"Mommy, where do bridges come from?" asked the Littlest Civil Engineer.
"Well," Mommy replied, "when a state-level transportation agency and two pieces of land separated by a body of water love each other very much, they ask the stork to bring them $6.3 billion dollars and 45,000 tons of Chinese steel. Then, if they eat all their vegetables, a dozen years later, a bridge is born."
But let's say Mommy is busy and doesn't feel like figuring out the best way to explain the tensile strength of iron rivets to a precociously nerdy toddler.
The folks over the Metropolitan Transportation Commission have come to the rescue with a time-lapse video from webcam company Earthcam. The film shows the last three years of progress on the construction of the new eastern span of the Bay Bridge.
The MTC explains:
The video shows the process step by step, including the installation of the steel deck pieces, the construction of a roadway connection to Yerba Buena Island, the erection of the tower piece by piece, the hanging of the catwalks from the top of the tower and the stringing of the main cable soon thereafter, the hanging of the vertical cables, and finally, the transferring of the bridge's load to the cable system -- all while a steady stream of cars zip along the old East Span just to the south of the construction zone.
The new span is scheduled to open on Labor Day 2013.
How will everyone celebrate its opening? By all accounts, the answer is, "in style."
"All we can say right now is that we're going to try to do something that harkens back to what was done originally for this bridge," Caltrans spokesman Bart Ney told ABC San Francisco. "There was a huge celebration for the opening of the original Bay Bridge. There were two presidents involved, a gigantic processional across the span, there was an amazing light show."
The $8 million light show portion of this celebration, which will include 25,000 programmable LED lights and is also part of the Bay Bridge's 75th anniversary, is scheduled to be unveiled in March.