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Culvert Design Including Analysis Using FHWA HY8 Software and Selection of Materials

8 PDHs | March 22 and Tuesday, March 23

Instructor: Mark Peterson, P.E.

Purpose and Background

Culverts are used to carry water under urban and rural roadways. Proper design of a culvert includes a hydraulic analysis of the site conditions along with appropriate selection of pipe materials and end treatments. While some situations require a detailed hydraulic analysis using software such as HEC-RAS, many situations can be adequately analyzed with a simpler software package. This course will cover the use of the Federal Highway Administration's (FHWA) software package HY8, which is a straightforward and technically accurate approach to culvert analysis. It will also cover the situations in which a simple analysis such as HY8 is not appropriate.

Selection of the proper materials and end treatments, including headwalls, improved inlets, flared end sections and downstream riprap aprons are also important components of a good design and affect the performance and longevity of the installation. This course will cover all of these aspects of culvert design. Determining appropriate friction factors, pipe life, and minimum and maximum cover will also be addressed.

Course Benefits

Learn how to:

  • Model different culvert materials using HY8 software 
  • Model different inlet configurations using HY8 software 
  • Interpret output results from the HY8 software 
  • Select the appropriate software for culvert analysis, depending on the complexity of the site and the features of the software 
  • Select the appropriate concrete, corrugated metal, HDPE, or PPE for use as a culvert 
  • Determine the appropriate minimum and maximum cover for different culvert materials 
  • Protect the inlet and outlet of culverts from erosion

Learning Outcomes

  • Identify the basic data needed to analyze culverts, both urban and rural, using the FHWA HY8 model
  • Design a basic culvert with different material types 
  • Design a basic culvert with different inlet configurations 
  • Identify the results of the analysis in the software output 
  • Identify when use of HY8 software is appropriate, and when more complex software is needed  
  • Determine which pipe material is most appropriate for the hydraulics and other site conditions for a culvert installation
  • Understand how to select an appropriate friction factor for pressure and gravity pipes

Who should attend?

  • Civil engineers involved in designing culverts under roadways, or regulatory agency personnel responsible for review of culvert designs
  • Public Agency officials responsible for culvert designs

Course Outline

Time: 1:00 p.m. – 4:00 p.m. each day

  • Important parameters to consider in hydraulic analysis of a culvert
  • Selection of pipe materials and impacts on hydraulics, design life, and structural integrity
  • Data requirements for HY8
  • Basics of hydraulic analysis using HY8
  • Analysis of more complex situations
  • Other software options
  • Minimum and maximum cover
  • Installation considerations
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