AASHTO 1993 Flexible Pavement Design Calculator

Design Parameters

Design ESALs (W₁₈)

Reliability (R) [%]

Overall Standard Deviation (S_o)

Initial Serviceability (p_i)

Terminal Serviceability (p_t)

Subgrade Resilient Modulus (M_R) [psi]

Structural Layer Coefficients

Surface Layer (a₁)

Surface Depth (D₁) [in]

Base Layer (a₂)

Base Drainage (m₂)

Base Depth (D₂) [in]

Subbase Layer (a₃)

Subbase Drainage (m₃)

Note: The required SN is solved using the Bisection method to find the root of the AASHTO 1993 empirical equation. The required subbase depth (D₃) is computed so that the provided SN equals the required SN.

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