FEATURE
Axial Resistance of
Drilled and Driven Piles
By Dan Brown, P.E., D.GE, M.ASCE, Dan Brown
and Associates
Since the beginning of our profession,
foundation engineers have
tried to develop better methods
of predicting the axial resistance of
piles with only limited success. New and
more sophisticated in-situ test methods
have been developed, and even complicated
computer models have been tried
but load test results invariably provide
surprises. Although the problem seems
relatively simple, the actual condition
and state of stress in the soil around a
pile after installation involves a complex
series of time-dependent changes in the
ground associated with the pile installation.
Subtle variations in the soil grain
size distribution and the pile installation
technique can have profound implications
(especially with drilled foundations).
Since the effects of pile installation
are so different between driven and
drilled foundations, it is important to
understand, at least qualitatively, what
happens in the ground and at the pile/soil
interface during pile installation.
Background: natthanim / 123rf
Five photos on this page courtesy of David Schoen, S&ME www.piledrivers.org PILEDRIVER | 61
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