----- Original Message -----
From: "R. Kevin Stover" <rkstover@mchsi.com>
To: "Steve Maki" <steve@oakcom.com>
Cc: "towertalk" <towertalk@contesting.com>
Sent: Sunday, April 10, 2005 10:55 AM
Subject: Re: [TowerTalk] Guying a self-supporting tower - Yes
This has been an interesting discussion.
One question comes to mind though.
If you've got the room to properly guy a self supporting tower, meaning
80% of total height, why wouldn't you go ahead and install regular
R25/45/55 or the like?
Seems to me that self supporting towers are used when you lack the room
necessary to properly guy, aesthetics, etc....
>>> Perhaps you don't want to have to trip over guy wires? But, this is
basically an aesthetic question, not an engineering one. For the case you
cite, you'd make the decision based on factors other than safety (i.e.
they're both safe as designed, and presumably with comparable margins).
Maybe you (or your sig other) prefers the look of a 2 ft diameter self
supporter rather than a 1 ft diameter guyed tower with guys sticking out?
Maybe you've got some icing concerns... I'd guess that if you wanted
heights over 100 ft, self supporters start to get impractically big.
(although, think of HV transmission line towers...)
Also, so far the examples used are for round members like the US Tower
or Tashjian crankups. How would guying affect towers like AN Wireless or
Trylon who used folded steel legs and cross members?
>> The form of the tower is not of fundamental importance. What's important
is the strength and the stiffness, and to a second order, the cross mode
coupling (bending moments turning into torsion displacements, for instance).
Whether it's a lattice or a tube doesn't change the fundamentals.
_______________________________________________
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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