Hi all,
Stiffness modifier can be found under "Effective Stiffness" in ATC40 or FEMA356. What I remember are 0.7 and 0.5 for flexural of column and beam, respectively, and 0.5 for shear of column/beam. However, 0.7 of flexural modifier value could produce underestimate deformation result. To approach more closely, you can use program i.e. XTRACT, RESPONSE2000 or CUMBIA (for free but Matlab script). By program you may find effective stiffness up to 0.3 for column.
Cheers
adekajeng
Stiffness modifier can be found under "Effective Stiffness" in ATC40 or FEMA356. What I remember are 0.7 and 0.5 for flexural of column and beam, respectively, and 0.5 for shear of column/beam. However, 0.7 of flexural modifier value could produce underestimate deformation result. To approach more closely, you can use program i.e. XTRACT, RESPONSE2000 or CUMBIA (for free but Matlab script). By program you may find effective stiffness up to 0.3 for column.
Cheers
adekajeng
.