Swimming Pool Design at the Top of The Building

[JoeH78]

hi all,

I would like to hear from your experiences, what's the design criterias for the swimming poool, located at the arbitrary storey of residential building.

How actually the leakage is been prevented?

Regards,

 

[msquared48]

Check with the local Fire Marshall to see how much water he wants stored up there to mitigate a sprinkler system - kinda like "The Great Inferno" scenario.

A couple of other thoughts on the matter:

If it must be inside the building, vent the area well and use PT wood to mitigate rot of any wood framing.

During a seismic event, you will get sloshing of the water which will cause leakage to anything below.



Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[JoeH78]

I really admit that I'm asking something specific on it's own and just describe it with 2 sentences, and trying to expect from peoples to give me the exactly the missing part of puzzle.

msquared48 you could be a bit more gentle with that, although I was expecting absolutely soemthing like that from collegues it's okay .

Is it too radical to design a swimming pool in residential building (so to speak, lunatic fringe)?

Regards,

 

[msquared48]

It's not radical, but does complicate, and increase the cost of the structure immensely when placed high in the structure.

Better on the ground level as is the norm.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[dik]

In addition to waterproof and rotproof... there will be an increase in humidity that must be accommodated mechanically as well as with the building design.

dik

 

[wiktor]

The leakages are prevented by installation of secondary pan below the swimming pool. Same apply to the sloshing of water during biblical seismic event, which in typical building is rather unlikely and will not cause sloshing, as the main period will be 0.5-2 seconds. The design criteria are as for typical supported swimming pool.
Assume that the pool is filled with water to the top, as this could happen.
The presence of big water body could be beneficial for the seismic performance, and the swimming pool located at the top (or near the top) could be used to feed sprinkler system as secondary (or emergency) water supply.
A swimming pool installed on the top of very tall building could be extremely useful in case of major fire, especially when power supply and water supply lines are cut.

 

[MiketheEngineer]

Put a drain pan underneath. Check seismic loads when pool is full.

Might want to put up "walls" around pool in case of seismic event..

Figure a way to quick drain it in case of emergency and make it available to fire fighters if need be.

 

[hokie66]

I agree that the water can be used for firefighting, and the mass would have an effect, whether detrimental or beneficial, in seismic response. I don't think that a bit of spillage in an earthquake is a big issue.

Swimming pools in residential buildings are common, if you are talking about apartment buildings or hotels. They are invariably of reinforced concrete construction, and should be designed as water retaining structures. A pan underneath is not a bad idea as a "belts and braces" approach, but is not commonly done.

 

[connectegr]

If the structure is steel, make sure the steel is coated appropriately. I recently consulted on a residential pool and concrete deck supported over a cliff. After just 7 years the un-coated steel trusses are significantly corroded and deflecting inches even with an empty pool. The trusses and deck structure were set before the house was built, and access for repairs is gone.


Great view though!

http://www.FerrellEngineering.com

 

[JoeH78]

Thank you all for commenting,

IMHO, statical and dynamical part of problem can be alleviated, even though it poses some serious problems for design. Vertically supporting pool(30m x 15m x 1.5m ) at the top level requires structural element, shear-wall, but people(contractor) will not be happy to see that shear-wall is built just only to support pool. So it means, that architectural design as well should taken deliberately.

Trying to support it with girder and braces means having a reverse pendulum at the top of the building which will drastically effect the natural vibration modes and so the base shear etc..

Additionally to what code requires for static and dynamic analysis mode superposition etc.., I would apply the TH for pool filling and emptying (any sinusoidual, ramp function will serve that purpose in my idea), bcoz I've really seen such collosal amount of water when gushing from pipes into pool and wondered how it really affects the period of building, because we talk about 675tons on storey level that's not negligible.

Does any of you attepted to model such a structure with nowadays s/w Ansys, SAfe, etabs, StaddPro etc.. to see the response of structure?


If most of you suggest that I should use drain pan under the pool then this naturally turns out to be that the pool will leak one way or the other, not by the sloshing but by tiny crevices formed in the concrete during the hardening part?

Is that drain pan something like another RC slab under the pool or is it completely different type of material e.g. composite, coated steel sheet, etc.. Just serving the purpose of basin.

In my idea this is one of the most important part, how can be prevented the leakeage through walls of pool from that tiny crevices?
Firstly, epoxy coating at the inner surface of pool comes in mind.

Your comments will be appreciated.

Regards,

 

[hokie66]

My comment stands. Design it as a water retaining concrete structure, which requires lot of reinforcement. Then if you are not confident with that, use an internal flexible membrane, not an epoxy coating. The pan idea doesn't ring true to me, maybe because I have never seen it done.

 

[JoeH78]

My comment stands. Design it as a water retaining concrete structure, which requires lot of reinforcement. Then if you are not confident with that, use an internal flexible membrane, not an epoxy coating.

What makes me inconfident about that is, the more reinforcement doesn't prove that it'll never crack, I've seen a situation and quite suprised where walls and slab of pool is over-reinforced, there is not even a tiny deflection (approx. in 8mt span) under the poll undder that heavy load but it's still leaking, from sides and bottoms.

And yes that epoxy coat is very brittle and not flexible material , shouldn't be an option here.

In my opinion and almost convinced about that, leak preventation can't be achieved barely with concrete strength increase or over-reinforcing etc.. Some other precationary steps should be taken, probably with water repellant chemicals in concrete and last option revealed from google search is lining. I actually was looking advice from someone who has already done and succeded it.

Thank you all for commenting,

 

[ron9876]

Hot dip galvanized reinforcement, low water/cement ratio and detail a system to catch water when it leaks.

Last one I designed was elevated a couple of feet over a floor slab. We put concrete curbs around the perimeter and added a membrane on the floor to build an area to contain the leaks.

 

[DST148]

@joehigashi: Recently we had a leisure pool, recessed into the roof of a 15 story reinforced concrete building. The depth of the pool varied from 2 feet to 5 feet. We provided concrete tub directly below the pool. The tub was made up of concrete slab on upturned concrete beams spaced at about 6 to 7 feet and a 6 in. continuous ledge around the perimeter of the pool. The pool proper was made out of steel shell(liner plates) field welded to horizontal and vertical steel framing (supplied and installed by pool contractor) supported on upturned concrete beams and the ledge. The concrete tub supporting the pool steel framing was designed per ACI 318. The pool had its own draining system and was connected to the building drain. The top of the concrete slab (tub) was pitched and connected to drain. The apartment below had a high ceiling due to recessed pool above.
The pool is used only during the summer months and empty / covered during the rest of the year. The water in the pool was not counted upon for fire fighting purposes.