[TowerTalk] Tower base/Ufer ground

[Jim Lux]

On 5/16/14, 8:44 AM, Mike Reublin NF4L wrote:
> Thanks Dave. It's a crank-up and has a rebar cage that the tower bolts to.

Then you don't need to do anything special for a Ufer.. the tower bolts 
to the cage which presumably has many feet of rebar in it, and that 
makes the connection to the concrete, which in turn contacts the 
culvert, which in turn contacts the soil surrounding the culvert.

If there happened to be a void between concrete and culvert, the current 
density that point is low enough (since the lightning impulse has 
"spread" from the point of entry at the tower bolt), it won't boil the 
water in the void, so spalling or steam expansion isn't likely.


And dropping $1000 of culvert into the hole is probably cheaper in 
materials and labor than trying to build forms, etc. Especially labor.. 
Same backhoe that digs the hole picks up the culvert from the truck and 
drops it in the hole, then puts the rebar in, and you're done.


Sounds like a great way to solve the "soft soil and water table" thing. 
  You've got a contractor who knows how to do stuff.


>>>> -----Original Message-----
>>>> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Mike
>>>> Reublin NF4L
>>>> Sent: Friday, May 16, 2014 12:39
>>>> To: towertalk reflector
>>>> Subject: [TowerTalk] Tower base/Ufer ground
>>>>
>>>> I have a proposal from a contractor to pour the concrete into  a piece of
>>>> 48" diameter x 12' long piece of steel culvert capped on the bottom end with
>>>> a plywood disc. Very high ground water is the reason.
>>>>
>>>> Will this constitute a Ufer ground?
>>>>
>>>> 73, Mike NF4L