While the Golden Gate Bridge is the traditional symbol of our town, we think that other spans are no less beautiful. Reopened in 2013 following reconstruction, a project that faced years of delays and ultimately cost five times initial estimates, the San Francisco-Oakland Bay Bridge is a gorgeous piece of engineering. However, given continuing Bay Bridge safety concerns, our San Francisco bridge accident law firm is left wondering whether the bridge will ultimately be recalled as beautiful but tragic.
Cracks Found in Rods Used in Bay Bridge Foundation
As reported on SFGate.com, this week Caltrans formally acknowledged that tiny cracks found on rods used to secure the foundation of the Bay Bridge’s new tower may threaten to more than 400 other fasteners, particularly in an earthquake. Caltrans chief engineer for the bridge project, Brian Mahoney, added: “As an engineer, if I have these microcracks I have to assume they exist in every rod.”
Likewise, the agency admitted that a high-strength anchor rod, one of four in the tower, appears to have become brittle and snapped following exposure to water. In 2013, a similar problem caused 32 rods on seismic stabilizers to fail after being submerged, costing Caltrans $45 million just months before the span’s much-anticipated re-opening. On Tuesday, Mahoney told an oversight panel that experts found that a fastener that was removed for failure to hold up to testing suffered a “fast brittle facture.” Experts suggest this type of failure could only occur if the rod was exposed to hydrogen in water.
Potentially Corrosive Saltwater Found in Rod Sleeves
These reports are particularly concerning in light of revelations earlier this month that approximately one-quarter of the steel rods anchoring the tower are in sleeves that are penetrated by corrosive salt water. On June 5, the San Francisco Chronicle reported that 120 rod sleeves continually flood and half of those will fill with over 6 inches of water in only a matter of weeks, some filling with more than a foot of water merely days after being drained. Agency director Malcolm Dougherty who said that, while no bridge could be fully watertight, the saltwater intrusion is an issue because the foundation has “sensitivity to water getting to some components.” He elaborated, “We need to protect this — we need to come up with a solution.” The same article cited other potential concerns with the Bay Bridge including possible thread failures in a nut intended to secure one of the rods to a steel plate.
“Ominous” Results, “Unreliable” Components
An expert interviewed for this week’s article said that the discovery suggests the rods could break without a great deal of force, meaning they could snap even without the stress of an earthquake. “[T]hey are unreliable in the service loads they are under now.” Another expert called the results ominous and noted embrittlement can take years to occur. He suggested that the bridge might be safe today but wondered how safe it will be in years to come.
The bridge oversight panel declined to approve spending to clean and protect the rods, opting to weigh the options following further testing and additional expert recommendations. Per the June 6 article, the bridge project is already around $50 million over-budget and further testing could cost some $10 million.
Our Bridge Safety Law Firm
Bridge engineering accidents are incredibly serious whether the problem is a structural failure or a traffic accident caused by an unsafe design, such as the crashes that plagued the notorious S-curve that was part of a temporary fix to the old Bay Bridge span. When such accidents occur, all those involved from government agencies to private construction firms to at-fault drivers must be held accountable. We hope you never need us, but our Northern California bridge safety law firm is here to help if a bridge-related tragedy impacts you.
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(Image1 (daylight) by torbakhopper, Image2 (shadow w/ boat) by Edward Stojakovic)