I'm designing a mat footing. Does anyone know how to calculate the values for R,S,Z force constants?
See the frequently asked question "What value should I use for the area springs Z force constant?" for discussion on the vertical spring constant:
RAM Concept Modeling Mat Foundations FAQ
For R and S, I would use a very weak spring (0.1 pci) to provide some nominal translational restraint. This technique is also used in the mat foundation tutorial in the RAM Concept Manual (Help - Manual - Chapter 50).
Answer Verified By: Karthik Madhur