EXJ Spring Rates

How do I specify the limiting spring rates for an expansion joint?

I have allowable nozzle loads that I want to achieve and I have a tentative routing of the piping. I modelled the system without the expansion joints and have the ope case displacements. From this point, is there a way to determine the max allowable spring rates for the expansion joint?

Hi Ryan!!

Well , the first approach should be to avoid expansion joints in your analysis if you can live without it by some modifications of supports, routing etc. Exp joints are not always a welcomed approach as these require some special efforts in maintenance & are expensive too.

However , if you still need expansion joint then just follow this:

a) Based on your piping pressure , pipe dia &service , select an exp joint from a catalogue (you may refer PATHWAY , for eg)

b) Get your displacements to be absorbed in the joint by modelling it in CAESAR using expansion joint using the stiffnesses mentioned in Catalogue against your selected joint by clicking the radio button on Caesar screen & determining the displacements & directions (compression/expansion) & then again re-select your exp joint & no. of covolutions.
c) Don't forget to make an imp selection - joint with tie-rod or without. If your going for the latter , do pass on the thrust loads coming on foundations to Civil.

Hope this is of some help to you.


Thanks!!

SJ
“Smile is the cheapest gift that lasts forever.”