Question about SCBF example of Discoveriong OpenSees

[AbRiahi]

Hi everybody
I have just studied "Modeling SCB frames using beam-column elements" that is one of the examples of "Discovering OpenSees" but I have some questions:
1) about the parameters using to simulate fatigue in the braces I see that the adopted values for $E0 and $m are based on the calibration done by Uriz et al., But what is the source of adopting $min=-1.0 & $max=0.04?
2) Can Corotational geometric transformation can be used for beam and column elements as well (like the braces)? If yes, Why is the reason of choosing P-Delta geometric transformation for that elements?
3) What is the advantage of defining Rigid truss elements over using equalDOF command to assure that the beam nodes move horizontaly together?
4) Don't we need to assign the load pattern to all the nodes on the same level for the pushover analysis? (I mean assigning load pattern for node 4 like nodes 3 and 5)