Question $1$:

Required to design a house. The structure of the house will be built from timber. The designer has selected a $4$ m height column at the centre of the house. This column will carry a permanent load of $20$ kN from $30$ m$2$ roof space, wind load of $8$ kN and an imposed action of $4$ kN arising from infrequent crowd loads due to erection and maintenance work. During winter snow falls in this area. The column will get an estimated snow load of $5$ kN$.$ The column will be fixed to the top and bottom by two M$16$ Bolts.

Client has requested to design this column using seasoned hardwood Turpentine timber of F$27$ grade. Client also mentioned that you can use intermediate restraints about the major axis and minor axis at mid height only. Note that short$-$term $($s$),$ long$-$term $($l$)$ and combination factors $($c$)$ can be taken as zero. The column should have a minimum safety factor $1\mathrm{.}5$ for all load combinations. Determine the suitable section size for the column.

Use Australian standards.