[TowerTalk] Galvanic Protection of Guy Anchors

[Byron Tatum]

Concerning this -- I started doing this with new installations of concrete guy anchor rods -- by first spraying the hot dipped galvanized anchor rods with several coats of 95%, or greater, zinc cold galvanize paint. Next I coat them with a nice heavy coat of roofing tar (1 gallon cans from Lowe's or Home Depot). I use disposable latex gloves and coat the tar on liberally by hand. I coat the rod with this roofing tar just a little past the point of where the top of concrete will be; in other words where just where the end of the tarred portion will be inside the concrete. I stop the tarring on top end of rod about 6" below the welded turnbuckle fan plate. I allow the tar several days to "dry" but it will never get hard except on surface; I go ahead and use a wide electrical tape using 50% overlap wraps and tape over the tarred portion starting at the top of rod (turnbuckle plate end). I stop taping about a foot or so before I get to the end of tarred area that will be in concrete; in other words the taped area will not be in concrete. The main purpose of the tape is to protect the tarring from being damaged/distorted when handling the rod to get it in place in anchor assembly. Unless you have a lot of room (means extra wide slot/trench for rod to traverse from surface to anchor rebar cage) I find it much easier to tar/tape while anchor rod is on sawhorses. The tape also keeps the tar from getting all over your hands/gloves. After the anchor assembly has been poured, cured and I am getting ready to backfill holes I do this one last thing -- I buy enough of the "black poly tubing" to have pieces about 3' long or so for each anchor rod. In my case the rods were 1-1/4" OD. The poly tubing I used was very slightly over 1-1/4" ID; it was marked "1-1/4" on part #. This stuff was at my local lumber yard and was only 85 cents per foot and comes in large rolls (coils); I believe it is for underground water supplies to around 100 PSI. It has a wall thickness of around 1/8" and is very tough. I used a jigsaw and cut the 3' long piece lengthwise. Next I spread it apart (not easy) and used some 3/4" wide small wood pieces to hold open the slot. I placed the opened-up end of tubing piece over the rod and slid the spacers along slot until full length of tubing piece was over the rod. I have about half the tubing in the ground and half above the ground. This protects rods from abrasion, etc. The gap in the poly just almost completely closed when compressed with a heavy duty tie wrap about every 4". Possibly someone has a better way to do this. I have not been doing it this way long enough to have a 20 or 30 year test period to verify the effectiveness of it in slowing down the loss of zinc coating. One comment I do have is that I believe if you have insulated guys, or steel guys broken up with insulators, that the galvanic corrosion of your rods will be less aggressive than straight steel guys going to grounded steel tower.   Byron W5FH