Galvanized steel corrosion on utility poles

[davem116]

I work for a power company in Iowa and 5 years ago we converted to using steel pole in place of wood. We had to remove 3 of the first ones we installed and to our dismay we found that they are rusting at a high rate. The poles are treated with a factory undercoating material from 1 ft above grade to 3 ft below grade with the remaining 3-6 ft ( depending on the hight of the pole)in direct contact with the selected backfill. We used lime gravel to help lower the ph of the soil to extend the pole life. We also added a ground rod one per pole for added lightning protection. On the poles with the copper ground rods there is more rust on the poles but the rods look fine. On the poles that the galvanized rods were used there is some rust on the pole but the rod is almost all ate away. The farther down the pole or rod the worst the corrosion gets. And there was one pole with no groung rod and it was bye far the worst of any. Any Ideas???

 

[Metalguy]

Stop trying to rely on galvanizing to protect steel in such an environment. Coat the galv. areas with a "good" epoxy-something meant for rebar protection should work well.

Then you can add sacrificial anodes of Zn or Mg, and set up a program to monitor and change them.