Conditional Partial Fixity of Truss Joints

[SASteve]

Hi there,

I am trying to model wood roof truss systems, and I am wondering if there is a way, in V18, to model "truss" joints with partial fixity (applying empirical joint axial stiffnesses) to be applied only when the members are in tension.

Assuming that there is no gap between members, I would like to model contact reactions between members in compression as rigid joints.

If anyone could tell me whether it is possible to model conditional partial fixity, that would be awesome.

Thanks