Fix Uz during OOP URM shear wall analysis

[kesavapraba]

Dear Sir/Madam
I am not able to clearly understand the reason why Fix Uz (sp) condition is applied after vertical analysis. I watched the tutorial video, still unable to grasp it. LoadConst is specified at the end of the vertical analysis and EqualDOF (mp) is also assigned for Uz in the first stage of the analysis. Are those conditions not sufficient to maintain the Uz during the second stage of the analysis, i.e., OOP horizontal analysis. Why is that extra Uz fix with relative option needed? I have given the time-stamp of the point of discussion in the link below. Can you kindly explain it further?
https://youtu.be/m65mJq6Uce8?t=4728
Additionally, if I want add another stage of analysis in continuation of the vertical and OOP analysis along the IP direction (i.e., keeping the vertical and OOP analysis locked in the current stage) what extra condition should I consider?
Thank you

[STKO Team]

I am not able to clearly understand the reason why Fix Uz (sp) condition is applied after vertical analysis.

Because in the experimental test I wanted to simulate, they were fixing the Uz displacement at the value attained at the end of the vertical analysis.

LoadConst is specified at the end of the vertical analysis

This is only required to keep all the previous loads constant, otherwise, when you change the time back to 0, their timeSeries will give another load multiplier...

EqualDOF (mp) is also assigned for Uz in the first stage of the analysis. Are those conditions not sufficient to maintain the Uz during the second stage of the analysis

No, the EqualDOF is just saying that all the nodes constrained in the EqualDOF will move of the same ammount, but they will not necessarily remain fixed at the current location. Saying that they all should move in Uz of the same ammount, is equivalent to saying that they won't be able to rotate about the Ry axis. It is a way to fix rotations in continuum models.

Additionally, if I want add another stage of analysis in continuation of the vertical and OOP analysis along the IP direction (i.e., keeping the vertical and OOP analysis locked in the current stage) what extra condition should I consider?

You just need another loadConst, so that the pressure loads controlled by the previous (OOP) displacement controlled analysis, remain constant. Then you can go on with another Displacement controlled analysis.

[kesavapraba]

Dear Sir/Madam
Thank you for your clarification. I understood the reasons, and things are clear now. I really appreciate your customer support in providing timely and concise replies.

[STKO Team]

Happy we could help, and glad to hear you are satisfied!