[TowerTalk] R25 towers

[Pete Smith]

>...
>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
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