Photo: Montana Laser

Blade control: You’ll be surprised what contractors are saying.

By Penelope Grenoble O’Malley

You go to the shows, you demo the systems, and they look great. But what happens when you get home? Contractors talk about what they’ve got and what they’re doing with it.

By common agreement, factors that can influence blade control performance and cost savings include the type and size of jobs you do, tolerances you’re expected to meet, regulatory agencies you have to deal with, and operator expectations and resources for plan conversion and model building, plus technological coordination.

“GPS is a risk,” says Todd Moyer, surveyor and GPS (global positioning system) coordinator for Independence Excavating Inc. in Independence, OH. “But it’s a good risk, because if it works properly for you, it will pay itself off.” Independence Excavating bought its first system three years ago and continues to work closely with its dealer, Ohio-based Precision Laser and Instrument Inc., to get the most from what it’s got.

Moyer estimates that right now the company has 15 SiteVision systems and four Trimble GPS 9000 systems, plus four Blade Pro 380s with the ATS Total Station option. “We use the total station setup for accuracy,” says Moyer. “In airport work we have a 300 tolerance plus or minus, which is less than half an inch, and we have very easily obtained that accuracy with the ATS and Blade Pro 3D. We have four graders set up with automatic systems, including a 140 H, 14 H, 16 H, and 16 G. We’re redoing the airport on an air base in West Virginia, and both graders are running at the same time. The 16 G starts our subgrade, and then our 140 H does our sub-base, our stone requirements.

“We stick with the GPS where our tolerance is plus or minus a tenth of a foot. Anything under that, we’ll get it to grade, and then the graders go through to tighten up the tolerances. But we don’t tend to use the GPS on the graders so much anymore now that we’ve discovered Trimble’s Total Station setup, which gives a tenth tolerance, in fact under 500th tolerance.

“Survey control is the basis of anything we do. When I calibrate job sites, I have surveyors come in and tighten up the control and the benchmarks in elevation so when I do my calibration, everything is as accurate as possible. The more points you have when you calibrate a site, the better. The same thing with building the 3D models. If I spend an extra day concentrating on making sure a site is as accurate as possible, it saves downtime in not having to come out and fix the machines in the field or go back and redo the 3D design. Prep time and being as accurate as possible at the beginning of the job will save you from two to three times as much at the end.”

Independence Excavating has GPS on 18 dozers ranging from a DC-10 to D8s, D7s, D6s, a D5, and 650s. Only three of the dozers have automatic machine control. The graders have automatic systems, and Moyer says “it’s foolish not to. But I’m not sold on having the automatics on the dozers. I like having the operators do what they do. One thing we do that’s unusual is the GPS on the D10 is mounted on top of the cab. It’s such a rugged machine that we were afraid it would break the equipment. We’ve calibrated the machine so when it’s sitting level, the front of the track where it rolls down to the nose is actually where the system reads grade from, and guys have no problem with that.”

Photo:Leica

GPS-equipped dozers get your fine grading done—sometimes to within 0.25 inch.

“Had we not had the machine control,” says Branas, “we would never have been able to complete a lot of these projects on schedule.” The company uses SiteVision, and in the past had used Blade Pro 3D for the same reason as Moyer—the quarter-inch accuracy—but has eliminated it now that Trimble has added the option to its SiteVision system. As far as setup goes, Branas cautions that good radio coverage from the base station is essential. “In most situations you don’t need repeaters. But when you do you’ve got to be careful how you program them. The radios all talk to each other, and they know who each one is. So if you put repeater 1 an inch farther away from the base than repeater 2, you’re going to get more latency and it will affect the quality of your position.”

Branas also recommends that a prerequisite for using these systems well is to have “a competent person who understands technology and can effectively manage an organization with more than one or two machines. Even with one or two machines you’re going to rely really heavily on the dealer for a while and you’re going to inevitably have to hire a person to manage the system.” (Phillips and Jordan’s dealer is Southern Laser in Lutz, FL.)

Asked where his savings come from, Branas says it’s difficult to identify conclusively because situations vary. He knows without doubt, however, that a system can pay for itself in one job, and sometimes “not even halfway through a job.”

“Doing sports fields it’s critical that we have the dual-slope laser setup. Basically I take that football field right down the middle both ways and cut it into four pieces of pie. The dual slope laser allows me to get both angles of slope in one piece of that pie all at one time.

“The biggest factor, whether you’re roughing or fine finishing, is having a good benchmark that you can come back to every day. On baseball fields, I use home plate; on soccer fields or football fields I use the very center of the field where they kick off.”

Todd says the optional auto/manual switch he selected is also critical. “There are times and places when you need to get out of automatic control to feather in or daylight out areas. The switch is very important because I don’t have to stop the tractor. As I’m rolling, I just hit the button, which means you never see a grade change or any kind of change in the dirt.”

