Single angle bracing design in compression

[Hanuman005]

Hi,

While designing single angle bracing member in compression, I came across two approaches as per TIA-222-G standard.
One approach is similar to AISC where slenderness is calculated for table 4.4 of TIA-222-G(which includes eccentricity between CG of angle and connecting gusset plate)
KL / r = 60 + 0.50 L / r ----------------Normal framing eccentricity at both ends
What length should I consider for calculating KL/r, when restraint is provided in one direction as shown in attachment? should it be full length or half length of brace?

the second approach which is conventional method from table 4.7 of TIA-222-G standard
where In plane length is considered as half with radius of gyration as minimum. and out of plane length considered as full length with radius of gyration of respective geometric axis.
But in this case eccentricity between CG of angle and connecting gusset plate is missing.

Which approach shall I use for design of brace in compression?

 

[r13]

Use L/2 for in plane actions, and L for out of plane actions.

 

[cristiano.ronaldo]

use L which is safer.

 

[MIStructE_IRE]

What about the out of plane? I’d take L out of plane and L/2 in plane.

 

[r13]

cristiano is correct. I made mental mistake. The unbraced plane governs the allowable compressive stress, so use full length L to calculate slenderness ratio.

 

[Mohanlal0488]

I normally would use L/2 when in compression and L for tension for the type of arrangement presented.