Selection of the highest values for design reliability, R, results in significant increases in Sn. AASHTOWare Pavement ME Design is the next generation of AASHTOWare pavement design software, which builds upon the mechanistic-empirical pavement design. Variation in the predicted number of 18-kip equivalent single-axle loads, W 18, has a lesser effect, and variation in combined standard error, S o, has a minimal effect on S n. Study results show that variation in subgrade resilient modulus, M R, has the most pronounced effect on thickness structural number, SN.
Flexible pavement design aashto download#
A physical or digital download copy of the guide may be. The study demonstrates the relative importance of design equation input parameters and provides insights into the relative change in required pavement structure thickness resulting from variations or errors in input parameter values. This tool follows AASHTO Guide for Design of Pavement Structures (1993) as closely as possible. The predicted loading is simply the predicted number of 80 kN (18,000 lb.) ESALs that the pavement will experience over its design lifetime. This paper summarizes the results of a significance study performed using the revised flexible pavement design equation. The 1993 AASHTO Guide equation requires a number of inputs related to loads, pavement structure and subgrade support. The revised equation contains new input parameters: resilient modulus, M R, to characterize subgrade support reliability, R to allow the designer to introduce the concept of risk analysis into the design process and standard error, S o, to represent variability in design input values.
The method discussed in the text (Example 20-8) applies to ESALs greater than 50,000 for the performance period. A revised flexible pavement design equation has recently been published by the American Association of State Highway and Transportation Officials. Structural design The object of the design using the AASHTO method is to determine a flexible pavement SN adequate to carry the projected design ESAL.
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