By Emmett Berg
SAN FRANCISCO (Reuters) - One of the several hundred high-strength steel rods anchoring the tower of the San Francisco Oakland Bay Bridge's new eastern span has broken, state officials said on Wednesday.
But California's transportation agency, Caltrans, said 99.7 percent of other rods examined passed a rigorous "pull" test, and that they should perform as designed in a major earthquake.
"More than 99 percent of the bolts we have already tested in the Bay Bridge tower foundation are not broken," said Dr. Brian Maroney, Caltrans' chief engineer overseeing construction of the bridge. "This is really good news and there are only a few more left to test."
The eastern span of the bridge, which opened in 2013, is considered a self-anchoring bridge notable for its single white tower, which the National Basketball Association's Golden State Warriors has adopted for their logo.
After more than 10 years of construction costing $6.4 billion, the new span replaced its predecessor, a multi-tower cantilever bridge built in 1936 that partly collapsed during the 6.9 magnitude Loma Prieta earthquake in 1989.
On Wednesday, Caltrans acknowledged the broken rod and assured the public the undergirding anchors of the span would perform adequately in the event of a major earthquake.
"The anchorage system at the bottom of the tower will function as designed," the agency said.
Incursion of water into concrete sleeves holding the 25 foot long steel rods may have caused corrosion and fracturing in the rod, and may still be weakening the bridge's defenses against an earthquake, the San Francisco Chronicle has reported.
The Caltrans statement did not address those reports.
(Reporting by Emmett Berg; Editing by Daniel Wallis and Sandra Maler)