From: Roger Turk <73527.1356(--nospam--at)compuserve.com>
Date: Wed, 10 May 2000 10:46:24 -0400
I always recommend that a person contact a swimming pool company for a
residential pool and explain that the pool company can amortize the
engineering cost over many pools, but the engineering cost for one pool has
to be borne by the owner. If a pool has a "free-edge," or is bordered with
a retaining wall, I will design a retaining wall for the pool, consider the
soil behind the wall fully saturated, put many weep holes in the wall, but
will not design the pool.
A number of years ago, I got a frantic call from a contractor for an upscale
resort/development that was still under construction that a retaining wall
"just went south" as a result of a swimming pool leaking. I wasn't able to
get out to look at it and referred them to another engineer, but did ask them
if the retaining wall had weep holes and if water had been coming out of the
weep holes. "Like Vesuvius," I was told. Construction workers have very apt
ways of describing things!
It seems that most free-form pools function more as a shell than as flexural
members, however, a rectangular pool would seem to behave flexurally, more
than as a shell.
A. Roger Turk, P.E.(Structural)
Nels Roselund wrote:
>>I have a project for renovation of a historic residence that includes a new
swimming pool on the grounds. It is to be a square-cornered pool that will
be finished on the inside walls and bottom with a tile mosaic. It will be
constructed into an excavation into soil.
Where can I find structural criteria for design of this kind of structure?
What kind of recommendations should I request of the soils engineer?
I've got a copy of ACI 350R-89 Environmental Engineering Concrete Structures
that appears to have appropriate guidelines including crack control,
corrosion control imperviousness. Are the criteria in ACI 350 appropriate
for a swimming pool?
I also have The PCA publication "Rectangular Concrete Tanks", 1998 edition
that seems to provide the factors needed to evaluate the moments and shears
in the walls and bottom of the structure.
I visualize designing the empty pool as a tank structure retaining
inward-acting active earth pressure or flooded backfill. Outward pressure
is less clear -- the walls will be confined by passive soil pressure, which
will reduce the net outward pressure, but the relative rigidities of soil
and tank walls would need to be evaluated in order to determine the net
outward pressure -- is that what is done?<<