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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: Mon, 7 Oct 2002 06:53:47 -0600
And what do you see as the problem?

The Legs are NOT rusted above the break at ground level,
The Legs are braced so they cannot move out or in,
The space between ground and the next steps is filled
with H braces at right angles to each other.

FYI, the tribanders were installed LONG AGO, before the
legs rusted through at / just under the ground, AND, the
tower has been climbed without incident in it's present
condition.

Many people seem to fail to recognize that for a GUYED Tower,
nearly ALL of the forces at the BASE are VERTICAL.  The
Horizontal forces on a Guyed Tower are carried by the GUY WIRES
which converts them to additional vertical forces on the tower.

W1EVT has 19 R25 Towers 140 ft tall sitting on base plates 
supported by cinderblocks to place each base at the same elevation.
There is NO lateral support at the base other than friction on 
the cinderblocks.  These towers have been up for around 40 years
that I know of.  It is NOT necessary for a GUYED Tower to have 
a base rigidly attached to a large mass of concrete.  It only 
needs a base that can support the Vertical Forces from the tower.

Tom  N4KG

On Sun, 6 Oct 2002 Bill Coleman <aa4lr@arrl.net> writes:
> On 10/4/02 9:27 AM, n4kg@juno.com at n4kg@juno.com wrote:
> 
> >N4KG discovered two legs of a TV tower (similar dimensions to
> >R25 but no diagonal bracing) RUSTED through at ground level.
> >Three 3 ft lengths of 2" angle iron were pounded halfway into the 
> >ground to prevent the legs from moving out.  H braces made of 
> >2X6 pressure treated lumber were placed inside the tower legs 
> >at right angles to each other to prevent the legs from moving in.
> >These wooden braces extended up to the next steps which will
> >support the vertical load in case the tower sinks.  This tower is
> >still standing 2 years after discovery of the rusted through legs,
> >supporting 3 tribanders at 40, 60, and 80 ft. with guys every 20 
> ft.
> 
> So, uh, who would climb such a tower to install the tribanders?
> 
> 
> 
> 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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