Re: Falling Towers and radius of destruction
Several hopeful city dwellers have made inquires about the report that
LARGE towers fall in a radius of approximately 1/3 their height. They
hope to use this MISLEADING information to convince city fathers to
allow towers which could fall on neighboring propertly.
Amateur towers are relatively short (usually <100 ft) in most residential
areas. Such towers rarely have the mass to collapse in a concentrated
small circle. In the event of a GUY WIRE or ANCHOR failure, they
usually
fall STRAIGHT OUT to their full height. I have seen several such
instances
with 40 to 100 ft towers, most caused by the guy wire pulling through
cable clamps which presumably loosened over time. Anchor failures
and even an equalizer plate bolt failure all resulted in straight out
falls.
Just last week, a local lost a 90 ft Rohn 25 tower and TH7 when his
anchor bolt pulled through a large (telephone) pole used for his elevated
anchor supports. The pole was next to a garage and over the years
had rotted out from the extra water channeled towards it from the garage
roof. The tower fell straight out to its full height, landing in his
next door
neighbors back yard.
DON'T FOOL YOURSELF into thinking that your tower will not fall out
to it's full height in the event of a support failure. Be sure to use
adequate
anchors and guy wires. IF you use cable clamps, be sure to inspect and
tighten them ANNUALLY. I prefer using guy grips at every junction, even
at ground level. I have NEVER seen a guy grip failure.
I am a big believer in redundancy. For my taller towers, I use TWO
anchors
in each direction. This way I am not dependent on only ONE of anything
to
keep the towers up. Also, in the event that I do have a SINGLE support
failure,
it IS more likely that the tower will buckle and NOT fall out to it's
full height.
de Tom N4KG
_____________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|