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Question
Hello eng.Hakimi


First,Sorry for the inconvenience and  my long questions  ( the first two question are more important than others ) :

1- do ( etabs or sap or safe) have option for moment redistribution) ? if they have it , please tell me where it is .

2-Is not it very difficult to redistribute the moments for a full tower - as example - and design manually after analyzing in Etabs ? ! Is not there certain conditions and considerations enable me to design in etabs without redistribution of moments ?

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3 - in "Ultimate Strength Design" we design for moment less than  Mu and Mp for all sections , that means there is no possibility for hinges to be formed thus we do not need to redistribute moment , isn't it right ?

4 - After analysis in Etabs ,  if we design without redistribution of moments , the results will be acceptable ?

Thank you very much
Best Regards

Answer
Dear Hassan

1- You Can do a push over analysis assuming nonlinear links at girders ends. It is not very hard to do exercise. You can perform it for entire structure automatically. I don't like a single file analysis because you may need to investigate in several views and have a sensitivity analysis.

2- After all you may know that redistribution of moment would provide you with a more efficient and economical design but you are not obligated to do .

3- The redistribution of moments is not a state which happens but it is a scenario to tune the margin of safety. The actual extreme load should me less than Mu , it doesn't mean that plastic behavior is not conceivable. But in any situation it is you as a designer that may decide about to have more advanced design or not.

4- You may guess that yes , may be it is more than acceptable to design without a moment redistribution, because this is your own art to choose your way to analysis and design provided that you don't pass the red boundaries of codes.


Regards
BEH

Civil Engineering

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Babak Esmailzadeh Hakimi

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

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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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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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