Faced with growing traffic on a pair of bridges crossing the Alabama River in Montgomery, Ala., state Department of Transportation officials decided to bridge the widening gap between their designed capacity and increasing demand by bridging the actual gap between the two structures.
“In essence, you’re taking two separate bridges and turning them into one big bridge,” said ALDOT spokesman Tony Harris, explaining the roughly half-mile (0.8 km) span of Interstate 65 was widened by building up between the two bridges to create two additional traffic lanes — one northbound and one southbound — that will be divided by a concrete barrier wall.
While it seems like one big bridge, the new Alabama River Bridge is actually three independent bridges next to one other, said John Dowdell, safety manager of Lexington, Ky.-based R.R. Dawson Bridge Company, which won the low-bid contract for the $13.25 million job, including the bridge widening and approaches.
“Each moves differently as traffic goes over,” Dowdell said. “That’s the way it’s designed.”
Having three bridges create one mega-bridge made sense because the two circa 1970s bridges were nowhere near their life expectancy, and interstate realignment is so costly, new alignment construction was not an option, Harris said.
R.R. Dawson, which has an office in Bessemer, Ala., began the job in May 2006 and essentially finished in June, six months ahead of the expected completion date of December 2007, Dowdell said.
All that remains to be completed is putting in the barrier rail to divide the northbound and southbound lanes, he said.
Dowdell credits two 40-ton (36 t) Mi-Jack Travelift rubber tire gantry cranes for streamlining the work so it could be completed ahead of schedule.
“They just worked super,” he said. “By utilizing the Travelift cranes, we were able to reduce the cost of the project by 20 percent, thus passing along the savings to the taxpayer.”
The MJ40 Travelift cranes, rented through Chicago-based Mi-Jack’s Augusta, Ga., office, were used to build the bridge superstructure, Dowdell said, adding that service for the cranes was excellent.
The way the Travelift cranes rode on the existing structures, straddling the gap between the original two bridges, allowed work to progress without having to close traffic lanes, Dowdell said.
Moreover, they didn’t have to transport cranes to other areas of the project, he said.
Together, that moved along the work and minimized the impact on the community, Dowdell said.
The I-65 bridge crosses three CSX-owned rail lines as well as the river, he said.
R.R. Dawson had 25 workers on the project, and 13 subcontractors were used for jobs ranging from steel erection and drill shafts to painting and traffic control, Dowdell said.
Construction required 749 tons (679 t) of structural steel and 1.3 million lbs. (590,000 kg) of reinforcing steel, he said. A total of 14,800 linear ft. (4,500 m) of piling was driven.
Some piles were driven to a depth of 40 ft. (12 m), while others were driven to between 80 and 90 ft. (24 and 27 m), depending on what was needed to get the proper support for the footer, or column base, Dowdell said.
The drill shafts — three 9 ft. (2.7 m) in diameter and 90 ft. (27 m) deep and three 11 ft. (3.4 m) in diameter and 90 ft. (27 m) deep — required three cranes on barges, Dowdell said.
Two Manitowoc cranes, a 999 and a 777, were used along with a Link-Belt RT 8050 tender crane, purchased from its Lexington-based manufacturer, for the drill shafts, he said. Case Atlantic Company performed the work.
The project entailed pouring 4,627 cu. yds. (3,500 cu m) of concrete and placing 8,880 linear ft. (2,700 m) of concrete beams, Dowdell said.
To create a column on top of a footer, a rebar cage was stood upright, a form was placed around it, and concrete was poured, he said. A total of 34 columns (17 pairs) were constructed.
The Travelift cranes were used for several applications, including setting girders, Dowdell said.
Because of the weight of the girders, both had to be used together, he said.
In addition to the Travelift cranes, which the company used for the first time on this job, Dowdell credits R.R. Dawson’s approach to bridge building for the work’s early completion.
“We kind of set it up like an assembly line,” he explained.
It starts with the footer phase, he said. A crew comes in to put in the first footer, and, when it’s finished, moves on to the next section and starts on the second footer.
At that point, a crew of column builders comes in behind the footer crew and builds a column on the first footer, Dowdell said. Once that column is finished, the column crew moves along to build a column on the next completed footer. A third crew comes in and follows the first two crews, putting the caps on the columns as they are completed.
“We set it up as a process, so it goes a lot faster, and they become experts at it,” he said. “It’s a unique way of doing business. These guys are very efficient.”
