Officials from the Toll Bridge Program Oversight Committee, which oversees construction of the new $6.3-billion San Francisco-Oakland Bay Bridge, will travel to Shanghai at the end of August to investigate recent delays in steel deliveries from the Zhenhua Port Machinery Co. The discovery in January of cracked welds in girders has slowed shipments. Caltrans spokesman Bart Ney says a major delivery of deck- work segments for the self-anchored suspension span’s tower will be two months late. Ney says the delay will not affect the bridge’s 2013 completion date, but further delays may threaten the schedule. Photo: Caltrans
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.