How to model masonry wall between two cantilevered slabs (balconies)

[simon.hissette]

Hello,

I would like to model a masonry wall going on a hollow slab, but the rigidity of the wall modifies the behaviour of the slab and induces a negative torque in the slab and traction constrainsts in the wall (see the pic). But the masonry does not work with traction constrainsts.

Is it possible to get around this problem or to model it in a different way?

Thank you,

Simon.

@simon.hissette Artur Kosakowski edited the topic for better findability 

[Artur.Kosakowski]

Hi Simon,

Will modeling a wall as two parts with a gap in between work for you?

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[simon.hissette]

I tried to do it but there is another slab over the wall (see the pic), so the constrainsts go to the slab and the masonry is already in traction..

[Artur.Kosakowski]

What if you model these parts of the walls as a tension compression only bar elements instead? 

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[simon.hissette]

Could work for me.

How can i model it?

[Artur.Kosakowski · Accepted solution]

You assign it to selected bar(s). As they may be switched off (when under tension) you may consider removing them from the list of automatially generated self-weight and define it as point or linear load on a slab below instead.

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[simon.hissette]

I'll try this.

Thank you !

[simon.hissette]

When I start the calculation, Robot suggests me to use "DSC Algorithm" due to non-linear calculations.

Should I use it in this case?

Thank You,

Simon.

[Artur.Kosakowski]

Both (using DSC or not) will work.

[simon.hissette]

I receive the error message "Any convergence in the non-linear problem" (I did not use DSC algorithm).

Will it work if i use it?

[Artur.Kosakowski]

You may check but try these settings as well

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.

[simon.hissette]

Arleady the error "no convergence of nonlinear problem" with and without DSC algorithm..

Can't upload my file, too heavy.

Other parameters could solve this problem?

Thank you.

[Artur.Kosakowski]

Hi Simon,

It should be possible for you to attach the file when you save a model without results and then compress (zip) rtd file. Otherwise check:

https://forums.autodesk.com/t5/robot-structural-analysis-forum/sending-bigger-files/td-p/3795062

[simon.hissette]

Here is the link:

https://wetransfer.com/downloads/0c48f6c3b5496e99ca43dfe58e93c24320170428141022/a14870cd05e0f29ef84a...

See the pic to find the only compression bars.

Thank you !

[Artur.Kosakowski]

Hi Simon,

I don't think that the lack of convergence is due to compression only bars but definitely you should define supports at their bottom nodes. You need to find out what causes the instabilities of type 1. I have applied EP 30 thickness to all panels which seems to help a bit but  I'd suggest you to 'divide' your structure to smaller parts (e.g. where you have dilatation) and start e.g. with only bottom story first to see what actually happens and why. You may set these compression only bars as 'standard' to see deformation shape and check the displacements and rotations of nodes.

See the values for EP30 and no compression only bars (linear static)

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[simon.hissette]

Hi Artur,

"definitely you should define supports at their bottom nodes"
If the bottom nodes are connected to the slab, why should i define these supports?

What could be the cause of these instabilities?

Thank You,

Simon.

[Artur.Kosakowski]

Hi Simon

"definitely you should define supports at their bottom nodes"
If the bottom nodes are connected to the slab, why should i define these supports?

I'm sorry my mistake. I didn't switch display of meshes on and missed the slab due to its transparency. 

What could be the cause of these instabilities?

Something like this:

and

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