Substructure- panel verification problem

[Anonymous]

Hello,

I have a 9 storey building model, ran calculation for full model- no errors, everything is fine. Now i want to calculate each storey elements separately, so i filtered one story's elements ( columns, walls, slabs) and saved as substructure.

Separate file shows correct diagrams and forces (as in full model), but i get one problem - in slab- required reinforcement calcutalions were fine, but when i try to run verification with stifness update (FEM) i get "Separate structure" and other errors about instabilities (type 2), and results are nonsense ( see attachements). 

What could be the problem?

[Artur.Kosakowski]

You can use the results saved with the substructure in the design modules but when you want to recalculate the model you need to support it. My assumption is that originally your story was supported on the lower one which is 'missing' in the model you currently want to calculate. Am I right?

If, yes define the supports under the wall consider the structure as a new one rather than the substructure. Run the static analysis first followed by the slab design and the stiffness update 're-calculations'.

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[Anonymous]

No, this is the lowest storey, with supports from main model.

Do i understand correctly, if i run static calculations on substructure, it will use only loads, defined in main model as load cases, but i will loose every effect from, like in my case, inclined columns (see attach.) In other words, do loads from 6th storey have effect on this -3 underground parking storey?

Is there a way to get these loads to substructure?

[Artur.Kosakowski]

The concept of the substructure is to use the results calculated for the whole model on a selected part either to access them faster or for running design modules. Such model is not intended as the equivalent of the whole model and if calculated only the load present in the substructure are included. You will need to convert forces from these columns to nodal forces (in their bottom nodes) in the substructure file. The similar macro can be found here:

http://forums.autodesk.com/t5/Autodesk-Robot-Structural/Local-reactions-API/td-p/3791474

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.