Drones are unmanned flying vehicles, which typically are remotely operated. By attaching sensors to a drone, it can be used for mapping terrains, making virtual models of built structures, inspecting maintenance needs, or monitoring the progress of a construction project.
Within the construction sector, drones are typically used for
- mapping a terrain to plan the need for moving soil before initiating construction
- scanning a built structure to model it in 3D/BIM before a construction project
- inspecting the maintenance need of hard-to-access structures such as bridges, wind mills or roofs.
- monitoring the progress of a construction project e.g. through weekly surveys estimating stockpile volumes
- surveying the construction site, e.g. to detect safety issues
Today, most drones used in construction are controlled remotely by a drone pilot standing on the ground, and according to current regulations in many European countries, drones need to be within the eye-sight of a human controller. In other cases, the drones are automated to fly according to a pre-defined flight plan. Depending on the task, different sensors, such as cameras, thermal cameras and LiDAR, are attached to the drone. Furthermore, ground control points whose GPS position is known can be used to geotag the scanning and ensure accuracy.
To supplement drone data, small autonomous or semi-autonomous rovers can be used e.g. for inspecting buildings and other narrow passages from the inside.
Benefits and challenges
- Cheap and easy way to scan an area (compared to e.g. airplanes and humans)
- Accurate calculations of area, volume, and distance.
- Improving safety, as humans are removed from dangerous tasks.
- The ability to incorporate maps, photos and 3D models into existing construction workflows
- Legislation limits the use of drones for commercial purposes. A drone license is necessary.
- Good weather conditions (e.g. clouds and wind) necessary.
Application examples
The engineering consultancy NIRAS has applied drones to do reality modelling of a bridge in Copenhagen. Combining laser point clouds, a large number of photos and geo-tagged ground control points, NIRAS made a photorealistic representation of the bridge. The resulting 3D reality model was used as a frame of reference for discussions between the parties involved in the construction project (www.niras.dk).
In Finland, the general contractor Lehto Group uses drones to do weekly scans of their construction sites. Laser point clouds and hundreds of photos from the drones are combined in Pix4D software. Construction stakeholders can monitor the progress on site by comparing the as-designed models to the as-built models (www.pix4d.com).
Development stage
Drones are already being deployed by many construction companies, and the adoption is growing heavily.
Construction impact
Drones affect all phases of a construction project. In the design phase, drones are used to map the current state. In the construction phase, drones may be used to monitoring progress and survey site conditions. In the use phase, drones can be used to detect maintenance needs e.g. by using thermal images to detect cold and heat spots.
Read more
www.geospatialworld.net
blog.dronedeploy.com
constructionreviewonline.com
www.ainonline.com