Not long ago, the average construction worker might have seen drones as interesting gadgets, but not much else. Today, drones are serious business, and can give contractors a cutting-edge competitive advantage.
PCL’s drone pilots embrace technology to improve how the company builds for clients across every market it serves. Brad North, an integrated construction technology manager with PCL Saskatoon, is one example. He flies drones over project sites to conduct site inspections, and in 30 minutes, he’ll be able to complete what would have taken all day to do on foot.
In a site inspection, drones, otherwise known as unmanned aerial vehicles, help identify any potential obstacles on a job site, such as debris, materials or vehicles. “You have that immediate feedback loop of, ‘Here’s what we’re proposing, and here’s why it will or won’t work,’” North says.
North uses Site Scan software that automates the flight plan, so the drone flies within a certain grid pattern. In its brief flight, it snaps hundreds of photos. Soon, the drone will land within an inch of where it took off: Mission complete.
On a larger scale, however, PCL’s drone mission is just getting started.
Any company interested in drones must be deeply devoted to training, safety and innovation. The licensing requirements alone are rigorous: In Canada, to become commercial operators, aspiring pilots must pass written exams from Transport Canada or, in the United States, the Federal Aviation Administration. After taking a practical flight exam, like a driver’s test for drones, PCL’s aspiring drone pilots must take the company’s in-house competency test, which tests both their practical flight skills and their regulatory knowledge. It’s a lot of training, but the payoff is worth it.
For the construction industry, drones are primarily useful for photography. Aerial site photos and videos can help streamline inspections and site mapping, which helps construction companies identify problems on-site, track construction progress, assist with digital mapping and more. This can massively reduce costs for clients. On a recent SaskPower project in Regina, Saskatchewan, for example, drones helped PCL cut initial inspection costs by 80%.
Drones can take aerial 360-degree bird’s-eye-view photos from the exact same spot every day, so PCL superintendents can use them in their daily planning meetings. Drones capture information so software can create 3D models and scalable photos of the entire project site. These photos are then overlaid with the project drawings to make sure the project remains on track.
Even in the early days of its drone program, PCL used drones for services such as façade inspections, a practice unique among large contractors. (A drone can quickly fly up and down the side of a building and take hundreds of photos in minutes; imagine attempting that detailed of an inspection on foot.)
Mathew Hawkeye, a construction modeling specialist and drone pilot with PCL Winnipeg, adds that scanning a job site is much easier with drones than with traditional methods. “To properly capture a whole site with a traditional 3D laser scan might take me most of the day, because I have to set it up 20 or 30 times,” he says. “A drone scan would take maybe 15 or 20 minutes to get that data, and it would be accurate within a centimeter or two.
“Even for the project documentation alone, all the data deliverables we get are derived from photos, whether we’re looking for progress photos or a full-on scan,” he continues. “That can be anywhere from 200 to maybe 800 photos for a site. That’s a lot of information, and the tools we have make it easy to index and grab that information without sifting through the entire data set.”
As PCL’s drone program developed further, and as the technology and software became more advanced, PCL created new use cases. PCL began using drones for site surveys and even for estimating the quantities of materials on the job site, which is exponentially faster than traditional methods that use total stations. This is especially crucial on mass excavation projects, where estimating and monitoring earthwork quantities is vital for developing economical pricing and reducing costs and schedule risks during construction. Drone software can also create “point clouds,” a digital representation of millions, or even billions, of points plotted in 3D space.
PCL’s Orlando office has emerged as a leader in drone usage and has even completed drone flights for some of its local subcontractors. These practices distinguish PCL as a forward-thinking and innovative company, but they also help provide solutions for clients. Andre Tousignant, senior manager of integrated construction technology in Orlando, says it’s a service that can build local relationships. “Once we showed clients how we were generating models and actionable data — not just photos and videos — their jaws would hit the floor,” he says. “They’d say, ‘Wait, you’re doing that with a drone?’”
Larry Laxdal, integrated construction technology manager with PCL Regina, says that thanks to drones, “Project superintendents can have a map of their entire site updated every day with overlays of the project drawings that they can check to make sure everything’s on track. They can load in 3D design surfaces to check the earthworks on a regular basis and calculate how much more they have to excavate.” Once again, this is exponentially faster than using traditional means.
“On a daily basis, a site superintendent can have an overlay of the excavations that are required for site services, like sewage piping or water piping,” Laxdal continues. “There’s no way they could get that by just walking around. It’s the difference between being able to see immediately if there’s a problem versus having to go out there and survey everywhere, and then bring it back and check it in AutoCAD.”
PCL also uses drones for topographic mapping. For the Florence-Casa Grande Canal Reach 1 Project in Arizona, earthwork excavation and grading were required for the construction of a 3.5-mile stretch of concrete-lined canal. Earthwork activities were unit price bid items, so monthly topographic surveys were needed for accurate billings. More importantly, site grading within the canal prism was required to be within one-tenth of an inch of design finish grade for proper water flow.
PCL field engineers used drones to survey the progress on canal earthwork, and that data allowed PCL to create a large 3D model that it used to calculate cut-and-fill progress quantities. This also enhanced quality control in managing and monitoring finish grade activities, since PCL could ensure grading specifications were being met. The turnaround time was much shorter than it would have been with conventional surveying methods, and it also reduced rework and permitted timely adjustments.
There were other significant benefits to using drone mapping technology on the Florence-Casa Grande project. Safety was one: since employees didn’t have to be on the ground to perform conventional surveying, drones kept them away from moving equipment and other hazards on-site. Cost savings were another. Over the course of the project, the drone surveying system is estimated to have saved about $93,000.
Drones can also collect daily job site information and use the images to create combined “ortho-mosaics” — basically, high-resolution maps made from huge quantities of overlapped photos. These get pushed through AI engines that compare them against design documents, alerting the team of any differences. Processed overnight, the results go out to site superintendents the next morning.
Drones can even provide site thermographs — maps that depict variations in temperature — to determine which areas of a site are hotter or colder than others. This is especially valuable on solar projects, where drones can spot faulty panels or parts of the grid by differences in temperature. On a solar project with millions of panels, the cost difference compared to that of traditional inspections is almost impossible to quantify.
PCL continues to advance its drone program, further proving its commitment to innovation. As Laxdal says, “Our drone program is growing faster than ever. Every year there are massive leaps in the value that the hardware and software can deliver.” Drone technology is always improving, and the opportunities seem endless.
Maxime Beland, a project coordinator in Ottawa, has been flying drones for four years and is now using one extensively on Ādisōke, the new Ottawa Public Library and Library and Archives Canada Joint Facility. In Anishinābemowin Algonquin language, Ādisōke refers to the telling of stories. Every flight Beland takes around the construction site captures more pieces of the story for the project team and the client on the way to completing this important gathering place for sharing stories of past, present and future.
Looking to the future, Beland says changes in drone regulations are making it easier for people to start using them and the technology itself is moving toward even better precision.
“Right now, we're looking at centimeter precision, but some images are still blurry or there are inconsistencies,” he explains. “In the next few years, it’s going to be millimeter precision, and we’ll see that in the commercial drones we’ll be purchasing.”
PCL’s drone mission will never be truly complete — there will always be new ways to add value and new ways to be safer and more innovative. What matters is that whenever there’s an opportunity to add value for clients, PCL will be ready for takeoff.