Enter the modulus of soil reaction in psi. Typical values range
from 700 to 1500 psi. Use 700 psi for unknown conditions
(conservative). Use 1000 under traveled surfaces consolidated
over time. Use 1500 for deep pipe in stable soils.
If soil data has been obtained from a site investigation, use
table 5.8 of AWWA Manual of Water Practices M45, Second