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Re: [TowerTalk] Broken Rohn 25G Base Section

To: "Melvin Brafford" <roadrulz@isp.com>
Subject: Re: [TowerTalk] Broken Rohn 25G Base Section
From: kr7x@comcast.net
Date: Wed, 07 Jul 2004 18:32:35 +0000
List-post: <mailto:towertalk@contesting.com>
Mick:

A possible fix depending on how you are at welding or know someone who is a 
certified welder is to  trim the legs down to say 12" long vertically. Weld 
some channel legs to the stub legs say 8" overlap and have the channel legs end 
about 8" above the stub legs. Weld the legs to the back of the channel sections 
with the channel flanges pointing to the outside..... (weld on both sides of 
the leg to channel lap. You can use stich welding to minimize warpage.

O[  <------  outside

Take a normal tower section and set on top of the stub rohn legs and drill out 
the channel web to match the bolt holes in the tower legs. Bolt up and you have 
created a reinforced splice in the leg. The channel can be C4 or so does not 
have to be real big just a bit larger than the area of the leg in cross 
section. 

This is a suggestion and other splice mechanisms would also work. The load in 
the legs at the base for a guyed tower, even those embedded in concrete is 
mostly axial not in bending. 

Your milage may vary but this should work.

73 

Lonberg Design Group, Ltd.

Hank Lonberg, P.E.,S.E. / KR7X
President




> On May 21 a storm took down my 100' Rohn 25G. All the "big grip" connections, 
> EHS cable, etc held up ok. When an 80' tall tree fell on the SE guy wires, 
> the 
> NW guy anchor pulled up out of the ground, and the tower folded like a 
> hair-pin 
> at the 30' level, and fell toward the direction of the tree(SE). The force 
> exerted on the tower as the tree hit it also, broke one of the tower legs at 
> just above the 2' level. The 25G was pushed and pulled at the same time. I'm 
> left with around 2 feet of tower sticking out of the concrete base. 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? Thanks, and direct dialogue will be fine, so as not to clutter up 
> the 
> reflector.
> 
> 73, Mick  W4YV
> _______________________________________________
> 
> 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.
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________

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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