How to Calculate Column Size for Building?

Hello Om, I saw you asking how to decide column size and can help you with it. Being from the architectural line, I am aware of the process, which goes through in determining the column size.

How do you Determine the Size of a Column?

The size of the column is mainly determined by the load, which comes on the column from the slab and beam. When talking about high-rise buildings, the column size increases, which transfers the load of the structure above to below and then to the foundation. 

As per Clause No: 39.3 Page No: 71 IS 456:2000, the formula for calculating the column size is,

Pu = 0.4 fck Ac + 0.67 fy Asc

Pu = Axial Load on Column

fck = Characteristics compressive strength of concrete

Ac = Area of Concrete

fy = Characteristics Tensile strength of concrete

Asc = Area of Steel Reinforcement

Asc = 0.01 Ag

Ac = Ag – Asc

Ac = 0.99 Ag

Ag = Gross Area of Column

Ac = Ag - Asc

Let me also share the minimum standard column sizes according to the building type with you.

This is all from my side about how to calculate size of column. I hope this helps you.

The weight that the column will sustain, the strength of the concrete, and the requirements of the building code are taken into account when determining how to calculate size of column.

When an axial load of 310kN is given to each column, the minimal column size for a 5m span, using M20 grade concrete ratio (1:1.5:3) and Fe500 grade steel, is 230mm by 230mm (9′′ by 9′′). This is in accordance with column design and the thumb rule.

How do you determine the size of a column?

• Establish the weight that the column will be able to support:

This includes any live loads, such as people and furniture, as well as the weight of the structure above the column. A structural analysis program or employing a structural engineer can be used to determine the load. 

• Pick the right concrete strength:

The size of the column will depend on the concrete's strength. The size of the column can be reduced the stronger the concrete is. Typically, the building code specifies the concrete strength.

• Utilize a column design formula to determine the column size:

To determine the minimum column size, a formula will be used that takes into account the load, the concrete's strength, and the requirements of the building code.

The following formula for how to measure column size from IS 456:2000 is,

Pu = 0.4 fck Ac + 0.67 fy Asc

Where,

Pu = Ultimate Load on Column

fck = Characteristics compressive strength of concrete

Ac = Sectional Area of Concrete

fy = Yield strength of steel

Asc = Area of Steel Reinforcement

Ac = Ag – Asc

Asc = 0.01 Ag (Ag = Gross Area of Column)

Ac = 0.99 Ag

After determining the column size, you can order the necessary supplies and start constructing. In order to determine how to calculate size of column for your project precisely, it is always preferable to consult with a structural engineer.

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Hey,

Buildings are constructed with RCC concrete slabs. The columns act as a strength reinforcement in the building. It is necessary to know how to calculate column size for building. Columns, joints, and slabs are a load-bearing structure in the superstructure of the apartment project. Axial loads and lateral columns are constructed according to the number of floors etc. 

Many technologies offer building column size calculators. This is the same for residential and commercial buildings. 

Let's assume the column is a 5metre span for a G+2 building. The column is constructed based on IS code 456:2000.

• You need to find the minimum clear cover of the column to find the size of the column. 

• If the size of the column is less than 200mm, then the clear cover should be 25mm.

• You will need to add the diameter of the column with the dia of Stirrup.

• I will give an example below :

• The minimum diameter should be taken as bar 4 nos of 12mm 

• The minimum area of Steel is 0.8%of Ag

• The maximum area of Steel=6%of Ag ( Steel should not overlap) 4%of Ag if steel is overlap. 

• The spacing between two columns should not be more than 300 mm

• Minimum dia of Stirrup 1/4×16 greater

• The maximum spacing of the stirrup should be 16D, B and the minimum spacing should be 300mm 

Usually, the building column is 9”x9” for a single-story (G+0) structure with M20 (1:1.5:3) concrete. 

This is all from the end on how to calculate column size for building.

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