The Panama Canal Authority has opened the bidding process for the last of four dry-excavation contracts for the waterway’s third-lane expansion. The dry excavation is needed to create a 6.7-km link between the existing navigational channel at the entrance to the Gaillard Cut, the canal’s narrowest stretch, as well as the new set of locks yet to be constructed. Last month, that $3.1-billion contract was won by an international team of contractors and design firms, Grupo Unidos por el Canal, led by Spanish contractor Sacyr Vallehermoso S.A. The upcoming excavation contract represents more than half the total works needed for
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.