ABSTRACT
For a given shaft diameter d and base diameter db' the above equations help to determine the value of L2. The one that gives the maximum value for L2 has to be used in the design.
Fig. 18.22 gives a typical foundation design with grade beams and drilled piers (Chen, 1988). The piers should be taken sufficiently below the unstable zone of wetting in order to resist the uplift forces.
