In the Global Settings Tab, under "Rigid Foundation Settings" there is a button for including "Passive Pressure Setting" to use in the check for sliding for isolated footings. This button seems to be "un-checkable" and therefore I cannot use passive pressure in the calculations. I think I can reduce my footing sizes if I could use some of the passive pressure for resistance.
Is there a reason this button is "un-checkable?" Perhaps I need to turn on additional setting? Any information would be helpful.
Thanks!