overall contract end date.
Two additional challenges were working
within the confines of an active SCPA
wharf and environmental restrictions.
Timely and professional dynamic testing,
as well as innovations to satisfy noise
abatement and close coordination between
pile suppliers, contractor and consultants
proved to be critically important in meeting
these challenges.
Innovation
The noise attenuation requirements were a
first for the Charleston area.
Successful design and use of the
TNAP system was an innovative success
for both SCPA and Cape Romain, as well
as the industry as a whole.
• Pile Hammers - new / refurbished
• Custom Leads - all tubular, pinned style, boom point, fair
leads, fixed / swinging, onshore / offshore
• Accessories - drive caps, cushion material, air line oilers,
air hose, replacement parts
• Sales and rentals of pile driving equipment
• Repair and service of pile driving equipment
Phone: 706-398-1178
Fax: 706-398-1188
www.vulcanhammer.com
Mandrels were designed and constructed
by Cape Romain for both the
vibratory and impact hammer, so that
piles could be taken to grade through the
wharf deck.
Unique application of piles
or design considerations
Unique to this project was an in-situ
dynamic testing program, wherein 35-yearold,
18-inch PSC piles and 25-year-old
24-inch piles were tested, in an attempt to
measure in-place and current capacities,
versus capacities measured when the piles
were originally installed back in the 1980s
and ‘90s.
The resistance increase, by percentage,
ranged from 41 percent to 119 percent. In
certain cases, the initial pile bearing resistance
was calculated at 300kips approximately,
and that was raised to over 600kips,
with the revised allowable pile bearing resistance.
As a result, estimated construction
costs savings was 15 percent of the construction
budget, and/or approximately $9
million dollars. Overall quantities of piles
required were reduced by as much as 35
percent.
Additionally, estimated construction
durations were reduced by 19 percent,
and/or 6 months.
Construction problems
and creative solutions
Noise attenuation specifications posed serious
constructability issues. Most notably,
the noise attenuation requirements placed
severe restrictions on pile driving productivity.
Ultimately, Cape Romain designed
and had approved an insulated steel cylinder
that was employed throughout the
entire water column for all PSC piles. This
noise-attenuation system was proven effective
and far less complex and involved than
the compressed air system recommended
in the specifications.
The end result proved to be greater
pile driving productivity.
Cost saving measures
In-situ dynamic testing carried an initial
cost of $275,000, only 0.4 percent of the
overall program budget. Ultimately, spending
this 0.4 percent initially ending up saving
SCPA 15 percent in construction costs.
This in-situ testing, although rare,
especially in testing piles that are approximately
30-plus years old, proved not only
MARINE: GREATER THAN $5 MILLION
In-situ dynamic testing
carried an initial cost of
$275,000, only 0.4 percent
of the overall program
budget. Ultimately,
spending this 0.4 percent
initially ending up saving
SCPA 15 percent in
construction costs.
116 | ISSUE 4 2017
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