The new eastern span of the Bay Bridge will not open as scheduled on Labor Day because it will take contractors until at least December to repair cracks in seismic safety bolts, the Toll Bridge Program Oversight Committee announced Monday.
A new opening date for the $6.4 billion crossing will be decided after the retrofit of the failed bolts is completed, which is estimated to take until at least Dec. 10, the committee said in a report.
It will take that long to make and install a steel saddle to perform the same function as the failed bolts, Bay Area Toll Authority executive director Steve Heminger said. It is unclear how long it will take to make the saddle, but installation will take up to two months, he said.
“You might look at it as, our belt broke and we are putting on some suspenders,” said Heminger, chairman of the three-member oversight committee. “We are sorry, we are very sorry for this delay. ... We will be opening a safe new bridge for [commuters] as quickly as we are able to do so.”
The delay will force Bay Area motorists to keep using the seismically unsafe existing span well into the 25th year since a section of its upper deck collapsed during the 1989 Loma Prieta earthquake, killing one motorist and closing the bridge for more than a month.
The delay also will create complications because of worsening fall weather and because transportation officials had counted on a three-day Labor Day weekend to finish their work. Engineers will need to shut down the existing bridge for four days as they finish the new span.
However, engineers’ review of other bolts throughout the structure have not found further problems, easing concerns that they also could have become brittle from exposure to hydrogen. The other bolts have been in place and under tension for three months to four years without failing, Heminger said.
“We do not believe there is any further danger,” he told reporters after briefing four state senators in Sacramento.
“They feel confident there should be no other last-minute surprises,” Sen. Mark Leno, D-San Francisco, said after the briefing.
However, there is a longer term danger from what is known as “stress corrosion,” Heminger said. Engineers can deal with that after the bridge opens to traffic, he said.
Exposure to hydrogen was the root cause for why 32 seismic safety bolts became brittle and cracked after they were tightened in March, according to the report.
Monday’s report indicates that officials overseeing the project altered the original plan for treating the high-strength steel rods on the span. Initial bridge specifications required the rods to be mechanically galvanized.