flexible pavement design aashto method example

Layer coefficients used were 0.44 for HMA and 0.13 for crushed stoneįrost design requirements must be checked if subgrade soil frost susceptible Pavements are typically designed for the critical lane or “design lane”, which accounts for traffic distribution.ĮSALs per year = (Vehicles/day) (Lane Distribution Factor) (days/yr) (ESALs/Vehicle)

This step involves converting the daily traffic volume into an annual ESAL amount. Work can be verified by using the Flexible Pavement Structural Design Utility. Truck trains – trucks with more than 2 units (assume 1.75 ESALs per truck) = 247/dayīy looking at several different design periods and reliability levels this example gives an idea of the relative influence of these inputs. Single unit trucks (assume 0.40 ESALs per truck) = 1872/dayĭouble unit trucks (assume 1.00 ESALs per truck) = 1762/day This represents a typical range of reliability levels encountered for Interstate highways.

Investigate three levels: R = 90%, R = 95%, R = 99%. M R = 86 MPa (12,500 psi) in the wet months of November through April M R = 103 MPa (15,000 psi) in the dry months of May through October Use E = 3,447 MPa (500,000 psi) Base course: Crushed aggregate with M R= 193 MPa (28,000 psi)Subbase course: None used Surface course: 12.5 mm (0.5 inch) Superpave with E = 3,447 MPa (500,000 psi)Binder course: Dense-graded HMA mix with a nominal maximum aggregate sizeof 25 mm (1 inch). Investigate 20, 30 and 40 year design periods

Assume 80% of the loading occurs in the design lane

Flexible pavement design aashto method example