I'm working on wellhead platform. There is request from client to consider structure displacements into calculation.

My question:

In case of earthquake event, should earthquake acceleration (in g) and structure displacements (due to earthquake) impose on pipe supports be considered together? Purpose is to check nozzle load, flange leakage and support loads.

For example:
LC1: W+T1+P1+U1+D1 (OPE)
LC2: W+T1+P1+U2+D2 (OPE)

T1 = operating temperature
P1 = operating pressure
U1 = earthquake acceleration in +X
D1 = displacements due to U1 impose on pipe supports in +X
U2 = earthquake acceleration in +Y
D2 = displacements due to U2 impose on pipe supports in +Y

Any advise is appreciate.