Problem $3$

The below large, reinforced concrete, flat slab is $9\mathrm{.}5$ in thick with an effective depth $d=8in,$ and is supported by circular columns ${(}^{**})$ and has the following design attributes:

Dead Load $=$ self$-$weight $+40psf$

Live Load $=50$ psf

${}_{\text{c}\text{o}\text{n}\text{c}\text{r}\text{e}\text{t}\text{e}}=150$ pcf

Supporting columns are $13\mathrm{.}5$ in dia.

Assuming no moment transferred to columns, the ultimate punching shear stress caused by an internal column in psi is:

$($A$)63$

$($B$)126$

$($C$)202$

$($D$)136$

$(*)$ Dimensions shown are center to center for all columns.