[TowerTalk] concrete bases for freestanding towers

[Gary Slagel]

Three years ago I put up a 15 year old used triex wt51 crankup tower and according to the original manual I needed a 3' x 3' x 6' (2 yards of concrete) foundation so that's what I put in.   Two years ago a big storm blew through here and folded the tower over at the middle section.  Pretty obvious that 2 yds of concrete was plenty for that tower!  
 
However, I think its got to make some difference where you're digging the hole.  I'm out here in the Black Hillls of South Dakota and the only way I could dig the hole was with a jack hammer.... that's pretty solid ground surrounding my concrete.  If I'd have been in Nebraska digging through 6' of soft topsoil maybe the 2 yds of concrete wouldn't have held.  So I suppose the specs are written for worst case. 

Gary Slagel
Hot Springs, SD
N0SXX
http://marina.fortunecity.com/sanpedro/351

--- On Fri, 5/13/11, WA8JXM <wa8jxm at gmail.com> wrote:


From: WA8JXM <wa8jxm at gmail.com>
Subject: [TowerTalk] concrete bases for freestanding towers
To: towertalk at contesting.com
Date: Friday, May 13, 2011, 6:18 AM


Many years ago I had a 64' freestanding tower with a 3el triband beam (TA-33) on it.  The base was only 2 cu yards of concrete.  As far as I remember, that was all the manufacturer (Heights) recommended at the time.

Now when I look at anyone's recommendations, the base requirements are much larger.  Rohn (and others) recommends 3 cu yards even for a 40' BX tower.    I had used only 1 cu yard for a freestanding 40' tower.

Is my memory faulty, or have the recommended bases grown over the years?  Were the old recommendations inadequate, or has everyone grown super conservative over the years?   "If one yard is adequate, three will be better, so let's use five yards"???

As one ham commented on the air yesterday, the only failures he has ever heard of were in the tower itself, not the base falling over.  

Ken 
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