I wonder if the old idea of using two 20 foot steel beams in an X
configuration anchored to the ground with screw anchors would work.According to
the script each anchor has a pull-up rating of 14,000 pounds. That wold result
in a resulting 280,000 foot-pound torque which might be enough for a decent,
self-supporting tower. I don't know if a buried or above-ground installation
should be best. Buried makes inspection for corrosion damages hard while
above-ground is a trip hazard.
I've never seen it implemented but believe an above-ground installation could
be cheaper (depending on the price of the steel beams) than a buried cement
lump. At least it would require a back-hoe. Just a thought.
Hans - N2JFS
-----Original Message-----
From: jimlux <jimlux@earthlink.net>
To: towertalk <towertalk@contesting.com>
Sent: Mon, 22 Jan 2018 16:22
Subject: Re: [TowerTalk] Square Hole or Round Hole for Self Supporter?
On 1/22/18 12:06 PM, Richard Thorne wrote:> Clay,> > I emailed a fella by the
name of Jeremy. He quoted me $2800 for a 10' > hole.> > From the other post's
on the subject probably a reasonable number. I'll > still research the back hoe
method. I'll bet will be less expensive to > use a back hoe and have the dirt
hauled off (if needed).> generally that's the case. Round piers are handy if
you're already drilling them for some other reason, or if you have limited room
on top (a 20 foot deep 3-4 ft pier will fit a lot of places)There's also other
schemes - shallower and larger in plan, for instance.There have been
discussions on this list a few years ago about a sort of X plan -essentially
radial reinforced concrete beams - you could be pretty shallow, at the cost of
having 10 or 15 foot "arms" sticking out. There are lots of engineering
alternatives - there's nothing "special" about the "cube" as a base.Or, if your
self supporter isn't a "flagpole" and skinny - Tapered to
wers: HV transmission towers, Windmills and Rohn BX have a lot of taper. I
suspect that you don't need a lot of "foundation" under the feet for that -
enough to keep the downwind leg from sinking, and the upwind leg from
lifting.______________________________________________________________________________________________TowerTalk
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