Design of column footing

 

BENDING MOMENT OF COLUMN:-

M = BENDING MOMENT

P = AXIAL LOAD

E = DISTANCE BETWEEN THE CONCENTRATED LOAD AND THE CENTER OF THE COLUMN

M = P × E

    = 534.855 X 0.050  

    = 26.74275 KN.M

 

DESIGN OF FOOTING:-

MAXIMUM DESIGN AXIAL LOAD= 534.855 KN

DESIGN BENDING MOMENT= 26.74275 KN.M

CONCRETE MIX= M20

CHARACTERISTIC STRENGTH OF REINFORCEMENT =550

N/MM2

 

SIZE OF COLUMN= 300 MM × 300 MM

 

SAFE BEARING CAPACITY OF SOIL=100 KN/M2 (ASSUMED)

 

SO, GIVEN COLUMN AXIAL LOAD= 534.855 KN

ADD 10% FOR SELF-WEIGHT= 53.4855 KN

TOTAL= 588.3405 KN

 

 

AREA REQUIRED :-  (TOTAL LOAD / S.B.C)

                              = (588.3405 / 100)

                              =5.8834 M2

AGAIN, WE INCREASE 10% FOR MOMENT

AREA  REQUIRED = 1.10 X 5.8834

                         = 6.4717455 M2

IF WIDTH B,  B2  = 6.4717455  M2

                           = > B = 2.55 M

 

LET US TRY, WITH A SQURE FOOTING OF SIZE 2.6 M X 2.6 M

PMAX = P/A – M/Z

        = {588.3405 / 2.6 X 2.6} - { 26.74275 / (2.6 X 2.6 X 2.6/2)}

        =87.0327-1.721

       = 85.3117 KN/M2 

  (HENCE IT IS SAFE)

 

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