Control of Cracking in Concrete Bridge Decks

According to AASHTO LRFD Bridge Design Specifications (LRFD BDS), there are two main methods of bridge deck design. The more analytical “Strip Method” tends to place a limit on rebar spacing. The limit is based on crack width limitations developed for building beams and adapted in the American Association of State Highway and Transportation Officials (AASHTO) for flexural reinforcement in deck slabs several decades ago. The implied maximum crack width, according to the provisions of AASHTO, Article 5.6.7, for moderate exposure to corrosion is 0.017 in. Such limitation has been shown in practice to be prohibitive when high-strength rebars, whether corrosion resistant or not, are used. In the meantime, there does not appear to be adequate evidence that longitudinal cracks across the main transverse reinforcement are as dominant as transverse cracks across the secondary longitudinal bars. The second method is the “Empirical Design Method” in Chapter 9 of AASHTO LRFD BDS. This method gives prescriptive reinforcement based on full-scale testing performed in Ontario, Canada, in the 1970s. Interestingly, the Empirical Design Method results in lower rebar quantities than the more rigorous Strip Method. Further, the Empirical Design Method has no requirement for flexural crack control equations. Thus, it appears that the mechanics of load transfer in deck slabs need to be fundamentally examined. The objectives of this research, limited to reinforced concrete bridge decks supported on structural steel or concrete girders, are: (1) To develop a comprehensive understanding of the causes of cracking in cast-in-place concrete bridge decks that are placed on girders. This may include full-depth precast concrete bridge decks. (2) To develop methods of controlling cracks by the identified causes. Such methods shall include concrete material properties, rebar types and properties, chemical admixtures, and curing methods. (3) To review and modify the current AASHTO provisions relative to crack control. This would include the provisions of Article 5.6.7—Control of Cracking by Distribution of Reinforcement. Such revisions should be based on a rational interpretation of the available body of knowledge in addition to actual field demonstrations. (4) To examine the serviceability requirements for the Strip Method (Article 5.6.7) and the Empirical Design Method (Article 9.7.2).

• Record URL:
  • http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=6046
• Supplemental Notes:
  • Contract to a Performing Organization has not yet been awarded.

Language

• English

Project

• Status: Proposed
• Funding: $750,000.00
• Contract Numbers:

  Project 12-134

• Sponsor Organizations:

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001

  American Association of State Highway and Transportation Officials (AASHTO)

  444 North Capitol Street, NW
  Washington, DC  United States  20001

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Project Managers:

  Abu-Hawash, Ahmad

• Start Date: 20260608
• Expected Completion Date: 0
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Bridge decks; Bridge design; Cast in place structures; Concrete bridges; Cracking
• Identifier Terms: AASHTO LRFD Bridge Design Specifications
• Subject Areas: Bridges and other structures; Design; Highways;

Filing Info

• Accession Number: 01992190
• Record Type: Research project
• Source Agency: Transportation Research Board
• Contract Numbers: Project 12-134
• Files: TRB, RIP
• Created Date: Jun 9 2026 4:01PM