CIVIL ENGINEERING FORMULAS

PILES AND PILING FORMULAS 111

whereBwidth of rectangular footing
Llength of rectangular footing
eeccentricity of loading

For the other case Fig. 4.2(c), the soil pressure ranges from 0 to a maximum of

qm^2 P (4.17)

3 L(B/2e)

TABLE 4.2 Shape Corrections for Bearing-Capacity Factors of Shallow

Foundations*

Correction factor

Shape of

foundation Nc Nq Ny

Rectangle†

Circle and

square

0.60

*After De Beer, E. E., as modified by Vesic, A. S. See Fang, H. Y., Foundation

Engineering Handbook, 2d ed., Van Nostrand Reinhold, New York.

†No correction factor is needed for long-strip foundations.

1 ^1 tan



Nq

Nc

1 0.4

B

L

1 

B

L

1  tan 

B

L

Nq

Nc

p

(b) (d)

(a) (c)

P

b

b

P M M

P P

P 1

p 2

e

e

b

3( – 2 e)

FIGURE 4.2 Footings subjected to overturning.