Rod Under San Francisco Bay Bridge Tower Fails

Bay Bridge San Francisco (Frank Schulenburg / Flickr / CC / Cropped)
Frank Schulenburg / Flickr / CC / Cropped

A steel rod supporting the 525-foot tower atop the eastern span of the Bay Bridge has failed an integrity test, prompting fears that corrosion caused its failure and thus other rods may fail for the same reason, leaving the tower at risk from an earthquake.

Gareth Lacy, a spokesman for the state Transportation Agency, told The San Francisco Chronicle that a mechanical pull test had been performed on the rod on Wednesday, and the rod moved, a sign that it was defective, although Caltrans will not confirm the state of the rod until they remove a 25-foot-long fastener from its sleeve. The pull test was scheduled after ultrasonic tests revealed the rod was 6 inches shorter than the others.

Lisa Fulton, a metallurgical engineer and materials scientist at the Berkeley Research Company, told the Chronicle, “The thing clearly cracked. It means there’s little doubt that others are cracked–they just don’t know it. What are the odds this is the only one?”

Last week tests showed that three rod sleeves had increased chloride levels; the levels were 50 times more than last fall and could have been caused by saltwater. The bridge project’s oversight committee approved $400,000 for further testing. Caltrans stated, “Reaching a conclusion about the source of the water at this point would be clearly speculative,” adding that it is “monitoring to thoroughly evaluate the situation.” The agency concluded, “But in the end, what matters is drying the foundation and keeping it dry, which is exactly what we intend to do,” according to the Contra Costa Times.

In 2013, thirty-two similar steel rods failed on the bridge’s seismic-stabilizer structures from being soaked in rainwater, triggering work by Caltrans that cost $45 million.