I am constructing my first permanent ABG and have taken the advice given on this forum to heart. I have searched this forum and much of the information either says or implies that there is a crusing weight of water on the pool bottom. Some posts say that the weight of the water will crush a styrofoam bottom or other the pool bottom. It has caused a lot of doubt on my part that I can safely build this pool and why in the world they are allowed to manufacture and sell these pools in such an indiscriminate manner. I decided to apply some basic math to the problem and determined the following:
27' round pool manual says it holds 17,000 Gallons.
x 8.5 #/gallon
= 144,500 pounds of water in pool.
27' pool = 13.5' radius
13.5' x 13.5' = 182.25 sq feet
182.25 sq ft x pi = 572 sq ft of area for 27' round pool
convert area to sq inches so psi can be determined
12" x 12" = 144 sq in per sq foot.
572 sq ft x 144 sq in = 82368 sq in of area in a 27' round pool
calculate psi on the botom of the pool
144,500 pounds of water / 82368 sq in = 1.75 psi pressing on the bottom of the pool.
I feel after this calculation that I can build this pool without having to over build the pool. I am making this post to help allay fears of other people about the effect of the water pressure on the pool bottom. The foam products that are avail in my area have a rating of 10 - 15 psi crush strength so are suitable for my pool. I talked with another local ABG owner that has had his pool for 5 yrs with a white foam bottom that he say had no divots or other depressions in the floor. These calculations seem to confirm this and the white Styrofoam is less expensive.
I have installed the pads for the uprights and am now leveling the pool floor.