[TowerTalk] Fwd: Tower Permitting Spec's
Richard (Rick) Karlquist
richard at karlquist.com
Tue May 1 12:10:43 EDT 2018
When I built my first 90 foot vertical, I made the whole
thing out of three 30 foot pieces of 4 inch OD aluminum
irrigation tubing/pipe, guyed at the joints at 30 and
60 feet as well as at the top. I didn't know any better.
It shimmied like crazy in the slightest wind. I
eventually evolved the design to 30 feet of 4 inch,
30 feet of 3 inch 30 feet of 2 inch, again guyed at
30, 60 and 90 feet. It didn't shimmy because it was tapered.
It would survive really bad storms,
only to have the top section buckle 6 months later
in no particularly high wind. I repaired it, and the
same thing happened again. Again, I repaired it, and
again, same problem. Turns out it was
the dreaded aluminum fatigue. The fix was to add guying
at the 75 foot level, in the center of the 2 inch section.
Never had a failure since.
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