A Caltrans official said Wednesday that he's confident a solution will be found soon to cope with the recent discovery of problems with 32 large bolts on the new eastern span of the Bay Bridge, which is slated to open on Labor Day weekend.
"We hope to reach some conclusions in the very near future and we don't expect a delay to the Bay Bridge opening," toll bridge program manager Tony Anziano told Metropolitan Transportation Commission members at their meeting Wednesday.
Caltrans ordered a total of 288 bolts, also known as rods, to connect the bridge deck to the 10-foot concrete cap that sits on top of the pier just east of the self-anchored suspension span tower.
Manufactured in Ohio, the bolts, which range from 9 to 17 feet in length and are 3 inches in diameter, are part of the seismic protection
features on the new span, which will replace the old span that partially collapsed in the 1989 Loma Prieta earthquake.
Anziano said the bolts were installed in 2008 but crews just started tightening a batch of 96 of them immediately below the bridge deck several years ago.
Inspections revealed a problem with 32 bolts that popped out several inches, a one-third failure rate that MTC Executive Director Steve
Heminger admitted is "very high."
The 192 remaining bolts, which are further below the deck on the same pier, haven't been tightened yet, MTC spokesman John Goodwin said.
Anziano said access to the batch of 96 bolts just below the deck is virtually impossible because they're in a confined and inaccessible area so he said a design solution that will keep them in place is necessary.
The most likely solution is "some type of exterior collar" that keeps them in place, he said.
Goodwin said if there are problems with the other 192 bolts it will be easier to replace them because they're further down and can be "jacked out."
Heminger said the MTC's initial assessment of the problem is that there is hydrogen in the metal in the bolts, which has made them brittle, and if that proves to be correct then "there clearly was a quality control failure" by the firm that manufactured the bolts.
He said if Caltrans has to order more bolts, it will do a more thorough job of inspecting them this time.
Anziano said it is not unusual for hydrogen embrittlement to occur during the process of manufacturing steel.