David,
I just went through similar engineering with a PE. The PE specified
square tubular construction steel (TS), 7" x 7" x 3/8". Further, of 8.5
feet, 5' above grade, 1' in grade, 2 1/2' in concrete. The concrete is
5' x 5' x 5', the top of which is 1' below grade. #4 rebar is used 12"
on center, each way.
As to connection to the TS, the PE specified a plate through the top of
the TS, in a slit. The plate is 12" x 12" x 1/2". A 1" round bar is
welded to the plate, at least 4". A guy equalizer plate is welded to the
other end of the round bar.
Remember, you must have something attached and protruding to the bottom
of the TS for the concrete to adhere. In my case, 8 each 1/2" x 6"
protrusions, welded to the TS. The are called "Nelsons" or "H.A.S."
You might want to consult a local PE for more detail and to be safe.
Remember, the type of earth in your area may vary thereby altering the
requirements.
Gerry, W6TER
DavidC wrote:
>
> Progress at last! The trees have come down, the area is
> being cleared, tower-time approaches!
>
> One of the three guy anchor points encroaches upon the yard.
> I want to use a raised guy anchor at that point.
>
> My tower is a 60 foot Rohn 45 and if I have understood the
> Rohn manual the guy points are 48 feet out from the base
> and 85 feet apart around the perimeter.
>
> Higher-math is one of my many weaknesses. If I raise a guy
> point to 7 feet how much less than 48 feet is that guy point
> from the tower base, please?
>
> I haven't yet found a local construction-site-surplus-source for
> I-beams but when I do how much longer than the 7 feet above
> ground does the beam need to be? I was guessing that I need
> a 10 foot piece so that I may put 3 feet in concrete. Any
> additional advice as to setting the beam properly is appreciated.
>
> Also, for cosmetic reasons I am thinking of sliding a piece of
> PVC over the I-beam and filling it with concrete. Is this an OK
> idea or do folks have better suggestions? Here in central
> Florida the wood options are limited due to termites and a
> hollow PVC tube makes too friendly of a home for beasties.
>
> Finally, does the I-beam come with attachment holes or
> will I need to find someone who can drill one? Or is there
> another way to attach the guy to it? (I am using Phillystran
> and the yard will be well fenced. Vandalism is unlikely and
> the grass is very short so fire isn't an issue either.)
>
> Thanks! & 73, DavidC K1YP
>
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