At first glance, the replacement of a 2,400-ft. bridge over the Trout River in Jacksonville, FL, may seem like a run-of-the-mill job.
But what adds “spice” and “danger” to this project, according to Earl Miles, bridge assistant superintendent at Hal Jones Contractor Inc. in Jacksonville, are the piles.
Each one is 54 in. in diameter, with lengths up to 100 ft. and weight of more than 70 tons. Add to this a pile driving hammer that comes in at 75 tons and now you have a project that requires some large equipment.
The bridge replacement is a part of a 3-mi. project along Interstate 95 that will widen it from two to three lanes. Most of the $54-million project is bridgework, but road replacement is integral as well. The roadwork has been subbed out to J.B. Coxwell of Jacksonville.
Work began in March 2005 and must be completed within 1,000 days.
As in most interstate projects, one of the main challenges of this job is a restricted right of way and access to the project. It is particularly challenging in this respect because of the marshes on both sides of the Trout River. On the north side of the river, the contractor built a 700-ft. trestle and a 600 ft. one on the south side — long enough to reach water in which barges could float.
Space is most restricted on the north side, where access is restricted by a city park. And the challenge doesn’t get any easier in the river. Barge access to the site is restricted both horizontally and vertically by two existing bridges east of the project. The structures have limited barge width to a maximum of 45 ft.
After the first 45 ft. barge arrived at the job site, 20-ft.-wide pontoons were added to each side to make it 85-by-150-ft.
A Kobelco CK 2500 250-ton crane, upgraded to 275 tons, was walked onto the barge from the trestle. This became the pile driving rig that handled the 75-ton APE 400 hammer and 70-ton plus 54-in. cylinder piles. A second Kobelco crane works from the north and south trestles.
Other equipment on the project includes a Link-Belt LS240H 200-ton crane on a 45-by 150-ft. barge, a Link-Belt LS240H 200-ton crane, a Link-Belt LS218 100-ton crane and several smaller barges.
Mobro Marine, of Green Cove Springs, FL, provided the barges. All of the cranes, as well as the APE hammer, are owned by the contractor.
The APE 400 has a ram weighing in at 80,000 lbs. and develops 360,000 ft./lbs. of energy with a maximum stroke of 4 ft.
The trestles were built working out from the land in 55-ft. sections. As each section was built, a crane moved out and continued driving piles and placing the concrete decking. The trestles will be removed after the first phase of the project is completed and reinstalled after the existing bridge is removed for construction of Phase 2.
Once the 54-in. diameter cylinder piles are driven to bearing, they are cut to proper elevation and the top 10 ft. is filled with concrete.
Standard Concrete Products in Savannah, GA, is precasting the piles and the “Bulb T” beams, which are 140 ft. long, 78 in. high and weigh 80 tons apiece. Two cranes are required to set them.
Traffic phasing has been very difficult on all parts of the project, but especially the work on land. Crews are required to keep four lanes of interstate open at all times. They do the lane shifts at night and also set the beams for the three land bridges. An American 7460 90-ton is used at the bridge widening for pile driving and setting beams.
Retention ponds on site are providing most of the fill for the new embankments. Very little dirt has to be hauled in from off site.
Greg Bedenbaugh is project superintendent and Dennis Harrison is project manager. CEG Staff
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