This is scarry !
ALL of my 7 towers are guyed to screw anchors.
The taller ones (95, 130, 135 ft) use two anchors
in each direction with the first anchor spaced 60 ft
and holding guys at 30 and 60 ft. The second anchor
is typically spaced 95 ft for the upper one or two sets
of guys.
Fortunately, they have held up through a small
tornado 6 years ago and estimated 70 mph winds
this past summer so I *assume* they are still sound
but it would be nice to have a better way of knowing!
Some of my early anchors are heavy duty (painted)
mobile home anchors (20 years and counting) and
the newer ones are galvanized.
I went ahead and used screw anchors because they
are relatively easy to install (after it rains) and I had
heard a second hand report that WA4SSU had tested
a screw anchor in Georgia Clay by hooking a crane
to it and crane off it's back supports. (Makes a good
story anyway). Alabama clay gets as hard as brick
in summer.
Anchor ROD deterioration is a problem for BOTH
screw in anchors and concrete anchors. Screw in
anchors have the additional risks of having more
exposed shaft underground and the integrity of
of the plate weld at the bottom.
SO....any ideas on how to test the integrity of
long term anchors in the ground?
de Tom N4KG
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