Basic Rules in Column Design | Minimum Column Size | Concrete Cover | Spacing of Lateral Ties | Civil Engineering

The column design is one of the important aspect in building design for construction of any safe structures. While designing the column section we have to follow the basic rules as per the standards which is provided by the code provisions.

These basic rules will helps to create better and safe structure under the consideration of building specifications. The following are the basic rules to be considered before designing of column.

1. Minimum Column size
2. Minimum Diameter of the bars
3. Minimum Grade of the concrete
4. Concrete cover
5. Use square columns
6. Spacing of lateral ties
7. Minimum number of bars
8. Top and bottom area of column
9. Center to center distance 
   
   
   
   

1. Minimum column size

The minimum column size as per code provision is taken as 9”X9” for building structure, depending upon the loading condition and building specification the column size may varies. If the loading on the structure is higher than we have give suitable dimensions of column which is greater than minimum sizes (9”X9”).

2. Minimum Diameter meter of the bars

The minimum diameter is the second basic rule to be considered in building design, as per the code provisions the minimum diameter of bar is taken as12mm. And the maximum diameter is depending upon the design considerations.

3. Minimum Grade of the concrete

Grade of the concrete is nothing but the proportions of ingredients used to make concrete mixture. Basically concrete is a mixture of cement, sand, aggregates, water and admixture if required, the strength of concrete is depends upon the mix proportion of ingredients. As per standard the minimum grade of concrete should be M20 with mix proportion of 1:1.5:3 for building design.   

4. Concrete cover

The concrete cover is the third factor to be considered in building design as per the standards the cover is the 10% the higher dimensions of beam or column. Let us consider an example column which is having 230mmX350mm dimensions the higher dimension of this column is 350mm and 10% of 350 which is 35mm. So the cover of column section is taken as 35mm.

5. Use square columns

The geometry of column is also important aspect in building design for buildings basically we use square, rectangular, circular or polygon sections. But as per the code provisions only use square column section is preferable than other geometry because the loading distribution is even in square column section than other geometry.

6. Spacing of lateral ties

The spacing of the lateral ties is 100mm to 200mm for safe structure design. If we increase the spacing beyond 200mm the column section buckling effect will occur.

7. Minimum number of bars

The number of the bars is seventh factor taken in basic rules in column design. For basic building the 4 number of bars is sufficient as per code provisions.

8. Top and bottom area of column

The cross section of column is taken as same throughout the building structure from bottom to top.  For example if we want to build G+5 building model 18”X18” to be taken as the dimensions of the column the same dimension to be provided from base to sixth floor for the building.

9. Center to center distance

The center to center distance between the columns is also important aspect in column design. The minimum center to center distance is 3m and the maximum center to center distance is 5m to be taken as per the standards which is provided by the code.

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