Bridge Service Life Design

High costs and traffic disruption associated with the deterioration of reinforced concrete bridge decks because of corrosion have sparked renewed interest in service life design. Reinforced concrete bridge decks are exposed to chlorides from deicing salts; when the chlorides reach the steel reinforcement, they initiate corrosion. This study supports the adoption of the methodology described in fib Bulletin 34, Model Code for Service Life Design, for reinforced concrete bridge decks in Virginia. Concrete mixture properties and environmental exposure conditions were characterized. Values particular to regions within Virginia and suggested default values were identified and organized in a database to support the development of service life design guidelines. The predicted service life for eight bridge decks using low-cracking concrete and corrosion-resistant reinforcement (VDOT Reinforcement Class I, MMFX, ASTM 1035) was evaluated. The service life model was also implemented in a life-cycle cost analysis for a case study bridge, which found superior reliability of corrosion-resistant reinforcement from a life-cycle perspective. In addition to supporting the implementation of service life design, several investigations identified key assumptions and variables in the service life model and identified critical areas for future characterization. The partial differential equation for apparent chloride diffusion was solved with both an approximate analytical approach and a numerical approach. Delays in the application of deicing salt were investigated using the numerical approach, and a ramp-type function for surface chloride concentration was explored using the analytical approach. Aging coefficients based on curing were also considered. A sensitivity analysis identified the aging coefficient and the surface chloride concentration as the most critical variables. The study concluded that sufficient data are available to implement the fib Model Code for Service Life Design, but that caution in interpreting results is warranted because of the high uncertainty associated with the most critical variables. According to the results of the service life analyses, the regional climatic variability and differences in mix design across Virginia indicate that a “one-size-fits-all” approach to bridge deck specifications may not be appropriate. The use of corrosion-resistant steel and low-cracking concrete mixtures can provide a substantial (greater than 100 years) bridge deck service life.

• Record URL:
  http://www.virginiadot.org/vtrc/main/online_reports/pdf/18-R1.pdf
• 
• Summary URL:
  http://vtrc.virginiadot.org/PubDetails.aspx?PubNo=18-R1
• Corporate Authors:

  Virginia Polytechnic Institute and State University, Blacksburg

  Charles Edward Via, Jr. Department of Civil and Environmental Engineering
  Blacksburg, VA  United States  24061

  Virginia Department of Transportation

  1401 E Broad Street
  Richmond, VA  United States  23219

  Federal Highway Administration

  400 North 8th Street
  Richmond, VA  United States  23219-4825
• Authors:
  • Bales, Elizabeth Rose
  • Chitrapu, Venkatasaikrishna
  • Flint, Madeleine M
• Publication Date: 2018-6

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Contract
• Features: Figures; References; Tables;
• Pagination: 34p

Subject/Index Terms

• TRT Terms: Admixtures; Bridge decks; Bridge design; Design standards; Life cycle costing; Reinforced concrete bridges; Service life
• Geographic Terms: Virginia
• Subject Areas: Bridges and other structures; Design; Highways; Maintenance and Preservation;

Filing Info

• Accession Number: 01675715
• Record Type: Publication
• Report/Paper Numbers: FHWA/VTRC 18-R1
• Contract Numbers: 107645
• Files: TRIS, ATRI, USDOT, STATEDOT
• Created Date: Jul 23 2018 2:12PM