[TowerTalk] Clamps and Phillystran

[Jim Rhodes]

The ONLY way to terminate 1200# Philly is with clamps & eyes. The larger 
sizes all use grips, but the 1200# states clamps (4) and eye. No grips 
available.


At 06:23 AM 07/31/2000, alsopb wrote:

>Your information is old.  The current "best practice" is to use
>preformed big grips of the "correct size".  Texas towers sells the
>cable and big grips.
>
>Regarding GM use of clamps.  Even their tallest tower (70') only uses
>1200# kevlar (phylistrand) with a preload of 120 pounds. Rohn 25 uses
>4000# phylistrand and 400 pounds preload.  Screw in anchors are used
>as opposed to concrete imbedded ones. The tower base concrete section
>is considerably larger than for Rohn 25 (4'X4'X4' for a 70' tower).
>The aluminium tower has a 16" face for the 50 and 70' designs. It's
>pay me one way or another.  Personally, I like the ease of
>installation (no holes/concrete for the guys) and the skinny, light
>phylistrand guys which disappear into the background.  I also like the
>tower and base absorbing most of the horizontal load.
>
>GM has done studies showing that for their application cable clamps
>are perfectly adequate.
>
>By the way, if you want to be shocked,  cut open the 1200 or 4000#
>phylistrand cables and count the number of Kevlar fibers.  You can do
>it on two hands.
>
>73 de Brian/K3KO
>
>Henry and Kate wrote:
> >
> > All this talk about clamps and Phillystran has me a bit concerned. It was
> > my understanding, based on an information sheet I get with my Phillystran
> > orders, is that the only ways to terminate the stuff is with potted ends
> > (older style) or with Big Grips.
> >
> > Any use of clamps with Phillystran is counter indicated and is dangerous.
> >
> > To comment on clamp application methods, the manufacturer of the clamps
> > will have an application sheet that details the correct orientation,
> > spacing, torque and holding force for the product.
> >
> > Again, it's a case of the "Prime Directive" being applied.
> >
> > end
> >
> > Henry and Kate
> > KB7RTA and KC7GTU
> > kate@rio.com
> >
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Jim Rhodes K0XU
rhodes@willinet.net


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