sog punching shear

huangyhg

sog punching shear
pouring,
i believe that the punching shear in a slab on grade could be analized in the same way we do in spread footings. instead of the column base plate or pedestal, i would use the footprint of the concentrated load.
normally, unless the slab is very thin or the concentrated load very heavy, punching shear does not control the design of the slab.   generally the design is controlled by the bending stresses.
aef
i would tend to agree with dlew's assertions.
punching shear check may be critical for a slab supporting high bay storage racking systems, or slabs with mezz columns......but the design approach for punching shear  is the same for any slab, be it on grade, suspended , or for a pad base.
i agree with everyone, but i would advise using the punching shear formula for plain (unreinforced) concrete, in section 22.5.4 of aci 318-95 (unless your slab has at least minimum reinforcement per code).
pouring (visitor)15 jul 02 12:37
thanks!!  i know how to apply it in that case!!
fyi - i usually have to analyze adding equipment in buildings which get placed on sog.  hence, the reason why i need to check punching shear (and one way shear when applicable).