Fy =36 ksi
Fy =36 ksi
(OP)
Is it conservative to use Fy = 36 ksi when we are not sure about the steel is 36 ksi or 50 ksi?
Thanks
Thanks
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RE: Fy =36 ksi
RE: Fy =36 ksi
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: Fy =36 ksi
RE: Fy =36 ksi
If still in doubt, clip a portion of a beam and have it tested.
Mike McCann, PE, SE (WA)
RE: Fy =36 ksi
offtopic sorry, but,
"clip a portion of a beam and have it tested. ". how big a piece is typically needed, and, who performs such testing and what's range of cost, if you don't mind....
RE: Fy =36 ksi
Mike McCann, PE, SE (WA)
RE: Fy =36 ksi
The owner may have some angles with Fy 36 ksi. I was wondering if I design based on 36 ksi and then they see they don't have enough 36 ksi and purchase 50 ksi will my design based on 36 ksi be conservative or it will be underestimate
Thanks
RE: Fy =36 ksi
Only W shapes are 50 ksi.
As long as the angles are newer than the 1960s or so, I would assume A36. If you are concerned, you can have a piece pulled and tested.
When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.
-R. Buckminster Fuller
RE: Fy =36 ksi
In the basic sense, 50ksi steel is stronger than 36ksi steel, so if the material is one or the other, designing for 36ksi is the conservative option. Stiffness isn't influenced by the yield strength, so long as your structure isn't designed to yield.
Of course, there are a few metallurgical characteristics where 36ksi steel may be better than a 50ksi steel (maybe fracture toughness, or weldability). I'm not a metallurgist, so I don't know specifically for A36 vs A572. But I doubt these affect your small shed.
That said.. do you have a mentor for this project? Seems like you may be having trouble with some fundamentals of structural steel. I'd encourage you to lean on whatever (non-internet based) resources you have.
RE: Fy =36 ksi
RE: Fy =36 ksi
RE: Fy =36 ksi
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: Fy =36 ksi
RE: Fy =36 ksi
Twenty or so beams gained little (less than 5%) from the increased stress grade. Half a dozen actually went down.
Examples:
W200x15 --> Mr = 39.1 kN @ 300 MPa, 39.5 @ 350 MPa
W200x46 --> Mr = 134 kN @ 300 MPa, 139 @ 350 MPa
W250x18 --> Mr = 55.9 kN @ 300 MPa, 55.6 @ 350 MPa
Nothing to rock the world, but the sections in question certainly didn't benefit the way you'd think... The difference from 36ksi to 50ksi is similar, only far more pronounced. Be very careful!
RE: Fy =36 ksi
1) Capacity wouldn't improve because elements would buckle at the lower ksi.
2) Capacity wouldn't decrease because elements could still make it to the lower ksi.
3) Design to the lower ksi would still be safe.
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: Fy =36 ksi
RE: Fy =36 ksi
Cost is about $200 US per specimen here in the southeast US.
RE: Fy =36 ksi
@CEL - 0.3 kN*m seems like a rounding error somewhere. There are four ways a beam can fail - elastic lateral torsional buckling and local flange buckling(F.y has no effect), inelastic LTB and plastic/elastic yield (F.y increases strength)
RE: Fy =36 ksi
RE: Fy =36 ksi
Thank you. I am in Los angeles area.