The weekend closure of one of the nation's busiest bridge is likely to have to be extended. Inspectors have discovered some damage to the San Francisco Oakland Bay Bridge that could delay its reopening. The bridge that connects San Francisco and Oakland was closed Thursday night for a planned project. While inspecting the structure which partially collapsed during an earthquake 20 years ago, a crack was found in a chain-like steel link that helps support a section of the bridge. Officials say that flaw alone is enough to shut down the ten-line bridge that's crossed daily by hundreds of thousands of vehicles. The 73-year-old bridge was last inspected in 2007. So officials reason the crack material lines over the past two years. The structure is scheduled to reopen Tuesday morning following the holiday weekend. But now officials say they are not sure when the bridge will reopen. Two accommodate detour vehicles, commute train and ferry services have been expanded.