SAP2000 shell stresses

[dmdblkeng]

I'm doing a pile cap design using sap2000. Can someone help me interpret the result please? I'm getting V12=V23 = 13.6 kips/inch and Vmax = 22.08 kips/inch. Is this the shear force per inch of the pile cap thickness? or per inch of the width? I want to check for punching. My pile cap is 12ft x 12ft x 36-inch deep. Thanks in advance.

 

[UcfSE]

http://docs.csiamerica.com/help-fil...nternal_Forces_Stresses_Output_Convention.htm

 

[dmdblkeng]

hi UcfSE, I think my question is not clear..sorry for that. my problem is interpreting the result. if I have that V12 & V13 forces in kips/in, should I compare that to 2*sqrt(fc')*pile cap depth?

 

[JoshPlumSE]

Plate forces in general are using given on a per length width basis. Shear per foot or plate width, moment per foot of width et cetera.

That way, you can compare the plate force for adjacent plates of different sizes. Make sense?

 

[dmdblkeng]

So to which value I should compare the V12 or V13 then? I just want to know how to check the beam shear and punching shear in my pile cap.

 

[JoshPlumSE]

Those are FEM force results representing the shear force in the element. How to go from FEM shears to a punching shear code check is a good question. I'm not sure there is a definitive answer on how this should be done.

Personally, I usually go back to more traditional hand calcs. Look at the moment and shears in the column or pile support. Look at the geometry of the pile and punching perimeter. After that, it's just a hand calculation.

However, the SAFE guys (if I remember correctly) try to use direct FEM results in their punching calculations. So, you might check their help files and documentation to see if that makes sense to you. So, there are other ways to do it.

I use the hand calc method because it's easily spelled out in ACI code references. Though I'm not suggesting that this method is better than the other, just that is has easier, more defensible support in the ACI code documents.

 

[dmdblkeng]

Hi JoshPlum, yes of course it's easy to do it manually but I'm just curious how to interpret these results that I'm getting otherwise these are useless. At this moment I really don't have a clue what these numbers mean.

Thanks...