What are the units for the columns 2: Translation & Rotation In the AutoPIPE Mode shape output report?
There are no actual displacements, it just a shape with any amplitude, positive or negative.
Modal Displacements (or mode shapes, they are one and the same) are mass normalized in AutoPIPE. There are no modal stresses.
Modal analysis is a requirement for all dynamic analysis in AutoPIPE, such as response spectrum, time history, force spectrum and harmonic loads. These analyses will have true displacements and true stresses. Modal displacements are not true displacements and that is why they are commonly normalized to 1 or mass normalized.
Mode shapes or resonance shapes or natural vibration shapes are real and when a system is excited it most likely will vibrate in one or a combination of many mode shapes. It all depends on the loading pattern and loading frequency.
"Mode Shape" sub report
Bentley AutoPIPE