Re$-$do Problem $5$ above, same information except for sand light$-$weight concrete, $\backslash$lambda $=0\mathrm{.}85,$ and No$.4$ U$-$stirrup $($i$.$e$.,$ Av $=0\mathrm{.}4$ in$^2)$ of Gr$-60$ steel.

$($Problem $5$ states: Per ACI$-318,$ determine shear reinforcement is required for beam B$1,$ when Vu $=50$ kips is present. If required, determine the acceptable spacing of No$.3$ U$-$stirrup $($i$.$e$.,$ Av $=0\mathrm{.}22$ in$^2)$ of Gr$-60$ steel. Take bf $=$

$30"($Note: Use by provided, not the one calculated in Problem $1).)$