like he should be battling Namor for control of the
David L. Fisher
and Partners - Cayman
372 West Ontario
Street Georgetown Grand Cayman
Street Boston 02210
Kester, PE [mailto:akester(--nospam--at)cfl.rr.com]
Sent: Saturday, January 31, 2009 11:43
re: thor's pool
I think you have several things to
consider with this project, which you may already be doing. The existing
foundations of the house if within a certain distance (and depending on your
soil) will put a lateral suracharge load on the wall of the pool. Also, you
may have to give the contractor some shoring direction to avoid settlement
issues with the existing house. I would include a preliminary site visit to
review the existing wall and take lots of photographs and document any
exterior and interior cracks, just in case down the road they start making
lots of claims. I don't know the existing home
Also, in Florida, it would be
very unusual I think to use the concrete deck as an apron. These are typically
placed after the entire project is done, and are simply a slab-on-grade with a
textured "cool-deck" topping. More popular now is the use of concrete pavers.
If the owner wants a concrete deck and you can get them to OK your idea, then
I would certainly explain to them this is structural element and cannot
be removed ever (and note that on your dwgs). You may want to recess the
structural concrete apron a few inches from the finished top edge of the pool
so they can place a non-structural cool-deck topping or even a layer of sand
and thin pavers.
My conclusion as well as any
others (as previously stated) on this list is pool design is not an exact
science, but somewhat of a mix of science and art. If the pool is
non-rectangular it will behave more like a circular water tank and the pool
water will balance out the soil pressure and put the reinforcement in tension.
But I don't see how in a rectangular pool the walls, at least while being
constructed and empty, do not act like cantilevered
And I have seen several pools pop
out of the ground when partially emptied during a storm event because of
a high water table. One was up two feet and took the deck with
it, the whole thing was a total loss. As mentioned by others, they do
have valves that are supposed to pop and allow groundwater to enter the pool
to balance the hyrdostatic pressure. But if you design it not to float in the
empty condition with a high water table, and simply add mass in the form of
lots of concrete, I would expect you will have a very angry homeowner and
Conclusion- I don't touch swimming
pools, seems like a no-win. Good luck, and let us know what you come up
"I guess i should. i'm in soft rock and th 9'
end is against the ex.
Andrew Kester, P.E.