To protect your tower investment, we recommend a complete Cathodic Anchor Shaft Protection workover on any tower more than five years old. We have performed Cathodic Anchor Shaft Protection workovers on many of the older guyed towers we service. Of those Cathodic Anchor Shaft Protections, none have failed.
An Cathodic Anchor Shaft Protection workover is a great way to ensure the safety, security and longevity of your guyed tower. When you request an Cathodic Anchor Shaft Protection workover, our trained technicians will:

     
  • Excavate your Cathodic Anchor Shaft Protections down to the concrete anchor block
  • Clean and inspect them
  • Install corrosion protection in the form of high-potential magnesium anodes at each anchor location (to stop the natural corrosion process)
  • Replace Cathodic Anchor Shaft Protections that have endured heavy damage
  • Coat your Cathodic Anchor Shaft Protections with a layer of tar for added protection and to extend the anode's life expectancy

Cathodic Anchor Shaft Protection Workover Process in S.D.		  


Drilled anchor foundation

We will then check the Anodes voltage at each Cathodic Anchor Shaft Protection during our annual tower inspections to make sure they are maintaining a safe (non-corrosive) level.

Cathodic Anchor Shaft Protection FAILURES

1) 1990/ Hazen ND./ 250' tall  2-way tower. Approx 20 years old tower.

2) 1995 / Valley City ND./ 300' tall FM tower. Approx 3 year old tower.

3) 1990 / Langdon ND / 350' tall cable TV tower. Approx 20 year old tower.

4) 1999 / Drake ND / 200' tall NW Bell Tel microwave tower. Approx 20 year old tower.

5) 1991 / Grand Forks ND  Air F. Base./ 500' tall cable TV tower. Approx 20 years old.

6) 1998 / Valley City ND / 300' tall Power Co. microwave tower./ Approx 15 years old.

7) 1988 / Devils Lake ND / 300' tall Cable TV tower / Approx 20 years old.

8) 1988 / Aberdeen SD / 300' tall Power Co. microwave tower/ Approx 30 years old.

9) 1980 / Colfax ND / 300' tall Power Co. tower / Approx 10 years old.

10) 2007 / Grand Forks ND / 180' tall 2-way tower / Approx 7 years old.

11) 2008 / Britton SD / 400' tall Cable TV & Cellular tower/ Approx 20 years old.

12) 2003/Vermillion SD/280' tall cell tower/fell across hiway/approx 12 yrs old.

 #13  Portland, ND, MIDCO 2001 cable TV tower, 180’ tall Rohn model #55 tower.  Single round rod anchor corrosion failed/tower collapse.  (No cathodic protection system)

#14)  1980/Toronto, SD/ Ottertail Power’s 220’ 2-way tower fell

#15) 1995/Toronto, SD/Ottertail Power’s 400’ tower fell

#16  1998/Toronto, SD/Northwestern Energy’s’ 400’ tower fell

Can you afford to loose one of your guyed towers to Cathodic Anchor Shaft Protection corrosion?

Anchor corrosion problem

Britton SD / 400' / Cathodic Anchor Shaft Protection corrosion

GPT web photo/ Cathodic Anchor Shaft Protection in failure 5 years Grand Forks ND area.

2.25" solid rod Cathodic Anchor Shaft Protection with approx 30% cross sectional mass remaining (1.25' OD) after 10 years without corrosion protection 10 miles North of Fargo ND.

Cathodic Anchor Shaft Protection Corrosion Protection


Cathodic Anchor Shaft Protection inspection excavation


Cathodic Anchor Shaft Protection work over plus GPT-2 system installation

GPT-2 Cathodic Anchor Shaft Protection corrosion control installation photo

GPT-2 Cathodic Anchor Shaft Protection corrosion protection system ready for backfill

 

Each of our GPT anode packages are of the following size and specification, unless otherwise specially requested for another size & model to be installed

1) Anode Package Weight: 45 pounds.
2) Anode core weight: 17 pounds High Potential quality.
3) Wire: 20 feet long #8 gauge copper, jacketed HMWPE.
4) Anode core materials:

Magnesium/high quality. 98.839%.
Aluminum 0.01% max.
Manganese 1.0%  max.
Copper 0.02% max.
Silicon 0.05% max.
Iron 0.03% max.
Nickel 0.01% max.
Other each 0.05% max.

5) Anode package length/inches: 29"
6) Anode package diameter/inches: 6.5"
7) Package backfill material: 75% Gypsum, 20% Bentonite, 5% sodium Sulfate mix.

 

Voltage Measuring Procedure

The following are the 4 steps for the annual testing the "DC voltage" on a GPT-1, -2 or -3 Cathodic Anchor Shaft Protection cathodic protection systems with a digital volt meter. In addition to the meter the is a need for a small adjustable wrench to loosen & tighten the "set-bolt" on the beam-clamps at each anchor fan-plate.

1) While standing next to the anchor fan plate, loosen the "set-bolt" on the stainless steel beam clamp which has the anode wires connected to it & lift the beam clamp "away" from the anchor head fanplate.

2) With the beam clamp lifted away, use a low DC volt meter scale & touch one test lead on the anchor head fanplate & touch the other test lead on the stainless steel beam clamp & read the measured voltage.  Normal acceptable & good anode voltage readings are between -1. VDC &  -1.4 VDC.

3) Record the voltage value on your annual tower guy Cathodic Anchor Shaft Protection inspection report. If the voltage reads less than -.87 VDC there is a problem & the anodes may be depleted or anode wires may be cut & needs to be repaired or anodes replaced otherwise increase the number of anodes protecting an Cathodic Anchor Shaft Protection to attain a voltage reading higher than -1. volt DC.

4) Upon completion of the voltage measurement test, reinstall & tighten the stainless steel beam clamp "set-bolt" plus tighten any loose anode wire connections on the anchor head fanplate.

Note: In strong RF (radio frequency) fields near high power AM, FM, Microwave or TV broadcasting towers signals an "analog" meter may be a better choice of meters & less likely to be affected by RF signals when measuring the small DC voltages of anodes.