CALTRANS San Francisco-Oakland Bay Bridge ConstructionLarge, defining, signature bridges are always a sight to behold but so too arethe construction efforts and innovation to successfully turn concept into reality.The newly released video at:http://www.fluor.com/about_fluor/Pages/videos.aspx?channel=4&videoid=314describes one such endeavor entering its final stages. The East Span of the SanFrancisco-Oakland Bay Bridge is the largest public infrastructure project inCalifornia’s history.I hope you enjoy the video and as always I appreciate your feedback! FACT SHEETCALTRANS San Francisco-Oakland Bay Bridge ConstructionClient: California Department of Transportation (CALTRANS)Location: San Francisco, CA, U.S.The American Bridge/Fluor Joint Venture (ABFJV) is constructing the $1.43-billion, 625-meter-longEast Span of the San Francisco-Oakland Bay Bridge. This first-ever, single-tower, self-anchoredsuspension (SAS) bridge is the largest public infrastructure project in California’s history.The project team has met major construction milestones, including erecting the world’s largest cablesaddle on top of the steel tower at 495 feet (151 meters) and installing the final, main cable strand onthe SAS bridge five weeks ahead of schedule.The ABFJV team designed a cable hauling system to install the strands from the deck anchorage on theeastside, over the tower saddle, around the west cap beam, back through the tower saddle, and finally
into the cable anchorage on the eastside. The cable erection equipment includes a primary strandhauling system or tramway and secondary hauling systems with transfer arms to float and install thestrands into the deviation saddles on the westside and through the tower saddle.Next the installed 137 strands will be compacted into a bundle and wrapped with zinc paste andstainless steel S-wire before being painted.Clients ChallengeThe eastern span of the Bay Bridge was damaged during the 1989 Loma Prieta earthquake when asection of the bridge’s upper deck collapsed onto the lower deck. While the damage to the bridge wasrelatively minor, its structural failure underscored the seismic vulnerability of this major transportationlink for the San Francisco area. The California Department of Transportation (Caltrans) specified thebridge withstand major seismic activity. Additionally, in an area known for its signature bridges, theaesthetics of the bridge also demanded construction excellence.The suspension cable system is a major construction challenge with a single cable anchored on one endof the bridge crossing over the top of the single tower, looping under the span’s opposite end, andcrossing back over the tower top to the other side. Additional challenges include construction of thefalsework supporting the new road deck and the single tower, followed by the transfer of the road decksto the suspension cable system and incorporation of elements that will provide seismic stability.
Our SolutionThe American Bridge/Fluor joint venture (ABFJV) began construction on the SAS portion of the bridge in2006. When finished in 2013, the SAS, together with the Skyway and Oakland Touchdown, will completethe East Span of the Bay Bridge. Initial construction activities included logistics planning and long-rangeprocurement. A 400-foot-long, 1,700-metric-ton-capacity shear leg crane barge was constructed to liftthe massive segments of the deck and tower. Bridge components are being fabricated in the UnitedStates, Europe, and Asia. A secondary office was established in Shanghai, People’s Republic of China, tooversee production of the main structural steel fabrication and supply.ABFJV erected a falsework structure to support the new road deck. Bridge components shipped via eightshipments, arriving every two months from China. Road deck segments are lifted from the barges ontothe falsework by the shear leg crane barge, with the road deck in-place after 28 lifts. The 160-meter tallsingle tower from which the bridge is suspended will complete concurrently. After installing the 800-mmdiameter main cable and suspender cables, the deck weight will be transferred from the temporaryfalsework to the main cable.ConclusionThe completion of the SAS Bridge will provide the San Francisco Bay area with not only a breathtakingbridge but also a sound structure that will withstand major seismic events and serve as an emergencylifeline route for disaster responses. ABFJV is providing new levels of innovation and an exactingprecision in work performance and construction quality to deliver a signature bridge that meets theserequirements.This project exemplifies the high-level coordination required between contractors, agencies, and thepublic to make sure all elements of this highly complex, multi-segmented, mega project come togetheras planned.