Compact, non compact section properties as per AISC 2005

[SEMCM]

I have one query regarding AISC 2005
Recently I checked whether my I section is compact, non compact or slender
As per Table B4.1 I got my flange as non compact and my web as slender
But how come my section is passing in staad if it is a slender section
My section sizes are 1400x10 web and 350x14 flange
Can anyone help me with this
Or am I missing something?

 

[SALTRAM4567777]

Why do you think a slender section cannot be designed.

 

[271828]

The next question is whether STAAD correctly handled a section with slender elements. The default assumption is it does not. Verify before relying on its results.

 

[SEMCM]

Why do you think a slender section cannot be designed.

The next question is whether STAAD correctly handled a section with slender elements. The default assumption is it does not. Verify before relying on its results.

But according to plate limitations 1400/10 = 140 is not exceeding the limit right?
(H/tw= 180 ) Please correct me if I'm wrong

 

[JoshPlumSE]

I think you need to do the calculation manually to verify if STAAD is doing it correctly. Some comments:
a) The slenderness limits usually have some relationship to the yield stress. Not just to the dimensions of the section alone.
b) The section properties in STAAD may not be the same as you do by hand.... Is the H value the clear depth of the web from flange to flange. The total dept of the member or the depth between flange fillets.

 

[BulbTheBuilder]

The slenderness in Chapter B isn't the same as that in Chapter D and E for tension and compression slenderness ratio. Chapter B is slenderness per geometric properties (that the beam can develop full plastic capacity before buckling locally) whilst chapter D and E kind of considers it globally (with reference to length).

Say a member is compact per Chapter B, we know we can achieve plastic (full yield stress) before buckling occurs - max capacity.
If a member is non-compact / slender, that member doesn't achieve plastic (some minor yielding) and the beam fails.

The strength of non-compact section = min of (lateral torsional buckling [LTB], flange local buckling [FLB], web local buckling [WLB]). I don't think STAAD can do FLB and WLB, you'd have to do that manual. refer to AISC Example manual for sample calcs