Protocol to Evaluate and Load Rate Existing Bridges

Numerous bridges in Nebraska require evaluation to verify their ability to safely carry traffic. Recent Federal Highway Administration (FHWA) Long-Term Bridge Performance Program (LTBP) guidelines provide a solid basis for the rational evaluation of existing bridges. In rural areas, there are many county bridges that require non-conventional methods of evaluation to verify their capacity or to upgrade their postings; in-lieu of replacement or traffic rerouting. Evaluation and rating procedures are listed in the American Association of State Highway and Transportation Officials (AASHTO) Manual for Bridge Evaluation (in particular, Chapters 6 and 8 for rating and testing, respectively). Strict requirements apply to state owned structures. However, these federal requirements are not necessarily applicable to off-system bridges, including those that are owned by counties or other local transportation agencies. Regardless, all bridge owners are responsible for the safety of the traveling public using public infrastructure. Therefore, bridge owners are interested in knowing the actual load carrying capacity of the structures within their jurisdiction, as well as knowing the expected loads caused by traffic. Available field testing procedures can vary in terms of accuracy, ease of installation and operation of testing equipment, investment cost and cost of operation, power supply requirements, qualifications of the operators, data processing capability, and so on. Therefore, there is a need to develop a practical guide for field testing procedures within an accepted protocol for bridge owners in Nebraska. The objective of this proposed project is to develop a protocol for the evaluation of existing bridges in Nebraska. The protocol will be specifically prepared for any bridges, which are in question about their performance and capacity; however older rural bridges may be most applicable. The guide to bridge evaluation and rating will be consistent with the AASHTO Manual for Bridge Evaluation and Nebraska Department of Roads (NDOR) Bridge Inspection Program requirements. The proposed research will involve the selection of representative bridges of various construction style and material, both for state-owned and off-system bridges, as well as the identification of problems to be addressed--for example, verification of the load distribution factors, actual live load (weight of trucks), dynamic load factors, or minimum load carrying capacity. The available field testing procedures will be presented and described, focusing on Nebraska-specific applications. The developed protocol will include descriptions of the equipment and operational guides, and present the method of rating bridge based on field test results. The protocols will include the assessment of accuracy, potential problems, and best practice observations.


    • English


    • Status: Active
    • Funding: $67733.00
    • Contract Numbers:

      SPR-P1(16) M044

    • Sponsor Organizations:

      Federal Highway Administration

      1200 New Jersey Avenue, SE
      Washington, DC  United States  20590

      Nebraska Department of Roads

      1500 Highway 2
      Lincoln, NE  United States  68502
    • Performing Organizations:

      University of Nebraska, Lincoln

      527 Nebraska Hall
      Lincoln, NE  United States  68588-0529
    • Principal Investigators:

      Szerszen, Maria

    • Start Date: 20150701
    • Expected Completion Date: 0
    • Actual Completion Date: 20161231
    • Source Data: RiP Project 39676

    Subject/Index Terms

    Filing Info

    • Accession Number: 01569410
    • Record Type: Research project
    • Source Agency: Nebraska Department of Roads
    • Contract Numbers: SPR-P1(16) M044
    • Files: RiP, STATEDOT
    • Created Date: Jul 11 2015 1:00AM