The U.S. Army Corps of Engineers and its contractors are setting a record for achieving the fastest gain in consolidation and strength on earthen levees—a mere 60 to 90 days, compared with 10 to 11 years—by using an intricate design that layers a sand blanket, geotextile fabrics, rock and wick drains to evacuate moisture from marshy soils. “Something of this major import, of this scope, is rare, and we are using unique and unusual means to achieve those goals,” says Al Naomi, program manager, URS Corp., San Francisco. URS performed geotechnical design and developed plans and specifications for the levee
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.