page_title: Eastern span replacement of the San Francisco–Oakland Bay Bridge
section_title: SAS falsework
hierarchical_section_title: Eastern span replacement of the San Francisco–Oakland Bay Bridge / Design and construction / Main span / SAS falsework
caption_attribution_description: English: Falsework supports the deck sections of the eastern span replacement of the San Francisco-Oakland Bay Bridge
context_page_description: The eastern span replacement of the San Francisco–Oakland Bay Bridge was a construction project to replace a seismically unsound portion of the Bay Bridge with a new self-anchored suspension bridge and a pair of viaducts. The bridge is in the U.S. state of California and crosses the San Francisco Bay between Yerba Buena Island and Oakland. The span replacement took place between 2002 and 2013, and is the most expensive public works project in California history, with a final price tag of $6.5 billion, a 2,500% cost overrun from the original estimate of $250 million. Originally scheduled to open in 2007, several problems delayed the opening until September 2, 2013. With a width of 258.33 ft, comprising 10 general-purpose lanes, it is the world's widest bridge according to Guinness World Records.
  The Bay Bridge has two major sections: the western suspension spans and their approach structures between San Francisco and Yerba Buena Island and the structures between YBI and the eastern terminus in Oakland. The original eastern section was composed of a double balanced cantilever span, five through-truss spans, and a truss causeway.
context_section_description: The entire deck structure must be supported in precise alignment until:
  The end caps with anchors and turning and tensioning saddles are complete.
  The tower with its main cable saddle is complete.
  All deck segments are in place and joined.
  The internal tendons are placed and tensioned.
  The main cable is spun.
  All suspender cables are in place and adjusted for tension.
  The main cable tension is balanced on each side. (This is maintained as the suspender cables are tensioned.)
  The falsework to perform this task is a pair of substantial truss bridges, prefabricated in segments, with columns and span segments lifted into place by barge cranes. The trusses are supported on foundations consisting of or built atop deeply driven piles. Upon completion of the bridge, the entire falsework structure and all exposed underwater supports will be removed to make a safe channel for deep draft ships transiting to and from the Port of Oakland.
caption: Falsework parallel truss bridges temporarily supporting deck segment box structures
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