HELP on Pool wall

[nletchworth]

My name is Nicole and I am hoping someone can help me. We attempted to build an above ground lap pool on concrete. The pool measured 75 feet long, 7 feet wide, and 4 feet deep. We had a liner to hold the water. The rear of the pool and the right side 75 foot wall was the structure of the building (see pictures). The left 75 foot wall and front of the pool were cinderblock that had rebar every 16 inches and then each hole was filled with concrete. We hired a certified contractor to build the wall, and it failed. Now, we think the wall was not supported enough because that 75 foot wall had no supports down that 75 foot run at all- only the rebar. The wall completely fell over in one piece once the pool was about 4 inches from full, so it fell top heavy. See images, it cracked on the corner and it was a horrible mess!! We have now gotten rid of the mess and want to give this another go! We already have this building and do not want to make the lap pool outdoors- we want it in this building.

We would like to make all 4 sides thick wood (2x8) that is reinforced every 16 inches both on the inside and outside of both 75 foot walls, making it a sports bottom pool. Another words, if you are looking at the shape of the pool from end to end,

instead of looking like this I___I

it would be
/I\___/I\

with the I part of this image, each being the 75 foot wall.

We were also going to run a MINIMUM of 4 posts from ceiling to floor (maybe 6 but we are thinking 4)- one on each end and 2 in the middle, all 4 on the left side to prevent collapse of that wall. Everything will be bolted into the slab rather than shot nailed in.

Is this enough support? We feel like we are decreasing gallons by making the bottom a sports bottom rather than flat, and better supporting that left wall that fell, combined with building it from a material that gives more than cinderblock. Would this work???? Any help would be so appreciated!

 

[ANE91]

Water is heavy. Have your builder hire an engineer. What if you were standing outside the leg that fell?

 

[RWW0002]

I think you are lucky that this wall failed. Water pressure can be pretty significant, even at only 4' deep. The masonry wall does not appear to have been designed or built properly, but more importantly, if this wall had not failed your exterior walls may well have failed instead, and brought down the entire building.

I strongly recommend hiring a local structural engineer for this one.

 

[nletchworth]

Yes- we tried to hire a structural engineer to help. We live in a rural area. The closest one is 1.5 hours away and they don't want to do anything because the slab and building are already here- another words they did not start the project, so they don't want to put their name on it now if that makes sense.

 

[TRAK.Structural]

I don't quite understand how you envision the wood framing to be configured, but wood framing does not seem like the way to go here.

As others have stated, you really need an Engineer and I think you should continue to pursue one until successful. It should be noted that the slab thickness and reinforcing is also important to consider here as that is what supports the wall. Any Engineer that you hire will likely need to know this information and may require modifications to the slab.

 

[jerseyshore]

This is such a great visual for hydrostatic pressure next time someone argues with us over a design. Thanks for the photos.

RWW is right, you are lucky it was this wall and not the building. I would not be using a wall of a building holding water anyway.

You should just get a pool guy to build a long above ground pool.

 

[JAE]

You need an engineer and not one from this site - which is not meant to provide free engineering services for situations like this.

 

[SWComposites]

OP - you need rebar in the wall, both horizontal and vertical. And the vertical bars need to go down into the floor/foundation. But you need an engineer to specify the bar sizes, locations, etc. It looks there is some sort of wire mesh in the wall, not structural rebar.

and as far as I know, there is no such thing as a "certified contractor"

 

[Ingenuity]

and as far as I know, there is no such thing as a "certified contractor"

But there are many 'certifiable' contractors (i.e. officially recognized as needing treatment for a mental condition) and seems to be the case here.

 

[Tomfh]

You can do the walls the way you are saying, but you don't need the brace coming into the pool. You only need to brace it on the outside. Like this: /|__|\



A lot of people build DIY timber pools, often with poles embedded into the ground, which provides the same function as diagonal braces.

 

[phamENG]

@Tomfh that timber pool is actually pretty sharp. Or...could be with a little more detail work. Interesting.

 

[gte447f]

At first glance, I assumed the wall was completely unreinforced, but I suppose it probably would not have lasted until the water was 4 inches from the top if that were the case, and the OP says it had rebar at 16" on center. The first photo shows that not to be true, but I do think I can make out a few vertical bars that yielded and bent over at the concrete slab.

Anyway, I am sorry for the OP, but this is one of the funniest engineering related things I have seen in a while.

 

[Rabbit12]

I think the main issue is there are no bond beams in this thing. The vert rebar also looks to exceed 16" but the dowels embed into the concrete sure don't look failed.

Really really lucky someone wasn't between the building and CMU wall when this happened.

 

[gte447f]

This dowel looks failed to me.

 

[STrctPono]

The steel dowels that you have coming out of the floor appear to be offset too far from the inside face of the pool wall. It's hard to tell but the steel does not appear to have ruptured, did they pull out of the holes? Did you even epoxy them in? Non-shrink grout? Did they clean the holes? It looks obvious to me that each cell was not fully grouted and was most likely insufficiently grouted.

The pool is not that deep, and the hydrostatic pressures are not that considerable. There is no reason why this should have failed this catastrophically and there is no reason why you could not have gotten this concept to work if it had just been designed correctly and executed properly.

 

[gte447f]

if it had just been designed correctly and executed properly

Therein lies the rub

 

[Rabbit12]

This dowel looks failed to me.

View attachment 6104

Pretty hard to tell from that picture. I don't think we have a complete breakout cone failure. To me it looks like a spalling around the bar.

 

[Rabbit12]

The pool is not that deep, and the hydrostatic pressures are not that considerable. There is no reason why this should have failed this catastrophically and there is not reason why you could not have gotten this concept to work if it had just been designed correctly and executed properly.

This almost doesn't even need designed (#5 @ 16" work easily). Someone competent in masonry construction could have built this successfully.

 

[XR250]

I think the main issue is there are no bond beams in this thing. The vert rebar also looks to exceed 16" but the dowels embed into the concrete sure don't look failed.

Really really lucky someone wasn't between the building and CMU wall when this happened.

That would have helped but it is too long of a span to do all the work. Proper vertical rebar would be required.

 

[gte447f]

Pretty hard to tell from that picture. I don't think we have a complete breakout cone failure. To me it looks like a spalling around the bar.

Well, either the rebar yielded or their was anchorage failure.