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Re: [TowerTalk] Square Hole or Round Hole for Self Supporter?

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Square Hole or Round Hole for Self Supporter?
From: jimlux <jimlux@earthlink.net>
Date: Sun, 21 Jan 2018 06:25:55 -0800
List-post: <mailto:towertalk@contesting.com>
On 1/20/18 7:19 PM, john@kk9a.com wrote:
I have round concrete bases on my all of my towers however they have guys
and pier pin bases so there is no torque on the concrete. With a free
standing tower there is torque, I guess you're saying that the ground
friction of a round section of concrete is sufficient to prevent the tower
from rotating?


Plenty, I would think. When you think of the rotation torque on a stoplight with a arm cantilevered out over 4 lanes of traffic, and a 60 mi/hr wind blowing on it, that's a lot more than any ham tower is ever going to see. I don't know what the design wind speed is in our area for that kind of thing, but I'll bet it's fairly high, since we *observe* 60 mi/hr gusts regularly during Santa Ana conditions.




John KK9A


From:   jimlux <jimlux@earthlink.net>
Date:   Sat, 20 Jan 2018 14:59:00 -0800



Nope.. Here in Southern California, there's a big business in drilling holes
to be used as foundations for things like traffic lights (huge bending
moment) - you can drill a 4 foot diameter 20 foot deep hole where the
sidewalk is, lower a rebar cage in, and fill it with concrete to make a very
solid pier for the traffic light to bolt to.

The whole "cube" is mostly because it's easy to dig by hand/backhoe, and
easy to calculate.

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