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Re: [TowerTalk] R25 towers

To: towertalk@contesting.com
Subject: Re: [TowerTalk] R25 towers
From: Pete Smith <n4zr@contesting.com>
Date: Mon, 10 Nov 2003 14:10:11 -0500
List-post: <mailto:towertalk@contesting.com>

...
http://www.simpsonanchors.com/ has lots of info..figure out what you need, and go buy it.


Just for an example, for one of the products, from the charts there, it looks like 1/2" allthread (A 307 grade C), embedded 4 1/4 or 6 inches is limited by the allthread strength (3750 lbs). Going to A193, Grade B7 all-thread makes the bond the limit at around 4500lbs (the allowable capacity of the bolt is 8080 lbs)

Going to bigger bolts and holes ups the strength a LOT. 1" bolts have allowable loads like 15,000 lbs.

I'm no pro at this stuff, but it seems to me there's an important caveat -- if you're going to climb the tower as it goes up, use temporary guys before you set the permanent ones, because the stresses imposed on those bolts by a large human on the end of 20-30 feet of Rohn 25, unguyed, could cause something to bend or break, and it may not be the bolt itself. This is no more onerous than using a pier pin mount, which might be another way to go.



73, Pete N4ZR The World HF Contest Station Database was updated October 29. 2469 stations are listed -- 29 new and over 100 updated. Are you current? www.pvrc.org/wcsd/wcsdsearch.htm



_______________________________________________

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.

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