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Question about headed studs on small steel beams

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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 ¾" 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 ¾" 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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