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For your problem in particular i don't know what to suggest...
If you are study a time domain analyses i can recommend you the books of Wolf about dynamic soil structure interaction:

Foundation vibrationanalysis using simple physical models

Soil-Structure inetaction analysis in time domain

Well, it depends of the kind of problem that you are studing: frequency or time domain, stedy state or time history. There's plenty of text book about the problem, and plenty of symple model to analyse soil-structure interaction model. I use in particular the Lumped parameter model proposed by Wolf,...

I make some simple test, like a year ago, defining 2 material (elastc and one viscous) or a parallel material and for me it works.
Maybe the wrong damping that i observe in my new model came with this problem of parallel material. I try to make a model with 2 material now

In another discussion you say i can model my spring and dashpot sistem with Parallel material command, what is change?

http://opensees.berkeley.edu/community/ ... =2&t=53587

when i use only 1 load i simply delete one of the imposed motion command

This is my model, Rayleigh damping is imposed only in the elastic beam column with region command # -------------------------------------------------------------------------------------------------- # Force=Kn, Lenght=m Kpa=Kn/m^2 Mass=Tonn # SET UP --------------------------------------------------...

Im make this question because i notice some probleme with rayleigh damping in my structure. It seems that if i apply this 2 kind of motion opensees don't take in account the damping. Like i said before i model a linear oscillator, with a lumped parameter model (spring mass and dashpot) at the base t...

I would like to know how Opensees work with 2 different ground motion in 2 different Dof, wich are connected to 2 different vibration mode.
Do Opensees finds the structural response for the first input, after for the second input, and then makes the sum of the two output?

Dear Vesna i have a question,
i must found the acceleration of a simple oscillator applying this 2 motion (X and RY).
Is the same if i firsly found the response only for the X motion, then the response for RY motion and then with a simple sum the response of both the eccitations?

Which command do i use to impose a displacement in 2 direction (for example 1 (for me X) and 5 (Rotation in Y) at the same time??

Thank you for your help!
With this command is possible to impose a rotation just setting the right DoF at the imposedMotion?

Hi, i wuold like to know how to apply a displacement time-history record to a model.
Thanks for any help

Dear Vesna,
My spring and dashpot work in parallel, so i use Parallel material command. I also made a simple model (linear oscillator) and run 2 different zero lenght or only one with parallel material, the results are the same.

Can i assign 2 different zeroLenght element (defining 2 different material -elastic and viscous-) at the same 2 node?

Hello, i'm studiyng the seismic response of a multi span bridge. In my analysis i take great attention to the soil-structures interaction. The simpliest model to study the problem is to substitute the soil under the foundation with a spring and a dashpot. So i have a costant K for the spring and a C...

Hello, i'm studiyng the seismic response of a multi span bridge. In my analysis i take great attention to the soil-structures interaction. The simpliest model to study the problem is to substitute the soil under the foundation with a spring and a dashpot. So i have a costant K for the spring and a C...