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# Civil Engineering/ETAB MODEL

Question
QUESTION: Babak,
Assalamu alaikum.We know there is a relation between dimension of  depth & width of column section which is depth/width=3.ie. if a column width is 10" ,maximum depth will be 30" .but if the depth more than 30" like 36" it would be designed as wall.So during model in ETAB it is to be modeled as wall and to be designed as shear wall.

Am I right or wrong.If there any alternative plz. help me.

Regards
BEH

[an error occurred while processing this directive]---------- FOLLOW-UP ----------

QUESTION: OK, Thanks. Suppose in a building there some column size r 10"X30" & some column size r 10"X36". So far I know as per ACI first types r to be designed as column because here depth-width ratio within 3 times that is(30"/10")=3.
But in 2nd types depth-width ratio greater than 3 times that is(36/10)=3.6
So it is to be designed as wall.
My question , is my concept right?
If it is right,what should be done during model in ETABs & how is it to be designed?

Thanks.
Shahjahan

Dear Shahjahan

This is a minor problem compared to the difference of walls and columns role in structure. The stability problem of columns can not be modeled with wall macro model. A Shear wall is designed to bear shear and moment usually without a combination with axial loads. You can see that the result of design in each mode is not the same. Then I propose you to design the column as a column and try to fulfill the aspect ratio of 3 . If you cant satisfy the aspect ratio, then I would  prefer to accept the error and design the member as a column.

Regards
BEH
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I am experienced in the area of earthquake engineering in electrical power industry, i.e. Lifeline Earthquake Engineering. My focus has been on structural seismic design of power installations. Recently I have got involved in project management in the category of constructional engineering.

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