Bonding a concrete shell pool that was constructed using fiberglass rebar

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Jim Brown KS

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Is it theoretically possible to use a water bond to effectively bond a pool with a conductive pool shell that used fiberglass rebar instead of steel rebar? The code requires a water bond when you have a non conductive pool shell but does that same water bond provide the needed protection if the conductive pool shell was not constructed with the bonding grid?
 
Is it theoretically possible to use a water bond to effectively bond a pool with a conductive pool shell that used fiberglass rebar instead of steel rebar? The code requires a water bond when you have a non conductive pool shell but does that same water bond provide the needed protection if the conductive pool shell was not constructed with the bonding grid?
No, the water bond does not bond the conductive shell. Where the shell has non-conductive rebar, it must be bonded per 680.26(B)(1)(b). There are no exceptions or short cuts....if the pool was constructed without installing a bonding grid, the shell must be removed and a grounding grid installed.
 
I've done several concrete shell pools with fiberglass rebar. At least that's what they called it. All I know is it isn't conductive.
Owens Corning does make a fiberglass rebar. I'm not sure how one would deal with specific bends as it's needed on any of mine or anyone building gunite pools. Would be a tough sell to me and my structural engineer.
There has been experimenting of fiber reinforced concrete used in place of rebar. We have used it on flat work years ago and am not impressed. The fibers come to the surface when finishing. Same was noticed on pools that the fibers had to be ground off the surface so as to not to intefere with either a painted finish or a plaster finish in my trade.
 
For clarification it is fiberglass rebar not the PVC, fiberglass or micro-twisted fibers that get mixed in with the concrete.
 
What did you do to bond the shell?
These pools were concrete with a vinyl liner. The vinyl liner makes them non-conductive. However, I had to bond the metal track for the liner. It was in several pieces and each section had to be bonded together. I used #8 encircling the pool and a jumper from the metal liner track. I don't think that was necessary since the track was covered with pavers. But I didn't win that argument.
 
No, the water bond does not bond the conductive shell. Where the shell has non-conductive rebar, it must be bonded per 680.26(B)(1)(b). There are no exceptions or short cuts....if the pool was constructed without installing a bonding grid, the shell must be removed and a grounding grid installed.
If an engineer wants to design an alternative to the prescriptive code requirement is it theoretically possible to use water bonding as a solution since the conductive concrete pool shell is porous? If they want to design an equivalent and test it, is it possible? Currently Section 680.26 (1) allows for protecting the water through the conductive porous pool shell with a shell bonding grid. If that works, would it be possible to reverse engineer that connectivity by bonding the water to achieve the same result?
 
If an engineer wants to design an alternative to the prescriptive code requirement is it theoretically possible to use water bonding as a solution since the conductive concrete pool shell is porous? If they want to design an equivalent and test it, is it possible? Currently Section 680.26 (1) allows for protecting the water through the conductive porous pool shell with a shell bonding grid. If that works, would it be possible to reverse engineer that connectivity by bonding the water to achieve the same result?
If he wants to put his stamp on it, fine, but even with a PE stamp on that design I would not be the contractor working on that pool, and if I was the AHJ, I would red tag the installation.
 
There are no exceptions or short cuts....if the pool was constructed without installing a bonding grid, the shell must be removed and a grounding grid installed.
Trying to understand the meaning and intent of 680.26(B)(1)(b). Is the bonding required in the walls of the pool, the bottom of the pool, or both? (2) and (4) refer to the "contours of the pool" but I find that term ambiguous.

If only the walls need bonding, and they are still exposed/exposable, then the copper bonding grid could be attached to the outside of the concrete shell and then covered a couple inches of additional concrete.

If the bottom of the pool needs bonding as well, then if the shell everywhere is 6" thick or less, the bonding grid could be added to the inside and again covered with a couple inches of additional concrete.

Cheers, Wayne
 
Trying to understand the meaning and intent of 680.26(B)(1)(b). Is the bonding required in the walls of the pool, the bottom of the pool, or both? (2) and (4) refer to the "contours of the pool" but I find that term ambiguous.

If only the walls need bonding, and they are still exposed/exposable, then the copper bonding grid could be attached to the outside of the concrete shell and then covered a couple inches of additional concrete.

If the bottom of the pool needs bonding as well, then if the shell everywhere is 6" thick or less, the bonding grid could be added to the inside and again covered with a couple inches of additional concrete.

Cheers, Wayne
In my opinion the part of the pool that holds the water is the shell and that will include both the bottom and the walls.
Yes, if they would resurface the inside of the pool and install conductive reinforcing or a copper grid in the resurfaced material it would meet the code requirements.
 
In my opinion the part of the pool that holds the water is the shell and that will include both the bottom and the walls.
Certainly I agree with that, but I'm trying to figure out the meaning of the term "contour of the pool (shell)" used in (B)(2). If they used the term "full surface of the pool shell" that would be clear; is "contour" necessarily the same thing as that? In other contexts (say a contour map), a contour would be just the horizontal boundary, so it's not clear to me the language includes the bottom of the pool.

On a related note, (B)(1)(a) doesn't specify the extent of the rebar. If you had a pool with rebar in the walls and none in the bottom (for whatever reason), I don't see any reason that wouldn't comply with (B)(1)(a). In which case rebar or even steel mesh could be retrofitted to the outside of the shell and covered with the necessary 3" of concrete to create the pool shell bond.

Cheers, Wayne
 
Certainly I agree with that, but I'm trying to figure out the meaning of the term "contour of the pool (shell)" used in (B)(2). If they used the term "full surface of the pool shell" that would be clear; is "contour" necessarily the same thing as that? In other contexts (say a contour map), a contour would be just the horizontal boundary, so it's not clear to me the language includes the bottom of the pool.

On a related note, (B)(1)(a) doesn't specify the extent of the rebar. If you had a pool with rebar in the walls and none in the bottom (for whatever reason), I don't see any reason that wouldn't comply with (B)(1)(a). In which case rebar or even steel mesh could be retrofitted to the outside of the shell and covered with the necessary 3" of concrete to create the pool shell bond.

Cheers, Wayne
Contour only refers to the shape. The bonding must follow the exterior contour (shape or surface) of the pool shell.
I would reject any installation that does not have the conducive bonding material in all of the surfaces in the pool. The big loop hole is there is nothing to specify the spacing and how much conductive rebar is needs for a pool with conductive rebar, but if you don't have the conductive rebar, you need need a 12" x 12" copper ground grid.
 
For clarification it is fiberglass rebar not the PVC, fiberglass or micro-twisted fibers that get mixed in with the concrete.
I understand. I was just mentioning a different for use fiberglass in relation to concrete. Fibers added to concrete are supposed to replace the use of rebar or concrete wire mesh. I'm old school. I even use rebar when we form and pour our equipment pads.

They have experimented with concrete swimming pools using fiber in place of rebar. Just not on board with that.

I suspect old schoolers would be skeptical about the use of fiberglass rods in place of steel rebar as I am.
 
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