[TowerTalk] u clamp sizes for phyllistran?

[K8RI]

On 8/30/2012 11:50 AM, K7LXC at aol.com wrote:
>>   I have various pieces op phyllistrad and wish to use it  for boom
> support
> and other purposes.
>
>>   Need to know the  proper size U clamps for:
>
> T1200
> HPTG 2100I
> HPTG 4000I
>
>      As long as your applications are non-mission  critical (something other
> than guy wires), feel free to use clamps that are  appropriate for the OD
> size of the Phillystran. Measure the OD and head to the  hardware store.
>
>      For guy wires, DO NOT use cable clamps on  Phillystran. The Phillystran
> will cold-flow under the cable clamp compression  and it will compromise
> the reliability of the material.


The smaller 2 sizes of Phillystran used for guying do not have "big 
grips" and require that you do use cable clamps.  Remember to use the 
u-bolt on the "dead side" and the clamp will not distort the load 
carrying side drastically.  It's the protective jacket that compresses 
drastically, while the Kevlar core is only compressed a little. Even on 
wire, cable clamps can reduce the load carrying capacity by 50% which is 
why we see a minimum of 2 clamps and usually 3 used in critical load 
bearing areas. Use at least 3 clamps on the Phillystran that requires 
them and tighten them snug, not as tight as you can possible get them.

These sizes are normally used on small towers and boom trusses. I think 
you will find that they do not affect the strength nearly as much as the 
indentations would make us think.  Still, I agree that for normal 
guying, use the sizes that have big grips available.

73

Roger (K8RI)

>
> Cheers & GL,
> Steve      K7LXC
> TOWER TECH -
> Professional tower services for amateurs
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