Feature: Proving Groung
Professional Surveyor Magazine - December 2010
Automation advocates in Oregon display key grade-control concepts and demo equipment as they prepare the industry for standardized practices.
By Don Talend
Automated grade control has come a long way in terms of technological advancement in recent years. A critical element in the successful implementation of this type of automation as a standard practice is the human element, though. That’s why the Oregon Department of Transportation
’s (ODOT) geometronics unit recently conducted a “Design to Dozer” computer-controlled heavy equipment demonstration for about 250 ODOT personnel; contractors; officials for the city, county, and federal governments; surveyors; and consultants near Eugene, Oregon.
Several companies donated equipment, time, and expertise to the two-day event, including the PPI Group
, a construction and surveying technology provider with locations in Portland, Oregon, and Seattle; Topcon Positioning Systems
; SiTech NorCal
, a Hayward, California-based construction technology dealer; construction and engineering software provider Bentley Systems
; and local contractors K&E Excavating
, Pacific Excavation
, and Wildish Construction Co
A major catalyst for the event is a six-year ODOT automation plan launched in July 2009, intended to incorporate 3D designs into ODOT projects while ensuring data accuracy at each stage of the construction process, according to Ron Singh, PLS, ODOT’s chief of surveys and manager of geometronics, i.e., geomatics. “When considering engineering automation, I find it important to look way into the future to establish a long-term direction,” said Singh. “Trying to turn a large agency to a particular course is like trying to turn a big aircraft carrier around—it’s not going to happen quickly. One of the main reasons for this event was to get people to understand these things we’ve been talking about in a more real way. You can make presentations to people or write articles, but until they see the technology and touch it and actually work with it, they may not completely buy into it.”
Field Demos Reveal Reality
A highlight of the event was the field demonstrations. The attendees were divided into several groups to see demonstrations narrated by experts at six different stations. They witnessed the construction of the roadway subgrade and base rock using stakeless machine control systems such as Topcon Positioning Systems’ Z63 3D-MC2 GPS+ system, which was installed on a Caterpillar
140H motor grader operated by Pacific Excavation. At this station, Bill Painter, regional sales manager for Topcon, and Edwin “Shorty” Schuldt, machine control application specialist for the PPI Group, gave attendees an overview of how high-speed machine-control systems work and why contractors can significantly increase their productivity.
Machine-control systems are increasingly growing in modularity, he added. Painter pointed out that all major construction-machine manufacturers are equipping their machines with valves so that dealers such as the PPI Group can get a motor grader up and running with machine control in about six hours, compared with the day and a half it used to take.
At the next station, the PPI Group’s Ken Shersty gave an overview of a Topcon 3D-MC2 on a Wildish Construction Komatsu D65 dozer. The system uses:
- an MC-R3 Global Navigation Satellite System (GNSS) controller that works in conjunction with an MC2 sensor to replace a slope sensor,
- a four-color, touchscreen, Bluetooth-capable GX-60 control box, and
- a conventional GNSS antenna mounted on the dozer blade.
The MC2 sensor combines a gyro, compass, and inertial sensor to measure the X, Y, and Z position as well as the roll, pitch, yaw, and acceleration of the dozer. The technology gives the system the capability to provide blade position readings up to 100 times per second—or roughly five times as many as conventional GNSS.
Shersty pointed out the fact that the operator and grade checker verified the dozer’s position using control points and were off and running without the need for stakes. He asked the audience how much they thought it cost to get a stake in the ground, surmising that $50 sounded about right. On a road stretching less than half a mile like the one on the site, Shersty estimated that about 400 to 500 stakes would be needed under conventional grading practices. The cost savings that machine control would generate in such a scenario is $20,000–$25,000, Shersty noted.
A little down the way, K&E Excavating discussed its construction of a bioswale using a Caterpillar 300 excavator equipped with a grade-control system provided by SiTech NorCal. Another station, dubbed “the Technology Site,” featured a Komatsu
220 excavator equipped with a Topcon X63 grade-control system and, mounted on a passenger car, Topcon’s new IP-S2, which combines GNSS, an IMU for tracking vehicle attitude (pose), and external wheel encoders that capture odometry data from the vehicle, 360-degree digital imaging, and laser scanners. The IP-S2 can be used to capture position coordinates, lidar data, and video footage that transportation officials can use to monitor comprehensive roadway assets and structural features for maintenance purposes.
Brad Carlsen, president and general manager of Pacific Excavating in Eugene, has used machine control since early last decade and GNSS machine control since 2006. Carlsen counts productivity, cost savings, and safety as the main benefits of machine control. “I think Ron [Singh] has got local people listening now and this event makes it real,” he said. “When you can see a stakeless road being built with machine control—that, to me, speaks volumes.”
