LQ$3.($CLO$2)(4$ Marks$)$ A simply supported, rectangular, reinforced concrete beam $300$ mm wide and having an effective depth of $500$ mm caries a total factored ultimate load of $70$ kN$/$m on a $9\mathrm{.}0-$ m clear span. The given load includes the dead load of the beam. Design the web reinforcement $($stirrups$).$ The steel grade $420$ MPa, and compressive strength of concrete $=21$ MPa. Use #$10$ U stirrups.