shear along support beam caused by concentrated load

huangyhg

shear along support beam caused by concentrated load
i'm analyzing a continuous slab, with a typical panel 6'8" x 20'.  the panel is supported on all four sides with steel beams and girders.  i'm basically treating the slab as a one-way slab.  i'm using a fem program to determine vu and mu.  large point loads are located very near the steel supports.  because of this, my results show very high vu (in k/ft) that exceed (phi)*vn in localized areas along the support beam where the point loads are located, while the remainder of the slab located along the support beam is well below (phi)*vn.  does this mean that the slab should be considered inadequate for shear in these localized areas?  it seems logical that more of the slab would act to resist this high localized shear, but how do i know how much? how should i approach this?  in other words, it appears the slab is failing in beam shear at these locations, but is it really?
if you have high point loads on the slab near the supports then you need to look at punching shear for these e.g. treat them as upside down columns.
carl bauer
carl nailed it on the head.  if vu is greater than phivc, then try increasing your slab thickness at concentrated loads with a drop panel or something similar.