Development of Guidelines for the Use of Intermediate Diaphragms on Precast Concrete Beam Superstructures

While there is clear guidance in both MDOT and AASHTO Bridge Design Standards for the use of intermediate diaphragms in bridge superstructures of all types that support a curved road (a radius of curvature of 800 feet or less) and for highly skewed (skew angle of 30 degrees or more) bridges, the guidance for the use of intermediate diaphragms on precast concrete bridges on a straight roadway and with a skew of less than 30 degrees is less clear if not silent. MDOT has surveyed other States in the past to determine their practice for the use of intermediate diaphragms but has found little consistency. With the increased use of precast concrete spread box beam and bulb tee beams, whose cross sections result in an increased resistance to lateral displacement or torsional rotation during the construction of a bridge superstructure, engineering judgement seems to suggest that the number of intermediate diaphragms may be able to be reduced if the need for the intermediate diaphragms isn’t eliminated entirely. Reducing the number of intermediate diaphragms could decrease the cost of the project, decrease the duration of construction, and result in more durable superstructures.


    • English


    • Status: Active
    • Contract Numbers:

      2019‐0314 Z1

    • Sponsor Organizations:

      Michigan Department of Transportation

      Murray Van Wagoner Building
      425 West Ottawa, P.O. Box 30050
      Lansing, MI  United States  48909
    • Performing Organizations:

      Western Michigan University

      1903 W. Michigan Avenue
      Kalamazoo, MI  United States  49008-5241
    • Start Date: 20191001
    • Expected Completion Date: 20210731
    • Actual Completion Date: 0

    Subject/Index Terms

    Filing Info

    • Accession Number: 01774511
    • Record Type: Research project
    • Source Agency: Michigan Department of Transportation
    • Contract Numbers: 2019‐0314 Z1
    • Files: RIP, STATEDOT
    • Created Date: Nov 25 2020 11:06AM