After wave action during 2012's Superstorm Sandy undermined Oswego harbor's 850 foot detached breakwall, the Corps of Engineers received 19 million dollars to restore the wall, which is crucial to the continued and increasingly important role of Oswego's Port Authority in the growth of Central New York's economy.
The Corps will deploy a true heavweight in Oswego. They'll use Dolos, 16-ton concrete structures, the largest they've ever used in a breakwater project.
Dolos work by dissipating the energy in waves, directing it sideways rather than trying to block it entirely. They interlock with one another to form a mesh, and over time, wave action tends to settle them more snugly together.
They will be placed on a bed of 20-ton Limestone, which is now arriving at the Port aboard hundreds of trucks and rail cars from quarries in Jamesville NY and Vermont.
Because there are gaps between and among Dolosse, they make excellent aquatic habitat for fish and other underwater creatures. Their sheer mass tends to collect and hold organic debris (logs and etc), which while decompossing help establish and maintain a nutrient rich environment.
Software developed in France will monitor the performance of the Limestone bed and precast structure in the face of Lake Ontario's waves and currents.
Durocher Marine is the lead contractor on the project, and Lakeland Concrete (Lima, NY) is building 950 Dolos, with the possibility of up to 100 more as the Corps and Contractor work to attain the design density along the targeted plot.
Dolosse were invented by South African engineer Eric Mowbray, who worked at the East London S.A harbor. After a severe storm in 1963, he set out to design a concrete block that could be "sprinkled on his existing breakwalls like children's jacks."
He and a fellow engineer came up with an "H" form with one side of the "H" rotated 90 degrees. This design, called a "Dolos", was so successful that today Dolosse (Dohl-awe-sah) are routinely used to protect beaches, create new breakwalls, and reinforce existing breakwaters everywhere in the world.
They are not, however, indestructible. They are formed from unreinforced concrete, and under extreme conditions can hammer each other and be ground into dust.
Sources: Concrete Products.com & Wikipedia.