dashpot modelling

[meser]

I have a problem with defining dashpot element at the base of my system. I also use a linear link element at the base and running dynamic time history analysis.

1) When I complete the analysis, total base shear of system is a very huge number like 2500-3000 kN, although total base shear seems to be 180-190kN when I remove the dashpot and link element.

2) And displacements are the same in both cases (considering and not considering dashpot) and I am not sure whether the damper is working or not.

Is there a way to be sure that the modelling is true or can you have a look at my system?

Best Regards.

[seismosoft]

The results seem to be consistent with your model, considering that dashpots are fixed to the ground, as explained in the Help System.
The question is, are you sure a dashpot is what you need? What are you trying to model, some sort of damping device? If so, then using a link with an adequate nonlinear response curve, or a link with a linear response curve plus 'element damping' might be a better option.

Seismosoft Support

[meser]

I had already fixed the dashpots and links to the ground as it is written in Help System.The very huge base shear I mentioned was found with this model.
I am trying to do "soil structure interaction analysis" and I want to model soil with horizantal and rocking springs and dampers as it was done in literature previously, that's why I am using link elments and dashpot elements for my system. (The values are
Kx=F1=1940877 kN/m, Kyy=M2=37861651 kNm/rad, Cx=8742 tonne/sec and Cyy=92866 tonne*m^2/sec. These values are obtained based on a study of Wolf et al.)
So what can be the problem or is there a way to overcome?
Best regards.

[seismosoft]

We are not specialists in SSI. However, as we mentioned before, we tend to believe that a linear spring with associated element damping is the most adequate modelling approach.

Seismosoft Support