A suitable base for Rohn 25G & 45G to replace concrete, is a section of
culvert 6" larger in diameter than the tower section, and set 5 ' in the
The tower section is set in, with a layer of small gravel in the bottom for
drainage, then the space filled with pea gravel and compacted.
Note: This is a suitable base for a guyed tower. I am not a proponent of
feestanding small towers with large amateur loads!
From: Malcolm Clark <firstname.lastname@example.org>
To: Mike <email@example.com>; firstname.lastname@example.org
Date: Tuesday, April 14, 1998 5:49 AM
Subject: Re: [TowerTalk] Now What?
>> The Idea of a 4-5 foot hole with the tower
>> stuck in then 1 1/2 inch rock covering sounds nice.
>> Will it handle the load of say 70 feet of Rohn 25?
>> Or maybe Rohn 45 should be used?
>The maximums for freestanding 25G and 45G are:
>25G 40' 1.5 sfwl @70 mph (2.4 yds concrete)
>45G 45' 2.3 sfwl @70 mph (4.1 yds concrete)
>The base of a freestanding tower has to be imbedded in a solid block
>that is big enough and weighs enough to withstand the maximum
>overturning moment that will be generated by the rated wind speed and
>wind load. Gravel cannot possibly do that.
>With a bracketed tower, it is mainly the bracket that withstands the
>overturning moment--not the base by itself. You really should get a
>Rohn catalog. You can send them ten bucks or you can send Steve five
>bucks. Shouldn't be a hard decision.
>You don't have to use the exact examples in the catalog. Rohn cannot
>possibly cover every situation. But you do have to understand the basic
>physics of your planned installation and design accordingly. You also
>have to check and find out what the zoning ordinances and building codes
>require. You probably will need a building permit for any substantial
>installation--almost certainly if you are located anywhere in suburbia
>or the big city. And I would suggest you get your landlord's blessing
>for anything concreted in or bolted to the house.
>FAQ on WWW: http://www.contesting.com/towertalkfaq.html
>Administrative requests: towertalk-REQUEST@contesting.com
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
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