Two groups have aligned to develop a nationally accredited exam for a construction professional called by many names: crane inspector, crane certifier, crane surveyor and so on. Not required by the federal government, such a credential is only mandatory in California, and recently, Washington state, which started enforcement this year. The states launched inspector tests after tower cranes collapsed in San Francisco in 1989 and Bellevue, Wash., in 2006. The Fairfax, Va.-based National Commission for the Certification of Crane Operators, which helped Washington develop its test, and the Vancouver-based Crane Certification Association of America�which administers a private exam to its
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.