Hi Hans -
I've enjoyed seeing the results of your calculations. As a matter of
curiosity, have you been taking into account column loading, or is that
generally out of the picture? Certainly with an unguyed tower it would be
less than with the same tower guyed. Then, if guyed, there is the tradeoff
between guy weight and angle, and the vertical force component/column
loading obtained from getting to the necesary guy tension/horizontal
restraining force component.
Gene / W2LU
----- Original Message -----
From: <HansLG@aol.com>
To: <towertalk@contesting.com>
Sent: Monday, October 10, 2011 3:03 PM
Subject: [TowerTalk] Fwd: Fwd: Fwd: Maximum Guy Radius
>
> Hi Bill,
>
> I just calculated the torque on the tower element and compared them with
> manufacturer recommended maximum torque. I found a small difference
> between a
> stiff ground mounting and flexible ground mounting. I also tested
> different locations of the guy wire attachment and selected the "best"
> point.
> That's why the guy wires are attached 16 feet from the top. I did not
> make any
> calculations of stress on the individual legs (which I probably should
> have
> done to know for sure everything is within limits) but reasoned that; as
> the tower is suppose to be self-supporting it should be better with guy
> wires. As I have the guys anchors at the 100% point I am not concerned
> that
> things will go wrong. Better: If it goes wrong it will be regardless what
> I
> tried.
>
> You are right though, the stress on the tower legs is critical as it is
> what makes the tower stand.
>
> Hans - N2JFS
>
> In a message dated 10/7/2011 6:45:24 P.M. Eastern Daylight Time,
> baycock2@centurytel.net writes:
>
> Hans--
> I wondered, because I'd always heard that Tower leg compressive stresses
> were a critical factor. Did you monitor them?
> My tower has four guys, but mostly for access and stability rather than
> stress. (It is a folding unit) It is interesting to follow the tower leg
> forces and the Guy stress as the wind direction is rotated from the
> "between
> leg" direction to the "In Line" direction for different numbers of
> anchors.
> Bill--W4BSG
>
> On 10/6/2011 7:54 PM, _HansLG@aol.com_ (mailto:HansLG@aol.com) wrote:
>
>
> Hi Bill,
>
>
>
> With"stiffness" I mean how much the tower will move for a specific wind
>
> pressure. In my calculations I assumed that the tower moved 1" for a give
>
> wind. Then I calculated how much the tower moved for the same wind force
> with
>
> different guy anchor point. I found that minimum move was for an anchor
>
> distance of ~142%. (probably sqr(2)) under the assumption of no guy wire
> sag
>
> (which is impossible).
>
>
>
> I was just "playing around" with a spread sheet and was interested to see
>
> where the optimum point was. 0% anchor point is no good for obvious reason
>
> but an anchor point very far away is not good either as the guy wire is
>
> springy and a too long wire will allow the tower to sway in the wind.
>
>
>
>
>
>
>
>
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