Different types of columns

Column :-

   A column is a vertical structural member intended to transfer a compressive load. For example , a column might transfer load from ceiling , floor or roof slab , or from a beam ,to a floor or foundation.

  Column are typically constructed from material such as stone, brick, block, concrete ,timber ,steel, and so on , which have good compressive strength.

  Commonly column also carrying bending moment about one or both of the cross sectional axes . in this article different types of column used in building construction will be discuss.

 Types of column in building construction
      
Column are based on several condition:-

• Based on type of reinforcement
• Based on type of loading
• Based on slenderness ratio
• Based on shape
• Based on construction material

Based on type of reinforcement

1.  Tied column
2. Spiral column
3. Composit column

1) Tied column :-

  This type of column is  commonly construction from reinforcement concrete longitudinal reinforcement are  confined with closely  spaced tie reinforcement. It is estimated that 95℅ of all column in building are tied.

2) Spiral column :-
   Spiral column is also construction from reinforced concrete. In this type of column , longitudinal bars are confined  within closely spaced  and continuously wound spiral reinforcement
   Spiral reinforcement  provide lateral restrain ( Poisson's effect)  and delay axial load failure (ductile).

3) Composite column:-
   When the longitudinal reinforcement  is in the form of  structural steel section or pipe with or without longitudinal bars , it is called as a composite column .
    This type of column have high strength with fairly small cross - section , in addition to  exhibit good fire performance.

Based on types of loading :-

1)Axially loading column
2) column with uniaxially eccentric loading
3) Column with biaxial eccentric loading.

1) Axially loading column :-
  If vertical axial load  acts on the centre of gravity  of the cross section load , then it is termed  as axially loaded column.
       Axially loaded column is rare in construction  since coinsiding  vertical load on  the centre of gravity  of column cross sectional  is not practical .
   Interior column of  multy storey building wih symmetrical  load from floor slab from all side of this type of column.


2) Column with uniaxial eccentric loading :-
When  vertical load do not coincide with center of gravity of column  cross section but rather act eccentrically  either on X or Y axis of  the column cross section , then it is called uniaxial eccentric loading.
      Column with uniaxial loading  are generally encountered in the case of column  rigidly connected  beam from one side only  such as edge column.

3) Column with biaxial eccentric loading 
   When vertical load do not coincide with center of gravity of column cross sesection and does not rather act eccentrically either on ( X and Y axis) ,then it is called as biaxial eccentric load .
   Column with biaxial loading is common in corner of column with beam rigidly connected at right angle at the top of column.

Based on slenderness ratio :-  
   1) Short column.
   2) long column .

1) Short column
   If the ratio effective length of the column to the least lateral dimensions is less than 12 ,the column is called as the short column.
      A short column fails by crushing ( pure compression failure ).

2) Long column .
  A column so slender that it will fail under longitudinal load by bending rather than by crushing and typically having a length of 20 to 30 times the diameter.

Based on shape :-
  1) Square or rectangular column
  2) Circular column .
  3) T - shape column
  4) L - shape column

1) square or rectangular column :-
  They are generally used in the construction of building , it is much easier to construct and cast rectangular or square column than circular ones because of ease of shuttering and to support it from collapsing due to pressure while the concrete is still in flowable form.

2) Circular column :-
  They are specially designed column , which are mostly used in pilling and elevation of the building .

3)  L - shape column 
  Commonly , L shaped column is utilized in the corner of the boundary wall and has similar characteristics of a rectangular or square column .

4) T - shape column .
  It is used based on design requirements of a structure . T shaped column is widely used in the construction of bridge.