Several types of columns are used in building construction, the effective depth of a column is at the least 3 times its lateral dimension.
The column is a vertical member that carries the load of the structure from beam and slab to the foundation.
Sometimes, the column carries the axial load in compression, it is extremely essential parts of the column structure and failure of the column results in structure collapse.
Different loads corresponding to snow loads, wind loads, horizontal forces or thrusts may cause bending within the column.
Columns are usually constructed from materials such as stone, brick, block, concrete, metal or others that have corrosive strength.
Sometimes, columns carry bending moments at one or both cross-section axes.
Types of Columns used in Construction:
Different types of columns are used in construction industries and they can be classified based on several conditions:
Columns Based on the Shape:
Following are the types of columns based on size:
Square or rectangular columns:
They are generally used within the buildings construction and heavy structures.
Due to the simplicity in shuttering and to preventing it from collapsing due to pressure it is very easy to construct and cast rectangular or square columns, while the concrete is still in the flow able form.
Squares or rectangles are better in cost and cheaper.
Circular columns are mostly used for aesthetic functions within the elevation of buildings.
In a circular column, more than 4 longitudinal steel bars are used as a reinforcement strip and its bending resistance is usually greater than square or rectangular column.
In addition to buildings, round columns are largely used as bridge columns because of good resistance against deflection.
L and T shaped columns:
Generally, L-shaped columns are used in the corners of the boundary wall and have similar characteristics like rectangular or square column.
T-shaped columns are used in the bridges based on the design requirements on large scale construction.
Columns Based on the Type of Reinforcement:
Followings are varieties of columns based on the shape:
This type of column normally constructed from reinforced concrete. Longitudinal reinforcements are closely restricted throughout the tie reinforcement.
If the ties are placed too far, the column will experience the shear failure and intersection between the ties.
It is estimated that 95% of all columns in buildings are tied columns.
When spiral columns are reinforced with spiral reinforcement closely and evenly spread, they are also called spiral columns.
Most spiral columns are provided to support the transverse direction and prevent the column from barring.
Normally reinforced columns usually have 6 bars as longitudinal reinforcement.
These types of columns consist of a structural steel or cast iron column surrounded by concrete, reinforced with longitudinal as well as spiral reinforcement.
Composite columns are widely used in truss structures to avoid corrosion of steel.
This type of column has more adequate strength, with smaller cross-sections, to demonstrate good fire performance.
Columns Based on the Type of Loading:
Following are the types of columns based on loading:
Axially filled columns:
If the vertical axial load acts at center of gravity of the column’s cross-section, it is termed as an axially loaded column.
The axially loaded column is rare in construction because it is not practical to settle the vertical load on the column section’s center of gravity.
The internal column of symmetrical multi-story buildings with floor slabs from each side is an example of this type of column.
Uniaxial Eccentrically Loaded Column:
The axis of vertical load does not cross with C.G. (Center of gravity) of a cross-section of the column, but also acting either eccentrically on the X or Y axis of the column cross-section, is called a uniaxial loaded column.
With this loading system, the column is used in the column that is attached to the beam from one side of the column.
Biaxial eccentric column:
When the vertical load on the column doesn’t coincide with the centre of gravity of the column and doesn’t act on the shock axis (X and Y axis), the column is known as a biaxial eccentric column.
Columns with biaxial loading are principally used in corner columns, with beams rigidly combined at right angles to the top of the columns.
These types of columns are used in particular types of building.
Columns Based on Slenderness Ratio:
Followings are kinds of columns primarily based on slenderness ratio:
If the ratio of the efficient length of the column to the least lateral dimension is lower than 12, then the column is known as a short column.
The crushing of concrete (pure compression failure) causes the failure of a small column.
If the ratio of the effective size of the column to the least lateral dimension is bigger than 12, it’s known as a long column.
A tall column fails by bending or buckling, long columns are weaker than shorter columns of similar cross-sectional area and they are generally not preferred.
Column Based on Construction Materials:
Followings are types of columns based on slenderness ratio:
Reinforced Concrete Columns:
The types of columns that are reinforced with steel are known as reinforced concrete columns.
This type of column is used prominently in building construction, concrete is strong in compression and weak in tension.
Subsequently, steel reinforcement is provided to extend its tensioning capability.
The column made of steel is known as steel column, there are huge trends in steel structure manufacturing in the world.
The steel structure is comparatively more flexible, stronger and durable than the concrete structure.
There are different types of steel columns such as T section steel columns which are most commonly used in steel structure.
The columns made of wood are known as wooden columns, timber columns have been popular in the last century.
Timber is usually seen in old buildings as a result of at that time it is the only building materials which might be readily available.
The timer is a strong and durable construction material if it is given proper treatment, it is used to extract moisture from wood which gives it strength and reduces weight.
Brick masonry types of columns are generally used in load-bearing structures.
It plays an important role in supporting and enhancing the stability of the masonry structure.
Sometimes, the construction of brick masonry columns above the concrete column enhances its aesthetic appearance.
These columns may have different cross-sections such as round, rectangle, square or elliptical.
Block type columns are made of AAC blocks or cement concrete blocks, the block column structural weight is lower compared to concrete columns.
The types of columns made using stone and rubble are known as stone columns.
Most commonly used to improve the aesthetic appearance of a household.
We will build a small-sized structure by random rubble masonry at a certain height, but a multi-story building cannot be constructed by random rubble masonry because the structure is capable of transmitting heavy loads at the base of the foundation.
The column is generally designed to evenly distribute compressed axial loads and additional forces such as ice, wind, and can also be used to maintain the structure in earthquakes or any other forces.