Examining Tower Guy Wire Anchor Rods Matthew J

Examining Tower Guy Wire Anchor Rods Matthew J. Parker Atmospheric Technologies Group William R. Hinz Non-Destructive Examinations Group Westinghouse Savannah River Company Aiken, South Carolina

Outline • • • Problem Corrosion Options for Examinations Sound. Anchor(TM) Long-term protection Standards

Potential Problem? Anchor rod failure can lead to tower collapse!

How can this happen? CORROSION: Galvanic or Electrolytic

Corrosion--Nature’s Way of Creating Balance

The Galvanic Series

Anchor Rod / Block

Anchor Rod Corrosion Scenarios Connections between unlike metals n Unlike soils--strata or backfill n Soil corrosivity--metals or concrete n Nearby underground electricity (electrolytic corrosion) n

Where can this happen? (unofficial survey-NUMUG, industry, consultant, Internet)

Excavations--Should I Dig? Common Industry Practice n Negative Factors – Labor intensive – Inherently damaging – Inadequate visual examination – Safety compromised during fill removal – Trenching regulations – Difficult to repeat

Sound. Anchor(TM) A Nondestructive Examination Technique Patent 6, 311, 565 received Nov 6, 2001 Advantages • After minor initial surface preparation, test is conducted quickly • Non-damaging • More thorough examination • Inherently safe • Easily repeatable • Trending possible • One-tenth of the cost of excavations

Protection--How do I save what I already have? n Options for Protection – Protective coatings Bituminous (carcinogenic) n Galvanized n Polymers n – Cathodic Protection – Encase new rods in concrete

Where can I find more information? TIA/EIA Standard “Structural Standards for Steel Antenna Towers and Antenna Supporting Structures” n Reputable tower erection companies n