Hi All,

I am trying to impose the structure horizontal seismic displacements (input data from civil works) by means of CNodes at those supports where the pipe is linked to the structure in earthquake events, that is, lateral and axial pipe supports.

When the pipe routing is paralell to the global axis it seems CAESAR works OK. However, in case of being the piping line out of the global axis it seems CAESAR does not take into account the displacements imposed by CNodes. Moreover CAESAR overrides the restraint reporting zero loads and displacements different from the imposed ones.

On the other hand, I am not sure if I have combined correctly the loads. First I have combined operating cases with each seismic vectors and each structure displacement vectors. Then I have subtracted each occasional load (seismic and displacement vectors). Seismic vectors have been combined by SRSS and in another load case the displacement vectors have been added. This last load case has been used to check both stresses (with sustained case) and loads (with operating case) at restraints.

Any feedback will be welcome.

Thanks a lot!!!

Only guessing...
If I define an X restraint (with no friction) in CAESAR II with a CNode and then specify seismic displacements on the CNode, only X displacements will find their way to the pipe. Any CNode Z displacements would not be transferred through an X restraint.