Well you are correct in that it is shown in the consumer catalog and the
chart is dated 1987 and references 222-E. 222-F the latest standard differs
from 222-E. I would not bet on a 40' 25g and ever recommend that a client
use it unguyed. Your mileage may vary.
73
Hank / KR7X
-----Original Message-----
From: Blake Bowers [mailto:bbowers@townsqr.com]
Sent: Saturday, January 29, 2005 2:21 PM
To: Hank Lonberg; TowerTalk@contesting.com
Subject: Re: [TowerTalk] Rohn 25
Page 25G-1, and page 25G-2 of the Rohn consumer catalog.
Their design charts, their design drawings.
> Blake:
> I beg to differ with you.
>
> Using TIA/EIA 222-F wind loading criteria and 70 mph wind velocity (min.
> recommended) a 40 foot section of Rohn, 25g un-guyed and cantilevered will
> develop a moment at the base of 7200 ft-lbs at the base. This is without
> an
> antenna load, just the tower itself. The published allowable moment for
> 25g
> ,by Rohn, with a 1/3 increase for wind loading duration is 6,720 ft-lbs.
> At
> 40 feet it is clearly overstressed. How do you say that this is ok and
> that
> Rohn fully supports this?
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|