Strength of non-compact HSS 1

[Imagineer]

What is the formula for reducing the strength of non-compact HSS?

LRFD, pg4-8 gives the formula
phi.b Mn = phi.b Mp - phi.b(Mp-Mr)[(Lb-Lp)/(Lr-Lp)].
But the section says that this is for I or C rolled shapes only.

LRFD, App. F, pg 6-11 gives (substituting l for lambda)
Mn = Cb[Mp - (Mp-Mr)[(l-lp)/(lr-lp)]

Can I use the second formula for any shape?




Imagineer

 

[Imagineer]

Found the answer to my own question in the HSS Connections Manual. The second equation is repeated as eqn 5.1-5. Missed it the first time because I stopped reading at &quot;for lambda<lampda.p ...&quot;

That'll teach me. Read the entire paragraph!



Imagineer