ETABS Column Design

[BrandonHo]

Hi guys, I am wondering if anyone who uses ETABS frequently have this kind of problem I am having now with ETABS columns design.
The results below shows all 0 for a 200x1000 column although it is not 0 from analysis results?

And then I changed it to 250x1000, it gets a bit normal but I dont get why it requires so much reinforcement? I did hand check and it doesn't require that much at all.

The strangest thing is when I check the analysis results for that column under this load combination the moment do not match the design moments above.

Does anyone have this problem with ETABS as well?

 

[Agent666]

My only thought is at 200 wide and 4600mm long maybe you're failing some sort of slenderness check in whatever code you're working to? But best thing to do is contact your local CSI rep amd ask, because could be a genuine error.

 

[Retrograde]

Probably because at 200mm thick and 4500mm long the buckling load Nc is less than the axial load even with 4% reo (to the Australian code).

 

[Lomarandil]

And just to check -- is this a legitimate copy of Etabs? I've heard reports of CSI getting smart about making the ubiquitous cracked copies ineffective.

----
just call me Lo.

 

[milkshakelake]

Contact CSI. It could be that the internally calculated rebar is so high that something in the program is giving an error.

About high rebar, it might be because you have minor axis bending. I don't use ETABS for concrete column design; the results don't match my hand calcs. I use hand calcs 90% of the time or spColumn when slenderness is a concern, like 200mm columns.

 

[CompleteColumns]

Hi Brandon,

Can I ask what size reinforcement you've input in both cases and what standard you are using?

Complete Software

https://www.completecolumns.com/