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RE: Column Buckling

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You should really call out HSS now a days AND make sure that you use the
section properties from the HSS manual (and I assume the 3rd edition LRFD
manual) but not the 9th edition ASD or 2nd edition LRFD manual.  The
section properties used in the HSS manual better reflect the section
properties of hollow sections (tubes and pipes).  The ASTM (I think) specs
for tubes and pipes allow a tolerance variation of about 10 percent if I
recall correctly.  The manufacturers of tubes and pipes have taken
advantge of tolerance limit to save material as their production
techniques have gotten better.  Then end result is that the "old" section
properties listed in the 9th edition ASD and 2nd edition LRFD (and older)
are less conservative.  The section properties contained the HSS manual
(and I assume the 3rd edition LRFD) manual reflect the use of the lower
limit of the tolerances which result in a more accurate value to section
properties (I, S, r, etc).

So, the result is that you should at a minimum be designing your hollow
sections using the section properties in the HSS manual (which would
technically mean that you are now using HSS shapes...that is how AISC is
"differentiating" the from the "older" section properties).  Beyond that,
you can really call out either on the drawings.  The point is that no
matter what you callout, you are likely getting the hollow sections that
use the lower limit of the tolerance, thus you should be using the more
accurate section properties of the HSS manual for design of ALL hollow
sections.

HTH,

Scott
Ypsilanti, MI


On Thu, 18 Jul 2002, Michael Bryson wrote:

>  
> How many people call out HSS vs. TS ? Is there a difference? Is there any
> reason to call out HSS over TS on the drawings?
> 


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