Procedure for Design

1. Determine footing plan geometry based on loading, self weight of the footing, weight of soil on top of footing, buoyant forces based on water level, and bearing resistance of the soil.

   The stress distribution under the footing is assumed to be linear. For eccentrically loaded footings, the stresses may become tensile under part of the foundation. In such cases, the program sets stress values in uplift zones to zero and calculates new values elsewhere for the revised equilibrium condition. Stability checks in both orthogonal directions are performed. The final plan dimensions of the footing are established iteratively from the condition that the maximum stress should not exceed the factored bearing resistance of the soil.

2. Development length is checked for straight rebar. If development criterion is not met by the footing geometry a warning message is displayed in the calculation sheet, user can go for other detailing options like bent bars.

Calculate footing thickness based on structural capacity in shear and bending.

Capacity Checks

Structural design of the footing consists of the following:

• Punching shear check, in accordance with ACI 318 Section 11.12.2 (for US jobs), at a distance of d/2 from the pedestal. The critical section comprises four straight-line segments, parallel to the corresponding sides of the pedestal.
• One-way shear (beam action), in accordance with Sections 11.1 through 11.5, at a distance of d from the face of the pedestal, in both orthogonal directions. The critical plane is assumed to extend over the entire width/length of the footing.
• Bending, in accordance with ACI 318 Sections 15.4.2 and 10.3.4 (for US jobs), with the critical planes located at both orthogonal faces of the pedestal and extending across the full width/length of the footing.

Design output displays applicable code sections used for foundation design for all codes.