On 11/18/2011 11:33 AM, n8de@thepoint.net wrote:
> I agree with Bill.
> Guys are NOT intended to be used with self-supporting towers, but ...
> can be used with much caution.
I'm not sure where my answer went to this but I'll try again.
One mistake that is so common most take it as being the right way is to
tie the guy to a tower leg. This should not be done.
The guy should tie to a "saddle, or bracket" that fits *around* the
tower so the guys do not put any lateral pressure on the tower legs.
The guy tension will add vertical load to the tower legs just as if you
had put additional weight on the tower at the guy point. This may exceed
the towers dead weight limits.
> The reason the tower may 'sway' with winds after being up so long is,
> as Bill notes, probably due to distortion of the bolt holes due to
> stress.
Most self supporting towers and particularly Aluminum one sway quite a
bit due to the elasticity of the tower itself. They do not need
elongated bolt holes to make them sway, although said holes will
certainly accentuate the swaying and drastically reduce the towers
ability to handle both weight and wind easily reducing the tower's
ratings to a quarter of what it was when new and properly installed.
> You MUST re-tighten all the bolts AT LEAST ONCE per year!
Properly *torque* the bolts.
I am not using a self supporter (100' 45G), but I do check the bolts
regularly. IIRC (this goes back a ways) Other than the first time I
checked them I have never had to retighten those bolts again. I do have
to retension the guys though as I use elevated guy anchors. Even though
they set in 17,000# of concrete (in clay) the anchor posts are very
slowly tilting inward. (about 8" in a bit less than 10 years)
73
Roger (K8RI)
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|