A monolithic application using a Power Curber 8700 multi-purpose slipformer is expected to save more than half a million dollars on a NC Department of Transportation highway project near Asheville, NC.
In addition to the savings, the application is eliminating many of the expected traffic closures, a headache for vacationing drivers in the Blue Ridge Mountains.
“Previously, 10 bridge decks were replaced on the same stretch of highway,” said Tom Dorsey, chief estimator for APAC of Asheville, the company that recently won the contract for the traffic island paving. “That took two years and the public was sick and tired of lane closures. They hated to see orange barrels anywhere.”
The current island project involves 13 mi. (20.9 km) of work on U.S. 23/74. This includes 20,000 ft. (6,100 m) of replacement concrete work, 16,000 ft. (4,880 m) of which can be poured by machine. The remaining 4,000 ft. (1,220 m) is too narrow, located in areas where the median tapers for left-hand traffic turns.
Dorsey came up with the idea of the monolithic pour and presented it to DOT engineers under the state’s Value Engineering Proposal.
“This means that if you can show DOT a better way, after you’ve been the low bidder, it boils down to the contractor gets half the savings,” said Dorsey. “This is a good thing for APAC.”
The pour eliminated 60,000 ft. (18,300 m) of curb and gutter. The application, involving curb and gutter on both sides of an 11-ft. (3.3 m) traffic island, replaces a 17-year-old concrete island. APAC used a milling machine in front of the Power Curber 8700 to cut off the old island flush with the existing pavement.
“The road had been re-paved several times which had about taken away the gutter,” said Dorsey.
Originally, the project was designed to remove about 3 in. (7.6 cm) of the asphalt to expose the gutter. The process of taking up old asphalt and leaving a 3- to 4-in. drop (7.6 to 10 cm) in the road would have resulted in big-time traffic closures. “Not having to close for traffic for six months was as big a seller [to the state] as the money,” Dorsey said.
Ron Watson, DOT division engineer, like the idea that the traffic could continue to flow, as well as the tremendous savings. “We were able to do the work without a drop-off,” he said. “Even after the milling was done, we could let traffic run. Doing it this way, it’s closing a shorter stretch of the road at a time. On Memorial Day weekend, we were able to drive the machine off the road and open up the road for holiday traffic. We couldn’t have done it the other way.”
Under the original proposal, the old gutter would have remained while 18-in. (45.7 cm) curb and gutter was poured on top of the existing gutter on both sides of the island. Then, a screed would have been used to fill in the center with concrete.
APAC planned to complete the project in two months time, as opposed to six under the original plan.
APAC’s dealer, Southern Equipment Service of Salisbury, NC, worked with APAC, and the mold was engineered and built at the Power Curbers factory.
This island with sloping curbs is 12 ft. (3.66 m) wide and has a .25-in. (.63 cm) fall from the center to keep water from ponding on it, according to David Webb, APAC’s project manager. Stringline guides the machine both vertically and horizontally.
One concern early in the project was elevation changes as the machine maneuvered through a curve. The slope on elevation is 2.3 percent. Eddie Lanter, service manager for Southern Equipment Service, worked with the crew on this part of the project. “Eddie was very knowledgeable and very helpful,” said Dorsey.
(The preceding article appears courtesy of Power Curber Profiles.)
Today's top stories
