Dear Seok,

It is not correct to model the changes due to allignment as displacements imposed on the piping because they are not.
The piping system after the allignment procedure has been carried out should represent your CAESAR model.
Also, you are implying that allignment-related changes may equal the small spring travel, that is why you are saying that an adjustable support may be used instead of a spring.
I think you should remember that,
1. Small changes due to allignment is done while the pump is not running.
2. Small spring travel is required when the pump is running.
Are you willing to monitor and adjust the adjustable support as the pump piping goes through temperature changes? If yes, how are you going to make the adjustment at the exact moment the adjustment is needed?
Just my opinion.