Governing Equations:

$$ \rho_{\text{center}} = \frac{q \cdot d \cdot I_G \cdot I_F \cdot I_E \cdot (1 - \nu^2)}{E_o} $$

$$ I_F = \frac{\pi}{4} + \frac{1}{4.6 + 10 \cdot K_F} $$

$$ I_E = 1 - \frac{1}{3.5 \cdot \exp(1.22\nu - 0.4) \cdot \left( \frac{d}{z_e} + 1.6 \right)} $$

Useful charts

Figure - Displacement influence factor I_G

References: Mayne and Poulos (1999)