2010 Top 10 Bridges - No. 4

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UPDATING AN ICON - Work preserves historic character with vital upgrades

 

PROJECT: Bridge of Lions Rehabilitation
LOCATION: St. Augustine, Fla.
OWNER: Florida DOT
DESIGNERS: RS&H (engineer of record) and TranSystems (bascule span)
CONTRACTOR: Skanska USA Civil Southeast
COST: $76.8 million
START DATE: May 26, 2006
COMPLETION DATE: March 17, 2010
 
Rehabilitating Florida’s Bridge of Lions may have started in 2006, but the project was decades in the making.
 
Originally opened in 1927, the 1,574-ft icon links downtown St. Augustine to Anastasia Island and is listed on the National Register of Historic Places. Giant marble lions guard the entrance, and fl owing arched girders and Mediterranean-style bascule towers make for a striking foreground to the city’s skyline. But the city’s largest fire truck was heavier than the 15-ton limit, and the bridge did not meet current criteria for scour and ship impact.
 
Jack Haynes, project manager for RS&H, grew up in Jacksonville and remembers people debating for decades whether to replace the bridge or rehabilitate it.
 
Craig Teal, the Florida Department of Transportation’s project manager, told ROADS & BRIDGES that one of the biggest challenges was preserving the historic architecture while bringing it to 2010 standards. 
 
“There were some elements in the community that wanted us to go strictly to restoration,” Teal said. “So we had to balance that to be able to keep it a modern structure but yet still keep those original elements.”
 
The rehabilitation became somewhat of a compromise. One of the requirements was that the builders bring the bridge back to 1927 as far as possible.
 
Shutting the bridge down entirely would have crippled the local economy and forced drivers to make a long detour. So to keep traffic flowing, the team built a 1,600-ft temporary bridge and shipped the original elements to a facility to be inventoried and repaired. More than 380 tons of structural steel was recycled in the process.
 
An interior system of girders also had to be designed to fit in the existing bridge and carry a heavier load. Doing so meant digging pier foundations that went 75 ft deeper than before. The builders could not simply shut down the channel, so before they could lay the new foundation, the team had to erect a cofferdam and de-water the area so that ships could still pass through during construction. The team also coated the structural steel girders with molten zinc, which more than doubles the time between coatings. Safer, ADA-compliant sidewalks and ramps also were installed.
 
All the work adds up to what Haynes calls a truly unique project.
 
“I don’t think you’ll ever see another job quite like this,” he said. “Unless they do it again in 80 years.” 
 
Although it is 3 ft wider, the rehabilitated bridge closely mirrors the original, despite limited plans from 1927. The team even managed to fi nd the original paint color, which
was no easy feat, given that all the original pictures were black and white.
 
At the time of publication, the contractor was finishing landscaping work, and the iconic lions should be brought back in mid-2011.

 

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