Consider a rectangular slab system for an office building in the figure, which is supported by $400mm$ wide and $600mm$ deep beams. The office is located in Meckering, WA$.$ The concrete has a characteristic strength of $40$MPa in all members. N$12$ D$500$ reinforcement bars are to be used in all slabs, and N$28$ D$500$ reinforcement bars in all beams. The live load is $3\mathrm{.}75$kPa, and the suspended ceilings represent a $0\mathrm{.}15$kPa permanent loading. The permanent load equivalent to partition walls and tiles can be considered as a superimposed dead load on the whole surface of the slabs of $2$kPa. The density of reinforced concrete is $24k\frac{N}{m^3}.$