Is it my fault in modeling? am i missing sth?

[PujanG]

I modeled a multistory bulding and applied various load combination to which the behaviour of structure seemed to be satisfactory.

However, under the 'Envelop combination' of all combination the top floor showed some unusual behaviour (look at the attachment).
I've assigned diaphragm constraints to all floor levels, anything else i am missing?

Second, the column attached to the shear wall is supposed to be acted upon by highest axial force. here it doesn't look so. (look attachment)
What am i missing?

Any help or hint would be much appreciated.
Thank you.

 

[stressed]

Looks like you might have a connectivity problem. Those frames at the top look unsupported. Also, your wall mesh looks unusual. Why did you mesh the walls in one direction about 2/3 up the height? Why not make a more uniform mesh - 4x4 or something like that?

 

[PujanG]

Thank you Stressed for your valuable response.

I had assigned the top frame with diaphragm constrain with Auto Axis, which seems valid for the inclined slab. However, its response turned out to be something unexpected, which you referred to as 'connectivity problem'.
I changed the axis of diaphragm to Z axis. It solved the problem.

I haven't yet figured out the problem related to be lower axial force on column attached to shear wall. And, as far the meshing is considered, you'd be surprised to know, I didn't Mesh it at all!!
Is it mandatory to mesh area elements???

The mesh you are talking about , at the 2/3 of height, isn't a mesh. its just another area element connected to the coupling beam above the entry of lift door. ( I used two area elements instead of 1 just to make it easier to model the opening for lift.)

I revised the model, used single area element & meshed it as u said, but again it didn't turn out in my favour.

Anyways, thank you stressed.

Regards,
Pujan