[Elecraft] OT: Ground rods and concrete

[riese-k3djc at juno.com]

I sure hope so

Bob K3DJC

On Tue, 18 Apr 2017 18:10:48 -0400 "Terry Posey" <tposey at nettally.com>
writes:
> I expect that the Moderator will be ending this Off Topic soon.  
> 
> However:
> 
> One of my clients operates a large 90 tower (all self-supported) 
> microwave
> system here in Florida.  Florida is often regarded as the lightning 
> capital
> of the world.  I have helped my client with repairing damaged 
> (cracked)
> tower foundations.  Approximately $1 Million have been spent over 
> the last
> five years repairing concrete foundations that have embedded Ufer 
> rods in
> addition to an extensive external grounding system comprised of 
> radials and
> soil driven rods.  No repairs have been needed to any of the tower
> foundations that do not have Ufer embedded rods.
> 
> I have noticed that the damaged foundations cracks seem to appear 
> after 15
> years of service.  This could be evidence of long term repetitive 
> internal
> stresses - perhaps stresses resulting from steam expansion of the 
> concrete's
> internal moisture due to repetitive high energy lightning pulses to 
> the Ufer
> rod.  Of course, none of that thought is easily provable.
> 
> In the meantime, I do not include Ufer ground rods in any tower 
> foundation
> designs that I have professional responsibility.   
> 
> Terry K4RX
> 
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