Marine Borers Are Back

by Vahan Tanal, (M.ASCE), Vice President; Parsons Brinckerhoff, New York, NY,
Alex Matlin, (M.ASCE), Senior Professional Associate; Parsons Brinckerhoff, New York, NY,


Serial Information: Civil Engineering—ASCE, 1996, Vol. 66, Issue 10, Pg. 71-73


Document Type: Feature article

Abstract: Cleaning up the nation's harbors has brought a resurgence in marine borer activity. These organisms, mainly the teredo and the limnoria, eat at timber piers, undermining critical port structures. The first does not attack creosote treated wood, and the second one does. The teredo drill through piles and the limnoria nibble at the outside surfaces. In severe cases, they can cause a wood piling to lose an inch in diameter each year. Detection begins with inspection, typically with divers. Destructive methods include coring or slicing sections from piles. Non-destructive methods include ultrasonic scanning. Test boards are yet another detection approach. Untreated timber boards are placed underwater throughout a harbor and inspected annually for signs of infestation. Rehabilitation and prevention methods include encapsulation in epoxy or concrete jackets. Wrapping is another method, in which plastic wrapping suffocates borers by cutting off oxygen supply. Polyvinyl chloride and polyethylene are the two most common wrapping materials used. For new construction, underwater structures can be coated or lined to prevent borer penetration. Wood can also be treated with several preservatives, and many marine owners are now using non-wood materials such as plastics or concrete for these structures.

Subject Headings: Coastal structures | Wood piles | Inspection | Tests | Rehabilitation

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