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Welding Tubes

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I am trying to develop the full strength (actually close to the full
strength - 25.5 ksi)  of a ts14x6x1/4 (Fy=46 ksi) welded  onto another
tubesteel.  The support tube steel contains internal stiffeners to address
the deformation of the top flange.

My problem is weld size.  I would prefer to do this with a simple fillet

to simplify the calculation:

1/4" (tube wall size)x25.5 ksi = 6.375 kip/inch
6.3752 kip/inch / 21 ksi (E70 electrode)=.30357"
.30357/.707 = 7/16"
and I would prefer some extra so 1/2"

  We have other methods (more intricate) available to make this connection,
but I would prefer to keep it simple.

1.  Is this size weld permissible on a 1/4" wall thickness?

2.  Is using a different electrode an option - our fabricator informed us
that there is a chemistry problem with using an e80 or other electrode.  I'm
really not familiar with the use of electrodes other than e70.  AISC seems
to simplify it and does not address any issues of chemistry.  Does this
sound correct?

3. Another option is a full penetration butt weld (probably difficult to
back, but possible) for which the AISC allows the full strength of the
material joined to be used.  How is this achieved vs. the fillet weld which
is limited by the electrode?

I'm using the ASD AISC.  The answer may be in the Tube steel connection
design Manual, but someone swiped it from our office (and I think he's in
Russia right now)

Thank in advance,


Rich Kipke, PE
> Structural Engineer
> Haden inc.
> 1399 Pacific Drive
> Auburn Hills MI 48326
> direct:(248)-475-5144 Fax: (248)-475-5227
> RKipke(--nospam--at)