ASD 1989 vs 2005 Slender Compression Elements

[ToadJones]

Anyone have any advice on the nightmarish task of determining allowable stresses per the 1989 AISC Code (Green Book) Appendix B.
This appears to be a iterative proceed of monumental proportions.

The Black book seems a bit simpler as it says you can use "Fy" in lieu of "f".
Can this same simplification can be made for the Green Book?

 

[JoshPlumSE]

One or two iterations will likely be enough to converge on an f value. Though it is certainly a pain.

In practice, I have sometimes assumed that f is equal 0.6*Fy. I thought that I had originally gotten that assumption from the commentary. But, am having trouble finding it.

I may have gotten from the SSRC guide, or (more likely) I may have just decided to use 0.6*Fy because that represents an upper bound on that stress value. The commentary does say that this assumption can be unnecessarily conservative.

 

[ToadJones]

Josh-
There is no commentary on App. B is there?

 

[delagina]

it says see commentary chap B for the discussion of slender compression element

 

[JoshPlumSE]

Yes, the commentary for Appendix B is actually all contained in the chapter B commentary. That's what I was referring to.

 

[ToadJones]

Josh-
I can't tell from reading the commentary if it is permissible to use 0.6FY for "f"....do you know if it is?

 

[JoshPlumSE]

Since the commentary refers to that assumption as being unnecessarily conservative, I'll go out on a limb and say that it is allowed..... As long as you're willing to accept overly conservative answers.