[Towertalk] Inquiry - Tower Collapse/Fall/Radius Zone

[Pete Smith]

At 06:46 AM 4/9/02 -0600, n4kg@juno.com wrote:
>...
>
>You delude yourself if you seriously believe that amateur towers
>(mostly Rohn 25 and 45) COLLAPSE when they fail.  In a private
>response I provided numerous empirical examples of towers that
>fell out to their FULL HEIGHT, mostly due to human error or
>defective guying hardware. I understand the motivation to avoid
>overly restrictive setbacks but burying your head in the sand
>to the FACT that MANY amateur tower fairures fall their entire
>length does not seem like a good approach.

I've said this before on towertalk, but it seems to me that one tradeoff 
might be to permit a setback smaller than the guyed tower height IF the 
guying scheme uses more than one guy anchor per direction and divides the 2 
or 3 guys on each between them.  That way, no single point failure could 
ever result in a "falling tree scenario", and the guys would serve to 
tether a collapsing tower to a circle well inside the guy radius.  For 
example, if a top guy failed, the tower would probably fold above the 
second guy set, within a radius set by the distance between the top guy set 
and the next one down.  If an intermediate guy failed and the tower 
buckled, the top guys would serve to tether the wreckage inside a 
relatively small circle.  The geometry of all that is fairly simple -- just 
a bunch of right triangles.


73, Pete N4ZR

Check out the World HF
Contest Station Database at
www.pvrc.org