COVER FEATURE
WHAT LIES
BENEATH
Pile testing in marine
environments
By Colleen Birchwood
The installation of concrete piles and drilled shafts can
be a complex and challenging task on land. Problems
can arise which result in defects that affect the performance
and the lifespan of a pile. In a marine environment,
construction is even more difficult because of accessibility
issues, which is why pile integrity testing should
be included from the beginning of the production timeline.
“The earlier the better to allow the construction team to
correct deficiencies in a cost-effective manner,” said Paul
Bullock, chief engineer at the Loadtest office of Fugro USA
Land, Inc. “Difficult site conditions are everyone’s problem,
not just the contractor’s. The goal is to provide a reliable
foundation in a timely, cost-effective manner.”
The crux of pile testing in marine foundations, says
Bullock, is that design procedures are semi-empirical, based
on theoretical analysis of complex pile-soil interaction
behaviour, and are modified by research calibrations and
local experience.
“The possibility of unforeseen site conditions is significant,
and a full characterization of the soil mass remains to
be verified during construction. The pile installation process
is a more thorough site investigation than the work done for
design purposes,” he said.
Brent Robinson, the vice-president of Pile Dynamics, Inc.
concurred, “Integrity testing is a test for quality of installation
for new construction – and a test of length and condition
for existing marine projects that are to be reused, expanded
or improved.” Testing helps to predict how the structure’s
foundation will perform in a marine environment as wind,
waves and saltwater can cause unexpected changes to the
pile’s cross-section or cracks in concrete.
PHOTO COURTESY OF FUGRO
PILING CANADA 33