SAFE-PUNCHING SHEAR

[Hamid2019]

Hi Guys,
I have a problem with safe punching shear in column location when I have both column above and bellow.
In this point the model shows 1.80 ratio for punching shear but when I remove the above column it goes to 1.10.
would you please help me if you know the reason and solution.

Thanks,

 

[JoshPlumSE]

Obvious questions:
1) Are the columns truly aligned? Or, could there be a slight offset?
2) Same size columns above and below?
3) Does the column above only have axial load? Or, does it also have moment / rotation that could be affecting the column / slab below?

 

[Hamid2019]

Josh, both columns have the same size and truly aligned. and column above doesn't have any moment.

 

[JoshPlumSE]

Interesting.... Is this a large model, or have you stripped it down / simplified it at all?

If it's a reasonably small model, you could post both versions of your EDB file. I would certainly look at it. Though I have to admit, that I'm still learning ETABS. Therefore, I cannot promise anything....

 

[Celt83]

without knowing much about the column layout, the presence of a column up and down would be stiffer than the condition of just the column down so the latter would likely result in a larger unbalanced moment at the joint.

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering