Calculate the steel requirement:

Another type of problem that a designer faces is to decide the amount of steel required if the column is to support a magnitude of load. For instance, if the column is required to carry an axial load of 960 kN, let us calculate the steel requirement.

Maximum stress in steel = 72 N/mm²

Maximum stress in concrete = 4 N/mm²

Let the area of steel be A_s.

Area of concrete = 160000 - A_s.

∴          72 × A_s + 4 (160000 - A_s) = 960 × 1000

(72 - 4) A_s + 640000 = 960000

∴          A_s =(960000 - 640000)/72 - 4 = 4706 mm²

This might be provided suitably (say, 8 nos of 28 mm dia bars, that will be a little more than enough).