With a little extra thought, a Georgia contractor saved the state’s taxpayers $10 million.
Before The Scruggs Company of Valdosta began working on the 9-mi. stretch of Interstate 75 from Adel south to the Lowndes County line, it proposed a plan that would implement “value engineering.”
The plan, which was approved by the Georgia Department of Transportation, changed the phasing of the project to move all four lanes of traffic onto the southbound side of the highway and work on the northbound side first.
The $10 million savings on what became an $82 million project comes from the reduction in the amount of temporary pavement, temporary barriers and earthwork. A job that initially called for 350,000 tons (318,000 t) of asphalt will now use only 150,000 tons (136,000 t).
The new phasing process was made easier when Scruggs also won the $17.7 million contract to replace the superstructure of a bridge over I-75. This work was subbed out to Southern Concrete.
Work on this stretch of I-75 began in November 2004. It is on-schedule at the 45 percent mark and is expected to be complete in August 2007.
While the order in which the work is being completed changed, the specs did not. Workers are performing a full-depth concrete replacement along the highway and three interchanges. It is part of GDOT’s effort to widen 85 miles of I-75 from four to six lanes. Of the 10 projects in the initiative, two are open to traffic, four are under construction, two were let June 9 and the remaining two are scheduled for the December letting. Some stretches of the highway are 40 to 45 years old and have only seen routine maintenance to the slabs, said GDOT District Construction Engineer Joseph Cowan.
The Scruggs contract is the first full-depth replacement in the state, as well as the first to use contraflow staging. All sections of I-75 from Tifton to Lowndes County and north of Cordele will be completely replaced.
The new roadway consists of 12 in. (30 cm) of GAB, 3 in. (7.6 cm) of asphalt (placed by Scruggs’ asphalt division) and 12 in. (30 cm) of concrete. The GAB and asphalt layers are 54 ft. (16.5 m) wide, while the concrete is 50 ft. (15.2 m) wide. Scruggs crews also are placing two 13 ft. (4 m) inside shoulders. All of that roadway will call for 240,000 cu. yds. (183,000 cu m) of concrete; 500,000 tons (454,000 t) of GAB; 150,000 tons (136,000 t) of asphalt; and 400,000 cu. yds. (306,000 cu m) of earthmoving.
A good portion of the material will seem familiar to the earth below. Approximately 45 percent of the GAB is made from the old concrete roadway. It was recycled by Mullinicks of Jacksonville, FL, one of approximately a dozen subcontractors.
GDOT’s Cowan said concrete “makes for outstanding aggregate base.”
John Romaine, operations manager of Scruggs’ concrete division, said the work hasn’t offered up too many challenges along the way.
However, his crews are getting ready to push its equipment to extremes. Romaine plans to place all 36 ft. (11 m) of southbound lanes at once with the company’s Gomaco 2800 slipform paver. The machine maxes out at 37.5 ft (11.4 m).
But as Romaine discusses the upcoming task from the Adel site office, he exudes a confidence in the machine and his operators. It’s a task he’s successfully been a part of before – he placed 37.5 ft.-wide slabs of concrete at the Orlando International Airport.
The real trick, he said, is keeping up with the feet per minute. To do so, crews will run 12-yd. (9 cu m) batches of concrete from the temporary plant next to the site office to the road, instead of the 8-yd. (6 cu m) batches they are currently running.
During the first part of the project, crews were placing a 24-ft. (7.3 m) wide mainline with the slipform paver.
While the majority of the work along I-75 is concrete related, Scruggs’ asphalt division was hard at work, too. They place the figurative bologna in a concrete sandwich with a Blaw-Knox PF-3200 and Ingersoll Rand DD90 and DD91 compaction rollers. The machines are being fed by 16 Peterbilt dump trucks, which load up at the asphalt plant in Lenox.
But that’s the only asphalt work there is. Not even the temporary roads along this project are asphalt. It is the first time in Georgia’s history concrete paving is being used on a temporary basis.
Romaine said this project could help diffuse some sterotypes of concrete roads. He said his crews are ahead of schedule, proving that the process isn’t always slower than asphalt.
The I-75 project is one of only a couple of active projects in Georgia using the Advanced Speed Information System (ASIS), which displays electronic messages to drivers in real time. Romaine said the system senses the speed and amount of traffic flowing through the work zone and sets speed limits and displays warnings as needed. Scruggs crews also can set the system to announce a vehicle accident should that happen.
It also is the first GDOT project to allow the use of any NCHRP350 test level 3 traffic barriers. The ones chosen by The Scruggs Company are longer and narrower (by 6 in.) than the Georgia Standard Barrier, which means handling costs are less and there’s more room for drivers going through the site. CEG
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