Where do the savings come from? “There’s a labor savings, most definitely, plus a fuel savings and also a material savings, which is one of the reasons this was an easy sell. We have an in-house concrete company that does building pads. Typically we’d have a half to a full load extra brought out. But with this equipment,” Todd says, “we get the dozer set up and get the benchmark, and as the dozer is blading it out, it’s putting it to the exact grade so the trucks are dumping exactly the dirt we need.”

“Obviously you’ve got to know to exactly where you’re grading and where you’re pitching and verify that this is correct. We’ll do it manually initially so we know exactly where our tolerances are, and then we hook up the machine, hook the blade control on, and verify it at each end. Once we know we’ve got it, we go. It saves one man, and I would say it paid for itself in three to four jobs.”

GPS Keeps the Nation’s Oldest Contracting Company Up With the Youngsters
Todd Gokey is project engineer for Barrett Paving Materials Inc., the oldest contractor in the nation, established in 1864. Today the Syracuse, NY, division he works for does airport and highway reconstruction work, and for the past three months Gokey has been working with Leica GPS indicate systems on two dozers and an automatic system on a Cat G12 motor grader. Typically, operators are expected to meet tolerances of plus or minus 6 millimeters—one-quarter of an inch.

“One of our motivations for GPS,” says Gokey, “was that New York State DOT [Department of Transportation] has set up a spider [RTK] network with their own base stations. Their intent is that their inspectors will use rovers, and they have announced they’re going to change the spec books to accommodate automated machinery. The specifications on a recent job included that the contractor had to buy the state a base station and a couple of rovers.

“The way we’re set up now, we use the rover for all our survey work, including drainage structures, pipes, and the center line for the pavers. The excavator does the bulk of the work, and the dozer comes behind and gets the fine grade done. Leica just came out with a 3D system for excavators, and I’m looking into that. If we had GPS on the excavator, the operator would know exactly what he’s digging and where. And with a system on an excavator, the dozer and excavator would almost be a standalone crew.”

“We’ve always tried to stay on the front end of technology,” says Mathiowetz, “and we were convinced this was coming. We went with one unit on an ATV to start with, just to see how it would work. And that was successful so then we just kept going. We use it on the graders for fine grading, which has worked well on our private jobs, but DOT is telling us to start tightening down. They want within half an inch and most of the GPS’s right now are within a tenth. So we have that half an inch we’re arguing about all the time. What typically happens is we go to manual and get it.

“With GPS our biggest problem comes in when we go to vertical curves. Anytime the road starts changing rapidly the GPS doesn’t keep up. So we also find ourselves doing vertical curves and steep horizontal curves by hand.”

“There’s a lot of paraphernalia associated with GPS equipment,” says Kenny Liefeld, “so when you can go into the job, put the computer into the cab, hit grade, and go to work, it’s awesome.”

Liefeld Contracting Inc. does heavy highway work, commercial sitework, and an occasional subdivision. Currently it has three machines out of an inventory of 130 that are GPS-equipped. These include automated systems on a Caterpillar D 6N dozer and a 143 Caterpillar motor grader and an indicate system on a John Deere 450 excavator. They’ve been using the system on the dozer for two years, a year on the grader, and only a few months on the excavator. A rover rough stakes the jobs.

“Before GPS,” says Liefeld, “we used lasers. And in fact, the motor grader and the dozer and the excavator all have 2D systems. I use the 2D to calculate where the blade is and the GPS to tell the machine where it’s at on the job site. We’ll rough grade a building pad with GPS, which is where I think it really shines. We move the dirt only once and can get within a couple of tenths versus a couple of feet. Then we set the laser up.

“For something like a retention basin, we use the excavator to cut it out as close to grade as we can. Then we follow behind with the automated dozer, which clips it and gets it on grade. Then we use the motor grader to get to fine grade.

“If it was up to me, if money was no object and things were going well enough that we felt comfortable that we would go headfirst into this, we would probably have at least one pan [scraper] indicator system and probably use a D8 with an indicator system to rough a cut, and a D6 would run the fill. That way, the job is full of GPS and everybody knows what’s going on.”

One of the factors that would make Liefeld feel more comfortable is having a good model to go by. “When you have a good model, everybody is working off the same information, but the biggest hurdle is getting the digital file, creating the model in a timely fashion, and getting it out in the field. Machines do what they’re told to do very well. If you tell a machine to do something wrong, it will do it exactly wrong.”

At Mathiowetz Construction, Brian Mathiowetz echoes a lot of contractors about models and file conversion. “The onsite stuff is simple. The guys out there have got that figured out. Set your base station up and get going. The difficult part of working with GPS is when the file they give us is loaded with errors and we have to start cleaning it before we can work with it.

