[TowerTalk] Weak Link in Guy System?

[Tower2sell@aol.com]

In a message dated 11/17/00 6:56:45 PM Central Standard Time, 
ray1965@hotmail.com writes:

>   I am laying out parts for installing Rohn 45 tower 100' high.  Details 
for 
>  90 MPH 100' are 1/4" at 91' and 3/16" at 61' and 31'. From the AnchorData 
a 
>  Rod No. of 303 is given.
>    The 1/4" EHS is rated at 6400# and the 3/16 at 3900# break strength.
>  The Rod 303 allowable load is only 7,330 #.
>  
>    If all three guys are connected to the single Rod, it would seem to be 
>  greatly overloaded.  Yet I have never heard of a Rod breaking, but have 
>  heard of numerous guy wires breaking.  I am puzzled as it, would seem the 
>  Rod would be the week link when connected to the 3 guys.
>    Do I need to go to the 3455 with 17,670 at twice the cost ($57 vs 
>  $110)each or is the 303 safe as Rohn specifies?
>  Ray KB5DO

I really doubt that the larger anchor would be any better. The thing to look 
at is that you are comparing the ultimate gut strength to the allowable 
anchor stregth. The tower can only use 50% of the breaking guy wire stregth 
as an allowable tension. The anchor rod strength inclues a factor of safety.  
A guyed tower, when overloaded, normally fails by collaps of the tower and 
the guy wire staying intact. The tower sort of does a crushed beer can and 
tends to come more or less straight down while the wires kind of keep the 
tower from "falling over" and keeping it in a nice big pile of scap iron. 

A typical guyed ROHN tower will normally fail in the legs or the braces. If I 
was to place a bet on your configuration it would be the diagonal brace just 
above the top guys.

I would put my extra money into protecting the anchor rod from rusting. I 
would rest much easier knowing the anchor rods were intact instead on the odd 
chance that extreme wind conditions might blow the tower over. That's what 
insurance is for. Here is the question -- does insurance cover loss due to 
rust?

Tower2sell@aol.com

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