Re: [TowerTalk] Broken Rohn 25G Base Section

[Tony King - W4ZT <towertalk@w4zt.com>]

At 01:04 PM 7/7/2004, Melvin Brafford wrote:
> On May 21 a storm took down my 100' Rohn 25G. <snip> The swaged ends are 
> gone, and all I have left is the 3 legs which appear to be ok, and the 2 
> remaining cross and Z brace sets seem ok. I wonder if anyone would trust 
> using the remaining base section stub, and if so how would you attach the 
> next section above it? <snip>

Melvin,

A friend of mine had a tower come down almost exactly the same way.  His 
solution was to cut off the stubs evenly, that is to say level, and then he 
obtained thick walled galvanized water pipe that would just fit inside the 
stubs.  He chose a length that would extend all the way to the bottom of 
the base and six to eight inches above the cut point.  He drilled holes in 
the tubs and bolted the stubs to the pipe with the same 5/16 and 1/4 inch 
bolts the tower uses. He then drilled the protruding ends of the pipe to 
match the holes in the bottom end of the tower section so it could be put 
in place and bolted as normal. He then sprayed the junction with a generous 
coat of cold galvanizing paint. This system worked for him.

Being a certified welder, I wouldn't recommend welding things to the stubs 
(or any galvanized tower sections) for three reasons. The first is that it 
is galvanized and to weld it you should grind off the zinc material before 
welding. Otherwise it generates potentially dangerous fumes. Second, if you 
grind and weld on the stubs, you've created a real potential rust problem. 
Third, the welding process could significantly weaken the structure you're 
trying to maintain.

Using the inserted pipe scheme is the least amount of work and expense and 
will certainly keep the base from kicking out.  Be sure to use temporary 
guys on the first sections (I would stand two sections bolted together on 
the stubs) to insure you aren't depending on the base for safety of life. 
Two men can easily stand two sections up and sit them on the stubs.

Good luck with your project!

73,
Tony W4ZT


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