----- Original Message -----
From: "Michael Tope" <W4EF@dellroy.com>
To: "Tom Rauch" <w8ji@contesting.com>; "Jim Lux" <jimlux@earthlink.net>;
"Roger K8RI on Tower" <k8ri-tower@charter.net>; "RICHARD BOYD"
<ke3q@msn.com>; <towertalk@contesting.com>; "Ken Claerbout"
<K4ZW@Staffnet.com>
Cc: <k7nv@contesting.com>
Sent: Sunday, May 01, 2005 9:17 AM
Subject: Re: [TowerTalk] polyrod
>I don't know if Kurt's analysis took this into account, Tom. It would
> interesting to see where the break even point occurs between the
> effect of the catenary in the insulated steel span and effect of the
> higher
> tensile modulus in the composite guy span. I am CC:ing Kurt on
> this message, maybe he can enlighten us.
>
> 73 de Mike, W4EF.......................
>
> ----- Original Message -----
> From: "Tom Rauch" <w8ji@contesting.com>
> Subject: Re: [TowerTalk] polyrod
>
>
>>> If you look at Kurt's tower study (you need to read
>>> down toward the end to see the phylistran case) you
>>> can see that the additional stretchiness of composite
>>> guys can bite you if the base of the guyed tower is
>>> over-constrained (e.g. 3 legged rigid mounting). With
>>> a pier pin, it doesn't matters as the tower just leans a
>>> little more in the wind when the composite guys are
>>> used.
>>
>> With all the insulators and LONG guy lines on my towers the
>> guy sag is so deep the towers move a heck of a lot more than
>> towers I've had with Phylistran guys. You can shake 'em and
>> clearly feel the difference.
>>
>> 73 Tom
>>
Hi,
The guys on the models presented on my website were single element straight
line pinned elements and the analysis was done with a linear FEA engine.
I did not attempt to model the guys as catenary cables as it
was just way too much work, and I knew the linear analysis would not really
process them properly. Things that have a high degree of non-linearity need
to be analyzed with non-linear software.
I hear some pro non-linear FEA software has special elements for catenary
members.
I think Tom's (W8JI) observations are correct as his shaking of the tower is
at low cable load levels where the cable can be straightened under
load most easily.
Probably need to climb the tower in sustained limit load winds and shake the
tower again to make observations about what is happening at the higher load
end of the spectrum.
Now, those might be some pretty exciting reports!
The main reason I ran off and wasted a TON of my time
taking a rudimentary look at this stuff and making it available, was because
too many people posting on the reflector, circa 1998-1999, were stating
that "Since, guys don't elongate........yadyada".
My website states that I don't necessarily know what I'm doing either and
everything there is just a suggestion.
I'm sure the next guy to give this stuff a whack and publish it on the
internet will do it much better.....
73, Kurt
_______________________________________________
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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