When performing a Safety analysis with a Target Factor of Safety (ΣMsf), the calculation will first pass the target value to ensure that this ΣMsf value is a “stable” value before returning to the specified target value, see also the related article for more background information.
However, in PLAXIS 3D 2013, when the calculation jumps back to the calculation step prior to reaching the target value, the force values in the beams and embedded piles are not (re)set to this calculation step (point C in the image below), but are still taken from the step with a higher ΣMsf (point B) before performing the final calculation step (point D). As a result the forces in the beams and embedded piles are not correct for this final step of the Safety analysis with a Target ΣMsf.
This issue is now solved for PLAXIS 3D AE.00.
For older versions, some work arounds are mentioned below:
To find the correct forces in a beam or embedded pile, the step in which the value for ΣMsf is equal to the value for the Target ΣMsf should be manually determined and then inspected: when necessary recalculate the phase and make sure to save all steps by setting the Max number of steps stored equal to the number of Additional steps.
To continue phases from this situation with the correct value of ΣMsf: