Repurpose Cambered Steel Beam

[JoshH726]

Working through design of a 48' span assembly loaded (100 psf) non-composite mezzanine beam with 1-1/2" metal deck and 3" nw concrete slab. Contractor has a W30x148 in a yard with a 3/4" camber (W30x99 works). Based on analysis using the W30x148, there is 0.6" of dead load deflection for the beam, so there would be a 0.15" hog remaining. They want to know if they can use it in this application. Structurally, I'm inclined to say yes, and I don't think the contractor is going to be keen on heat straightening the camber out. The floor slab should level itself out.

Anything else to consider here?

 

[dhengr]

JoshH726:
You can barely measure the difference btwn. .6” and .75” of camber in a 48’ long 30” deep WF beam, let alone determine exactly where that occurs over the length. It should not be a concentrated kink, and that camber is certainly well within the mill stds., what about other mill stds. like twist, sweep, flg. squareness, etc? Look at the rusty beam for any heating marks or defects, sand blast and reinspect for defects. What grade of matr’l. is it, do they have mill certs., and will they assume the responsibility for that beam? Will the fabricator accept it and work on it? I would probably allow it, if it was relatively new and I could confirm these other issues. There is always some concern about any added liability that you assume in doing/allowing something like this.

 

[JAE]

A W30x148 - at Fy = 36 ksi - is stronger than a W30x99 at Fy = 50 ksi so mill certs wouldn't be required in my view.

L/360 live load deflection = 1.6 inches.
Not sure what you are worried about with 0.6" "camber".

Technically that isn't really camber as 3/4" is usually the minimum specified camber.



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[SlideRuleEra]

"Camber" of 0.6" on a 48' long beam of that size is within AISC's "Standard Mill Practice" tolerance:

For flange > 6" width, permissible variation in camber (inches) = 1/8 (in) x (total length (feet) / 10) = 0.6 inches

Use it as-is, just turn it "right-way-up".

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