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estimate soncrete coloumn size for ETABS?

estimate soncrete coloumn size for ETABS?

estimate soncrete coloumn size for ETABS?

(OP)
Hi
Is there any experiment for estimate initial section size of column for modeling concrete structure in ETABS?

RE: estimate soncrete coloumn size for ETABS?

Hi,

im not too familiar with the ACI code. i used to calculate with the din code (Germany). In this code you use a stress for Concrete considering let say 1.2% of reinforcement and a 2.1 safety factor. Then you divide the total load per column by this stress and you get the requiered area of concrete. I hope that this could be usefull.

LG

RE: estimate soncrete coloumn size for ETABS?

You have to guess a section to start with, actually you did it before performing the analysis, right; well to that section assign between 1 and 4% of rebar, choose a distribution for it,, and voila. After that you have to rerun the design software to see if the columns pass and the safety factor on them.

Regards

RE: estimate soncrete coloumn size for ETABS?

This was a rule of thumb I picked up in school for the ACI code.  1.6P/0.5f'c = Ag of the column. Just take the axial load of the column and divide by half the concrete stress to get an estimate.

RE: estimate soncrete coloumn size for ETABS?

(OP)
thank you...but I want to know how can I estimate column size before input the model in ETABS?

RE: estimate soncrete coloumn size for ETABS?

nimaoy,

With all due respect, the answer ash060 gave you is appropriate.  So you just need to be able to estimate your column loads to get a start.  If you don't know how to do that, you should not be using a complex program like ETABS.

RE: estimate soncrete coloumn size for ETABS?

(OP)
as you know we should first of all estimate column size and after that we can analysis and calculate force and moment, so my question is : first of all and before analysis how we can estimate column size for modeling and analysis in ETABS- for example 30*30 or 40*40 or....?

RE: estimate soncrete coloumn size for ETABS?

hi nimaoy

You should follow the ash060 suggestion. You have to calculate the Ag(total area).So if you want a square column the side B will be = (Ag)1/2.
  

LG

RE: estimate soncrete coloumn size for ETABS?

(OP)
so, how can I guess P (axial force) before analysis ?

RE: estimate soncrete coloumn size for ETABS?

Ummm...a column load take down by hand calcs based on tributary areas?  If you can't estimate a column load by hand then you shouldn't be analyzing the column in a program.

RE: estimate soncrete coloumn size for ETABS?

You calc the tributary areas per the dead load and live load for gravity columns, and if you have seismic you could take a lower value of stress or lets say1.6P/ 0.35f´c in ACI code for lateral resistant columns to take into account the seismic forces. This is like a fist approach. So when you create your model, you will have elements with more certain rigidities.
 

LG

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