Implementing drone-based bridge inspections is economical, time-saving and convenient for the U.S. Department of Transportation and the public. The design service life of a bridge is usually between 50 and 100 years, but structural defects and aging of facilities can reduce the service life by almost 70%. Therefore, regular inspection and maintenance of bridge buildings are necessary, and drone inspections are alleviating such costly and dangerous inspection problems.
The current situation of American bridges
- According to statistics from the Federal Highway Administration, 42,951 of the 620,588 bridges in the country, nearly 7%, were considered structurally deficient last year.
- In 2022, half of the 20 most frequently traveled bridges in the United States were classified as structurally deficient and were at least 60 years old.
- In 2021, the U.S. Department of Transportation estimated that the total cost of repairing or replacing these structurally deficient bridges was more than $54 billion.
- Take New Jersey, for example, there are more than 6,000 bridges in the area, and more than 7.8% of the bridges are structurally deficient.
Therefore, bridge inspection and bridge maintenance have become one of the important tasks of the U.S. Department of Transportation year after year, and the cost is high. The total cost of repairing or replacing these structural defective bridges is more than $54 billion.
It can be said that we are looking for a new bridge inspection solution that improves efficiency and saves costs! Can drones help bridge inspection?
Traditional bridge inspection
Traditional bridge inspection relies mainly on visual inspection. This may take several hours or even days. Participants include engineers, bucket trucks and operators, and climbers with ropes. If it is necessary to close part of the lane on the bridge, traffic control personnel and police are also required to be present.
During the inspection, the inspector will evaluate the overall condition of the bridge and determine where more detailed inspections are needed. This includes aging, corrosion, material fatigue, extreme environmental loads and accidental impact damage of the bridge structure, cracking of the bridge deck, delamination, section loss, foundation settlement and many other inspection items, and the results of visual inspections often rely on the experience of the inspector.
Will drones improve these situations when used for bridge inspection? Let's continue!
How Drones are Used for Bridge Inspection?
Drones are valuable for bridge inspections because of their maneuverability, autonomous obstacle avoidance, visible light/thermal imaging camera sensors, and real-time transmission systems.
Camera drones can visually inspect bridge structures faster and safer. Remotely controlled drones can easily reach areas of the bridge that are difficult to reach manually using bucket trucks or rope climbers, capturing high-resolution RGB images/thermal images for evaluating structural defects.
Cutting-edge drones provide real-time 1080p resolution video, which can be broadcast live or transmitted to third-party devices so that more decision makers can watch and analyze it for better decision making.
Why do we need drones to inspect bridges?
Drone programs are becoming more and more effective in inspecting bridges, which are efficient, safe, and economical. With the advantages of drones in bridge inspections, inspectors and transportation bureaus can accurately decide whether to maintain, repair, or replace aging bridges. After bridge repairs begin, drones can also be used to track progress, provide continuous updates, and perform before-and-after comparisons.
Improve safety
Traditional bridge inspection methods usually require workers to climb bridge structures or use aerial tools such as hanging baskets, which poses a greater safety risk. Drones can inspect without touching the bridge, reducing the risk of worker injury.
Save time and cost
Drones can quickly cover large inspection areas and capture high-resolution images and videos. This significantly reduces inspection time and associated labor costs.
Access hard-to-reach areas
Drones can easily reach areas that are difficult to reach with traditional inspection methods, such as the height, bottom, and other complex structures of bridges. This ensures comprehensiveness and accuracy of inspections.
What kind of drone is suitable for bridge inspections?
Currently, Skydio is using UAS systems for bridge inspection operations and is working closely with the U.S. Department of Transportation to speed up drone bridge inspections and improve inspection quality.
For bridge inspections, drone inspections require long and stable flights, capture high-quality image data, quickly detect potential hazards, and use images for photogrammetry to generate digital 3D models of structures.
Autel Robotics' enterprise drone Autel EVO MAX 4T can also contribute to bridge inspections. This is a semi-autonomous industrial drone that supports 8K 10X zoom, 720° obstacle avoidance, flight in a GPS-free environment, 42 minutes of flight time, and 20KM of image transmission distance.
Most bridge buildings are reinforced concrete structures, which is a major hidden danger for drones that rely on GPS to navigate and fly. This will seriously weaken the GPS signal, and the drone is prone to lose direction and obstacle avoidance failure. Autel EVO MAX series drones support anti-interference, can achieve obstacle avoidance and precise flight in a GPS-free environment, and are very suitable for bridge inspection tasks.
The future of bridge inspection drone pilots
The application of UAS in bridge inspection is on the rise, and the career development of bridge inspection drone pilots will also get better and better, and they will receive generous rewards. Professional drone photographers can easily learn to control remote-controlled drones for bridge inspections. During this period, drone pilots need to pass FAA certification and obtain drone licenses before they can carry out projects such as bridge inspections.
Summary
The application of drones in bridge inspections has significant advantages, which can improve safety, save time and costs, and provide detailed and accurate data. In the future, this technology will continue to develop and provide more efficient solutions for bridge maintenance and management.
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