SACRAMENTO -- A builder of the new Bay Bridge failed to disclose that a 19-foot section of concrete in the foundation of the span's signature tower had not hardened before it was tested. By keeping quiet about the problem, the builder prevented further examination or repair.

The Sacramento Bee found descriptions of the apparent defect in records provided by Caltrans last fall to reassure the public about the overall stability of the suspension segment of the bridge's eastern span. Experts said the problem, combined with other construction and testing lapses by the California Transportation Department and its contractors, raises new questions about the structural integrity of the bridge.

Kiewit-FCI-Manson, a joint venture, built the foundation as part of a $177 million contract. It did not provide the problematic 2007 test results until after a Bee investigation in November showed that a Caltrans employee skipped required test preparation for separate checks of the same foundation and fabricated results on other structures.

The agency plans to open the $6.5 billion structure, the costliest public-works project in state history, by Labor Day 2013 to an estimated 100 million drivers annually. Caltrans said the bridge is sound and can withstand any anticipated earthquake.

Other concerns

Beyond the large area of suspicious concrete in one of the reinforced underground foundation piles, a Bee examination of Caltrans records found numerous other problems with the piles and found gaps in essential data. Experts who reviewed concrete and engineering records for The Bee questioned the ability of the main tower foundation to resist an extreme earthquake -- the reason for building the new bridge.

Among the findings:

  • Two of 13 piles that rise out of the Bay to hold up the tower contain suspect and inadequately tested concrete. Sonic-wave tests revealed a 19-foot section of poor concrete in Pile 3, in a location subject to profound seismic forces. When tested, the concrete had not hardened to the required strength. It was not retested. For unclear reasons, Pile 8 either received no sonic test or builders could not locate the test report. Job site inspection diaries also show construction abnormalities in that pile.

  • Sonic test reports contained more than 20 errors. Among other slips, they misstated which piles were tested, test dates and pile measurements. Experts said the unusual volume of mistakes casts doubt on the reliability of testing for both the problem pile -- Pile 3 -- and others deemed free of defects.

  • Builders treated the piles with an additive meant to increase concrete strength, but known to cause soft or poor-quality concrete when overused -- one possible explanation for the 19-foot anomaly. Although batching computers should ensure mixing precision, records for a different pile show unexplained mixing errors by a concrete plant computer.

  • Caltrans and its experts said the bridge is safe. Many of their supporting assertions were contradicted by agency documents. For example, a Caltrans panel asked to review the work said sonic tests proved that the piles were of sound construction, despite the Pile 3 problem and the lack of testing for Pile 8. Panelists relied heavily on tests of what they called "full-scale" mock-ups. Those models actually were a small fraction of the bridge piles' size. Independent experts said the mock-ups offered invalid comparisons.

    Larry Olson, president of Olson Engineering, which conducted the sonic tests, declined to comment without permission from Kiewit Corp. Kiewit referred all questions to Caltrans.

    Olson Engineering detected the problem concrete in Pile 3 in 2007, calling it "a batch of concrete that has not fully set at the time of testing" or "a very poor area of concrete."

    "The most likely cause for the (19-foot) anomaly is concrete that didn't cure," or harden, said Les Chernauskas, general manager of Geosciences Testing and Research Inc., a Massachusetts company that specializes in sonic testing.

    Through a spokeswoman, Gov. Jerry Brown declined to answer questions about whether Caltrans has kept his office informed of ongoing concerns about the bridge.

    Caltrans spokeswoman Tamie McGowen responded in writing to Bee questions. "Substantial evidence," including tests of the small mock-ups and the other bridge piles, indicates that the abnormal concrete in Pile 3 eventually hardened properly, she wrote.

    "We are confident in the structural integrity of the main tower foundation and that the bridge will perform as designed to handle an extreme earthquake," McGowen said. A panel of engineering experts hired by the agency to re-evaluate the safety of the foundation concurred.

    Problem piles

    "The way that they conducted the testing program, and the results, do raise some serious issues with respect to the quality of the concrete," said a university professor and expert in deep foundation testing, who also reviewed the documents at The Bee's request. He spoke anonymously for fear of jeopardizing business relationships with contractors for Caltrans, among the nation's largest public-works funders.

    A chief concern, he said, involves the absence of sonic data for Pile 8 and the location of problem concrete in Pile 3, toward the top of the pile, "subject to the most significant loads during an earthquake."

    Kiewit began building foundations for the Benicia Bridge shortly before taking on the Bay Bridge project. Records show that Caltrans engineers recommended rejection of nearly all the Benicia piles built before awarding the Bay Bridge contract to the Kiewit joint venture. Those piles, almost one-third of the Benicia job, were deemed either too flawed for use without repair or required retesting due to construction errors.

    Soon after the Bay Bridge sonic testing, Kiewit-FCI-Manson provided Caltrans with results for six of the 13 piles.

    They showed only minor problems. It failed to deliver the other sonic reports, including one showing the huge anomaly.

    Caltrans did not request those tests, McGowen said, which technically were not required by the construction contract.

    Because the company declined to comment, its motives for withholding test data remain private. Substantial repairs on a giant pile can cost up to $1 million.

    Thomas W. Joo, a University of California, Davis law professor and contract authority, said that even if Kiewit and its partners had no contractual duty to report the sonic data, they could face legal liability for "straight-up bad faith."

    "If it's a matter of public safety, the calculus is different," he said. "The whole thing is colored by what's at stake."

    By providing findings for six piles, the builders could have "engendered a duty to disclose" more fully, Joo said. "Partial, misleading disclosure is a species of fraud."