Hi Mike,
Not to try to give any specific advice beyond "go seek out a PE",
I just went through this exercise (using a PE) for elevated
guying of 70 feet of Rohn 55 with a 30 sq foot wind load at the
top. To give you an idea of the order of magnitude of the
problem (at least for my local fairly stable rocky soil
conditions), he ended up specifying a 3 foot diameter 6 foot deep
j-bolt in reinforced concrete base (like used for signs and
street lighting poles). And the round steel tubing for the
elevated support needed to be 8 inch diameter material. This was
for a guypoint elevation of 7 feet above grade. I live in an
area rated as a 70 MPH (lowest in US I believe) windspeed zone.
Bear in mind that the guy anchor base must withstand a much
larger overturning moment than the tower base. After all, the
tower is guyed. It's overturning moment should be quite small.
The guys turn this all into vertical load for the tower base.
Do yourself a favor. Let a PE figure this one out for you.
73, Eric N7CL
To: <towertalk@contesting.com>
>Date: Sat, 10 Apr 1999 23:47:37 -0700
>From: "Mike Nash, ND6A" <no6x@inreach.com>
>
>I am wanting to use elevated guy anchors in my installation of
>some Rohn 45. (70 ft). First question: What has been used
>succesfully and unsuccessfully by Towertalkians?
>
Snip... Remaining questions already answered adequately by
others.
>
>Mike...ND6A (ex NO6X)
>
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