Make-or-break Tests For Bay Bridge Opening

Make-or-break tests for Bay Bridge opening Steel bolts on the new Bay Bridge eastern span made by the same company that supplied 32 rods that failed when they were tightened must undergo rigorous testing to determine if they are also at risk of cracking, Caltrans officials said Wednesday. The outcome of those tests, expected within two weeks, will determine whether the $6.4 billion span will open to traffic the day after Labor Day as scheduled, Caltrans Director Malcolm Dougherty said after briefing Bay Area transportation officials about the broken-bolt investigation at a meeting in Oakland. The bolts were covered by the bridge roadways soon after being installed and are no longer accessible, so Caltrans is considering adding a metal saddle or collar around the seismic-stability structures to do the bolts' job. The 2008 bolts are believed to have been weakened by hydrogen that was able to attack because the steel was near the maximum hardness level allowed under industry standards. Caltrans officials say they think the bolts delivered by Dyson in 2010 were not as hard and may be better able to resist hydrogen, which is abundant in the marine air. The American Society for Testing and Materials, an industry group that developed the metallurgical standard for the type of bolts installed in 2008 and 2010, has warned that "hydrogen-stress cracking or stress cracking corrosion may occur" if the rods are galvanized.