Two months after a 110-lb light fixture fell onto a roadway along Boston’s Big Dig highway project, Massachusetts Dept. of Transportation inspectors have found some corrosion in the 23,000 lighting fixtures that line the Central Artery tunnel. In the wake of the resignation of a highway administrator following a delay in notifying the public about the fixture, the agency’s operational procedures are under scrutiny. “I have acknowledged our failure to alert the public in a timely manner and the lapse in our internal communications, which we are currently working to address,” state transportation Secretary Jeffrey Mullan says. “We are continuing
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.