[Top] [All Lists]

[TowerTalk] Guying Designs

To: <>
Subject: [TowerTalk] Guying Designs
From: (Jim Idelson)
Date: Mon, 29 Mar 1999 18:44:01 -0500
Regarding the following message:

>>I am musing over a sketch of a guyed tower, plan view, and wonder
how the positioning of guy anchor points changes with sloped ground.  Does
one try to keep constant angle by all guys to the tower, by changing the anchor
radius, or do you keep a constant distance to the anchor point, with the
resulting different vertical angles?  Also, if the ground rises a
significant amount on one side, then for a 2 level guy system, the top
guy, and the middle  guy, assuming they would converge to a single point
anchor, on level ground, intesect the real world sloping
ground at two points that have significant spacing between them.  In this
instance, with  sloped ground, do you anchor the top and middle guys at 2 
If the angles of different guys at, say, the center guy point on the
tower, are different, and the guys are tensioned equally, there will be
different horizontal and vertical force components attributable to each
guy.....How do you deal with sloped ground when guying?

K1IR: I believe that your objective will be to create a horizontal RESULTANT 
FORCE at the
attachment point on the tower for each guy which is equal to the RESULTANT 
created when using the recommended anchor point. You will first decide on a 
for your anchor on the ground. This point will be plus/minus in elevation and 
from the recommended standard location. Next, you will use your trig to 
the horizontal components of force at each attachment point when the
anchor is at the recommended position. The inputs to your calculation are the 
standard angles and guy tension. You will solve for new guy wire tensions
using your proposed angles from the ground and the required horizontal force we 
calculated. Finally, you'll calculate the angle that the rod needs to be at as 
it comes out
of the ground. This will be the resultant of the combined guy wire force 
vectors at the
anchor point on the ground.

The result of this will be that guy wires anchored at a lower elevation and the 
same distance
from the tower as in manufacturer's recommended anchor placement will have to be
tighter, and the rod angle will be higher. The wires anchored at this location 
contribute more compressive force on the tower than the other wires. You will 
also need a 
bigger block of concrete in this case, since there is more guy tension.

If you have to put the guy anchor at a lower elevation, it's a good idea to 
move it further
from the tower. This helps you balance the horizontal and compressive forces 
with the other
guy wires.

As you bring the anchor point lower and closer to the base, the horizontal 
forces become 
more and more difficult to control. Until it all falls down.  

Jim K1IR

ps I'm an EE and an MBA, not and ME or a PE! But I think this still makes sense.

The Information Resource for Conferencing Professionals
James S. Idelson
DesigNET International, Inc.
96 Morse Road
Sudbury, Massachusetts USA 01776

tel     978.443.5549
fax     978.443.2034
pager   800.362.0156

FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>