Column in construction | Types of columns | History | Importance of columns

 Column

Columns come in a variety of shapes and sizes, and they are employed in many portions of structures. A column is a vertical structural element that mostly carries compression loads. It may carry loads to a floor or foundations from a ceiling, floor slab, roof slab, or beam. Columns commonly have bending moments along one or both cross-section axes. Different types of columns used in building construction will be described in this article.

Column Types in Building Construction Columns are classed depending on a number of factors, including:

1.       Based on Shape

2.       Based on Construction Material

3.       Based on Types of Reinforcement

4.       Based on Types of Loading

5.       Based on Slenderness Ratio

1.     Based on Shape

A.      Column, Square or Rectangular

They're commonly employed in the construction of structures. Because of the ease of shuttering and supporting it from collapsing owing to pressure while the concrete is still in flowable condition, rectangular or square columns are easier to design and cast than circular ones.

B.      Circular column

They are particularly built columns that are typically utilised in piling and construction elevation.

C.      L-Shape Column

L-shaped columns are commonly used at the corners of boundary walls and have qualities comparable to rectangular or square columns.

D.      T-Shape column

It is used in accordance with a structure's design criteria. The T-shaped column is commonly utilised in bridge construction.

E.       Shape of Steel Column

Steel columns come in a variety of conventional and built-up shapes, Steel columns come in a variety of shapes, including I, channel, equal angle, and T-shape.

 

2.     Based on Construction Material

Based on the Type of Construction Based on the materials used in their construction, there are several different types of columns. Such as Reinforced Concrete, Steel, timber, Brick, Block, and Stone Column.

 

3.     Based on Types of Reinforcement

A.      Tied Column

Reinforced concrete is typically used to construct this sort of column. Longitudinal reinforcement is contained within tie reinforcement that is tightly spaced. It is estimated that 95% of all construction columns are tethered.

B.      Spiral Column

Spiral columns are also made of reinforced concrete. Longitudinal bars are restricted within spiral reinforcement that is tightly spaced and continually wound in this form of column. Spiral reinforcement prevents axial load failure by providing lateral restraints (Poisson's effect) (ductile).

C.      Composite column

A composite column is one that has longitudinal reinforcement in the form of structural steel sections or pipes with or without longitudinal bars. This type of column has a high strength to weight ratio and a short cross section, as well as exceptional fire resistance.

4.     Based on Types of Loading

A.      Axially Loaded Column

An axially loaded column is one that has vertical axial loads acting on the centre of gravity of the cross-section of the column. Because it is not possible to align vertical loads on the centre of gravity of the column cross section, axially loaded columns are uncommon in construction. This sort of column can be seen inside multi-story buildings with symmetrical loads from floor slabs on all sides.

B.      Column with Uniaxial Eccentric Loading

Uniaxially eccentric loading columns occur when vertical loads do not correspond with the centre of gravity of the column cross section, but rather act eccentrically on the X or Y axis of the column cross section. Columns having uniaxial loading are commonly found in edge columns, which are rigidly linked to the beam from just one side.

C.      Column with Biaxial Eccentric Loading

The column is called biaxially eccentric loaded when the vertical on the column does not coincide with the centre of gravity of the column cross section and does not act on either axis (X and Y axis). Corner columns with beams firmly joined at right angles at the top of columns are common examples of biaxially loaded columns.

5.     Based on slenderness ratio

Using the Slenderness Ratio as a guide Columns are classified as follows based on the slenderness ratio (effective length/least lateral dimension):

A.      Short Column

The column is referred to as a short column if the effective length of the column to the least lateral dimension is less than 12. The failure of a short column is due to crushing (pure compression failure).

B.      Long Column

A long column is defined as one in which the effective length of the column exceeds the least lateral dimension by a factor of 12. Bending or buckling is how a long column fails.

History of column

Early columns were made of stone, some of which were made from a single block. The largest stones used in architecture are monolithic columns. Other stone columns are made up of several stone sections that have been mortared or dry-fitted together. Sectioned columns were cut with a central hole or dip in several classical sites so that they could be fastened together with stone or metal pegs. Most classical columns include entasis (a tiny outward bend in the sides) as well as a decline in diameter throughout the column's height, with the top being as little as 83 percent of the bottom diameter.

This reduction simulates the parallax effects that the eye expects to see, making columns appear taller and straighter than they are, with entasis enhancing the illusion.

Columns have flutes and fillets that run up the shaft. The flute is the section of the column that has a semi-circular indentation. The section of the Ionic order columns between each of the flutes is known as the fillet of the column. All tapered columns' flute width changes as they progress up the shaft, while non tapered columns' flute width remains constant. This was done to provide aesthetic interest to the columns.

The only orders with fillets and flutes are the Ionic and Corinthian. There are no fillets in the Doric style, but there are flutes. The fillets on the Ionic and Corinthian order columns link the Doric flutes to a sharp point.

 

Importance of column

Columns, like beams, are used for structural reinforcement. In essence, columns are vertical structures that carry compressive loads.

Columns support the floor and the columns on the floors above it; the bottom floor's columns must be large enough to carry the weight of each floor above it. They can transfer loads from the slab and beams to the foundations and soil below.

If at all possible, columns should be positioned similarly on all floors to provide the most efficient support. This would increase the stability of the lowest group of columns.

Structural engineers must measure the weight supported by the column before choosing a suitable design. The vertical forces extruding load values will determine the column design, just as they do with beams. The impact of lateral forces due to earthquakes and wind must be considered while determining the column size and dimensions. There are two main materials utilised in modern column construction:

·         Steel

·         The concrete

Steel columns can be classified into three types: C-section, I-section, and hollow section.

Concrete columns can be made in either rectangular or circular shapes.

Composite columns constructed of steel and concrete are utilised in multi-story structures where the loads on the columns are extremely high.

Columns and beams have been utilised in construction since antiquity. The ancient Egyptians realised the significance of these supports, and the modern column-beam-slab system evolved from the first simple beams and columns.

The foundation would eventually collapse if it did not have beams and columns to support its weight.

 

 

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