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## Re: [TowerTalk] Tower Base Round or Square?

 To: "'Towertalk'" Re: [TowerTalk] Tower Base Round or Square? "Mike" Wed, 26 Oct 2011 17:24:25 -0500 mailto:towertalk@contesting.com>
 ```When you place a 45G concrete base plate with the pier pin centered over an 18"radius pier, two corners will overhang. The plate hole is centered with the legs, not centered with the plate ;-)) That's the gotcha... K4EAR -----Original Message----- From: towertalk-bounces@contesting.com [mailto:towertalk-bounces@contesting.com] On Behalf Of Joe Subich, W4TV Sent: Wednesday, October 26, 2011 4:10 PM To: Richard Thorne Cc: Towertalk Subject: Re: [TowerTalk] Tower Base Round or Square? I asked the same question of a well known Professional Engineer a couple of years ago. His answer was quite simple and made a lot of sense ... the round base can be used instead of a square one if the diameter of the round base is the same as the *diagonal* measurement of the square base. In your case, for a 2' 6" (30") square base the round equivalent would be 42" diameter *not* 36" as you propose. The reason has to due with projected surface area - the area that resists overturning - not volume (or weight) of the concrete. 73, ... Joe, W4TV On 10/26/2011 1:28 PM, Richard Thorne wrote: > I'm finally getting some dirt work done in the next day or two at my > new place which will include holes/concrete for my 45g tower. > > I plan on using a pier pin install, so does it matter if the base is > square or round? The rohn book calls for a 2' 6" square hole 4' deep > (I'm designing the tower based on 90mhp winds with a height of 120'). > It would be easier to use a 36" auger to dig the hole. Since I'm > going with a pier pin I don't see that there would be any twisting > moments on the concrete base, it would only be there to hold the tower > up. But I'm not an engineer, hence the question. > > Thanks > > Rich - N5ZC > > > _______________________________________________ > > > > _______________________________________________ > TowerTalk mailing list > TowerTalk@contesting.com > http://lists.contesting.com/mailman/listinfo/towertalk > _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
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