The Pensacola Bay Bridge has reached the midway milestone, and the recent opening of the eastbound span is giving motorists a taste of what the wider crossing will be like when the bridge is fully completed in two years.

The $425 million bridge will feature two separate spans for eastbound and westbound traffic along Route 30 (U.S. 98), connecting the city of Pensacola to Gulf Breeze. It runs parallel to the four-lane structure it will replace, which first opened to traffic in October 1960 and accommodates 55,000 vehicles a day, creating frequent traffic congestion.

WSP USA and Skanska USA serve as the design-build team on behalf of the Florida Department of Transportation (FDOT).

“This is a major transportation corridor, a primary hurricane evacuation route, and a popular roadway for travelers on their way to Pensacola Beach along the Gulf of Mexico,” said John Poulson, WSP vice president. “It has been exciting to see the momentum maintained at a high level with this complex, signature project, especially for the senior staff who have enjoyed watching the next generation of engineers and designers doing much of the heavy lifting to make the project a success.”

Each span will provide increased traffic capacity through three, 12-foot-wide travel lanes, alongside 10-foot-wide inside and outside shoulders. Each span will also accommodate pedestrian and bicycle traffic with a 10-foot-wide multiuse path separated from motorized vehicular traffic with a barrier wall.

The eastbound lanes of traffic shifted from the old span to the new bridge on Sept. 4, with the westbound lanes switching four days later. Design work began August 2016 and construction of the eastbound span began in the spring of 2017.

This is the third bridge to cross the Pensacola Bay. The first, a two-lane bascule bridge that opened in 1931, served motorists until the second bridge opened nearly 30 years later.

The bridge is being constructed in challenging geotechnical and marine site conditions—a highly corrosive coastal environment across an open, exposed bay. Its expansive length poses unique challenges, including ship impact and hydraulic design requirements.

“Resiliency criteria dictated a ‘service immediate’ level to ensure the bridge would always be available as a hurricane evacuation route capable of handling high levels of traffic,” said Charles Rudie, WSP USA assistant vice president. “Major storm events cause significant scour, wind-generated wave loading, and can produce 150-mile-per-hour hurricane wind forces on the structure.”

These conditions, coupled with the significant ship impact forces and water depths reaching 30 to 35 feet, placed a series of stringent demands on the structural system.

The geology of the site created challenges for the structure’s foundation, with a highly variable subsurface consisting of an overburden layer of 30 to 40 feet of silty sand, and a bearing layer of medium dense layers located from 120 to 250 feet deep.

“A major goal from the start was to minimize the footprint of the low-level piers so that pre-casting of the pier elements could be maximized,” Rudie added. “The connections to the precast concrete substructure units employ corrugated steel ducts cast in the head of the pile, which can easily be extended in the field if bearing is achieved, or used for field spices in the event the pile does not achieve capacity.”

Taking advantage of a modified pile design reduced the required number of piles by more than 20 percent, resulting in about 2,000 piles covering the entire six miles of bridge’s two spans.

Because of the importance of the bridge for the region, an emphasis was placed on completing the entire 2.26 million-square-foot bridge within a four-year period.

“To meet the owner’s expected design and construction schedule, the team had to maintain a construction average pace of 1,300 square feet of new bridge per contract day,” Rudie said. “In preparation, the teams developed specific design and construction approaches to create the best opportunities to meet that schedule.”

Once traffic moves to the new span, the current bridge will be demolished, and construction of the westbound span will begin. The project also includes reconstruction of the highway approaching the bridge and improvements to public facilities in the Gulf Breeze Wayside Park.

The design provides several landmark aesthetic features, including a wishbone tied-arch main span and multi-color aesthetic lighting that will create a ribbon of light across the bay.

“The arches are designed to maximize the visual impact from all perspectives while also being durable and easily maintained,” Poulson said. “The architectural details of the tower-supported shade structures and piers mimic the arch’s wishbone, providing scenic views from both the low- and high-level segments of the bridge.”

While pedestrian paths on bridges are common, the use of paths on both sides of the bridge is rather unusual. The decision to provide dual pedestrian paths was driven by strong community involvement in the design process.

“These paths will feature scenic overlooks and shade structures in addition to educational plaques and other features selected by the community to highlight the local area and history, encouraging walkers and cyclists to explore the bridge and enjoy the journey from shore-to-shore,” Poulson said.

Attention now turns toward the construction of the westbound span bridge. The entire bridge is scheduled for completion by mid-2021.

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