Design a rectangular beam section to resist a negative bending moment of $320$ kip $-$ ft $.$ Architectural

requirements will limit your beam dimensions to a width of $12$ in $.$ and a total depth of $20$ in $.$ Using those

maximum permissible dimensions, select reinforcement to provide the required moment strength. Please

note that you may need to add compression steel to make this a tension$-$controlled section. Use $f_c^{\text{'}}=5000$

and $f_y=60$ksi.