The admissible deflection exceeded

[REDO10]

Hi,

the required reinforcement of the slab below does not pass due of excessive deflection and large opening !.. I changed the thickness of the slab several times but it still does not pass! so how to solve this problem and what can you Suggest me to do?

My file is attached bellow

thx

[REDO10]

Hi,

the required reinforcement of the slab below does not pass due of excessive deflection and large opening !.. I changed the thickness of the slab several times but it still does not pass! so how to solve this problem and what can you Suggest me to do?

my file is attached bellow

Thx.

[Rafal.Gaweda]

Turn this off :

[REDO10]

Hi Rafal,

Thx for your response

I verified what you told me and that's ok! the deflection has decreased and the calculation of reinforcement pass! .. but reinforcement seems so low especially along the opening, see the capture below (length of opening is 8.30m ) ..what you think?
Should I add a beam along the opening for stiffen it?

[Rafal.Gaweda]

ON stage of Provided Reinforcement you can get this:

[REDO10]

Hi Rafal,

Thx for your reply

I calculated reinforcement on X and y axis, but can't get Punching calculation, so how to do that?

Thx.

[Artur.Kosakowski]

See: http://forums.autodesk.com/t5/Robot-Structural-Analysis/Punching-Results/m-p/3099554

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.

[t.sautierr]

Rafal, why turning this box off, decreases the deflection? 

[Rafal.Gaweda]

@Note: If Globally averaged design forces is selected, you should be careful while calculating reinforcement for plate structures consisting of panels that are not located in one plane, for global averaging may result in the situation where quantities that do not correspond to each other are averaged for the edges of such panels.@

http://help.autodesk.com/view/RSAPRO/2015/ENU/?guid=GUID-F1F2DAC9-CB75-4EF3-9E36-16365BAC9E41

[t.sautierr]

Oki and then the calculated deflection taking into account reinforcement can be false .... understood.

I assume same happens if 2 pannels are in the same plane but one is released on the edge and the other is fixed ?

Thx

[Rafal.Gaweda]

Can be but with smaller side effect because XX force is not averaged with XX force coming from different direction

[REDO10]

you mean if there are beams not necessary to verify punching?

[Rafal.Gaweda]

Not necessery

[jclcereno]

---

@REDO10 wrote:
you mean if there are beams not necessary to verify punching?

---

I think what Rafal is trying to say is that, your Slab is not really a Flat Slab. Flat Slabs which has Column Supports only are the ones checked for Punching Shear.

Slabs with beams are mostly checked for moment, shear and deflection. Then the beam supporting it are checked for moment, shear and deflection also.

Your slab can be analyzed as a beam. From what I know, beam elements are not checked for punching shear.

[t.sautierr]

Rafal, I tried to test the reinforcement of two span slab, one span is fixed on central support, the other is hinged.

I would expect differences in top reinforcement if I ticked average of dimensionning efforts or not but strictly no difference, why that?

Ithink it averaged is a different way but I don't understand how, is it averaged along the support and not from each side?

[Rafal.Gaweda]

1. You should not do this in such case
2. You are right - not averaged due to linear release - but see my answer (1) above .

[t.sautierr]

1) Then is useful to tick this option only in case of point load for example?

2) I read your commentary (1) but actually I don't understand ... sorry, how is it averaged?

[t.sautierr]

Or Maybe it is only because of the release taht Robot recognised it and don't make the average ? if not release, and different values on the right and left side for other reason, it would have been averaged?

[Rafal.Gaweda]

1) Then is useful to tick this option only in case of point load for example?

support, columns also

2) I read your commentary (1) but actually I don't understand ... sorry, how is it averaged?

in short :   ((nodal_value_of_FE_meeting_in_node) + (nodal_value_of_second_FE_meeting_in_node) ) / 2

in case of meeting more FEs in node ()1+()2+()3..+()n / n

[t.sautierr]

Understood, in my example : 4 FE, so averaged in 4 direction for MYY, MXX etc .....

In case of linear support what happens actually?