GPS Machine Control Curbs Costs on Huge Residential Subdivision

Toronto-based Mattamy Homes is building a high end planned community in Oakville, Ontario, and TACC Construction, Ltd. will do the work to prepare the 800-acre site for home building and the finished paving of the network of roads.

“We’re completing all the site development earthworks, underground and all roadwork for this project,” stated Frank Saracino, road superintendent for TACC Construction. “We have seven weeks to complete our portion of the project.”

With the tight timetable, TACC relied on technology to ensure its productivity on the project. The company has been using GPS machine control on its earthmoving machines since 2008, but this was its first experience using the technology on its slipform concrete curb and gutter paver.

“The technology is incredibly fast and accurate so it helped us achieve grade tolerances without the dependence on survey crews pounding stakes everywhere,” said Saracino.

To level and balance the site and strip the topsoil, TACC used Caterpillar 621 scrapers and the Cat dozers equipped with machine control.

“What was new for us was using Topcon Millimeter GPS machine control on our Power Curber 5700-C,” Saracino said. “We like the Power Curber because its compact and designed for tight radius jobs, which made it appropriate for the subdivision with its meandering roads and cul-de-sacs. It was pretty amazing to see how efficient the Millimeter GPS Topcon system made the curber. We eliminated stringlines which saved us time, labor, concrete waste and it’s much more precise. The technology made the Power Curber at least one and a half to two times quicker than using traditional methods.”

There was six miles of curbs throughout the development that TACC carved out and fine graded them with 3/4-inch stone as prep for the asphalt paver and placed the concrete curb and gutter using its Power Curber 5700-C with Topcon Millimeter GPS machine control.

There were three mobilizations on this project as far as the curb and gutter work. DiCrete Construction first laid a gutter footing or base stage which was 20-inches wide and 6-inches thick. There are two rebars placed in the base.

The next two mobilizations were two stages of the 20-inch curb. Initially 9-inches of the curb are placed with the gutter base. After the road asphalt is paved the Power Curber comes back and places an 8-inch cap on the curb to finish it off to a proper height.

The curb and gutter work follows The Ontario Provincial Standards for Roads and Public Works (OPS), matching the 600.04 specs for curb and 600.07 specs for where the curb and gutter meet.

TACC used 45,000 metric tons of base stone on the project and a total of 65,000 metric tons of stone was used throughout the project. The soil on the site was a mix of clay and shale which was pretty weather resistant. As Saracino said, “It could rain one day and we’d be back working on the site the next day.”

Mattamy Homes hired its own engineering firm to create the original site plan that TACC adapted for use with the Topcon GPS machine control systems by creating their own 3D digital model. Both the earthmoving machines and the slipform paver used the same site model.

“Because our curb machine runs so efficiently and accurately with the technology we’ve literally experienced a 10 percent savings in our concrete use,” stated Angelo DiGravino, general manager for DiCrete Construction Ltd. “The Power Curber with the Topcon technology is running so fast we recently broke a production record of ours - we poured 3.5 miles in one day, which shows how proficient we’ve become in using the system.”

TACC Construction faced three production deadlines with this project.

“We beat each deadline by two to three days, which is pretty impressive considering how tight the deadlines were,” Saracino said. “This was our first project where we were totally integrated with technology on our earthmoving and road construction. The technology provided seamless transition from task to task.”

“We were given a tight timeline and achieved it. The project owner is happy with the time lines and quality of our work. If they’re happy… we’re happy. It’s as simple as that,” DiGravino said.

Jeff Winke is a business and construction writer based in Milwaukee, Wis. He can be reached through