Well, the rotation of the bearing may be assessed by making use of the inner pad material properties. AASHTO gives formulas for the rotational limits and from this you can find the rotation springs to emulate this behavior.
As for translation there are two types: those that allow translation and those that don't. When translation is accomodated it is usually with a tongue and groove PTFE/mirror interface. The only constraint here is the frictional force. Once you overcome that, it moves and the restraint is removed - which makes this analysis an iterative one. Frictional values for PTFE surfaces can be found in AASHTO or other bearing references.