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Re: Question about headed studs on small steel beams

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For my designs, whether noncomposite or composite, I rarely if ever use beams
with flanges less than 1/4" thick (eliminates W8x10, W10x12, etc.).  They just
look so slender in the field to me that I can't see using them except on the
most minor areas.  Also, I don't like the thought of the deck welder welding to
such a thin piece of steel.  That said, the 1/4" flange still does not meet
AISC criteria for composite action if using standard 3/4" studs.  Perhaps the
easiest solution is to eliminate use of anything less than 5/16" flange (W8x15,
W10X17, W12x19 minimum) when considering composite action.  We use RAMSTEEL for
many of our designs.  I eliminated the thin flange beams from the database so
that the program can't choose them.

Eric Ober

Jim Kestner wrote:

> Cliff:
>
> I know we had a problem years ago on some W12x14's where the stud was not
> positioned over the web. I agree with the engineer who said that for small
> beams it is more practical to use non composite.
>
> Perhaps you could have a friendly fabricator do a couple of mockups for you
> to see exactly what happens.
>
> Jim K.
>
> -----Original Message-----
> From:   Cliff Schwinger [SMTP:cliffws(--nospam--at)home.com]
> Sent:   Thursday, February 07, 2002 8:44 PM
> To:     seaint(--nospam--at)seaint.org
> Subject:        Question about headed studs on small steel beams
>
> I have a question about structural steel composite beams.
>
> The AISC spec says that when the flange on a beam is less than the stud
> diameter / 2.5 you have to align the studs over the web.  This means
> that when you use ?" diameter headed studs on composite beams you have
> to get the studs over the web for several of the popular small beam
> sizes (W8x10, W10x12, W12x14 and 16).
>
> Is it realistic to assume that the person shooting the studs through the
> metal deck will be able to align the studs close enough over the web -
> when he can't even see the beam below the metal deck?!  The way I look
> at it - he'll probably figure he did a good job just landing the studs
> anywhere on the flange.
>
> I have been asking this question for several to a lot of people for
> several years now and I have received every answer imaginable. Here are
> some of the answers I have received:
>
> >From a steel erector:  "No problem putting studs on small beams.  We
> snap  a chalk line aligned over the web - the guy shooting the studs
> just puts them on the line."
>
> >From another steel fabricator/erector: "We've never had a problem."
>
> >From a third fabricator: no problem.
>
> >From an engineer:  "We don't design the small shapes as composite
> beams.  We use the small beams as "non-composite" only."
>
> >From another engineer: "Huh?"
>
> >From another engineer:  "We've never had a problem.  We put used headed
> studs on small beams all the time."
>
> Yet another:  "Use smaller diameter studs on the small beams."  (my
> response:  It is not practical having two different stud diameters on
> the floor. This would lead to too much confusion for the person welding
> the studs and we would most likely get a bunch of small studs on beams
> that were supposed to have 3/4" studs. The guys shooting the studs are
> not "rocket scientists" - heck, even a lot of rocket scientists aren't
> "rocket scientists" these days.)
>
> Another opinion: "Studs on small beams?! No way! That's a violation of
> the code dude! Small beams are "unstuddable" Cliff - everyone knows
> that."
>
> Another engineer's "theory": "The thin flange "issue" is only a problem
> when the inspector "inspects" them with his calibrated test apparatus -
> the 10 pound hammer (or is it 15 pounds?).  Hitting them with the hammer
> puts more moment, but less shear on the studs than the stud actually
> "sees" when it is encased in concrete.  When the stud is encased in
> concrete the load on the stud weld is mostly shear and there should be
> no problem."
>
> And finally:  "Sure why not. We just put a note on our drawing telling
> the contractor he has to align the studs over the web.  We been doing it
> for 20 years and have never had a problem.  You're thinking too much
> Cliff."
>
> I know that telling the contractor to align the studs over the web on
> small beams follows the letter of the code; but does it follow the
> spirit of the code?!
>
> Also, has anyone ever heard of a problem occurring due to the
> installation of ?" diameter headed studs on thin-flanged beams?
>
> Thanks for any input.
>
> Perhaps this would be a good research project for someone at a
> University. I'll bet if you contact the Nelson Stud people they would be
> interested!
>
> And yes, I called the Nelson stud people - they didn't have an immediate
> answer. The person I spoke with was going to talk to someone and get
> back to me, but I have not yet heard back from them.  Maybe I'll pester
> them again tomorrow.
>
> Cliff Schwinger
>
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