RAM Concept investigates the slab geometry within the punching zone radius specified to find likely failure locations. RAM Concept ’s critical section calculations correctly consider slab thicknesses, but make simplifying assumptions about the elevations of the slab regions. In certain situations this can result in improper location of critical sections.

In areas of varying thickness, RAM Concept 's punching calculations assume that the thickenings protrude toward the load application. For example, in an elevated slab shear caps are assumed to be located below the slab, and in a mat/raft foundation plinths are assumed to be located above the mat/raft. If this is not the case, RAM Concept may not locate the critical sections appropriately. See the example in the following figure.

The location at some distance (usually a function of effective depth "d") from the face of the column is considered to be a likely failure area. The location at some distance from a change in section thickness is also considered to be a likely failure area.

If the slab edge/hole treatment is set to Sector Voids, then any slab edge or hole found within the punching zone radius creates a sector or zone that offers no resistance to punching.

If the slab edge/hole treatment is set to Failure Planes, then RAM Concept investigates a number of critical sections including sections that connect to edges or openings (which provide no punching resistance) in attempts to find the most critical section.

If the slab edge/hole treatment is set to Ignore Edges, then the location of the critical sections is not affected by the holes, but any part of a section intersecting a hole will be considered to provide no punching resistance. It is recommended that Ignore Edges is only used if the Sector Voids and Failure Planes treatments do not produce desired critical sections.

RAM Concept tries to connect the likely failure locations together to determine logical potentially critical sections. The method that RAM Concept uses tends to find the appropriate sections, but does not always find them. You should always visually inspect the locations of the critical sections that RAM Concept has checked to see if they are appropriate (this is usually accomplished by a simple visual review of the Design Status: Punching Shear Status Plan).