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Can any one please explain the instability in that model.
http://www.mediafire.com/file/1gjrjjj6ee0tvod/Hotel.rtd
I had checked your model and have some comments on it :
1-For walls support its not correct to define pinned support because along the wall you wont have rotations only out of plane direction anyway this is concrete structure and I think its correct to be fixed support not pinned (you cant achieve pinned support in concrete columns or wall at the base you may have partial release not full ) .
2- Defined releases on the beams When you define pinned release its not correct to release it about local x direction (release for torsion ) this means its allowed for the beam to rotate about its own axis which is logically wrong So you should un check the x direction form the release type for both ends .
3-You have incoherent mesh on edges need to be corrected and you need to switch off the kinematic constrains from job preferences.
4-after all of this do the calculation then if the insatiability warning appear again jut choose the reported nodes and go tables then nodal displacement
For sure you will that there displacement very small which is mean to stability to be ignored .
5- For more information and tricks refer to the webinar https://www.youtube.com/watch?v=5CCLzG12JQ4&t=1216s
Mr. @mustafahesenow
Thank you for your time. I have some questions on your comment:
1- I think the connection between the wall and it's foundation is more to be pinned not fixed. fixation means that the steel connection between them more than the development length besides to that the Inertia of the two elements are convergent.
and another something, when i start drawing walls it is drawn in the program with a default linear hinge at it's base.
2- You are right at this point, but when i un-check the Rx release that means that at the beam end it will be a torsion moment at the point that it's lies on another beam. Is that right?
3- I tried to make meshing more than 10 times with different ways, and every time there's incoherent mesh warning. If you please know the rightest way to make meshes for that model please share it.
And i always switch off the use of the kinematic constraints but, i switch on the option of: obtain incoherent mesh > Kinematic constraints in incoherent points. is that right?
4- at that point you said that it will give me an instability warning although i have checked and corrected the warnings.
why is that?? that means that RSA gives incorrect warnings !
Finally thank you very much for your time and attention Mr. @mustafahesenow 
1- I think the connection between the wall and it's foundation is more to be pinned not fixed. fixation means that the steel connection between them more than the development length besides to that the Inertia of the two elements are convergent.
and another something, when i start drawing walls it is drawn in the program with a default linear hinge at it's base.
As I mentioned to you out of plane of the wall you are correct but in plane of the walls it wont rotate because you have a wall will huge height for the default option id doesn't mean anything.
2- You are right at this point, but when i un-check the Rx release that means that at the beam end it will be a torsion moment at the point that it's lies on another beam. Is that right?
You can reduce Ix along the beam by reduction of moment of inertia of the beam but by release is not logic and wont solve the torsion issue in the beam.
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3- I tried to make meshing more than 10 times with different ways, and every time there's incoherent mesh warning. If you please know the rightest way to make meshes for that model please share it.
And i always switch off the use of the kinematic constraints but, i switch on the option of: obtain incoherent mesh > Kinematic constraints in incoherent points. is that right?
the incoherent mesh warning is very useful warning it shows you that you have problem with your building accuracy need to be fixed
see attached picture for incoherent mesh fixing of your model :
If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.
And i always switch off the use of the kinematic constraints but, i switch on the option of: obtain incoherent mesh > Kinematic constraints in incoherent points. is that right?
Please take a look at help http://help.autodesk.com/view/RSAPRO/2018/ENU/?guid=GUID-787B583F-32DB-4F29-847A-DC7D803BEDB7
the detailed result for such panels will not be correct this option is just to give priority to finish the analysis (if the engineer assumes that these incoherence wont affect the result )
4- at that point you said that it will give me an instability warning although i have checked and corrected the warnings.
why is that?? that means that RSA gives incorrect warnings !
sometimes it happened anyway its type 3 I really recommend you to watch this webinar
https://www.youtube.com/watch?v=5CCLzG12JQ4&t=1216s
If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.
4- at that point you said that it will give me an instability warning although i have checked and corrected the warnings.
why is that?? that means that RSA gives incorrect warnings !
The instability of type 3 is also reported for large difference in the stiffness of the elements of the model which may be triggered by use of the elastic releases on all edges of the panel as surface elements have no in-plane stiffness (small value is assumed). I corrected the geometry and meshing in your model to get rid of very short elements to determine what is the exact cause of the reported instability first, and then added dummy RZ supports in an arbitrary selected nodes of such panels. There is no instability reported for such modified one.
If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.
Artur Kosakowski
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