UNIVERSITY OF PITTSBURGH | SWANSON SCHOOL OF ENGINEERING | CIVIL & ENVIRONMENTAL Steel Bridge Corrosion Prevention and Mitigation Strategies A Literature Review August, 2019 IRISE Consortium Impactful Resilient Infrastructure Science and Engineering Technical Report Document Page 1. Report No: IRISE-19-P19-01-01 2. Report Date: August, 2019 3. Report Title: Steel Bridge Corrosion Prevention 4. Authors: Max T. Stephens, Brian Gleeson, and Mitigation Strategies : Literature Review Jason Mash and Bingtao Li 5. Performing Organization Name and Address 6. Sponsoring Organization Name and Address: Department of Civil & Environmental Engineering IRISE 742 Benedum Hall Department of Civil & Environmental Engineering University of Pittsburgh 742 Benedum Hall Pittsburgh, PA 15261 University of Pittsburgh Pittsburgh, PA 15261 7. Abstract: Corrosion in steel bridges exposed to chloride attack from exposure to marine environments or de-icing salts is a significant issue which decreases structural integrity and increases maintenance requirements. Steel bridges exposed to these conditions require regular inspection, maintenance and rehabilitation, which drastically increases life-cycle costs. This report provides a comprehensive literature review which highlights important issues related to corrosion in steel bridges with the objective of identifying shortcomings in current practice in Pennsylvania and identifying novel methods for further study and/or possible implementation. First, common forms of corrosion in steel infrastructure are reviewed. Next, corrosion prevention, mitigation and repair strategies are discussed including strategies currently utilized in Pennsylvania and by other state DOTs. Finally, promising corrosion prevention, mitigation and repair solutions are recommended. These solutions include: (1) implementing duplex coating systems, (2) identifying and evaluating novel approaches to prevent and mitigate crevice corrosion, (3) developing AI enabled corrosion monitoring methodologies, (4) eliminating joints in existing structures using debonded link slabs, and (5) further developing in-situ repair strategies for corrosion damaged components. 8. Key Words: 9. Distribution: Report available at: https://www.engineering.pitt.edu/IRISE/Research- Projects/Completed/ i Steel Bridge Corrosion Prevention and Mitigation Strategies: Literature Review August 2019 Authors Max T. Stephens, Ph.D., University of Pittsburgh Brian Gleeson, Ph.D., University of Pittsburgh Jason Mash, P.E., University of Pittsburgh at Johnstown Bingtao Li, Ph.D., University of Pittsburgh Technical Reviewers Jonathan Buck, P.E., Federal Highway Administration Lou Ruzzi, P.E., Pennsylvania Department of Transportation Stephen Shanley, P.E., Allegheny County ii IRISE The Impactful Resilient Infrastructure Science & Engineering consortium was established in the Department of Civil and Environmental Acknowledgements Engineering in the Swanson School of The authors gratefully acknowledge the Engineering at the University of Pittsburgh to financial support of all contributing members of address the challenges associated with aging IRISE. In addition, we are indebted to the advice transportation infrastructure. IRISE is and assistance provided by Mr. Louis Ruzzi of addressing these challenges with a the Pennsylvania Department of Transportation comprehensive approach that includes and Mr. Stephen Shanley of Allegheny County. knowledge gathering, decision making, material durability and structural repair. It features a Disclaimer collaborative effort among the public agencies The views and conclusions contained in this that own and operate the infrastructure, the document are those of the authors and should private companies that design and build it and not be interpreted as representing official the academic community to develop creative policies, either expressed or implied, of the solutions that can be implemented to meet the Pennsylvania Department of Transportation, needs of its members. To learn more, visit: the Pennsylvania Turnpike Commission, https://www.engineering.pitt.edu/irise/. Allegheny County, Golden Triangle Construction, or Michael Baker International. iii Table of Contents 1 Introduction ............................................................................................................................. 1 2 Forms of Corrosion Common to Steel Bridges ....................................................................... 3 2.1 Forms of Corrosion .......................................................................................................... 3 2.1.1 Uniform Corrosion .................................................................................................... 4 2.1.2 Galvanic Corrosion ................................................................................................... 4 2.1.3 Crevice Corrosion ..................................................................................................... 5 2.1.4 Pitting Corrosion ....................................................................................................... 6 2.1.5 Intergranular Corrosion ............................................................................................. 7 2.1.6 Selective Leaching / De-alloying .............................................................................. 7 2.1.7 Erosion Corrosion ..................................................................................................... 7 2.1.8 Stress Corrosion ........................................................................................................ 8 2.2 Common Forms of Corrosion in Girder-Type Bridges .................................................... 9 3 Corrosion Protection Approaches for Steel Bridges.............................................................. 11 3.1 Paint Coatings ................................................................................................................ 13 3.2 Galvanized Coatings ...................................................................................................... 17 3.3 Thermal Spray Metallic Coatings .................................................................................. 19 3.4 Weathering Steels ........................................................................................................... 21 3.5 Stainless Steels ............................................................................................................... 22 3.6 Duplex Coatings ............................................................................................................. 23 3.7 Summary of Steel Bridge Corrosion Protection Strategies ............................................ 24 3.8 Crevice Corrosion Protection ......................................................................................... 24 4 State of Corrosion Prevention/Mitigation Strategies Used in Pennsylvania ......................... 26 4.1 Coating Systems ............................................................................................................. 26 4.1.1 Shop Painting of New Structures ............................................................................ 26 4.1.2 Field Painting of Existing Structures ...................................................................... 27 4.2 Crevice Corrosion Prevention/Mitigation ...................................................................... 30 4.3 Corrosion-Resistant Steels ............................................................................................. 30 4.4 Avoidance or Elimination of Corrosion Prone Details .................................................. 31 4.4.1 Deck Drainage Systems .......................................................................................... 31 4.4.2 Joints ....................................................................................................................... 32 4.5 Structural Repairs ........................................................................................................... 33 iv 5 US DOT Corrosion Prevention and Mitigation Strategies .................................................... 34 5.1 Coating Systems ............................................................................................................. 34 5.1.1 State DOT Coating Requirements .......................................................................... 34 5.1.2 Trends in Coating Systems ..................................................................................... 34 5.1.3 Single Overcoat Maintenance ................................................................................. 36 5.2 Weathering Steel ............................................................................................................ 37 5.3 Stainless Steels ............................................................................................................... 38 5.4 Crevice Corrosion .......................................................................................................... 39 5.5 Removal of Corrosion Prone Details ............................................................................. 40 6 Novel Structural Rehabilitation Methods Evaluated in Research ......................................... 41 6.1 Carbon Fiber Reinforced Polymers (CFRP) .................................................................. 41 6.2 Ultra-High Performance Concrete (UHPC) ................................................................... 42 7 Summary and Recommendations for