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Civil Engineering/effective length factor


I want to ask that what value of k (effective length factor) must be taken for a tapered section.. I have searched a lot but couldn't find any thing helpful.. The web tapers along the length of column and beam. and also is K value important in beams?  
For columns if base is pinned and other is free for sidesway.

ANSWER: Dear Nouman

The K factor is dependent of length, restraints of the ends of the column ( rotational stiffness of the member ends). For a column with simple supports in ends and without sway K=1.

For a column with simple support and free sway k tends to infinity.(instability)
For a column with fixed supports and no sway K=0.5
For a column with fixed base and allowed sway K= 1

For a complete study you would look up references.

Please feel free to ask further if needed.


---------- FOLLOW-UP ----------

QUESTION: Sir same will be in the case tapered sections?

Dear Nouman

For engineering purposes I suggest to use a mean value of I ( moment of inertia) for the column.

For the exact solution it is complicated. Take a look at the following link. For sure you would solve a complicated differential equation.

Please let me know wether you found your solution or not.


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Babak Esmailzadeh Hakimi


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


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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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