Drone Inspection for Bridges – A Technology for Transformation?

When it comes to bridge inspection, the safety of the inspector and public, as well as the effectiveness of the technology, must be considered. Until now, most bridge inspections have been manual, providing subjective results that make it difficult for the bridge owner to budget maintenance and repairs. With the advent of drones, bridge inspections may soon be taking a whole new direction.

When you hear talk about what the next big thing in bridge inspection might be, the conversation quickly turns to drones. Discussions about the effectiveness of this technology, along with the safety and cost-saving it offers, are ongoing. Drone inspection for bridges is being tested by some bridge owners around the US in place of traditional methods. One would think that it cuts down the risk and cost involved while providing a helpful technology that would be more effective than earlier methods.

Why Drones?

Traditional methods of bridge inspection include manual inspection with the help of inspection vehicles, rope access or use of ladders, as well as aerial work platforms – depending upon the kind of bridge, evaluation, and the inspection area of the bridge.

Regardless of which part of the bridge must be assessed or which method is used for the inspection, the associated cost and hazard remain a big challenge. Ropes or ladders are dangerous to human life. Aerial work platforms used for aerial inspections are costly and require a high level of training and expertise to ensure safe usage.

Also, an inspection of a bridge poses unique challenges, which make it crucial to identify the right tool for the job to enhance the effectiveness of the process while cutting costs and time. The best thing about drone technology is that it serves many of these purposes. In the past few years, drones have undergone significant evolution and are becoming commercially viable.

Engineering companies are reluctant to adopt new technology as it takes away their traditional man-hours and billing time but as the infrastructure gets worse, a new way forward has to emerge. The use of drone inspections for bridges may be one of these.  

Does Drone Inspection Work?

There are many studies being conducted in various states about the viability of drones in infrastructure inspections. I see many states spending so much money on the same studies over and over again. Let me give you a summary of our experience with drones.

At Infraspect, we first worked on drones to inspect high mast light poles. Traffic would slow and swerve, which gave us pause. The inspection itself was not precise enough to use for high mast light pole inspections as well as very time-consuming as multiple runs were needed to achieve 100% coverage. Our team opted to develop a robotic crawler instead, which solved our mission of conducting an inspection that provided more quantitative data, was safer, faster, and could be conducted at a lower cost. We used the same principles as well as the FHWA and AASHTO guidelines to develop a high mast light pole inspection and repair robot. You can see both here. After the high mast light pole tests, we moved to bridge inspections. Drone inspections are ideal as part of the inspector’s toolkit to examine hard-to-reach areas from the water line to the bridge deck.

In early testing, many drones themselves had flaws that had to be overcome. I know in our early tests of drones for infrastructure inspections, the 12-15min. Flight time was too little to be of any use for infrastructure, so we developed a drone that could stay aloft for 55 minutes. That solved one issue. After a few initial tests in the field, we realized that flying drones above traffic would not work. It was distracting to drivers and could cause accidents on the road, so inspections over roadways had to be scrapped.

Where drone inspections did shine was between the water and the slab where the public could not see the drone in flight, on railroad bridges, and on tons of other infrastructure that was away from traffic or in harm’s way. Some natural uses for drone inspections were oil pipelines, construction site inspections, windmills, smokestacks, and dozens of other structures where a visual inspection was needed in a hard-to-reach place or large area. As technology advanced we could conduct crack inspections, locate leaks in pipelines and check any hard-to-reach area on a large bridge and report back any issues that were almost impossible to detect before. While drone inspections may not transform the industry the use of cool technology like drones may prompt bridge owners to start looking at other existing technologies to help advance the way inspections are conducted.

In addition, as drone technology does continue to improve, there will be dozens of other uses for drone inspections. For now, as far as bridge inspections, I would keep drones as just 1 tool in the inspector’s toolbox and keep them flying below traffic. If you would like to discuss a specific drone project, please fill out the form below.

Making Bridge Inspections More Effective With Drones

Infraspect is a nondestructive testing and robotic engineering company specializing in transportation infrastructure assessments and commercial engineering inspections.