[TowerTalk] Guying a self-supporting tower - NO

[Jim Lux]

> Since this has been discussed extensively before, I hesitate to
> ask this....
>
> But I would really like to see an example (with a little analysis)
> of a self support structure of ANY kind that is compromised by
> sensible guy wires. By "sensible" I mean guy angles that are not
> steep, and guy strand that is sized for the structure *top*, and
> pre-tensioned at normal values. I'm really curious about this. I've
> seen lot's of pronouncements, but little substance to support the
> idea that self support structures should never be guyed. I fully
> understand that some might be wary of the issues because of the
> idea that encouraging overloading of towers might result, but this
> is an interesting topic, academically.

I think there has been some examples posted in the last couple years..

Off hand, here's the problem I would contemplate:  Increased down force from
the guy tension will increase the compressive load at the base.   Whether
it's a problem is another issue.  A self supporting tower will be generally
stronger than a guyed tower of the same height (because it has to support
the bending loads, which manifest themselves as compressive loads at the
base). When you guy, you're turning some of the bending moment into a
tension in the guy.

There might also be some weird dynamic/vibration effects that you'd need to
take into account.

There's also the possibility (suggested by Rick Karlquist) that the guy
serves merely as a "collapse restraint" to keep it from falling in a
particular direction, in which case the guy is no different than a piece of
coax hanging from the tower.

>
> For the purpose of illustration, it might be reasonable to take a
> parameter to the the extreme, to see where the fault line is. For
> the life of me, I can't imagine what it is.
>
> Steve K8LX
> _______________________________________________
>
> See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
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