eventually evaporates. After a time, the constant ingress and
egress of water causes sections of concrete to begin slowly
In the case of steel, the material corrodes in marine environments
with some settings being harsher than others.
According to Huckabee, in Alaskan coastal waters “certain
bacteria present in the water can accelerate the corrosion of
steel piles as much as 400 times.”
When corrosion of steel or chipping of concrete is
first observed, the next step is to determine just how
bad the damage is. To do that, the piles first have to be
“After piles have been in water for several years,” said
Huckabee, “you get a lot of marine growth.” The accumulated
growth first has to be stripped away to assess the extent of
the damage to the submerged pile.
“Typically,” said Huckabee, “what happens is a diver goes
down with a pressure washer, not unlike something you’d see
at a carwash, and shoots several thousand psi pounds per
square inch of water to clean a pile.”
However, according to Huckabee, there are several drawbacks
to the existing method. First, it’s an inefficient process.
Dive teams can be slow, especially in water with poor visibility.
There is also the possibility that portions of the pile will
be missed and won’t be properly cleaned during the process.
Second, there are significant safety concerns. “Anytime
someone is submerged under water for an extended period,”
said Huckabee, “that is a potential hazard.”
In most cases where the water is too murky or too deep,
the dive teams are effectively operating blind. This also
increases the likelihood of injury. An added potential cause of
injury is the pressure washer itself. If the diver inadvertently
sprays their self, the pressure required to clean marine piles
is so high that the risk of bodily harm is considerable. This
problem has been addressed by making spray nozzles longer
to reduce the likelihood that divers might spray themselves.
However, longer nozzles limit the diver’s ability to turn and
manoeuvre, and this in turn creates a further hazard.
Third, using dive teams can be costly and labour-intensive.
The work often involves long days with at least five-man
teams and an average cost of $10,000 per day.
“In order to save time, money and dramatically improve
safety,” said Huckabee, “Pilecap started developing an automated
pile cleaning system 15 years ago.”
Pilecap developed a ring-shaped system that clamps
around a pile’s circumference. It can be set up around a pile
by one person in as little as 10 to 15 minutes. Once set up,
it dispenses 15,000 gallons of water per minute through five
nozzles. The machine rotates clockwise and then counterclockwise
back to its original position.
“Nine out of 10 times the pile is cleaned with just one
spin,” said Huckabee. It cleans one 18-inch section at a time
and is then moved down the length of the pile using a track
system. The tracks also have a built-in suspension system so
the clamp ring can expand to pass over especially thick rings
of marine growth.
Pilecap’s forthrightly named “Automated Pile Cleaning
System” represents a significant improvement over existing
diving-based methods. “This is basically five times as
fast as you could get the job done with a dive cleaning time,”
The jets are kept six inches away from the pile itself. For
cleaning steel, Pilecap uses 15,000 psi, which manages to
clean a pile down to bare steel. For concrete, their team uses
8,000 to 10,000 psi.
Pilecap also designed the system so it can be scaled up
or down easily. “The smallest we’ve done,” said Huckabee, “is
12¾ inches and the largest was 57½ inches.”
After a pile is cleaned, the machine operator lets the water
settle and then uses specialized underwater cameras to
assess the pile. “Pilecap has a lot of expertise in inspecting
piles, pipelines, docks, tanks, wharfs and pretty much anything
under water,” said Huckabee.
“The best part of this is that if we clean and inspect them,
we can also repair them. We can usually do two to three pile
jackets per day, up to 25-foot sections. The alternative is that
the client will have to drive new piles,” said Huckabee.
Pilecap effectively offers “one-stop shopping.” For projects
in which clients may have to hire three separate contractors
for cleaning, inspection and repair, Pilecap offers all
Though, it’s been a long process to get the Automated Pile
Cleaning System to where it is today.
“This is the fifth time we’ve been through it,” said Huckabee,
“and it has definitely changed a lot over the years.” The initial
iterations used hydraulics, but proved to be maintenance
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50 Q3 2020 www.pilingcanada.ca