New twist to in ground pool failure
New twist to in ground pool failure
(OP)
I am a PE and investigated an in ground pool failure where the pool cracked and slightly lifted after a piping failure to the pool heater resulted in emptying the pool in less than 8 hours and the damage occurred that same day. The water released went away from the pool (backyard) to the front and street drains. The elevation of the pool at the rear of the house is higher than the rear boundary which is a golf course. The house has gutters installed directing water away from the pool area.
This occurred in December and there was negligible rain during the month and in Florida this is the dry season of the year.
During the same day, the barometric pressure declined during the dag from 30"Hg which it had been for most of the previous month to a low that day of 29.6"Hg and rebounded the next day to 30.2"Hg.
Usually these events are a result of ground water pressure. Is it possible that the failure could be attributed to increased lateral pressure from surrounding ground fill which was in equilibrium the filled pool, but not when emptied?
Also, would the atmospheric pressure difference be a contributing factor. For a 30"x 15" pool, the reduction in atmospheric pressure noted above is approximately a 28.3 psf or 12,735 lbs. Of course, the water weight removal is over 10 times in magnitude.
Thanks in advance for your opinions,
This occurred in December and there was negligible rain during the month and in Florida this is the dry season of the year.
During the same day, the barometric pressure declined during the dag from 30"Hg which it had been for most of the previous month to a low that day of 29.6"Hg and rebounded the next day to 30.2"Hg.
Usually these events are a result of ground water pressure. Is it possible that the failure could be attributed to increased lateral pressure from surrounding ground fill which was in equilibrium the filled pool, but not when emptied?
Also, would the atmospheric pressure difference be a contributing factor. For a 30"x 15" pool, the reduction in atmospheric pressure noted above is approximately a 28.3 psf or 12,735 lbs. Of course, the water weight removal is over 10 times in magnitude.
Thanks in advance for your opinions,





RE: New twist to in ground pool failure
By the way, I assume you mean the pool is 30' x 15'.
RE: New twist to in ground pool failure
RE: New twist to in ground pool failure
RE: New twist to in ground pool failure
It may be that the rapid emptying of the pool (around 4 hours) caused a stress crack in the shallow bottom that leaked water into the ground that then caused the damage as the other pool areas had no damage. It was 4 months after the event that I observed the damage. Also, the opening in the deck would have allowed rain to penetrate along that side of the pool after the initial damage.
What happened when is the real question.
See the attached pics.
RE: New twist to in ground pool failure
RE: New twist to in ground pool failure
"water below the surface of the
ground, including water which exerts
pressure on, or seeps or leaks through a
building sidewalk, driveway, foundation,
swimming pool or other structure."
Further, the surface of the ground is ambiguous in that there is structural fill put in place to support the concrete decking. For example, what is the surface of the ground under a building that has a perimeter foundation that increases the interior slab height some 2 feet above the original ground level with structural fill? Also, what is the surface of the ground under a highway that has structural fill and crushed rock placed under the asphalt base?
RE: New twist to in ground pool failure
RE: New twist to in ground pool failure
a) regional groundwater level? - you seem to indicate it is below the pool
b) pipes buried below pool - they always leak causing elevated groundwater in vicinity of pools
c) pump broke and somehow the pool drained. - I assume pipe returning flow to the pool broke and water drained to front street
d) pool drained quickly and because of item b), there is now an unbalanced force on the pool
e) shallow end drained empty first
f) shallow end then cracked, relieving the stress
g) deep end then continued to drain out
RE: New twist to in ground pool failure
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: New twist to in ground pool failure
RE: New twist to in ground pool failure
I don't know which side you are representing, but without reading the whole policy, I believe the exclusion would apply. The "surface of the ground" is where the ground is on the day, not where it was at some time in the past. If damage due to water below the ground is excluded, the insurance company will not pay.
RE: New twist to in ground pool failure
RE: New twist to in ground pool failure
"The report is deficient in its factual information as it says on pgs. 24 and 25 that the turn over of the water in the pool is about 4.5 times in a 24 hour period ignoring the loose line to the heater. It then “quibbles” and says it is impossible for the pool to drain completely within a 5 hour period."
I contend that when you disturb the surface of the ground to place structural fill, you have altered the ground surface and this provision in the insurance policy becomes ambiguous.