This should not be a factor where the Phillystran is used as a truss at
a fraction of its strength. As guy lines the standard "Big Grip is
recommended. They haven't used Spelter sockets and epoxy for some
years even on the larger 6,000# cable.
For a truss 3 saddle clamps are used with the saddle on the live side
(never saddle a dead horse) so creep has never been a problem when used
on a truss. The Big Grips (Recommended by Phillystran and sold by
vendors) grip entirely on the jacket, but it's over about 18" or more.
If you wrote a recent article recommending Spelter sockets, it is not
what the manufacturer recommends, hence they have not been the proper
method of termination for a number of years. I don't know when they
changed, but it was Big Grips in 2002, or 13 years ago when I installed
my 45G using Phillystran's recommendations. I didn't find any sellers
of Phillystran even offering Spelter sockets.
Follow the "Prime Directive"
73
Roger (K8RI)
On 10/21/2015 11:35 PM, Grant Saviers wrote:
I strongly advise against saddle clamps. The problem is creep of the
plastic jacket causes the clamp force to decay with time. Until the
clamp completely cuts through the jacket the clamp force decays. At
room temperature it took about 3 weeks and at least 4 tightenings to
get the saddle to cut through the jacket. I used a torque wrench to
set the tightening force and measured the residual torque at a late
time each cycle. I built a tension tester and verified saddle
terminations will slip well below the breaking strength of the
Philly. Even after 121 days and 4 tightening cycles the saddle clamp
torque values indicated continuing creep and reduced termination
strength. I was unable to achieve more than 30% of the break strength
of the Philly. (25000# Philly and 7000# load for slippage).
Later I tested the proper terminations for this Philly (Spelter
sockets with epoxy) on a commercial 100,000# tension test stand and
the guy failed at 28000# tension and not the termination. See NCJ
Nov-Dec 2014 for my article.
I've seen bent booms as a result of using saddle clamps. I also found
them loose on my steppIR 4L after a year on the 1200 size so will
never use it again.
Phillystran says use grips on all 2100 and larger. Follow the
directions!
Grant KZ1W
On 10/21/2015 13:06 PM, Mike Reublin NF4L wrote:
Mostly what compresses is the jacket. No strength is lost. My SteppIR
uses Phillystran (as a bridle) with small saddle clamps. The PS is
very flat in the clamps.
73, Mike NF4L
On Oct 21, 2015, at 3:46 PM, GMuller885--- via TowerTalk
<towertalk@contesting.com> wrote:
All:
Thank all of you for the input. Based on all the input my
guys and
stays are of Phillystran 6mm dia 2100 lbs break strength. I am
using guy
line clamp kits, three to a connection. The only question left is
that if
the Guy cliompress the Phillystran how much strength is lost if any?
Gerald Muller K9GEM
GMuller885@aol.com
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Roger (K8RI)
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