Question

The diameter of longitudinal bars in a column should not be less than

1. 8 mm
2. 10 mm
3. 12 mm
4. 16 mm

Answer 1

Correct Answer - Option 3 : 12 mm

Explanation:

As per IS 456: 2000, clause 26.5.3.1,

Longitudinal reinforcement in a column:

The minimum diameter of longitudinal reinforcement bars:

• The main longitudinal reinforcement bars used in the column shall not be less than 12 mm in diameter.

The minimum number of longitudinal bars:

The minimum number of the longitudinal bar provided in the column shall be

• four in rectangular columns
• six in circular columns

Percentage of steel:

• The cross-sectional area of longitudinal reinforcement shall be not less than 0.8 percent nor more than 6 percent of the gross cross-sectional area of the column.

Helical reinforcement:

• A reinforced concrete column having helical reinforcement shall have at least six-bar of longitudinal reinforcement within the helical reinforcement.

Spacing:

• The spacing of longitudinal bars measured along the periphery of the column shall not exceed 300 mm.