problem with BasicDeformation

[sabir]

Hi dear Vesna/Silvia
I have an 7 stories steel model (MRF)
i want to calculate the maximum rotation in beams and columns, i want to calculate the ductility of elements, i use the nonlinear time history analysis.
i used the following recorder: recorder EnvelopeElement -file $file/col10rotation.out -ele 10 basicDeformation
but the results are very incredible!!! for example in one of the columns of the top story i have the maximum rotation about: 0.0273941 while the yield rotation in this element equal: 6.639E-04 how it is possible?
in the lower story the maximum rotation about: 0.0379 while the yield rotation in this element equal:2.650E-03
the ratio of D=ROTmax/ROTy for top story equal 4.127E+01 and for lower story equal 1.430E+01. are this results credible? I'm confused?? please help me.
My advoisor suggest me to evaluate the curvature and then multiply that to the plastic length for Rotation evaluation? is it true?
How i can calculate the plastic length ? the Opensees can calculate the plastic length?
impatiently wait for your reply.
Regards