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Hurricane-Durable Composite NEWS Docks
to sustain Category 3 forces — 205-241 kph winds and 2.74-
3.66m of sea storm surge — but also to provide shelter for emergency
response crews and dozens of storm refugees. JFRD had
purchased a new 22m fireboat boat, Marine One, which would be
permanently moored at Station 40 on a new 22m by 2.4m floating
dock. Additionally, a 67m long by 1.8m wide fixed portion of the
new dock structure needed permanent lifts for a 9.14m fireboat
and two same-sized Port Authority security boats.
“The first bids to
build the dock with
reinforced concrete Composites ... were able to
were rejected
meet all the technical and
because they
grant-funding requirements,
were too expensive,”
explains
including budget and timeline.
Register
Marine president
George Register. With all bids 50% over the budget, and no
viable alternatives, the city believed it would have to forfeit the
grant money and abandon plans for the new dock construction.
But then Register found out about the project and met with city
engineers. “We reoriented the program to use composites,” he
says, “and were able to meet all of the technical and grant-funding
requirements, including budget and timeline.”
On schedule, on budget
The fixed and floating docks for the new facility, plus three hoists for small boats,
were finished on budget and with five days to spare.
Saving weight, waste, cost and time
“Designing a dock isn’t rocket science,” concedes Register,
explaining that the basic components of pilings, decking and a
means to connect these are pretty universal. That said, Register
explains that each dock must be designed for its unique loads
and environment. “The Station 40 design cannot just be copied,”
he adds.
Register had been working with pultruded composites in
marine construction for years, including fiber-reinforced plastic
(FRP) pilings, channels and decking. For the St. Johns docks,
Register worked with Stuart LaHaise, president of Composite
Products Plus (Jacksonville, FL, US) and a manufacturer’s representative
for ACRA-LOCK methyl methacrylate (MMA) adhesive
made by Engineered Bonding Solutions LLC (Titusville, FL, US).
He explains, “We developed a system where all of the composite
pultrusions are held together using both ACRA-LOCK structural
adhesive and stainless steel through-bolts.” In the future, Register
would like to eliminate the use of stainless steel fasteners, but for
now, they provide structural redundancy and, for that reason,
were necessary to appease the structural engineer on the project.
Register Marine went through a rigorous design process, working
with structural engineer Dan Charletta of Structures International
LLC (Jacksonville, FL, US), while Dr. Bill Miller, senior coastal and
hydraulics engineer at Taylor Engineering (Jacksonville, FL, US),
completed the numerical modeling and storm force predictions. “It
was important that Dan was amenable to FRP,” says Register.
The real challenge for the Station 40 dock was to meet hurricane
requirements, corrosion resistance, energy absorption and
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