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Re: [TowerTalk] Guying a self-supporter

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Subject: Re: [TowerTalk] Guying a self-supporter
From: "Bill" <>
Date: Thu, 6 Nov 2008 14:46:09 -0800
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The following was Steve's question to me and my response which was snet off the 

Steve said:"Bill,

Are you an engineer? If so, can you devise a case, using a reasonable
tower and guy system, which contradicts my (and others) "theory"? I've 
put this to a few engineers, and they haven't come up with one. I'd be 
the first to shut up about it if an example could be shown...


Steve K8LX"

My response:


Yes I am an engineer but I am not a structural engineer.  But I do know 
enough not to make assumptions  about the consequences of guying a 
self-supporting structure without knowing more about the effect the guying 
has on the buckling mode.  Just saying that you had talked to an engineer 
does not mean anything to me if the engineer is not trained structural 
engineer and I seriously doubt a structural engineer would have passed off 
your scenario so lightly. Such a statement is simply not proof that the 
guying can be done safely.

For example I do know that the buckling mode will depend on the section 
modulus, yield strength, induced compressive stress (when combined with the 
shear stress and bending stress to produce the principle stress) and the 
location of the guys with respect to the length of the guyed sections.  Too 
much stress with too little section modulus  and yield strength over an 
improper length will induce buckling, which is not the same as the simple 
question of the stress at the base and is much more difficult to analyze.

I addition to being an engineer, I was the chief lawyer for CF&I Steel 
Corporation earlier in my career and later the VP and general Counsel of 
SAAB's onshore aviation operation.  I also taught Aviation Law as a 
professor of Flight Technology.  I am very familiar with he issues 
considered by companies that produce towers since CF&I was one of them.  The 
liability to a company for "failure to warn" is one way litigants claim 
liability against manufacturers.  For that reason the warnings have to be 
carefully analyzed and specific.  I was, perhaps, better prepared than most 
lawyers to do that as a design engineer (I helped design parts of the Boeing 
747) so to suggest that the legal position of companies is just something 
the lawyers cook up is pure nonsense.

So it is really up to you to prove that the guying can be done safely and I 
don't think you have even come close.  You apparently have no expertise and 
have not given any credible evidence that anyone with approprite expertise 
has made a considered evaluation of the subject and renedred a professional 
opinion.  Without that the willingness to accept your short-cutted theories 
is foolhardy.



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