one way solid slab

[Anonymous]

Hello

I tried many approaches to design the attached file as a one way ( X is the main direction) solid slab ( slab on beams), but didn't find the best one

1-first I modeled the slab as a shell with beams ( with offset) I end up by having Myy much bigger then Mxx and a very big deflection 17cm

2- I modeled the slab as a shell but with reduction of moment of inertia ( to let beams take the most of the moment) I end up bye having non-logic results for moments ( also Myy>Mxx) but with reasonable value of deflection 

3- I modeled the slab as a shell with material orthotropy with n2=0.001, I end up by having desired results of moments ( Mxx is the main moment) but with big deflection 14cm

I don't know which approach is correct, I will be attaching file here if anybody can help me

Thank you

[Mohammed_Ata]

It is so clear in this tutorial 

[Anonymous]

@Mohammed_Ata can you please re-post the video, I can't find it.

Thank you

[Rafacascudo]

@Anonymous your model was not attached , so we cannot be sure what are your Mxx and Myy without knowing what you are setting as your local direction to show the results. but...

1- 1st of all if you also want to have results for the slab , then you cannot use the simplified method  for distribution of the loads. Results from "Maps..." will show up but they will be completely wrong as the applied loads didn´t "pass" through the mesh nodes to go to its edges where they can find support. Imagining that you model has 4 beams and 4 pinned supports on the 4 corners , your applied loads will go directly to the longer beams. So Using the simplified method is only good for beam results and only  accurate if the load is  uniformly distributed and applied on the whole area of your slab/panel as the distribution is done using tributary areas. Simplified distribution can be very wrong for concentrated or contour loads!

2-For me , the best option to have results very similiar(as calculated by hand) to what you would have for an "ideal" one way slab would be using the material orthotropy as you already did.

Can you send the model ?

Geometry and slab thickness can have a great impact on the results

[Anonymous]

@Rafacascudo thank you for your help, but as I said before when I used the " material orthotropy" method, I end up by having non logic value of slab deflection. 

Anyway I attached the file below for you to check it 

[Rafacascudo]

not attached again. what is the file size?

[Anonymous]

@Rafacascudo it's 7.77 MB. I'm trying to re-attached here

[Anonymous]

@Rafacascudo I tried to zip it

[Rafacascudo]

@Anonymous

Your vertical displacements are way too high probably because you set the wrong slab orthotropy direction .

Using the correct direction , global X , deflections are in fact smaller when comparing to the  homogeneous slab type.

Moment Mxx will be almost the same and Myy will be close to zero on the ortho slab.

Comparison model attached