On 2/12/2014 10:00 AM, K7LXC@aol.com wrote:
Howdy --
I'm trying to get an idea of a good size for a 6' elevated guy anchor
(with 4 feet in the ground and it'll have a backstay). It's for 100' of
45G. I was thinking of using an 8" flange length. That might be enough since
it'll be backguyed but since I'm not an engineer, I was looking for some
feedback on this. TIA.
37
Hi Steve,
From my web site : "*Each guy anchor is a 16-foot long 5-inch diameter
steel pipe which weighs about 300#. Those pipes set down into the
crushed rock base on top of which is poured the two yards of concrete.
The top of the concrete form is roughly two feet below the surface.
Pinned in place on top of the concrete and welded to the 5 inch pipe is
a brace made of heavy 4 inch I-beam and 5 inch channel, three feet high
and with a three foot base. Here, I managed to get a lot of practice
welding. In particular my vertical welding improved drastically."
So mine are about a foot or so, deeper and in roughly 2.4 yards of
concrete. With steel, including braces, I figure each guy anchor weighs
in the neighborhood of 17,000#
A lot depends on the soil. 2 of those elevated anchors look like they
did when I installed them. The one to the NW has tilted ever so slowly
and the top is now close to 10" out of vertical after 12 years (give or
take).
These are not back guyed and because of the soil I had to build
forms.There was no "undisturbed earth" available. Back guys to the S
and NW would have been in the neighbor's yards. Pulling those forms was
something else. http://www.rogerhalstead.com/ham_files/tower17.htm
http://www.rogerhalstead.com/ham_files/tower18.htm
Unfortunately I don't find any photos of the actual, finished posts or
pulling operation. We just had to yank the walls out which by the time
the concrete had cured were pretty flimsy due to ground moisture/water.
If I had to do it again, I'd use 2 X 4s to fit the outside, but not
fastened to the walls. When finished, I'd pull the walls and leave the 2
X 4s instead of having to pull the whole form in one piece. They really
lost their "structural integrity" anyway. Remembering that wood forms
are pretty much disposable.
73
Roger (K8RI)
*
Cheers,
Steve K7LXC
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