When engineers design flat slabs by hand, they often ignore the one-way checks. They decide that punching is all that is appropriate. (This is often decided without much consideration – it just "seems right").

RAM Concept does not make this decision, as nowhere does the code advise to ignore one-way shear checks in a flat slab or flat plate. Nonetheless, you should decide what the possible failure mechanism is and so what is appropriate. It may, or may not, be appropriate to ignore the one-way shear results. For example, columns C in the previous two figures are satisfactory for punching shear (without reinforcement) but the mathematics of the code requires one-way shear reinforcement. It is up to you to decide if this is appropriate.

This is likely to be a shear core issue. Refer to About shear core and Shear core in slabs .

For a post-tensioned beam, the reason could be that RAM Concept is deducting a fraction of the (bonded) duct from the web width per the appropriate code rules.

RAM Concept calculates the number of duct by dividing the Strands per tendon by the Max strands per duct (as specified in the Materials) and rounding up to the next integer.

Refer to the following sections for an explanation of RAM Concept ’s shear web calculation:

• For AS 3600, Section 8.2 Shear Design
• For BS 8110, Section 3.4.5 Design shear resistance of beams .
• For IS 456, Section 22.4 Design shear resistance of beams .
• For EC2, Section 6.2 Design shear resistance .
• For CSA A23.3, Section 11.3 Shear Resistance of Beams

The is likely a combination of two things:

• there is net compression force and a small moment, and as such the bending designer does not provide any reinforcement
• the minimum designer has been turned off

If this is the case, you should consider turning the minimum designer back on.