Structural Design

The goal of structural design is to determine the number, material composition and thickness of the different layers within a pavement structure required to accommodate a given loading regime. This includes the surface course as well as any underlying base or subbase layers. This module is focused on the structural design of new pavement. Structural design for rehabilitation is covered in the Rehabilitation Module.

For HMA pavements, structural design is mainly concerned with determining appropriate layer thickness and composition. Calculations are chiefly concerned with traffic loading stresses; other environmentally related stresses (such as temperature) are accounted for in mix design. The two principal methods of HMA pavement structural design in use today, empirical and mechanistic-empirical, are covered.


For PCC pavements, structural design is mainly concerned with determining the appropriate slab thickness based on traffic loads and underlying material properties, and joint design. This is done by considering a variety of stresses which affect rigid pavement performance: curling (temperature stresses), warping (moisture stresses), wheel load and shrinkage/expansion. The two principal methods of rigid pavement structural design in use today, empirical and mechanistic-empirical, are covered.

Overall, this Module is only meant to provide a brief overview of the different structural design techniques as well as their assumptions, inputs and outputs. Detailed analysis of the design methods presented here can be found in:


Suggested Reading

  • American Association of State Highway and Transportation Officials (AASHTO). (1993). AASHTO Guide for Design of Pavement Structures. American Association of State Highway and Transportation Officials. Washington, D.C.
  • The Asphalt Institute. (1999). Thickness Design – Asphalt, Manual Series No. 1. The Asphalt Institute. Lexington, KY.
  • Asphalt Pavement Alliance (2002). Perpetual Pavements: A Synthesis. Asphalt Pavement Alliance. Lanham, MD. http://www.asphaltalliance.com. Accessed 7 August 2002.

Publications Cited

  • Highway Research Board. (1961). The AASHO Road Test: Report 1, History and Description of the Project. Special Report 61A. Highway Research Board, National Academy of Sciences. Washington, D.C.
  • Mahoney, J.P. (December 2001). Study of Long-Lasting Pavements in Washington State. Perpetual Bituminous Pavements. Transportation Research Circular No. 503. Transportation Research Board, National Research Council. Washington, D.C. pp. 88-95.
  • Transportation Research Board (TRB). (2001). Perpetual Bituminous Pavements. Transportation Research Circular No. 503. Transportation Research Board, National Research Council. Washington, D.C. http://www.asphaltalliance.com. Accessed 7 August 2002.