New Bay Bridge span's dirty secret: stains with a big bill East span problem to cost nearly $1 million to repair

A bridge crew repaints the SAS tower of the new eastern Bay Bridge span from hanging scaffolding in San Francisco, Calif. on Thursday, July 10, 2014. A bridge crew repaints the SAS tower of the new eastern Bay Bridge span from hanging scaffolding in San Francisco, Calif. on Thursday, July 10, 2014. Photo: Paul Chinn / The Chronicle Buy photo Photo: Paul Chinn / The Chronicle Image 1 of / 10 Caption Close New Bay Bridge span's dirty secret: stains with a big bill 1 / 10 Back to Gallery

Workers on the new Bay Bridge eastern span are removing thousands of tiny steel particles that became embedded in the white finish and created rust stains on the span's signature tower - part of a cleanup and repainting job that is expected to cost close to $1 million, officials say.

Bridge officials are in talks with the main contractor on the project, the joint venture American Bridge/Fluor, to determine who is responsible for the staining problem on what is supposed to be a gleaming-white tower. It appears that toll payers will have to bear about half the cost, a bridge official said Thursday.

For several weeks, crews have been hoisted on scaffolds up the 525-foot tower to wash off the embedded steel particles and make other repairs to the paint finish.

The particles were molten hot when they were kicked out during steel grinding while the bridge's tower pieces were being connected. Over time, the particles are rusting and turning orange.

Crews are using detergent to remove the steel bits and rust and repainting spots where they are unable to scrub away the orange hue. Other workers are repainting in spots where rust has formed because of scratches or other damage that happened as the bridge was being built.

Caltrans spokeswoman Brigetta Smith emphasized that there was no underlying problem with the paint.

American Bridge/Fluor says the root of the problem was Caltrans' decision to have the tower finish-painted in China, where it was fabricated, rather than priming it there and waiting until it was shipped to the Bay Area and assembled on site.

Painting it early created the risk of damage as the bridge was put together, American Bridge/Fluor argued to Caltrans, according to bridge officials.

Avoiding corrosion

Caltrans officials have said they opted to have the steel tower painted in China to ward off corrosion on the long ocean voyage to California. They say the problem isn't that the tower was painted in China, but that the contractor failed to take the simple measure of covering it with tarps while other manufacturing was going on.

After pieces of the span arrived at the bridge site, workers routinely ground steel components to make them fit together. That grinding sent thousands of molten bits of steel into the air, and some of that debris bonded to the paint. Crews have found the grindings on the tower, the sides of the deck and the span's cross beams.

Some grinding was done during work to modify the elevator in the tower, a job that continued after the bridge opened in September, said Andrew Fremier, deputy director of the Metropolitan Transportation Commission. The elevator originally stopped short of the top, but Caltrans ordered it extended to help with maintenance. The agency also decided to enlarge the size of the elevator windows.

Equal blame

Fremier said the state and contractor share about equally in the repair cost, which he said totals less than $1 million.

"Some of it is damage caused by contractor operations, and some of it is from additional work to the elevator and other change orders," Fremier said. "Some of it is from the traveling public," he said, noting that steel barriers hit by motorists since the bridge opened are being repainted.

Bernard Cuzzillo, a Berkeley mechanical engineer and expert in failure analysis, said stains from grinding debris have long been recognized as difficult to remedy. Once the particles cool, they're tough to remove.

"Anybody who works with architectural steel knows you can't just let the grinding slag fly anywhere, because you are going to have an aesthetic problem," he said.

"It lands while it is hot, then adheres to the paint and gets stuck on it," Cuzzillo said. "That's why it is hard to remove it. You can't just brush it off."

Typically, construction crews will protect surfaces with thick plastic or canvas, Cuzzillo said.

"It's a simple and well-known problem that's easily avoided," he said.

Smith, the Caltrans spokeswoman, said the agency decided against such measures during work on the elevator because of the danger the sheeting could come loose in high winds and fall on a passing car.

Other problems on the new tower developed where the structure was scratched during construction. Water can penetrate those scratches, creating what are known as rust blooms under the paint. The rust attacks the steel and can cause long-term damage.

Months-long work

To combat the problem, the paint and rust have to be removed to the bare steel before the surface is primed and painted again. The work is expected to continue until at least the end of the summer.

Fremier said that even after the current painting is done, the finish on the span is likely to be a maintenance headache.

"It is a white bridge - it does show dirt and grime," he said. "We want to put in some energy to make it look nice."