subgrade reaction for raft design

[ahariri]

given a subgrade reaction of 100 MN/m^3 for a square foot
plate ... is the spring stiffness 100 x the trib area of the join it is assigned to (in a computer model)?
thx

 

[DaveAtkins]

I cannot easily determine the answer to your question, because you are mixing metric and English units. When in doubt, I like to remember the actual definition of modulus of subgrade reaction: k = 100 MN/m^3 means a 100 MN load on one square meter of soil will compress the soil one meter. Modulus of subgrade reaction is easier to understand if you denote it 100 MN/m^2/m instead of 100 MN/m^3. DaveAtkins