Column can be defined as a vertical building element which transfer compressive load form beam or slab to the foundation and they pramarily use for the purpose of decoration. a column might transfer loads from a ceiling , floor or roof slab or from a beam, to a floor or foundations. Read full article on column.
Types of Columns
Different types of column are discussed below including their function properties:
1. Classical stone columns: This type of columns are often highly decorated, with standard designs including Ionic, Doric and Corinthian, and so on.
2. Steel columns: This column have good compressive strength, but have a tendency to buckle or bend under extreme loading due to the followings;
- Cross-sectional area.
- Method of fixing.
- Shape of the section.
3. Slenderness ratio: This is the effective length of a column in relation to the least radius of gyration of its cross- section. If this ratio is not sufficient then buckling can occur.
Column slenderness can be classified as:
- Long or slender: This is when the length of the column is greater than the critical buckling length. Mechanical failure would typically occur due to buckling. The behavior 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.
4. Short: The length of the column is less than the critical buckling length. Mechanical failure would typically occur due to shearing.
5. Intermediate: This is in between the long and short columns, and its behavior is dominated by the strength limit of the material.
Classification will depend on the column ‘s geometry (i.e. its
slenderness ratio) and its material properties (ie. Young’s modulus and yield strength).
6. Shape: These column can be classified according to their cross sectional shape. Common column shapes include;
In profile, they can be tapered, non-tapered, or ‘barrel’ shaped, their surface can be plain, fluted, twisted, panelled, and so on.
Columns may be of a simple uniform design, or they may consist of a central ‘shaft’ sitting on a column base , and topped by a ‘capital’.
7. Reinforced concrete columns: These columns have an embedded steel mesh (known as rebar) to provide reinforcement.
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 Columns
- Stone column: These column 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: these 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.
- Piers: 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.
- Posts: This is typically used in relation to smaller structural members that may in some cases be independent, rather than part of a wider structure.