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RE: Steel: Moment Connections

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As wonderful as all the analysis I learned in school was, I never quite
believe in the expected real values, factored or unfactored.  In my humble
opinion, the only forces that should be considered at the connection of a
moment frame are those that result from beam reaching it's plastic moment
capacity (or 125% of it!!)

I'll run a SAP model to get forces to frames and size beams and columns for
drift, then throw that analysis in the trash when it comes to detailing the
connections, opting for simpler static's.  After researching with various
steel mills, my office came up with a yield strength of 58 ksi for A36
steel, as that's what suppliers told us we would get (yeah, not 60 but 58,
go figure).  We use that when finding the plastic strength of the beam.  For
narrower frames, we'll back off a little on the plastic approach, and design
for shear based on our forces from the analysis with an appropriate Rw
factor, usually less than 1.

While we're on the subject of moment frame connections....

Haunch or Dog-Bone?  Any arguments for either?  I'm partial to the haunch
myself, as the beam seat will take care of the shear and the bolts really
become erection bolts not needed structurally.  Of course, architects hate
it and I cannot really blame them.


-----Original Message-----
From: Stan J [mailto:hawneng(--nospam--at)]
Sent: Wednesday, June 24, 1998 8:03 PM
To: seaoc(--nospam--at)
Subject: Re: Steel: Moment Connections

Since our allowable loads have been factored down
from expected real values, it may be that, in
order to prevent a great deal of slippage in the
connection, one would need to back out this factor
for the design of the slip critical bolts.