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## Re: [TowerTalk] Rohn Torque Bar confusion

 To: , "Tower (K8RI)" , Re: [TowerTalk] Rohn Torque Bar confusion "Tom Rauch" Tom Rauch Tue, 3 Aug 2004 16:42:26 -0400
 ```displacement is resisted by the guys as the vector summation of the forces in the guys. Equal and opposite total reaction. The tower section is in equilibrium and will not translate in its plane. Remeber guys only resist tension and cannot resist a lateral load to their line of action.>> ....but eventually the tower twists enough that guy tenison tries to pull it back. I KNOW this happens because when moron's improperly install or guy a tower and the anchors are not aligned with the point of the tower, the tower gets all shaky and twisty no matter how tight the guylines are. This is because the tension of the guylines is trying to twist the tower, rather than hold it in position. As the guyline is moved out on torque arm the effective radius of the tower increases, and rotational movement decreases enough that it is VERY easy to feel. It isn't quite true to say guylines don't help keep the tower from turning. Anyone who has climber a tall tower with a point base that allows rotation, like an insulated tower, knows the guylines greatly contribute to rotational stability. When those needless do-nothing torque arms are added, the tower becomes much more stable. The only question I have is if the increase in resistance to twist translates into higher wind survival ratings, or if the tower can "twist" so much without contributing to failure the rating does not change. Of copurse even if the survival remains the same, I still prefer to NOT have my tower twist more than necessary. > In this case the farther away from the center the guy attachment point is really doesn't help with the torsional strength the angle between the guy and the line of force of the torque is what matters. I don't agree. While the angle remains the same, the lever distance from center is increased. If you double that distance, it is a two-fold increase in resistance to twist for the same increase in guyline tension caused by the twist. > When you star guy or 6 point guy a tower with a torque arm mechanism then you have guys that are better aligned to initally resist the twist from the onset. Therefore this type of system is better able to resist torsional loadings. That's certainly true, and you don't need a six point guy. You can use a three guy anchors and split each guyline into two ends some distance from the tower. If you keep the angle small, there is almost no difference at all between six guy points and three. 73 Tom _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA. _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
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