[TowerTalk] guy wire tension

[K7LXC@aol.com]

In a message dated 02/23/2000 4:27:32 PM Pacific Standard Time, 
alwilliams@olywa.net writes:

> Can anyone explain, in more-or-less simple terms, why guy wires need
>  to have such high tension?  Intuitively (yes, I did pass some courses in
>  college physics), if there is no stretching of the guy cable, it would seem
>  that only enough tension is require to keep the guy on a straight line
>  i.e. no slack.

      Ten-percent tension is not "high". For most devices used in a 'working' 
mode (meaning dealing with loads), there is an operating range. In the case 
of cables, ropes, carabiners, slings, etc., it's called the 'safe working 
load'. This SWL is typically in the neighborhood of 10-25% of the ultimate 
breaking strength. This allows the hardware to function safely and reliably 
for a long time under many different conditions. 

     In the case of guy wires, they are tensioned to 10% of their rated 
breaking strength. If the guys are too tight, then there may be excessive 
additional pre-load compression on the tower legs. This obviously has 
potentially fatal implications.

     If the guys are too loose, then wind gusts can cause slack-taut pounding 
of the structure - also potentially fatal. As always, the LXC Prime Directive 
("DO what the manufacturer says") applies.

Cheers,   Steve   K7LXC
Tower Tech  

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