On Wednesday, April 29, 2015 at 1:18:02 PM UTC-7, Russ wrote:
11ga would probably be thick enough.
Euler buckling, if you want to do are real analysis.
Figure between 3x and 10x the wood you are replacing. But you have little in the way of dampening for straight lengths, where wood will internally dampen vibrations. May need some light x-bracing, say 1.5 x 1.5 inch to within a foot or so of each end.
Should last until about the end of time, or until you forget to put drain holes near the bottom to let water (condensation, rainfall, spilled beer) flow out easily.
I am not a structural PE in any state.
David A. Smith
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