by a load Q that is offset a certain distance (known as the eccentricity) from the center of gravity of
the pile cap. For other projects, there may be property line constraints and the load must be offset a
certain distance (eccentricity) from the center of gravity of the pile cap.
One method commonly used to evaluate an eccentrically loaded pile cap is to use Eqs. 6.12 and 6.13.
It is assumed that the eccentrically loaded cap will cause the piles located under one side to carry a higher
load than as compared to the piles located on the opposite side of the pile cap. The first step in the procedure
is to ignore the piles, assume a rigid pile cap, and use a linear pressure distribution such as shown
in Fig. 6.16. The values of q′ and q′′ are then calculated by using Eqs. 6.12 and 6.13. The final step is to
proportion the pressure to an individual pile, such as shown in Fig. 6.16. A usual requirement is that the
load Q must be located within the middle 1/3 of the pile cap and Eqs. 6.12 and 6.13 are only valid for
this condition. The pile carrying the largest load (i.e., number 1 in Fig. 6.16) must not exceed its allowable
load capacity. Equations 6.12 and 6.13 can be used for an eccentricity in one direction (i.e., across
the width or length of the pile cap) or for an eccentricity in both pile cap directions.