Concrete pile question

[Tom Sestito]

Good afternoon,

I am installing a grade beam for a cantilever gate behind my garage.

It requires two 16" piles, 6' down. I had those drilled last week when the ground was still frozen.

The contractor used a 17.5" drill bit.

Because the ground was frozen, the edges of the holes turned to muck. The debris and muck resulted in the overall diameter of the hole being quite a bit less than my sonotube.

So, I slit the sonotube with a skillsaw and dropped them in the hole and carried on.

However, they have retained the 'new' diameter - closer to 14".

I suspect they will expand back to close to their original diameter.

My question is - has anyone done this before and am I correct that the tubes will expand back?

I need this info to ensure I order the correct amount of concrete.

Thoughts or experience would help. Thanks all.

 

[Marctrees]

I'm sure the weight of the concrete will open up the tubes...

BUT you will have air gaps like everywhere between tube and dirt wall.


I see no benefit for tubes in this situation.


Having done similar to your job, I poured w NO tubes.

Concrete ends up totally intimate w packed virgin soil.

My opinion , NOT Pro engineer.

Marc

 

[Tom Sestito]

Having done similar to your job, I poured w NO tubes.

Concrete ends up totally intimate w soil.

My opinion , NOT Pro engineer.

Marc

Thanks for the reply, I had considered leaving the tubes out but with the 4' of frost we get I was concerned about heaving overtime, with the rough edges of the holes.

No expert either though!!

 

[Marctrees]

Thanks for the reply, I had considered leaving the tubes out but with the 4' of frost we get I was concerned about heaving overtime, with the rough edges of the holes.

No expert either though!!

See, you have a very good question I think, because in frost country.

I would want a Pro to answer it if was me.

Marc

 

[jhelrey]

We only use tubes for the first 12 or so inches... then the rest is dirt.

 

[joes169]

You'll certainly want sono tubes to keep the columns smooth so that frost can't pick at the edges. I'd simply order for 16" diameter, even round up 10-15% to be safe, and hope that they expand that much. W/o actually seeing the conditions in person, it'salmost impossible to guess how large they're going to get when they're poured.

 

[Marctrees]

So piles in freezing areas do not rely on skin friction as piles in the south ?

Interested in the dynamics of this.

Marc

 

[didit]

I usually have a form ready where ever needed to use any left over concrete. I think if you tamp it as you go with an appropriate diameter ram, those tubes will expand to their original size.

 

[Tom Sestito]

Thanks all. I calculated the weight of the concrete- each tube (there are two) will weigh ~900 lbs and the beam itself above the tubes will weight ~5,000lbs.

So there will be a lot of pressure to expand them.

I will have a spare form ready in case I have too much concrete - this is an excellent idea.