Workers are making good progress dismantling and cleaning up the U.S. Energy Dept.’s Oak Ridge former nuclear-weapon factory complex in Tennessee, says a report released last week by site contractor Bechtel Jacobs. But the contractor and DOE acknowledge that some work at its massive K-25 building are behind schedule. Bechtel Jacobs says it removed a bridge structure connecting two sections of the 1.6-million-sq-ft building, which houses uranium-enrichment equipment dating back to the Manhattan Project era and was the world’s largest structure when erected. Cleanup work at the adjacent Oak Ridge National Laboratory, the Y-12 National Security Complex and other parts
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.