More Problems for San Francisco's New Bay Bridge Span

At least 30 rods on the under-construction new span of the San Francisco-Oakland Bay Bridge have snapped after being tightened, the San Francisco Chronicle reports. The steel rods have been in place since 2008, and were tightened in the first few weeks of March as part of the construction process. Officials said one-third of the 96 rods that were tightened had snapped.

The snapped rods were likely caused by hydrogen embrittlement, when steel is exposed to hydrogen and causes it to fracture, officials said at a briefing this morning. Caltrans is now evaluating whether it will need to replace all 288 rods before the new bridge span opens around Labor Day. The catch with these 96 tightened rods, however, is that they are not accessible to repair, so officials are now looking into design workarounds that would serve the same purpose of the rods.