California transportation officials hired a Chinese engineering firm to make repairs to the San Francisco-Oakland Bay Bridge, even though the company had never built a bridge before.

A breathtaking investigative report published by the Sacramento Bee has revealed the California Department of Transportation, otherwise known as Caltrans, selected Zhenhua Port Machinery to construct the famed bridge's new signature tower and roadway because the subcontractor promised to do the work faster and for $250 million less than the next lowest bidder.

As it turned out, the state agency paid the the Shanghai-based outfit added millions of dollars in incentives to compete the project in a timely manner, even as taxpayers were on the hook for hundreds of millions more to fix problems left by Zhenhua's's work, plus additional overruns that all but erased the expected savings and added to the bridge work's $6.4 billion in costs.

The Bee report included a timeline -- based based on its review of more than 100,000 pages of construction records and emails -- that showed the Chinese company's inexperience with U.S. construction rules became obvious early into the project, and that a number of Caltrans workers expressed concerns with quality control and oversight provided by the project's main contractor.

But, despite those revelations, state officials apparently opted to approve welding work that did not meet building codes that will now likely need extensive, and expensive, maintenance to correct, the Bee said.

Brian Maroney, the chief engineer who oversaw the project, reportedly defended Caltrans' decision to go forward with Zhenhua's bid by suggesting the company had produced excellent results and left state officials with the sense it would be extra alert to any potential problems.

The newspaper concluded hiring an inexperienced company located so far away from the San Francisco area led to unnecessary travel costs that included more than $300,000 spent by a state agency chief executive who traveled at least 64 times to Shanghai and stayed in a top-rated Marriott hotel for $470 a night.

Caltrans said in a written statement that the executive's accommodations were in fact reasonable and comparable to rates at other western hotels, the Bee reported.

Meanwhile, two engineers who worked on the project -- one for Caltrans and the other employed by a contractor -- testified during a California Senate committee hearing in January that they were taken off the project and reassigned after they voiced concerns about Zhenhua's work.

Both the engineers told lawmakers that even though they don't think the new bridge span that opened Labor Day is unsafe, they suspect the multitude of mistakes made during the new construction could cause expensive repairs in the future.