column and slab moment when using rigid links VS no rigid links

[me1205377]

Greetings all,  please advise on the following observations 

 below are to identical simple floors. one with rigid link defining the column contour and one without.

i made a cut at column edge for both floors at exactly the same location. once with smoothing and once without; the moment difference is almost 100% for the first internal column 

also regarding the columns moment, the difference is more than 100%  

so please advice on which modeling way is better in reflecting the real behavior?

col size is 400mm x800 mm, mesh is 150 mm

model is attached

model is attached

[me1205377]

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[mustafahesenow]

Hi @me1205377

Could you attach the model please.

[me1205377]

the model is attached within the original post 

thank you very much for your interest 

[me1205377]

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[Artur.Kosakowski]

Hi @me1205377

Looking at three models (the 3rd one being with a beam instead the panel):

1. For a model model with rigid links the values of reactions are the same as for the equivalent beam model but when you reduce slab stiffness (Ig) then rigid links will 'overwrite' this reduction above the columns.

2. The values for smooting within the panel and no smoothing are very close but the prior reduces the peek over the columns.

Knowing the above the decision is now in your hands  

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.

[mustafahesenow · Accepted solution]

1

[Rafacascudo · Accepted solution]

We were talking about new features for Robot and"Rigid zone for slab columns " came to the discussion

"This should be build in order to not have problems with diaphragm "

"As you know you cant have slave nodes for 2 master nodes"

    Thinking about this issue of diaphragm "hidden" rigid links interfering with rigid links created to model Rigid zone for slab columns , I realized it can be done properly using what we have in Robot today .

  I tried on the model of this thread and it seems that it works very well.

  Instead of using Rigid links on the nodes inside the columm section area , I created a panel with the size of the columm cross section with the same concrete material but with huge E value( young modulus).
  This way it would not interfere with the rigid links due to diaphragm setting.

As you can see below , results are identical for the 2 models.

Rigid links like those can be easily created using the  Roman "Spider/diaphragmer" .
But probably our great API master can also create the "Huge E panels" with not so many trouble.

Comparison file attached

[me1205377]

thank you very much Mr. Rafeal 

i am very happy that this thread had a positive impact 😄