Dick:
I have dug the base hole for my fixed towers with a tractor type backhoe
and have also dug the base with a small excavator. Both worked very
nicely. The problem with both is that it is very hard to do the fourth
wall (the one closest to the tractor or excavator) perfectly vertical.
Since these machines have articulated arms, their tendency is to want to
make the wall closest to themselves at an angle.
I had a tractor type backhoe do the based for my US Towers 89' crank ups
which had 8' deep walls. The operator was able to dig those perfectly
vertical by using a second helper in the hole working with a shovel
after about 4 foot of depth. The operator and worker worked the hole
sequentially, and they did an amazingly nice job, perfectly flat hole
base, and perfectly vertical side walls on a 5 x 5 x 8 foot base hole.
I have done anchor hole myself also and those were a piece of cake with
a small mini-excavator. I also used the mini-excavator to place the
re-bar cages in the holes. No problem. Unless you are looking at
something very very small, the small excavators at equipment rental
places can do that kind of work easily.
Gary W5FI
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Dick Green WC1M
Sent: Sunday, August 27, 2006 1:43 PM
To: Tower
Subject: [TowerTalk] Best way to dig holes
The time has come to dig holes for my 110' of Rohn 55. Mindful of the
Rohn
specification to pour against undisturbed earth, and not wanting to get
into
the business of building forms and backfilling, I had planned to dig
the
pier and anchor holes by hand. But time is running short before the snow
flies in New England. Also, I've switched from the 4a anchor spec to the
4d
anchor spec, which requires much larger holes: 3'x6'x4'. I think I'm
going
to need some machinery to get this job done without spending a huge
number
of hours and what's left of my back.
Is it possible to dig anchor holes that size using a small excavator
without
grossly overdoing it? Has anyone tried using a 1-man or 2-man gas auger
to
do some of the digging, then finish by hand? I'm considering an auger to
do
some of the excavation for the pier hole because I don't think even a
small
excavator can do a 3'x'3'x'4 hole (actually, it only has to be
2.5'x2.5'x4'.) Also, I could use the auger to dig post holes for the
tower
utility panel. Advice from the knowledgeable?
73, Dick WC1M
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