PHOTOS: Crack in structure may delay Bay Bridge reopening
By STEVEN LUO
Beat Staff Writer
Caltrans is expected to announce Sunday afternoon whether a structural flaw in the eastern span of the Bay Bridge will prevent the bridge from being reopened to traffic on Tuesday morning as scheduled.
Inspectors discovered “a significant crack” in an eyebar up in the superstructure of the cantilever section of the bridge Saturday, said Caltrans spokesperson Bart Ney at a news conference Saturday night.
The crack extends about halfway through the two-inch thick steel, and is said to be visible with the naked eye from the bridge deck, 120 feet below.
Emergency repairs have begun, but it is unclear whether they will be completed in time for the scheduled reopening of the bridge at 5 a.m. Tuesday morning, and Ney says it will take “a monumental effort” to do so.
A 10-person crew will weld a steel “saddle” over the cracked eye, taking the stress off the part.
Parts for the repair were fabricated Saturday night in Arizona and flown in Sunday afternoon on a chartered DC-9 jet to Oakland International Airport, from where they were escorted to the bridge by CHP officers.
In all, 18,000 pounds of steel will be used in the repair.
Ney told reporters Sunday morning that there is no timeline for when the repairs to the cracked beam will be completed. He said that drivers were not in danger because of the defect and that an inspection of the area two years ago showed no fracture.
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- MORE: Commute alternatives to get around the closure
The cracked beam is not in the new section of the bridge which is being moved into place over the weekend, and was not caused by this weekend’s effort to replace part of the span, Caltrans says.
The damage is significant enough that the bridge would have had to be closed in any event.
The crack was caught during an inspection scheduled to take advantage of the lack of traffic during the bridge closure. A similar inspection occurred when the Bay Bridge was closed over Labor Day weekend in 2007.
In a steel truss cantilever bridge like the eastern span of the Bay Bridge, the steel beams which make up the superstructure form two lever arms anchored at the ends of the bridge, which support the weight of a span in the middle.
When a beam fails, the load is redistributed onto other parts of the structure, resulting in a significantly weaker bridge. As long as the remaining good components can bear the strain, though, the structure will not collapse.
Caltrans believes that the cracked part would not have caused the bridge to collapse if it had gone undetected.
E-mail Steven Luo at californiabeat@gmail.com. Join the California Beat on Facebook, and get breaking news headlines, story alerts and previews when you follow us on Twitter.
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Although I’m not an expert in bridge inspections, I am certified to inspect metallic/mechanical structures. With out reading the repair scope for this “linear indication – not crack”, as we all know only a metalurgist can call an indication a “Crack”, I see a lot of questions not being asked from the public.
1.) If the crack is being “saddled”, aka scab patched, did they grind out the crack…to keep from propergating beyond the “saddle” aka temporary repair?
2.) If the crack can truly be seen from +100ft., and was not observed during an inspection 2yrs. prior, what caused such an adverse change? Industrial practices prove that stress cracks (which in my opinion this is) form over time and the amount of posed stress. What type of inspection was performed to ensure the crack was not through wall? So, with this being a stress crack, please have the “Inspectors” (not public spokesperson) answer question number 1, and answer me this: What non-destructive testing was performed, after observing known cracks, on all other load/stress bearing joints?