Pile Design and Construction Practice, Fifth edition

Piles to resist uplift and lateral loading 355

R

R

D

Y

X

A

Z B

RA

RC

RB

C

Resultant

Resultant

d

c

a

b

Figure 6.40Graphical method for determining forces on groups of vertical and raking piles

under inclined loading.

R

R D Y

C

X

B

A

Z

a

b

c

d

Resultant

Figure 6.41Graphical method for determining forces on groups of closely spaced vertical and

raking piles under inclined loading.

by Poulos and with results of model tests. Computer programs have been developed to aid
the design of pile groups for these loading conditions. They include the ALP program
previously referred to(6.20). Also DEFPIG developed by Poulos at the University of Sydney
Engineering Laboratory, and PGROUP, available from various bureaux.
The case of closely spaced groups of piles acting as a single unit when subject to lateral
loads must also be considered. Prakash(6.27)showed that piles behave as individual units if
they are spaced at more than three pile widths in a direction normal to the direction of