[Elecraft] OT: Ground rods and concrete

[tposey@nettally.com tposey@nettally.com]

I expect that the Moderator will be ending this Off Top 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 thought is provable.

In the meantime, I do not include Ufer ground rods in any tower foundation designs that I have professional responsibility.