Examples of composite bars:

One of the practical examples of composite bars is the RCC column, a typical cross section of which is shown in Figure. Here, a 400 mm × 400 mm square cross section of a RCC column is reinforced with 8 numbers of 32 mm diameter mild steel bars.

Taking the Elastic modulii of steel and concrete as E_s and E_c and the modular ratio, m =E_s/E_C as 18, let us find the loads shared by steel and concrete when an axial load of 600 kN is applied on the column.

Area of steel bars, A_s = 8 × (π/4) × 32² = 6434 mm²

Area of concrete, A_c = (400 × 400 - 6434) = 153566 mm²

Modular Ratio,         m = 18

Equivalent Area of Concrete = (153566 + 18 × 6434) = 269378 mm²

Total axial load = 600 kN.

Load shared by concrete = (600/269378) ×153566 = 342.046 kN

Load shared by steel =(600/269378) × 18 × 6434 = 257.954 kN

RCC Column Cross Section

(400 mm × 400 mm with 8 No. of 32 mm MS Bars)