He added that surveyors in his market are realizing that machine control is here to stay. “They’re embracing it from the standpoint of working with us on the electronic models,” Carlsen said. “They’re also understanding that surveying still needs to happen on a project and they’re working in parallel with us—in a different role, perhaps, but they’re still providing surveying services for the project overall.”
Presentations Stress Uniformity
The presentations covered automated grade control in considerable breadth, with an emphasis on its usefulness throughout the construction process and ensuring data accuracy among project team members. Here are some highlights:
Singh opened the event by advocating the widespread use of automated grade control—which he described as a disruptive technology, one that forces the industry to change its processes. To date, he said, ODOT has traditionally used a “reactive, project-centric” approach to managing its engineering data. In this paradigm, all survey and design data are created for a specific project but not used beyond construction. As-built construction plans are developed when a project is completed, and the site is re-surveyed when a change is required at a later date.
Singh argued that care must be taken to ensure accuracy while automated grade control systems are in use. In his experience, he said, when things go wrong with automated grade control, the design (i.e., formatting problems) usually is the cause. Also, the use of automated grade control systems is affecting many different professionals on a project. Engineers will begin to provide coordinate-correct 3D designs based on buildable files, not just designs from which bids are developed.
Surveyors will always have a key role but will be responsible for providing control points and managing data, says Singh. Inspectors will need to get used to working with positioning data, but will get less support from surveyors than in the past, and increasingly they will need specialized positioning-oriented tools to do their jobs.
3D design for machine-control grading
Tom Metcalf, PE, lead engineer on the nearby I-5 Williamette Bridge project for OBEC Consulting Engineers of Eugene, presented “3D Design for Machine Control Grading.” The project involved 2,500 feet of roadway work, twin 1,900-foot bridges, and 2,300 feet of roadway and ramp reconstruction. On one side, the I-5 roadway actually had to be raised several feet, and staging posed challenges. Metcalf noted that the grading contractor, K&E Excavating, asked to use machine control on the alternative delivery project to keep material quantities accurate and to reduce costs.
So OBEC used InRoads XM software to generate digital terrain models (DTMs) for K&E’s machine-control systems. This was a case of adhering to a new industry standard of accuracy needed for automated grade control that entails more design time in order to reduce field modifications, in contrast to the old industry standard of “close enough modeling” with allowances for field personnel to fill design gaps in the field, according to Metcalf. Structures requiring finer detail or incorporation into designs include guardrail benches, side slope transitions, structure section transitions, and drainage features.
Metcalf argued that more detailed designs force roadway designers to work more closely with structural designers. Even though experienced field personnel are needed to “fill gaps” in designs, and change orders might be needed to fill the gaps, the upside of machine control is less expensive projects and more work for contractors who are proficient at using it, he added. “One thing you’ll hear a contractor say when you’re working with them on a day-to-day basis is that design dollars are always way cheaper than construction dollars,” said Metcalf. “You’re way better off expending the extra money and time designing the project to a much tighter level than you are fixing things out in the field.”
Incorporating the Takeaways
Singh was optimistic that the event convinced many attendees of the benefits of automated grade-control technologies and moved them closer to making them an integral part of their day-to-day operations. The key factor in meeting the goals of ODOT’s draft automation plan will be a commitment of resources to initiatives, he argued. “In the day-to-day grind of getting projects out, managers aren’t that eager to devote time and resources to develop something for the future,” Singh said. “We [ODOT] cannot get this done with people who already have a full-time job and whose day is already fully accounted for—we have to devote additional or new resources to it. If I can change one person’s mind as a result of this event, I will have made progress. There are a lot of people here who I know from the past were very skeptical about this but who now are leaving with a slightly different mindset.”
Carlsen welcomed implementation of the automation plan. “I think that when it comes fully to fruition, it’s going to help in a lot of ways,” he said. “First of all, from an estimating standpoint, we’ll have electronic data to bid off of; we won’t have to recreate it off of the paper drawing. We’re hoping that we’ll get to the point where the electronic design can be transitioned fairly seamlessly to what we need, which is 3D models that plug into our Topcon machine control and our GPS ground control without having to go through several steps that we have to go through now to get it there.
“I think that’s why what Ron at ODOT is doing now is really a good thing because it’s setting the groundwork for that to happen—it’ll make it more seamless from design through the build process for everybody. It seems like the barriers now are getting the accuracy of the files coming out of design to the level of tolerance that we need on machine control. The design people just need to make the data a little more accurate with regard to tolerances. This will have been a successful event if the owner agencies and the contractors see that, if we get this to a seamless process, [automated grade control] is of benefit to their projects.”
*Event Materials Available Online
: Design to Dozer
presentations and a draft of the ODOT six-year plan.
Don Talend of Write Results Inc., West Dundee, Ill., is a print and e-content developer specializing in covering technology and innovation.
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