Hank,
You talked about how far in ground and how much above and how much concrete.
What I would like to hear additional about is the sizes of the "dead arms"
that you considered sufficient.
Pipe? 3" maybe or 2" maybe but what is recommended thickness of the walls
of the pipe.
Steel I beams? I have put up 2 Rohn 45's that are 135' in air each. I used
I beams that were in ground 5' and stick above the ground 10'. I have 2
yards of concrete on each of them. They are not back guyed (at this point).
But my biggest worry is did I get I beams that were big enough. Well the
ones I got I think are plenty strong but as I prepare to put up another with
increased price of steel I am wondering what smallest safe size would be.
My current ones are 6" across the sides and 4" across the web and it is I
believe 1/4" thick all around. It weighed like 330 lbs each.
So my general question for both pipe and I beam is what is commonly known as
the smalled "safe" size?
thanks terry
----- Original Message -----
From: <kr7x@comcast.net>
To: <garyejones@cmaaccess.com>; <towertalk@contesting.com>
Sent: Thursday, October 21, 2004 9:44 AM
Subject: Re: [TowerTalk] elevated anchor guy points
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.
_______________________________________________
TowerTalk mailing list
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http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
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.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
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