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[Towertalk] Cracked Leg on Rohn 45G

To: <towertalk@contesting.com>
Subject: [Towertalk] Cracked Leg on Rohn 45G
From: n4kg@juno.com (n4kg@juno.com)
Date: Tue, 8 Oct 2002 13:45:58 -0600
On Mon, 7 Oct 2002 21:34:13 -0400 Bill Coleman <aa4lr@arrl.net> writes:
> On 10/7/02 8:53 AM, n4kg@juno.com at n4kg@juno.com wrote:

SNIP
 
> >The Legs are braced so they cannot move out or in (N4KG)
> 
> Are they? It is hard to tell from the description. What PE did the 
> calculations on the 3 foot pieces of angle iron pounded into the 
> ground?  

No PE.  The pieces of angle iron are painted and much thicker
than a tower leg.  N4KG

> Will they have sufficient strength to hold against all lateral 
> loads?

What lateral loads?  The tower is guyed at 20, 40, 60, 75 ft.
with torgue arms at 40 and 75 ft. Are you saying that the
guys do not resolve all the horizontal forces into a vertical load?

I'm not worried about the small wind load presented by the 
bottom 20 ft of tower. (~4 square ft times 30 psf at 86.6 mph
is 120 lbs divided between the base and first guys).  N4KG
 
> What happens over the next decade or so as they are subject to the 
> corrosive effects of the soil?
 
This was intended to be a temporary solution until I could
replace the tower.  A little valve problem (and replacement
surgery this summer) has delayed my Tower maintenance
projects :-(

> >The space between ground and the next steps is filled
> >with H braces at right angles to each other.
> 
> Is the bracing sufficient to prevent twisting or lateral movement at 
> all conceivable loads? 

I hope so.  The tower FEELS rigid when I manually try to
twist it.   I can't "conceive" of any *significant* lateral forces
at the base of a guyed tower.  Obviously you have some
concern over this issue.  Where would you expect these
forces to come from?

We've had several incidents of strong straight force winds 
over the last 2 years and the tower is still standing so I 
*assume* it was strong enough to withstand the twisting forces.   
N4KG

BIG  SNIP

> Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@arrl.net
> Quote: "Not within a thousand years will man ever fly!"
>             -- Wilbur Wright, 1901


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