[TowerTalk] Imagine that!

[Dale Martin]

>
> In a message dated 03/06/2000 10:18:58 PM Pacific Standard Time,
> kg5u@hal-pc.org writes:
>
> > What is the breaking point of 3/16" stainless steel guy wire?
>
>      According to my research if it's stainless steel
> aircraft cable, it's
> 3700 pounds.
> >

What's considered nominal tension for an 80' Rohn 45G tower?  Is 3.7k lbs
sufficient?  Is it marginal?

> >  My Rohn book was no help.  Neither was Rohn when I called
> and asked them.
> >
>      No surprise - they don't use the stuff (they don't build
> aircraft - hi).
>
> >  We did agree that 10% of breaking strength was normal for
> guy tension.
> >
> >  I've posed the questions (what's the breaking strength of
> the guy wire and
> >  what is the tension to which the guys have been drawn?) back to the
> >  electrical Tech Monitor to get that info.  The guys seem
> awfully taut.
> >
>        I'm assuming you used three cable clamps per
> termination with the
> saddles in the right direction.

Yes.  That was one of the first things I looked at when I went out there
Saturday to see what was being done.  The clamps are on correctly on all
guy/turnbuckle eye interfaces.

>How did you measure the
> tension?

I didn't.  They were done sometime Saturday afternoon, so I never got a
chance to find out from them.  I posed the question to their NASA technical
monitor and was hoping to hear from her today.  I'm calling her first thing
in the morning.

>A Loos Guy
> Tensioner should give you a reasonable reading.
>
I'm taking in my Loos gage in the morning and measuring it myself to see how
their numbers (if they provide them) compare.

They did not put thimbles on two sets of guys at the turnbuckles (but they
did put thimbles on the first set of guys they installed.  I pointed that
out to their technical monitor suggesting that maybe they MIGHT be coming
back to finish the job (installing the thimbles).  Also, I noted to myself
and to her that in two cases, one cable clamp on two sets of the 1/4" SS
cable that they used to interface the ground side of the turnbuckle eyes to
the ground anchor were hard against the turnbuckle eye and seemed to be
actually bending the cable a bit.

Where the thimbles are missing aronund the turnbuckle eye, the cable is
splaying.  Certainly doesn't look good.  At least, it doesn't look as good
as the set of guys with the thimbles.

I think the technical monitor needs to come out and take a look for herself
tomorrow morning.

73,
dale, kg5u


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