Examining Tower Guy Examining Tower Guy Wire Anchor RodsWire Anchor Rods

Matthew J. ParkerMatthew J. Parker

Atmospheric Technologies GroupAtmospheric Technologies Group

William R. HinzWilliam R. Hinz

Non-Destructive Examinations GroupNon-Destructive Examinations Group

Westinghouse Savannah River Westinghouse Savannah River CompanyCompany

Aiken, South CarolinaAiken, South Carolina

OutlineOutline

• Problem• Problem• Corrosion• Corrosion• Options for • Options for ExaminationsExaminations• SoundAnchor(TM)• SoundAnchor(TM)• Long-term protection• Long-term protection• Standards• Standards

Potential Problem?Potential Problem?

Anchor rod failure can Anchor rod failure can lead to tower collapse!lead to tower collapse!

How can this How can this happen?happen?

CORROSION:CORROSION:Galvanic orGalvanic orElectrolyticElectrolytic

Corrosion--Nature’s Way of Corrosion--Nature’s Way of Creating BalanceCreating Balance

Natural State to Man-Made State to Natural State

STEEL

OXIDEOXIDE

Refining

Milling

Corrosion

ENERGY ADDED ENERGY RELEASED

The Galvanic SeriesThe Galvanic SeriesHierarchy of the Galvanic Series

Gold

Platinum

Carbon

Silver

Nickel

Copper

Iron

Aluminum

Zinc

Magnesium

Anchor Rod / BlockAnchor Rod / Block

Grade

AnchorRod

Several feet

Copper ground rod

Copper ground cable

Anchor Rod Corrosion Anchor Rod Corrosion ScenariosScenarios

Connections between unlike Connections between unlike metalsmetals

Unlike soils--strata or backfillUnlike soils--strata or backfill Soil corrosivity--metals or concreteSoil corrosivity--metals or concrete Nearby underground electricity Nearby underground electricity

(electrolytic corrosion)(electrolytic corrosion)

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

Excavations--Should I Dig?Excavations--Should I Dig?Common Industry PracticeCommon Industry Practice

Negative FactorsNegative Factors– Labor intensiveLabor intensive– Inherently damagingInherently damaging– Inadequate visual examinationInadequate visual examination– Safety compromised during fill Safety compromised during fill

removalremoval– Trenching regulationsTrenching regulations– Difficult to repeatDifficult to repeat

SoundAnchor(TM)SoundAnchor(TM)A Nondestructive Examination A Nondestructive Examination

TechniqueTechnique Patent 6,311,565 received Nov 6, 2001Patent 6,311,565 received Nov 6, 2001

AdvantagesAdvantages• • After minor initial surface preparation, After minor initial surface preparation,

test is conducted quicklytest is conducted quickly

• • Non-damagingNon-damaging

• • More thorough examinationMore thorough examination

• • Inherently safeInherently safe

• • Easily repeatableEasily repeatable

• • Trending possibleTrending possible

• • One-tenth of the cost of excavationsOne-tenth of the cost of excavations

Entry surface

Back-wall reflection

Unflawed Anchor

SoundAnchor(TM) Signal Interpretation

Flawed Anchor

Typical of planarflaw (crack)

Flawed Anchor

Typical of wastage

Protection--How do I saveProtection--How do I savewhat I already have?what I already have?

Options for ProtectionOptions for Protection– Protective coatingsProtective coatings

Bituminous (carcinogenic)Bituminous (carcinogenic) GalvanizedGalvanized PolymersPolymers

– Cathodic ProtectionCathodic Protection– Encase new rods in concreteEncase new rods in concrete

Where can I find moreWhere can I find moreinformation?information?

TIA/EIA Standard “Structural TIA/EIA Standard “Structural Standards for Steel Antenna Towers Standards for Steel Antenna Towers and Antenna Supporting Structures”and Antenna Supporting Structures”

Reputable tower erection companiesReputable tower erection companies