Technology's Impact Anything but Median for Albany-area Contractor

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For decades, a section of the New York State Thruway between Exits 23 and 24 has been a major headache for Albany area commuters. Drivers seeking access to downtown or the I-87 Northway are in unanimous agreement that this nearly seven-mile section of the Thruway is badly in need of an upgrade. In one of the largest single projects undertaken by the New York State Thruway Authority, Rifenburg Construction was selected to help ease those travel pains. The $99.9 million reconstruction effort began in 2011 and included replacement of the asphalt surface with concrete, the addition of a full lane of traffic in both the northbound and southbound directions, and the installation of a seven-foot-tall concrete barrier wall between the two.

That project--and scores of others-- are kept on track through Rifenburg's use of GNSS-based equipment including dozers, motor graders and pavers equipped with Topcon's 3D-MC2 and Millimeter GPSTM machine control systems. In fact, the company's commitment to the technology is so strong, they like to say they don't simply use GPS, they run on it.

Setting the Wall
Based in Troy, N.Y., Rifenburg Construction has a rich history that spans 56 years. In that time, the company has seen tremendous change, none perhaps more impactful than its migration over to GNSS and machine control. A longtime proponent of the benefits GPS can bring to the jobsite, that willingness to embrace the technology really came to light on the recent Thruway project, according to project surveyor Mike Momrow.

"Because of its proximity to downtown and the Northway, this section of the Thruway was prone to serious backups during the morning and afternoon rush hours, so plans have been in the works for some time to make changes," he said. "The original design on the job had a large number of discrepancies, but once we got those issues resolved, we were off and running."

A centerpiece of the project--both figuratively and literally--the median wall that runs the length of the project was one of the more challenging aspects of the project. Momrow said Rifenburg's expertise with GNSS (in this case Millimeter GPS) made all the difference in efficiency during that facet of the project.

"This is a segmented concrete barrier, so the base upon which each section rests had to be extremely accurate-- grades to within a quarter inch--for the segments to sit right. We used a John Deere 650D running Topcon's Millimeter GPS and, running off a surface model I built for the project, graded the area underneath the barrier. We had PZL-1 lasers positioned 600 feet apart and were able to easily get the accuracy we needed. We would grade it, lay down a course of crusher run, ride a roller over it, then place a skim coat of stone dust that could be hand-raked before placement of a wall segment. It was a great process all the way through."

Time Well-Spent
The degree to which GPS helped Rifenburg on the Thruway project is magnified when alternative methods are considered (Momrow says the job was essentially done without the use of survey stakes). Had it been done conventionally, the pace would have been greatly impacted and the additional costs would have been considerable.

"Had we used stakes and stringlines, it would have been a whole different job," he said. For one thing, I would have needed to be out here all day, every day, for the entire summer of that wall work. That alone saved 2,000 man hours of survey time. In addition, to help place that barrier, we set up a Topcon GR-3 rover with a millimeter head and had a poly line that the foreman--using an FC-250 data collector--followed. In that manner, he could set every piece on grade without the need for a level, keeping those tight accuracies up but doing so quicker and much more efficiently."

He says that Rifenburg's embrace of GPS technology is long-lived and has changed the company's survey-related staffing. "I've been here a long time and Rifenburg had no GPS when I first started," he said. "Back then we had three survey crews, with each crew consisting of two or three men. Now the entire survey function is headed up by me and my counterpart, Brian McGrath. So the impact, just in repositioning people within the organization, has been impressive."

Management Buy-In
One scenario that often comes into play for contractors like Rifenburg who rely so heavily on GPS is the need to convince project inspectors of the validity and reliability of the technology. On the Thruway job, said Momrow, nothing could have been further from the truth.

"The inspection team for this job was so in tune with what we were doing that they actually had us supply them with three Topcon GR-3 rovers for their dedicated use. I would load all the info into each unit for them and they would go out and capture every single element we completed. They also took topo shots and used that to generate 3-D models for pay requisitions. Before a pay req, the inspector would send me all of his info detailing what he used to generate that number--quantities, surfaces and so on--and ask if I agreed with it. It was certainly different from what we're used to, but really a welcome change."

Momrow said that, for record drawings, the Thruway inspection staff developed detailed subgrade models shot every ten feet. Their use of the GR-3s was written into Rifenburg's initial contract, again, a departure from the norm.

"They actually wanted two mapping units and two GR-3s, just to verify what station they were at," he said. "We talked them into getting three GR-3s and one mapping unit and I think they'd agree it was good move. Their use of the technology quickly evolved into them using it pretty much as a surveyor would. Within two months of getting the units, they were asking questions about how to use it even further. As a result, for much of the project, not only did I have the foreman out there making sure everything was right, I had three Thruway inspectors doing it as well. So, on any given day there were six rovers at work onsite. That kind of redundancy can catch errors before they can cost money."

Fast and Accurate
Not far from the Thruway job, in East Greenbush, Rifenburg was also wrapping up work on a fast-track job to install a much-needed roundabout. According to Momrow, the increasing number of such quick projects makes the use of GPS almost imperative.

"The timeline on this job--called the Route 4 and Mannix Road Bypass--was 40 days from start to finish. It is a roundabout at a very dangerous intersection that never had a traffic signal. Many of the road projects we are seeing these days are compressed to avoid inconveniencing the traveling public. So the pressure is on to get it done and get it done right. We have the technology to make that happen."

He said McGrath built the 3-D model for the site and, like the Thruway job, they used machine control to complete it virtually without stakes.

"I'm not going to say that this couldn't have been done conventionally," he said, "but on an aggressive job like this we would have to basically dedicate a surveyor to it for at least half the length of the project. Instead, we had a good grade foreman onsite who did his own grades; the surveyor only came in and laid out the curb at the end. Out of the project's 40 days, instead of a minimum of 20 days of surveying, we had a guy out there for about seven. We cut our survey time by more than two-thirds; that's direct bottom line savings."

Mature But Growing
Though they are one of the biggest proponents of GPS (32 systems alone-- and counting), Rifenburg is still finding ways to further maximize efficiency. Momrow is convinced that if equipment is managed properly and used creatively, survey dependence can be reduced by as much as 90%.

"For a lot of our work, we now have to provide final topo maps," he said. "So our foreman simply hits `enter' on the data collector and he can topo the entire job. I can take those northings and eastings elevations and develop my as-builts. What that means for us is that I don't have to go back and spend days at a time trying to catch up with what my crew did. So the deliverable at the end of the project is so much better. That's what's gotten us to the point we are at today and that's what will continue to take us forward."

Larry Trojak is a communications writer for his own firm, Trojak Communications, in the town of Ham Lake, Minnesota. He is a frequent contributor to construction and survey magazines.

A 1.868Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE

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