Code specific to swimming pools 4

[Iasonasx]

I encountered for the first time in my career an issue with a swimming pool. I never designed one so far. I was wondering if there is any specific code by the ACI on this matter. I would assume that ACI 318 and the IBC should be the default codes to refer to. The actual problem was with rebar being too close to the surface and moisture went through, so now we see rust coming out. The swimming pool is used with saline water to emulate seawater, but I think that should not be an issue, and I say that thinking that if the proper coverage was applied, there should be no problem for any type of water (saltwater or chlorinated) to cause rust to the rebar. The location of the rebar is about 3/4" from the surface of the water at those two locations, which is definitely not ok with the ACI 318, to begin with. Please advise if there is any other code I should refer to. Thanks

 

[phamENG]

Don't think so. These guys are self-proclaimed pool engineering experts and they quote the standard ACI 318 clear cover reqs.

 

[Celt83]

While not specifically applicable or required for swimming pools you could look at ACI 350 for some additional recommendations.

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[Iasonasx]

Thank you both phamENG and Celt83. That's what I thought and it confirms it.

 

[JoelTXCive]

I have not read it, but ACI does have a shot-crete manual.....

There might be good info on cover and other rebar detailing items in there.

 

[Agent666]

Every swimming pool I've ever done has had a waterproof mortar applied in one form or another... It's been my experience that there is never the raw concrete finish directly against the water. But we still follow our concrete code minimum covers plus any applicable tolerances.

 

[JoshPlumSE]

One of my good friends used to work at Pool Engineering. They did an insane number of pools every week. And, I did a little "side work" for them at times. Ron Larcher, the founder and real expert at that company, is basically retired as I understand it. And, his two sons (only one of which is an engineer) are running the company.

The swimming pools are almost always designed as cantilever retaining walls, were the worst case load condition is the empty pool. Shotcrete over the rebar for construction. They may have had additional requirements related to cracking or cover. But, I was only involved with weird "one-off" projects (dynamics of a pile supported pool, or a cave like "grotto" or water fall).

 

[KootK]

The book Basics of Retaining Wall Design has a single page on pool design.

I've always found pool design kind of intimidating owing to the seeming lack of standards and design guidance. Seems like it should be easy and something that I already know how to do but, alas, I don't. The basic boxes aren't too scary but the ones that are all curvy in cross section freak me out.

 

[JoshPlumSE]

KootK -

That's a good reference. It covers all the basics of pool design. I should point out that almost never is the "curvature" of the pool considered in the design. Neither horizontal curvature or vertical.

It can be reasonably assumed that the consideration of curvature would reduce bending moments. Or, convert some of the vertical reinforcement into horizontal reinforcement. All I'm getting at it the traditional methods of analysis / design for retaining walls end up being conservative for the most part.

 

[JoelTXCive]

One of the local geotechs does an annual presentation at the Houston Builder's Association and also the local foundation design group.

He has all kinds of photos and horror stories of empty swimming pools popping out of the ground due to hydrostatic pressure. Most contractor attending for the first time walk out of the meeting scared to death.

I think it is rare when the average backyard pool gets engineered. Normally, a guy just shows up with a bobcat and starts digging.

 

[KootK]

All I'm getting at it the traditional methods of analysis / design for retaining walls end up being conservative for the most part.

Thanks. That's just the kind of simplifying assumption that you really need an insider to tell you about.

The book below is pretty great, especially for commercial pools. It covers pretty much everything but structural design. I like having an inside track on what the pool consultants are harping on about.

 

[Agent666]

That minimum level of reinforcement is probably good for a 3' deep pool.... for real design you'll be limited by crack widths, limiting steel stresses and thermal effects.

Essentially follow any water retaining code as a basis.