I am trying to understand and set up load cases in Caesar-II for a static-equivalent seismic analysis in compliance with ASME B31Ea-2010.

I contacted the Hexagon help team and exchanged emails with Denny Thomas, but I am still seeking some more detailed/in-depth guidance for how to approach the Load Cases for ASME B31E Para. 3.4

Specifically, I am confused about how to obtain the M_seismic value in the first equation, PD/4t + 0.75i * (M_sus + M_seismic)/Z.

M_seismic is the "elastically calculated resultant moment amplitude due to seismic load, including inertia and relative anchor movement"

In order to isolate the inertial (U1, -U1, U2, U3, -U3) and the SAM (D1, -D1, D2, -D2), do I need to build an operating case for EVERY POSSIBLE COMBINATION OF THESE CASES, then subtract out the OPE cases? Or is it possible to do this in fewer steps? Are any of these cases redundant, or could they all produce relevant values?

L1: W+P+T (OPE)
L2: W+P+T+U1 (OPE w/ inertia cases)
L3: W+P+T-U1
L4: W+P+T+U2
L5: W+P+T+U3
L6: W+P+T-U3
L7: W+P+T+U1+D1 (ope w/ inertia + sam cases)
L8: W+P+T+U1-D1
L9: W+P+T+U1+D2
L10: W+P+T+U1-D2
L11: W+P+T+U1+D3
[...] ADD ALL -U1, U2, U3, -U3 CASES
L20: L2-L1 (isolated inertia cases)
L21: L3-L1
[...]
L26: L7-L2 (isolate SAM cases)
L27: L8-L2
L28: L9-L2
[...]

I will spare you the very long list of possible cases. The confusion sets in when trying to isolate the displacement cases. There will be an isolated "D1" case for U1, -U1, U2, U3, and -U3 cases. I could do a MAX operation on those, but are any of them redundant, or is there a quicker way to do this?

The very basics in SAM analysis is that the relative displacements at the supports are considered and they are obtained from the structural response calculations. Once calculated they are imposed on the supported items in the (still realistic) most unfavorable conditions.

Thanks, Mario. In the context of your response; what is the best method to set up load cases to determine the most unfavorable conditions?

Can [OPE + U(i)] inertia cases and [OPE + D(i)] SAM cases be run separately, then combined using SRSS and added to one another?

Or do the displacement cases (D) need to be considered in OPE cases including inertia (U) and algebraically, individually subtracted out before combining using SRRS?

Steven,

Your question about "the best method" is hard because often what you think is the best may be in contradiction with what a Code imposes.
A good question is what B31Ea considered as appropriate in their 3.4 "Design by analysis".
What they said in 3.1 is that "the seismic loading shall be specified for each of three orthogonal directions" combined by SRSS or using an alternative method (envelope of the SRSS E-W+Vertical and N-S+Vertical). There is an warning about including in-structure amplification of the free- field acceleration by the structure as seismic loading applied to piping systems and no clue about SAM. At least it seems clear that SRSS is applied for effects of "seismic loading" in three orthogonal directions- to comment your proposals.
Without B31Ea support for "seismic loading" applied in one direction, there is the temptation to absolutely combine the inertial response and the pseudostatic response (peak group displacements occurring at the same moment, combined in the most unfavorable way to calculate SAM component of the seismic response). The problem is this approach "can considerably overestimate the seismic response when compared to time- history".
NUREG-1061, volume 4 (reference https://www.nrc.gov/docs/ML1134/ML11343A034.pdf ) gives you what they consider as better alternatives. You can find the document on internet and study.

BR,
M