Presentation on theme: "Valmont Servies Group NCSC Omaha Conference October 8, 2013 BABY BOOMER POLES AILMENTS AND FIXES CARL KEMPKES, NACE III CIP DIRECTOR OF OPERATIONS MATCO."— Presentation transcript:
Valmont Servies Group NCSC Omaha Conference October 8, 2013 BABY BOOMER POLES AILMENTS AND FIXES CARL KEMPKES, NACE III CIP DIRECTOR OF OPERATIONS MATCO SERVICES VALMONT INDUSTRIES
Baby Boomer Poles... Been around for a while Still have some life in them... but they now have some aches and pains
Objectives of this presentation Understanding issues that affect pole service life Basics in evaluating pole condition Considerations to increase pole service life
Baby Boomer Poles... What the industry sees: Paint & Coating Failures Corrosion Failures Fatigue Failures
Is what we see...
Steel/Aluminum Poles: Life is determined by how well we can control... Corrosion Fatigue Overload
Corrosion is the primary destroyer of poles Corrosion... The deterioration of the metal due to reaction with the environment.
Corrosion Cycle Iron Ore Fe 2 O 3 Blast Furnace – Reduction to Fe Steelmaking Furnace Structural Steel Oxidation of Fe – Rust - Fe 2 O 3
Coatings Provide the Primary Defense for Corrosion Protection However, all coatings have a limited life determined by: Barrier Protection Adhesion UV Protection Resistance to Mechanical Damage Corrosion Mechanisms Environmental Considerations Installation
Factors to be considered before a coating system is specified. Type of substrate Service Environment and Conditions Durability to Mechanical Damage Barrier Properties Long Term Appearance
As Coating Systems Are Not Created Equal, Comparative Tier Testing Is Recommended Adhesion Properties (resin and preparation) Cathodic Delamination (resin that has alkaline/salt resistance) Barrier Properties (resists pin holes & gassing, allows for thickness, covers sharp edges) E.I.S. Impact Resistance, Toughness to Mechanical Damage & Road Debris (strength and ductility) Galvanic Protection (zinc) Color and Gloss Retention (UV resistance)
Example of Cathodic Delamination Testing
What Is Electrochemical Impedance Spectroscopy (EIS)? Non-destructive testing technique for evaluating the protection of organic coatings. Uses AC current to measure the electrical resistance (impedance) of a coating. Used to assess coating integrity following deterioration.
Installation is Important Gap allows drainage and prevents water/moisture build-up. “Immersion” style conditions do not allow moisture to run- off.
Installation: Grouting Can Be Problematic
Can Lead to Internal Corrosion
Grouting can promote corrosion
Let’s also look inside: Grouting can contribute to internal corrosion due impeded drainage
Improperly set poles may cause water/moisture retention. Pole “buried” when set. “Buried” poles can not drain. As a result, internal and external corrosion may occur. Ground Line Corrosion attack below grade. Corrosion Failure of “Buried” Pole
Valmont Services Group - 08/23/2010 (Page 25) Built-up Landscaping:
Pole corrosion can lead to... …. this type of damage
What can we do... structural repair with collar
Wind Induced Vibration Fatigue Fatigue... Although rare, pole vibrations severe enough to accelerate pole fatigue can occur and damage a pole.
What “Fatigue” is... Fatigue is the progressive failure of a component subjected to repeated strains at stresses below the yield strength of the material.
Fatigue Failures Can Be Catastrophic!
Pole Metal Fatigue
Cyclic Wind Loads
Example of Fatigue Crack
Valmont Services Group - 08/23/2010 (Page 34) Loose Anchor Bolt Nuts May Promote Fatigue
Fatigue Crack Above Weld
When visual may not be good enough: Nondestructive Testing Ultrasonic Magnetic particle Liquid penetrant Radiography
NDT reveals cracks and discontinuities not readily apparent with the naked eye
Importance of Annual Maintenance: There are no maintenance free poles. Inspection determines the current state condition of a pole. Inspection catches and mitigates corrosion and/or fatigue issues early to ensure cost effective repair procedures. Maintenance extends pole life and reduces pole lifetime costs.
Summary Poles are at risk in corrosive environments Failures due to corrosion will occur just a matter of time if not detected Fatigue and corrosion deterioration accelerates over time Fatigue, while rare is influenced by many interacting variables including loose anchorage, major wind events and/or cyclic wind conditions.
Summary Inspection determines the current state of a pole. It lets the owner make decisions in an informed data driven way. Inspection identifies poles that need immediate attention which reduces liability concerns and promotes risk management of assets. Inspection allows for maintenance and replacement planning and allocation.