[TowerTalk] Temporary Guys

[Al Kozakiewicz]

-----Original Message-----
From: towertalk-bounces at contesting.com [mailto:towertalk-bounces at contesting.com] On Behalf Of Donald Chester
Sent: Monday, April 04, 2011 12:20 AM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Temporary Guys


>Another must to avoid is tensioning the guys to maximum during hot weather, since they contract during extreme cold, resulting in over-tension during sub-freezing periods in winter.


I've never erected a guyed tower, but I was curious about the engineering behind that.  The thermal coefficient of expansion of steel is 0.00000645 in/in/def F.  Calculating for 115' of guy wires, I come up with a change of 0.8901" for a 100 degree F swing in temperature.

That might be a lot, but the tower (90' - I thought I read here recently that a 90' tower needs a 115' guy at the top) also shinks 0.6966" for the same swing in temperature.  Without doing the trigonometry, that's something less than a quarter inch in total added "tension".

Like I said, I have no personal experience, but that doesn't sound like a lot to me.  Am I wrong?

Al
AB2ZY