Caltrans: Crucial Bay Bridge Rods Pass Test

Save ArticleSave Article

Failed to save article

Please try again

The suspension tower for the Bay Bridge's new eastern span.  (Justin Sullivan/Getty Images)

So Caltrans is here with what it assures us is good news: More than 99 percent of the massive steel rods anchoring the tower on the new and forever-troubled eastern span of the Bay Bridge are intact, despite having been soaked in standing water for several years.

That's the result of several weeks of testing in which crews subjected more than 400 rods to a "pull test." Caltrans says the test involves "a powerful jacking device that grabs and yanks the rods with enormous force to verify integrity."

Why would Caltrans go to all that trouble on a bridge that's been open less than two years and is supposed to serve Bay Area travelers -- and withstand major earthquakes -- for the next 150 years?

Earlier inspections disclosed that all 424 rods in the tower foundation had been standing in water. That wasn't supposed to happen, and Caltrans has blamed contractors for improperly sealing the rods and leaving them unprotected. The agency is also still investigating the source of the water. It's possible that water from San Francisco Bay -- that would be extra-corrosive salt water -- is infiltrating the foundation and getting to the rods.

Caltrans has seen something like this on the bridge before. In early 2013, a set of steel rods identical to those in the tower foundation snapped when they were tensioned. Those rods were found to have been exposed to water for a long time and to have undergone chemical changes that made them brittle. Faced with a similar situation -- steel plus water plus tension -- Caltrans ordered its brutal-sounding pull test.


But before we get to the results, just a little bit more context on these rods and where they fit into the bridge's design.

There are 424 of them installed in the foundation of the eastern span's gleaming white 525-foot tower. The rods themselves are immense: about 26 feet long and threaded on each end, like bolts, and fitted with large nuts. Some 388 of the rods are 3 inches in diameter, and the remaining 36 are 4 inches in diameter. They're designed to prevent the tower from "rotating" -- tipping over, in layperson's language -- in the event of a major earthquake.

Bay Bridge Rods

Caltrans reported Wednesday that 14 of those anchor rods are inaccessible and can't be tested and that two others had been removed for lab analysis. The agency says it pull-tested the remaining 408 rods -- a process that reportedly cost $4 million -- and all but two appeared to be fine. That's more than 99 percent, Caltrans noted. And in case you want to be extra-impressed by what that looks like graphically, the agency produced a pie chart to show that.

But there's another way to interpret these glad tidings, and you can find it here: "Caltrans downplays latest Bay Bridge rod failure."

As the San Francisco Chronicle's Michael Cabanatuan notes in that story, two of the 408 rods that could be tested did not pass the test and are believed to have cracked or broken. And despite Caltrans assurances to the contrary -- Cabanatuan quotes Dan McElhinney, the agency official who now oversees the eastern span project, as saying the bridge looks "terrific" -- those two rods do raise questions about how much baby-sitting the bridge will need in the decades to come to make sure it's structurally sound.

Caltrans acknowledges that and says it will study the broken steel to find out why it failed. It's also promising to do more than that and says it's developing tests to determine how standing in water for so long will affect the long-term performance of the tower anchor rods.

The news several weeks ago about possible damage to those rods recently prompted Steve Heminger, the executive director of the Metropolitan Transportation Commission, to call the $6.4 billion eastern span "the project from hell."

He was more measured when appearing on KQED's "Forum" earlier this month. He emphasized that he believes the bridge is "perfectly safe" for day-to-day use. But he added the real concern is whether the bridge will survive a major earthquake intact -- the central goal in building the new span.

Heminger is on a three-member committee that has final say on the project. The panel is meeting Thursday evening to decide whether to approve funding for Caltrans to continue its investigation into the damaged foundation rods.

Last: If you're up for something of a seminar on the tower foundation and the anchor rods therein, here's a pretty cool Caltrans video of its chief engineer, Brian Maroney, walking the media through the issues: