Pool Design - Panelized Liner System

[RFreund]

Here is the situation:

The owner would like to install a pool system which is a panelized pool system similar to these here:

http://www.hydrapools.com/products/pinnacle

The village requires the pool to be designed for full and empty conditions.

The panels are 42" tall but the pool is 8' deep. The pool is only lined with 2" poolcrete so there is a large unsupported span. See the attachment sketch (sorry its very rough). According the installation contractor and a couple manufactures pools are installed like this quite frequently and have been left empty for a number of months.

Has anyone seen this before? How does a 2" unreinforced 'retaining wall' work here? Some sort of plate/shell action?
Even if this is not "certifiable" how are these systems stable in reality?

EIT

http://www.HowToEngineer.com

 

[JAE]

I've had this issue before as well where we, as "good engineers" want to design the pool for all loading conditions and these will include lateral earth pressure on an empty pool when they empty it in cold winters or to do painting/maintenance.

There are a lot of pool companies that use the thin shotcrete concept which doesn't account for a full earth load on an empty pool. They are depending on the chance that the full lateral earth loads will never develop, or if they do, will develop slow enough such that the pool would be filled prior to any movement/cracking/failure.

If the village requires the empty pool loading condition, then this system doesn't work and can't be accepted.

 

[RFreund]

Thanks JAE, I figured that had to be the case.

EIT

http://www.HowToEngineer.com

 

[PMR06]

FWIW, my father in law just built a pool with a similar system. At the deep end, the pool walls are not 8ft deep vertical down to a radius'ed bottom. Starting at the bottom of 42" panel, the bottom slopes at 45 degree angle to the bottom. Thus there might not be a vertically spanning "retaining wall" to worry about.

I'd contact the manufacturer and verify the detail at deep end.

 

[RFreund]

PMR06 - Thats for the info. Also I did contact them and verify the detail, which leads to why I'm kinda baffled. I mean according them its done everyday, and its not like you see pools failing all over. And when they do have problems it is usually due to high ground water.

EIT

http://www.HowToEngineer.com

 

[a2mfk]

Personally, I would run away from this project. Seems VERY high risk, as I have no idea how that would work.

I just did a forensic job here in Florida of a pool that was maybe 4' deep that used some type of sheet/panel wall system. It bowed in significantly during TS Debbie when there was flooding. I don't know if the homeowner lowered the pool level, or just the submerged soil lateral pressure was enough to cause the failure.

The system itself seems OK if you do not exceed the depth of the panels and stay within the manufacturer guidlines.

Off topic- I think the deep pools have fallen out of favor. Having spent a significant time in and around them, hardly anyone uses the deep end of the pool. We will eventually put in a pool and I don't see the sense in going over 4-5 feet. Nobody is having a diving competition, mainly people are just standing around with a beer in hand hopefully....

 

[ztengguy]

Ask them to provide signed and sealed calculations for the project. There you go.