know about such rules in Eurocode. But this discussion is more for professors from universities. The goal of this video was to show how SCIA Engineer works and give this information to customers.

@@georgechrisopoulos540 According to Eurocode3, you need to calculate a certain factor alpha_cr and check if it is bigger or lower than 10. If alpha_cr >= 10, the structure is non-sway. If alpha_cr < 10, the structure is sway. If I am not mistaken.

@@IvanBeles Maybe it would be nice to have a tutorial on how to check if a structure is sway or non-sway. This has indeed a big impact on the buckling factor and so also on the dimensioning of the columns.