Concrete Damaged Plasticity

Hi, I am currently trying to model a RC connection and I am using Concrete Damaged Plasticity, CDP, to model my concrete. WIthin this model, you would need to specify the tension damaged against strain or displacement. I have looked through the literature, there are many papers that talk about the damage, but they do not show how the tension damage was obtained.

There is an example in Abaqus, seismic analysis of a gravity dam. In this example, the tension damage vs displacement was entered. I looked through the citations but i could not figure out where the tension damage was obtained.

Is this parameter only obtainable through material test? Can someone help to enlighten me?

Thanks!

Best Regards,

Joseph