Six weeks ahead of schedule, contractors for the U.S. Army Corps of Engineers placed a 140-ton, steel vertical lift gate near the south end of an 1.8-mile-long storm surge barrier nearing completion in New Orleans. The placement marks the first closure of three openings on the surge barrier. It represents a significant milestone toward closing the barrier and having hurricane protections in place by the 2011 hurricane season. Manson Gulf LLC, Houma, La., used a 500-ton ringer crane for the March 24 installation of the gate where the Lake Borgne Inner Harbor Navigation Canal surge barrier crosses the Bayou Bienvenue
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.