Metropolitan Transportation Commission officials said today that they’re troubled by the discovery of problems with 32 large bolts on the new eastern span of the Bay Bridge but they’re still hopeful the bridge will open on schedule in September.
Referring to other problems that have affected the lengthy construction process for building the new $6.4 billion span, MTC Executive Director Steve Heminger said, “We have surmounted far greater engineering challenges than this one and we’re confident that we’ll get through this one as well.”
Toll bridge program manager Tony Anziano told MTC board members at their meeting today that that 32 bolts ranging from 9 to 17 feet in length have popped out several inches since they were tightened several weeks ago.
That represents about one-third of the bolts in that spot, he said. They are located near where the new span’s self-anchored suspension span meets its skyway, Anziano said.
There are a total of 288 anchoring bolts on the new span, and at this point the bridge contractor and Caltrans are trying to determine if all of the bolts will have to be replaced, Anziano said.
Heminger said the MTC’s initial assessment 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, “A failure rate of one-third is very high” and that 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.
Anziano said he is confident that the problem can be fixed in time for the bridge to open on schedule over the Labor Day weekend but he said he wants to assure the public that the span won’t be opened until multiple inspections are done to make sure it is safe.
“We will make sure there is a proper and safe solution before we declare the bridge to be seismically safe,” he said.
Jeff Shuttleworth, Bay City News