$f_c^{\text{'}}=3000$

$f_y=60$ksi

NWC$.$ Min. Cover $={1\mathrm{.}5}^{\text{'}\text{'}}{M}_n=?$

$(2)$

$f_c^{\text{'}}=4000$

Grade $60$ steel NWC$.$ Min. Cover $={1\mathrm{.}5}^{\text{'}\text{'}}{M}_n=?$

spiral member.

$(3)$

$f_c^{\text{'}}=4$ksi.

Grade $60$ steel

NWC$.M_n=?$

$(4.)$

$f_c^{\text{'}}=3$ksi

Grade $60,$ NWC

$M_n=$