For the doubly$-$reinforced beam section shown below:

a$)$ Determine the nominal moment strength, $M_n.$ Use the iterative approach

suggested in your textbook. Verify whether or not the amount of tension

reinforcement complies with the ACI minimum reinforcement requirements. Also,

verify if the section is tension$-$controlled. Given $f_c^{\text{'}}=4800$ and $f_y=60000.$

b$)$ Determine the nominal moment strength, $M_n$ but assuming that there is no

compression reinforcement. There is no need to repeat the minimum

reinforcement check.

c$)$ Compute the increase in moment strength achieved by adding the compression

reinforcement, i$.$e$.,$ part a$)-$ part b$]\frac{?}{M_n(\text{p}\text{a}\text{r}\text{t}b)}$

d$)$ Compute the change in maximum tensile strain, i$.$e$.,$

$\frac{{}_t(\text{p}\text{a}\text{r}\text{t}a)-{}_t(\text{p}\text{a}\text{r}\text{t}b]}{{}_t}($ part $b)*100$

e$)$ Comment on the changes observed by adding the compression reinforcement

regarding moment capacity and ductility.