Last month, 32 of the bolts snapped after workers tightened them. Experts suspect that they were weakened by standing in rainwater, the only obvious source of hydrogen during the five years they were in place on the span.
Such high-strength, galvanized bolts are banned on bridges by the American Association of State Highway Transportation Officials. Caltrans nonetheless ordered the 1,200-plus threaded rods, which technically are not classified as bolts and so do not fall under the ban.
Officials on the bridge project say that despite the months of work it will probably take to fix the damaged bolts, they remain confident the new span will be ready to open - and to host a party - on the Sunday and Monday of Labor Day weekend.
"Absolutely," said John Goodwin, a spokesman for the Metropolitan Transportation Commission, which is helping to oversee construction of the new east span. "There is no indication the opening of the bridge is going to be delayed in any way."
But Caltrans still hasn't inspected all 288 of the bolts nor devised a fix to secure two large seismic strengthening devices between the bridge deck and a support beam.