Page 174 - Civil Engineering Formulas

PILES AND PILING FORMULAS 111

TABLE 4.2 Shape Corrections for Bearing-Capacity Factors of Shallow
Foundations*

Correction factor
Shape of
foundation N N N
c q y

B
B
B
N q
Rectangle † 1 1 tan 1 0.4
L N c L L
Circle and 1 1 tan 0.60
N q
square N c
*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.
where B width of rectangular footing
L length of rectangular footing
e eccentricity of loading
For the other case Fig. 4.2(c), the soil pressure ranges from 0 to a maximum of

2P
q m (4.17)
3L(B/2 e)

b
b

P
M P M

(a) (c) e P
P
e
b
3( – e)
2
p 2
P 1
p
(b) (d)
FIGURE 4.2 Footings subjected to overturning.