Development of Adjustment Factors and Bridge Load Ratings through Statistical Analyses of the NBI Database

The Kansas Department of Transportation (KDOT) is in the process of load rating all bridges in the state inventory. This effort, mandated by the Federal Highway Administration (FHWA), includes the nearly 20,000 structures comprising the Kansas Local System. Many of these structures have no design or as-built plans, including approximately 8,000 concrete bridges. Load ratings can be cost-effectively assigned to bridges without plans based on traffic loads and bridge condition (Lequesne and Collins, 2019). However, this requires the bridge to be in fair or better condition and limits the bridge capacity to current/historical traffic loads. This approach is inadequate for bridges undergoing a change in use, requiring evaluation for over-weight vehicles, or requiring special evaluation due to damage or deterioration. The research team proposes to examine the National Bridge Inventory (NBI) database using statistical methods to provide a cost-effective means of assigning load ratings to most structures in Kansas. The process would identify key variables (e.g. span, age, and condition) that correlate with inventory and operating ratings and produce “expected” load rating values for most bridges in Kansas. The analyses will provide a statistically sound means of establishing: (1) “adjustment factors” used to adjust load ratings to account for bridge condition, (2) baseline load rating estimates for structures without prior ratings, and 3) secondary load ratings used to “check” load ratings determined using other methods to identify outliers and potential errors.

  • Supplemental Notes:
    • Final report is pending review.


  • English


  • Status: Active
  • Funding: $46500
  • Contract Numbers:

    K-TRAN: KU-22-2



  • Sponsor Organizations:

    Kansas Department of Transportation

    Eisenhower State Office Building
    700 SW Harrison Street
    Topeka, KS  United States  66603-3754
  • Performing Organizations:

    University of Kansas Center for Research, Incorporated

    2291 Irving Hill Drive, Campus West
    Lawrence, KS  United States  66045
  • Principal Investigators:

    Husic, Admin

    Collins, William

    Roundy, Joshua

  • Start Date: 20210801
  • Expected Completion Date: 20240731
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01832312
  • Record Type: Research project
  • Source Agency: Kansas Department of Transportation
  • Contract Numbers: K-TRAN: KU-22-2, RE-0830-01, C2190
  • Files: RIP, STATEDOT
  • Created Date: Jan 7 2022 1:01PM