Supports for PVC in trench

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JJWalecka

JJWalecka

Senior Member
Location
New England
Table 352.30 (B)
States that 4" PVC should be supported every seven feet.

Would the maximum spacing between supports apply to PVC used in underground Duct Banks?

Is there a concrete consistency requirement?

(Not sure of the correct terminology) #6 is a thinner concrete and a #1 concrete is thicker.

What is better to use for concrete encased duct?

Justin J. Walecka
 
I know that I'm missing something in this post but IMO....
Seven feet
Probably
Whatever the GC is pouring.
steve
 
"Table 352.30 (B)
States that 4" PVC should be supported every seven feet."

As far as I know, the supports in a trench are used to keep spacing around the pipes.

I was not sure if the support requirements would apply to this application of PVC.


Justin J. Walecka
 
IMO you either follow the job specs (if your running duct banks I bet there are specs) or you do what your want.

The PVCs will be supported continuously by the concrete when the installation is complete.

This is no different then direct burial.

Now in my experience I find every 5' a good distance to place spacer chairs with 4" duct banks particularly when they get stacked.

The job specs should also let you know the spacing between raceways.

I prefer a 'stiff' concrete mix as they raceways do not float as much but you will need a concrete vibrator used to get a stiff mix around the raceways.
 
Are you using sch 40, EC, DB....? I assume you are using factory interlocking spacers.

The consistency of the concrete is largely a trial and error...add a little water....no, no, too much...oops...can't take water out...eeek...did we tie it down enough? Oh no..it's starting to float out.

Aint life grand?
 
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