Lead Designer of SF Bay Bridge's New Span Is Worried It's Already Corroding

Illustration for article titled Lead Designer of SF Bay Bridges New Span Is Worried Its Already Corroding

The single cable supporting the barely two-year-old eastern span of San Francisco’s Bay Bridge could be facing very real corrosion dangers, the lead designer of the $6.4 billion project warns.

In September 2013, San Francisco opened a beautiful, futuristic-looking new eastern span of its Bay Bridge, the city’s other major bridge besides the Golden Gate. But now, barely two years later, the San Francisco Chronicle reports that Marwan Nader, the main designer of the new Bay Bridge span, is concerned that rainwater is leaking into the structures that anchor the main cable, which could lead to corrosion of the cable itself.

According to minutes from a July meeting at the California Department of Transportation, the agency has acknowledged that storm water had been flowing into two of the cable’s anchoring structures, due to design problems. The Chronicle reports that corrosion concerns had been raised as early as May 2012, during construction.


The main cable is shielded by a steel jacket to protect it from weather. Two steel boxes anchor that cable onto the eastern end of the span. These anchorages, however, slightly expose some of the cable’s steel strands. This could eventually spell seriously bad news for the main cable, which is crucial in supporting suspension bridges like this one. CBS San Francisco reports that each anchorage is outfitted with a dehumidifier, leading the Department of Transportation to previously downplay corrosion risk. But those dehumidifiers aren’t enough to deal with a deluge of storm water, Nader argued at that July meeting.

The Bay Bridge’s eastern span ferries 270,000 vehicles between San Francisco and Oakland per day, and is the second-busiest bridge in America. This isn’t the first safety concern to be raised regarding the new eastern span. Earlier this summer, it was reported that integral steel rods holding up the span’s tower were previously thought to be damaged by corrosion, but were actually stripped during installation. The Department of Transportation had said no corrosion was good news—which no shit! Corrosion on a bridge is A Bad Thing. In light of these recent revelations, quality control concerns remain, including how the bridge would hold up in an earthquake.

The agency hasn’t said how it’ll deal with the anchorage corrosion risk yet.

[San Francisco Chronicle and CBS San Francisco/Associated Press]

Image credit: Getty

Contact the author at bryan@gizmodo.com, or follow him on Twitter.


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