[TowerTalk] Broken Rohn 25G Base Section

[kr7x at comcast.net]

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
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