ROBOT STRUCTURAL SMALL DISPLACEMENTS/DEFORMED SHAPE

[tovarog23]

Hello! 

I have been working on a steel structure model that I have already tested at other different structural analysis software (MIDAS Gen, ETABS) and for some reason, in the new 2022 RSA, when I run the model, the displacement values and deformed shape are almost non existent and way too small. I have a large cantilever that carries two levels, and, despite the fact that I was expecting to get a large value of deformation, the value turned out to be less than 1cm, without even using bracing and using very small steel sections. I have attached an image of the deformed shape which makes no sense. I have already checked everything and cannot find any error. I do get an instability of type 3 whenever I run the model, but not sure if that is somehow related. 

 

[Stephane.kapetanovic]

hi @tovarog23 

Could you tell us your model ?

Best regards

[tovarog23]

The model is just consists of steel framing and cladding. Only secondary beams have pin-pin releases and all columns have a pinned support. In terms of loads, it has gravitational (Dead, Live) and a response spectrum analysis with 10% eccentricity for each direction. I would love to share the model in this platform, but not sure how to do it as files bigger than 71 MB are not allowed. 

[Stephane.kapetanovic]

You can send download hyperlink.

[Krzysztof_Wasik]

HI @tovarog23 

Save file as RTD without results than zip it. Then it should be small enough to attach it to forum post.

[tovarog23]

Thanks for the advice, I have attached the model that I made. 

[Krzysztof_Wasik · Accepted solution]

Hi 

You have used full stiffening (rigid body)  model for slab panels simulation. Change it to Partial stiffening (in XY).

[tovarog23]

Thanks a lot! I initially thought that full stiffening would provide me a rigid diaphragm behavior, and that the partial diaphragm would be more of a flexible option. If I wanted RSA to consider a flexible diaphragm, what should I use?

[Krzysztof_Wasik · Accepted solution]

Hi @tovarog23 

In this case you should use Partial stiffening (in XY)..