I want to model a tied expansion joint in CAESAR II. For this, I am using CAESAR II expansion joint modeller using Piping technology catalogue. Now as per my knowledge, a tied EJ doesnt allow axial movement. And to model this behaviour, the program puts a rigid element. But simulaneously, I observed that the axial stiffness value is very less as compared to the other stiffnesses.

Does this affect the behaviour of tied EJ modelled along the axis?

Please comment.

The axial stiffness is the value for the axial direction of the bellows, from the catalog. The reason that the tied-EJ doesn't allow axial movement is because of the tie-bars, which CAESAR II has modeled as the "rigid element".