For Problems $9\mathrm{.}16$ to $9\mathrm{.}18,$ design columns for axial load only for the conditions described. Include the design of ties or spirals and a sketch of the cross sections selected, including bar arrangements. All columns are assumed to be short and not exposed to the weather. Form sizes are in $50-mm$ increments.

Problem $9\mathrm{.}16$ Square tied column: $P_D=600kN,P_L=800kN,f_c^{\text{'}}=24$MPa, and $f_y=420$MPa. Initially assume ${}_g=0\mathrm{.}02$

Problem $9\mathrm{.}17$ Smallest possible square tied column: $P_D=700kN,P_L=300kN,f_c^{\text{'}}=28$MPa, and $f_y=300$MPa. $($One ans. $250-mm250-mm$ column with $6$ #$29$ bars$)$

Problem $9\mathrm{.}18$ Round spiral column: $P_D=500kN,P_L=650kN,f_c^{\text{'}}=35$MPa, and $f_y=420$MPa. Initially assume ${}_g=0\mathrm{.}03.$

$9\mathrm{.}16$: Use number $22$ longitudinal bars. Use concrete cover to center of longitudinal $=70mm$ after verifying it is suitable.

$9\mathrm{.}17$: Use side cover to longitudinal bars $=70mm,$ after verifying the dimension is suitable.

$9\mathrm{.}18$: Use No$.16$ bars

Include longitudinal profile of column reinforcement for each column.