Smarting from a second emergency closure of the Oakland-San Francisco Bay Bridge in two months, the California Dept. of Transportation is exploring long-term repairs for a cracked eyebeam until the crossing’s $6.3-billion modernization is completed in 2013. Caltrans engineers are considering replacing part or all of the truss system that has a cracked eyebeam, discovered by inspectors on the 73-year-old cantilevered eastern span during a Labor Day closure. Rancho Cordova, Calif.-based C.C. Myers Inc. was installing a 288-ft detour ramp as part of the reconstruction when inspectors found the 1½ in. crack in a 2-in.-thick, chain-like steel beam. The cracked
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.