Hello stressers,
In load case : l= WNC+ P1 + H
should I make hanger stiffness rigid or as designed?
thank you

Check this link.

http://65.57.255.42/ubbthreads/ubbthread...=true#Post45350

thank you but this post doesn't answer my question. I have" pipe in -42 C temperature and connected to cryogenic tank and I use spring hanger to make nozzle loads within allowable in operation and design condition but in no content case when I make spring stiffness rigid the load become over allowable, so my question is : should I make spring stiffness in no content case rigid nor as designed ?

When you make the spring rigid, you are forbidding the spring to move, whose sole purpose is to allow your system to pass.

The only time you should make it rigid would be for the original two hanger cases, so that CAESAR can calculate loads by which to size your spring, if indeed you require CAESAR to size it.

The only exception to this I can think of is if you have a transportation case where the spring is to be locked during transport.

Kamal,
If someone is going to lock spring during no content case, you can consider spring as rigid in your analysis. If not, you should consider spring stiffness as design. In some special cases spring needs to be locked during no content event but locking spring exactly when there is no content is practically difficult.

Hello Kamal,

Perhaps you are checking nozzle loads for the erection case when line is empty and spring hangers are locked. But you have also included "P" in the load case, so now I'm confused about the purpose of this load case.

For WNC+P1+H load case you mentioned that "when I make spring stiffness rigid the load become over allowable". This implies to me that line is not properly supported for the weight loads. Perhaps support(s) adjustment to have proper load distribution might help in this case.

You should also run WNC+H with hanger stiffness set to "as designed" to consider for accidental drain post shutdown.