Q$2$ Use EC $3$ to check the Composite column for:

$($a$)$ Axial Compression Resistance

$($b$)$ Axial Buckling Resistance

Design data:

Design Load $N_{Ed}=3500kN$

fy $=355\frac{N}{m}{m}^2,$ fck $=25\frac{N}{m}{m}^2,$ fsk $=500\frac{N}{m}{m}^2$

Cross$-$section

Composite Column $350mm350mm$

Steel section: $254254$ UC$73.$

Column length: $5\mathrm{.}0$ m

Reinforcement $4$ bars of Dia $20$ mm

Figure $2$ Composite Column Cross$-$section