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Dear All, I happened to encounter an issue while designing Slender column for which I would like you all to put your feedback on. In, ETABS slender columns are designed with one of the method, moment magnification. (ACI 318-11 10.10.5). This method often result in high magnified moments because of the lower flexure stiffness EI computed from =0.4EI/(1+Bdns) (ACI 318-11 Eq 10-15). This problem is also address in one of the paper from Sturcutre Magazine. http://www.structuremag.org/?p=1005 Has anybody have experience to utilize other method Elastic Second Order Analysis (ACI 318-11 10.10.4) or Non-Linear Second-Order Analysis (ACI 318-11 10.10.3) for design of Slender Column?. Especially with reference to ETABS. I appreciate sharing your kind knowledge and experience. Thanks

etab design a beam on many locations if you check for max reinforcement for top then you will find your correct value of moment at support and if you select for max bottom reinforcement you will find middle span value for moment at middle.the attached screen shot is for -ve moment at support for +ve you should select max bottom reinforcement location. see the attached pdfmoment.pdf

If I understood your question correctly, then NO you have to also think about structural integrity. Follow the standard rules given in ACI detailing manual or in BS standards. See how the bars are developed in PCA notes.