How to implement hinge boundary condition in Opensees

[CorporalToe]

I am trying to simulate a frame where the beams are connected to the columns via hinges. I have it working as rigid connection but I do not know how to add releases for the moments.

 

[a_urbs]

You could make 2 nodes at the same point, and define a zero-length element with stiff x and y properties and no rotational stiffness. I did something similar for a project with RBS connections, instead of 0 rotational stiffness, the rotational stiffness was based on the hysteretic behaviour of the RBS hinge.

I'm sure there are other ways to do it but that's what came to me.