[Elecraft] OT: Ground rods and concrete

[Terry Posey]

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