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Evaluating the use of drones for timber bridge inspection


Junwon Seo
Luis Duque



Publication type:

General Technical Report (GTR)

Primary Station(s):

Forest Products Laboratory


Gen. Tech. Rep. FPL-GTR-258. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 1-152.


Bridge inspection using a drone, also referred to as an unpiloted aircraft system, has gained more interest in recent years among bridge owners, researchers, and stakeholders because of its efficiency and effectiveness. In fact, numerous bridges classified as structurally deficient in the United States that require more attention and effort for maintenance activities can be inspected using drones in an efficient manner. The primary goal of this project was to evaluate drones as supplemental bridge inspection tools for bridges that present accessibility challenges for inspectors. To accomplish this goal, an extensive literature review and technical survey were initially conducted to gain knowledge of the state-of-the-art and practices and critical considerations that should be accounted for while conducting inspections. Also, analysis of the drones was conducted and the most suitable drone for bridge inspections was selected. To recognize the drone-enabled inspection efficiency, preliminary inspections were conducted for structural damage identification in three structures, including a reinforced masonry building and two pedestrian timber deck bridges. With the knowledge and techniques established during the preliminary inspections, a six-stage recommended bridge inspection protocol using the drone was proposed and applied to two in-service highway timber bridges, including a timber arch bridge and a three-span timber girder bridge in South Dakota. Through the acquisition and analysis of image and video data, the effectiveness of the drone platform was evaluated in terms of image quality, damage identification and quantification, and comparisons with results from traditional inspections conducted on the bridges. This study details drone-enabled inspection advantages and challenges and provides conclusions and recommendations for future work. A key finding demonstrated throughout this project was that different types of structural damage on the bridges were efficiently identified using the drone.


Seo, Junwon; Wacker, James P.; Duque, Luis. 2018. Evaluating the use of drones for timber bridge inspection. Gen. Tech. Rep. FPL-GTR-258. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 1-152.


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