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TRANSACTIONS NEWSLETTER ONLINE

October/November 2007

Sleek and Sturdy:
New Benicia-Martinez Span Opens to Traffic

Photo: John Huseby, Caltrans

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Hundreds of celebrants gathered in the historic towns of Benicia and Martinez early on a Saturday morning in late August to welcome the latest addition to the San Francisco Bay Area's necklace of bridges: the new span of the Benicia-Martinez Bridge. The Congressman George Miller Bridge, as the new structure has been named by the state Legislature, stands just to the east of the original Benicia-Martinez Bridge, and is designed to significantly increase the capacity of this crossing over the Carquinez Strait.

The highlight of the event was a festive inaugural ride that launched from Martinez, with Congressman Miller in the lead.

“This span is much more than concrete and steel,” said Miller. “It is a tribute to our engineers, skilled labor force and civic leaders who worked through challenging obstacles to see it to completion. It is a tribute to our communities that have supported the concept and to our residents who have paid for it. It is also a symbol of the growth of our region and the health of our economy.”

Handsome and High Tech: New Toll Plaza Makes a Statement

From some vantage points, it resembles the Starship Enterprise, a grand circular presence hovering at the southern edge of the new Benicia-Martinez Bridge span. From others, it looks more like one of the conventional ships that ply the waters of the Carquinez Strait below. Retro and futuristic at the same time, the new toll plaza at the Benicia-Martinez Bridge stands as an iconic gateway at the intersection of Solano and Contra Costa counties.

Caltrans Senior Architect David Stow said his design team took their cues from the setting and the environment. “The shape was drawn from the softness of the undulating hills, and the way the river touches the land, gently carving coves,” he said.

Meanwhile, the canopy floating over the 11 toll lanes is “battered,” meaning it slopes in. “When you're looking up at the canopy, it gives you the feeling of the bow of a large vessel,” Stow said.

Both the toll plaza and the equally curvy administration building that intersects with it are clad in aluminum panels that alternate between tones of green and copper — reflecting the golden hues of the summer hillsides and the lush winter landscape along the strait. — Brenda Kahn

Technical Glitches Inspire Creative Solutions

With its sleek, curved sweep of concrete, the new span may look simple to build compared to its more ornate counterparts around the Bay. But the structure represents a triumph over technical and environmental hurdles that doubled the initial construction schedule along with project costs, and inspired Caltrans and the construction company's engineers to come up with creative solutions.

Early on, shock waves from pile driving threatened migratory fish species traveling along this key waterway. Engineers surrounded the underwater piles with a clever “bubble curtain” that mimicked a Jacuzzi and shielded the migrating fish — and that has become the standard for future such operations. The project also was bedeviled by unstable bedrock that caused underwater holes drilled for foundation piers to cave in.

Engineers then encountered problems with the lightweight concrete for the span, with the initial “cast-in-place” segments overheating as they cured. When mixing ice and liquid nitrogen with the concrete didn't work, crews installed tubes through the segments to cool the mixture with Bay water.

The new 1.2-mile viaduct carries five lanes of northbound Interstate 680 traffic. For now, the 1962 span carries three lanes of southbound traffic, but over the next two years, Caltrans will reconfigure the 1962 bridge to handle four lanes of southbound traffic along with two shoulders and a bicycle/pedestrian path. This latter feature will be an important link in the regional Bay Trail that rings San Francisco and San Pablo bays.

Twin Spans Honor Father-Son Lawmaker Pair

It was partly his role in troubleshooting the technical and environmental glitches surrounding the bridge's construction that earned Miller the recognition of his fellow legislators. But there were other factors at play as well: Miller has deep roots in the area, and the older bridge is named for his father, the late George Miller Jr., who represented Contra Costa County in the state Assembly from 1947 to 1948, and in the state Senate from 1949 until his death in 1969.

“This pair of bridges is a tribute to generations of outstanding public service by the Miller family,” said Steve Heminger, executive director of MTC and its Bay Area Toll Authority offshoot, which played a key role in financing the new span and overseeing construction. “Nowhere else in California, and perhaps nowhere in the world, are there two major bridges, side by side, named for a father and son.”

Designated as a “lifeline structure” due to its strategic location with easy access to nearby Travis Air Force Base, the new span is built to withstand a maximum credible earthquake.

Not surprisingly, the increase in capacity has had a positive effect on traffic. “The previous delays that could stretch back to Highway 4 almost instantly disappeared with the opening of the new bridge,” said veteran Bay Area traffic reporter Stan Burford (with KGO Newstalk AM 810).

Bay Area voters agreed to pay for the New Benicia-Martinez Bridge Project in 1988 when they passed the MTC-sponsored Regional Measure 1, which raised tolls in order to fund a package of critical bridge expansion and rehabilitation projects. MTC oversees delivery of the projects in its role as the Bay Area Toll Authority. The $1.2 billion price tag encompassed construction of an all-new interchange between Interstate 680 and Interstate 780 in Benicia, reconstruction of the I-680/Marina Vista interchange in Martinez, and a striking new toll plaza on the Martinez side of the bridge (see adjacent story).

FasTrak® Express Debuts

The new toll plaza is as high-tech as it looks: There are two “open-road tolling” lanes on the left side of the toll plaza that allow cars equipped with FasTrak® electronic toll tags to pass through at highway speeds (other lanes accept both cash or FasTrak®). A first for the Bay Area, these “FasTrak® Express” lanes increase vehicle throughput by 50 percent above a regular electronic toll lane.

As is the case with FasTrak® electronic toll collection at all of the region's bridges, overhead antennae read toll tags and a computer system automatically deducts tolls from motorists' prepaid accounts.
— Brenda Kahn

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