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Sloan Construction Uses GPS to Reduce Costs at S.C. 161 Job

Thu February 15, 2007 - Southeast Edition
Gwenyth Laird Pernie



Construction costs are reduced in the widening of 4.8 mi. (7.7 km) of S.C. 161 in York County, S.C., with the usage of Topcon high global positioning systems (GPS).

General contractor for the $11.9 million project is Sloan Construction Company (Upstate Region) of Duncan, S.C. Project managers of Sloan Construction are Mickey O’Shields and Joseph Fowler.

According to O’Shields, this was the first time Sloan used the Topcon global positioning systems.

The global positioning systems are 29 active satellites (as of August 2006) that orbit the earth, transmitting radio signals to GPS receivers.

According to O’Shields, Sloan is using the GPS systems for surveying and fine grading of the S.C. 161 project

“For surveying, Sloan is using a Topcon System 5 with a FC-100 data collector,” O’Shields said. “For fine grading, Sloan is using a Topcon System 5 with machine control. This GPS is mounted on a Caterpillar D5G dozer and Komatsu GD 555 motorgrader.”

According to O’Shields, the biggest advantage of the GPS systems has been a reduction in overall construction costs.

“Using the GPS system for surveying has reduced our re-staking cost; in addition, because we are not totally dependent on an outside surveyor, it has allowed us to get quicker results,” O’Shields said. “Utilizing the GPS system in fine grading has reduced our labor cost by removing the manual grade checking process which is repetitive and costly.”

Widening of S.C.

161 Long Overdue

According to Jason Johnston, district construction engineer with the South Carolina Department of Transportation (SCDOT), York County is one of the top growing counties in South Carolina.

“S.C. 161 has been maintained and repaved on a rotating cycle, so it is in good condition. However, road improvements are actually 10 years behind traffic needs in the county,” Johnston said. “S.C. 161 has been carrying four lanes of traffic on two lanes for years.”

Funding for the widening of S.C. 161 is coming entirely from a York County sales tax.

The widening of S.C. 161 will expand the road from two to five lanes, with a two-way turning lane running the entire stretch of the project. The project includes one bridge built over a small creek crossing, installation of curb and gutter, storm drainage and excavation.

According to O’Shields, the centerline will be moved slightly in most areas.

“Additional lanes will be constructed on one side of the centerline at a time and slightly elevated above the existing road,” explained O’Shields. “The existing road will be used as a base for two of the five lanes.”

Site Preparation

According to Johnston, before the project could begin, the SCDOT was responsible for removing an old gas station, which involved the disposal of four underground storage tanks.

Sloan will do all grading work.

According to O’Shields, some cut and fill was required for the widening.

“A total of 80,000 [cu.] yards of borrow material and 20,000 cubic yards of on-site material were required to balance the terrain,” O’Shields said.

Additional site preparation included installation of approximately 33,000 linear ft. (10,000 m) of drainage pipe, which ran underneath each side of the road. Drainage work was handled by CK Contracting Inc. of Kings Mountain, N.C. Single lights were redone at one intersection; Sloan subcontracted Walker Brothers Inc. of Lexington, S.C., for this work.

Sloan owns and will operate all equipment used in the paving portion of the project. Paving equipment includes Blaw Knox rubber-tired and track pavers and Ingersoll Rand rubber-tired and smooth-drum rollers.

Asphalt was processed at the Sloan plant in Blacksburg, S.C. Approximately 80,000 tons (72,600 t) of asphalt will be used on the project.

According to O’Shields this has been a straightforward project.

“With the exceptions of the learning curve required in utilizing the GPS system, the project has moved along without any unexpected challenges,” O’Shields said.

Widening of S.C. 161 began in October 2006 and expected to be complete by June 2008. CEG