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Mode direction X and Y

13 REPLIES 13
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Message 1 of 14
A.wikipedia
750 Views, 13 Replies

Mode direction X and Y

Hi all.

I want find Mode direction X and Y.????

13 REPLIES 13
Message 2 of 14
Rafal.Gaweda
in reply to: A.wikipedia

Look at mode shape diagrams display.



Rafal Gaweda
Message 3 of 14
Jade_Cereno
in reply to: A.wikipedia

Hi,

 

My model seems to display a different mode shape than it should be

 

as my colleagues told me the mode shape is supposed to be this way:

 

mode 1 drift to x

mode 2 drift to y

mode 3 twising

 

I attach my model please take a look and help me on this

 

MIT-BsCE
Message 4 of 14
Romanich
in reply to: A.wikipedia

Can you upload the model? I can't see mesh on floor slabs.

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Roman Zhelezniak

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Message 5 of 14
Jade_Cereno
in reply to: Romanich

Unfortunately I cant Upload my File

 

😞 its 74 mb in size

 

regarding the mesh on floor slabs, i set it to rigid diaphram and it never meshed

 

please see photo

 

MIT-BsCE
Message 6 of 14
Jade_Cereno
in reply to: Jade_Cereno

by the way, the model i am using is the seismic model from robot

MIT-BsCE
Message 7 of 14
Rafal.Gaweda
in reply to: Jade_Cereno

Message 8 of 14
Romanich
in reply to: A.wikipedia

By default in this model for the floor slabs is assigned the calculation model Curtain Wall.

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Roman Zhelezniak

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Message 9 of 14
Romanich
in reply to: A.wikipedia

Create new one with the same options and select Stiffening diaphragm instead of Without stiffening.

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Roman Zhelezniak

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Message 10 of 14
Jade_Cereno
in reply to: Rafal.Gaweda

hi Rafal,

 

I cant seem to open the links on what you posted. maybe our it prohibited it.

 

anyway, can i send it on your email instead?? if its possible

 

about curtain wall setting on the floor slab, I already changed it to rigid diaphram with FEM meshing.

 

still it not genereting the mode that is desirable

 

See attached three modes

 

My Colleaugues told me that member stiffening maybe the cause of mode 1 to be twisting, but I doubt that because my model is prismatic and corewalls are placed on the same place as the other, much like a mirror image.

 

Can you please help me on how to do this right?

 

From My understanding, this is the forst step to do before going to an in depth seismic analysis as I need the natural period of the building

 

 

 

 

MIT-BsCE
Message 11 of 14
Romanich
in reply to: A.wikipedia

If you have torsion in the first mode, you should to change a floor layout. For example to add walls on the perimeter.

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Roman Zhelezniak

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Message 12 of 14
Jade_Cereno
in reply to: Romanich

Done that Sir and It helped. ^_^ Thanks!Cat Happy

MIT-BsCE
Message 13 of 14

Of course you will have torsion in the first mode (which is bad) beacause you have two cores in the middle of the structure floor so close to each other.

As mr. Romanich said, adding shear walls to perimeter of the structure should solve the problem.

I am attaching two images, maybe they can help.

 

Also, take a look at this link.

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Mirko Jurcevic


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Message 14 of 14

Thanks! this is a great help!Smiley Happy

MIT-BsCE
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