Seismosoft | Earthquake Engineering Solutions

Dear sir/madam
It will be appreciated if help me have answer to following question:

1- In a viscousally damped frame, there is a phase shift between
story shear and story overturning moment, since under an
earthquake motion, column axial forces are proportional to the
story overturning moment (i.e. absolute acceleration), and column
shear and bending moment are proportional to the frame
deformation (i.e. pseudo acceleration), there will be a phase
shift between column axial force and column bending moment (or
shear force). I have built several model of high viscousally
damped fame but did not observe any phase shift, what is the
reason?

Best regards
Payman

Dear Payman,

We are not sure we understand fully your kind query, as we are also not convinced that this Forum constitutes the right venue for the somewhat conceptual discussion you have raised.

In any case, we do not quite understand why should there be a phase shift between story shear and story overturning moment, since these response quantities are all related to one and other, hence the results you have obtained seem quite normal to us.

Kind regards,

Seismosoft Support

Dear sir/madam
Respectively refer you to follow article :
"Comparative Study of Frames using Viscoelastic and Viscous Dampers"
by Yaomin Fu, (Visiting Res., Dept. of Civ. Engrg., Univ. of British Columbia, Vancouver, Canada) and Kazuhiko Kasai, M.ASCE, (Prof., Struct. Engrg. Res. Ctr., Tokyo Inst. of Technol., Nagatsuta, Midori Ku, Yokohama, Japan; currently at ATLSS Ctr., Lehigh Univ., Bethlehem, PA 18015)
Journal of Structural Engineering, Vol. 124, No. 5, May 1998, pp. 513-552, (doi 10.1061/(ASCE)0733-9445(1998)124:5(513))

Kind Regards
Payman