CSA s16-14 (Canadian Code) Single Angle under flexural torsional buckling 1

[Bridge_Man]

Hi,

Am an AISC user not used to the CSA codes that much, and I want to calculate the compression resistance of an angle using CSA S16-14 13.3

I have no problem calculating flexural buckling but when it comes to checking the flexural torsional buckling I have two problems:

1- when you look at the AISC criteria for flexural torsional buckling (E.4) , we only have to check single angles for flexural torsional buckling only if b/t > 0.71 Sqrt(E/Fy) . is there such a a criteria in CSA code ? I haven't seen any although the equation is exactly the same.

2- when you check the handbook steel construction (canadian code) example provided for the single angle in part 4 they only check the flexual buckling but they don't even mention the flexural torsional buckling. what is the reason behind that ?

Thanks in advance

 

[ClearCalcs]

For most cases, Cl 13.3.3 lets you consider only flexural buckling by using their provided formulas for effective slenderness KL/r. This depends on your "nominal" slenderness and the ratio in leg length for unequal angles. In cases where your end connections induce additional eccentricity, or if your unequal legs are very different in length, you need to directly consider torsional buckling.

For angles subject to local buckling (b/t < 250/sqrt(Fy) per Table 1), Cl 13.3.5 deals with these, where you reduce your effective cross-section size. They explicitly mention calculating your elastic buckling stress using Cl 13.3.3, so you don't need to consider torsional effects as long as you still meet the original criteria.

-Laurent

http://www.clearcalcs.com

 

[Bridge_Man]

Clearcalcs,

Dude, you are awesome. very clear and makes perfect sense.

Thank you so much. I might have a future question about WTs hopefully you see that one too.

Much appreciated.