Joe:
I find it amazing that you can determine the soil bearing capacity at
the guy's site without any test or default basis.
Based on the worst case UBC soil lateral bearing and isolated post
capacity equation; using a 3' hole 4' deep filled with concrete and
casting in a Steel member that is 6' above ground I get a capacity of
about 1000 pounds horizontal and say 1000 pounds vertical which equates
to a total guy capacity, assuming 45 degrees, of about 1400 pounds. This
would be the safe total load on your eyeball system given no available
soils information. This value is base on table 18-I-A in the 1997
Uniform Building Code. Your mileage will vary depending on what code you
use.
It is quite possible that the total guy load on a 70 ' tower will exceed
this amount. Most likely if two or more guys are attached to the
elevated guy post.
The weak link is not the steel member but the soil's ability to
withstand the load you are hoping it will resist.
Hank Lonberg, S.E.,P.E.
KR7X
-----Original Message-----
From: towertalk-admin@contesting.com
[mailto:towertalk-admin@contesting.com] On Behalf Of Joe
Sent: Tuesday, June 25, 2002 7:56 PM
To: K7LXC@aol.com; jperalta@tampabay.rr.com; towertalk@contesting.com
Subject: Re: [Towertalk] Raised Guy Stays
At 03:53 6/26/02, K7LXC@aol.com wrote:
>In a message dated 6/25/02 4:22:43 PM Pacific Daylight Time,
>jperalta@tampabay.rr.com writes:
>
> > I'm getting ready to extend the height of a 30' Rohn 25 bracketed
tower to
> > about 70' and I would like to use raised guy stays ( I think that
is what
> > they are called ) to get the guy wires above head height.
> The best material is I-beam (eye-beam, H-beam). It's much stronger
than
>round elevated guys.
>
> Put 60% of the guy in the ground and 40% above the ground and
you'll be
>in good shape.
I-beams are the way to go. But let's see here, guy wires above head
height
= say 6 feet. Therefore 40% of x = 6 feet. If I recall my algebra
correctly
x would = 15 feet. Which would equate to 9 feet in the ground? I think
this
is a bit much for any 70 foot tower. Put the i-beam in the ground 4 foot
with rebar and Johnson studs with concrete and it will hold anything you
want to put up. A 10 foot i-beam is plenty.
Joe - WL7E/W7
>
>Cheers,
>Steve K7LXC
>TOWER TECH
>
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