Introduction of RCC Column
- The whole structure of a building is comprised of different types of components. The column is one of the most important parts of the Framed Structure. Columns are designed to carry the axial loads in compression.
- The Columns are used all over the world for the decorative as well as structural purpose. The main function of the columns is to transmit the load of the superstructure to the underground strata.
- In this article, you will get to know what are columns, different shapes of columns, types of RCC columns and difference between column and pillar.
What Are Columns?
- Columns are the vertical Structural member which transmits a load of the slab to the foundation. The column is a rigid vertical structural member.
- The effective depth of the column exceeds 3 times the lateral dimension. Generally, column carries the axial loads in the compression.
- The biaxial column is subjected to the axial compressive force are undergoes to Moments on one or both axes.
Factors on which strength of the column depends
- The Shape of the Column
- Size of the Column
- Length of the Column
- Cross-Section of the Column
Types of Columns in Architecture
There are five major order of architectural columns used in the construction are as follows
Different Types of RCC Columns
|Sr.No.||Base of Column||Types of Column|
|1||Classification of the Column based on its Cross Section.||Square Column or Rectangular Column|
|T Shape Column|
|L Shape Column|
|Y Shape Column|
|2||Classification of the Column based on its Loading.||Axially Loaded Column|
|Axially Loaded and Uniaxial Bending Column|
|Axially Loaded and Biaxial Bending Column|
|3||Classification of the Column based on its Length and Behaviour.||Short Column|
|4||Classification of the Column based on its Longitudinal Reinforcement.||Tied Column|
Columns are classified into different types according to the different criteria are as follows
- Classification of the Column based on its Cross Section.
- Classification of the Column based on its Loading.
- Classification of the Column based on its Length and Behaviour.
- Classification of the Column based on its Longitudinal Reinforcement.
The brief description of the classification of columns given as follows
#1. Classification of the Column Based on Its Cross Section.
There are different types of shapes of columns which are used in the construction as per the requirement or design.
- Square Column or Rectangular Column
- Circular Column
- T Shape Column
- L Shape Column
- Y Shape Column
#a. Square Column or Rectangular Column
- Square columns or rectangular columns are commonly used in the construction of buildings.
- The construction of the rectangular or square columns is easier and less costly to cast.
- Square or rectangular columns constructed in most of the building structure.
- Significantly both are having the same components, and it differs based on its architect view.
- This type of column was economically good and easy to do shuttering, placing reinforcement & concrete.
#b. Circular Column
- Circular columns are specially design and widely used in the filing and elevation of the structures.
- Circular columns give a good aesthetical appearance to the structure.
- Circular columns are commonly used in the construction of bridge pillars.
- The circular columns are used when there is no need to construct walls on either side of the column
#c. T-Shape Column
- T-column is used as per the design requirements of the structure.
- Mostly T-Shape columns will be provided along with retaining wall or boundary wall based on the design requirement.
- We knew that the brick or concrete wall-length should not be prolonged more than 6m without placing a column in between.
- If a boundary wall constructed by masonry, then a square or rectangular column is placed in every 6 m. At the same time if it is an RCC type wall, then the column was designed as a T- Shape Column
#d. L-Shape Column
- The L-columns is not commonly used in the structure. It is used at the corner of the frame structure.
- L type column was used in boundary wall construction and used in the turning of metro rail or bridge construction.
#e. Y-Shape Column
- Generally, these types of columns are mostly used for bridge construction.
- The bridge is designed to sustain the dead load of the structure & live load of the vehicle motion, and the load was eventually distributed to the column.
#2. Classification of the Column Based on Its Loading.
There are different types of loading of columns which are used in the construction as per the requirement or design.
- Axially Loaded Column
- Axially Loaded and Uniaxial Bending Column
- Axially Loaded and Biaxial Bending Column
#a. Axially Loaded Column
- Axially loaded columns are subjected to the loading which is acting along the longitudinal axis or centroid of the column section.
- A reinforced concrete column is said to be subjected to an axial load when the line of the resultant thrust of loads supported by the column is coincident with the line of C.G. of the column in the longitudinal direction.
