N4KG comments interspersed in text -
On Thu, 06 Aug 1998 02:25:33 -0700 Kurt Andress
>ni6w@yagistress.minden.nv.us> writes:
>
>Forgot to say a few things that may help a few fellows. For guyed
towers,
>My analyses have found that when the wind blows * in line* with a set
of
>guys, the guy line loads are maximized and the tower bending loads are
>minimized.
Most of us are now in agreement that maximum GUY
tension occurs when the wind is PERPENDICULAR to
one of the guys in a 3-way system, which is at 30 degrees
to the primary load bearing GUY. de N4KG
The TOWER load appears to be minimized when the wind
is IN LINE with a guy as stated. de N4KG
>When the wind blows exactly between two sets of guys, the guy loads
>are at their lowest value, and the tower bending loads are at their
>highest value. This is caused by geometry completely!
I still disagree with the first part of this statement. When
the wind bisects two guys spaced 120 degrees, the GUY
tension should be EXACTLY EQUAL to the tension in
a single guy when the wind is IN LINE with that guy.
This results from the simple relationships in a 30-60-90
degree triangle where the forces along the short leg are
1/2 the forces along the hypotenuse. These TWO cases
represent the lowest GUY tension conditions. de N4KG
Assuming EQUAL tension in two guys when the wind
bisects those legs, AND that this tension is equal to
the tension in a single guy when the wind is in line
with that guy, the TOWER load from the bisecting
case will be TWICE that of the IN LINE case since
there are now TWO guys with equal tension pulling
down on the tower. This results in the maximum
additional load on the TOWER. (Pretension loads
not included in this analysis, only the additional load
due to wind). de N4KG
Apology to Kurt, NI6W and the group.
Some have taken my original reply to Kurt as a personal attack.
My intent was to question the conclusions and methods which
lead to those conclusions. I certainly meant no offense to Kurt
personally. I can see where my wording left something to be
desired and for that I apologize to Kurt and the group.
This is a perfect example of what can happen when one does
not proof read, mull over, and edit one's response. I usually
do in fact re-read and edit most of my posts before sending.
In this case, I hurriedly posted a reply while getting ready for
work and sent it off. I will endeavor to be more careful!
de Tom N4KG
_____________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|