$5\mathrm{.}6$ A rectangular beam section is $b=16$ in$.$ wide and has a structural effective depth of $d=26\mathrm{.}5$ in$.$ Flexural

reinforcement consists of three No$.9$ bottom bars and two #$9$ top bars. The beam is simply supported $($subjected to

positive moment so the top of the beam is in compression and the bottom of the beam is in tension$).$ Given that the

factored shear $\text{'}Vu\text{'}$ on the section is $90$kips, and a specified concrete strength of $4000,$ determine the required

spacing of No$.4$ stirrups. Reinforcing bars are all fy$=60,000$psi.

$->$ Please be specific on how to find Vc values since that is what I am most confused about