Correct Answer - Option 2 : less than 0.8 per cent and more than 6 per cent of the gross sectional area
As per IS 456: 2000, clause 188.8.131.52,
Longitudinal reinforcement in a column:
Percentage of steel:
The cross-sectional area of longitudinal reinforcement shall be
- not less than 0.8 per cent of the gross cross-sectional area of the column
- nor more than 6 per cent for unlapped bars of the gross cross-sectional area of the column
- nor more than 4 per cent for lapped bars of the gross cross-sectional area of the column
The minimum diameter of longitudinal reinforcement bars:
The main longitudinal reinforcement bars used in column shall not be less than 12 mm in diameter.
The minimum number of longitudinal bar:
The minimum number of the longitudinal bar provided in column shall be
- four in rectangular columns
- six in circular columns.