Finish Grading Time Cut in Half

A popular cowboy song, "Cattle Call" written by Tex Owens, was made famous by Eddy Arnold in 1934. A couple of decades later, the song title was adopted for a rodeo and community celebration that placed Brawley, California on the map. Located in southeastern California about 125 miles east of San Diego and 30 miles north of the Mexican border, Brawley is also the location of a four-acre site prep project for the Manzanilla Terrace Apartments. Roxwell Construction, Inc., based in Thousand Palms, California, is currently engaged in completing the project. Roxwell’s use of GPS grade control is enabling them to deliver the precision and productivity typically associated with larger contractors and larger projects.

"We’ll be moving about 60,000 cubic yards of silty clay to prep the site for several three-story apartment buildings, a club house, swimming pool and parking lots," said Roxwell Fontenot, president of Roxwell Construction. Manzanilla Terrace Apartments will have 113 units when completed on a site squeezed into a mature residential neighborhood.

"What makes the site a bit challenging is the amount of over-excavating needed for the sub-surface drainage system located under the parking lots," Fontenot says. "It’s four-feet deep and needs to be perfect, since they’ll be installing a new, high-performance porous asphalt surface over the engineered fill we’ll be using."

Rainwater will drain through the pervious asphalt and a mix of imported soil, sand, and gravel below. It then drains to the edges and is delivered to the storm sewer through a catch basin.

"Because land is so expensive in California, the developer is using this new system rather than open-air retention ponds that can take up acres" states Fontenot. "With the collection system located underneath the parking lot, the project engineers are making the space do double duty."

Ahead of schedule due to GPS

Roxwell’s six-person crew is well ahead of schedule on this four-month project. "We’re completing our finish grading in half the time because we’re using GPS machine control," reports Charlie Hollingsworth, site manager and machine operator for Roxwell Construction. The company has a new Cat D4K Track-type Tractor equipped with a Trimble GCS900 Grade Control System. It ties into a Trimble SPS780 Smart GPS Antenna, that serves as the base station. "We had completed a major part of the job and the grading was dead on, but the developer had discovered a mistake in the site plans. So, we simply loaded the updated design onto the machine and re-graded the site to the new specs in one day!"

Roxwell has been their new GPS grade control for about four months. "The Trimble system is easy to learn," states Hollingsworth. "I don’t ever have to stop my machine, climb out, and check my grade. I can set the blade down and know where I’m located at all times — that saves a lot of time in a workday. As long as I’m in the machine, I don’t need a grade checker working beside me or have to stop to set up grade-check lasers."

Fontenot adds that the Cat D4K with the Trimble GCS900 Grade Control System is at least twice as fast as grade checking with lasers. "Plus, every time you set the laser up; there’s a chance the calculations can be off."

Trimble technology helps company

Roxwell Construction has been around since 1995, although Fontenot has been involved in construction for about 30 years. "My company was strictly a golf course construction firm until about three-and-a-half years ago when we shifted the focus to commercial work — principally, shopping centers, warehouses, and residential developments," Fontenot says. "The company has quadrupled in size in the past three years."

Even though it’s been a relatively brief time since Roxwell acquired the Trimble construction technology, it has enabled the company to successfully bid on more complex projects and compete on bids where GPS grade control is required. "We’re experiencing time savings and greater productivity by virtue of the fact that our work is so accurate with one pass that we’ve eliminated rework," states Fontenot. "Plus, we save money by not having to pay for grade checkers."

"The Trimble system began paying dividends from day one. On our first job, I learned how accurate we can be with just one pass. The developer came out and checked our grade and we were within 1/10th on every one of the 74 shots they made."

The bigger picture was also a key consideration. "GPS machine control is the way of the future and I felt that if we didn’t jump in now, we’d be that much further behind," Fontenot says. "You know what one of the most important things about GPS technology is what it says about your company and its capabilities. When we arrive on a jobsite and the owner sees the dual masts on our dozer, they know the job will be done accurately and that we know what we’re doing — it sends the message that we’re not a small-time operator."