Q: Why when I check a cylindrical member subjected to combined hydrostatic pressure, axial tension and bending manually do I get a different RP2A unity ratio than MOSES?
REV 6.02

A: According to RP2A, the following equation should be satisfied in this case:

A**2+B**2+2*ν*|A|*B≤1   (3.3.3-1)

Since the equations 3.3.1-2 and 3.3.3-1 check the same thing we take a square root here in order to be consistent and get unity ratios closer to those of 3.3.1-2. when a zero hoop stress is applied. Notice that this change does not effect whether or not a member satisfies the code.