Cutting a 55-in.-dia. hole into concrete is hardly rocket science in construction, but when the hole is being cut into the concrete shell of a huge underground tank that has been storing highly radioactive plutonium waste for more than 60 years, that action could be the equivalent of a space-shuttle trip into the unknown. Photo Courtesy of WRPS Matt Landon, a project engineer for WRPS, the cleanup contractor at the Hanford nuclear-waste site in Washington state, measures the progress of a concrete cutting tool during a test on a simulated underground waste-tank dome. Photo Courtesy of WRPS Employees of WRPS
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.