The San Francisco-Oakland Bay Bridge is six months older than the Golden Gate and is undergoing a long-term replacement. This weekend a new 7,000-ton steel section was dropped into place. Photos and a time-lapse video below.

While inspecting the bridge before adding the new section engineers founds a crack in part of the bridge, necessitating a last minute repair. This video shows the steady progress of upgrades and the building of a support structure for the new piece from April of this year until the bridge opened Yesterday.

Eventually, the entire current east span of the Bay Bridge will be torn down and replaced with a new section. Some of the old structure will end up in museums because of its historic significance, but the bridge itself is too much of an earthquake hazard to be retained.

Photo Credits: Royterp (top photo), all other photos
Special thanks to super intern Rose Annis for putting the video together!