# Bad time of the year for a duct bank



## Slay301 (Apr 23, 2018)

Dump some clean rock on top and if it fills up dig down to the rock of it doesn’t cover it with concrete


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## 210860 (Apr 12, 2021)

My time here Pacific Northwest, seeing something lil' different regarding the same application, but different from Eastern location, so I'll run this by you gpop.

Out here in Pacific North West, they use aluminum 4' x 8' lab-wire sheets (same as seen on plaster walls) and thin gage.. That's what duct banks are formed with and it's reasonably cheap & easy to cut, work w/ too... Line both sides of "inside" of trench w/ lab wire sheets to required width duct bank. that you need. Intermitting stake it out w/ EMT & tie, w/steel tie-wire for the wall supports.

It builds a really strong duck bank form wall, and concrete doesn't filter through the lab-wire to really any degree, (look like it's sweating).. It will keep the dirt walls (and mud) from collapsing onto your conduit, in your duct bank. And no need for removal, unless you so choose afterwards (it's your form), pour it "in place"..

And as to the bottom floor of duct bank... Gravel does makes great "french drain".. But noticing your living in Florida gpop, so assuming a "sand floor" possibly cheaper @ 4" depth on floor.

No digging or cleaning-out of trench required, before the pour..

Gpop, (grin'in) welcome to Pacific Northwest's method of duct bank installation...

I do hope this idea helps.. And have safe day @ the office..


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## Jlarson (Jun 28, 2009)

Sloping/benching sides, keeping the spoils swept wayyy back, dig some sumps in with gradual slopes to them so you can toss pumps in them. I especially put extra time into keeping the high traffic areas of the trench as low mud as possible.

That stay form works great too, and not just for duct bank, all sorts of concrete nonsense lol


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## Southeast Power (Jan 18, 2009)

gpop said:


> I was meant to install a concrete duct bank 6 months ago when it was dry season. Now its raining everyday so the trench which should have been nice and neat is a sloppy mess and the concrete company is talking about 2 weeks from the time i order it.
> 
> Wood shoring sounds like a pain so i was wondering if there was any other options like a silt fence to stop the trench collapsing.


The length of the trench will help with our replies. 
If its 30', that's quite a bit of a different answer than 300' 
Width? is it a foot wide or four feet wide?


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## Southeast Power (Jan 18, 2009)

We had an airfield lighting job where we were installing 10- 4" PVC as a backbone with several smaller loops and spurs. 
Each manhole to manhole was about 500'.
The conduits were to be installed at an elevation below the water table.
The trench was dug, the ducts were assembled next to the trench. 
On concrete day, the duct bank was filled with water and tossed into the trench, concrete was poured directly in the trench on top of the ducts.
The concrete displaced the water. 
Miles of it was installed with very few incidents.
Keep in mind that this crew didn't start out knowing exactly how it would work but, it did.


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## gpop (May 14, 2018)

Southeast Power said:


> The length of the trench will help with our replies.
> If its 30', that's quite a bit of a different answer than 300'
> Width? is it a foot wide or four feet wide?



It's 8 x 2" pipes stacked in 2 layers of 4. Closest bucket we have for the big excavator is 24".
We are hitting a lot of cat rock so its not going to be the neatest trench to start with. If we have to use forms then im guessing we will need to open the trench to 5' wide


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## 210860 (Apr 12, 2021)

*Post # 4.. Jlarson..*

*Thank you for putting a name with the product.. @ the moment of my posting.(#3) could not remember the product name..

* "Stay Form"* .. And yes it's a great product to work with, for the application..


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## gpop (May 14, 2018)

Rained last night and the trench collapsed. 










As you can see its a little rocky. 

Going to open it up to 6' and dig a channel to the hole on the right so we can keep this mess pumped out so we can set forms.


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## gpop (May 14, 2018)

Dell3c said:


> *Post # 4.. Jlarson..*
> 
> *Thank you for putting a name with the product.. @ the moment of my posting.(#3) could not remember the product name..
> 
> * "Stay Form"* .. And yes it's a great product to work with, for the application..



looking for a local vendor to see what it costs. Any ball park figure?


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## gpop (May 14, 2018)

Southeast Power said:


> We had an airfield lighting job where we were installing 10- 4" PVC as a backbone with several smaller loops and spurs.
> Each manhole to manhole was about 500'.
> The conduits were to be installed at an elevation below the water table.
> The trench was dug, the ducts were assembled next to the trench.
> ...


Engineers first duct bank which he cut and pasted from a different print. So he wants to see it before the pour and its seriously over designed with lots of rebar.


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## 210860 (Apr 12, 2021)

gpop.. That's quite a bit of water..

I can't help on cost estimate.. But Stay Form products, being list @ website of... Amicoglobal.com/stay form-concrete-form 

If the site fails opening w/ that link, manually type same into search bar. They possibly can direct you locally for distributor.


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## Jlarson (Jun 28, 2009)

That's gonna be a mess, if we know we're gonna get a lot of rain overnight/weekends we'll leave 2" electric trash pumps with piggy floats on places to drain things. 

It's been a while since we did a stay form job but right now I'd imagine high 20 a sheet right now, better then plywood lol.


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## 210860 (Apr 12, 2021)

gpop.. I did notice on Amicoglobal site w/photos of duct bank installations provided via their product use, one location being highlighted "Turkey Point Power House".... 

* In that respect, product is being utilized locally in your area.. gpop, have a safe day @ the office..


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## gpop (May 14, 2018)

Jlarson said:


> That's gonna be a mess, if we know we're gonna get a lot of rain overnight/weekends we'll leave 2" electric trash pumps with piggy floats on places to drain things.
> 
> It's been a while since we did a stay form job but right now I'd imagine high 20 a sheet right now, better then plywood lol.


I requested the underground crew drop off the mini bulldozer, road roller and larger excavator which got them all excited (that was the plan). They have no choose but to give me what i request so now they have deiced that they can break free from what they were doing and show the dumb arse sparky how you do the job.

By next week i should have a nice dry 6' wide trench with 4 inches of compacted sand in the bottom


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## gpop (May 14, 2018)

They asked why we did not use a trencher


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