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Inspection and Maintenance of Weathering Steel Bridges Douglas D. Crampton, P.E., S.E.

Inspection and Maintenance of Weathering Steel Bridges Douglas D. Crampton, P.E., S.E. Wiss, Janney, Elstner Associates. History of Weathering Steel Bridges in Iowa. 1930’s: Weathering steel first evolved 1964: First used for a bridge application 1980: Michigan moratorium, Iowa followed

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Inspection and Maintenance of Weathering Steel Bridges Douglas D. Crampton, P.E., S.E.

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  1. Inspection and Maintenance of Weathering Steel Bridges Douglas D. Crampton, P.E., S.E. Wiss, Janney, Elstner Associates

  2. History of Weathering Steel Bridges in Iowa • 1930’s: Weathering steel first evolved • 1964: First used for a bridge application • 1980: Michigan moratorium, Iowa followed • Research studies • Mid-1990’s: Weathering steel bridges reintroduced in Iowa • Recent years: Certain Iowa bridges are not performing properly • Currently Iowa has approximately 139 weathering steel bridges • 97% were constructed after 1994 Solutions for the Built World

  3. Typical Patina Behavior Excessive chlorides, poor exposure, increased time of wetness Protective Rust Solutions for the Built World

  4. Project Objectives • Identify problematic bridges • Identify problematic locations or details • Evaluate inspection techniques • Prioritize bridges: • Condition • Location • Exposure • Recommend maintenance program Solutions for the Built World

  5. Field Investigation Solutions for the Built World

  6. Inspection and Testing Methods • Visual Inspection • Chloride Testing • Tape Adhesion • Color Testing • Core Samples • SEM/FTIR/XRD Solutions for the Built World

  7. Inspection and Testing Methods • Goals of Inspection Method: • Consistent • Reliable • Repeatable • Objective Results • Visual Inspection: easy and practical, but not always objective • Tape Adhesion Tests: simple, practical, and objective • Color Testing: not always consistent • Chloride Testing: not always reliable • Core Samples, SEM, XRD: not practical or cost effective Solutions for the Built World

  8. Inspection and Testing Methods Non-Protective Thick Rust Increasing Flake Size Protective Rust Solutions for the Built World

  9. Proposed Rating Scale (NBIS Format) • Overall Appearance • Flake Size and Density • Color and Consistency

  10. Example 1: No Chloride Exposure Solutions for the Built World

  11. Example 1: No Chloride Exposure

  12. Example 1: No Chloride Exposure

  13. Example 2: Chloride Exposure Solutions for the Built World

  14. Example 2: Chloride Exposure Solutions for the Built World

  15. Example 2: Chloride Exposure Solutions for the Built World

  16. Example 2b: Chloride Exposure Solutions for the Built World

  17. Example 2b: Chloride Exposure Solutions for the Built World

  18. Example 2b: Chloride Exposure Solutions for the Built World

  19. Example 2b: Chloride Exposure Solutions for the Built World

  20. Iowa Weathering Steel BridgesConditions Affecting Patina Performance • Chloride Use: • Salted from above • Salt spray from below • Both • Time of wetness • Location: • Urban • Suburban • Rural • Exposure: • Bold • Sheltered • Tunnel Effect • Service Below: • Interstate or waterway • Low clearance? • High % trucks? • Detailing Solutions for the Built World

  21. Iowa Weathering Steel Bridges Solutions for the Built World

  22. Iowa Weathering Steel Bridges Solutions for the Built World

  23. Iowa Weathering Steel Bridges Solutions for the Built World

  24. Iowa Weathering Steel Bridges Solutions for the Built World

  25. Iowa Weathering Steel Bridges Solutions for the Built World

  26. Prioritization and Maintenance Solutions for the Built World

  27. Prioritization and Maintenance Solutions for the Built World

  28. Prioritization and Maintenance Proposed Washing Intervals Solutions for the Built World

  29. Prioritization and Maintenance Proposed Patina Maintenance Solutions for the Built World

  30. Questions? Douglas D. Crampton, P.E., S.E. Wiss, Janney, Elstner Associates Northbrook, Illinois (847) 272-7400 dcrampton@wje.com www.wje.com

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