bbtower.jpgAfter nearly 21 years of planning, cajoling and hand-wringing, the final segment of the new eastern span of the Bay Bridge began to take shape Wednesday in the waters off Yerba Buena Island.

Crews set to work at about 6:30 a.m. readying the tower leg for erection by slowly tipping it into a vertical position atop a barge floating near the base of a steel erection tower.

On the barge, a wheeled cart on rails guided the base of the tower section while the hoisting system atop the erection tower, located about 235 feet above the water, raised the top of the section.

Once vertical, the section was unbolted from the barge cart and gently lifted another 45 feet to pass over a crossbar and through a “window” in the erection tower.

Then, the hoisting system was able to slide horizontally atop the erection tower, ever so slowly moving the 1,200-ton section over the concrete foundation sticking out from the water’s surface.

The operation required extreme precision to ensure that the massive section hovers over just the right alignment so that crews can fit the section into the rod-like connection points sticking out from the foundation.

A lone worker stood atop a foundation for the existing bridge, taking measurements using a laser-assisted transit to ensure the tower section is where engineers want it to be, Ney said.

A project engineer with the bridge’s primary contractors, American Bridge Co. and Fluor Corp., said he was confident the piece would fit, “…After four painstaking years of planning and watching literally thousands of fabricated pieces come skillfully together into the massive tower elements of this one-of-a-kind bridge.”

Over the next three weeks, crews will repeat today’s process with the remaining three legs of the first tower lift.

Come October, when the second shipment of tower sections is expected to arrive from Shanghai, crews will repeat the process at a slightly higher elevation.

The tower crane and gantry system will be stacked taller to accommodate the rising tower legs, which will eventually protrude 525 feet above the foundations.

The bridge is expected to open to traffic in late 2013, nearly 21 years after the magnitude 6.9 Loma Prieta earthquake shook the Bay Area, revealing a fatal weakness in the existing Bay Bridge.

“I want to pledge to you our best efforts in working with you and your stakeholders to complete the new bridge by 2013 as safely and as quickly as we can,” said project engineer Mike Flowers, who paused during the ceremony to recognize the accomplishments of the thousands behind the bridge.

Motorists coasting along the span will drive underneath a single 32-inch diameter cable once the bridge is complete.

Unlike the region’s other suspension bridges, the self-anchored suspension Bay Bridge has a cable that will crisscross above the roadway as it threads a path up and over the single tower, from the east end of the span to the west end and back.

“It frames the bay in a new way,” Caltrans spokesman Bart Ney said.

By 12:45 p.m., state and local leaders had gathered under a tent on nearby Treasure Island against a cloudless blue sky to celebrate the project’s historic benchmark.

Among the speakers were Oakland Mayor Ron Dellums and San Francisco Mayor Gavin Newsom, who struck a serious tone by reminding the audience that despite the celebrations, completion of the project is still a few years away.

Newsom said that as a city supervisor he “thought this would never happen” given clashes between then mayors of Oakland and San Francisco Jerry Brown and Willie Brown, respectively.

“We are reaching our goals, we are working collaboratively together,” Newsom said. “The bureaucracy is moving, unions are working, people are out here, and real things are taking shape.”

Newsom also took a moment to flaunt a baseball cap embroidered with the new logo for the Golden State Warriors, which was redesigned to feature a depiction of the Bay Bridge’s single tower.

Dellums, representing the city at the eastern end of the bridge, showered praise on Caltrans and all parties involved for building a “world-class, landmark bridge” and shared a personal account that he said gives him the authority to speak about the bride’s origins.

He said pedestrians could pay a nickel or a dime to walk the span when it opened in 1936, and that’s just what his parents did as they carried Dellums as a baby in their arms across the Bay Bridge.

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