In late July, four 1,200-ton, 165-ft-long steel segments were erected to become a tower for the $6-billion San Francisco-Oakland Bay Bridge’s self-anchored suspension span. Photo Courtesy Of Caltrans Steel tower legs are lifted into place for the San Francisco-Oakland Bay Bridge’s self-anchored suspension span. Under a $1.43-billion contract, the joint venture of American Bridge, Coraopolis, Pa., and Fluor Corp., Irving, Tex., used a strand-jack gantry positioned atop the erection tower to pull the segments off a barge, lift them straight up over the tower foundation, then lower them into place. The first four tower sections, fabricated by ZPMC in Shanghai,
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.