Construction industry professionals have long envisioned technological disruption to address common challenges of time and cost overruns to construction productivity and material wastage. Gone are the days when each task at these expansive project sites was to be carried out manually, as the use of technology innovations like robots, machine control, telematics, and unmanned air vehicles (UAVs)/ drones have taken over, ensuring maximum efficiency while reducing material wastage. Additionally, the rising complexities at the project sites justifies the use of drones, which are usually preferred for tasks that are either dangerous, dull, or dirty.
How do drones in construction work?
Drones/UAV provide construction stakeholders with expansive, accurate, and precise spatial data. The data obtained through a drone can be analysed with an engineering software and furthermore, can be overlaid on construction drawings. The data captured via each flight is processed through a photogrammetry software which is then used to create digital elevation models (DEMs), orthophotos, and 3D point clouds. A variety of secondary data products such as shapefiles, contour lines, and raster products are created when imported into a geographic information system (GIS). Furthermore, the overlaying of spatial data on CAD/construction drawings allows professionals to compare ‘as designed” to “as built”, thus enabling the identification of spatial mistakes well before they are executed on site.
Drones in Construction: The Past and the Future
Before the advent of aerial drones, the traditional method to get the site data was carried out on-foot or via manned aerial vehicles. Using drones, the construction professionals have leveraged the opportunity to get up-to-date images as often as they like in real-time. Drones in construction allow contractors a chance to monitor any issue, track progress and develop better plans on-site by providing an unrivalled view of a site at a fraction of the cost. This has largely been related to various aspects of a construction project from deploying labour, material wastage, site inspection, and an overall return on investment (RoI).
For instance, Norway has earned the title of having the best and safest road network in the continent since 2015-2017, which is being overseen by the Norwegian Public Roads Administration. The agency is targeting a zero-fatality goal by 2024, while using drones for surveying, to which the agency has reported cost savings by use of VTOL drones. Also, the field time savings were reported to be cut down to an hour from 5days.
In the current Covid-19 scenario, there has been a sudden surge in demand for remote site monitoring. Construction professionals all over the world are gradually up taking the adoption of drones/UAVs in various construction phases due to a gamut of operational and monetary benefits. Drone deployment has largely been witnessed in projects carried out by some of the international companies such as Vinci Construction, Kier, and Balfour Betty. Felsburg Holt & Ullevig, another engineering/architectural company is using drones for surveying the right-of-way project in Colorado. Using a fixed-wing drone system for an extended flight time, a highly precise topographic base map along with orthorectified imagery is generated. This in turn, results in considerable time and cost savings, giving a superior visual output/deliverable.
Drones in Transport: Benefits and Challenges
Benefits: From preconstruction (for placing accurate bids) to operations & maintenance (survey) phase, drones have proven to be of use during each lifecycle of a transport construction project. There is a seamless integration and collaboration of resources and stakeholders, with data being shared in real-time. A complete rendering of a jobsite helps in evaluating the flaws and loopholes well in advance. This in turn, ensures better project management approach with reduced project timelines, accurate site inventories, improved communications, and improved safety.
The benefits pertaining to adopting drones at site are numerous and their impact is listed below:
- Enabling better construction site monitoring
- Calculating stockpile volume and material types for inventory
- Document registry: Search tag and find equipment on site
- Calculating length, width and elevation for roads and structures
- Annotating images and maps for easier communication
- Calculating overburden to plan for an efficient removal
Globally, it is acclaimed by industry experts that drones will be considered as a standard technology tool kit in upcoming construction projects. Drones with ground control points (GCP) and thermal sensors are expected to gain wider acceptance due to an array of benefits to the construction productivity and predictive analysis of future events. Machine learning and AI advancements will make it easier to gather data and accelerate the process from capture to insight. Moving forward, there is nothing but upside for thermal data captured by drones.
Challenges: Regulatory hurdle appears to be the biggest growth barrier for wider drone adoption. In the United States, the Federal Aviation Administration (FAA) mandates drone fliers to get a certificate of registration before flying any unmanned air vehicle (UAV) on a construction site. The failing of the mandate will lead to a fine ranging from US$ 27,500 to US$ 250,000 including imprisonment.
Also, the price of a drone plays a crucial aspect in the selection of drone, which again varies basis the final scope and deliverable requirement (accuracy, resolution, flying time, swath, file type, etc.). A small sized drone kit with a mounted camera of 20 megapixel can be available for US$ 2,500 and can go up to US$ 15,000 for an industrial-type drone. A much higher variant ranges in between US$ 75,000 to US$ 100,000 for a drone mounted with LiDAR sensors. Thus, it becomes vital for any project owner to buy a drone based on the project requirements which can be a fixed wing, multi-rotor, single rotor helicopter, or a fixed wing hybrid VTOL.
Drone Deployment: Trends
Recent developments in airborne laser scanning (ALS) or airborne LiDAR category has enabled 3D area-wide data acquisition of topography, vegetation, buildings, bathymetry, and infrastructure. One of the innovations in drones for construction is miniaturization of LiDAR on drones, leading to a centimetre level 3D point clouds of ultra-high resolution. The industry is moving towards an amalgamation of active and passive sensors for airborne mapping such that, all airborne sensors feature laser scanners, CIR, RGB or sometimes multispectral cameras which helps in dense image mapping (DIM). The construction sector is using these sensors for an accurate and early detection of errors.
The upcoming trends driving the commercialization of drones in construction industry is largely carried by the AI-software powered drone. The inclusion of AI ensures the stacking of unstructured aerial data captured via drones to actionable and structured data, which given an end inference to an upcoming hazard or error. The amalgamation of cutting edge technologies (like AI, AR/VR, sensors) helps the drone industry in producing a quantum leap in the data useable by the industry, thus, reducing on the cost and increasing safety while maximizing performance.