Question 13.6: The column section whose ratio g=0.7 is shown in Figure 13.1......

Chart RC2f25-7 in the design charts at the end of the book will be used for g = 0.7 and f’_c = 25 MPa.
Stresses due to design loading,

{\frac{N^{*}}{b D}}={\frac{1850\times10^{3}}{400\times400}} = 11.56 MPa

{\frac{M^{*}}{b D^2}}={\frac{160\times10^{6}}{400\times400^2}} = 2.5 MPa

Enter Chart RC2f25-7 and read the required steel ratio p = 0.022.

Required area of reinforcement,
A_s = p \ b \ D = 0.022 × 400 × 400
= 3520 mm²
Choose 6N28 bars (3 bars on each face) whose area is 3720 mm².