Construct the interaction diagram for the column section shown below in Figure $1($for its strong axis$)$ giving that $f_c^{\text{'}}=35$MPa and $f_y=400$ and that all dimensions are in $mm,$ then answer the following questions,

a$)$ Check the column section safety under $P_f=2000kN$ and $M_f=400kN.m.$ If the section is safe, determine the cross$-$section moment capacity at this axial load level. If the section is unsafe,

b$)$ Check the column section safety under $P_f=300kN$ and $M_f=570kN.m.$ If the section is safe, determine the cross$-$section axial load capacity at this moment level. If the section is unsafe, determine the maximum safe $P_f{?}_{?}$ demand at this moment level.