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Re: sidesway web buckling - AISC 9th edition K1.5

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Ken,

If I recall correctly you have 18" and 16" beams framing in to the 24"
girder.  Some people would consider those deep enough to brace the bottom
flange of the girder with any type of connection (shear tab, single angle,
double angle).  I would say the 18" beams would brace the bottom flange of
the girder if a double angle connection were used or a full height shear
tab (would "double" as a stiffner).  You can do a calc to determine if it
is braced...AISC had seminar done by I beleive Yura that cover things like
adequate bracing of beams.  Typically, to "brace" a flange, only about 2%
of the vertical load must be resisted laterally...if I recall correctly.
Unfortunately, I had to cancel my plans to attend the seminar, so I am not
much help beyond that.

You might be able to get a copy of the lecture material from AISC.

Hope that helps...at least some...

Scott Maxwell, PE, SE


On Fri, 14 Jul 2000, Ken Peoples wrote:

> Bill,
> Maybe I am not reading this correctly, but "l" for
> this section is defined as the "largest laterally
> unbraced length of either flange at the point of
> load".  In my opinion, this bottom flange is not
> braced along its entire 48 foot length.  Am I missing
> something?
> Ken
> 
> 
> --- Bill Polhemus <bpolhem(--nospam--at)swbell.net> wrote:
> > Generally speaking, I would NOT consider that the
> > "stub" column braces the top
> > flange of the GIRDER against lateral-torsional
> > buckling.
> > 
> > BTW, why can you not consider the beams framing into
> > the 24" deep girder as
> > providing bracing? Are they themselves not braced
> > back properly?
> > 
> > Ken Peoples wrote:
> > > 
> > > I am checking for stiffener requirements of a beam
> > > supporting a column.
> > 
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