$6\mathrm{.}4.$ An $8$ in$.-$thick flat plate reinforced concrete floor system with $18$ in$.$ x $18$ in$.$ columns is planned on a $22$ ft x $22$ ft grid. The superimposed dead load is $15$ psf and the live load is $50$ psf$.$ Based on the shear strength of the system around a typical interior column, verify the adequacy of the design. Assume nomoment transfer between the slab and the column. Use f$!=4$ ksi, fy $=60$ ksi,and d $=6\mathrm{.}5$ in$.$