Bridge inspections are a critical part of infrastructure maintenance. Regularly examining the condition of bridges allows engineers to identify damage and deterioration early so that repairs can be made before small issues turn into safety hazards. Traditionally, bridge inspections have been conducted manually by engineers performing hands-on assessments. This technology for bridge inspection is still developing but holds enormous potential.
This guide will explore everything you need to know about planning, conducting, and analyzing drone bridge inspections. So read on for more information.
Drone Bridge Inspection Equipment
A variety of drone models are well-suited for bridge inspection tasks. Small quadcopters and hexacopters specially designed for industrial use tend to work best. These agile drones can hover precisely and maneuver in tight spaces under bridges to meticulously scan all structural elements. Drones used for bridge inspection need advanced features like obstacle avoidance sensors, GPS stabilization, and redundancy features that allow them to continue flying safely if one motor fails. They also need to be able to carry specialized cameras and sensors to gather useful imagery and data. The most common payloads used for drone bridge inspections include:
● High-resolution visual cameras: Provide detailed photographs and videos of cracks, deterioration, and other flaws.
● Thermal imaging cameras: Help identify subsurface defects and water infiltration issues.
● LiDAR sensors: Use laser scanning to create detailed 3D maps of bridge surfaces.
The drone system also requires a rugged tablet or controller with software for real-time data transmission and storage. Additional accessories like landing pads, spare batteries, and cases help ensure successful on-site operations.
Preparing for a Drone Bridge Inspection
Thorough planning and preparation are crucial before deploying drones to inspect any bridge structure. The inspection team should acquire permits and authorization from state transportation departments and the FAA. Work areas must be properly surveyed and secured with signage and barriers. The bridge should be closely examined from the ground first to identify potential hazards or risks that could impact drone flight. It is also wise to scout potential launch and landing sites near the bridge that minimize flight distance. All drone equipment should be tested in advance to ensure it is in proper working order.
Conducting a Drone Bridge Inspection
Once planning is complete, trained pilots can launch drones to capture aerial imagery and data. Flights typically follow a systematic grid pattern, with the drone scanning the top and underside of the bridge deck as well as scaffolding, cables, trusses, and supports. Pilots must always maintain a visual line of sight with the drone and monitor battery levels, connection strength, and flight telemetry. The drone should be flown slowly at close range to record flaws as small as 1-2 mm while staying clear of any objects. If any issues arise during the drone bridge inspection, the drone should be immediately landed at its designated safe zone.
Data Analysis and Reporting
Once drone bridge inspection flights are complete, the real work begins. The imagery and sensor data must be downloaded, compiled, and analyzed using software tools. Photogrammetry algorithms stitch images into detailed 2D and 3D models that engineers can zoom in on and examine for signs of deterioration. Thermal data reveals temperature variations that indicate subsurface defects or water infiltration. LiDAR scans generate comprehensive digital surface maps with millimeter accuracy to measure cracks and wear precisely. All this vital data empowers inspectors to recommend maintenance priorities and structural integrity.
Training and Certification
It takes skilled, experienced teams to perform drone bridge inspections successfully. The FAA requires remote pilots managing bridge inspection flights to have a Part 107 commercial drone license. But hands-on training programs are also offered to provide pilots with specialized instruction optimized for navigating complex bridges.
Groups like the AASHTO Committee on Bridges and Structures are working to establish formal training standards and certifications specifically for drone bridge inspection operators. Nineteen state transportation departments have participated in the AASHTO UAS Bridge Inspection pilot project to evaluate certification criteria. As the use of drones for bridge inspection expands, formalized training and certifications will help ensure standardization. Regular continuing education and training will be important for certified drone pilots to stay updated with evolving technologies, regulations, techniques, and safety best practices. Qualified personnel are the foundation of effective drone bridge inspection programs.
Future of Drone Bridge Inspections
The future is bright for drone adoption in bridge inspections. As camera, sensor, and battery technologies continue improving, drones will be capable of even longer, more detailed inspections. Automated AI-assisted defect detection in imagery holds promise for easier analysis. Fully autonomous drones that can self-navigate complex bridges using pre-programmed routes may reduce the need for hands-on piloting. Integrating drones with other emerging technologies like rope-climbing robotics could enable new capabilities. Regulatory relaxations could also open the door for multi-drone fleets that accelerate inspections. While drones will only partially replace hands-on bridge assessments, their efficiencies ensure these technologies will dominate the inspection field moving forward. But proper training and responsible use will be critical as more transportation departments take to the sky for infrastructure surveys.
Conclusion
Regular bridge inspection and maintenance are essential to motorists' safety and the infrastructure's structural integrity. Incorporating drones into the inspection process improves this critical work with significant benefits - from reduced costs to enhanced data quality. Pilots need specialized skills to manage drones in confined bridge environments and properly translate aerial data into actionable insights.
But with the right personnel, planning, and preparation, drones are extremely powerful tools. While key challenges like weather, regulations, and data management exist, drone technology is primed to transform bridge inspection through greater accessibility, efficiency, and safety.
