In-Situ Subsurface Coating of Corroded Steel Sheet Pile Structures: Final Report on Project F08-AR06
ERDC-CERL CHAMPAIGN United States
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The Department of Defense DoD spends over 100 million annually maintaining and repairing waterfront infrastructure, including corroded steel sheet pile structures located in warm, salt-water immersion and areas susceptible to accelerated low-water corrosion. Once designed as temporary structures, many now support permanent requirements and must be repaired in place. Conventional underwater repairand coating operations are accomplished by specialized divers at very high cost. This project investigated a cost-saving emerging technology called a limpet cofferdam, which is readily positioned below the waterline to provide workshop-like conditions for repair technicians, and is rapidly movable along submerged sheet pile structures. Also demonstrated was a highly durable, single-coat amine epoxy system that fully cures in immersion. Limpet deployment and dewatering was completed in 30 minutes or less, and leaks into the workspace through damaged sheet pile were sealed in 530 minutes, depending on perforation size and other variables. The coating was found to be readily sprayable with only minimal pinholing, and fully cured under water. Literature indicates that this coating can be expected to have a 25-30 year service life. The calculated return on investment for these technologies is 14.70, with higher potential return when planning includes the recommended site-assessment methods.
- Properties of Metals and Alloys