Analysis of Curb Inlets in the New TxDOT Standard Inlet and Manhole Program

This project will provide design guidance for the flow performance of the new TxDOT standard on-grade Type PCO precast curb inlet. The new curb inlet uses flush slab supports for inlets longer than 5 ft., which is required in Texas due to small road slopes and intense rainfall rates. The flush slab supports are thought to cause a substantial decrease in the curb inlet capacity, but there are no examples of inlet experiments in the literature that can be used to quantify the effect of the slab supports. Without new guidance on inlet capacity with slab supports, roadway designers must resort to making rough estimates of probable drainage effects, which could result in significant over- or under-capacity designs. The research team shall conduct full-scale experiments using the existing UT Roadway Physical Model and to analyze the experimental results to provide a set of flow equations for inlet behavior that can be used in standard design software (for example, GeoPak Drainage). The research team shall test the new inlet design both with and without slab supports with the standard opening sizes (5, 9.5, 14 ft.) over a variety of roadway longitudinal and cross slopes at different flow rates and roadway roughness. This research team shall determine how the new precast curb inlet will behave, which is critical to making best use of the new standards.


  • English


  • Status: Completed
  • Funding: $415,655
  • Contract Numbers:


  • Sponsor Organizations:

    Texas Department of Transportation

    125 E. 11th Street
    Austin, TX  United States  78701-2483
  • Project Managers:

    Odell, Wade

  • Performing Organizations:

    University of Texas, Austin

    Center for Transportation Research
    3925 W. Braker Lane, 4th Floor
    Austin, TX  United States  78759
  • Principal Investigators:

    Hodges, Ben

  • Start Date: 20150115
  • Expected Completion Date: 20180531
  • Actual Completion Date: 0
  • Source Data: RiP Project 39145

Subject/Index Terms

Filing Info

  • Accession Number: 01569109
  • Record Type: Research project
  • Source Agency: Texas Department of Transportation
  • Contract Numbers: 0-6842
  • Files: RiP, STATEDOT
  • Created Date: Jul 1 2015 2:46AM