[TowerTalk] Guyed towers flexible restrains

[Hank Lonberg]

Mark:

The guys in a guyed tower are actually non-linear. It is
difficult to assign a spring constant to them. 

I model guyed towers in my FEA programs with the guys  as
tension only cables the programs also allow for the catenary
behavior. The analysis is iterative until a lower limit of
error is attained something on the order of  0.01 pounds for
summation of forces in equilibrium.

A ball park number may be say 0.6 of the breaking force with
say 1" of elongation. They are steel so you could use
steel's stress-strains characteristics as long as you are
below the elastic limit. 

The conservative hand calculation assumption of a pinned
support gives a little larger bending moments in the tower
sections  or mast but that falls with the assumption of
pinned supports with no lateral deflection. 


Regards
Lonberg Design Group, Ltd.

H.S. Lonberg, P.E.,S.E. / KR7X
President

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Mark
Foigel
Sent: Sunday, January 28, 2007 11:39 AM
To: towertalk at contesting.com
Subject: [TowerTalk] Guyed towers flexible restrains
Importance: High

Hi,

Computing the mast itself:

What will be the adequate model so to assess rigidity of the
partial
restrains ("spring type"), as normally provided by the guys
in a continuous
beam model assumption for the mast?

Appreciate a lot,

Mark


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