According to IS: 6403 - 1981, what will be the value of the multiplier of the size with respect to the consistency for the square base?

According to IS: 6403 - 1981, what will be the value of the multiplier of the size with respect to the consistency for the square base? Correct Answer 1.2

Concept:

IS: 6403 – 1981 code of practice is used for the determination of bearing capacity of the shallow foundation.

In this code a modification was done on ultimate bearing capacity formula which was first given by Brinch Hansen and known as Brinch Hansen’s method. The modifications take in to account, the shape of the footing, inclination of loading and depth of embedment and effect of water table.

The modified bearing capacity formulas for strip footing are given as under;

Qnu = cNcScdcic + q(Nq – 1)sqdqiq + 0.5γBNγsγdγiγWγ

Where,

qnu= Net ultimate bearing capacity of footing

Sc,Sq,Sy =shape factor

dc,dq,dy = depth factor

ic,iq,iy     = inclination factor

Nc,Nq,Ny= Bearing capacity factor

C = Cohesion

B = breadth or diameter in formula

W’= Correction factor for the location of water table

Sr. No.

 Shape of Bars

Shape Factor

se

sq

i)

Continuous strip

1.00

1.00

1.00

ii)

Rectangle

1 + 0.2 B / L

1 + 0.2 B / L

1 – 0.4 B / L

iii)

Square

1.3

1.2

0.8

Iv)

Circle

1.3

1.2

0.6

 
From the above table, we can see that the shape factor of square base for consistency is 1.2

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