Systemic Coating Failure on a Nuclear Submarine Drydock, Evaluation and an Engineering Solution

The Delta Pier located at Naval Base Kitsap in Bangor, Washington, has served as the West Coast drydock for the U.S. Navy's Ohio Class submarines since its completion in 1979. A flame-sprayed thermoplastic coating was applied to the sheet piles of the pier in 2000, and that coating system quickly failed. In January 2007, the sheet piles of Delta Pier were inspected for corrosion damage. In concert with the inspection, the Navy requested that a replacement coating system be recommended. Many of the sheet piles on Delta Pier are located behind a relatively dense section of concrete piles that support concrete piers. The close proximity of the concrete piles so severely limits construction access that traditional coating systems, such as high-performance organic coating systems or thermal spray aluminum with a sealer, may be economically infeasible. This paper discusses several rehabilitation strategies, the construction constraints, and how these divergent factors were resolved to allow clear recommendations to be made. Additional strategies include covering the sheet pile tidal and splash zone areas with cast-in-place concrete or cladding with a copper nickel alloy.