Single angles structures design

[DomDunk]

Dear,

Good Morning. I would like to share with you some reflections regarding the calculation of truss box conformed by single angles. I am using the AISC 360-16 standard. As I understand it, I have two ways to check angles.

1) Neglecting the eccentricity of the axial load in the angles (axial axis - connection position)
The slenderness is increased according to the equations (E5-3) or (E5-4).

2) Taking into account the eccentricity of the axial load in the angles (axial axis - connection position)
The angle is verified with respect to its main axes (w, z) as shown in example E.14 ("Design examples").
slenderness = Lc / rz
Do you model the offset of all the angles of the box truss?

Both in the first case and in the second, the slenderness that is obtained is very high. To respect L / r <= 200 you have to use big profiles. That makes me think that box trusses with angles are not the optimal option.

How do you calculate structures with angle profiles? In your opinion, what is the best way to calculate them?

Thanks,

Daniel

 

[TLHS]

What's your geometry? In typical truss application I wouldn't be expecting a slenderness ratio cutoff failure for web members with reasonably constructible sizes. For the chords it wouldn't be unusual to need bracing, but if it's a space frame (truss box), I would expect that the bracing would be an inherent part of the system and once again wouldn't be a problem.