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sway and non-sway moment magnifier and K factor 1

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mscme

Structural
Aug 18, 2008
2
US
I have been trying to model a 6 story reinforced concrete building and using ETABS to design the columns. I did determine that all the stories are sway and made the frame sway ordinary in the overwrites box. However it does not calculate the sway moment magnifiers, i did check the non sway moment magnifiers and they seem right.

I also checked to see if ETABS calculates the k-factor. I noticed that its default value is 1 (which would be conservative for a non-sway frame however ACI says the min is 1.2). I did a quick hand calc and noticed that the k-factors for my building should be between 2-4.

Is there a setting or option that has to be turned on for ETABS to calculate them?
 
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Read the ETABS documentation for column design - this is all explained in there (for instance see pages 2-7 and 3-12 of the "CFD-ACI-318-05.pdf" file). Sway moments are assumed to already be magnified (you must run a P-delta) and non-sway slenderness magnifiers are conservatively based on a K of 1 which can be overwritten by the user).

 
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