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This is calculated from the dimensions of the assumed punching shear perimeter.

For further discussion and equations refer to Chapter 13-8 of the Reinforced Concrete Mechanics and Design textbook by MacGregor & Wight.

For edge and corner cases this value is calculated as the moment of area of the shear perimeter/area of the sides. For an interior punching shear perimeter this will always be L1/2 or L2/2. These give the distance from the shear perimeter edge to the centroid of the shear perimeter.

For further discussion and equations refer ACI 318-14 Section 48.4.4.2.3 (ACI 318-11 Section R11.11.7.2) and Chapter 13-8 of the Reinforced Concrete Mechanics and Design textbook by MacGregor & Wight.

This calculation is very different depending on interior, edge or corner punching shear cases.

This value is used to determine the shear stress in the critical location due to unbalanced moment. This is a property (Jc) of the critical section which is analogous to polar moment of inertia about the local yy axes.

For further discussion refer to ACI section 11.12.1.2 and 13.5.3.

This value is used to define the punching shear perimeter as well as to define how much of the moment is transferred by eccentricity of shear (as opposed to the portion transferred by flexure). Length of the critical section along the local axes.

In cases where no design strips are defined at the pedestal location, the program will assume the bar size and cover specified in the first rule defined in the Design Rules spreadsheet. The effective depth is based on the smallest depth to centroid of reinforcing for the Design Strips that encompass the pedestal. The effective depth of the slab is used to define the punching shear perimeter at a distance of d/2 beyond the edge of the column/pedestal. Punching Shear Calculation Values Effective Depth, d The applied shears and moments, along with the shape of the punching shear failure cone are used to calculate a maximum punching shear stress. Thus, a stress demand/stress approach is taken.

This works if only shear force is present, but is insufficient if a moment is occurring on the column/pedestal. Many hand calculations will consider a punching shear force against a punching shear capacity force. Punching shear calculations require a demand value and a capacity value. Punching shear is a phenomenon where a concentrated force on a slab causes a shear failure cone that 'punches' through. Here is some information on those calculations. Punching shear calculations are provided for columns/pedestals that land on concrete slabs. Punching Shear - Design Punching Shear - Design

Sam the ultimate mechanism designer crack