Corroded tendons were one of many problems that have plagued the new eastern span of the San Francisco-Oakland Bay Bridge since its inception.
Political battles over the span's appearance and financing, manufacturing delays and quality-control scandals have contributed to delays in a construction process more protracted than the war in Afghanistan. Cost projections ballooned fivefold from $1.3 billion in 1996 to today's $6.4 billion, making the new span the most expensive public works project in state history.
The Bay Bridge has faced a litany of questions about its structural integrity.
In 2005, allegations emerged about faulty welds in steel plates that connect the skyway foundations to piers that hold up the bridge sections. Federal officials and Caltrans experts ultimately deemed the claims unfounded.
Never miss a local story.
In 2009, a second welding issue involved claims of poor fabrication quality by the Chinese steelmaker hired to create giant sections of the suspension bridge that connects the skyway to Yerba Buena Island. Delays ensued amid complaints that U.S. jobs were lost to a foreign company that provided an inferior product. Caltrans experts investigated, concluding that the welds fell within the required quality range.
Also in 2009, a crack was found over Labor Day weekend in a steel bar connecting portions of a temporary bypass on the old Bay Bridge near Yerba Buena Island. A quick fix failed six weeks later, raining heavy steel parts onto the upper deck during the evening commute. No one was injured.
In 2011 and 2012, a Bee investigation of the deeply-buried, reinforced concrete foundation for the iconic suspension-span tower found testing and construction irregularities. The stories prompted firings of Caltrans employees, legislative hearings, and federal and state examinations of possible construction flaws. In its own review, Caltrans judged the foundation to be sound. The Legislative Analyst's Office, at the request of the state Senate Transportation and Housing Committee, is coordinating a separate review of the issue by other experts. The results of that probe are due by June 30.
In March, after inquiries from The Bee, Caltrans officials revealed that 32 massive bolts had broken. This left essential seismic safety equipment on the east pier of the suspension span unsecured. The agency later conceded that thousands of other parts were considered suspect. Some did not pass all quality assurance sampling tests before installation and others violated a Caltrans ban on the use of galvanized ultra-hard, high-strength parts. Caltrans said the broken bolts had been sitting in water that had collected in the pier, probably causing corrosion that contributed to the problem. The agency is working on an engineering fix, but said it could not guarantee that the bridge would open as projected on Sept. 3, 2013.
Earlier this month, The Bee reported defects in 20 welds, essential for seismic safety, in the base of the bridge tower. Caltrans said it was examining and fixing the flaws, but has so far refused to provide details.
Call The Bee's Charles Piller, (916) 321-1113. Follow him on Twitter @cpiller.