~ ]/ ~

Example 17 .1 A multistory building is to be constructed in a stiff to very stiff clay. The soil is homogeneous to a great depth. The average value of undrained shear strength C

u is 150 kN/m2• It is proposed to use a

drilled pier of length 25 m and diameter 1.5 m. Determine (a) the ultimate load capacity of the pier, and (b) the allowable load on the pier with F

s = 2.5. (Fig. Ex. 17.1)

Solution Base load When C

u ~ 96 kPa (2000 Ib/ft2), use Eq. (17.8) for computing qb. In this case C

u > 96 kPa.