For the T$-$section shown below, determine the design moment strength, $M_n,$ for

the two design situations indicated below. The beam has a $20$ ft span and is cast

integrally with a floor slab that is $3\mathrm{.}5"$ thick. The clear distance between webs of

adjacent beams is ${45}^{\text{'}\text{'}}.$ Start by determining the effective slab width to be used as a

beam flange. In each case, verify whether or not the amount of tension

reinforcement complies with the ACI minimum reinforcement requirements. Also,

verify if the section is tension$-$controlled. Check the section for minimum width

requirements.

Given $f^{\text{'}}{c}_c=3000$ and $f_y=60000.$

a$)$ Use $A_s=8$#$9$

b$)$ Use $A_s=8$#$10$

c$)$ Comment on the difference between these two design cases.