SFA doesn't consider the contribution of the supporting soil for punching shear checks?
I mean what happens if the foundation is on rock?
SFA = STAAD FOUNDATION ADVANCED
STAAD Foundation Advanced does consider the contribution of the soil when calculating punching shear force.
In general, it calculates the punching shear as A minus B
where
A = Downward force on the foundation due to the axial compressive force in the column
B = upward resistance due to the pressure at the base of the footing on an area equal to that bounded within the punching perimeter
Term "B" depends solely on the pressure on the soil due to the loads from the column. It does not depend on the bearing capacity of the soil. In other words, it does not matter whether the soil beneath the footing is clay, sand, or a hard medium like rock or basalt.
For the US code (ACI 318), there is a special requirement in Section 11.11.7 of the code that causes a term called unbalanced moment to contribute an extra force that may add to or subtract from the punching force calculated using the aforementioned formula.