Module 4: Pavement Design
Lecture 29 Rigid pavement design

Wheel load stresses - Westergaard's stress equation

The cement concrete slab is assumed to be homogeneous and to have uniform elastic properties with vertical sub-grade reaction being proportional to the deflection. Westergaard developed relationships for the stress at interior, edge and corner regions, denoted as $\sigma_i,~\sigma_e,~\sigma_c$ in kg/cm$^2$ respectively and given by the equation 1-3.
\end{displaymath} (1)

\end{displaymath} (2)

\end{displaymath} (3)

where $h$ is the slab thickness in cm, $P$ is the wheel load in kg, $a$ is the radius of the wheel load distribution in cm, $l$ the radius of the relative stiffness in cm and $b$ is the radius of the resisting section in cm
Figure 1: Critical stress locations