Please solve with all steps

The column shown below is $15-ft$ tall and has lateral support at both ends only. The Steel

shape used is HP$12$x$84$ and the reinforcing bars are $4$#$9.$ The ties are #$3$ spaced at $10-$

inch on centers. The steel yield stress is $f_y=50$ksi, and the concrete compressive

strength, $f_c^{\text{'}}=7$ksi. Grade $60$ reinforcing bars are used. Assume a concrete cover of $2\mathrm{.}5$

in$.$ to the center of the longitudinal reinforcement. Use the AISC$-$LRFD and determine the

maximum service live load, $P_L,$ if the service dead load, $P_D=750$kips.