#b. Axially Loaded and Uniaxial Bending Column
- The axially loaded and uniaxial bending column subject to the loads which do not act on the longitudinal axis of the column section.
- If the column is axially loaded then the steel bar provided in any pattern no matter. But if the column is in uniaxial bending it needs to place the steel bar in the two faces parallel to the axis of bending (strong axis).
- In the case of biaxial bending, we need to place the steel bar all the four faces.
#c. Axially Loaded and Biaxial Bending Column
- Biaxial bending of columns occurs when the loading causes binding on the principal Axis simultaneously.
- Biaxial bending of columns occurs when the loading causes bending simultaneously about both principal axes.
- The biaxial bending resistance of an axially loaded column can be represented schematically as a surface formed by a series of uniaxial interaction curves drawn radially from the P axis.
#3. Classification of the Column based on its Length and Behaviour.
There are different types of length and behaviour of columns which are used in the construction as per the requirement or design.
- Short Column
- Long Column
#a. Short Column
- A short column is the one whose ratio of effective length to its least lateral dimension is less than or equal to 12.
- Then it is termed as a short column.
- lef / b ≤ 12, lef = effective length, b = least lateral dimension of the column.
#b. Long Column
- Long Column – A long or slender column is the one whose ratio of effective length to its least lateral dimension is not less than 12.
- Then it is termed as a long column.
- lef / b ≤ 12. lef = effective length, b = least lateral dimension of column.
#4. Classification of the Column based on its Longitudinal Reinforcement.
- Tied Column
- Spiral Column
- Composite Column
#a. Tied Column
A tied column is a column in which the longitudinal reinforcement bars are tied together with the separate small diameter transverse ties which are spaced at some interval along with the column height.
A tied column, shown in the above figure, is a column in which the longitudinal reinforcement bars are tied together with separate smaller diameter transverse bars (ties) spaced at some interval along with the column height.
The cross-sections of such columns are usually square, rectangular, or circular in shape.
#b. Spiral Column
Spiral columns are the columns in which the longitudinal bars are arranged in the circular shape. There is a total of 6 number of bars are used for the longitudinal reinforcement.
In a spiral column, the lateral expansion of the concrete inside the spiral (referred to as the core) is restrained by the spiral.
#c. Composite Column
- A composite column is a column which is made of structural Steel shape or pipe which are surrounded by or filled by the concrete with or without longitudinal reinforcement.
- Composite columns are a combination of two traditional structural forms: structural steel and structural concrete.
- As composite columns were generally developed after steel columns and reinforced concrete columns, their design approach could have been based on either steel or concrete design methods.
Round Column Vs Square Column
The Round column and square column are commonly used column shapes in the construction. The difference between the Round column and square are as follows.
|Sr.No.||Round Column||Square column|
|1||Round columns are symmetric about centroidal Axis.||Square columns have four-axis of symmetry.|
|2||The minimum number of bars which are required in the round columns are 6m.||The minimum number of bars which are required in the square columns are 4m.|
|3||A special type of formwork is required for the construction of Round column.||Simple formwork is required for the Construction of square column.|
|4||The Construction of the round column is expensive as compared to the square column.||The Construction of square column is economical as compared to the round column.|
|5||There are no weak points in the round column due to its circular shape.||The square column has four weak points due to the corner edges.|
|6||Round columns are strong in compression so they can carry more load.||Square columns can carry less load as compared to round columns.|
Pillars Vs Columns
Pillar is a vertical structure which is designed to bear the weight of the building’s roof. Pillar is also widely used as a decorative element in the Buildings.
The column is a structural element which transmits the total load of the structure to the footing and the soil.
Difference Between Pillars and Columns
|1||Column is a structural member which transmit the total load of the superstructure to the underground Strata.||Pillar is the Structural vertical element which is designed to bear the weight of building roof.|
|2||Columns are used to support the load-bearing walls||Pillars are used for the decorative purposes.|
|3||In the construction of columns, steel is used.||Steel is not used in the construction of pillars.|
|4||All columns are not the pillars||All pillars are the columns|
|5||Columns are use to support the load of the component members such as beam and slab.||Pillar can be stand alone or support the roof of the Buildings.|