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## [TowerTalk] guy rod angle

 To: [TowerTalk] guy rod angle mikerauh@ic.org (Michael Rauh) Wed, 05 Sep 2001 22:25:30 -0400
 ```Jerry, Stan, Dave, Tom, I agree with Jerry and Stan - the angle is probably not critical. Rohn presents the angle to 0.1 degree in their guyed tower drawings. This seems impossibly precise to me - there is probably way more sag or bow in the guy anchor than that. I also suspect that Dave is correct when he suggests taking the vector sum of the loads on the guys when the tower is at its rated wind load to find the guy rod angle. In thinking about this problem I realized I don't know how to calculate the individual loads on each guy wire. I use a rigid body model for the tower that will give the total load on the guys, but won't tell me how the guys share the load, at least as far as I can see. To figure out the load on each individual guy, I think I will need to consider how the tower deflects under load. Consider a tower with two sets of guys and an antenna on top. I could start by assuming the tower is fixed at the top and the base. I calculate the wind load and how the tower will deflect under that load. Draw a curve, deflection vs. load. Then assume the lower guy is attached at mid-point, draw a curve of elongation vs. load. The load on the second guy is where the curves meet. The reminder of the load on the tower, including the antenna load, is absorbed by the top guy. But wait! The top guy elongates under load too, relieving the load on the bottom guy. So I will have to set up a system of simultaneous equations in order to get the loads on each guy. I will need equations for the elongation of the top guy, the bottom guy, the deflection (bowing) and the pivoting of the tower. If the tower has a pivot base that is all I need, but if the base is cast in concrete I might need an equation to account for the force needed to tilt the tower as the guys elongate. Does that sound right? Do you know of any references where this kind of problem has been worked out? I know Kurt Andress has found guy loads using a finite element program. I need to understand the principles involved before I resort to a program! I think it would be very cool to know how to find the loads on the individual guy wires in a tower system. Best Regards, Mike Rauh, NV7X Reply to mikerauh@ic.org _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp List Sponsored by AN Wireless: AN Wireless handles Rohn tower systems, Trylon Titan towers, coax, hardline and more. Also check out our self supporting towers up to 96 feet for under \$1500!! http://www.anwireless.com ----- FAQ on WWW: http://www.contesting.com/FAQ/towertalk Submissions: towertalk@contesting.com Administrative requests: towertalk-REQUEST@contesting.com Problems: owner-towertalk@contesting.com ```
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