I was at another site the other day and we had a discussion as to how to reinforce a beam, Barjoist or a tube that is laying in the horizontal position being used as a beam.
The load being a verticle load pushing straight down from the top or being pulled straight down from the bottom.
Wheather the load is a point load or a uniform load.
My question is on an I shape or box shape what is the best way to reinforce this member.
On a beam is it stronger to add steel to the top and bottom flange or is it stronger to add a plate of steel to the webb part of the beam.
Or if the member was a box tube, is it stronger to plate the top and bottom flange or to plate the sides of the tube calling that part the webb.
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Thread: Beam or Bar joist reinforcement.
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02-22-2009, 12:15 PM #1
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Beam or Bar joist reinforcement.
Last edited by Portable Welder; 02-22-2009 at 02:01 PM.
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02-22-2009, 12:45 PM #2
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Not too sure about box tube. I’ve always been told by engineers that an S-shape will fail to one side or the other first, so adding plates to the top and bottom flange will strengthen an S-shape / I-beam.
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02-22-2009, 12:48 PM #3
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Should have added this in the first post!
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02-22-2009, 01:07 PM #4
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Thanks for the picture sonora iron.
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02-22-2009, 01:20 PM #5
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You can strengthen a beam in 2 ways.
1st, you can thicken the flanges as shown above. This increases the strength while not significantly increasing the height.
2nd You can deepen the beam. Sometimes by building a T on top of the area of the greatest stress. This works for point loads mostly.
A taller beam will weigh less than a thicker thinner height beam and support more weight. The key is that you separate the flange by a greater distance. I can't lay my hands on my steel table right now, or I'd give you a good example on how much strength gets added just by increasing the web height vs increasing the flange thickness.
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02-22-2009, 02:29 PM #6
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I don’t think so.
Why will an H-beam / wide flange take more load than an S-shape?
The width of the flanges.
Example: (just a quick look, to find two beams close in size and weight)
24 x 14 x 130# wide flange evenly loaded 15-feet span will take 294,000 pounds.
24 x 7 7/8 x 120# I-beam evenly loaded 15-foot span will take 223,000 pounds.
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