Work on Interstate 520, Phase II of the Palmetto Parkway, has been under way in Aiken County and the city of North Augusta, S.C., since January 2007. Under the leadership of United Contractors Inc., many firms have combined their expertise to form “Team United” in a partnership to complete this design-build project.
The $152.4-million contract consists of the completion of I-520 from U.S. Route 1 to I-20 in a new location for approximately 6.5 mi. (10.4 km). Because of the connection to I-20, a multidirectional interchange will link the two interstates. The new roadway will be a controlled-access four-lane divided interstate.
The project also includes the construction of three interchanges and 13 bridge sites. Improvements to ramps will occur at the U.S. Route 25/I-20 interchanges, Clearwater Road, Ascauga Lake Road and various secondary and local roads to accommodate the alignment of I-520. A connector road will be built from U.S. Route 25 to I-520.
Additional items featured in the project include the construction of seven reinforced box culverts, two concrete retaining walls and 20 MSE walls.
The project is 85 percent complete, according to Jim Ewart, an owner of U.S. Constructors Inc. and its operations manager.
“We’re pretty far into the job,” he explained, “with all but one bridge complete.”
The one bridge that is still under construction is a new eight-lane bridge that is being built to replace two existing two-lane bridges; it is not actually on the Palmetto Parkway.
There have been additions to the original contract due to a $27-million change order that occurred about a year ago to include the rebuilding of the I-20 and U.S. Route 25 interchange, widening U.S. Route 25, and widening Clearwater Road from three to five lanes. Also, a paved 10-ft. (3 m) wide, 5-mi. (1.5 m) long bicycle and pedestrian path adjacent to I-520 was added.
Currently, the contractors have finished concrete paving on the mainline.
“We are building asphalt shoulders on the mainline,” said Ewart, “and putting finishing touches on the mainline.”
The travel lanes are concrete and 26-ft. (7.9 m) wide in each direction, and the shoulders are asphalt with an 8-ft. (2.4 m) outside shoulder and a 4-ft. (1.2 m) inside shoulder. According to Ewart, the South Carolina Department of Transportation (SCDOT) specifies that the mainline of I-520 is concrete, the side roads are all asphalt, and some of the ramps on the I-520 interchange are asphalt.
Ewart estimated that 200,000 sq. yd. (160,000 sq m) of concrete pavement and 220,000 tons (198,000 t) of asphalt pavement have been used on the project. Satterfield Construction Co., Greenwood, S.C., is the asphalt paving subcontractor and McCarthy Improvement Company, North Augusta, S.C., is the concrete paving subcontractor.
“We erected a RexCon Logo 12 portable concrete batch plant onsite to produce all the concrete for the roadway,” said Nick Wolf, project manager of McCarthy Improvement Company.
His company brought in numerous pieces of concrete paving equipment; for the mainline paving it used a Gomaco PS-2600 placer/spreader, a Gomaco TC-600 cure/tine machine, and a Guntert & Zimmerman SF850 Quadra concrete paver.
For paving of the ramps and acceleration and deceleration lanes the company used CMI MTP-4004 placer, a Gomaco TC-600 cure/tine machine and a Terex SF2204B HVW concrete paver.
“[The Terex SF204B] is a variable width concrete paver, which we used because the ramps were a lot of different widths and this prevented us from having to break the paver down and change the widths numerous times.”
A remarkable amount of excavation was performed on this project. Ewart estimated the number at about 5 million cu. yd. (3.8 million cu m). When moving earth for long hauls, articulated trucks like Cat D400s and D725s were used. For short hauls, Cat 631D scrapers were put to use.
Cat dozers are onsite for earthwork, “from new D6NLGP with GPS to D9Hs pushing 631s,” according to Ewart.
Support equipment consisted of Cat 12H and 140H graders, Cat CP and CS563 compactors, and Cat 815 compactors. Loader backhoes, mainly Cat 420DITs, and other loaders like Cat IT24s and Cat 950s were present on the job site. Additionally, many trackhoes were used, like Cat 320s and Cat 245s.
During a peak point on the project, stated Ewart, “there were 175 pieces of major equipment, Cat 420 and bigger, and 250 men working.”
The entire I-520 is about 23 mi. (36.8 km) long with approximately 15.5 mi. (24.8 km) in Georgia, which also is known as Bobby Jones Expressway, and 8 mi. (12.8 km) in South Carolina. It forms a loop around the Augusta and North Augusta Metropolitan area. In 2002, Phase I construction consisted of 2.5 mi. (4 km) of roadwork and construction of a bridge across the Savannah River.
When Phase II is finished, I-520 will better serve motorists by accommodating increased traffic volume that has been projected for the future. This is expected to lead to less congestion, fewer delays, and a safer roadway.
Bridges in the project have included the Clearwater Road bridge and the Ascauga Lake Road bridge. There also are the dual bridges of I-520 that cross Atomic Road. All of the bridges being constructed are made with concrete beams and concrete decks — excluding one. Due to the design and the degree of curvature of this one bridge, it had to be a steel beam bridge.
Bill Hedgpath, vice president of construction, United Contractors Inc., described the various cranes used for the bridgework. Two 150-ton (135 t) capacity Link Belt cranes, a LS238 H5 and a LS238 H, were utilized. Also on the job site were two 110-ton (99 t) capacity Link Belt cranes, a LS218 HSL and a LS218 II, and a Link Belt LS218 H with 100-ton (90 t) capacity. The contractor also brought in two American cranes, a 100-ton (90 t) 7260 and a 70-ton (63 t) 5300. Lastly, a 50-ton (45 t) Tadano TR 500 XL crane was on hand for the bridgework.
The Palmetto Parkway, Phase II project is being funded jointly by the city of North Augusta, Aiken County, SCDOT, the South Carolina Department of Transportation Infrastructure Bank (SCTIB), and the Federal Highway Administration.
Team United will manage the project from start to finish to achieve complete construction of Phase II. The Team United partnership includes local firms such as U.S. Constructors Inc., which has already teamed up with United Contractors to work on a separate I-520 contract that is presently under way in Georgia. In addition to managing the Palmetto Parkway contract, United Contractors is the primary bridge building contractor, and U.S. Constructors is the roadway contractor.
Additional companies that are part of the team are R.E. Goodson, performing heavy earthwork; Triplett-King & Associates Inc., performing the bridge design; and Florence & Hutcheson Inc., performing the roadway design. The team has utility coordination by Coleman-Snow Consultants Inc., and soil testing by F&ME Consultants Inc. Other members of the team are S&F Engineering Inc., Palmetto Safety Solutions Inc. and Public Strategy LLC. CEG