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It may be that you don't have the at2 ground motion file in the correct folder.

You can record the stress and strain at one of the fibers in your section that has the concreteCM material.

Please see the example at the bottom of this link here: https://opensees.berkeley.edu/wiki/inde ... t_Recorder

To eliminate the possibility that unit change leads to other changes in your tcl file and the model, could you check the initial slope of the resulting moment curvature in both cases.

Are you modeling the nonlinear dashpot in Matlab? If you are not, the difference could be because of that

There is a bond slip material that is available to model the slip between rebars and concrete. You can explore if you can use this somehow to model the slip between concrete and the steel tube: https://opensees.berkeley.edu/wiki/index.php/Bond_SP01_-_-_Strain_Penetration_Model_for_Fully_Anchored_Ste...

You can try directly using the rigid link command instead of a rigid element

https://opensees.berkeley.edu/wiki/inde ... nk_command

If your viscous material has a linear force-velocity relation, i.e. f=Cv, you can just use mass proportional damping

You can try using Reinforcing Steel material. Another option is to determine the collapse point during postprocessing

Is the pushiver analysis completed? You can add an exit command to the very bottom of your script and see if there is data in the recorder output files

Yes that looks right. Let's see how your results look like when you include that.

The solution in the first post looks like a reasonable solution. Or instead of modeling a fiber section, you can compute the moment-curvature relation of the beam offline and assign it to your section.

The results should change I think. Could you try replacing the Bouc-Wen with an elastic material and see if the results change when you change the parameters?

You need to define the Bouc-wen material as a unizxialmaterial and assign it to your zerolength element

https://opensees.berkeley.edu/wiki/inde ... n_Material
https://opensees.berkeley.edu/wiki/inde ... th_Element

You can apply the vertical gravity forces only at the first floor nodes

It should, but you can make the same stress-strain checks for the fibers of the section at the top end of the column and the beam end. If you are using a constraint that sets the elongation/shortening of the beam to be zero, that has an unintended consequence of introducing axial force on the beam s...