Rebuilding the Bay Bridge

The $3.2 Billion Project Passes 35-Percent Completion Mark

Most of the work thus far has focused on the $1 billion skyway, a 1.2-mi. stretch that features a side-by-side deck gradually rising up from the Oakland side of San Francisco Bay to Yerba Buena Island. Caltrans said the new bridge should open in late 2009 or early 2010.

By Thomas York

Construction of California's costliest public works project ever-the $3.2 billion East Span of the San Francisco-Oakland Bay Bridge-recently passed the 35-percent completion milepost.

Dan McElhinney, chief deputy director for the Caltrans District 4 office in Oakland, estimated recently that the 2.3-mi.-long project, which got under way in January 2002, will be finished in late 2009 or early 2010.

	Photo by John Huseby

"The contractors might be able to move the work ahead of the 2010 completion date, and finish the work before that date," McElhinney added. "We'll just have to see as we progress."

Caltrans is replacing the 68-year-old eastern half of the 4.5-mi. bridge because a segment of the cantilever- designed structure collapsed during the deadly October 1989 Loma Prieta Earthquake.

Structural analysis determined that Caltrans needed to replace the bridge with one that could remain standing and open to emergency vehicles in the aftermath of a massive tremor.

The joint venture team of the San Francisco office of T.Y. Lin International and Los Angles-based Moffat & Nichol, in association with New York City-based Weidlinger Associates Inc., designed the new structure. McElhinney said the new span would change the skyline of San Francisco Bay.

It will be wide enough to fit five lanes of traffic in each direction, plus an emergency lane. There also will be a bike lane and pedestrian right-of-way. McElhinney said the epic construction project has been divided into 16 separate contracts, seven of which have been awarded.

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KFM-a joint-venture partnership consisting of Kiewit Pacific of Vancouver, Wash., the San Jose-based northern division of FCI Constructors and Seattle-based Manson Construction Co.-had won three of the five largest contracts awarded as of mid-May. The contract for the construction of the world's first single-tower, self-anchored suspension bridge will be awarded in the fall.

Caltrans recently awarded a $71 million contract to Rancho Cordova-based C.C. Myers Inc. for the construction of the south-side, temporary-highway platform, leading from the Yerba Buena Island to the actual suspension bridge.

Once traffic is flowing over the new East Span, McElhinney said the agency would award a contract to dismantle the existing bridge sometime in 2010 or 2011.

Most of the work to date has focused on the skyway, a 1.2-mi.-long stretch that features a side-by-side deck gradually rising up from the Oakland side of San Francisco Bay to Yerba Buena Island.

The $1-billion steel and pre-cast concrete structure is gigantic by any measure, McElhinney said.

"KFM is building 28 piers to support the decks, each a major undertaking. First, crews erect cofferdams in the bay then pump out the water before placing steel and concrete footing boxes over gravel foundations.

	Ironworkers building a rebar form in the Oakland Skyway yard (Photo by John Huseby)

Once this is done, workers ram 9 mi. of 8-ft.-diameter steel piles 300 ft. through mud to bedrock, using some of the largest cranes and pile drivers available on the West Coast. Bird-like barge-born cranes pound the piles into the ground at an angle to better withstand the lateral forces of a major tremor.

Crews reinforce the inside of the tube-like pilings with concrete poured over rebar cages. The Water Transmission Group of Ameron International supplied most of the 2- to 3-in.-thick steel casings from its Fontana heavy-steel manufacturing plant.

Bill Sloane, an Ameron vice president, said the 74,000-ton order was the biggest it has ever received for a bridge project. "We supplied the pilings for the widening of the San Mateo Bridge, but it was nothing of this magnitude," he added.

		A view of casting forms and gantry crane at the Skyway precast yard in Stockton. Roadway sections for the new east span will be fabricated on casting forms like these (photo by Govind Friedland).

Sloane said that after the pilings are fabricated, Ameron ships them by rail to Mare Island in Vallejo where XKT Engineering welds the lengths into 100-ft. and 200-ft. sections. XKT then loads them onto barges and sends them to the site.

Sloane said each completed casing section weighs up to 230 tons and requires extra care in the welds when the sections are joined together.

Alfred Bottini, president of XKT, which is based in Vallejo, said the order was impressive, but wasn't the largest his facility had tackled.

"These pieces aren't particularly odd," he added. "They are some of the bigger pieces we've done, but we've done larger diameters and heavier pieces in the past."