[TowerTalk] Water in hole for tower base

[Gary and Jane Nieborsky]

Water isn't a major problem provided you have the correct equipment to place
the concrete.  To deal with water you need to place the concrete at the
bottom of the hole using a thing called a "tremmy" (? on spelling) chute.
This makes sure that the concrete gets to the bottom of the hole with the
cement and aggregate mostly together.  Whether there is water in the bottom
is academic at this point because the concrete will force the water out the
top as it fills the bottom.  This device is also used to pour concrete in
really deep holes (>15').  If you just drop it in from the truck at that
height the aggregate and cement part company about 1/2 way down the hole.
The result is not very strong concrete.

If you can pump the water out and have it stay dry while you pour then this
won't be necessary but if not then this is the way to do it.

I've poured transmission tower foundations that have had visible flow across
the bottom and one that we couldn't pump out using a 100 gpm pump.  It can
be done.

Gary K7FR

-----Original Message-----
From: Chris Allingham <ve3fu@rac.ca>
To: towertalk@contesting.com <towertalk@contesting.com>
Date: Friday, August 04, 2000 6:49 PM
Subject: [TowerTalk] Water in hole for tower base


>
>I dug a hole for my tower last summer but didn't get a chance to pour the
>concrete.  With all the rain we've had this summer, the groundwater level
>is higher than last year.  As a result, the hole fills up about half way (2
>feet) after a day or so of rain, but slowy drains away during the dry
>spells.  Only once this summer has the hole been completely void of water.
>
>Is this something I should be concerned about once the tower is up?  Do I
>have to order a special concrete mixture to account for the extra water?
>Before pouring, I plan on waiting until the hole completely drains again,
>or renting a submersible pump.
>
>Thanks in advance!
>
>
>Chris VE3FU / VO2AC
>
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