[TowerTalk] Fwd: Fwd: Fwd: Screw Anchor Experience

[Steve Maki]

On 6/22/2013 9:35 AM, I wrote:

> According to Anchor Guard, an anchor even all by itself can act as a
> corrosion cell:
>
> "Basic Anchor Support Design Example 1. Figure 6 shows the basic design
> of a typical anchor support. The anchor support has all the necessary
> elements of a corrosion cell. The shaft itself acts as both anode and
> cathode as well as the electrical path between the two. The concrete and
> soil act as dissimilar electrolytes. The soil has less oxygen just above
> the concrete anchorage and consequently, less resistivity. The
> electrical path is the shortest between the anode and the cathode at the
> same point as the oxygen deficient soil, thus the deteriorating action
> of corrosion is most strongly in effect in this area. Experience has
> shown that this is the area most likely to deteriorate and cause the
> tower to fail."

One should note of course that Anchor Guard is in the business of 
selling anchor protection.

But it would seem that a prudent design would include insulation from 
the tower AND total encasement in concrete below ground level.

-Steve K8LX