THURSDAY, OCTOBER 2, 2014
After spending millions on extensive testing, California officials have revealed a new round of corrosion issues plaguing the $6.4 billion San Francisco-Oakland Bay Bridge.
The Good: Testing has confirmed that more than 2,000 anchor rods that give the span its seismic stability are safe.
The Bad: Crews are now inspecting the 424 rods that hold the span in place after finding more than a dozen surrounded by water.
The Ugly: Corrosion and debris were discovered in a 2011 inspection, which senior transportation officials say they learned of only recently from an employee's computer.
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| Tom Paiva / BATA via BayBridgeInfo.org |
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The $6.4 billion San Francisco-Oakland Bay Bridge opened to traffic Sept. 2, 2013. |
The California Department of Transportation issued its final report on the anchor rod testing program and discussed the latest round of problems Tuesday (Sept. 30) at a meeting of the Toll Bridge Program Oversight Committee.
TBPOC, which has managed the bridge since 2005, is comprised of representatives from Caltrans, the California Transportation Committee, and the Bay Area Toll Authority.
Coatings Keeping Rods Safe
According to Caltrans, all of the remaining rods on the self-anchored suspension span exhibit hydrogen embrittlement thresholds higher than their pre-tension stress levels and are safe, "even under the worst-case scenario of exposure to salt water as long as the galvanized coatings remains intact."
Caltrans performed an unprecedented level of testing after one set of anchor rods sat in water for five years, only to fail when workers tightened them in place. Those 96 rods, which were initially fabricated and installed in 2008, connected the bridge's shear keys to one of its piers.
In March 2013, crews returned to pre-tension the rods only to discover a few days later that 32 of them had fractured.
With no easy way to access and replace the rods, a temporary solution was implemented to open the bridge on time; an alternative anchoring system was designed and installed in December 2013.
Supplemental Protections in Place
An initial metallurgical investigation found that the rods had failed as a result of environmentally induced hydrogen embrittlement—a problem that could have been avoided entirely if the rods had been protected from water, Caltrans concluded.
Although that particular set of rods isn't in service, and the other 2,000 rods were fabricated separately, their failure raised concerns about the long-term performance of the remaining rods on the span.
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| Caltrans |
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"This strikes me as a pretty big fish that got away," Steve Heminger, executive director of the Bay Area Toll Authority, said about a newly discovered 2011 inspection that showed debris surrounding the anchor rods. |
All of the rods fabricated after 2008 were "designed to have both primary corrosion protection (galvanization) and supplemental corrosion protection measures, such as dehumidification, paint sytem, or grout, which would prevent corrosion and further rule out any future possibility of hydrogen embrittlement," Caltrans said.
A 'Big Fish That Got Away'
In its report, Caltrans revealed that an inspector had performed a video inspection on the rods in August 2011 and found signs of corrosion. At the same time, the inspector visually examined the rods' sleeve holes and found standing water plus "objects such as cigarette butts, U-bolts and wood chips."
Tony Anziano, Caltrans' toll bridge program manager, said senior officials found out about the inspector's report just this year when evidence of the damage was found on an engineer's computer.
After the meeting, Steve Heminger, executive director of the Bay Area Toll Authority, told the San Francisco Chronicle that the information should have been documented.
"That information, at the very least, should have been presented to us when we were in the middle of a full-scale investigation," Heminger said.
"This strikes me as a pretty big fish that got away."
'Not Acceptable'
But now, a new issue is afoot.
Caltrans reported that water was recently discovered at the bottom of the tower where 424 rods anchor the span to its base. The rods, each about 25 feet long, are protected by metal sleeves filled with grout and covered with caulk caps that are supposed to keep them dry.
This isn't the first time the new span has had a water issue since opening to traffic Sept. 2, 2013. Earlier this year, a routine maintenance inspection revealed that rain water was dripping onto the road deck beneath a steel chamber that supports the Bay Bridge's suspension span, although the chamber is supposed to be watertight.
"I'm a problem solver," Heminger told the San Francisco Chronicle after the meeting. "This is another problem—I certainly wish we would stop finding problems to solve."
According to Caltrans engineer Bill Casey, water was found on 95 percent of the rods. In most instances, water sat an inch or two deep between the grout around the rods and the caulk caps. However, 17 rods were sitting in gallons of water, because they were not properly filled with grout.
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| Caltrans |
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Caltrans has discovered water at the bottom of the tower where 424 rods anchor the span to its base. The 25-foot rods are protected by metal sleeves filled with grout and covered with caulk caps that are supposed to keep them dry. |
"It's not acceptable, and we're going to fix it," said Brian Maroney, Caltrans' chief engineer on the project.
It's possible that the caulking failed when the rods were tightened, Maroney said.
Finding the Water Source
Caltrans is now testing the water for zinc and to figure out where it came from.
Maroney said the rod chamber had flooded at least twice during storms, but the water also may have seeped in from the bay.
If the water tests signal corrosion, replacing the rods would pose a similar problem to the 2008 issue because there is no room in the tower to remove them.
Caltrans is now testing all of the anchor rods and using dehumidifiers to dry the ones that were exposed to water.
Caltrans Reform
Also on Tuesday, Gov. Jerry Brown signed a reform measure by State Sen. Mark DeSaulnier (D-Concord) that will require Caltrans to develop the state's transportation plans in a more strategic and open manner.
Senate Bill 486, Department of Transportation: Goals and Performance Measures, requires Caltrans to prepare an Interregional Transportation Strategic Plan to provide concise policy guidance for managing the state's transportation system. The bill also requires Caltrans to consider public input when developing the plan.
Caltrans will also have to report quarterly capital and support expenditures for the State Highway Operation and Protection Program and deliver a plain-language performance report.
DeSaulnier, chairman of the Senate Transportation and Housing Committee, first introduced the bill in February 2013.
"We must regain the public's trust on how the state government spends their money on transportation projects," DeSaulnier said.
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| Caltrans |
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All of the rods fabricated after 2008 were "designed to have both primary corrosion protection (galvanization) and supplemental corrosion protection measures, such as dehumidification, paint sytem, or grout, which would prevent corrosion and further rule out any future possibility of hydrogen embrittlement," Caltrans said. |
"Reforms created by SB 486 will create greater transparency and more opportunities for public input during the transportation planning process. We face historic shortages in transportation funding, and the public deserves to know that Caltrans is spending money on projects in a strategic manner that prioritizes modern transportation needs."
Agency Not Keeping Pace
In October 2013, DeSaulnier announced that he would lead an investigation into the issues on the Bay Bridge project. He also announced a series of hearings to examine problems that impact all megaprojects and improvements that can be made by Caltrans management.
According to DeSaulnier's office, an external assessment of Caltrans found that the department had not kept pace with changes in transportation policy.
While SB 486 addresses some of the flaws found in the external review, the assessment also calls for reforms to modernize the department's mission, strengthen its performance, and help align the department with the state's policy goals.
Tagged categories: Bridges; Corrosion; Department of Transportation (DOT); Galvanized steel; Inspection; Performance testing; Program/Project Management; Retrofits
