"This report was also reviewed and approved by our independent peer-review panel, composed of three members from the National Academy of Engineering," said Heminger.

The report concluded that welding process modifications mitigated cracking with successful results; quality-assurance, quality-control requirements were satisfied, and the problem cracks had been effectively eliminated. "We were fully aware of this issue," Heminger said. "It was a serious one, and we dealt with it."

As for Coe being reassigned because of speaking up about the welds, Tony Anziano, Caltrans project manager, said it wasn't a demotion but a "fresh start" for Coe. "He had gotten to the point where he could not function as a member of the team," said Anziano, adding that the contractor in China was "extraordinarily upset with some of the activities that occurred" after Coe complained of cracks in the deck welds.

In another case, Mike Morgan, a 15-year Caltrans veteran, testified that he tried for two and half years to get his superiors to investigate substandard concrete on a key bridge tower.

He cited a 2012 Sacramento Bee investigation that claimed the bridge contractor didn't tell Caltrans about a 19-ft section of concrete in a main tower that hadn't sufficiently hardened before testing. The story also revealed fabricated test results on the concrete structure by a Caltrans employee.

"After the falsifications were discovered, it quickly became apparent to me that the problem was being kept secret and either ignored or covered up," Morgan testified, adding there were other, "very serious problems that warranted a comprehensive investigation."

He said he took his findings through the supervisors in his "chain of command," including the Bureau of State Audits, the Association of Drilled Shaft Contractors, the DOT Office of Inspector General and two Caltrans directors.

One of these directors, Malcolm Dougherty, testified that, while he had a lot of respect for the witnesses, "they weren't the only people to work on this project. There were hundreds of people and many engineers on the job [with] differing opinions." He added that quality-assurance efforts, "in my opinion, exceeded the norms, not fell short."

Dougherty, who was appointed director in May 2012, said Caltrans should have acted more swiftly in investigating the issue with the tower concrete and the record falsification. He says that, as soon as he found out about it, he removed the person from state service and initiated a thorough evaluation of the issue.

Desaulnier pledged to hold additional hearings to examine Caltrans' apparent "deliberate and willful attempt to obfuscate what is happening."