What would happen if we had an aerial view of our job sites?
That was the question that Bill Bennington and André Tousignant, as part of the virtual design team at PCL Construction in Orlando, starting asking themselves years ago. While they had experience using advanced reality capture technologies in the field, for a long time the PCL Construction team couldn’t justify using drones in construction: they were expensive, and time-consuming to set up, pilot, and process the data. Even if they got over those hurdles, stringent regulations made it difficult to be legally allowed to fly in the first place.
However, the technology continued to improve, and in August 2016 the FAA Part 107 regulation came into effect, dramatically lowering the legal barriers to entry for commercial drone pilots. Bill and André finally saw an opportunity to finally bring drones on-site, and they started exploring how drones might drive value on a few key projects.
Their first step? Finding and evaluating different solutions, and determining which one was the best fit.
Which Drone Solution?
To get started, Bill, André, and their VDC team developed 5 core qualification criteria to find the right solution for their needs:
1. Data, Not Video
Initially, PCL thought that a top use case for drones was making videos for marketing purposes. It soon became clear, however, that they could easily do this with low-cost, consumer-grade drones, or by working with a local service provider. The bigger opportunity for the team was to use drones to collect aerial data for measurement and analysis. This called for more advanced hardware and software, so they focused their evaluation on commercial drone solutions with more capabilities.
2. Data Quality (Absolute and Relative Accuracy)
Once they decided to collect data, not just imagery, accuracy became the next big factor. Like many other contractors interested in using drones, PCL Construction had two kinds of concerns regarding accuracy:
Absolute accuracy: If I’m using data from the drone to overlay with plans, will everything line up? How do I know when something appears out of place if it’s due to a georeferencing error, not an actual construction issue?
Relative accuracy: If I’m using data from the drone to perform measurements such as stockpile volume measurements; will I get accurate numbers compared to traditional measurements?
Bill and André decided they needed absolute accuracy to the tenth of a foot, and relative accuracy greater than 99 percent compared with traditional measurements. When necessary, they planned to use ground control points to georeference their aerial data, helping further improve accuracy.
3. Image Quality
Since drone photos would initially replace the monthly photographs taken by a manned helicopter, PCL Construction needed to ensure that drone image quality would be just as high, if not higher. Ultimately, they decided to compare a high-resolution oblique (side angle) photo from a manned aircraft with a high-resolution orthomosaic image from a drone, comprised of a series of nadir (straight down) photos. They evaluated orthomosaics from different drone solutions with three main criteria: resolution (ground sampling distance), sensor size of the camera, and image lens distortion.
4. Interoperability & Workflow
While evaluating options, Bill & André made sure to take note of the file types that different drone solutions could export. PCL relies heavily on Autodesk products including AutoCAD, Civil 3D, and ReMake, so it was vital that drone solutions worked seamlessly with their existing tools and workflows. Scalability was important too, given their goal to have drones on every job site within the organization.
5. Customer Support
At this point, PCL Construction had not yet used commercial drones on-site. This made it critical to receive excellent onboarding and ongoing customer support, in order to quickly get up to speed with the product and quickly resolve issues. Any solutions without warranties were also a no-go: replacement units had to be readily available if they ever had any issues with hardware on-site.
Bill, André, and their team ultimately decided to go with 3DR Site Scan as their drone solution. After a rigorous selection process, they found that Site Scan best met their criteria: it provided actionable data, high quality imagery, seamless workflow integrations with Autodesk, and excellent onboarding and customer support.
“What it came down to, for us, was the simplified workflow, the support we received from 3DR, and the scalability of the product. We also liked using both 3DR hardware and software, along with the integration that 3DR has with Autodesk in cloud processing.” — Bill Bennington, PCL
Getting to work
After deciding to go with Site Scan and start to integrate drones into their projects, Bill and André then started to identify people within their team to become certified FAA Part 107 pilots. There was no shortage of interest, and field engineers like Alyssa Odom — who we profiled here — studied with the Part 107 resources and passed the certification test. In no time, a number of PCL field engineers earned their Part 107 certification and were taking off with drones on various projects. Here are a couple examples:
Case Study 1: Crystal Lagoon
PCL Construction also used drones on their Crystal Lagoon project, which we went into detail on in a customer story, to make their QA/QC process more focused and efficient and provide more detailed progress updates to their client. This helped save significant surveying time on-site, cutting down the process from 1 week to just 1.5 days.
Case Study 2: UCF
Just one week after getting their drone, Bill and André brought Site Scan to a project for the University of Central Florida (UCF). They flew the site in under 12 minutes, and in a day they were able to process the aerial data into a point cloud of existing conditions and site lines. Ultimately, this helped them do a cut and fill analysis of a large stockpile far faster than their traditional workflows.
Next step: Scaling drone workflows
After successfully choosing a drone solution and proving the value of using drones on-site, PCL is now focused on getting drones on more projects and scaling the workflow across the organization. They’re planning to do this in three steps: first, establish a clear workflow within VDC teams for how aerial data will be processed and used. Next, they plan to ensure that field engineers and superintendents across the company to obtain Part 107 certification and be able to fly drones on site. Once they are able to define their workflows both in the field and the office, PCL will be able to scale their drone operations across the company.
While aerial data and cutting-edge technology are nothing new to a company like PCL, the steps needed to utilize drones as a tool in construction required research, education, and clear decision criteria. The key to the success of PCL’s drone program has been a commitment to a streamlined workflow that was scalable across multiple jobsites. As Bill said, “If you can demonstrate how you can improve an existing process with the use of a better, more efficient tool, every project will want one.”