New Bay Bridge Span Leaking

WEDNESDAY, FEBRUARY 19, 2014


Hundreds of leaks have sprouted in a supposedly watertight part of the San Francisco-Oakland Bay Bridge's new span, and state transportation officials are trying to determine why.

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, the San Francisco Chronicle reported.

California Department of Transportation (Caltrans) officials have said that while the amount of water is minimal, they just don't know where it's coming from. 

"It's a drip every once in a while. There are no locations where it's running," Rick Land, Caltrans' chief deputy director, told reporters during a news conference Feb. 10.  

Caltrans maintains that the bridge is safe, and that such issues were to be expected in the first few years of service. But if the leaks aren't dealt with now, there is concern that they could lead to corrosion. 

'Aggressively Investigating'

Caltrans has not found all of the areas where water is getting in, but Land said that engineers believe the rain may be flowing along electrical conduits and seeping into bolts securing guardrails.

On Tuesday (Feb. 18), Caltrans spokesperson Andrew Gordon told PaintSquare News that engineers and inspectors were still assessing the situation, and that an update could come later in the week. 

"It's something that we're taking seriously, but we're aggressively investigating it and we're confident that we'll solve it," Gordon told reporters, SFExaminer.com reported

"We don't want this to continue for the life of the bridge," Gordon said.

Wind, Caulking Eyed

Caltrans also said that strong winds were possibly blowing water sideways, preventing it from traveling through rain collection and drainage systems built into the bridge. 

"We're exploring all possibilities of how it got in and all possible locations for where it has gotten in," Gordon said.  

The leaks add to a long list of issues the bridge has experienced, starting last March when 32 anchor rods, or bolts, were damaged when they popped loose days after crews tightened them. The anchor rods were originally installed in holes in the concrete caps in 2008, but these holes were left to fill with rainwater for five years before the bolts were tightened.

Caltrans engineers ordered tests on the bolts in 2008, but those tests were never done after contractor American Bridge/Fluor disputed whether they were required. In April 2013, Caltrans released hundreds of pages of documents that showed its inspectors found structural integrity issues with some of the bolts years ago.

'Water Will Always Find Its Way In'

If the bolts are the source of the leaks, Caltrans officials said the likely fix would be to caulk the bolts and tighten them. 

Holes in caulking have also been suspected, but Caltrans doubts this is the issue because the water would have to get past the caulking, an epoxy coating, and the roadbed. 

"You would need all three systems to fail to get the water in there. I just don't see it," Bill Casey, a Caltrans engineer, told the San Francisco Chronicle

Bay Bridge bolts

"It's something that we're taking seriously but we're aggressively investigating it and we're confident that we'll solve it," a Caltrans official told reporters.

Casey said that the first five years of the bridge's life are known as a "shakeout" period, during which unforeseen problems, such as the leaks, can be resolved. 

"You do the best you can, but water will always find its way in," Casey said. 

Others Voice Concerns

Lisa Thomas, a metallurgical and materials engineer for Berkeley Research Company, told the San Francisco Chronicle that the leaks could lead to corrosion. 

"That's a problem, a big problem," Thomas said. "They want it to last 150 years, but with water coming in, something is going to corrode until it's too thin and weak."

Construction of the $6.4 billion bridge, which opened Sept. 2, has been managed since 2005 by the Toll Bridge Program Oversight Committee, comprised of representatives from Caltrans, the California Transportation Committee, and the Bay Area Toll Authority.

Last fall, Thomas and Yun Chung, a retired Bechtel Corp. materials engineer, authored a damning 105-page report detailing concerns about the Toll Bridge Committee's analysis of engineering issues on the bridge's anchor rods. 

Several other reports about the bridge and its oversight have emerged since September, drawing the attention of the state's Senate Transportation and Housing Committee and its chair, Sen. Mark DeSaulnier (D-Concord).

DeSaulnier has led the committee through a series of informational hearings on improving megaprojects, lessons learned from the Bay Bridge project and, most recently, on reforming Caltrans.  

   

Tagged categories: Bridge/parking deck waterproofing; Bridges; Corrosion; Department of Transportation (DOT); Program/Project Management; Steel

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