A $300500mm$ column, bent about its strong axis in single curvature, has $l_u=5m,k=0\mathrm{.}8,P_u=2225kN,P_D=535kN,M_1=110kN-m,M_2=135kN-m.$ properties are $fc=25$MPa and fy $=420$MPa.

$($a$)$ Assuming bars are placed along two faces with the centers at $40mm$ from the column face, select reinforcement for the column.

$($b$)$ How would the design change if the column was bent in double curvature? $($You do NOT need to select new reinforcement or even do any significant calculations $($although a few may help you explain$),$ just qualitatively describe what would change and why$).$