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RE: complicated simple connection

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If the canopy is not too large, can the whole thing be fabricated in the 
shop with all welded connections and ship to the site and erected as one 
piece? Even if it needs to come in several pieces can those smaller pieces 
be bolted together using 4" channels back to back at the splice?

Jim K.

-----Original Message-----
From:	Michael Hemstad [SMTP:mlhemstad(--nospam--at)yahoo.com]
Sent:	Tuesday, August 21, 2001 3:53 PM
To:	seaint(--nospam--at)seaint.org
Subject:	complicated simple connection

I am designing a canopy where the architect insists on
using W4x13 members crossing in the same plane.
Unfortunately, the client insists on following the
architect.  Most of the connections can be simple
shear connections, but I'm having a difficult time
coming up with a clean detail.  The reactions are not
high, perhaps 1500 pounds at the most.

I'm considering using a shear tab welded to the
supporting beam, maybe 1/2 inch thick and 2 3/4 inches
wide (the "T" dimension of these beams) with two bolts
into the web of the supported beam.  If I am to avoid
coping the supported beam, the length of the tab will
be about:
   2       half of supporting beam
   1/2     gap
   1 1/2   end distance for bolt
   3       bolt ga. (horizontally)
   1 1/2   end distance for bolt
   -----
   8 1/2 inches.

This is, as I said, not particularly clean.  In fact,
it's really ugly, but it can be erected.  I have
concerns over stability, which is why I'm considering
a 1/2 inch plate.  (If I use this detail, does anyone
have suggestions on how to check the stability?)
Instead of the plate, it could also be done, I
suppose, with a 3x3 angle 8 1/2 inches long, sticking
out of the web of the supporting beam.  This would be
even uglier, but more stable.

Another idea might be to cope the supported beam and
weld a 6 inch long, 2 1/2 inch high plate across its
end, to bolt into the web of the supported beam.
However, I have two lines of supported beams framing
into twelve lines of supporting beams (i.e. 12
double-sided connections on each stringer line), so
fabrication tolerances will catch up to me.  It also
will be somewhat difficult to erect.

The last idea I have is to weld a 3x3 angle, maybe 5
inches long, into the web and under the top flange of
the supporting beam, sticking out about 3 inches.  I
would have what amounts to an erection bolt in the
vertical leg, through the web of the supported beam,
and field weld part of the flange of the supported
beam to the horizontal of the angle.  The toe of the
angle would need to be ground to fit the fillet of the
supported beam.

A lot of ideas, none of them great.  I wouldn't care
so much except I've got a lot of this type of
connection on this canopy, and maybe 6 more similar
canopies  to come.  If anybody has any better ideas,
please let me know.  Thanks in advance.

Mike Hemstad, P.E.
TKDA
St. Paul, Minnesota

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