Question $3(15$ marks$)$

$($a$)$ A senior structural engineer estimated that the ultimate limit state $($ULS$)$ axial

force in column in a building is $F_x=294\mathrm{.}7kN$ and there are no design

moments. The column is $4\mathrm{.}5m$ in length and is assumed to have pinned

connections at each end. The senior structural engineer has completed some

preliminary calculations that suggests a $152152$ UKC$23$ steel section of grade

S$275$ may be adequate. You are required to check the adequacy of this

section for:

$($i$)$ Local buckling

$($ii$)$ Cross$-$sectional resistance

$($iii$)$ Member buckling capacity in compression

$($iv$)$ Combined shear and bending

$(12$ marks$)$

$($b$)$ If the section size suggested by the senior engineer is not adequate,

recommend a suitable section size $($provided calculations to justify your

recommendation$).$

$(3$ marks$)$