The most frequent usage of vestigial resistance is for prestressed members where is important to know the reserve to maximal capacity of the subjected member for the combination N+M+M.
You can use the following inequation for axial force.
The left-hand side of the inequality contains the external load and the right-hand side of the resistance. Generally, the right-hand side then contains the primary effects resulting from the decompression prestressing force and the effects of the vestigial resistance of the prestressing reinforcement.
As a consequence of this, you cannot find prestressing force P on the side of outer loads in IDEA StatiCa. It' being seen in the following tab.
N0pp stands for primary force causing decompression stress in prestressed reinforcement
NEd stands for external load – in this case, the external load was equal to zero