"McQualude" wrote in message
...
I found this question in another group (misc.rural)...
Which is stronger, a round post or square post? Assume the posts are
both made from the same wood and are both equivalent in width.
--
McQualude

As another poster indicated, assuming we're talking about bending, the
moment of intertia of a square cross-section is L^4/12. For a circular
cross-section, it's pi*D^4/64. I had to do the calculations three times to
convince myself that this is correct, but all things being equal, a square
post is 70% stronger than a round one when subjected to bending (this is
assuming that the diameter of the round post is equal to the sides of the
square cross-section). Keep in mind that the square has 27% more
cross-section to start with, though. Perhaps a fairer comparison would be
to compare equivalent cross-sectional areas. If equal cross-sectional areas
are assumed, the square cross-section is about 5% stronger.

todd