Remember the goal is not to provide x-lbs of concrete to hold the
load, but to provide a device that requires movement of x-yards
of undisturbed earth. A flat sided device will require more earth
to be moved per yard of concrete, than does a round device.
And a lot more than concrete poured with a sharp edge toward the
tower.
The engineering involved is not that complicated.
I am a firm believer in -NOT- backfilling. If you dig the hole
too large, fill with concrete. adding large rocks is a good
replacement for excessive concrete. (Cement is only a glue to
hold rocks together. Concrete is cement with a whole bunch of
little rocks) Rocks are inherently stronger than concrete and when
properly used, actually strengthens the mix.
de KL7HF
At 09:28 PM 6/29/97 -0400, you wrote:
>
>On Sun, 29 Jun 1997 15:50:15 -0400 Bruce Makas <k1my@nlis.net> writes:
>>It seems to me that it would be easier to drill round holes with a
>>tractor
>>powered post hole digger for the guy wire anchor points than try and
>>dig
>>them by hand. If I use the same amount of concrete as spec'd by Rohn
>>for
>>their rectangular anchor, wouldn't I be OK? For anchor "4b" that would
>>be
>>.67 yards.
>>
>>Let's see, 3.14(1)(1)=3.14 sq ft circle and 9cu ft (.67 cu yd) = 6
>
>Ah ... a cubic yard is 3 x 3 x 3 or 27 cubic feet.
>27*.67= 18.09 cubic feet required (using your figure)
>18.09/3.14=5.76 feet depth required for 1 foot diameter;
>18.09/6.28=2.88 feet depth required for 2 foot diameter.
>
>
>Not sure whether I'd try to second guess the engineering.
>
>73,
>
>Rick, WB3EXR
>
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