For the ultimate limit state $($ULS$),$ write all the possible load combinations for column AB$,$ and report the critical case. b$)$ For simplicity, assume that the resistance of the column is AFy, in tension and $0\mathrm{.}75$AFy in compression, where A is the cross$-$sectional area and Fy is the yield strength of the steel. Assuming further that the member is made of steel with Fy $=350$ MPa, use the limit states approach to determine the cross$-$sectional area required.