Structural Design of Drilled Shafts.

Most drilled shaft foundations will be subject to lateral loads, bending moments, and shear stresses in addition to compressive stresses frorn vertical loads. Eccentrically vertical applied loads can generate additional bending moments.

a. Eccentricit.  If bending moments and shears are not specified, the minimum eccentricity should be the larger of 2 inches or O.1 Bs, where Bs is the shaft diarneter, when tied cases of reinforcement steel are used and 1 inch or O.05Bs then spiral cages are used. The rninimum eccentricity should be the maximum perrnitted deviation of the shaft out of its plan alignment that does not require special computations to calculate the needed reinforcement if larger eccentricities are allowed.


b. Design example. Table 2-7 describes evaluation of the shaft cross section and percent reinforcement steel required for adequate shafi strength under design loads.....