Gary:
I have engineered at least a 100 installations you are describing. Using a
Steel W section or some Pipe or Structural tubing if sized correctly does not
need to be back guyed.
The UBC or IBC in Chapter 18 has a formula for cantilever post type
foundations. Just use the one for the situation where the post can move. In
chapter 18 also is a table of allowable soils bearing values for both vertical
and horizontal loads. Make sure you use the column for the allowable horizontal
values. The kicker is what soil type you have but I would use the lowest value,
for "loon poop", to be conservative. An additional kicker is; the required set
backs from your property line for non-permanent structures. Your jurisdiction
should be able to help you out with that one. Typically it is 5' or so unless
it is a fence less than 6' high. I have used this type of system for towers up
to 200' Rohn 65 thru Rohn 25.
Let me know I can e-mail a picture of a typical elevated anchor post just prior
to pouring the concrete base.
Regards
Lonberg Design Group, Ltd.
Hank Lonberg, P.E.,S.E. / KR7X
President
-------------- Original message --------------
> I purchased a house last year as a compromise house that was OK but
> didn't have some things (like more land) that I really wanted but I
> needed to get into a house for a new job in a new city. I still have
> not found the land/house combination, and need to get a tower or two up
> in the air. Main problem is that I have a 50 foot gas pipe line running
> along one edge of the property. If I put up towers here, it would be
> best to locate one or two of the guys along the property line. I have
> done some preliminary exploration and the gas pipeline company may give
> me a few feet of space at the edge of their easement which would let me
> sink an anchor point/points. The problem is they would like to minimize
> the "permanent" stuff over their easement iin case they need to get to
> their pipeline.
>
> What would help would be to elevate the guy points above ground. Five
> or six feet would be reasonable and make them happy.
>
> I have previously used back guyed drill stem buried in concrete to
> anchor some towers, but was never happy with it. Towers always stayed
> up but I just would have liked the additional security. My towers are
> 100 and 120 feet tall sticks of Rohn 45 and I will run some big
> antennas on them (two or three monobanders on each of them).
>
> Does anyone have suggestions on what and how to do elevated guy anchor
> points which will hold the load of the tower? Has anyone had an
> engineer do the calculations for a steel I-Beam buried in concrete or
> steel pipe? I can't use a back guy, so the anchor has to take the
> whole weight of the tower and stay where it belongs. Can anyone tell me
> about their experience, or how to calculate the loads to figure the
> minimum specs needed or is my only answer to spend some money on an
> engineer?
>
> Thanks
>
> 73
>
>
> Gary W5FI
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather
> Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
> and ask for Sherman, W2FLA.
>
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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