$24\mathrm{.}2$ The rectangular slab shown in Fig. P$24\mathrm{.}2$ is a typical interior panel of a large floor system having beams on all column lines. Columns and beams are sufficiently stiff that the slab can be considered fully restrained along all sides. A live load of $100psf$ and a superimposed dead load of $30psf$ must be carried in addition to the slab self weight. Determine the required slab thickness, and specify all reinforcing bars and spacings. Cutoff points for negative bars should be specified; all positive steel may be carried into the supporting beams. Take support moments to be $2$ times the span moments in the strips.