Question regarding shell modelling continuity

Question regarding shell modelling continuity

Ataíde
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Message 1 of 5

Question regarding shell modelling continuity

Ataíde
Contributor
Contributor

Hello!

I'm trying to make a concrete slab, and faced this modelling situation:

  • Modelling the slab as one, or splitting it between beams gives different results for the reinforcement maps.

I noticed this in the model I was working, and the difference was quite huge, as shown in image (the tags decided to disappear, I don't know why they do it sometimes. But on the upper side the deflection is 2.4cm, on the lower side it is 3.4cm):

Atade_0-1760697771117.png

 

So I made a simpler model to analyse it, which I share annexed (the jump isn't as noticeable, but it's there).
On top, slab modeled as one, on bottom, slab split in the beam.

Deflection u

Atade_1-1760697931611.png

 

Area reinforcement X-:

Atade_2-1760698092382.png


Mesh and axis considered:

Atade_3-1760698133332.png

 

I'm new to shell modelling and need to study this further, but would like to know beforehand if this is expected, and if I'm missing something. It only happens in the reinforcement maps, regular maps everything is smooth.

 

Thanks in advance!

 

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Message 2 of 5

Romanich
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Hi @Ataíde ,

 

Romanich_0-1761002613396.png

 

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Roman Zhelezniak, P.Eng.

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Message 3 of 5

Ataíde
Contributor
Contributor

Hello @Romanich,

 

Thank you for your reply. The solution doesn't seem to solve the issue:

Atade_0-1761037487485.png

 

Is it a wrong modelling procedure to make the slabs separate at the beams?

 

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Message 4 of 5

Romanich
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Hi @Ataíde 

 

Romanich_0-1761055274977.png

 

Do you find the posts helpful? "LIKE" these posts!
Have your question been answered successfully? Click 'ACCEPT SOLUTION' button.

Roman Zhelezniak, P.Eng.

Robot Evangelist & Passionate Civil Structural Engineer

LinkedIn | Robot & Хобот | App Store for Robot
EESignature


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Message 5 of 5

Ataíde
Contributor
Contributor

Hello @Romanich ,

 

Thank you very much for your reply.

So if I understand correctly, when working with a slab that's modelled as separated shells, in order to use the reinforcement calculation from Robot, it is needed:

  • For the reinforcement areas, the "globally average design forces"
  • For deflection, verification -> with FEM method

Without these premisses the results aren't accurate.

 

Is this correct? 

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