Modular Floating Concrete Pier for the United States Navy

The United States (U.S.) Navy is developing a double-decked floating concrete pier as an alternative to the standard pile-supported berthing pier. This new generation pier can adjust to the changing needs of a Navy base, allowing quick replace¬ment of piers at capital cost compa¬rable to functionally equivalent fixed piers. Built of advanced materials and composed of uniform floating modules, the pier concept is known as the Modular Hybrid Pier (MHP). Four modules are assembled to form a full pier length of 396 meters. Pier modules can be added/subtracted and disassembled/reassembled as needed. The pier design follows principles for sustainable design as environ¬mental impact and life-cycle costs are considered. This leads to sub¬stantial economic benefits over a lifetime of 100 years, compared to traditional pier design. A test struc¬ture was built that reflects the char¬acteristics and complexity of a full-size pier. The test float was towed approximately 1900 km in open ocean from Seattle to San Diego where it is being subjected to a series of struc¬tural and functional tests.

Representing a significant capital investment for the U.S. Navy, most Navy pier and wharves were built between 1940 and 1960. With a typi¬cal design lifetime of 50 years, the current inventory imposes a substan¬tial maintenance, repair, and con¬struction burden. The cost for repair or replacement is often much greater than the original cost. Shutdown during repair or replacement often results in high collateral cost to Navy operations. As such, the Navy is investing heavily to develop an alter¬native pier with reduced life-cycle cost. After eight years, the Modular Hybrid Pier (MHP), a berthing pier based on a double-decked floating concrete structure, was developed.