Bay Bridge

Fact check: Sacramento Bee response to Caltrans request for retraction

The Sacramento Bee has rejected a request from Caltrans Director Malcolm Dougherty to retract its story raising questions about the structural integrity of a foundation of the new San Francisco-Oakland Bay Bridge. The story was first published online May 26 and in print May 27.

The Bee quoted Caltrans' assessment that the new bridge is safe in its original story and in the June 9 news story about the retraction request.

What follows is a fact check of what The Bee believes to be the most crucial points made by Caltrans in its retraction request. Bee editors worked with reporter Charles Piller to fact-check Caltrans complaints using information gathered from interviews with nine independent experts, thousands of Caltrans' own documents and Caltrans' response to written questions submitted by The Bee for its story.

Read the original story here.

A longer fact check reviewing all Caltrans' concerns point by point is available here.


Three tests of the concrete in the 13 bridge foundation piles - gamma-gamma logging, "slump" and cylinder breaks - proved the strength and safety of the Bay Bridge foundation piles.


Crosshole sonic testing found a 19-foot section of concrete in Pile 3 that was "not fully set" or was "very poor."

Caltrans and independent experts agree that the most likely cause of the problematic concrete was a failure to harden. Crosshole sonic testing uses sound waves to examine the interior section of a foundation pile. A second sonic test could have determined if the concrete eventually hardened properly, or was defective.

Instead, Caltrans used gamma-gamma logging, which tests sections near the edge of a pile with radiation. The contractor that conducted the sonic tests, Olson Engineering, and the manufacturer of the radiation device, Mount Sopris Instrument Co., agree that gamma-gamma tests cannot detect unset concrete.

"Slump" estimates the ability of wet concrete to flow smoothly, but does not indicate concrete strength after hardening.

Cylinder break tests measure the strength of small cylinders cast from a portion of the concrete used to create the pile. Caltrans records show that the cylinders tested were from a different load of concrete than those used in the suspect, 19-foot section.

None of these three tests conclusively determined whether the concrete strength in the problem section met the required 5,000 pounds per square inch standard necessary to withstand the most extreme earthquake.


The Bee failed to fully quote the suggested course of action by Olson Engineering after its sonic test of Pile 3 showed a large anomaly. Olson suggested either a repeat sonic test or a gamma-gamma test could be undertaken. Caltrans "complied with Olson's recommendation and conducted a (gamma-gamma logging) test," which proved that the concrete was sound.


It is true that in the story's first reference, The Bee should have more clearly explained the document in which Olson Engineering suggested further testing on Pile 3. The Bee posted the document online and in print told readers where to go online to see the document themselves, but did not quote the entire recommendation in the story. Instead, the story paraphrased Caltrans saying the original sonic report was not needed, nor was a follow-up necessary, because the gamma-gamma tests were sufficient. Readers would have better understood this issue if the document had been fully quoted in the story.

Olson declined to comment about its work on the bridge, so its reasons for suggesting the option of a gamma-gamma test remain unclear. It has stated in a company brochure about its work that gamma-gamma testing can't detect anomalies caused by unset concrete.

While Caltrans said it complied with the Olson recommendation, it appears that Caltrans could not have made a decision about which test would best re-examine the problem section because it was unaware of this issue.

This is how it played out: Olson found problems through the sonic test performed Jan. 9, 2007. Caltrans conducted a radiation test as part of its standard testing process on Jan. 12, 2007. The builder filled the testing pipes with grout on Jan. 24, 2007.

Olson issued its report noting the anomaly Feb. 8 2007, after the testing pipes were filled. To repeat a sonic test, the builder would have had to drill new test holes in the pile.

Last fall the bridge builder gave the sonic test document to Caltrans in response to a Bee story - nearly five years after the test was conducted. Caltrans said it did not have the report prior to that time.


The sonic test of Pile 3 detected a large section of concrete that was "very poor" or "not fully set." If the test had been conducted one day later, the concrete would have been confirmed as sound.


Caltrans might be correct. It also could be wrong. Since the sonic test was not repeated, it's unknown whether the concrete hardened to the specified strength. The Bee's story quoted one of the nation's leading concrete experts as saying it's unusual for one portion of a pile to take a day longer to harden than the rest of the pile.


Caltrans and the bridge builder followed agency rules and contract requirements for testing, which verified the bridge foundations as strong and reliable. Sonic tests are required only when radiation tests indicate a possible problem.


It is true that Caltrans did not require its builder to perform sonic testing in most cases. The Bee reported that fact in its story.

What Caltrans asserted in its retraction request is contradicted by its performance in the field. In the request it says, in underlined type: "Piles are not required to receive sonic tests unless a potential issue is identified by a GGL test." In practice on the bridge piles, however, records show sonic testing was routine, and preceded gamma-gamma testing in 11 of 12 cases. Caltrans and the bridge designer agreed on an unusual pile design that specially accommodated sonic testing, at a cost of slightly less reliable test results for the radiation testing.

No sonic test results can be found for Pile 8, raising questions about that pile in addition to the problem with Pile 3. The Bee reported Caltrans' response that it didn't require the sonic test. Yet all other piles received sonic testing.


Chipping of Pile 3 and Pile 8 - which received no sonic tests - was normal, and verified that both piles had hardened properly.


Chipping - using a power tool to remove defective concrete from the top of a pile - cannot prove that the pile has hardened to its required strength at the top or farther down.

"Hard" concrete reached after removing defective concrete might not meet pile design requirements. It includes no precision test, for example, to ensure that the pile can withstand more than 5,000 pounds per square inch of pressure, rather than, say, 2,500. Both are "hard" - but the lower figure would not meet the design requirement for holding up the bridge tower.

Pile 8 took six days to chip, about twice the time required for the other Bay Bridge piles. This point matters because, as reported in the story, Caltrans documents describe a pile with serious concrete problems on an offramp in San Francisco that similarly required an unusual amount of chipping. In that case, as with Pile 8, gamma-gamma tests showed no problems. The Bee story also described an Atascadero bridge which showed that chipping cannot reliably determine if a pile hardened properly.


The Bee did not give Caltrans the opportunity to respond fully to the scope of this story.


Caltrans Director Malcolm Dougherty would not meet with The Bee prior to publication to answer questions raised by documents and experts. Nor would Caltrans make engineers available to answer questions. Instead, the agency consented only to answer written questions, responded to via email by Tamie McGowen, assistant director for public affairs. Those questions asked for a response to concerns raised by key experts. The retraction request also ignores The Bee's attempts to get answers from Gov. Jerry Brown's office in the week prior to publication. Gov. Brown's office declined to respond.

In the past two weeks, through his press staff, Dougherty has twice canceled meetings with The Bee to discuss Caltrans concerns. The Bee has let Caltrans and the Governor's Office know they have a standing invitation to meet to discuss these issues.

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