2/26/2014 2:42:00 PM
NEWS BRIEFS
Bridge Officials “Encouraged” By Ongoing Bolt Test Results
Oakland Bay Bridge officials said they were encouraged by the latest testing results of massive steel rods used in the new eastern span of the structure, the San Francisco Chronicle reports.
“A test of galvanized steel rods like 32 that cracked on the span last year showed that they didn’t fail until they were stressed beyond their rated capacity,” according to the Chronicle. “About 2,200 similar rods and bolts are still on the span, performing various vital roles.”
In earlier testing, three samples failed at stresses “below their designated maximum capacity, but above the level at which they are in service on the bridge.”
“These tests are encouraging because these (latest rods) broke at much higher tension levels and in a much more corrosive environment than exists on the bridge,” stated bridge spokesman Andrew Gordon.
The results are part of a $10 million testing program initiated after 32 rods anchoring the roadway to earthquake safety structures cracked in March 20013 soon after being tightened.
Because some of the failed bolts were embedded in concrete, bridge officials were forced to order an elaborate $25 million retrofit to fix that portion of the $6.4 billion bridge expansion.
Hydrogen embrittlement was determined to be the cause of the failure. ©2013 GlobalFastenerNews.com
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