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An explicit moment-axial force interaction curve cannot be input in OpenSees, how do you consider that? That may be the reason of the difference. Because you have differences in the pre-yield results, you might be having some other geometry differences as well. Please post your curves both for 2D an...

Do you define any moment-axial force interaction in SAP2000? Are you getting similar curves before yield?

It is the latter one, i.e. the trasversal dof and it gets the axial force from column that it is connected. The connected column info is provided as input.

Great! Let us know if you have other problems or questions.

You need to use a zerolength element and assign these materials to the element. Please remove the section Aggregator and let me know if you have any difficulties.

http://opensees.berkeley.edu/wiki/index ... th_Element

Are you trying to simulate the local buckling?

Please check if the stiffness of your 2D model is really half of the stiffness of the 3D model. You can simply do that by applying lateral force to the top floor in the linear elastic range in both models.

You don't need to assign a rigid diaphragm in the 2D model. Axial stiffness of the beams are generally high enough to represent the rigid diaphragm condition. Why do you add additional mass to your joints while converting your model from 3D to 2D? That may be the reason of substantially increased pe...

You can only get the moment-curvature relationship (not the moment rotation) from the zero length section element. For the rotation, you need to convert the curvatures to rotations over a plastic hinge length.

Could you quickly check which column is which.

1) By applying axial force only with zero moment.
2) By applying moment only in the elastic range with zero axial force (Cur=M/EI in this case).

A graduate student who is quite experienced with steel shear wall modeling indicated that the current methodology is to use strip model with corotational truss and an appropriate material property (you can use Steel02). For more information about the strip model, please refer to "Design Guide 20: St...

Did you make sure all your units are consistent? You should calculate Iz as bh^3/12 and not as (bh/12)*(b^2+h^2).

Have you tried using a rigid end offset to consider the length of the wall? Below is a syntax to do this for Linear Transformation

geomTransf Linear $transfTag $vecxzX $vecxzY $vecxzZ <-jntOffset $dXi $dYi $dZi $dXj $dYj $dZj>

Two questions and a comment: 1. Are you using a rigid diaphragm in the ETABS model? 2. Are you modeling only one of the NS frames in the 2D model? 3. It looks like you are having inconsistent periods from the 3D and 2D ETABS models as well. So the problem looks like it is not related to the Fiber se...

We have previously developed a shear spring that considers the shear capacity-axial force interaction according to the Caltrans SDC and ACI318 equations. You can find the details in Chapter 6.2 of the report below. Please let me know if you have any questions. http://peer.berkeley.edu/publications/p...