Etabs column out put reinforcement

[Engr Fayaz Ahmad]

AOA.

 i am designing a 7 storey hospital building but after running design in etabs v16, some of the column on ground floor or first shows very high reinforcement  as compared to upper or lower stories columns. the grid size  and loading is same for all stories.  can some on kindly point out what could the reason?

Thanks 

[Ayesha]

Generally the reinforcement in bottom columns is expected to be more excluding some assumptions. Why is this strange to you? What are you thinking that has gone wrong that made you suspicious of the results?

[Engr Fayaz Ahmad]

you are  right about the reinforcement will be higher at lower stories but my query is why is the reinforcement at intermediate column being high than lower story and upper story.

thanks

[Ayesha]

From your attached image, its only higher in one intermediate column.

That can be due to a number of reasons like:

1) Your column geometric properties are not assigned correctly.

2) Gravity and lateral Loads are applied incorrectly.

3) The framing is such that there is more load on that column.

4) The attached image is a 2-D image. Maybe there is no beam at intermediate level resulting is larger unbraced length.

This can be due to a number of reasons as your question is open ended and there is no definite pattern in results. Check you assignment and "do manual calculations" and compare with ETABS results. Without that, you won't know. So do your manual checks of column design and get back with your result comparison.

 

[abbaskhan2294]

  On 3/9/2019 at 12:09 PM, Engr Fayaz Ahmad said:

AOA.

 i am designing a 7 storey hospital building but after running design in etabs v16, some of the column on ground floor or first shows very high reinforcement  as compared to upper or lower stories columns. the grid size  and loading is same for all stories.  can some on kindly point out what could the reason?

Thanks 

Expand  

I suspect there may be a concrete wall element at the bottom most story increasing the stiffness and decreasing the demand on the columns or u may have used reduced geometrical properties in the intermediate story as compared to the lowest story. 

Also there can be another possibility about the base shear level defined for the seismic loads.

Edited August 15, 2019 by abbaskhan2294