Andy wrote:

Derek Broughton wrote:

What makes you think that? It's not true. The lateral force is exactly
how these new self-supporting above-ground swimming pools get their
stability. However, the greatest lateral force is at the bottom of that
above-ground section, so maybe it'll work.

But the lateral force works in all directions at the same time, which is
why the swimming pools are stable. The lateral force of water at 1 foot
deep is 0.433 psi. Assuming the frame and joints are secure and can cope
with the low psi then the force in one direction is canceled by the same
force in the opposite direction.

That's the big assumption though - the joints are the least stable part,
especially when working with things like railway ties.

Here I start delving into math I haven't used in 30 years... Assuming a
railway tie is 8' x 8", and you want 2' above-ground (3 ties), then (I
think) the lateral force on the top tie is going to be somewhere around 12
pounds. The force on the one below that is higher, but it's also braced by
the weight of the tie above it. I guess 12 pounds isn't nearly enough to
move a tie, except at glacial speed (and if it's a shorter tie, the force
is correspondingly less), but I still think you want to be really careful
about those joints.
--
derek