SAN FRANCISCO (AP) — After numerous delays and cost overruns, pressure to complete the new $6.4 billion eastern span of the San Francisco-Oakland Bay Bridge led to pieces being created with cracked welds and other subpar work, government and private engineers told a state Senate commission on Friday.

The engineers did not conclude the new span is unsafe, but they told the state Senate's Transportation and Housing Committee that myriad construction mistakes could have been prevented. They said the mistakes could lead to costly future repairs.

"There was extreme pressure to not stop during the procedure because of a race for time," former California Department of Transportation bridge engineer Douglas Coe, a 25-year department veteran, told the committee.

Coe said he was moved to another department after raising concerns about cracks in welds to upper management.

The hearing followed a report released earlier in the week by the committee. The Associated Press covered the hearing from a live webcast.

Malcolm Dougherty, Caltrans' director, admitted mistakes were made during the long bridge project, but that the agency went above and beyond in quality control on welds and other areas of concern.

He said the opinions of Coe and others on the panel did not reflect the consensus of the hundreds of people, including many engineers, who worked on the bridge.

"The quality assurance on this project exceeded the norms, not the opposite," Dougherty said. "Any assertion that the bridge is not safe we would absolutely disagree with."

The report detailed accusations that Caltrans managers repeatedly dismissed concerns by quality-assurance experts about the integrity of seismic safety rods — important pieces that hold a shock-absorber-like piece called a "shear key" to the bridge deck.

Dozens of those rods cracked in March after being tightened, a failure that cost $25 million to repair.

Metallurgy experts, including James Merrill, an engineer who was hired by Caltrans to inspect the construction of key bridge pieces, said the defective seismic safety rods were made of a corrosion-prone steel that should never have been used.

Merrill testified that his report urged more testing on the rods, but that Caltrans approved them anyway.

Lisa Thomas, a metallurgist with Berkeley Research Co., said Caltrans chose the wrong steel for the rods, and said the agency had no experts on staff to help guide the decision.

"There was not metallurgical expertise on this project from start to finish," Thomas said.

Dougherty refuted that notion, saying the agency has metallurgists it consults.

The experts also expressed concerns about welds made in China that were disregarded by upper Caltrans management.

Merrill, who works for the contractor, MacTec Engineering, that was hired to oversee welds being done by the Chinese firm Shanghai Zhenhua Heavy Industry Co. Ltd, or ZPMC, said he raised concerns early on about the process.

"I recommended that, if state went forward with them, they could be doing so at great risk as a result of (a) lack of experience," Merrill testified.

Steve Heminger, a member of the Toll Bridge Program Oversight Committee, the bridge project's watchdog, said all concerns over the welds were taken seriously and investigated.

Heminger said a team of investigators was sent to China and created a report that led to changes in the way welds were handled.

According to Caltrans, efforts to reduce cracks were increased in 2009 after the concerns were brought forward and pieces were repaired before being installed.

"We were well aware of this issue, it was a serious and significant one, and we dealt with it," Heminger said.