A much-anticipated revision to the decades-old federal regulations on cranes and derricks is getting closer to firming up, but now one public-safety official in New York City is questioning the usefulness of the proposed standard. The city’s buildings commissioner, Robert LiMandri, says he is worried that New York’s own crane rules, imposed after what he calls an “abysmal” year of industry safety lapses, would be wiped out once the less stringent, national standards are put in place. The city has spent $4 million studying crane safety and is in the process of enacting more rules based on the report’s 41
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.