Minimum size of RCC column as per IS 456 : 2000 is:

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Question

This question was previously asked in

UPSSSC JE Civil 2018 Official Paper II (Held on 16th April 2022)

Answer 1

Concepts:

The design parameters for an RCC column as per IS 456:2000, provisions are specified below:

For a longitudinal reinforcing bar in a column nominal cover shall in any case not be less than 40 mm, or less than the diameter of such bar.
In the case of columns of the minimum dimension of 200 mm or under, whose reinforcing bars do not exceed 12 mm, a nominal cover of 25 mm may be used.
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. However, where bars from the columns below have to be lapped with those in the column under consideration, the percentage of steel shall usually not exceed 4 percent.
The minimum number of longitudinal bars provided in a column shall be four in rectangular columns and six in circular columns.
The bars shall not be less than 12 mm in diameter.
A reinforced concrete column having helical reinforcement shall have at least six bars of longitudinal reinforcement within the helical reinforcement.
In a helically reinforced column, the longitudinal bars shall be in contact with the helical reinforcement and equidistant around its inner circumference.
Spacing of longitudinal bars measured along the periphery of the column shall not exceed 300 mm.