Dear Colleagues,

I'm trying to make a model of RC prefabricated structure using ETABS software's link elements to model the connection between the elements.
The links are multi-linear plastic with non-linear force-displacement relationship for U1 and U2 directions.
The U2 direction represents the Coulomb friction relationship depending on the compressive axial force in the U1 direction.
When the axial force becomes positive, the stiffness in U2 direction must be 0.
I'm puzzled and can't figure out how to make a coupled DOF in U1 and U2 directions so that U2 direction stiffness is proportional to the axial force in U1 direction in compression and equals 0 when U1 is in tension.

I would appreciate any suggestions and advice.

Thanks in advance.