“You ask the engineer if he looked at the whole file after he tweaked the controls in one corner. Did he see how what he did impacted the other parking lot? And he won’t have done that. We get a plan on Monday, and then we might get a different one on Tuesday and a different one on Friday. How do I know what’s changed? We’re probably going to have to hire more people to check plans, which is effectively working against the cost savings these systems are supposed to generate.”

Close Enough for Utilities
In Huntsville, AL, Stanley Construction Co. Inc. owns two base stations, but if a job is in range it uses a cooperative base station managed by the state at NASA’s Marshall Space Flight Center. The company does mostly commercial site prep and road building plus mass grading for subdivisions. Stanley Construction has been using Topcon control systems since 2002, one automatic system and two indicate systems, all on dozers. Motor graders are not equipped, in part, says Vice President of Project Management Al Stanley, because they’re used mostly for mass grading before the utilities go in. “Our tolerances are plus or minus a tenth, which is close enough for utilities, and we’re able to get that without a problem with our dozers.

“We use the automatic more for rough grading and finish in manual mode. Our first system was automatic, and it wasn’t what I thought it needed to be after the calibrations to really use it for finish work. We were never able to get the valves to respond quick enough to where the tolerances would be there on the nose. The second machine we equipped with indicate only, and the third one I went back to automatic because I anticipated running it a lot myself and I wanted to be able to take phone calls or talk on the radio.

“One of the things about dozers is having to anticipate the influence of your tracks going over clods and over a grade change, and it’s really more effective to be able to do that manually. On the average job we’ll fine grade with them and then we’ll set blue top hubs, mainly to let the client visually see that the grade is where it needs to be. Sometimes we’ll go back and clip it with a grader after we put out the blue tops.”

A civil engineer by training, Stanley agrees with Todd Moyer about control points. “Normally we like at least six control points. Sometimes we’ll send our regular survey crew out or layout crew to go with a total station and place additional control points if we have only two or three property corners that are available and/or if they’re unobstructed. A lot of times in our area, the property corner pin that we use for control is in hedgerows or at the edge of a tree line. That makes it difficult to get enough satellites. So a lot of times we’ll have to take a survey crew and actually place our control out in the open where we can get a good signal.

“We’ve also found established procedures to set up a permanent base on each job. We survey the location of the pole and the elevation of the unit it’s on, and all someone has to do is go out and place it on the pole, instead of setting up over a control point and trying to level up and plumb down.”

“You end up using it for more things than you thought originally—not just for grading but for checking things like manhole height. Instead of setting up the survey system, let’s say we want to know all the northing and easting of all the manholes on the job site in case they get covered up. The operator just goes to the vicinity, sets the blade, and writes it down.

“The way we do it is basically the excavator digs out everything, keeping close to grade, and then the dozer comes back and cleans it up. When you have hard material it vibrates the blade around, and it’s a lot easier and faster if the excavator just takes it down, say, a couple inches below where they’re supposed to go and just keeps hogging it out. Then whatever section you’ve got hogged out you just dump a couple of loads in and knock it off really quick with the dozer right to grade. Then you roll it and you’re good to go.

“This way one operator can use the excavator for taking stuff off and keeping track of his own grades, and the dozer can be over on the fill site or whatever, keeping track of his own grades and rolling. The nice thing about this is both machines are hooked up with the GPS and you don’t have to be line-of-site. You can have several machines hooked up to the same thing, running on the same unit, and have another guy digging footers by himself.”

“We usually have one of the motor graders with the GPS control on it on each job,” says Fors. “The dozer that’s equipped goes to the bigger job where we think it could come in most handily. It’s that much of a resource that they throw it on a lowboy behind a semi. At an airport job in Great Falls, for example, we actually shut down one portion of the job for about a week while we were waiting for the other motor grader to get there to get them going again.”

“Doing retail buildings is fast passed. We get them a pad and we might still be grading around the building when someone comes in and tears up the grades. Then we have to go back in and repair it so we can pave it. The problem is the metal decking will block the signal from the satellite and will also interfere with the radio signal. That’s when you need an operator who knows what he’s doing, who can determine the elevation based on the floor elevation and use conventional controls.

“Typically on a job we have the D8s out in front doing the rough grading. The D6s follow behind getting it to the plus or minus. Before we had a road grader set up with GPS, we were putting it dead on with the dozers. But now the dozers don’t have to spend as much time and the grader follows right in behind, polishing and putting the thing right on—and you don’t have any marks from the tracks. It leaves a picture-perfect job.

“I would like to get our mass excavators set up, ” Sippel adds, “but I’ve been debating about the efficiencies. What will probably happen is one day I’ll go out and see that we’ll have dozers tied up on a hillside or they’ll have undercut the slope, and I’ll get frustrated and call the dealer and tell him to give me another system.

“I never did a study to determine what the return was. But there’s no way we could have expanded the way we have using conventional stakeout.”

Journalist Penelope Grenoble O’Malley is a frequent contributor to environmental publications.

GEC - November/December 2006

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