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Basic rule for Design of concrete column



Basic rule for Design of concrete column
the basic rules for design of the column. These basic rules should be remembered while designing the column member. Some of these rules are given below.
First of all the scale of the columns depends on the full load on the columns.
1. Concrete strength should not be less than 20 MPa or 3000 psi.
2- Minimum size of AN RCC column shouldn't be but 9”x 9” (225mm x 225mm) with four bars of 12mm Fe500 Steel.
3- Use Minimum M20 Grade concrete in rcc column (ratio 1 part Cement :1.5parts Sand : 3parts Aggregate with 0.5 parts water by volume)
4- With thumb rule a column span of up to 5 meters is quite safe.
5- Column longitudinal bars should not be less than 12mm and also its should be not more than 50mm by thumb rule.
6- For using steel in column the cross-sectional area of longitudinal steel in a column shall not be less than 0.8 and also its should be not more than 6% of the gross-sectional area of the column.
7- I recommend use of 8mm stirrups at a distance of 150mm center to center throughout the length of column.
8-Diameter of the helical reinforcement: The diameter of the helical reinforcement shall be not less than 1/4th the diameter of the largest longitudinal bars and in no case less than 5 mm.
9- long columns :When the ratio of the effective length and the least lateral dimension of a column exceeds 12, the column will be considered as long column.
10- at least 4 no of bars be used in rectangular column and 6 no of bars be used in circular column.