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Re: Rolled Wide Flange Beams to Trolley Around Corners

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Ed,

I have had some experience with bending shapes, although the material was
aluminum. I had the same concerns and found the following:

Cold working did in fact increase the yield and ultimate strengths however
there was a loss of elasticity associated with it. I did not consider this a
problem as the actual stress that i allowed in my design was kept relatively
moderate.

I did have one problem, however, with fabrication. In spite of the
fabricators claims, and published material, regarding the size of members
and radii that they could bend them to, they butchered the shapes in the
process.

It appeared to me that the rate of bending had an effect on the actual
outcome. In one instance the fabricator bent the shape (channel section,
bent about the weak axis) so fast that the tension edge of the flange
developed transverse cracks. This fabricator, and his process, were
immediately dismissed.


good Luck

DPE

At 03:42 PM 10/6/1999 -0500, you wrote:
>
>I have completed step 1, found a machine shop to roll a wide flange beam
>with a 3 to 4' radius.  Step 2 is to figure out what's left of the beam
>afterward.  The point here is to allow a trolley to roll around a corner in
>a plant.
>
>The machine shop cold rolls the beams, and claim they can do it without the
>flanges buckling.  We only have to support about 5.5 kips, and we can
>shorten the span to just about anything.  I would think that the beam would
>become stronger from cold-working.  Lateral stability, I would think,
>wouldn't be an issue if the beam is supported in the center of the bend.
>Local buckling of the inside flange, that I would think would be a little
>wavy from the process, seems to be the bugger.
>
>Am I on the right track here (no pun intended)?  Is there some kind of
>standard practice someone could clue me in on?
>
>Thanks.
>
>Ed Fasula, E.I.T.
>
>
>
>
David P. Evangelista, P.E.
Evan Corporation
8 Reise Road
Jamestown, RI 02835

401.423.2230 Phn
401.423.2785 Fax
dpe(--nospam--at)evancorp.com