[TowerTalk] How Important is a Straight Tower?

[Steve Maki]

Pete Smith <n4zr@contesting.com> wrote:

>For the last several years, my Rohn 25G tower has been perfectly happy with
>what I'd estimate is a 2-3" bend toward one top guy (up through the middle
>guy seems pretty straight to me).  I haven't changed anything because it
>would have involved replacing a big grip on that side, but in the process
>of worrying the issue it occurs to me to ask just how important
>super-straightness really is.
>
>After all, a guyed tower is dynamically balanced -- it is flexible enough
>that it adjusts any differences in guy length so that the tension on all 3
>guys at a level remains the same, or nearly so.  That said, as long as the
>bend isn't really severe, does it matter?  Is the strength of the structure
>measurably impaired?
>
>Any of you engineers want to take that one?

It would seem that the lower (to the ground) the bend is, the more
the tower gets derated due to one or two legs carrying more of the
load than they should.

Your case doesn't seem like it should be a problem, except that it
would nag at me until I fixed it.

It WOULD be interesting to find out how much extra compression
occurs in the compressed leg(s), because it is probably more than
one might think - the tension in the opposite leg(s) might have
a multiplying, lever type effect on the compressed side.

I'm obviously not an engineer :)

Regards,

--
Steve K8LX

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