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Differentiating gravity walls from shear walls in ETABS

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jahoel1400

Structural
Sep 10, 2018
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Hello all,

I am working on a two-story concrete structure with my firm for the first time. I have modeled all structural elements and applied auto quake loads. Note: the senior designer has hand calculated the entire structure, and I am verifying etabs results as we hope to switch to using ETABS/SAFE for all our concrete projects.

My question is: do walls that are not assigned pier labels contribute towards lateral stiffness?

I.e: I have a core that I am designing for 100% of the earthquake loads. There are other walls that for the purpose of this validation I do not want to include in seismic calcs. How do I ensure my perimeter walls are not acting as shearwalls?

I am considering perhaps that I need to assign Pierre labels to all walls in order to get the gravity design information, but as she releases in the respective directions for these walls that I don’t want to include.

Thanks!
 
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You could use shell area property modifiers to model walls which acts as a bearing walls with zero in-plane and out-of plane shear stiffness.
To release in-plane shear stiffness, use a very small value in shell area property modifiers f12.
Similarly, to release out-of-plane shear stiffness, use a very small value in shell area property modifiers M22.

Don't use an exectly zero value, because it could create numerical problems in your model.

My question is: do walls that are not assigned pier labels contribute towards lateral stiffness?
Pier labels are related to design of shear walls. Software reports average design results for piers with assigned labels. Pier labels has nothing to do with the stiffness of a wall.

I'll advise you to study in depth about the relevant features before using them.
 
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