Basic Rule For Design Of Column
First of all the size of the columns depends on the total load on the columns.
1: Minimum size of an RCC column should not be less than 9”x 9” (225mm x 225mm) with 4 bars of 12mm Fe500 Steel.
2: Use Minimum M20 Grade concrete in RCC column (ratio 1 part Cement : 1.5 parts Sand : 3 parts Aggregate with 0.5 parts water by volume)
3: With thumb rule a column span of up to 5 meters is quite safe.
4: Column longitudinal bars should not be less than 12mm and also its should be not more than 50mm by thumb rule.
5: 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.
6: I recommend use of 8mm stirrups at a distance of 150mm center to center throughout the length of column.