A Roaring Restoration

Project Contractors, Engineers are Going to Unusual Lengths for Long-Needed Project

By Debra Wood

Contractors are all over the Bridge of Lions, a landmark in the “Nation’s Oldest City” of St. Augustine, Fla., fortifying foundations, rejuvenating girders and delivering a new bascule to improve safety while maintaining the historic structure’s original architectural features.

“This bridge really contributes significantly to the overall character of this historic city,” says David Sweeney, vice president and project manager for lead design consultant Reynolds, Smith and Hills of Jacksonville. “Most St. Augustine residents think of this bridge as a historic icon for their community.”

Listed on the National Register of Historic Places, the 1,545-ft-long, 1920s-era Mediterranean Revival-style bridge spans the Matanzas River (the Intracoastal Waterway) and connects downtown St. Augustine with Anastasia Island. It began falling into disrepair in the 1980s, Sweeney says.

The Florida Department of Transportation continued to maintain the bridge while seeking a permanent solution, considering engineering and environmental issues as well as the bridge’s importance in the community.

“The condition driving the rehabilitation of the bridge is the failing of the foundation,” says Jeff Williams, FDOT project manager. “The bridge was sinking away.”

Over the years, FDOT had discussed with the city replacing the bridge or restoring it. Community debate raged for years without reaching a consensus on a final resolution, but finally FDOT decided on the $76 million rehabilitation.

“We are taking an entire bridge apart completely, with the exception of the bascule piers, and putting it back together, so it looks identical to when it was constructed,” adds Jack Haynes, RS&H bridge services group leader. “It’s an incredible project. The codes and criteria we use are not written for this type of construction project.”

The bridge will remain one lane in each direction, with the new approach lanes 11-ft rather than 10-ft wide. The bridge also will gain bike lanes and a safety barrier between the pedestrians and the traffic.

“It’s a unique project from the historical perspective and challenging from the technical perspective because there are so many different types of work involved,” says Tom Fulton, project executive for general contractor Skanska USA Civil Southeast of Virginia Beach, Va. Fulton adds that the job calls for ornamental concrete work, drilled shafts, a draw span and other features, with all of the work taking place in a challenging marine environment in a prominent tourist area.

Skanska began working on the rehabilitation and widening project in February 2005 and anticipates finishing it by Feb. 12, 2010. However, Fulton says the company is shooting for an early completion in August 2009 to earn a $1 million milestone bonus. The contract offers four bonus opportunities. Fulton calls the schedule aggressive when those bonus milestones are taken into account.

The project began with the construction of a 1,600-ft temporary bridge, sitting atop a foundation consisting of 120 24-in. piles, and with a concrete deck and an 80-ft, vertical-lift, movable, open-grate channel span to maintain vehicular and boat traffic.

“The temporary bridge is more substantial than what we normally use for a temporary bridge because we wanted to make sure it performed for the (length of) time needed for rehabilitation,” says Craig Teal, senior project manager for FDOT.

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The Approaches

The existing concrete approach piers had deteriorated to the point they could not be rehabilitated. Skanska removed and is replacing the 14 western and nine eastern approach piers with new concrete that replicates the elephantine columns and partial web wall bents of the former piers and accommodates a wider bridge and current scour and ship-impact codes.

Historians considered the arched approach girders aesthetically significant, so the new bridge will incorporate them. Sweeney calls their rehabilitation one of the most significant design challenges.

“From a historical perspective, replication does not have as much value as reuse,” Sweeney says.

Skanska disassembled the steel-riveted girders and transported them to Florida Structural Steel in Lakeland for rehabilitation. They will be sandblasted, and then new steel will be added and painted. The arch girders will be brought back and erected on the new approach piers, and a new concrete deck poured.

However, the arched girders will not provide the only support. They were designed to 1927 standards, not current codes. Because they did not provide redundancy and carried the load transversely, RS&H designed an interior strengthening system that will support the load longitudinally. For purposes of the historic rehabilitation, they are parallel to the arch girders but shallower in depth and hidden from public view.

The Bascule Piers

The bascule piers and octagonal observation towers, significant historical elements, are receiving strengthened foundations to meet current ship-impact standards. Crews will place four drilled shafts around the edge and one in the middle of the fixed piers, within the existing footprint to avoid decreasing the width of the 79-ft, 6-in.-wide channel.

“We will be adding to the existing pier, encasing the foundation and transferring the load to the new foundation,” Fulton says. Skanska had drilled three of the five shafts on the pier closest to St. Augustine in April.

The design team opted for drilled shafts, rather than pile driving, to avoid damaging the historic structure and to eliminate banging in the tourist area.

“With driven piles, the impact from the hammer has the potential to cause damage,” Fulton says.

The observation towers will receive a facelift. Crews will chip away the concrete to about 1 in. below the rebar, install a low-voltage protection system that uses a DC current to keep the rebar from rusting and then apply a new concrete veneer. The towers also will receive rehabbed clay-tile roofs and glass windows.

The new bascule span steel framing and deck will appear similar to the one Skanska removed. It will have all new machinery and electrical components.

Completion of all of the bridge’s drilled shafts, on the bascule and other piers, by this Aug. 6 would earn Skanska another $1 million bonus. Fulton estimates the company had completed 60 percent of the shafts in April. Skanska will earn an additional $500,000 bonus for removing the temporary lift span and adjacent spans within 60 days of starting the work.

The project also calls for replication of the 1920s-era lanterns and ornamental railings, which were removed during a 1970s rehabilitation. The land on the western approach to the bridge will receive more landscaping and will be brought back to its 1920s appearance. A new park will be created on the eastern side.

Of the overall project, RS&H’s Haynes says, “I cannot think or conceive of anything like this project ever having been done before or being done again,” Hayes adds. “It’s really unique to be a part of it.”

Bridge of Lions Project Team:

Owner: Florida Department of Transportation

Contractor: Skanska USA Civil Southeast, Virginia Beach, Va.

Prime Design Consultant: Reynolds, Smith and Hills Inc., Jacksonville

Construction Engineering and Inspection: URS Construction Services, Tampa

Historic Architecture: Kenneth Smith Architects, Jacksonville