Once one type of work is completed, those crew members are folded into other crews, though the now-former crew supervisor’s pay doesn’t change, Dowdell said.
Unfortunately, the bridge’s superstructure could not be approached in the same linear way, but rather had to bounce back and forth to different sections to not interrupt traffic, he said. They also couldn’t bring cranes under a power line, but had to build the materials out.
Workers started on land, built the middle part of the superstructure, then worked their way north, bouncing back and forth as necessary, Dowdell said.
They first had to build up, creating a bridge deck to provide a working surface (part of the third bridge itself) from which to expand, he said.
Creating the superstructure involved setting the girders, lining up everything and putting in bolts, putting in decking between the steel girders, welding the aluminum straps that the pans sit in, putting in rebar, and then pouring concrete, Dowdell said.
In addition to Clearwater, Fla.-based Case Atlantic Company, Russo Corporation of Birmingham, Ala., was used on the project for drill shafts, according to a subcontractor list provided by Dowdell.
Other subcontractors on the job include: Bessemer-based ABC Cutting Contractors of Alabama, for concrete grooving; Abramson LLC of Birmingham, for barrier walls; Alabama Traffic Systems Inc. of Fairfield, Ala, for signs, lights and barricades; Erosion Control & Environmental Supply of Auburn, Ala., for seeding, sod and silt fence; Gilley Construction Inc. of Manchester, Tenn., for reinforcing steel; Ground & Pipe Construction of Montgomery, for the navigation lights system; H&R Industrial Contractors, for structural steel erection; Ozark Striping Company Inc. of Ozark, Ala., for roadway striping; Pruett’s Painting Inc. of Millbrook, Ala., for structural steel and concrete painting; Wiregrass Construction Company of Ariton, Ala., and H&L Construction Inc.
Next Up for I-65
The next phase of the state’s continuing highway- and bridge-widening effort is scheduled to begin this month, ALDOT’s Harris said.
The nearly $80 million project will include constructing additional lanes on I-65 from the north end of the Catoma Creek Bridge to the south end of the Mill Street Bridge, and bridge widening on I-65 from north of Fairview Avenue to the Alabama River Bridge in Montgomery, according to information provided by Harris.
Brasfield & Gorrie LLC of Birmingham, Ala., won the contract for the 4.6 mi. (7.4 km) project with a low bid of $79.59 million.
The job will entail grading, drainage, pavement, concrete pavement rubblization, bridge widening, lighting, signing and signals.
The contract sets a completion deadline of Oct. 15, 2009, and includes an incentive/disincentive clause at certain phases of construction to minimize public impacts associated with ramp closures in summer 2008.
The project will result in six lanes for through-traffic from the south side of Montgomery to Prattville, Ala., replacing an aged, bumpy concrete roadbed and reducing congestion.
Another project to construct additional lanes from the Interstate 65/Interstate 85 interchange north to the Alabama River Bridge will complete the construction of a six-lane passage through the metro-Montgomery area, according to Harris.
The first phase of the main project will be widening and strengthening of the northbound shoulder, followed by widening and strengthening of the southbound shoulder, to allow traffic to be shifted away from the median for new lanes to be built toward the center of the existing roadway.
The new lanes will be divided by a concrete barrier, like the six lanes of I-65 from the Northern Boulevard to Prattville.
By next summer, traffic will be shifted to the new median lanes for crews to rubblize the existing concrete interstate roadbed and resurface with a new, smoother asphalt surface.
The resurfacing will begin with the northbound lanes, followed by the southbound lanes.
Bridge widening will be done throughout the project. The job calls for bridge widening from north of Fairview Avenue to the Alabama River Bridge, and new lanes and resurfacing from the north end of the Catoma Creek Bridge to the south end of the Mill Street Bridge.
Another project will create the new lanes from the Mill Street Bridge to the Alabama River Bridge.
Crews could be working around-the-clock during the length of the project, ALDOT said, and temporary nighttime and weekend lane closures will potentially be required in all phases of construction.
In addition, planned ramp closures during certain phases will affect the public’s ability to enter and exit I-65.
Harris said the two new through-traffic lanes on the Alabama River Bridge would see heavier use as other road- and bridge-widening work progresses.
“It was the cornerstone for the rest of this widening, and won’t be fully utilized until the rest of the widening is completed,” he said. CEG