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May 9, 2017

Community Award

Photo courtesy of WACA
The dock required a concrete mix that would hold up against saltwater and high humidity.

USS Arizona Memorial dock replacement

Location: Honolulu, Hawaii

Owner/developer: National Park Service

Team: Hawk Contracting Group, general contractor; Bellingham Marine Industries, concrete contractor; Redpoint Structures, structural engineer; Ferndale Ready Mix & Gravel, ready-mix supplier

After 25 years of service, the receiving dock for guests at the USS Arizona Memorial needed to be completely replaced.

The National Park Service in partnership with the U.S. Navy commissioned contractors to replace a weathered and worn floating dock area that had received millions of guests over its lifetime. Concrete was the obvious product of choice.

In the marine float environment, consistency in the weight of the overall design plays a key role in the function of a float. Floating concrete systems must provide ample strength and durability while maintaining a uniform weight and density to ensure balance, consistent freeboard and longevity to the entire float system.

Tolerances for mixes are unusually tight, and mix specifications are closely monitored to deter any variances from design. Unlike most projects, each and every load is measured to verify the unit weight, air volumes and mix consistency requirements are met.

In addition to the tight tolerances, a tertiary blend of cement, fly ash and silica fume were combined to densify the mix characteristics, and high-grade aggregates were acquired to produce a concrete mix resistant to chemical attack from the high humidity and saltwater environment. These aggregates contribute in providing key characteristics to the concrete properties, making it highly resistant to chemical attack, durable, long lasting and dependable.

The 75th anniversary of Pearl Harbor Day supplied a reason to fast-track the project. The contractor the needed materials onsite by midsummer 2016 in order to finish the project on time and within budget. The materials were produced in Washington in the spring, then shipped by barge in time for the deadline.

In late December, U.S. and Japanese dignitaries attended a ceremony to commemorate the events of Dec. 7, 1941. President Barack Obama and Japanese Prime Minister Shinzo Abe met to honor those killed on that fateful day when Japan attacked the U.S. This was the first time a prime minister from Japan had visited the USS Arizona Memorial.

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