San Francisco’s Bay Bridge is the dollar store version of the famed Golden Gate Bridge: it’s a bridge that transports cars, sure, but it’s less attractive and prone to breaking at inopportune times, like in the middle of earthquakes and occasionally just for no reason. Before the Bay Bridge closes down this summer for final touches on the new, safer eastern span, the bridge is getting gussied up by artist Leo Villareal, who is individually programming 25,000 white LED lights to generate an endless series of sparkling patterns across the structure.
This time-lapse video shows the erection of the suspension portion of the new Bay Bridge East Span, compressing the complex, labor-intensive, round-the-clock three-year effort into a fast-paced 2.5 minutes. The sun rises and sets more than 1,000 times as crews and equipment race against the clock and endure all types of weather to assemble the self-anchored suspension span (SAS), with its soaring tower and graceful canopy of cables. 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. Set to an original score, the time lapse provides a window into the intense activity involved in building this engineering masterpiece, which is set to open in the late summer of 2013.
High above the bay, on those orange catwalks that reach into the sky, ironworkers are making quick progress on the nearly mile-long cable that will eventually cradle the new Bay Bridge suspension span.
Within a week, they’ll finish compacting the 17,399 pencil-thick steel wires that have been dragged in bundles up and over the single-tower suspension bridge into one round cable with a diameter of about 31 inches. The cable will become about 8 inches thinner as it’s crunched into shape.
“This is another construction milestone,” said Bart Ney, Caltrans spokesman. “We’ve been able to stay on track to the most complicated part of the project - the load transfer. In fact, we’re ahead of schedule.”
Next, workers will place 114 steel bands around the main cable and, by the end of the summer, start hanging 200 smaller suspension cables that connect to the deck. As they install those cables, they’ll begin the critical work of shifting the load from the temporary trestle beneath the bridge deck to the main cable, adjusting the suspension cables to balance the load as they go.
SAN FRANCISCO — Venture deep inside the new skyway of the San Francisco-Oakland Bay Bridge, and it becomes clear that the bridge’s engineers have planned for the long term.
At intervals inside the elevated roadway’s box girders — which have the closed-in feel of a submarine, if a submarine were made of concrete — are anchor blocks, called deadmen, cast into the structure. They are meant to be used decades from now, perhaps in the next century, when in their old age the concrete girders will start to sag. By running cables from deadman to deadman and tightening them, workers will be able to restore the girders to their original alignment.
The deadmen are one sign that the new eastern span of the Bay Bridge, which includes the skyway and a unique suspension bridge, is meant to last at least 150 years after its expected opening in 2013. (The existing eastern bridge, which is still in use, will then be torn down.)
Every time I cross the Bay Bridge, I think back to the scenes from the 1989 quake when a section of the eastern span collapsed and cars were sliding down completely out of control. I am so ready for this replacement span to open.
Those steep orange catwalks that soar into the skies above the new Bay Bridge will soon come to life. This week, possibly as soon as Wednesday, construction crews will begin the laborious process of stringing the new main cable that will cradle the $6.3 billion single-tower suspension span expected to open late in 2013.
“This is one of the real high points in the construction of this bridge,” said Bart Ney, a Caltrans spokesman.
Workers have been testing the ski lift-like devices that sit atop the catwalks and will haul the 137 strands of steel wire from the east side of the suspension span up to the top of the 525-foot tower, loop it beneath the west end of the bridge deck, then drag it back up and over the tower and anchor it into the east end.
The first strand’s trip is expected to be painstakingly slow - two to three days, Ney estimated - to allow American Bridge construction crews to make sure everything goes smoothly. Once the kinks are worked out, Ney said, workers will be able to pull three or four strands a week, perhaps as many as two a day.
The new Bay Bridge east span towers over the old cantilever section. The completed cable, nearly a mile long, will be the world’s longest looped suspension cable. Photo: Noah Berger / Special to The Chronicle
(10-28) 14:43 PDT OAKLAND — With cheers, applause and a Christmas tree, the final stretch of the new Bay Bridge was lowered into place this morning, linking Oakland with Yerba Buena Island.
Crews hoisted the final small section of the bridge deck into place around 11 a.m., connecting the skyway with the suspension span.
Following ironworker tradition, a six-foot Christmas tree in a pot was placed on top of the roadway. For decades, ironworkers have attached a Christmas tree to the last piece of structural metal they install.
The segment weighs more than 1,000 tons and was lifted more than 150 feet into the air, according to Caltrans.
I just hope they get it done before “the big one” hits.
Oakland — For the first time since the design of the new east span of the Bay Bridge was selected in 1998, it no longer takes a healthy imagination or a look at artist renderings or models to visualize what it will look like.
On Monday night, catwalk lights were switched on at 7:45, giving the Bay Area a preview of the bridge’s after-dark appearance when it opens in 2013. A little more than a week ago, construction crews finished hanging orange catwalks that trace the path that the single-tower suspension span’s mile-long main cable will follow.
Construction of the single-tower suspension span - the most complicated and expensive part of the $6.3 billion bridge - is finally nearing the beginning of the end. On Sunday, the four final pieces of the span’s 28-piece deck arrived from Shanghai. Over the next few months, they’ll be hoisted into place, linking the deck of the suspension span with the white concrete skyway, completed in 2008.
The new Bay Bridge span
Nice to see this finally looking like a real bridge. I hope they are able to complete the span and get traffic onto it before the next big quake hits the Bay Area.