Allowable Compression Stress For A Rectangular Plate Column.
Allowable Compression Stress For A Rectangular Plate Column.
(OP)
I have a 3/8" x 7 1/2" x 1'-2" plate subjected to compression. When I look at Chapter E & Appendix B of the 9th Edition of the Steel Manual, it seems that all the provisions apply to elements supported on at least one edge such as stems of tees and beam flanges.
What I have is a solid column. It is loaded over the 7 1/2" x 1/4" area on the two ends of the plate but there is no support parallel to its 14", length.
What do I use as an allowable stress?
What I have is a solid column. It is loaded over the 7 1/2" x 1/4" area on the two ends of the plate but there is no support parallel to its 14", length.
What do I use as an allowable stress?






RE: Allowable Compression Stress For A Rectangular Plate Column.
I am coming up with 8.93 ksi (assuming a 36 ksi plate)
RE: Allowable Compression Stress For A Rectangular Plate Column.
RE: Allowable Compression Stress For A Rectangular Plate Column.
Pin-pin is correct if the two loaded ends are free to rotate, but are restrained against displacement. Does this describe your case? For all we know from the description, it could be rotationally fixed on one end and free on the other, so K=2 and KL/r=258.
csd, not sure how web crippling or even local buckling applies. I think it's just a lateral buckling problem.
RE: Allowable Compression Stress For A Rectangular Plate Column.
RE: Allowable Compression Stress For A Rectangular Plate Column.
A consultant I am working with asked me how my plate complied with table B5.1. I think the answer is that it complies with table B5.1 because it has no outstanding elements that can buckle locally before the full compression strength of the section is achieved. It complies with Table B5.1 because it does not have any outstanding flanges or stems and because it is a solid shape.
271828 is correct the final design of the plate depends on the K value. However determining the K value is another topic entierly.
RE: Allowable Compression Stress For A Rectangular Plate Column.
Also, while it may not have any outstanding elements to buckle locally, the entire plate may still buckle. That is what equation E2-1 and E2-2 are for.
I looked pretty closely at table B5.1 and I am not sure I see anything in there that I would say this plate qualifies as. Maybe it could be classified as a "flange cover plate between lines of fasteners" and use the 7 1/2" dimension as the distance between lines of fasteners, b.
Does anyone else have a different opinion?
RE: Allowable Compression Stress For A Rectangular Plate Column.
RE: Allowable Compression Stress For A Rectangular Plate Column.
RE: Allowable Compression Stress For A Rectangular Plate Column.
RE: Allowable Compression Stress For A Rectangular Plate Column.
Think of it as if it *was* a local buckling problem. What would the buckling mode look like? You guessed it, the entire plate buckling in a lateral buckling mode which sends you to Chapter E.
There are higher buckling modes that look more like some of the mode shapes used in Table B5.1 derivations, but these buckling loads would be much higher so are of no interest.