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Hollow core slabs and seismic

7 REPLIES 7
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Message 1 of 8
Ivana1607
711 Views, 7 Replies

Hollow core slabs and seismic

Hi,

can anyone tell me is it possible to do modal analysis and seismic calculation with hollow slabs in construction model?

Thank you very much.

Ivana

7 REPLIES 7
Message 2 of 8
Rafal.Gaweda
in reply to: Ivana1607

Yes, it can be calculated.

 

hs.jpg

 

 



Rafal Gaweda
Message 3 of 8
Ivana1607
in reply to: Ivana1607

Thank you for your answer. I've already defined hollow slab in my model but during analysis error 902 appears. After that I changed the slab into homogeneous (just for check) and no errors showed, calculation was fine. I thought maybe self weight of hollow slab is not converted to masses?!

Message 4 of 8
Rafal.Gaweda
in reply to: Ivana1607

Error description : 

 

http://docs.autodesk.com/RSA/2013/ENU/index.html?url=filesROBOT/GUID-8E8ED7A4-9A55-4F1F-8771-7E1A9CE...

 

902

Negative eigenvalue has been obtained

 

PLease send me model to check



Rafal Gaweda
Message 5 of 8
Ivana1607
in reply to: Rafal.Gaweda

Here is the model. (Original model is too big to send so I made a little example)

Thank you.

Ivana

Message 6 of 8
Rafal.Gaweda
in reply to: Ivana1607

Ivana,

 

Take a look below. You have defined wrong geometrical properoes of holes in holow slab.

Opening bottom edge is 2mm below slab bottom layer

ho/2 = 160 and hc=158 -> ho must be less or eq to 316

 

ho.jpg

 



Rafal Gaweda
Message 7 of 8
Rafal.Gaweda
in reply to: Rafal.Gaweda

To help you checking : matrix values can not be negative 

 

matrix.jpg



Rafal Gaweda
Message 8 of 8
Ivana1607
in reply to: Rafal.Gaweda

Yes, that was the problem. Thank you very much!!

Ivana

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