Question $2($CLO$1$ and CLO$4)$: Steel Column Design

A structural roof plan for a new single$-$storey office building is shown in Figure $2$ below. The roof loads consist of a superimposed dead load of $5\mathrm{.}0$kPa, a live load of $1\mathrm{.}0$kPa and a snow load of $2\mathrm{.}1$kPa. Note that part of the roof also supports a low$-$intensity green roof with a superimposed dead load of $2\mathrm{.}8$kPa.

Using the factored column resistance tables available in the CISC Handbook of Steel Construction, select an appropriate square hollow structural section $($HSS$)$ for the columns located at gridlines A$-1,$ B$-2$ and at B$-3.$ The total floor$-$to$-$roof height of the building is $6\mathrm{.}75$ metres. Columns can be assumed to be pinned at their base and top. Assume $F_y=350$MPa for columns.