RISAFoot FAQ

Why doesn’t my hand calculation of the overturning moment match the overturning moment given by RISAFoot?

Traditional hand calculations use a method that assumes that all vertical loads are stabilizing loads that are only capable of producing a stabilizing moment and all lateral shear and moments will act to de-stabilize the structure. For example in a hand calculation, the axial forces from both dead loads and wind loads are combined to form a total vertical load. RISAFoot uses a method that involves taking a look at every component of every load and deciding whether it has a stabilizing or de-stabilizing effect. For a more detailed example, see Stability under the Help menu.

How do transfer my reactions from RISA-3D to RISAFoot?

The footing design will take place entirely inside RISA-3D. If you have RISAFoot license, you will see that RISA-3D has Footing Definitions tab on the Data Entry toolbar where you can create your footings. You will also be able to place a footing at any boundary condition once you have footings defined.

How is the rebar designed for my pedestal?

My footing has uplift, why isn’t RISAFoot providing top steel?

Version 2.0a of RISAFoot calculates the negative moment caused by overburden and slab self weight. If that moment exceeds the flexural strength of the plain concrete section (per section 22.5 of ACI), then top steel will be added to resist the negative moment.