[TowerTalk] Nonconductive guys

[Barry Kutner]

On 16 Mar 99,, tgstewart@pepco.com <tgstewart@pepco.com> wrote:


> However, compared to Phillystran, which has most of the same concerns, it
> is about 1/3rd the cost for a stronger product.
> 

Another thing to think about is the coefficient of elasticity. That may 
be the wrong term, but what I mean is how much does it stretch for 
a given load.
In a recent calculation posted on his Web site, Kurt, K7NV, showed 
that Rohn towers with the bottom section sunk in concrete, rather 
than pier pinned, get pretty close to the 1.0 safety factor, below the 
bottom set of guys, when using Phillystran. This seems to be related 
to a greater stretch per unit force.  You need to know how much this 
stuff stretches, and not just ultimate tensile strength, before deciding 
whether it is acceptable.
Kurt, correct me if I've run astray here...
73 Barry
--
Barry Kutner, W2UP              Internet: w2up@mindspring.com
Newtown, PA         FRC         alternate: barry@w2up.wells.com

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