NEW YORK The California Department of Transportation (Caltrans) is investigating the cause of damage to 32 steel rods on the San Francisco-Oakland Bay Bridge that had been supplied by Painesville, Ohio-based Dyson Corp.
Construction workers tensioning 96 steel rods for bridge contractors American Bridge Co., Coraopolis, Pa., and Fluor Corp., Irving, Texas, in early March found evidence of fracturing on one-third of the rods.
Dyson was contracted for 288 threaded steel rods ranging in length from 9 to 17 feet for the bridge, a spokesman for San Franciscos Metropolitan Transportation Commission (MTC) told AMM. Ninety-six rods were manufactured and installed in 2008, of which 32 showed evidence of fracturing. The remaining 192 rods were installed in 2010, he said.
"It has not yet been determined whether the presence of excess hydrogen (that may have caused the damage) is due to something in the manufacturing process or something in the galvanizing process," the spokesman told AMM.
Caltrans is currently investigating Dysons possible culpability, and the MTC spokesman said authorities dont know yet if the company had made the product from start to finish.
"It hasnt been determined whether galvanizing was done by Dyson itself or a subcontractor," he said. Dyson Corp. and Caltrans didnt return calls for comment.
The fasteners were supplied for the bridges $6.4-billion reconstruction project on its eastern span, which started in 2002, according to the San Francisco-Oakland Bay Bridge website.