Column Design | Design of RCC Column | RCC Column Size Calculation

Information of Column Design

Important Point

The column is an important vertical structural member in the building that helps to transfer the load of the building to the foundation. It creates a framework that withstands all the load of the structure.

The columns are designed to resist the axial loads and the lateral loads and transfer them effectively to the foundation of the structure.

So, as all the loads from beams, slabs are transferred through the columns, it is important to design strong columns. In this article, we will go through the detailed procedure of design of RCC column as per IS 456:2000. The column is defined as a compression member which has an effective length greater than its least lateral dimension.

Column length is three times the least lateral dimension of the cross-section. The main factors that govern the strength of the columns are their shape, size, and cross-section.

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Design of RCC Column

Let us understand the column design procedure with one example

Design RCC column which is subjected to the axial load of 600 KN and the concrete used is of M-20 grade and steel Fe-500. Provide 1% steel and the factor of safety 1.5

Solution:

Fck = 20 N/mm²

FY = 500 N/mm²

Ag = Gross area of the column

Area of steel in concrete (ASC) = (1/100) x Ag

Area of concrete (Ac) = Gross area of column (Ag) – Area of steel (ASC) = Ag -0.01 Ag

Ac = 0.99 Ag

Pu = Axial load on column

Pu = load on column x Factor of safety

Pu = 600 x 1.5 = 900 KN

Following is the formula that is used for the design calculations of the RCC column for the building as per the IS 456:2000

Pu = 0.4 fck x Ac + 0.67 x FY x ASC

where,

Pu = Axial Load on the column

Fck = Characteristics compressive strength of the concrete

Ac = Area of concrete

FY = Characteristics Tensile strength of Steel

ASC = Area of steel reinforcement

Ac = Ag – ASC

ASC= 0.01 Ag

Ac = 0.99 Ag

Ag = Gross Area of Column

Consider 1% of steel in column

Ac = Ag – ASC

900 x 10³ = 0.4 x 20 x (0.99Ag) + 0.67 x 500 x 0.01Ag

Ag = 79858 mm²

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RCC Column Size Calculation

For the calculation of the RCC Column size it is necessary that we should know essential parameters of the factored load on the column, grade of the steel and concrete used in the column.

The size of the column is calculated as per the load coming on the column from the superstructure. For the construction of the High Rise buildings, the size of the column is increased. The size of the column is a key factor that is considered for the designing of any structure.

Different sizes of the columns that are used in the designing of the buildings are as follows

9” x 9”
9” x 12”
12” x 12”
12″ x 15″
15″ x 18″
18″ x 18″
20″ x 24″

The minimum size of the column should not be less than 230 mm x 230 mm.

The more size of the columns can also be used depending upon the structural loads.

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For RCC Column size calculation following data is required

Grade of Concrete
Grade of Steel
Factored Load on Column

Shape of the column = square shape

Size of column = √ 79858 = 282.59 mm

So, providing the size of the column 285mm x 285mm

Gross Area provided = ( 285 mm x 285 mm ) = 81225 mm²

Area of steel provided in concrete (ASC) = 0.01 Ag

ASC = 0.01 x 81225

ASC= 812.25 mm²

Provide 8 nos 12 mm diameter of reinforcement bars having area of steel = 905 mm²

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RCC Column Design

Diameter of lateral ties as per the IS 456:2000

¼ x Diameter of larger bars = ¼ x 12 = 3 mm
8 mm

Provide larger of the above two values that is provide 8 mm diameter of the lateral ties

The pitch of the lateral Ties as per the IS:456

Least lateral dimension = 285 mm
16 x Diameter of the smaller reinforcement bars = 192 mm
300 mm

Provide smaller whatever is of the above three values

Provide pitch = 190 mm

Provide 8 mm diameter of lateral ties at the 190 mm of center to center distance.

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FAQ

Beam Column

Structural members subjected to axial compression and bending are known as beam columns. The interaction of normal force and bending may be treated elastically or plastically using. Equilibrium for the classification of cross-section.

A Column

A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. Columns are frequently used to support beams or arches on which the upper parts of walls or ceilings rest.

Column

The definition of a column is a vertical arrangement of something, a regular article in a paper, magazine or website, or a structure that holds something up. An example of column is an excel list of budget items. An example of column is a weekly recipe article.

Rcc Column

a reinforced concrete column is a structural member designed to carry compressive loads, composed of concrete with an embedded steel frame to provide reinforcement.

Different Types of Columns

Types of Columns In Civil Engineering

Square or Rectangular Column
Circular Column
L and T shaped Column
Tied Column
Spiral Column
Composite Column
Axially Loaded Column
Uniaxial Eccentrically Loaded Column

Column in Construction

Column Covers

Column cover systems. Help cover unsightly beams or concrete columns to offer a finished and durable appearance. Column covers can be manufactured out of plate or composite material in various finishes and textures.

Column Base

A column base consists of a column, a base plate and an anchoring assembly. In general they are designed with unstiffened base plates, but stiffened base plates may be used where the connection is required to transfer high bending moments.

Building Column

Column is a vertical structural member that carry loads mainly in compression. It might transfer loads from a ceiling, floor slab, roof slab, or from a beam, to a floor or foundations. Commonly, columns also carry bending moments about one or both of the cross-section axes. Types of columns in building construction.

Composite Column

Composite columns are a combination of two traditional structural forms: structural steel and structural concrete. As composite columns were generally developed after steel columns and reinforced concrete columns, their design approach could have been based on either steel or concrete design methods.

Rcc Column Reinforcement Details

As per IS code, the minimum dia of the longitudinal bar should not be less than 12 mm, and the dia of a stirrup should not be less than 8 mm. Stirrup should be placed at a distance of 150 mm (centre to centre distance).

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