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RE: Steel Beam Reinforcing

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Randy-

Things to consider:

There are stresses in the existing steel beam. Are you going to shore this
beam relieving the existing stresses before you install the reinforcing
channels? If not, the existing loads are in the existing beam and only the
new, superimposed loads will load the composite section.

Remember that, when you install the reinforcing channels, the channels are
unstressed.

The load distribution between the existing steel beam and new reinforcement
should be proportional to the stiffness.

I believe the methodology for analysis should be something similar to a
composite beam design. The loads on the steel beam when the concrete is wet,
etc.

Some ways I've reinforced steel beams is to weld a flat plate on the bottom
of the bottom flange. I know this requires overhead welding, but usually
exisitng beams in place have difficulty accessing the top flange. Attaching
sections to the web might not change the stiffness of the beam that much.

Good luck,

Bill Allen, S.E. (CA #2607)
ALLEN DESIGNS
Laguna Niguel, CA
http://www.AllenDesigns.com

||-----Original Message-----
||From: Randy Diviney [mailto:rsdiviney(--nospam--at)hayeslarge.com]
||Sent: Wednesday, July 19, 2000 5:47 AM
||To: seaint(--nospam--at)seaint.org
||Subject: Steel Beam Reinforcing
||
||
||I have a few beams in an existing building that will be 40%
||overstressed
||when new loading conditions are applied. I planned on using a channel
||stitch welded to either side of the web to make up the difference in
||required section modulus. The beams have adequate shear
||strength. I noticed
||in our office standards book, we have a chart designed to
||reinforce beams
||with rebar, welded to the top flanges.
||
||My questions are:
||
||1. Am I on the right track using channels?
||
||2. Any better suggestions?
||
||3. Any Internet sites or literature that deals with this?
||
||4. Should I design the channel stitch welding for only the
||moment I expect
||channels to carry
||
||5. Will rebar really work?
||
||TIA
||Randy Diviney
||Structural Engineering Dept.
||Hayes Large Architects
||Altoona, Pa
||(814)946-0451
||
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