It’s tough to find a construction job that doesn’t rely on surveying. From initial planning to final As-Built verification, surveying plays a crucial role, often in multiple phases, of virtually every project.
While there have been significant advances to surveying throughout the years, terrestrial methods, commonly used on most jobsites, still come with challenges.
As one of the nation’s top builders, Mortenson Construction is no stranger to these challenges. A time-consuming process, density of data, and timing in availability of that data rank high among concerns. Known for using leading-edge technology, Mortenson is looking to improve on the survey process.
In March 2016, during the initial phase of a major renewable energy project, the company seized the opportunity to test UAS (Unmanned Aerial System) technology.
SEEKING A BETTER WAY
Unmanned aerial systems have been around for years but the popularity of drone use on jobsites has grown dramatically in recent years. From bridge inspection to agricultural scouting to disaster response, curious and innovative professionals, across numerous industries, are discovering the practical business benefits of drones.
Taylor Cupp, assoc. AIA, LEEP AP BD+C, is one of these people. As project solutions technologist for Mortenson, Cupp is involved in several types of projects and, throughout the years, has always looked for ways to be more efficient and effective on the jobsite.
In March 2016, Mortenson began a project with a longtime solar client. Mortenson would be involved in the complete scope of the project, starting with a site prep phase that called for moving of 750,000 cubic yards of earth, all the way through to final solar panel installation across the farm’s 350 acres.
Because of the large amount of earthmoving involved in the site prep phase, the density of survey data, delivery timeframe, and data collection time were all concerns.
Another challenge posed to the team: existing vegetation and other site characteristics would limit on-foot and vehicular access to certain areas for staking, further compromising the data accuracy of the overall site.
DIVING INTO DRONES
A few years back, a friend of Cupp’s purchased a drone for recreational use.
“One day he was showing me all the ‘cool’ things the drone could do and I remember thinking about all the possibilities I could see it having on the jobsite,” Cupp recalls.
Fast-forward to the 2016 solar project, and this was a chance to put that hunch to the test on the site prep survey work.
Mortenson already had a longtime relationship with RDO Equipment Co., a local dealer of John Deere and Vermeer construction equipment. Cupp knew there was a division of the company, RDO Integrated Controls, offering drones and expertise in UAS technology. So he reached out to general manager, Adam Gilbertson.
RDO Integrated Controls is an authorized dealer of senseFly and its eBee drone. Gilbertson was excited for the opportunity to show Mortenson the value of the eBee, saying, “We were confident it would deliver on the data accuracy and timeliness factors that were important to the team.”
Gilbertson and three of his colleagues joined Mortenson on the project site to begin the experiment.
Featured Image: RDO Integrated Controls is an authorized dealer of senseFly and its eBee drone.
Above: The eBee flew the site five times, with each flight lasting 36 minutes. In total, it generated approximately 2 billion data points at a density of 2 centimeters per pixel.
PUT TO THE TEST
Mortenson relied on machine-controlled site grading for a quality check. Initial survey work was done to establish control. Then, it was time for the eBee to take flight.
The eBee flew the site five times, with each flight lasting 36 minutes. In total, it generated approximately 2 billion data points at a density of 2 centimeters per pixel. According to Cupp, this was an “astronomically” denser amount of data compared to the terrestrial method, which pulled data points at only every 10 to 15 feet.
Aerial imagery was gathered and processed with photogrammetry technology to generate topographical data of finish grade and rough grade of the site. Thanks to the quick turnaround of the eBee, Mortenson was able to collect and analyze the data that same day.
WITH FLYING COLORS
In comparison to the terrestrial survey method, the eBee showed topo density improvement of 300 times, an 84 percent topo accuracy improvement, and a 40-hour time savings.
While Cupp says these metrics were crucial in proving the value UAS technology brings to the jobsite, the real value came from something immeasurable.
“Where we saw the major value of UAS was in the real-time assessment and availability of data,” he says. The technology feasibly allows information to be captured throughout the life of the project. The constant flow of information enables more informed decision-making and adjustments by the team. It also allows consistent and frequent progress tracking.
As for how it integrated into the jobsite, Cupp was pleased by how easy it was to operate the eBee, saying, “It’s almost too easy to fly!” Generating useful outputs that can cut down on lagging indicators was almost immediate.
He further pointed out that he’s very optimistic about the FAA’s new Part 107 rules for commercial drones making the use much more obtainable for companies looking to leverage the potential of drones on construction sites.
The eBee also proved to be unobtrusive, according to Nick Gubelli, civil superintendent for Mortenson, who comments, “Had I not known that someone was flying the jobsite, the shape of the UAV and the lack of any sound emission would have led me to believe there was only a bird soaring above the site.”
Sera Maloney, Mortenson’s director of integrated construction, spoke to the eBee’s safety, saying, “In the event any contact had been inadvertently made, the design of the UAV [being mostly Styrofoam] puts the risk of injury to our team and equipment to almost zero.”
THE FUTURE OF UAS
While Mortenson isn’t flying drones on every project site, there is a lot of focus and excitement around emerging technologies that capitalize on these new forms of output. Mortenson is currently researching new forms of computer vision and machine learning to make the most out of UAV data and better track productivity, progress, and quality.
“Drones fit perfectly into feeding data into evolving forms of ‘big data’ uses,” Cupp says.
While there’s certainly a place for the eBee on future Mortenson projects, one has to wonder if drones in general are on the path to becoming less of a luxury and more of a standard tool in every company’s toolbox. If you ask Cupp, Gilbertson or any of their colleagues, the answer is a resounding, “Absolutely.” ■
About the Author: Lindsay Paulson is public relations specialist for RDO Integrated Controls (www.rdoic.com) and RDO Equipment Co. (www.rdoequipment.com). Contact her at . For more information about Mortenson Company, visit www.mortenson.com.
Modern Contractor Solutions – August 2016
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