stiffness of gusset plate ( Hsiao )

[nilz]

Hi Dear Terzic,
Has anyone used the equation of gusset plate stiffness which is provided by Hsiao et.all(Improved analytical model for special concentrically braced frames)?
1-How can calculate its parameters?
2-In chevron braced frame, are there any differences between the applied calculation method of midspan (top) gusset stiffness and the one used for the bottom gusset stiffness?
If so, what is it?
3-For modeling the chevron braced frame midspan gusset in Opensees Should a specific parameter be considered or it is similar to the bottom gusset plate?
I look forward to hearing from you