How to calculate load carrying capacity of the column

Example:

    Load = 400 kN

    Column size = 300mm×300mm

  No of steel bar used in column 4 nos

Diameter of bar used in column = 16mm

M20 grade concrete used 

Grade of steel = Fe 415 

  Formula:

     

     Pu = (0.4fck.Ac)+(0.67fy Asc)

   ( From IS-456 2000 code page no 71)

Where .

     Pu = axial load on the member

     Ac = area of concrete 

    fck = characteristic compressive 

              strength of the concrete 

      fy = characteristic strength of the

              compression reinforcement 

   Asc = area of longitudinal reinforceme

              -nt for column

      fck = 20

        fy = 415 

    Ac = Ag-Asc

    Ag = gross area of column 

    Ag = 300×300 mm square 

          = 90000 mm square 

   Asc = 4×((3.14×16×16)÷4) mm square 

           = 804.24 mm square 

    Ac = (90000-804.24) mm square 

          = 89196 mm square 

   Pu = (0.4×20×89196)+(0.67×415×804)

         = 937120.1 N

         = 937.1 kN ans.

According to the IS-456 2000 

Safety of factor = load /1.5

                               = 624.74 kN

Note: for more information watch video link below. 

https://youtu.be/pFDmAt0EWvE