A twofold collapse failure on a construction site for an extension of the Delhi Metro has officials investigating and rail opponents incensed. An elevated section of track came crashing down on July 12, killing six workers and injuring 20. One day later, three cranes trying to remove the launching girder had a “mechanical failure,” says Delhi Metro spokesman Anuj Dayal. Slide Show Photo: AP/Wideworld Launching girder was placing a concrete segment when pier cap failed beneath it. Photo: AP/Wideworld The design-build contract on the 20-km new corridor being built from Delhi’s central core to the southeast is held by Gammon
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.