Crews recently topped out the $640-million Walter Reed National Military Medical Center in Bethesda, Md. The design-build project is being constructed on the site of the existing National Naval Medical Center as part of the Base Realignment and Closure Act of 2005 by a joint venture of Clark Construction Group, Bethesda, and Balfour Beatty Construction, Fairfax, Va. When completed, the building will feature a new 560,000-sq-ft ambulatory care clinic and a 165,000-sq-ft in-patient addition to the existing hospital. The team also is constructing an eight-story, 944-space patient parking garage, a 700-ft-long logistics tunnel and 450,000 sq ft of phased renovations
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.