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Pavement Design Problem 1 - Flexible Pavement Design using UFC method:
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Design a flexible pavement section for a two lane road on rolling terrain that carries an average daily traffic volume of 2700 vehicles, containing on average 270 trucks
with 25 of them having 3 axles or more. Use a limerock base. The compacted subgrade has a CBR value of 10. |
1. In order to design this road it will be necessary to reference the UNIFIED FACILITIES DESIGN CRITERIA (UFC) - GENERAL PROVISIONS AND GEOMETRIC DESIGN FOR ROADS, STREETS, WALKS, AND OPEN STORAGE AREAS.
Chapter 1, Table 1 lists the road with the criteria specified as being a Class C road.
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2. Next reference the UNIFIED FACILITIES DESIGN CRITERIA (UFC) - PAVEMENT DESIGN FOR ROADS, STREETS, WALKS, AND OPEN STORAGE AREAS.
Section 3-2 lists a road having the truck traffic as described as being a Category III road. Next referencing table 3-1, a Class C road with Category 3 traffic has a Pavement Design Index of 4.
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3. From the pavement design submenu open the flexible pavement thickness calculation, DIFlex.aspx. Input the "Title" of the calculation, the "Designer/Checker" information and the calculated variables.
Click on the "Calculate" button and read the results. The required thickness of the flexible pavement section above the subgrade is 9.8 inches. Use 10 inches.
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4. Next again reference the UNIFIED FACILITIES DESIGN CRITERIA (UFC) - PAVEMENT DESIGN FOR ROADS, STREETS, WALKS, AND OPEN STORAGE AREAS.
Section 6-4 lists a limerock base as having a design CBR value of 80. Next referencing table 6-1, a road with a design CBR of 80 and a Design Index of 4, requires a minimum of 2 inches of asphalt over 4 inches of base, with a minimum section thickness of 6 inches.
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5. Summary
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The required road section thickness above the compacted subgrade is 10 inches and consists of 2 inches of asphalt over an 8 inch limerock base.
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