Northern California Bay Bridge's broken rods being investigated Transportation officials are investigating why nearly three dozen threaded steel rods on the new eastern span of the San Francisco-Oakland Bay Bridge snapped when workers tightened the fittings. The Contra Costa Times reports the rods - up to 16 feet long and as thick as a man's thigh - connect the bridge deck to the concrete cap that sits on top of the massive pier just east of the bridge tower. According to a spokesperson for the Metropolitan Transportation Commission, at least 30 of the 288 bolts have snapped, reports CBS affiliate KOVR in San Francisco. Caltrans officials are expected to brief the Metropolitan Transportation Commission on the problem Wednesday. The commission is overseeing the new $6.4 billion span construction with the state. A commission spokesman has told media outlets the broken rods are not considered a structural problem and they are not expected to delay the scheduled Labor Day weekend opening. Randy Rentschler of the MTC told KOVR the problem shouldn't cause alarm, adding: "The bridge itself is well, well, way overdesigned. And this is a seismic element that is important, but Caltrans is confident that they have a design option to design around this. Engineers said the snapped bolts may be due to hydrogen found in the metal, which made the steel bolts brittle. The bolts were made in the United States.