On the subject of where the pieces fall when a tower fails, I was able to obtain
from the ARRL a copy of an engineering study which analyzed failures of large,
commercial, guyed towers. It did show that most of the debris falls close
to the towers.
I was able to successfully use this in a Zoning Board of Appeals hearing to
locate my 100 foot tower only 30 feet from my property line. While I can't
say what would have happened if I didn't have the study available, or if my
neighbors had objected, I do think it was helpful.
My permit allows towers to 100 feet. Yet I will not build it to that height,
as there are 110KV lines only 90 feet away!
On another note; I have a challenge for the readers. I'm a Physics/Ocean
Engineering major from college days, but I recall a classic ME problem
which goes something like this:
The base of a brick smoke stack is explosively destroyed. The Stack starts
to topple. As it falls, at some point, due to the rotational nature
of the fall, the top section of the stack breaks in a direction opposite
from the fall. The study question is where does it break, and why? The
(dimly remembered) answer is: 1/3 of the way down from the top. It breaks
because it is being accelerated by then rest of the tower at a rate
greater than 1 g.
Can anyone out there in towertalk land shed more light on this classic
engineering problem? Obviously, it relates to failing towers.
As for the engineering study, it is quite lengthy and detailed. I think
our esteemed moderator (LXC) has a copy, and perhaps he could be pursuaded
to provide reprints, at a price, for those interested.
-Tony, K1KP, fisher@hp-and2.an.hp.com
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