Model warnings

[Anonymous]

I have 3 warning after calculated a 3 storey RC frame:

-incoherent mesh on edges

-cohesion of the calculation model has been provided by definition of kinematic constraints in incoherent points of finite element mesh

-linear load as not been applied to a pannel

I have tryed to follow other post and change the mesh settings but it is even worse.

I have attached the model file:

http://www.filemail.com/t/36154234cbb54dc9834ae45ca2b1d2d6

thank you

[Rafal.Gaweda]

-cohesion of the calculation model has been provided by definition of kinematic constraints in incoherent points of finite element mesh

http://forums.autodesk.com/t5/Robot-Structural-Analysis/Structure-verification/m-p/3334787#M2792

-linear load as not been applied to a pannel

Check coordianates of your lines create for loads application or apply loads this way:

[Rafal.Gaweda · Accepted solution]

-incoherent mesh on edges

Model is inaccurate

See video how to correct mesh and geometry:

Meshed model attached

[Anonymous]

Thank you.

I don't understand what you have done with the walls using the spreadsheet. Is it something I will need in future for other models to avoid errors?

[Rafal.Gaweda]

I have corrected coordinates. Wall were not made in one plane

[Anonymous]

Thanks again.

I have removed few columns and run the calculation without re-mesh the slab. The max moment is 75.

Then I have meshed the slab following your instruction. The moment is decreased at 60 and I don't understand why. (the columns removed are at the opposite of the building, far from the max moment point).

Shall I trust in the new mesh with the lower value?

thank you

[t.sautierr]

have you same density of mesh?

is coarse, maybe the new one misses the peak ...

[Rafal.Gaweda]

FEM results strongly depend on meshing

[Anonymous]

Yes the mesh size is the same... 1 m

[Rafal.Gaweda]

???????????
I do not understand. File please.

[Anonymous]

http://www.filemail.com/d/lmrjcywrzmtyycu

I have attached both model. P3 is meshed by you.

Thank you

[Rafal.Gaweda]

This is what I see :

[Anonymous]

This is the map for Y moment at 1st floor.

[Rafal.Gaweda]

I wrote before: "FEM results strongly depend on meshing"

[Anonymous]

Thank you Rafal.

How can I connect a steel frame on top of the concrete slab?

[Rafal.Gaweda]

How can I connect a steel frame on top of the concrete slab?

?????????????

[Anonymous]

Hi Rafal,

Thanks for your advise so far. This building is proposed as a 3-storey RC, (+0m to +9m), with a 2-storey steel frame on top (+9m - +15.25m).

Looking at level 9.0, the steel frame columns over do not line up with the RC columns below. Therefore , my question is, is it possible to define pinned supports to the steel columns, on the RC floor at level +9.0m? Other posts suggest the use of rigid links, but I cannot understand this.

The other option is to create a separate steel model, and apply the reaction forces to RC model, but i would prefer just to have one model if this is feasible.

Many thanks, Franco

[Rafacascudo]

Use "rigid links" to link the concrete columm top node to the steel columm botton node. Then just use "bar releases" to pin the botton part of your steel columm

[Rafal.Gaweda]

Thanks for your advise so far. This building is proposed as a 3-storey RC, (+0m to +9m), with a 2-storey steel frame on top (+9m - +15.25m).

Looking at level 9.0, the steel frame columns over do not line up with the RC columns below. Therefore , my question is, is it possible to define pinned supports to the steel columns, on the RC floor at level +9.0m? Other posts suggest the use of rigid links, but I cannot understand this.

Possible solutions:

The other option is to create a separate steel model, and apply the reaction forces to RC model, but i would prefer just to have one model if this is feasible.

http://forums.autodesk.com/t5/Robot-Structural-Analysis/Only-reaction-for-new-model-API/m-p/3659280#...

[Anonymous]

Rafal,

Thanks for your reply. However, the steel columns do not line up with the concrete columns below. The slab at +9.0 is required to transfer the loads.

Can rigid links be applied to the actual floor slab?