Dear sir

I need to use joint2d element on opensees platform to define connection between beams and columns connection in RC frames.

I have got two questions, first is it necessary to assign pinching4 material for joint element?

How can I calibrate and define different parameters for pinching4 material?

Could you recommend a book or approapriate reference to define and calibrate pinching4 material?

I will really appreciate your help if you can help me.

Thank you.