Q$6$: Design a rectangular tied column $($using Interaction Diagram$)$ with bars in four faces to support the following service loads:

$PD=500kN,PL=1000kN$

$MD=100kN,ML=200kN$

$$ Start with $H=60cm$

$$ Use $Fc{c}^{\text{'}}=28$MPa$=4$ksi And $Fy=414$MPa$=60$ksi

$$ Use $010$ diameter for spiral and $25$ bars