Hi, Ted... I just finished putting in a concrete base that needed to be
5'x5'x6'deep. The backhoe operator used a large bucket and the hole ended up
being a little over 5' x 7' x 6' deep. The backhoe op wasn't able to make
the hole exactly square, nor could he make the walls exactly perpendicular.
The larger hole required more concrete... instead of 5.5 cubic yards, it
took almost 8 cubic yards. I don't know what 4000 lb. concrete costs where
you are, but it's not cheap and I ended up paying more than I expected. I
ordered the extra concrete... 8.5 yards just to be sure there was enough
(there's always a little spillage, and it's NOT a good thing if the truck
runs out before your hole is filled). On advice I got on TowerTalk, I had
the guy mix a " 5-inch slump" so it would flow into the hole easily.
But before ordering the concrete, I built a 5'x5' framework around the top
of the hole so the base would end up about 6" above the ground, then I built
the rebar cage and put it in the hole on blocks along with the J-bolts that
the tower mounts on. Then, just to be sure I had done things right, I asked
the concrete supplier to send out a guy to check the hole, tell me if my
concrete calculations were right, and to be sure the truck could get close
enough to the hole. That idea came from somebody here on TowerTalk
(THANKS!!) ...and it's a good thing I did that, because when the truck
arrived two days later it got stuck between two trees and bogged down in the
soft ground, and it couldn't move close enough to the hole. In order to get
the truck out it had to be unloaded, and the concrete guys had to take it
all to the hole in wheelbarrows! Their advance man had said it was OK for
the truck, it would fit between the trees, so I was "off the hook" for all
that labor. I didn't have to argue, I didn't even have to ask...they just
did it... really good guys. Also, thankfully, their man had said that a
front discharge truck would be needed... if it had been a rear discharge, it
would have been a much bigger job.
To answer your question, it would have been nearly impossible to dig that
hole in the ground around here, too much clay and rocks. It was even tough
for the backhoe. Even if it were easy, I wouldn't work in a hole over my
head... too easy to get caught in a slide, especially if you have loose or
sandy soil. Not the way I want to go out, although it would seem to cut
down on burial expenses. My advice is, spend the money and have a machine do
it.
Hope my experience is helpful to you... I learned a lot from it. You
already did the right thing, asking on TowerTalk in advance. I would have
screwed things up REALLY bad without advice I got here :-)... I now have
nearly 9 yards of concrete in the ground, and it cost me more for the
concrete, but that base will probably never move. And I can add some
sections to my freestanding tower later if I want.
73, Jerry K3BZ
----- Original Message -----
From: <k2qmf@juno.com>
To: <towertalk@contesting.com>
Sent: Friday, September 05, 2003 8:41 PM
Subject: [TowerTalk] Tower base hole?
> Hello again All,
>
> I am looking for some help / suggestions on the
> best way to dig a 4 by 4 by 8 foot deep hole
> for my new tower base. Is the old Armstrong
> method best or would a backhoe be best??
> Will a backhoe disturb the earth around the hole??
>
> Any other ideas welcomed...
>
> Thanks in advance and 73, Ted K2QMF
>
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>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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