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 Roadway Design: Lab Exercises

 
Lab Exercise One: Roadway Design

In this lab exercise, you will be required to define the best alignment for a highway connecting two or more separate points on a topographical map. The topographical map may be supplied by your instructor, or you may be asked to find an appropriate map on your own. Your instructor will select the points that must be connected by your roadway.

Your design should:

  • avoid damaging areas that are environmentally sensitive.
  • include plots of the vertical profile of your roadway and existing points on the ground.
  • obey AASHTO or local geometric design guidelines for setting grades, vertical curves, sight distances, and drainage requirements.
  • include end area profiles (cut and fill) and complete earthwork calculations, using an appropriate shrinkage factor.

Your final design should be accompanied by a brief report that summarizes the details and features of your selected design.

If you are unable to find a suitable topographic map, the AutoCAD drawings below may be used with your instructor's permission. If you do not have access to AutoCAD, you can download the WHIP viewer, which will allow you to view and print the drawings.

Tasks to be Completed

 Task 1. Acquire a topographic map of a suitable area. Discuss possible ‘terminal’ points with your instructor and define any areas that are environmentally sensitive or especially hazardous.

Task 2. Develop an optimum roadway alignment. Review AASHTO and/or local guidelines to check for grades, vertical curves, sight distances, or drainage requirements that are not met by the selected alignment. Modify as necessary.

Task 3. Prepare a vertical profile diagram of the ground and centerline for the selected route by following the rules listed below.

  • State distances in feet from the end of the project.
  • Round horizontal distances to nearest 50 ft.
  • Calculate elevations along the alignment at every 100-ft station.

Task 4. At 100-ft stations, prepare cross-section diagrams of the ground and superimpose a highway cross-section template. Calculate cut and fill areas. Section lengths and average end areas may be used to calculate the cut and fill volumes.

Task 5. Complete the earthwork calculations using an appropriate shrinkage factor. Prepare a mass-haul diagram and determine whether you will have to borrow or waste any material in order to complete the project. Attempt to balance cut and fills.