www.sefindia.org

[Anant_Nair]

I have been modelling a structure in Etabs 18 and the column Ast i recieved from it was quite high.So out of curiosity i repeated the same using Etabs 2016 and cross checked the support reactions and member forces and moments just to be sure it was similar.The two models showed almost same values.
However on giving the design command in the new Etabs16 model I obtained significantly lesser Ast values for all my columns (almost equal to min. Ast ). I checked the column moments and axial forces just to be sure and the calculations seem to be correct.

The thing i noticed in my Etabs 18 model is that in the design summary page, the Mu2 value used in design was not only very high, i couldnt find that particular Mu2 value by checking the member moments of the column.
For example, by checking the member force of a particular column I obtained an Mu2 value of 83kNm and Mu3 value of 164kNm, but the design summary page shows that the section has been designed for an Mu2 value of 220kNm (which i cannot seem to find anywhere) and Mu3 164kNm (same as in member forces option as said above).

The etabs 16 model has however designed the column for the correct Mu2 and Mu3 values.
Please help me out.


(Building is a G+3 structure has been designed for dead,imposed,earthquake and wind load)

[faisal hafiz]

[Anant_Nair]

Thankyou for  the reply, switching off the capacity ration indeed does give the result as expected. i was also able to get the same result by changing the framing type from Ductile to Ordinary in the overwrites of individual members.

My question though is, whether it is technically correct to adopt the obtained lower reinforcement during design.