An analysis from a team of California Department of Transportation experts, released Thursday after more than a year of preparation, confirmed data problems involving radiation-based tests of reinforced concrete foundations for nine bridges or other freeway structures, including the Benicia-Martinez Bridge.
Caltrans executives examined additional records for the structures and deemed all safe, despite falsifications or testing errors by agency employees that the agency deemed "consequential." Numerous other irregular tests were considered unimportant.
"The subject matter may be complicated, but the conclusion is simple," Caltrans Director Malcolm Dougherty wrote to members of the state Senate and Assembly transportation committees. "California's transportation infrastructure rests on dependable foundations."
The report, which was spurred by a Bee investigation, was one of several related developments about Caltrans testing and the new San Francisco-Oakland Bay Bridge this week.
State officials approved $100,000 for an independent review of the new Bay Bridge, to address concerns raised in a Bee investigation.
The Federal Highway Administration released a report critical of Caltrans for its testing lapses and for improperly removing steel beams from federally funded job sites.
The governor formally began a countdown clock for the opening of the new Bay Bridge on Sept. 3.
Caltrans officials ordered the 612-page report about the bridge data problems in late 2011 in response to Bee reports that identified problems in testing procedures, and testing and construction lapses involving the new eastern span of the Bay Bridge and other structures.
According to the report, due to gaps and still-unanswered questions about the data, not all concerns about the work of Caltrans' Foundation Testing Branch could be laid to rest.
The six-member research group, composed of engineers and other experts, were dubbed the "GamDat" team because the relevant data was collected using "gamma-gamma loggers," a type of radiation-based testing probe. The team found that procedures meant to calibrate and ensure the reliability of that instrument also had been falsified, but probably had no effect on any structures.
Irregular test data for portions of the new Bay Bridge tower foundation apparently caused by errors in technique by technicians who examined the structure were considered minor and irrelevant to the strength of that span.
Deficiencies in how Caltrans organized and archived its test data made file identification challenging, according to the report. Thousands of data files could not be located, in part because an archival computer server crashed, destroying all data. It had not been backed up. Duane Wiles, a technician who confessed to falsifying data, retained unrestricted access to data archives long after his fraud was discovered, according to Caltrans internal memos The Bee obtained.
Consequently, an unknown number of data problems might have gone undetected.
The GamDat team did not interview anyone associated with doctored data, and made no comment on possible motivations for such actions. The report recommended sweeping changes in how the agency conducts and manages such testing, including upgraded file management and archiving systems, and improved test procedures.
Dougherty wrote to legislators that Caltrans was already implementing improvements.
The report did not address concerns about separate sonic tests of the new Bay Bridge tower foundation, detailed in a Bee investigation last May.