Below is a couple of questions about modeling rigid zones:
1) The beam-column joint in monolithic construction shall be represented as a stiff or rigid zone having horizontal dimensions equal to the column cross-sectional dimensions and vertical dimension equal to the beam depth, except that a wider joint shall be permitted where the beam is wider than the column and where justified by experimental evidence (ASCE 41-06 Section 6.4.2.1). In a special moment frame (SMF) the beam-column joint is stiffer than the adjoining beams and columns, but it is not perfectly rigid. As described above, the joint stiffness can be adequately modeled by extending the beam flexibility (0% percent rigid) to the column centerline and defining the column offset as 100% rigid within the joint (p. 7, Moehle et al., 2008).
As per the discussion/description above, what is the appropriate method to model beam as 0% rigid and column as 100% rigid? Cardinal point method (1st method) or rigid end offset method (2nd method)?
2) As per the discussion in RAM Elements manual, the second method considers rigid end offsets in the three directions of the global axes. However, the label of the command bottom says "Create axial rigid end offset". This seems very confusing, since the user might thought that only the axial direction is being considered as rigid.
3) For accounting panel zone deformation in the model, what's the appropriate method?
If possible, please answer by item.
Thanks!
