Interesting idea...
It's not so much the failure or bending of the beam you've got to worry
about, it's the ripping the footing out of the ground. Embedding the beam in
concrete 3 or 4 feet is probably OK, but you'd probably need to make the
concrete pad fairly good sized (or deep). You're basically putting a hefty
side load on the top of a 7-8 foot lever arm, which is going to try and pry
the concrete footing out of the soil.
You could approach the problem two ways.
1) Make the footing extend out far enough that its sheer mass counteracts
the force of the lever arm. For instance, if your guy is pulling 1000
pounds at the end of a 8 foot lever arm, and you extend the concrete out 4
feet and it weighs 3000-4000 pounds, then the 8000 lb-ft isn't going to move
the 12-16000 resisting force (assuming that it doesn't settle or move in the
soil). 3000 pounds may sound like a lot, but that's less than a cubic yard
of concrete. (A cubic yard of water weighs about a ton)
2) Drill a long skinny hole and fill it with rebar and concrete attached to
your beam (this looks more like a classic tower footing).
It might be cheaper to buy a longer beam, and drill a smaller diameter hole
to sink it into (the telephone pole approach).
In fact, getting someone to plant some used telephone poles might be an even
better approach. This isn't all that expensive if you find the right folks
doing it. They have the auger and equipment all on one truck, and if you
can make a deal with someone replacing poles (or placing temporary power
poles, e.g. at construction sites), they may be willing to plant the old
poles for the proverbial case of beer. (or, more likely, a reasonable cash
gratuity)
----- Original Message -----
From: "Conrad Nasatka" <conco@paonline.com>
To: <TOWERTALK@contesting.com>
Cc: <Sales@ChampionRadio.com>
Sent: Tuesday, March 02, 2004 7:10 PM
Subject: [TowerTalk] I-beams used as guy-wire anchors!
I have been on this reflector for several months.
Aside from the occasional sidetrack, it is pretty darn knowledgeable.
Having said that...I was wondering if anyone has had experience with using
I-beams to anchor their guy-wires? I have a Rohn 25 G up 60 feet. It has
the two, called for guy positions, one at 28 feet and the other at 55 feet.
Would a 10 foot , W-6 X12 X10 foot handle the load? I would cement it in
the ground 3 or 4 feet. The company says that this I - beam would weigh 120
pounds. Twelve pounds per 1 foot of I-beam. I have never dealt with this
before as I usually run my guy-wires to the ground. This is an unusual
situation because I have been graciously permitted by a neighbor to place
two on his property. An attempt at using 10 foot schedule 80 galvanized
water pipe got me no where, I now seek help using the I-beams so I can get
6 or 7 feet above ground to allow grass mowing. I'd appreciate your
considerations.
Regards
73
Conrad
WB3DQD
----------------------------------------------------------------------------
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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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