Not Just "Big Guys" Benefit

Contractor anticipates quick payback on high-speed GNSS grade control system

Small grading and excavation contractors who get sticker shock when thinking about adopting stakeless, stringless grade control ought to consider the experience of Scott Petry. The president of Greenfield, Ind.-based Petry Excavating purchased such a system in mid-2013 and immediately got an idea of how quickly it would pay for itself. A couple of years ought to sound pretty good to anyone.

In late summer, Petry, his son and another machine operator showed up in Lafayette, Ind., with a new Deere 700K XLT that Petry had purchased to grade a 15-acre site of a new distribution hub facility. The machine came equipped with a Topcon Positioning Systems 3D-MC2 high-speed automated grade control system.

Petry was counting on the equipment to cut and fill about 30,000 cubic yards of dirt to allow construction of a pad for the 55,000-square-foot facility, a parking area, a trench for electric conduit and a drainage swale, in addition to other work—excavating several holes for the building pads and backfilling them with gravel.

The original site topography did not have widely varying grades, but Petry Excavating and the general contractor, Indianapolis-based Commercial Team Construction (CTC), still benefited from the use of the grading technology. Dozer operators transferred material short distances and did not face any high cuts or deep fills, for the most part.

All told, Petry expected to have all of the grading, excavating and backfilling for the project completed in a few days. Two days earlier, Petry Excavating dug footings and backfilled them with gravel. By the end of the day, Petry anticipated that the parking area and remainder of the site would be graded to specifications. A few days later, excavations would be made for sanitary and storm sewer and Petry Excavating would be finished on the project until several weeks later, when final building pad backfilling would be required.

"We're small—six to eight employees," Petry said of his company, which specializes in commercial work. "Typically, if we were putting in a fill like this and grading, we'd have two or three laborers out checking grade," but his viewing the elevation on a monitor in the cab and having a worker occasionally double-check it after a pass eliminated the need for staking and stringlining on this project, for the most part.

Petry admitted that convincing him to adopt the system was a tall order, simply because the investment was considerable. He saw GPS-enabled grade control in use on large highway projects, but never on smaller jobs like Lafayette. "I didn't think we'd ever do it," he said, noting that CTC—which specializes in commercial buildings—had numerous projects in its pipeline and he anticipated plenty of future partnering opportunities. Joel Fritz, Joel Fritz, CTC president, "likes the grading technology because he's not spending $4,000, $5,000 on staking and engineering, so the system has been a selling point for us," Petry said.

The Topcon system purchase was the first exposure to automated grade control for Petry Excavating, which generates typical annual revenues of $1.5 million. "Truthfully, I thought it was out of our price range, but I think that for this project alone, it'll probably give us a $15,000–$20,000 savings; I really believe that," Petry said. "With fuel at $4 a gallon, you can't afford to go over the same row two or three times.

"It all boils down to efficiency," Petry continued. "What do I have that the other guys don't? "It's efficiency, which is quality when you're done."

Taking the plunge

Five weeks prior to starting work at the distribution hub facility, Petry purchased the new dozer. Soon he got it wired with the grade control system, which also can be installed on Deere dozers at the factory. The system is different from others that Petry had heard about.

The 3D-MC² system is an evolution of machine-control technology that broke the last barrier to productivity: speed. System components include an MC-R3 GNSS controller that works in conjunction with multiple sensors; a touchscreen, GX-60 control box; and a conventional GNSS antenna mounted on the dozer blade. The MC2 sensor combines three electronic gyroscopes and three inertial measurement sensors to measure the X, Y and Z position as well as the roll, pitch, yaw and acceleration of the dozer blade.

The technology gives the system the capability to provide blade position readings up to 100 times per second—or roughly five times that of conventional systems. Additionally, extensive testing and jobsite data indicate that the system yields about three times the grading smoothness of other machine-control systems.

"I wasn't even really looking to [adopt] it, to tell you the truth," Petry said, but Joel Frost, regional sales manager for construction machine control products at Topcon—someone whom he has known for a long time—convinced him to do it. "He kept saying I'd go to it one day and I kept telling him, 'No way. It's a lot of money,'" Petry said.

"Well, I got this new dozer and he met me one day and told me that I really ought to put the system on and just try it. It took about two days to tell myself that I really had to have this thing. I could see the efficiency right off the bat."

When Petry has needed changes to the three-dimensional digital terrain model viewed on the GX-60 monitor in the cab, he provides the model builder, WSI Engineering, Plainfield, Ind., with the change. WSI Engineering has changed the file and emailed it to Petry, who transfers it to a flash drive. Brian Kitchens, construction sales representative at Positioning Solutions Company in Indianapolis—which sells and rents construction, GIS, survey and engineering technology solutions—loads the file onto the system on the dozer.

Just after Petry Excavating bought the new dozer, it prepared a large parking lot subgrade. Petry estimated that it took a three-man staking crew four and a half days to finish. "I honestly think I could have finish graded in a day, day and a half with this system and saved maybe $4,500 in labor in one project."

Petry credits the system for allowing him to acquire the backfill work on the Lafayette project. "CTC laid out its geogrid and asked us if we would lay their stone for them and in 20 minutes, it was to grade," he said. This was a win-win; Petry Excavating generated more revenue and CTC got the work done more quickly than calling a crew up from Indianapolis and maintained its profit margin on the work.

Only a handful of stakes were visible on the site. Without the grade control system that Petry Excavating used, a crew would have been needed to pound stakes with rough marks into rows in the parking lot, and then pound stakes with final grade marks into it after the dozer finished rough grading. "That's just the way it's been done for years," Petry said. "You've got to worry about stakes getting hit."

Major impact

"Efficiency is the biggest thing I've seen from the system," Petry said. "It's accurate—the quicker I get in and out of a jobsite, the more money I make. I can see this system paying for itself in two or three years—it's a pretty cheap investment when you look at it that way. I could have done this job 100 percent stakeless," he said, referring to a few stakes that were set for the concrete footings. To occasionally check grade following a pass, Petry or equipment operator Terry Goff used a 226-channel Topcon HiPer V receiver and FC-250 field controller mounted on a pole. "Right now, everything we've graded is within an inch, which is my tolerance—I'm happy with that," Petry said.

Goff credited Positioning Solutions and Kitchens for helping him get over a short learning curve with the grading system. "This system helps me to see the slope and elevation wherever I am; it helps me to get the bigger picture. If you do run over a stake, you know where you are. With this building pad and parking lot, it's probably saved us a week, week and a half of time on this project."

Petry agreed that the system is easy to learn. He recalled having his son, who graduated from college after the Fall 2012 semester, rough-cut about three feet from the parking area despite his son's complete lack of experience with the system. Over the phone, Petry explained how to get the system up and running.

"It's not like it was when profit margins were 16–18 percent—you're talking about of 4–6 percent. Efficiency is everything. I think the other thing that this will save in the long run is machine wear. A set of tracks is $10,000, and I might be extending its life by 10 or 20 percent if I'm going over the surface with a minimum amount of passes."

Petry indicated that adopting automated grade control is a choice now, but it won't be for long. He recalled using laser levels, then transits and stringlines, then pipe lasers. After trying all of these tools, he had to have all of them. "I think 3D GPS technology is just the next step," he said. "I think 10 years from now, every small contractor will have it if they want to stay competitive. The economy hurt a lot of guys in the past four years and I see fewer companies bidding for work. I think everyone will have this technology soon. The profit margin has gotten smaller, so efficiency is everything now."

[ Back ]

deliciousrssnewsletterlinkedinfacebooktwitter