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San Francisco-Oakland Bay Bridge Seismic Safety: East-Tie-In

Oakland, California

Market Sector




Services Provided

Design, Seismic Analysis and Design



In The News

Photo credit: Barrie Rokeach
Photo credit: Barrie Rokeach
Photo credit: Barrie Rokeach
Photo credit: Barrie Rokeach
Photo credit: Barrie Rokeach

T.Y. Lin International (TYLI), in a joint venture with Moffatt & Nichol (M&N), provided complete design services for the replacement of the 2.1-mile eastern spans of the Bay Bridge between San Francisco and Oakland. From conceptual and final design through construction support, TYLI has been involved in all phases of developing the world’s longest single-tower, self-anchored suspension bridge.

Project Highlights:

  • Challenging four-day schedule for design, detailing, fabrication and erection of nearly 5,000 tons of structural steel
  • Use of advanced BrIM modeling application to facilitate and accelerate the construction schedule

The East Tie-In structure is part of the South-South Detour, a project within the suite of San Francisco-Oakland Bay Bridge East Span seismic safety projects. The detour, a bypass structure temporarily supported by 200-foot steel towers, currently enables motorists to travel freely while construction takes place for the new Yerba Buena Island transition structure connecting the existing double deck configuration of the Yerba Buena Island tunnel to the new bridge.

Installing the 3,600-ton double-deck steel truss was performed 150 feet above ground and entailed a sequence in which workers removed an existing section of the Bay Bridge using a skid bent system that rolled the old 300-foot long truss span out of the way and rolled the replacement span in position, redirecting traffic onto the detour structure. The primary challenge of this critical transition was to minimize disruption to the 280,000 vehicles that cross the bridge daily by installing the tie-in structure within an amazing timeframe of four days over the 2009 Labor Day weekend. TYLI/M&N engineers designed the new roll-in truss such that after the roll-in, it matched the deck elevations of abutting structures within an inch. Their system contended with a narrow margin of error for responding to changes in field conditions. Traffic has now shifted to the temporary bypass structure to be used for a period of four years that began in 2009.

Accelerated Bridge Construction Commendation, 2012
National Steel Bridge Alliance (NSBA)
Golden State Award, 2011
American Council of Engineering Companies of California (ACEC-CA)
National Recognition Award, 2011
American Council of Engineering Companies (ACEC)
Bridge Project of the Year, 2010
American Society of Civil Engineers (ASCE) San Francisco Section
Award of Merit, Best of 2010
California Construction