How to simulate equipment nozzle subjected to earthquake?

I have a basic doubt:
When a piping system is subjected to earthquake, the actual displacements of the equipment nozzle would be some value in addition to the thermal displacements, as the floor on which this equipment is mounted will also be shaking. This differential would create additional strain in connected pipe. So in this case how shall i accurately simulate the equipment nozzle?
please help.

regards
Ashu chaudhary

this is my third topic in a row which went unanswered.

You can provide two displacement sets for your connection points - one for thermal strain (e.g., D1) and the other for your seismic deflection (e.g., D2). You can combine those as you wish in your load case definitions. That is, even D1+D2 is a legitimate definition of displacements used in the analysis.
By the way, response posted in this forum is voluntary. If you are currently under CAESAR II maintenance, you may also contact your local representative for assistance or file directly in our SmartSupport system.

Thanks Dave for replying.
The method which you have mentioned above will work fine in case i go for static seismic analysis. But in case i go for response spectrum method how can i simulate the seismic deflection of an equipment nozzle? My purpose is to take the effect of the pipe strain into account.


regards

Relative seismic support motion can be included in your response spectrum solution in CAESAR II. Note that I say "relative". If the entire system sees the same shock (or, response spectrum), we assume that all supports move together. In this case there is no relative support strain. In CAESAR II, if you define more than one response spectrum, then the last column in the spectrum definition will be used to collect the displacement for each support in that spectrum group. Be aware that if you define more than one spectrum and do not enter data in this last column, the program will estimate the displacement using response data for the lowest frequency in the spectrum - I do not find this provided number to be what most users expect.

thanks alot Dave.

regards