Strong axis plate bending
Strong axis plate bending
(OP)
First off, I rarely design in steel (and haven't really since college), and I'm not all that familiar with the AISC manual. My somewhat hypothetical question is this (and referencing the AISC-ASD 9th Ed, since that is the one I have):
Suppose I have a cantilever steel plate with a point load at the end acting in the strong axis direction. Assume a 100" long beam, 10" deep, and 1" wide. Say a 1-kip load acting at the free end and in the 10" direction. Therefore, a 100 kip-in moment at the base. Using the 9th Ed AISC, what do you check for/against? Compact/noncom/slender of a "web"? There are no flanges, it's not an outstanding leg, and it's not supported along a single edge, right? Fb=0.6*Fy and use Sx of the rectangular section? Fb=0.75*Fy due to additional strength associated with shape factor (but it's not restrained by a flange/web connection)? Is there a specific lateral torsional buckling calculation to be done? It seems that eventhough an allowable Fb may be calculated using 0.6*Fy, that could potentially be limited by some sort of out of plane bucking of the (long)x(tall)x(thin) plate. True or not?
Ideas, opinion, past experience are welcome. Thnx.
Suppose I have a cantilever steel plate with a point load at the end acting in the strong axis direction. Assume a 100" long beam, 10" deep, and 1" wide. Say a 1-kip load acting at the free end and in the 10" direction. Therefore, a 100 kip-in moment at the base. Using the 9th Ed AISC, what do you check for/against? Compact/noncom/slender of a "web"? There are no flanges, it's not an outstanding leg, and it's not supported along a single edge, right? Fb=0.6*Fy and use Sx of the rectangular section? Fb=0.75*Fy due to additional strength associated with shape factor (but it's not restrained by a flange/web connection)? Is there a specific lateral torsional buckling calculation to be done? It seems that eventhough an allowable Fb may be calculated using 0.6*Fy, that could potentially be limited by some sort of out of plane bucking of the (long)x(tall)x(thin) plate. True or not?
Ideas, opinion, past experience are welcome. Thnx.






RE: Strong axis plate bending
The 2005 AISC steel specification is a free download from the AISC. The manual itself is very expensive. You can find the download here. Look in section F11.
AISC 2005 Specification
RE: Strong axis plate bending
I think your question is answered by pointing out that your flanges (non-existent) do not meet the criteria necessary to stiffen the section against LTB.
For particulars, refer to Section 5, article 1.5.1.4 Bending. There is a list of criteria that begin with a requirement that the Flange shall be continuously connected to the web or webs.
As UcfSE pointed out, for this geometry you should check a book on plate buckling. Also, when the D/L gets too large, you start to have effects from shear deformation not normally considered. I recommend Timoshenko, Theory of Buckling, for further information. Good Luck
RE: Strong axis plate bending
DaveAtkins
RE: Strong axis plate bending
RE: Strong axis plate bending
RE: Strong axis plate bending
On a side note, this is a great forum. I've browsed this site for the past 5 years for ideas and opinions, but this was my first time posting a question. Thanks.