= of

Uplift Capacity of Single Pier (straight edge) For a drilled pier in cohesive soil, the frictional resistance may expressed as (Chen and Kulhawy, 1994)

Pa

(17.41a)

(17.41b)

where, a = adhesion factor C

u = undrained shear strength of cohesive soil

P a

= atmospheric pressure (101 kPa) Poulos and Davis, (1980) suggest relationships between Cu and a as given in Fig. 17.23. The

curves in the figure are based on pull out test data collected by Sowa (1970).