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Civil Engineering/RCC Column Design


While designing column we have to read the values of ρg = percentage of steel for Kn and Rn values from
the column interaction diagrams is there any approximate values to find the value of percentage of steel when of Kn and Rn values are known for different values f'c.
thankyou in advance

Dear Mohammad

I think for an approximate sizing you need to remove moments and replace it with an equivalent axial load. This type of approximation may be useful for estimation purposes and not as tip to find an accurate solution without effort. I have an idea. You can trace a line between ( max Pn, no moment) and ( no axial load, maximum moment) in a Cartesian system. This line is the magical line which will help you to have an approximate solution.


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Babak Esmailzadeh Hakimi


I can answer questions in Structural Engineering, Earthquake Engineering, Project Management and Project Control topics!


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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Bs degree in Civil Engineering from Ferdowsi University ,1988, Mashhad Iran, Ms degree in Earthquake Engineering, Sharif University of Technology, 1993, Tehran, Iran

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