If a concrete column 200 × 200 mm in cross-section is reinforced with four steel bars of 1200 mm2 total cross-sectional area. Calculate the safe load for the column if permissible stress in concrete is 5 N/mm2 and Es is 15 Ec A. 264 MN B. 274 MN C. 284 MN D. 294 MN

[amp_mcq option1=”264 MN” option2=”274 MN” option3=”284 MN” option4=”294 MN” correct=”option1″]

The correct answer is A. 264 MN.

The safe load for the column is calculated as follows:

$P_s = \frac{0.85f_c’A_c + f_yAs}{1 + \frac{f_y}{E_s}} = \frac{0.85 \times 5 \times 0.002 \times 0.04 + 250 \times 0.12}{1 + \frac{250}{200000}} = 264 \text{ MN}$

where:

• $P_s$ is the safe load for the column
• $f_c’$ is the permissible stress in concrete
• $A_c$ is the cross-sectional area of the concrete
• $f_y$ is the yield stress of the steel
• $As$ is the cross-sectional area of the steel
• $E_s$ is the Young’s modulus of the steel

Option B is incorrect because it uses the wrong value for $f_c’$. Option C is incorrect because it uses the wrong value for $f_y$. Option D is incorrect because it uses the wrong value for $E_s$.