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Harbor
Project Background
This project is part of an ongoing NFESC Repair and Upgrade Program
to demonstrate advanced technologies for post strengthening of existing
Navy piers. The methodology incorporates the placement of a few
ounces/ft2 (gm/m2) of high strength material in strategic locations
versus massing hundreds of pounds (kgm) of additional concrete and
steel over the entire deck or replacing the superstructure. The
simplicity of the upgrade produces only minimal interruptions in
pier operations as opposed to closing the pier for up to a year
for traditional strengthening. The upgrade program defines and demonstrates
the application of post strengthening using fiber-reinforced plastic
systems to meet demands due to operational changes that were not
included in the original pier design. The program also demonstrates
applied sensor systems that provide measurements of performance.
The Bravo 25 project specifically demonstrated concrete repair and
installation of cathodic protection system with the external reinforcement
in a tropic zone. It represented a significant challenge in coordination
of interdependent tasks on an operational, steel-reinforced concrete
pier.
Scope of Work
The work included concrete repair, cathodic protection installation,
and strength upgrades for selected spans between pile bents 177
and 189 on the west end of the berthing and pile bents 216 to 225
on the east end (Figures 2 and 3). The tasks included:
1. Removing the defunct crane rail on the waterfront edge of
the deck.
2. Repairing damaged and deteriorated concrete on the deck and
track slabs.
3. Sealing existing cracks with silicone.
4. Installing an ICCP system on the bottom of the deck.
5. Embedding pultruded carbon/epoxy rods in the top surface of
the deck.
6. Bonding carbon/epoxy laminate to the bottom of the deck.
The cathodic protection system and the upgrade reinforcing were
designed for a service life of 20 years.
The Navy does not recognize any formal design guidelines or building
code approvals for installing titanium-based cathodic protection
systems or fiber reinforced plastic composites to upgrade reinforced
concrete on maritime waterfront structures. Therefore, it was critical
that the Navy’s quality assurance requirements of the specifications
be met without compromise. NFESC engineers were on the site continuously
to provide quality control of each phase of the construction and
to assist the Resident Office in Charge of Construction (ROICC)
on technical matters.
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