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
in kg/cm respectively
and given by the equation 1-3.

(1)

(2)

(3)

where is the slab thickness in cm, is the wheel load in kg, is the
radius of the wheel load distribution in cm, the radius of the relative
stiffness in cm and is the radius of the resisting
section in cm