Types of column
A column is a vertical structural member intended to transfer a compressive load. For example, a column might transfer loads from a ceiling, floor or roof slab or from a beam, to a floor or foundations.
See Elements of classical columns for more information.
See: Colonnade for more information.
- Cross-sectional area.
- Method of fixing.
- Shape of the section.
The cross-sectional area and the section shape are incorporated into a geometric property of section, known as the radius of gyration. This refers to the distribution of an object's components around an axis. It can be calculated:
r = √I/A
Where, I = 2nd moment of area, A = cross-sectional area.
 Slenderness ratio
- Long or slender: The length of the column is greater than the critical buckling length. Mechanical failure would typically occur due to buckling. The behaviour of long columns is dominated by the modulus of elasticity, which measures a column's resistance to being deformed elastically (i.e. non-permanently) when a force is applied.
- Short: The length of the column is less than the critical buckling length. Mechanical failure would typically occur due to shearing.
- Intermediate: In between the long and short columns, and its behaviour is dominated by the strength limit of the material.
In profile, they can be tapered, non-tapered, or 'barrel' shaped, their surface can be plain, fluted, twisted, panelled and so on.
The design of reinforcement can be either spiral or tied.
- Spiral columns are cylindrical with a continuous helical bar wrapped around the column. This spiral provides support in the transverse direction.
- Tied columns have closed lateral ties spaced approximately uniformly across the column. The spacing of the ties is limited in that they must be close enough to prevent failure between them, and far enough apart that they do not interfere with the setting of the concrete.
 Other types of column
Stone columns (or vibro stone columns) are formed by granular aggregate that is inserted into column shaped excavations and then compacted to improve the load bearing capacity of soil and fill material.
Pilotis are supports that lift a building above the ground or a body of water. In timber form, they were traditionally used in the vernacular architecture of Asia and Scandinavia, or wherever indigenous peoples lived at a water’s edge. They may also be used in hurricane or flood-prone areas, to raise the structure above storm surge levels.
The pioneer of modern pilotis was the architect Le Corbusier, who used them both functionally as ground-level supporting columns, and philosophically as a tool for freeing the rigidity of traditional plan layouts, enabling efficient, buildings as 'machines for living'.
See Pilotis for more information.
the term ‘pier’ can be used interchangeably for several different building elements. In general, it is an upright support for a structure or superstructure, but it can also refer to the sections of load-bearing structural walls between openings and different types of column.
See: Piers for more information.
The word 'post' is interchangeable with the word column, although is is typically used in relation to smaller structural members that may in some cases be independent, rather than part of a wider structure.
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