FEATURE
Static, dynamic and rapid load testing can be performed on CFA
piles in the same way, although routine testing of production
piles is not a routine part of verification as for driven piles.
So, the predictive tools or method that
offers the greatest opportunity for reliability
for your specific project conditions
requires that the method must be
correlated to:
a) The specific ground conditions at the
site, based upon an understanding
of the unique geologic characteristics
and the methods used to quantify specific
soil properties,
b) The specific pile type and installation
methods, including specific details
that can influence the results, and
c) Representative load test results that
provide a reliable measurement of
axial resistance of the pile.
For example, one should not anticipate
that a calculation method that has
been used with great reliability in the
alluvial clays of New Orleans would necessarily
be used with the same reliability
in the Yorktown formation in Norfolk, Va.
or in the coastal sand deposits of Long
Island, N.Y. The geology is different, and
the nature and fabric of the soils are
different. Likewise, a method that has
been demonstrated through load testing
to work quite well in a specific locale
with prestressed concrete piles cannot be
expected to have similar reliability with
steel H or pipe piles in the same conditions
until a base of experience and correlation
with load test results is established.
For example, CPT testing with pore pressure
measurement (CPTu) can be a great
tool for development of correlations of
pile capacity, but if all of the historical
pile test information of specific relevance
to your project has only SPT data then
you cannot expect great reliability with
the CPTu until you evaluate load tests
in similar conditions with CPTu data.
One might consider performing multiple
types of tests with the goal of ultimately
improving the practice by using CPTu.
Fortunately, advances in load testing
afford foundation engineers the opportunity
to make reliable measurements of
axial resistance on full scale piles and on a
project-specific basis. Conventional static
load testing remains the gold standard
for measurement, although even static
load tests can be subject to imperfections
(e.g., Hussein et al, 2012). Dynamic
load testing has become a routine part
of driven pile construction and provides
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