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Vallejo Opens Largest U.S. Suspension Bridge Since ’73

Thu November 13, 2003 - West Edition
CEG



VALLEJO, CA (AP) With speeches, parades and a blowtorch, Californians opened America’s first major suspension bridge since 1973, a 3,400-ft. (1,020 m) span across the Carquinez Straits 25 mi. (40 km) northeast of San Francisco.

Gov. Gray Davis helped ironworkers christen the Alfred Zampa Memorial Bridge Nov. 8 by slicing through a ceremonial chain with a blast of fire.

State officials held the ceremony a week earlier than originally scheduled to give the honor to Davis, who presided over the bridge’s construction and leaves office Nov. 17 after voters recalled him last month.

The $400-million bridge is 410 ft. (123 m) high, rests on two piers and is designed to withstand an earthquake with a magnitude of 8.0. According to Parsons, the general contractor, the bridge is 3,464 ft. (1059 m) long, and incorporates state-of-the-art advancements in the design of orthotropic steel box girders. The closed steel box girder of the suspended superstructure is 10 ft. (3 m) deep and 95 ft. (29 m) wide, and is the first of its type in the United States.

The span is named for a local ironworker who fell from the Golden Gate Bridge during its 1936 construction and survived to build six more bridges in the Bay Area.

Zampa died at 95, weeks after turning the first shovel of dirt for the bridge in 2000. The bridge named for him is the longest suspension span to open in the United States since Maryland’s Chesapeake Bay Bridge.

More than two dozen members of Zampa’s iron-working family attended the Nov. 8 ceremony, including his grandson, Dick Zampa Jr., 47, who sliced the thick iron chain with an oxyacetylene torch.

The Zampa replaces a seismically risky 1927 bridge, a cantilevered steel structure that carries eastbound traffic on Interstate 80. The route is increasingly crowded with commuters driving home to new suburbs between the Bay Area and Sacramento.

Eastbound traffic began using the new bridge Nov. 9, while a span built in 1958 will continue to carry westbound vehicles.

Historical Background

The two structures that have been used to bridge the Carquinez Straits in recent decades have played an important role in the Bay Area’s transportation network and have been used by more than 109,000 drivers each day. But realizing that those bridges no longer met current seismic design or traffic safety standards, officials embarked on two major projects to address the following needs:

• satisfy current seismic and safety standards;

• correct existing roadway deficiencies;

• improve traffic safety;

• maintain routes for local, regional, and interstate truck freight movement;

• encourage use of alternate modes and support HOV use.

The first project involved retrofitting the existing eastbound bridge built in 1958 for safety and seismic stability. The second project replaced the existing westbound 1927 bridge with the Zampa bridge.

The Zampa project was financed by Regional Measure One funds, a mandate passed by voters in 1988 to increase tolls on Bay Area bridges to fund improvements to bridge structures and their approaches. The replacement of the Carquinez Bridge Western Span was specifically identified as one of the projects to be funded by this measure.

The eastbound Carquinez Bridge was built in 1958 as part of the route’s upgrade to interstate status. The bridge has carried up to 53,000 vehicles per day in four eastbound lanes. The total bridge width is 52 ft., including 12-ft. lanes and two 2-ft. shoulders. The cantilever steel truss spans a total of 3,300 ft. in length at 140 ft. above the channel.

The cost of retrofitting the 1958 structure was $70 million. The contract for this project was awarded in June 1998 to Balfour Beatty Construction Inc. of Vallejo, CA. Balfour Beatty began preliminary work on June 1998.

This project facilitated the following upgrades:

• replace or strengthen the steel truss members in the bridge towers;

• reinforce pile foundations of Pier 5 at the south end of the bridge;

• retrofit the abutment where the bridge touches down on the northern end;

• strengthen the eastbound on/off ramps and approach structure.

The western bridge constructed in 1927 as a private toll bridge has provided three lanes of westbound (to San Francisco) traffic, but in recent years began to exhibit deterioration of its metal components. Accessibility to and maintenance of the bridge’s structural members was difficult, and major rehabilitation was virtually impossible while the bridge was being used for traffic. Therefore retrofit of the existing structure was rejected in favor of replacement.

Now that the Zampas bridge is complete, workers are expected to remove the 1927 bridge in the near future.