Example of Stresses in Composite Bars:

We can get stress in concrete = 342.046 × 1000/153566 = 2.227355 N/mm².

Thus,  Stress in steel = 18 × 2.227355

= 40.0924 N/mm².

In order to compute the load carrying capacity, we needed to know the strength (allowable stress) of all the elements. For instance, let the allowable stress in concrete be 4 N/mm² and the allowable stress within steel be 120 N/mm². There is another restriction, you can remember, that even by the strength of steel is 120 N/mm², we cannot stress it to the full, since if we stress steel to its full strength, i.e. 120 N/mm², then concrete will be stressed to 6.667 N/mm², i.e. 120/18, that is not permissible. Therefore, the maximum stress in which may be induced in steel is only 72 N/mm², i.e. 4 × 18.

Now, we could compute the maximum load the column could support or the load carrying capacity of the column as follows:

P = σ_s × A_s + σ_c × A_c

= 72 × 6434 + 4 × 153566

= 1077512 N or 1077.512 kN.