A construction team led by Spanish contractor Sacyr Vallehermoso SA has won the mammoth Panama Canal expansion’s largest contract to date: the design-build job to build a third set of locks on the waterway’s Atlantic and Pacific openings. The locks contract is the heart of the $5.2-billion effort begun in September 2007 to expand the historic waterway. The winning team, which includes two U.S. engineering firms, proposes to construct the locks for $3.12 billion. The job had been estimated by owner Panama Canal Authority (ACP) to cost $3.48 billion, the quasi-government agency revealed on July 8. Photo: C.J. Schexnayder/ENR Firms
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.