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Re: [TowerTalk] Rohn Torque Bar confusion

To: David Robbins K1TTT <k1ttt@arrl.net>
Subject: Re: [TowerTalk] Rohn Torque Bar confusion
From: Don Havlicek <n8de@thepoint.net>
Reply-to: n8de@thepoint.net
Date: Tue, 03 Aug 2004 15:47:03 -0500
List-post: <mailto:towertalk@contesting.com>
I may be incorrect, but I am under the impression that, when using 'torque bars', the guy anchors are placed in a position that makes the tower face towards the anchor point. This allows double guys from each anchor point to TWO torque bar 'ends'.
When NOT using them, the guy anchor points align WITH the "corners" of the tower.
Don
N8DE


David Robbins K1TTT wrote:


When you translate the plane triangle section in rotation in its

plane,


twist or torque load, initally the guys cannot resist the lateral
displacement as the guy's line of action is perpendicular to theaction
direction of the load. As the triangular section twists additionally

then


there is created an angle between the line of force and the guy line

of


action which can develop a vector resistance to the movement of the
triangular section. This value of resistance is a function of the sine

of


the angle created. It wil start at 0 degrees at rest, sine of 0

degrees


is 0.

This explains why the torsional resistance of the standard guying

scheme


is so low and why if significant torsional forces are present in a

tower


they twist.

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.



but the farther away the attachment point is from the center of rotation
the bigger the angle on the guy wire so the higher the resistance to the
twist.  Granted at 0 there is no force so it won't help with very small
movements but adding rigidly clamped arms that approximately double the
radius of rotation should increase the resistance proportionally.  Also
increasing the radius to where the reaction force is applied increases
the length of the arm applying the force also increasing the reaction
torque applied by the guy wires.


David Robbins K1TTT e-mail: mailto:k1ttt@arrl.net web: http://www.k1ttt.net AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net


_______________________________________________


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_______________________________________________

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.

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