Strengthening of WF Beam
Strengthening of WF Beam
(OP)
I have a 30 ft long girder which is overstressed by 35% (Combined Bending IR of 1.35). I cannot add any supports in between. Only cover plates are the option. But adding one at the bottom is not providing the req capacity. Any ideas will help.
By the way the portion that is deficit in capacity is 14 ft (7 ft on each direction from center)
By the way the portion that is deficit in capacity is 14 ft (7 ft on each direction from center)






RE: Strengthening of WF Beam
Mike McCann, PE, SE (WA)
RE: Strengthening of WF Beam
RE: Strengthening of WF Beam
Mike McCann, PE, SE (WA)
RE: Strengthening of WF Beam
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Strengthening of WF Beam
Mike McCann, PE, SE (WA)
RE: Strengthening of WF Beam
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Strengthening of WF Beam
I was thinking that may be odd retrofit. But looks like its been done
RE: Strengthening of WF Beam
RE: Strengthening of WF Beam
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RE: Strengthening of WF Beam
RE: Strengthening of WF Beam
I will talk to the field if they have access to do welds tot he web. They can access flanges from top and bottom. This is in a very tight space
I appreciate all your time and ideas. This is a great forum
RE: Strengthening of WF Beam
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Strengthening of WF Beam
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: Strengthening of WF Beam
how can you say that is braced to LTB if it can rotate bout wen. Flanges have to be restrained to call it braced to LTB
I am be missing something here, please correct me
RE: Strengthening of WF Beam
RE: Strengthening of WF Beam
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Strengthening of WF Beam
RE: Strengthening of WF Beam
A lot of steel in industrial structures depends on framed beam connections to resist LTB. It works.
www.SlideRuleEra.net
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RE: Strengthening of WF Beam
So I may have to resort to modifications.
RE: Strengthening of WF Beam
The key is to prevent overall section twist. The amount of force and stiffness is provided in AISC's specification - appendix 6 I believe.
You can simply calculate the required strength (twist moment at each brace end) and see very quickly that the shear bolts would usually more than adequately provide the strength.
Yes the bolts may be bearing only but a little slip won't change the fact that the beam is ultimately resisted from twisting.
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RE: Strengthening of WF Beam
Without increasing depth of the WF12, you'd add 4x 12-inch verticals to the outside of the WF, and - you'd add the anti-twist resistance several others have commented on.
The width of the original member is increased, but the connecting beams can be attached to the sides of the TS12x2.
RE: Strengthening of WF Beam
Hey thanks for the reply
the issue we are facing is accessibility to do welds. It looks like they can access from top to weld plate to the bottom flange provided it is wider than the flange.
RE: Strengthening of WF Beam
The ends of the two flanges on a WF shape are sharp, thus you have a "natural" V-shape "weld prep" for a full-penetration weld from the outside of the joint on the WF-TS connection that can be welded with no additional grinding other than clean up to remove mill scale, rust, and surface debris. A substantial stitch weld will be adequate, you will not need a full-length weld.
RE: Strengthening of WF Beam