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Flange buckling

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I assume we are talking about a flange that belongs to an I-beam, or a wide-flange beam.
Probably you have one flange well-supported, but the other one can buckle.
There are several possible modes depending on proportions and constraints.
One practical way is to build a little FEA model and run buckling.
There are at least two different ways I can think of to stiffen the flange.
One would be to make a set of triangles, one side of the same length as the width half-flange.
Then weld those in to connect web and flange alternating web sides as you go along.
Keep the distance between the succesive triangles close to the width half-flange.
The other way is to cut two long strips and attach them to the tip of flange,
on both sides of the web, at right angles to the flange. Height of each strip
should be half the width of half-flange.
Hope this helps a little.
Gregory from Oz

Subject: Seismically Non-Compact Beam
From: "Steiner, Matthew" <MSteiner(--nospam--at)>
To: <seaint(--nospam--at)>

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We are evaluating an existing SMF building that has a number of beams
that are seismically non-compact because of the flange width to
thickness (Actual is 7.67, Maximum is 7.23).


I was thinking of adding web stiffener plates to stiffen the flanges and
prevent buckling but I'm not sure how to determine the buckling length.
My guess is there is some variation of plate theory that can be used to
find the local flange buckling length and use that to determine the
spacing of the stiffener plates.


Any references are appreciated.