Granite Reconstructs U.S. 1 in the Keys

Granite Construction rebuilds U.S. Route 1 to make it safer and more environmentally friendly.

By Debra Wood

When Florida pioneer and rail baron Henry Flagler pushed his Florida East Coast Railway south to Key West in the early 1900s, his engineers and laborers gave little thought to the environmental impact of their dredging and filling.

Today, Granite Construction of Tampa is reconstructing a 7-mi stretch in Key Largo of what became the Overseas Highway, and the firm is protecting crocodiles and other endangered species and restoring natural water flow.

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“This job borders the Everglades National Park and environmental issues are a major concern,” says Michael Derksen, project manager with Granite. “We’ve had to take a proactive approach.”

For nearly 20 years, the Florida Department of Transportation had planned to improve the two-lane highway, which has a long history of fatal accidents and is the only route on or off the hurricane-prone Florida Keys. Throughout that time, as various plans for four-, three- and two-lane enhancements came and went, Granite and others in the industry kept an eye on its progress, says Tom Boyle, project executive for Granite.

Granite teamed with Jacobs Civil of Miami in 2003 in anticipation of the project being advertised by FDOT as a design-build job. In 2004, with permits in hand for a two-lane replacement bridge over Jewfish Creek, linking the Keys to the mainland, the department sought bidders for the project.

Boyle says he saw it as a good fit for the company, with its mix of bridge and roadwork. Granite received the $147.8 million contract in 2004, with a January 2005 start. The company has self-performed all of the civil work.

Overview

The project includes construction of a 1.5-mi-long bridge, replacing the 1944-era, bascule bridge at Jewfish Creek and a causeway crossing Lake Surprise. It also includes widening of the existing road, for 5 mi north of the bridge and 2 mi south of it. The reconstructed section includes two 12-ft travel lanes, separated by a concrete median; a 10-ft northbound shoulder that can convert to a travel lane during hurricane evacuations; and an 8-ft southbound shoulder.

“This is a significant project for the local residents that will allow more efficient and effective [hurricane] evacuations,” Derksen says.

Mindful of the environmental sensitivities, Granite educated its workforce about the importance of dealing with manatees, sea turtles, dolphins, osprey, crocodiles and snakes in “an appropriate manner” and not to do anything that could be considered harassment. In addition, the contractor took care to remain within clearing limits and not to disturb indigenous and endangered mangroves.

Jewfish Creek Bridge

A high-level bridge, with 65-ft clearance, now spans Jewfish Creek and then continues as a low-level bridge over Lake Surprise. Sailboats and other watercraft will be able to pass under the structure even during hurricane warnings. Currently, the drawbridge is locked down during the storms.

“A 7,500-ft bridge replaces a 300-ft-long drawbridge because we are replacing existing road fill,” says John Larson, senior project manager with Jacobs Civil.

Granite will excavate and remove from the water the former causeway built by Flagler’s team. Sea grass is expected to fill in, and crocodiles and manatees will be able to move about in the saltwater lake.

“There is no channel between the two sides [of the lake], and it’s a habitat for the American crocodile,” Larson says. “It opens the water body up to improve the quality of the water in the lake and enhance the habitat for an endangered species.”

The bridge foundation features about 260 48-in. and 60-in. drilled shafts and 69 piers. The work took place from floating platforms.

Mindful of the environmental impact of the construction project, crews had minimal access to build the new structure. It was extremely tight for cranes, which worked off a trestle bridge built perpendicular to the roadway. The cranes set more than 450 beams at night to lessen disruption to traffic.

Standard Concrete Products of Tampa cast the 92 78-in Florida modified bulb-T beams, the 343 72-in Florida modified Bulb-T beams and the 29 AASHTO type IV prestressed beams. Trucks brought some to the project, but others, including the 160-ft-long center span, were shipped by barges from Tampa to Key Largo.

Granite completed the bridge and opened the northbound lane to two-way traffic in May, before the hurricane season began.

Four ramps in a tight diamond pattern, now under construction, will provide access to businesses around Jewfish Creek. Beams for the ramps are set using a long hydraulic crane sitting on the completed bridge. The ramps from the southbound lane lead to a rotary intersection.

“We didn’t have enough room once we were off the bridge ramps to make a right turn without going over the right of way, so we come down to a roundabout,” Larson says.

Boyle anticipates beginning demolition of the old bascule bridge in October. The company will remove its two foundations from the creek to allow water to flow more naturally again, and it will restore the shoreline.

The Road North

Granite teamed early with Hayward Baker, a geotechnical construction firm in Tampa, to provide a solution to managing the mucky, organic soils needed to widen the roadbed north of the Jewfish Bridge.

Hayward Baker devised and carried out a strengthening, soil-mixing process that allowed for road building on top of the existing muck, rather than surcharging or hauling out the unsuitable soil. Crews used a rototiller-like device on a backhoe boom to pump in a mixture of 25% cement and 75% slag and mix it up with the existing soil to a depth of 10 ft, when they hit rock. When the mixture hardened, it was strong enough to support the road.

“The operator drags the rototiller underground in the soft material, back and forth and up and down, until he puts in the prescribed amount of cement and slag,” Larson says.

Larson says he is not aware of any other jobs in the United States that have used the methodology. A Hayward Baker sister company had performed similar work in Europe.

“That was a key factor of us being successful on the job,” Boyle says. “FDOT District 6 liked the idea and was willing to give it a try.

Granite crews placed 6 ft of fill on top of the mixture and built the road. The Cemex Card Sound Mine in Florida City, Fla., supplied the lime rock for the roadbed and the ready mix for the bridge. Granite milled the old asphalt and blended it with new to reconstruct the existing lanes.

Along this section of U.S. 1, north of the bridge, Granite built nine box culverts to allow crocodiles to pass under the road. That work is now complete.

The contract completion date is Aug. 5, 2009, with a milestone date and a $2.4 million bonus tied to a June 12, 2009, finish. Granite expects to earn it and plans to wrap up construction during the first quarter of 2009.

Jewfish Creek Project Team:

Owner: Florida Department of Transportation
Construction Engineering and Inspection: Parsons Brinkerhoff, Miami
Design Build Contractor: Granite Construction, Tampa
Engineer: Jacobs Civil, Miami
Soil Mix Contractor: Hayward Baker, Tampa
Precast Beams: Standard Concrete Products, Tampa

Useful Sources:

Granite Construction
http://www.graniteconstruction.com/about-us/hcd-project-detail.cfm?LocationID=309&ProjectType=Design-Build,Highway-Bridge